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Biomedical subjects

J Kanabus

Publications and source records attributed to J Kanabus.

8 recordsLinked to original sources
PubMed1987

Extraction of starch by dimethyl sulfoxide and quantitation by enzymatic assay.

A method for the rapid, sensitive, and specific determination of starch in plant tissues is described. Starch from a variety of plant tissues is solubilized by stirring for 24 h or by sonication for 40 min in dimethyl sulfoxide. Dilution of this extract to less than 20% dimethyl sulfoxide permits a nearly complete hydrolysis of the starch in less than 3 h with glucoamylase from Rhizopus niveus. Quantitation of liberated glucose by a coupled hexokinase and glucose-6-phosphate dehydrogenase method provides an additional degree of specificity.

Amylopectin↗
PubMed1978

Properties of human chorionic gonadotropin produced in vitro by ovarian carcinoma cells.

The present study was designed to compare the immunological, physical, and biological properties of native hCG with an hCG molecule secreted ectopically in vitro by an ovarian adenocarcinoma cell line maintained in long term tissue culture. The hCG produced by the cell line was concentrated by ultrafiltration of the tissue culture medium. The inhibition curves generated by serial dilutions of the culture medium concentrates were parallel to those obtained with purified urinary hCG in the beta-hCG RIA and the rat Leydig cell radioreceptor assay (RRA). The ectopic hCG also reacted with an antibody generated against the carboxyl-terminal peptide (109-145) of beta-hCG. The immunoreactive material cochromatographed with urinary hCG on a Sephadex G-100 column, as determined by the beta-hCG RIA and RRA. Neither free alpha nor free beta subunits were found in the tissue culture medium. The tissue culture gonadotropin was adsorbed onto a Concanavalin A-Sepharose column and could be eluted with alpha-D-methylglucoside. The biological activity of the ectopic hCG was 9289 IU/mg, as determined by the ventral prostate weight (VPW) method in hypophysectomized immature male rats. The biological to immunological ratios by the ventral prostate weight method and RRA were 1.79 and 2.17, respectively. The in vivo disappearance rate of ectopic hCG after injection into immature female rats was significantly faster than that of placental or urinary hCG, but was considerably slower than the disappearance rate of human LH. These studies demonstrate that the immunoreactive and biologically active portions of the hCG produced by the ovarian adenocarcinoma cell line and native hCG are similar or identical. The faster disappearance rate of the ectopic hCG in the rat model may be due to incomplete sialylation of the oligosaccharide moiety of the hCG molecule.

Animals↗
PubMed1978

Kinetics of growth and ectopic production of human chorionic gonadotropin by an ovarian cystadenocarcinoma cell line maintained in vitro.

An established ovarian papillary cystadenocarcinoma cell line, designated 163, released immunoreactive human chorionic gonadotropin (HCG) in vitro into the culture medium. The maximal rate of this ectopic activity (10 to 15 ng/day/10(6) cells) occurred at the onset of the logarithmic phase of cell growth and greatly exceeded the intracellular HCG content of cells approaching confluency (0.037 ng/10(6) cells). The HCG production was not detected during the plateau phase of growth. The rate of cellular proliferation and HCG release depended upon the frequency of media change in a manner suggesting that the two processes are interrelated and may be affected by such environmental factors as cell density, nutrient availability, and the accumulation of waste products. The addition of purified HCG to the cultures had no appreciable effect on either the cell growth or the accumulation of HCG. The release of HCG into the medium was greatly stimulated in the presence of sodium butyrate at concentrations from 1 to 10 mM, despite the fact that these concentrations of butyrate resulted in a marked decrease in the cell number/culture in comparison with control media. Equivalent amounts of sodium acetate had no effect on either cell growth or the release of HCG.

Butyrates↗
PubMed1971

Isolation of an organ-specific leucyl-tRNA synthetase from soybean seedling.

The leucyl-tRNA synthetase activity from cotyledons of 4-day-old soybean seedlings has been fractionated into three components. One of these exclusively acylates two of the six tRNA(Leu) species present in this tissue. The remaining two enzyme fractions charge the other four tRNA(Leu) species equally well. Soybean hypocotyls appear to contain only the last two enzyme fractions.

Chromatography↗