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Biomedical subjects

Q Zhang

Publications and source records attributed to Q Zhang.

At least 865 records · Page 48Linked to original sources
PubMed1993

CD38- and Leu6-positive cells in dermal lesions of mycosis fungoides.

The phenotypes of mononuclear cells in 16 patients with mycosis fungoides (MF) (8 were in tumor stage and 8 in pretumor stage) were tested by ABC immunochemical technique. The results showed that the percentage of CD38 and Leu6(+) cells in tumor stage was higher than that in pretumor stage. CD38 was identified to be a marker of the immature lymphocytes. The change of CD38 might be helpful in staging MF and predicting the prognosis of the disease. In addition, Leu6(+) cells, oval or round in shape and without dendritic processes were found in tumor stage, suggesting that they might be immature lymphoid cells. This feature needs further investigation.

ADP-ribosyl Cyclase↗
PubMed1993

[Investigation on insomnia and use of hypnotics among an adult population].

An epidemiological enquiry about the sleep status and use of hypnotics in 1289 adults (742 men and 547 women), including 266 workers, 195 peasants, 275 intellectuals and 553 college students, was done in 1989. A questionnaire including 15 questions on sleep habits, sleep disorders and consumption of hypnotics was used. The response percentages were compared with chi-square test between different sexes, age groups, professions and places of residence. 52.9% and 5.4% of the sample complained of transient and persistent insomnia, respectively. Our data did not reveal sex difference as insomnia is concerned. The response percentages for transient insomnia did not correlate with age, while persistent insomnia definitely increased from middle age. Both transient and persistent insomnia were present much less in rural residents than in towns folks. No significant difference in the incidence of insomnia was found between intellectuals and workers. Only 1.1% of the sample used hypnotics regularly and 10.9% had ever taken sleeping pills.

Adult↗
PubMed1992

Characterization of the promoter region of the porcine opn (osteopontin, secreted phosphoprotein 1) gene. Identification of positive and negative regulatory elements and a 'silent' second promoter.

Osteopontin (secreted phosphoprotein-1, Opn) is a phosphorylated glycoprotein expressed by transformed cells, macrophages, activated T-lymphocytes, specialized epithelial cells and bone cells that is characteristically enriched in milk and in the mineralized matrix of bone. The synthesis of Opn by bone cells is regulated by glucocorticoids and growth factors, which promote bone formation, and by the osteotropic hormone calcitriol (1,25-dihydroxycholecalciferol) and retinoic acid, which mediate bone resorption, indicating a bifunctional role for this protein in bone remodelling. To study the transcriptional regulation of the opn gene, two genomic clones (10 and 15 kb) encoding the opn gene were isolated from a porcine liver genomic library cloned into lambda phage. From the 15-kb clone a 4-kb EcoRI fragment containing the first two exons and 2.6 kb of the 5' flanking region of the opn gene was sequenced, and the transcriptional start site determined by primer extension analysis and S1 nuclease mapping. To identify the opn promoter, chimeric chloramphenicol acetyltransferase constructs were prepared using fragments from the first intron and the 5' flanking region of the opn gene. Transient transfection of porcine bone cells with these constructs showed strong promoter activity located within 74 bp upstream from the transcription initiation site. Within this region a TATA sequence, TTTAAA, was identified at positions -26 to -31. However, the highest transcription rate was observed in a construct extending 180 bp upstream that included a CCGCCC Sp1 binding sequence (-63 to -68), and an AP1 site (-74 to -80). Further upstream in the 5' flanking region and within the first intron of the opn, a number of consensus sequences could be identified. Chimeric constructs containing a GGGTCAtatGGTTCA direct repeat consensus sequence for a vitamin D3 response element located at nucleotides -2245 to -2259 responded to the addition of 0.1 microM calcitriol by a 2.5-fold stimulation of transcription, although a greater than 2-fold increase was also observed in shorter constructs -180 to -905 lacking such a consensus sequence. Promoter activity was also exhibited by a region containing a TTTAAA sequence in the first intron that corresponded to the putative promoter site reported for mouse opn in macrophages (Miyazaki, Y., Setoguchi, M., Yoshida, S., Higuchi, Y., Akizuki, S. & Yamamoto, S. (1990) J. Biol. Chem. 265, 14432-14438).(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acid Sequence↗
PubMed1992

Elevated expression of ICAM1 (CD54) and minimal expression of LFA3 (CD58) in Epstein-Barr-virus-positive nasopharyngeal carcinoma cells.

Undifferentiated nasopharyngeal carcinoma (NPC) is a remarkable entity among human tumors because of its constant association with the Epstein-Barr virus (EBV). Malignant epithelial cells harbor the EBV genome and often express at least 2 species of latent EBV protein (EBNA1 and LMP1). Despite the massive presence of tumor-infiltrating lymphocytes, NPC cells obviously escape immune surveillance directed to EBV antigens. Previous investigations carried out on EBV-positive Burkitt lymphoma (BL) cells have shown that this fact may be partially accounted for by a lack of expression of ICAM1 (CD54) and LFA3 (CD58). ICAM1 and LFA3 have therefore been investigated in fresh NPC biopsies and transplanted NPCs. With only 1 exception out of 9 cases, NPC cells appear to express high levels of ICAM1 and low levels of LFA3. This is a complete inversion of the pattern observed in normal epithelial cells in vivo. Additional investigations will be required to determine to what extent these characteristics affect T-cell interactions with NPC cells, specially in the process of EBV-antigen recognition.

Animals↗
PubMed1992

Temperature-modulated aflatoxin B1 hepatic disposition and formation and persistence of DNA adducts in rainbow trout.

Previous work showed that the incidence of chemically induced tumors in fish increased with environmental temperature. The present study assessed genotoxicity as a mechanism to explain such results. Rainbow trout (2 g) were acclimated to 10 or 18 degrees C for 1 month and then immersed in 0.1 ppm [3H]aflatoxin B1 (AFB1) solutions for 30 min at their respective acclimation temperatures, or at 14 degrees C. The total radioactivity in liver immediately after immersions was 50% higher for 18- than 10 degrees C-acclimated and exposed fish. Conversely, adduction of [3H]AFB1 to hepatic DNA of 10 degrees C-acclimated fish was higher than that of 18 degrees C-acclimated fish after exposure. A similar DNA adduction result was observed after [3H]AFB1 immersion concentrations were varied to achieve similar hepatic [3H]AFB1 equivalents. After acute shifts in temperature (10 to 14 degrees C or 18 to 14 degrees C), no differences were found in hepatic [3H]AFB1 equivalents. However, adduction of [3H]AFB1 to hepatic DNA was higher for 10- than for 18 degrees C-acclimated fish 1 day after exposures at 14 degrees C. This was probably explained by effects of temperature acclimation on the status of the membrane-bound cytochrome P-450 system, affecting its competition with a detoxifying cytosolic enzyme. After [3H]AFB1 immersions at respective acclimation temperatures, or acute temperature shifts to 14 degrees C, DNA adducts were less persistent in fish maintained for 21 days at 18 degrees C than at 10 degrees C. Our data demonstrated that temperature-modulated AFB1 genotoxicity occurred via three mechanisms: hepatic disposition and formation and persistence of DNA adducts.

Aflatoxin B1↗
PubMed1992

Associations between nuclear loci and chloroplast DNA genotypes in wild barley.

Associations among alleles at nine nuclear loci and three chloroplast DNA (cpDNA) genotypes were assessed in a sample of 247 accessions of the wild barley, Hordeum vulgare ssp. spontaneum. Alleles at two of the nine nuclear loci are marked by length variations in the intergenic spacer region of ribosomal DNA (rDNA), and those of the other seven loci are well characterized allozymes. The three chloroplast DNA (cpDNA) genotypes are marked by restriction fragment length polymorphisms resulting from three polymorphic restriction sites detected by Southern blot hybridization. The analyses were performed by dividing the nine nuclear loci into a series of two-locus subsets and constructing log-linear models to characterize associations between the subsets of two nuclear loci and the cpDNA genotypes. Statistically significant associations were detected between six of the nine nuclear loci and the cpDNA genotypes, either individually as pairwise correlations, or through interaction with another nuclear locus to form three-variate complexes. Although the sample size of the present study was inadequate for statistical evaluation of higher order interactions, the results suggest the existence of interactions in which more than two nuclear loci are involved in associations with cpDNA genotypes. The observed cytonuclear associations appear to result from interplay among a number of evolutionary forces including a mating system of predominant selfing, differentiation among gene pools of local populations, and adaptation of barley genotypes to specific environmental conditions.

Blotting, Southern↗
PubMed1992

Evolution of multilocus genetic structure in an experimental barley population.

Data from 311 selfed families isolated from four generations (F8, F13, F23, F45) of an experimental barley population were analyzed to determine patterns of change in character expression for seven quantitative traits, and in single-locus allelic frequencies, and multilocus genetic structure, for 16 Mendelian loci that code for discretely recognizable variants. The analyses showed that large changes in single-locus allelic frequencies and major reorganizations in multilocus genetic structure occurred in each of the generation-to-generation transitions examined. Although associations among a few traits persisted over generations, dynamic dissociations and reassociations occurred among several traits in each generation-transition period. Overall, the restructuring that occurred was characterized by gradual decreases in the number of clusters of associated traits and increases in the number of traits within each cluster. The observed changes in single-locus frequencies and in multilocus genetic structure were attributed to interplay among various evolutionary factors among which natural selection acting in a temporally heterogeneous environment was the guiding force.

Alleles↗
PubMed1992

The proto-oncogene bcl-3 encodes an I kappa B protein.

The bcl-3 gene product, overexpressed in chronic lymphocytic leukemia (CLL) patients with the translocation t(14;19), is a member of the I kappa B family. The bcl-3 protein is able to inhibit the DNA binding and trans-activation of authentic NF-kappa B heterodimers p50-p65 and p49-p65, as well as p50 and p49 homodimers. The bcl-3 protein does not inhibit either the DNA-binding activity of the Rel protein or its ability to trans-activate genes linked to the kappa B site. A human 37-kD protein (I kappa B alpha), identified previously as a member of the I kappa B family, is also unable to inhibit DNA-binding activity of the Rel protein. However, unlike bcl-3, the 37-kD (I kappa B alpha) protein has no effect on the DNA-binding activity of p50 or p49 homodimers. Two dimensional phosphotryptic peptide maps of the human bcl-3 and the human 37-kD (I kappa B alpha) proteins reveal that the phosphopeptides from the 37-kD (I kappa B alpha) protein are nested within the bcl-3 protein. Furthermore, bcl-3 antisera immunoprecipitates an in vitro-radiolabeled 37-kD (I kappa B alpha) protein. Proteins of 56 and 38 kD can be identified in HeLa cells stimulated with PMA and immunoprecipitated with bcl-3 antisera. Comparison of tryptic peptide maps of the bcl-3 protein synthesized in vitro, and p56 and p38 from HeLa cells, shows that they are all structurally related. Removal of the amino-terminal sequences of the bcl-3 protein generates a protein that inhibits the DNA binding of the p50-p65 heterodimer but, like the 37-kD (I kappa B alpha) protein, is no longer able to inhibit the binding of the p50 and p49 homodimers with kappa B DNA. We propose that the bcl-3 and 37-kD (I kappa B alpha) proteins are related and are members of the I kappa B family.

3T3 Cells↗
PubMed1992

Alterations of the p53 gene in nasopharyngeal carcinoma.

Nasopharyngeal carcinoma (NPC) is a malignancy which is consistently associated with the Epstein-Barr virus (EBV). The structure of the EBV genome in NPC suggests that NPC is a clonal proliferation of epithelial cells which emerges after EBV infection. The disease develops with high incidence in specific populations in discrete geographic locations, implicating possible genetic or environmental cofactors. Mutations of the p53 gene are among the most frequent genetic changes found in a large variety of human tumors. Mutations in p53 have been shown to abrogate the suppressor function of wild-type p53 and thus contribute to the transformed phenotype. To determine if mutation in p53 participates in the development of the malignant clone in NPC, the structure and sequence of p53 in 42 primary, metastatic, and nude mouse-passaged NPC specimens was analyzed. A high frequency (6 of 9) of mutations was detected in the nude mouse-passaged tumors, while only 2 of 15 metastatic and 0 of the 18 primary tumors harbored mutant p53. The p53 mutations included single-point mutations and more extensive changes such as frame shifts, deletion, duplication, or complete loss of coding sequences. These data indicate that alterations of the p53 gene are unlikely to be involved in the initial genetic events leading to the clonal outgrowth in NPC. However, although it is a rare NPC which can be established in nude mice, this growth advantage appears to be conferred on tumors bearing a mutant p53.

Animals↗
PubMed1992

The cellular oncogene c-myb can interact synergistically with the Epstein-Barr virus BZLF1 transactivator in lymphoid cells.

Regulation of replicative functions in the Epstein-Barr virus (EBV) genome is mediated through activation of a virally encoded transcription factor, Z (BZLF1). We have shown that the Z gene product, which binds to AP-1 sites as a homodimer and has sequence similarity to c-Fos, can efficiently activate the EBV early promoter, BMRF1, in certain cell types (i.e., HeLa cells) but not others (i.e., Jurkat cells). Here we demonstrate that the c-myb proto-oncogene product, which is itself a DNA-binding protein and transcriptional transactivator, can interact synergistically with Z in activating the BMRF1 promoter in Jurkat cells (a T-cell line) or Raji cells (an EBV-positive B-cell), whereas the c-myb gene product by itself has little effect. The simian virus 40 early promoter is also synergistically activated by the Z/c-myb combination. Synergistic transactivation of the BMRF1 promoter by the Z/c-myb combination appears to involve direct binding by the Z protein but not the c-myb protein. A 30-bp sequence in the BMRF1 promoter which contains a Z binding site (a consensus AP-1 site) is sufficient to transfer high-level lymphoid-specific responsiveness to the Z/c-myb combination to a heterologous promoter. That the c-myb oncogene product can interact synergistically with an EBV-encoded member of the leucine zipper protein family suggests c-myb is likely to engage in similar interactions with cellularly encoded transcription factors.

Amino Acid Sequence↗
PubMed1992

Detection of gene alteration for color vision defects by polymerase chain reaction.

According to the fact that the abnormalities of visual pigment genes were always involved in the changing of the exon 5, two oligonucleotide primers were designed to amplify the exon 5 of red pigment gene and green pigment gene. After electrophoresis of the PCR products digested with Rsal or Sau3A, the DNA fragments from the exon 5 of red pigment gene (RPG) and green pigment gene (GPG) were separated since there are different restriction endonuclease sites. On the other hand, we analyzed the exon 5 related fragment by Southern blot hybridization with probe out of the 3' end of the fourth intron of green pigment gene. The results of PCR are consistent with nucleic acid hybridization. PCR technique will be of value in prenatal evaluation and genetic counselling.

Base Sequence↗
PubMed1992

[The effect of acupuncture on high oxygen pressure-induced convulsion and its relationship to the brain GABA concentration in mice].

This paper reports the effect of acupuncturing "Renzhong" (GV26) and "Chengjiang" (GV24) points on OHP*-induced convulsion in mice. The results are as follows: 1. Convulsion induced by 6 ATA OHP were accompanied with a decrease in the brain GABA concentration. 2. When electro-acupuncture was applied for 15 minutes prior to exposure to hyperoxic chamber, the latency of convulsions was lengthened and the symptoms of seizures were alleviated. Besides, the brain GABA concentration was also elevated remarkably. 3. Administration of vitamin B6 enhanced the effect of acupuncture on convulsions and increased brain GABA concentration. 4. The latency of convulsions was well correlated with the GABA concentration of the brain (r = 0.9867). The above results indicate that acupuncture may elevate endogenous GABA levels in the brain and prevent the hyperbaric-oxygen-induced the decrease in the brain GABA content. Therefore. It is of protective effect against oxygen convulsions. Vitamin B6 may facilitate the effect of acupuncture by improving the GABA metabolism in the brain. In short, the effect of acupuncture against oxygen convulsions may be closely related to the increase in the brain GABA levels.

Acupuncture Therapy↗
PubMed1992

Molecular basis of congenital color vision defects in Chinese patients.

Applying Southern blot hybridization, the structures of the red pigment gene (RPG) and the green pigment gene (GPG) were analyzed in 43 Chinese patients with red-green color vision defects, including 3 female cases of deuteranopia. The same analysis was carried out in 4 normal relatives and 3 carriers from 3 affected families, as well as in 11 normal controls. Among the 43 patients, abnormalities of the RPG were detected in all 19 protans, and abnormalities of the GPG were found in 14 of the 24 deutans. In about 80% of the protans and deutans, an alteration of exon 5 in RPG or GPG was discovered. All 19 protans had anomalous RPG and in one protan the normal RPG was replaced by a 5' red-3' green hybrid gene. However, no protans showed deletion of the whole RPG. Some deutans had no GPG; some had a 5' green-3' red hybrid gene with or without the GPG. The exon 5 of RPG and GPG was amplified by polymerase chain reaction (PCR) and the amplified fragments were further analyzed by RsaI digestion. The results of PCR were identical to those of nucleic acid hybridization. PCR will be a useful tool in prenatal diagnosis and genetic counseling.

Adolescent↗