Radioisotopic pulmonary lobectomy: feasibility study in dogs.

In search for an alternate treatment for inoperable cancer of the lung in humans, we investigated the possibility that introduction of radioactive material into a selected lobe of the canine lung would effectively destroy that lobe without systemic effects or radiation injury to adjacent organs. Ten million ion exchange microspheres labeled with 740 MBq of phosphorus-32 (32P) were injected through a catheter placed in a selected lobar branch of a pulmonary artery in 12 anesthetized dogs. Six additional dogs served as controls and received 10 million microspheres not labeled with 32P. Organs were harvested from 1 wk to 12 mo after injection and examined grossly and histologically. There was progressive organization and contraction of each necrosed 32P treated lobe which was reduced to a scarred remnant by 12 mo, whereas only minimal inflammatory changes occurred in controls. Of the 32P injected dose, 94% remained in injected lobe, 4%-5% in nontargeted lobes and less than 0.08% in blood. Radioactivity in liver, kidneys, spleen, heart, and bone marrow was less than 0.1% for each organ. Thus, large doses of radiation in the order of 1,500 Gy can be effectively delivered to a selected lobe to produce a "radioisotopic pulmonary lobectomy."

Serial measurement of portal hemodynamics after partial portal decompression.

In a serial analysis of splanchnic hemodynamics, we compared partial with total portal decompression in 16 alcoholic cirrhotic patients who underwent portacaval shunts for variceal hemorrhage. Partial decompression was achieved with 8 or 10 mm polytetrafluorethylene portacaval H grafts and aggressive collateral ligation. Total decompression was achieved with larger diameter H grafts (12 or 14 mm). Early and follow-up (mean interval, 18 months) postoperative studies of portal hemodynamics included: direct measurement of shunt gradients, scintigraphic quantitation of portal and mesenteric flow distribution to the liver, and a portal and splenic collateral scoring system developed from standardized splenic venography. Partial portal decompression reduced portal pressure by 43% +/- 8% compared with 81% +/- 5% after total decompression (p less than 0.01). Scintigraphy demonstrated that partial decompression provided a greater fraction of portal flow to the liver than did total decompression (57% +/- 9% versus 2% +/- 1% intrahepatic radioactivity) and mesenteric flow distribution (14.5% +/- 5.4% versus 1.2% +/- 0.7%). Only one patient with partial decompression had a significant loss of portal perfusion during the interval studies. Significantly more residual collaterals were visualized in patients with partial decompression than in those with total decompression, and interval studies showed no significant changes from early studies. We conclude that partial decompression maintains higher portal pressures, more residual collaterals, and a greater fraction of portal and mesenteric flow to the liver than does total decompression. A modest but uniform reduction of portal pressure minimizes stimulus for new collateral formation and further shunting of portal flow.

Detection of bacterial endocarditis with technetium-99m-labeled antistaphylococcal antibody.

The reliable diagnosis of bacterial endocarditis is an important but difficult clinical problem. The potential ability of technetium-99m-labeled antistaphylococcal antibody to detect infective endocarditis was investigated in a rabbit model. Radiolabeling of the purified antibody was effected by a mild electrolytic procedure, with full retention of immunologic activity. Infective endocarditis was induced in rabbits by placing a catheter through the carotid artery into the left ventricle, followed by i.v. injection of Staphylococcus aureus. The labeled antistaphylococcal antibody was subsequently injected, and its clearance and distribution were studied in the infected rabbits and in normal controls. The ratio of radioactivity on the aortic valve to that in the surrounding heart tissue or blood pool was significantly higher for the infected animals (> 10:1) than for the normals, and should permit visualization of the infection site. This radiolabeled antibody technique may provide a feasible approach to detection of infective endocardial lesions.