The effect of submandibular gland removal on testicular and epididymal parameters.

The effect of sialoadenectomy (submandibular gland removal) for four weeks duration was studied in five C3H mice and four sham-operated controls. This preliminary experiment using small numbers of animals indicated that sperm production parameters were lowered in sialoadenectomized animals although there were no significant differences between the sialodenectomized and sham-operated group. In a second experiment using larger numbers of animals, significant differences in testicular weights, epididymal weights, and testis weights were noted. These parameters were reduced only 10-14% from control levels. Epididymal sperm head counts were reduced 10% after sialoadenectomy but the two groups were not significantly different (P less than 0.05). No difference in testicular histology was observed. The present report contrasts to that of Tsutsumi et al. (1986) who indicate that submandibular removal with subsequent depletion of epidermal growth factor (EGF), is extremely deleterious (40-55% decreases in spermatid and sperm content) to the progress spermatogenesis.

Pharmacokinetics of gentamicin in laboratory rabbits.

The pharmacokinetics of gentamicin was studied in 5 healthy adult laboratory rabbits of both sexes. Gentamicin sulfate (5% aqueous solution) was administered rapidly (IV) at a dosage of 3 mg/kg of body weight. Venous blood samples were taken at 0 (baseline), 5, 10, 15, and 30 minutes, and 1, 1.5, 2, 2.5, 3, 4, 5, and 6 hours after gentamicin administration. Serum gentamicin concentration was measured by radioimmunoassay. With the aid of a nonlinear least-squares program, the gentamicin concentration data were found to be best described by a 2-compartment model, with r2 = 0.989. Half-life, as determined from the terminal phase, was 56.6 +/- 2.4 (mean +/- SD) minutes. Calculation of total body clearance provided a mean of 1.69 +/- 0.07 ml/min/kg of body weight. Volume of distribution, calculated from the area under the curve for each animal, was 0.138 +/- 0.005 L/kg.

Ketamine-xylazine anaesthesia in the Djungarian hamster (Phodopus sungorus).

The combination of ketamine-xylazine was assessed as a surgical anaesthetic in Djungarian hamsters acclimatized to both long (16 h light: 8 h dark) and short (8 h light: 16 h dark) photoperiods. It was concluded that 50 mg/kg of ketamine with 10 mg/kg of xylazine or 100 mg/kg of ketamine with 5-10 mg/kg of xylazine when given together by intraperitoneal injection was a satisfactory general anaesthetic. Two hundred mg/kg of ketamine with 10 mg/kg xylazine caused death in 13 of 24 animals. There were no clinically significant effects on depth of anaesthesia due to photoperiod.

Ketamine hydrochloride and xylazine hydrochloride anaesthesia in the golden hamster (Mesocricetus auratus).

The combination ketamine-xylazine was assessed as a surgical anaesthetic in the golden hamster. Several dose levels and routes of injection were evaluated. It was determined that 50-200 mg/kg bodyweight of ketamine with 10 mg/kg body weight of xylazine, when given by intraperitoneal injection, was a satisfactory general anaesthetic.

Restraint device for serial blood sampling of ferrets.

A device was designed that effectively restrained unanesthetized ferrets for serial blood sampling from the caudal artery. Materials used for construction were inexpensive and easily obtained. Fabrication was simple and rapid.

Pharmacokinetics of long acting oxytetracycline in the laboratory rat.

Pharmacokinetic parameters of a slow release form of oxytetracycline were determined in the rat. Triexponential pharmacokinetics were displayed after intravenous administration. The half-life of the distribution phase was 0.097 hours, the rapid elimination half-life was 3.74 hours and the slow elimination half-life was 27.26 hours. Subcutaneous and intramuscular injection resulted in a rapid elimination half-life of 6.09 and 6.02 hours, respectively. In comparison, a standard form of oxytetracycline given subcutaneously had a rapid elimination half-life of 4.22 hours. The slow release form of oxytetracycline has a half-life in the rat long enough to maintain serum levels greater than the minimum inhibitory concentration of Mycoplasma pulmonis with a dose interval of 72 hours.