Use of a hanging-weight system for isolated renal artery occlusion during ischemic preconditioning in mice.

Renal failure from ischemia contributes to morbidity and mortality. Ischemic preconditioning (IP) represents a powerful strategy for kidney protection, and recent advances in transgenic mice may help elucidate its molecular mechanisms. However, murine IP is technically challenging and experimental details significantly influence results. Thus we developed a novel model for renal IP using a hanging-weight system for isolated renal artery occlusion. In contrast to previous models, this technique eliminates the need for clamping the vascular pedicle (artery/vein). In fact, assessment of renal injury after different time periods of ischemia (10-60 min) revealed highly reproducible increases in plasma creatinine and potassium levels, while creatinine clearance, urinary flow and potassium/sodium excretion were significantly attenuated. Using different numbers of IP cycles, we found maximal protection with four cycles of 4 min of ischemia-reperfusion. In contrast, no significant renal protection was observed with IP of the vascular pedicle. To assess transcriptional responses in this model, we isolated RNA from preconditioned kidneys and found time-dependent induction of erythropoietin mRNA and plasma levels with IP. Taken together, this model provides highly reproducible renal injury and protection by IP, thus minimizing variability associated with previous techniques based on clamping of the renal pedicle. Further studies on renal ischemia/IP in mice may consider this technique.

Bloodless liver resection using the monopolar floating ball plus ligasure diathermy: preliminary results of 16 liver resections.

Blood loss during liver transection and ischemia-reperfusion injury associated with hepatic inflow occlusion are significant drawbacks during liver surgery. Sixteen patients underwent liver resection using the Monopolar Floating Ball (FB) plus LigaSure (LS) diathermy without occlusion of the hepatoduodenal ligament (group FB-LS). The liver parenchyma was precoagulated using the FB, and the uncovered tiny vessels were sealed using LS. Surgical outcomes were retrospectively compared with 16 well matched patients who underwent liver resection using the conventional clamp crushing method with Pringle's maneuver (group CC). The amount of blood loss during liver transection was significantly less in group FB-LS than in group CC [200 ml (0-990 ml) vs. 480 ml (120-1800 ml); p = 0.006]. The median time it took to complete the liver transection was significantly longer in group FB-LS than in group CC [144 minutes (43-335 minutes) vs. 58 minutes (18-94 minutes); p < 0.0001]. Hepatic inflow occlusion was temporally used in five patients in group FB-LS to achieve hemostasis in hepatic venous tributaries for 6, 10, 19, 26, and 61 minutes, respectively. Using these two electronic devices allows liver resection to be safely performed, with the advantage of minimal blood loss and a reduced inflow occlusion period compared to the conventional method. The major disadvantage may be a slower transection speed. A prospective randomized trial is needed to clarify the clinical benefits of liver resections performed using this novel technique.