Patricia van der Merwe

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The stability of some growth promoting agents in cattle urine, under various temperature storing conditions, was investigated. Bovine urine samples obtained from previous excretion studies which contained zeranol, nandrolone and trenbolone respectively, were stored frozen, at room temperature and in direct sunlight. On days 0, 2, 4, 7 and 10, zeranol and(More)
For this study 48 non-infected muscle, lymphatic and visceral bovine tissue samples were collected from an approved red meat abattoir and spiked with 8 x 10(7) cfu/ml of M. bovis. The different spiked samples were subjected to cooking and drying (drying through the process of biltong-making) processes in a controlled laboratory environment. Mycobacterial(More)
An epidemiological study of human poisoning in the Bloemfontein area over a recent 6-year period was performed. Deliberate and accidental poisonings were studied relative to: (i) age of poisoned persons; (ii) sex of poisoned persons; (iii) type of poison involved; and (iv) the time the poisoning occurred. The study also included the number of patients(More)
Stilboestrol tablets (20 x 1 mg) were given to 4 ostriches. Urine was collected over a period of 8 days and stored frozen at-20 degrees C pending analysis. Analyses were performed on a gas chromatograph-mass selective detector for the presence of parent compound and/or metabolites. Diethylstilbestrol and its metabolite, dienestrol, were detected in urine;(More)
The unique configuration and application of the Active Protection System (APS) radar sensor, developed by Reutech Radar Systems, requires the development of a novel multipath interference model. This paper derives a mathematical model for the effects of specular multipath interference (primarily due to ground reflections) on the received signals of a(More)
A high-performance liquid chromatographic method for the simultaneous determination of ephedrine, pseudoephedrine, phenylpropanolamine, norpseudoephedrine and methylephedrine in urine is described. Samples were extracted at basic pH into diethyl ether and then back extracted into a small volume of acetic acid. These extracts were chromatographed on a Phase(More)
BACKGROUND Platelet reactivity assessment is an important tool in both the causal determination of bleeding diathesis as well as in the evaluation of the efficacy of anti-platelet therapy in patients at risk of thrombosis. Sodium citrate is the most widely used anticoagulant for hemostasis investigations. However, some doubt exists over the suitability of(More)
OBJECTIVE To determine whether the intake of contaminated nutritional supplements could cause an athlete to fail a dope test. DESIGN A contaminated nutritional supplement was used, identified in an ongoing study screening over-the-counter nutritional supplements. One capsule of the supplement, containing small amounts of 19-nor-4-androstenedione and(More)
The metabolism of (+)-catechin, 8-benzyl-(+)-catechin, 6-bromo-, 8-bromo- and 6,8-dibromo-(+)-catechin and 6- and 8-carboxymethyl-(+)-catechin by the isolated perfused pig liver resulted in the formation of the corresponding 3'-O-methyl derivatives. The position of O-methylation was determined by alkaline fusion. The bromo derivatives also underwent(More)
Screening procedures utilizing two-dimensional thin-layer chromatography, gas-liquid chromatography and gas chromatography-mass spectrometry were carried out in an attempt to detect stimulant drugs in urine specimens collected from competitors in three major sporting events held during 1983. Drugs classified as forbidden stimulants by the International(More)