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Biomedical subjects

U Weinberg

Publications and source records attributed to U Weinberg.

16 recordsLinked to original sources
PubMed1992

Identification and preliminary characterization of two human digitalis-like substances that are structurally related to digoxin and ouabain.

In order to characterize the structure of endogenous digitalis-like immunoreactive factor (DLIF), we utilized peritoneal dialysis fluid from patients with chronic renal failure as a source of endogenous digitalis-like immunoreactive factor (DLIF), and subjected it to one-step ion exchange chromatography, followed by one step reverse HPLC. Crude dialysis fluid contained 0.09 ng/ml of DLIF, and using Amberlite XAD-2 chromatography we extracted 110 ng of DLIF from 800 ml of dialysis fluid. By applying this partially purified DLIF to our HPLC system, we discerned three peaks of DLIF activity, with retention times of 34, 58 and 63 minutes. The first peak overlapped the elution profile of ouabain, and the third peak co-eluted precisely with digoxin. The second DLIF peak was not in proximity to any of the digitalis-like markers employed. Thus, our results indicate that DLIF isolated from peritoneal dialysis fluid exists in three distinct forms, one of which resembles ouabain, and one which is identical to digoxin.

Digoxin↗
PubMed1979

Circulating melatonin in man: episodic secretion throughout the light-dark cycle.

A sensitive and specific RIA for melatonin has been validated for human plasma. Five young adult men had plasma samples obtained every 20 min during two 24-h periods. One was a normal active period and the other a basal period with complete bed rest. Melatonin was found to be secreted episodically throughout the 24 h in each condition, with secretory episodes clearly present during the waking day in the presence of bright light.

Adult↗
PubMed1978

Studies of the 24 hour rhythm of melatonin in man.

In a series of four separate studies of the 24-hour pattern of melatonin secretory function in man, the following results were obtained. Sequential measurement of the concentration of melatonin in plasma and urine demonstrated a 24-hour rhythm in which more melatonin is secreted during the sleep-lights off as compared to the waking-lights on period. However, during "free-running" and after an acute phase shift of the sleep-wake cycle, a melatonin rhythm can be dissociated from the sleep-lights out rhythm. A radioimmunoassayable plasma melatonin substance was found in significant amounts throughout the entire 24-hour day using a frequent sampling technique (every 20 min). Melatonin appears to be secreted into the blood in discrete brief episodes superimposed on a maintained "baseline" concentration. The half-life appears to be less than 30 min.

Adult↗
PubMedDate not supplied

Coexistence of primary endocrine deficiencies: a unique case of male hypergonadism associated with hypoparathyroidism, hypoadrenocorticism, and hypothyroidism.

The unique combination of male hypogonadism with hypoparathyroidism, hypoadrenalism, hypothyroidism, diabetes mellitus, and alopecia totalis has been documented in a male patient who has been followed over the past 28 years. In this patient, first seen at the age of six for hypoparathyroidism alone, repeated clinical and laboratory endocrine evaluation detected the sequential development of the additional endocrine deficiencies. The presence of abnormal serum antibodies is consistent with an atuoimmune pathogenesis of this syndrome.

Adrenal Insufficiency↗