Le traitement de l’asthme concerne une large population et fait appel très majoritairement à une administration par voie pulmonaire. Cette voie présente certains inconvénients qui pourraient être palliés par le recours à la voie buccale comme envisagé dans cette étude, avec une amélioration attendue de la compliance et de la biodisponibilité. Aussi ce travail a eu pour objectif de développer et caractériser une formulation mucoadhésive thermogélifiante à base de salbutamol. Au regard des contraintes liées à la voie buccale et à la prise en charge du traitement de l’asthme aigu, les principales propriétés pharmacotechniques attendues pour optimiser la biodisponibilité de cette formulation ont été : (i) une gélification optimale autour de 30°C après pulvérisation pour faciliter notamment l’administration ; (ii) des propriétés mécaniques et mucoadhésives importantes pour assurer un maintien de la forme au site d’absorption ; (iii) une cinétique de libération compatible avec le traitement de la phase aigüe de la pathologie. Le choix des excipients a été défini afin d’avoir la plus grande innocuité de la formulation finale. Les travaux expérimentaux ont mis en évidence l’intérêt de certaines techniques innovantes pour la caractérisation de ce type de formulation comme notamment l’étude de libération à l’aide de l’appareil de dissolution à flux continu, la détermination de la cytotoxicité par microscopie holographique digitale et l’évaluation de la mucoadhésion in vitro et in vivo par imagerie. Les résultats ont aussi permis de proposer des modèles mathématiques pour l’interprétation des mécanismes de libération du salbutamol et quantifier l’importance des phénomènes de diffusion et d’érosion. Les conclusions de cette étude sont favorables à la poursuite du développement en vue d’une commercialisation. / The treatment of asthma concerns a large population and generally necessitates an administration by the pulmonary route. This route has some drawbacks which could be overcome by the buccal route, like considered in this study expecting an improvement of the compliance and the bioavailability. The aim of this work was to develop and characterize a thermogelling mucoadhesive formulation containing salbutamol sulfate. The main properties of the formulation were: (i) thermogelation around 30°C to facilitate the administration by spray; (ii) strong mechanical properties and high mucoadhesive strength to maintain the formulation in situ; (iii) drug release kinetics adapted to the treatment. The excipients were selected with regard to the final formulation safety. The experimental work emphasized the great interest of certain techniques in the characterization of this kind of formulation, for example the drug release study using flow through apparatus, the cytotoxicity study using digital holographic microscopy and also the mucoadhesion study by in vivo imaging. The use of mathematical models provided a relevant understanding of drug release mechanisms. The conclusion of this study is favorable to a further development of the project for a future marketing.

Procedimentos analíticos baseados em medidas de quimiluminescência caracterizam-se por apresentar alta sensibilidade, baixos limites de detecção, ampla faixa de resposta linear e instrumentação simples. Uma das principais dificuldades relacionadas a este tipo de medida é maximizar a quantidade de radiação detectada, já que a emissão ocorre em todas as direções, o que dificulta o posicionamento adequado da cela de medida em relação ao sistema de detecção. Uma alternativa consiste na utilização de guias de ondas, que são dispositivos que conduzem a radiação emitida, minimizando perdas durante o transporte, tal como ocorre nos cabos de fibras ópticas. O acoplamento de sistemas de análises em fluxo com detecção por quimiluminescência é bastante conveniente, já que a mistura entre amostras a reagentes precisa ser rápida e altamente reprodutível, além de ser realizada a uma distância muito pequena do sistema de detecção, devido ao curto tempo de vida dos intermediários no estado excitado. Neste trabalho, é apresentada a avaliação de uma cela constituída por um guia de ondas para medidas de quimiluminescência. Estas ferramentas foram aplicadas à determinação de hipoclorito em amostras de líquido de Dakin por quimiluminescência empregando a reação de oxidação do luminol por hipoclorito. Também foi desenvolvido um procedimento analítico para a determinação de salbutamol, explorando a inibição da quimiluminescência da reação de oxidação de luminol por hipoclorito, caracterizando-se como uma alternativa promissora para a quantificação do fármaco. Em ambas as aplicações, os resultados foram concordantes com os obtidos por procedimentos de referência a nível de confiança de 95% / Analytical procedures based on chemiluminescence are characterized by high sensitivity, low detection limits, wide linear response ranges and simple instrumentation. One of the main troubles is to increase the amount of detected radiation, because emission occurs in all directions, making difficulty the positioning of the measurement cell in relation to the detection system. An alternative consists in the use of liquid-core waveguides, devices that constrain the emitted radiation, minimizing losses during the transport, in a similar way to optical fibers. Coupling flow analysis to chemiluminescence is attractive, because sample and reagents mixing needs to be fast, highly reproducible and accomplished close to the detector, in view of the short lifetime of the intermediates in the excited state. In this work, a cell constituted by a liquid-core waveguide was evaluated for chemiluminescence measurements. These tools were applied to the determination of hypochlorite in Dakin solution samples by chemiluminescence exploiting the oxidation of luminol by hypochlorite. An analytical procedure for salbutamol determination, exploiting the inhibition of chemiluminescence of luminol oxidation by hypochlorite, was developed, characterizing as a promising alternative for the quantification of this pharmaceutical substance. In both applications, results were in agreement to those obtained by reference procedures at the 95% confidence level

Background: The effectiveness of inhaled salbutamol in routine care depends particularly on prescribed dosage and applied inhalation technique. To achieve maximum effectiveness and to prevent drug-related problems, prescription and administration need to work in concert. Methods: We performed a controlled intervention pilot study with 4 consecutive groups in a general paediatric unit and assessed problems in salbutamol prescribing and administration. Control group [i]: Routine care without additional support. First intervention group [ii]: We carried out a teaching session for nurses aimed at preventing problems in inhalation technique. Independently from this, a pharmacist counselled physicians on problems in salbutamol prescribing. Second intervention group [iii]: Additionally to the first intervention, physicians received standardised feedback on the inhalation technique. Follow-up group [iv]: Subsequently, without any delay after the second intervention group had been completed, sustainability of the measures was assessed. We performed the chi-square test to calculate the level of significance with p ≤ 0.05 to indicate a statistically significant difference for the primary outcome. As we performed multiple testing, an adjusted p ≤ 0.01 according to Bonferroni correction was considered as significant. Results: We included a total of 225 patients. By counselling the physicians, we reduced the number of patients with problems from 55% to 43% (control [i] vs. first intervention [ii], n.s.). With additional feedback to physicians, this number was further reduced to 25% ([i] vs. [iii], p < 0.001). In the follow-up [iv], the number rose again to 48% (p < 0.01 compared to feedback group). Conclusions: Teaching nurses, counselling physicians, and providing feedback on the quality of inhalation technique effectively reduced problems in salbutamol treatment. However, for success to be sustained, continuous support needs to be provided. Trial registration: German Clinical Trials register: DRKS00006792.

D'après les études fondées sur des questionnaires, la prévalence de l'asthme varie entre 11 et 20 %. Chez les sportifs, celles menées au moyen d'interrogatoires indiquent que la prévalence du bronchospasme induit par l'exercice (BIE) est de l'ordre de 50-74 %. Cette prévalence est ramenée à 11-55 % selon les critères établis lors des tests d'exploration fonctionnelle respiratoire (EFR). L'air froid et sec est un facteur souvent évoqué pour expliquer le BIE. Nous avons étudié la prévalence du BIE chez 25 cyclistes professionnels en climat continental au moyen d'un interrogatoire couplé à des tests pharmacodynamiques et EFR au repos et après exercice. Les résultats ont montré une prévalence de 68 % de sujets symptomatiques et 60 % confirmés asthmatiques. Ces résultats corroborent les études antérieures réalisées sous le même type de climat. Afin d'évaluer un effet éventuel dû au climat, le BIE évalué en climat chaud et humide du Bénin chez 20 basketteurs amateurs par questionnaire et sur la base de tests pharmacodynamiques et EFR a présenté une prévalence de 55% de sujets symptomatiques et 35% confirmés asthmatiques. Nos résultats en climat chaud et humide s'avèrent analogues à ceux observés en climat continental, montrant ainsi que le climat a une influence faible sur le BIE et que l'exercice joue un rôle plus important dans l'initiation et le maintien du BIE.

INTRODUÇÃO: A dosagem ideal de salbutamol através de inaladores dosimetrados para o tratamento da asma aguda na infância não está bem estabelecida. Este estudo visou comparar dois regimes de dosagem de salbutamol via inalador dosimetrado com espaçador em crianças com crises moderadas ou graves de asma. As hipóteses deste estudo foram: I. Pacientes em vigência de crises de sibilância moderadas ou graves necessitam doses de salbutamol maiores que as até recentemente recomendadas pelo Global Initiative for Asthma (GINA). II. Doses maiores de salbutamol são seguras para crianças com idade igual ou superior a dois anos de idade. OBJETIVOS: I. Avaliar a eficácia (principalmente tempo de permanência na sala de emergência e taxas de internação hospitalar) de um regime de doses maiores de salbutamol em comparação com as até recentemente recomendadas pelo GINA. II. Verificar a segurança destas dosagens de salbutamol através do monitoramento de possíveis efeitos colaterais e dos níveis plasmáticos desta droga. MÉTODOS: Este foi um estudo prospectivo, randomizado, duplo-cego e controlado realizado em salas de emergência de três centros na cidade de São Paulo. Foram incluídos pacientes com 2-17 anos de idade com asma aguda moderada a grave (escore PRAM, Pediatric Respiratory Assessment Measure, >= 5). As dosagens de salbutamol via inalador dosimetrado com espaçador administradas durante a primeira hora foram: 6 (até 25 kg) ou 12 jatos ( > 25 kg) no grupo controle e 9 (até 15 kg), 12 ( > 15 a 20 kg), 15 ( > 20 a 25 kg) ou 18 jatos ( > 25 kg) no grupo estudo. Cada jato continha 100 mcg de salbutamol. Os pacientes dos dois grupos receberam corticosteroides e brometo de ipratrópio. Os desfechos principais do estudo foram o tempo de permanência na sala de emergência para os pacientes não internados e a necessidade ou não de internação hospitalar. Os desfechos secundários foram: mudança no volume expiratório forçado no primeiro segundo (VEF1) após uma hora, mudanças no escore PRAM, na oximetria de pulso e na frequência respiratória após uma hora e no tempo final (momento da alta ou internação hospitalar, máximo de quatro horas) e a necessidade de tratamentos adicionais após a primeira hora. Os desfechos de segurança incluíram mudanças nos níveis séricos de potássio, glicose, bicarbonato e pH no tempo final em relação ao tempo inicial, bem como possíveis anormalidades no eletrocardiograma, níveis plasmáticos de salbutamol, mudanças na frequência cardíaca e presença ou ausência de tremores, os dois últimos após uma hora e no tempo final. RESULTADOS: Foram incluídos 119 pacientes com condições basais semelhantes e não foram observadas diferenças significativas entre os grupos no tempo de permanência na sala de emergência (p=0.55) ou nas taxas de internação hospitalar (p=0.48). Não foram observadas diferenças significativas entre os grupos nas mudanças de VEF1 após uma hora, nas mudanças de escore PRAM, na oximetria de pulso e na frequência respiratória após uma hora e no tempo final. Não houve diferenças significativas entre os grupos na necessidade de tratamentos adicionais administrados após a primeira hora. Não foram observadas diferenças significativas nos desfechos de segurança entre os grupos. CONCLUSÕES: O uso de doses maiores de salbutamol administradas através de inalador dosimetrado com espaçador em crianças com asma aguda moderada ou grave não resultou em menor taxa de internação, menor tempo de permanência na sala de emergência ou melhora em outros desfechos de eficácia em comparação com o regime de dosagens até recentemente proposto pelo GINA. Os dois regimes de dosagens mostraram perfis de segurança semelhantes / INTRODUCTION: The ideal dosing of albuterol via metered-dose inhalers for acute childhood asthma is not well established. This study aimed to compare two dosing regimens of albuterol via metered-dose inhaler with spacer in children with moderate to severe asthma attacks. The hypothesis of this study were: I. Patients with moderate to severe asthma attacks would benefit from higher doses of albuterol than those recommended until recently by the Global Initiative for Asthma (GINA). II. Higher doses of albuterol are safe for children two years of age and older. OBJECTIVES: I. To compare the efficacy (mainly length of stay in the emergency room and admission rates) of higher doses of albuterol with those recommended until recently by the GINA. II. To assess the safety of different doses of albuterol by monitoring for possible side effects and measuring drug plasma levels. METHODS: This was a prospective, randomized, controlled, double-blind study conducted in emergency rooms of the three participating centers in the city of São Paulo. We included patients with 2-17 years old with moderate to severe acute asthma (Pediatric Respiratory Assessment Measure, PRAM, score >= 5). Dosages of albuterol via metered-dose inhaler with spacer administered during the first hour included: 6 (up to 25 kg) or 12 puffs ( > 25 kg) in the control group and 9 (up to 15 kg), 12 ( > 15 to 20 kg), 15 ( > 20 to 25 kg) or 18 puffs ( > 25 kg) in the study group. Each puff contained 100 mcg of albuterol. All patients received corticosteroids and ipratropium bromide. Primary outcomes were the length of stay in the emergency room for non-admitted patients, and rate of admission. Secondary outcomes included forced expiratory volume in one second (FEV1) changes following one hour, PRAM score, pulse oximetry and respiratory rate changes following one hour and at the final time (discharge or admission, maximum four hours) and the need for additional therapies after the first hour. Safety outcomes included changes in serum potassium, glucose, bicarbonate and pH at the final time in comparison with the initial time, as well as electrocardiogram abnormalities, plasma albuterol levels, heart rate, and tremors (the last two after one hour and at the final time). RESULTS: We included 119 patients with similar baseline conditions, and no significant differences were observed between groups in the length of stay in the emergency room (p=0.55) or admission rates (p=0.48). No significant differences were observed between groups in FEV1 changes after one hour, and PRAM score, pulse oximetry and respiratory rate changes after one hour and at the final time. There were no significant differences between groups in additional therapies administered after the first hour. No significant differences were observed in safety outcomes between groups. CONCLUSIONS: Higher dosage regimens of albuterol via metered-dose inhaler with spacer for children with moderate to severe acute asthma did not result in lower admission rate, shorter length of stay in the emergency room or improvement in other efficacy outcomes in comparison with those recommended until recently by the GINA. Both dosage regimens showed similar safety profile

INTRODUÇÃO: A dosagem ideal de salbutamol através de inaladores dosimetrados para o tratamento da asma aguda na infância não está bem estabelecida. Este estudo visou comparar dois regimes de dosagem de salbutamol via inalador dosimetrado com espaçador em crianças com crises moderadas ou graves de asma. As hipóteses deste estudo foram: I. Pacientes em vigência de crises de sibilância moderadas ou graves necessitam doses de salbutamol maiores que as até recentemente recomendadas pelo Global Initiative for Asthma (GINA). II. Doses maiores de salbutamol são seguras para crianças com idade igual ou superior a dois anos de idade. OBJETIVOS: I. Avaliar a eficácia (principalmente tempo de permanência na sala de emergência e taxas de internação hospitalar) de um regime de doses maiores de salbutamol em comparação com as até recentemente recomendadas pelo GINA. II. Verificar a segurança destas dosagens de salbutamol através do monitoramento de possíveis efeitos colaterais e dos níveis plasmáticos desta droga. MÉTODOS: Este foi um estudo prospectivo, randomizado, duplo-cego e controlado realizado em salas de emergência de três centros na cidade de São Paulo. Foram incluídos pacientes com 2-17 anos de idade com asma aguda moderada a grave (escore PRAM, Pediatric Respiratory Assessment Measure, >= 5). As dosagens de salbutamol via inalador dosimetrado com espaçador administradas durante a primeira hora foram: 6 (até 25 kg) ou 12 jatos ( > 25 kg) no grupo controle e 9 (até 15 kg), 12 ( > 15 a 20 kg), 15 ( > 20 a 25 kg) ou 18 jatos ( > 25 kg) no grupo estudo. Cada jato continha 100 mcg de salbutamol. Os pacientes dos dois grupos receberam corticosteroides e brometo de ipratrópio. Os desfechos principais do estudo foram o tempo de permanência na sala de emergência para os pacientes não internados e a necessidade ou não de internação hospitalar. Os desfechos secundários foram: mudança no volume expiratório forçado no primeiro segundo (VEF1) após uma hora, mudanças no escore PRAM, na oximetria de pulso e na frequência respiratória após uma hora e no tempo final (momento da alta ou internação hospitalar, máximo de quatro horas) e a necessidade de tratamentos adicionais após a primeira hora. Os desfechos de segurança incluíram mudanças nos níveis séricos de potássio, glicose, bicarbonato e pH no tempo final em relação ao tempo inicial, bem como possíveis anormalidades no eletrocardiograma, níveis plasmáticos de salbutamol, mudanças na frequência cardíaca e presença ou ausência de tremores, os dois últimos após uma hora e no tempo final. RESULTADOS: Foram incluídos 119 pacientes com condições basais semelhantes e não foram observadas diferenças significativas entre os grupos no tempo de permanência na sala de emergência (p=0.55) ou nas taxas de internação hospitalar (p=0.48). Não foram observadas diferenças significativas entre os grupos nas mudanças de VEF1 após uma hora, nas mudanças de escore PRAM, na oximetria de pulso e na frequência respiratória após uma hora e no tempo final. Não houve diferenças significativas entre os grupos na necessidade de tratamentos adicionais administrados após a primeira hora. Não foram observadas diferenças significativas nos desfechos de segurança entre os grupos. CONCLUSÕES: O uso de doses maiores de salbutamol administradas através de inalador dosimetrado com espaçador em crianças com asma aguda moderada ou grave não resultou em menor taxa de internação, menor tempo de permanência na sala de emergência ou melhora em outros desfechos de eficácia em comparação com o regime de dosagens até recentemente proposto pelo GINA. Os dois regimes de dosagens mostraram perfis de segurança semelhantes / INTRODUCTION: The ideal dosing of albuterol via metered-dose inhalers for acute childhood asthma is not well established. This study aimed to compare two dosing regimens of albuterol via metered-dose inhaler with spacer in children with moderate to severe asthma attacks. The hypothesis of this study were: I. Patients with moderate to severe asthma attacks would benefit from higher doses of albuterol than those recommended until recently by the Global Initiative for Asthma (GINA). II. Higher doses of albuterol are safe for children two years of age and older. OBJECTIVES: I. To compare the efficacy (mainly length of stay in the emergency room and admission rates) of higher doses of albuterol with those recommended until recently by the GINA. II. To assess the safety of different doses of albuterol by monitoring for possible side effects and measuring drug plasma levels. METHODS: This was a prospective, randomized, controlled, double-blind study conducted in emergency rooms of the three participating centers in the city of São Paulo. We included patients with 2-17 years old with moderate to severe acute asthma (Pediatric Respiratory Assessment Measure, PRAM, score >= 5). Dosages of albuterol via metered-dose inhaler with spacer administered during the first hour included: 6 (up to 25 kg) or 12 puffs ( > 25 kg) in the control group and 9 (up to 15 kg), 12 ( > 15 to 20 kg), 15 ( > 20 to 25 kg) or 18 puffs ( > 25 kg) in the study group. Each puff contained 100 mcg of albuterol. All patients received corticosteroids and ipratropium bromide. Primary outcomes were the length of stay in the emergency room for non-admitted patients, and rate of admission. Secondary outcomes included forced expiratory volume in one second (FEV1) changes following one hour, PRAM score, pulse oximetry and respiratory rate changes following one hour and at the final time (discharge or admission, maximum four hours) and the need for additional therapies after the first hour. Safety outcomes included changes in serum potassium, glucose, bicarbonate and pH at the final time in comparison with the initial time, as well as electrocardiogram abnormalities, plasma albuterol levels, heart rate, and tremors (the last two after one hour and at the final time). RESULTS: We included 119 patients with similar baseline conditions, and no significant differences were observed between groups in the length of stay in the emergency room (p=0.55) or admission rates (p=0.48). No significant differences were observed between groups in FEV1 changes after one hour, and PRAM score, pulse oximetry and respiratory rate changes after one hour and at the final time. There were no significant differences between groups in additional therapies administered after the first hour. No significant differences were observed in safety outcomes between groups. CONCLUSIONS: Higher dosage regimens of albuterol via metered-dose inhaler with spacer for children with moderate to severe acute asthma did not result in lower admission rate, shorter length of stay in the emergency room or improvement in other efficacy outcomes in comparison with those recommended until recently by the GINA. Both dosage regimens showed similar safety profile

Les recherches sur la fatigue musculaire ont permis de mettre à jour l'implication de différentes altérations tout au long de la chaîne de commande motrice allant du cerveau jusqu'au muscle. Pourtant les mécanismes de régulation centraux et périphériques mis en jeu à l'exercice continuent de faire débat aujourd'hui. Ce travail de thèse a comme objectif d'évaluer de façon originale la fatigue à l'exercice musculaire et de chercher à mieux cerner les mécanismes sous-jacents propres à différentes situations physiologiques ou cliniques. Ce projet a été mené en plusieurs étapes : i) en prenant soin de valider tout d'abord notre outil d'évaluation la stimulation magnétique, en la comparant aux mesures obtenues par stimulation électrique classiquement utilisée pour l'évaluation de la fonction musculaire, ii) puis en évaluant de manière originale la cinétique de développement de la fatigue au cours d'un test à charge constante, cinétique beaucoup moins étudiée dans la littérature que la simple fatigue de fin d'effort, iii) enfin en s'intéressant aux applications cliniques de cet outil en recherchant d'une part les effets possibles de traitements médicamenteux sur la fatigabilité musculaire et d'autre part en étudiant les effets musculaires d'un programme de réentraînement chez des patients mucoviscidosiques. Nous avons ainsi confirmé la validité de l'utilisation de la stimulation magnétique dans l'évaluation de la fonction et de la fatigue neuromusculaires du quadriceps. Nous avons également pu décrire la cinétique de développement de la fatigue du quadriceps au cours d'un effort à charge constante sur ergocycle et démontrer le fait que la fatigue périphérique, plus particulièrement de basse fréquence, apparaissait tôt dès le début de l'exercice et pour l'essentiel dans la première moitié du temps d'exercice, alors que les indices de la fatigue centrale se révélaient en fin d'effort, proche de l'épuisement. Nous n'avons pas démontré d'effets ergogènes provoqués par l'inhalation aigue de ß2-mimétiques, ni d'effet sur le développement de la fatigue neuromusculaire, tant au niveau périphérique que central. L'étude clinique en cours pour laquelle nous avons réalisé une analyse intermédiaire visant à révéler les effets d'un programme d'électrostimulation sur le réentraînement à l'effort chez des patients mucoviscidosiques présentant une dysfonction pulmonaire sévère nous a permis de mesurer des bénéfices obtenus en terme de gain fonctionnel (force au niveau du quadriceps, hypertrophie musculaire) qui ne sont pourtant pas retranscrits en terme d'amélioration de la fonction respiratoire ou de la tolérance à l'effort. Pour conclure, ce travail de thèse a permis de mettre à jour les facteurs déterminants à prendre en compte dans l'évaluation de la fatigue. Les résultats obtenus montrent ainsi l'importance de considérer la cinétique de développement de la fatigue au cours de l'exercice et pas seulement les conséquences visibles à épuisement. D'autre part, ce travail a permis de prouver la validité de la stimulation magnétique, ses limites et les applications possibles au niveau de l'exploration physiologique de la fatigue dans la recherche clinique et le diagnostic précoce de certaines pathologies neuromusculaires.

Exercise Induced Bronchoconstriction (EIB) is common amongst elite athletes. Short-acting β2-agonists represent the first-line treatment of EIB, however; limited data currently exists examining the ergogenic and pharmacokinetic impact of chronic short-acting β2-agonist administration. Furthermore, the ergogenic impact of acute and chronic administration of short-acting β2-agonists in asthmatic individuals is unknown. Whilst the short-acting β2-agonist salbutamol is permitted in and out of competition due to a known pharmacokinetic response, no urinary threshold has been established for the use of the alternative short-acting β2-agonist terbutaline. The purpose of study 1 was to investigate the ergogenic potential of the WADA upper daily limit of 1600 μg·day-1 salbutamol every day for 6 weeks versus placebo, alongside combined resistance and endurance training. Findings highlighted improvements in; 1 repetition maximum (1RM) bench press (Baseline: 65.6 ± 5.4 kg vs. 64.3 ± 4.9 kg – 6 weeks: 70.3 ± 4.9 vs. 72.5 ± 5.4 kg) and leg press (Baseline: 250 ± 26.9 vs. 217.9 ± 19 kg – 6 weeks: 282.5 ± 22.5 vs. 282.8 ± 18.3 kg); vertical jump test (Baseline: 53.5 ± 4.1 vs. 50.4 ± 2.1 cm – 6 weeks: 55 ± 3.5 vs. 52.4 ± 1.7 cm); 3 km running time-trial performance (Baseline: 988.7 ± 68.7 vs. 1040.5 ± 66.3 s – 6 weeks: 947.5 ± 54.9 vs. 1004.3 ± 70.5 s); isokinetic dynamometry (Baseline: 196.1 ± 47.3 vs. 184.6 ± 35.0 n.m. – 6 weeks: 179.5 ± 48.9 vs. 195.2 ± 28.9 n.m.); and body composition (Baseline: 32.1 ± 13.9 vs. 34.9 ± 10.4 mm – 6 weeks: 32.4 ± 14.5 vs. 34.5 ± 10 mm) for both the salbutamol group and the placebo group, respectively, over the 6 week period, with no difference observed between groups, indicating long-term therapeutic use of salbutamol at the WADA upper daily limit has no ergogenic effect. Of note, one participant exceeded the urinary threshold, presenting with an adverse 3 | P a g e analytical finding (AAF) showing that the upper daily limit can lead to AAF’s in susceptible individuals. Athletes who respond poorly to salbutamol treatment are able to apply for the use of the short-acting β2-agonist terbutaline via a therapeutic use exemption (TUE) certificate. Urinary upper limits are unknown for terbutaline and as such it is prohibited at all times without the presentation of a TUE. The purpose of study 2 was to investigate the urinary excretion of terbutaline following single and repeated use of inhaled or oral terbutaline. The aim of the study was to establish a differential distinction between routes of administration which could assist the WADA with regard to anti-doping policy and procedure. Results demonstrated a significant difference in urine concentration of terbutaline between inhaled and oral administration for female Caucasian (670.1 ± 128.3 vs. 361.8 ± 43.8 ng·ml-1; P=0.019; 680.8 ± 91 vs. 369.9 ± 41.9 ng·ml-1; P=0.006), male Afro-Caribbean (343.18 ± 45 vs. 231.3 ± 32.95 ng·ml-1; P=0.044; 389.73 ± 67.4 vs. 212.4 ± 50.3 ng·ml-1; P=0.008) and male Asian (266.4 ± 23.7 vs. 143.3 ± 22 ng·ml-1; P=0.004; 379.5 ± 50.4 vs. 197.5 ± 38.6 ng·ml-1; P=0.000) groups for single (5 mg oral vs. 2 mg inhaled) and repeated (4 x 5 mg oral vs. 8 x 1 mg inhaled) administration trials, respectively. No difference was observed in male Caucasians. High intra- and inter-individual variability between samples meant that a clear distinction between routes of administration could not be established. The study was able to identify an upper urinary threshold following inhaled administration of 1284.3 ng·ml-1 and an upper urinary threshold following oral use of 2376.3 ng·ml-1 which may inform the process of distinguishing between inhaled and oral use. Athletes are permitted to use inhaled terbutaline therapeutically through the TUE process. The purpose of study 3 was to investigate the ergogenic effect of terbutaline at high (2 mg and 4 mg) therapeutic inhaled doses on 3 km running time-trial performance in males and females. The 4 | P a g e study found that inhaled terbutaline, when used at the highest therapeutic dose, has no impact upon 3 km time-trial performance in males (956.3 s vs. 982 s) and females (1249 s vs. 1214.7 s) for placebo vs. 4 mg inhaled terbutaline, respectively. The majority of studies investigating the ergogenic potential of salbutamol have been in healthy individuals. It is not yet understood whether the exercise response differs in asthmatic individuals. The purpose of study 4 was to investigate the use of inhaled salbutamol (400 μg) during a 3 km running time-trial in eucapnic voluntary hyperpnoea positive (EVH+ve) and negative (EVH-ve) individuals, in a low humidity environment. Results demonstrated increased FEV1 in both groups following salbutamol inhalation, which did not translate to improved performance. No performance differences were found between salbutamol and placebo (Sal: 1012.7 ± 50 vs. 962.1 ± 37.5 s – Pla: 1002.4 ± 46.5 vs. 962 ± 28.8 s) in the EVH+ve group vs. the EVH-ve group, respectively. This thesis is the first to investigate the effects of long-term use of salbutamol at the WADA upper daily limit on exercise performance. It is also the first study to establish upper urinary thresholds for terbutaline use, and the effects of therapeutic inhaled terbutaline on exercise performance. The effect of salbutamol on exercise performance at low humidity in asthmatic individuals has also never previously been investigated. Overall, the findings from this thesis support previous research that inhaled β2-agonist use does not provide any ergogenic potential. With β2-agonists being an essential therapy for the treatment of EIB their current position on the WADA List of Prohibited Substances and Methods is appropriate. Further research is warranted to fully elucidate the upper urinary threshold for terbutaline to inform WADA and support the re-introduction of terbutaline as a therapeutic tool in the treatment of EIB in athletes.

Congenital myasthenic syndromes (CMS) are a rare group of heterogeneous disorders, characterised by compromised neuromuscular transmission and symptoms of fatiguable muscle weakness. CMS is caused by mutations in genes that affect the structure and function of the neuromuscular junction (NMJ). In about 20% of CMS cases, patients have mutations in the gene DOK7; the protein product, DOK7, is crucial for maintaining the dense aggregation of acetylcholine receptor (AChR) clusters at the NMJ. DOK7-CMS patients do not respond to treatment with acetylcholinesterase inhibitors which are the first line treatment for most forms of CMS. Instead, a dramatic response to beta-2 adrenergic receptor (ADRB2) agonists, such as salbutamol, is observed. The aim of this project was to investigate the molecular mechanisms that underlie the beneficial effects of ADRB2 agonists. Firstly, NMJ functioning was modelled in vitro by studying AChR clusters formed on cultured C2C12 mouse myotubes in the presence of WT DOK7. Overexpression of mutant DOK7 led to a significant reduction in the number of AChR clusters, explaining the pathogenic effect of the mutation. Importantly, incubation of myotubes with salbutamol increased the number of AChR clusters and their stability. The results provide the first evidence that ADRB2 agonists directly affect proteins located at the NMJ. However, this disease model suffers from limitations. The rest of the thesis focussed on developing alternative cell culture models to explore the AChR clustering pathway. The first model combined optogenetics and fluorescence lifetime microscopy to study the effects of ADRB2 activation on AChR cluster stability in single live cells. The second used CRISPR/Cas9 genome editing tools to directly introduce Dok7 mutations to the genome of C2C12 cells, thereby overcoming some of the drawbacks associated with DOK7 overexpression. Further manipulations of these novel model systems will be used in the future to examine in more detail the molecular events underlying the pathogenic effects of DOK7 mutations and the mechanisms of ADRB2 agonists.

In this study, 14 typical South African feedlot bulls received no beta-adrenergic agonist for the last 30 days of the finishing period (C), 14 received 120 mg R-salbutamol per animal per day for the last 30 days of the finishing period (S30), 13 received 120 mg Rsalbutamol per animal per day for the last 40 days of the finishing period (S40) and the last group of 13 bulls received 60 mg zilpaterol hydrochloride per animal per day for the last 30 days of the finishing period (Zh). All animals were slaughtered after a 3-day withdrawal period. Parameters included weight gain, feed intake, feed conversion rate, warm and cold carcass mass, dressing %, subcutaneous fat thickness, hide yield %, internal carcass fat distribution, % bone, % fat and % muscle of the prime rib-cut, carcass classification code, conformation, compactness, post-mortem carcass pH profiles, cooking loss, shear force, blood urea nitrogen, creatinine and residue levels of the beta-adrenergic agonists. No differences were observed between any of the four treatment groups concerning live feedlot performance. Bulls receiving the S30 and Zh treatments had lower internal carcass fat distribution compared to C bulls (P <0.05). Bulls receiving the S40 treatment had a lower % fat in the prime rib-cut compared to Zh bulls (P <0.05). Carcasses from S30 bulls had higher pH values 24 hours post mortem compared to carcasses from Zh bulls (P <0.01). Meat samples from Zh bulls had higher shear force, which indicates less tender meat, compared to samples from S40 bulls (P <0.05). Change in serum creatinine levels increased only in Zh treated bulls from the start to the end of treatment and may reflect a higher protein turnover in Zh bulls. The results of this study indicate that R-salbutamol has a more pronounced effect on fat metabolism in feedlot bulls compared to zilpaterol hydrochloride, while zilpaterol hydrochloride has a more pronounced effect on protein metabolism. The residue levels in samples of the liver, kidney, muscle and feaces from zilpaterol hydrochloride and R-salbutamol treated bulls were well below acceptable limits. / Dissertation MSc(Agric)--University of Pretoria, 2014 / gm2015 / Animal and Wildlife Sciences / MSc(Agric) / Unrestricted