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Y B Li

Publications and source records attributed to Y B Li.

At least 55 records · Page 3Linked to original sources
PubMed2001

Further characterization and population data for the pentanucleotide STR polymorphism D10S2325.

Pentanucleotide tandem repeat markers are interesting for forensic sciences, because they may present less stutter on the electrophoretic pattern. We focused on the analysis of the DNA sequence for each allele at the pentanucleotide STR locus D10S2325 in order to understand their structures in the human genome and to construct human allelic ladder, which is necessary for forensic DNA typing. In order to evaluate the forensic applicability of D10S2325 and to construct a preliminary database, the genotype distributions and allele frequencies in three major ethnic groups were investigated. The population samples included Caucasians (Germans), Africans (African Americans), and Asians (Chinese). A total of 520 samples from unrelated individuals was analyzed by Amp-FLP. An example of each allele and new alleles were sequenced. Allele determination was carried out by comparison with a sequenced human allelic ladder made in-house. This pentanucleotide STR provided easily interpretable results. A total of 15 alleles was found in our population samples. Three new alleles were observed and named as alleles 19 and 21 based on the number of repeat motifs, while allele 19 can be divided further into two alleles, 19a and 19 according to analysis of the sequence. No evidence of deviation from Hardy-Weinberg equilibrium was observed. In 64 confirmed father/mother/child triplets no mutation event was observed. Using a maximum likelihood method, the mutation rate was indirectly estimated as 2.5 x 10(-5). These results suggest that D10S2325 is a useful marker for forensic casework and paternity analysis.

Black or African American↗
PubMed2001

Allele sequences of six new Y-STR loci and haplotypes in the Chinese Han population.

Human chromosome Y-specific short tandem repeat (Y-specific STR) markers have useful properties for forensic applications. However, there is a need to develop more Y-specific STR markers, because the discriminating power of each STR locus is limited. In the present study, we describe our results on six new Y-specific STR markers that were initially located using sequence database information by Ayub et al. and were named DYS434, DYS435, DYS436, DYS437, DYS438 and DYS439. Our studies focused on the analysis of the DNA sequence for each allele at all six Y-specific STR loci in order to understand their structures in the human genome and to construct human allelic ladders, which are necessary for forensic DNA typing. In addition, the haplotype distribution for all six analyzed loci was studied in a Chinese Han population sample. The results indicate that DYS434, DYS435, DYS436, DYS437, DYS438 and DYS439 are useful Y-specific STR markers for forensic sciences.

Alleles↗
PubMed2001

[Resolution of overlapping chromatographic peaks by radial basis function neural network].

A new algorithm-resolution of overlapping chromatographic peaks by radial basis function neural network(RBFNN) is presented. A two-phase genetic algorithm(GA) which has robustness and random globe optimization is used to train RBFNN so that it has the ability on the resolution of overlapping chromatographic peaks. The two-phase genetic algorithm involves two procedures: training structure and optimizing parameter. The first procedure uses GA to train the architectures of RBFNN, the second procedure uses gradient descent to train the center(tR) and the width(sigma) of RBFNN. The alternate use of these two procedures makes the network having the ability to learn structure, therefore makes itself adaptable to resolution of the chromatographic peaks with unknown number of components. The method proposed here needs no artificial interference, not only has it robustness and globalism, but also the ability of accurate resolution to completely overlapped chromatographic peaks. The simulation experiments show that this method is more accurate than other methods.

Algorithms↗
PubMed2000

Gene expression profiling in the human hypothalamus-pituitary-adrenal axis and full-length cDNA cloning.

The primary neuroendocrine interface, hypothalamus and pituitary, together with adrenals, constitute the major axis responsible for the maintenance of homeostasis and the response to the perturbations in the environment. The gene expression profiling in the human hypothalamus-pituitary-adrenal axis was catalogued by generating a large amount of expressed sequence tags (ESTs), followed by bioinformatics analysis (http://www.chgc.sh.cn/ database). Totally, 25,973 sequences of good quality were obtained from 31,130 clones (83.4%) from cDNA libraries of the hypothalamus, pituitary, and adrenal glands. After eliminating 5,347 sequences corresponding to repetitive elements and mtDNA, 20,626 ESTs could be assembled into 9, 175 clusters (3,979, 3,074, and 4,116 clusters in hypothalamus, pituitary, and adrenal glands, respectively) when overlapping ESTs were integrated. Of these clusters, 2,777 (30.3%) corresponded to known genes, 4,165 (44.8%) to dbESTs, and 2,233 (24.3%) to novel ESTs. The gene expression profiles reflected well the functional characteristics of the three levels in the hypothalamus-pituitary-adrenal axis, because most of the 20 genes with highest expression showed statistical difference in terms of tissue distribution, including a group of tissue-specific functional markers. Meanwhile, some findings were made with regard to the physiology of the axis, and 200 full-length cDNAs of novel genes were cloned and sequenced. All of these data may contribute to the understanding of the neuroendocrine regulation of human life.

Alternative Splicing↗
PubMed2000

[Determination of aflatoxins in peanut by high performance liquid chromatography using immunoaffinity column clean-up and on-line electrochemical derivatization].

A method for the determination of aflatoxin B1, B2, G1 and G2 in peanut by high performance liquid chromatography using immunoaffinity column clean-up and on-line electrochemical derivatization was developed. Sample was extracted with 80% methanol and the extract was passed through the IAC. Aflatoxins were retained by the monoclonal in the IAC and eluted with actonitrile. AFT B1 and G1 were derivatized with on-line electrochemical equipment Kobra Cell. The four toxins can be separated in 13 minutes and the detection limit was 0.1 microgram/kg for each toxin. The method has been applied to the determination of peanut sample. The relative standard deviation was 9.2%-15% and the average recovery of AFT spiked at 0.5-9.0 micrograms/kg levels was in the range of 74.8%-97.3%.

Aflatoxin B1↗
PubMed1999

D20S161 data for three ethnic populations and forensic validation.

In order to evaluate the forensic applicability of the STR locus D20S161 and construct a preliminary database, the genotype distributions and allele frequencies in five populations from three main ethnic groups were investigated, including Germans, Slovakians, African Americans, Japanese and Chinese. A total of 512 samples from unrelated individuals and 85 confirmed father/mother/ child triplets were analyzed by PCR and allele determination was carried out by comparison with a sequenced human allelic ladder. The results showed that D20S161 typing was both precise and reliable. A total of 7 alleles was found in these populations and no evidence of deviation from Hardy-Weinberg equilibrium was observed. Pairwise comparisons between populations showed that there were significant differences in the distributions of the allele frequencies among the three main ethnic groups. No mutation events were observed from the confirmed father/mother/child triplets. With a maximum likelihood method, the mutation rate was indirectly estimated as 2.5 x 10(-5). These results suggest that D20S161 is a useful marker for forensic casework and paternity analysis.

Asian People↗
PubMed1999

Frequencies of D8S384 alleles and genotypes in European, African-American, Chinese, and Japanese populations.

D8S384 is a tetranucleotide tandem repeat locus. In order to evaluate the forensic validation of D8S384, the genotype distributions and allele frequencies in ten populations from three main ethnic groups were investigated, including Germans, Slovakians, African Americans, Japanese, and Chinese (Jilin, Guangzhou, Nanning, Hailaer, Dali, and Chengdu). A total of 1011 unrelated individuals, 41 pedigrees, 30 disputed paternity trios and three personal identification cases were analyzed for D8S384 by Amp-FLP technique. Many kinds of tissues, body fluids, secreta and stains have been tested. The alleles were determined by comparison with a human allele ladder. The results showed that D8S384 typing was both precise and reliable. There were eight alleles in these populations. The genotype distributions conformed to Hardy-Weinberg equilibrium predictions. No mutation events were observed. With a maximum likelihood method, the mutation rate was indirectly estimated as 2.14 x 10(-5). The heterozygosity was 0.704 +/- 0.014 at D8S384 locus. All these results suggest that D8S384 locus is a useful marker for forensic identification and paternity analysis.

Adult↗
PubMed1999

[Allele and genotype frequency distribution of D19S400 locus in several populations].

Using polymerase chain reaction and PAG electrophoresis, D19S400 Locus was investigated in the populations of Chinese, Germany, Slovakian, and American Black Population. 620 samples collected from the four populations were tested and a total of 11 alleles (*7 to *17) and 47 genotypes were found. The heterozygosity was observed between 0.78 and 0.88, and the discriminating power was between 0.9385 and 0.9664. The distributions of genotypes in the four populations were in accordance with Hardy-Weinberg equilibrium. Significant differences were observed in the distribution of allele frequencies among the three major racial populations (Mongoloid, Caucasian, Negroid). According to the results obtained in this study, D19S400 locus is a robust STR for forensic and genetic purposes.

Alleles↗
PubMed1999

[The manufacture and clinical use of the auto-sialographic instrument by remote controlling]

OBJECTIVE:The purpose of this article is to realize the auto-control of the injection of radiographic drugs in terms of the principle in remote controlling.METHODS:30 cases of sialaden diseases was studied using the auto sialographic instrument by remote controlling,compared to 67 cases studied using sialography by hand-controlling.RESULTS:The auto-sialographic instrument by remote controlling realize the telecontrol of the injection of the sialographic drugs and auto-injection,simplify the working procedure,and prevent medical staffs from X-ray radiation at work.CONCLUSION:The auto sialographic instrument by remote controlling can not only bring much convenience to medical staffs,but also improve the conformation to clinical diagnosis.

Journal Article↗
PubMed1998

Neuronal degeneration and microglial reaction in the fetal and postnatal rat brain after transient maternal hypoxia.

This study examined the neuropathological changes in different areas of the brain of fetal and postnatal rats after transient maternal hypoxia. At different time intervals following hypoxia, reactive microglia as determined immunohistochemically with the antibody OX-42 that recognizes complement type three (CR3) receptors, responded vigorously to the hypoxic stress. Microglial activation was particularly evident in the cingulate cortex and the corpus callosum between 3 h and 14 days after hypoxia. Massive cell degeneration as determined ultrastructurally and significant neuronal loss as evaluated by cell counts were observed in the cingulate cortex at 1 and 3 days after hypoxic insults; thereafter, however, the neuronal density was restored to normal levels. Present results suggest that the cingulate cortex is most vulnerable to the hypoxic injury probably due to a redistribution of cerebral blood flow and/or metabolic changes. Besides being involved in the phagocytosis of cellular debris, it is suggested that the reactive microglial cells may have both neurotoxic and neurotrophic functions.

Animals↗
PubMed1998

Evaluation of in vitro chemosensitivity of antitumor drugs using the MTT assay in fresh human breast cancer.

Practical criteria were developed in this paper for the purpose of evaluating chemosensitivity of fresh human breast cancer by the MTT assay. The survival rates at maximum inhibition (Imax %) and the concentrations of drugs which caused fifty percent reduction in absorbance compared to baseline values (IC50) of 175 samples of 10 anti-tumor drugs were evaluated by logistic analyses of the dose-response curves. Distributions of Imax% appeared as normal curves, while those of the IC50 significantly deviated from normal distribution (p < 0.0001). We assessed the in vitro chemosensitivity by comparing the Imax % of each drug on individual samples with the mean Imax % + SD which was obtained from the Imax% of 175 samples. If the individual Imax % > mean Imax % + SD. we thought the tumor sample was resistant to this drug. If the Imax % < or = mean Imax % + SD, we would compare its IC50 with Q50 which was used as a cutoff point for in vitro chemosensitivity of anti-tumor drugs. The in vitro chemosensitivity could be graded as sensitive (Q1-Q25), intermediate (Q26-Q75), and resistant (Q76-Q100) by means of percentile method. If the individual IC50 > or = Q76, the tumor sample would be defined as resistant. If the individual IC50 < or = Q25, it would be defined as sensitive. In the range of Q26-Q75, we used Q50 as a cutoff point between relative sensitivity and relative resistance. Preliminary results showed that the in vitro chemosensitivity to different anti-tumor drugs determined by these criteria were consistent with the clinical response in 83 advanced breast cancer patients.

Antineoplastic Agents↗