The 'lung in shock' as a result of hypovolemic-traumatic shock in baboons.

The "lung in shock" syndrome is a constellation of early morphologic changes in the lung within 1 hour after polytrauma as indicated by human lung biopsies. A hypovolemic-traumatic (soft-tissue trauma together with bone fractures) baboon model with reinfusion was established to study these morphologic and associated pathophysiologic events. This model was developed in order to test the efficacy of therapeutic modalities in future studies. Nineteen baboons (eight sham, 11 shock) were anesthetized with spontaneous respiration while complete hemodynamic and blood gas monitoring was performed, along with light and electron microscopic studies of the lungs. Besides the usual shock-related hemodynamic disturbances and the metabolic acidosis, pathologic changes were found both on light and electron microscopy of the lungs but not on X-rays and measurements of blood oxygenation. In the shock group, morphologic evidence of endothelial and interstitial edema was associated with significant increases in lung weight. The fluid accumulation occurred in spite of careful control of pulmonary artery pressures during the study. More striking histologic findings were significant cellular infiltration of lung tissue, especially by leukocytes, showing evidence of degranulation. This baboon study, similar to studies undertaken in canines, shows that the hypovolemic (hemorrhagic) shock in association with trauma (fracture, soft-tissue trauma) causes ultrastructural morphologic changes that may precede potentially life-threatening functional changes in the lung.

Evaluation of kidney function in dogs suffering from canine encephalitozoonosis by standard clinical pathological and radiopharmaceutical techniques.

Canine encephalitozoonosis can be responsible for a severe renal disease in dogs which may develop into progressive, irreversible kidney failure. Three pure-bred Boxer littermates with confirmed encephalitozoonosis were subjected to sequential clinical pathological tests and renal biopsies. The endogenous serum creatinine and urea levels showed an initial temporary reduction but later increased steadily. The phenolsulphonphthalein retention test confirmed this end-stage renal disease. Initial hyper-gamma globulinaemia showed a rapid decline. Urinalysis was an indicator of chronic renal disease and the kidney biopsies confirmed progressive irreversible kidney lesions. Evaluation of sequential tests are advocated for the setting of a prognosis. The radiopharmaceutical techniques employed proved to be sensitive indicators of renal dysfunction and a means of evaluating the function of the left and right kidney separately.

A computerised experimental file.

A commercially available program which integrates word processing, spreadsheet, data base, and graph facilities, is used on a microcomputer to write a proforma for an experimental file. The proforma file contains empty forms for all envisaged documentation collected during the experiment's duration. This includes an outline protocol, cost estimate, literature search, detailed protocol, data collection forms, project account, and final report. The program allows linking of spreadsheets, thus for instance enabling date and time information entered on the daily log of events to be automatically transferred to the labour cost form. Introduction of this concept has greatly reduced the amount of time spent on research documentation and the risk of data adulteration through repeated transcription. It has also improved control over research expenses and standardization of trial document formats.

Evaluation of the Venom Ex apparatus in the treatment of Egyptian cobra envenomation. A study in rabbits.

The Venom Ex cutting and suction apparatus for the initial treatment of snakebite was evaluated. Rabbits were injected with radioactive Egyptian cobra venom, and treatment with the Venom Ex followed. The fluid obtained by suction was analysed. All 8 control animals died within 4 hours; Venom Ex treatment resulted in the recovery of 7 out of 8 rabbits, after double the lethal dose of venom, providing treatment was started early. However, if treatment was delayed or if the dose of venom was high, there was a marked increase in the mortality. The amount of venom extracted was insufficient to account for the recovery of the animals. In one group of rabbits trauma was applied to the injection site without lacerating the skin and without removal of venom. About half of these animals recovered. However, this was less efficient than the Venom Ex treatment. Trauma apparently retards absorption of venom and increases survival. The possible reasons for this novel finding are discussed.

Standardization of anaesthesia for radiorenography with primates under laboratory conditions.

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.

The influence of physical and chemical restraint on the physiology of the chacma baboon (Papio ursinus).

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.

Beta-adrenergic blocking drugs and renal function.

A baboon model was used to investigate the effects of atenolol, nadolol, sotalol and labetalol on renal function. The glomerular filtration rate (GFR) and renal blood flow (RBF) were measured, using radionuclides and a gamma camera, before and after 1 week's oral administration of these drugs. All the drugs caused an increase in the GFR, but this reached statistical significance only in the cases of sotalol (P less than 0,025) and labetalol (0,05 less than P less than 0,10). The RBF was not significantly changed, although it decreased in all cases.

The feasibility of a renogram study in dogs with radiopharmaceutical 99mTc-DTPA.

The present study is one of in vivo 99mTc-DTPA renography, successively involving conscious healthy dogs under acepromazine maleate sedation and dogs under the narcotic sodium thiopental. It was found that during the running of the renogram the animal had to be kept completely immobile and that constant infusion narcosis with sodium thiopental produced this immobility without affecting the renograms unduly. However administration of a thiopental bolus did have an adverse effect on the renogram. Sedation with acepromazine maleate significantly increased the time to peak and the excretion phase as presented by the slope. These effects are thought to be due to a decreased blood pressure with concomitant renal bloodpooling and retarded bloodflow. The radioisotope renogram appears to hold great promise for both clinical and research applications. The equipment required for this application however, is so costly that it would only be financially feasible for major centres.

A technique to evaluate bone healing in non-human primates using sequential 99mTc-methylene diphosphonate scintigraphy.

The assessment of bone healing through sequential nuclear medical scintigraphy requires a method of consistent localization of the exact fracture area in each consecutive image as the study progresses. This is difficult when there is surrounding bone activity as in the early stages of trauma, and also if complications should set in. The image profile feature, available from most nuclear medical computer software, facilitates this procedure considerably, as is indicated in the present report on bone healing in baboons. Together with roentgenology and histology a 99mTc-MDP study was in this way successfully done on the healing of long bone fractures experimentally induced in non-human primates. Different surgical implants were used. The results indicate that 99mTc-MDP accurately reflects the physiological activity in bone. The time-activity curves obtained are presently being studied together with extensive histology, bearing possible clinical application in mind.

Attempted transmission of canine ehrlichiosis to the vervet monkey (Cercopithecus pygerythrus).

Blood from a domestic dog infected with Ehrlichia canis was injected into 3 adult vervet monkeys Cercopithecus pygerythrus. The monkeys did not develop any clinical or haematological signs of disease, nor did they seem to be able to harbour the parasite. Furthermore, neither morulae of E. canis nor haematological evidence of ehrlichiosis were seen after these monkeys had been splenectomized. The splenectomized monkeys did, however, develop a severe parasitaemia of their red cells with Entopolypoides macaci. They also showed a transient haematuria, mild inappetence and listlessness.

Detection of abscesses and lymphosarcoma with 111In-deferoxamine mesylate.

Indium-111 deferoxamine was used to delineate induced abscesses or different ages in a baboon, and lymph nodes in a case of canine spontaneous lymphosarcoma, by means of gamma-scintigraphy. Positive results were obtained already 1 hr after administration of the scanning agent, and the lesion-to-background ratio improved progressively with time. The tissue distribution of the radiopharmaceutical was determined in rats, and showed a relatively high isotope retention in the kidneys.

In vivo nuclear techniques in veterinary medicine.

A description is given of the more relevant procedures of diagnostic nuclear medicine as well as of future trends in this field, especially with regard to in vivo research and clinical applications at the biochemical level. The part played by animal models in the past and present is emphasised. The inclusion of a nuclear medicine facility, as equipped and run by the Atomic Energy Board at the H.A. Grové Animal Research Centre is put into perspective.