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Biomedical subjects

L Cohen

Publications and source records attributed to L Cohen.

At least 505 records · Page 28Linked to original sources
PubMed1981

Plasma enzyme determinations in normal and dystrophic mice.

The plasma levels of creatine kinase (CK), lactate dehydrogenase and alkaline phosphatase were determined in normal mice of the white CF1 and black C57Bl/6 strains, and in clinically normal, heterozygous and dystrophic mice of the C57BL/6J-dy strain. CF1 mice, 13-130 days old, had an average plasma CK of 152 +/- 58 mIU/ml (mean +/- standard deviation) (n=19). Mice of the C57BL/6 strain had a CK of 164 +/- 39 mIU/ml (n=5). Dystrophic mice, younger than 80 days, had an average CK of 1186 +/- 609 mIU/ml (n=16). The CK levels in plasma from 3 dystrophic mice (99, 99 and 156 days) were 182, 267 and 169 (mean 206) mIU/ml, respectively. CK activities in known heterozygotes (+/dy), 180-200 days old, were 165 +/- 156 mIU/ml (n=7). Up to 80 days of age, 14 clinically normal littermates of dystrophic mice showed two distinct groupings of CK activity. Four animals had a mean of 1136 +/- 418 mIU/ml, while 10 others had a mean CK of 173 +/- 116 mIU/ml. The reasons for the 4 elevated values have yet to be established. Over 80 days of age, the average CK was 152 +/- 63 mIU/ml (n=5). When compared statistically, only the young (less than 80 days) dystrophic and four clinically normal animals, with elevated CK levels, were significantly different from the other six groups of mice examined (p less than 0.001). The data indicate that the plasma CK level in C57BL/6J-dy dystrophic mice is elevated, at least up to about 11 weeks.

Aging↗
PubMed1981

Biochemical analysis of specific histamine HI and H2 receptors on lymphocytes.

It is increasingly clear that histamine mediates a variety of lymphocyte functions. Further understanding of these mechanisms requires a method for the analysis of histamine membrane receptors on the lymphocyte surface. We report now a biochemical technique for the identification and quantitation of specific histamine H1 and H2 receptors of lymphocytes. The method can be performed on small numbers of formaldehyde-fixed cells. The data this assay yields, together with that resulting from the flow cytometric analysis of histamine receptor distribution (a technique we have previously described), will be a powerful tool in the study of histamine mediation of lymphocyte function.

Histamine↗
PubMed1981

Infrared spectroscopy and magnesium content of bone mineral in osteoporotic women.

Larger and more perfect crystals in bone mineral from osteoporotic women have been described using biophysical methods. In search of the cause of this change, both chemical analysis and infrared spectrophotometry were used on iliac crest bone biopsies from 19 postmenopausal osteoporotic women. These women had each had a vertebral crush fracture and had a urinary hydroxyproline: creatinine ratio greater than 0.012. Lower than normal trabecular bone magnesium content and larger and more perfect crystals in trabecular bone mineral identified on infrared spectrophotometry were found in 16 out of the 19 women. Magnesium deficiency was confirmed by Thoren's magnesium load test in this subgroup of 16. Higher than normal bone magnesium content and smaller and less perfect crystals in bone mineral were found in five postmenopausal uremic women tested.

Aged↗
PubMed1981

Localization of 3H-diethylstilbestrol in skeletal muscle.

The localization of diethylstilbestrol (DES) in skeletal muscle was studied in CF1 mice and perfused rat hindlimbs. There was a slow accumulation of 3H-DES in mouse muscle from 4 to 24 hours following i.p. injection even though plasma DES was decreasing. Twenty-four hours after injection of 50 microCi 3H-DES (714 pmole) mouse gastrocnemius contained 8.9 x 10(-17) mole unaltered 3H-DES per mg muscle. Extrapolating to the entire skeletal muscle mass of the animal, this represents 0.15% of the radioactivity injected. The radioactivity in muscle was completely extracted with 95% ethanol or ether: ethanol (3:1), and both unaltered DES and DES-metabolites were present in the extracts. The fraction of radioactivity due to unaltered DES 4 hours after injection was 0.51 +/- 0.09 in muscle and 0.30 +/- 0.11 in plasma. Significant extrahepatic metabolism of DES was demonstrated in perfused isolated rat hindlimbs by the presence of DES-metabolites in the perfusate. The radioactivity extracted from the perfused muscle itself was unaltered DES. These results indicate that skeletal muscle is an important site of DES localization in rodents.

Animals↗
PubMed1980

Small-cell carcinoma of the lung: a five-year experience with combined modality therapy.

In the past five years, we have treated 89 patients with small-cell carcinoma of the lung with radiotherapy plus one of three chemotherapy programs. The 24 patients with disease confined to the chest (Stage IIIMO) had an 87% response rate to the combined modalities (79% complete responses) and a median survival of 18 months; 13 patients with disease confined to the chest and ipsilateral supraclavicular nodes (Stage IIIMOSCN +) had an 84% response rate (69% complete responses) and 11-month median survival; the 52 patients with distant metastases (Stage IIIMI) had a 71% response rate (15% complete responses) and eight-month median survival. Survival was not affected by adding prophylactic cranial irradiation to the latest regimen, although the CNS relapse rate was reduced. We conclude that our three chemotherapy programs to date differ very little in their effect on survival of patients with metastatic disease. New and more vigorous approaches, possibly including surgery, need to be tested for the management of disease confined to the chest. The designation of patients as Stage IIIMOSCN + is valid because such patients have better survival rates than patients with distant metastatic disease.

Adult↗
PubMed1980

Somatostatin stimulates glucagon secretion in ducks.

In normal fasting ducks, a somatostatin infusion (800 ng/kg/min for 30 min) elicited a prompt inhibition of insulin secretion, plasma levels falling from 140 +/- 20 to 20 +/- 6 pg Eq/ml as observed in mammals.--However plasma glucagon-like-immunoreactivity shown to be decreased in mammals by somatostatin was sharply increased from a mean basal level of 1.46 +/- 0.13 ng Eq/ml to 6.61 +/- 0.77 ng Eq/ml. This effect was not mediated via inhibition of growth hormone secretion since it was also observed in hypophysectomised ducks. Despite the fall in plasma insulin and rise in GLI observed with somatostatin infusion in intact birds, plasma glucose concentrations were lower than with control saline infusion.

Animals↗
PubMed1980

Amino-acid neighborhood relationships in proteins. Breakdown of amino-acid sequences into overlapping doublets, triplets and quadruplets.

A method has been developed which allows the breakdown of an amino-acid sequence of proteins into overlapping di-, tripeptides, etc. The frequency of their distribution provides very convincing evidence that these sequences are non-random. These peptides have been demonstrated to be capable of being used as an objective key for the classification of organisms, and of proteins. It is also believed that they can be useful in increasing the accuracy of the prediction of protein folding.

Amino Acid Sequence↗