Biomedical subjects

Hong Ren

Publications and source records attributed to Hong Ren.

83 records · Page 5Linked to original sources

PubMed2002

I-kappa B kinase beta is critical for B cell proliferation and antibody response.

The NF-kappaB proteins are critical in the regulation of the immune and inflammatory response. Stimulation of the NF-kappaB pathway leads to increases in I-kappaB kinase beta (IKKbeta) kinase activity to result in the enhanced phosphorylation and degradation of I-kappaB and the translocation of the NF-kappaB proteins from the cytoplasm to the nucleus. In this study, a dominant-negative IKKbeta mutant expressed from the IgH promoter was used to generate transgenic mice to address the role of IKKbeta on B cell function. Although these transgenic mice were defective in activating the NF-kappaB pathway in B cells, they exhibited no defects in B lymphocyte development or basal Ig levels. However, they exhibited defects in the cell cycle progression and proliferation of B cells in response to treatment with LPS, anti-CD40, and anti-IgM. Furthermore, selective defects in the production of specific Ig subclasses in response to both T-dependent and T-independent Ags were noted. These results suggest that IKKbeta is critical for the proliferation of B cells and the control of some aspects of the humoral response.

Animals↗

PubMed2002

Inhibition of N-methyl-D-aspartate receptors by straight-chain diols: implications for the mechanism of the alcohol cutoff effect.

n-Alkanol inhibition of N-methyl-D-aspartate (NMDA) receptors exhibits a "cutoff" effect: alcohols with up to eight to nine carbon atoms inhibit the receptor, whereas larger alcohols do not. This phenomenon was originally proposed to result from size exclusion; i.e., alcohols above the cutoff are too large to bind to an amphiphilic site on the receptor. In the present study, 1,Omega-diols with 3 to 14 carbon atoms inhibited NMDA-activated current in Chinese hamster ovary and human embryonic kidney 293 cells transiently expressing NR1 and NR2B NMDA receptor subunits. Results of fluctuation analysis experiments were consistent with a similar mechanism of inhibition of NMDA-activated current by alcohols and diols. The average change in apparent energy of binding of the diols caused by addition of a methylene group was 2.1 kJ/mol, which is consistent with an important role of hydrophobic interactions. Because 1,Omega-diols with 9 to 14 carbons inhibited NMDA-activated current, despite having molecular volumes exceeding that at the cutoff point for 1-alkanols, a size exclusion mechanism seems inadequate to explain the cutoff effect. A disparity in hydrophobicity values at the cutoff for alcohols and diols, however, revealed that hydrophobicity could also not entirely explain the cutoff phenomenon. From these results, it seems that the cutoff effect on NMDA receptors results primarily from the inability of long-chain alcohols to achieve adequate concentrations at their site of action due to low aqueous solubility, although other factors may also contribute to the effect.

Animals↗

PubMed2002

Effects of electroporation on primary rat hepatocytes in vitro.

AIM: To investigate the effects of electroporation on primary rat hepatocyte and to optimize the electroporation conditions introducing foreign genes into primary hepatocytes. METHODS: A single-pulse procedure was performed at low voltage (220-400 V) but with high capacitance (500-950 microF). Hepatocytes were divided into 4 groups according to the electroporation conditions: group I, 220 V and 500 microF; group II, 220 V and 950 microF; group III, 400 V and 950 microF,and group IV. The control group was freshly isolated hepatocytes and directly cultured under the same conditions as those of electroporation groups. The effects of electroporation on primary rat hepatocytes were detected by trypan blue exclusion (TBE) and MTT analysis. Besides, albumin (Alb), alanine transaminase (ALT) and lactate dehydrogenase (LDH) in the supernatants of cultured hepatocytes were measured by biochemical assay. RESULTS: Between day 1 and day 15 after incubation, primary rat hepatocytes of each electroporation group appeared normal, being the same with those of control group. TBE staining showed that slight hepatocyte damage and high survival rate were found in the electroporation groups and the control group. Cultured for 3, 7, 11 and 15 days, hepatocyte viability was approximately 92.6+/-2.5 %, 89.5+/-3.3 %, 82.0+/-3.5 % and 74.3+/-1.2 %, respectively. MTT analysis indicated that the viabilities of hepatocytes had no significant difference between each electroporation group, and those were similar to that of control group. At the 36th hour after electroporation, Alb, ALT and LDH in the supernatants of control group were 5.3+/-0.1 g x L(-1), 183.7+/-8.4 nkat x L(-1) and 896.8+/-58.5 nkat x L(-1); those of group II were 5.7+/-0.1 g x L(-1), 215.4+/-16.7 nkat x L(-1) and 1063.8+/-51.8 nkat x L(-1); and those of group III were 5.8+/-0.2 g x L(-1), 217.1+/-8.4 nkat x L(-1) and 1063.8+/-10.0 nkat x L(-1). Statistically, the proteins of group II and group III were significantly higher than those of control group (P<0.05), whereas the protein production of group I, Alb, ALT and LDH were 5.3+/-0.2 g x L(-1), 205.4+/-3.3 nkat x L(-1) and 1035.4+/-116.9 nkat x L(-1), were similar to those of control group. At the same time, TBE and MTT analysis indicated that there was no significant cell viability difference between electroporation groups and control group. CONCLUSION: This single-pulse electroporation procedure performed at low voltage (220-400 V) but with high capacitance (950 microF) is one of the optimal choices to introduce foreign genes into primary rat hepatocyte.

Animals↗

PubMed2002

Multivariate statistical analysis of clinicopathologic factors influencing survival of patients with bile duct carcinoma.

AIM: To evaluate the influence of various clinicopathologic factors on survival of patients with bile duct carcinoma after curative resection. METHODS: A retrospective analysis was made for 86 cases of bile duct carcinoma treated from January 1981 to September 1995. Fifteen clinicopathologic factors possibly influencing survival were selected. Independent variables were first analyzed by univariate methods. Survival for variable was estimated by the method of Kaplan and Meier. The variables that were statistically significant by univariate analysis were included in a multivariate analysis, which were confirmed using the Cox stepwise proportion hazard model with the help of SPSS 10.0 for Windows software. RESULTS: The overall cumulative survival rate was 72.6 % at 1 year, 32.4 % at 3 years, and 18.7 % at 5 years. The results of univariate analysis showed that the major significant prognostic factors influencing survival of these patients were histological type of lesion, lymph node metastasis, pancreatic invasion, duodenal invasion, perineural invasion, macroscopic vessel involvement, resected surgical margin and depth of cancer invasion (P=0.02, 0.02, 0.004, 0.005, 0.01, 0.43, 0.03 and 0.04). Age, sex, location of tumor, size of tumor, macroscopic type of lesions, hepatic metastasis, and hepatic invasion were not significantly associated with prognosis (P>0.05). Pancreatic invasion, perineural invasion and lymph node metastases were the three most important prognostic factors by multivariate analysis using the Cox proportional hazards model. CONCLUSION: Pancreatic invasion, perineural invasion and lymph node metastases are the most important prognostic factors for bile duct carcinoma after curative resection.

Adult↗

PubMed2002

[Study on the natural history of chronic hepatitis B].

OBJECTIVE: By clarifying the natural history of chronic hepatitis B, to evaluate its long-term therapeutic outcome, antiviral drugs efficacy and economic significance. METHODS: A cohort of 183 (mean age of 31.75?.03 years, male/female ratio: 152:31) chronic hepatitis B patients with biopsy-proven and 247 cases of general population as control were followed up by retrospective cohort study. The follow-up time was 11.81?.08 years. This study was focused on long-term clinical outcome including the rate of liver cirrhosis, hepatocellular carcinoma and death, the long-term effect of antiviral drugs and prognostic factors. RESULTS: In chronic hepatitis B patients, 22 (12.02%) developed liver cirrhosis, 12 (6.56%) hepatocellular carcinoma, and 20 (10.93%) died. The cumulative survival probabilities were 97.27%, 91.62%, and 84.47% in 5, 10, and 15 years, respectively. The cumulative probabilities of HCC were 0.00%, 3.19%, and 11.56% in 5, 10, and 15 years, respectively. In 247 control subjects, 6 (2.43%) died, none of them developed cirrhosis or HCC. The rates of death, liver cirrhosis, and HCC in hepatitis B patients were markedly different (P<0.005) compared with controls. The overall mortality of hepatitis B patients was 4.50 folds of the general population. Cox multiple regression analysis showed that old age, severe histological injury, and the positive HBeAg were closely related to liver cirrhosis, while old age, severe histological injury, and male were major factors leading to death. The independent variable of predicted HCC was not found. CONCLUSIONS: The long-term outcome of hepatitis B is poor.

Adolescent↗

PubMed2002

[Construction of eukaryotic expression plasmids inserting HBsAg gene and DNA immunization responses to HBsAg in mice].

OBJECTIVE: To study the HBsAg transient expression in HepG2 or COS-7 cells with eukaryotic expression plasmids inserting HBsAg gene (pCI-S and pcDNA3.1-S) and the efficacy of naked DNA immunization in mice. METHODS: Firstly, the recombinant plasmids of pCI-S and pcDNA3.1-S were constructed by the cloning technique and the accuracy of these constructs was confirmed by restriction enzyme digestion and DNA sequencing. Secondly, plasmids of pCI-S and pcDNA3.1-S were transferred into HepG2 and COS-7 cells, respectively by means of cationic liposome. HBsAg transient expression was assayed by ELISA in cell culture supernatants and cell lysates. Thirdly, plasmids were injected into quadriceps muscles of BALB/C mice and serum samples were obtained from individual immunized or control mice 4 weeks after injection and boost injection, respectively. Anti-HBs were assayed in mice sera by ELISA. HBsAg-specific CTL responses of spleen cells from immunized mice were tested by the LDH method. RESULTS: Plasmids of pCI-S and pcDNA3.1-S allowed HBsAg transient expression in cell culture supernatants and cell lysates of HepG2 or COS-7 cells. Intramuscular immunization of BALB/C mice with plasmids of pCI-S or pcDNA3.1-S elicited the antibody and cytotoxic T lymphocyte responses to HBsAg. CONCLUSIONS: The vectors used in this study are effective to induce prime antibody and HBsAg-specific-cytotoxic T lymphocyte responses to HBsAg in mice after intramuscular immunization.

Animals↗

PubMed2002

[Transient expression of fusion protein with a chimeric HBsAg-HSP70 construct in HepG2 cells].

OBJECTIVE: To investigate transient expression of fusion protein with a chimeric HBsAg-HSP70 construct in HepG2 cells. METHODS: Enkaryotic expression plasmids inserted HBsAg gene or chimeric HBsAg-HSP70 gene were prepared and transfected into HepG2 cells by means of cationic liposome. mRNA were detected by RT-PCR and proteins expressed in the cells were detected by immunocytochemistry 48 hours later. HBsAg in cultured supernatants and cell lysates were assayed by ELISA. RESULTS: Fusion protein (HBsAg-HSP70) transient expression in HepG2 cells were confirmed by RT-PCR, immunocytochemistry or ELISA, but fusion protein was not assayed in cell cultured supernatants by ELISA. CONCLUSIONS: Transfection of HepG2 cells with a chimeric HBsAg-HSP70 construct leads to express fusion protein, but it does not secrete into cell cultured supernatants.

Bacterial Proteins↗

PubMed2002

[An in vitro model of hepatitis B virus gene replication and expression in primary rat hepatocytes transfected with circular viral DNA].

OBJECTIVE: To establish an in vitro model of hepatitis B virus (HBV) replication and expression in primary rat hepatocytes (PRH) transfected with circular viral DNA for further study on the interaction of HBV with hepatocytes. METHODS: Circular viral DNA containing complete HBV genome were transfected into PRH by electroporation (transfected group, about 4mug of circular viral DNA/1 10(7)cells). From day 1 to day 10 after transfection, HBsAg and HBeAg in the supernatants and lysates of PRH were measured with IMX system. HBcAg was assayed with western blotting, immunol dot blotting and immunocytochemistry. Meanwhile, HBV S-mRNA and X-mRNA were tested with RT-PCR, and replicative intermediates of HBV DNA were analyzed by southern blotting and dot blotting. Moreover, Transmission electron microscopy was used if viral particles were produced in transfected rat hepatocytes. PRH electroporated only was used as control group. RESULTS: (1) Viral antigen production in transfected rat hepatocytes: HBsAg in cell lysates was positive. P/N values ranged from 4.83 to 85.69, and could be maintained for 10 days after transfection. The average P/N values was 18.239 27.459. Whereas, HBsAg was negative in the supernatants of transfected group (P/N values, negative<2.1). HBeAg in the supernatants and lysates of transfected hepatocytes all was negative (P/N values<2.1) during 10 days following transfection. HBcAg was only found positive in transfected hepatocytes by immunol dot blotting. (2) Detection of viral transcripts: transcription of HBV DNA was investigated by preparing total RNA from rat hepatocytes 2 days after transfection and looking for S-mRNA and X-mRNA by RT-PCR. Results showed S-mRNA positive, X-mRNA negative. (3) HBV DNA replication analysis: intracellular total DNA was extracted 2 days after transfection and analysed by southern blotting. All replicative DNA intermediates, including relaxed circular (rcDNA), covalently closed circular (cccDNA), and single-stranded (ssDNA) linear HBV DNA forms, were indicated. Dot blotting showed intracellular HBV DNA positive in transfected group during 10 days after transfection. However, viral particles were not found in transfected hepatocytes during 3 days after transfection. CONCLUSIONS: Circular HBV DNA transfected into primary adult rat hepatocytes could obtain continuous replication and stable expression of HBV surface antigen. This in vitro model has high reproducibility and stability, and is useful for directly studying the interaction of HBV with hepatocytes.

Animals↗

PubMed2002

[Relationship between the different replication status of HBV and mutations in core promoter in mother and children infected by mother-to-infant transmission].

OBJECTIVE: To understand the relationship between the different replication status of HBV and mutations in core promoter in mother and child infected by mother-to-infant transmission. METHODS: Core promoter was amplified by PCR and cloned into pGEM-T vector with T-A cloning technique. The recombinant plasmid pGEM-PreS/S was confirmed by digestion with restriction enzyme Apa I and Sac I. Two clones were selected to sequence each patient. RESULTS: Every pair of mother and child had same serotype and genotype and the homology of nucleotides encoding "a" determinant was 98 to 100%. The number of mutations in core promoter in patients with high replication status was more than that of low replication status. Mutations were distributed in BCP and Kunitz-type serine protease inhibitor region mainly. This difference was not associated with mother or child. CONCLUSIONS: The different replication status of HBV is caused by mutations in core promoter in mother and child infected by mother-to-infant transmission and seems not to be associated with the development status.

Child↗

PubMed2002

[Study on induction of dendritic cells from myeloid leukemia cell lines and their antitumor immune function].

Dendritic cell (DC) plays a key role in antitumor immune response. However, there is a deficiency of DC function in the majority of leukemia patients. It is a novel idea that expanding DC in vitro and enhancing their antitumor immune function and DC-based tumor vaccines may be used as an efficient immune therapy for leukemia. In the project, the condition to induce DC from myeloid leukemia cell lines and its anti-leukemia response were investigated. HL-60, K562 and THP-1 cells were cultured with various combinations of cytokines for inducing DC. The morphologic features were analyzed with optical and electron microscopy. The phenotype of DC was detected by FCM with CD1a, CD40, CD80, CD86, HLA-A, B, C and HLA-DR monoclonal antibodies. The ability of DC stimulating lymphocyte proliferation was observed by allo-mixed lymphocyte reaction using (3)H-TdR incorporation. Cytotoxicity assay was measured by (51)Cr-release method. The level of IL-12 and IFN-gamma in supernatant of DC culture was measured by ELISA. It was proved that the DCs derived from K562, HL-60 and THP-1 cells showed a typical morphology of dendritic cell. The induced cells expressed the surface differentiation antigens of DC. A high expression of phenotypes was found in HL-60-DC and THP-1-DC stimulated by GM-CSF + IL-4 + TNF-gamma and K562-DC with GM-CSF + IL-4 + IL-12. The DCs from the 3 leukemia cell lines stimulated allo-MLR and CTL reaction strongly. Different contents of IL-12 were detected in the supernatants of DC culture and IFN-gamma in the coculture of DC and blood mononuclear cells. It is concluded that the myeloid leukemia cells are able to be induced DCs by cytokines in vitro. The different leukemia cells need different cytokines and cultural conditions. DCs derived from leukemia cells express phenotype of antigen-presenting cells. They have the ability of stimulating T lymphocyte proliferation and inducing CTL reaction to clear leukemia cells, and the DCs secrete IL-12 and increase secretion of IFN-gamma by T cells.

Antigens, CD↗

PubMed1998

Sequencing of PCR amplified HBV DNA pre-c and c regions in the 2.2.15 cells and antiviral action by targeted antisense oligonucleotide directed against sequence.

AIM:To study the specific inhibition of HBV gene expression by liver-targeting antisense oligonucleotide (ASON) directed against pre-c and cregious in a sequence specific manner.METHODS:According to the result of direct sequencing of PCR amplified products, a 16 mer phosphorothioate analogue of the antisense oligonucleotide (PS-ASOn) directed against the HBV U-5-like region was synthesized and then linked with one live-targeting ligand, the galactosylated poly-L-lysine.Their effect on the expression of HBV gene was observed using the 2.2.15 cells.RESULTS:HBV DNA in the 2.2.15 cells was from HBV with surface antigen subtype ayw 1 by sequencing so that antisense oligonucleotides could bind specifically to the target sequence through base piring. Under the same experimental conditions, the inhibitory rates of PS-ASON to HBsAg and HBeAg were 70% and 58% at a concentration of 10&mgr;mol/L, while by ligand-PS-ASON they were 96% and 82%, the amount of HBV DNA in cultured supernatant and cells was reduced significantly. An unrelated sequence oligonucleotide showed no effectiveness. All the oligonucleotides had no cytotoxicity.CONCLUSION:Antisense oligonucleotides complexed by the liver-targeting ligand can be targeted to cells via asialoglycoprotein receptors, resulting in supecific inhibition of HBV gene expression and replication.

Journal Article↗