Unnamed: 0
int64 0
2.34M
| title
stringlengths 5
21.5M
| abst
stringlengths 1
21.5M
|
|---|---|---|
2,336,700 |
How can the evaluation of genetic tests be enhanced? Lessons learned from the ACCE framework and evaluating genetic tests in the United Kingdom.
|
Advances in genetic technology are increasing the availability of genetic tests, not only for rare single gene disorders, but also for common diseases such as breast and colo-rectal cancer. Before there can be widespread uptake of these tests, they must be evaluated to confirm the benefits of their use. But how should genetic tests be evaluated, given the speed at which new tests are emerging? One highly influential approach is the analytic validity, clinical validity, clinical utility and ethical, legal and social issues (ACCE) framework, which has provided a benchmark for the evaluation of genetic tests. The approach has been adopted and adapted by the United Kingdom Genetic Testing Network, with the help of the Public Health Genetics Unit in Cambridge, to evaluate new genetic tests for use in the National Health Service. We discuss a number of conceptual, methodological, and practical issues concerning the evaluation of genetic tests, based on lessons learned from applying the ACCE framework and from the UK experience, and make a number of recommendations to further strengthen the evaluation of genetic tests.
|
2,336,701 |
Cost-effectiveness of a school-based Tay-Sachs and cystic fibrosis genetic carrier screening program.
|
To explore the cost-effectiveness of school-based multi-disease genetic carrier screening.</AbstractText>Decision analysis of the cost-effectiveness of a school-based Tay-Sachs disease and cystic fibrosis genetic carrier screening program, relative to no screening. Data relating to ethnicity profile, test-accepting behavior, and screening program cost were sourced from an existing program in Sydney, Australia.</AbstractText>Compared to no screening, the incremental cost-effectiveness of the screening program is A dollar 5,834 per additional carrier detected. This cost-effectiveness ratio is most sensitive to changes in genetic test accuracy, and the cost of laboratory assays. The results imply a cost per affected birth avoided of approximately A dollar 530,000 (approximately US dollar 371,000).</AbstractText>This preconceptional genetic carrier screening program offers comparable cost-effectiveness to prenatal screening programs for cystic fibrosis.</AbstractText>
|
2,336,702 |
MELPREDICT: a logistic regression model to estimate CDKN2A carrier probability.
|
Heritable alterations in CDKN2A account for a subset of familial melanoma cases although no robust method exists to identify those at risk of being a mutation carrier.</AbstractText>We set out to construct a model for estimating CDKN2A mutation carrier probability using a cohort of 116 consecutive familial cutaneous melanoma patients evaluated at Massachusetts General Hospital Pigmented Lesion Center between April 2001 and September 2004. Germline CDKN2A and CDK4 status on the familial melanoma cases and clinical features associated with mutational status were then used to build a multiple logistic regression model to predict carrier probability and performance of model on external validation.</AbstractText>From the 116 kindreds prone to melanoma in the Boston area, 13 CDKN2A mutation carriers were identified and 12 were subsequently used in the modeling. Proband age at diagnosis, number of proband primaries, and number of additional family primaries were most closely associated with germline mutations. The estimated probability of the proband being a mutation carrier based on the logistic regression model (MELPREDICT) is given by e(L)/(1 + e(L) where L = 1.99+[0.92x(no. of proband primaries)]+[0.74x(no. of additional family primaries)]-[2.11xln(age)]. The mean estimated probabilities for subjects in the Boston dataset were 55.4% and 5.1% for the mutation carriers and non-carriers respectively. In a receiver operator characteristic analysis, the area under the curve was 0.881 (95% confidence interval 0.739 to 1.000) for the Boston model set (n = 116) and 0.803 (0.729 to 0.877) for an external Toronto hereditary melanoma cohort (n = 143).</AbstractText>These results represent the first-iteration logistic regression model to approximate CDKN2A carrier probability. Validation of this model with an external dataset revealed relatively robust performance.</AbstractText>
|
2,336,703 |
Screening the SPO11 and EIF5A2 genes in a population of infertile men.
|
Populations of infertile and fertile men were screened for mutations in SPO11 and EIF5A2, two infertility candidate genes. Three heterozygous amino acid changes that might contribute to infertility were identified in the infertile group.
|
2,336,704 |
Improved single-cell protocol for preimplantation genetic diagnosis of spinal muscular atrophy.
|
To develop and validate a simple and reliable single-cell analysis protocol for the preimplantation genetic diagnosis (PGD) of spinal muscular atrophy (SMA).</AbstractText>Molecular tests based on specific enzymatic digestion have already been described for SMA diagnosis. We modified the amplified DNA fragments so as to introduce a novel restriction site that provides an internal control for the completeness of the digestion.</AbstractText>The genetics and reproduction departments of two teaching hospitals.</AbstractText><AbstractText Label="PATIENT(S)" NlmCategory="METHODS">Six informed couples at risk of transmitting SMA.</AbstractText><AbstractText Label="INTERVENTION(S)" NlmCategory="METHODS">All patients underwent standard procedures associated with intracytoplasmic sperm injection.</AbstractText><AbstractText Label="MAIN OUTCOME MEASURE(S)" NlmCategory="METHODS">Improvement of SMA diagnostic efficiency and accuracy on single cell.</AbstractText><AbstractText Label="RESULT(S)" NlmCategory="RESULTS">One hundred fifty lymphocytes were analyzed with our protocol. One hundred percent diagnostic accuracy was achieved from both homozygous normal and SMN1-deleted leukocytes. Successful molecular analysis was achieved for 36 of 42 biopsied embryos (86%). Twenty-five normal embryos were transferred, but no pregnancy was achieved.</AbstractText><AbstractText Label="CONCLUSION(S)" NlmCategory="CONCLUSIONS">We developed an improved protocol for PGD of SMA that is simple, robust, and accurate; unfortunately, no pregnancies were achieved for any of the six patients who have undergone PGD in the program thus far.</AbstractText>
|
2,336,705 |
Gene expression and apoptosis induction in p53-heterozygous irradiated mice.
|
The role of the p53-genetic background in the expression of genes involved in either cell cycle checkpoint activation or apoptosis was evaluated in p53+/+ and p53+/- mouse strains at both basal levels and after DNA-induced damage. The spleen, colon, kidneys, lungs and liver of both strains were harvested from untreated animals and from mice exposed to 7.5 Gy of X-rays and sacrificed after 5 h. No significant differences were observed in the basal levels of p53 protein, CDKN1A and bax mRNA and spontaneous apoptosis, neither among the different organs within the same strain, nor between the same organ in the p53+/+ and p53+/- strains. After X-ray exposure, p53-dependent regulation was strikingly tissue-specific. In wild-type irradiated mice, p53 protein level increased after radiation treatment in all the organs analysed, whereas both CDKN1A and bax genes transcription increased in the spleen, colon and lungs, as assessed by means of quantitative RT-PCR. In p53+/- irradiated mice, on the contrary, a significant p53 induction was detected only in the spleen, while CDKN1A and bax genes levels increased in the spleen, colon and lungs, revealing the existence of different mechanisms of gene regulation in different organs. Apoptosis induction was observed in the spleen and colon of both strains, even if to lower extent in p53+/- mice compared to p53+/+ animals. In conclusion, in the spleen and colon, target gene transcription and apoptosis may be related to p53 genotype after DNA damage-induction. Moreover, our findings highlight the selectivity of p53 in transactivation following DNA damage in vivo, resulting in tissue-specific responses.
|
2,336,706 |
Loss of protein structure stability as a major causative factor in monogenic disease.
|
The most common cause of monogenic disease is a single base DNA variant resulting in an amino acid substitution. In a previous study, we observed that a high fraction of these substitutions appear to result in reduction of stability of the corresponding protein structure. We have now investigated this phenomenon more fully. A set of structural effects, such as reduction in hydrophobic area, overpacking, backbone strain, and loss of electrostatic interactions, is used to represent the impact of single residue mutations on protein stability. A support vector machine (SVM) was trained on a set of mutations causative of disease, and a control set of non-disease causing mutations. In jack-knifed testing, the method identifies 74% of disease mutations, with a false positive rate of 15%. Evaluation of a set of in vitro mutagenesis data with the SVM established that the majority of disease mutations affect protein stability by 1 to 3 kcal/mol. The method's effective distinction between disease and non-disease variants, strongly supports the hypothesis that loss of protein stability is a major factor contributing to monogenic disease.
|
2,336,707 |
Dissecting the attention deficit hyperactivity disorder (ADHD) phenotype: sustained attention, response variability and spatial attentional asymmetries in relation to dopamine transporter (DAT1) genotype.
|
ADHD is a childhood-onset behavioural disorder with a heterogeneous profile of neuropsychological impairment. Neuropsychological heterogeneity may, in part, reflect underlying genetic differences. Here we examined sustained attention, response variability and spatial attentional asymmetries in a sample of children and adolescents with ADHD (n=22) in relation to dopamine transporter genotype (DAT1) and also controls (n=20). Participants performed the sustained attention to response task (SART) (testing sustained attention and response variability) and the greyscales task (a perceptual measure of attentional bias). The latter has previously been shown to yield a robust leftward attentional asymmetry in healthy subjects. The 10-repeat allele of the DAT1 gene has been associated with ADHD in a number of studies and appears to have biological significance. The ADHD group was sub-divided into those individuals with two copies of the "high-risk" 10-repeat allele (high-risk DAT1) versus those with one or no copies of this allele (low-risk DAT1). The high-risk DAT1 ADHD group displayed greater response variability on the SART than either the low-risk DAT1 group or healthy controls, whereas the latter two groups did not differ. Further, the high-risk DAT1 group showed an attenuated spatial asymmetry, relative to the low-risk DAT1 ADHD group, who showed the typical leftward attentional asymmetry. Our results suggest that the 10-repeat DAT1 allele may mediate neuropsychological impairment in ADHD. The application of molecular genetics may help to define neuropsychological impaired subgroups of ADHD.
|
2,336,708 |
Preimplantation testing for chromosomal disorders improves reproductive outcome of poor-prognosis patients.
|
The clinical impact of PGD was evaluated through the analysis of the reproductive outcome before and after PGD in the same group of poor prognosis IVF patients, undergoing PGD for chromosomal abnormalities. Based on a series of 2359 PGD cycles, resulting in the establishment of 498 chromosomal abnormality-free clinical pregnancies, the reproductive history prior to PGD was analysed. Of 483 previous pregnancies analysed in patients with 432 pregnancies generated after PGD for aneuploidies, 328 (68%) ended in spontaneous abortions, in contrast to 28.4% after PGD, with only 155 (32%) resulting in deliveries, compared with 71.9% take-home baby rates after PGD. The patients experienced 315 previous IVF attempts, resulting in the transfer of 706 embryos in 308 cycles, of which only 49 (6.9%) implanted, compared with a 34.9% implantation rate observed in the same patients after PGD. Similar analysis of the previous reproductive outcomes of 45 carriers of balanced translocations achieving pregnancies following PGD, showed even stronger clinical impact, with a reduction of spontaneous abortions from 87.8% to 17.8%, and improvement of take-home baby rate from 11.5% to 81.4% after PGD. The results demonstrate a strong clinical impact of PGD, resulting in improvement of implantation rate, reduction of spontaneous abortions and increase in the take-home baby rate.
|
2,336,709 |
Overexpression of platelet-derived growth factor receptor alpha in breast cancer is associated with tumour progression.
|
Receptor tyrosine kinases have been extensively studied owing to their frequently abnormal activation in the development and progression of human cancers. Platelet-derived growth factor receptors (PDGFRs) are receptors with intrinsic tyrosine kinase activity that regulate several functions in normal cells and are widely expressed in a variety of malignancies. After the demonstration that gastrointestinal stromal tumours without c-Kit mutations harbour PDGFR-alpha-activating mutations and that PDGFR-alpha is also a therapeutic target for imatinib mesylate, the interest for this receptor has increased considerably. Because breast cancer is one of the most frequent neoplasias in women worldwide, and only one study has reported PDGFR-alpha expression in breast carcinomas, the aim of this work was to investigate the potential significance of PDGFR-alpha expression in invasive mammary carcinomas.</AbstractText>We used immunohistochemistry to detect PDGFR-alpha overexpression on a series of 181 formalin-fixed paraffin-embedded invasive ductal breast carcinomas and in two breast cancer cell lines: MCF-7 and HS578T. We associated its expression with known prognostic factors and we also performed polymerase chain reaction-single-stranded conformational polymorphism and direct sequencing to screen for PDGFR-alpha mutations.</AbstractText>PDGFR-alpha expression was observed in 39.2% of the breast carcinomas and showed an association with lymph node metastasis (P = 0.0079), HER-2 expression (P = 0.0265) and Bcl2 expression (P = 0.0121). A correlation was also found with the expression of platelet-derived growth factor A (PDGF-A; P = 0.0194). The two cell lines tested did not express PDGFR-alpha. Screening for mutations revealed alterations in the PDGFR-alpha gene at the following locations: 2500A-->G, 2529T-->A and 2472C-->T in exon 18 and 1701G-->A in exon 12. We also found an intronic insertion IVS17-50insA at exon 18 in all sequenced cases. None of these genetic alterations was correlated with PDGFR-alpha expression. The cell lines did not reveal any alterations in the PDGFR-alpha gene sequence.</AbstractText>PDGFR-alpha is expressed in invasive breast carcinomas and is associated with biological aggressiveness. The genetic alterations described were not correlated with protein expression, but other mechanisms such as gene amplification or constitutive activation of a signalling pathway inducing this receptor could still sustain PDGFR-alpha as a potential therapeutic target.</AbstractText>
|
2,336,710 |
Identification of unique reciprocal and non reciprocal cross packaging relationships between HIV-1, HIV-2 and SIV reveals an efficient SIV/HIV-2 lentiviral vector system with highly favourable features for in vivo testing and clinical usage.
|
Lentiviral vectors have shown immense promise as vehicles for gene delivery to non-dividing cells particularly to cells of the central nervous system (CNS). Improvements in the biosafety of viral vectors are paramount as lentiviral vectors move into human clinical trials. This study investigates the packaging relationship between gene transfer (vector) and Gag-Pol expression constructs of HIV-1, HIV-2 and SIV. Cross-packaged vectors expressing GFP were assessed for RNA packaging, viral vector titre and their ability to transduce rat primary glial cell cultures and human neural stem cells.</AbstractText>HIV-1 Gag-Pol demonstrated the ability to cross package both HIV-2 and SIV gene transfer vectors. However both HIV-2 and SIV Gag-Pol showed a reduced ability to package HIV-1 vector RNA with no significant gene transfer to target cells. An unexpected packaging relationship was found to exist between HIV-2 and SIV with SIV Gag-Pol able to package HIV-2 vector RNA and transduce dividing SV2T cells and CNS cell cultures with an efficiency equivalent to the homologous HIV-1 vector however HIV-2 was unable to deliver SIV based vectors.</AbstractText>This new non-reciprocal cross packaging relationship between SIV and HIV-2 provides a novel way of significantly increasing bio-safety with a reduced sequence homology between the HIV-2 gene transfer vector and the SIV Gag-Pol construct thus ensuring that vector RNA packaging is unidirectional.</AbstractText>
|
2,336,711 |
The future of prenatal diagnosis: rapid testing or full karyotype? An audit of chromosome abnormalities and pregnancy outcomes for women referred for Down's Syndrome testing.
|
To assess the implications of a change in prenatal diagnosis policy from full karyotype analysis to rapid trisomy testing for women referred primarily for increased risk of Down's Syndrome.</AbstractText>Retrospective collection and review of data.</AbstractText>The four London Regional Genetics Centres.</AbstractText>Pregnant women (32,674) in the London area having invasive prenatal diagnosis during a six-year three-month period.</AbstractText>Abnormal karyotypes and total number of samples referred for raised maternal age, raised risk of Down's Syndrome following serum screening or maternal anxiety were collected. Abnormal karyotypes detected by molecular trisomy detection were removed, leaving cases with residual abnormal karyotypes. These were assessed for their clinical significance. Pregnancy outcomes were ascertained by reviewing patient notes or by contacting obstetricians or general practioners.</AbstractText>Proportion of prenatal samples with abnormal karyotypes that would not have been detected by rapid trisomy testing, and the outcome of those pregnancies with abnormal karyotypes.</AbstractText>Results from 32,674 samples were identified, of which 24,891 (76.2%) were from women referred primarily for Down's Syndrome testing. There were 118/24,891 (0.47%) abnormal sex chromosome karyotypes. Of the samples with autosomal abnormalities that would not be detected by rapid trisomy testing, 153/24,891 (0.61%) were in pregnancies referred primarily for Down's Syndrome testing. Of these, 98 (0.39%) had a good prognosis (46/98 liveborn, 3/98 terminations, 1/98 intrauterine death, 1/98 miscarriage, 47/98 not ascertained); 37 (0.15%) had an uncertain prognosis (20/37 liveborn, 5/37 terminations; 12/37 not ascertained) and 18 (0.07%) had a poor prognosis (1/18 liveborn, 2/18 miscarriage, 11/18 terminations, 4/18 not ascertained).</AbstractText>For pregnant women with a raised risk of Down's Syndrome, a change of policy from full karyotype analysis to rapid trisomy testing would result in the failure to detect chromosome abnormalities likely to have serious clinical significance in approximately 0.06% (1 in 1659) cases. However, it should be noted that this figure may be higher (up to 0.12%; 1 in 833) if there were fetal abnormalities in some of the pregnancies in the uncertain prognosis group for which outcome information was not available.</AbstractText>
|
2,336,712 |
[Menkes' disease: heterozygosity testing by quantitative real-time PCR and the dilemma of therapeutic support].
|
Menkes' disease is a rare X-linked multisystemic lethal disorder of copper transport metabolism. Failure of synthesis of several copper enzymes explains most of the clinical features, which were characterised by neurodegenerative symptoms and connective tissue manifestations. Most cases are still prone to rapidly progressive cerebral degeneration and early death in the first few years. Since CNS-dysfunction usually preceeds development of the pathognomonic "steely" hair, delay of clinical diagnosis and onset of therapeutic intervention precludes longlasting neurological benefit. This is particularly true for patients with large deletions or severe truncations of the responsible ATP7A gene. We report on our own experience with a patient, who was diagnosed to be affected by Menkes' syndrome at the age of one year, due to the specific hair texture and biochemical abnormalities. Molecular investigation revealed a total deletion of exon 15 of the ATP7A gene. Heterozygosity was confirmed by means of real-time PCR in the child's mother, but could be excluded in the grandmother and other female relatives at risk. Therapeutic support with subcutaneous injection of copper-histidinate normalised diminished copper and coeruloplasmin serum levels, but was unable to influence the clinical course and to prevent the fatal outcome at the age of two years. This observation is in line with the experience of the literature claiming that currently available medication will hardly be able to normalise brain copper levels. However, observations of clinical variants of Menkes' disease with quite a different outcome and, more importantly, emerging of alternative copper transport pathways might still justify this time-limited therapeutic intervention.
|
2,336,713 |
Isolated loss of PMS2 expression in colorectal cancers: frequency, patient age, and familial aggregation.
|
Most colorectal cancers that have high levels of microsatellite instability (MSI-H) show loss of immunohistochemical expression of proteins that participate in the DNA mismatch repair process, most often involving MLH1 and MSH2. Less commonly, a third DNA mismatch repair protein, MSH6, may also be lost as the primary event. Rarely, tumors with MSI-H show normal expression of these three proteins. The genetic deficiency leading to the MSI-H phenotype in such cases is unknown. PMS2 is another member of the DNA mismatch repair complex. Its expression is generally lost in tumors with MLH1 loss of expression. Rarely, there is selective loss of PMS2 expression. We sought to describe the frequency and clinical correlates of selective loss of expression of PMS2 with the MSI-H tumor phenotype.</AbstractText>Two thousand seven hundred nineteen colorectal cancers from both clinic- and research-based ascertainment were studied. Tumor MSI testing and immunohistochemistry for MLH1, MSH2, MSH6, and PMS2 were conducted. Medical records were abstracted for age at diagnosis, gender, colorectal cancer site, and family history.</AbstractText>Five hundred thirty-five of the 2,719 tumors were MSI-H. Of these, 93% showed loss of expression of MLH1, MSH2, and/or MSH6. Thirty-eight showed normal expression for these proteins. PMS2 immunohistochemical staining was successful in 32 of 38 of these tumors. Of the 32, 23 showed selective loss of expression of PMS2. This was associated with young age of diagnosis and right-sided location but not with a striking family history of cancer.</AbstractText>Overall, 97% of the MSI-H tumors showed loss of expression for one or more of these four mismatch repair proteins. Selective loss of expression of PMS2 was present in 72% of cases in which colorectal cancers had an MSI-H phenotype but no alteration of expression of MLH1, MSH2, and MSH6. The underlying mechanism involved cannot be determined from this study but could involve point mutations in other DNA mismatch repair genes with retention of immunohistochemical expression, somatic inactivation of PMS2, or germ line mutation of PMS2.</AbstractText>
|
2,336,714 |
Cognitive performance is highly sensitive to prior experience in mice with a learning and memory deficit: failure leads to more failure.
|
The impact of a previously successful or unsuccessful experience on the subsequent acquisition of a related task is not well understood. The nature of past experience may have even greater impact in individuals with learning deficits, as their cognitive processes can be easily disrupted. Mice with a targeted disruption of the alpha and delta isoforms of the cAMP-response element-binding protein (CREB) gene (CREB(alphadelta-)-deficient mice) have a genetic vulnerability to impaired learning and memory that is highly influenced by experimental conditions. Thus, we studied the impact of prior successful and unsuccessful experiences on the degree to which CREB(alphadelta-)-deficient mice exhibit impaired spatial learning and memory in the Morris water maze (MWM). In Experiment 1, we replicated the cognitive deficit of CREB(alphadelta-)-deficient mice when given two trials per day with a 1-min intertrial interval (MWM2), and labeled this experience as a "failure." We rescued the deficit using four trials per day with a 3- to 5-min intertrial interval (MWM4) and labeled this experience a "success." In Experiment 2, a new, naive set of wild-type (WT) and CREB(alphadelta-)-deficient mice were randomly assigned to one of two sequence protocols to assess the influence of a success or a failure on subsequent performance. In Group 1, mice were first exposed to the MWM4 condition, followed by the more difficult MWM2 task. As expected, CREB(alphadelta-)-deficient mice performed well in the MWM4; they also performed well during reversal testing (MWM4R) where the goal location is changed. With this initial successful learning experience, the CREB(alphadelta-)-deficient mice then performed as well as WT mice in the MWM2, the condition in which they are known to be impaired. In contrast, CREB(alphadelta-)-deficient mice in Group 2 had an unsuccessful experience when first exposed to the MWM2 condition, and then also showed impairment in the MWM4, the condition in which they would normally perform well. This deficit was amplified when CREB(alphadelta-)-deficient mice were then tested in the reversal test. Sex differences in learning among CREB(alphadelta-)-deficient mice were amplified upon exposure to an unsuccessful learning experience. These data indicate that, under conditions of cognitive impairment, past experience can-depending on its nature-significantly facilitate or hinder future performance.
|
2,336,715 |
A mouse model recapitulating molecular features of human mesothelioma.
|
Malignant mesothelioma has been linked to asbestos exposure and generally has a poor prognosis because it is often diagnosed in advanced stages and is refractory to conventional therapy. Human malignant mesotheliomas accumulate multiple somatic genetic alterations, including inactivation of the NF2 and CDKN2A/ARF tumor suppressor genes. To better understand the significance of NF2 inactivation in malignant mesothelioma and identify tumor suppressor gene alterations that cooperate with NF2 loss of function in malignant mesothelioma pathogenesis, we treated Nf2 (+/-) knockout mice with asbestos to induce malignant mesotheliomas. Asbestos-exposed Nf2 (+/-) mice exhibited markedly accelerated malignant mesothelioma tumor formation compared with asbestos-treated wild-type (WT) littermates. Loss of the WT Nf2 allele, leading to biallelic inactivation, was observed in all nine asbestos-induced malignant mesotheliomas from Nf2 (+/-) mice and in 50% of malignant mesotheliomas from asbestos-exposed WT mice. For a detailed comparison with the murine model, DNA analyses were also done on a series of human malignant mesothelioma samples. Remarkably, similar to human malignant mesotheliomas, tumors from Nf2 (+/-) mice showed frequent homologous deletions of the Cdkn2a/Arf locus and adjacent Cdkn2b tumor suppressor gene, as well as reciprocal inactivation of Tp53 in a subset of tumors that retained the Arf locus. As in the human disease counterpart, malignant mesotheliomas from the Nf2 (+/-) mice also showed frequent activation of Akt kinase, which plays a central role in tumorigenesis and therapeutic resistance. Thus, this murine model of environmental carcinogenesis faithfully recapitulates many of the molecular features of human malignant mesothelioma and has significant implications for the further characterization of malignant mesothelioma pathogenesis and preclinical testing of novel therapeutic modalities.
|
2,336,716 |
Genome-wide identification and testing of superior reference genes for transcript normalization in Arabidopsis.
|
Gene transcripts with invariant abundance during development and in the face of environmental stimuli are essential reference points for accurate gene expression analyses, such as RNA gel-blot analysis or quantitative reverse transcription-polymerase chain reaction (PCR). An exceptionally large set of data from Affymetrix ATH1 whole-genome GeneChip studies provided the means to identify a new generation of reference genes with very stable expression levels in the model plant species Arabidopsis (Arabidopsis thaliana). Hundreds of Arabidopsis genes were found that outperform traditional reference genes in terms of expression stability throughout development and under a range of environmental conditions. Most of these were expressed at much lower levels than traditional reference genes, making them very suitable for normalization of gene expression over a wide range of transcript levels. Specific and efficient primers were developed for 22 genes and tested on a diverse set of 20 cDNA samples. Quantitative reverse transcription-PCR confirmed superior expression stability and lower absolute expression levels for many of these genes, including genes encoding a protein phosphatase 2A subunit, a coatomer subunit, and an ubiquitin-conjugating enzyme. The developed PCR primers or hybridization probes for the novel reference genes will enable better normalization and quantification of transcript levels in Arabidopsis in the future.
|
2,336,717 |
Genetically characterized positive control cell lines derived from residual clinical blood samples.
|
Positive control materials for clinical diagnostic molecular genetic testing are in critically short supply. High-quality DNA that closely resembles DNA isolated from patient specimens can be obtained from Epstein-Barr virus (EBV)-transformed peripheral blood lymphocyte cell lines. Here we report the development of a process to (a) recover residual blood samples with clinically important mutations detected during routine medical care, (b) select samples likely to provide viable lymphocytes for EBV transformation, (c) establish stable cell lines and confirm the reported mutation(s), and (d) validate the cell lines for use as positive controls in clinical molecular genetic testing applications.</AbstractText>A network of 32 genetic testing laboratories was established to obtain anonymous, residual clinical samples for transformation and to validate resulting cell lines for use as positive controls. Three panel meetings with experts in molecular genetic testing were held to evaluate results and formulate a process that could function in the context of current common practices in molecular diagnostic testing.</AbstractText>Thirteen laboratories submitted a total of 113 residual clinical blood samples with mutations for 14 genetic disorders. Forty-one EBV-transformed cell lines were established. Thirty-five individual point and deletion mutations were shown to be stable after 20 population doublings in culture. Thirty-three cell lines were characterized for specific mutations and validated for use as positive controls in clinical diagnostic applications.</AbstractText>A process for producing and validating positive control cell lines from residual clinical blood samples has been developed. Sustainable implementation of the process could help alleviate the current shortage of positive control materials.</AbstractText>
|
2,336,718 |
Clinical applications of whole-blood PCR with real-time instrumentation.
|
As the genetic basis of many human diseases is being discovered, there is increasing need for the detection of single-nucleotide polymorphisms/mutations in medical laboratories. We describe an innovative approach that combines PCR amplification directly on whole blood and real-time detection PCR technology (WB-RTD PCR).</AbstractText>We compared WB-RTD PCR with the method for extracted DNA-RTD PCR for the detection of mutations in the prothrombin (n = 94), factor V Leiden (n = 49), and hemochromatosis (n = 22) genes. Mutation detection on the Roche LightCycler was based on use of fluorescence resonance energy transfer (FRET) probes and melting curve analysis. We also compared the WB-RTD PCR on the LightCycler and the ABI Prismtrade mark 7700 sequence detection system with minor groove- binding nonfluorescent quencher probes.</AbstractText>We obtained complete concordance between both methods in assigning genotypes. We also demonstrated that the WB-RTD PCR method can be performed on real-time PCR instruments from Applied Biosystems and the LightCycler. Omission of the need for DNA extraction and gel electrophoresis allowed substantial labor and cost savings with this method.</AbstractText>This approach has applications for testing other medically relevant single-nucleotide polymorphisms.</AbstractText>
|
2,336,719 |
Forthcoming ethical issues in biological psychiatry.
|
Ethical issues in biological psychiatry are framed by (i) progress in the neurosciences, and (ii) a changing socio-cultural context. With regard to forthcoming neurotechniques to modify specifically defined brain functions by pharmacological substances with selective effects, by activating neuroplasticity including neurogenesis, or by implantation of neuronal tissues or computer-brain interfaces, etc., ethical problems will develop (i) at the border between therapy of diseases and enhancement of abilities in healthy people with regard to effects on society (e.g., social justice: equal access, loss of societal diversity) as well as on human value systems (e.g., personality, efforts, conditio humana), and (ii) at the border between the medical system and the wellness market with regard to financing what by whom? Ethical dilemmas in psychiatry develop (i) between the individual's best and the common good (demanded from outside medicine), (ii) among different ethical principles (inside medicine), iii) if solutions are influenced by personal reasons without observing ethical principles. Ethical guidelines are necessary for ethical orientation, but may protect against misconduct only (i) if psychiatrists are educated in ethics and (ii) if psychiatric acting is under continuous debate (by ethical review boards or the public). Thus, if we psychiatrists will become ethically sensitive by reflecting and perhaps solving our current ethical dilemmas we will be prepared to deal with forthcoming ethical issues in biological psychiatry.
|
2,336,720 |
Increased levels of CSF phosphorylated tau in apolipoprotein E epsilon4 carriers with mild cognitive impairment.
|
We investigated the correlation between the apolipoprotein E varepsilon4 allele (apoE epsilon4) carrier status, a major risk factor of Alzheimer's disease (AD), and levels of tau protein phosphorylated at threonine 231 (P-tau(231P)) in cerebrospinal fluid (CSF) in predementia and clinical stages of AD and healthy controls (HC). Thirty-one subjects with mild cognitive impairment (MCI) who had converted to AD during follow-up were included, as well as 71 AD patients, and 29 HC subjects. In MCI, but not in AD and HC, CSF P-tau(231P) levels were significantly higher in apoE epsilon4 carriers compared to non-carriers (p<0.001). Controlling for disease duration, the apoE epsilon4 effect on P-tau(231P) remained significant. Our study indicates that the apoE epsilon4 carrier status should be considered when CSF P-tau(231P) is evaluated as biomarker candidate of AD in MCI subjects.
|
2,336,721 |
Specialization of the entomopathogenic nematode Steinernema scapterisci with its mutualistic Xenorhabdus symbiont.
|
The level of specialization of the entomopathogenic nematode Steinernema scapterisci with its native Xenorhabdus symbiont was investigated by testing (1) the influence of non-native bacterial strains on nematode fitness within an insect-host (Galleria mellonella) and (2) specificity of the association between the nematode infective juveniles and non-native bacteria. All non-native Xenorhabdus spp. or Photorhabdus spp. strains tested were mutualistically associated with other entomopathogenic nematodes in nature. We showed that most of the Xenorhabdus spp. strains tested led to an insignificant difference of the nematode's fitness compared to the one obtained with the native bacterium. Conversely, Photorhabdus spp. strains almost entirely abolished nematode reproduction. The phylogenetic analysis of bacterial strains tested, showed that there was a negative correlation between S. scapterisci's reproduction rate with a bacterial strain and the genetic distance of this bacterial strain from the native one. We also showed that the native bacterium was the only one which was transmitted by S. scapterisci's infective juveniles. All these results, suggested a specialization between S. scapterisci and its native Xenorhabdus. As the same phenomenon was already demonstrated in the association between S. carpocapsae and X. nematophila, specialization between partners would not be an exception in entomopathogenic nematode-bacteria interactions. Nevertheless, S. scapterisci showed a dramatically higher compatibility with non-native Xenorhabdus spp. strains than did S. carpocapsae, suggesting differences in the co-evolutionary processes between nematodes and bacteria in these two model systems.
|
2,336,722 |
Characterization of the MacA-MacB efflux system in Neisseria gonorrhoeae.
|
A homologue of the MacA-MacB ABC transporter of Escherichia coli, which recognizes and exports macrolides, was identified in Neisseria gonorrhoeae. This study was undertaken to determine whether gonococci could use the MacA-MacB homologue to express decreased susceptibility to macrolides.</AbstractText>Techniques of DNA sequencing, gene cloning and expression of recombinant proteins in E. coli, gene mutation construction, transcriptional analysis and antimicrobial susceptibility testing were used in the study.</AbstractText>Although the gonococcal MacA-MacB efflux pump enhanced bacterial resistance to macrolides when overexpressed in an E. coli background, its loss in a gonococcal clinical isolate only slightly decreased bacterial resistance to azithromycin and erythromycin. However, a mutation in the -10 sequence of the promoter used in macAB expression enhanced the macrolide resistance of gonococci that produced a defective MtrC-MtrD-MtrE pump, which also recognizes macrolides.</AbstractText>The results from this study indicate that gonococci can employ both the MacA-MacB and MtrC-MtrD-MtrE efflux pumps to develop resistance to macrolides, particularly if mutations develop in the promoter that drives transcription of macAB.</AbstractText>
|
2,336,723 |
Self-regulation and the behavioural response to DNA risk information: a theoretical analysis and framework for future research.
|
The few studies conducted to date suggest that DNA risk information may be less likely to achieve behaviour change than other types of health risk information. We draw upon self-regulation theory to explain and predict the characteristics of risk information that are more and less likely to motivate behaviour change. Self-regulation theory describes how information about a health threat is processed within individuals' pre-existing cognitive schema, and how the cognitive representations within these schemas activate coping procedures for dealing with the perceived threat. We explore the proposition that the initial impact of information about a health threat depends upon how well it "fits" with existing cognitive representations of that threat. For example, in one study DNA risk information regarding an inherited form of bowel cancer was perceived as more accurate and had a greater impact on risk perceptions in those whose representation of the threat included genes as the single cause, as opposed to one of several. Since the cognitive representation of a threat activates coping procedures that fit with that representation, we also explore the proposition that cognitive representations of a threat that has a genetic identity are less likely to activate coping procedures that include risk-reducing behaviours. For example, using DNA risk information to assess an inherited predisposition to heart disease increased the extent to which the condition was seen as caused by genes, which in turn reduced the expectation that a behavioural means of coping would be effective (eating a low fat diet), but increased the expectation that a biological means was effective (taking lipid lowering medication). Describing the heuristics that operate between risk information, the cognitive representations of threat and coping procedures could be used to identify the cognitions to target so as to optimize the motivational impact of DNA and other risk information.
|
2,336,724 |
[The use of DNA analysis for diagnostics of hereditary premature ovarian failure].
|
Methods of DNA-analysis of 769G --> A mutations in INHalpha1 gene and CGG-repeats polymorphism in FMRI gene have been developed for creating test-systems for genetically caused forms of premature ovarian failure (POF) diagnostics. The frequency of 769G --> A mutation among women population in Ukraine was established and, by preliminary calculations, makes up 2.8%. Results of analysis of CGG-repeats numbers in FMRI gene in the group of 215 women (oocyte donors) revealed five persons with CGG-repeats numbers, that exceeds the normal one (42 copies). Thus the frequency of persons with allels with high risk of premutation in FMRI gene is 2.3%. The results of our research confirm the actuality of genetic tests of mutations in INHalpha1 and FMR1 genes among the women of reproductive age with the purpose of POF prognosis and prevention the birth of children with fragile X syndrome.
|
2,336,725 |
Pharmacogenetic testing in the clinical management of schizophrenia: a decision-analytic model.
|
Clinical application of pharmacogenetic testing has been proposed as a means of improving treatment outcomes in psychiatry. The identification of a putative genetic test for better clozapine response in schizophrenia offers an opportunity to evaluate the cost-effectiveness of such testing. The authors performed a cost-effectiveness analysis of a genetic test that may identify individuals with greater likelihood of responding to clozapine treatment. We modeled a target population of schizophrenia patients in an acute psychotic episode, using a lifetime time horizon and societal perspective. Outcome measures included life expectancy, quality-adjusted life expectancy, costs, and incremental cost-effectiveness. Effects of variations in testing parameters were also examined. For a 30-year-old with schizophrenia, applying the pharmacogenetic test and treating those predicted to respond to clozapine with clozapine-first cost US $47,705 per additional quality-adjusted life-year, compared with treating all patients with conventional agents and reserving clozapine for treatment-resistant patients. In 1-way sensitivity analyses, test sensitivity and cost had the greatest impact on the incremental cost-effectiveness. We conclude that pharmacogenetic tests may achieve utility in clinical psychiatry, although their cost-effectiveness depends on several clinical parameters. More consistent reporting of test parameters such as sensitivity and specificity would greatly facilitate assessment of future pharmacogenetic studies.
|
2,336,726 |
Comparison efficiency of the artificial intelligence methods for the diagnosis of Acid - base and anion gap disorders.
|
Diagnosis of the most complicated disorders in acid-base status and accompanying electrolyte balance creates a lot of troubles for practicing physicians. The purpose of our study was to create and compare: 1) an artificial neural network, 2) genetic program, 3) fuzzy-neural system that can diagnose acid-base disorders, based on a set of laboratory gasometric and electrolyte measurements. We took into account 7 single acid-base disorders, 11 double acid-base disorders and 6 triple complicated disorders with accompanying anion gap alterations. We prepared a set laboratory measurements consisting of 250 results for training and the same number of results for testing the program. Finally, the efficiency of presented artificial intelligence (AI) methods has been described and compared.
|
2,336,727 |
Bioinformatics meets clinical informatics.
|
The field of bioinformatics has exploded over the past decade. Hopes have run high for the impact on preventive, diagnostic, and therapeutic capabilities of genomics and proteomics. As time has progressed, so has our understanding of this field. Although the mapping of the human genome will certainly have an impact on health care, it is a complex web to unweave. Addressing simpler "Single Nucleotide Polymorphisms" (SNPs) is not new, however, the complexity and importance of polygenic disorders and the greater role of the far more complex field of proteomics has become more clear. Proteomics operates much closer to the actual cellular level of human structure and proteins are very sensitive markers of health. Because the proteome, however, is so much more complex than the genome, and changes with time and environmental factors, mapping it and using the data in direct care delivery is even harder than for the genome. For these reasons of complexity, the expected utopia of a single gene chip or protein chip capable of analyzing an individual's genetic make-up and producing a cornucopia of useful diagnostic information appears still a distant hope. When, and if, this happens, perhaps a genetic profile of each individual will be stored with their medical record; however, in the mean time, this type of information is unlikely to prove highly useful on a broad scale. To address the more complex "polygenic" diseases and those related to protein variations, other tools will be developed in the shorter term. "Top-down" analysis of populations and diseases is likely to produce earlier wins in this area. Detailed computer-generated models will map a wide array of human and environmental factors that indicate the presence of a disease or the relative impact of a particular treatment. These models may point to an underlying genomic or proteomic cause, for which genomic or proteomic testing or therapies could then be applied for confirmation and/or treatment. These types of diagnostic and therapeutic requirements are most likely to be introduced into clinical practice through traditional forms of clinical practice guidelines and clinical decision support tools. The opportunities created by bioinformatics are enormous, however, many challenges and a great deal of additional research lay ahead before this research bears fruit widely at the care delivery level.
|
2,336,728 |
A comparison study: applying segmentation to array CGH data for downstream analyses.
|
Array comparative genomic hybridization (CGH) allows detection and mapping of copy number of DNA segments. A challenge is to make inferences about the copy number structure of the genome. Several statistical methods have been proposed to determine genomic segments with different copy number levels. However, to date, no comprehensive comparison of various characteristics of these methods exists. Moreover, the segmentation results have not been utilized in downstream analyses.</AbstractText>We describe a comparison of three popular and publicly available methods for the analysis of array CGH data and we demonstrate how segmentation results may be utilized in the downstream analyses such as testing and classification, yielding higher power and prediction accuracy. Since the methods operate on individual chromosomes, we also propose a novel procedure for merging segments across the genome, which results in an interpretable set of copy number levels, and thus facilitate identification of copy number alterations in each genome.</AbstractText>http://www.bioconductor.org</AbstractText>
|
2,336,729 |
Association of the IL12RB1 promoter polymorphisms with increased risk of atopic dermatitis and other allergic phenotypes.
|
Atopic dermatitis (AD) is frequently associated with eosinophilia, highly elevated immunoglobulin E (IgE) levels and increased levels of T-helper 2-type (Th2) cytokines in skin lesions due to infiltrating T cells. Interleukin-12 (IL-12), in combination with interferon-gamma (IFN-gamma), inhibits IgE synthesis and Th2 cell function. As the IFN-gamma-inducing cytokines IL-12 and IL-23 utilize IL-12Rbeta1 as part of their receptors, it is possible that polymorphic variants of the IL-12Rbeta1 (IL12RB1) gene might determine an individual's susceptibility to AD. Here, we carried out a systemic search for genetic variants of the human IL12RB1 in Japanese subjects and identified 48 genetic variants. In a case-control association study, we found that promoter polymorphisms -111A/T and -2C/T were significantly associated with an increased risk of AD under a recessive model. The -111T-allele frequency in the independent population of child asthmatics was also much higher than that in the control group. In addition, the -111T/T genotype was progressively more common in AD with high total serum IgE levels in an IgE-level-dependent manner. Deletion analysis of the IL12RB1 promoter suggested that the -265 to -104 region that contained the -111A/T polymorphic site harbored an important regulatory element. Furthermore, we showed that the -111A/T substitution appeared to cause decreased gene transcriptional activity such that cells from -111A/A individuals exhibited higher IL12RB1 mRNA levels than those from -111T allele carriers. Our results suggested that in individuals with the -111T/T genotype, reduced IL-12Rbeta1 expression may lead to increased Th2 cytokine production in the skin and contribute to the development of AD and other subsequent allergic diseases.
|
2,336,730 |
Molecular analysis in diagnostic procedure of hearing impairment in newborns.
|
To determine the proportion of newborns diagnosed with hearing impairment through the hearing impairment screening program in newborns, and the frequency of 35delG/GJB2 mutation as a cause of hearing impairment. The results of the study imply the integration of the mutation analysis in the neonatal screening program.</AbstractText>Evoked otoacustic emission (E-OAE) screening program was performed among 6019 newborns at the Department of Obstetrics and Gynaecology, Rijeka University Hospital Center, between October 2002 and December 2004. Newborns diagnosed with hearing impairment were re-examined after three weeks and if abnormal responses persisted, the diagnosis was evaluated by auditory brainstem evoked response (ABER) testing. Children with confirmed diagnosis were examined by allele-specific polymerase chain reaction to identify the presence of 35delG/GJB2 mutation.</AbstractText>After the first and second stage of screening, 86 newborns were suspect of having hearing impairment. ABER confirmed the diagnosis of hearing impairment in 14 children. Molecular analysis revealed 35delG/GJB2 mutation in 2 of 8 children analyzed. The mutation was homozygous in one, and heterozygous in the other child.</AbstractText>Neonatal hearing impairment screening is useful for early diagnosis of hearing impairment. It should be complemented with the 35delG/GJB2 mutation analysis, because the identification of the mutation and the etiologic diagnosis might improve the medical treatment and genetic counselling of patients and families with hearing impairment.</AbstractText>
|
2,336,731 |
Isolation and characterization of an anti-recombinant erythropoietin single-chain antibody fragment using a phage display antibody library.
|
The production of a large amount of specific antibodies against erythropoietin (EPO) is necessary for both clinical treatment and doping control. However, the weak immunogenicity of EPO and the side effects of excessive injection make the conventional immunological protocol rather inefficient and time-consuming. In this study, a single-chain antibody fragment of variable region (scFv) against recombinant human erythropoietin (rHuEPO) was produced after three rounds of panning a phage display antibody library. The selected scFv-B2 was expressed in soluble form in Escherichia coli DH5alpha F' and purified by His-bond nickel affinity chromatography with a yield of about 1-2 mg of antibody in 1 L of the culture supernatant. The molecular weight of the scFv was estimated to be 29 kDa by sodium dodecyl sulfate polyacrylamide gel electrophoresis and the affinity constant was found to be 1.0 x 10(8) L mol(-1) based on a competitive indirect enzyme-linked immunosorbent assay (CI-ELISA). The potential ability of the scFvs for immunopurification of rHuEPO from related sample was demonstrated by using a double-antibody sandwich ELISA. The reported method is a very powerful tool to produce specific antibodies for rHuEPO detection demands.
|
2,336,732 |
Genetic approaches for the identification of apoptotic components.
|
Jun amino-terminal kinase (JNK) mediates a physiological stress signal that leads to cell death. However, the role of the JNK pathway in intrinsic cell death execution mechanisms is largely unknown. In a genetic screen for dominant suppressors of Reaper (Rpr)-induced cell death, we identified Drosophila chromosomal regions that contain genes which are homologous to apoptosis signal-regulating kinase (ASK1) and Drosophila tumor necrosis factor receptor-associated factor 1 (DTRAF1). We present evidence that the killer signal initiates the JNK pathway via proteasome-mediated degradation of Drosophila inhibitor of apoptosis protein 1 (DIAP1) to promote cell death.
|
2,336,733 |
A clinic-based study of the LRRK2 gene in Parkinson disease yields new mutations.
|
Referral-based studies indicate that a mutation (G2019S) in exon 41 of the LRRK2 gene might be a common cause of Parkinson disease (PD). The authors sequenced leucine-rich repeat kinase 2 (LRRK2) exons 31, 35, and 41 in 371 consecutively recruited patients with PD and found mutations in six (1.6%) subjects, including two heterozygous for new putative pathogenic variants (R1441H, IVS31 + 3A-->G). These data confirm the important contribution of LRRK2 to PD susceptibility in a clinic-based population.
|
2,336,734 |
LRRK2 mutations in Parkinson disease.
|
To determine the frequency of LRRK2 mutations in idiopathic Parkinson disease (PD), the authors studied 786 PD probands, 32 affected siblings, 1,044 unaffected siblings, and 278 unrelated controls. The authors designed allelic discrimination assays for nine LRRK2 mutations and identified these in six probands with PD, one affected sibling, one unaffected sibling, and one unrelated control. Thus LRRK2 mutations only rarely cause idiopathic PD.
|
2,336,735 |
LRRK2 gene in Parkinson disease: mutation analysis and case control association study.
|
In addition to the four well-confirmed genes linked to early-onset Parkinson disease (PD) (SNCA, PARKIN, DJ-1, and PINK1), mutations in the leucine-rich repeat kinase 2 gene (LRRK2) have recently been identified in families with autosomal dominant late-onset PD.</AbstractText>To perform mutation analysis of LRRK2 in probands of families showing dominant inheritance of PD and to conduct a case control association study to test the hypothesis that common coding variations might be associated with increased susceptibility to PD.</AbstractText>All 51 LRRK2 coding exons were sequenced in 23 probands and the mutation frequencies were evaluated in 180 neurologically normal control subjects. For the association study the authors genotyped four coding LRRK2 polymorphisms in 250 normal control subjects and 121 patients with PD (predominantly white patients of Canadian origin), 84% of whom had age at onset before 50 years and 42% had a positive family history.</AbstractText>The authors identified three probands with heterozygous LRRK2 mutations: two of them have the known G2019S substitution and one proband has a novel I1371V substitution. Mutation analysis of a large family demonstrated complete segregation of the G2019S with PD. However, there was no association between PD and any of the four polymorphisms at the allelic or genotypic levels (p > 0.17). Furthermore, the authors did not detect a modifying effect for any genotype or of APOE genotypes upon the age at onset in the PD group (p > 0.20).</AbstractText>The results support the prior suggestion that LRRK2 mutations cause PD. The disease in the families reported here presents a phenotype indistinguishable from typical PD. All three families demonstrate a very variable age at onset that is not explained by APOE genotypes. The common coding variations in the LRRK2 gene neither constitute strong PD risk factors nor modify the age at onset; however, the possibility of a modest risk effect remains to be assessed in large datasets.</AbstractText>
|
2,336,736 |
Analysis of chromosome 1 microsatellite markers and the FHM2-ATP1A2 gene mutations in migraine pedigrees.
|
The aims of the study were: (i) to extend our linkage analysis of chromosome 1q microsatellite markers in predominantly migraine with aura pedigrees and (ii) to test the novel FHM-2 ATP1A2 gene for involvement in these migraine affected pedigrees and a previous pedigree (MF14) showing evidence of linkage of markers to C1q31.</AbstractText>A chromosome 1 scan (31 markers) was performed in 21 multiplex pedigrees affected predominantly with migraine with aura (MA). The known FHM-2 ATP1A2 gene mutations were tested, by sequencing, for the involvement in MA and migraine without aura (MO) in these pedigrees. Sequencing was performed in the coding areas of the ATP1A2 gene through three MA individuals from MF14.</AbstractText>Evidence for linkage was obtained at C1q23 to markers spanning the ATP1A2 gene. However, testing of the known ATP1A2 gene mutations (for FHM) in common migraine probands of pedigrees showing excess allele sharing was negative. Sequencing of the entire coding areas of the gene through all the three MA affected from MF14 was also negative for mutations.</AbstractText>Microsatellite markers on chromosome 1q23 show evidence of excess allele sharing in MA and some MO pedigrees, suggesting linkage to the common forms of migraine and the presence of a susceptibility gene in this region. The FHM-2 (ATP1A2 gene) does not seem to be involved in the common types of migraine. Despite certain clinical characteristics, the genetic correlation between FHM and familial typical migraine remains unclear. Several candidate genes lie within the C1q23 and C1q31 cytogenetic regions; therefore, further studies are needed.</AbstractText>
|
2,336,737 |
HIV-1 subtypes in Spain: a retrospective analysis from 1995 to 2003.
|
To perform a retrospective analysis of all HIV-1 non-B variants circulating in Spain from 1995 to 2003 and extend their virological characterization.</AbstractText>Samples from a total of 396 HIV-infected subjects with epidemiological suspicion of being infected with non-B clades were analysed during the study period. Subtyping was carried out on the protease (PR), reverse transcriptase (RT) and envelope (env) genes.</AbstractText>PR sequences belonging to non-B subtypes were recognized in 43.2% of cases (23 A, 13C, 6D, 3F, 118 G, 3H, 4 J and 1 U). Subtype G and AG recombinants were the most frequent variants (69%), and were found most often in subjects from West and Central Africa. Up to 70% of pol (PR, RT) sequences belonging to subtype G harboured env sequences belonging to clade A (55%), B (13.8%) or K (3.4%). Nearly half were mosaic GA viruses, and a few were CRF 14 BG viruses. Up to 14 new recombinant viruses, which could not be assigned to previously described circulating recombinant forms (CRFs), were found.</AbstractText>There is great diversity in the HIV-1 variants and recombinant viruses circulating in Spain. Non-B sequences may be underestimated if only the env region is examined in phylogenetic analyses. Drug resistance testing provides the advantage of pol subtyping, and its additional use for this purpose should be encouraged.</AbstractText>
|
2,336,738 |
Fitness of Cry1A-resistant and -susceptible Helicoverpa armigera (Lepidoptera: Noctuidae) on transgenic cotton with reduced levels of Cry1Ac.
|
The performance of Helicoverpa armigera (Hübner) on 15-wk-old cotton plants was compared for a susceptible strain, a near-isogenic laboratory-selected strain, and F1 progeny of the two strains. Glasshouse experiments were conducted to test the three insect types on conventional plants and transgenic plants that produced the Bacillus thuringiensis (Bt) toxin Cry1Ac. At the time of testing (15 wk), the Cry1Ac concentration in cotton leaves was 75% lower than at 4 wk. On these plants, < 10% of susceptible larvae reached the fifth instar, and none survived to pupation. In contrast, survival to adulthood on Cry1Ac cotton was 62% for resistant larvae and 39% for F1 larvae. These results show that inheritance of resistance to 15-wk-old Cry1Ac cotton is partially dominant, in contrast to results previously obtained on 4-wk-old Cry1Ac cotton. Growth and survival of resistant insects were similar on Cry1Ac cotton and on non-Bt cotton, but F1 insects developed more slowly on Cry1Ac cotton than on non-Bt cotton. Survival was lower and development was slower for resistant larvae than for susceptible and F1 larvae on non-Bt cotton. These results show recessive fitness costs are associated with resistance to Cry1Ac.
|
2,336,739 |
Lisch nodules after trabeculectomy.
|
The development of Lisch nodules in an eye that had undergone trabeculectomy with mitomycin C is described. Complete ophthalmologic examinations and genetic testing of a 12-year-old boy were performed. Lisch nodules can develop after trabeculectomy without the systemic manifestations of neurofibromatosis type 1.
|
2,336,740 |
Molecular diagnostic testing for inherited thrombophilia using Invader.
|
Physicians in the United States and Europe began testing patients who had idiopathic thrombotic events for inherited risk factors in 1990s. The College of American Pathologists (CAP) offered proficiency testing for molecular genetic screening for thrombophilia in 1997. Today, a hypercoagulable workup including screening for inherited thrombophilia defects is becoming part of the standard of care in many parts of the world (1). Who, what, and when to test continue to be controversial and challenging questions (2); however, laboratories developing new or improved mutation detection methodologies have used the most commonly screened inherited thrombophilia polymorphism, factor V Leiden (R506Q), for many years (3). In the most recent CAP survey (MGL-A 2003), the most commonly employed method used in one-third of all participating clinical laboratories testing for factor V Leiden and prothrombin G20210A was the non-PCR-based method called Invader, developed by Third Wave Technologies. The remainder of the clinical laboratories reported testing for these variants using PCR-restriction fragment length polymorphism (RFLP), allele-specific PCR, and allele-specific hybridization. Emerging mutation detection technologies include DNA resequencing approaches such as pyrosequencing (4) fluorescence polarization detection (5), genotyping on microelectronic DNA chips like Nanogen's nanochip (6), and oligonucleotide hybridization with photocrosslinking (7). Invader technology is currently a medium-throughput, 96-well plate format assay that is sufficient for most hospital clinical laboratories. Although this assay format is not currently performed in a microarray format, Invader is amenable to performance on a solid support; specifically, the reaction can be performed on the surface of microspheres and the resulting fluorescence measured using flow cytometry (8). This chapter presents the method as well as some suggestions for utilizing the Invader system for mutation/polymorphism screening in general and for thrombophilia testing in particular.
|
2,336,741 |
Sex ratio distortion in offspring of families with BRCA1 or BRCA2 mutant alleles: an ascertainment bias phenomenon?
|
There has been controversy regarding whether BRCA1 germline mutations favor female births or whether the sex imbalances observed are attributable to ascertainment bias. Our aims were to compare the sex ratios among offspring of BRCA1-positive, BRCA2-positive, and BRCA-negative families undergoing genetic testing in clinical programs, and to determine whether ascertainment bias is responsible for the observed preponderance of female offspring.</AbstractText>A total of 145 breast and/or ovarian cancer families with mutations in BRCA1 (n = 83) or BRCA2 (n = 62), and 90 families without identifiable mutation were collected for the study from familial cancer clinics in Barcelona, Spain, and Boston, US. Sex ratio was analyzed among all births in the families and offspring of all (tested and obligate) carriers. In order to minimize the effect of family history of cancer, the analysis was also performed among offspring of the most recent generation of mutation-positive carriers who did not have affected children and compared with a control group comprised of the offspring of the most recent adult generation of non-carriers from families with a known mutation.</AbstractText>There was a statistically higher proportion of female births in all groups (BRCA1 59% (95% CI = 57-61%), BRCA2 58% (56-61%), and BRCA-negative 59% (56-61%), respectively). The female preponderance persisted in analyses limited to offspring of BRCA1 and BRCA2 carriers (61% (57-65%), and 62% (58-66%), respectively), with no differences between the two mutation groups. In contrast, the excess of female offspring disappeared when ascertainment or recall biases were minimized, 44% (37-52%), and 39% (26-53%) for BRCA1; 51% (44-58%), and 46% (33-60%) for BRCA2.</AbstractText>Our findings suggest that there is no asymmetry in birth outcomes among BRCA1 or BRCA2 mutations carriers. Rather ascertainment bias in families participating in genetic testing, or in the family history information they provide is likely to account for excess of female offspring previously reported.</AbstractText>
|
2,336,742 |
G6PD Viangchan (871G>A) is the most common G6PD-deficient variant in the Cambodian population.
|
Glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common hereditary enzymopathy among Southeast Asians. We studied G6PD mutations in 108 migrant Cambodian laborers in Chanthaburi province and cord blood samples from 107 Cambodian newborns at Buriram Hospital. Thirty-one (26.1%) of 119 Cambodian males and three of 96 (3.1%) females were G6PD deficient and were assayed for G6PD mutations. G6PD Viangchan (871G>A) was identified in most G6PD-deficient Cambodians (28 of 34; 82.4%); G6PD Union (1360C>T) and G6PD Coimbra (592C>T) was found in one case each. We concluded that G6PD Viangchan (871G>A) was the most common mutation among Cambodians. This finding is similar to G6PD-deficient Thais and Laotians, suggesting a common ancestry of people from these three countries.
|
2,336,743 |
Small heat shock protein 27 mutation in a Japanese patient with distal hereditary motor neuropathy.
|
Heat shock protein 27 (HSP27) belongs to a family of small heat shock proteins that play significant roles in the cellular stress response and are also involved in the control of protein-protein interactions as chaperons. Mutation in HSP27 has been identified as the cause of axonal Charcot-Marie-Tooth disease (CMT) and distal hereditary motor neuropathy (HMN). Heat shock protein 22 (HSP22) is a molecular counterpart of HSP27, and its mutation is another cause of distal HMN. We screened the mutation of HSP27 and HSP22 in 68 Japanese patients with axonal CMT or unclassified CMT and six Japanese patients with distal HMN. We detected a heterozygous P182S mutation of HSP27 in a patient with distal HMN, but we found no mutations in HSP22. Mutation in HSP27 may impair the formation of the stable neurofilament network that is indispensable for the maintenance of peripheral nerves.
|
2,336,744 |
A common nonsense mutation in EphB2 is associated with prostate cancer risk in African American men with a positive family history.
|
The EphB2 gene was recently implicated as a prostate cancer (PC) tumour suppressor gene, with somatic inactivating mutations occurring in approximately 10% of sporadic tumours. We evaluated the contribution of EphB2 to inherited PC susceptibility in African Americans (AA) by screening the gene for germline polymorphisms.</AbstractText>Direct sequencing of the coding region of EphB2 was performed on 72 probands from the African American Hereditary Prostate Cancer Study (AAHPC). A case-control association analysis was then carried out using the AAHPC probands and an additional 183 cases of sporadic PC compared with 329 healthy AA male controls. In addition, we performed an ancestry adjusted association study where we adjusted for individual ancestry among all subjects, in order to rule out a spurious association due to population stratification.</AbstractText>Ten coding sequence variants were identified, including the K1019X (3055A-->T) nonsense mutation which was present in 15.3% of the AAHPC probands but only 1.7% of 231 European American (EA) control samples. We observed that the 3055A-->T mutation significantly increased risk for prostate cancer over twofold (Fisher's two sided test, p = 0.003). The T allele was significantly more common among AAHPC probands (15.3%) than among healthy AA male controls (5.2%) (odds ratio 3.31; 95% confidence interval 1.5 to 7.4; p = 0.008). The ancestry adjusted analyses confirmed the association.</AbstractText>Our data show that the K1019X mutation in the EphB2 gene differs in frequency between AA and EA, is associated with increased risk for PC in AA men with a positive family history, and may be an important genetic risk factor for prostate cancer in AA.</AbstractText>
|
2,336,745 |
Preimplantation genetic screening reveals a high incidence of aneuploidy and mosaicism in embryos from young women undergoing IVF.
|
In order to assess the frequency of aneuploidy and mosaicism in embryos obtained from IVF patients aged <38 years, preimplantation genetic screening (PGS) was performed after biopsy of two blastomeres. Furthermore, the reliability of this diagnosis was assessed by performing reanalysis of the embryo on day 5.</AbstractText>The copy numbers of 10 chromosomes (1, 7, 13, 15, 16, 18, 21, 22, X and Y) were investigated by fluorescence in situ hybridization (FISH) analysis. Embryos that were found to be abnormal or of insufficient morphological quality were cultured until day 5 and reanalysed. Results obtained were compared to the day 3 blastomere analysis.</AbstractText>After analysis of 196 embryos (one cell in 38% and two cells in 62%), only 36% of the embryos were found to be normal on day 3. After analysis of two blastomeres, 50% showed chromosomal mosaicism. Comparison of the FISH results from day 3 blastomeres and day 5 embryos yielded an overall cytogenetic confirmation rate of 54%.</AbstractText>The rates of mosaicism and aneuploidy in these embryos from young IVF patients are similar to those published for older women. We found the best confirmation rate after a diagnosis based on two cells, where both blastomeres showed the same chromosomal abnormality. In contrast, after a mosaic diagnosis the confirmation rate was low. The present study provides the first detailed reanalysis data of embryos analysed by PGS and clearly demonstrates the impact of mosaicism on the reliability of the PGS diagnosis.</AbstractText>
|
2,336,746 |
Prognostic and therapeutic significance of myeloma genetics and gene expression profiling.
|
Molecular diagnostic tools and novel therapeutics now offer the potential for accurate prognostic and personalized treatment road maps for patients with multiple myeloma (MM). We will review the evidence and provide specific recommendations for routine clinical molecular genetic testing and use of such information to guide therapeutic decision making. In particular, the negative prognostic impact of specific IgH translocations such as the t(4;14), t(14;16), chromosome 13 deletion by conventional cytogenetics and loss of 17p13 by interphase fluorescence in situ hybridization are now established. Preliminary gene expression profiling studies have also demonstrated that individual genes (CSK1-B) or groups of genes can define prognosis with greater accuracy than conventional genetic markers and can provide pharmacogenomic and biologic insight into the pathophysiology, therapeutics, and future targets of myeloma. Importantly, we recommend that all clinical trials now adopt routine genetic testing and risk stratification.
|
2,336,747 |
GJB2 mutations and additional disabilities in a pediatric cochlear implant population.
|
Children with severe to profound sensorineural hearing loss due to GJB2 mutations have often been deemed good cochlear implant candidates. Studies on children with GJB2 mutations and cochlear implants have typically excluded children with additional disabilities.</AbstractText>To investigate the presence of additional disabilities among children with and without GJB2 mutations in a cochlear implant population.</AbstractText>A retrospective chart review was performed of children with non-syndromic sensorineural hearing loss (SNHL) who received a cochlear implant between 1993 and 2004.</AbstractText>Among 108 children within the cochlear implant database; 46 patients met the inclusion criteria of idiopathic non-syndromic hearing loss. Sixteen children had GJB2 mutations, 12 were GJB2 negative, and 17 did not receive GJB2 testing but had no other identifiable etiology or risk factor contributing to hearing loss. The proportion of children with additional disabilities that would affect either pre-operative assessments or post-operative results in the GJB2 positive group was 44% compared to 33% of children in the GJB2 negative. Additional disabilities were present in 41% of the children who did not receive GJB2 testing. The disabilities in the GJB2 positive group included specific learning disability, apraxia, epileptiform aphasia, attention deficit disorder, global developmental delay, and gross motor delay. The GJB2 negative and those children not receiving GJB2 testing had motor delays, language delay, autism, specific learning disability, and attention deficit disorder. The proportion of children with at least 6 months CI use who relied on oral communication was 62% in the GJB2 positive group, 66% in the GJB2 negative group, and 38% in the untested group. A majority of the genetic alleles were 35delG (81%) and 10 of 16 (63%) patients with GJB2 mutations were homozygous 35delG. The rate of developmental diagnoses was similar in patients with homozygous GJB2 compared to compound heterozygous genotypes.</AbstractText>The presence of biallelic GJB2 mutations does not rule out non-hearing related disorders that can have an effect on speech, language and learning. Forty-four percent of children with GJB2 mutations had other conditions that could directly affect pre-implant evaluation and post-implant performance. This rate is similar to the reported prevalence among the overall population of children with hearing loss. All children should have a comprehensive evaluation of development and behavior regardless of the etiology of hearing loss.</AbstractText>
|
2,336,748 |
Cadaveric sperm induces intergeneric androgenesis in the fish, Hemigrammus caudovittatus.
|
Intergeneric androgenetic golden Buenos Aires tetra (BT), Hemigrammus caudovittatus was generated using sperm drawn from post-mortem males preserved at -20 degrees C for 10, 20, 30 and 40 days or fresh sperm to activate the UV-irradiated oocytes of black widow tetra (WT), Gymnocorymbus ternetzi. UV-irradiation (4.2 W/m(2)) of the oocytes for 3 min inactivated their nuclear genome. Fry hatched out from these activated oocytes were haploids; suffering haploid syndrome, they died before or within 48 h after hatching. Fresh BT sperm activated 95% oocytes; however, the sperm drawn from post-mortem males preserved at -20 degrees C for 60 (within glycerol packing) and 30 days (without glycerol packing) activated only 24 and 19% oocytes, respectively. Following activation, diploidy was restored by shocking the 25-min-old embryos at 41 degrees C for 2 min. Nuclear genomic inactivation of the oocytes was confirmed by (i) production of 100% haploids, (ii) karyotype and erythrocyte measurements, (iii) phenotypic markers, (iv) progeny testing and (v) species-specific marker. At hatching, survival of androgenotes decreased from 11% for those induced with fresh sperm to 4% for those generated using sperm from 30-day-old post-mortem males. Reproductive performance of the 'fresh' and 'cadaveric' F(0) and F(1) androgenetic males (Y(2)Y(2)) was superior to the control (X(1)Y(2)). Crosses involving homozygous (Y(2)Y(2)) 'fresh' F(0) androgenetic males with heterozygous females (X(1)X(2)) and F(0) homozygous males (Y(2)Y(2)) with females (X(2)X(2)) produced 2-4% unexpected female progenies. Paternal autosomes, inherited by the homozygous androgenetic female (X(2)X(2)), induced the production of female progenies in significantly less number of crosses than the crosses with heterozygous females (X(1)X(2)), which carried equal number of paternal and maternal autosomes. PCR analyses of the genomic DNA of normal male and unexpected F(1) and F(2) female progenies amplified by DMRT 1 specific primer produced bands of 237 and 300 bp length, and thereby confirmed that these unexpected females were genetic males. RAPD analyses of the androgenetic progenies showed that their genome was not contaminated with maternal genome.
|
2,336,749 |
[Microarray CGH: principle and use for constitutional disorders].
|
Chips technology has allowed to miniaturize process making possible to realize in one step and using the same device a lot of chemical reactions. The application of this technology to molecular cytogenetics resulted in the development of comparative genomic hybridization (CGH) on microarrays technique. Using this technique it is possible to detect very small genetic imbalances anywhere in the genome. Its usefulness has been well documented in cancer and more recently in constitutional disorders. In particular it has been used to detect interstitial and subtelomeric submicroscopic imbalances, to characterize their size at the molecular level or to define the breakpoints of translocation. The challenge today is to transfer this technology in laboratory medicine. Nevertheless this technology remains expensive and the existence of numerous sequence polymorphisms makes its interpretation difficult. Finally its is unlikely that it will make karyotyping obsolete as it does not allow to detect balanced rearrangements which after meiotic segregation might result in genome imbalance in the progeny.
|
2,336,750 |
A biogeographic pattern in sparrow bill morphology: parallel adaptation to tidal marshes.
|
The study of ecological convergence, the evolution of similar traits on multiple occasions in response to similar conditions, is a powerful method for developing and testing adaptive hypotheses. However, despite the great attention paid to geographic variation and the foraging ecology of birds, surprisingly few cases of convergent or parallel feeding adaptations have been adequately documented. In this study, we document a biogeographic pattern of parallel bill morphology across 10 sparrow taxa endemic to tidal marshes. All North American tidal marsh sparrows display parallel differentiation from close relatives in other habitats, suggesting that selection on bill morphology is strong. Relative to their body mass, tidal marsh sparrows have longer, thinner bills than their non-tidal marsh counterparts, which is likely an adaptation for consuming more invertebrates and fewer seeds, as well as for probing in sediment crevices to capture prey. Published data on tidal marsh food resources and diet of the relevant taxa support this hypothesis. This morphological differentiation is most pronounced between sister taxa with the greatest estimated divergence times, but is found even in taxa that show little or no structure in molecular genetic markers. We, therefore, speculate that tidal marsh ecosystems are likely settings for ecological speciation.
|
2,336,751 |
Origin and rapid diversification of a tropical moss.
|
Molecular sequences rarely evolve at a constant rate. Yet, even in instances where a clock can be assumed or approximated for a particular set of sequences, fossils or clear patterns of vicariance are rarely available to calibrate the clock. Thus, obtaining absolute timing for diversification of natural lineages can prove difficult. Unfortunately, without absolute time we cannot develop a complete understanding of important evolutionary processes, including adaptive radiations and key innovations. In the present study, the coding sequence of the nuclear gene, glyceraldehyde 3-phosphate dehydrogenase (gpd), extracted from the paleotropical moss, Mitthyridium, was found to exhibit clocklike behavior and used to reconstruct the history of 80 distinct molecular lineages that cover the full geographic range of Mitthyridium. Two separate clades endemic to two geographically distinct oceanic archipelagos were revealed by this phylogenetic analysis. This allowed the use of island age (as derived from potassium-argon dating) as a maximum age of origin of each monophyletic group, providing two independent time anchors for the clock found in gpd, the final piece needed to study absolute time. Based on results from both maximum age calibrations, which separately yielded highly consistent estimates, the ancestor of this moss group arose approximately 8 million years ago, and then diversified at the rapid rate of 0.56 +/- 0.004 new lineages per million years. Such a rate is on par with the highest diversification rates reported in the literature including rapidly radiating insular groups like the Hawaiian silversword alliance, a classic example of an adaptive radiation. Using independent sources of data, it was found that neither the age nor diversification estimates were affected by the use of molecular lineages rather than species as the operational taxonomic units. Identifying the cause for this rapid diversification requires further testing, but it appears to be related to a general shift in reproductive strategy from sexual to asexual, which may be a key innovation for this young group.
|
2,336,752 |
Complete trisomy 1q with mosaic Y;1 translocation: a recurrent aneuploidy presenting diagnostic dilemmas.
|
We present a case of a liveborn male with complete trisomy 1q in mosaic form due to a de novo unbalanced translocation. There are seven previously documented cases of complete trisomy for 1q, which demonstrate that this is a lethal condition. All cases have similar phenotype including weights greater than 50th centile for gestational age, hydrocephalus, microphthalmia, abnormal ears, small mouth or jaw, and abnormal fingers. Single umbilical artery, imperforate anus, and dysplastic kidneys are also seen in more than one patient. Five of the eight translocation cases have identical chromosomal breakpoints involving 1q and Yq. This suggests the possibility of sequence similarities on these two chromosomes as has been documented with several other recurrent chromosomal rearrangements. Further, this case demonstrates the need for postnatal genetics evaluation following prenatal diagnosis. In postnatal testing, the aneuploidy could not be demonstrated in metaphase cells from cultured lymphocytes. More detailed testing prompted by abnormal amniocentesis and neonatal dysmorphology was necessary to confirm the cytogenetic diagnosis. Without the prenatal diagnosis, it is likely that the true cytogenetic aberration would have gone undetected.
|
2,336,753 |
A pilot study testing the genetic polymorphism of N-acetyltransferase 2 as a risk factor in lung cancer.
|
NAT2 as phase II enzyme is involved in the detoxification/activation of various drugs, environmental substances and carcinogenic compounds. A genotyping approach has been used to investigate NAT2 genotype with putative relevance in lung cancer in population of 110 Slovak-Caucasians patients and 167 non-malignant individuals from the same region. Slow acetylation was not observed to be a significant risk factor of lung cancer development (OR=1.19; 95% CI: 0.71-1.99). However, one genotype responsible for slow acetylation (NAT2*5B/*6) was observed significantly more frequently in lung cancer patients with squamous cell carcinoma compared with control subjects (OR=2.24; 95% CI: 1.14-4.34). Stratified analysis showed an increasing impact of the specific allelic combination NAT2*5B/*6 in non-smokers (OR=6.5; 95% CI: 1.25-15.08). In the case of squamous lung carcinoma an analysis revealed a tendency to adversely affect cancer risk in the individuals with the mentioned genotype in younger than 60 years (OR=3.14; 95% CI: 0.98-9.72) non-smokers (OR=10.40; 95% CI: 1.35-118.89) and in females (OR=4.25; 1.08-16.25). Additional studies are needed to confirm the results we observed and to assess the impact of other effects (specific allelic combinations, sex differences and histological subtype of lung cancer) on NAT2 susceptibility in lung carcinogenesis.
|
2,336,754 |
The protistan origins of animals and fungi.
|
Recent molecular studies suggest that Opisthokonta, the eukaryotic supergroup including animals and fungi, should be expanded to include a diverse collection of primitively single-celled eukaryotes previously classified as Protozoa. These taxa include corallochytreans, nucleariids, ministeriids, choanoflagellates, and ichthyosporeans. Assignment of many of these taxa to Opisthokonta remains uncorroborated as it is based solely on small subunit ribosomal RNA trees lacking resolution and significant bootstrap support for critical nodes. Therefore, important details of the phylogenetic relationships of these putative opisthokonts with each other and with animals and fungi remain unclear. We have sequenced elongation factor 1-alpha (EF-1alpha), actin, beta-tubulin, and HSP70, and/or alpha-tubulin from representatives of each of the proposed protistan opisthokont lineages, constituting the first protein-coding gene data for some of them. Our results show that members of all opisthokont protist groups encode a approximately 12-amino acid insertion in EF-1alpha, previously found exclusively in animals and fungi. Phylogenetic analyses of combined multigene data sets including a diverse set of opisthokont and nonopisthokont taxa place all of the proposed opisthokont protists unequivocally in an exclusive clade with animals and fungi. Within this clade, the nucleariid appears as the closest sister taxon to fungi, while the corallochytrean and ichthyosporean form a group which, together with the ministeriid and choanoflagellates, form two to three separate sister lineages to animals. These results further establish Opisthokonta as a bona fide taxonomic group and suggest that any further testing of the legitimacy of this taxon should, at the least, include data from opisthokont protists. Our results also underline the critical position of these "animal-fungal allies" with respect to the origin and early evolution of animals and fungi.
|
2,336,755 |
XPD Lys751Gln polymorphism in the etiology and outcome of childhood acute myeloid leukemia: a Children's Oncology Group report.
|
Genetic polymorphisms result in interindividual variation in DNA repair capacity and may, in part, account for susceptibility of a cell to genotoxic agents and to malignancy. Polymorphisms in XPD, a member of the nucleotide excision repair pathway, have been associated with development of treatment-related acute myeloid leukemia (AML) and with poor outcome of AML in elderly patients. We hypothesized that XPD Lys751Gln polymorphism may play a role in causation of AML in children and, as shown in adults, may affect the outcome of childhood AML therapy. Genotyping of 456 children treated for de novo AML was performed at XPD exon 23. Genotype frequencies in patients were compared with healthy control subject frequencies, and patient outcomes were analyzed according to genotype. Gene frequencies in AML patients and healthy controls were similar. There were no significant differences in overall survival (P = .82), event-free survival (P = .78), treatment-related mortality (P = .43), or relapse rate (RR) (P = .92) between patients with XPD751AA versus 751AC versus 751CC genotypes, in contrast to reports in adult AML. These data, representing the only data in pediatric AML, suggest that XPD genotype does not affect the etiology or outcome of childhood AML.
|
2,336,756 |
An adaptable microvalving system for on-chip polymerase chain reactions.
|
On-chip genetic analysis systems are beginning to provide a viable alternative to conventional gene profiling and amplification devices, through minimal reagent use, high detection resolution, and the potential for high-throughput parallel testing of the genetic material, even from single cells. Despite the advantages, there are many difficulties inherent in creating an integrated microfluidic diagnostic platform. One major challenge is the accurate control and manipulation of fluid, and particularly the immobilization of reaction mixtures during heating phases of polymerase chain reactions (PCR). In this paper we present a pumping and valving system based on the use of three servomotor-controlled valve fingers that actuate microchannels within a poly-dimethylsiloxane (PDMS) fluidic chip. We characterize the valving ability of the system in terms of fluid loss and show the successful fluid retention of the system over 35-cycle PCR runs at temperatures of up to approximately 96 degrees C. In addition, we demonstrate the system's ability to perform PCR by successfully amplifying a sample of beta2 microglobulin transcript obtained from the peripheral blood of a patient with multiple myeloma. This work has proven to be a successful approach to multi-use valving and a viable method of alleviating the fluid control difficulties inherent in performing a PCR reaction in an on-chip environment. In addition, it opens the door for further automation and integration with other chip-based genetic analysis platforms.
|
2,336,757 |
Characterization and subgrouping of Campylobacter concisus strains using protein profiles, conventional biochemical testing and antibiotic susceptibility.
|
To characterize and subgroup clinical strains of Campylobacter concisus isolated from patients with gastrointestinal disease.</AbstractText>A total of 109 C. concisus isolates from 98 patients obtained between June 1997 and December 1998 were analysed using protein profiles, conventional biochemical tube tests, ApiCampy, and susceptibility patterns by Neosensitabs and E-test.</AbstractText>Two groups were identified by using protein profiles. One resembled the ATCC 33237 type strain of oral origin, and a second group differing from it, particularly in the high molecular weight zone. Considerable diversity exists in the lower molecular range of the gels, also within assigned subgroups. Biochemical testing showed differences between the groups in the ability to reduce nitrate, ApiCampy testing also yielded differences between the two assigned groups, although reactions were highly heterogeneous. Resistance to erythromycin, ciprofloxacin, ampicillin, ceftriaxone and tetracycline occurred in 3%, 13%, 7%, 11% and 0% of the isolates when using Neosensitabs. The E-test yielded comparable results 7%, 5%, 0%, 2% and 3%, respectively.</AbstractText>Results indicate that C. concisus can be assigned to two broad groups based on differences in protein profiles. No distinct phenotypic marker was identified. Susceptibility patterns are not suitable for discrimination between the two assigned groups. Further studies using a polyphasic approach including the application of genetic methods are needed to assess the complex taxonomy of this potential pathogen.</AbstractText>
|
2,336,758 |
N-ethyl-N-nitrosourea mutagenesis: boarding the mouse mutant express.
|
In the mouse, random mutagenesis with N-ethyl-N-nitrosourea (ENU) has been used since the 1970s in forward mutagenesis screens. However, only in the last decade has ENU mutagenesis been harnessed to generate a myriad of new mouse mutations in large-scale genetic screens and focused, smaller efforts. The development of additional genetic tools, such as balancer chromosomes, refinements in genetic mapping strategies, and evolution of specialized assays, has allowed these screens to achieve new levels of sophistication. The impressive productivity of these screens has led to a deluge of mouse mutants that wait to be harnessed. Here the basic large- and small-scale strategies are described, as are the basics of screen design. Finally, and importantly, this review describes the mechanisms by which such mutants may be accessed now and in the future. Thus, this review should serve both as an overview of the power of forward mutagenesis in the mouse and as a resource for those interested in developing their own screens, adding onto existing efforts, or obtaining specific mouse mutants that have already been generated.
|
2,336,759 |
Mutations in the glucocerebrosidase gene and Parkinson disease: phenotype-genotype correlation.
|
Mutations in the glucocerebrosidase (GBA) gene have been recently identified as contributory to Parkinson disease (PD) in Ashkenazi Jews. In the present study, the clinical characteristics of Ashkenazi patients with PD with GBA mutations (n = 40) were compared to those of Ashkenazi patients with PD without any known GBA mutation (n = 108). The overall clinical manifestations and age at disease onset did not differ in patients with GBA mutations compared to patients without mutations.
|
2,336,760 |
Research and practice opportunities at the intersection of health education, health behavior, and genomics.
|
Researchers and practitioners in health behavior and health education (HBHE) can play a pivotal leadership role in the integration of genomic advances to improve the public's health. The purpose of this article is to outline research and practice opportunities at the intersection of genomics and HBHE. We begin this article by briefly summarizing the existing evidence in the literature pertaining to the public's use of genetic services, the effectiveness of genetic counseling, and the impact of genetic testing. Following this, we outline and expand on several areas that we believe are ripe for further exploration, understanding, and public health application:(a) public understanding of genetic information, (b) interventions for health behavior change, and (c) public health assurance and advocacy. This analysis has identified the need to consider potential application efforts in genomics and HBHE from an ecological perspective, with an emphasis on multiple levels of intervention and analysis.
|
2,336,761 |
Marketing genetic tests: empowerment or snake oil?
|
Genetic tests are currently being offered to the general public with little oversight and regulation as to which tests are allowed to be sold clinically and little control over the marketing and promotion of sales and use. This article provides discussion and data to indicate that the general public holds high opinions of genetic testing and that current media outlets for public education on genetic testing are not adequate to increase accurate knowledge of genetics. The authors argue that more regulation is needed to control and correct this problem in the United States.
|
2,336,762 |
Contributions of public health to genetics education for health care professionals.
|
With growing knowledge about the role of genetics in health, genetics education for health care professionals has taken on increasing importance. Many efforts are under way to develop new genetics curricula. Although such efforts are primarily the responsibility of health professional schools and professional societies, the public health system is an important stakeholder, and different sectors of public health have opportunities to enhance educational efforts. These include the development of authoritative information sources about the clinical utility of genetic susceptibility and pharmacogenetic tests, creation of networks that link professionals in underserved regions to educational materials and consultative backup, and sponsorship of forums for multidisciplinary discussion of controversial issues. Public health input can help to ensure an appropriate emphasis on health outcomes as new genomic tests and technologies come into use, thus helping to protect society from the social and medical costs of genetic tests with limited clinical value.
|
2,336,763 |
Enhanced counseling for women undergoing BRCA1/2 testing: impact on subsequent decision making about risk reduction behaviors.
|
The authors evaluated the impact of an enhanced counseling intervention, designed to promote well-informed decision making for follow-up risk reduction options for ovarian cancer, among high-risk women undergoing BRCA1/2 testing (N = 77). Following standard genetic counseling, participants received either an enhanced counseling session--designed to help participants anticipate their reactions to possible test outcomes and plan for postresult consequences--or a general health information control session. One week after disclosure of test results, women in the enhanced counseling group experienced a greater reduction in avoidant ideation, suggesting more complete processing of risk feedback. At the 6-month follow-up, intervention respondents reported seeking out more information about prophylactic oophorectomy and were more likely to have actually undergone preventive surgery. The results indicate that the use of enhanced counseling can play an important role in decision making about risk reduction behaviors following BRCA1/2 testing.
|
2,336,764 |
Will genetic testing for complex diseases increase motivation to quit smoking? Anticipated reactions in a survey of smokers.
|
The aim of this study was to improve understanding of smokers' potential reactions to genetic testing for smoking-related diseases. One thousand twenty-four respondents completed a postal survey; 186 were smokers. Questions addressed anticipated psychological and behavioral reactions to genetic test results using hypothetical scenarios. Of smokers, 65% anticipated being motivated to quit smoking upon receiving a positive genetic test result; 39% anticipated being demotivated by a negative result. More smokers anticipated being depressed in response to receiving a positive result for cancer than for heart disease (40% vs. 24%). Anticipated motivation was associated with higher desire to quit and lower nicotine addiction, anticipated depression with poorer understanding of genetic testing, and anticipated demotivation with lower education. Smokers who have a high desire to quit may use genetic testing as a motivational tool. Understanding of genetics may be important in determining how individuals respond to genetic tests for complex diseases.
|
2,336,765 |
Assessment of an interactive computer-based patient prenatal genetic screening and testing education tool.
|
The Enhancing Patient Prenatal Education study tested the feasibility and educational impact of an interactive program for patient prenatal genetic screening and testing education. Patients at two private practices and one public health clinic participated (N = 207). The program collected knowledge and measures of anxiety before and after use of the tool. Time in various prenatal visit activities was collected prior to and after the introduction of the education tool. Providers completed an assessment of their experiences with patients who had used the program. Results indicate that patient knowledge significantly increased from pre to post (p = .0001) with no increase in anxiety (p = .31). Time in clinic activities, including overall visit time, increased. A majority of providers indicated that the program disrupted clinic flow. This assessment suggests that the program increases patient knowledge and does not increase patient anxiety. However, challenges remain to using this program in a clinic setting.
|
2,336,766 |
Management of the patient and family with neurofibromatosis 2: a consensus conference statement.
|
A consensus conference on neurofibromatosis 2 (NF2) was held in 2002 at the request of the United Kingdom (UK) Neurofibromatosis Association, with particular emphasis on vestibular schwannoma (VS) surgery. NF2 patients should be managed at specialty treatment centres, whose staff has extensive experience with the disease. All NF2 patients and their families should have access to genetic testing because presymptomatic diagnosis improves the clinical management of the disease. Some clinical manifestations of NF2, such as ocular abnormalities, can be detected in infancy; therefore, clinical screening for at-risk members of NF2 families can start at birth, with the first magnetic resonance (MRI) scan at 10-12 years of age. Minimal interference, maintenance of quality of life, and conservation of function or auditory rehabilitation are the cornerstones of NF2 management, and the decision points to achieve these goals for patients with different clinical presentations are discussed.
|
2,336,767 |
Estimation of the frequency of occult mutations for an autosomal recessive disease in the presence of genetic heterogeneity: application to genetic hearing loss disorders.
|
The routine testing for pathologic mutation(s) in a patient's DNA has become the foundation of modern molecular genetic diagnosis. It is especially valuable when the phenotype shows genetic heterogeneity, and its importance will grow as treatments become genotype specific. However, the technology of mutation detection is imperfect and mutations are often missed. This can be especially troublesome when dealing with a recessive disorder where the combination of genetic heterogeneity and missed mutation creates an imprecision in the genotypic assessment of individuals who do not appear to have the expected complement of two pathologic mutations. This article describes a statistical approach to the estimation of the likelihood of a genetic diagnosis under these conditions. In addition to providing a means of testing for missed mutations, it also provides a method of estimating and testing for the presence of genetic heterogeneity in the absence of linkage data. Gene frequencies as well as estimates of sensitivity and specificity can be obtained as well. The test is applied to GJB2 recessive nonsyndromic deafness, Usher syndrome types Ib and IIa, and Pendred-enlarged vestibular aqueduct syndrome.
|
2,336,768 |
Screening for new MTHFR polymorphisms and NTD risk.
|
The enzyme, 5,10-methylenetetrahydrofolate reductase (MTHFR) plays a key role in cellular folate metabolism. The A222V (677C->T) polymorphism is a confirmed neural tube defect (NTD) risk factor within Irish and other populations. To search for other unknown single nucleotide polymorphisms (SNPs) that might play a role in the etiology of NTDs, we examined the entire MTHFR coding region in healthy individuals (n = 100). SNPs were identified using sequencing and database analysis and allele frequencies were determined in our Irish population. We identified P39P (116C->T; T allele frequency 0.13) and previously reported R594Q (1793G->A; Q allele frequency 0.07). We screened a large ethnically homogeneous Irish NTD cohort (n>1,300) for P39P and R594Q. A possible association between NTD cases and P39P (P = 0.034) was found but this was not confirmed by transmission disequilibrium testing. R594Q also showed some evidence of a NTD case association (P = 0.07). Further analysis indicated these observations are due to linkage disequilibrium with A222V (677C->T), and therefore these new SNPs are unlikely to be independent risk factors for NTDs. As rates of NTDs differ between ethnic groups, we examined allele and genotype frequencies of P39P and R594Q within African-American and American-Caucasian populations. This is the first NTD association study of both R594Q and the novel P39P. The association with NTD risk reported for these SNPs is driven by the linkage disequilibrium with the A222V (677C->T) NTD risk factor.
|
2,336,769 |
Microsatellite marker analysis as a typing system for Candida glabrata.
|
Candida glabrata is one of the most important causes of nosocomial fungal infection. We investigated, using a multiplex PCR, three polymorphic microsatellite markers, RPM2, MTI, and ERG3, in order to obtain a rapid genotyping method for C. glabrata. One set of primers was designed for each locus, and one primer of each set was dye labeled to read PCR signals using an automatic sequencer. Eight reference strains including other Candida species and 138 independent C. glabrata clinical isolates were tested. The clinical isolates were collected from different anatomical sites of adult patients either hospitalized in different wards of two different hospitals or not hospitalized. Since C. glabrata is haploid, one single PCR product for each PCR set was obtained and assigned to an allele. The numbers of different alleles were 5, 7, and 15 for the RPM2, MTI, and ERG3 loci, respectively. The number of allelic associations was 21, leading to a discriminatory power of 0.84. The markers were stable after 25 subcultures, and the amplifications were specific for C. glabrata. A factorial correspondence analysis did not indicate any correlation between the 21 multilocus genotypes and the clinical data (source, sex, ward, anatomical sites). Microsatellite marker analysis is a rapid and reliable technique to investigate clinical issues concerning C. glabrata. However, its discriminatory power should be improved by testing other polymorphic microsatellite loci.
|
2,336,770 |
Genetic risk assessment and BRCA mutation testing for breast and ovarian cancer susceptibility: systematic evidence review for the U.S. Preventive Services Task Force.
|
Clinically significant mutations of BRCA1 and BRCA2 genes are associated with increased susceptibility for breast and ovarian cancer. Although these mutations are uncommon, public interest in testing for them is growing.</AbstractText>To determine benefits and harms of screening for inherited breast and ovarian cancer susceptibility in the general population of women without cancer presenting for primary health care in the United States.</AbstractText>MEDLINE (1966 to 1 October 2004), Cochrane Library databases, reference lists, reviews, Web sites, and experts.</AbstractText>Eligibility was determined by inclusion criteria specific to key questions about risk assessment, genetic counseling, mutation testing, prevention interventions, and potential adverse effects.</AbstractText>After review of studies, data were extracted, entered into evidence tables, and summarized by using descriptive or statistical methods. Study quality was rated by using predefined criteria.</AbstractText>Tools assessing risks for mutations and referral guidelines have been developed; their accuracy, effectiveness, and adverse effects in primary care settings are unknown. Risk assessment, genetic counseling, and mutation testing did not cause adverse psychological outcomes, and counseling improved distress and risk perception in the highly selected populations studied. Intensive cancer screening studies are inconclusive. Chemoprevention trials indicate risk reduction for breast cancer in women with varying levels of risk, as well as increased adverse effects. Observational studies of prophylactic surgeries report reduced risks for breast and ovarian cancer in mutation carriers.</AbstractText>No data describe the range of risk associated with BRCA mutations, genetic heterogeneity, and moderating factors; studies conducted in highly selected populations contain biases; and information on adverse effects is incomplete.</AbstractText>A primary care approach to screening for inherited breast and ovarian cancer susceptibility has not been evaluated, and evidence is lacking to determine benefits and harms for the general population.</AbstractText>
|
2,336,771 |
Genetic risk assessment and BRCA mutation testing for breast and ovarian cancer susceptibility: recommendation statement.
|
This statement summarizes the U.S. Preventive Services Task Force (USPSTF) recommendations on genetic risk assessment and BRCA mutation testing for breast and ovarian cancer susceptibility, along with the supporting scientific evidence. The complete information on which this statement is based, including evidence tables and references, is included in the evidence synthesis available through the USPSTF Web site (http://www.preventiveservices.ahrq.gov). The recommendation is also posted on the Web site of the National Guideline Clearinghouse (http://www.guideline.gov).
|
2,336,772 |
A new tool in the battle against Alzheimer's disease and aging: ex vivo gene therapy.
|
Alzheimer's disease (AD) is the most common cause of severe dementia in the aging population and is caused by a loss of many different neural systems throughout the brain associated with memory. Amongst the many neural systems affected, large cholinergic projection neurons that innervate large regions of cortex are particularly vulnerable. Thus, boosting cholinergic neuronal function and survival has been a focus of the few drugs currently available for this disorder. Nerve growth factor (NGF) is the archetypical protein discovered in the 1960s that is able to both increase survival and functioning of cholinergic neurons. However, the blood-brain barrier does not allow penetration of this protein into the brain. A phase 1 clinical trial recently published in the journal Nature Medicine utilized a unique ex vivo gene therapy approach to deliver NGF directly to the basal forebrain of AD patients. Despite the need for further testing, their report illustrated a mild but significant therapeutic benefit of NGF for the treatment of AD and provided important data concerning the safety and efficacy of ex vivo gene therapy in humans.
|
2,336,773 |
Two PMS2 mutations in a Turcot syndrome family with small bowel cancers.
|
We report the clinicopathological, genetic, and immunohistochemical characterization of an atypical Turcot syndrome (TS) family with small bowel cancer. The tumor family history of a patient with cafè-au-lait spots (CALS) and early onset adenomas, duodenal cancer, and glioblastoma was positive for colonic adenoma (mother), jejunal (maternal grandfather), lung (father), and colorectal (paternal uncle) cancers. PMS2 genetic testing identified the nonsense 1951C>T (Q643X) and the missense 161C>T (S46I) mutations. PMS2 expression was absent in the proband's duodenal cancer with high microsatellite instability. The normal cells also displayed no PMS2 expression and some degree of instability. Our findings point out the association between PMS2 and TS, and support the hypothesis that patients with a few polyps, small bowel tumors with a very early onset, glioblastoma, and CALS should be considered as a variant of hereditary nonpolyposis colorectal cancer. A recessive model of inheritance caused by compound heterozygous mutations was consistent with the observed severe clinical phenotype and has important implications for predicting cancer risk in both the proband and his relatives.
|
2,336,774 |
Characterization of G6PD deficiency in southern Croatia: description of a new variant, G6PD Split.
|
Glucose-6-phosphate dehydrogenase (G6PD) deficiency protects from severe forms of malaria. It is interesting therefore to analyze the molecular basis underlying G6PD deficiency in regions such as the Mediterranean basin where malaria was present for a long time in history. Here we report on the genetic characterization of G6PD deficiency among inhabitants of one Mediterranean region-the Dalmatian region of south Croatia. We analyzed 24 unrelated G6PD-deficient male subjects. Molecular testing revealed several different mutations: G6PD Cosenza 9, G6PD Mediterranean 4, G6PD Seattle 3, G6PD Union 3, and G6PD Cassano 1. Furthermore, we have identified one novel G6PD variant that we named G6PD Split. This variant is caused by a nucleotide change 1442 C-->G leading to the amino acid substitution 481 Pro-->Arg and is characterized by moderate enzyme deficiency (class III variant). This study reveals a higher prevalence (37.5%) of the Cosenza mutation in the Dalmatian region than anywhere else previously investigated and overall shows the considerable molecular heterogeneity underlining G6PD deficiency that can be observed in Mediterranean populations.
|
2,336,775 |
The effect of polymorphisms in the enhancer of split gene complex on bristle number variation in a large wild-caught cohort of Drosophila melanogaster.
|
The Enhancer of split complex [E(spl)-C] in Drosophila encompasses a variety of functional elements controlling bristle patterning and on the basis of prior work is a strong candidate for harboring alleles having subtle effects on bristle number variation. Here we extend earlier studies identifying associations between complex phenotypes and polymorphisms segregating among inbred laboratory lines of Drosophila and test the influence of E(spl)-C on bristle number variation in a natural cohort. We describe results from an association mapping study using 203 polymorphisms spread throughout the E(spl)-C genotyped in 2000 wild-caught Drosophila melanogaster. Despite power to detect associations accounting for as little as 2% of segregating variation for bristle number, and saturating the region with single-nucleotide polymorphisms (SNPs), we identified no single SNP marker showing a significant (additive over loci) effect after correcting for multiple tests. Using a newly developed test we conservatively identify six regions of the E(spl)-C in which the insertion of transposable elements as a class contributes to variation in bristle number, apparently in a sex- or trait-limited fashion. Finally, we carry out all possible 20,503 two-way tests for epistasis and identify a slight excess of marginally significant interactions, although none survive multiple-testing correction. It may not be straightforward to extend the results of laboratory-based association studies to natural populations.
|
2,336,776 |
Mutations in the Drosophila orthologs of the F-actin capping protein alpha- and beta-subunits cause actin accumulation and subsequent retinal degeneration.
|
The progression of several human neurodegenerative diseases is characterized by the appearance of intracellular inclusions or cytoskeletal abnormalities. An important question is whether these abnormalities actually contribute to the degenerative process or whether they are merely manifestations of cells that are already destined for degeneration. We have conducted a large screen in Drosophila for mutations that alter the growth or differentiation of cells during eye development. We have used mitotic recombination to generate patches of homozygous mutant cells. In our entire screen, mutations in only two different loci, burned (bnd) and scorched (scrd), resulted in eyes in which the mutant patches appeared black and the mutant tissue appeared to have undergone degeneration. In larval imaginal discs, growth and cell fate specification occur normally in mutant cells, but there is an accumulation of F-actin. Mutant cells degenerate much later during the pupal phase of development. burned mutations are allelic to mutations in the previously described cpb locus that encodes the beta-subunit of the F-actin capping protein, while scorched mutations disrupt the gene encoding its alpha-subunit (cpa). The alpha/beta-heterodimer caps the barbed ends of an actin filament and restricts its growth. In its absence, cells progressively accumulate actin filaments and eventually die. A possible role for their human orthologs in neurodegenerative disease merits further investigation.
|
2,336,777 |
Keratins as susceptibility genes for end-stage liver disease.
|
<AbstractText Label="BACKGROUND & AIMS" NlmCategory="OBJECTIVE">Keratins 8 and 18 protect the liver from stress. Keratin 8 and 18 variants in 17 of 467 liver disease explants and 2 of 349 blood bank controls were previously reported in 5 analyzed exonic regions. We asked whether mutations were present in the remaining 10 exons of keratins 8 and 18.</AbstractText>Exonic regions were polymerase chain reaction-amplified from genomic DNA, isolated from the above-mentioned 2 cohorts, and analyzed for the presence of mutations. Mutant keratins were also studied biochemically.</AbstractText>We identified 10 novel keratin 8 and 18 heterozygous variants in 44 of 467 explants and 11 of 349 controls: keratin 18 deletion (delta64-71), a keratin 8 frameshift that truncates the last 14 amino acids; 8 missense keratin 8 and 18 alterations; and several new polymorphisms. The most common variant, keratin 8 R340H, at the highly conserved R340 was found in 30 of 467 explants and 10 of 349 controls (P = .02) and was confirmed in the diseased livers by generation of an R340H-specific antibody. Germline transmission and variant protein expression were verified. The mutations involved a variety of liver diseases, and some variants had an ethnic background preponderance. Mutations that introduced disulfide bonds (keratin 8 G61C or R453C) decreased keratin solubility, particularly after oxidative stress, whereas others decreased keratin 8 phosphorylation (keratin 8 G433S).</AbstractText>The overall frequency of keratin 8 and 18 variants was 12.4% in 467 liver disease explants and 3.7% in 349 blood bank controls (P < .0001). Variants can alter keratin solubility or phosphorylation and may render individuals susceptible to end-stage liver disease, depending on their genetic background and exposure to other insults, such as alcohol or viral infection.</AbstractText>
|
2,336,778 |
Characterization of hMLH1 and hMSH2 gene dosage alterations in Lynch syndrome patients.
|
<AbstractText Label="BACKGROUND & AIMS" NlmCategory="OBJECTIVE">A significant proportion of Lynch syndrome cases are believed to be due to large genomic alterations in the mismatch repair genes hMLH1 and hMSH2. However, previous studies have not adequately identified the frequency and scope of such mutations, and routine clinical Lynch syndrome testing often does not include analysis for these mutations. Our aim was to characterize hMLH1 and hMSH2 genomic rearrangements in a large population of suspected Lynch syndrome patients.</AbstractText>A total of 365 samples from probands referred for genetic testing for Lynch syndrome were analyzed for the presence of large genomic alterations in hMLH1 or hMSH2 by using a combination of techniques. Samples with a deletion in exons 1-6 in hMSH2 were further characterized by polymerase chain reaction to establish the presence of the hMSH2 American founder deletion.</AbstractText>An hMLH1 or hMSH2 mutation was identified in 153 cases, and, of these, 12 of 67 (17.9%) and 39 of 86 (45.3%) had a large genomic alteration in hMLH1 and hMSH2, respectively. Overall, 6 different hMLH1 and 12 different hMSH2 deletions/duplications, including 10 novel mutations, were identified. Analysis of the hMSH2 exon 1-6 deletion samples showed that 13 of 18 (72.2%) had the American founder deletion.</AbstractText>These data show a high frequency and diverse spectrum of large genomic alterations in hMLH1 and hMSH2 in suspected Lynch syndrome patients. Thus, a comprehensive mutation identification strategy that includes the ability to detect large genomic rearrangements is imperative for the clinical genetic identification of Lynch syndrome patients and families.</AbstractText>
|
2,336,779 |
[Familial Mediterranean fever among the autoimmune diseases].
|
During the first attacks of familial Mediterranean fever, each of the disease symptoms can suggest a series of disorders. When the disease is older, the recurrence of symptoms may simulate some systemic diseases, but mainly suggests familial Mediterranean fever, one of a group of hereditary autoinflammatory diseases. Before the gene for familial Mediterranean fever was identified, various sets of criteria were used for diagnosis. The presence of MEFV mutations confirms the diagnosis, but the clinical criteria still determine who should undergo this genetic testing. The genotype-phenotype correlations add a prognostic dimension to the mutations identified. Genotyping can also lead to the diagnosis of the other autoinflammatory diseases, which constitute the basis of the differential diagnosis of familial Mediterranean fever. The hyperimmunoglobulinemia D syndrome (HIDS) is very similar to familial Mediterranean fever in its recessive transmission and abdominal and articular symptoms. It can be distinguished by the European origin of the patients, the presence of cervical lymph nodes and the increased IgD levels. Of the diseases with dominant transmission, the TNF receptor-associated periodic syndromes (TRAPS) are suggested by periorbital edema and migrating inflammatory cellulitis. Muckle and Wells syndrome is revealed by episodes of fever with urticaria and arthralgia, complicated by deafness and amyloidosis. Mutations in the same gene are responsible for two disorders, both appearing in childhood: familial cold urticaria syndrome (FCUS) and chronic infantile neurocutaneous articular syndrome (CINC). The pathogenesis of familial Mediterranean fever is still unclear. Pyrin/marenostrin, the protein produced by the MEFV gene, appears to hae a physiological antiinflammatory effect that inhibits proinflammatory cytokines. Mutation of the gene may eliminate this feedback mechanism and expose the patient to flares from any inflammatory stimulus, even minimal. Amyloid is produced by the serum amyloid A protein (SAA), and its occurrence is influenced by the type of MEFV mutation, but also the genotype of the gene producing SAA.
|
2,336,780 |
Early environmental origins of neurodegenerative disease in later life.
|
Parkinson disease (PD) and Alzheimer disease (AD), the two most common neurodegenerative disorders in American adults, are of purely genetic origin in a minority of cases and appear in most instances to arise through interactions among genetic and environmental factors. In this article we hypothesize that environmental exposures in early life may be of particular etiologic importance and review evidence for the early environmental origins of neurodegeneration. For PD the first recognized environmental cause, MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine), was identified in epidemiologic studies of drug abusers. Chemicals experimentally linked to PD include the insecticide rotenone and the herbicides paraquat and maneb; interaction has been observed between paraquat and maneb. In epidemiologic studies, manganese has been linked to parkinsonism. In dementia, lead is associated with increased risk in chronically exposed workers. Exposures of children in early life to lead, polychlorinated biphenyls, and methylmercury have been followed by persistent decrements in intelligence that may presage dementia. To discover new environmental causes of AD and PD, and to characterize relevant gene-environment interactions, we recommend that a large, prospective genetic and epidemiologic study be undertaken that will follow thousands of children from conception (or before) to old age. Additional approaches to etiologic discovery include establishing incidence registries for AD and PD, conducting targeted investigations in high-risk populations, and improving testing of the potential neurologic toxicity of chemicals.
|
2,336,781 |
Rational design of a plasmid DNA vaccine capable of eliciting cell-mediated immune responses to multiple HIV antigens in mice.
|
Given the importance of the HIV-specific cell-mediated immune response in the early control and resolution of HIV infection and the observed correlation between pre-challenge vaccine elicited CTL responses and post challenge outcome in SHIV/rhesus macaque experiments, we sought to identify several candidate plasmid DNA (pDNA) vaccine designs capable of eliciting robust and balanced cell-mediated immune responses to multiple HIV-1 derived antigens in mice for further vaccine development. To rationally construct candidate vaccines for immunogenicity testing, we determined the relative immunogenicity of the individual HIV-derived vaccine antigens (env, gag, pol, nef, tat and vif) and the relative strength of various transcriptional control elements (HCMV, SCMV, HSV Lap1) in Balb/c mice. Next, a number of 1-, 2-, 3- and 4-vector pDNA vaccine designs were tested for their ability to elicit HIV-1 antigen-specific CMI responses. For these studies, Balb/c mice were immunized with a fixed total pDNA vaccine dose of 100 mcg in combination with 25 mcg plasmid-based murine IL-12 and tested for the induction of HIV-1 antigen-specific CMI responses by IFN-gamma ELISpot analysis. The results of this study indicate that all pDNA vaccine designs were capable of eliciting CMI responses to multiple HIV-1 antigens. As a result of this iterative comparative analysis, we have identified a number of pDNA vaccine candidates capable of eliciting potent, balanced CMI responses to multiple HIV-1 derived antigens. These results have important implications for the design and development of an efficacious vaccine for the prevention of HIV-1 infection.
|
2,336,782 |
Semi-synthetic mammalian gene regulatory networks.
|
In recent years gene network engineers have celebrated spectacular success: Genetic devices such as epigenetic toggle switches and oscillating networks have been engineered and pioneered a new ever-increasing scientific community known as synthetic biology. While synthetic biology was until recently restricted to network assembly and testing in prokaryotes, decisive advances have been achieved in eukaryotic systems based on current availability of different human-compatible transgene control technologies. Most prominent examples include the epigenetic gene network enabling metastable fully inheritable transgene expression states in mice, artificial regulatory cascades managing multi-level expression control and Boolean-type BioLogic gates supporting near-digital expression readout. The majority of transgene control networks available to date are fully synthetic and integrate artificial extracellular signals in a desired host metabolism-independent manner. Yet, in order to develop their full anticipated therapeutic potential, synthetic transgene control circuits need to be well interconnected with the host cell's regulatory networks in order to enable physiologic control of prosthetic molecular expression units. We have designed three semi-synthetic transcription control networks able to integrate physiologic oxygen levels and artificial antibiotic signals to produce expression readout with NOT IF or NOR-type Boolean logic or discrete multi-level control of several intracellular and secreted model product proteins. Subtle differences in the regulation performance of the endogenous oxygen-sensing system in CHO-K1 and human HT-1080 switched the semi-synthetic network's readout from a classic four-level (high, medium, low, basal) regulatory cascade to a network enabling six discrete transgene expression levels. These findings are in excellent correspondence with a mathematical model. Prosthetic networks, precisely embedded in host regulatory networks and co-fine-tuned by physiologic as well as pharmacologic input signals, will foster future advances in gene therapy and tissue engineering.
|
2,336,783 |
Telomerase-immortalized human fibroblasts retain UV-induced mutagenesis and p53-mediated DNA damage responses.
|
Immortalized cells frequently have disruptions of p53 activity and lack p53-dependent nucleotide excision repair (NER). We hypothesized that telomerase immortalization would not alter p53-mediated ultraviolet light (UV)-induced DNA damage responses. DNA repair proficient primary diploid human fibroblasts (GM00024) were immortalized by transduction with a telomerase expressing retrovirus. Empty retrovirus transduced cells senesced after a few doublings. Telomerase transduced GM00024 cells (tGM24) were cultured continuously for 6 months (>60 doublings). Colony forming ability after UV irradiation was dose-dependent between 0 and 20J/m2 UVC (LD50=5.6J/m2). p53 accumulation was UV dose- and time-dependent as was induction of p48(XPE/DDB2), p21(CIP1/WAF1), and phosphorylation on p53-S15. UV dose-dependent apoptosis was measured by nuclear condensation. UV exposure induced UV-damaged DNA binding as monitored by electrophoretic mobility shift assays using UV irradiated radiolabeled DNA probe was inhibited by p53-specific siRNA transfection. p53-Specific siRNA transfection also prevented UV induction of p48 and improved UV survival measured by colony forming ability. Strand-specific NER of cyclobutane pyrimidine dimers (CPD) within DHFR was identical in tGM24 and GM00024 cells. CPD removal from the transcribed strand was nearly complete in 6h and from the non-transcribed strand was 73% complete in 24h. UV-induced HPRT mutagenesis in tGM24 was indistinguishable from primary human fibroblasts. These wide-ranging findings indicate that the UV-induced DNA damage response remains intact in telomerase-immortalized cells. Furthermore, telomerase immortalization provides permanent cell lines for testing the immediate impact on NER and mutagenesis of selective genetic manipulation without propagation to establish mutant lines.
|
2,336,784 |
Risk of breast cancer recurrence and contralateral breast cancer in relation to BRCA1 and BRCA2 mutation status following breast-conserving surgery and radiotherapy.
|
BRCA1 and BRCA2 germline mutations are associated with a strong risk of breast cancer, which may preclude breast-conserving treatment in carriers. This study examined whether mutation status influenced the rate of breast cancer recurrence following breast-conserving treatment. BRCA1 and BRCA2 genes were screened for germline mutations in 131 patients with a family history of breast and/or ovarian cancer, who had been treated with breast-conserving surgery and radiotherapy. The 131 patients with familial history were matched to 261 patients without, according to age at diagnosis and year of treatment. The follow-up of controls was at least equal to the time-interval between diagnosis and genetic testing in familial cases. Matched cohorts were compared according to rates of breast cancer recurrence as first event and contralateral breast cancer using log-rank tests. BRCA1/2 mutations were found in 20.6% patients with a family history. Nineteen patients had a BRCA1 mutation and 8 had a BRCA2 mutation. Breast cancers in mutation carriers were more often grade III (p<10-4) and oestrogen receptor negative (p=0.005) than tumours in both non-carriers and controls. Median follow-up for all 392 patients was 8.75 years. No significant differences in breast cancer recurrence as first event were seen between BRCA1/2 tumours and controls (p=0.47), carriers and non-carriers with a family history (p=0.96), or non-carriers and controls (p=0.10). On multivariate analysis, age was the most important factor significantly predicting for breast cancer recurrence. The rate of contralateral breast cancer was significantly increased in all patients with a family history: BRCA1/2 carriers versus controls (p=0.0003), non-carriers versus controls (p=0.0034) and carriers versus non-carriers (p=0.02). At a 9-year median follow-up, the rate of ipsilateral breast cancer recurrence was not higher in BRCA1 and BRCA2 mutation carriers than in non-carriers with a family history or sporadic cases. These results support the hypothesis that breast tumours in BRCA carriers are more sensitive to radiation. Therefore, breast-conserving treatment can be offered to these patients. However, longer follow-up is needed to ensure that the rate of new primary cancer in the treated breast does not increase in the long-term.
|
2,336,785 |
[Extending preimplantation genetic diagnosis to HLA typing: the Paris experience].
|
Preimplantation genetic diagnosis (PGD) consists in the genetic analysis of one or two cells. These cells (blastomeres) are sampled from embryos, obtained by in vitro fertilization, at the third day of development. Since 1998, the bioethical laws (1994) and their decrees restricted PGD practices in France, strictly to the avoidance of the birth of a child affected with a genetic defect. In parallel, works on blood cord transplantation, taken at the birth of a compatible HLA sibling, showed very encouraging results, particularly for the treatment of Fanconi anemia. In 2001, Verlinsky et al., have reported the first PGD for Fanconi anaemia combined with HLA typing, allowing the birth of a healthy child, HLA-identical with his affected sister. The "designer baby" concept was born. The French law, which allowed PGD under specific conditions, i.e. when the genetic defect has been characterized in one parent at least, recently extended PGD to HLA typing when embryos are at risk of a genetic disorder. Article L.2131-4-1 (August 2004) allows the practice of HLA typing for PGD embryos when an elder sibling is affected with a genetic disorder and need stem cell transplantation. The HLA-matched offspring resulting from PGD can give cord blood at birth to supply the necessary therapy. This double selection give rise to serious ethical problems, but technical difficulties and legal restrictions will probably limit the development of such a procedure.
|
2,336,786 |
["Designer baby" changed to French for "double hope baby"].
|
Scientific advances during the last decades regarding potential intervention on embryos arouse many questions in society to prepare the ground concerning the limits that should be set for these practices. For the first time in 1994, a parliamentary proceeding allowed the definition of a French model of bioethics through laws of the same name. These laws, among others, authorized in a well and strictly defined setting the practice of preimplantation genetic diagnosis (PGD). Because of technical progress concerning PGD, new questions arose, especially concerning the accomplishment of designer babies. The French Chamber of Representatives came in with a new law that banishes the concept of designer babies and replaces it with another concept: double hope babies, in French "bébé du double espoir". A first hope of a pregnancy giving birth to a healthy child and the second being that this child conceived with the aid of PGD could help treat an elder brother. Because of the issuing of two specific laws in a ten years interval, France occupies a privileged place in a Europe where bioethical issues continue to be debated, particularly PGD.
|
2,336,787 |
[Preimplantation genetic diagnosis in order to choose a saviour sibling].
|
Preimplantation genetic diagnosis with HLA matching in order to bring about the birth of a saviour sibling is not mere instrumentalisation of the future child, as long as the post natal test is used and the future child will be looked after with the same love and care as if he/she had not been selected as well for the purpose.
|
2,336,788 |
No association between monoamine oxidase A promoter polymorphism and personality traits in Japanese females.
|
Monoamine oxidase A (MAO-A) is an enzyme involved in the metabolism of monoamine neurotransmitters such as dopamine, serotonin, and noradrenaline in the brain. Previous studies have demonstrated a significant association between MAO-A gene polymorphism and personality traits in males. The purpose of the present study was to examine this association in females. The subjects were 219 healthy Japanese females. We genotyped a variable number of tandem repeats located upstream of the MAO-A gene. Personality traits were assessed using the Temperament and Character Inventory (TCI). There was no association between any personality trait and MAO-A genotype. The present results do not support the hypothesis that MAO-A gene polymorphism is related to certain personality traits in females.
|
2,336,789 |
Progress towards an HIV-1 subtype C vaccine.
|
Several scientific fields related to vaccine development have made significant advances in understanding how to design immunogens against selected infectious pathogens. In the case of human immunodeficiency virus type-1 (HIV-1), anti-retroviral (ARV) drugs have dramatically improved the health and extended the lives of people with HIV/AIDS. However, their high cost of implementation and demanding clinical requirements put them out of reach of the vast majority of people with HIV, especially in developing countries where HIV infection levels are high and public resources are extremely scarce. With 25.4 million people living with HIV/AIDS in sub-Saharan Africa as of the end of 2004 (http://www.unaids.org), this region was still by far the worst-affected in the world with HIV-1 subtype C (HIV-1C) accounting for the majority of infections. Although the constraints placed by HIV genetic variation on vaccine efficacy remain unclear, there is an indication that they may be important and several candidate vaccines targeting HIV-1C are currently under investigation in both pre-clinical and clinical settings. The designs of these candidate HIV-1C vaccines focus on both regulatory and structural HIV-1 proteins derived from HIV-1C. They make use of a number of current vaccine technologies for their delivery to invoke adaptive immune responses in individuals that hopefully may prove to be protective. This review looks at the progress and accomplishments made thus far in the generation and testing of such HIV-1C vaccines.
|
2,336,790 |
Biochemical and cytochemical evaluation of heterozygote individuals with glucose-6-phosphate dehydrogenase deficiency.
|
The aim of this study was to diagnose heterozygous glucose-6-phosphate dehydrogenase (G6PD) deficient females by an inexpensive cytochemical G6PD staining method that is easy to perform, allowing diagnosis of G6PD deficiency without cumbersome genetic analysis. Three subject groups were included in the study. The first group consisted of 15 hemizygous deficient males. The second and the third group were composed of 15 heterozygous deficient females and 15 healthy individuals, respectively. Biochemical determination and cytochemical staining of G6PD activity were performed in samples of all subjects. Results obtained with the cytochemical staining method correlated significantly with the biochemical data (p < 0.001), but a only 51-68% of the erythrocytes were stained positively in females with normal biochemical G6PD activity despite their having a G6PD-deficient child. This observation clearly indicates that these individuals are heterozygously deficient. These findings show that the cytochemical staining method to detect G6PD activity in erythrocytes is reliable, sensitive and specific and is superior to the biochemical method. Therefore, this method can be used routinely to detect heterozygous G6PD deficiency.
|
2,336,791 |
The T-box transcription factor SEA-1 is an autosomal element of the X:A signal that determines C. elegans sex.
|
Sex is determined in C. elegans by a chromosome-counting mechanism that tallies X chromosome dose relative to the sets of autosomes, the X:A ratio. A group of genes on X called X signal elements (XSEs) communicates X chromosome number by repressing the activity of the master sex-determination switch gene xol-1 in a dose-dependent manner. xol-1 is repressed by transcriptional and posttranscriptional mechanisms and is inactive in XX animals (hermaphrodite) but active in XO animals (male). Prior to our work, the nature of the autosomal signal and its target(s) were unknown. Here we show the signal includes discrete, trans-acting autosomal signal elements (ASEs) that counter XSEs to coordinately control both sex determination and dosage compensation. sea-1, the first autosomal signal element, encodes a T-box transcription factor that opposes XSEs by activating transcription of xol-1. Hence, xol-1 integrates both X and autosomal signals to determine sexual fate.
|
2,336,792 |
["Jaw drop" as an atypical manifestation of Kennedy's disease].
|
Kennedy's disease, or spinal and bulbar muscular atrophy (SBMA), is an inherited X-linked degenerative disorder characterised by slowly progressive proximal limb weakness, bulbar weakness, fasciculations, signs of androgen insensitivity and characteristic EMG findings. The disease is caused by a trinucleotide (CAG) repeat in the androgen receptor gene. We describe a patient with atypical symptoms who was initially misdiagnosed after presenting with weakness of mm. masseter and mm. temporales that caused his jaw to hang open. The initial diagnosis was suspicion of myasthenia gravis or ALS. Genetic testing later confirmed the diagnosis of Kennedy's disease.
|
2,336,793 |
A comparison of case-control and family-based association methods: the example of sickle-cell and malaria.
|
There has been much debate about the relative merits of population- and family-based strategies for testing genetic association, yet there is little empirical data that directly compare the two approaches. Here we compare case-control and transmission/disequilibrium test (TDT) study designs using a well-established genetic association, the protective effect of the sickle-cell trait against severe malaria. We find that the two methods give similar estimates of the level of protection (case-control odds ratio = 0.10, 95% confidence interval 0.03-0.23; family-based estimate of the odds ratio = 0.11, 95% confidence interval 0.04-0.25) and similar statistical significance of the result (case-control: chi2= 41.26, p= 10(-10), TDT: chi2= 39.06, p= 10(-10)) when 315 TDT cases are compared to 583 controls. We propose a family plus population control study design, which allows both case-control and TDT analysis of the cases. This combination is robust against the respective weaknesses of the case-control and TDT study designs, namely population structure and segregation distortion. The combined study design is especially cost-effective when cases are difficult to ascertain and, when the case-control and TDT results agree, offers greater confidence in the result.
|
2,336,794 |
Molecular diagnosis of inherited disorders: lessons from hemoglobinopathies.
|
Hemoglobinopathies constitute a major health problem worldwide, with a high carrier frequency, particularly in certain regions where malaria has been endemic. These disorders are characterized by a vast clinical and hematological phenotypic heterogeneity. Over 1,200 different genetic alterations that affect the DNA sequence of the human alpha-like (HBZ, HBA2, HBA1, and HBQ1) and beta-like (HBE1, HBG2, HBG1, HBD, and HBB) globin genes are mainly responsible for the observed clinical heterogeneity. These mutations, together with detailed information about the resulting phenotype, are documented in the globin locus-specific HbVar database. Family studies and comprehensive hematological analyses provide useful insights for accurately diagnosing thalassemia at the DNA level. For this purpose, numerous techniques can provide accurate, rapid, and cost-effective identification of the underlying genetic defect in affected individuals. The aim of this article is to review the diverse methodological and technical platforms available for the molecular diagnosis of inherited disorders, using thalassemia and hemoglobinopathies as a model. This article also attempts to shed light on issues closely related to thalassemia diagnostics, such as prenatal and preimplantation genetic diagnoses and genetic counseling, for better-quality disease management.
|
2,336,795 |
Do-it-yourself diagnosis.
|
Despite apprehension and controversy, direct-to-consumer genetic tests are becoming more popular
|
2,336,796 |
We can change the future.
|
Is genetic testing a powerful tool for determining the health prospects of our children?
|
2,336,797 |
Auditory deficits associated with the frings mgr1 (mass1) mutation in mice.
|
The gene responsible for the audiogenic seizure (AGS) phenotype in Frings mice, which was identified and originally designated Mass1, is now referred to as Mgr1. Although the function of the gene product is not known, the expression pattern suggests a role in the developing CNS. Hearing impairment is often observed in AGS-susceptible rodents and is thought to contribute to the pathology of AGS. We therefore hypothesized that the Frings mouse exhibits early-onset hearing impairment and that the Frings Mgr1 mutation is responsible for the hearing impairment phenotype that leads to the development of AGS susceptibility. Auditory brainstem response (ABR) thresholds were used to evaluate auditory function in mice carrying the Frings Mgr1 allele and were compared with other AGS-susceptible and -resistant mice. ABR testing demonstrated that mice possessing the Frings Mgr1 allele exhibit a mild to moderate level of hearing impairment that is present during the days following hearing onset. Furthermore, the hearing impairment resulting from the Frings Mgr1 allele is relatively stable, which explains the long duration of AGS susceptibility exhibited by Frings mice compared with other AGS-susceptible mice.
|
2,336,798 |
Functional genomics analysis of foliar condensed tannin and phenolic glycoside regulation in natural cottonwood hybrids.
|
Regulation of leaf condensed tannins (CT) and salicylate-derived phenolic glycosides (PG) in fast- and slow-growing cottonwood backcrosses was analyzed by metabolic profiling and cDNA microarray hybridization. Seven hybrid lines of Populus fremontii L. and P. angustifolia James exhibiting growth/CT-PG phenotypes ranging from fast/low (Lines 18 and 1979) to slow/high (Lines 1012 and RL2) and intermediate (Lines NUL, 3200 and RM5) were investigated. Methanol-extractable leaf metabolites were analyzed by gas chromatography-mass spectrometry, and the results evaluated by principal component analysis. The hybrid lines formed separate clusters based on their primary metabolite profiles, with cluster arrangement also reflecting differences in CT-PG phenotype. Nitrogen (N) supply was manipulated to alter CT-PG partitioning and to obtain molecular insights into how primary metabolism interfaces with CT-PG accumulation. Three backcross lines (RM5, 1012, 18) exhibiting differential CT-PG responses to a 10-day hydroponic N-deprivation treatment were chosen for metabolite and gene expression analyses. The fast- growing Line 18 showed a minimal CT-PG response to N deprivation, and a reduction in photosynthetic gene expression. Line 1012 exhibited a strong phenylpropanoid response to N deprivation, including a doubling in phenylalanine ammonia-lyase (PAL) gene expression, and a shift from CT accumulation in the absence of stress toward PG accumulation under N-deprivation conditions. Amino acid concentrations were depressed in Lines 18 and 1012, as was expression of nitrate-sensitive genes coding for transketolase (TK), and malate dehydrogenase (MDH). Genes associated with protein synthesis and fate were down-regulated in Line 1012 but not in Line 18. Line RM5 exhibited a comparatively large increase in CT in response to N deprivation, but did not sustain decreases in amino acid concentrations, or changes in PAL, TK or MDH gene expression. Molecular characterization of the variable CT-PG responses shows promise for the identification and future testing of candidate genes for CT-PG trait selection or manipulation.
|
2,336,799 |
Sec15, a component of the exocyst, promotes notch signaling during the asymmetric division of Drosophila sensory organ precursors.
|
Asymmetric division of sensory organ precursors (SOPs) in Drosophila generates different cell types of the mature sensory organ. In a genetic screen designed to identify novel players in this process, we have isolated a mutation in Drosophila sec15, which encodes a component of the exocyst, an evolutionarily conserved complex implicated in intracellular vesicle transport. sec15(-) sensory organs contain extra neurons at the expense of support cells, a phenotype consistent with loss of Notch signaling. A vesicular compartment containing Notch, Sanpodo, and endocytosed Delta accumulates in basal areas of mutant SOPs. Based on the dynamic traffic of Sec15, its colocalization with the recycling endosomal marker Rab11, and the aberrant distribution of Rab11 in sec15 clones, we propose that a defect in Delta recycling causes cell fate transformation in sec15(-) sensory lineages. Our data indicate that Sec15 mediates a specific vesicle trafficking event to ensure proper neuronal fate specification in Drosophila.
|
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.