Biomedical subjects

Q Chen

Publications and source records attributed to Q Chen.

At least 271 records · Page 15Linked to original sources

PubMed2000

Expression of fibronectin receptor, integrin alpha 5 beta 1 of hepatic stellate cells in rat liver fibrosis.

OBJECTIVE: To investigate the role of fibronectin (FN) receptor alpha 5 beta 1 in liver fibrosis. METHODS: Northern blot analysis and immunohistochemical techniques were used to observe changes in the expression of FN and FN receptor alpha 5 beta 1 on hepatic stellate cells (HSCs) in vivo and in vitro of rat liver fibrosis induced by CCl4. RESULTS: (1) alpha 5 beta 1 was mainly detected in the endothelia and some of the desmin(DM) positive cells of the sinusoids in normal rat liver. The expression of alpha 5 beta 1 of DM positive cells detected by immunohistochemistry reached its peak at the 10th week of the experiment. The changes in FN expression were similar to that of alpha 5 beta 1. (2) The expression of FN, alpha 5 and beta 1 mRNAs in the experimental group was remarkably increased especially at the 6th week, compared to that of normal liver specimens. The expression of the three mRNAs of HSCs in vitro isolated from the experimental group (6 weeks) was higher than those from normal liver. (3) The expression of FN, alpha 5 and beta 1 mRNAs increased in normal rat HSCs after treatment with transforming growth factor-beta 1 (TGF-beta 1) for 2 hours. After 4 hours of treatment, the expression of the three mRNAs fell to levels similar to the control group. Immunocytochemistry revealed that the expression of alpha 5 beta 1 of HSCs reached its peak after 4 hours of treatment with TGF-beta 1 and dropped to normal 2 hours later. CONCLUSION: These data suggest that HSCs normally express FN receptor alpha 5 beta 1. The activation of HSCs during liver fibrogenesis leads to an increase of FN, alpha 5 and beta 1 mRNA expression. The expression of FN and alpha 5 beta 1 of HSCs in vitro is up-regulated by TFG-alpha 5 beta 1. The detection of gene transcription of FN and its receptor by Northern blot analysis suggests the activation and proliferation of HSCs and thereby provides a sensitive signal of liver fibrosis.

Animals↗

PubMed2000

Effects of resveratrol on oxidative modification of human low density lipoprotein.

OBJECTIVE: To determine the antioxidative effects of resveratrol (RES), a polyphenolic compound in red wine, on the oxidation of human low density lipoprotein (LDL) using two different oxidation systems. METHODS: Oxidation of LDL was induced by adding either Cu2+ or an azo compound. The extent of LDL modification was assessed by measuring the formation of thiobarbituric acid reactive substances (TBARS), the relative electrophoretic mobilities (REM), and the amount of oxidized LDL degradation by macrophages. RESULTS: During Cu(2+)-induced oxidation, RES reduced TBARS formation in LDL by 70.5%, REM of LDL by 42.3% and the amount of macrophage degradation by 65.7%, respectively. The lag phase of LDL oxidation was also delayed by adding RES both in the copper ion and azo compound-induced oxidation systems. CONCLUSION: RES can protect LDL against both Cu(2+)-induced and azo compound-initiated oxidative modification in vitro, which might be due to its free radical scavenging capacity.

Animals↗

PubMed2000

Anisodamine protects against neuronal death following cerebral ischemia in gerbils.

OBJECTIVE: To study the effect of anisodamine on neuronal death and hydroxyl radical (OH.) production during forebrain ischemia-reperfusion in gerbils. METHODS: The tested gerbils were divided into 3 groups, including sham-operated, control and anisodamine groups. In each group, there were 8 animals for biochemical examination and 6 animals for histologic study. Forebrain ischemia was induced by occlusion the bilateral common carotid arteries for 10 min in gerbils. 2, 3- and 2, 5-DHBA outputs were determined by high performance liquid chromatography coupled with electrochemical detection. Behavioral change was tested by open field test and neuronal death was assessed by histological examination. RESULTS: The exploratory activities of gerbils in the control group were significantly higher than those in the anisodamine group on all test days. The amount of viable-looking neurons in the medial, middle and lateral CA1 sectors in anisodamine group were 41% +/- 12%, 50% +/- 21% and 67% +/- 15% of the sham-operated gerbils, respectively, being significantly higher than those in the control group (3% +/- 2%, 4% +/- 3% and 7% +/- 4% of sham, P < 0.01). The 2, 3-DHBA outputs in the control group increased by 5 fold of the sham-operated gerbils after reperfusion for 60 min, but the 2, 3-DHBA outputs in the anisodamine group were only 2.4 fold of sham-operated gerbils, being significantly lower than that in the control group (P < 0.01). The 2, 5-DHBA outputs in the control group were significantly higher than those in the sham-operated group (P < 0.05). CONCLUSION: Anisodamine has inhibitory effects on neuronal death and OH.production during cerebral ischemia-reperfusion in gerbils.

Animals↗

PubMed2000

Molecular basis of behavioral recovery following spinal cord decompression: an immunocytochemical study.

OBJECTIVES: To examine whether the expression of choline acetyltransferase (ChAT), a marker for cholinergic neurons, and growth-associated protein (GAP-43), a marker for synaptogenesis, occurs differently following compression vs. decompression of spinal cord, and whether the reactions have any relationship with the time course of behavioral recovery. METHODS: A spinal cord compression model was studied quantitatively with an immunohistochemical method. The behavioral recovery of the rat was assessed by combined behavior score (CBS). RESULTS: The rebound in the ChAT-positive cell ratio was higher in decompressed cord than in compressed one. The time course of the change in the ChAT-positive cell ratio coincided with the recovery of CBS in the two models. Increased GAP-43 expression was found in the region of injured cord in the two models. Increased GAP-43 expression was partially parallel to the recovery of CBS, both in the decompression and continuous compression groups. CONCLUSIONS: The results indicate that there are ChAT reversible neurons in both the compressed and decompressed cord, the number of which is closely related to the recovery of behavior following cord injury. Synaptogenesis plays a limited role in behavior recovery.

Animals↗

PubMed2000

[Changes of pulmonary diffusing capacity in subjects with acute mountain sickness].

OBJECTIVE: The study was conducted to investigate whether the changes in the pulmonary diffusing capacity found in individuals with acute mountain sickness (AMS) reflect the early stage of high-altitude pulmonary edema (HAPE). METHODS: According to international definition of AMS (Lake Louise Consensus) thirty-two subjects were divided into AMS and non-AMS group. The pulmonary diffusion capacity for carbon monoxide (DLco) by the single-breath method, arterialized capillary blood gas were measured in all subjects at an altitude of 2,260 m and after ascent to 4,700 m. RESULTS: All subjects exhibited an increase in DLco from 2,260 m to 4,700 m, the degree of increase in DLco in the AMS group was significantly lower than that of the non-AMS group, delta DLco (1.3 +/- 1.7) ml.min-1.mm Hg-1 vs (10.7 +/- 1.3) ml.min-1.mm Hg-1 (P > 0.01). The AMS group showed a greater alveolar-arterial oxygen pressure difference at 4,700 m compared with the non-AMS group. DLco showed a significantly negative correlation with AMS score (r = -0.885 P < 0.01). CONCLUSIONS: These results suggest that the decreased pulmonary diffusing capacity has an important role in the incidence of acute mountain sickness, it reflects the presence of pulmonary gas exchange abnormality, which is probably due to subclinical interstitial edema of the lung.

Acute Disease↗

PubMed2000

[Telomerase activity and cellular apoptosis of bladder cancers].

OBJECTIVE: To explore the relationship between clinicobiological acting, telomerase activity and cellular apoptosis of bladder cancer. METHODS: The intensity of telomerase activity and cellular apoptosis of bladder cancer were detected by telomeric repeat amplification protocol (TRAP) and terminal deoxynucleotidyl-transferase mediated dUTP-biotin nick end labeling (TUNEL) assay respectively. RESULTS: The positive rate of telomerase activity of bladder cancer was 89.29% and the apoptosis index of bladder cancer was (45.16 +/- 14.43)%. The intensity of telomerase activity and apoptosis index of bladder cancer were not related to patient's age, sex, size or number of tumor (P > 0.05), but to the "grade", "stage" and prognosis of bladder cancer (P < 0.01). The higher the intensity of telomerase activity or less cellular apoptosis, the poor prognosis of differentiated or more advanced bladder cancer. The intensity of telomerase activity was negatively correlated with cellular apoptosis of bladder cancer (r = -0.69, P < 0.01). CONCLUSIONS: The intensity of telomerase activity and cellular apoptosis are correlated with the grade, stage and prognosis of bladder cancer. The detection of telomerase activity and cellular apoptosis are helpful in clinical analysis and evaluation of prognosis of bladder cancer.

Adult↗

PubMed2000

[An epidemiological study on acute diarrhea during a filed exercise in PLA unit in an area in southern China].

OBJECTIVE: To explore the epidemiological characteristics and risk factors of acute diarrheal disease during a filed exercise. METHODS: Epidemiological study of a certain artillery acute diarrheal disease during a filed exercise and multiple linear stepwise regression analysis, multiple stepwise discriminate analysis were used. RESULTS: Result showed that the incidence rate of training troops was significantly higher than that of the local troops at the corresponding period (7.32% vs 0.98% P<0.05). The incidence rate among officers was significantly lower than that of the soldiers (0.99% vs 8.20% P<0.05). The incidence rate was significantly higher at the beginning of assemble for training but smooth and steady afterwards with several outbreaks. There was highly significant difference in the incidence rate of 39 companies. Regression and discrimination analysis suggested that the incidence rate was correlated with the density of flies and average boiled water volume provided everyday. The correct classifying rate of the discrimination was 91.9% in total. CONCLUSION: These results provided a basis for prevention of acute diarrheal disease during filed exercise of military action.

Acute Disease↗

PubMed2000

[Efficacy and immune memory of plasma-derived hepatitis B vaccine 11 years after primary immunization].

OBJECTIVE: To evaluate the long-term efficacy of hepatitis B vaccine 10 years after primary immunization to provide scientific basis for the time of revaccination. METHODS: The study was strictly designed with randomization, double-blinding, and placebo-controlled method to observe the efficacy and immune memory 11 years following hepatitis B vaccination. RESULTS: Immunogenicity and protective rate of vaccine were still kept well 11 years after immunization with a protective rate against HBV infection of 73.5%. But, there was no significant difference in HBV infection rates between vaccine group and placebo-controlled group (7.89% vs. 13.25%, P > 0.1) nine to 11 years following immunization. There still existed immune memory 11 years after immunization, but it was significantly weaker than that within the first 10 years after immunization. CONCLUSION: The efficacy of the vaccine had begun to drop 11 years after immunization, which should be followed up further to reach a clear conclusion.

Double-Blind Method↗

PubMed2000

[Effect of carbon disulfide on pyrogallol- luminol auto-oxidation chemiluminescence system and superoxide anion].

OBJECTIVE: To study the effect of carbon disulfide (CS(2)) on pyrogallol-luminol auto-oxidation chemiluminescence (PA-L) system and production of superoxide anion. METHODS: Luminescence dynamic curve of CS(2) and inhibition effect of superoxide dismutase (SOD) on intensity of chemiluminescence induced by CS(2) were studied with PA-L chemiluminescence system. RESULTS: Different concentrations of CS(2) (10, 40, 80 mg/ml) could enhance the emission intensity of chemiluminescence of PA-L system and delayed its peak time, with a significant dose-effect relationship, as compared with that of solvent ethanol. Peak of chemiluminescence induced by 80 mg/ml of CS(2) was higher than its background value without solvent ethanol. Chemiluminescence induced by CS(2) could be inhibited by SOD. CONCLUSION: CS(2) can generate superoxide anion in PA-L system and delay the peak time of chemiluminescence emission dynamic curve.

Anions↗

PubMed2000

[Comparative study of three common G6PD gene mutations in Yao and Han People in Guangxi].

OBJECTIVE: To study G6PD gene mutation diversity in Yao and Han people in Guangxi and compare the genotypic frequencies. METHODS: The three common G6PD gene mutations in Chinese were investigated in 34 G6PD deficient individuals from Yao and 37 from Han people by using an amplification refractory mutation system (ARMS). RESULTS: Among 34 cases of G6PD deficiency of Yao people, the genotypic frequencies of G1376T, G1388A and A95G were 41.2%, 26.5% and 14.7%, respectively. A case of C1311T was detected. As compared with that in Han people, the respective frequencies were 16.2%, 40.6% and 5.4%. CONCLUSION: The main G6PD mutations in Yao people were the same with Han people in Guangxi, but G1376T mutation was higher than that in Han people. The C1311T mutation in Yao people in Guangxi was reported for the first time.

Adolescent↗

PubMed2000

[Bax protein expression in the carcinogenesis of human oral mucosa].

OBJECTIVE: Bax gene is an important apoptosis-promoting gene. In order to investigate the expression of Bax in oral premalignant lesions and oral squamous cell carcinomas, a total of 38 samples are evaluated using a labelled streptavidin-biotin (LSAB) immunohistochemical assay. METHODS: A total of 38 specimens were studied, including normal oral mucosa, premalignant lesions and squamous cell carcinomas. The specimens were obtained and blocked, fixed with 10% buffered formalin and embedded in paraffin using conventional histopathological techniques. 3 microns-thick sections of paraffin-embedded tissues were cut, mounted onto slides coated with 5% APES (3-aminopropyltriethoxysilane), dried overnight at 56 degrees C, dewaxed in xylene and rehydrated through descending graded alchols to phosphate-buffered saline (PBS, pH 7.4). For antigen retrieval, slides were immersed in 10 mmol/L sodium citrate buffer (pH 6.0) and boiled twice for 5 min in a microwave oven (800 W). After treated for 10 min with 3% H2O2, 18% methanol in PBS, the slides were covered with 10% normal porcine serum for 10 min at 37 degrees C. Then slides were incubated with primary antibody (bax rabbit polyclonal antibody) for 60 min at 37 degrees C and were subsequently incubated with prediluted biotinylated antibody against rabbit immunogobulins, and streptavidinhorseardish peroxidase conjugate for 30 min at 37 degrees C. After washing, peroxidase activity was detected using 3,3'-diaminobenzidine as chromogen with H2O2 as substrate. The cells in the test specimens which demonstrated granular staining were considered as positive. A haemocytometer counter with 6. 6 framework were applied and only the positive cells on the cross were counted. The cell counting were processed in ten randomly chosen 400* microscopic fields and the mathematic mean was presented as the final counting of each sample. Statistical valuations were performed using the version 6.0 SPSS package. Positive controls were sections of bladder cancer tissues. Blank controls were fabricated for each specimen by the omission of the primary antibody, which was replaced with PBS. RESULTS: In the process of oral carcinogenesis, each stage had Bax expression. The positive staining appeared in cytoplasm. In the normal oral mucosal specimens Bax expression was evident in the prickle layer, but not in the basal cell layers. Various degrees of Bax expression were seen in the diseased tissues. The staining pattern of hyperkeratotic lesions was similar to the normal oral mucosa, but Bax expression were also seen in the basal cell layer. In the mild, moderate, severe dysplasia and squamous cell carcinomas, Bax expression were seen in all layers, however, the intensity of staining were greater in mild and moderate dysplasia. The number of positive cells tended to increase gradually with the development of cell malignancy in the tissues of hyperkeratosis, mild and moderate dysplasia (P < 0.05). In the tissue of squamous cell carcinomas the number of positive cells had no marked difference comparing with the normal oral mucosa. CONCLUSION: The expression of Bax is involved in oral carcinogenesis and the compensative increase of Bax protein expression may be an early response.

Apoptosis↗

PubMed2000

[Bacillus subtilis undergoes natural genetic transformation on agar plates].

This paper conducted preliminary investigation on natural genetic transformation of Bacillus subtilis on agar plates. The results showed that, under same conditions, the natural transformation of the strain on agar plate was much more efficient than that of standard liquid method, and the transformation system could sustain higher DNase concentration. In addition, that the LB culture, which usually did not support the strain acquire competency, could undergo transformation as soon as it being spread on agar plate, suggested that the natural genetic transformation of Bacillus subtilis on solid plates may be different form the standard liquid transformation method. The cell-to-cell transformation between strains having different genetic makers could also be observed on agar plates.

Agar↗

PubMed2000

[Preparation of monoclonal antibodies against malaria through immunization of mice with recombinant plasmid DNA].

BALB/c mice were immunized by injection of recombinant plasmid DNA carrying MSP1-31 fragment of Plasmodium falciparum. After antiserum was induced, McAbs were prepared by fusing SP2/0 myeloma cells with spleen cells. Specific McAbs were detected in hybridoma culture supernatant and mouse ascites by ELISA, positive hybridomas were cloned by technique of limiting dilutions. Two McAbs, 9H9 and 8A2, against the malaria protein were produced and characterized. The titers of the two McAbs in acites were 1:10,000 and 1:2500 respectively. The Ig subclass of these McAbs was IgG1. Western blot test showed that the McAb specifically reacted with MSP1-31 antigen. These results proved that monoclonal antibodies could be produced by use of immunization of mice with plasmid DNA or DNA vaccine.

Animals↗

PubMed2000

[Isolation and identification of myxobacteria].

This paper reported that the authors isolated large numbers of myxobacteria from more than 100 samples collected in many places of China. More than 400 pure strains were obtained. These strains belonged to 10 genera of Myxococcales. The most frequent genera isolated were Myxococcus, Sorangium, Corallococcus, and Cystobacter. Melittangium was seldom isolated. No Chondromyces and Haploangium were found.

Cellulose↗

PubMed2000

[Intrathecal synthesis of the anti-Hu antibody in patients with paraneoplastic encephalomyelitis or sensory neuronopathy].

OBJECTIVE: To probe into the pathogenic mechanisms of paraneoplastic encephalomyelitis (PEM) or sensory neuronopathy(PSN). METHODS: The serum and cerebral spinal fluid(CSF) anti-Hu antibodies and titers in 16 patients with PEM and 14 patients with PSN were detected with indirect immunohistochemistry (ABC) method. Intrathecal IgG synthesis and antibody specific activity (ASA) were calculated with Schuller's formulas according to the titers of the anti-Hu antibodies in the serum and CSF of the patients. Anti-Hu antibodies were identified by detecting the antigens of the nuclear extracts from the human cerebral cortex neurons with Western blot analysis. IgG in the serum and CSF and the albumin in the CSF were tested with electroimmunodiffusion method. RESULTS: The serum and CSF anti-Hu antibody titers in patients with PEM were significantly higher than those in patients with PSN (P < 0.001). A ratio of intrathecal ASA/serum ASA of anti-Hu antibody > 2 in 14 (88%) of the 16 patients with PEM and one (7%) patient with PSN indicated that the patients with PEM had a positive intrathecal anti-Hu antibody synthesis (P < 0.001). The Rankin scores are 4.5 +/- 1.7 in patients with PEM and 3.0 +/- 1.4 in patients with PSN (P < 0.01). Patients with PEM were more disabled than those with PSN. CONCLUSIONS: The detection of intrathecal ASA/serum ASA ratio for identifying the anti-Hu antibody intrathecal synthesis is valuable in judging the severity of disease and prognosis in patients with paraneoplastic syndromes of nervous system.

Adult↗

PubMed1999

Small, clonally variant antigens expressed on the surface of the Plasmodium falciparum-infected erythrocyte are encoded by the rif gene family and are the target of human immune responses.

Disease severity in Plasmodium falciparum infections is a direct consequence of the parasite's efficient evasion of the defense mechanisms of the human host. To date, one parasite-derived molecule, the antigenically variant adhesin P. falciparum erythrocyte membrane protein 1 (PfEMP1), is known to be transported to the infected erythrocyte (pRBC) surface, where it mediates binding to different host receptors. Here we report that multiple additional proteins are expressed by the parasite at the pRBC surface, including a large cluster of clonally variant antigens of 30-45 kD. We have found these antigens to be identical to the rifins, predicted polypeptides encoded by the rif multigene family. These parasite products, formerly called rosettins after their identification in rosetting parasites, are prominently expressed by fresh isolates of P. falciparum. Rifins are immunogenic in natural infections and strain-specifically recognized by human immune sera in immunoprecipitation of surface-labeled pRBC extracts. Furthermore, human immune sera agglutinate pRBCs digested with trypsin at conditions such that radioiodinated PfEMP1 polypeptides are not detected but rifins are detected, suggesting the presence of epitopes in rifins targeted by agglutinating antibodies. When analyzed by two-dimensional electrophoresis, the rifins resolved into several isoforms in the pI range of 5.5-6.5, indicating molecular microheterogeneity, an additional potential novel source of antigenic diversity in P. falciparum. Prominent polypeptides of 20, 22, 76-80, 140, and 170 kD were also detected on the surfaces of pRBCs bearing in vitro-propagated or field-isolated parasites. In this report, we describe the rifins, the second family of clonally variant antigens known to be displayed by P. falciparum on the surface of the infected erythrocyte.

Amino Acid Sequence↗

PubMed1999

Endothelin antagonists: substituted mesitylcarboxamides with high potency and selectivity for ET(A) receptors.

We have previously disclosed the discovery of 2,4-disubstituted anilinothiophenesulfonamides with potent ET(A)-selective endothelin receptor antagonism and the subsequent identification of sitaxsentan (TBC11251, 1) as a clinical development compound (Wu et al. J. Med. Chem. 1997, 40, 1682 and 1690). The orally active 1 has demonstrated efficacy in a phase II clinical trial of congestive heart failure (Givertz et al. Circulation 1998, 98, Abstr. #3044) and was active in rat models of myocardial infarction (Podesser et al. Circulation 1998, 98, Abstr. #2896) and acute hypoxia-induced pulmonary hypertension (Chen et al. FASEB J. 1996, 10 (3), A104). We now report that an additional substituent at the 6-position of the anilino ring further increases the potency of this series of compounds. It was also found that a wide range of functionalities at the 3-position of the 2,4,6-trisubstituted ring increased ET(A) selectivity by approximately 10-fold while maintaining in vitro potency, therefore rendering the compounds amenable to fine-tuning of pharmacological and toxicological profiles with enhanced selectivity. The optimal compound in this series was found to be TBC2576 (7u), which has approximately 10-fold higher ET(A) binding affinity than 1, high ET(A)/ET(B) selectivity, and a serum half-life of 7.3 h in rats, as well as in vivo activity.

Administration, Oral↗

PubMed1999

Beta-defensins: linking innate and adaptive immunity through dendritic and T cell CCR6.

Defensins contribute to host defense by disrupting the cytoplasmic membrane of microorganisms. This report shows that human beta-defensins are also chemotactic for immature dendritic cells and memory T cells. Human beta-defensin was selectively chemotactic for cells stably transfected to express human CCR6, a chemokine receptor preferentially expressed by immature dendritic cells and memory T cells. The beta-defensin-induced chemotaxis was sensitive to pertussis toxin and inhibited by antibodies to CCR6. The binding of iodinated LARC, the chemokine ligand for CCR6, to CCR6-transfected cells was competitively displaced by beta-defensin. Thus, beta-defensins may promote adaptive immune responses by recruiting dendritic and T cells to the site of microbial invasion through interaction with CCR6.

Antibodies↗