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Biomedical subjects

J Shull

Publications and source records attributed to J Shull.

4 recordsLinked to original sources
PubMed1989

Absorbable versus permanent mesh in abdominal operations.

Because previous studies evaluating prosthetic mesh have yielded conflicting results, we compared two permanent (polypropylene and polytetrafluoroethylene) and two absorbable (polyglactin and polyglycolic acid) meshes with respect to histologic appearance, development of adhesions, tensile strength and occurrence of hernias in rabbits in which defects of the abdominal wall measuring 2 by 3 centimeters were repaired with one of the meshes. Twenty experiments were performed with each material, and observations were made at two, five, seven and ten weeks. The inflammatory response was minimal with all products. Adhesions were more marked with polypropylene (Marlex) than with polytetrafluoroethylene (Gore-tex); there was no difference between the absorbable meshes. In vitro tensile strength measurements at ten weeks indicated that Marlex was superior to the other materials, and between the absorbable products, polyglactin (Vicryl) was superior to polyglycolic acid (Dexon). No hernias were observed with the nonabsorbable meshes, but all of the rabbits repaired with absorbable meshes had ventral hernias by the tenth week. Thus, absorbable meshes are not indicated when prolonged tensile strength is required, but they may be useful for other purposes, including the temporary repair of fascial defects, since evisceration was not observed.

Abdominal Muscles↗
PubMed1984

Adaptation of the mineralocorticoid target tissues to the high circulating cortisol and progesterone plasma levels in the squirrel monkey.

Many New World primate species have elevated circulating free plasma cortisol concentrations, target tissue resistance to cortisol, and no evidence of sodium retention. A representative New World primate, the squirrel monkey (Saimiri sciureus), has plasma cortisol concentrations above those necessary to cause complete suppression of the renin-angiotensin-aldosterone axis in an Old World primate, the cynomolgus monkey (Macaca fascicularis). Despite this, the arterial blood pressure as well as the plasma sodium, potassium, and bicarbonate levels of the squirrel monkey are similar to those of the cynomolgus monkey, and its plasma aldosterone concentrations are approximately 2-fold higher. These findings suggest that cortisol has minimal sodium-retaining effects in this species. Renal cytosol aldosterone receptor concentrations are about 2- to 3-fold lower in the squirrel monkey than in the cynomolgus, whereas the receptor affinities for [3H]aldosterone are similar in the two monkeys. Higher concentrations of cortisol are needed to displace [3H]aldosterone from the mineralocorticoid receptor in the squirrel monkey than from the renal receptor in the cynomolgus [apparent equilibrium dissociation constant (Ki) = 7.8 X 10(-7) vs. 2.9 X 10(-8) M, respectively]. In addition, in contrast to man and presumably other Old World primates, plasma aldosterone concentrations in the female squirrel monkey do not increase during the reproductive cycle or pregnancy when progesterone concentrations are 10- to 20-fold higher than those of the male or the reproductively quiescent female. This suggests that progesterone is a poor aldosterone antagonist in this species. We conclude that a low concentration of mineralocorticoid receptors in New World Primates is compensated for by higher aldosterone levels, with a concomitant increase in receptor occupancy. The salt-retaining potency of cortisol is low, presumably because of a decrease in the affinity of the aldosterone receptor for glucocorticoids in New World primates.

Adrenal Cortex Hormones↗
PubMed1983

Persistent hyperparathyroidism caused by incomplete parathyroid resection and a hyperfunctioning parathyroid autograft.

A case of familial primary hyperparathyroidism occurred in which persistent hypercalcemia was caused by hyperplastic parathyroid tissue left in the neck and mediastinum after initial surgery and by a hyperfunctioning parathyroid autograft in the forearm. Successful therapy required parathyroid localization and resection of tissue from the neck, mediastinum, and forearm. Parathyroid tissue should be autotransplanted at the time of initial surgery only when total parathyroidectomy is judged likely to have been achieved.

Adult↗