Shaochun Bai

The Novel Gene Locus for Agenesis of Permanent Teeth (He-Zhao deficiency) Maps to Chromosome 10q11.2

He-Zhao deficiency has been recently characterized with a distinct form of agenesis of permanent teeth that is different from other previously reported disorders of tooth agenesis. This inherited abnormality suggests that some gene(s) associated with the development of permanent teeth may mutate. In this study, we map the gene locus to chromosome 10q11.2. The DNA pooling method combined with two-point and multi-point linkage analysis has been successfully applied. The maximum LOD (Zmax) scores for two-point and multi-point analyses are 13.29 (on marker D10S196) at recombination fraction (θ) = 0 and 18.09 (between markers D10S1772 and D10S1766), respectively. Haplotype analysis confined the locus within an interval of 5.5 cM flanked by markers D10S604 and D10S568. This study has demonstrated a novel gene locus responsible for He-Zhao deficiency and provides a good likelihood for the discovery of one of the genes determining permanent tooth formation and development.

Association of APOE gene with schizophrenia in Chinese: a possible risk factor in times of malnutrition

Five hundred and seventy nine Chinese patients with schizophrenia who met DSMIV criteria for the disorder were genotyped for alleles epsilon 2,3,4 of apolipoprotein E (APOE) gene. All were recruited from inpatients and outpatients attending a large mental health centre in Shanghai. Results were compared to APOE data on 1528 controls drawn from the same area. Major differences in APOE genotype ratios and allele frequencies were observed between the patients and controls. The patients with schizophrenia had highly significantly (p<0.0001) increased epsilon 4/-genotypes and allele frequencies, and decreased epsilon 3/3 genotypes and epsilon 3 allele frequencies compared to controls. The effect was independent of sex and/or age of onset of illness, but strongly influenced by date of birth. Significant differences were restricted to individuals with schizophrenia born either before 1949 or during the period 1958-1967. Both were times of severe food shortages and malnutrition. We suggest that APOE may operate as an additional risk factor for schizophrenia in individuals subjected to fetal and/or early postnatal malnutrition.

Genetic Polymorphism of Cytochrome P450 4F2, Vitamin E Level and Histological Response in Adults and Children with Nonalcoholic Fatty Liver Disease Who Participated in PIVENS and TONIC Clinical Trials

Vitamin E improved liver histology in children and adults with NAFLD who participated in TONIC and PIVENS clinical trials, but with significant inter-individual variability in its efficacy. Cytochrome P450 4F2 (CYP4F2) is the major enzyme metabolizing Vit E, with two common genetic variants (V433M, rs2108622 and W12G, rs3093105) found to alter its activity. We investigated the relationship between CYP4F2 genotypes, α-tocopherol levels and histological improvement in these two trials. V433M and W12G variants were genotyped in TONIC (n = 155) and PIVENS (n = 213) DNA samples. The relationships between CYP4F2 genotypes, plasma α-tocopherol levels at baseline and weeks 48 (w48) and 96 (w96) and histological end points (overall improvement in liver histology and resolution of NASH) were investigated. As a result, the V433M genotype was significantly associated with baseline plasma α-tocopherol in the TONIC trial (p = 0.004), but not in PIVENS. Among those receiving Vit E treatment, CYP4F2 V433M genotype was associated with significantly decreased plasma α-tocopherol levels at w48 (p = 0.003 for PIVENS and p = 0.026 for TONIC) but not at w96. The w96 α-tocopherol level was significantly associated with resolution of NASH (p = 0.006) and overall histology improvement (p = 0.021)in the PIVENS, but not in the TONIC trial. There was no significant association between CYP4F2 genotypes and histological end points in either trial. Our study suggested the a moderate role of CYP4F2 polymorphisms in affecting the pharmacokinetics of Vit E as a therapeutic agent. In addition, there may be age-dependent relationship between CYP4F2 genetic variability and Vit E pharmacokinetics in NAFLD.

A locus for congenital preauricular fistula maps to chromosome 8q11.1–q13.3

AbstractThe incidence of congenital preauricular fistula (CPF) is >1.1% in both Chinese and Caucasians, but it is even higher in Blacks. We mapped the locus for CPF to chromosome 8q11.1–q13.3 by linkage analysis of a family composed of 7 affected and 11 nonaffected members. The two-point LOD score was 2.40, shown by markers D8S285 and D8S1113 at a recombination fraction (θ) of 0.00. Results from three other markers (D8S1110, D8S260, and D8S1136) in the same region further support the linkage. Haplotype analysis for this family confined the locus to within an interval of approximately 26.7cM, flanked by markers D8S532 and D8S279. A LOD score of <3 is likely due to the limitation of family size.

Genome-wide search for loss of heterozygosity in Chinese patients with sporadic colorectal cancer

In an attempt to integrally investigate the loss of tumor suppressor genes and search for putative suppressor loci associated with tumor occurrence and progression, we conducted a genome-wide loss of heterozygosity (LOH) study of 83 tumor samples obtained from Chinese patients with sporadic colorectal cancer. We employed 400 fluorescence-labeled microsatellite marker primers to amplify the corresponding loci of the genomic DNA and then electrophoresed the polymerase chain reaction products and analyzed the fluorescent signals. The LOH frequencies were high (>35%) but were not associated with the tumor stage and progression in 20 loci, including the regions where TP53, E-cadherin, deleted in colorectal carcinoma (DCC), phosphatase and tensin homolog deleted on chromosome 10 (PTEN), mothers against decapentaplegic, Drosophila, homolog of 2 (MADH2) and mothers against decapentaplegic, Drosophila, homolog of 4 (MADH4) reside. Loss of other loci, including two narrow regions on chromosome 2, was found to relate to the tumor stage, suggesting that this genomic instability may contribute to tumor progression.

Application of FLUPD-DD-PCR to the study of mRNA expression of glioma cells cultured under the condition of serum starvation

Fluorescently labeled universal primer directed differential display polymerase chain reaction technique (FLUPD-DD-PCR), an improved DD-PCR, is reported for the study of mRNA expression of glioma cells cultured with the serum starvation. The fluorescently labeled universal primer (FLUP) facilitates analysis of PCR products on an auto-sequencer. Compared with the traditional DD-PCR, FLUPD-DD-PCR has advantages of separation of target bands and measurement of mRNA expression quantitatively by adopting Cy5-labeled universal primer. And then the silver staining method has been used to recover the bands for use as template in re-pcr. In this study, 4 differential ESTs, of which 3 are novel ESTs, have been obtained. This work indicates some special novel genes, which can be induced to express under serum absent condition, are involved in coping with serum starvation stress on glioma cells growth.

Another Mechanism Causing the Bystander Effect Besides the GAP Junction’s Role During the Glioma Gene Therapy With HSV-TK/GCV System

Human gene therapy has progressed from speculation to reality in the last several decades, and it has also been exploited in the field of the glioma treating. Due to the glioma having multiple varied genetic mutations, the antisense or target gene replacement are not so feasible for the treatment of these malignant tumors, that a novel approach named ‘suicide gene strategy’ has been performed. This method involves the transfer of the herpes simplex virus thymidine kinase (HSV-TK), whose production is capable of converting non-toxic prodrug—ganciclovir (GCV) to toxic metabolism, phosphated GCV, so the target tissue would be susceptible to destruction through the activation of the prodrug1–3. During this treatment of the glioma, a phenomenon named ‘bystander effect’ has been paid much attention, this is beacause GCV induced cytotoxicity is not only to the HSV-TK positive tumor cells, but also to the HSV-TK negative cells4,5. Although considerable attention has been directed toward the elucidating the mechanism underlying the bystander effect, little is known about how bystander cells can be rendered susceptible to GCV. In this study, we attempted to determine the possible mechanism of the bystander effect. We employed rat glioma cell line A15A5, which is TK-negative, and TF10.2, which were A15A5 cells transfected with TK gene. Another cell line we used is the C6 cell line, and C6-TF-PEGFP which were C6 transfected with PEGFP(Enhanced Green fluorescence protein).