The adverse impact on liver transplantation of using positive cytotoxic crossmatch donors

Because of the liver graft's ability to resist cytotoxic antibody-mediated rejection, it has become dogma that the conventional transplant crossmatch used to avoid hyperacute rejection of other organs is irrelevant to the liver. We examined this hypothesis in a consecutive series of adult primary liver recipients treated with FK506 and low-dose steroids. Twenty-five of 231 (10.8%) patients received a liver from a cytotoxic-positive crossmatch donor (more than 50% of donor T lymphocytes were killed by dithiothre-itol-pretreated recipient serum). The outcome was compared with that of 50 negative crossmatch patients who had their transplantations just before and after the crossmatch positive cases. The one-year graft and patient survivals were 56% and 68%, for positive and 82% and 86% for negative crossmatch patients (P=0.004, P=0.03, respectively). The difference between patient and first graft survival was accounted for by retransplantation, which was 4 times more frequent in the positive-crossmatch cases. Histologically, failed allografts obtained at the time of retransplantation revealed a spectrum of pathologic findings related to vascular injury. This study showed a higher difficulty of intraoperative blood product management, a degraded prognosis, and a poorer average quality of ultimate graft function when liver transplantation was performed against positive cytotoxic crossmatches. In such patients for whom crossmatch-negative donors may never be found because of the broad extent and intensity of sensitization, special therapeutic strategies perioperatively must be evolved if results are to improve. © 1992 by Williams and Wilkins

The Culture of Green: The Role of Cultural Worldviews, Psychological Connectedness, Time Discounting, and Social Norms in Environmental Decisions

In this dissertation, I examine cultural differences in perceptions of time looking at intertemporal decisions, social norms, policy preferences, and behaviors in the environmental domain. Looking closely at the environmental domain allows for a unique opportunity to examine whether or not cultural worldviews or social norms are motivating environmental behaviors (e.g. energy conservation). It is also possible to test whether the uncertain nature of climate change and its impacts over time results in different temporal discounting rates compared to other intertemporal choice domains (e.g. financial gains or financial losses). I draw upon theories of the self to argue that culture affects intertemporal decisions. I describe research supporting culture's effect on how individuals evaluate gains and losses, or benefits and risks, over different temporal horizons. I test whether culture affects temporal orientations, such that cultures that encourage holistic thinking are more likely to view the self and environment as continuous over long time horizons, while those cultures that encourage focused thinking are less likely to see such continuity over time. I next draw on theoretical and empirical evidence from cross-cultural psychology to argue that these country differences in temporal orientations have an effect on intertemporal decisions, examining in particular decisions about environmental policy and energy conservation behaviors. In Study 1, I compare Anglo-Saxon countries with Latin-American countries to look at the role that cultural worldviews (i.e. egalitarian, individualistic, hierarchic, and fatalistic) play in influencing environmental policy preferences and pro-environmental behavioral intentions. In Study 2, I test whether different construals of the self (either independent or interdependent) have an influence, above and beyond worldview effects, on environmental decisions. Finally, in Study 3, I compare Americans and Japanese to look at the effect of psychological connectedness above and beyond its effect on discounting. I also test whether there is cross-cultural variation in expectations in the types of green behaviors (e.g. easy versus hard) to engage in. With the three studies that I summarize in the chapters that ensue, I hope to identify some of the processes by which culture influences environmental decisions

Why is the condensed phase of DNA preferred at higher temperature? DNA compaction in the presence of a multivalent cation

Upon the addition of multivalent cations, a giant DNA chain exhibits a large discrete transition from an elongated coil into a folded compact state. We performed single-chain observation of long DNAs in the presence of a tetravalent cation (spermine), at various temperatures and monovalent salt concentrations. We confirmed that the compact state is preferred at higher temperatures and at lower monovalent salt concentrations. This result is interpreted in terms of an increase in the net translational entropy of small ions due to ionic exchange between higher and lower valence ions.Comment: 4pages,3figure

Cadaveric small bowel and small bowel-liver transplantation in humans

Five patients had complete cadaveric small bowel transplants under FK506 immunosuppression, one as an isolated graft and the other 4 in continuity with a liver. Three were children and two were adults. The five patients are living 2-13 months posttransplantation with complete alimentation by the intestine. The typical postoperative course was stormy, with sluggish resumption of gastrointestinal function. The patient with small intestinal transplantation alone had the most difficult course of the five, including two severe rejections, bacterial and fungal translocation with bacteremia, renal failure with the rejections, and permanent consignment to renal dialysis. The first four patients (studies on the fifth were incomplete) had replacement of the lymphor-eticular cells in the graft lamina propria by their own lymphoreticular cells. Although the surgical and aftercare of these patients was difficult, the eventual uniform success suggests that intestinal transplantation has moved toward becoming a practical clinical service. © 1992 by Williams and Wilkins