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Biomedical subjects

H C Chang

Publications and source records attributed to H C Chang.

At least 235 records · Page 13Linked to original sources
PubMed1980

Neural origin of cells in amniotic fluid.

Cells from the amniotic fluid of fetuses with open neural tube defects (NTDs) have several abnormal characteristics of potential diagnostic value. The cell number in a unit volume of fluid is 10 to 100 times the normal range of cell count. The majority of cells adhere to tissue culture dishes within 24 hours of inoculation, instead of the 4 or 5 days required by normal amniotic fluid cells. The rapidly adhering cells morphologically resemble glial cells. Their Coulter volume is about twice the average seen in normal amniotic fluid--derived cells. This larger number of oversized, rapidly adhering cells is likely due to the continuous accumulation of neural cells in the amniotic fluid. We have detected the presence of the glial protein S-100 and the absence of the neuronal protein 14-3-2 by using a specific immunofluorescence assay. We conclude that fetuses with NTDs shed large numbers of glialike cells into the amniotic fluid where their detection may have diagnostic importance.

Amniotic Fluid↗
PubMed1979

Purification and some physicochemical properties of staphylococcal enterotoxin D.

A method was developed for the isolation of staphylococcal enterotoxin D in highly purified form from cultures of Staphylococcus aureus strain 1151m. The method involves removal of the toxin from the culture supernatant fluid with the ion-exchange resin CG-50 followed by chromatography on carboxymethylcellulose (twice) and by gel filtration on Sephadex G-75 (twice). The purified toxin is homogeneous by polyacrylamide gel and sodium dodecyl sulfate-polyacrylamide gel electrophoresis and double gel diffusion tests. It is a simple, colorless, antigenic protein with an isoelectric point of 7.4 as determined by isoelectric focusing. Its molecular weight was determined to be 27 300 +/- 700 by molecular sieve chromatography on Sephadex G-100 and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Its serological activity is stable over a wide range of pH values (1.2--10.7). The enterotoxin consists of 236 amino acid residues and contains no free sulfhydryl groups. End-group analysis showed serine to be the NH2-terminal amino acid and lysine to be the COOH-terminal amino acid.

Amino Acids↗
PubMed1977

Prognosis of clinically undiagnosed prostatic carcinoma and the influence of endocrine therapy.

A 10-year series of 100 patients with clinically undiagnosed prostatic adenocarcinoma is presented. In 50 per cent of these patients the tumor was well differentiated and the survival was normal, while the remainder of the patients had moderately to poorly differentiated tumors and survival rates significantly less than normal. Of 8 deaths caused by cancer 7 were associated with less-than-well differentiated tumor. Patients who received endocrine therapy and died of causes other than cancer had a significantly shorter interval to death and a higher incidence of cardiovascular deaths than those who were untreated. While the majority of patients with incidental, clinically undiagnosed prostatic carcinoma is not at risk from the disease a minority exists who may benefit from radical therapy.

Adenocarcinoma↗
PubMed1975

Enzymatic and non-enzymatic reduction of nitrite by extracts of Neurospora crassa.

Two activites causing nitrite disappearance are found in extracts of Neurospora; one, inducible by nitrate or nitrite and present only in nitrite-utilizing strains, catalyze the stoichiometric reduction of nitrite to ammonia; the other, present in all strains under all conditions, causes the disappearance of nitrite to something other than ammonia. The latter activity has a molecular weight of about 600 and may contain an oligopeptide, a metal, and an SH group(s). It has no known physiological function.

Ammonia↗