PubMed Health⌕ Search

Biomedical subjects

R M Cohn

Publications and source records attributed to R M Cohn.

15 recordsLinked to original sources
PubMed1980

Evaluation of the binding of serotonin by isolated CNS acidic lipids.

Binding of serotonin by rat lipids was examined in an organic solvent-aqueous partition system. Only phospholipids and sulfatide were found to have appreciable activity; this technique was unsuitable for gangliosides due to their poor extractibility. Binding by phospholipid was abolished and that by sulfatide was greatly inhibited by increasing ionic strength in the aqueous phase. At an ionic strength of 0.3 M the apparent affinity of sulfatide for serotonin was about 3 X 10(3) M. Both tryptamine and 5-methoxytryptamine were much more effective than serotonin in inhibiting the binding of radioactive serotonin, suggesting that the observed binding is simply a charge neutralization with little specificity. Binding of serotonin by mixed brain gangliosides was examined in an equilibrium dialysis system. Without adequate precautions, the chemical lability of serotonin was found to produce spurious data when binding was assessed by the distribution of radiolabel. Binding of serotonin by ganglioside was also greatly inhibited by increasing ionic strength: at 0.3 M an apparent affinity of about 10(3) M was found. While dopamine did not inhibit the binding of radioactive serotonin, tryptamine, 5-methoxytryptamine, and serotonin were equally effective inhibitors.

5-Methoxytryptamine↗
PubMed1980

The pancytopenia of isovaleric acidemia.

Severe pancytopenia developed in two infants with isovaleric acidemia. Previous reports indicate these hematologic abnormalities are a leading cause of death in affected infants. Our findings suggest that the pancytopenia may be due to arrested maturation of hematopoietic precursors. Prompt transfusion of appropriate blood components prevented complications due to the hematologic abnormalities.

Amino Acid Metabolism, Inborn Errors↗
PubMed1979

Light stability of norethindrone and ethinyl estradiol formulation with FD&C colorants.

In general, light-sensitive tablets exhibit discoloration in the surface layer(s) only. A case is discussed where a quantitative interaction between a drug, ethinyl estradiol (in a combination tablet containing norethindrone and ethinyl estradiol), and a dye (FD&C Red No. 3) occurs, and discoloration exists throughout the tablet. The data suggest that accelerated light studies should be carried further than those dictated by predictive periods so that equilibrium levels can be deduced.

Coloring Agents↗
PubMed1979

Age and the satisfactions from work.

This research documents age differences in the relative importance of intrinsic work satisfactions as determinants of the individual's sense of global well-being. Evidence of a decline in the importance of these intrinsic satisfactions for men during the later stages of labor force participation is not an artifact of lower levels of satisfaction. Rather, it appears that toward the end of the period of labor force participation, the satisfactions men derive from work are transferred from the actual experience of work to its consequences. The relevance of the results to early retirement policies is considered. Data used in the analysis come from the 1971 Quality of American Life survey. The national cross-sectional survey allows for comparison of the multivariate structure of life satisfactions among four age groups of labor force participants (i.e., 21-34, 35-44, 45-54, 55-64).

Adult↗
PubMed1978

Evaluation of continuous solvent extraction of organic acids from biological fluids.

We evaluated the efficiency of continuous solvent extraction with ether for the analysis of organic acids by gas chromatography using a representative group of organic acids and urine from several normal children. Variables examined were the time of extraction, volume of sample, and the quantity and chemical class of acid present. In terms of the decreased time required and invariant extraction of acids of pathologic significnace continuous solvent extraction compares favorably with the more time consuming albeit less discriminatory ion-exchange procedure. Continuous solvent extraction appears especially well suited for analysis of short chain aliphatic acids by gas chromatography.

Body Fluids↗
PubMed1978

Glycine therapy in isovaleric acidemia.

The therapeutic efficacy of oral glycine was tested in a 3-year-old girl with isovaleric acidemia. An oral leucine load (25 mg/kg) caused a rise of the blood levels of isovaleric, lactic, and pyruvic acids as well as an increase of urinary excretion of the ketone bodies. These changes did not occur when oral glycine (250 mg/kg) was given with the leucine. Glycine supplementation favored the formation of isovalerylglycine, a nontoxic conjugate of isovaleric acid which is excreted rapidly. Excretion of isovalerylglycine rose threefold when leucine and glycine were administered simultaneously. Chronic glycine therapy was tolerated well and may have prevented one episode of ketoacidosis.

Acidosis↗
PubMed1978

Urinary citrate excretion in the diagnosis of distal renal tubular acidosis.

Since hypocitraturia in distal renal tubular acidosis, we screened the asymptomatic children in three families with familial dRTA, by comparing their 24-hour urine citrate excretion to values obtained in 45 normal children. Subsequent acid loading uncovered four new cases of dRTA suspected because of the finding of hypocitraturia. Because hypocitraturia probably contributes to nephrolithiasis/nephrocalcinosis and subsequent renal damage in dRTA, affected family members were treated with alkali (4 mEq/kg/day), which normalized urine citrate in three children; in a fourth child citrate excretion rose but was not normal. Measurement of urine citrate excretion was superior to other currently proposed screening tests for dRTA (first morning urine pH and sediment, urine concentration).

Acidosis, Renal Tubular↗
PubMed1977

Phenylalanine-tyrosine deficiency syndrome as a complication of the management of hereditary tyrosinemia.

A male infant with type I hereditary tyrosinemia developed a phenylalanine-tyrosine deficiency syndrome after receiving a synthetic diet which was low in these amino acids. The syndrome was characterized by growth failure, anorexia, lethargy, and hypotonia. Hypophenylalaninemia and hypotyrosinemia were discovered. The blood concentration of most other amino acids were increased. Supplementation of the patient's diet with phenylalanine and tyrosine resulted in a prompt and dramatic reversal of both clinical and biochemical abnormalities. Dietary therapy had no effect on the child's hepatic cirrhosis.

Amino Acid Metabolism, Inborn Errors↗
PubMed1977

Relative toxicity and metabolic effects of cholecalciferol and 25-hydroxycholecalciferol in chicks.

The relative toxicity and metabolic effectiveness of cholecalciferol (CC) and 25-hydroxycholecalciferol (25-HCC) in chicks were evaluated by feeding six graded levels of each and observing gross and microscopic pathology as well as several metabolic parameters of calcium metabolism. Renal tubular calcification was observed when CC was fed at the rate of 10.0 mg/kg of diet and when 25-HCC was fed at the rate of 0.1 mg/kg diet. Thus, 100-fold increase in toxicity results when the hydroxylated form of CC is fed. Both microscopic renal lesions and increased renal calcium and inorganic phosphate concentrations occurred in chicks with normal serum calcium concentrations.

Alkaline Phosphatase↗