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Biomedical subjects

R D Ice

Publications and source records attributed to R D Ice.

At least 37 records · Page 2Linked to original sources

Generator-produced 99m TcO4-: carrier free.

A solution of 99m-TCO4-minus, as eluted from a 99Mo-99mTc radionuclide generator contains a greater chemical quantity of technetium than that attributable to the metastable isomer alone. The isomeric transition of the radionuclide of interest, 99mTc, gives rise to a determinable and chemically significant quantity of technetium carrier, 99Tc. A method is presented for calculating the total chemical quantity of technetium in a generator eluate.

Molybdenum↗

Myocardial uptake of labeled oleic and linoleic acids.

Oleic acid labeled with 14C, (14C-OA) or 131I (131I-OA) and 131I-labeled linoleic acid (131I-LOA) were administered intravenously to rats and tissue distribution studies completed at various time intervals from 5 to 60 min. Tissue distribution of 131-I-labeled oleic acid or linoleic acid was also studied in dogs at 5- and 30-min time intervals after intravenous administration of the tracer dose. There were distinct differences in the patterns of tissue distribution between 14C-OA, 131I-OA, and 131I-LOA. Radioactivity concentration in the myocardium was the highest at all time intervals in the rats given 131I-OA only. In dogs, the myocardial uptake of 131I-OA was significantly higher than the radioactivity in the blood or other tissues at 30 min after injection. The disappearance rates of 131I-OA and 131I-LOA were almost identical but myocardial concentration of 131I-LOA at 30 min after the dose in the dog was half that of 131I-OA whereas 131I-LOA liver concentration was higher than that of 131I-OA. Since the concentrations of our formulated 131I-OA in the blood and in the myocardium are both highest at the earlier intervals, it should be difficult to detect myocardial ischemia or infarction with 131I-OA scanning.

Animals↗

A new and superior adrenal scanning agent, NP-59.

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.

Adrenal Gland Diseases↗

Establishment of a nuclear pharmacy.

The University of Michigan Regional Nuclear Pharmacy is described. The scope of operation of the nuclear pharmacy includes radiopharmaceutical formulation and dispensing, quality control, inventory control, research and development of new radiopharmaceuticals, and consultation. Also discussed are program objectives, pharmacy location, organizational structure, budget and staff, economic considerations, facilities and equipment, and legal considerations.

Costs and Cost Analysis↗

Concentration of dopamine analogs in the adrenal medulla.

Seven labeled sulfonanilide analogs of dipamine were synthesized and their tissue distribution in rats were determined as a function of time. The methanesulfonanilide derivative, NP-27, showed significant uptake and retention in the rat adrenal, with 0.66% dose/gm at 5 min and 0.27% dose/gm at 24 h. The 24-hr target-to-nontarget concentration ratios for the adrenal versus liver, blood, kidney, and heart were 13, 27, 30, and 60, respectively. These results compared reasonably with the corresponding target-to-nontarget ratios of 23, 45, 8, and 15 obtained for 14C-dopamine. The six other analogs showed considerably less uptake and retention. Further evaluation of NP-27 in dogs indicated selective uptake in the adrenal medulla.

Adrenal Gland Diseases↗

Effect of large doses of 131I-19-iodocholesterol on metapyralone-induced adrenal cortical hyperplasia in dogs.

The potential use of 131I-19-iodocholesterol to treat ACTH excess Cushing's disease was evaluated in the dog. Three normal female dogs were given LD50 radiation doses of 131I-19-iodocholesterol without producing gross or histopathologically demonstrable change of the adrenals at autopsy 3 months later. The adrenal cortices of three dogs were made hyperplastic (to simulate the adrenal cortex in Cushing's disease) with ACTH and three with Metapyralone. In addition these six dogs were given KD50 doses of 131I-19-iodocholesterol. Three months after treatment, the adrenal glands of the ACTH-treated dogs were not enlarged, the cortex was thicker than normal, and there were no changes attributable to irradiation. At 3 months, the Metapyralone-treated dogs had enlarged adrenals, widening of the adrenal cortex, and no necrosis or other changes attributable to irradiation. It is concluded that a therapeutic trial of 131I-19-iodocholesterol in the treatment of Cushing's disease is not indicated.

Adrenal Cortex↗

Tissue distribution of 14C-, 125I-, and 131I-diphenylhydantoin in the toadfish, rat, and human with insulinomas.

Carbon-14-diphenylhydantoin (DPH) concentrated maximally in pancreatic islet cells of the toadfish 10 min after its intravenous administration. The islet cell-to-acinar-tissue ratio at this time was 6:1. The islet cell-to-liver ratio was 20:1. Iodine-125-paroiodo-DPH at 10 min in the toadfish showed an islet cell-to-acinar-tissue ratio of 1.7:1 and an islet cell-to-liver ratio of 2.3:1. When 14C-DPH was given to four patients 10-17 min before removal of norma pancreatic tissue and of an insulinoma in three of the patients, the concentration of radioactivity in the insulinoma was never greater than in the pancreas and concentrations in insulinoma and pancreas were always less than in liver in the same individual. Forty-five to 90 min after administration of 131I-DPH, the liver and pancreas were delineated in three patients but the insulinoma was not imaged. Five days after administration of 131I-DPH, the concentration of 131I radioactivity in excised tissue was greater in the insulinomas than in the pancreas of two patient but not sufficient to produce positive images of the insulinoma in the pancreas.

Adenoma, Islet Cell↗

Relative tissue distribution of radioactivity in rats with endocrine "autonomous" breast carcinomas after 3H-,99mTc-, and 64Cu-bleomycin.

The localization of 64Cu-, 3H-, and 99mTc-labeled bleomycin was studied in tissues of Fisher rats bearing an endocrine autonomous breast tumor. The 64Cu-bleomycin showed a greater uptake than 3H- and 99mTc-bleomycin in the breast tumor at all time intervals studied, from 2 to 72 hr after the tracer. This same differential uptake was shared by the liver and kidney.

Animals↗