The pathology of nephrotoxicity of gentamicin in snakes. A model for reptilian gout.

Two gopher snakes (Pitophis melanoleucus catenifer) each were given 5 mg/kg body weight gentamicin every 72 hours (group 1); two snakes each were given 5 mg/kg/day (group 2). Doses for both groups were given over a 2-week period. After the second week, the dose for one snake in each group was increased to 50 mg/kg/day for 2 more weeks and then discontinued. Weekly renal biopsies taken from snakes in group 1 showed no abnormalities by light microscopy during and at the completion of the experiment. Snakes in group 2 had cloudy swelling of the proximal tubules at 2 and 4 weeks after the gentamicin was administered. Snakes given the high dose of gentamicin had hydropic degeneration of the proximal tubules 2 weeks after the dose was raised to 50 mg/kg/day. This progressed to tubular necrosis 1 week after the gentamicin was discontinued. These snakes (high dose) also developed visceral gout, apparently as the result of the extensive tubular necrosis. Tophi were in the pericardium, serosal membranes and parenchyma of the kidneys, liver, spleen and lungs.

Effect of feeding on plasma uric acid levels in snakes.

The effect of feeding on plasma-uric acid concentrations of the snake was studied. The values were monitored in 2 gopher snakes and 2 black rat snakes which were fed mice. Plasma uric acid values in snakes increased after eating and gradually returned to base line with the digestion of the mice. Uric acid concentrations were greater in snakes eating 2 mice than in those eating only 1 mouse. The base-line plasma uric acid concentration in snakes was approximately 2 to 5 mg/dl. Plasma uric acid concentrations may be useful in making a diagnosis of gout. Presence of gout is usually indicated by increased uric acid concentrations; however, interpretation of these concentrations should be based on information about the feeding schedule.

Blood volume measurements in gopher snakes, using autologous 51Cr-labeled red blood cells.

Blood volume determinations were performed in 5 anesthetized gopher snakes (Pituophis melanoleucus catenifer) by means of a 51Cr-labeled red blood cell (RBC) method. The mean blood volume was 52.8 ml/kg of body weight (+/- 6.21 SE). Previous blood volume measurements have not been reported for this species. The RBC survival rate was estimated to be greater than 660 days. The RBC survival rate is long, but it cannot be determined accurately by this method.

The acid-base status of lions, Panthera leo, immobilized with four drug combinations.

Fifty-eight immobilizations were conducted using 21 lions (Panthera leo) and 4 drug combinations. The combinations used were ketamine-phencyclidine-promazine, xylazine-phencyclidine-promazine, xylazine-ketamine-phencyclidine-promazine, and tiletamine-zolazepam.

Physiologic measures of nonhuman primates during physical restraint and chemical immobilization.

The arterial acid-base balance and other selected physiologic measures of physically restrained and chemically immobilized nonhuman primates from the families Callithricidae, Cebidae, Cercopithecidae, and Pongidae were compared. The physically restrained primates had significantly lower pH, pCO2, and base excess values, but they had significantly higher pO2 values, rectal temperatures, and pulse and respiration rates. Of 56 physically restrained primates, 30 (54%) experienced severe metabolic acidosis, with pH values less than 7.2; 15 (27% of total) had pH values less than 7.1. Two types of behavior were observed during the physical restraint of golden marmosets. Some of the marmosets were excited during restraint, with a great deal of struggling and vocalizing. The other marmosets were quiet and calm, with minimal struggling. The excited group had significantly lower pH, pCO2, and base excess values, but significantly higher pO2 values, rectal temperatures, and pulse and respiration rates. Primates immobilized with ketamine or tiletaminezolazepam had a near normal acid-base balance and were handled more easily than the physically restrained animals.

Observations on immobilization of Père David's deer.

Etorphine and xylazine were found to be a safe and reliable drug combination for the immobilization of Père David's deer, whether excited or unexcited. Excited deer had a longer preimmobilization period, when compared with unexcited deer at comparable dosages. Generally, the acid-base status of Père David's deer during immobilization was not seriously altered. Deer that had been excited and exercised experienced mild respiratory problems; the unexcited, relatively calm deer experienced minimal acidosis. Significantly high pH and PO2 and significantly lower PCO2 and bicarbonate values were found in the excited deer, when compared with the unexcited deer. Rapid physiologic changes occurred after the intravenous administration of the antagonist, diprenorphine.