Renal response during acute unilateral ureteral obstruction in rats.

The early renal response to unilateral ureteral occlusion (UUO) and its mechanism have been extensively studied in dogs but seldom discussed in the most frequently used laboratory animals, rats. The acute phase of the renal response to UUO was studied in female rats weighing 190-236 g. We recorded the ureteral pressure and changes in renal parameters throughout 120 minutes of UUO in control (US, UUO + saline, n = 10), L-arginine-treated (UA, n = 10), and right-nephrectomized rats (UO, UUO in one kidney, n = 9). Ureteral pressure increased in all three groups of rats after complete ureteral obstruction. The extent of the increase was not significantly different between US and UA rats but was significantly higher in the UO rats. In US rats, the cortical microvascular blood flow (CMVBF), measured by a laser Doppler flowmeter, declined significantly, from 321 +/- 10 perfusion units (PU) to 260 +/- 11 PU. The percentage of drop in CMVBF at 120 minutes of UUO was significantly greater in UO (25.7 +/- 3.8 %) than in US (19 +/- 2.1%) and in UA (14 +/- 2%) rats. Acute UUO reduced the glomerular filtration rate (GFR) in US and UO rats, whereas L-arginine attenuated this decrease. The excretion of nitrate/nitrite was increased after UUO. Giving N(G)-nitro-L-arginine methyl ester hydrochloride (L-NAME, 12 mg/kg/h) during UUO did not reduce CMVBF more severely. Western blot analysis of endothelial nitric oxide synthase expression in the renal cortex and medulla protein extracts revealed no differences between US and sham-operated rats. Acute UUO did not lead to renal hyperemia in rats. Reduction of nitric oxide during UUO might contribute to the decrease of renal circulation during UUO.

Maternal, fetal, and neonatal effects of lidocaine with and without epinephrine for epidural anesthesia in obstetrics.

The effects of epidural lidocaine with and without 1:300,000 epinephrine on uterine activity, progress of labor, fetal heart rate, maternal blood pressure and heart rate, newborn Apgar scores, neonatal acid-base status, and the Neurologic and Adaptive Capacity Scoring System were compared in 30 parturients during labor and delivery. Patients in group I (n = 16) received 1.5% lidocaine with 1:300,000 epinephrine and those in group II (n = 14) 1.5% lidocaine alone. Addition of epinephrine to lidocaine did not have any significant effects on uterine activity, duration of first or second stages of labor, fetal heart rate variability, or the incidence of abnormal fetal heart rate patterns. Maternal heart rate and the incidence of hypotensive episodes did not differ significantly between the two groups of patients. Apgar scores, neonatal acid-base status, and the NACS were equally good in the two groups. Duration of analgesia was significantly longer in group I as compared to group II patients (106.9 +/- 6.6 vs 66.2 +/- 4.4 min, P less than 0.001). Umbilical venous concentrations of lidocaine and umbilical vein to maternal vein ratios of lidocaine were significantly higher in group II patients (P less than 0.05). It is concluded that addition of epinephrine to lidocaine during epidural anesthesia in the normal parturient has no adverse effects on mother, fetus, neonate, or the progress of labor and it significantly prolongs the duration of anesthesia and limits the placental transfer of lidocaine.