Biomedical subjects

Xin-Yao Wu

Publications and source records attributed to Xin-Yao Wu.

14 recordsLinked to original sources

PubMed2006

[How to draw a conclusion in motherless parentage testing using short tandem repeats as genetic makers].

OBJECTIVE: To calculate the exclusion power of STR loci in motherless parentage testing and to discuss how to draw a conclusion if there are inconsistent loci. METHODS: Based on the law of inheritance and allele frequency, the powers of exclusion of STR loci in motherless parentage testing (PE(M)) were calculated. Based on the mean PE(M) and mutation rate of 13 CODIS loci. The probabilities of inconsistence under paternity and non-paternity were calculated respectively according to binomial theorem. RESULTS: The PE(M) of locus having co-dominate alleles could be calculated as: PE(M) = (i = 1)sigma (n) p i 2(1-p (i))2+ (i < j)sigma (n) 2p (i)p (j)(1-p (i)-p (j))2. According to the formula, the average PE(M) of 13 CODIS was 0.411. Based on the mean PE(M) and mutation rate, the likelihood ratio of true father to random man (paternity index) was got using binomial theorem. CONCLUSION: The conclusion in motherless parentage testing could be drawn based on the likelihood ratio (paternity index) derived from mean PE(M) and mutation ratio.

Algorithms↗

PubMed2006

[Sequence analysis of DYS522 and DYS527 loci and their genetic polymorphism among Guangdong Han population].

Analyzed the sequence characteristics and the genetic polymorphism of two new Y-STR loci: DYS522 and DYS527, in 151 unrelated Han males in the Guangdong Province. The results show that the DYS522 locus consists of repeats of a core sequence (GATA), with the number of repeats ranging between 9 and 13. The DYS527 locus contains two copies of a sequence motif. This motif has the following modular structure: (GGAA)3...(GGAA)2...(GGAA)2...(GGAA)3...(GGAA)4...(GGAA)3...(GAAA)m(GGAA)n, where the value of (m + n) ranges between 18 and 26 among different individuals. A rare copy with 15.3 (m+n) repeats was found. Altogether, 63 different haplotypes of these two loci were identified. Of these, 29 occurred only once, with a frequency of 0.0066, and the most common haplotype occurred at a frequency of 0.0728. This system has a haplotype diversity (HD) of 0.9780, and a discriminating power (DP) of 0.9715. The analysis of 38 father/son pairs has detected no mutation event at the DYS522 and DYS527 loci within any pair. It is found that these two loci are specific to the human species. These results indicate the DYS522/DYS527 loci to be highly polymorphic and useful genetic markers in forensic science and human evolution studies.

Alleles↗

PubMed2006

[Genetics of heteroplasmy in the mtDNA control region among the Chinese Han population].

OBJECTIVE: To explore the distribution and genetic pattern of heteroplasmy of mtDNA control region among Chinese Han population. METHODS: The human mtDNA control region was amplified into 6 amplicons overlapped partially each other. Then these amplicons were analyzed by DHPLC which we developed to detect low heteroplasmic signals. RESULTS: There were 51 heteroplasmic cases (34%) found from different tissues of 150 unrelated individuals of the Chinese Han population. mtDNA heteroplasmy shows non-uniform distribution in various tissues. The highest occurrence of heteroplasmy was in brain tissues (50/150) and myocardium (48/150), the lowest was in bone tissues (22/150). 36 sites of heteroplasmy were identified in our samples. Three sites of mtDNA heteroplasmy rarely co-existed in one individual. No sex differences were detected in the frequency of mtDNA heteroplasmy. No change in the mtDNA heteroplasmy profile was detected of blood samples from the same individuals within 2 years. Individuals older than 41 years showed a heteroplasmy frequency significantly higher than their younger counterparts. Members from the same maternal pedigree in a family can share the same sites of mtDNA heteroplasmy but may have different heteroplasmy contents at those sites. CONCLUSION: DHPLC is a highly sensitive technique in detecting heteroplasmy. mtDNA heteroplasmy widely exists in the Chinese Han population. The results shown here could potentially have a guidable value in forensic individual identification and parentage testing.

Adolescent↗

PubMed2006

[Radiosensitization of nasopharyngeal carcinoma cell line CNE1 by inhibiting the expression of ATM/PI3K functional region].

BACKGROUND & OBJECTIVE: It is reported that ATM gene is closely correlated to cellular radiosensitivity in several malignant tumors. Suppression of ATM protein expression leads to cellular radiosensitization. This study was to determine whether this effect also exists in nasopharyngeal carcinoma (NPC) cell line CNE1 by inhibiting the expression of ATM protein through antisense RNA of ATM/PI3K region, which is the most important functional fragment of ATM gene. METHODS: The recombinant pDOR-atm expressing antisense RNA of ATM/PI3K segment was constructed with retroviral vector pDOR. CNE1 cells were stably transfected with pDOR-atm by cationic liposome and named CNE1/pDOR-atm. Semi-quantitive RT-PCR was used to detect the level of ATM mRNA. Flow cytometry (FCM) was employed to analyze the percentage of positive cells and mean fluorescence density of protein expressing ATM. Cellular radiosensitivity was evaluated by colony survival assay (CSA) and linear-quadratic model in both CNE1/ pDOR-atm and control cells. RESULTS: The level of ATM mRNA index (RI) was 0.23+/-0.02 in CNE1/pDOR-atm group, and 0.51+/-0.03 in control group (P<0.05). The percentage of positive cells and mean fluorescence density of proteins expressing ATM were 70.8% and 1.81+/-0.12 in CNE1/pDOR-atm group, while 99.3% and 4.51+/-0.18 in control group(P<0.01). The expression of ATM mRNA and protein was inhibited by antisense RNA. The alpha value (one function from linear-quadratic model) of CNE1/pDOR-atm group was 0.40 Gy(-1), while it was 0.36 Gy(-1) in control group. The radiosensitizing ratio of surviving fraction at 2 Gy (SF(2)) was 3.0, indicating that antisense RNA group was more radiosensitive to X-ray than the controls. CONCLUSION: NPC cell line CNE1 could be radiosensitized by the down-regulation of ATM/PI3K expression.

Ataxia Telangiectasia Mutated Proteins↗

PubMed2004

Antiproliferation effects of oridonin on HL-60 cells.

The antiproliferation effects and inhibition of telomerase activity of oridonin on leukemic HL-60 cells were studied. HL-60 cells in culture medium were treated with different concentrations of oridonin. The inhibitory rate of the cells was measured by MTT assay. Cell apoptotic rate was detected by flow cytometry (FCM). Morphology of cell apoptosis was observed by Wright's stain. Reverse transcriptase polymerase chain reaction (RT-PCR) and PCR-enzyme-linked immunosorbent assay (ELISA) were used to detect hTERT mRNA expression and telomerase activity before and after apoptosis. Oridonin (over 8 micromol/l) could inhibit the growth of HL-60 cells and cause apoptosis significantly. The suppression was in both time-dependent and dose-dependent manner. Marked morphological changes of cell apoptosis including condensation of chromatin and nuclear fragmentation were observed clearly by Wright's stain especially after the cells were treated 48-60 h by oridonin. The expression of hTERT mRNA as well as activity of telomerase were decreased concurrently by treatment with oridonin in HL-60 cells. Oridonin can downregulate the hTERT mRNA expression and decrease the telomerase activity of HL-60 cells; it has apparent antiproliferation and apoptosis-inducing effects on HL-60 cells in vitro.

Apoptosis↗

PubMed2004

[Short tandem repeat polymerase chain reaction used in prenatal diagnoses of the zygosity and common chromosomal trisomies in multiple pregnancies].

OBJECTIVE: To evaluate the value of short tandem repeat polymerase chain reaction (STR-PCR) in identification of zygosity in multiple pregnancy and detection of the common chromosomal trisomies. METHODS: Amniotic fluid or fetal blood samples were collected from 38 fetuses in 17 multiple pregnant women who had indications for prenatal diagnosis or planed to be performed feticide. Of the 17 cases there were 13 sets of twins (26 fetuses) and 4 sets of triplets (12 fetuses). Parental blood samples were collected. STR-PCR technique was employed to determine the zygosity and detect trisomy 21, trisomy 18, trisomy 13, and trisomy sex chromosomes. Amniotic fluid or blood samples were collected from 18 singleton pregnant fetuses as controls for detecting chromosomal trisomies. RESULTS: All 7 cases with gestation by assisted reproductive techniques were multizygotic. In 7 cases associated with one fetal malformation, only one set of twin was dizygotic. There were no above mentioned trisomies found in the multiple pregnancies while 2 trisomy 21, one trisomy 18 and 13 respectively were detected in the singleton pregnant group. Feticide was performed on 4 multizygotic cases in which 3 were triplets and 1 was twin associated with an abnormal fetus. Following-up showed that there was no any bad effect after procedure. CONCLUSION: STR-PCR can be used in identifying the zygosity correctly and quickly while being used in detecting chromosomal trisomies. It facilitates monitoring multiple pregnancy as well as selecting appropriate methods of feticide.

Adult↗

PubMed2004

Anti-proliferation effect of oridonin on HL-60 cells and its mechanism.

OBJECTIVE: To investigate the anti-proliferation effect of oridonin on leukemic HL-60 cells and its mechanism. METHODS: HL-60 cells in vitro in culture medium were given different concentrations of oridonin. The inhibitory rate of cells were measured by microculture tetrazolium (MTT) assay, cell apoptotic rate was detected by flow cytometry (FCM), morphology of cell apoptosis was observed by hoechst 33258 fluorescence staining, and the activity of telomerase was detected using telomere repeat amplification protocol (TRAP) PCR-ELISA before and after apoptosis occurred. RESULTS: Oridonin could decrease telomerase activity, inhibit growth of HL-60 cells, and cause apoptosis significantly. The suppression was both in time- and dose-dependent manner. Marked morphological changes of cell apoptosis including condensation of chromatin and nuclear fragmentation were observed clearly by hoechst 33258 fluorescence staining especially after cells were treated 48-60 hours by oridonin. CONCLUSIONS: Oridonin has apparent anti-proliferation and apoptotic effects on HL-60 cells in vitro, decreasing telomerase activity of HL-60 cells may be one of its most important mechanisms. These results will provide strong laboratory evidence of oridonin for clinical treatment of acute leukemia.

Antineoplastic Agents, Phytogenic↗

PubMed2004

[ATM and telomere instability].

Accumulation of DNA damage has been associated with the onset of senescence and the predisposition to cancer. The gene responsible for ataxia telangiectasia (A-T) is ATM (Ataxia-telangiectasia mutant), a master controller of cellular pathways and networks, orchestrating the response to a specific type of DNA damage, i.e., the double strand break. It has now been demonstrated that mutations in ATM lead to defective telomere maintenance in mammalian cells. This review will focus on its roles in telomere metabolism and how ATM and telomeres serve as controllers of cellular responses to DNA damage.

Ataxia Telangiectasia↗

PubMed2004

[The characteristics of polymorphism and gene structure of DYF155S1 locus in Y-specific minisatellite from Chinese Uygur population].

The study is to reveal the diversity and gene structure of 5' and 3' end of DYF155S1 locus in Y-chromosome minisatellite among Chinese Uygur population. Fluorescent MVR-PCR(minisatellite variant repeat by PCR), Amp-FLP(Amplified fragment length polymorphism) and DNA sequencing methods were used respectively to detect 106 unrelated males among Chinese Uygur population. The polymorphisms of DYF155S1 locus could be revealed in three aspects: (1) polymorphic length: the sizes of amplified fragments ranged from 1405 to 2505 bp. There are 37 types found among the 106 unrelated males. (2) polymorphism at 5' end of DYF155S1 locus, 68 types found among the 106 unrelated males. (3) polymorphism at 3' end of DYF155S1 locus, 23 types found among the 106 unrelated males. In combination of these three aspects of polymorphism, none of the 106 unrelated males tested had the same allele, and the gene diversity (h) was over 0.9999. Seven and two types of modular structure were founded in the 5' and 3' end of DYF155S1 locus, respectively, by DNA sequencing. The alleles at DYF155S2 locus showed yes/no dimorphism and the rate of deletion was 4.7%. The polymorphisms of DYF155S1 locus were fully revealed by using combination of MVR-PCR, Amp-FLP and DNA sequencing methods, and we suggested the nomenclature for alleles of MVR loci. These methods are useful tools and provide basic data for the study of human genetics and forensic medicine.

Alleles↗

PubMed2003

[Studying the polymorphism at DYF155S1 locus in Chinese Han population by MVR-PCR marked with fluorescence].

The simple and useful genotyping methods of DYF155S1 locus by silver staining and fluorescence detection have been established. The blood samples from 155 unrelated males in Chinese Han population were typed by these two methods respectively and the same results were obtained. Among the 155 samples 66 alleles were found, out of them 38 were observed once only. The most frequent alleles named 18 or 22, which frequency was 0.065, the size of their first DNA fragments was 180 bp and the number of fragments was 16 or 17. The gene diversity (h) was 0.9789. Out of the 155 samples, 25 samples had one or two bands lost (null repeat) among the successive bands. It was demonstrated by sequencing that the position of the lost bands corresponded to type 3 repeats. Our results indicated that the method, which revealed the 5' end diversity of DYF155S1 locus, was a technique that could obtain the most Y-specific polymorphic information only by one PCR reaction. The allele frequencies of DYF155S1 locus in Chinese Han population provided the basic data for the study of population genetics and forensic practices.

Alleles↗

PubMed2003

[Expression of ATM protein in nasopharyngeal carcinoma cell lines with different radiosensitivity].

BACKGROUND & OBJECTIVE: It has been reported that ataxia- telangiectasia mutant(ATM) protein is closely correlated with cellular radiosensitivity in several malignant tumors. This study was designed to determine the expression of ATM protein in two nasopharyngeal carcinoma (NPC) cell lines with different radiosensitivity. METHODS: Two NPC cell lines, CNE1 and CNE2, with different radiosensitivity were established. The localization and quantity of ATM protein were analyzed by fluorescence immunohistochemical method and laser scanning confocal microscope(LSCM). RESULTS: ATM protein was located in both karyon and cytoplasm, especially strongly expressed in karyon. The intense fluorescence of ATM protein was stronger in karyon of CNE1 than that in CNE2. CONCLUSION: The expression levels of ATM protein differ in CNE1 and CNE2. The variance may be a potential factor, which links with their different radiosensitivity.

Ataxia Telangiectasia Mutated Proteins↗

PubMed2003

[Sequence variation of D12S391 and D11S554 loci in Guangzhou han population].

To study the core sequence of the hypervariable short tandom repeats, we sequenced the alleles of D12S391 and D11S554 loci which show high mutation rate in Guangzhou Han population. The D12S391 locus has the basic sequence structure (AGAT)8-17 (AGAC)6-10 (AGAT)0-1. The smaller alleles (15-18) at D12S391 locus have variation limited to the number of the first repeat (AGAT), whereas the larger alleles (19-27) have more complex variation in the number not only of the first repeat but also of the other two repeats (AGAC) and (AGAT). Four new alleles named 22", 23", 24"' and 27 respectively were found. The D11S554 locus has more complex core sequence classified into five sequence types. Three of them have the same basic sequence structure (AAAGG) (AAAG)4 (AAAGG)2-3 (AAAG)13-19. In the larger alleles (219-249), there are four and five nucleotide repeats. Some of the larger alleles(219-249) have one base variation, bases insert or deletion. The two loci all have sequence heterogeneity. Our results indicated that the two loci D12S391 and D11S554 belong to complex repeats and this adds difficulty to their correctly typing. It is essential to construct allelic ladder in each population.

Alleles↗

PubMed2003

[Study on mutation of ATM/PI3K region in NPC cell lines with different radiosensitivity].

To try to elucidate the relationship between the radiosensitivity of NPC cell lines and ATM gene, this study was designed to investigate the mutation of ATM/PI3K region in NPC cell lines with different radiosensitivity. Two NPC cell lines of CNE1 and CNE2 with different radiosensitivities were established. Reverse transcriptase polymerase chain reaction (RT-PCR) was used to get a 546bp fragment (8578nt-9123nt) of ATM cDNA, containing the PI-3 kinase domain (8753-8815bp). Direct sequencing of RT-PCR product was applied to determine the mutations in the gene. The sequence of the 546bp fragment is identical to the sequence of ATM gene published in GenBank, that is, there are no any mutations on the fragment of ATM/PI3K we examined either in CNE1 or in CNE2. It indicates that there may be no correlations between the mutation of ATM/PI3K and the variation of radiosensitivity in NPC cell lines CNE1, CNE2.

English Abstract↗

PubMedDate not supplied

Rapid detection of six common Chinese G6PD mutations by MALDI-TOF MS.

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a common X-linked hereditary enzymopathy. We describe here the techniques based on matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) and multiprimer extension (multi-PEX) to detect the most common Chinese G6PD mutations, which are the single-point mutations G-->T at nt 1376, G-->A at nt 1388, A-->G at nt 95, G-->T at nt 392, C-->T at nt 1024, and C-->T at nt 1311. Fifteen samples were genotyped using this method coupled with direct sequencing, after identification of G6PD mutations by ARMS. In this study, we identified a mutation G-->T at nt 1376, which had been G-->A at nt 1388 using ARMS, while the result of sequencing corresponds with ours. This indicates the reliability of this method. Furthermore, since it can scan six common Chinese G6PD mutations simultaneously in one mass spectrum, this approach could be used to fast diagnose these G6PD mutations accurately in large-scale analysis.

China↗