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Biomedical subjects

C Wang

Publications and source records attributed to C Wang.

At least 739 records · Page 41Linked to original sources
PubMed1997

Role of the RepA1 protein in RepFIC plasmid replication.

Using a sensitive primer extension technique, we have carried out studies to localize the start site of replication of the replicon RepFIC. In the course of these studies, we have found evidence that supports the hypothesis that transcription is an integral component of the initiation of replication. On the basis of our findings, we suggest that the transcript is processed to act as a primer, and therefore we propose that the transcript has a dual role as primer of replication and mRNA for the RepA1 protein. We present a model, based on our evidence, for the initiation of replication of the replicon RepFIC. This model provides as well an alternative explanation for what has been called the cis action of RepA1, and we show that RepA1 may act in trans as well as in cis.

Bacterial Proteins↗
PubMed1997

Characterization of a neurotoxigenic Clostridium butyricum strain isolated from the food implicated in an outbreak of food-borne type E botulism.

Neurotoxigenic Clostridium butyricum was isolated from the food implicated in an outbreak of clinically diagnosed type E botulism in China. PCR assay showed that the isolate (LCL 155) contained the type E botulinum toxin gene. This appears to be the first report of neurotoxigenic C. butyricum causing food-borne botulism.

Bacteriological Techniques↗
PubMed1997

Animal model of mucosally transmitted human immunodeficiency virus type 1 disease: intravaginal and oral deposition of simian/human immunodeficiency virus in macaques results in systemic infection, elimination of CD4+ T cells, and AIDS.

Chimeric simian/human immunodeficiency virus (SHIV) consists of the env, vpu, tat, and rev genes of human immunodeficiency virus type 1 (HIV-1) on a background of simian immunodeficiency virus (SIV). We derived a SHIV that caused CD4+ cell loss and AIDS in pig-tailed macaques (S. V. Joag, Z. Li, L. Foresman, E. B. Stephens, L. J. Zhao, I. Adany, D. M. Pinson, H. M. McClure, and O. Narayan, J. Virol. 70:3189-3197, 1996) and used a cell-free stock of this virus (SHIV(KU-1)) to inoculate macaques by the intravaginal route. Macaques developed high virus burdens and severe loss of CD4+ cells within 1 month, even when inoculated with only a single animal infectious dose of the virus by the intravaginal route. The infection was characterized by a burst of virus replication that peaked during the first week following intravenous inoculation and a week later in the intravaginally inoculated animals. Intravaginally inoculated animals died within 6 months, with CD4+ counts of <30/microl in peripheral blood, anemia, weight loss, and opportunistic infections (malaria, toxoplasmosis, cryptosporidiosis, and Pneumocystis carinii pneumonia). To evaluate the kinetics of virus spread, we inoculated macaques intravaginally and euthanized them after 2, 4, 7, and 15 days postinoculation. In situ hybridization and immunocytochemistry revealed cells expressing viral RNA and protein in the vagina, uterus, and pelvic and mesenteric lymph nodes in the macaque euthanized on day 2. By day 4, virus-infected cells had disseminated to the spleen and thymus, and by day 15, global elimination of CD4+ T cells was in full progress. Kinetics of viral replication and CD4+ loss were similar in an animal inoculated with pathogenic SHIV orally. This provides a sexual-transmission model of human AIDS that can be used to study the pathogenesis of mucosal infection and to evaluate the efficacy of vaccines and drugs directed against HIV-1.

Acquired Immunodeficiency Syndrome↗
PubMed1997

Effect of cyclosporin A on the expression of tissue kallikrein, kininogen, and bradykinin receptor in rat.

The tissue kallikrein-kinin system is involved in vasodilation and blood pressure regulation. In the present study, we investigated the effects of chronic cyclosporin A (CsA) administration on blood pressure and the expression of tissue kallikrein, kininogen, and bradykinin receptor in normotensive Wistar rats. Chronic administration of CsA significantly increased systolic blood pressure compared with control rats (n = 6, P < 0.01), although body weight was significantly lower than control rats (n = 6, P < 0.01). The development of hypertension was accompanied by the altered expression of kallikrein-kinin system components. Immunoreactive renal kallikrein and urinary excretion of tissue kallikrein levels were increased by chronic administration of CsA (n = 5 or 6, P < 0.05). Levels of N-tosyl-L-phenylalanine chloromethyl ketone-trypsin and kallikrein-releasable kininogens in sera increased in response to chronic CsA treatment (n = 5 or 6, P < 0.05). Chronic CsA treatment significantly increased renal kallikrein, bradykinin B2 receptor, and hepatic kininogen mRNA levels. The increased levels of tissue kallikrein-kinin system components were accompanied by significant increases in 24-h urine excretion and water intake after chronic CsA treatment (n = 5, P < 0.05). These results suggest that enhanced activity of the tissue kallikrein-kinin system may compensate for the CsA-induced vasoconstriction and hypertension.

Animals↗
PubMed1997

Photovoice: concept, methodology, and use for participatory needs assessment.

Photovoice is a process by which people can identify, represent, and enhance their community through a specific photographic technique. As a practice based in the production of knowledge, photovoice has three main goals: (1) to enable people to record and reflect their community's strengths and concerns, (2) to promote critical dialogue and knowledge about important issues through large and small group discussion of photographs, and (3) to reach policymakers. Applying photovoice to public health promotion, the authors describe the methodology and analyze its value for participatory needs assessment. They discuss the development of the photovoice concept, advantages and disadvantages, key elements, participatory analysis, materials and resources, and implications for practice.

Adolescent↗
PubMed1997

Prostate-specific antigen in female serum, a potential new marker of androgen excess.

Prostate-specific antigen (PSA) is present at very low concentrations in female serum, but it can now be measured with highly sensitive immunoassays. We have found that in female tissues the PSA gene is regulated by steroid hormones through the action of steroid hormone receptors. Thus, we examined whether female serum PSA is associated with hyperandrogenic states. Serum PSA levels were compared between 22 hirsute women with a Ferriman-Gallwey score higher than 8 and 50 women without hirsutism. The results show that PSA levels were higher in hirsute women in comparison with controls. In hirsute women, levels of PSA and 3 alpha-androstanediol glucuronide (3 alpha-AG), a specific metabolite of androgen action, showed a significant positive correlation, whereas PSA and 3 alpha-AG showed a significant negative correlation with patient age. Receiver operating characteristic (ROC) analysis revealed that 3 alpha-AG was a slightly better marker of androgen excess than PSA. We conclude that female serum PSA may be a new biochemical marker of androgen action in females.

Adolescent↗
PubMed1997

Androgen replacement therapy.

Androgen therapy has been primarily used for replacement therapy in symptomatic hypogonadal men. Other indications under clinical investigation include androgen replacement therapy for older men with age-associated decline in serum testosterone levels, muscle-wasting disease, male contraception and as adjunctive therapy to oestrogen (and progesterone) hormone replacement for postmenopausal women. Recent scientific and pharmaceutical interests led to development of new long-acting injectables, transdermal delivery systems and sublingual preparations. The benefits of androgen replacement must be weighed against the potential risks when androgens are used in conditions other than male hypogonadism. In the future, designer androgens with specific beneficial effect on sexual function, mood, bone and muscle mass but with attenuated effects on serum lipid profiles and the prostate gland may be developed.

Androgens↗
PubMed1997

[Androgen receptor gene mutations in prostate cancer].

PURPOSE: Androgens are required for the development of normal prostate and prostate cancer, through their action via the androgen receptor (AR). Although prostate cancer is potentially curable in the early stages by radical prostatectomy, androgen ablation is standard treatment for metastatic prostate cancer. Metastatic prostate cancer is incurable despite temporary remission commonly achieved by androgen ablation therapy. To investigate the mechanism for the development of human prostate cancer, examination was made of AR gene mutations. MATERIALS AND METHODS: Thirty-two samples including 29 primary prostate cancers and 3 metastatic lymph nodes were examined from exons B to H of the AR gene by polymerase chain reaction of single-strand conformation polymorphism (PCR-SSCP) and direct-sequencing analysis. Three metastatic lymph nodes were removed from non-hormone treated stage D1 patients by radical prostatectomy. Six of 11 stage D2 patients were hormone-independent stage following androgen ablation therapy. RESULTS: One of 29 (3.4%) primary prostate cancers and 1 of 6 (16.7%) hormone-independent stage D2 patients showed the AR mutation. This AR mutation is a G to A transition at nucleotide 2677 that leads to substitution of glutamine (CAG) for the wild type arginine (CGG) at codon 629. The serum prostate specific antigen level of the patients increased to 480 ng/ml. Drugs for hormone therapy and duration of treatment had the same effects on the remaining 5 hormone-independent patients. No mutation was found in the other 28 primary prostate cancer or 3 metastatic lymph node samples. CONCLUSIONS: The AR mutation may possibly be involved in the development of prostate cancer from the androgen-dependent to -independent stage during androgen ablation therapy.

Aged↗
PubMed1997

[Changes of plasma endothelium-derived relaxing factor and endothelin-1 in patients with chronic cor pulmonale at exercise test].

OBJECTIVE: The authers investigated the levels of plasma EDRF-nitric oxide (NO) and ET-1 in 10 cases of cor pulmonale at exercise. METHODS: Using the technologies of cardiac catheter, radioimmunization and biochemical analysis. RESULTS: The level of plasma NO was lower in group A (mean pulmonary artery pressure (mPAP) < 2.67 kPa) than in group B (mPAP > or = 2.67 kPa) at rest; the content of plasma NO increased more markedly in group A than in group B during exercise; there was no change in the content of ET-1 in both groups; mPAP strongly correlated with plasma NO or ET-1 in both groups. CONCLUSIONS: The patients with cor pulmonale at early stage may be in a state of compensated release of NO, but its release reserve has been reduced.

Aged↗
PubMed1997

[Clinical study of bioactive glass ceramics as orbital implants].

One hundred and two patients received a bioactive glass ceramics as an orbital implant of 98 cases 96.1% were successful after operation. Of 4 cases that underwent operation, conjunctiva was torn partly when stitches were taken out of the wound. One out of four had to remove the orbital implant. After a follow-up of 6 months to 2 years, there were no complications. All patients were satisfied with their cosmetic appearance and motility although drilling of the motility hole as a secondary procedure was not peformed.

Adolescent↗
PubMed1997

[Protective effects of 15-methyl-prostaglandin F2 alpha on primary cultured rat hepatocyte against CCl4-induced injury].

The effect of 15-Mt-PGF2 alpha on CCl4-induced injury of primary cultured hepatocytes was studied. 15-Mt-PGF2 alpha treatment (2 mg/L) significantly decreased CCl4 (10 mmol/L)-induced damages of primary cultured rat heptocytes as indicated by decreases GPT and GOT leakage and LPO production. 15-Mt-PGF2 alpha significantly promoted 3H-uridine incorporation into RNA and [3H]-thymidine incorporation into DNA of the rat hepatocytes. Cytopathology study showed that 15-Mt-PGF2 alpha attenuated damages of mitochondria, endoplasmic reticulum and ribosome caused by CCl4. 15-Mt-PGF2 alpha appeared to maintain the stability of rat hepatocytes by inhibiting lipid peroxidation. These results indicated that 15-Mt-PGF2 alpha has notable protective effect on primary cultured rat hepatocytes against CCl4-induced damage by reducing lipid peroxidation and promoting synthesis of RNA and DNA.

Animals↗
PubMed1997

Clinical comparison of pulsatile and nonpulsatile perfusion during cardiopulmonary bypass.

Controversy exists concerning the utilization of pulsatile flow during cardiopulmonary bypass (CPB) with regard to improved patient outcomes. The purpose of the present study was to evaluate pulsatile perfusion in patients undergoing CPB in a clinical setting. Seventy patients undergoing open heart surgery for repair of valvular or congenital heart disease were prospectively entered into the study and were randomly assigned to either pulsatile perfusion (PP, n = 35) or nonpulsatile perfusion (NP, n = 35) groups. All patients received identical surgical, perfusion, and postoperative care. Study parameters included: rate of spontaneous cardiac conversion, inotropic drug use, urine output, skin temperature, platelet count, fibrinogen concentration, and plasma free hemoglobin level. There were no statistically significant differences seen in either preoperative or operative parameters between groups. The PP group had a significantly higher rate of spontaneous cardiac conversion, less inotropic drug use, earlier recovery of skin temperature, and higher urine output during CPB (908.8 +/- 87.2 ml/hr vs. 606.1 +/- 57.5 ml/hr, p < .01). There were no significant differences in either platelet count or fibrinogen concentration between groups. There was a steady increase in plasma free hemoglobin during PP, which was not seen in the NP group (p < .01). We conclude that the use of pulsatile flow resulted in improved patient outcomes in maintaining better renal function and preserving cardiac function in the early post-bypass period.

Adult↗
PubMed1997

[Study on relationship between proto-oncogene expression of c-fos and c-myc in airway, lung tissue and asthma in guinea pigs].

In order to investigate the mechanism of the attack of asthma, the authors examined the proto-oncogene expression of c-fos and c-myc in the airway and lung tissue of the ovalbumin-induced asthmatic guinea pigs by using Dot-blot. Northern-blot and immunohistochemical techniques. There was a baseline expression of c-fos and c-myc in the controls, whereas the mRNA expression of c-fos and c-myc increased much more significantly in asthmatic guinea pigs, it reached maximum at 30 min after the onset of asthma and it was in a time dependant manner. The inducement could be inhibited partially by dexamethasone. Immunohistochemical investigation showed that c-fos and c-myc was distributed mainly in epithelial cells of the airway. The staining was more intensive in the asthmatic guinea pigs than in the controls. The results suggest that the increase in proto-oncogene expression of c-fos and c-myc may be related to the attack of asthma.

Animals↗
PubMed1997

[Research on types of Salmonella in some animals in Jilin province].

Some animals were examined for the presence of Salmonella in Jilin province. The rate of Salmonella detection was 537 strains from 846 snakes samples (63.5%); 136 strains from 648 frog samples (20%); 185 strains from 369 pig and chick samples (50%). All isolated Salmonella comprised of two subgenus (SII and SIIIb). Serologically, groups 04, 07, 08, 09, 01, 03, 19, 03, 10, 016, 035, 043, 048, 050, 058 and 061 were identified and the isolates were classified into 13 groups and 24 serotypes. Two of these isolates SII43:enZ15:1, 6 and SIIIb58:Z52:Z are reported for the first time in China.

Animals↗
PubMed1997

[mRNA expression of granulocyte-macrophage colony-stimulating factor in airway tissues of asthma guinea pigs: effect of triptolide].

OBJECTIVE: To explore the role of granulocyte-macrophage colony-stimulating factor (GM-CSF) in eosinophil inflammation of asthma airway. METHODS: Guinea pig models of asthma were established with aerosolized ovalbumin. A group of asthmatic guinea pigs were treated with injection of triptolide, density of eosinophil infiltration in airway tissues was observed under microscope and expression of GM-CSF mRNA in airway tissues was detected with dot hybridization by Dig-labeled cDNA probe. RESULTS: Expression of GM-CSF mRNA in asthmatic animals were higher markedly than that in the triptolide-treated and the control groups. However, there was no statistically differences of density of eosinophils infiltration between the asthma and the triptolide-treated groups. CONCLUSIONS: GM-CSF might participate in eosinophil inflammation in airway of asthmatic animals and triptolide might be of potential value in anti-inflammation for asthma.

Animals↗
PubMed1997

[Studies on basis and methods for examination of ruled characters].

Although the writer of ruled characters temporarily changes his movement habits forcefully, the static impression of characters in mind still determines the characteristics of structures and wrongly written. The static impression controls ruled writing. This builds up the basis for the examination of ruled characters. The main methods for examination is to find in characters special structures, stroke collocation, and wrongly written.

Forensic Medicine↗