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W C Wang

Publications and source records attributed to W C Wang.

At least 145 records · Page 8Linked to original sources
PubMed1989

First identification of acute tetrodotoxin-associated food poisoning in Taiwan.

Attempt was made to elucidate the responsible toxin in fish which recently caused food poisoning in Ilan County, Taiwan. The causative fish was assayed for anatomical distribution of toxicity (as tetrodotoxin). The roe showed the highest toxicity (1200 mouse units per gram, abbreviated as MU/g), followed by the dermis (150 MU/g) and muscle (120 MU/g). The toxins were partially purified from the methanolic extracts of the fish muscle and roe by ultrafiltration and Bio-Gel P-2 column chromatography. Thin-layer chromatography, cellulose acetate membrane electrophoresis and high performance liquid chromatography analysis demonstrated that the toxins consisted of tetrodotoxin and anhydrotetrodotoxin. It was concluded that the causative agent of the above food poisoning was tetrodotoxin.

Animals↗
PubMed1988

Cholinergic synaptic vesicle heterogeneity: evidence for regulation of acetylcholine transport.

Crude cholinergic synaptic vesicles from a homogenate of the electric organ of Torpedo californica were centrifuged to equilibrium in an isosmotic sucrose density gradient. The classical VP1 synaptic vesicles banding at 1.055 g/mL actively transported [3H]acetylcholine (AcCh). An organelle banding at about 1.071 g/mL transported even more [3H]AcCh. Transport by both organelles was inhibited by the known AcCh storage blockers trans-2-(4-phenylpiperidino)cyclohexanol (vesamicol, formerly AH5183) and nigericin. Relative to VP1 vesicles the denser organelle was slightly smaller as shown by size-exclusion chromatography. It is concluded that the denser organelle corresponds to the recycling VP2 synaptic vesicle originally described in intact Torpedo marmorata electric organ [Zimmermann, H., & Denston, C.R. (1977) Neuroscience (Oxford) 2, 695-714; Zimmermann, H., & Denston, C.R. (1977) Neuroscience (Oxford) 2, 715-730]. The properties of the receptor for vesamicol were studied by measuring binding of [3H]vesamicol, and the amount of SV2 antigen characteristic of secretory vesicles was assayed with a monoclonal antibody directed against it. Relative to VP1 vesicles the VP2 vesicles had a ratio of [3H]AcCh transport activity to vesamicol receptor concentration that typically was 4-7-fold higher, whereas the ratio of SV2 antigen concentration to vesamicol receptor concentration was about 2-fold higher. Based on an antibody standardization, in a typical preparation the VP1 vesicles contained 237 +/- 15 pmol of receptor/mg of protein whereas VP2 vesicles contained 102 +/- 3 pmol of receptor/mg of protein, and VP2 vesicles transported AcCh 2-3-fold more actively than VP1 vesicles.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗
PubMed1988

The immobilized leukoagglutinin from the seeds of Maackia amurensis binds with high affinity to complex-type Asn-linked oligosaccharides containing terminal sialic acid-linked alpha-2,3 to penultimate galactose residues.

We recently reported that the purified leukoagglutinin (designated MAL) from the seeds of the leguminous plant Maackia amurensis is a potent leukoagglutinin for the mouse lymphoma cell line BW5147 (Wang, W.-C., and Cummings, R. D. (1987) Anal. Biochem. 161,80). We and others have shown that this lectin is a weak hemagglutinin of human erythrocytes (Kawaguchi, T., Matsumoto, I., and Osawa, T. (1974) J. Biol. Chem. 249, 2786). We now report that leukoagglutination by MAL is inhibited by low concentrations of 2,3-sialyllactose (NeuAc alpha 2,3Gal beta 1,4Glc), but it is not inhibited by either 2,6-sialyllactose (NeuAc alpha 2,6Gal beta-1,4Glc), lactose, or free NeuAc. To further study the carbohydrate-binding specificity of this lectin, we investigated the interactions of immobilized MAL with glycopeptides prepared from the mouse lymphoma cell line BW5147 and from purified glycoproteins. We found that immobilized MAL interacts with high affinity with complex-type tri- and tetraantennary Asn-linked oligosaccharides containing outer sialic acid residues linked alpha 2,3 to penultimate galactose residues. Glycopeptides containing sialic acid linked only alpha 2,6 to penultimate galactose did not interact detectably with the immobilized lectin. Our analyses indicate that the interactions of complex-type Asn-linked chains with the lectin are dependent on sialic acid linkages and are not dependent on either the branching pattern of the mannose residues or the presence of poly-N-acetyllactosamine sequences.

Agglutination↗
PubMed1988

Lymphocyte and complement abnormalities in splenectomized patients with hematologic disorders.

Twenty-two patients, splenectomized 1 to 26 years earlier for hematologic disorders, were studied to determine possible defects in immunologic function or complement levels. Quantitation of B cells and T-cell subsets revealed slight decreases in the proportions of CD3 and CD4 cells but normal or increased absolute numbers of all cell populations. IgM synthesis in vitro by peripheral blood mononuclear cells was markedly diminished, but IgG synthesis was normal. Fractionation studies, in which various B-cell- and T-cell-enriched populations from controls and patients were combined, demonstrated diminished B-cell function in the patients. Sickle cell patients, who were functionally asplenic, showed similar deficits. Complement levels in splenectomized and sickle cell patients in both the classical and alternative pathways were generally normal. A modest decrease in component H in the alternative pathway in splenectomized and sickle cell patients probably was not clinically significant. In summary, splenectomized patients have a diminished capacity for IgM synthesis that can be attributed primarily to defective B-cell function. This may be partially responsible for their increased susceptibility to infection by encapsulated organisms.

Adolescent↗
PubMed1988

Separation of oligosaccharides containing terminal alpha-linked galactose residues by affinity chromatography on Griffonia simplicifolia I bound to concanavalin A-sepharose.

The seeds of Griffonia simplicifolia contain a family of five isolectins (GS-I) (L. A. Murphy and I. J. Goldstein (1977) J. Biol. Chem. 252, 4739-4742) that bind with high affinity to glycoconjugates containing terminal nonreducing alpha-linked galactose residues. Here, we report that GS-I itself is bound via its high mannose-type, Asn-linked sugar chains to immobilized concanavalin A (Con A-Sepharose). The GS-I in the GS-I-Con A-Sepharose complex retains its ability to bind glycoconjugates containing terminal alpha-linked galactose residues. This convenient method to immobilize GS-I is rapid and quantitative. We have exploited this affinity system to separate oligosaccharides based on their number of terminal alpha-linked D-galactose residues.

Animals↗
PubMed1988

Evans syndrome in childhood: pathophysiology, clinical course, and treatment.

Evans syndrome is defined as the simultaneous or sequential occurrence of Coombs' positive hemolytic anemia and immune thrombocytopenia without known underlying etiology. Ten cases of Evans syndrome were seen at our hospital over the past decade; three patients died. Two cases are described in detail and demonstrate the chronic, refractory nature of this condition. Most patients have required corticosteroid therapy and splenectomy, but further therapy (e.g., intravenous gammaglobulin, danazol, cyclophosphamide) is usually necessary because of recurrent autoimmune hemolytic anemia, thrombocytopenia, or both. There is a substantial risk for development of other autoimmune problems and hypogammaglobulinemia. A number of defects in humoral immunity have been described in Evans syndrome; different antibodies are directed against platelets and red blood cells. Cellular immunity is probably abnormal, but a distinct pattern of immunoregulatory disturbance has not been identified.

Adolescent↗
PubMed1988

Transcutaneous electrical nerve stimulation treatment of sickle cell pain crises.

Transcutaneous electrical nerve stimulation (TENS) has been used in a variety of acute and chronic painful conditions, but has not been studied in sickle cell pain crises. We compared TENS versus placebo in a randomized, double-blind, cross-over study involving 60 trials in 4 crisis severity categories. TENS electrodes were applied to the area of severest pain and patients' pain ratings and medication usage were evaluated over a 4-hour period. Pain ratings and analgesic requirements at 1 and 4 h from onset of study were similar in the TENS and placebo groups. Patients assessments of overall treatment efficacy indicated that TENS was more frequently helpful, but there was a substantial placebo effect. Although the value of TENS in this condition was not established in this study, further trials, using varied stimulation parameters, are warranted.

Acute Disease↗
PubMed1987

A novel sialylfucopentaose in human milk. Presence of this oligosaccharide is not dependent on expression of the secretor or Lewis fucosyltransferases.

We have identified a novel oligosaccharide in human milk that is a fucosyl derivative of sialyltetrasaccharide c (NeuAc alpha 2-6Gal beta 1-4GlcNAc beta 1-3Gal beta 1-4Glc). This oligosaccharide was purified by affinity chromatography on a column of immobilized Ricinus communis I lectin. Structural analyses of radiolabeled oligosaccharides by exoglycosidase digestions, binding by specific anti-carbohydrate antibodies, and analysis of the 3H-labeled glucitol derivative obtained after permethylation and hydrolysis are consistent with the following proposed structure. (formula; see text) The analyses of human milk sialylpentasaccharides from donors typed as Le(a-,b+), Le(a+,b-), and Le(a-,b-) secretor confirmed the secretor gene-dependent expression of the sialylated lacto-N-fucopentaose I (Fuc alpha 1-2Gal beta 1-3[NeuAc alpha 2-6]GlcNAc beta 1-3Gal beta 1-4Glc) and the Lewis gene-dependent expression of the sialylated lacto-N-fucopentaose II (NeuAc alpha 2-3Gal beta 1-3[Fuc alpha 1-4]GlcNAc beta 1-4Glc). However, the presence of this novel oligosaccharide in human milk is not dependent on the expression of either the secretor gene or the Lewis gene-specified fucosyltransferases.

Carbohydrate Sequence↗
PubMed1987

An assay for leukoagglutinating lectins using suspension cultured mouse lymphoma cells (BW5147) stained with neutral red.

A sensitive and rapid assay for leukoagglutinating lectins has been developed. This assay utilizes neutral red-stained mouse lymphoma cells from the suspension cultured cell line BW5147. The agglutination of the stained cells can be monitored visually in a manner similar to that for conventional assays for erythroagglutinating lectins using erythrocytes. The activity of lekoagglutinating lectins that are not capable of agglutinating erythrocytes can be quantified by this assay. The utility of the assay was demonstrated using leukoagglutinating and erythroagglutinating lectins from the seeds of Phaseolus vulgaris and Maackia amurensis.

Animals↗
PubMed1987

Inhibition of somatostatin on glucose-induced release of gastric inhibitory polypeptide in rats.

The effect of somatostatin on glucoseinduced secretion of insulin and gastric inhibitory polypeptide (GIP) in rats was examined. Anesthetized male rats were catheterized via the right carotid artery before gastric infusion of 2 ml of 40% glucose through a syringe pump over 3 min. Ten micrograms somatostatin dissolved in 0.5 ml saline was injected intraperitoneally 10 min before oral glucose administration. Rats receiving 0.5 ml saline were used as controls. Blood samples were collected at -10, 0, 10, 20, 30, 45, 60, and 90 min after glucose infusion. Concentrations of GIP and insulin in rat plasma samples were measured by radioimmunoassay. The level of plasma glucose was determined by YSI glucose analyzer. The results revealed that the rise of plasma insulin and GIP after the glucose load was abolished by a preinjection of somatostatin. It is concluded that somatostatin at 10 micrograms inhibits the effects of oral glucose in stimulating the secretion of GIP from the gut, and insulin from the pancreas in normal fasted rats.

Animals↗
PubMed1986

Bacteremia in sickle hemoglobinopathies.

We analyzed 178 episodes of bacteremia that occurred during 13,771 patient-years of follow-up of 3451 patients with sickle hemoglobinopathies. Age-specific incidence rates of bacteremia were calculated for patients with sickle cell anemia (SS) and sickle cell-hemoglobin C (SC) disease. The incidence rate was highest among children with SS and SC younger than age 2 years. Children with SC showed an abrupt decrease after age 2 years, whereas children with SS had a gradual decline in rate from 2 to 6 years of age. The predominant pathogen in patients younger than 6 years was Streptococcus pneumoniae (66%); gram-negative organisms were responsible for 50% of bacteremias in patients 6 years and older. Urinary tract infection was present during 73% of Escherichia coli bacteremias, and 77% of Salmonella bacteremias were associated with osteomyelitis. In contrast, no focus of infection was present in 52% of pneumococcal bacteremias. The incidence of pneumococcal bacteremia in children with SS younger than age 3 years was 6.1 events/100 patient-years; the case fatality rate for pneumococcal sepsis in this age group was 24%. No hematologic or demographic variables were associated with occurrence of pneumococcal bacteremia in young children. Retrospective analysis of pneumococcal bacteremia suggests that the prophylactic use of penicillin may decrease the incidence in children younger than 3 years of age.

Anemia, Sickle Cell↗
PubMed1986

Non-transferrin-bound iron in long-term transfusion in children with congenital anemias.

Non-transferrin-bound iron (NTBI), a potentially toxic compound, is increased in the serum of patients with iron overload and fully saturated transferrin. We found markedly elevated NTBI levels in 16 children (including nine with sickle cell disease and five with beta-thalassemia) with iron overload secondary to prolonged transfusion therapy. During iron chelation with subcutaneous desferrioxamine infusion, NTBI levels decreased to normal, but became elevated within 2 to 4 hours after discontinuation of desferrioxamine. NTBI causes hepatic and cardiac toxicity in experimental systems, but our patients lacked sufficient organ dysfunction for this association to be made. The use of continuous 24-hour chelation to maintain NTBI at low levels may prevent progressive iron toxicity in patients who first received chelation therapy at an older age or who already have evidence of cardiac damage.

Adolescent↗
PubMed1986

Lymphocyte subsets in children with aplastic anemia.

Twenty-four patients with aplastic anemia (AA) were evaluated with immunologic studies. Patients with posthepatitis AA had decreased proportions of T4 cells, increased proportions of T8 cells, and decreased T4:T8 ratios. Patients with constitutional AA had varied immunologic findings. There were no significant abnormalities in lymphocyte subsets in patients with idiopathic AA. Of the 12 patients who were treated with antithymocyte globulin (ATG), six (50%) responded. Nine of these patients are living 3-27 months after treatment; three of the nine are transfusion dependent. T-cell subsets were not helpful in predicting the response to ATG. Measurements of other immunologic mediators may be more useful with regard to pathophysiology and prognosis in AA.

Adolescent↗
PubMed1986

Comparison of the heat resistance of bacterial lipases and proteases and the effect on ultra-high temperature milk quality.

Thirty-four of 49 isolates of psychrotrophic bacteria produced extracellular lipase or protease when grown in rehydrated nonfat dry milk. The cell-free crude preparation from 50% of these had either heat-resistant lipase or protease; in 30% both enzymes were heat resistant. Eight isolates were selected for further evaluation of effect on ultra-high temperature processed milk. Free fatty acids and free amino groups of milk precultured with the bacteria increased at different rates depending on the isolate. Partially purified lipase from one of these bacteria (Acinetobacter sp.) caused free fatty acids to increase following ultra-high temperature processing when the milk was stored at 10, 21, or 32 degrees C for 4 wk. The increase was temperature dependent. Lipase activity of .0012 units/ml added prior to processing caused significant increases in free fatty acid at 21 and 32 degrees C in 4 wk.

Acinetobacter↗