2,015 research outputs found
Transplantation of the small intestine: the pathologist's perspective.
Small-bowel transplantation is now ready for clinical trials. The surgical techniques and methods for immunosuppression and monitoring bowel status have been developed in animal models over the past 30 years. Several attempts at small-bowel transplantation in humans have already been reported. In the course of future trials, pathologists will be involved in the monitoring of the posttransplant course by mucosal biopsies and functional studies, including maltose and xylose absorption tests. The morphology of rejection has been studied in canine and rat models. Activated lymphocytes and plasma cells infiltrate the lamina propria and invade crypt epithelium, causing "cryptitis." Villous blunting ensues, resulting eventually in necrosis. Graft survival without immunosuppression is about 10 days. Under Cyclosporine immunosuppression, a lymphoplasmacytic infiltrate has been noted around nerves and vessels in the submucosa. The overlying mucosa may be relatively normal. End-stage bowel is characterized by a contracted, scarred mass. Due to the large amount of lymphoid tissue in the allograft, graft-versus-host disease is a significant problem in small-bowel transplantation
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The Problem of the Neurodegenerative Germline: An Ethical Reconsideration in Light of Genetic Engineering Developments
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Preliminary Results of Aerodynamic Heating Studies on the X-15 Airplane
Aerodynamic heating analysis of X-15 aircraft in fligh
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Anthropology and Moral Philosophy: A Symposium on Michael Banner's The Ethics of Everyday Life
The use of FK-506 for small intestine llotransplantation: Inhibition of acute rejection and prevention of fatal graft-versus-host disease
Small intestine allotransplantation in humans is not yet feasible due to the failure of the current methods of immunosuppression. FK-506, a powerful new immunosuppressive agent that is synergistic with cyclosporine, allows long-term survival of recipients of cardiac, renal, and hepatic allografts. This study compares the effects of FK-506 and cyclosporine on host survival, graft rejection, and graft-versus-host-disease in a rat small intestine transplantation model. Transplants between strongly histoincompatible ACI and Lewis (LEW) strain rats, and their Fi progeny are performed so that graft rejection alone is genetically permitted (F1→LEW) or GVHD alone permitted (LEW→F1) or that both immunologic processes are allowed to occur simultaneously (ACI—»LEW). Specific doses of FK-506 result in prolonged graft and host survival in all genetic combinations tested. Furthermore, graft rejection is prevented (ACI→LEW model) or inhibited (rejection only model) and lethal acute GVHD is eliminated. Even at very high doses, cyclosporine did not prevent graft rejection or lethal GVHD, nor did it allow long-term survival of the intestinal graft or the host. Animals receiving low doses of cyclosporine have outcomes similar to the untreated control groups. No toxicity specific to FK-506 is noted, but earlier studies by other investigators suggest otherwise. © 1990 by Williams & Wilkin
Novel Mechanism of Nucleon Stopping in Heavy Ion Collisions
When a diquark does not fragment directly but breaks in such a way that only
one of its quarks gets into the produced baryon, the latter is produced closer
to mid rapidities. The relative size of this diquark breaking component
increases quite fast with increasing energy. We show that at a given energy it
also increases with the atomic mass number and with the centrality of the
collision and that it allows to explain the rapidity distribution of the net
baryon number (-) in central collisions. Predictions for
- collisions are presented.Comment: 10 pages, Latex file and 6 PostSript figures uuencoded in one fil
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