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Biomedical subjects

Y Liang

Publications and source records attributed to Y Liang.

At least 307 records · Page 17Linked to original sources
PubMed1995

A gene for congenital, recessive deafness DFNB3 maps to the pericentromeric region of chromosome 17.

Two percent of the residents of Bengkala, Bali, have profound, congenital, neurosensory, nonsyndromal deafness due to an autosomal recessive mutation at the DFNB3 locus. We have employed a direct genome-wide disequilibrium search strategy, allele-frequency-dependent homozygosity mapping (AHM), and an analysis of historical recombinants to map DFNB3 and position the locus relative to flanking markers. DFNB3 maps to chromosome 17, closest to D17S261, pRM7-GT and D17S805. In individuals homozygous for DFNB3, historical recombinant genotypes for the flanking markers, D17S122 and D17S783, place DFNB3 in a 5.3 cM interval of the pericentromeric region of chromosome 17 on a refined linkage map of 17p-17q12. Based on conserved synteny, the murine sh2 gene may be the homologue of DFNB3.

Alleles↗
PubMed1995

Analysis of short tandem repeat (STR) allele frequency distributions in a Balinese population.

Genotypes for 53 short tandem repeat (STR) markers distributed at an average of 39 cM intervals throughout the genome were determined for 46 individuals from the village of Bengkala, Bali. This village of approximately 2200 individuals has an oral and written tradition suggesting genetic bottlenecks. The allele frequency distributions in Bengkala were compared with distributions obtained by typing individuals in the CEPH data base using a Kolmogorov-Smirnov two sample test. Twenty-eight of the 53 markers showed differences (P < 0.05) in distribution between the two populations. Allele frequencies of tetranucleotide STRs were much more similar between the two populations than were those of dinucleotide STRs (P < 0.043). Population heterogeneity in Bengkala was indicated by an excess of observed homozygosity, deviations from Hardy-Weinberg equilibrium at seven loci, and significant allelic associations between physically unlinked loci. In addition to providing information pertinent to the issue of genetic diversity of STRs in the human population, these analyses serve as a resource to map a gene causing non-syndromal autosomal recessive deafness in Bengkala, and to corroborate the anthropological study of the history and social structure of the village.

Alleles↗
PubMed1995

Evidence for inter-generational instability in the CAG repeat in the MJD1 gene and for conserved haplotypes at flanking markers amongst Japanese and Caucasian subjects with Machado-Joseph disease.

The size of the (CAG)n repeat array in the 3' end of the MJD1 gene and the haplotype at a series of microsatellite markers surrounding the MJD1 gene were examined in a large cohort of Japanese and Caucasian subjects affected with Machado-Joseph disease (MJD). Our data provide five novel observations. First, MJD is associated with expansion fo the array from the normal range of 14-37 repeats to 68-84 repeats in most Japanese and Caucasian subjects, but no subjects were observed with expansions intermediate in size between those of the normal and MJD affected groups. Second, the expanded allele associated with MJD displays inter-generational instability, particularly in male meioses, and this instability was associated with the clinical phenomenon of anticipation. Third, the size of the expanded allele is not only inversely correlated with the age-of-onset of MJD (r = -0.738, p < 0.001), but is also correlated with the frequency of other clinical features [e.g. pseudoexophthalmos and pyramidal signs were more frequent in subjects with large repeats (p < 0.001 and p < 0.05 respectively)]. Fourth, the disease phenotype is significantly more severe and had an early age of onset (16 years) in a subject homozygous for the expanded allele, which contrasts with Huntington disease and suggests that the expanded allele in the MJD1 gene could exert its effect either by a dominant negative effect (putatively excluded in HD) or by a gain of function effect as proposed for HD. Finally, Japanese and Caucasian subjects affected with MJD share haplotypes at several markers surrounding the MJD1 gene, which are uncommon in the normal Japanese and Caucasian population, and which suggests the existence either of common founders in these populations or of chromosomes susceptible to pathologic expansion of the CAG repeat in the MJD1 gene.

Age of Onset↗
PubMed1995

Polymorphism at the P450IIE1 locus is not associated with alcoholic liver disease in Caucasian men.

Because alcoholic hepatitis and cirrhosis, well-known complications of alcohol abuse, do not occur in all alcoholics, genetic factors such as differences in alcohol-metabolizing enzymes may play a role in the development of alcoholic liver disease. Cytochrome P450IIE1 catalyzes the oxidation of ethanol, producing acetaldehyde and free radicals capable of reacting with and peroxidizing cell membranes. Polymorphisms have been identified in the 5'-flanking region of the P450IIE1 gene that may alter the transcriptional activity of the gene. In this study, we analyzed the P450IIE1 genotypes at the polymorphic PstI and RsaI restriction enzyme sites in 53 Caucasians with severe alcoholic liver disease to determine if there is an association between these polymorphisms and alcoholic liver disease. Subjects that tested positive for the hepatitis C virus were eliminated from the study. To identify the type A (homozygous for the c1 gene), type B (heterozygous for the c1 and c2 genes), and type C (homozygous for the c2 gene) genotypes at the P450IIE1 locus, DNA encompassing the polymorphisms was amplified by polymerase chain reaction, slot-blotted, and probed with allele-specific oligonucleotides. Allele frequencies for the c1 allele were 0.95 for alcoholics with severe liver disease, 0.95 for alcoholics without liver disease, and 0.98 for the general population. No differences in allele frequencies between alcoholic patients with severe liver disease and alcoholics without liver disease were observed.

Adult↗
PubMed1995

Congenital non-syndromal autosomal recessive deafness in Bengkala, an isolated Balinese village.

Bengkala is an Indonesian village located on the north shore of Bali that has existed for over 700 years. Currently, 2.2% of the 2185 people in this village have profound congenital deafness. In response to the high incidence of deafness, the people of Bengkala have developed a village specific sign language which is used by many of the hearing and deaf people. Deafness in Bengkala is congenital, sensorineural, non-syndromal, and caused by a fully penetrant autosomal recessive mutation at the DFNB3 locus. The frequency of the DFNB3 mutation is estimated to be 9.4% among hearing people who have a 17.2% chance of being heterozygous for DFNB3.

Alleles↗
PubMed1995

[Basaloid squamous carcinoma of the oesophagus: a distinctive clinico-pathological entity].

5 cases of basaloid-squamous carcinoma (BSC) of oesophagus were reported. Their pathological features were: 1. The main component of the tumors were basaloid carcinoma cells. 2. Concomitant squamous cell differentiation. 3. Comedo-like necrosis in the basaloid carcinoma component of the tumor. 4. Hyaline degeneration within the stroma of the basaloid carcinoma nests (PAS+). The immunohistochemistry of keratin 10.11, CEA and EMA in the basaloid carcinoma component of BSC were negative or weak positive, while actin and S-100 were positive in some parts of the tumor sections. This suggested that the carcinoma component was poorly differentiated and somewhat tended to differentiate toward myoepithelia or other directions. We therefore consider that the origin of BSC may be the primitive totipotential cell. BSC occurred more frequently in elderly males. The biological behavior of BSC was highly malignant. Regional lymph nodes or distant organ metastasis were usually found at the first operation. The mean survival period after operation was very short, BSC was therefore considered to be a specific clinicopathological entity.

Actins↗
PubMed1995

[Onco-gene c-fos expression in light-damaged human embryo retinal pigment epithelium and protective effect of taurine and gamma-interferon].

We used well-cultured human embryo retinal pigment epithelial (RPE) cells to establish a light-damaged RPE cell model. There was no onco-gene c-fos expression in RPE cells cultured under normal condition. Immediately after 30 minutes of light exposure, onco-gene c-fos expression occurred in the RPE cells. The expression reached the highest level 1.5 hours after light exposure and disappeared 4 hours later. Taurine and gamma-interferon in different concentrations could restrain onco-gene c-fos expression in light damaged RPE cells. The restraint effects were of concentration dependence.

Cells, Cultured↗
PubMed1995

[Immuno histochemical study of endothelin-1 in breast cancer].

Endothelin-1 (ET-1) content was measured in tissue sections from 42 human breast cancer from grade 1 to grade III and from 8 normal breast tissue by immunohistochemistry and image analysis methods. The ET-1 was stained as brownish grains localized in the cytoplasm of tumor cells and normal breast epithelial cells. However, both the proportion of ET-1 positive cells and ET-1 cellular content were significantly higher in cancer cells than in normal breast epithelium. Moreover, the ET-1 content in the tumor cells was inversely correlated with the degree of tumor cell differentiation. It is suggested that ET-1 is synthesized by human breast cancer and its over expression may induce an abnormal proliferation of breast tissue and result in malignant growth.

Adult↗
PubMed1995

[A preliminary study on the antenatal diagnosis and prevention of the fetus toxoplasmosis infection].

For those pregnant women with an abnormal pregnancy history, the polymerase chain reaction (PCR) technique was adopted to screening the serum toxoplasmosis DNA (TOX-DNA). Then tests were made for further evidence of TOX-DNA in the amnionic fluids TOX-DNA was examined in cases with blood TOX-DNA positive. Gamma glutamyl transpeptidase (GGT) and alpha-fetoprotein (AFP) in the amnionic fluids were measured for reference, a antenatal diagnosis of the fetal congenital toxoplasmosis infection could thus be made. In the present paper, 9 out of 92 blood specimen were TOX-DNA positive, of the 9 cases, 5 had TOX-DNA and 4 had no TOX-DNA in the amnionic fluid tests. The results of follow-up examination in the 9 cases were in conformity with the ante natal diagnosis. This is an important procedure for diagnosis and prevention of maternal-fetal vertical infection of Toxoplasmosis.

Animals↗
PubMed1995

[Detection of HBV DNA and HBsAg in HCC and pericarcinomatous tissues using double labelling technique].

40 cases of hepatocellular carcinoma (HCC) and their surrounding tissues were studied on paraffin-embedded sections by in situ hybridization and immunohistochemical double labelling techniques. The positive rates of HBV DNA and HBsAg were 65% and 82.5% respectively, suggesting that HBV infection is a significant cause of HCC. HBV DNA and HBsAg signals in the pericarcinomatous tissues were stronger than that in cancer cells. Reduced replication caused by integration of HBV DNA in HCC may explain this phenomenon. We found that the small "piece-meal like" inclusions which existed only in HCC may be a special cancer related pattern of HBsAg. There were stronger signals of HBsAg in the small cell LCD than in other pericarcinomatous lesions, supporting the theory that the small cell LCD is more likely to be a precarcinomatous lesion.

Carcinoma, Hepatocellular↗
PubMed1995

[Effects of lead on neurobehavior and neurochemistry in rats].

Effects of exposure to lead on neurobehavioral function, content of monoamine neurotransmitter in hippocampus, and brain level of lipid peroxide were studied in 45 SD rats. Results showed learning and memory abilities of the rats were affected in exposure to lead of 1333.3 mg/kg (with their blood lead level of 6.23 mumol/L), their motor activities changed and emotional status became unsteady with 266.7 mg/kg of lead (with blood lead of 4.20 mumol/L) and 1333.3 mg/kg of lead, respectively, and levels of dopamine neurotransmitter and its metabolites declined and those of lipid peroxide increased with increasing exposure to lead. It is postulated changes in levels of neurotransmitter, such as monoamine and lipid peroxide, could explain the mechanism for damage in neurobehavioral function caused by lead exposure.

Animals↗
PubMed1995

Increased detection of specific tyrosine phosphoproteins correlates with tumor progression of Abelson virus-infected lymphocytes.

Leukemias induced with the v-abl or BCR/ABL oncogene undergo a process of tumor progression which suggests that the ABL oncogene is required but not sufficient for full transformation. In order to identify cellular changes that correlate with progression to full transformation in v-abl transformed lymphoblasts Abelson virus (A-MuLV)-infected murine bone marrow was plated over a pre-established stromal feeder layer. Shortly after A-MuLV infection, transformed lymphoblasts were poorly oncogenic, but over time, progressed in a stepwide manner to a more oncogenic state. The transformants first acquired the ability to grow efficiently in agar, but only over the feeder layer. They next progressed to efficient feeder-independent growth in liquid culture, and then to efficient feeder-independent growth in soft agar. Cell lines that reached the advanced stage of feeder-independent agar growth showed increased detection by antiphosphotyrosine Western blot of the GAP-associated p62 phosphoprotein as well as of a 55 kDa phosphoprotein while detection of the P160 v-abl phosphoprotein remained constant throughout all stages of progression. Although the identity of the p55 phosphoprotein and the mechanism by which detection of p55 and p62 phosphoproteins change on the Western blots during tumor progression are unknown, the data demonstrate that these changes strongly correlate with the stage of progression of v-abl-transformed cells and raise the possibility that these changes may play a role in tumor progression in this model.

3T3 Cells↗
PubMed1995

Increased expression of NADPH-diaphorase in visual centres after unilateral optic nerve transection in the rat.

The present study shows an increase NADPH-d histochemical staining in the optic layers of the superior colliculus, the ventral nucleus of the lateral geniculate body and the primary visual cortex in the rat after transection of the contralateral optic nerve. The alteration was observed 4-60 days after the lesion, with a maximum at 30 days. These results suggest that retinal activity has a transneuronal and time-dependent regulatory effect on nitric oxide synthesis in denervated or visually deprived visual centres, an increase that may play a role in enhancing local blood flow and could be neuroprotective in function.

Animals↗
PubMed1995

[Correlation between p53 nuclear protein accumulation and mutations of the p53 gene in human esophageal cancer from linxian].

Thirty-three esophageal tumors were analyzed by immunohistochemistry for P53 nuclear protein accumulation, and the results were compared to p53 gene mutations by PCR-direct sequence analysis. A highly significant correlation between the presence of p53 mutations and p53 nuclear protein accumulation was found. Of 33 tumors, 23 (69.7%) that demonstrated P53 protein expression 12(36%) had p53 mutations. Of 12 tumors with p53 mutations, 9 tumors showed P53 intensive nuclear reactivity. The results reported here are consistent with the idea that p53 mutations may be an important biological event in esophageal cancer progression and P53 expression was correlated with p53 gene mutation.

Adenocarcinoma↗
PubMed1994

Nonrandom cytogenetic changes accompany malignant progression in clonal lines abelson virus-infected lymphocytes.

Initially, lymphoid cells transformed by v-abl or BCR/ABL oncogenes are poorly oncogenic but progress to full transformation over time. Although expression of the oncogene is necessary to initiate and maintain transformation, other molecular mechanisms are thought to be required for full transformation. To determine whether tumor progression in ABL oncogene-transformed lymphoid cells has a genetic basis, we examined whether progression of the malignant phenotype of transformed clones correlates with particular cytogenetic abnormalities. A modified in vitro bone marrow transformation model was used to obtain clonal Abelson murine leukemia virus-transformed B lymphoid cells that were poorly oncogenic. Multiple subclones were then derived from each clone and maintained over a marrow-derived stromal cell line for several weeks. Over time, clonally related Abelson murine leukemia virus-transformed subclones progressed asynchronously to full transformation. The data show that tumor progression can occur in the absence of detectable cytogenetic changes but, more importantly, that certain cytogenetic abnormalities appear reproducibly in highly malignant subclones. Therefore, three independent subclones showed deletion in a common region of chromosome 13. Other highly malignant cells carried a common breakpoint in the X chromosome, and, finally, two subclones carried an additional chromosome 5. These results are consistent with the hypothesis that ABL oncogenes are sufficient for the initial transformation of cells but that additional genetic events can drive oncogenic progression. These observations further suggest that diverse genetic mechanisms may be able to drive tumor progression in cells transformed with ABL oncogenes.

Abelson murine leukemia virus↗