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Implication de l’oxygénation cérébrale dans les limitations à l’exercice musculaire des personnes non-entraînées et sportifs d’endurance. L’objectif général de ce travail était de déterminer si l’oxygénation cérébrale était un facteur de la limitation à l’exercice de type aérobie. Dans un premier temps, nous nous sommes attachés à étudier le rôle de l’oxygénation cérébrale mesurée par la Spectroscopie dans le proche Infra-Rouge (NIRS) dans la limitation de l’exercice progressif maximal en rampe. Nous avons montré l’existence d’un seuil de déclin de l’oxygénation cérébrale associé au point de compensation respiratoire (RCP). L’amélioration de la performance avec une supplémentation d’O2 était liée au décalage de ce seuil à de plus hautes intensités d’exercice chez des sujets actifs (étude 1). Dans un second temps, nous avons montré que ce seuil de déclin de l’oxygénation, retrouvé aussi chez des sportifs entraînés en endurance apparaîssait à de plus hautes intensités d’exercice que chez des sujets non-entraînés (étude 2). Enfin, nous avons déterminé l’impact de l’hypoxémie artérielle induite par l’exercice (HIE) des sportifs d’endurance sur l’oxygénation cérébrale au cours d’un exercice maximal en rampe et d’un exercice de temps limite à charge constante. Nous avons ainsi montré que l’oxygénation cérébrale était augmentée avec la HIE suggérant un effet compensatoire à l’hypoxémie artérielle au cours de l’exercice progressif maximal en rampe. Ceci, n’existait pas au cours de l’exercice de temps limite ne supportant pas l’implication de l’oxygénation cérébrale dans ce type d’exercice (étude 3). Ces travaux ont donc mis en évidence l’implication de l’oxygénation cérébrale dans la limitation de l’exercice maximal en rampe chez des sujets actifs et des sportifs entraînés en endurance présentant ou pas une HIE. Toutefois, elle ne semble pas être un facteur majeur de limitation de l’exercice de temps limite. / Involvement of cerebral oxygenation in muscular exercice limitation in untrained and trained endurance men. A decrease in oxygen availability in the brain could be a physiological mechanism limiting aerobic fitness. We first studied the role of cerebral oxygenation measured by Near Infra-Red Spectroscopy (NIRS ) in maximal cycle ramp exercise limitation. We showed a cerebral oxygenation threshold decline associated with respiratory compensation point (RCP). This threshold appeared for higher exercise intensities -related to performance improvement with hyperoxia in untrained endurance men (study 1). Secondly , we showed that the cerebral oxygenation threshold in athletes occurred for higher sub-maximal exercise intensities than untrained (study 2). Finally , we determined the involvement of exercise-induced arterial hypoxemia (EIH) in endurance athletes on cerebral oxygenation during maximal cycle ramp exercice and exercice time to exhaustion. We showed that cerebral oxygenation was improved by EIH suggesting a compensatory effect of EIH during the maximal cycle ramp. This did not occur during exercise time to exhaustion, and does not support the involvment of cerebral oxygenation in this type of exercise (study 3). This work has therefore highlighted the involvement of cerebral oxygenation in maximal cycle ramp exercice limitation in untrained and trained endurance men with or without EIH. However, it was unlikely been the major factor limiting the exercise time to exhaustion.

Thesis (PhD(Agric) (Horticulture))--University of Stellenbosch, 2011. / Includes bibliography. / ENGLISH ABSTRACT: Plums with good taste, aroma and eating quality lead to repeat purchases and sustained demand. Taste includes non-volatile compounds, e.g. sugars and acids, and has been well researched to meet the consumers’ preferences. Plum aroma, however, has not enjoyed the same attention. Limited literature is available on the aroma of Japanese plums and none could be found on the effects of relatively long cold storage on the profiles. The main aim of this study is to investigate the changes in aroma compounds of Japanese plums throughout maturation and ripening and the effects of commercial cold storage regimes. Near infra-red (NIR) spectroscopy was also evaluated as a non-destructive method to determine plum quality parameters aimed at minimising sample variability. In Paper 1, NIR spectroscopy was used to develop prediction models for total soluble solid (TSS), total acidity (TA), sugar-to-acid ratio, firmness and weight in three cultivars (Pioneer, Laetitia and Angeleno) and a multi-cultivar model. Samples were collected for seven consecutive weeks and repeated over two seasons. TSS results showed excellent predictability (R2 = 0.817-0.955; RMSEP= 0.453-0.610 % Brix) but the TA models did not perform well. The sugar-to-acid ratio models had results comparable to that of TSS. Both the firmness and weight models had acceptable results. The models of ‘Pioneer’ and ‘Laetitia’ had a better predictability capacity than the ‘Angeleno’ model. Although the multi-cultivar models outperformed the single cultivar models on R2 values it had higher prediction errors. The robustness of all the TSS, TA and firmness models is high in terms of seasonality, range and cultivar. Papers 2 and 3, the main focus of the study, are concerned with the aroma profile dynamics of Japanese plums. HS-SPME was used in both papers to extract the aroma compounds followed by GC-TOFMS for separation and identification. In Paper 2, the aroma volatile compounds of three cultivars (Pioneer, Laetitia and Angeleno) were determined for a seven week period including samples from three maturity stages (immature, harvest and tree-ripe). A total of 35 compounds were identified of which ten were generic. Each cultivar had five unique compounds resulting in different aroma profiles for each of the maturity stages and distinct separation patterns using discriminant analysis. The study was extended in Paper 3 where the aroma volatile compounds of six cultivars (Pioneer, Sapphire, Laetitia, Songold, Larry Anne and Angeleno) and one plumcot (Flavor King) were determined at three functional stages (commercial harvest, tree-ripe fruit and cold stored fruit). A total of 62 compounds were identified and classified into three groups (‘unique’ (31), ‘generic’ (11) and ‘frequent’ (20)) based on their frequency of occurrence. The aroma profiles of ‘Larry Anne’ and ‘Flavor King’ are the most affected by cold storage conditions and ‘Pioneer’ appears to be the least affected. All the cultivars have significantly different aroma profiles at all three of the functional stages with ‘Sapphire’, ‘Larry Anne’ and ‘Flavor King’ showing the largest differences. ‘Flavor King’, a plumcot, presented a ripe aroma profile that was much diverged from that of the true plums. / AFRIKAANSE OPSOMMING: Pruime met ‘n goeie smaak, aroma en eetkwaliteit lei tot herhaalde verkope en volhoubare aanvraag. Smaak sluit die nie-vlugtige stowwe (suikers en sure) in en is goed nagevors om die verbruikersvoorkeure te bevredig. Pruim aroma het egter nie dieselfde aandag geniet nie. Daar is beperkte literatuur beskikbaar wat handel oor die aroma van Japanese pruime en geen kon gevind word oor die effekte van lang koelopberging op die aromaprofiele nie. Die hoof doel van hierdie studie is om die veranderinge in die aromatiese komponente van Japanese pruime te ondersoek tydens die volwassewording- en rypwordingsprosesse asook die effekte van kommersiele koelopberging. Naby infrarooi (NIR) spektroskopie is ook geevalueer as ‘n nie-destruktiewe manier om pruim kwaliteitsparameters te bepaal met die doel om monstervariasie te beperk. In Artikel 1 is NIR spektroskopie gebruik om voorspellingsmodelle vir totale oplosbare suikers (TOS), totale suur (TS), suiker-tot-suur verhouding, fermheid en gewig te bepaal in drie kultivars (Pioneer, Laetitia en Angeleno) asook ‘n multi-kultivar model. Monsters is vir sewe opeenvolgende weke versamel en herhaal oor twee seisoene. TOS resultate toon uitstekende voorspelbaarheid (R2 = 0.817-0.955; RMSEP= 0.453-0.610 % Brix) maar TS modelle het egter nie so goed gevaar nie. Die suiker-tot-suur verhoudingsmodelle se resultate was vergelykbaar met die van TOS. Beide die fermheid- en gewigsmodelle het aanvaarbare resultate opgelewer. Die modelle vir ‘Pioneer’ en ‘Laetitia’ het ‘n beter voorspelbaarheidskapasiteit getoon as die van ‘Angeleno’. Alhoewel die multi-kultivar model beter presteer het as die enkel kultivar modelle op die R2-waardes was daar meer voorspellingsfoute. Hoe robuustheid is gevind i.t.v. seisoene, datagrense en kultivar vir al die TOS, TA en fermheidsmodelle. Artikels 2 en 3, die fokuspunt van die studie, handel oor die dinamika van die aromaprofiel van Japanese pruime. HS-SPME is in beide artikels gebruik on die aromatiese verbindings te ekstraeer gevolg deur GCTOFMS vir skeiding en identifikasie. In Artikel 2 is die aromatiese stowwe van drie kultivars (Pioneer, Laetitia en Angeleno) bepaal vir sewe opeenvolgende weke en sluit monsters van drie volwassenheidsstadiums in (onvolwasse, oes en boom-rypgemaakte pruime). ‘n Totaal van 35 verbindings is geidentifiseer waarvan tien as generies beskou kan word. Elke kultivar het vyf unieke komponente gehad en het gelei tot verskillende aromaprofiele vir elk van die volwassenheidsstadiums en diverse skeidingspatrone tydens die gebruik van diskriminant analise. Die studie is uitgebrei in Artikel 3 waartydens die aromatiese vlugtige stowwe van ses kultivars (Pioneer, Sapphire, Laetitia, Songold, Larry Anne en Angeleno) en een plumcot (Flavor King) bepaal is tydens drie funksionele stadiums (oes, boom-rypgemaak en koelopgebergde pruime). ‘n Totaal van 62 verbindings is geidentifiseer en in drie groepe geklassifiseer (‘uniek’ (31), ‘generies’(11) en ‘gereeld’ (20)) gebaseer op voorkomsfrekwensie. Die aromaprofiele van ‘Larry Anne’ en ‘Flavor King’ is die meeste deur die koelopberging geaffekteer en ‘Pioneer’ die minste. Al die kultivars het kenmerkend verskil t.o.v. hul aromaprofiele in al drie die funksionele groepe en ‘Sapphire’, ‘Larry Anne’ en ‘Flavor King’ het die grootste verskille getoon. ‘Flavor King’, die plumcot, het ook ‘n ryp aromaprofiel gehad wat baie van die van die egte pruime verskil het.

Submitted by Aelson Maciera (aelsoncm@terra.com.br) on 2017-05-15T19:57:24Z No. of bitstreams: 1 TeseCOF.pdf: 3178869 bytes, checksum: cfad2da3f19b56d42e09c4a472158572 (MD5) / Approved for entry into archive by Ronildo Prado (bco.producao.intelectual@gmail.com) on 2018-02-01T10:55:05Z (GMT) No. of bitstreams: 1 TeseCOF.pdf: 3178869 bytes, checksum: cfad2da3f19b56d42e09c4a472158572 (MD5) / Approved for entry into archive by Ronildo Prado (bco.producao.intelectual@gmail.com) on 2018-02-01T10:55:19Z (GMT) No. of bitstreams: 1 TeseCOF.pdf: 3178869 bytes, checksum: cfad2da3f19b56d42e09c4a472158572 (MD5) / Made available in DSpace on 2018-02-01T11:06:54Z (GMT). No. of bitstreams: 1 TeseCOF.pdf: 3178869 bytes, checksum: cfad2da3f19b56d42e09c4a472158572 (MD5) Previous issue date: 2016-06-24 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Type 2 diabetes mellitus (DM) is responsible for quality of life reduction due its negative impact in the physical exercise capacity. The impairment of cardiopulmonary fitness and lower values in oxygen uptake in exercise tests has been associated with factors related with diabetes complications. Phototherapy is a resource largely utilized due it action in biological systems and it may be adjuvant to exercise to improve muscular efficiency and increase aerobic capacity. Thus, the question if this resource may be benefit to populations with DM. Therefore, we proposed a study protocol randomized, double-blind, placebo controlled to evaluate the acute effect of light emitting diode (LED) in cardiorespiratory and hemodynamic adjustments of moderate exercise in cycloergometer, as well as, in lactate and glucose levels pre and post intervention and after exercise in men aged between 45 and 64 years, with DM and health. Then, two studies were performed. In the study 1 it was evaluated the acute effect of phototherapy (LED-150J) in two groups: DM group (DMG) and health group (HG) (n=16 and n=9, respectively). The groups were paired by age and body mass index. The LED reduced significantly the glucose levels in DMG after exercise and do not affect the lactate levels, cardiorespiratory and hemodynamic adjustments of aerobic exercise in both groups. Our results suggest that LED in combination with moderate exercise decrease acutely the glucose levels in adult subjects with DM. The study 2 aimed evaluate the acute effect of two different doses of phototherapy. Participated in this study two groups of men with DM: LED-150J (n=16) and LED-300J (n=17). The LED-150J reduced the levels of glucose after exercise. The LED-300J increased the lactate levels after exercise in effective session compared with placebo. Any doses changed the cardiorespiratory and hemodynamic adjustments. This study demonstrated that the phototherapy with LED using the 300J dose did not improved the parameters studied and the 150J dose improved the glycaemia and should be used in combination with other therapies for the hyperglycemia management in individuals with DM. The general conclusion of this thesis is that our findings suggest that phototherapy associated with moderate physical exercise have therapeutic potential to control glycaemia in DM, however, further studies should be conducted investigating the dose window and dose-response capable to change acutely the cardiopulmonary and hemodynamic adjustments and lactate levels. / O diabetes mellitus tipo 2 (DM) é responsável por redução significativa na qualidade de vida devido ao seu impacto negativo na capacidade de realização de exercícios físicos. A diminuição do condicionamento cardiopulmonar e os menores valores de consumo de oxigênio pico em testes de exercício têm sido associados com múltiplos fatores envolvidos nas complicações do diabetes. A fototerapia é um recurso que tem sido utilizado devido sua ação nos sistemas biológicos, podendo ser um coadjuvante do exercício na melhora da eficiência do trabalho muscular e aumento da capacidade aeróbia. Por isso, levantou-se a questão de que tal recurso poderia beneficiar populações com DM. Assim, foi proposto um protocolo experimental aleatorizado e duplo-cego visando avaliar o efeito agudo da fototerapia com diodos emissores de luz (LED) nos ajustes cardiorrespiratórios e hemodinâmicos ao exercício moderado em cicloergômetro, bem como nas concentrações de lactato e glicose sanguíneas pré e pós intervenção e após o exercício físico em homens com DM e saudáveis, com idade entre 45 e 64 anos. A partir deste protocolo dois estudos foram realizados. No estudo 1 foi avaliado o efeito agudo da fototerapia (LED-150J) em dois grupos: grupo com DM (GDM, n=16) e grupo saudável (GS, n=9). Os grupos foram pareados por idade e índice de massa corpórea. O LED reduziu significativamente as concentrações de glicose no GDM após o exercício em cicloergômetro e não afetou os níveis de lactato e os ajustes cardiorrespiratórios e hemodinâmicos em ambos os grupos. Nossos resultados sugerem que o LED em combinação com o exercício moderado reduz de forma aguda os níveis de glicose em homens adultos com DM. No estudo 2 objetivou-se avaliar o efeito agudo de duas diferentes doses de fototerapia. Participaram desse estudo dois grupos de homens com DM: LED-150J (n=16) e LED-300J (n=17). O LED-150J reduziu as concentrações de glicose após o exercício físico e o LED-300J aumentou os níveis de lactato após o protocolo de exercício na fototerapia efetiva em comparação com a fototerapia placebo. Nenhuma das dosagens avaliadas modificou significativamente os ajustes cardiopulmonares e hemodinâmicos avaliados. Este estudo mostrou que a fototerapia por meio de LED na dosagem de 300J não causou melhora nos parâmetros estudados enquanto a dosagem de 150J melhorou a glicemia, podendo ser utilizada como recurso adjuvante no controle da hiperglicemia em indivíduos com DM. Como conclusão geral, nossos achados sugerem que a fototerapia associada ao exercício moderado tem potencial terapêutico no controle da glicemia do DM, no entanto, mais estudos são necessários para estabelecer a janela terapêutica e a dose-resposta capaz de modificar de forma aguda os ajustes cardiopulmonares e hemodinâmicos, assim como os níveis de lactato. / FAPESP: 2013/08183-7 / FAPESP: 2015/20512-1 / FAPESP: BEPE 2013/07953-3