A standardized method for quantifying consistent individual differences in schooling behaviour.

A method for quantifying consistent individual differences in schooling behaviour is presented. This method, which utilizes a school of models, improves on previous methods by removing the unwanted variation that is introduced by live stimulus fish while still providing the physiological experience of schooling to the focal fish. Three-spined stickleback Gasterosteus aculeatus observed in the model school assay exhibited consistent individual differences in schooling behaviour.

Sequential transplant of paired kidneys following donation after cardiac death: impact of longer cold ischemia time on the second kidney on graft and patient outcome.

The United Kingdom has no national sharing scheme for kidneys received from donation after cardiac death (DCD). Therefore, both kidneys retrieved by a transplant team are implanted at a single unit, often sequentially. This study analyzes the impact of a prolonged cold ischaemia time on the second transplanted kidney and the effects on short-term and long-term outcomes in all our DCD renal implants from 2002 to 2009. Cold ischaemia time was significantly longer with the second kidney (P = .04) as was delayed graft function (P = .02). Acute rejection was increased in the first transplanted kidney (P < .001). Five-year patient survival was comparable between groups, but 5-year graft survival was higher in the second transplanted group (P = .04). The results confirm that, provided recipient centers are willing to accept higher initial rates of delayed graft function, it is acceptable to transplant DCD grafts sequentially without jeopardizing long-term graft or recipient outcome.

Ischemic epigenetics and the transplanted kidney.

The primary purpose of this investigation was to study oxidative demethylation of DNA following ischemia/reperfusion injury (I/RI) that putatively influences posttransplant gene expression in transplanted kidneys. Our hypothesis was that as a result of I/RI, oxidative damage, which is inherent in solid organ transplantation, may lead to aberrant demethylation of cytosine-guanine (CpG) sites within gene promoter regions of DNA. The methylated CpG sites normally contribute to the binding of proteins that render DNA inaccessible to transcription factors. Therefore, conversion of methylated cytosines to nonmethylated cytosines by oxidative damage in postischemic organs might facilitate enhanced gene expression in donor organs by exposing the demethylated CpG site in a gene promoter to DNA-binding proteins that enhance gene transcription. In this study, we investigated the demethylation of a specific CpG within the IFNgamma response element resident in the promoter region of the C3 gene in the rat kidney. In response to 24 hours of cold ischemia and a subsequent 2 hours of reperfusion in an isolated ex-vivo circuit, we observed a significant change in the ratio of methylated to unmethylated cytosines at this site. Epigenetic modifications to donor DNA have not been previously investigated, but our own data suggests that they have the potential to modify gene expression posttransplantation. Since epigenetic modification may become stable and heritable upon mitosis, such changes to the donor organ DNA may persist with enormous implications for transplant outcomes.