Resistive index of the solitary kidney a clinical study of normal values

We studied changes in the renal hemodynamics and renal resistive index [RI] of the remaining kidney after live donor nephrectomy. The study included 24 healthy live kidney donors [14 males and 10 females] with a mean age of 42 years. After donor evaluation Doppler ultrasound was done of the 2 kidneys the day before nephrectomy with RI measurement of each kidney. After nephrectomy the RI of the remaining kidney was measured on days 2, 4, 6, 8 and .10, and then at weeks 2, 3, 6 and 12. Mean RI of the remaining kidney before nephrectomy was compared to values at different time points after nephrectomy. Changes in the RI of the remaining kidney were screened at the follow up time points. There was no difference between the mean RI of the right and left kidneys before nephrectomy [0.67 +/- 0.04 and 0.67 +/- 0.04, respectively]. The RI of the remaining kidney increased from 0.67 +/- 0.04 before nephrectomy to 0.71 +/- 0.06 on day 2 after nephrectomy, which was significantly different [p<0.0001]. The mean RI increase of the remaining kidney on day 2 was 0.05 +/- 0.03. The RI of the remaining kidney remained almost stable on days 4, 6, 8 and 10, and also at week 2. Comparison between the mean RI at weeks 2 [0.72 +/- 0.05] and 3 [0.73 +/- 0.05] showed a further increase of significant value [p<0.0001]. The mean RI remained stable at weeks 6 [0.73 +/- 0.05] and at 12 [0.73 +/- 0.05,]. The RI of the remaining kidney signf1cantLy increases after nephrectomy of the contralateral kidney. Therefore, an RI value of 0.7 is not suitable to diagnose a pathological condition in a solitary kidney in adults

Effect of leptin on renal functions in rabbits

The aim of this work is to evaluate the hemodynamic changes of leptin administration to rabbits. A total of 18 male New Zealand rabbits, weighing from 1 to 1.5 kg were included in this study. After induction of anesthesia, basal arterial blood pressure [Am, sodium [Na+], potassium [K+] and creatinine concentrations in both blood and urine samples were evaluated. The animals were then randomly assigned to 3 groups of 6 each. Group I [control] received isotonic saline by intravenous infusion. Group II [study group] received intra-arterial injection of leptin [10 micro g/kg] for one Hour followed by a 10-Jold higher dose of leptin. Group III [negative control] received intravenous bolus injection of propranolol [0.1 mg] for one hour followed by a similar dose for the next hour. Administration of leptin resulted in slight increase in mean arterial pressure [MAP] that reached significance after 90 min and persisted above the basal level for the recording period of 2 hours. There were no parallel changes, at either doses, infraction reabsorption of Na+, K+, H20 and glomerular filtration rate [GFR] as compared to both basal values and to control animals. It was concluded that the elevation in MAP induced by leptin was most probably not related to renal mechanism, as there were no significant changes in renal parameters studied. This suggests another mechanism for the rise in MAP, a suggestion which needs further studies