used during perfusion storage, so that the kidneys were not subjected to the greater changes in temperature that would have occurred if ice cooling had been used. Dempster described using slow release of the vascular clamps at the end of kidney reimplantation operations to avoid injuring the kidney, but other workers have not mentioned whether or not they used this manoeuvre. After Cohen found vascular injury with intra renal bleeding after 3 days of perfusion storage, a technique of slow revascularisation was used for all subsequent experiments, with the aim of giving the intra- renal vessels time to recover their tone sufficiently to prevent full systolic pressure being applied to the fragile glomerular vessels. The absence of gross vascular injury in his later perfusions may be attributable to the use of this manoeuvre. See also Artificial organ Cryopreservation References Cryobiology Medical technology Transplantation medicine