The Full Genomic Sequence of the HLA-A*02:332 Allele Identified Using PacBio Sequencing.
We report the full genomic sequence of the HLA-A*02:332 allele.
Alleles↗
Biomedical subjects
Jianfang Chen
Publications and source records attributed to Jianfang Chen.
Toward synthesis of the regular sequence of heparin: synthesis of two tetrasaccharide precursors.
Two fully protected tetrasaccharides, which represent precursors for the synthesis of the regular sequence of heparin, were synthesized via coupling of a pair of disaccharide trichloroacetimidates with a thioglycoside and a glucosamine derivative, respectively, in a sequential manner.
Acetamides↗
Assessing BRCA carrier probabilities in extended families.
PURPOSE: Carrier prediction models estimate the probability that a person has a BRCA mutation. We evaluated the accuracy of the BOADICEA model and compared its performance with that of other models (BRCAPRO, Myriad I and II, Couch, and Manchester Scoring System). We also studied the effect of extended family information on risk estimation using BOADICEA. METHODS: We compared the area under receiver operating characteristic curves generated from 472 families with one member tested for BRCA mutations. We calculated sensitivity, specificity, and predictive values at an estimated probability of 10% and explored the biases of carrier prediction. RESULTS: BOADICEA performed better than the other models in Ashkenazi Jewish (AJ) families, BRCAPRO performed slightly better in non-AJ families, and Myriad II performed comparably well in both groups. Including extended family information in BOADICEA yielded slightly better performance than did limiting the information to second-degree relatives. Using a 10% cutoff point, BOADICEA and Myriad II were most sensitive in predicting BRCA1/2 mutations in AJ families, and Myriad II was most sensitive in non-AJ families. The Manchester Scoring System was the most sensitive and least specific in a subgroup of non-AJ families. BOADICEA and BRCAPRO tended to underestimate the observed risk at low estimated probabilities and overestimate it at higher probabilities. CONCLUSION: The BOADICEA, BRCAPRO, and Myriad II models performed similarly. Including second-degree relatives slightly improved carrier prediction by BOADICEA. The Myriad II model was the easiest to implement.
Adult↗
Two-color two-photon 4Pi fluorescence microscopy.
In 4Pi fluorescence microscopy the point-spread function is composed of a strong central lobe accompanied by interference sidelobes that produce artifacts in the image. We propose to combine two-color two-photon fluorescence microscopy and 4Pi fluorescence microscopy to overcome this sidelobe problem. Simulation results show that a single sharp fluorescence spot can be produced by use of two excitation wavelengths of 400 and 800 nm and detected at 350-nm emission wavelength.
Equipment Design↗
Effect of winsorization on power and type 1 error of variance components and related methods of QTL detection.
Variance components analysis provides an efficient method for performing linkage analysis for quantitative traits. However, power and type 1 error of variance components-based likelihood ratio testing may be affected when phenotypic data are nonnormally distributed (especially with high values of kurtosis) and there is moderate to high correlation among the siblings. Winsorization can reduce the effect of outliers on statistical analyses. Here, we considered the effect of winsorization on variance components-based tests. We considered the likelihood ratio test (LRT), the Wald test, and some robust variance components tests. We compared these tests with Haseman-Elston least squares-based tests. We found that power to detect linkage is significantly increased after winsorization of the nonnormal phenotypes. Winsorization does not greatly diminish the type 1 error for the variance components-based tests for markedly nonnormal data. A robust version of the LRT that adjusts for sample kurtosis showed the best power for nonnormal data. Finally, phenotype winsorization of nonnormal data reduces the bias in estimation of the major gene variance component.
Alleles↗
Carbon nanotubes as separation carrier in capillary electrophoresis.
The utility and versatility of carboxylic single-walled carbon nanotubes (c-SWNT) in capillary electrophoresis (CE) is demonstrated, using as model solutes homologues and structural isomers. In the case of homologues of caffeine and theobromine, distinct changes in the electrophoretic parameters occur at a critical concentration of c-SWNT in the run buffer. It is suggested that the c-SWNT of a definite concentration could form a network in the run buffer as a pseudostationary phase on the basis of the unique tubule structure, providing a different separation from sodium dodecyl sulfate (SDS) micelles. In the case of structural isomers of catechol and hydroquinone, differing from the homologues, it is mainly attributable to the functional groups on the c-SWNT that have an effect on the electrophoretic behaviors by forming intermolecular hydrogen bonding with analytes. Furthermore, aggregated c-SWNT serve as anticonvective media and minimize solute diffusion contributing to zone broadening. The presence of charged c-SWNT suppressed the electrodiffusion and decreased the adsorption between capillary wall and solutes, which led to better peak shapes of isomers.
Caffeine↗
Positional identification of microdeletions with genetic markers.
The positional identification of genetic factors for both simple and complex diseases is difficult. There is increasing evidence that small deletions are a fairly common cause for many genetic diseases and some complex diseases. To date, no statistical basis has been available for the identification of microdeletions in family studies. Here, we present an approach to the identification of novel microdeletions for parent-affected offspring trios. We present several different approaches that can be applied to identify microdeletions and also evaluate the statistical behavior of one of these methods in simulated data. The results show that for the study of single nucleotide polymorphisms, the error rate has an approximately linear effect in decreasing the ability to identify microdeletions. On the other hand, heterogeneity of causation, with only some families showing a microdeletion had a more severe influence upon the ability to identify de novo microdeletions.
Chromosome Mapping↗
[Association of antipsychotic agent-induced weight gain with a polymorphism of the promotor region of the 5-HT2C receptor gene].
OBJECTIVE: To determine whether 5-hydroxytryptamine 2C (5-HT2C) receptor gene 759C/T polymorphism influences the weight gain following antipsychotic agents (APS) treatment in patient with schizophrenia. METHODS: DNA was extracted from the peripheral blood of 117 Chinese first-episode patients of Han nationality with schizophrenia diagnosed according to CCMD-II-R criteria. PCR-RELP technique was used to analyse the frequencies of 5-HTR2C receptor gene 759C/T hemizygote (male) and genotype (female). Monotherapy with APS (chlorpromazine or rispperidone) was given for 10 weeks. The body weight was taken and body mass index (BMI) was calculated on admission and every week subsequently for each patient. The correlation of hemizygote or genotype and the BMI was analyzed. RESULTS: Ten weeks after treatment, there was an average increase in body weight of (3.2 +/- 3.5) kg or (5.7 +/- 6.2)% of the baseline weight with a range of -7 kg approximately 12 kg or -7.8% approximately 32%. The frequency of mutant hemizygote was 58% among the 58 male subjects; the frequency of mutant homozygote was 0%, and the frequency of mutant heterozygote was 27.0% among the 59 female subjects. The body weight gain > 7% occurred in 53% of wild type hemizygote males and 47% of wild type homozygote females; and only 18% of mutant hemizygote males and 13% of mutant heterozygote females. The proportions of 759T hemizygote males or heterozygote females in those with body weight gain > 7% and those with body weight < 7% were significantly different (chi(2) = 22.35, v1, P = 0.000 1; chi(2) = 12.36, v1, P = 0.000 1). Patients without mutant allele were five to six times more likely to develop substantial weight gain (OR = 5.11, 6.68). CONCLUSION: The 5-HT2C-receptor gene -759C/T polymorphism is associated with APS-induced weight gain. 759C-->T may be a protective factor for the development of weight gain in Chinese schizophrenic patients of Han nationality.
Adolescent↗