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Xu Ma

Publications and source records attributed to Xu Ma.

13 recordsLinked to original sources
PubMed2025

Genome-wide DNA methylation and transcriptome sequencing analyses of lens tissue in an age-related mouse cataract model.

DNA methylation is known to be associated with cataracts. In this study, we used a mouse model and performed DNA methylation and transcriptome sequencing analyses to find epigenetic indicators for age-related cataracts (ARC). Anterior lens capsule membrane tissues from young and aged mice were analyzed by MethylRAD-seq to detect the genome-wide methylation of extracted DNA. The young and aged mice had 76,524 and 15,608 differentially methylated CCGG and CCWGG sites, respectively. The Pearson correlation analysis detected 109 and 33 differentially expressed genes (DEGs) with negative methylation at CCGG and CCWGG sites, respectively, in their promoter regions. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) functional enrichment analyses showed that DEGs with abnormal methylation at CCGG sites were primarily associated with protein kinase C signaling (Akap12, Capzb), protein threonine kinase activity (Dmpk, Mapkapk3), and calcium signaling pathway (Slc25a4, Cacna1f), whereas DEGs with abnormal methylation at CCWGG sites were associated with ribosomal protein S6 kinase activity (Rps6ka3). These genes were validated by pyrosequencing methylation analysis. The results showed that the ARC group (aged mice) had lower Dmpk and Slc25a4 methylation levels and a higher Rps6ka3 methylation than the control group (young mice), which is consistent with the results of the joint analysis of differentially methylated and differentially expressed genes. In conclusion, we confirmed the genome-wide DNA methylation pattern and gene expression profile of ARC based on the mouse cataract model with aged mice. The identified methylation molecular markers have great potential for application in the future diagnosis and treatment of ARC.

Animals↗
PubMed2006

Deficit of mitochondria-derived ATP during oxidative stress impairs mouse MII oocyte spindles.

Although the role of oxidative stress in maternal aging and infertility has been suggested, the underlying mechanisms are not fully understood. The present study is designed to determine the relationship between mitochondrial function and spindle stability in metaphase II (MII) oocytes under oxidative stress. MII mouse oocytes were treated with H2O2 in the presence or absence of permeability transition pores (PTPs) blockers cyclosporin A (CsA). In addition, antioxidant N-acetylcysteine (NAC), F0/F1 synthase inhibitor oligomycin A, the mitochondria uncoupler carbonyl cyanide 4-trifluoro-methoxyphenylhydrazone (FCCP) or thapsigargin plus 2.5 mM Ca2+ (Th+2.5 mM Ca2+) were used in mechanistic studies. Morphologic analyses of oocyte spindles and chromosomes were performed and mitochondrial membrane potential (DeltaPsim), cytoplasmic free calcium concentration ([Ca2+]c) and cytoplasmic ATP content within oocytes were also assayed. In a time- and H2O2 dose-dependent manner, disruption of meiotic spindles was found after oocytes were treated with H2O2, which was prevented by pre-treatment with NAC. Administration of H2O2 led to a dissipation of DeltaPsim, an increase in [Ca2+]c and a decrease in cytoplasmic ATP levels. These detrimental responses of oocytes to H2O2 treatment could be blocked by pre-incubation with CsA. Similar to H2O2, both oligomycin A and FCCP dissipated DeltaPsim, decreased cytoplasmic ATP contents and disassembled MII oocyte spindles, while high [Ca2+]c alone had no effects on spindle morphology. In conclusion, the decrease in mitochondria-derived ATP during oxidative stress may cause a disassembly of mouse MII oocyte spindles, presumably due to the opening of the mitochondrial PTPs.

Acetylcysteine↗
PubMed2006

Genome-wide microRNA profiling in human fetal nervous tissues by oligonucleotide microarray.

OBJECTS: Our objective was to develop an oligonucleotide DNA microarray (OMA) for genome-wide microRNA profiling and use this method to find miRNAs, which control organic development especially for nervous system. MATERIALS AND METHODS: Eighteen organic samples included cerebrum and spinal cord samples from two aborted human fetuses. One was 12 gestational weeks old (G12w) and the other was 24 gestational weeks old (G24w). Global miRNA expression patterns of different organs were investigated using OMA and Northern blot. CONCLUSION: The OMA revealed that 72-83% of miRNAs were expressed in human fetal organs. A series of microRNAs were found specifically and higher-expressed in the human fetal nervous system and confirmed consistently by Northern blot, which may play a critical role in nervous system development.

Age Factors↗
PubMed2006

Redox-induced apoptosis of human oocytes in resting follicles in vitro.

BACKGROUND: The age-related depletion of the resting follicle (RF) stock occurs as a result of two processes: atresia and entry in growth phase. Due to difficulties in obtaining sufficient numbers of RFs for study, little is known about the apoptotic mechanisms for RF atresia. The present study was designed to investigate the effects of oxidative stress on the apoptosis of RF oocytes. METHODS: RFs isolated from human adult ovaries were cultured in vitro, treated with H2O2 at various concentrations (50 microM, 100 microM, 1.0 mM) for 1 hour, and observed for up to 48 hours. The oxidant-induced apoptosis of oocytes were observed by detection of DNA fragments, mitochondria membrane potential (MMP), and cytochrome c release. RESULTS: Based on nuclear morphology and TUNEL (terminal deoxynucleotidyl transferase-mediated dDTP nick end-labeling), oocyte apoptosis was observed in the RFs treated with 50 microM H2O2 with rates of 35% and 43% at 24 and 48 h after treatment, respectively. But intensive oxidative stress (1 mM H2O2) caused mainly necrosis as measured by quantifying propidium iodide (PI)-positive oocytes (44% within 12 hours), with lower level of apoptosis (17%) being observed at 24 hours after treatment. RFs treated with 100 microM H2O2 showed both apoptosis with the similar rate observed at 50microM and necrosis (13% PI-positive oocytes). Although pre-incubation with cyclosporine A (CsA) could effectively prevent oxidant-induced MMP collapse, but failed to suppress apoptosis of oocytes in RFs. CONCLUSIONS: Oocytes of RFs in adult ovaries retain their ability to undergo apoptosis under oxidative stress, which is both dose- and time-dependent.

Adult↗
PubMed2006

Second-trimester double or triple screening for Down syndrome: a comparison of Chinese and Caucasian populations.

OBJECTIVES: To compare the performance of double screening (measuring maternal serum levels of alpha-fetoprotein [AFP] and total beta-human chorionic gonadotrophin [hCG] as markers for Down syndrome) with that of triple screening (also measuring levels of unconjugated estriol [uE3]) in the second trimester of pregnancy, and to compare ethnic variance between Chinese and Caucasian populations. METHODS: The study investigated 15096 normal singleton pregnancies and 24 pregnancies affected with Down syndrome. Frequency distributions of AFP, hCG, and uE3 levels were analyzed. Likelihood ratios (LRs) were calculated using the multiple of median value (MoM) of AFP, hCG, and uE3 as variables. After multiplying maternal age risk by the LR values for the markers used in double and triple screening, the specific risks obtained with double and triple screening were estimated. The detection rate (DR) and false-positive rate (FPR) were calculated at different cut-off points. The serum markers' levels were also compared with those of Caucasian women. RESULTS: The median MoM value of hCG was higher in women with affected pregnancies (1.40) than those with unaffected pregnancies (1.00). However, the median MoMs of AFP and uE3 (0.79 and 0.68) were lower in affected than in unaffected pregnancies. At a FPR of 5%, the detection rates reached with double and triple screening were 50% and 66.7%, respectively. Ratios of the 3 serum markers' medians to those in a study with Caucasian women were 1.06 (range=1.04-1.09) for AFP, 1.14 (range=1.10-1.17) for hCG, and 1.28 (range=1.23-1.41) for uE3 for the relevant gestational weeks. CONCLUSION: Triple screening performed better than double screening in the second trimester. Ethnic variance should be taken into account in Down syndrome screening.

Adult↗
PubMed2006

A missense mutation in the gammaD-crystallin gene CRYGD associated with autosomal dominant congenital cataract in a Chinese family.

PURPOSE: To identify the genetic defect in autosomal dominant congenital cataracts in a six generation Chinese family. METHODS: Clinical and ophthalmological examinations were performed on the affected and unaffected family members. All the members were genotyped with microsatellite markers at loci which were considered to be associated with cataracts. A two-point LOD score was calculated using the Linkage package after genotyping. A mutation was detected by direct sequencing using gene specific primers. RESULTS: Clinical heterogeneity was observed within this family, three affected individuals showed nuclear cataract and others had coralliform cataracts. Significant evidence of linkage was obtained at markers D2S325 (LOD score [Z]=3.10, recombination fraction [theta]=0.0) and D2S1782 (Z=5.97, theta=0.0), respectively. Haplotype analysis indicated that the cataract gene was close to those two markers. Sequencing of the gammaD-crystallin gene (CRYGD) revealed a C>T transition in exon 2, that causes a conservative substitution of Arg to Cys at codon 14 (R14C). This mutation co-segregated with all affected individuals and was not observed in unaffected or 100 normal unrelated individuals. Bioinformatic analyses also showed that a highly conserved region was located at Arg14. CONCLUSIONS: This study is the first reported case with phenotype of coralliform/nuclear cataract that associated with the mutation of Arg14Cys (R14C) CRYGD.

Adolescent↗
PubMed2006

A differentially methylated region of the DAZ1 gene in spermatic and somatic cells.

AIM: To investigate the methylation status of the deleted in azoospermia 1 (DAZ1) gene promoter region in different cell types. METHODS: Using CpG island Searcher software, a CpG island was found in the promoter region of the DAZ1 gene. The methylation status of this region was analyzed in sperm and leukocytes by bisulfited sequencing. RESULTS: The methylation status of the CpG island in the DAZ1 gene promoter region differed in leukocytes and sperm: it was methylated in leukocytes, but unmethylated in sperm. CONCLUSION: A differentially methylated region of the DAZ1 gene exists in spermatic and somatic cells, suggesting that methylation of this region may regulate DAZ1 gene expression in different tissues.

Base Sequence↗
PubMed2006

Erectile dysfunction in Fragile X patients.

AIM: To report the clinical experience during collecting sperm samples in the Fragile X syndrome (FXS) male patients. METHODS: Two different polymerase chain reaction (PCR) based methods were used for the molecular diagnosis of FXS. Sperm collection was done mostly according to the laboratory manual of the World Health Organization. RESULTS: We failed to collect sperm samples from five Fragile X subjects aged 18-60 years as a result of an unexpected erectile dysfunction (ED). Multiple examinations of the same subject at different times, and of different subjects from different provinces examined by different physicians, showed the same result consistently in all the five subjects. CONCLUSION: Erectile reflex is an instinctive response in all healthy males. The absence of erection can be caused by hormonal, physical or neuronal malfunction. As hormonal profiles were reported to be generally normal in Fragile X men, we propose that an unknown physical factor or the neuronal circuit, or both, underlying the erection is compromised. The finding of this symptom in Fragile X patients may help better understand the clinical spectrum and pathogeneses of the disease.

Adolescent↗
PubMed2006

[CAG repeats of DNA polymerase gamma in Chinese males and relationship of idiopathic male infertility to CAG repeats].

OBJECTIVE: To analyze the polymerase gamma(Polg) gene polymorphisms in Chinese idiopathic infertile males and evaluate the correlation of the polymorphisms with male infertility. METHODS: We conducted a study of Polg CAG repeats in the sperm or blood DNA of 55 asthenospermia patients, 57 oligospermia patients, 34 azoospermia patients, and 104 controls with PCR and GeneScan. Phenotypic data were available in all the subjects, including semen parameters, and clinical profiles. RESULTS: The frequency of 10/not 10 CAG genotype in asthenospermia patients was higher than in the other groups, but with no significance. CONCLUSION: Our findings have shown for the first time that there exits an ethnic difference between Chinese and European males in the number of CAG repeats of Polg gene, and that 10/not 10 CAG genotype may affect sperm motility.

Adult↗
PubMed2005

[(CAG) n polymorphism of androgen receptor gene in idiopathic azoospermic and oligospermic Chinese men].

OBJECTIVE: To research (CAG)n polymorphism of androgen receptor gene in idiopathic azoospermic and oligospermic Chinese men, and to explore its correlation with the development of dyszoospermia. METHODS: Fifty-two men with oligospermia and 31 with azoospermia were enrolled, the number of CAG sequence repeats determined by PCR and denaturing polyacrylamide gel electrophoresis (PAGE), and (CAG)n polymorphism analyzed. RESULTS: The CAG repeats in the men with oligospermia and those with azoospermia were 22.19 and 22.13 respectively. CONCLUSION: The polymorphism of the repeat length of the (CAG) n satellite in androgen receptor gene may affect spermatogenesis and have a less important role in male infertility.

Adult↗
PubMed2005

[Evaluation of correlation between gelatin crosslinking indicators and influence factors].

AIM: To evaluate the correlation between the swelling equilibrium quantity (Seq), dissolution rate and amino group content which were used to estimate the degree of gelatin crosslinking, and the factors which influence the crosslinking, and to investigate the crosslinking mechanism of delayed dissolution of soft capsules. METHODS: The swelling equilibrium quantity, dissolution rate and amino group content of formaldehyde-crosslinked capsule shells were determined. Gelatin structure was analyzed by means of DSC. RESULTS: A good lineal relativity was found between the swelling equilibrium quantity, dissolution rate and amino group content (r = 0.9953-0.9985). The Seq of capsule shells was influenced by high temperature, lighting and some additives. Glycine and sodium pyrosulfite might retard the decrease of Seq of capsule shells. CONCLUSION: The swelling equilibrium quantity, dissolution rate and amino group content exhibited the same rule in gelatin crosslinking extent. High temperature, lighting and some additives might induce gelatin crosslinking. Antioxidant such as glycine and sodium pyrosulfite might retard the crosslinking.

Amino Acids↗
PubMed2004

[Cytochrome P450 2C19 gene polymorphism in 104 Chinese Zang volunteers].

Cytochrome P 450 2C19 (CYP2C19) is involved in the metabolism of a number of clinically used drugs. Individuals can be characterized as extensive metabolizers (EMs) or poor metabolizers (PMs) , according to the drugs-metabolized ability of CYP2C19 in population studies. The incidence of poor metabolizer phenotype shows marked interracial differences. In this article we report the gene polymorphism of CYP2C19 in Zang population. There were 49 wild-type homozygotes (wt/wt) , 46 were heterozygotes (wt/m1) and 9 were homozygotes (m1/m1) among 104 unrelated Zang subjects. The frequency of CYP2C19(m1) allele was 0.308, which was in agreement with that in other published data.

Adolescent↗