Biomedical subjects

Jun Yin

Publications and source records attributed to Jun Yin.

64 records · Page 4Linked to original sources

PubMed2002

The chemistry of the antibody molecule.

Immunochemistry has traditionally focused on understanding the molecular basis of antibody binding affinity and specificity. In the last 20 years a major shift has occurred in the field. We are now asking how we can exploit the remarkable properties of the antibody molecule and the immune response in chemistry-from testing basic theories of enzymatic catalysis to the synthesis of new catalysts. Moreover, the concept of molecular diversity, which underlies these experiments, is now being applied to a large number of other problems-from libraries of biopolymers to libraries of solid-state materials. Importantly, theses studies are providing fundamental molecular insights into many biological, chemical, and physical phenomena, as well as changing the way we approach the synthesis of new molecular function.

Antibodies↗

PubMed2002

Effects of berberine on glucose metabolism in vitro.

The action of berberine was compared with metformin and troglitazone (TZD) with regard to the glucose-lowering action in vitro. HepG2 cell line, phenotypically similar to human hepatocytes, was used for glucose consumption (GC) studies. Cell proliferation was measured by methylthiotetrazole (MTT) assay. In moderate high glucose concentration (11.1 mmol/L), GC of HepG2 cells was increased by 32% to 60% (P <.001 to P <.0001) with 5 x 10(-6) mol/L to 1 x 10(-4) mol/L berberine, which was comparable to that with 1 x 10(-3) mol/L metformin. The glucose-lowering effect of berberine decreased as the glucose concentration increased. The maximal potency was reached in the presence of 5.5 mmol/L glucose, and it was abolished when the glucose concentration increased to 22.2 mmol/L. The effect was not dependent on insulin concentration, which was similar to that of metformin and was different from that of TZD, whose glucose-lowering effect is insulin dependent. TZD had a better antihyperglycemic potency than metformin when insulin was added (P <.001). In the meantime, a significant toxicity of the drug to HepG2 cells was also observed. The betaTC3 cell line was used for insulin release testing, and no secretogogue effect of berberine was observed. These observations suggest that berberine is able to exert a glucose-lowering effect in hepatocytes, which is insulin independent and similar to that of metformin, but has no effect on insulin secretion.

Berberine↗

PubMed2002

[Identification of two novel mutation in two Chinese hereditary coagulation factor XIII deficiency families].

OBJECTIVE: To explore gene defect of hereditary coagulation factor XIII deficiency. METHODS: PCR and gene sequencing or ARMS-PCR were used to detect the FXIIIA gene of peripheral white blood cell (PBC) from two Chinese hereditary coagulation factor XIII deficiency family members and 60 normal subjects respectively. The level of FXIIIA gene mRNA was tested by RT-PCR. RESULTS: (1) Nucleotide sequence analysis of the two probands' and their family members' DNA revealed that all of the three patients had homozygous missense mutation in FXIII A subunit gene. Proband 1 had a C to G transition at nucleotide (nt) 1 241 in exon 10 and proband 2 and his sister a C to T transition at nt 232 in exon 3 of FXIII A gene, which resulted in the substitution of Ser413 with Trp and Arg 77 with Cys, respectively. Family study showed that the two mutations were inherited from the parents who were correspondingly heterozygotes at nt 1 241 or nt 232. (2) The two mutations were not found in the normal subjects. (3) The FXIIIA gene mRNA level in the two probands was a little decreasing. CONCLUSION: It is the two novel mutations that results in FXIIIA deficiency. The two mutations of FXIIIA gene may affect its function or alter protein folding. The defective FXIII which is unstable and degraded rapidly in cytoplasm may be the main cause of FXIII deficiency.

Blood Coagulation Disorders, Inherited↗

PubMed2002

[Molecular analysis of two pedigrees with hereditary F VII deficiency].

OBJECTIVE: To identify the mutation of coagulation factor VII (F VII) gene in two pedigrees with hereditary F VII deficiency. METHODS: F VII gene mutations were analysed in two propositi and their family members by direct DNA sequencing. Allele specific PCR and PCR combined with restricted enzyme digestion were used to confirm the detected mutations. RESULTS: Two gene mutations were detected in the propositus of pedigree A: G to C transition at position 6390 resulting in Trp40Cys and G to A at 11496 resulting in Arg353Gln, both are heterozygotes. The heterozygosity for polymorphism Arg353Gln was confirmed with the restriction enzyme Msp I digestion in his mother. In the propositus of pedigree B, there was a T to G transition at position 11482 resulting in His348Gln, heterozygosity of which was confirmed with Nsp I digestion in the propositus and his daughter. G to T transition at position 11514 resulting in Thr359Met was also found in the propositus of pedigree B, and the heterozygosity for Thr359Met was confirmed with allele specific PCR in the propositus and his son. CONCLUSION: Three missense mutations were found in two pedigrees with hereditary F VII deficiency. A novel Trp40Cys mutation was reported for the first time.

Factor VII↗

PubMed2002

[Preliminary experimental research on gene therapy for hemophilia A].

OBJECTIVE: To accomplish a kind of therapeutic gene for hemophilia A, and observe the expression of human factor VIII (hF VIII) in vivo. METHODS: Human clotting factor VIII cDNA with B-domain deleted (Delta760aa approximately 1639aa) was inserted into vector pRC/RSV to form pRC/RSV-hF VIII BD, which conjugated with in vivo liposome transfection reagent (DOTAP-Cholesterol) to accomplish a kind of therapeutic gene, pRC/RSV-hF VIII BD-DOTAP-Cholesterol. Mice were injected with pRC/RSV-hF VIII BD-DOTAP-Cholesterol i.m. and sacrificed 48 hours, 10 days, 20 days, 30 days, 40 days and 50 days later, respectively. Tissues such as heart, liver, spleen, lung, kidney and muscle were harvested, the distribution and transcription as well as expression of hF VIII BD cDNA were detected by means of PCR, RT-PCR and immunohistochemistry techniques. In addition, the antigen and antibody of hF VIII in plasma were measured. RESULTS: There was high expression of hF VIII in plasma and tissues at the 48(th) hour after injection. On day 10, antigen level of hF VIII in plasma reached its peak, 17.55 ng/ml, and gradually reduced later. The antibody of hF VIII in plasma emerged on day 10 after injection, and increased and gradually reached 37.06 U/ml on day 50 after injection. PCR, RT-PCR and immunohistochemistry showed that hF VIII BD cDNA and its transcription as well as expression existed in all kinds of tissues, and lasted longer in spleen, lungs and kidneys than in heart, liver and muscle. CONCLUSION: Therapeutic gene, pRC/RSV-hF VIII BD-DOTAP-Cholesterol, produced by combination of pRC/RSV-hF VIII BD and DOTAP-Cholesterol liposome can express human F VIII successfully in vivo, which lays an experimental foundation for curing hemophilia A by gene-drug in clinic.

Animals↗

PubMed2002

Gene cloning of human soluble CD14 and its expression in eucaryotic cells.

OBJECTIVE: To express human soluble CD14 (sCD14) in eukaryotic cells. METHODS: Human sCD14 cDNA was amplified from U937 cells with RT-PCR method. The recombinant expression plasmid pEF1/HisC/sCD14(348aa) was constructed and the expression in COS-7 cells was carried out using liposome transfection method. The yield was examined with scanning map identification. The expressed product was purified by immuno-affinity chromatography. RESULTS: Sequence analysis demonstrated that the amplified gene sequence and those reported by documents were completely identical. sCD14 was expressed with high-yield. The expressed product was purified to above 90%. Recombinant sCD14, specifically combinable with endotoxins, had a natural biological activity. CONCLUSIONS: Human sCD14 was expressed in COS-7 cells, which laid a foundation for further study.

Animals↗

PubMed2002

[Study on plasma coagulation factor VII (FVII) levels and polymorphisms of FVII gene in patients with coronary heart disease].

OBJECTIVE: To investigate the plasma levels of coagulation factor VII (FVII) and polymorphisms of FVII gene in patients with coronary heart disease (CHD), and evaluate the effect of plasma FVII levels and FVII gene polymorphisms on CHD. METHODS: Plasma FVIIa, FVII: Ag and FVIIc were measured and polymorphisms of FVII gene were analyzed in 149 control cases and 60 CHD cases, including 33 acute myocardial infarction (AMI) cases by a combination of polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and agarose gel electrophoresis. RESULTS: FVIIa, FVIIc in AMI group were significantly higher than that in control group, but FVII: Ag wasn't. There were no significant difference in plasma FVIIa, FVII: Ag and FVIIc between CHD and control group. The IVS7 genotypic frequency in AMI group was significantly different from that in control group. There was no significant difference in genotypic frequencies and allelic frequencies in other polymphism sites. FVII: Ag was significantly higher in -402A homozygote than that in -402G homozygote. CONCLUSIONS: Increased FVII levels, especially FVIIa and FVIIc in plasma, may contribute to coronary artery thrombosis. There was significant difference in IVS7 genotype frequency between control and AMI groups, but the rest weren't significantly different. FVII: Ag was significantly higher in -402A homozygote than that in -402G homozygote. Polymorphism of -402 G/A may play an indirect role in AMI by regulating plasma FVII levels.

Coronary Disease↗

PubMed2002

[In vitro expression of human factor VIII gene induced by sodium butyrate].

OBJECTIVE: To explore the effect and mechanism of sodium butyrate on expression of human clotting factor VIII in vitro. METHODS: Mouse NIH/3T3 cell line was transfected with recombinant plasmid vector pRC/RSV-BDD-hFVIII, which enclosed B-domain deleted (760aa approximately 1 639aa) human factor VIII cDNA (BDD-hFVIII cDNA). Then cells were incubated in Dulbecco's modification of Eagle's medium (DMEM) containing sodium butyrate for 24 hours, hFVIII: C and hFVIII: Ag in the cell culture medium were measured by ELISA assay and one-stage method, respectively. In addition, the effect of sodium butyrate on transcription of cDNA encoding the whole hFVIII, heavy and light chain of hFVIII was also investigated by means of run-on assay. RESULTS: After stimulation of sodium butyrate, the levels of hFVIII: C and hFVIII: Ag increased 70% than those of control. Run-on assay showed that sodium butyrate enhanced the transcription of cDNA which encoded heavy chain of hFVIII. CONCLUSION: Sodium butyrate can improve the expression of hFVIII through enhancing the transcription of hFVIII heavy chain encoding cDNA. It demonstrated that sodium butyrate had potential utility in inducing the expression of hFVIII in vitro.

3T3 Cells↗

PubMed2002

[Sperm-mediated expression of human clotting factor VIII gene in transgenic offspring of mice].

The expression of human clotting factor VIII gene was observed in transgenic off spring of mice through artificial insemination with sperm as carriers. Female mice were impregnated through artificial insemination by introducing sperm carrying pRC/RSV-hF VIII BD, which contained human F VIII BD (B-domain deleted) cDNA (hF VIII BD c DNA), into the uteri. During the fourth week after the birth of new-born mice, PCR was used to screen hF VIII BD cDNA positive transgenic mice, then blood of which was collected for detecting the antigen and Anti-hF VIII inhibitors, simultaneously, the transcription and expression of hF VIII BD cDNA were investigated by Northern blot and Western blot. The results showed that 7 became pregnant of 20 inseminated mice, and 11 new-born mice came into the world, out of which 9 survived at last. Three hF VIII BD cDNA-positive-transgenic mice had been screened out by PC R, in which the antigen of human F VIII in plasma was 8.65 ng/ml, 7.84 ng/ml and 8.44 ng/ml, respectively, the Anti-hF VIII inhibitors were all negative. Northern blot and Western blot showed that the transcription and expression of hF VIII BD cDNA existed in tissues such as spleen, liver, lung and kidney of 3 transgenic mice. It was concluded that transgenic mice carrying human F VIII gene can be generated by sperm-carrier techniques and express human F VIII protein. This experiment provides important data for manufacturing transgenic animal carrying human F VIII gene, which can work as a biological reactor to produce human F VIII protein, through sperm-carrier techniques.

Animals↗

PubMed2002

[The principle of extracorporeal shock wave lithotriptor and its locating system].

This article describes in detail the classification of extracorporeal shock wave lithotriptors, charging and discharging circuit of shock wave, wave source and the locating system of the lithotriptor, makes a comparison between three kinds of conventional shock wave sources, and analyzes the advantages and shortcomings of the different locating systems.

Equipment Design↗