Disposée par la loi du 10 septembre 1947, portant statut de la coopération, la coopérative est une « société constituée par plusieurs personnes volontairement réunies en vue de satisfaire à leurs besoins économiques ou sociaux par leur effort commun et la mise en place des moyens nécessaires ». Le précepte « l'union fait la force » est bien souvent avancé par les promoteurs de la coopération, la négociation quant aux conditions d'achat et de vente semblant effectivement quelque peu rééquilibrée face à de puissants cocontractants. Ainsi que le rappelle le rapport d'information enregistré par la présidence du Sénat le 25 juillet 2012 concernant le développement des coopératives, celles-ci prônent la prééminence de la personne sur le capital, et le caractère tout à fait singulier du modèle coopératif qu'il convient de préserver. L'engouement pour la coopération, tout à fait d'actualité avec la loi sur l'économie sociale et solidaire du 31 juillet 2014, qui en fait la promotion, est à la hauteur de l'intérêt que lui portent l'Autorité de la concurrence et la Commission européenne. En effet, dans l’exercice de leurs prérogatives relatives à l’interdiction des ententes entre agents économiques supposés concurrents et des abus de position dominante, ou bien encore au contrôle des opérations de concentration, l'Autorité et la Commission sont susceptibles d’appréhender des sociétés coopératives et de sanctionner certaines pratiques qui fausseraient en réalité le jeu de la concurrence. Comme le souligne le rapport du Sénat précité, le droit européen admet une certaine souplesse quant aux sociétés coopératives, afin de ne pas leur appliquer trop strictement le droit de la concurrence. Néanmoins, l'Autorité de la concurrence a déjà rendu plusieurs décisions et avis lors de fusions de coopératives, ce qui dénote l'aspect litigieux d'un tel sujet et la volonté des agents économiques de certains secteurs de privilégier malgré tout le modèle coopératif. Au cours de ce travail de recherche, il fut nécessaire de vérifier si la « souplesse » avancée par la Commission est une réalité et quelles en sont les raisons et les manifestations. L’utilisation des coopératives dans la grande distribution et le secteur agricole constitue évidemment un premier objet d’étude. Il fut nécessaire d'étudier l'évolution des coopératives, le développement du modèle et de son identité, les techniques contractuelles utilisées pour mieux comprendre et apprécier l’analyse concurrentielle menée par les autorités de concurrence, qu’il s’agisse d’identifier une entente ou un abus de position dominante en leur sein. Plus généralement, il fut question d'appréhender l'impact des règles du droit de la concurrence et du marché, européen et français, sur ces groupements particuliers que sont les sociétés coopératives pour mesurer si leur spécificité entraîne ou devrait justifier un traitement particulier et comment leur identité a muté en conséquence. / Le résumé en anglais n'a pas été communiqué par l'auteur.

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Class of 2005 Abstract / Objectives: Doses of vancomycin are frequently estimated using various predictor formulas aiming for trough concentrations between 5 and 15 mg/L and peak concentrations between 25 and 40 mg/L.1 There is however, some controversy about the relationship between vancomycin concentrations and therapeutic response. This project compares the ability of several methods to estimate serum concentrations of vancomycin. Methods: This project was a retrospective look at 243 patient records, the patients were given vancomycin and later had at least one concentration measured. Data collected while the patient was being treated was used in the nine predictor models to determine which model would best predict actual concentrations. The methods compared were Moellering, Matzke, Lake-Peterson, Rodvold, Abbott, Birt, Burton, Ambrose, and Bauer. Results: There were 188 patients included in the analysis, 97 males and 91 women. The method with the least bias (+ 1.0) was the Rodvold method using the actual body weight. None of the models were very precise, with most around 10 (high of 12.83, and a low of 9.35). The r- values for all the models were also low, none of the models had an r- value greater than 0.5. The Lake-Peterson method predicted within 20% and 50% the most often; the Ambrose method the least often within 50%, and both Ambrose and Bauer the least often within 20%. The Lake-Peterson method predicted concentrations within plus or minus 2.5 and 5.0 mg/L of measured concentrations most frequently. The Ambrose method predicted concentrations within plus or minus 2.5 mg/L of measured the least often; Burton and Rodvold the least often within 5.0 mg/L of measured. Implications: With the best model only accurate (defined as ± 20%) less than 25 percent of the time, there is too much error to make a good decision on dose and interval without the feedback of measured serum concentrations. The models may be a good starting point as which dose and interval to choose, but they are not a substitute for measuring steady state concentrations.

Minocycline (MC) and Doxycycline (DC) are used worldwide as locally applied adjuncts in the treatment of periodontal diseases. As a group the tetracyclines are well known for their advantageous properties. There is however possible cytotoxicity towards cells in the area of application. This study determined the minimum cytocidal concentration of MC and DC on the growth and proliferation of Human Periodontal Ligament Fibroblasts (HPLF) in vitro. This was facilitated by growing cells (PDL1 and PDL2) in the presence of MC and DC in media in 96 tissue wells starting at a concentration of 1400 µg.ml-1 (100%). Serial dilutions of the MC and DC at 10% increments were investigated in order to detect significant HPLF cell growth inhibition. The significant LD50 was further determined at one percent increments in order to arrive at a specific percentage value. The results were read as LD50 values from growth concentration curves. The LD50 of MC on PDL1 and PDL2 after one hour exposure was 686 µg.ml-1 and 896 µg.ml-1 respectively while for DC it was 252 µg.ml-1 and 546 µg.ml-1. The LD50 of MC on PDL1 and PDL2 after 24 hour exposure was 196 µg.ml-1 and 266 µg.ml-1 respectively while for DC it was 252 µg.ml-1 for both. The LD50 of MC on PDL1 and PDL2 after 48 hour exposure was 252 µg.ml-1 and 182 µg.ml-1 respectively while for DC it was 154 µg.ml-1 and 168 µg.ml-1. Based upon the LD50 values this study found that DC is more cytotoxic than MC and linked to this, the two cell lines reacted slightly differently. The concentrations MC and DC tested in this study did however not influence growth of HPLF significantly. / Dissertation (MChD)--University of Pretoria, 2010. / Oral Pathology and Oral Biology / unrestricted

Faculty of Health Sciences School of Medical 0212352d dlabuschagne@anglogoldashanti.com / Dust has been recognized as the most serious occupational health hazard across the South African Mining Industry. During 1998 more than 5600 mineworkers were certified with silicosis, a silica related lung disease. The objective of this research project is to describe the trend in respirable dust concentrations in four underground gold mines for the period 1999 to 2002. The mines under discussion are situated in the Klerksdorp area and they were selected because they are a typical representation of deep underground gold mines. Typical gold mines use the same method of ventilation distribution and have similar dust sources e.g. breaking, transporting and tipping of rock. They are all situated in the same geographical area and all make use of conventional mining methods. A total of 4645 previously collected personal respirable dust samples were analysed for this research report making use of a central laboratory situated in the Klerksdorp area. The respirable dust samples were collected by the Occupational Hygienists appointed on the mines for control purposes over the years 1999 to 2002. The arithmetic mean respirable dust concentrations for the four mines in discussion was 0,39mg/m3 in 1999, 0,33mg/m3 in 2000, 0,30mg/m3 in 2001 and 0,31mg/m3 in 2002 against the mine’s internal target of 0,4mg/m3. The report shows a statistically significant downward trend in the proportion of measurements below 0,4mg/m3 for mines 1, 2 and 3. The percentage of respirable dust samples above the internal target of 0,4mg/m3 was 6,78% in 1999, 6,15% in 2000, 4,71% in 2001 and 4,38% in 2002. Although there is a general downwards trend in the percentage of samples above the target, there is an increase in the number of samples above the target. In 1999, 202 samples were above, 310 in 2000, 402 in 2001 and 361 in 2002. The key limitation to the project is the integrity of the data. The major limitations identified include non compliance with the sampling strategy. There is no guarantee that the instrumentations were worn on the body for the whole shift or whether any tampering of the gravimetric pumps took place. The sampling strategy measures all occupations, but all occupations do not receive the same type and amount of exposure, making it impossible to allocate exposure to a certain workplace. Samples could get affected during storage and transport. The most recent audits on the mine’s central laboratory show 100% compliance with the required standards. The mines under study are well in line with the DME requirements on the guidelines for a measurement strategy of airborne pollutants. The gravimetric sampling strategy includes the scheduling of samples managed by the electronic database system. Although the report indicates that the results are pointing in the right direction, the integrity of the data should be tested continuously. Supervision of the pump wearers is of great concern and training of these wearers is essential for explaining the purpose of the personal monitoring strategy. There is a scarcity of published information on respirable dust concentrations in underground gold mines and further research is required.

MMed, Chemical Pathology, Faculty of Health Sciences, University of the Witwatersrand / Introduction The 516G>T polymorphism in exon 4 of the CYP2B6 gene has been linked to increased plasma Efavirenz (EFV) levels. EFV levels can predict therapeutic efficacy and are related to the likelihood of developing adverse central nervous system (CNS) effects. The aims of this study were to a) determine the presence of the 516G>T and other possible CYP2B6 exon 4 polymorphisms in a South African group of HIV-infected individuals and b) to investigate the relationship between the EFV plasma concentrations, the CYP2B6 516G>T polymorphism and the occurrence of CNS related side effects in this group of patients. Methods Data from 80 patients are presented. Genetic polymorphisms in exon 4 of the CYP2B6 gene were identified using PCR amplification of this region followed by sequencing of the amplification products. EFV levels were analysed by Ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). Assessment of the presence of CNS related side effects following EFV initiation were elicited with the use of a questionnaire together with physical examination. Results Plasma EFV concentrations displayed high inter-individual variability amongst subjects with levels ranging from 94 μg /l to 23227 μg/l. 23 % of patients were TT homozygous for the 516G>T polymorphism. These patients had significantly higher EFV levels vs. those with the wild (GG) genotype (p <0.05). Those who experienced no side effects had significantly lower EFV plasma concentrations vs. the group which experienced the most severe side effects (p< 0.05). iv Conclusion The significant association between the 516G>T polymorphism and plasma EFV concentrations has been demonstrated in a South African cohort. A rapid and sensitive method for the measurement of plasma EFV was developed and validated.