Search PubMed⌕ Search

Biomedical subjects

L Shenkman

Publications and source records attributed to L Shenkman.

At least 109 records · Page 6Linked to original sources
PubMedDate not supplied

Selective influence of rat genotype on age-related regional changes in forebrain muscarinic binding.

Muscarinic binding was analyzed in the hippocampus and frontal cerebral cortex of 3 (young) and 24-month-old (aged) inbred Wistar-Kyoto (WKY), Brown-Norway (BN) and Lewis rats, by the specific binding of the antagonist quinuclidinylbenzilate (QNB). While no age-related changes were detected in the hippocampus of all strains, complex changes were found in the cortex. Maximal binding capacity (Bmax) of [3H]QNB was decreased in the cortex of aged WKY rats, remained unchanged in the BN strain and was elevated in Lewis rats. We conclude that regional differences exist in age-related changes in forebrain muscarinic binding which are probably due to differences in the types and connections of cholinoceptive neurons in these regions. The results suggest that it is the rate of these changes which is affected by the rat genotype.

Aging↗
PubMedDate not supplied

The autonomous nodule of the thyroid: correlation of patient age, nodule size and functional status.

In light of new techniques for measuring circulating thyroid hormones and for studying the thyroid gland, we present our experience with 35 patients with solitary autonomous nodules of the thyroid to define more precisely the clinical course of patients with this disorder. The patients ranged in age from 19 to 80 years and 31 of the 35 were female. Younger patients were generally euthyroid and sought attention because of a thyroid mass; virtually all older patients were hyperthyroid. Eighteen had obvious clinical features of hyperthyroidism and 5 over age 70 had apathetic hyperthyroidism; all 5 of the elderly and 13 of the 18 under age 70 had elevated thyroxine (T4) and triiodothyronine (T3) levels. Isolated elevation of T3 and elevated basal metabolic rate were observed in 5 previously untreated clinically hyperthyroid young patients. In each of these, thyroid uptake of 131-I was not suppressible with exogenous T3 and BMR was elevated in those tested. Two elderly patients, who had previously been treated for conventional hyperthyroidism with radioactive iodine, had T3 toxicosis when hypoethyroidism recurred. There was a strong positive correlation between the age of the patient, the size of the nodule and the thyroid functional state. The mean area of the nodules projected on 131-I rectilinear scan for euthyroid patients was 5.1 cm2. The mean area of the nodules in hyperthryoid subjects was significantly higher, 13.4 cm-2 in patients with T3 toxicosis and 19.3 cm-2 in subjects with conventional hyperthyroidism. Progression from a euthyroid state to hyperthyroidism was observed four patients. One of these became thyrotoxic within days after an injection of iodinated contrast medium. Spontaneous resolution of nodules occurred in two patients.

Adenoma↗