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Biomedical subjects

A M Friedman

Publications and source records attributed to A M Friedman.

At least 55 records · Page 3Linked to original sources
PubMed1980

Manganese-52m, a new short-lived, generator-produced radionuclide: a potential tracer for positron tomography.

A new generator system has been developed using the Fe-52 leads to Mn-52m parent-daughter pair. Fe-52, half-life 8.3 hr, is isolated on an anion-exchange column, and Mn-52m is eluted in hydrochloric acid. Breakthrough is less than 0.01% and the yield is 75%. The 21.1-min half life of Mn-52m is ideal for use in sequential studies, but is long enough to permit radiochemical manipulations to control biodistribution. Animal studies indicate that Mn-52m is an ideal nuclide for myocardial imaging, combining rapid blood clearance and high concentration in the myocardium. An added advantage is that Mn-52m decays 98% by positron emission and is useful for positron computer tomography.

Animals↗
PubMed1980

In vivo stability and distribution of [131I]iodomethyl trimethylammonium chloride: concise communication.

[131I]iodomethyl trimethylammonium chloride (I-131 TMA) was prepared by the isotope-exchange reaction of diiodomethane with Na131I, followed by reaction with trimethylamine. A specific activity of 20 microCi/mg was obtained. Tissue distributions following intravenous injection of I-131 TMA in mice showed that between 10 min and 2 hr, the highest accumulations of radioactivity were in the urine, kidney, and heart. The uptake of this compound in the heart was very rapid, and the levels of radioactivity remained fairly high up to 2 hr. At 10, 30, 60, and 120 min the heart-to-blood ratios were, respectively, 10.2, 7.7, 8.3, and 9.6. Thyroid uptake of this compound in the rats and analysis of urine samples of the mouse indicated no extensive deiodination of the compound in vivo. These results show that this compound does have potential for use in myocardial imaging. In addition, its stability in vivo makes it very useful for the radiolabeling of compounds containing quaternary ammonium moieties.

Animals↗
PubMed1979

Myocardial imaging with 134mCesium. Comparison of scintigraphic and cineradiographic results.

Thirty-four patients had noninvasive myocardial perfusion imaging at rest using 134mCs. The results were compared with the results of coronary cineangiography and left ventriculography. All 21 patients who had abnormal left ventriculograms had corresponding myocardial imaging defects. This group included 14 patients with electrocardiographic evidence of either an old inferior, anteroseptal, anterior, or anterolateral myocardial infarction. Thirteen patients had normal left ventriculograms: this group included 6 patients with 75% or greater obstruction of one or more coronary arteries and 7 patients with normal or insignificantly diseased vessels. Only 2 of these patients had abnormal myocardial images: both had severe obstruction of the proximal left anterior descending artery without collateral filling of this vessel. In the resting patient who has 134mCs myocardial imaging, we concluded that we primarily are visualizing varying degrees of scarred myocardium rather than reversibly ischemic myocardium.

Adult↗
PubMed1976

Bone marrow scanning with 52iron (52Fe). Regeneration and extension of marrow after ablative doses of radiotherapy.

Extensively irradiated patients were studied from 0 to 73 months after irradiation by 52Fe bone marrow scanning. Marrow regeneration was observed in most patients after intervals of 12 months or longer. The degree of recovery was not dose-related and the marrow ablative dose was not defined with doses of 4000-5000 rads. Degree of recovery depended more upon the antomic region and/or sequence of fields treated; the last field treated invariably showed poorer regeneration when recovery was uneven. Active erythropoisis expanded into distal inactive erthropoietic sites from 3-12 months after irradiation and then decreased thereafter. Blood count cytopenias were almost always restricted to the first year after irradiation.

Adolescent↗
PubMed1976

Definition of myocardial perfusion by continuous infusion of krypton-81m.

Krypton-81m, a radionuclide emitting a 190 kev gamma ray, has a half-life of 13 seconds. It is a radioisotope of an inert water-soluble noble gas and is produced at a constant rate by spontaneous decay of rubidium-81 in an 81Rb-81mKr generator-delivery system. Delivery is through a minibore Teflon catheter that can be threaded through a standard no. 7 or 8F angiographic catheter. The generator is eluted by 5 percent dextrose-in-water, delivered by infusion pump at 1.5 ml/min, and the eluate is infused intraarterially directly into any organ. Delivery and decay reach equilibrium within 2 minutes, producing a heterogeneous distribution that is proportional to the perfusibility of the tissue concerned and the time required to reach it. The ultrashort halflife of the radionuclide rapidly eliminates activity when delivery ceases; thus, experiments can be sequentially repeated at brief intervals. The radiation hazard for easily imaged doses is negligible. Preliminary studies in open chest dogs were visualized by scintillation camera, stored on digital data disk, processed, and displayed in dual channel, dual color mode on a video system. Images of myocardial perfusion defined relative levels of perfusion, collateral circulation between coronary arterial branches, equilibrium time of diffusible perfusion of the myocardium, focal defects in induced occlusion, collateral circulation to occlusion, and reactive hyperemia after release of induced coronary occlusion. The system and technique appear applicable to human subjects.

Animals↗