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Biomedical subjects

H Guo

Publications and source records attributed to H Guo.

At least 163 records · Page 9Linked to original sources
PubMed1998

Regulation of beta-chemokine mRNA expression in adult rat astrocytes by lipopolysaccharide, proinflammatory and immunoregulatory cytokines.

Astrocytes constitute a part of the blood-brain barrier. Chemokine expression by astrocytes may contribute to leucocyte infiltration within the central nervous system (CNS) during inflammation. To investigate factor(s) regulating chemokine expression by astrocytes, we studied the induction of beta-chemokine mRNA expression in adult rat astrocytes. Astrocyte-derived monocyte chemoattractant protein- (MCP-1), RANTES, macrophage inflammatory protein (MIP)-1alpha and MIP-1beta mRNA were induced by interferon-gamma (IFN-gamma). Tumour necrosis factor-alpha (TNF-alpha) induced MCP-1, RANTES and MIP-1beta mRNA expression, and lipopolysaccharide (LPS) induced MCP-1, MIP-1alpha and MIP-1beta mRNA expression in astrocytes. LPS-induced MCP-1, MIP-1alpha and MIP-1beta mRNA expression by astrocytes was antagonized by transforming growth factor (TGF)-beta1 and interleukin (IL)-10. TGF-beta1 and IL-10 also down-regulated MCP-1 and RANTES mRNA expression induced by TNF-alpha. IL-10, but not TGF-beta1, inhibited MIP-1beta mRNA expression induced by TNF-alpha. The results of this in vitro study suggest that beta-chemokine mRNA expression by adult rat astrocytes can be induced by LPS or proinflammatory cytokines, while regulatory cytokines, such as TGF-beta1 and IL-10, down-regulate astrocyte-derived beta-family chemokine mRNA expression induced by LPS, IFN-gamma and TNF-alpha. Further study of CNS chemokines will enhance our understanding of leucocyte recruitment to the CNS and suggest therapeutic strategies for neurological disorders.

Animals↗
PubMed1998

[Membrane guided tissue regeneration in the treatment of bone defect].

Membrane guided tissue regeneration is new biological concept. The basic theory of this concept includes the belief that during the healing process of wound, the different cells will show different speed of cell migration and regeneration in the wound. If an appropriate membrane being placed to form a mechanical barrier, so that only the needed cells can grow into that area and prevent others from going in, thus resulting in the creation of a guided area where the needed cells can undergo proliferation and differentiation under protection in completing an ideal tissue regeneration and repair. In this article, the experimental researches on the application of membrane guided tissue regeneration in the repair of tubular bone defects, skull defects and faciomaxillary defects were reviewed from literatures, and the degradable and non-degradable materials were introduced, particularly. The pros and cons of this method and the materials were evaluated. It is believed that this technique will push forward the progress in bone biology and reconstructive surgery.

Animals↗
PubMed1998

[Effect of EBV latent membrane protein 1 gene isolated from human nasopharyngeal carcinoma cell line SUNE on the growth of immortalized epithelial cells].

OBJECTIVE: To study the effect of EBV latent membrane protein (LMP1) gene isolated from human nasopharyngeal carcinoma cell line SUNE on the growth of epithelial cells and the role of LMP1 in the genesis of nasopharyngeal carcinomas. METHODS: EBV LMP1 gene eukaryotic expression plasmid was transfected into human embryo kideney epitheial cells. Expression of LMP1 protein in the transfected cells was detected. Dynamic cell growth status, growth rate, ability of colony formation in soft agar and the tumorigenicity of the transfected cells in nude mice were studied. RESULTS: The LMP1 gene transfected cells grew vigorously and rapidly, lost contact inhibition, formed more colonies in soft agar, developed tumors in nude mice. CONCLUSION: LMP1 gene could alter the biological behaviours of epithelial cells, promote cell proliferation and transformation, and endows the transfected cells with growth characteristics like tumor cells.

Animals↗
PubMed1998

Extended frontotemporal epidural approach to cavernous sinus: surgical anatomy and technique.

OBJECTIVE: To investigate the surgical technique of trans-frontotemporal extended epidural approach to the cavernous sinus. METHODS: A microsurgical study on the exposure and dissection of the cavernous sinus and its surrounding structures on cadavers was performed via an extended epidural approach with frontotemporal skull-base craniectomy. RESULTS: The extended epidural approach offered an appropriate exposure of the cavernous sinus with minimal brain retraction and nerve damage. CONCLUSIONS: The extended frontotemporal epidural surgical approach is superior to the routine intradural or combined epi- and intradural approaches. It is suitable for most of the cavernous sinus surgeries.

Brain Neoplasms↗
PubMed1998

[Apoptosis induced by adenovirus-mediated wild-type p53 expression in human pancreatic cancer cells].

OBJECTIVE: To investigate the biological effects of wtp53 expression on the growth rate and apoptosis of human pancreatic carcinoma. METHODS: The Ad5CMVwtp53 a recombinant replication-deficient adenoviral vector containing a human CMV promoter, a human wild-type p53 and the SV40 polyadenylation signal was amplified in 293 packaging cells. The pancreatic carcinoma cell line (PC-2), carrying a mutation of p53 gene at codon 240, was transfected using Ad5CMV wtp53 and the control adenoviral vector Ad5pXJ. RESULTS: The cells transfected with Ad5CMV wtp53 showed that presence and expression of wtp53 gene were demonstrated using PCR and immunoprecipitation, that growth rate and 3H-TdR incorporation rate were decreased. The restoration of wtp53 encoded protein in PC-2 cells induced apoptosis assessed by in situ TUNEL apoptosis, flow cytometry, DNA agarose gel electrophoresis analyses, whereas noninfected cells or the cells infected with control virus didn't show these changes. CONCLUSION: Replication-deficient adenoviral vector is an efficient vector in transferring wtp53 gene and antitumor therapy using the p53 gene is a valuable method in inhibiting pancreatic cancer cells growth by inducing apoptosis.

Adenoviruses, Human↗
PubMed1998

Inhibiting effect of murine double minute-2 oncogene on apoptosis induced by retroviral-mediated wild-type p53.

OBJECTIVE: To investigate the effects of wild-type p53 (wtp53) on inducing apoptosis by restoring wtp53 expression in pancreatic adenocarcinoma cell line (PC-2) which contains mutant p53, and the interaction between murine double minute-2 (MDM2) and wtp53 in pancreatic adenocarcinoma. METHODS: A recombinant retroviral vector expressing wild-type p53 was constructed and packaged by packaging cell line PA317 cells using calcium phosphate coprecipitation method. The supernatant of the packaged cells PA317 was used to transfect the pancreatic carcinoma cell line (PC-2), then a transformed cell line PC-2/swtp53 was established. The recombinant vector pCMV-MDM2 was transduced into PC-2/swtp53 cell line by lipofectin-mediated method, a double transfected cell line (PC-2/swtp53/pCMV-MDM2) was formed. To determine the integration and expression of exogenous wtp53 gene in the transfected cells, polymerase chain reaction (PCR), Western blot and immunoprecipitation analyses were performed. Apoptosis was analyzed by means of flow cytometry, in situ terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) analysis and DNA agarose gel electrophoresis. RESULTS: Transduction with the retroviral vector resulted in integration and expression of wtp53 gene in host cells. The apoptotic cells in PC-2/swtp53 and PC-2/swtp53/pCMV-neo cell lines were 12.1%-12.9%, while the double transfected cell line, PC-2/swtp53/pCMV-MDM2, showed less (3.2%) apoptotic cells than its parent cell lines. CONCLUSIONS: Restoration of expression of wild-type p53 with a retroviral vector can increase programmed cell death of pancreatic adenocarcinoma cells (PC-2) containing mutant p53. The overexpression of MDM2 protein has a negative regulating role in wtp53-induced apoptosis in PC-2 cell.

Adenocarcinoma↗
PubMed1998

[HIM82 protects RBC from the ROS damage produced by activated PMN].

OBJECTIVE: To investigate the protection of RBC from ROS damage produced by activated PMN with McAb-HIM82. METHODS: RBC was injured by ROS produced from PMN activated with PMA and the injury was antagonised by adding HIM82(30 micrograms/ml) to the medium with PMN. RESULTS: Comparing antagonitic group with injured group, the activity of AchE on RBC membrane after adding HIM82 was recovered from (71.36 +/- 22.15)% to (87.66 +/- 14.78)% (n = 6 P < 0.001). The proportion of MDA was decreased from (52.42 +/- 20.63)% to (23.81 +/- 12.4)%(n = 9 P < 0.001); the hemolysis rate was decreased from (80.76 +/- 20.23)% to (66.30 +/- 7.08)% (n = 6 P < 0.05); CONCLUSIONS: The result showed that the McAb HIM82 could protect RBC from injury by down-reguration of ROS level in activated PMN. It could help to establish a newer approach to study the regulation effect of McAb HIM82 on ROS production from PMN actived with relerant cytokines as well as mediators.

Acetylcholinesterase↗
PubMed1998

[Quantitative study on synergistic effect of radix astragali A6 and acyclovir against herpes simplex virus type I by polymerase chain reaction].

OBJECTIVE: To evaluate the synergistic effect of Radix Astragali A6(A6) and acyclovir (ACV) in antagonizing herpes simplex virus type I (HSV1). METHODS: The synergistic effect was measured by competitive polymerase chain reaction (PCR) and compared with that measured by traditional cytopathic effect (CPE) inhibition method. RESULTS: The minimum inhibition concentration of A6, ACV and A6 + ACV measured by PCR was 1.88 mg/ml, 3.37 micrograms/ml and 0.47 mg/ml + 0.84 microgram/ml respectively, while measured by CPE, it was 6.25 mg/ml, 50 micrograms/ml and 0.94 mg/ml + 12.5 micrograms/ml respectively. The fractional inhibitory combined indexes were all less than 0.5, which is an indication of obvious co-synergistic effect. CONCLUSION: The quantitative PCR is an effective method of screening antiviral drugs. The inhibitory action of A6 and ACV on HSV1 revealed mainly at the replicative stage of viral proliferation cycle.

Acyclovir↗
PubMed1998

[Murine Doube Minute 2 oncogene inhibited apoptosis induced by retroviral-mediated wild-type p53].

OBJECTIVE: To investigate the interaction between Murine Doube Minute 2 (MDM2) oncogene and p53 gene in the evolution of apoptosis in pancreatic carcinoma. METHODS: A recombinant retroviral vector expressing wild-type p53 was constructed and packaged by packaging cell line PA317 cells using calcium phosphate coprecipitation method. The viral supernatant of the packaged vector was used to transfect the pancreatic carcinoma cell line(PC-2), a transformant cell line PC-2/swtp53 was then established. A recombinant vector pCMV-MDM2 was transduced into PC-2/swtp53 cells by lipofectin-mediated method, a double transfected cell line PC-2/swtp53/pCMV-MDM2 was formed. RESULTS: By means of flow cytometry, in situ TdT analysis and DNA agarose gel electrophoresis, an increase of apoptosis was demonstrated in PC-2/swtp53 cell line (> 12%), whereas apoptosis was decreased in PC-2/swtp53/pCMV-MDM2 cell line (3.2%). CONCLUSIONS: MDM2 oncogene can inhibit apoptosis induced by wild-type p53 gene in pancreatic carcinoma.

Adenocarcinoma↗
PubMed1998

[The effect of adenovirus-mediated wild-type p53 expression on the growth of human pancreatic carcinoma cell line cells].

OBJECTIVE: To evaluate the effect of the wild-type p53(wtp53) expression on the growth of pancreatic carcinoma cell line. METHODS: A recombinant adenovirus vector (E1 minus)-Ad5CMVwtp53 expressing human wild-type p53 was constructed, the vector contained a human CMV promoter, a human wild-type p53 cDNA and SV40 polyadenylation signal. The Ad5CMVwtp53 and control adenoviral vector Ad5pXJ were amplified in 293 packaging cells and were used to transfect human pancreatic carcinoma cell line (PC-2). The presence and expression of wtp53 in the cells transfected with Ad5CMVwtp53 were confirmed by PCR and Northern blot. RESULTS: The transformant cells exhibited growth retardation and lost the ability to form colony in soft agar. CONCLUSIONS: The restoration of wtp53 expression in human pancreatic carcinoma cells which express endogenous mutant p53, can suppress the growth and partly reverse the malignant phenotype of pancreatic carcinoma cells.

Adenocarcinoma↗
PubMed1998

[Preserving remnant liver function after major hepatic vein occlusion].

OBJECTIVE: To observe the pathological changes of the remained hepatic lobe after major hepatic vein (MHV) occlusion. METHOD: Seventy-eight rats were randomly divided into the control group, the ligation group of segmental hepatic vein, the stricture group of left MHV, and the ligation group of left MHV. The pathology, hepatic microcirculation and hemodynamic changes of the involved hepatic lobe of MHV occlusion were dynamically determined. RESULT: Necrosis occurred in the hepatocytes at the first postoperative day in the ligation group of MHV. Extensive collaterals between the hepatic veins and the portal veins appeared in the periphery of involved liver lobe in the stricture group of MHV. The levels of endotoxin and TXB(2)/6-Keto-PGF1alpha in the blood of portal vein obviously increased in the ligation group of MHV and also increased in the stricture group of MHV. The levels of endotoxin and TXB(2)/6-Keto-PGF1alpha in the blood of portal vein in the ligation and stricture group of MHV were apparently higher than those in the ligation group of segmental hepatic vein and in the control group. CONCLUSION: The involved liver tissue can not tolerate complete MHV occlusion. The hepatic tissue lacking of MHV drain not only loss its function, but also cause endotoxemia and disorder of hepatic microcirculation. The involved hepatic lobe after the MHV ligation should have been resected at the same time.

6-Ketoprostaglandin F1 alpha↗
PubMed1998

[Parameters of arterial occlusion during intracranial aneurysm surgery].

OBJECTIVE: To evaluate parameters, owing to temporary and/or permanent intraoperative arterial occlusion, could be related to the postoperative development of ischemic injury. METHOD: During 3-year period between October 1994 and March 1997, 27 patients with intracranial aneurysm were operated on with the aid of temporary and/or permanent arterial occlusion. Continuous intraoperative monitoring lCBF of the territories undergoing occlusion was carried out using LDF. Univariate analysis was used to study the relationship between the study variable and cerebral infarction. These variables included patient age, sexuality, aneurysm size, preoperative Hunt and Hess grades, LDF baseline value, LDF value following arterial occlusion and release of occlusion, the duration of arterial occlusion, the numbers of occlusive episodes, and the degree of arterial occlusion. Student's t-test was used for comparison of continuous variable such as age, and chi-square analysis was used to test the association of categorical variables. RESULT: The LDF value following arterial occlusion or residual lCBF, the duration of arterial occlusion, the numbers of occlusive episodes, and the occlusive degree were found to be significantly related to the postoperative development of ischemic injury. CONCLUSION: The residual lCBF and collateral circulation following arterial occlusion can be evaluated using LDF monitoring. When residual lCBF is more than 50 per cent of the baseline and the duration of arterial occlusion less than 20 minutes, temporary arterial occlusion is safe and does not develop postoperative ischemic injury.

Adolescent↗
PubMed1998

[Studies on pyridonecarboxylic acids as antibacterial agents. XIV. Synthesis and structure-activity relationships of 7,8-disubstituted-1-cyclopropyl-6-methyl-1,4-dihydro-4-oxo-3-quinoline carboxylic acids].

Eighteen pyridonecarboxylic acids, characterized by a methyl group at the C6-position instead of the usual fluorine atom, cyclopropyl at the N1-position, substituted amino groups at the C7-position, and some substituted groups (hydrogen, chlorine, nitro and amino) at the C8-position, were synthesized. The in vitro antibacterial activity of these compounds were tested, and the structure-activity relationships were also discussed. The results of the study showed that the activity of compounds 22 and 24 were less potent than that of ciprofloxacin against S. aureus, S. epidermidis, E. coli and P. aeruginosa, while they were 2-100 times more potent than ciprofloxacin against K. pneumoniae, S. marcescens, A. calcoacetous, E. aerogenes, S. typhi and S. typhimurium.

Anti-Infective Agents↗
PubMed1998

Effect of artemether on hexokinase, glucose phosphate isomerase and phosphofructokinase of Schistosoma japonicum harbored in mice.

AIM: To study the effect of artemether (Art) on hexokinase (HK), glucose phosphate isomerase (GPI) and phosphofructokinase (PFK) of Schistosoma japonicum. METHODS: Mice infected with schistosome cercariae for 4-5 wk were treated ig with Art 100 or 300 mg.kg-1 and killed 24 h or 48 h after medication for collection of schistosomes. The activities of HK, GPI and PFK of the worms were determined by measuring the formation of NADPH or consumption of NADH. RESULTS: Worms from the infected mice treated ig with Art at a single dose of 300 mg.kg-1 the inhibition rates of HK activity of female and male worms were 33.7% and 13.7%, respectively 24 h after administration. Similar results were seen in GPI activity, but 48 h after medication, the inhibition rate of GPI increased to 46.2% (female) and 32.9% (male), respectively. Worms from mice treated with Art 100 or 300 mg.kg-1, the inhibitory effect on PFK in female worms was found much higher than that of male worms the inhibition rates of PFK were 64.9%-71.0% in female worms and 16.3%-54.2% in male worms, respectively at 24 h and 48 h after treatment. CONCLUSION: The results suggest that in the glycolytic pathway of schistosome PFK might be one of the targets attacked by Art.

Animals↗
PubMed1998

[Genotypic analysis of hepatitis C viruses and its significance in interferon treatment].

To study the genotypes of HCV infection in Shanxi Province and the response of HCV genotypes to interferon therapy, the genotypes of HCV were analysed by restriction fragment length polymorphism in 94 chronic hepatitis C patients who were positive for HCV RNA (RT-PCR). It was shown that 80 patients (85.1%) were group I infection, 12 (12.8%) were group II infection and 2 (2.1%) were group I/II co-infection. 45 chronic hepatitis C patients with different genotypes (35 with HCV group I, 10 with group II) received rIFN alpha-1b 3 MU three times a week for 6 months and were followed up to 12-34 months. The responsive rate was significantly higher in patients with group II infection (80%) than that in patients infected with group I (37.1%) (P < 0.05). Sustained response was observed in 60% for group II and in 17.1% for group I (P < 0.025). The date indicated that HCV group I is the major type of HCV infection in Shanxi Province the and HCV genotype seems to be an important factor in determining the response rate to IFN treatment in patients with chronic hepatitis C.

Adolescent↗
PubMed1998

[The experimental study on competitive PCR for quantitation of herpesviruses].

A single pair of oligonucleotide primer selected within a highly conserved region of the DNA polymerase gene in herpesviruses was synthesized. The competitive template DNA purified from cytomegalovirus (CMV) DNA was used to carry out competitive PCR amplification with herpes simplex virus type 1 (HSV1) DNA (target sequences). And anti-HSV1 effects of acyclovir (ACV) was investigated by the method. The results showed that the efficacy of PCR amplification was equal to each other(the ratio of the quantity of competitor template with DNA to the target sequence was 1.5:1). As the concentration of ACV was increased, the quantity of HSV1, DNA was decreased. It suggests that this method is practicable and some defects of mutant template can be overcomed.

Acyclovir↗
PubMed1998

[Effect of radix Achyranthis bidentatae on memory and endurance].

After P. O. decoction of Radix Achyranthis Bidentatae, continuously for seven days in mice, the drug could effectively improve the acquisition of memory of mice, significantly enhance the endurance of mice. The results indicated that the decoction of Radix Achyranthis Bidentatae has the actions of enhancing memory and endurance.

Achyranthes↗