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Biomedical subjects

F Wang

Publications and source records attributed to F Wang.

At least 289 records · Page 16Linked to original sources
PubMed1999

Islet amyloid polypeptide tonally inhibits beta-, alpha-, and delta-cell secretion in isolated rat pancreatic islets.

Islet amyloid polypeptide (IAPP, or amylin) is produced in pancreatic beta-cells. The intraislet significance of IAPP is still uncertain. In the present study, paracrine effects of endogenous IAPP and somatostatin were investigated in isolated rat pancreatic islets. The intraislet IAPP activity was inhibited with an IAPP antiserum or a specific antagonist [IAPP-(8-37)]. Somatostatin activity was inhibited by immunoneutralization. Basal insulin and glucagon secretion were not affected by the somatostatin and/or IAPP blockade. Arginine-stimulated insulin and glucagon secretion were dose dependently increased by IAPP antiserum, IAPP-(8-37), and somatostatin antiserum, respectively. Arginine-stimulated somatostatin secretion was dose dependently potentiated by IAPP antiserum. Insulin secretion induced by 16.7 mM glucose was enhanced by IAPP antiserum and IAPP-(8-37), respectively. A combination of somatostatin antiserum with IAPP antiserum or IAPP-(8-37) further enhanced the arginine-stimulated insulin and glucagon secretion compared with effects when the blocking reagents were used individually. These results indicate that endogenously produced IAPP tonally inhibits stimulated insulin, glucagon, and somatostatin secretion. Furthermore, the paracrine effects of IAPP and somatostatin are additive.

Amyloid↗
PubMed1999

Effect of streptozotocin-induced diabetes mellitus on type 1 deiodinase (D1) in inherited D1-deficient mice.

We investigated the effects of streptozotocin (STZ)-induced diabetes on thyroid hormone levels, type 1 deiodinase (D1) activity and messenger RNA (mRNA) levels in inherited D1 deficient C3H mice in a comparative manner with control C57 mice. The apparent maximum velocity (Vmax) D1 values in C3H mice were 3% (liver) and 26% (kidney) of those in C57 mice. In C3H mice, similar serum T3, slightly higher T4, and 2.6-fold higher rT3 levels were observed compared with C57 mice. In STZ-induced diabetes, serum T4 level markedly decreased in both C3H and C57 mice. Serum T3 levels in STZ-C3H mice similarly decreased as in STZ-C57 mice. On the other hand, serum rT3 levels increased to 3.3-fold higher in STZ-C3H than in STZ-C57 mice. The Vmax values were decreased to 12% (STZ-C3H) and to 30% (STZ-C57) in liver, and decreased to 33% (both STZ-C3H and STZ-C57) in kidney. The changes in D1 mRNA levels in diabetes versus control were comparable to those of D1 activities in both strains. In summary, similar mechanism(s) to those which decrease the D1 expression and the serum T3 level in diabetes, function in D1 deficient C3H mice as in C57 mice. It appears that hepatic and renal D1 activity alone can not explain the similar reduction in T3 level in STZ-C3H mice and STZ-C57 mice.

Animals↗
PubMed1999

Phase I trial of a MART-1 peptide vaccine with incomplete Freund's adjuvant for resected high-risk melanoma.

Twenty-five patients with high-risk resected stages IIB, III, and IV melanoma were immunized with a vaccine consisting of the minimal epitope, immunodominant 9-amino acid peptide derived from the MART-1 tumor antigen (AAGIGILTV) complexed with incomplete Freund's adjuvant. The last three patients received the MART-1(27-35) peptide with incomplete Freund's adjuvant mixed with CRL 1005, a block copolymer adjuvant. Patients were immunized with increasing doses of the MART-1(27-35) peptide in a Phase I trial to evaluate the toxicity, tolerability, and immune responses to the vaccine. Immunizations were administered every 3 weeks for a total of four injections, preceded by leukapheresis to obtain peripheral blood mononuclear cells for immune analyses, followed by a post-vaccine leukapheresis 3 weeks after the fourth vaccination. Skin testing with peptide and standard delayed-type hypersensitivity skin test reagents was also performed before and after vaccinations. Local pain and granuloma formation were observed in the majority of patients, as were fevers or lethargy of grade 1 or 2. No vaccine-related grade III/IV toxicity was observed. The vaccine was felt to be well tolerated. Twelve of 25 patients were anergic to skin testing at the initiation of the trial, and 13 of 25 developed a positive skin test response to the MART-1(27-35) peptide. Immune responses were measured by release of IFN-gamma in an ELISA assay by effector cells after multiple restimulations of peripheral blood mononuclear cells in the presence of MART-1(27-35) peptide-pulsed antigen-presenting cells. An ELISPOT assay was also developed to measure more quantitatively the change in numbers of peptide-specific effector cells after vaccination. Ten of 22 patients demonstrated an immune response to peptide-pulsed targets or tumor cells by ELISA assay after vaccination, as did 12 of 20 patients by ELISPOT. Nine of 25 patients have relapsed with a median of 16 months of follow-up, and 3 patients in this high-risk group have died. Immune response by ELISA correlated with prolonged relapse-free survival. These data suggest a significant proportion of patients with resected melanoma mount an antigen-specific immune response against a peptide vaccine and support further development of peptide vaccines for melanoma.

Antigens, Neoplasm↗
PubMed1999

Influencing physician prescribing.

The drug use process suffers from problems related to quality and cost that have not responded well to administrative or educational interventions. In many cases, attempts to improve the quality of physician prescribing have been clumsy, often based on intuition. This article begins by describing the drug use process and the role of prescribing in that process. In the following section, we describe what is known about how physicians make drug choice decisions. The paper concludes with suggestions, based on evidence, about the design of strategies for influencing prescribing.

Advertising↗
PubMed1999

[Effects of castor oil-diet on the synthesis of prostaglandin E2 in pregnant rats].

OBJECTIVE: To determine effects of castor oil-diet on the synthesis of prostaglandin E2(PGE2) and explore the mechanism of labor induced by castor oil-diet in pregnant rats. METHODS: Pregnant rats were gavaged castor oil-diet in 18 and 19 days of gestation. At the time of death, blood of portal and peripheral veins, intestinal mucosa, amnion, amniotic cells and placenta were collected, and the tissues were cultured in the presence of ricinoleic acid or indomethacin. The concentrations of PGE2 in the media or blood were measured by RIA methods. RESULTS: The PGE2 levels in the portal vein increased, while the PGE2 levels in peripheral blood had no changes significantly, the PGE2 levels in the tissues of the intestinal mucosa, placenta, amnion and amniotic cells were increased significantly; Ricinoleic acid stimulated the synthesis of PGE2 in the above tissues in vitro, which had the positive correlations with the dose of ricinoleic acid and its lasting time. Indomethacin inhibited the synthesis of PGE2 in-vitro. CONCLUSION: The increased synthesis of PGE2 in the intrauterine tissues is a key of the initiation of labor induced by castor oil-diet, and ricinoleic acid in castor oil-diet might be the active component which induced the initiator of labor.

Animals↗
PubMed1999

Transvenous pectoral implantation of single lead implantable cardioverter defibrillator.

OBJECTIVE: To report our initial experience of transvenous pectoral implantation of single lead implantable cardioverter defibrillator (ICD) in fifteen patients. METHODS: Fifteen patients (male 13, female 2, mean age of 51.7 years), including dilated cardiomyopathy in 4, hypertrophic cardiomyopathy in 2, coronary artery disease in 5 and syncope of unknown etiology in 2, underwent ICD implantation. Indications for ICD implantation were ventricular fibrillation (8 patients) and refractory ventricular tachycardia (7 patients). All patients had syncope out of hospital. The ICD system were Medtronic Jewel active can in 5 patients (Model 7219C in 2, 7220C in 3) and CPI Ventak PRxIII in 9 patients. For active can, shocks were delivered through distal coil to ICD shell and for PRxIII through the endotak lead of proximal to distal coil. Successful implantation criteria was 2 consecutive defibrillation at less than 24 J. RESULTS: All 15 patients had successful implantation using single lead ICD system in catheter laboratory. The mean defibrillation threshold was 12.8 J (5-15 J) and R wave was 9.9 mV (3.7-14.6 mV). All devices were of pectoral implantation. No operative and perioperative complications occurred. In 7.6 months (1-18 months) of follow-up, 3 patients had VT terminated by antitachycardia pacing (ATP) and 1 patient VF terminated by shock. CONCLUSION: Transvenous pectoral implantation of single lead ICD is easy to perform and has high defibrillation efficacy and should be a preferred approach.

Defibrillators, Implantable↗
PubMed1999

[P-selectin and tachykinins in bronchial hyperresponsiveness of asthma].

OBJECTIVE: The characteristic feature of asthma is bronchial hyperresponsiveness (BHR). It is due predominately to inflammation of airways. Pathologically, there are inflammatory infiltration, epithelial sloughing and mucosal edema in the bronchi. The objective of this study is to investigate the relationship between BHR and airway inflammation. METHODS: 57 cases of asthma and 22 normal subjects were tested with bronchial reactivity examination and P-selectin, substance P (SP) and vasoactive intestinal peptide (VIP) in plasma. RESULTS: It was found that the bronchial reactivity to inhaled methacholine was positive in 53 of the 57 asthmatic patients (92.98%), while the remaining four were negative (7.02%). Twenty-two normal subjects were all negative with the test of bronchial reactivity. The levels of P-selectin and SP in asthmatics with corticosteroids treatment (n = 27) were higher than those in the control group (P < 0.05), but lower than those in asthmatics treated with aminophylline and salbutamol sulfate (n = 30), (P < 0.01). The concentration of VIP in asthmatics with corticosteroids treatment was significantly higher than that of asthmatics with out corticosteroids treatment (P < 0.01) but lower than that in the control group (P < 0.01). There was positive relationship between bronchial reactivity and P-selectin (r = 0.328, P < 0.05), as well as SP (r = 0.529, P < 0.01) in asthmatics, but negative relationship between bronchial reactivity and VIP (r = -0.419, P < 0.05). CONCLUSION: The increase of P-selectin and SP and decrease of VIP can induce BHR, corticosteroids can reduce levels of P-selectin, SP and enhance the level of VIP, therefore it can improve the reactivity of airway and relieve symptoms.

Adult↗
PubMed1999

[Surveillance of bacterial resistance in Shanghai in 1998].

OBJECTIVE: To investigate the resistance of clinical bacterial isolates as a reference for rational use of antibiotics. METHODS: Using Kirby-Bauer method for bacterial susceptibility testing and NCCLS 1997 as assessment criteria. RESULTS: The number of Gram positive organisms was increasing in clinical isolates. Among the Staphylococci aureus (SA) and coagulase negative Staphylococci (CNS), methicillin resistant SA (MRSA) and methicillin resistant CNS (MRCNS) accounted for 70.7% and 54.9% respectively, but no vancomycin resistant strain was found. Vancomycin-resistant Enterococci was about 5%. Resistant rates of Klebsiella spp, Serratia spp, Enterobacter spp and Acinetobacter spp against third generation cephalosporins and fluoroquinolones increased markedly. The resistant rates of most Enterobacteriaceae species against imipenem were increasing gradually, while the resistant rates of Pseudomonas aeruginosa against ceftazidime, cefoperazone and imipenem were significantly higher as compared with the data in 1994. CONCLUSION: The urgent need of restricting the misuse of antibiotics.

Anti-Bacterial Agents↗
PubMed1999

[The characteristics and management of shotgun wounds of the extremities].

OBJECTIVE: To discuss the characteristics, classification and the problem of management for shotgun wounds of the extremities. METHODS: 82 shotgun wounds of the extremities, classified according to the modified rule form Sherman and Ordog's, were treated by "incision and drainage" initially, and were closed in primary, delay and later phase. The fractures were fixed by plaster, external fixator, simple internal fixator or plate fixation. Vascular injury was repaired by suture end-to-end or autograft. The injured nerves were treated in the primary or later period. RESULTS: The rate of infection was the highest in the primary closed wound, and the healing time was the longest in the later closed wound. The rate of infection was much higher in the fracture fixed by plate than the others. The results of nerve recovery in primary repair were not significantly different (except 2 case infection) from those in the later repair. CONCLUSIONS: A significant difference was noted between shotgun wound and other wound. Removal of wadding, prevention of fascial compartment syndrome, repeat planned exploration of wound, proper wound closing, external fixation of fracture, vascular debridement before anastomosis and delayed nerves repair contribute to a successful outcome in patients with extremity shotgun wounds.

Adolescent↗
PubMed1999

[Can esophagogastric anastomosis prevent gastroesophageal reflux].

OBJECTIVE: To investigate the possible anti-reflux function of esophagogastric anastomosis in the patients after receiving resection of cardiac cancer. METHODS: One hundred and ninety-two patients were studied by video-assisted gastroscopy, manometry, 24-h pH esophageal monitoring, radioscintigraphy and scanning electron microscopy. RESULTS: Abnormalities were found in 90.2% of patients through endoscopy. Resting pressure in esophageal body was higher than that in normal controls, and in the stomach, lower. Twenty-four hour pH monitoring demonstrated that gastroesophageal reflux (GER) did not occur when the patients slept in semi-reclining position, and occurred in all patients when slept in supine position. Scintigraphic study showed that 2/3 of the patients had reflux, occurrence of which was not affected by the length of postoperative period. Scanning electron microscopic examination showed that degeneration, exfoliation of esophageal mucosal epithelial cell, and derangement of micro-fold and inflammatory oedema of cytomembrane may be directly caused by reflux. CONCLUSIONS: GER exists in the majority of the patients after esophagogastrectomy and esophagogastrostomy for cardiac cancer. The occurrence of GER is not affected by the length of postoperative period. Some detecting methods fail to show the existence of GER, and 24-h pH monitoring is the most reliable method for detecting GER. Sleep in semireclining position is an effective method of preventing GER in postoperative patients.

Adult↗
PubMed1999

[Protect intercellular communication of pigment epithelium after laser photocoagulation].

OBJECTIVE: To observe the protective effect on the intercellular communication of retinal pigment epithelial (RPE) cells of dexamethasone (Dex) and verapamil (Ver) at different concentrations after laser photocoagulation. METHOD: Ten pig eyes were used to culture pig pigment epithelium cells. Use different concentrations of Dex and Ver to incubate cultured RPE cells 2 hours before laser coagulation, and then measure the intercellular communication function of confluent cells surrounding the coagulation spots after photocoagulation. RESULT: 125 mg/L Dex and 20 mg/L Ver could protect the intercellular communication of RPE cells under laser photocoagulation. The high concentration of drugs had better result. CONCLUSION: Both Dex and Ver can preserve the intercellular communication in vitro. The protective capacity is related to the concentration of drug.

Animals↗
PubMed1999

[Ultrastructural characteristics of epiretinal membranes].

OBJECTIVE: To investigate ultrastructural features and the correlation between the cell activation and extracellular matrix (ECM) expression of epiretinal membranes. METHODS: Immuno-electron-microscopy was done on the epiretinal membranes removed by vitrectomy from 16 patients with rhegmatogenous retinal detachment associated with proliferative vitreoretinopathy (PVR). The specimens were stained with antibodies to ECM proteins, including type I collagen, type III collagen and fibronectin (FN). RESULTS: A type of cells with a number of lamellipodia was found in membrane sections of 9 patients. The lamellipodia appeared to be either coiled or branched and were surrounded by abundant collagen fibers of type I and III. The cells with lamellipodia varied in their phenotypes and with or without pigment. There were dense gold particles of FN in contact regions of lamellipodia and collagen. CONCLUSIONS: Our observations support that the contraction of epiretinal membranes is the result of an interaction between cells and collagen, and the cells extending lamellipodia may initiate contractile events. FN is responsible for this contractile action.

Collagen Type I↗
PubMed1999

[The expression of IGF-I, TGF beta and Fas-L in granulosa cells of ovarian follicle with relation to the onset of atresia in rats].

This study was designed to investigate the effects of IGF-I, TGF beta and Fas-L on the sustaining of granulosa cells of ovarian follicle and the modulation of apoptosis of those cells, and to understand the molecular mechanisms of ovarian follicle atresia. Paraffin-embedded sections of SD rat ovary were made. Both TUNEL method and PCNA immunohistochemistry were employed to recognize atretic and healthy follicles. The expression of IGF-I, TGF beta, Fas-L and their receptors was displayed by immunostaining. The results showed that most of the granulosa cells within the healthy preantral and antral follicles were PCNA(+). At the early stage of atretic antral follicle, more than 5 granulosa cells were labelled by TUNEL method, and some granulosa cells were PCNA(+). At the late stage of atretic antral follicle, were labelled by TUNEL method. The immunoreactive products of IGF-I, IGF-IR, TGF beta, TGF beta R, Fas and Fas-L could be seen in the granulosa cells of healthy antral follicles. But, Granulosa cells were only TGF beta, TGF beta R and Fas immunopositive in all atretic antral follicles. In conclusion, combination of TUNEL method and PCNA immunochemistry is of benefit for distinguishing atretic follicles from healthy follicles. IGF-I might play an important role in stimulating proliferation of the granulosa cells and sustaining them. The lower expression or disappearance of IGF-I in the antral follicle might cause the onset of atresia. TGF beta, Fas-L and Fas might mediate apoptosis of the granulosa cells in antral follicles, causing follicle atresia. But, their effects of mediation could be inhibited as IGF-I exists in the follicles.

Animals↗
PubMed1999

[Effect of transforming growth factor-beta on proliferation cycle of epiphyseal chondrocyte].

In order to investigate the effect of transforming growth factor-beta (TGF-beta) on chondrocyte proliferation cycle, we used flow-cytometry to assess the epiphyseal chondrocyte of embryonic chick femora which was cultured in free-serum media and treated with TGF-beta. The results showed that after treated with TGF-beta for 24 h, the proliferation indexes(PIs) of experimental groups(0.11 ng, 0.33 ng, 1.00 ng/ml) were lower than the PIs of the control groups, but the PI of 3.00 ng/ml group was higher than that of the control group (P < 0.001). After treated for 48 h, except the 0.11 ng/ml group, the PIs of experimental groups were lower than those of the control (P < 0.001). And after treated for 96 h, the PIs of all groups were higher than those of the control; the PI of the 0.33 ng/ml group was the highest (P < 0.001). These suggest that after treated in varied time and dosage, the effect of TGF-beta on epiphyseal chondrocyte is obvious, and TGF-beta on epiphyseal chondrocyte is obvious, and TGF-beta can inhibit chondrocyte proliferation first, and then its effect on chondrocyte can transform from inhibition into proliferation.

Animals↗
PubMed1999

[Determination of glycyrrhizic acid in glycyrrhiza preparations with capillary electrophoresis and high performance liquid chromatography].

High performance liquid chromatography (HPLC), capillary zone electrophoresis (CZE) and micellar electrokinetic capillary chromatography(MECC) have been used to determine glycyrrhizic acid in glycyrrhiza preparations. By HPLC, mobile phase was V(methanol):V(water):V(acetic acid) = 75:23.5:1.5. By CZE, experiment was performed with 15 kV power, 0.075 mm i.d. x 800 mm fused-silica capillary column and UV detector. Samples were injected into the capillary by electromigration injection for 20 s. Absorbance detection was at 254 nm. The running buffer was made up of 0.02 mol/L dipotassium hydrogenphosphate and borax (pH 9.0). By MECC, the running buffer was made up of 0.025 mol/L sodium dodecyl sulfate (SDS), 0.02 mol/L dipotassium hydrogenphosphate and borax (pH 9.0). Each new capillary was washed with 0.1 mol/L NaOH, deionized water and buffer, each for 3 min, before use. Comparison of the results of analysis with HPLC, CZE and MECC has been made. It was found that result of MECC was very close to that of HPLC. MECC has been satisfactorily applied to plant drug analysis.

Chromatography, High Pressure Liquid↗
PubMed1999

[Morpholgical, histological and histochemical observations on the effect of albendazole on encysted larvae of Trichinella spiralis in mice].

AIM: To study the mechanism of action of albendazole on encysted larvae of Trichinella spiralis in mice. METHODS: Twelve Kunming strain mice each infected with 200 T. spiralis larvae were equally divided into two groups. Six mice of the treatment group were treated with 30 mg of albendazole/kg daily for 5 days. Morphological, histological and histochemical methods were used. RESULTS: The encysted larvae of albendazole-treated group became significantly damaged, most worms were shrunken and surrounded by inflammatory cells. Histochemical study demonstrated that the glycogen and RNA content of the larvae in the treated group was decreased, the activities of SDH, ATPase, ACP were lower than those of the control group. CONCLUSION: Albendazole can affect the physiological function of Trichinella spiralis.

Albendazole↗