Effect of radiofrequency ablation of renal tumors on renal function in patients with a solitary kidney.

OBJECTIVE: The purpose of this study was to evaluate the effect on renal function of percutaneous radiofrequency ablation of renal tumors in patients with a solitary kidney. CONCLUSION: Ablation resulted in complete tumor eradication, and there were no serious complications. Percutaneous radiofrequency ablation of renal tumors resulted in a 16% increase in serum creatinine concentration and a 13% decrease in creatinine clearance in patients with one kidney. These results are comparable with those of surgical resection of tumors in this group of patients.

Sex and rat strain determine sensitivity to kappa opioid-induced antinociception.

RATIONALE: Recent studies indicate that sex and rodent strain are determinants of sensitivity to opioid-induced antinociception. OBJECTIVES: The present study examined the influence of sex and rat strain on kappa opioid-induced antinociception using a series of kappa opioids that vary in their relative effectiveness. METHODS: In a warm-water (50, 52 and 55C) tail-withdrawal procedure, the antinociceptive effects of kappa opioids were determined in male and female rats of the F344, Lewis and Sprague-Dawley (SD) strains. RESULTS: In both males and females of each strain, spiradoline produced high levels of antinociception across all nociceptive stimulus intensities, whereas U50,488 produced high levels only at the low and moderate nociceptive stimulus intensities. Sex differences in the potency and effectiveness of these kappa opioids were relatively small and not consistently obtained. Enadoline, bremazocine and nalorphine were less effective than spiradoline in producing antinociception, and at low and moderate nociceptive stimulus intensities these opioids were both more potent and effective in F344 and SD males than their female counterparts. In contrast, in Lewis rats, only bremazocine was more potent and effective in males. In combination tests, bremazocine shifted the spiradoline dose-effect curve leftward and/or upward in males and rightward in females (i.e., antagonized spiradoline). In contrast, in both males and females enadoline shifted the spiradoline dose-effect curve leftward and/or upward. CONCLUSIONS: These data indicate that kappa opioids were generally more potent and effective as antinociceptive agents in males than females. Similar to data obtained with micro opioids, the magnitude of these sex differences was generally larger with the less effective kappa opioids and determined, in part, by rat strain and nociceptive stimulus intensity.