Avoidance of ice formation during cooling can be achieved by vitrification, which is defined as solidification in an amorphous glassy state that obviates ice nucleation and growth. We show that a vitrification approach to storing vascular tissue results in markedly improved tissue function compared with a standard method involving freezing. The maximum contractions achieved in vitrified vessels were >80% of fresh matched controls with similar drug sensitivities, whereas frozen vessels exhibited maximal contractions below 30% of controls and concomitant decreases in drug sensitivity. In vivo studies of vitrified vessel segments in an autologous transplant model showed no adverse effects of vitreous cryopreservation compared with fresh tissue grafts.
Tandem scanning confocal microscopy (TSCM) is a noninvasive form of vital microscopy that can be used to evaluate superficial uriniferous tubules in living kidneys. Because TSCM has a number of advantages over conventional microscopic examination of renal biopsies, the present study was undertaken to determine whether the histopathological images obtained by TSCM correlate with post-transplant renal function. The kidneys of New Zealand male rabbits were harvested, flushed with Euro-Collins solution, and stored at 0–2°C for periods of 24, 48, 67 and 72 h prior to transplantation. TSCM observation of the kidneys prior to their transplantation revealed characteristic histopathological changes of the superficial proximal convoluted tubules that correlated closely with subsequent post-transplant renal function. These observations indicate that TSCM may be of significant value in evaluating the status of donor kidneys prior to their transplantation.
Cryopreservation of solid organs might be possible using a mixture of cell-permeable agents, cryoprotectants (CPA), which are designed to completely preclude ice crystal formation during cooling to cryogenic temperatures. The effects of a specific prototype solution (VS4) were evaluated by normothermic blood perfusion in vitro. Rabbit kidneys were divided into three groups: untreated controls (n = 7), Euro-Collins (EC)-perfused controls (n = 6) and VS4 (4970, w/v) CPA-perfused kidneys (n = 7). After a 2-h blood perfusion, five of the seven CPA-perfused kidneys developed polyuria (0.21 mlxmin-'xg-') relative to untreated controls (0.07 mlxminp'xg-') or EC-perfused kidneys (0.06 mlxmin-'xgp'), owing to the lower reabsorption of water (34.3%), Naf (34.2%) and glucose (35.6%). Furthermore, two kidneys were non-functional with virtually no urine production. Reduced tubular function was associated with reduced oxygen consumption (3.6 versus 2.3 versus 2.0 pmolexmin-'xgp' for controls, EC-and CPA-perfused kidneys, respectively) and increased weight gain (17% versus 20% versus 30%, respectively) after blood perfusion. Therefore, the current results provide insight into both the physiological effects of VS4 and the limits of reversibility of renal pathophysiological states. Our results also indicate that in vitro monitoring of oxygen consumption and weight gain of perfused organs could be used as predictors of renal function.
Sex related differences in the blood protein patterns of male and female rats and humans have been studied by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. In rats, a prominent band of mol.wt. 74000--78000 is seen in females in far greater quantity than in males, castrated males or ovariectomized females. A secondary band of 100000 is seen under non-reducing conditions in female rats that is absent in males. In humans, bands of 92000 and 88000 mol.wt. appear to be variable in concentration in men although relatively constant in women. The above differences are observable only if serum albumin is removed from the samples before electrophoresis. The results suggest that each sex has its own characteristic blood protein pattern.
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