Is rejection a diffuse or localized process in small-bowel transplantation?

Utilization of endoscopy to both visualize and selectively biopsy an intestinal allograft has become the standard for early recognition and treatment of intestinal allograft rejection. Despite the widespread acceptance of the need for selective mucosal biopsies, it has not been shown that the histological features of intestinal allograft rejection are either localized or occur as part of a more diffuse phenomenon within a tubular allograft. To resolve these issues, 88 ileoscopies were performed in 12 small-bowel allograft recipients and mucosal biopsy samples were obtained at 5, 10, and 15 cm, respectively, from the ileal stoma. Each mucosal biopsy was labeled, processed, and evaluated individually for the presence and severity of any evidence for allograft rejection. The data obtained suggest that intestinal allograft rejection is a diffuse process, and biopsies obtained randomly from an ileal graft are likely to demonstrate evidence of allograft rejection when such is present. © 1994 Springer-Verlag New York Inc

Linear and nonlinear particle-magnetohydrodynamic simulations of the toroidal Alfvén eigenmode

Linear and nonlinear particle-magnetohydrodynamic (MHD) simulation codes are developed to study interactions between energetic ions and MHD modes. Energetic alpha particles with the slowing-down distribution are considered and the behavior of n = 2 toroidal Alfv?n eigenmodes (TAE modes) is investigated with the parameters pertinent to the present large tokamaks. The linear simulation reveals the resonance condition between alpha particles and TAE mode. In the nonlinear simulation, two n = 2 TAE modes are destabilized and alpha particle losses induced thereby are observed. Counterpassing particles are lost when they cross the passing-trapped boundary. They are the major part of lost particles, but trapped particles are also lost appreciably

In vitro immunosuppressive effects of FR 900506 on human T lymphocyte alloactivation

FR 900506 (FR) is a new immunosuppressive drug which prolongs allograft survival. Our studies have compared the in vitro inhibitory effects of FR and cyclosporine (CsA) on human lymphocyte proliferation. Considerably lower doses of FR were required to induce inhibition of lymphocyte proliferation induced by concanavalin A (Con A) stimulation or in primary mixed lymphocyte reactions (MLR). Similar differences between FR and CsA were observed with the secondary stimulation of alloactivated T cells generated in MLR or propagated from liver transplant biopsies. These observations provide further evidence that FR is about 500 fold more potent than CsA and may be a useful immunosuppressive agent in organ transplantation

Endotoxemia and human liver transplantation

Ninety liver transplantations were performed in 81 patients. Plasma endotoxin was measured preoperatively, at the end of the anhepatic phase, and on postoperative days 1, 3, and 7. The presence of high endotoxin levels preoperatively and at the end of the anhepatic period was associated with graft failure and a high mortality. Patients with primary nonfunction of their transplants typically had severe endotoxemia. Endotoxemia could be a cause rather than an effect of perioperative complications and graft loss