Biomedical subjects
Publications and source records attributed to S D Sarkar.
Two cases of unstable hemipelvic fractures with internal rotation displacement successfully treated by outward (external lateral) rotation and continuous skeletal traction by wires passed through the crest of the ilium are described. X-rays show both patients before and 2 years after treatment.
A tissue distribution study with 75Se-19-selenocholesterol in rats, rabbits, and dogs showed high adrenal concentrations and good adrenal images. In the dog, higher concentrations were obtained in the adrenal medulla than in the cortex at Days 1 and 7 after dosing. Extraction and thin-layer chromatography of the adrenal lipid in dogs given this compound showed that 75Se in the adrenal is still attached to the steroid moiety. A reduction in production costs is expected from its longer shelf life. Selenium-75-19-selenocholesterol is being evaluated in humans not only for routine use as a adrenal cortex scanning agent, but also for the detection of pheochromocytomas and other sympathetic tissue tumors, especially neuroblastomas.
Tissue distribution studies were performed in rats and dogs at five time intervals between 10 min and 24 hr after the intravenous injection of one of the following radiolabeled adrenocortical enzyme inhibitors: 3H-amino-glutethimide, 125I-3-iodoaminoglutethimide, 3H-SKF-12185, 125I-3-SKF-12185, 3H-metyrapone. 3H-metyrapol. 3H-amphenone B, and 3H-SU-10603. In rats, 3H-SKF-12185 showed the highest uptake in the whole adrenal (3.5% kg dose/gm at 1 hr). In dogs, 3H-metyrapol showed the highest uptake in the adrenal cortex (9% kg dose/gm at 1 hr), and the peak cortex-to-liver concentration ratio was 57 at 2 hr. These peaks uptakes were comparable to those obtained with the conventional iodocholesterols, but they were reached much earlier, with elimination of most of the adrenal radioactivity by 24 hr. These properties would permit the use of 123I as the label and a higher tracer dose, resulting in a higher photon flux. Thus, the radiolabeled enzyme inhibitors show promise as adrenal-scanning agents, with a markedly shortened scanning procedure, a lower absorbed radiation dose, and better resolution.
Forty patients aged 20 years or less who had been treated with 131I after surgery for papillary-follicular thyroid carcinoma were contacted for followup study. Five had died and two were unmarried; the remaining 33 were studied with respect to their subsequent reproductive histories and the health of the offspring. The mean age at the time of the first 131I therapeutic dose was 14.6 years (range 6-20), and the average followup interval, from that first dose until followup, was 18.7 years (range 14-25). The mean total dose of 131I was 196 mCi (range 80-691). The incidences of infertility (12%), miscarriage (1.4%), prematurity (8%), and major congenital anomaly (1.4%) found in this series are not significantly different from those in the general population. Thus, our study offers no overt evidence of genetic damage in children and adolescents treated with high doses of 131I for thyroid carcinoma.
The first synthesis of 131I-19-iodocholesterol had a 10-25% radiochemical impurity that was not iodide ion. This impurity has been identified as 6beta-131I-iodomethyl-19-nor cholest 5(10)-en-3beta-ol (NP-59) and has been synthesized. Tissue distribution studies with 131I-NP-59 in rats and dogs revealed a higher adrenal uptake and adrenal-to-tissue ratios compared to 131I-19-iodocholesterol, probably less in vivo deiodination, and superior adrenal images. A high uptake was seen in the adrenal medulla in addition to that in the cortex. Iodine-131-NP-59 is being evaluated for the early detection of adrenal-cortical disorders and as a potential scanning agent for detecting structural abnormalities of the adrenal medulla.
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We report five pediatric cases that illustrate the methodologic pitfalls and limitations of diuretic renography in suspected ureteropelvic junction obstruction. False-positive studies may be related to such avoidable flaws in methodology as premature diuretic administration, inadequate diuretic dose, and bladder distension, or to recent pyeloplasty. False-negative results may occur despite optimum technique, necessitating a follow-up study for confirmation.