Biomedical subjects

M Maree

Publications and source records attributed to M Maree.

29 records · Page 2Linked to original sources

PubMed1987

The sensitivity of radionuclide and thermodilution techniques to detect cardiac dysfunction in the baboon model during prolonged anaesthesia.

This study was undertaken to evaluate the fluctuations of cardiac parameters in a baboon model during pentobarbitone anaesthesia which will serve as a baseline control for shock studies. Thermodilution and radionuclide methods were used to determine cardiac parameters. Radionuclide studies were repeated without any cardiac catheters to assess the effect of these on cardiac performance. The results represent baseline fluctuations in cardiac parameters against which cardiac dysfunction can be diagnosed in shock studies. The results also indicate that cardiac catheterisation does not affect cardiac performance significantly.

Anesthesia, Intravenous↗

PubMed1987

Comparative radionuclide and thermodilution determinations of cardiac output and stroke volume in the baboon (Papio ursinus).

Thermodilution cardiac output determinations and multigated equilibrium blood-pool scintigraphy were performed in ten healthy chacma baboons (Papio ursinus). The correlation was moderately good between both the radionuclide and thermodilution stroke volume (r = 0.58, SEE = 3 ml; SVth = 0.78SVr + 15.6 ml) as well as the cardiac output (r = 0.72, SEE = 0.2 liter/min; COth = 0.56 Cor + 2.1 liter/min). The attenuation depth dr as determined by radionuclide techniques was found to correlate well with the radiologically determined values dx (r = 0.8, SEE = 0.4 cm; dx = 0.87dr + 0.72 cm) which validated the depth values used in the calculations.

Animals↗

PubMed1986

Entrapment of platelets in the penis during and after erection.

Because of the development of hypercoagulability and the deposition of fibrin in the penis during erection a study of the possible role of platelets in this process was undertaken. Platelet response was studied in 9 adult chacma baboons (Papio ursinus) using autologous in vitro indium-111-labelled platelets and sequential scintigraphy of the penis during erection. The blood pooling pattern was obtained using in vivo technetium-99m-labelled red cells in a similar investigation. A statistically significant retention of platelets occurred during and after erection, which could not be attributed to blood pooling (P less than 0,05). Entrapment of platelets could lead to enhanced activity and activation, and might play a significant role in hypercoagulability and fibrin deposition during erection. Therefore platelets could be an important factor in the pathogenesis of ageing impotence.

Animals↗

PubMed1986

A comparison of 111In-labelled polymer beads and 99mTc-Sn-colloid as solid food and semi-solid food tracers for scintigraphic gastric emptying studies.

In order to establish the efficacy of labelling a solid meal and a semi-solid meal with either 111In-labelled polymer beads or 99mTc-tin colloid beagle dogs were fed variously labelled meals of different consistencies and then monitored by scintigraphy for gastric motility patterns. The labelling with each tracer was either performed by thoroughly mixing it into the food before cooking, or alternatively by surface labelling after the food had been cooked. For the 99mTc-Sn-colloid tracer no difference was found in the measured gastric emptying times resulting from either pre-cooking labelling or surface labelling of the meals. Cooking the tracer together with the ingredients does however seem to promote a firm entrapment of the 111In-polymer beads into a solid protein, and in this manner the 111In-labelled resin appears to be a reliable solid food tracer. Surface labelling with 111In-polymer beads of a solid meal with a smooth texture fails totally and the tracer empties with the liquid phase.

Animals↗

PubMed1986

Experimental radionuclide ventriculography and the baboon (Papio ursinus) model: imaging projection of the heart and blood pool labelling.

The chacma baboon (Papio ursinus) presents a suitable animal model for the evaluation of interpretation problems of data from radionuclide ventriculography. However, the procedure has to be standardized: it is important to so view the heart as to ensure optimal ventricular separation and minimal ventricle-atrium overlap. Also necessary is efficient labelling of the blood pool for good cardiac images and prolonged experimentation. This report concerns an evaluation of different cardiac viewing projections and labelling procedures, and concludes with a preferred method.

Animals↗

PubMed1985

The detection and evaluation of drug-induced changes in the gastrointestinal motility of beagle dogs using a 111In-labelled resin mixed into a standard meal as tracer.

An investigation was performed to establish the usefulness of 111In-labelled polymer beads mixed into a standard meal as a tracer of gastrointestinal(GI)-motility changes due to the influence of various drugs. The labelled polymer beads were well mixed into the food, which was then fed to healthy beagle dogs undergoing drug therapy. GI motility was monitored using a gamma camera and data processor. The results were compared to those obtained from corresponding placebo studies on the same dogs. A significant acceleration of gastric emptying and colon transit was noted under the influence of a gastric and intestinal prokinetic coded R51619. No influence on GI motility could, however, be detected after the administration of a calcium-blocking agent to the dogs.

Animal Feed↗

PubMed1984

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.

Acid-Base Equilibrium↗

PubMed1984

The use of autologous 111In-labelled platelets and scintigraphy to illustrate enhanced platelet activity during erection in the chacma baboon.

The demonstration of thrombelastographic hypercoagulability in the penile blood during erection, and the accompanying deposition of fibrin onto the endothelial layer of the deep penile artery and trabecular surface inspired this investigation of the possible role that platelets might play in the process. The bloodpooling pattern in the penis during and after erection from electro-stimulation was studied in 9 male adult baboons (Papio ursinus) using in vivo 99mTc-labelled red blood cells and scintigraphy. Platelet activity was similarly investigated after administering autologous 111In-labelled platelets to the baboons. The results indicate an enhanced platelet concentration with respect to bloodpooling during erection, and an entrapment of platelets after erection.

Animals↗

PubMed1981

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.

Abscess↗

PubMed1980

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.

Animals↗

PubMedDate not supplied

Prostaglandin E1 and papaverine: a comparative study on the ability to increase the penile bloodpool as measured by the 99mTc-penogram in the baboon model.

The evaluation of arterial blood supply and venous drainage of the penis is essential in assessing the impotent male. The vaso-active drugs prostaglandin E1 and papaverine, as intracavernous injections, cause penile erections in humans by influencing the arterial blood supply and venous drainage. These drugs were used in the normal baboon and in vascular compromised baboons using a 99mTc-penogram to quantify the vascular status of the penis. Ligation of the A. Iliaca Interna was performed to change the penile blood supply, thus compromising the vascular supply. It was observed that pre- and post-operatively, the increase in the penile bloodpool was more dramatic although not significantly so (P less than 0.05), but more variable after papaverine than with prostaglandin E1. The effect was even more enhanced (P less than 0.05) in the vascular compromised baboons so that the occurrence of priapism after papaverine can speculatively not be excluded. Also the more consistent vasoactive response after prostaglandin E1 seems to establish it as the superior intracavernous injectable agent.

Alprostadil↗