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Biomedical subjects

J S Rodman

Publications and source records attributed to J S Rodman.

47 records · Page 3Linked to original sources

Methyldopa Hepatitis. A report of six cases and review of the literature.

Six cases of methyldopa hepatitis, including two in which the patients died are reported; and 77 cases from the literature are reviewed. Patients in whom severe hepatotoxic reactions to methyldopa develop usually complain of prodromal symptoms typical of hepatitis, often with fever, one to four weeks after therapy is initiated. Jaundice, when it occurs, is usually manifest within three months. Asymptomatic, transient elevations of serum transaminase levels may occur in patients receiving methyldopa. However, since the clinical and histologic features of hepatic injury from methyldopa are indistinguishable from viral hepatitis, it is suggested that the incidence of this iatrogenic disease is higher than generally appreciated. Serum transaminase levels should be determined at the initiation of therapy with methyldopa and four weeks later. Moreover, any patient who has unexplained fever or the prodromal symptoms of hepatitis should undergo liver chemistry studies immediately.

Adrenal Cortex Hormones↗

Evidence for specific recognition sites mediating clearance of lysosomal enzymes in vivo.

A study of the clearance of liver lysosomal enzymes was carried out in the rat. Purified rat liver lysosomal beta-D-glucuronidase (EC 3.2.1.31), N-acetyl-beta-D-glucosaminidase (EC 3.2.1.30), alpha-L-fucosidase (EC 3.2.1.51), and alpha-D-mannosidase (EC 3.2.1.24), as well as rat preputial gland beta-glucuronidase, were infused intravenously into anesthetized rats. All of the enzymes were rapidly cleared from the circulation. Sodium periodate oxidation of lysosomal beta-glucuronidase resulted in a near abolition of rapid clearance, a reduction in concanavilin-A-Sepharose binding, and a reduction in neutral sugar content, accompanied by alteration in isoelectric focusing properties. Similarly, periodate oxidation of lysosomal N-acetyl-beta-D-glucosaminidase resulted in a loss of the rapid clearance property. These results suggest that specific recognition sites occur on lysosomal hydrolases which mediate clearance following intravenous injection, and that these sites involve the carbohydrate portions of the enzymes.

Acetylglucosaminidase↗

Evidence for a precursor to circulating parathyroid hormone.

Bovine parathyroid glands incubated in organ culture synthesize and secrete parathyroid hormone in response to physiologic alterations in cation concentration. Hormone synthesized in the glands is immunologically different and higher in molecular weight than that released into the culture medium or circulating in bovine blood, although it is identical to purified hormone extracted from the glands. On the basis of the physiologic responses of tissue and medium hormone to cation, the transfer of radioactive label from one moiety to another, and interconversion of the two forms by a gland homogenate, it is suggested that the parathyroid glands synthesize a precursor hormone (proparathormone) that is modified to the smaller molecule that circulates in blood.

Animals↗

Parathyroid hormone and the regulation of acid-base balance.

Parathormone (PTH) excess limits renal bicarbonate reabsorption. This may aggravate the acidosis in patients with renal insufficiency and secondary hyperparathyroidism. Why parathormone, the primary action of which is thought to be stabilization of the inonized fraction of calcium, affects acid-base balance remains uncertain. Parathormone not only promotes the release of calcium from bone but also mobilizes salts, including bicarbonate and phosphate. Accumulation of these anions in the extracellular fluid would limit the ionization of calcium. Teleologically it is not unexpected to find that, coincident with evolution of a mechanism which permits rapid mobilization of calcium from bone, a system had to develop which removed the byproducts of bone dissolution. If this concept is valid, parathormone-induced depression of renal bicarbonate reabsorption in uremia represents an undesired side effect of an adaptive mechanism. This would extend Bricker's "trade-off" hypothesis which ascribes metabolic bone disease due to PTH-induced phosphate loss to include metabolic acidosis resulting from diminished renal bicarbonate regeneration. Parathyroidectomy or phosphate restriction have been proposed for correction of the side effects of secondary hyperparathyroidism. These therapeutic manipulations cannot be recommended for general use. A more rational apprach for prevention of secondary hyperparathyroidism is the combined use of phosphate restriction with a short-acting vitamin D derivative.

Acid-Base Equilibrium↗

Using nurse hot line calls for disease surveillance.

Nurse hot line calls are a potential source of public health surveillance data and may help identify epidemics of emerging infectious diseases. In this study, nurse hot line data from Milwaukee, Wisconsin, showed more than a 17-fold increase in calls for diarrhea during the 1993 Milwaukee cryptosporidiosis outbreak. Moreover, consistent patterns of seasonal variation in diarrhea- and vomiting-related calls were detected from the Baltimore, Maryland, and Albuquerque, New Mexico, hot lines. Analysis of nurse hot line calls may provide an inexpensive and timely method for improving disease surveillance.

Cryptosporidiosis↗