Bypass vein grafts in patients with distal popliteal artery occlusion

The results obtained by placing reversed autogenous saphenous vein bypass grafts in either isolated popliteal artery segments or tibial vessels distal to the popliteal artery segments or tibial vessels distal to the popliteal artery are compared. Fifty-five patients with arteriosclerotic peripheral vascular disease who were threatened with limb loss were followed up from six months to nine years prior to this report. The success rate at one year was 94 per cent for the isolated popliteal segment grafts and 73 per cent for the tibial vessel grafts. The success rate after four years was 70 per cent for the isolated popliteal segment grafts and 63 per cent for the tibial vessel grafts. The clinical factors associated with the success of isolated popliteal segment bypass grafts and the factors apparently associated with failure of vein grafts in both of these groups with very poor distal arterial outflow are discussed. Our results suggest that either an isolated popliteal artery segment graft or a tibial vessel graft is a satisfactory means of treating these patients; however, a graft to an isolated popliteal segment is probably preferable to a graft to a tibial artery.

Effect of rabbit ALG on cadaver kidney transplant survival

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The Effect of Immunoregulatory α Globulin (IRA) upon Lymphocytes in Vitro

An immunosuppressive factor has been extracted from α globulin containing fractions of human plasma proteins, which we have called “immunoregulatory α globubin” (IRA). Cohn fraction IV has been found to contain this material. The IRA has been assayed by its ability to inhibit human blood lymphocyte proliferation induced in vitro by phytohemagglutinin (PHA). The IRA has been effective in reducing PHA-induced proliferation by 75% at doses as low as 0.2 mg/106 cells in 1 ml of culture. Most fractions, however, were active at 2 to 3 mg/ml. We have also found the IRA to suppress lymphocyte proliferation induced by anti-human thymocyte serum and specific antigens. The concentration of IRA necessary to inhibit these weaker mitogenic stimuli was considerably less than that necessary to inhibit PHA response.

The IRA does not act by cytotoxicity, contains no cortisol and does not appear to interact sterically with the stimulating agents. The IRA is not firmly bound to lymphocytes. In inhibiting the PHA response, IRA behaves as a noncompetitive antagonist of the early metabolic events which lead to “lymphocyte activation.”

The role of the graft in the induction of tolerance by antilymphocyte serum and cellular antigen

Intravenous donor antigen in the form of spleen cells can significantly potentiate the effects of ALS in prolonging the survival of skin allografts exchanged across both weak and strong histocompatibility barriers. This effect depends on the proper timing of antigen administration and can result in immunologic unresponsiveness of sufficient strength to permit acceptance of second set grafts. The skin allograft itself apparently plays a role in the establishment of this unresponsive state since ALS and antigen alone followed by delayed allografts at 21 days resulted in normal graft rejection times.

The Effect of Immunoregulatory α Globulin (IRA) on Antigen-Mediated Macrophage Immobilization in vitro

Both human and guinea pig immunoregulatory α globulin (IRA) interfered with the in vitro immobilization of peritoneal macrophages from sensitized guinea pigs by specific antigen. When migration inhibitory factor (MIF) was induced in vitro by exposure of sensitized guinea pig lymphocytes to specific antigen and was then added to cultures of peritoneal macrophages from non-sensitized animals, IRA was unable to block the inhibition of macrophage migration caused by MIF. These results indicate that IRA interfered with antigen-specific immobilization of peritoneal macrophages by interaction with sensitized lymphocytes in the peritoneal cell population and did not block the response of macrophages to MIF.