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Biomedical subjects

G Chen

Publications and source records attributed to G Chen.

At least 199 records · Page 11Linked to original sources
PubMed2001

[Morphological changes and quantitative DNA analysis of Schwann cells in peripheral nerves after high voltage electrical injury].

OBJECTIVE: To explore the characteristics and the mechanism of the injury of Schwann cells and nerve fibres of the peripheral nerves inflicted by high voltage electricity. METHODS: Rabbits injured by high voltage electricity were employed as the model. Thirty rabbits were randomly divided into control (9) and experimental (21) groups. The dynamic quantitative DNA analysis and the change of the morphology and structure of the sciatic nerve were observed with LM and EM on 0, 3, 7, 10, 14 and 21 postburn days (PBDs), respectively. RESULTS: There was continuous degeneration of the axon and medullary sheath of sciatic nerve tissue and its neogenesis was inhibited. The DNA synthesis in Schwann cell initiated on 3 postburn day (PBD). The distribution of the current was heterogeneous on the cross section of peripheral nerve fibres. CONCLUSION: The obvious features of peripheral nerve injured by high voltage electricity included delayed initiation of the DNA synthesis of Schwann cell and the secondary necrosis and inhibition of neogenesis process of Schwann cell.

Animals↗
PubMed2001

Arsenic trioxide induces multiple myeloma cell apoptosis via disruption of mitochondrial transmembrane potentials and activation of caspase-3.

OBJECTIVE: To investigate the response of multiple myeloma (MM) cells to arsenic trioxide (As2O3) and their possible mechanisms. METHODS: Two MM-derived cell lines RPMI8226 and U266 cells were used as in vitro models. Cell apoptosis was assessed by morphology, flow cytometry, and DNA gel electrophoresis. Mitochondrial transmembrane potentials (delta psi m) were evaluated by measuring cellular Rhodamine 123 staining intensity. Protein expression was analyzed using Western blot. RESULTS: Zero point one to 0.5 mumol/L As2O3 inhibited cell proliferation and 2.0 mumol/L As2O3 induced cell apoptosis, while 1.0 mumol/L As2O3 inhibited proliferation with a weak degree of apoptosis induction in RPMI8226 and U266 cell lines. As2O3-induced apoptosis was accompanied by mitochondrial transmembrane potentials (delta psi m) collapse and caspase-3 activation in the presence of intact membrane. Glutathione depleter buthionine sulfoximine enhanced, while disulfide bond-reducing agent dithiothreitol partially antagonized As2O3-induced delta psi m collapse and apoptosis in MM cells. All-trans retinoic acid (ATRA) could also induce apoptosis in RPMI8226 cells, but it did not show any cooperative effects with As2O3. CONCLUSION: As2O3 exerts apoptosis-inducing and growth-inhibiting effects on MM cells, and mitochondrium is a pivotal and common target of As2O3 for apoptosis induction.

Antineoplastic Agents↗
PubMed2001

Prevention and treatment of hepatitis B relapse after liver transplantation.

OBJECTIVES: To investigate the effect of orthotopic liver transplantation (OLT) on hepatitis B(HB)-related diseases and the efficiency of prevention and treatment with lamivudine on recurrence of hepatitis B posttransplant in China. METHODS: Orthotopic liver transplantation (OLT) under veno-venous bypass was performed in 10, of whom 9 males had hepatitis B and 1 female had hepatocellular cancer (HCC) without HB pretransplant. Eight of the 9 males had fulminant hepatitis B (FHB) and they all had preoperative serious jaundice, ascites and coagulopathy. Six had encephalopathy; 1 was associated with acute renal failure, and 1 with gastrointestinal hemorrhage. Seven of the 10 patients had lamivudine to prevent reinfection with hepatitis B. RESULTS: Of the 8 patients who have survived for 2-12 months, 7 have survived for 6-12 months. Two died, one of recurrent FHB and the other from multi-organ failure (MOF). Seven preoprative HB patients of the 8 survivors have excellent liver function through 1 has positive HBsAg 6 months after OLT. One of the 8 survivors, the female with HCC pretransplant, suffered hepatitis B 6 months after OLT and her hepatic function has been gradually improving with lamivudine therapy. CONCLUSIONS: OLT is an effective therapy for certain cases of FHB and HCC and lamivudine may prevent recurrence of hepatitis B after OLT.

Adult↗
PubMed2001

Epstein-Barr virus infection of sinonasal lymphoepithelial carcinoma in Guangzhou.

OBJECTIVES: To investigate the prevalence of sinonasal lymphoepithelial carcinoma (SNLEC) in Guangzhou, a high incidence area of nasopharyngeal carcinoma (NPC), and to detect whether it is associated with Epstein-Barr virus (EBV) infection. METHODS: Twenty confirmed SNLEC specimens were collected from all of the sinonasal carcinoma biopsies performed in the 8 years 1989-1996 at the Sun Yat-sen University of Medical Sciences. EBV encoded early RNAs were detected by use of in-situ hybridization. A variety of antigens, including the EBV nuclear antigen 1, latent membrane protein 1, BZLF1 protein, diffuse early antigen, viral capsid antigen and membrane antigen, were detected using immunohistochemistry. Additionally, 36 NPC specimens were used for comparison. RESULTS: Twenty SNLECs were identified. Seventeen SNLECs were developed in the nasal cavity, and 3 in the maxillary sinus. The mean age (46.25 y), male to female ratio (3:1), histopathology and lymphoinfiltration of the 20 SNLECs were identical with those of the 36 NPCs. Thirteen (65.0%) of the 20 SNLECs showed an expansive growth pattern, while 27 (75.0%) of the 36 NPCs showed an infiltrating or mixed growth pattern. The majority of cancer cells in all of the 20 SNLECs showed EBV encoded early RNAs. The EBV nuclear antigen 1 expression of SNLEC was less intensive than that of NPC. The expression rate of latent membrane protein 1 for SNLEC (3/20, 15%) was lower than that for NPC (19/36, 52.8%). The expression rates of BZLF1 protein (2/20, 10.0%), diffuse early antigen (19/20, 95.0%), viral capsid antigen (15/20, 75.0%), and membrane antigen (13/20, 65.0%) for SNLEC were higher than those (0/36, 0.0%; 31/36, 86.0%; 18/36, 50%; and 14/36, 38.9%) for NPC. CONCLUSIONS: SNLEC is not uncommon in Guangzhou. This tumour is also consistently associated with EBV infection like NPC. As compared to NPC, the EBV harbored in SNLECs seems to express the EBV nuclear antigen 1 weakly and has a lower expression rate of latent membrane protein 1 as well as higher expression rates of EBV lytic products.

Adult↗
PubMed2001

Immunity induced by DNA vaccine of plasmid encoding the rhoptry protein 1 gene combined with the genetic adjuvant of pcIFN-gamma against Toxoplasma gondii in mice.

OBJECTIVE: To construct the eukáryotic expression recombinant plasmid, pcIFN-gamma, as a genetic adjuvant and observe the immune responses elicited by pcDNA3-rhoptry protein 1 (pc-ROP1) combined with pcIFN-gamma against Toxoplasma gondii (T. gondii) infection in mice. METHODS: A fragment of the IFN-gamma gene was directly inserted into the pcDNA3 plasmid and identified by two restriction endonucleases digestion. pcIFN and pcROP1 DNA was injected into the left leg muscle of mice at a dosage of 100 micrograms, and a booster vaccination was given at the same dosage after two weeks. Control groups were injected with pcDNA3 blank plasmid or normal saline. At 30, 50 and 70 days after booster injection, kinetic tests were carried out: MTT assay for the proliferation response of T lymphocyte cells and the activity of NK cells, sandwich ABC-ELISA for the determination of IFN-gamma, IL-2 and IL-10; a serum enzymetic aassay for nitric oxide (NO) in sera and ELISA for the titer of IgG antibody in sera. RESULTS: The recombinant plasmid, pcIFN-gamma was constructed. The proliferation response of spleen T lymph cells, NK cell killing activity, and serum levels of IFN-gamma, IL-2 and NO in mice injected with pcROP1 and pcIFN-gamma were higher than in those injected with pcROP1 alone. There was no difference in IgG antibody levels between the two groups. CONCLUSION: The genetic adjuvant, pcIFN-gamma, could enhance the cellular immune response induced by DNA vaccine of pcROP1 in mice against Toxoplasma gondii infection.

Animals↗
PubMed2001

The role of hypertension-related gene in aortic vascular smooth muscle cells from mice and rats.

OBJECTIVE: To study the role of hypertension-related gene (HRG-1) in cardiovascular disease. METHODS: The expression of HRG-1 was analyzed with RT-PCR and Northern blotting. Vascular smooth muscle cell (VSMC) proliferation was measured with 3H-TdR incorporation and was confirmed with histological analysis. RESULTS: Northern blot analysis showed that HRG-1 mRNA was expressed not only in VSMC, but also in various rat tissues (heart, brain, lung, kidney, and liver). In addition, the expression of HRG-1 mRNA in heart, brain, kidney and liver of spontaneously hypertensive rat (SHR) was lower than that in the same tissues of Wistar-Kyotorat (WKY). Semi-quantitative RT-PCR and histological analysis showed that the expression of HRG-1 mRNA in ApoE-knockout mice and in animal models of restenosis was decreased and neointimal formation was observed in both models. ET, AII, and IL-1 stimulating VSMC proliferation reduced the expression of HRG-1 mRNA of VSMC. Atrial natriuretic factor (ANF), calcitonin gene-related peptide and adrenomedullin, inhibited VSMC proliferation and elevated the expression of HRG-1 mRNA. These effects could be blocked or attenuated by their corresponding antagonists or antibodies. CONCLUSION: HRG-1 is a gene related to VSMC proliferation. It may play an important role in several occlusive cardiovascular diseases including atherosclerosis, restenosis and hypertension.

Animals↗
PubMed2001

Construction of a recombinant plasmid harbouring the rhoptry protein 1 gene of Toxoplasma gondii and preliminary observations on DNA immunity.

OBJECTIVE: To observe the immune responses elicited in BALB/c mice by a DNA vaccine. A gene encoding rhoptry protein 1 (ROP1) from Toxoplasma gondii (T. gondii) was cloned into vector pcDNA3. METHODS: Amplifyied gene fragments coding for ROP1 from the genomic DNA of T. gondii ZS2 were inserted into cloning vector, pUC18, and sub-cloned into pcDNA3. Mice were injected at a dosage of 100 micrograms recombinant plasmid DNA by intramuscular injection and boosted after 2 weeks. pcDNA3 and normal saline were used as control. 30, 50 and 70 days after the second immunization, NK cell activity, T lymphocyte proliferation and sub-clusters and serum IgG antibody were assayed. RESULTS: The specific gene fragment coding for ROP1 was amplified and a pcROP1 recombinant was constructed. At 30 days after immunization, the spleens of the mice were obviously enlarged evidently. NKC activity and the proliferation of spleen T lymphocytes seen on MTT assay were higher in pcROP1 group than in the controls. The number of CD4+ T cells exhibited no obvious increase compared with that of the control, but CD8+ T cells were obviously increased (P < 0.05). At 90 days after vaccination, the titer of IgG antibody in the serum of vaccinated mice was positive (1:100). CONCLUSION: pcROP1 was constructed and it could elicit both cellular and humoral immune responses in immunized mice.

Animals↗
PubMed2001

Expression and function of c-kit receptor in bone marrow mononuclear cells of patients with myelodysplastic syndromes.

OBJECTIVE: To determine the expression and function of the c-kit receptor in bone marrow mononuclear cells (BMMNC) of patients with myelodysplastic syndromes (MDS). METHODS: Direct immunofluorescence assay and reverse transcriptase-polymerase chain reaction (RT-PCR) were used to detect c-kit protein and c-kit mRNA expressions in the BMMNC of 29 MDS patients and 10 normal controls. Cell culture was used to detect the function of the c-kit receptor. RESULTS: c-kit protein expression in the MDS group was significantly higher than that in the control group (8.58% +/- 5.28% vs 3.04% +/- 1.49%, P < 0.05). c-kit protein expression in the refractory anemia (RA) group was significantly lower than that in the RA with an excess of blasts (RAEB)/RAEB in transformation (RAEB-t) group (5.12% +/- 2.13% vs 10.01% +/- 5.07%, P < 0.05). The rate of c-kit protein expression was 32.43% in acute myeloblastic leukemia (AML) cases transformed from MDS (t-AML). c-kit mRNA expression in the MDS group was correlated with c-kit protein expression. Interleukin-3 (IL-3) and erythropoietin (Epo), with or without stem cell factor (SCF), upregulated c-kit protein and its mRNA expression. In the presence of IL-3 and Epo, SCF showed significant stimulating effects on the formation of CFU-GM and BFU-E in semi-solid cultures of normal BMMNC, but had no effects on those of the MDS patients. CONCLUSION: The protein and mRNA expression of the c-kit receptor in the BMMNC of MDS patients were higher than those of normal controls, and the function of this receptor in MDS BMMNC was abnormal.

Bone Marrow Cells↗
PubMed2001

[Surgical management for colon cancer complicated with acute obstruction].

OBJECTIVE: To evaluate the feasibility of tumor resection and stage-I anastomosis for colon cancer complicated with acute obstruction. METHODS: Seventeen colon cancer patients complicated with acute obstruction admitted from 1994-1998 into our hospital, together with 1,872 cases collected from 40 reports published in the same interval in China, a total of 1,889 cases were analyzed as to the results of their surgical management. RESULTS: In the whole group, there was an incidence of 3.1% anastomotic leak, 6.6% wound infection and 1.1% pulmonary infection. Ninety-three patients died of operation with an operation mortality of 4.9%. Postoperative 5-year survival rate was 26.0%-48.0% in patients with stage-I operation. It was 20.0%-38.0% in staged operation. CONCLUSION: Tumor resection with stage-I anastomosis for colon cancer complicated with acute obstruction is acceptable giving relatively satisfactory results. Technique, bowel cleansing during the operation, rational use of antibiotics and adherence to proper indications are crucial for stage-I operation.

Acute Disease↗
PubMed2001

[Effects of activin and follistatin on FSH receptor mRNA expression of cultured Shao duck granulosa cells].

The aim of this study was to investigate the action of activin and follistatin either alone or in combination on FSH receptor mRNA expression. The results showed that activin alone increased FSH receptor mRNA level in the presence or absence of FSH in cultured granulosa cells, and the stimulating effect of activin on FSH receptor level was dose-dependent. This effect of activin was inhibited by FSP treatment which alone had no effect on FSH receptor expression. From the results, it can be concluded that activin and follistatin both exert autocrine actions on granulosa cells, and the two factors, possibly by regulating FSH receptor expression, may play important roles in follicular development.

Activins↗
PubMed2001

[Detection of neuroendocrine differentiation in NSCLC and its clinical significance].

OBJECTIVE: To study differentiation of neuroendocrine (NE) in non-small cell lung carcinoma (NSCLC) and its effect on the responsiveness to chemotherapy. METHODS: Neuron-specific enolase (NSE), chromogranin A (CgA) and synaptophysin (SYN) were detected in 42 cases of NSCLC by using Western blot and immunohistochemistry. Electron microscopy was also used to observe the ultrastructure of NE granule in above specimens. The relationship between the chemotherapeutic responsiveness and the differentiation of NE in carcinoma tissues was evaluated. RESULTS: (1) The positive rate of NE detected by Western blot is higher than that detected by immunohistochemistry and electron microscopy. (2) There is no relationship between the expression of NE and the type of lung carcinoma as well as the differentiated degree of carcinoma. (3) The positive rate of three markers detected by immunohistochemistry and Western blot methods in the group of responsive to chemotherapy is higher than that in non-responsive group (P < 0.05). CONCLUSIONS: There is a high rate of NE differentiation in NSCLC, of which NSE's rate is highest, SYN takes second place, and CgA's rate is lowest. Immunohistochemistry and Western blot method are both very useful for the diagnosis of NE differentiation in NSCLC. The sensitivity of Western blot is higher than immunohistochemistry. The differentiation of NE may be one of the factors effected the chemotherapy in NSCLC.

Aged↗
PubMed2001

Early monitoring of P(ti)O(2), P(ti)CO(2), pH and brain temperature in patients with brain injuries and the clinical significance.

OBJECTIVE: To explore the regulation of early brain tissue metabolic changing after brain injuries and the clinical significance. METHODS: There were 17 patients with brain injuries. Early dire ct monitoring of P(ti)O(2), P(ti)CO(2), pH and brain temperature, dynamic observation of the relation between various parameters and clinics after brain injuries were performed. RESULTS: Early changes of P(ti)O(2), P(ti)CO(2) and pH were closely correlated with outcome. The death rate obviously increased when P(ti)O(2) was continuously lower than 9 mmHg within 24 hours after injuries. Secondary brain injury prolonged and aggravated brain tissue metabolic disturbance. When intracerebral pressure was over 30 mmHg P(ti)O(2) began to decrease. The brain temperature in brain death patients was evidently lower than axillary temperature. CONCLUSIONS: The direct monitoring of P(ti)O(2), P(ti)CO(2), pH and brain temperature is safe and accurate and can find early anoxia da mage to brain tissue and provide reliable basis for clinical therapy. It ha s an instructive significance in selecting and studying a new treatment method in brain injuries. And it can be taken as a criterion in clinical judging brain deaths.

Adult↗
PubMed2001

[Relationship between epidemiology of HIV-1 infection and HIV-1 subtypes in Fujian province].

OBJECTIVE: To explore the relationship of AIDS epidemic and HIV-1 subtype in Fujian province of China based on molecular findings. METHODS: HIV-1 infected persons and patient with AIDS (HIV/AIDS) were identified by AIDS surveillance project in the province. AIDS epidemic situation was estimated by related data collected from the HIV/AIDS cases. HIV-1 C2-V3 region amplified from the PBMC DNA of HIV/AIDS cases was analysed by nucleotide sequencing to identified HIV-1 subtype. RESULTS: One hundred and eighty-eight cases of HIV/AIDS were found from 1987 to the end of 2000. Among 59 AIDS cases, 53 had died. HIV infection through heterosexual contacts took up 65.4%, including 44.1% of them infected abroad. Out of them, 83.1% were infected in Southeast Asia. Thirty-nine point nine percentage of the total HIV(+) were infected in China, while 9.0% were infected through blood transmission. Sequence analysis from 41 specimens showed that there were 4 kinds of HIV-1 subtypes, including A, B, C and E. Subtype E took up 75.6% (31/41), all infected by heterosexual contacts; subtype B taking up 17.1% (7/41) with most of them infected through blood transmission; subtype A and C were seen only 1 and 2 cases respectively. Gene divergence of innergroup of subtypes E was 12.245% +/- 3.894%, while subtype B was 10.762% +/- 2.707%. The high divergence of subtype E could be attributed to the region and time of infection. CONCLUSION: HIV prevalent rate has been increasing in Fujian with major transmission route of heterosexual contact. The dominant strain of HIV-1 was subtype E.

Acquired Immunodeficiency Syndrome↗
PubMed2001

[An experimental study of the sciatic nerve injury by high voltage electricity in rabbits].

OBJECTIVE: To explore the pathological and myoelectric-physiological changes and the mechanism of the early postburn sciatic nerve injury by high voltage electricity in rabbits. METHODS: Apparatus producing high electricity was established with a special-designed microrecorder of digital reserve. The electrical current values were determined by computer responsive analysis system with the concomitant determination of myoelectric-physiology and pathomorphology. RESULTS: When the current was set to be 50 HZ, the average indentical resistance value of the nerve tissue was (5.99 +/- 0.88) k omega and the average current value was 83.5 mA/cm2. There exhibited different degrees of sciatic nerve injury when examined by myoelectric-physiological and pathophysiological measures. CONCLUSION: Peripheral nerve could be injured by current of high voltage electricity.

Animals↗
PubMed2001

[Clinicopathological significance of grading on thymic epithelial tumors].

OBJECTIVE: To study the clinicopathologic relevance of a thymic epithelial tumor (TET) grading standard with the WHO classification. METHODS: A grading system for TET was proposed based on the application of WHO histological typing of thymic tumors and analyzed in relation to clinical therapy results and follow-up data of 200 TET cases. RESULTS: In this series, 8 patients (4.0%) belonged to type A, 68 (34.0%) were type AB, 17 (8.5%) were type B1, 39 (19.5%) were type B2, 27 (13.5%) were type B3 and 36 (18.0%) were type C. The remaining 5 cases were rare thymomas. The overall postoperative survival data showed highly significant differences among the histological subtypes (P < 0.001). Type A & type AB thymomas showed excellent prognosis, none of these patients died of tumor; in type B1, only 1 case (5.9%) died at 22 months postoperatively. Types B2, B3 and C thymomas shared the bad, worse and worst prognosis. Ninety-six patients (48.0%) were in stage I, 26 (13.0%) in stage II, 65 (32.5%) in stage III and 13 (6.5%) in stage IV. Clinical stage is also highly significant in predicting survival (P < 0.001). It was found that tumor histology could predict survival expectancies well in stage I and stage II cases. It was also found that type B2, B3 and C thymomas had a statistically significant worse prognosis than type A, AB and B1 thymomas (P < 0.001). According to the histology, clinical data, biological behavior and prognosis, it is proposed that thymomas be divided into 4 grades: grade I, II, III and IV. Follow-up is the best strategy for grade I & II patients after radical surgery. In this series, the 30 patients (15.0%) presenting clinical signs of myasthenia gravis were mostly in type B2 and B3 groups (P < 0.01). CONCLUSIONS: The WHO classification for TET provides good pathological definitions and criteria for diagnosis, which can independently predict the invasiveness and prognosis of TET. TET grading is of use in unifying pathological and clinical findings, in selection of proper therapy and in predicting prognosis.

Adolescent↗
PubMed2001

[Clinical observation of the protective effect of oral feeding of glutamine granules on intestinal mucous membrane].

OBJECTIVE: To observe the protective effect of oral feeding of glutamine (Gln) granules on intestinal mucous membrane during early postburn stage. METHODS: Twenty burn patients were randomly divided into test (T) and control (G) groups with 10 patients in each group. Gln granules and placebo were administered in a dose of 10 grams three times a day for 10 days to patients in the two groups respectively. Blood levels of Gln, diamine oxidase (DAO) activity, endotoxin (LPS) and intestinal permeability were monitored before and after the administration of the agents. at the same time, the changes in blood and urine routine and hepatic and renal functional indices were also observed. RESULTS: There was no difference of the general data and the hepatic and renal functional indices between the two groups. The plasma level of Gln before the administration was much lower than that thereafter (P < 0.01) in T group, but all of the values were higher than that in C group (P < 0.05). The DAO activity, intestinal permeability and LPS levels before the administration were much higher than those after it (P < 0.01) in T group. CONCLUSION: Gln might be good to burn patients due to its protective effect on intestinal mucous membrane when given during early postburn stage.

Administration, Oral↗
PubMed2001

[Sequential intensified immunosuppressive therapy combining with hematopoietic growth factors in the treatment of severe aplastic anemia].

OBJECTIVE: To explore more effective regimen for reducing early mortality of severe aplastic anemia (SAA) and improving therapeutic effectiveness. METHODS: Antilymphocyte globulin/antithymocyte globulin (ALG/ATG) and cyclosporine A (CsA) (sequential intensified immunosuppressive therapy, SIIST), with or without hematopoietic growth factors (HGFs) were administered to 73 SAA patients in a prospective randomized clinical trial to test the effectiveness of the addition of HGFs for the patients. RESULTS: The response rate of SIIST with HGFs group was significantly higher than that of SIIST alone group (89.2% vs 63.9%), with lower rates of early infection (24.3% vs 55.3%) and mortality (4.0% vs 16.7%), shorter duration of cytopenia and blood transfusion dependence and faster recovery of bone marrow hematopoiesis. The addition of HGFs to SIIST was tolerated well in all patients. There was no difference in the treatment outcome of the two groups with GM-CSF plus Epo or G-CSF plus Epo. CONCLUSION: The use of HGFs in combination with SIIST could reduce early infection and mortality rates and, therefore, improve the response rates in SAA patients.

Adolescent↗