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Biomedical subjects

J Albert

Publications and source records attributed to J Albert.

At least 253 records · Page 14Linked to original sources
PubMed1981

Inhibin in the human prostate.

"Inhibin"-like protein, partially purified from the human prostate, was similar to that obtained from human seminal plasma under identical conditions. Concentration of inhibin in human prostate was tenfold higher as compared to human testis and was active biologically and immunologically. The presence of a high amount of inhibin in prostate seems to be unique in humans. Further inhibin concentration in benign prostatic hypertrophy tissue increased by tenfold in comparison to normal or cancerous tissue. Hence determination of serum level of inhibin may be used as a therapeutic tool to monitor prostate diseases.

Animals↗
PubMed1980

Processive nature of reverse transcription by avian myeloblastosis virus deoxyribonucleic acid polymerase.

The ribonucleic acid dependent deoxyribonucleic acid polymerase from avian myeloblastosis virus was shown to synthesize poly(dT) transcripts by a processive mechanism using poly(rA)1100.oligo(dT)12-18 as template and primer. Template challenge experiments demonstrate that at low temperature and ionic strength, the polymerase remains bound to the completed template-daughter strand complex after completion of daughter strand elongation. Higher temperatures and ionic strength increase the dissociation of the enzyme from the complex, thus reducing transcript length. Analysis of product size and quantity indicates that the degree of processivity is also influenced by the types and concentrations of metal ions present and indicates that the metal ions affect the activity of the poly(rA) as a template more than they affect processivity or enzyme activity. The results also lead to the conclusion that initiation is the rate-limiting step under all of our experimental conditions. The arguments for a processive as opposed to distributive mechanism are based on an analysis of enzyme-template interactions, product size, and amount of product made under specific reaction conditions.

Avian Leukosis Virus↗
PubMed1980

Codistribution of collagen types IV and AB2 in basement membranes and mesangium of the kidney. an immunoferritin study of ultrathin frozen sections.

Affinity-purified rabbit antibodies specific for collagen types I, III, AB2 and for a partially characterized type IV collagen derived from a murine tumor were used to study the distribution of collagens in the normal mouse kidney. Immunofluorescence staining of conventional frozen sections demonstrated that types I and III were present in bundles around large vessels and in fibers surrounding glomeruli and tubules, whereas types IV and AB2 were distributed in a linear fashion along basement membranes of tubules, glomeruli, and Bowman's capsule and in the mesangial stalk. The distribution of types IV nd AB2 was examined at the ultrastructural level by staining of 600- to 800-A thick frozen sections with a three-stage procedure employing specific collagen antibodies, biotinyl sheep antirabbit IgG, and avidin-ferritin conjugates. Labeling by this procedure demonstrated codistribution of types AB2 and the putative type IV in all three basement membranes. In addition, mesangial matrix was shown to contain both of these collagen types. These results support recent biochemical evidence of collagen heterogeneity in basement membranes, and also support the concept of a structural relationship between mesangial matrix and glomerular basement membranes.

Animals↗
PubMed1980

Plasma levels of 8-methoxypsoralen determined by high-pressure liquid chromatography in psoriatic patients ingesting drug from two manufacturers.

We have adapted a rapid and sensitive high-pressure liquid chromatographic technique (HPLC) to measure plasma levels of 8-methoxypsoralen (8-MOP) in 22 psoriatic patients receiving photochemotherapy with 8-MOP and long-wave ultraviolet light (PUVA). In this procedure, 1 ml plasma samples containing ammidin as an internal standard are extracted with benzene. After evaporation under nitrogen the residue is redissolved in methylenechloride:acetonitrile, 95:5, and chromatographed using a normal phase HPLC system with a 10 mu silica particle column and a UV detector at 254 nm. The sensitivity of the method is 10 ng/ml plasma. Plasma concentrations of 8-MOP were measured between 2 and 4 hr after ingestion of therapeutic doses of 8-MOP provided by 2 manufacturers. Mean 8-MOP plasma levels were 27 +/- 35 ng/ml plasma 2 hr after ingestion of the only drug presently available on the U.S. market, 8-MOP (Elder). These values were significantly below (p less than 0.001) those obtained with 8-MOP (Roche) which were 104 +/- 79 ng/ml plasma. A number of patients on 8-MOP (Elder) did not have detectable levels of 8-MOP 2 hr after ingestion. The time course patterns also differed, possibly indicating a slower and less complete absorption for 8-MOP (Elder). Repeated time course studies in the same patient were reproducible although the absolute concentrations showed some variation. Preliminary evidence indicates that the plasma levels of 8-MOP have therapeutic relevance.

Adolescent↗
PubMed1980

[The oxygen saturation of blood in the venae cavae, right-heart chambers, and pulmonary artery, comparison of formulae to estimate mixed venous blood in healthy infants and children (author's transl)].

For the localization and quantification of arterio-venous shunts of the heart and great vessels, accurate definition of the degree of oxygen saturation of venous blood in the venae cavae, right heart and pulmonary artery is essential. Hitherto only a few investigations in a small number of healthy subjects were published. Extensive investigations to define normal mixed venous blood in infants and children are unknown. This presentation is an analysis of the data on oxygen saturation of venous blood in 305 healthy children or patients with insignificant cardiac defects. Shunt lesions were excluded. A comparison of several formulae used to estimate the oxygen saturation of mixed venous blood from caval samples has been made. The sources of error in the estimation of mixed venous blood and the implications for the calculation of the shunt-volume are investigated in 122 patients without cardiac defects. The mean oxygen saturation from the right ventricle most nearly approached the mean oxygen saturation of the pulmonary artery whereas high inferior vena cava saturations correlated poorly with mixed venous blood. Superior vena cava, the mean oxygen saturation of the right atrium and the formula 3 x SVC + HIVC divided by 4 = MVB (where SVC is superior vena cava, HIVC is high inferior vena cava MVB is and mixed venous blood) gave a satisfactory regression and have nearly the same value for prediction of mixed venous blood.

Adolescent↗
PubMed1978

Dihydrotestosterone concentration in prostate cancer tissue as a predictor of tumor differentiation and hormonal dependency.

Tissue dihydrotestosterone and 5alpha-reductase (delta4-3-ketosteroid-5alpha-oxidoreductase) levels have been measured in prostates of patients with cancer and benign prostatic hypertrophy; significant decreases in average values for both of these biochemical parameters were noted in prostate cancer compared to benign prostatic hypertrophy, although individual values overlapped in both groups. Prostate cancer tissue dihydrotestosterone levels appeared to correlate better than did either histological tumor grading or 5alpha-reductase with the ultimate clinical response to antiandrogen therapy. These results suggest that assay of tissue dihydrotestosterone levels in prostate cancer should be further explored as a possible marker for tumor differentiation.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗