Orientador: Ellen Cristini de Freitas / Banca: Marcelo Papoti / Banca: Julio Sérgio Marchini / Resumo: A taurina é um aminoácido não essencial que atua principalmente no músculo esquelético evitando lesões musculares e auxiliando no tônus muscular. Visto a importância de um aporte nutricional adequado considerando calorias, carboidratos e proteínas, a fim de maximizar a recuperação após o treino e minimizar o risco de lesões musculares, a utilização de taurina seria uma alternativa para prevenir a inflamação e danos musculares, favorecer o processo de síntese proteica e reparo muscular e consequentemente melhorar a qualidade do treino sequencial dos triatletas. OBJETIVO: Analisar os efeitos de 8 semanas de suplementação de taurina e achocolatado sobre os marcadores de lesão muscular, resposta inflamatória e a capacidade aeróbia em triatletas. MÉTODOS: Foi realizado um estudo duplo cego, crossover, randomizado o qual contou com a participação de 9 triatletas da categoria de longa distância, do sexo masculino, com idade entre 25 a 35 anos. Foi realizada a suplementação de 3 gramas de taurina (TAU) ou placebo (PLA) associado a 400 ml de achocolatado de baixo de teor de gordura, durante o período de 8 semanas. Foram coletadas amostras de sangue antes (Pré) e após (Pós) cada período de suplementação para quantificação de marcadores de lesão muscular como lactato desidrogenase (LDH) e creatina quinase (CK), e também de marcadores inflamatórios como fatores de necrose tumoral-alfa (TNF-alfa) e interleucina-6 (IL-6). O desempenho físico dos triatletas foi avaliado por teste de exaustão em esteira. RESULTADOS: Foi constatado um aumento significativo nas concentrações de CK após a suplementação taurina (p=0,01). Entretanto as concentrações de LDH não apresentaram diferença significativa após as suplementações realizadas (TAU 16 Pré; 270,13±141,3 U.L-1 e... / Abstract: Taurine is an essential amino acid that acts primarily in skeletal muscle preventing muscle damage and improving muscle tone. Given the importance of an adequate nutritional supply considering calories, carbohydrates and proteins in order to maximize recovery after training and to minimize the risk of muscle damage, the use of taurine would be an alternative to prevent the inflammation and muscle damage, favor the process of protein synthesis and muscle repair and consequently improve the quality of triathlon training. In order to verify the effects of 8 weeks of taurine and chocolate milk supplementation, markers of muscle damage and inflammatory response, and aerobic capacity were quantified in triathletes. METHODS: A double-blind, crossover, randomized study was conducted with 9 male long distance triathletes, aged 25-35 years. Supplementation of 3 g of taurine was performed (TAU) or placebo (PLA) associated with 400 ml low fat chocolate milk during an 8-week period. Blood samples were collected before (Pre) and after (Post) each supplementation period for quantification of markers of muscle damage: Lactate dehydrogenase (LDH), creatine kinase (CK), inflammatory markers: tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6), the physical performance of triathletes was evaluated by treadmill test until exhaustion. RESULTS: It was observed a significant increase in CK levels after TAU supplementation (p = 0.01). However, LDH concentrations did not differ significantly after the supplementations performed (TAU Pre; 270.13 ± 141.3 UL-1 and Post 350 ± 186 UL-1 ); (PLA Pre 196.07 ± 78.1 UL-1 and Post 230.2 ± 98.5 UL-1 ), and there were no changes in physical performance parameters; Anaerobic Threshold (TAU Pré 11,05±0,7 km/h e Pós 11,12±0,94 km/h); (PLA Pré 11,1±0,8 km/h e Pós 18 11,05±1,2), ... / Mestre

Thyroid hormones (TH) exert their multitude of effects on body development, growth and metabolism largely via transcriptional regulatory pathways. TH-induced transcription is controlled by receptors present in the cell nucleus, therefore extracellular TH must first cross the plasma membrane to gain entry into the cell. The exact mechanisms of TH transport across the plasma membrane are only beginning to be clarified, but it is likely that transport may be an important control step for the effects of TH on transcription. Members of the recently cloned organic anion transporting polypeptide (OATP) family have been shown to transport TH. Inhibitor studies indicate that both the aromatic amino acid System T-type transporter, and the broad scope neutral amino acid transporter System L are mediators of TH uptake into various cell types. However cloned amino acid transporters have not been studied to demonstrate directly whether they can accept TH as substrates.

Antiretroviral treatment pre-exposure prophylaxis (PrEP) is an effective daily prevention medicine to reduce risks of HIV infections in high-risk populations. The current study examined PrEP uptake among gay men using the integrative model of behavioral prediction (IMBP) as the theoretical framework. Briefly, the IMBP states that attitude, norms, and behavioral control predict intention, which then predicts behavior. The intention-behavior relationship is moderated by actual control variables: skills and environmental constraints. To examine how IMBP variables affect PrEP uptake among gay men, I first conducted formative elicitation interviews with gay men; then I used the results from the interviews to construct the main survey. Then, the project recruited 500 gay men to participate in the survey, half of whom were PrEP takers and half of whom were not. The results of path modeling showed that attitudes and norms predicted behavioral intention, and intention predicted PrEP uptake among gay men. Results of moderation analyses testing the influence of skills and environmental constraints showed that HIV knowledge, lack of access to a doctor(s), and lack of health care system knowledge were significant moderators between intention and PrEP uptake. The practical implications, theoretical contributions, and empirical advancements were discussed.

To enter cells, the filovirus, ebolavirus (EBOV), must bind to target cells and internalize into an endocytic vesicle. The properties surrounding filoviral entry into permissive cells remain poorly studied. To date, the kinetics associated with filoviral-glycoprotein (GP)-mediated entry have never been investigated past 6 hours. Our initial entry studies with filoviral-GP pseudotyped retrovirions at 37˚C indicated that virions entered permissive cells with a half time (T50) of ~8 hours. We found that 10 to 20% of retroviral based virions bound to cells in over a one hour period at 4˚C suggesting that virion binding was relatively inefficient. Surprisingly, we also observed that less than half of the retroviral based pseudovirions pre-bound to the cell surface were internalized by 7 hours at 37˚C indicating that virion internalization was a slow process. Consistent with slow internalization of retroviral particles, we observed that, while virus entry lost sensitivity to ammonium chloride treatment with time, 50% of the virions remained sensitive to low pH neutralization for at least 7 hours. These slow entry kinetics for filoviruses have not been appreciated thus far, and could have significant implications in the timing and types of treatments that could be administered to filoviral infected individuals. We also determined the impact of specific carbohydrate linkages on host cell plasma membrane proteins involved in filoviral entry, by using a series of Chinese hamster ovary (CHO) cell lines deficient in one or more enzymes required for N- and O- linked glycosylation. The LdlD CHO cell line that expresses normal surface N-linked glycans but has abbreviated O-linked surface glycans showed a 50% reduction in transduction by both Zaire (ZEBOV) and Lake Victoria MARV-GP pseudotyped particles as compared to the control wild type parental CHO cell line (Pro5). Use of the novel O-linked inhibitor drug 1-68A allowed us to confirm the necessity of O-linked glycans in efficient ZEBOV entry into additional permissive cells types. Interestingly, loss of terminal sialic acids (Lec2 cells) or galactose (Lec8 cells) on both N- and O- linked sugars resulted in a 2-fold enhancement of filoviral GP mediated entry compared to control. However, Lec1 cells that have wild type O-linked glycans but highly abbreviated N-linked glycans had similar levels of transduction to control Pro5 cells. Further studies indicated that binding of ZEBOV pseudovirions to Pro5 and all mutant CHO cells was equal, indicating that a post-binding defect or enhancement in ZEBOV internalization may be occurring. These data identify the importance of host cell O-linked glycosylation during the initial steps of filovirus infection. While the receptor(s) used by filoviruses for productive binding and entry into cells remains to be identified, several proteins have been shown to enhance filoviral entry into cells. Axl, a plasma membrane associated Tyro3/Axl/Mer (TAM) family member, is necessary for optimal ZEBOV-GP-dependent entry into some permissive cells, but not others. To date, the precise role of Axl in virion entry is unknown. Through the use of biochemical inhibitors, RNAi, and dominant-negative constructs, we set out to characterize entry pathways used for ZEBOV uptake in cells that require Axl for optimal transduction (Axl-dependent cells) and to define the role of Axl in these processes. We demonstrate that ZEBOV-GP-dependent entry into Axl-dependent cells occurs through multiple pathways including both clathrin-dependent and caveolae/lipid raft-mediated endocytosis. Surprisingly, both dynamin-dependent and -independent fluid-phase uptake (FPU) pathways mediated ZEBOV-GP entry into the Axl-dependent cells as well. Reduction of Axl expression by RNAi treatment resulted in abrogation of ZEBOV entry by FPU-dependent pathways, but had no effect on receptor-mediated endocytosis mechanisms. Our findings demonstrate for the first time that Axl enhances FPU, thereby increasing productive ZEBOV entry, and providing insight into the mechanisms surrounding filoviral entry.

Sugar (primarily sucrose) has been a part of the daily diet for literally hundreds of years, but research is now suggesting that sugar intake can be detrimental to our health. In particular, excessive consumption of simple sugars with high glycemic index (GI) values have been shown to cause overeating and weight gain. As well, elevated postprandial hyperglycemia can result after consuming sugars and this has been linked to disease formation and progression, the development of advanced glycation endproducts, inflammation and increased mortality rates. Honey has been recognised as having a number of beneficial health properties, including slower uptake into the bloodstream, a pharmacological action of reducing blood glucose levels and a high level of bioavailable antioxidants, all of which may mean that honey could be less harmful to health than sucrose in the diet. This study was therefore designed to investigate the health benefits of honey in the diet as a replacement for sucrose, using small animal studies. As well, because of the interest in using honey as a replacement for sucrose in sweetened dairy foods, a small number of in vitro investigations were carried out to determine whether honey could retain its bioactive properties when combined with milk/dairy products. Using the in vitro studies, it was shown that the combination of milk with honey had no effect on either the antibacterial or antioxidant capabilities of honey. During the animal feeding studies a number of significant findings were observed. In the earlier work it was shown that honey had a significant effect on protein metabolism when fed for 14 days at a level of 600 g/kg diet (comprising 480 g sugars and 120 g water) compared with animals fed an equivalent amount of sucrose. In this study, honey-fed rats exhibited significantly lower weight gains (p less than 0.001), food intake (p less than 0.05) and nitrogen intakes (p less than 0.05) and significantly higher faecal nitrogen outputs (p less than 0.05) compared with sucrose-fed rats. Animals fed a diet consisting of 480 g/kg of mixed sugars as in honey generally exhibited protein metabolism parameters that were comparable to those of the sucrose-fed rats, suggesting that the effects of honey on protein metabolism were not due solely to its distinctive sugar composition. Furthermore, in another study that specifically investigated the effects of honey on weight regulation, honey (100 g/kg diet) resulted in significantly reduced weight gain after 6 weeks (p less than 0.01) compared with animals fed the same amount of sugars as sucrose, although food intake was not reduced in this study. Percentage weight gains were shown to be comparable between honey-fed rats and those fed a sugar-free diet, suggesting that differences in glycemic control may be partly responsible for the results seen. Fasting lipid profiles and blood glucose levels were also measured in this study, but no significant differences were observed between diet groups. During long-term (12 months) feeding weight gain was again significantly reduced in rats fed honey (p less than 0.05) and a sugar-free diet (p less than 0.01) compared with those fed sucrose, the weights of honey-fed rats and those fed the sugar-free diet being comparable at the end of the study. In addition, blood glucose levels were significantly lower (p less than 0.001), and HDL-cholesterol levels significantly higher (p less than 0.05) in animals fed honey compared with those fed sucrose after 52 weeks, but no differences in these parameters were observed between rats fed sucrose and a sugar-free diet. No other significant differences in lipid profiles were observed. Immunity measures were improved after feeding honey or sucrose for 52 weeks, animals in both of these diet groups having significantly higher levels of neutrophil phagocytosis compared with those fed the sugar-free diet (both p less than 0.0001). In addition, the percentage of leukocytes that were lymphocytes was significantly higher in honey-fed rats at the end of the study. Furthermore, levels of oxidative damage in aortic collagen were significantly reduced in rats fed honey or the sugar-free diet (both p less than 0.05) compared with those fed sucrose after 52 weeks. Full body DEXA scans were also undertaken in this 12-month study to assess body fat levels and bone mineral composition and density, although they revealed few statistically significant differences. Percentage body fat levels were shown to be nearly 10% lower in honey-fed rats compared with sucrose-fed animals at the end of the study (p less than 0.05), but no other significant differences between diet groups were observed. With one exception, no differences in bone mineral composition or bone mineral density were observed between the three diet groups after 52 weeks. This data agreed with the results generated from two earlier studies that showed that feeding honey short-term (for 6-8 weeks) to rats that were either calcium-deficient or fed a low calcium diet had no effect on bone calcium levels, bone mineral content, bone mineral density or bone breaking parameters. Lastly, long-term feeding of honey to rats had a number of statistically significant effects on anxiety and cognitive performance when assessed using animal maze tasks. Anxiety-like behaviour was significantly reduced in honey-fed rats overall compared with those fed sucrose (p = 0.056) or a sugar free diet (p less than 0.05). Spatial memory was also better in honey fed-rats throughout the 12 month study, these animals not displaying the same degree of age-related spatial memory loss seen in the other two diet groups. No significant differences in recognition memory or learning capability were observed between diet groups after 52 weeks. In conclusion, both short-term and long-term feeding of honey result in a number of health benefits compared with eating similar amounts of sucrose. These include less weight gain, improved immunity, reduced levels of oxidative damage and improved cognitive performance.. These effects of honey are likely to occur through a number of different processes, although the presence of high concentrations of antioxidants and other minor components in honey are likely to be important contributors. Honey may therefore help to improve human heath if it is used as an alternative to sucrose in foods and beverages, although feeding studies in humans are required to assess its efficacy. In addition, more animal studies are needed to assess which features of honey (e.g. fructose content, antioxidant content and bioactivities) are required to achieve optimal effects, and to determine what impact heating and food processing may have on the beneficial health effects of honey.

Priming exercise, or the ‘warm-up’, is an accepted practice prior to exercise participation, physical training or sporting competition. Traditionally, low intensity exercise has been used prior to both short- and long-duration events in an effort to prepare the athlete, but not fatigue them. Recently, however, a more scientific approach to priming exercise has been considered important, with some research suggesting that a high intensity intermittent priming strategy may be optimal. However, given the paucity of performance focussed ‘warm-up’ studies, and that existing data regarding high-intensity priming strategies is inconclusive, the aim of this thesis was to determine the effects of three high-intensity intermittent priming strategies on physiological responses and subsequent 3km laboratory time-trial (TT) performance. Ten well-conditioned endurance-trained male cyclists (mean ± SD: age, 28.3 ± 8.4 yr, body mass, 81.8 ± 11.6 kg, stature, 1.8 ± 0.1 m, O2peak, 4.6 ± 0.5 L•min−1) were recruited for this study. After an initial incremental exercise test to exhaustion, participants completed four 3km time trials (TT) on four separate occasions, each preceded by a different priming strategy. These included a ‘self-selected’ (control) condition, and three high-intensity intermittent priming strategies of varying intensity (100% and 150% of the power at O2peak, and all-out) and fixed duration (15 minutes), each in predetermined random order. Five minutes passive rest separated each priming exercise condition from the experimental 3km-TT. Oxygen uptake ( O2) and heart rate (HR) were measured continuously, while blood lactate concentration ([BLa]) and core temperature (TC) were recorded at rest, post-priming exercise, and immediately prior to and following the 3km-TT. In an attempt to provide a mechanistic explanation for changes in performance, O2 kinetic variables were determined from the O2 data. Performance was quantified as a mean power (Wmean) and total time taken to complete the 3km-TT. Mean power output and time taken for each 500m segment of the 3km-TT were also calculated. Results demonstrated that the athletes self-chosen priming condition (378.6 ± 44.0 W) resulted in Wmean that was slightly greater than both the lowest (376.3 ± 44.9 W; 0.7%; p = 0.57) and moderate (373.9 ± 47.8 W; 1.5%, p = 0.30) intensity intermittent priming condition, but significantly greater than the ‘all-out’ intermittent sprint priming condition (357.4 ± 44.5 W; 5.8%, p = 0.0033). Similar differences were observed for time. While differences existed in the O2 deficit (however, mainly non-significant), these differences did not provide clear explanations for the differences in performance, with the moderate priming condition displaying a significantly reduced O2 deficit (59.4 ± 15.6 L, p < 0.05), despite the non-significant change in Wmean, compared to the self-chosen priming condition (73.3 ± 18.6 L). Additionally no significant differences were observed in either the time constant or the mean response time of O2. Significant findings with regard to HR, [BLa] and TC were observed, but consistent with O2 kinetic variables, they were not related to, nor explain performance changes. In conclusion, regardless of intensity, different high-intensity intermittent priming exercise did not improve 3km-TT performance more than the control condition (self-chosen). A priming strategy that is overly intense was detrimental to subsequent cycling performance. The observed finding that a self-chosen priming strategy resulted in a comparable performance suggests that athletes are able to self-select (consciously or sub-consciously) a ‘warm-up’ that is of appropriate intensity/duration. Further work utilising the priming strategies from the current study with events of shorter duration is required to further clarify how priming strategies of this nature may affect track cycling performance.

PowerCranks(tm) are claimed to increase economy of motion and cycling efficiency by reducing the muscular recruitment patterns that contribute to the resistive forces occurring during the recovery phase of the pedal stroke. However, scientific research examining the efficacy of training with PowerCranks(tm) is lacking. Therefore, the purpose of this study was to determine if five weeks of training with PowerCranks(tm) improves economy of motion (EOM), gross efficiency (GE), oxygen uptake (V.O2) and muscle activation patterns in trained cyclists. Sixteen trained cyclists were matched and paired into either a PowerCranks(tm) (PC) or Normal Cranks (NC) training group. Prior to training, all subjects completed a graded exercise test (GXT) using normal bicycle cranks. Additionally, on a separate day the PC group performed a modified GXT using PowerCranks? and cycled only until the end of the 200W stage (PCT). During the GXT and PCT, FeO2, FeCO2 and V.E were measured to determine EOM, GE and V.O2max. Integrated electromyography (iEMG) was also used to examine selected muscular activation patterns. Subjects then repeated the tests following the completion of training on their assigned cranks.

Part I: Racemic and asymmetric syntheses of a new substance with prospective antidepressant properties were achieved. In vitro assays with synthetic racemates (±)-25 and (±)-26 suggested that the former is a relatively selective inhibitor of serotonin transporter whereas the latter is a more balanced inhibitor of both serotonin and norepinephrine transporter. An initial approach to enantiomers of 25 and 26 via resolution of carboxylic acids 21 and 22 was unsuccessful but a de novo strategy which introduced asymmetry by means of Charette enantioselective cyclopropanation led to (+)-25, (-)-25, (+)-26 and (-)-26. In vitro assays with (+)-26, now known as synosutine synthesis/OSU), indicate that this substance is a highly effective dual inhibitor of serotonin and norepinephrine transporter. With IC₅₀ and K[subscript i] values in the 1-2 nM range, (+)-26 compares favorably with Eli Lilly's duloxetine (Cymbalta®) as a dual reuptake inhibitor of serotonin and norepinephrine and is thus a potential candidate for development as a drug for treatment of clinical depression. Synosutine was also assayed in vivo for its binding to human monoamine transporters. These studies indicate that synosutine, with a K[subscript i] of 1.2 nM for norepinephrine and 2.1 nM for serotonin, is a more balanced inhibitor than duloxetin. Part II: Synthetic studies towards the tetracyclic core structure of neomangicol A (129) led to advanced intermediate 245 which bears rings A and D of the neomangicol nucleus. This bicylic enone carries the correct stereochemical imprint for tetracycle 129 at C5, C6 and C14 and it contains all of carbon atoms needed to assemble the remaining two rings. Synthesis of bicyclic lactone 170, the precursor for ring A, was accomplished from the monoterpene (S)-(+)-carvone via radical cyclization and a series of Baeyer-Villiger oxidations as the key steps. Alkylation of 170 with alkyl iodide 217, obtained from the monoterpene (S)-(-)-citronellol furnished advanced intermediate 218 which was converted into diene 244. Ring closing metathesis of 244 with Grubbs-Hoveyda second generation catalyst afforded 245. Exploratory functionalization of 245 was carried out for the purpose of assembling rings B and C of the complete neomangicol skeleton. / Graduation date: 2012

Thesis (M.Sc (Pharmaceutics))--North-West University, Potchefstroom Campus, 2009.

The effective of additional muscle mass in a priming exercise on cardiac output (Q) and pulmonary oxygen uptake (VO2) kinetics (mean response time, s) were determined in cyclists. Outcomes were measured over four trials, each consisting of a 6-minute legs alone (UAL) or arms and legs (ULO) warm-up, 3 minute passive recovery, then 6 minutes leg cycling (PAL, PLO; respectively). Q was significantly higher preceding exercise onset with PAL compared to PLO or ULO (0.72 ± 0.13 vs. 0.58 ± 0.09, 0.43 ± 0.09 L∙min-1; respectively, P < 0.05). Q kinetics did not differ between unprimed (ULO: 38.9 ± 8.6) and primed exercise regardless of muscle mass (PLO: 38.6 ± 11.0; PAL: 40.7 ± 11.3). VO2 kinetics were faster (P < 0.05) with PAL (36.9 ± 6.0) compared to ULO (58.7 ± 10.5). Muscle mass employed during priming exercise had only slight effect on subsequent VO2 and Q responses.