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Biomedical subjects

B Wu

Publications and source records attributed to B Wu.

At least 343 records · Page 19Linked to original sources
PubMed1983

Serologic diagnosis of nasopharyngeal carcinoma. A double-blind study of four EB virus antibodies with evaluation by sequential discrimination.

It is generally known that a close relationship exists between Epstein-Barr Virus (EBV) and nasopharyngeal carcinoma (NPC). Recently, patients with early lesions of NPC have been detected in the general population by use of serologic mass survey. Using the double-blind method, we have studied the diagnostic value of the four EBV antibody titers, VCA-IgA, VCA-IgG, EA-IgA and EA-IgG, in four groups of subjects, each consisting of 50 persons: patients with nasopharyngeal carcinoma (NPC group), patients with cancers other than NPC in the head and neck regions (HNC group), patients with cancers outside of head and neck regions (OC group) and normal individuals (NS group). The results of these four antibodies were evaluated both singularly and together by multivariate sequential discrimination. Taking 1:10 as the criterion of being positive, in the NPC group, the positive rate of VCA-IgA is 88%, the VCA-IgG rate is 100%, the EA-IgA rate is 48% and the EA-IgG rate is 74%. In the non-NPC group, the positive rates of VCA-IgA are as high as 86%-92%, but those of the other antibodies are as low as 0-42%. The positive rates and the geometric mean titers of these four antibodies were all elevated as compared with those in the three non-NPC groups. These differences are statistically significant. VCA-IgG is unimportant in the diagnosis of NPC because of its low specificity. By treating the antibody titers of VCA-IgA, VCA-IgG, EA-IgA and EA-IgG with sequential discrimination, the correlation rate between the serology and pathology of NPC is 88% and the false positive rate is 7.3%.

Adolescent↗
PubMed1982

Inhibition of PM-2 DNA degradation by a human serum protein.

A unique DNA-binding protein was detected that inhibited DNA degradation induced by bleomycin and was decreased in sera of cancer patients. The protein from normal human serum was purified to homogeneity by ammonium sulfate precipitation and DEAE-cellulose and DNA-cellulose column chromatography. Two-dimensional isoelectric focusing gel electrophoresis revealed a single protein spot with a molecular weight of 64,000 and a pI at pH 5.9. The NH2 terminus was lysine, and the ratio of acidic to basic residues was 1.2. DNA binding was demonstrated by column chromatography, agarose gel electrophoresis, fluorescence quenching, and circular dichroism. The inhibitory activity was abolished by treatment with Pronase but not by RNase or DNase I. FeCl2 caused a partial loss of inhibitory activity. The inhibition of DNA degradation was more effective for breakage induced by bleomycin than neocarzinostatin, macromomycin, or DNase I. Evidence from DNA-binding studies suggests the inhibition is due to binding of the protein to sites on DNA preferred by bleomycin. Thus, the protein could be useful for studies on the mechanism of action of bleomycin and other antitumor agents, the cytotoxic effects of which are due primarily to damage of cellular DNA. The protein was decreased significantly in sera of cancer patients, and its potential use as a diagnostic tool for neoplasias is being investigated further.

Bleomycin↗
PubMed1976

Detergent lysis for isolation of intact polysomes of Nivikoff hepatoma ascites cells.

An efficient, rapid procedure for the isolation of polysomes from Novikoff hepatoma ascites cells that avoids mechanical shear was developed, and Ivory was used as the detergent to lyse the cells. This method yields classes of large polysomes and 3- to 5-fold increased yields over that of routine homogenization procedures. Up to 70% of the polysome population is larger than tetramers. The polysomes and ribosomes are morphologically intact and contain undegraded ribosomal RNA and biologically active messenger RNA. This procedure also yields nuclei free of cytoplasmic contamination as a by-product of polysome isolation. These nuclei do not show evidence of protein degradation and are enzymatically active with respect to RNA polymerases I and II.

Animals↗
PubMed1975

Characterization of nuclear and chromatin poly A-containing RNA.

Poly A-containing RNA was isolated from Novikoff hepatoma cell chromatin on nitrocellulose membrane filters after the cells were labeled with 32P-orthophosphate for 6 hours. Under denaturing conditions, the poly A-containing chromatin RNA had a sedimentation coefficient of approximately 8-18S. The presence of poly A tracts in the chromatin RNA fractions indicate that poly A addition occurs almost immediately after transcription. Poly A-containing chromatin RNA and nuclear RNA were approximately 1/5 as active as cytoplasmic poly A-containing RNA in the wheat germ translational system. Since chromatin poly A-containing RNA is the precursor of cytoplasmic poly A-containing RNA, further processing of this RNA prior to its attachment to polysomes may account for its increase in translational capacity.

Animals↗
PubMedDate not supplied

Effects of anti-peptide antibodies against the second extracellular loop of human M2 muscarinic acetylcholine receptors on transmembrane potentials and currents in guinea pig ventricular myocytes.

The effects of anti-peptide antibodies against the second extracellular loop of human M2 muscarinic receptor on transmembrane potentials and currents in guinea pig single ventricular cells were analyzed using whole-cell patch clamp technique. These effects were compared with those of the muscarinic receptor agonists carbachol and acetylcholine. The antibodies shortened the action potential duration in a dose-dependent manner. By using a ramp or step rectangular pulse protocol, it was found that the antibodies increased the outward K+ current and decreased the inward basal ICa significantly. The reversal potential of both carbachol- and antibody-induced extra currents were close to -80 mV, being in proximity to the calculated Ek of -90 mV. A beta-adrenergic receptor agonist, isoprenaline, prolonged the action potential and increased the overshoot which could be inhibited by both antibody and carbachol. Isoprenaline increased inward ICa and outward Ik simultaneously. Both antibody and carbachol could significantly reduce the isoprenaline-stimulated ICa but not the isoprenaline-stimulated Ik. The antibody- or carbachol-induced outward K+ current and the depressant effects of antibody and carbachol on isoprenaline-stimulated ICa were partially antagonized by atropine. These results suggest that the anti-M2 muscarinic receptor antibodies display a stimulatory activity similar to muscarinic receptor agonist on the receptor-mediated electrophysiological events.

Acetylcholine↗