Yuuji Tanaka

Microvascular changes of the liver preserved in UW solution: Pathological and immunohistochemical examination

Rat livers preserved in University of Wisconsin (UW) solution for 24 h were compared with those preserved in Euro-Collins (EC) solution before and after liver transplantation using an immunohistochemical method. Tissue ATP and total tissue adenine nucleotide (TAN) were measured using HPLC. The levels of TAN in the UW group or the EC group were significantly low compared with the control group (no preservation) after 24-h storage. In the EC group, the levels of tissue adenine nucleotides (TAN) decreased 1 h after reperfusion and never reached control levels. In the UW group, the levels of TAN increased a little 1 h after reperfusion and increased more 3 h after reperfusion. After 24-h preservation, the expression of factor VIII-related antigen (FRA) in endothelial cells of central veins was weak in the EC group; in the UW group, FRA was clearly detected in these cells. After reperfusion, although severe endothelial cell damage to the central veins and numerous FRA-positive substances were observed in EC group, endothelial cells of central veins retained their normal structure and FRA-positive substances were rarely noted in the UW group. In both groups, no endothelial changes were detected in portal veins. From these results, it is concluded that UW solution prevents endothelial cell damage and microcirculatory injury in zone III during the preservation period resulting in prevention of initial graft nonfunction. Also, measurement of the TAN level after reperfusion is useful to predict the function of the graft.

On the singular sets of solutions to the Kapustin–Witten equations and the Vafa–Witten ones on compact Kähler surfaces

This article finds a structure of singular sets on compact Kähler surfaces, which Taubes introduced in the studies of the asymptotic analysis of solutions to the Kapustin–Witten equations and the Vafa–Witten ones originally on smooth four-manifolds. These equations can be seen as real four-dimensional analogues of the Hitchin equations on Riemann surfaces, and one of common obstacles to be overcome is a certain unboundedness of solutions to these equations, especially of the “Higgs fields”. The singular sets by Taubes describe part of the limiting behaviour of a sequence of solutions with this unboundedness property, and Taubes proved that the real two-dimensional Haussdorff measures of these singular sets are finite. In this article, we look into the singular sets, when the underlying manifold is a compact Kähler surface, and find out that they have the structure of an analytic subvariety in this case.