Search

The internal mammary artery, when used as a conduit for coronary artery bypass, offers a better long-term patency rate and survival rate than the saphenous vein; however, its utility has been limited. Among other factors, the availability of only two internal mammary arteries for anastomosis has been a major limitation. In an attempt to overcome this limitation, we constructed sequential internal mammary artery grafts in 87 patients. In 49 patients (Group I), only one internal mammary artery was used for sequential anastomosis. In another 31 patients (Group II), one internal mammary artery was used for sequential anastomosis and the other was used for single end-to-side anastomosis. Both internal mammary arteries were used in seven patients (Group III) for the construction of sequential anastomoses. Postoperatively, 64 patients were evaluated by exercise stress tests. None of these patients had a positive stress test although seven patients (11%) had electrocardiographic changes that were considered equivocal. Coronary angiography was performed in 35 of the 87 patients, with 92 vein grafts and 90 internal mammary artery anastomotic sites evaluated within 1 year of operation. A total of 83 vein grafts and 84 internal mammary artery anastomotic sites evaluated within 1 year of operation. A total of 83 vein grafts and 84 internal mammary artery anastomoses were found to be patent. Thus the patency rate for vein grafts was 90 % and for internal mammary artery grafts, 93 %. During the follow-up period (8 to 52 months), three patients died and one was lost to follow-up. Among the remaining patients, 79 had complete relief from symptoms, three had minimal symptoms, and one patient obtained no relief from symptoms. Based on these results, we have concluded that the extended use of internal mammary artery, constructing sequential anastomoses, is technically feasible and provides adequate perfusion to the area of myocardium supplied by such grafts.

This report describes the clinical and immunoglobulin features of a patient with gamma heavy chain disease (HCD), who presented with a clinical picture suggestive of an underlying malignancy rather than the usual picture of lymphoma or granulomatous disease. A unique clinical feature was the nearly total replacement of the submaxillary glands by plasma cells. The patients serum and urine contained a paraprotein, γHCD protein BAZ, which belongs to the γ1 subclass and forms noncovalently linked dimers with a molecular weight of approximately 60,000 daltons. This mutant protein exhibited a deletion which encompassed most of the variable (V) region, the first constant domain (CH1), and the hinge region. In addition, preliminary structural analyses demonstrated the replacement of alanine by glycine in position 431 of the carboxyterminal octadecapeptide. This substitution may possibly represent another allotypic marker on IgG1 proteins.

The liganded derivatives of hemoglobins G Georgia (α295Leu(G2) β2) and Rampa (α295Ser(G2) β2) were found by sedimentation velocity, viscosity, and diffusion measurements to be extensively dissociated into dimers in 0.1 mNaCl at pH 7.2 to 7.4 and 25°. The deoxygenated derivatives of both hemoglobin variants are tetramers under the same conditions. The deoxyhemoglobins also retain a predominantly tetrameric structure in NaCl solutions of increasing concentration up to 2 m, and in dilute alkaline buffers, at least to pH 9.8. In addition, association-dissociation in oxy- or cyanferrihemoglobin Rampa is both pH- and temperature-dependent. The liganded Rampa molecule is primarily a tetramer at 4° in the pH range 6 to 7, whereas liganded hemoglobin G Georgia shows only slightly increased tetramer formation under identical conditions. Both hemoglobin G Georgia and hemoglobin Rampa have decreased heme-heme interactions and increased oxygen affinities.

A urine concentrate from a patient with paroxysmal nocturnal hemoglobinuria contained four regulators of erythro-poiesis that could be isolated by an electro-fractionation technique combined with selective membrane permeability. An erythropoie-sis-stimulating factor (ESF) passed toward the anode through a membrane with a cutoff at a molecular weight of 30,000, but was retained by a membrane with a cutoff at 20,000, while another ESF was retained by a membrane with a cutoff at 50,000. An ESF-generating factor passed toward the cathode through a membrane with a cutoff at 50,000 but was retained by a membrane with a cutoff at 30,000.An inhibitor of erythropoiesis (EIF) passed toward the cathode through a membrane with a cutoff at a mol wt of 30,000 but was retained by a membrane with a cutoff at 10,000. The EIF brought about maximal depression of erythropoiesis 6 days after the first of four daily injections, but erythropoiesis gradually returned to normal 3 days later, though the EIF injections were continued. The EIF appeared to be mostly lipid and about 7.5% protein.The authors express their appreciation to members of the engineering departments at the Veterans Administration Hospitals in Augusta, GA and St. Louis, MO for their assistance in the construction of the electrofractionation apparatus used in this work.