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Biomedical subjects

S Lerman

Publications and source records attributed to S Lerman.

At least 91 records · Page 5Linked to original sources
PubMed1978

Inhibition of parathyroid hormone secretion by 25-hydroxycholecalciferol and 24,25-dihydroxycholecalciferol in the dog.

We studied the effects of vitamin D metabolites on parathyroid hormone (PTH) secretion. Test materials were injected into the cranial thyroid artery of the dog, and immunoreactive PTH was measured frequently in serum samples from the inferior thyroid vein and the femoral vein. This model for the study of secretion had previously been validated with the use of known modulators on PTH secretion. In control experiments, injection of 100% ethanol, the vehicle in which cholecalciferol (D(3)) metabolites were suspended, resulted in no change in PTH secretion. Likewise, native vitamin D(3), in doses ranging from 250 to 1,250 ng had no effect on PTH secretion. 25-Hydroxycholecalciferol, 25-(OH)D(3), in doses of 125-240 ng, caused complete suppression of PTH secretion. When 24,25-dihydroxycholecalciferol, 24,25-(OH)(2)D(3), was injected in doses of 50-250 ng, suppression of PTH secretion was again complete; in doses of 5 ng, injection of this metabolite resulted in significant but incomplete suppression of secretion. In doses of 50-250 ng, 1,25-(OH)(2)D(3) strongly stimulated PTH secretion, but in a dose of 5 ng this metabolite had no effects. Injection of equal doses of 1,25-(OH)(2)D(3) and 24,25-(OH)(2)D(3) resulted in significant suppression of PTH secretion. Hypocalcemia-induced stimulation of PTH secretion was suppressed by 24,25-(OH)(2)D(3) while hypercalcemia-induced suppression of PTH secretion was stimulated by 1,25-(OH)(2)D(3). In all experiments showing suppression of PTH secretion, peripheral PTH decreased. Arguments are presented for considering the suppressive effects of D(3) metabolites as physiologic modulators. However, this stimulating effect of 1,25-(OH)(2)D(3) occurred only in pharmacologic doses and hence probably has no physiologic relevance.

Animals↗
PubMed1977

A method for detecting 8-methoxypsoralen in the ocular lens.

The use of 8-methoxypsoralen for treating psoriasis could prove hazardous if this photosensitizing agent enters the ocular lens. Phosphorescence spectra of intact rat lenses reveal concentrations of 8-methoxypsoralen on the order 10(-5)M after intraperitoneal injection of 8-methoxypsoralen. There is evidence that this drug can function as a photosensitizing agent, enhancing ultraviolet-induced changes within the lens.

Animals↗
PubMed1977

Parathyroid hormone and the hypercalcemia of immobilization.

Serial measurements of serum calcium and immunoreactive parathyroid hormone (PTH) were performed in two young patients with hypercalcemia of immobilization. Serum PTH was elevated in both patients. With mobilization, both serum PTH and serum calcium returned to normal levels and remained so during six months of follow-up. The hyperparathyroidism of immobilization is an unexplained, reversible disorder that should be treated by medical measures and aggresive attempts at early mobilization.

Adolescent↗
PubMed1977

Photosensitization of the lens by 8-methoxypsoralen.

During the past decade, ambient ultraviolet radiation has been implicated in the age-related increase in fluorescence and pigmentation of the human lens nucleus. 8-Methoxypsoralen (8-MOP) (currently in vogue for the treatment of psoriasis) is a well-known photosensitizing agent. This drug lar fluorescence (360/440 nm.) and a change in receiving a single intraperitoneal dose (4 to 8 mg./kg.) of 8-MOP. When such rats are subjected to ambient light or ultraviolet (UV) radiation in vivo, there is an enhancement of lenticular fluorescence (360/440 nm.) and a change in their phosphorescence spectra. In vitro studies on lenses derived from rats given 8-MOP and exposed to monochromatic UV radiation show effects similar to those of the in vivo experiments. The foregoing studies demonstrate that 8-methoxypsoralen enters the lens and can be affected by ambient light as well as UV radiation, resulting in a photosensitized enhancement of lenticular fluorescence and a binding of this photosensitizing agent to macromolecules within the lens.

Animals↗
PubMed1975

Hydrophobic chromatography of hepatitis B surface antigen on 1,9-diaminononane or 1,10-diaminodecane linked to agarose.

A series of omega-aminoalkyl-agarose differing in the number of carbon atoms in the alkyl chains was prepared and used for chromatography of hepatitis B surface antigen (HBSAg). HBSAg was separated from the major part of serum proteins by adsorption to columns of 1,9-diaminononane or 1,10-diaminodecane linked to agarose beads (Sepharose 4B or 2B) followed by elution with 4 M-NaSCN.

Alkanes↗
PubMed1975

Perinatal primate parathyroid hormone metabolism.

Near-term fetal and neonatal parathyroid gland function has been studied in the Rhesus monkey. Fetal serum ionized calcium (Ca++) levels are significantly greater than simultaneously obtained maternal levels. Fetal serum parathyroid hormone (PTH) was undetectable both in the basal state and in association with EDTA-induced fetal hypocalcemia. Induced maternal hypocalcemia was associated with increased maternal serum PTH levels and no change in fetal basal serum Ca++ or PTH levels. Only a minimal decrease in simian neonatal serum Ca++ occurred over the first 48 h of life. Normal adult levels of serum PTH were present as early as 6 h of neonatal life. Induced hypocalcemia at 12 h of age resulted in a significant increase in serum PTH levels.

Animals↗