Leslie R. Bennett

Cutaneous lymphoscintigraphy in malignant melanoma

Melanoma commonly metastasizes to the regional lymph nodes. With early melanomas the accepted therapy is local wide excision and regional lymphadenectomy for nodes in the lymph drainage path. For some melanoma sites the lymph node groups that should be removed are obvious; however, for other sites the decision as to which nodes are at risk may present a difficult problem, since drainage from these sites may vary unpredictably from classical anatomic descriptions. We reviewed recent reports from four institutions using four radiocolloids (colloidal 198gold, 99mtechnetium antimony sulfur colloid (99mTcSbSC), 99mtechnetium sulfur colloid (99mTcSC), and micro 99mtechnetium sulfur colloid (micro 99mTcSC)) to determine lymph shed from melanomas. Correlation with surgical findings was excellent. In addition, drainage to second and third nodal groups, some of which were not clinically predictable, was frequently observed. While all four agents gave good scans, 99mTcSC and micro 99mTcSC are probably the best radiopharmaceuticals.

Estimation of Fat Absorption by Monitoring of Expired Radioactive Carbon Dioxide After Feeding a Radioactive Fat

Summary A rapid method for the diagnosis of steatorrhea based upon oral administration of radioactive glyceryl trioctanoate (RATO) and study of its oxidative decarboxylation as determined by monitoring expired C 14 -labeled CO 2 has been presented. Results based upon the testing of 20 controls and 21 patients with steatorrhea of various types clearly separated 15 of the controls from all of the patients with steatorrhea. Fourteen of 21 patients with steatorrhea fell below the lowest value encountered in 20 control subjects. Possible refinements of the technique are worthy of exploration.

THROMBOPHLEBITIS: DEMONSTRATION BY SCINTISCANNING.

We have noticed that collections of radiotracer in the axillary regions are occasionally seen in patients who have undergone pulmonary scanning (Fig. 1). Almost without exception such patients have previously been subjected to venous catheterization for the purpose of administering intravenous fluids. Accumulations of tracer generally are punctate in appearance and are seen either during the time that the catheter is in place, where injection is made through the catheter, or for several weeks following the removal of the catheter. An explanation that appeared reasonable to us was that the endothelial injury with associated clot (fibrin) deposits on the wall of the injured vessel trapped particles of albumin as they passed. An attraction for the macroaggregates of albumin by the fibrin was postulated. The thesis was tested in the laboratory by preparation of a Petri dish filled with serum mixed with macroaggregates of albumin tagged with 99mTc (Fig. 2). This experiment was interpreted as confirming the abi...

The significance of regional pulmonary function changes in bronchial asthma

Abstract Regional ventilation and perfusion relationships were investigated with radioxenon and macroaggregated radioalbumin in thirty-four asthmatic subjects. The results, as well as those of spirometry and blood gas studies, were correlated with the patients symptoms. It was found that all measurements became increasingly abnormal as symptoms increased but were readily reversible with treatment. Areas of hypoventilation generally showed decreased perfusion but perfusion was frequently less affected than ventilation. This ventilation-perfusion imbalance appears to be widespread in asthma and explains the common observation of hypoxemia despite over-all hyperventilation.

Human Cns Perfusion Scanning With 123L-Lodoantipyrine

Regional perfusion scanning of the central nervous system requires lipophilic radionuclides that rapidly penetrate the intact blood brain barrier. The first compound of this type to be developed for human use is 123I-iodoantipyrine. 123I-iodoantipyrine rapidly crosses the blood brain barrier and is flow-limited in its delivery to the brain. This makes possible the CNS perfusion scanning of the human brain, thereby showing regional distribution of microcirculatory blood flow.

Linoleate produces remission in canine mycosis fungoides

Linoleic acid (LA) administered orally as safflower oil (SFO), which is 76% LA, produced remission in 6 out of 8 dogs with mycosis fungoides (MF). Following each feeding of SFO on 5 successive days to a normal dog peak plasma levels of non-esterified (free) LA in excess of 200 microM were observed. No clinical toxicity was observed from the SFO feedings in the normal or MF animals at the levels of SFO (3 ml/kg) used in these studies. However, a marked rise in white blood cells (WBC) and lymphocytes and a marked transient drop in the serum glutamine transaminases SGOT and SGPT was noted both in the normal and MF animals. These effects of LA may be significant for the remission of MF.

Thermal instability of tetrahymena ribosomes: Effects on protein synthesis

Abstract The thermal denaturation curves of ribosomes from two strains of Tetrahymena pyriformis and a wild strain of Escherichia coli have been compared. The Tetrahymena ribosomes show significant denaturation at temperatures close to each strains maximum growth temperature; both are considerably less stable than those of the bacterium. The translational efficiency of each strain was measured by determining the ratio of amino acid incorporation under optimal growth conditions and at temperatures slightly above and below the temperature supporting a maximum growth rate. The same temperature levels which initiate in vitro ribosomal melting cause significant in vivo reductions in the efficiency of messenger translation. The loss in template efficiency does not appear to be associated with any qualitative impairment of the translation of individual messengers, since the size distribution on a molecular sieve (Sephadex G-200) is unchanged.

Effect of Coronary Blood Flow on Radioisotope Dilution Curves Measured by Precordial Scintillation Detection

Two series of animal experiments are reported. In the first of these, the disappearance rates of intravenously injected radioactive boluses were monitored over the heart and from a peripheral artery. The disappearance rate over the heart was shown to be slower than in the artery. In a second series of experiments in which injection was made into the left ventricle or into a coronary artery while sampling from the right side of the heart, it was shown that the coronary transit time was several times longer than the left ventricular transit time. The prolonged presence of the radioactivity in the coronary vascular bed accounts for the difference in the heart and arterial disappearance slopes. A ratio of these two slopes may provide an index of coronary blood flow.

The Lung as a Metabolic Organ

Recently, the lung has received increasing attention as a metabolic organ. In this role, the lung modulates the composition of the arterial blood by several mechanisms: removing active substances from the plasma, releasing substances into the plasma, temporarily holding substances from circulation, and activating or inactivating substances that pass through the lungs. In this report, the procedures proposed by different investigators for in vivo noninvasive assessment of the lung metabolic functions are reviewed. Most procedures are based on an estimation of the clearance of plasma amines by the lung endothelial cells. This clearance is assessed by measuring the lung uptake or the extraction fraction of an intravenously (IV) injected radiolabeled amine. Our own procedure, which assesses the number of free pulmonary endothelial amine receptors, is discussed in detail. In our procedure, the number of receptors was computed using the number of injected molecules of amine and determining the lung extraction fraction of the amine during its first pass through the lungs. In goats, using N-isopropyl-p-iodoamphetamine labeled with 123I as the radiopharmaceutical, the total number of endothelial lung amine receptors was found to be 1.589 X 10(20). The methods for studying the lung metabolic functions, which are discussed in this report can be applied in humans to evaluate either physiological or pathological conditions.

Total and Individual Kidney Function Assessment with Iodine-123 Ortho-iodohippurate

A simple and reliable method of preparing 123l o-iodohippurate (l-123 OIH) is described. The agent was used to evaluate renal function in 329 patients; its use results in significant dose reduction for those with obstruction, hypertension, or transplant. Images from l-123 OIH provide 2.4 times more detectable photons per mCi administered to the patient than images obtained from l-131 OIH. Diagnoses are expected to be more reliable with l-123 OIH due to the decreased random variation of each data point.