Orthotopic liver allografts in the pig

The results obtained in fifty-two orthotopic liver allografts in unselected pigs without the use of immunosuppressive therapy are reported. One third of the animals showed classic signs of rejection. The others tolerated the liver allograft for a relatively long time, five animals living over one year.     

The role of the surgeon in percutaneous transluminal dilation of coronary stenosis.

Percutaneous transluminal dilation (PTD) of coronary artery stenosis is performed by means of a balloon-tipped catheter introduced from a peripheral artery. It was attempted in 45 patients; stenosis was passed in 33 and was successfully dilated in 28 patients (62%). The method failed in 17 patients: in 6 of them an abrupt closure of a stenosed artery or a beginning infarction necessitated an emergency revascularization. There were no deaths or serious complications, but an infarction developed in 1 patient despite immediate bypass grafting. PTD was successful in 5 out of 7 patients who had recurrent angina after previous coronary bypass grafting: in 2 of them stenosis of a distal coronary artery and in 3 a stenosed bypass graft were dilated. PTD is a new method of treatment of coronary artery disease and is an addition rather than an alternative to coronary bypass grafting. The best results can be expected in patients with single-vessel disease, with a short history of angina (less than 1 year), and with narrow, noncalcified proximal stenosis. Some late complications of bypass grafting are also amenable to this method of treatment.     

Histopathology of skin, liver, and kidney after epicutaneous administration of five industrial solvents to guinea pigs

The histopathology of the skin, liver, and kidney was studied in guinea pigs after epicutaneous administration of the industrial solvents n-hexane, toluene, carbon tetrachloride, 2-chloroethanol, and n-butyl acetate. Exposure to hexane, toluene, carbon tetrachloride, and 2-chloroethanol caused progressing nuclear pyknosis and junctional separation between the basement membrane and the basal cells. Toluene and carbon tetrachloride did also induce spongiosis appearing before the junctional separation. n-Butyl acetate did not induce any skin lesion. The liver morphology was characterized by hydropic and necrotic changes for carbon tetrachloride and 2-chloroethanol but no changes were observed for the other solvents. The kidney morphology was normal for all exposed animals.     

Activation of hepatic guanylate cyclase by nitrosyl-heme complexes: Comparison of unpurified and partially purified enzyme

The objective of this study was to evaluate the effects of several agents on activation of both unpurified and partially purified hepatic soluble guanylate cyclase by performed NO (nitric oxide or nitrosyl)-heme complexes. Guanylate cyclase was activated by NO complexes of the heme compounds, hematin, hemoglobin, myoglobin, catalase and cytochrome c, and also by the reaction product of NO and ferredoxin, a non-heme, iron sulfur electron transfer protein. NO-lipoxygenase, which contains non-heme iron, did not activate guanylate cyclase. NO-heme complexes activated unpurified enzyme almost equally well in the presence of either Mg²⁺ or Mn²⁺. However, activation of purified (350- to 750-fold) guanylate cyclase was markedly greater with Mg²⁺ than with Mn²⁺. At concentrations that did not alter basal enzymatic activity, Ca²⁺ markedly inhibited guanylate cyclase activation in the presence of Mg²⁺ but not of Mn²⁺. Hemoproteins inhibited activation of unpurified and purified enzyme by NO-heme complexes, and increasing the concentrations of the latter overcame the inhibition. Gel filtration studies indicated that uncomplexed and NO-complexed hematin bind to common or adjacent sites on guanylate cyclase. Whereas dl-dithiothreitol enhanced activation, ferricyanide, cystine, o-iodosobenzoic acid and ethacrynic acid inhibited activation of guanylate cyclase by NO-heme complexes. The data indicate that the effects of these diverse agents on guanylate cyclase activation by preformed NO-heme are similar to their effects on enzyme activation by NO and nitroso compounds, both of which readily form NO-heme complexes. Therefore, the effects of these diverse agents may be on guanylate cyclase rather than on NO-heme formation.     

Single Aortotomy for Multiple Aortocoronary Saphenous Vein Bypass Grafts

A new technique for the proximal anastomoses of saphenous vein grafts in coronary artery bypass operations is described. This technique has several advantages over existing methods and has been shown to be safe and satisfactory in 389 consecutive patients operated on between May, 1978, and May, 1981.