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Biomedical subjects

D F Zhang

Publications and source records attributed to D F Zhang.

At least 19 recordsLinked to original sources
PubMed2006

Genetic diversity of Triticum turgidum L. based on microsatellite markers.

Using microsatellite (SSR) markers, the genetic diversity and genetic relationships among 48 Triticum turgidum L. accessions, including 30 Triticum turgidum L. ssp. turgidum, 7 Triticum turgidum L. ssp. durum, 4 Triticum turgidum L. ssp. carthlicum, 3 Triticum turgidum L. ssp. paleocolchicum, 2 Triticum turgidum L. ssp. turanicum and 2 Triticum turgidum L. ssp. polonicum accessions, were investigated. A total of 97 alleles were detected on 16 SSR loci. At each locus, the number of alleles ranged from 2 to 14, with an average of 6.1. The Genetic similarity (GS) value ranged from 0.20 to 0.92, with the mean of 0.59. In cluster analysis, it was found the 48 Triticum turgidum L. accessions could be distinguished easily by SSR markers, whereas the 6 subspecies taxonomic entities of T. turgidum L. could not differentiate with each other, indicating that the morphological differences present among the 6 subspecies could not be reflected by the SSR markers. These results suggested that SSR markers had the superiority in detecting the genetic diversity of T. turgidum L., while it was not good for the studies of the phylogenic relationships among the subspecies of T. turgidum L.

Genetic Variation↗
PubMed2002

Optimum ratio of histidine in the piglet ideal protein model and its effects on body metabolism. I. Basal diet formulation based on digestible amino acids according to the ideal protein model for 10 to 20 kg piglets.

A 4 x 4 Latin square design was used to determine ileal apparent digestibility of amino acids (AAs) in corn, soybean meal, feather meal and dried whey in young pigs. The data were then to be used in formulating a basal diet for studies on AA metabolism in young pigs. Eight castrates T-cannulated at terminal ileum (average initial body weight 12.5 +/- 0.62 kg) were divided into 4 groups on the basis of body weight and transferred to individual metabolism crates. They were then fed four experimental diets containing the four feedstuffs to be tested (corn, soybean meal, feather meal and dried whey). The trial lasted 20 days, which included 4 five-day periods for ileal digesta collection. It was found that the digestibility of the AAs was similar to that reported in literature. Based on the findings a basal diet for this research was formulated according to an ideal protein model for the 10 to 20 kg piglet, on the basis of digestible AAs and containing 14.13 MJ/kg digestible energy, 18.22% crude protein, 1.04% digestible lysine and 0.23% digestible histidine.

Amino Acids↗
PubMed2001

Opposing effects of endothelin-1 on C-type natriuretic peptide actions in rat cardiomyocytes.

C-type natriuretic peptide (CNP) and Endothelin-1 are paracrine peptides with opposing vascular and mitogenic actions. In cardiac myocytes, CNP reduced contractility and induced accumulation of cyclic guanosine monophosphate (cGMP). Endothelin-1 caused an increase in contractile amplitude, abolished the negative inotropic effect of CNP, reduced the negative inotropic effect of a membrane permeable cGMP, and inhibited cGMP accumulation induced by CNP. We conclude that endothelin-1 abolishes the negative inotropic effect of CNP. This effect may be mediated by inhibition of the negative inotropic actions of cGMP as well as by reduction of cGMP levels.

Animals↗
PubMed2001

C-type natriuretic peptide has a negative inotropic effect on cardiac myocytes.

C-type natriuretic peptide (CNP) has vasodilatory and antimitogenic actions, but its role in the control of cardiac function is unclear. We studied the effect of CNP on cultured, beating neonatal rat cardiac myocytes. CNP caused a significant reduction in the amplitude of contraction and a significant accumulation of intracellular cyclic GMP. The effect of a membrane permeable cyclic GMP on cell contraction was similar to that of CNP. CNP caused no change in Ca2+ transients. Blockade of natriuretic peptide receptors abolished the effects of CNP on contraction and accumulation of intracellular cyclic GMP. Blockade of cyclic GMP-dependent protein kinase abolished the effect of CNP on myocyte contraction. We conclude that CNP has a negative inotropic effect on neonatal rat cardiac myocytes. The effect of CNP is mediated via natriuretic peptide receptor(s) causing elevation of intracellular cyclic GMP which possibly activates protein kinase and causes attenuation of myofilament sensitivity to Ca2+.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed2001

[Isolation, purification and renaturation of recombinant-DNA-derived porcine somatotropin].

Large scale abstraction and isolation of bacterially synthesized, recombinant-DNA-derived, porcine growth hormone (r-pST) is described. The r-pGH is found in genetic engineering E. coli as the form of inclusion bodies. Pellet fraction which were mainly inclusion bodies, after cell breakage and centrifugation, were collected. Cell envelope components, such as protein, lipid, endotoxin and nucleic acids are selectively removed from the pellet fraction by an EDTA/lysozyme/deoxycholate extraction. Inclusion bodies were dissolved using 6 mol/L guanidine/HCl and air oxidation is then carried out in the presence of the guanidine/HCl. The Guanidine/HCl protein mixture were diluted by renaturation solution. Guanidine/HCl were removed by dialysis and then correctly refolded, oxidized r-pGH were obtained. Injection experiment of hypophysectomized rats proved r-pST with high native bioactivity was obtained.

Animals↗
PubMed1995

[Experimental study on anti-duck hepatitis B viral effect of Phyllanthus urinaria of different areas and combined therapy with other drugs].

The duck hepatitis B virus model was treated with phyllanthus urinaria of different area and combined with Sophora flavesceus as well as ciprofloxacin once a day for one month, the results indicated: Guangxi and Yunnan Phyllanthus could lower the serum DHBV DNA significantly (P < 0.05), but Chongqing Phyllanthus couldn't. And the amount of serum DHBV DNA rose a week after stopping of Yunnan Phyllanthus. The antiviral effect of Guangxi Phyllanthus combined with ciprofloxacin seems to be strengthened (P < 0.05).

Animals↗
PubMed1994

[Isolation purification and identification of a new hepatocyte stimulator peptide].

We have partially purified hepatocyte stimulator peptide (HSP) from liver of human fetus. Immunizing BALB/C mice with crude HSP, we obtained finally 2 antibody-producing colonies, which produced IgG3 and IgG1 revealing clearly the dose dependent inhibitive activity for HSP. Determining the serum HSP and TNF in patients with fulminant hepatic failure, we found that patients with higher HSP/TNF ratio had better prognosis than those with lower ratios. By linking anti-HSP with activated agarose gel, an anti-HSP-sepharose 4B affinity chromatographic column was developed for the isolation of HSP from crude HSP. The result from SDS-PAGE of isolated HSP shows that its molecular weight is about 17.5 KD. Furthermore, HSP has strong growth stimulatory activity for hepatocyte and initiates the DNA synthesis of hepatocyte in vitro. It is not a heparin-binding growth factor and its biological activity is not potentiated by heparin. It is stable at 95 degrees C or pH 2-12 and resistant to 0.25% trypsin digestion for 60 min. These characteristics indicated that HSP might be a novel hepatocyte growth factor and be used in clinical therapy for fulminant hepatic failure and infectious shock. Further study is needed in this respect.

Animals↗
PubMed1993

Serum tumor necrosis factor (TNF) in the pathogenesis of clinical hepatic failure of HCV and/or HBV infection.

Serum TNF and IL-6 levels were measured in 48 patients with liver disease positive for anti-HCV only or concurrent HBV infection. High serum TNF levels were observed in patients with liver disease positive for anti-HCV and/or HBV infection (P < 0.001). Serum TNF levels varied with the severity of liver disease. Serum TNF levels of anti-HCV positive patients with hepatic failure were higher than those with CAH (P < 0.01). Serum TNF levels of patients infected with HCV or concurrent HBV were also significantly higher than those with HBV infection alone (P < 0.001). However, no difference in serum IL-6 levels was observed in either group of patients. Serum TNF in the deceased patients with hepatic failure induced by HBV and HCV infection was higher than in those who survived (P < 0.05), and it also seemed significantly different in patients with and without multiple organ failure (P < 0.05). In vitro, HSS showed marked inhibitory activity on TNF production from PBM induced by endotoxin, but had no significant effect on the TNF cytotoxicity of L929 cells. It seems that high serum TNF level is an important mediator in the pathogenesis of liver necrosis and failure of microcirculation in HCV and/or HBV infection. These observations favor the attempt to treat hepatic failure with HSS or anti-TNF. Encouraging results were achieved using HSS in the treatment of subacute liver necrosis in our institute.(ABSTRACT TRUNCATED AT 250 WORDS)

Enzyme-Linked Immunosorbent Assay↗
PubMed1992

[An etiological study on fulminant viral hepatitis].

Viral markers were studied in 79 cases of viral hepatitis with hepatic failure. The results were shown as follows: 8 cases were positive for anti-HAV IgM (10.12%); 76 cases positive for HBsAg or anti-HBc IgM (96.20%) and 41 cases positive for anti-HCV antibodies (51.89%). Among those with anti-HCV positive, 35 cases were co-infected with HBV, 5 cases with HAV and/or HCV, only one was infected with HCV alone 2 cases were HD-Ag positive (2.52%) and one not identified (1.27%). With the reference of clinical findings, patients co-infected with HBV/HCV or anti-HBc IgM positive were more critical and usually entail higher mortality. In cases with HCV co-infections, the positive HBV replication markers seems to be reduced. Hepatic failure without HBV replicative markers had a high rate of hepatic coma as well as poor outcome.

Adult↗
PubMed1992

[Hepatocyte stimulatory peptide and its clinical significance in viral hepatitis].

Hepatocyte stimulator peptide (HSP) is a new hepatic stimulator substance. Its monoclonal antibodies have been obtained in our laboratory. In this study, HSP was determined in the sera of 315 subjects including patients with various forms of hepatitis and healthy persons with enzyme-linked immunosorbent assay (sandwich method). It is shown that HSP level in the sera of patients with fulminant hepatitis was high and correlated with the level of tumour necrosis factor (TNF), serum bilirubin (SB) or prothrombin time (PT). It is suggested that level of HSP in the sera of the patients reflected the degree of hepatocyte injury. A formula was recommended to predict the outcome of the patients with fulminant hepatitis.

Enzyme-Linked Immunosorbent Assay↗
PubMed1992

Prevalence of antibodies to hepatitis C virus in Chinese patients with viral hepatitis and hepatic failure.

Anti-HCV assay with ORTHO kits was done in 100 blood donors and recipients and 374 cases of viral hepatitis, including 65 cases of fulminant, subacute and chronic hepatic failure. None of the 100 blood donors and recipients showed positive anti-HCV response. Anti-HCV was positive in 7.6% of the patients with chronic persistent hepatitis, 9.7% of the patients with chronic active hepatitis and 23.1% of the patients with liver cirrhosis. High prevalence of anti-HCV was observed in subacute hepatic failure (60.8%) and chronic hepatic failure (53.9%). Fifty-two (83.9%) of 62 anti-HCV positive cases were infected concurrently with HBV. The incidence of HBV replicating marker in patients with HCV or co-infected with HBV was lower than that of those with HBV alone. It is suggested that HCV might inhibit the replication of hepatitis B virus. The mortality rate of patients with anti-HCV positive hepatic failure was higher than that of those with HBV infection. Therefore, anti-viral therapy for anti-HCV positive hepatic failure should be considered.

Adolescent↗
PubMed1991

Immunophenotyping of 515 cases of acute lymphoblastic leukemia in China.

Using cell surface markers and a panel of monoclonal antibodies, 515 cases of acute lymphoblastic leukemia (ALL) were immunophenotyped. T cell type ALL (T-ALL), non-T cell type ALL (Non-T-ALL) including common ALL (C-ALL), Null-ALL and B cell type ALL (B-ALL) were found. These major subtypes of ALL were further divided according to their phenotypes in detail. It was noticed that the phenotypes of these subtypes of ALL reflected basically the phenotypes of normal T or B cells at various differentiation stages or certain population of lymphocytes. The diagnosis of cell lineage was more precise when based on immunophenotyping than morphological description. The combination of morphological and immunological classification can improve the diagnosis of acute leukemias. In addition, it was observed that the immunophenotyping was relevant to clinicopathologic features, responses to therapy and prognosis of ALL patients. The incidences of major subtypes of ALL, the age distribution of ALL subsets and male sex bias with T-ALL in Chinese are discussed.

Adolescent↗
PubMed1990

Hepatitis B surface antigen-specific CD8-positive T cell clones. Antigen specificity and interleukin-2 production.

Clones of hepatitis B surface antigen-reactive CD8+ and CD4+ T cells were obtained from peripheral blood mononuclear cells (PBM) of a hepatitis B immunized individual whose PBM proliferated when cultured with hepatitis B surface antigen (HBsAg). Lymphocytes were activated by culturing for 2 weeks with HBsAg and high concentrations of interleukin-2 (IL-2), then cloned in the presence of irradiated HBsAg-activated PBM and autologous Epstein-Barr virus (EBV)-transformed B cells, together with antigen and IL-2. All clones examined proliferated in an antigen-specific manner. Of 7 clones examined by flow cytometry, 4 were CD4+, CD8-; and 3 were CD4-, CD8+. Several clones produced IL-2 activity after stimulation with hepatitis B surface antigen. Since development of CD8+ T-cell clones specific for soluble antigens is difficult, the high frequency with which CD8+ cells were cloned in these experiments suggests that the cloning strategy employed might have general use for development of CD8+ clones. Availability of hepatitis B virus specific T cell clones of different phenotypes may help elucidate mechanisms of immunotolerance in hepatitis B infection.

CD4-Positive T-Lymphocytes↗
PubMed1989

[Preliminary study on HBsAg-specific T cell clones].

Clones of HBsAg-reactive CD8+ and CD4+ T cells were obtained from PBM of a hepatitis B immunized individual whose PBM proliferated when cultured with HBsAg. Lymphocytes were activated by culturing for 2 weeks with HBsAg and high concentrations of IL-2, then cloned in the presence of irradiated HBsAg-activated PBM and autologous EBV-transformed B cells, together with antigen and IL-2. All clones examined exhibited proliferation in an antigen-specific manner. Of 7 clones examined by flow cytometry, 4 were CD4+, CD8-; and 3 were CD4-, CD8+. Several clones produced IL-2 activity after stimulation with HBsAg. Since development of CD8+ T-cell clones specific for soluble antigens has been difficult, the high frequency with which CD8+ cells were cloned in these experiments suggests that the cloning strategy employed may have general use for development of CD8+ clones, Availability of HBV-specific T cell clones of different phenotype may help elucidate the mechanisms of immunotolerance in HB infection.

Clone Cells↗
PubMed1989

[B-cell differential factor (IL-6) in peripheral mononuclear cells in viral hepatitis B infections].

B-cell differential factor (BCDF) activities were determined in 58 patients with various types of hepatitis B. In comparison with normal subjects, BCDF activities were significantly increased in patients with FH and CAH (P less than 0.01), markedly decreased in HBsAg carriers (P less than 0.01) and presented no change in patients with CPH and AH. It is interesting that there was a significant positive correlation between BCDF activity and serum titer of anti-HBC or serum globulin levels. No correlation was observed between BCDF activity and serum anti-HBs levels. It is suggested that abnormal BCDF activity might attribute to aberration of immunoregulation of HBV infections.

Adult↗