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Biomedical subjects

S E Halpern

Publications and source records attributed to S E Halpern.

At least 55 records · Page 3Linked to original sources
PubMed1977

Comparison of viable and nonviable tumor uptake of Sc-46, Mn-54, Zn-65, In-111 and Au-195 with Ga-67 citrate in a hepatoma model.

The tissue distribution of Sc-46, Mn-54, Zn-65, In-111 and Au-195 were studied in a rat hepatoma model at various time intervals over a 96 h period. The tumor localizing properties of these isotopes were evaluated by examining their incorporation and clearance from viable and nonviable tumor tissue and determining the critical tissue ratios formed with blood and muscle. In general, the results showed greater uptake in viable than nonviable tumor tissue at early time periods (4-24 h). By 96 h, however, the activity remaining in the nonviable tumor tissue exceeded the quantity in viable tumor tissue. This trend was previously noted for Ga-67. When compared with Ga-67, only Mn-54 among the isotopes studied showed remarkably higher viable tumor/blood ratios (4-24 h, 45:1-83:1 respectively). Manganese-54 also showed highly significant accumulation in cardiac muscle with a heart/blood ratio at 4 h superior to comparable values previously reported for Cs-137 and Tl-201. It is suggested that tumor and heart imaging may be feasible utilizing radioactive manganese (Mn-51 or Mn-52) with the new positron imaging systems.

Animals↗
PubMed1977

Noninvasive determination of glomerular filtration rate using x-ray fluorescence.

Accurate glomerular filtration rates (GFR) can be calculated based on the infusion of small amounts of nonradioactive iothalamate and collection of plasma samples for assay by x-ray fluorescence. This innovation permits frequent clearance determinations in patients without the hazard of repeated radiation exposure and without the necessity of catheterization of the bladder for urine samples. Thus, the technique becomes feasible in children, transplant patients, and other needing accurate and frequent GFR determinations.

Animals↗
PubMed1977

99mTc-thiomalic acid complex: a nonstannous chelate for renal scanning.

Thiomalic acid (monomercaptosuccinic acid) has been labeled with 99mTc without the use of an intermediary reducing agent. Tissue distribution studies in rats following the injection of 99mTc-tagged thiomalic acid (99mTc-TMA) showed 40-48% of the injected dose in the kidneys. Renal incorporation of this compound was influenced by various parameters such a pH, quantity of thiomalic acid, heating time, and the preparation-injection interval. Scintigrams of a midline kidney slice showed that the 99mTc activity concentrated mainly in the renal cortex. As a proposed renal-imaging agent 99mTc-TMA compared favorably with 99mTc-Sn-dimercaptosuccinate and 99mTc-penicillamine regarding the precent incorporation into the kidney and was superior in this respect to 99mTc-Sn-glucoheptonate and 99mTc-Sn-diethylenetriamine pentaacetic acid. The 99mTc-TMA was also shown to be highly stable through 24 hr. The reagent can be made available in kit form and is easily combined with 99mTc in two steps. Finally, the absence of stannous ion in the 99mTc-TMA complex should avoid the problem of interference with other procedures involving pertechnetate 99mTco4- as the imaging agent.

Animals↗
PubMed1977

Tissue distribution studies with radioactive manganese: a potential agent for myocardial imaging.

Manganese, a trace metal, is known to localize in mitochondria. Because mitochondria are abundant in heart muscle, the possible utility of radioactive manganese as a myocardial imaging agent was examined in 25 rats and six dogs. Myocardial uptake of Mn-54 in rats was found to exceed that of thallium-201; myocardium-to-blood ratios averaged 306:1 versus 48:1 for Tl-201. In the dog, uptake of Mn-54 by ischemic myocardium was reduced by 17-75% compared with normal myocardium. Thus, radioactive manganese appears promising as an intravenous myocardial imaging agent, and might be useful in studying the function of myocardial mitochondria by external imaging.

Animals↗
PubMed1977

Of models and men.

Explore the source record for details and available documents.

Disease Models, Animal↗
PubMed1976

Tumor model studies of 131I-tetracycline and other compounds.

Iodine-131-tetracycline (131I-TET) was prepared by allowing tetracycline hydrochloride to react with radioiodide in acidic methanol (labeling efficiency greater than 85%). This preparation was found to be stable at--4 degrees C for at least 72 hr. Some minimal in vivo breakdown did occur. The 131I-TET, 67Ga, and several 99mTc compounds were studied in a rat hepatoma model. The incorporation of the radiopharmaceuticals into the tumor occurred rapidly, with peak levels at 0.5 and 24 hr after injection for 131I-TET and 67Ga, respectively. The clearnace of the radiopharmaceutical from nonviable tumor was slower than for viable tumor, and by 72 hr after injection the greatest concentration of radioactivity appeared in the nonviable fraction. All normal tissues showed faster clearance than did tumor tissue, regardless of viability. Decreasing the quantity of 131I-TET injected increased the percent of uptake in the nonviable tumor tissue but had no effect on the viable tumor uptake. Of the 99mTc compounds studied, the phosphates developed the highest tumor-to-background ratios. Unfortunately these ratios were not as high as those achieved for 67Ga or 131I-TET.

Animals↗
PubMed1976

Thyroid uptake of 131I: further comparisons of capsules and liquid preparations.

Comparisons were made of thyroid uptake of three commercially available preparations of 131I, using a double-blind design, in 125 patients with normal thyroid function. Uptakes with Squibb Iodotope Diagnostic capsules were significantly lower than those with Squibb Iodotope Oral liquid at 4 hr (p less than 0.01) and 24 hr (p less than 0.05) after ingestion in both the general population and in all patients less than 45 years of age. Uptakes of Radiocaps I-131 (Abbott Laboratories) and Iodotope Oral liquid were indistinguishable under identical conditions. Our findings indicate that interference with either absorption or metabolism of a pharmaceutical can result from the vehicle used to administer it.

Administration, Oral↗
PubMed1976

Parameters of liver spleen scans as an indication of portal hypertension.

In 37 patients with suspected portal hypertension, the bone marrow and splenic uptake on 99mTc-sulfur colloid liver spleen scans correlated with increased portal pressures. The degree of increase was not possible to predict from the scans. In portacaval shunt patients, those with normal portal pressures could not be separated from those with elevated pressures on the basis of the scan alone.

Bone Marrow↗
PubMed1975

Abnormal brain scans in adrenal leukodystrophy. A study of three cases.

Brain scintiphotography in three patients with the clinical characteristics of adrenal leukodystrophy demonstrated focal areas of increased uptake of the radionuclide. Histological examination of cerebral tissue corresponding to the abnormal foci on the scan revealed sudanophilic leukodystrophy. These findings suggest that areas of active demyelination, such as occur in adrenal leukodystrophy, accumulate radionuclide. Thus, brain scintiphotography may be useful in the evaluation of patients in whom the diagnosis of adrenal leukodystrophy is being considered.

Adult↗
PubMed1975

Loculation as a contraindication intracavitary 32P-chromic phosphate therapy.

Loculation of instilled 99mTc-sulfur colloid solution in the peritoneal cavity was observed in a patient being considered for intracavitary therapy with 32P-chromic phosphate. Since intracavitary instillation of a therapeutic dose of a radiopharmaceutical agent into a loculated space would risk therapeutic failure and tissue necrosis, prior instillation of a tracer nuclide is recommended to insure adequate dispersion before beginning such therapy.

Child, Preschool↗