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Biomedical subjects

G Yang

Publications and source records attributed to G Yang.

At least 109 records · Page 6Linked to original sources
PubMed2001

[Detection of methylation status of p16 tumor suppressor gene in soft tissue leiomyosarcoma].

OBJECTIVE: To observe the methylation status of p16 tumor suppressor gene in human soft tissue leiomyosarcoma (LMS) and its relationship with p16 protein expression. METHODS: Methylation-specific PCR (MSP) assay was used to analyze the methylation status of 5' CpG island promoter/exon I region of p16 tumor suppressor gene in 38 LMS, 10 leiomyomas and 5 normal smooth muscle tissues. p16 expression in these tissues were examined by immunohistochemical assay. RESULTS: Hypermethylation of p16 was observed in 23.7% (9/38) of cases, of which 7 with negative pl6 staining and 2 with faint positive staining. In the cases without protein expression, hypermethylation rate of p16 was 50% (7/14). CONCLUSIONS: Epigenetic change due to 5' CpG methylation is the main cause of inactivation of p16 (INK4) gene which may be involved in tumor pathogenesis.

CpG Islands↗
PubMed2001

[Studies of intercellular communication in human rhabdomyosarcoma cell lines of different metastatic potential].

OBJECTIVE: To investigate the relationship between intercellular communication and three human rhabdomyosarcoma (RMS) cell lines of different metastatic potential. METHODS: Indirect immunofluorescent staining and laser scanning confocal microscope (ISCM) were used to detect connexin 43 (CX43), a molecule related with gap junctional intercellular communication (GJIC). Fluorescence redistribution after photobleaching (FRAP) was used to detect function of GJIC. RESULTS: A high level of CX43 protein expression was revealed in normal human myoblasts. CX43 protein was mainly localized on the surface of cells and sometimes in cytoplasm. CX43 expression was decreased in RMS cells. Both the detection rates and fluorescent intensity of CX43 decreased when the metastatic potential of RMS increased (P < 0.05). In contrast to normal, the fluorescence recovery rates of the RMS cells decreased and there was a negative correlation between the function of GJIC and malignancy of RMS cell lines (P < 0.05). CONCLUSION: Varying degrees of GJIC inhibition may correlate with different metastatic potential of RMS. This may help to determine the malignant behavior of RMS and be used as a prognostic index of RMS.

Animals↗
PubMed2001

[Effects of metal ions on gamma-poly (glutamic acid) synthesis by Bacillus licheniformis].

In the course of gamma-poly (glutamic acid) gamma-PGA fermentation, metal ions K+, Mg2+, Fe3+, Ca2+, Mo6+, Mn2+, Co2+ and Zn2+ in the medium have certain effects on the synthesis of gamma-poly(glutamic acid). Excess or lack of K+, Mg2+ and Fe3+ results in reduced yield of gamma-PGA. It was found that the gamma-PGA synthesis by Bacillus licheniformis was promoted obviously by Ca2+ and Mo6+. Synthesis and stereochemical composition of gamma-PGA was greatly regulated by Mn2+. gamma-PGA was not produced without Mn2+ in medium, and with the increase of Zn2+ concentration the yield of gamma-PGA and the proportion of D-glutamic acid in the peptide increase. Regulative effect of Co2+ and Zn2+ was almost the same as that of Mn2+, thus the combination of Mn2+, Co2+ cannot enhance gamma-PGA synthesis and affect stereochemical composition of gamma-PGA. Based on the experimental date, an appropriate formulation of metal ions in the medium for gamma-PGA production was obtained.

Bacillus↗
PubMed2001

[Prospective study of combination of interferon-alpha with ribavirin for treatment of chronic hepatitis C in children].

OBJECTIVE: To explore more efficacious therapy for chronic hepatitis C in children. METHODS: With combination of recombinant interferon-alpha/ribavirin therapy, we treated 15 children, with viral sera and biopsy-proven chronic hepatitis C, who did not respond to the treatment of interferon-alpha alone and had frequently relapse, with the disease courses of 5-9 years (mean 4.5 years). Mean age of the children (12 males and 3 females) was 6.8 years (6 months-10 years). 14 patients had blood transfusion history. RESULTS: HCV RNA in 12 patients was negative after combined treatment of 3 months (1.5-5 months). None of the patients treated had skin rash and severe adverse reaction. Transient fever and influenza-like symptoms with combined therapy were similar to those with interferon-alpha therapy alone. Hemoglobin level decreased slightly in 9 patients (mean decrease by 5 g/L; max, 20 g/L). Reticulocytes elevated slightly. White blood cells, platelets, Bun and Cr were normal in all the patients. CONCLUSION: Our results show that combination of interferon-alpha with ribavirin for treatment of hepatitis C in children is efficacious, safe and reliable. It deserves popularization.

Antiviral Agents↗
PubMed2001

[Differential expression of cyclins D1, E and A in human breast diseases].

OBJECTIVE: To understand with greater clearness the effect of overexpression of cyclins gene and the potential implications of it for tumorgenesis in breast. METHODS: We assayed the expression of cyclins D1, E and A in different types of human breast diseases by immunohistochemical staining. RESULTS: Significant difference was seen among the malignant tumor, benign tumor and dysplasis(P < 0.001). The expressive intensity of above three kind of cyclins in malignant tumor was the highest, that in benign tumor was higher, and that in dysplasis was low. CONCLUSION: These data suggest that the expressive intensity of cyclins gene may serve as an indicator for malignant intensity of tumors. The expressive ratio difference of cyclins E and A between infiltrating ductal carcinoma and infiltrating lobular carcinoma may imply that there are different mechanisms involving the occurrence of different histological types of breast tumor.

Breast Neoplasms↗
PubMed2001

[An experimental study on bone marrow purging in vitro for patients with chronic myelogenous leukemia].

OBJECTIVE: To investigate the effect of IL-2, IFN and bcr-abl AS-ODN on bone marrow purging in vitro for patients with chronic myelogenous leukemia (CML). METHODS: By amplifying in vitro clone forming culture, and purging the bone marrow of 5 CML patients through different combined use of IL-2, IFN and bcr-abl AS-ODN, we compared the effects of 4 combined regimens. RESULTS: It was found that the suppressive effects of the 4th regimen combining IL-2 (800 U/ml), IFN (800 u/ml) and bcr-abl AS-ODN (30 micrograms/ml) on leukemia cell clone forming unit (CFU) were significantly different from the suppressive effects of the other 3 regimens (P < 0.01). With the use of the 4th regimen, the GM-CFU and L-CFU survival rates were 26.91% and 3.49% respectively (P < 0.01). CONCLUSION: The combined regimen of IL-2 (800 U/ml), IFN (800 u/ml) and bcr-abl AS-ODN (30 micrograms/ml) has good effect on selective CML bone marrow purging in vitro and can be used in clinical purging of CML bone marrow.

Bone Marrow Cells↗
PubMed2001

[Recombinant Salmonella typhimurium anticaries vaccine. II. Construction and confirmation of expressing plasmid carrying a region of S. mutans pac gene].

OBJECTIVE: The objective of this study is to construct prokaryotic expressing plasmids carrying A region of S. mutans pac gene. METHODS: The A region of pac gene was amplified by using PCR from plasmid pPC41 containing S. mutans surface protein pac gene. The new expression plasmid was constructed by using A region of pac gene and expressing plasmids pET17-b and directed cloning technique. The recombinant plasmid was identified by agarose gel electrophoresis after it was cut by using BamHI and EcoRV. RESULTS: The expressing plasmid carrying pac gene A region was acquired. CONCLUSION: The recombinant plasmid provides useful experimental materials for further research work.

Dental Caries↗
PubMed2001

[Expression of two truncated enhancin gene from Helicoverpa armigera granulosis virus in E. coli and its preliminary bioassay].

The plasmids pET-30a-Ben and pET-30a-Den which included 1.7 kd and 2.2 kb fragments of 5'-terminal of HaGV enhancin gene were obtained by cutting recombinant plasmid pET-30a-En with Bal I and Dra I respectively. Two fragments were expressed in E. coli successfully and the products were named Ben and Den respectively. The enhancement, which Ben and Den enhance the infectivity of HaNPV and Bt in 3rd larvae of Helicoverpa armigera, was studied. The results indicated that there was increase of the mortality of 10.5%-26.5% and the LT50 decrease of 0.9 d causes by adding Ben, while Den could increase the mortality by 10.2%-33.0% and decrease the LT50 by 1.2 d-1.9 d. The preliminary bioassay on Bt against Helicoverpa armigera indicated the recombinant enhancin could increase the mortality of larvae by 20.7%-35.4%, Den by 16.7%-31.5%, Ben by 11.7%-27.4%.

Animals↗
PubMed2001

[Construction of mucosal vaccine derived from HBV surface antigen epitope A and the assay of its immunogenicity].

The fusion gene of HBV(adr) surface antigen epitope and B subunit of Cholera toxin was constructed and expressed successfully in E. coli at high yield. After denaturation-renaturation process, SDS-PAGE analysis showed that most of the renatured product reassociated in a pentameric form which was the same as natural CTB. Western blot analysis indicated that the immunogenicity of HBsAg antigen epitope was conserved. Moreover, ELISA analysis of the sera of orally, intranasally and intraperitoneally immunized mice showed that the circulating IgG antibodies to HBsAg were developed. The results may be helpful for constructing the novel mucosal vaccine with high efficacy.

Animals↗
PubMed2001

[Cloning and expression of two garlic virus coat protein genes].

The coat protein(CP) genes of garlic mosaic virus(GMVc) and garlic latent virus(GLVc) isolated from garlic(Allium) plants in Tianjin, China, were amplified from an established cDNA library by PCR method and subsequently expressed in E. coli. using the pET-30a expression system. The determined sequences of GMVc and GLVc CP genes show that the complete GMVc CP gene has 867 nucleotides encoding 289 amino acids. It has 88.5% and 97.2% homology, at the levels of nucleotide and amino acid, respectively, to a reported GMV, indicating that it belongs to Potyvirus. The complete GLVc CP gene has 885 nucleotides coding for 294 amino acids. It has 73.6% and 90.9% homologous percents, in nucleotide and amino acid, respectively, compared to a previously reported GLV, suggesting that it is a member of Carlavirus. The expressed products presented in inclusion body and were analyzed by SDS-PAGE. The molecular weights of GMVc and GLVc CPs appear in 32 kD and 34 kD size, respectively, which are consistent with the deduced sizes of these two CPs. These data will be virtually significant to the further investigation of viruses infecting parlic plant, the control of garlic virus diseases and the production of virus-freed garlic plants.

Capsid Proteins↗
PubMed2001

[Overexpression of cyclin A leads to S-phase arrested apoptosis].

OBJECTIVE: This study was aimed to gain an insight into the molecular basis of S-phase arrest associated apoptosis. METHODS: The molecular expressions of Rb, cyclin A, cyclin E, CDK2 and CDC2 involved in S-phase progression were investigated by westernblot in L-2 and Br1-3pr-1 cells. Furthermore, their associated kinase activities were assayed by histone, phosphorylation. RESULTS: The results showed that ofter PALA treatment, the expression of cyclin A increased and the expression of Bcl-2 decreased in apoptosising L-2 cell as compared with those in unapoptosising Br1-3pr-1 cell, but there were no significant differences in other molecular expressions and associated kinase activities between the above-mentioned L-2 cell and Br1-3pr-1 cell arrested at S phase after PALA treatment. CONCLUSION: Cyclin A is a most potential candidate for S phase checkpoint element, and it may be able to induce the S phase arrest associated apoptosis through the Bcl-2 pathway.

Apoptosis↗
PubMed2000

Interacting fidelity defects in the replicative DNA polymerase of bacteriophage RB69.

The DNA polymerases (gp43s) of the related bacteriophages T4 and RB69 are B family (polymerase alpha class) enzymes that determine the fidelity of phage DNA replication. A T4 whose gene 43 has been mutationally inactivated can be replicated by a cognate RB69 gp43 encoded by a recombinant plasmid in T4-infected Escherichia coli. We used this phage-plasmid complementation assay to obtain rapid and sensitive measurements of the mutational specificities of mutator derivatives of the RB69 enzyme. RB69 gp43s lacking proofreading function (Exo(-) enzymes) and/or substituted with alanine, serine, or threonine at the conserved polymerase function residue Tyr(567) (Pol(Y567(A/S/T)) enzymes) were examined for their effects on the reversion of specific mutations in the T4 rII gene and on forward mutation in the T4 rI gene. The results reveal that Tyr(567) is a key determinant of the fidelity of base selection and that the Pol and Exo functions are strongly coupled in this B family enzyme. In vitro assays show that the Pol(Y567A) Exo(-) enzyme generates mispairs more frequently but extends them less efficiently than does a Pol(+) Exo(-) enzyme. Other replicative DNA polymerases may control fidelity by strategies similar to those used by RB69 gp43.

Alanine↗
PubMed2000

Effect of CO(2) and CHF(3) on the Solubilization of Protein in Reverse Micelles.

The effect of dissolved CO(2) and CHF(3) on the precipitation of bovine serum albumin (BSA) from reverse micelles of sodium bis(2-ethylhexyl) sulfosuccinate (AOT) in 2,2,4-trimethylpentane (iso-octane) has been studied at 308.15 K. It was found that BSA can be precipitated completely by CO(2) while the AOT and water remain in the iso-octane continuous phase. This opens up a possibility for recovery of protein solids directly from reverse micellar solutions. CHF(3) is also an effective agent for precipitation of BSA in the reverse micelles when the expansion coefficient of CHF(3) exceeds 0.4. However, the condition required for complete removal of the BSA using CHF(3) results in some precipitation of AOT and water from the solution. Copyright 2000 Academic Press.

Journal Article↗
PubMed2000

The effect of preoperative transcatheter hepatic arterial chemoembolization on disease-free survival after hepatectomy for hepatocellular carcinoma.

BACKGROUND: Although surgical resection has produced better results than other therapies for local control of hepatocellular carcinoma (HCC), the long term results have not been satisfactory because of a low disease-free survival rate. The effects of preoperative transcatheter arterial chemoembolization (TACE) on improving disease-free survival of HCC after hepatectomy has remained controversial. METHODS: The current study was retrospective survey of 1725 patients who had hepatectomy for HCC between January 1990 and December 1995 and had follow-up data for 1457 cases. The follow-up rate was 84.5%. The significant prognostic factors were analyzed using a Cox proportional hazards survival model, and the disease-free survival was calculated by Kaplan-Meier estimation. Among 1457 cases, 120 patients underwent preoperative TACE and were divided into a one time TACE group, over two times TACE group, an effective group, and ineffective group. RESULTS: Multivariate analyses revealed significant prognostic factors as follows: preoperative TACE number, preoperative TACE effect, preoperative lesion number, intraoperative tumor thrombus, tumor size, tumor gross type, daughter nodules, vascular invasion, and postoperative alpha-fetoprotein value. Kaplan-Meier estimation showed that the 5-year disease-free survival rates of the over two times group, the one time group, and no TACE group were 51.0%, 35.5%, and 21.4%, respectively, and that the mean disease-free survival times of the three groups were 66.4, 22.5 and 12.5 months, respectively. The effective group had a 5-year disease-free survival rate of 56.8%, with a mean time of 90.1 months. CONCLUSIONS: Effective preoperative TACE may be one of the best methods, which can be clinically performed at present, for resectable HCCs including small HCCs for improving disease-free survival after hepatectomy. According to tumor size, range, location, hepatic function, and TACE effect, TACE can be performed 2-4 times preoperatively within 6 months.

Adolescent↗
PubMed2000

Effect of resveratrol on intimal hyperplasia after endothelial denudation in an experimental rabbit model.

The ability of resveratrol to inhibit vascular intimal thickening was tested in an experimental model in which endothelial denudation was performed in the normal rabbit iliac artery. Resveratrol (2 approximately 4mg/ kg/d) was administered intragastrically for 5 weeks beginning 1 week before denudation. At the higher concentration of resveratrol, the intimal hyperplasia of injured vascular wall was effectively inhibited; the intimal proliferation index also was significantly less than that in the untreated control group (0.28 +/- 0.07 vs 0.41 +/- 0.13, respectively, p<0.01); the relative luminal area increased from 0.38 +/- 0.06 in the untreated control group to 0.53 +/- 0.10 in the resveratrol treatment group (p < 0.001); and the count of smooth muscle cells in the thickened intima was statistically significantly reduced in the high dose resveratrol treatment group than that in the untreated group (1,115 +/- 510 vs 1,796 +/- 963, respectively, p < 0.05). Resveratrol added to the culture media of cultured rabbit vascular smooth muscle cells inhibited DNA synthesis in a dose-dependent manner. These results showing that resveratrol is capable of inhibiting intimal hyperplasia of injured artery raise the possibility that this polyphenol might have clinical potential in prevention and treatment of restenosis after angioplasty.

Animals↗
PubMed2000

Murine hematopoietic stem cell characterization and its regulation in BM transplantation.

Using 5-color fluorescence-activated cell sorting, we isolated a subset of murine pluripotent hematopoietic stem cells (PHSC) with the phenotype Lin(-) Sca(+) kit(+) CD38(+) CD34(-) that appears to fulfill the criteria for most primitive PHSC. In the presence of whole bone marrow (BM) competitor cells, these cells produced reconstitution in lethally irradiated primary, secondary, and tertiary murine transplant recipients over the long term. However, these cells alone could not produce reconstitution in lethally irradiated recipients. Rapid proliferation of these cells after BM transplantation required the assistance of another BM cell subset, which has the phenotype Lin(-) Sca(+) kit(+) CD38(-) CD34(+).

ADP-ribosyl Cyclase↗