The UW solution for canine kidney preservation: Its specific effect on renal hemodynamics and microvasculature

The preservation effects of UW solution on renal hemodynamics and microvascular systems were studied in canine kidney autografts. In 72-hr UW-preserved kidneys, the microvessels of both cortex and medulla were completely visualized with silicon rubber compound 1 hr after reperfusion. Histology also showed extremely well-preserved arterioglomerular and tubular systems. These results were correlated with good renal blood flow, prompt recovery of posttransplant graft function, and 100% two-week survival of dogs. In contrast, kidneys preserved for 72 hr with Euro-Collins solution showed necrotic and obstructive changes of the microvasculature and deterioration of renal hemodynamics. In 120-hr UW-preserved kidneys, the microcirculation of the medullary region became poor after reflow when there was fairly intact perfusion of the cortical region, indicating an ischemia-related intrarenal blood flow maldistribution. The 120-hr kidneys subsequently failed in spite of having a good blood flow and morphologically well-maintained microvasculature after reperfusion. These data demonstrated that much, but not all, of the beneficial effect of UW solution in kidney preservation might be attributed to its remarkable protection of renal microvasculature. Correction of intrarenal blood maldistribution caused by a discrepancy in tolerance to ischemia of the vascular and tubular systems might be important in successfully preserving the kidney for 120 hr. © 1989 by Williams & Wilkins

Spin Excitation Spectrum of La1−xAx_{1-x}A_xMnO3_3

As an effective model to describe perovskite-type manganates (La,$A$)MnO$_3$, the double-exchange model on a cubic lattice is investigated. Spin excitation spectrum of the model in the ground state is studied using the spin wave approximation. Spin wave dispersion relation observed in the inelastic neutron scattering experiment of La$_{0.7}$Pb$_{0.3}$MnO$_3$ is reproduced. Effective values for the electron bandwidth as well as Hund's coupling is estimated from the data.Comment: 10 pages LaTeX including 4 PS figure

Induction of graft acceptance after dog kidney or liver transplantation

We have reported that, a short delayed course of intramuscular FK 506 can induce a,donor strain-specific immunologic unresponsiveness to cardiac allograft in rats.1 Further studies have been performed to determine if this agent can induce graft acceptance after canine renal (KT) or hepatic (OLT) allotransplantation. Preliminary descriptions of these efforts have been published.

Recent advances in hepatic transplantation at the University of Pittsburgh.

FK506 undoubtedly improved the survival advantage of hepatic allotransplantation. Hepatic-intestinal and multivisceral transplantation has also become a feasible therapy for patients with combined intestinal and liver failure. With better understanding of the immunologic and metabolic aspects of allo- and xenotransplantation, further clinical attempts to transplant animal organs to humans may be considered with the hope for a better outcome in the very near future

Exact time correlation functions for N classical Heisenberg spins in the `squashed' equivalent neighbor model

We present exact integral representations of the time-dependent spin-spin correlation functions for the classical Heisenberg N-spin `squashed' equivalent neighbor model, in which one spin is coupled via the Heisenberg exchange interaction with strength $J_1$ to the other N-1 spins, each of which is coupled via the Heisenberg exchange coupling with strength $J_2$ to the remaining N-2 spins. At low temperature T we find that the N spins oscillate in four modes, one of which is a central peak for a semi-infinite range of the values of the exchange coupling ratio. For the N=4 case of four spins on a squashed tetrahedron, detailed numerical evaluations of these results are presented. As $T\to\infty$, we calculate exactly the long-time asymptotic behavior of the correlation functions for arbitrary N, and compare our results with those obtained for three spins on an isosceles triangle.Comment: 9 pages, 8 figures, submitted to Phys. Rev.