No abstract

The chacma baboon (Papio ursinus) is extensively used in South Africa for biomedical research. Being a large primate, it is always necessary to apply some measure of chemical or physical restraint. The physiological effects of placing an animal in a restraint chair are compared with the effects of various chemical agents, such as ketamine, halothane, and ketamine/xylazine combination over 90 min. It was found that ketamine and thiopentone infusion were a satisfactory chemical restraint agent that gave a stable physiological state over 90 min.

The influence of thiopentone intravenous infusion or halothane inhalation on the results of radiorenography was evaluated using, in six chacma baboons (Papio ursinus), 99mTc‐diethyltriamine‐pentaacetic acid (DTPA) as scanning agent. The renogram parameters, which depend on the condition of the cardiovascular system, differed significantly for the two anaesthetic agents. Since anaesthesia is necessary in baboon studies for the duration of renogram acquisition, it is imperative to standardize an experimental procedure which will leave the cardiovascular system relatively stable. From this investigation it seemed most appropriate to use as an anaesthetic a constant intravenous infusion of thiopentone.

Cerebral ischemia is widely studied through the employment of experimental animal models. Incomplete global models such as two-vessel occlusion are relevant in the study of disease states which may attenuate cerebral ischemia. Hyperglycemia is known to worsen the consequences of ischemia but has not been exclusively employed. The two-vessel occlusion model, which is unsuccessful when employed in the absence of hypotension and/or hypoxia, is thus ideal for modification to a hyperglycemic model. We therefore describe an established technique for inducing hyperglycemic cerebral ischemia through modification of the two-vessel occlusion model as well as the procedure subsequently used to confirm cerebral injury. This method produces a larger degree of neural injury in males than in females, with estradiol levels negatively correlated to neural injury, confirming trends in research where estrogen is shown to be neuroprotective. Overall, this data is consistent with findings obtained by other groups, showing the neuroprotective nature of endogenous estradiol in rat models, with cyclic female animals sustaining less neural injury than age-matched male and acyclic female counterparts Furthermore, this technique proves to be simple, highly repeatable and cost effective. In conclusion, the hyperglycemic cerebral ischemia model developed as a modification to the two-vessel occlusion model (with exclusion of hypoxia and/or hypotension) proved successful for the study of cerebral ischemia.