Biomedical subjects

Aimin Zhao

Publications and source records attributed to Aimin Zhao.

4 recordsLinked to original sources

PubMed2005

Refined phylogenetic profiles method for predicting protein-protein interactions.

MOTIVATION: The increasing availability of complete genome sequences provides excellent opportunity for the further development of tools for functional studies in proteomics. Several experimental approaches and in silico algorithms have been developed to cluster proteins into networks of biological significance that may provide new biological insights, especially into understanding the functions of many uncharacterized proteins. Among these methods, the phylogenetic profiles method has been widely used to predict protein-protein interactions. It involves the selection of reference organisms and identification of homologous proteins. Up to now, no published report has systematically studied the effects of the reference genome selection and the identification of homologous proteins upon the accuracy of this method. RESULTS: In this study, we optimized the phylogenetic profiles method by integrating phylogenetic relationships among reference organisms and sequence homology information to improve prediction accuracy. Our results revealed that the selection of the reference organisms set and the criteria for homology identification significantly are two critical factors for the prediction accuracy of this method. Our refined phylogenetic profiles method shows greater performance and potentially provides more reliable functional linkages compared with previous methods.

Algorithms↗

PubMed2005

Association of the A/G polymorphism at position 49 in exon 1 of CTLA-4 with the susceptibility to unexplained recurrent spontaneous abortion in the Chinese population.

PROBLEM: To investigate whether the A/G polymorphism at position 49 in exon 1 of cytotoxic T lymphocyte antigen-4 (CTLA-4) gene, which delivers a negative signal to T-cell activation, confers the susceptibility to unexplained recurrent spontaneous abortion in the Chinese population. METHOD OF STUDY: A total of 168 patients with unexplained recurrent spontaneous abortion (RSA), who were treated in the Renji Hospital affiliated to the Shanghai Second Medical University, were matched against 117 women with normal pregnancy history. Case-control study to compare the frequency of G/A alleles, AA/AG/GG genotypes and A + (AA + AG) /G+ (GG + AG) phenotypes of CTLA-4 between RSA patients and controls were performed. After amplification of CTLA-4 exon-1 region by polymerase chain reaction (PCR), restriction fragment-length polymorphism (RFLP) was used to detect the polymorphism at position 49 in exon-1 of CTLA-4 gene. Statistical significance was tested by SPSS software. RESULTS: There were dissimilar distributions of G/A alleles, AA/AG/GG genotypes and A+/G+ phenotypes of CTLA-4 between RSA patients and controls. The frequencies of G allele (P = 0.032) and GG genotype (P = 0.011) in RSA patients were significantly higher than those in controls, while the frequencies of AG genotype (P = 0.039) and A + (AA + AG) phenotype in RSA patients were decreased significantly (P = 0.011). CONCLUSIONS: Our findings suggest that A/G polymorphism in exon-1 of CTLA-4 is associated with the immunopathogenesis of RSA, and it confers susceptibility to RSA in Chinese population.

Abortion, Habitual↗

PubMed2005

The skewed TCR-BV repertoire displayed at the maternal-fetal interface of women with unexplained pregnancy loss.

PROBLEM: The study was undertaken to investigate T-cell receptor (TCR) variable beta (BV)-chain usage at maternal-fetal interface and explore the relationship between the skewed TCR-BV usage and unexplained pregnancy losses. METHOD OF STUDY: A total of 57 patients with unexplained pregnancy loss including 39 cases with unexplained spontaneous abortion and 18 cases with unexplained recurrent spontaneous abortion (RSA) were chosen in Renji Hospital, Shanghai Second Medical University matched with 41 women with normal pregnancies in first trimester between September 2002 and November 2003. A high-resolution spectratyping analysis of complementarity-determining region 3 (CDR3) was used to detect and compare the degree and pattern of TCR-BV repertoire usage at the maternal-fetal interface between patients with pregnancy loss and normal controls. RESULTS: There were two comparisons of TCR usage performed between patients and controls, which included the degree (mean value of every TCR-BVn expression) and the pattern (skewed TCR-BVn frequency). The skewed TCR-BVn is defined as an absolute BVn usage of > 5% calculated from the formula or a double increased BVn usage compared with the mean value of normal BVn. According to the degree of TCR-BV usage, BV2 (P = 0.046), BV10 (P = 0.016), and BV11 (P = 0.030) in spontaneous abortion group and BV19 (P = 0.038) in RSA group showed higher usage, while BV5.2 (P = 0.006 and P = 0.046) in both abortion groups showed significantly lower usage when compared with normal controls. About the pattern of skewed TCR-BV distribution, we found that TCR-BV2, -3, -6, and -7 were the four most common BV families in deciduas of patients with both types of abortion and normal controls. Women with spontaneous abortion demonstrated higher frequency of BV10 (P = 0.035) and lower frequencies of BV4 (P = 0.002) and BV5.2 (P = 0.003) in comparison with controls. In RSA, higher frequencies of BV15 (P = 0.018), BV19 (P = 0.049), and BV20 (P = 0.018), in the mean time, lower frequencies of BV4 (P = 0.026) and BV7 (P = 0.018) distributions were verified. CONCLUSIONS: Our results suggested that a significant skewed TCR-BV repertoire occurred at the maternal-fetal interface with patients undergoing abortion. The specific skewed usages of TCR-BV might be associated with the susceptibility to unexplained pregnancy loss.

Abortion, Habitual↗

PubMed2002

[Study on the effect of mouse pregnancy immunological tolerance induced by oral antigen administration].

OBJECTIVE: To observe the effect of mouse pregnancy immunological tolerance induced by oral administration of antigens and investigate oral tolerance (OT) therapy of unexplained recurrent spontaneous abortion. METHODS: The mouse models of spontaneous abortion CBA/J x DBA/2 were established, then we administrated the models by oral proper dosage antigens ovum albumin (OVA), trophoblast menbrane antigens trophoblast membrane antigen (TMA)1, TMA2 and observed the changes of embryo loss rate (ELR) as compared with the control groups: group without immunization, group of active immunization by injecting intraperitoneally spleenocytes and blank control by feeding normal saline (NS). RESULTS: (1) The results showed that the ELR of group without immunization, group of active immunization and control blank were 29%, 8% and 28%, respectively. (2) Expect the groups of low dosage single-fed, the ELR can be decreased significantly by oral administration of suitable dosage of antigen OVA and TMA2 as compared with group without immunization and blank control (P < 0.05) and no changes was found as compared with group of active immunization (P > 0.05), the ELR of group OVA 2 mg x 5-fed (4%) and TMA2 2 mg x 5-fed (3%) was the lowest of all. (3) The ELR had not been decreased after administration of TMA1 groups as compared with group without immunization and group blank (P > 0.05). CONCLUSION: The results suggested that pregnancy immunological tolerance can be induced efficiently and the ELR can be decreased significantly by oral administration of proper dosage antigens of OVA and TMA2.

Abortion, Habitual↗