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Biomedical subjects

C Wang

Publications and source records attributed to C Wang.

At least 847 records · Page 47Linked to original sources
PubMed1996

Comparative adrenocholinergic control of intracellular Ca2+ in the layers of the ciliary body epithelium.

PURPOSE: Both nonpigmented epithelia (NPE) and pigmented epithelia (PE) of the ciliary body are thought to participate in the formation of aqueous humor and its pharmacologic regulation. The aim of this study was to identify the similarities and differences in intracellular Ca2+ ([Ca2+]i) changes in each of the two layers in response to adrenergic and cholinergic inputs. METHODS: Incubation of the Dutch belted rabbit ciliary body (CB) in low-[Ca2+] solution was used to induce the functional dissociation of the NPE and PE layers from each other. These layers or the intact undissociated CB were loaded with the fluorescent Ca2+ indicator fura-2 and mounted in superfusion chambers for fluorometric measurement of [Ca2+]i. RESULTS: In the NPE of the intact CB epithelium or in the isolated NPE, 10 microM acetylcholine (ACh), 1 microM brimonidine (UK 14304), or 1 microM epinephrine each elicited minimal rises in [Ca2+]i. On the other hand, the combination of either adrenergic drug with ACh resulted in large mobilizations of this cation. The alpha 1-adrenergic agonist phenylephrine was unable to induce Ca2+ mobilization in the isolated NPE and failed to do so in 10 of 12 intact CB specimens. In the isolated PE, both epinephrine and phenylephrine elicited substantial similar [Ca2+]i increases, ACh induced a smaller and slower rise, and the response to its combination with either adrenergic drug was essentially additive. UK 14304 (+/- ACh) had no measurable effect in these cells. CONCLUSIONS: Each layer of the CBE exhibits distinct alpha-adrenergic control mechanisms. The NPE contains an alpha 2-adrenergic mechanism highly dependent on the cholinergic tone. The PE, in contrast, contains an alpha 1-adrenergic pathway that operates independently of cholinergic input. This segregation of mechanisms provides a basis for highly complex regulatory responses in the intact, syncytially organized ciliary body epithelium.

Acetylcholine↗
PubMed1996

Data from men in greater Seattle area reveals no downward trend in semen quality: further evidence that deterioration of semen quality is not geographically uniform.

OBJECTIVE: To determine whether there has been a decline in semen quality in a group of healthy men during the past 21 years. DESIGN: Retrospective analysis of the relationship between time and changes in semen parameters over 21 years using regression analysis. SETTING: A tertiary university center. PATIENTS: Five hundred ten healthy, normal men who donated multiple semen samples as participants in clinical studies between 1972 and 1993. MAIN OUTCOME MEASURES: Sperm concentration, semen volume, total numbers of sperm per ejaculate, and percent spermatozoa with normal morphology. RESULTS: There was no decrease in sperm concentration, semen volume, total number of sperm per ejaculate, and percent normal sperm morphology in 510 healthy men studied between 1972 and 1993. CONCLUSION: We conclude that in this population of healthy young men there has not been any decline in semen quality in the past 21 years.

Fertility↗
PubMed1996

Hyaluronan distribution in the normal epithelium of esophagus, stomach, and colon and their cancers.

The distribution of hyaluronan (HA) in normal gastrointestinal wall and in tumors originating from their epithelium was studied using a specific probe prepared from cartilage proteoglycan (bHABC, biotinylated hyaluronan binding complex). The normal stratified squamous epithelium of esophagus showed an intense HA staining in the basal and lower intermediate layers, whereas the simple epithelia in the stomach and large intestine were HA negative. Esophageal in situ carcinomas expressed HA also in the cell layers close to the luminal surface, in regions normally negative. Most of the invasive squamous cell carcinomas maintained their HA expression, but in very poorly differentiated types the tumor parenchyma was devoid of HA. In both gastric and colonic adenocarcinomas the tumor parenchyma showed no HA. The stromal tissue was intensely HA positive in all tumors. Cancer cells invading the intestinal smooth muscle were surrounded by copious amounts of HA, whereas the muscular layer was otherwise very poor in HA staining. These results show that relatively well differentiated carcinoma cells themselves retain the high or low HA expression pattern of their original epithelium, whereas tumors stimulate HA deposition in the surrounding stroma.

Colon↗
PubMed1996

[A PCR marker-based selection for resistance to bacterial blight in rice].

Molecular marker-based selection in plant breeding requires not only suitable molecular markers closely linked to the known genes, but a simple, economic and reliable analyzing technique. We report here a useful PCR marker for genetic diagnostics in breeding for resistance to rice bacterial blight. Xa21 is a newly found gene of rice which confers resistance to bacterial blight caused by Xanthomonas oryzae pv. oryzae. We produced two F2 populations between one resistant line IRBB21 containing Xa21 and two susceptible varieties, respectively. One PCR marker, PB78, detected polymorphism between the susceptible varieties and the resistant line. Cosegregation between Xa21 and PB78 was studied in the two F2 populations. The results showed that Xa21 was closely linked to the molecular marker, the crossing over value was 2.48%. Marker-based selection revealed that 100% of the plants with homozygous resistant genotype of PB78 showed resistance to bacterial blight. The available approaches detecting molecular markers in plant breeding are also discussed.

Base Sequence↗
PubMed1996

Field studies on the preventive effect of oral artemether against schistosomal infection.

OBJECTIVE: To study the preventive effect of oral artemether (Art) against schistosomal infection in the field. METHODS: In Minglang District of Yiyang City, Hunan Province, there is an islet with embankment type endemic area in the southern Dongting Lake region. From August to October 1994 the residents who frequently contacted the infested water were selected for study and allocated to the Art group and the control group. About one month before the preventive Art administration, all the residents understudied were examined by stool hatching technique, and then treated orally with praziquantel at a single dose of 40 mg/kg in stool egg-negative residents and 50 mg/kg in stool egg-positive ones. In the Art group, the first dose of 6 mg/kg was given at the end of August, followed by 3 repeated doses every 15 days. Placebo (starch) was given to the control group at the same time as in the Art group. The preventive efficacy was evaluated by stool examination 25-32 days after the last medication. RESULTS: In the Art group, 20 out of 365 studied residents became stool positive with an infection rate of 5.5%, while in the control group, 51 out of 376 studied residents were stool positive with an infection rate of 13.6%. The egg count per gram of feces (EPG) determined by the Kato-Katz method was 122 +/- 79 in the Art group and 681 +/- 909 in the control group. Meanwhile, two cases of acute schistosomiasis were found in the control group, but none was observed in the Art group. No apparent adverse side effect was seen during the treatment with Art. CONCLUSION: Oral Art exhibited apparent preventive effect on the residents who contacted the infested water in schistosomiasis endemic area.

Administration, Oral↗
PubMed1996

The combination of melphalan, cyclophosphamide and cytosine arabinoside as a conditioning regimen for autologous bone marrow transplantation for acute leukemia.

OBJECTIVE: To explore more effective and less toxic conditioning regimen without total body irradiation for autologous bone marrow transplantation (ABMT) for acute leukemia (AL). MATERIAL AND METHODS: Twenty patients with AL were treated with ABMT, including 13 cases of acute myelocytic leukemia (AML) and 7 cases of acute lymphocytic leukemia (ALL). A median of 1.06 (range, 0.69-1.75) x 10(8) nucleated BM cells/kg was harvested and stored in normal salt solution containing heparin at 4 degrees C. The conditioning regimen (MAC) consisted of high-dose melphalan (M, 140-160 mg/m2), cyclophosphamide (CY, 120 mg/kg) and cytosine arabinoside (Ara-C, 2.0 g/m2). These 3 drugs were administered within 25 hours and the unpurged autologous marrow infusion began after another 24-hour interval. RESULTS: MAC regimen could result in myeloblastic efficacy in a week. All marrow cells were reinfused within 56 hours after the harvest so that hemopoietic reconstitutions could occur in all the patients. The median time to reach a neutrophil count of > 1.0 x 10(9)/L and a platelet count of > 50 x 10(9)/L was 20 and 26 days respectively. With a median observation period of 25 months, the median duration on continuous complete remission in our patients was 22 months, and the longest reached 56 months. The median survival was 33 months, and the longest was over 6 years. The event-free survival at 2 years had reached 72%. In seven patients with leukemic relapse, six (86%) relapsed within 8 months after ABMT. The relapse rate and mortality in AML patients were significantly lower than those in ALL patients. In 7 patients with M3, relapse had not yet been observed. The nonhematologic toxic effects of MAC conditioning regimen occurred mainly in the gastrointestinal tract. CONCLUSIONS: The preliminary results indicated that the ABMT using MAC conditioning regimen had some advantages in stronger antileukemic efficacy, less extrahematologic toxicity and earlier recovery of platelet and could greatly prolong the duration of remission and survival in some patients with AL.

Adolescent↗
PubMed1996

Interaction between fulvic acids of different origins and active oxygen radicals.

Using the spin trapping technique, the interaction between fulvic acids (FAs) of different origins and the active oxygen radicals was studied. The active oxygen radicals under study included superoxide anion (O2.-) produced by xanthine oxidase (XOD) and stimulated polymorphonuclear leukocytes (PMN) of human being and hydroxyl radical (.OH) produced from Fenton's reaction. It has been found that the FAs from both Kaschin-Beck disease (KBD) region and non-KBD region can accelerate the production of .OH and scavenge O2.-. FA from peat can scavenge both O2.- and .OH. The results show that the behavior of KBD and non-KBD FAs differs clearly from peat FA. It has been concluded that the superoxidation damage of KBD induced by FA is mainly due to hydroxyl radical reaction initiated in biological system.

Benzopyrans↗
PubMed1996

Human renal cancers resistant to IFN's antiproliferative action exhibit sensitivity to IFN's gene-inducing and antiviral actions.

PURPOSE: Although treatment with interferon-alpha (IFN alpha) results in tumor regression in a subset (< 20%) of patients with renal cell carcinoma, the underlying mechanisms for the resistance of renal cancer (RC) cells to IFN alpha is unknown. MATERIALS AND METHODS: We examined 5 RC lines resistant and 5 RC lines sensitive to the antiproliferative effects of IFN alpha for differences in: 1) the number of IFN binding sites, 2) the number of signal-transducing IFNAR-1 chains of the IFN alpha receptor, 3) IFN alpha receptor structure, 4) IFN-stimulated gene (ISG) expression and 5) IFN alpha sensitivity in antiviral assays. RESULTS: No structural alterations in the IFN alpha receptor were detected in any RC line examined, although varying numbers of ligand binding sites and IFNAR-1 signal transducer chains were present. All 5 IFN-sensitive, and 4 of 5 IFN-resistant RC lines were sensitive to the antiviral and gene-inducing actions of IFN alpha. CONCLUSIONS: The resistance of RC lines to IFN's antiproliferative action is not due to defects in ligand binding or in IFN-receptor structure. Our results indicate that the defective antiproliferative response in most RC cells is not due to their failure to induce the gene-inducing and antiviral effects of IFN alpha.

Antineoplastic Agents↗
PubMed1996

YAC cloning and identification of rice (Oriza sativa L.) genomic DNA.

Construction of the genomic library by using yeast artificial chromosomes (YAC) has been an approach to a map-based gene cloning strategy. We have obtained more than 2000 YAC clones for the construction of a rice (Oriza sativa L.) genomic library through a procedure that could be summarized as follows: a fractionate by the pulsed-field gel electrophoresis (PFGE), the rice nucleic high molecular weight (HMW) DNA which is partially digested with EcoRI, and recovered fragments larger than 200 kb; ligate the fragments to the EcoRI digested YAC vector pairs pJS97 and pJS98; transform competent spheroplasts prepared from yeast strain YPH252; and select transformants directly on Ura-Trp-double selective media. Southern hybridization results indicated that the sizes of inserts were in the range of 200-820 kb.

Chromosomes, Artificial, Yeast↗
PubMed1996

Object-oriented analysis and design of an ECG storage and retrieval system integrated with an HIS.

For a hospital information system, object-oriented methodology plays an increasingly important role, especially for the management of digitized data, e.g., the electrocardiogram, electroencephalogram, electromyogram, spirogram, X-ray, CT and histopathological images, which are not yet computerized in most hospitals. As a first step in an object-oriented approach to hospital information management and storing medical data in an object-oriented database, we connected electrocardiographs to a hospital network and established the integration of ECG storage and retrieval systems with a hospital information system. In this paper, the object-oriented analysis and design of the ECG storage and retrieval systems is reported.

Computers↗
PubMed1996

Cyclosporin A-induced changes in nitric oxide synthase activity in the rat kidney: in vitro and in vivo assay.

Cyclosporin A (CsA) is a cyclic undecapeptide that has been used extensively as an immunosuppressive drug in transplantation medicine and is known to interact with L-arginine dependent pathways. We studied the in vitro and in vivo effects of CsA on nitric oxide synthase (NOS) activity in the rat kidney. CsA in concentrations of 44-2200 nM in vitro, and 12.5 or 25 mg/kg body weight per 4 weeks treated rat kidneys in vivo, significantly stimulated NOS activity. CsA may alter the Ca2+/Cam-dependent NOS activity by interacting with rat kidney Ca2+/calmodulin dependent events.

Animals↗
PubMed1996

Spontaneous apoptosis in human colon tumor cell lines and the relation of wt p53 to apoptosis.

OBJECTIVE: To examine spontaneous apoptosis of cultured human colon tumor cell lines in vitro and to investigate the role of wild type (wt) p53 in regulation of apoptosis induced by DNA-damaging treatment. METHODS: A model system of human tumor progression involving three cell lines was used in this study for examination of apoptosis. They were originally established from human colon villous adenoma, including an early passage of non-tumorigenic cell line, V235E; a late passage of weakly tumorigenic cell line, V235L; and a spontaneous progressing highly tumorigenic cell line. V411. All of them maintain wt p53 expression. For identification of apoptosis, two tests were performed: 1. morphology study using acridine orange (AO)/ethidium bromide (EB) stainning by fluorescence microscopy; 2. DNA electrophoresis on agarose gel. P53 and WAF-1 (a downstream gene of p53) expressions were analysed at mRNA level using Northern blot technique. Apoptotic index of cell lines examined was measured by DNA fluorescence assay. RESULTS: Spontaneous apoptosis was demonstrated in cell lines of all stages of progression by both morphology and DNA agarose gel electrophoresis. Apoptosis was further induced in V411 after treatment of cells with 137Cs gamma-irradiation and accompanied by increases in p53 and WAF-1 expression. In contrast, a mutant p53 bearing human colon cancer cell line, sw480, lacked spontaneous apoptosis, and upon irradiation neither induction of apoptosis nor increase expression of p53 and WAF-1 were seen. CONCLUSIONS: Apoptosis can be maintained in some human tumor cell lines despite transformation and carcinogenesis. Wt p53 and WAF-1 products are two of the potential mediators which effect apoptosis. Additionally, since apoptosis was enhanced by irradiation in V411, but not in sw480, it suggests that wt p53 cancer cells are more sensitive to DNA-damaging treatment than mutant p53 cancer cells. These finding may have implications for cancer therapy.

Adenoma, Villous↗
PubMed1996

[Relationship between the express product of src gene (pp60c-src) and the initiation of gastric carcinoma].

The tissues of the fetal gastric epithelia, adult normal gastric epithelia, gastric epithelial lesions, gastric carcinoma and the tissues adjacent to carcinoma were studied immunohistochemically by using the specific monoclonal antibody of c-src gene express product (pp60c-src), MAb 327. The positive rates of pp60c-src in the fetal gastric epithelia, adult gastric epithelial inflammatory hyperplasia, intestinal glandular metaplastia and gastric carcinoma were 100.0% (12/12), 100.0% (30/30), 100.0% (16/16), 83.3% (40/48), respectively, all these pp60c-src positive rates were higher than that of adult normal gastric epithelia (60.0%, 12/20), a significant difference was noted statistically (P < 0.005). And there was statistical significant difference of pp60c-src express amount among different tissues (P < 0.005). The positive rates of pp60c-src in the intestinal and diffuse type gastric carcinomans were 100.0% (16/16) and 68.8% (22/32), respectively, a significant difference was found statistically (P < 0.025), the difference of pp60c-src express amount was significant (P < 0.05) but no significant differences of the positive rates and express amount of pp60c-src in the tissues adjacent to carcinoma of two types of carcinoma were found (P > 0.05). The results of this experiment indicated that the activation of c-src gene and increase of pp60c-src express were associated with the proliferation, turnover, transformation and malignant change of the gastric epithelial cells, with the initiation of the gastric carcinoma, and also with the differentiation and the histological types of the gastric carcinoma.

Adenocarcinoma↗
PubMed1996

Inhibition of rat brain nitric oxide synthase activity by cyclosporin-A.

Cyclosporin-A, a potent immunosuppressive agent is known to induce cellular toxic side effects by way of altering calcium homeostasis, including calcium/calmodulin mediated events. We studied the in vitro and in vivo effects of cyclosporin-A on rat brain nitric oxide synthase activity (the enzyme that mediates the conversion of L-arginine to citrulline and NO). CsA in concentrations of 22-4400 nM inhibited rat brain NOS activity in vitro and in 10 or 25 mg/kg wt/4 weeks of CsA treated rat brains in vivo. We report here that CsA by way of interfering with rat brain Ca2+/CaM mediated events may inhibit its NOS activity which ultimately may result in neurotoxicity.

Animals↗
PubMed1996

[The relationship between peripheral edema and right heart function in COPD induced cor pulmonale].

OBJECTIVE: To estimate the role of right heart function in the development of edema in COPD induced cor pulmonale. METHOD: 44 cases in exacerbation stage with hypoxia and hypercapnia were studied. Pulmonary hemodynamic parameters were measured by Swan-Ganz catheter and compared with the presence and extent of peripheral edema. RESULTS: Peripheral edema was noted in 40 cases and right arterial pressure < or = 1.33 kPa in 23 cases (23/40 = 57.5%), 17 cases showed edema, with right artrial pressure > 1.33 kPa. There was no significant difference in peripheral edema between that two groups. CONCLUSION: A high proportion of COPD patients with edema do not show right heart failure. The development of edema in COPD may be related to a complex mechanism, including hypoxia and hypercapnia induced natrium and water retention, Right heart failure is not a prerequisite for edema. The significance of edema in COPD induced cor pulmonale should be interpreted correctly in clinical practice.

Aged↗
PubMed1996

[Mechanism of plasma endothelin-1 level elevation and its relation with pulmonary hypertension in chronic cor pulmonale].

UNLABELLED: To explore the mechanism of plasma endothelin-1 (ET-1) level elevation and its relation with pulmonary hypertension in chronic cor pulmonale, plasma ET-1 level was measured by using radioimmunoassay in 21 cases of chronic cor pulmonale with acute exacerbation and cardiac catheterization was performed simultaneously. Results, Peripheral venous plasma ET-1 level of the patients was significantly higher than that of controls and also higher than that of peripheral arterial and pulmonary arterial plasma ET-1 level of the patients themselves. The plasma ET-1 level of patients had a significant negative correlation with PaO2 and SaO2 and positive correlation with mean pulmonary arterial pressure (PAPM) and pulmonary vascular resistance index (PVRI). 9 of the patients were treated with mechanical ventilation. After ventilation, PaO2 went up notably and plasma ET-1 level decreased remarkably, PAPM and PVRI also reduced simultaneously. CONCLUSIONS: The causes of plasma ET-1 level elevation in cor pulmonale may be as follows, Firstly, pulmonary alveolar hypoxia increases the release of ET-1 in lungs; Secondly, the ability of the lungs to clean ET-1 decreases because of pulmonary abnormality. High level of plasma ET-1 may induce pulmonary hypertension. The level of plasma ET-1 can be lowered by correcting hypoxic status of the patients and the resulting improvement of pulmonary hemodynamics.

Aged↗
PubMed1996

[Prognosis of patients with breast cancer related to the timing of operation during menstrual cycle: a report of 218 patients].

We have finished a retrospective study of 218 premenopausal patients who underwent primary surgery for operable breast carcinoma between March 1958 and December 1984. All these patients had available records of menstrual data and had been followed-up for more than 10 years. U-nivariate analysis showed that the menstrual timing of operation, as other known prognostic factors (tumor size, node status, histological grade, TNM classification, adjuvent systemic therapy, etc), had an influence on the patients' outcome. Multivariate analysis by Cox regression model indicated that disease-free rate and overall survival rate of patients operated during the periovulatory phase (days 7-20, 123 cases) were significantly superior to those during the perimenstrual phase (days 1-6 and 21-40, 95 cases) (P < 0.01). There were no significant differences in prognosis between patients who received their operations during the follicular phase (days 4-14, 96 cases) and those during the luteal phases (days 15-40, 122 cases) (P > 0.1). We suggest that the adequate timing of operation should be further determined by prospective, randomized clinical study.

Adult↗