Search PubMed⌕ Search

Biomedical subjects

W Zhou

Publications and source records attributed to W Zhou.

At least 433 records · Page 24Linked to original sources
PubMed1992

[Computerized image analysis for retinal nerve fiber layer: a preliminary report].

The principle and method for analysing the white-black photographs of retinal nerve fiber layer (RNFL) by using the technique of computerized image analysis were introduced. An objective and quantitative result of RNFL on the white-black photograph was initially obtained, and using the technique of fulse colour, each of the RNFL could be showed, which seem to have more advantages than observing RNFL on a white-black photograph.

Anthropometry↗
PubMed1992

Inhibitory effect of interferon and tumor necrosis factor on human luteal function in vitro.

OBJECTIVE: To investigate whether immunological mechanisms may be involved in human luteal function. DESIGN: The effects of the cytokines, interferon-alpha (IFN-alpha), interferon-gamma (IFN-gamma) and tumor necrosis factor alpha (TNF-alpha) on steroidogenesis by human luteal cells were examined in vitro. The dispersed human luteal cells, obtained from a total of 17 women at laparotomy, were cultured separately in the presence or absence of human chorionic gonadotropin (hCG) and IFNs/TNF-alpha with the medium being replaced at 48 hours. The medium was collected at 48 and 96 hours for steroid assays. RESULTS: The IFN-alpha had no significant effect on the production of estradiol or progesterone (P), whereas a dose-related inhibition of basal, as well as hCG-stimulated P formation, was observed after the addition of IFN-gamma (10 to 1,000 U/mL). Progesterone production was inhibited to about 45% of the control at 48 hours and even lower at 96 hours (n = 6, P < 0.001). The combination of IFN-gamma and low doses of TNF-alpha induced a further significant inhibition, whereas there was no effect of TNF-alpha alone. This inhibitory effect of IFN-gamma could be completely neutralized with a monoclonal antibody to IFN-gamma. Incubation with the antibody alone increased the production of P from luteal cells in culture, suggesting a local tonic inhibitory action of endogenous IFN-gamma. CONCLUSION: Interferon-gamma and TNF-alpha, whose function classically is known as antiviral, also may play a role in human luteal regression by inhibiting luteal P production.

Adult↗
PubMed1992

Inflammation and platelet-activating factor production during hepatic ischemia/reperfusion.

The role of platelet-activating factor as a potential mediator of hepatic inflammatory injury associated with liver ischemia/reperfusion was investigated using a partial no-flow model in rats in vivo. Platelet-activating factor levels of livers from sham-operated rats and from animals experiencing hepatic reperfusion for less than 6 hr were very low. They were observed to increase significantly after 12 hr of reperfusion and reached peak levels after a 24-hr reperfusion period, a time when maximal hepatic injury and inflammation occurred. Treatment of experimental rats with WEB2170, a platelet-activating factor receptor antagonist, attenuated the hepatic injury and inflammation, as evidenced by decreases in plasma ALT and in hepatocyte necrosis and neutrophil infiltration. Both inactivation of Kupffer cells with gadolinium chloride and inhibition of the formation of reactive oxygen species with allopurinol reduced platelet-activating factor production in the liver, whereas induction of neutropenia had no effect, suggesting that interaction of Kupffer cells with oxygen-derived free radicals may be a plausible mechanism for hepatic platelet-activating factor accumulation. It is concluded that platelet-activating factor contributes to the inflammatory consequences of ischemia/reperfusion underlying late-phase hepatic injury.

Alanine Transaminase↗
PubMed1992

Production of monoclonal antibody in hollow fiber culture system with serum-free medium.

Hybridoma cells 7E8, secreting mouse monoclonal antibody (McAb) IgG against potato virus X, were cultured in hollow fiber cell culture system (module VF-2) with serum-free medium 1640SFM. The maximum viable cell density was found to be 2.34 x 10(6) cells/ml that was 3.7 and 2.2 times as high as those achieved in spinner and static flask culture respectively. About 10,000ml of cell culture media had been collected in the cultural period of 42 days. The ELISA titer of the McAb in the media was about 1:20,000 that was 25 times as high as those attained from the cultures in either spinner or static flask. From 1,000ml of cell culture media, an amount of 51.2mg of 7E8 McAb IgG had been purified by 50% saturated ammonium sulfate precipitation and Sephadex G-200 chromatography. The average yield of McAb in the hollow fiber cell culture system was 12.3mg/day. The results of the study suggest that it is hopeful for hybridoma cell culture in the hollow fiber cell culture system with serum-free medium for McAb production on large-scale.

Antibodies, Monoclonal↗
PubMed1992

Mechanism of prevention of development of N-nitrosobis(2-oxopropyl)amine induced pancreatic carcinoma by a protein-free diet in hamsters.

It has been shown that feeding a protein-free diet prior to injection of N-nitrosobis(2-oxopropyl)amine (BOP) can inhibit the development of pancreatic carcinoma in the hamster. The purpose of this study was to determine whether this inhibition is due to a direct effect on the pancreas or to a systemic mechanism. Pancreas transplantation was used to create four groups of two-pancreas hamsters (Group 1: protein-containing diet donor/protein-containing diet host; Group 2: protein-containing diet donor/protein-free diet host; Group 3: protein-free diet donor/protein-containing diet host; Group 4: protein-free diet donor/protein-free diet host). Animals were fed either a protein-containing diet or a protein-free diet for four weeks preoperatively. One day after transplantation, the two-pancreas animals received a 40 mg/kg body weight, subcutaneous, single dose of BOP. Animals in all groups were maintained on a regular protein-containing diet postoperatively, and were then sacrificed 42 weeks after BOP injection. The results showed that a) the incidence of carcinoma in groups 2, 3, and 4 was significantly lower than that in group 1; b) there was no significant difference in group 2 between donor and host pancreas; c) the incidence of carcinoma in the donor pancreas was lower than that in the host pancreas in groups 3 and 4. These results confirm that the protein-free diet significantly inhibits the development of BOP induced pancreatic carcinoma in the hamster. The inhibitory effect appears to act both directly on the pancreas and through an indirect systemic mechanism.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenocarcinoma↗
PubMed1992

Role of platelet-activating factor in pancreatitis-associated acute lung injury in the rat.

Acute necrotizing pancreatitis induced by infusion of bile salt into the pancreatic duct in rats is consistently associated with acute lung injury similar to the adult respiratory distress syndrome. The role of platelet-activating factor (PAF) in this pancreatitis-associated remote organ failure (lung injury) was investigated. Pulmonary tissue levels of PAF were increased gradually and reached a level of 1345 +/- 455 pg/g (6 times the control level) at 12 hours after induction of pancreatitis, whereas pancreatic PAF levels were undetectable and blood PAF remained unchanged. This local pulmonary PAF accumulation occurred at approximately the same time as the progression of lung injury. Pulmonary responses detected (i.e., eicosanoid production, leukocytic infiltration, Evan's blue extravasation, beta-glucuronidase release) were attenuated to varying degrees by treatment of rats in which pancreatitis was initiated with the PAF receptor antagonists (WEB2170 and BN52021). Rat lung lavages were examined after a 12-hour course of pancreatitis and no changes in PAF concentration, surfactant content, and phospholipase A2 (PLA2) activity were noted. Intravenous administration of PLA2 promoted pulmonary PAF production in experimental rats with pancreatitis but not in normal rats. This observation indicates that PLA2, which was determined to be elevated in plasma during pancreatitis, may be responsible for the accumulation of PAF in the lung. In conclusion, pancreatitis-associated lung injury appears to result from an endogenous inflammatory response in which PAF may play an important role.

Animals↗
PubMed1991

Guatemalan human onchocerciasis. I. Systematic analysis of patient populations, nodular antigens, and specific isotypic reactions.

The population from five Guatemalan plantations in areas endemic for onchocerciasis was surveyed, and 1032 individuals were recruited to participate in our study. From physical examination, past clinical history (5 to 8 yr), laboratory evidence and sample availability, a group of 778 long term residents with confirmed disease status were selected for detailed examination. We were able to identify 268 long term residents of endemic areas who had never been infected, 44 of these are from hyper- and mesoendemic areas. The 44 uninfected individuals from the hyper- and mesoendemic areas, because of their considerable exposure to this disease, were classified as "putatively immune." Intact nodules containing adult worms of Onchocerca volvulus were homogenized in the presence of protease inhibitors and fractionated into particulate and aqueous isotonic soluble antigens. Systematic analysis of these Ag fractions showed considerable amounts of Ig, presumably associated with Ag in the form of immune complexes. Individual specific antibody reactions from all 778 patients to nodule Ag were examined. Reactions to O. volvulus antigens by antibodies from patients with confirmed parasitic infections were almost exclusively restricted to IgG1 and IgG4 isotypes. Antigenic activity appeared to be primarily associated with low molecular mass (14 to 29 kDa) components. Some competitive blocking of antibody activities of other isotypes by IgG1 was observed, most notable was that of IgG3 and IgA. IgG4 and IgM activities were not significantly blocked.

Adolescent↗
PubMed1991

Guatemalan human onchocerciasis. II. Evidence for IgG3 involvement in acquired immunity to Onchocerca volvulus and identification of possible immune-associated antigens.

Ag-specific isotypic differences in immune response to Onchocerca volvulus Ag were assessed for 778 long term residents of endemic Guatemalan areas by quantitative ELISA with 5-min incubation steps and immunoblot. The study population was separated into five groups based on clinical status: N+F+, N+F-, N-F+, N-F-H+, and N-F-H-, where N = O. volvulus adults (nodule), F = microfiladermia, and H = history of O. volvulus infection. A subset of 44 individuals with high exposure to onchocerciasis from the N-F-H- group were critically evaluated and designated as "putatively immune." IgG1 reactivity to O. volvulus Ag was elevated in the majority of infected persons, but not in putatively immune individuals. Specific IgG3 levels, however, were equally elevated in all groups. The majority of N+F- persons also had elevated IgG1 levels, but they were lower than those found in F+ persons. IgG3 reactivities to a group of antigens at 20 kDa (GP20) were seen in many uninfected persons and some N+F- persons. In contrast, most F+ persons, react to this Ag with IgG1 and not IgG3. A mangabey inoculated with the infectious larval stage of O. volvulus (L3), but showed no signs of infection, began to recognize GP20 at 2 wk postinoculation. Early recognition of GP20 was possibly elicited by the larval stage. Purified nodule Ag from N+F+ individuals contained GP20, however, identical nodule Ag prepared from N+F- individuals did not. These data suggest that GP20 Ag may be common to both uterine microfilaria and the infectious larval stages. The fact that GP20 is predominantly recognized by IgG3 in putatively immune persons and some N+F- persons suggests that this increased IgG3 activity may be important in acquired immunity to onchocerciasis.

Adolescent↗
PubMed1991

Optimization of binding capacity and specificity of protein G on various solid matrices for immunoglobulins.

Streptococcal protein G is a more versatile and efficient alternative to staphylococcal protein A in purifying immunoglobin G (IgG) isotypes from various animal species. Optimizations are most dramatic with goat IgG, which binds protein G 55 times better than protein A. Using GammaBind G (a recombinant form of protein G (Genex Corp.)), we optimized binding capacity and specificity for IgG. Protein G was covalently coupled to three different matrices (CNBr-Sepharose, Tresyl-Sepharose, and Affigel-10) and compared with protein A-CNBr-Sepharose. Equal volumes of human, mouse, and goat serum samples were equilibrated into Hepes/NaOH buffers with various ionic strengths (i.e., concentrations of NaCl) and pH values and allowed to bind to affinity columns of proteins G and A. Bound ligands were eluted with 8.0 M urea, 0.05-M Tris/HCl, pH 8.00. Bound fractions were assayed for protein concentration and analyzed by sodium dodecyl sulfate polyacrylamide electrophoresis. The optimal conditions for binding IgG to protein G are 1.0 M NaCl and pH 8.0 for human, mouse, and goat.

Animals↗
PubMed1991

Efficacy of the immunoblot assay for cysticercosis in pigs and modulated expression of distinct IgM/IgG activities to Taenia solium antigens in experimental infections.

A recently invented immunoblot assay for human cysticercosis was evaluated for efficacy in pigs. The test population consists of 45 pigs with parasitologically confirmed cysticercosis, 47 with heterologous infections, 45 SPF or concrete raised control animals. With this group of 137 animals the test performance was 100% sensitive and 100% specific. The antigen-specific responses of immunoglobulin A (IgA), IgG and IgM in four pigs infected with Taenia solium eggs derived from a human were quantified by immunoblot. Antigen-specific activities were observed as early as 1 week postinfection. The first antigen-specific isotypic response was IgM antibodies directed against a glycoprotein at 97 KD (GP97). This activity generally disappeared between the sixth and ninth week postinfection. Between Weeks 5 and 8, IgG activity rose as IgM activity fell. The IgG activity, however, was directed mostly towards GP50 and GP42 antigens. If the same response occurs in people with cysticercosis, identifying specific isotype activity may help to distinguish new infection from old.

Animals↗
PubMed1991

Bleomycin A2 and B2 purification by flash chromatography for chemical and biochemical studies.

The clinically used formulation of the anticancer antibiotic, Blenoxane, is a mixture of bleomycin congeners. A new approach to separating the major A2 and B2 congeners has been developed utilizing the flash chromatography technique. A 5-6-inch column of fine mesh silica gel with a solvent system of 1% ammonium formate:methanol (2:3) was used. Low air pressure was applied to the column to increase the flow rate such that separation was complete in approximately 20 min. Reverse phase size exclusion gravity chromatography with Sephadex G-15 column bedding was an effective, rapid procedure for removal of the 1% ammonium formate, the lowest percentage practical for separating the bleomycins. This separation approach does not damage the antibiotics, as demonstrated by NMR spectroscopy, thin layer chromatography, and DNA cleaving activity. Although not as useful for detection of trace amounts of the drug in biological systems as some of the known HPLC methods, this method is excellent for separating large quantities of the drug (8-32 mg) in order to obtain congeners pure enough for synthetic, biochemical, and biophysical studies.

Bleomycin↗
PubMed1991

[Flow cytometric DNA analysis and its relationship with pathology and prognosis in lung carcinoma].

DNA content of paraffin-embedded tumour material from 110 patients with lung carcinoma was measured by means of flow cytometry. Aneuploidy was found in 78% of the patients. The mean DNA ploid, the percentage of hyperdiploidy and the percentage of multiploidy in small cell carcinoma and large cell carcinoma were higher than those obtained in squamous cell carcinoma and adenocarcinoma. These values were also higher in grade III squamous cell carcinoma and adenocarcinoma as compared with grade I and II squamous cell carcinoma, and adenocarcinoma. They were also higher in lung carcinoma with the primary tumor size greater than or equal to 3 cm than that less than 3 cm. The five-year survival rate and mid mean survival time of patients with hyperdiploidy were significantly lower than those of patients with diploidy and hypodiploidy. Conclusively, DNA content is considered closely related to the degree of malignancy of lung carcinoma and may be adapted as a reliable criterion in estimating the prognosis of lung carcinoma.

Adenocarcinoma↗
PubMed1991

[Isolation and purification of alpha fetal protein utilizing Act-Ultrogel AcA 22 affinity chromatography].

In the present communication, we report a method for the isolation and purification of alpha FP from fetal corpse homogenate in a single-step procedure using Act-Ultrogel AcA 22 affinity chromatogrpahy column. This method proves to be better than the conventional method in simplicity, fastness and validity with recovery, purity and immunoreactivity. The immunoreactivity of the purified alpha FP labelled by the method of Hunter and Greenwood (1962) was 50-60% (B/T%). This was similar to alpha FP standard (WHO). The results indicate that the 125I-alpha FP is suitable for alpha FP radioimmunoassay.

Chromatography, Affinity↗
PubMed1991

[Comparison of Spatholobus suberectus Dum, Euonymus alatus (Thunb.) Sieb. and Eupolyphaga sinensis Walker on regulation of plasma lipid].

The Spatholobus suberectus (SS) of hexue type, the Euonymus alatus (EA) of huoxue type and the Eupolyphaga sinensis (ES) of poxue type were selected and their influence on plasma lipid in the experimental hyperlipidemia quails was observed. The ES could raise plasma HDL-C/TC ratio and increase LCAT activity. The SS could raise plasma HDL2-C/HDL3-C ratio. The effect of EA on plasma HDL-C/TC, HDL2-C/HDL3-C and LCAT levels was between SS and ES. All the three huoxue huayu Chinese drugs could lower plasma HDL3-C level and slow down the progress of atherosclerosis to a certain degree. The above-mentioned results show that certain orders exist between the action range of huoxue huayu drugs and their effect on regulating plasma lipid.

Animals↗
PubMed1991

[The preparation of highly purified insulin and its clinical use. Insulin Cooperative Study Group].

Antigenicity of insulin preparations is obviously related to their purity. The average contents of proinsulin, glucagon and pancreatic polypeptide in highly purified insulin (HP-I) produced by us are 76.0, 2.11 and 0.11 ppm respectively. These results are superior to those for domestic conventional crystalline insulin and single peak insulin (SP-I). The antibodies to insulin, proinsulin and pancreatic polypeptide in serum were examined in 24 diabetic patients treated with HP-I for more than 6 months. The positive rates for the above three antibodies were 37.5%, 0% and 0% respectively. The results showed that the antigenicity of HP-I was much lower than that of domestic conventional crystalline insulin and almost the same as that of MC-I from Nordisk, Denmark.

Autoantibodies↗