Dissertations / Theses on the topic 'Oxygen consumption rate'

Thesis (S. M.)--Massachusetts Institute of Technology, Dept. of Chemical Engineering, 2008.
In title on title page, double-underscored "TM" appears as superscript .
Includes bibliographical references (p. 109-111).
Oxygen consumption rate (OCR) is a reliable indicator of tissue health. Recently, the OCR of isolated human islets has been shown to predict transplant outcome in diabetic mice. The Oxygen Biosensor System (OBS) is a high-throughput, convenient assay that indirectly measures oxygen consumption by measuring oxygen partial pressure, pO2, adjacent to tissue loaded into the OBS multiwell plate. Solving the general species transport equations for a steady-state solution has not accurately converted pO₂ measurements to OCR. Furthermore, the time to reach steady-state is prohibitively long (at least 5 hr). Transient OBS experiments have been conducted and the rate of p02 change has been shown to correlate with the amount of viable tissue, however, no direct relation with OCR has been established. The overall objective of this thesis was to accurately measure OCR using transient OBS measurements. I fabricated flat OBS plates to simplify the geometry for theoretical models, but theoretical simulations did not match well with experimental data. Furthermore, fabricated flat OBS plates did not behave experimentally as would be expected from I-D, slab geometry. Simplified theoretical models were developed to qualitatively understand the effects of silicone rubber thickness, medium volume, and OCR density on the transient behavior of the OBS. It was shown that medium volume and OCR density should be increased as much as well-volume and tissue constraints allow. Commercial OBS plates were used for subsequent experiments, so it was unable to actively control silicone rubber thickness. Transient OBS measurements with both INS-1 cells and islets were correlated with stirred chamber OCR measurements conducted in parallel. The two measurements were linearly related and a calibration curve was developed so that OBS transient measurements could be converted to OCR. The relationship between the two measurements were similar enough for both cells and islets that the calibration curve seems to be independent of tissue geometry.
(cont.) Increased variability of islet tissue caused greater uncertainty about the islet prediction curve. This variability was compared with stirred chamber islet variability and islet sampling is hypothesized to be the underlying cause of high measurement variability with islets.
by Clarke Alan Low.
S.M.

‘Animal personality’ refers to individual behavioural differences that are consistent over time and context. Physiological constraints are suggested to underlie this constraint in behavioural plasticity. As energy is required for physiological processes that generate behaviour, energy metabolism could be a proximate explanation for personality. Currently, the most coherent framework linking behaviour, metabolism and life history-traits is still poorly tested empirically, and studies are showing contradicting results. Therefore, I here aim to explore this relationship further by investigating the relationship between basal metabolic rate (BMR) and personality in Red Junglefowl (Gallus gallus). Birds used had known responses in personality assays, and their metabolic rates were measured by determining oxygen consumption in standardized conditions throughout the night using an open respirometry system. BMR was negatively correlated with time spent foraging, and positively correlated with time spent being vigilant. Considering foraging an ‘activity’ (due to its energy-demand), my results support the allocation model, a model that assumes that an animal has a fixed amount of energy, thus that an energetic trade-off occur between competing energy requiring processes such as BMR and activity. Hence, an animal with low BMR has more energy to spend on activity. However, I do not consider vigilance as an energy-demanding activity; hence this relationship cannot be interpreted in this framework. Taken together, my results show a relationship between personality and BMR, although their relationship still needs further investigation to understand the causality and consequences of it.

To examine if a rhythm can be entrained in either heart rate or oxygen consumption in late stage embryos (days 17-19.5) with light as a zeitgeber, chicken embryos were incubated in complete darkness (D:D) and 12:12 light:dark cycle (L:D). Light had no impact on oxygen consumption (390 µL O2∙min-1∙egg-1) but increased heart rate for non-internally pipped embryos (260 to 270 beats∙min-1 during light cycle). Oxygen consumption increased independent of pipping while heart rate increased (255 to 265 beats∙min-1) in D:D embryos due to pipping. A light-induced rhythm or effect occurred in heart rate but not oxygen consumption, suggesting heart rate and oxygen consumption may be uncoupled.

An increasing amount of hikers have added hiking poles to their outings to aid in reducing fatigue of the lower body and enhance stability. However, very little research has been conducted on the use of poles during continuous uphill hiking. The purpose of this study was to investigate the effect of pole use under field conditions on the rate of perceived exertion, physiological variables [oxygen consumption (VO2), heart rate (HR), non-protein respiratory exchange ratio (RER), & total energy expenditure (TEE)], and time to completion during a 1.68 km continuous uphill (12.6% grade) hike. Ten male and ten female (Mean age = 22.7 ± 2.0 years) hikers participated in this experimental study using a within subject cross over design with randomized, counter-balanced order. Participants hiked with and without poles, at self-selected speeds. Rate of perceived exertion was collected at five minute intervals. Physiological measures (V02, HR, RER, and METs) were measured continuously (every two seconds) during all hiking conditions using a portable metabolic system (VmaxST, SensorMedics, Yorba Linda, CA). Heart rate data was recorded by a Polar transmitter belt worn by the participant with a receiver integrated into the VmaxST base system. Hiking pole use resulted in increased oxygen consumption (M= 29.8 ± 2.6 ml∙kg⁻¹∙min⁻¹ vs. M= 28.6 ± 2.8 ml∙kg⁻¹∙min), and total energy expenditure (M= 223.3 ± 57.9 kcals vs. 209.6 ± 47.7 kcals) compared to hiking without poles. Duration, RER, HR, and RPE were not significantly different between conditions. These results indicate that the use of hiking poles during uphill hiking increases the energy cost of hiking without increasing the perceived exertion in novice pole users. To fully evaluate the effects of hiking pole use and confirm the results from this study, future field research should be conducted with and without poles, including novice and expert groups, at grades above and below 15 %.

This study combines noninvasive hybrid diffuse optical spectroscopies [near-infrared spectroscopy (NIRS) and diffuse correlation spectroscopy (DCS)] with occlusive calibration for continuous measurement of absolute blood flow (BF), tissue blood oxygenation (StO2), and oxygen consumption rate (VO2) in exercising skeletal muscle. Subjects performed rhythmic dynamic handgrip exercise, while an optical probe connected to a hybrid NIRS/DCS flow-oximeter directly monitored oxy-, deoxy-, and total hemoglobin concentrations ([HbO2], [Hb], and [tHb]), StO2, relative BF (rBF), and relative VO2 (rVO2) in the forearm flexor muscles. Absolute baseline BF and VO2 were obtained through venous and arterial occlusions, respectively, and used to calibrate continuous relative parameters. Previously known problems with muscle fiber motion artifact in optical measurements were mitigated with a novel dynamometer-based gating algorithm. Nine healthy young subjects were measured and results validated against previous literature findings. Ten older subjects with fibromyalgia and thirteen age-matched healthy controls were then successfully measured to observe differences in hemodynamic and metabolic response to exercise. This study demonstrates a novel application of NIRS/DCS technology to simultaneously evaluate quantitative hemodynamic and metabolic parameters in exercising skeletal muscle. This method has broad application to research and clinical assessment of disease (e.g. peripheral vascular disease, fibromyalgia), treatment evaluation, and sports medicine.

Twenty-eight endurance trained male volunteers, 18-41 years or age, were studied to determine whether the heart rate-oxygen consumption relationships observed during Bruce protocol stress tests were similar to those observed during steady-state exercise. In addition, maximal oxygen consumption and maximal heart rate values obtained during the stress tests were compared to predicted values. The heart rate-oxygen consumption relationship observed during the stress tests was dissimilar from the relationship observed during the steady-state exercise tests. Heart rate was round to be significantly higher during the stress tests. No significant difference was round in predicted maximal oxygen consumption and maximal heart rate and actual values obtained during the stress tests.
M.S.

Includes abstract.
Includes bibliographical references.
Several methods have been used to quantify the internal training load of a bout of exercise. However, arecent novel approach to quantify the internal training load has been to investigate the dynamic returntowards resting homeostasis at the cessation of exercise. Objective and non-invasive methods ofmonitoring the return towards resting homeostasis include measures of heart rate recovery (HRR) andexcess post-exercise oxygen consumption (EPOC). However, the relative potential of autonomic- vs. metabolic-type recovery measurements to represent the internal training load or homeostatic stress of the preceding exercise bout has not been established. Therefore, the broad aim of this thesis was to investigate the magnitude of EPOC (EPOCMAG), the time constant of the EPOC recovery curve (EPOCτ),HRR within the first minute post-exercise (HRR60s) and the time constant of the HRR curve (HRRτ) as measures which might reflect the homeostatic stress of an exercise bout. It was hypothesized that a measure representing the homeostatic stress of an exercise bout could have the following possible applications; - to identify inter-individual variation in the homeostatic stress of a standardized exercise bout - to detect intra-individual variation in the homeostatic stress of different exercise bouts- to detect intra-individual variation in “readiness to train”, based on the response to a standardized exercise bout. Therefore, the investigations of this thesis aimed to assess the relative potential of EPOCMAG, EPOCτ,HRR60s and HRRτ in these different roles. The experimental work was divided into 4 studies.

Sphingosine 1-phosphate (S1P) is a cellular signaling molecule that has been implicated in a variety of diseases including cancer, fibrosis, Alzheimer's, and sickle cell disease. It is formed from the phosphorylation of sphingosine (Sph) by sphingosine kinase (SphK) and SphK exists as two isoforms-"SphK1 and SphK2, which differ with respect to their cellular activity and localization. As the key mediators in the synthesis of S1P, SphKs have attracted attention as viable targets for pharmaceutical inhibition. To validate their potential as therapeutic targets, we aimed to develop potent, selective, and in vivo active inhibitors of SphK. Herein, we describe the design, synthesis and biological evaluation of SphK2 inhibitors. We first describe the development of six SphK2 inhibitors that assess the utility of replacing lipophilic tail groups with heterocyclic rings. These six compounds demonstrate that the lipid binding pocket for SphK2 cannot accommodate compounds with tail groups that are conformationally restricted or positively charged. We then describe the development of aminothiazole-based analogues of an SphK1-selective inhibitor. A library of 37 aryl-substituted aminothiazole tail groups were synthesized, revealing a structure-activity relationship study that examines electronic effects on the aryl-substituted aminothiazoles and the effect of modifying the amino portion of the aminothiazole. These molecules show surprisingly good potency and selectivity for SphK2. In particular, we highlight 3.20dd (SLC4101431), a biphenyl aminothiazole that is the post potent and selective SphK2 inhibitor to date, with an SphK2 Ki of 90 nM and 100-fold selectivity for SphK2. This molecule's in vivo activity will also be discussed. Mitochondrial uncouplers are small molecules that shuttle protons from the inter membrane space to the mitochondrial matrix independent of ATP synthase, which disrupts oxidative phosphorylation and promotes increased nutrient metabolism for homeostasis to be maintained. Consequently, small molecule mitochondrial uncouplers have been pursued as probes for mitochondrial function and as potential therapeutics for the treatment of obesity and type 2 diabetes. Herein, we describe the design, synthesis, and biological evaluation of small molecule mitochondrial uncouplers. We report a library of 52 compounds that have good mitochondrial uncoupling activity over a wide therapeutic range, including 5.16t (SHC4111522) and 5.17i (SHC4091665), which have EC50 values of 0.63 uM and 1.53 uM, respectively, and achieve at least 2-fold increase in oxygen consumption rates relative to basal levels. With these molecules, we demonstrate that pKa and cLogP significantly contribute to uncoupling activity and must be accounted for when developing new generation small molecule mitochondrial uncouplers.
Ph. D.

Superior swimming stamina in adult fish is presumably passed on to their offspring, but the ontogeny of the appearance of superior stamina and the requisite enhanced cardio-respiratory support for locomotion in larval fishes has not been determined. Is the expression of the suite of parental traits enabling superior swimming stamina in their offspring dependent upon their achieving juvenile/adult morphology, or does it appear earlier in their larvae? To answer this, adults were classified into three groups based on swimming stamina, followed by measurement of length, mass, and width. Larval offspring from the two parental groups -high stamina larvae (HSL) and low stamina larvae (LSL)- were reared at 27°C in aerated water (21% O2). Routine and active heart rate, routine and active mass specific oxygen consumption were recorded through 21dpf, and cost of transport (COT) and factorial aerobic scope were derived from oxygen consumption measurements. Routine heart rate at 2dpf of LSL was 164 ± 1 b·min-1, compared to only 125 ± 2 b·min-1 for HSL. Routine heart rate subsequently peaked at 203 ± 1 b·min-1 at 5dpf in the HSL group, compared to 207 ± 1 b·min-1, at 4dpf in the LSP larvae. Active heart rate at 5 dpf of LSL was 218 ± 2 b·min-1 compared to 216 ± 2 b·min-1 for HSL. Active heart rate increased slightly to 227 ± 2 b·min-1 for LSL before decreasing again, while active heart rate remained relatively constant for HSL. Routine O2 consumption at 2dpf of HSL was 0.09 μmol·mg-1·hr-1, compared to 0.03 μmol·mg-1·hr-1 in LSL. Routine O2 consumption subsequently peaked at 0.70 μmol·mg-1·hr-1 at 9dpf in the HSL, compared to 0.71 μmol·mg-1·hr-1, at 9dpf in the LSL. These values dramatically decreased before leveling off at around 0.20 μmol·mg-1·hr-1 and 0.15 μmol·mg-1·h-1, respectively. Active O2 consumption at 5dpf for HSL was 0.38 μmol·mg-1·hr-1, compared to 0.57 μmol·mg-1·hr-1 for LSL. Active O2 consumption subsequently peaked at 0.97 μmol·mg-1·hr-1 at 10dpf in HSL, compared to 1.19 μmol·mg-1·hr-1 at 7dpf in LSL. These values also dramatically decreased and leveled off. Significant differences (p < 0.05) in heart rate and oxygen consumption persisted through 21dpf. The onset of differences observed in routine and active heart rate in early larvae, correlated with parent stamina, show that juvenile or adult features are not required as a precondition for the emergence of phenotypic physiological differences.

Established interspecific metabolic allometric relationships do not adequately describe the complexity and variable physiological states of developing animals. Consequently, intraspecific allometric relationships of oxygen consumption and carbon dioxide production as a function of body mass; the respiratory quotient; the function of the silk cocoon; and body composition were investigated for each distinct developmental stage of the silkworm, Bombyx mori. Whole animal O2 consumption in Bombyx ranged from 0.00064 + 0.000047 ml O2 .hr-1 at larval instar I to 0.77 + 0.06 ml O2 .hr-1 in pre-pupal, falling to 0.21+ 0.01 ml O2 .hr-1 in the pupae. Those instars having a significant relationship between O2 consumption as a function of body mass, the slope of the line relating O2 consumption to body mass varied between 0.99 and 1.02, while across all instars the slope was 0.82. Developmental allometry should be presented for individual developmental stages because the individual allometric exponents of the stages can be significantly different from the overall allometric exponent throughout development and in some cases, the overall allometric exponent can be a statistical artifact. The first larval instar of Bombyx mori has the lowest cross sectional area of high metabolic tissue of the midgut (27%) and had one of the highest percentages of some metabolically inert tissues (i.e. lipid, 7.5%). Body composition of the first instar does not support the idea that smaller mass animals having the highest O2 consumption are composed of a greater percentage of metabolically active organs when compared to larger animals. However, this developmental stage has the highest percentage of the mitochondrial marker cytochrome oxidase, which correlates well with the high O2 consumption rate of the smaller mass. Therefore, established interspecific principles should not be assumed to function as valid models for intraspecific developmental relationships of metabolism as a function of body mass. Developmental allometry should include an analysis of individual stages of development as well as an analysis of development as a whole to gain a comprehensive understanding of the complexity of allometry of the developing animal such as the silkworm.

Despite its essential role in bioenergetic modeling, reliable measures of energy expenditure (i.e., oxygen consumption) associated with the different activities of wild animals have remained elusive. Oxygen consumption rate (VO₂) associated with activity can be estimated as a function of heart rate (fh), and the empirical relationship between the two has been determined for several aquatic vertebrates while fasting and resting. However, the simplified fh:VO₂ relationships established from such studies may differ under more complex physiological circumstances, such as when animals are foraging at depth or feeding on prey. I assessed the efficacy of using fh to predict VO₂ in 7 captive Steller sea lions, Eumetopias jubatus, while fasting and feeding at rest (on land or in water) and while diving (up to 40 m in the open ocean). Linear mixed-effects models revealed that environment, amount of food fed, and type of diving activity all altered the fh:VO₂ relationship. They also showed that different linear equations are needed to predict VO₂ from fh for sea lions fasted while on land or in water, but that a single equation can predict VO₂ on land regardless of whether fasted or feeding. When in water, feeding animals a 4, 6, or 12 kg meal changed the fh:VO₂ relationship compared to fasted animals. While fh can reliably be used to predict VO₂ in diving sea lions, the relationship differed between single dive cycles (one dive +surface interval) and dive bout cycles (multiple dives+surface intervals). However, the equation that predicted VO₂ for single dive cycles did not differ from that for sea lions resting on the surface. Neither dive duration, dive depth, nor food consumed significantly affected the fh:VO₂ relationships. Heart rate could be used to predict VO₂ in diving sea lions, but only over complete dive cycles or dive bouts where animals recovered fully from the O₂ debt incurred underwater. Based on these results, separate equations that distinguish among environmental, digestive, and diving states can be employed to accurately predict VO₂ from heart rate in wild Steller sea lions.

Harmful algal blooms (HABs) are natural occurrences that can severely impact marine communities. Depending on the species, they can produce a wide array of toxins, which may elicit devastating effects on marine life. Diarrhetic Shellfish Poisoning (DSP) is a specific type of food poisoning, characterized by severe gastrointestinal illness due to the ingestion of filter feeding bivalves contaminated with a specific suite of toxins such as okadaic acid (OA) and dinophysistoxins (DTXs). OA and DTXs are lipophilic and heat-stable compounds that frequently accumulate in bivalve mollusks along European coasts. It is established that organisms such as bivalves accumulate these toxins in their tissues, mostly in the digestive gland, through their filter feeding behavior acting therefore as a vectors for other organisms such as planktivorous fish. Here, for the first time, the time course of accumulation and elimination of Diarrhetic shellfish toxins (DSTs) in juveniles of Zebra seabream (Diplodus cervinus) was assessed during an experimental period of 15 days. It was shown that fish present a high excretion rate and low toxin conversion, in fact no other compounds except for DTX-1 were found. Then fish aerobic metabolism and swimming performance were investigated, exposing individuals to OA group of toxins via dietary route during 3 days, after which fish were challenged with increasing swimming velocity trials using a swim tunnel respirometer. Results show that OA impaired on metabolic performance, assessed both during the standard metabolic rate (SMR) and during the maximum metabolic rate (MMR) as an oxygen consumption increment. Moreover, from critical swimming speed (Ucrit) analysis, significant differences among the two tested groups were observed. In conclusion, these studies show that fish can act temporary as a vector and, although a high elimination rate was found, at the same time toxins ingestion was able to impair their fitness.

Syfte med denna studie var att undersöka energiförbrukningen vid havspaddling. Energiförbrukningen undersöktes i vila och vid två olika hastigheter (4 och 7 km/h), först med en olastad och sedan med en lastad kajak (20 kg). Dessutom undersöktes hur det passiva motståndet förändrades vid successivt ökad hastigheten. Studien genomfördes i en försöksgrupp med jämn könsfördelning och med varierande ålder och paddlingserfarenhet. I studiens första del uppmättes försökspersonernas hjärtfrekvens i förhållande till syrgasupptag och koldioxidproduktion vid en successivt ökad belastning i en kajakergometer. För varje försöksperson kunde sedan en korrelationskurva beräknas mellan hjärtfrekvens och syrgasupptag. Utifrån den hjärtfrekvens som sedan försökspersonen hade under paddlingen kunde syrgasupptaget beräknas. Vid paddling med en olastad kajak och en hastighet av 4 km/h beräknades syrgasupptaget till 5 ml/kg/min. Vid en hastighet 7 km/h så ökade syrgasupptaget signifikant till 11.5 ml/kg/min (p< 0.05). Vid paddling med en lastad kajak så ökade syrgasupptaget signifikant från 6,5 ml/kg/min vid 4 km/h till 14,5 ml/kg/min (p< 0.05) vid 7 km/h. Om energiförbrukningen beräknas utifrån syrgasupptaget för en person på 75 kg skulle en paddelhastighet på 4 km/h innebära en förbrukning på 458 kJ (107,4 kcal/h) med en olastad kajak och 585 kJ (139.8 kcal/h) med en lastad kajak. Vid 7 km/h var motsvarande värden 1080 kJ (258 kcal/h) (olastad kajak) och 1350 kJ (322 kcal/h) (lastad kajak). Det passiva motståndet ökade exponentiellt med ökad hastighet.
The aim of this study was to examine energy consumption when sea kayaking. The energy consumption was examined at rest and at two different speeds (4 and 7 km/h respectively), first with an empty and then with a packed kayak (20 kg). Moreover, the kayaks’ passive drag in the water was measured in order to examine how this was influenced by the speed through the water. The study was implemented in a group of paddlers with even gender distribution but with varying age and experience. In the first part of the experiment, we measured the participants’ heart frequency, oxygen uptake and carbon dioxide production during gradually increased work load in a kayakergometer. For each test subject correlation curves were constructed from the recorded heart rate and oxygen uptake. Based on the persons heart rate during paddling, oxygen uptake was calculated using the individual regression equation which was calculated in the first part of the experiment. When paddling at 4 km/h with an unpacked kayak, the oxygen uptake was measured to 5 ml/kg/min. At 7 km/h, it increased significantly to 11.5 ml/kg/min (p< 0.05). Paddling with a packed kayak oxygen consumption increased to 6.5 ml/kg/min at 4 km/h and significantly to14.5 ml/kg/min at 7 km/h. If energy consumption is calculated on the basis of oxygen uptake for a person weighing 75 kg, at 4 km/h this corresponds to a consumption of 450 kJ (107.4 kcal/h) when kayaking with an unpacked kayak and 585 kJ (139.8 kcal/h) with a packed ditto. At 7 km/h, energy consumption was calculated to 1080 kJ (258 kcal/h) (empty kayak) and 1350 kJ (322 kcal/h) (packed kayak). The passive drag increased exponentially with increased speed.

The purpose of the present investigation was to: 1) Determine the relationship between cardiac output (estimated using the acetylene rebreathing methodology) and oxygen consumption in a homogeneous group of men who are paraplegic. 2) Investigate whether lower limb elevation increases stroke volume and decreases heart rate at rest and during submaximal arm exercise. 3) Investigate whether the application of constant circumferential pneumatic pressure applied to dependent lower limbs increases stroke volume and decreases heart rate at rest and during submaximal arm exercise.

Tyrimo objektas. Vidutinių ir ilgų nuotolių bėgikų aerobinis pajėgumas ir kvėpavimo sistemos rodiklių sąryšis. Tyrime dalyvavo 19 vidutinio bei didelio meistriškumo vidutinių (pagrindinis varžybinis nuotolis – nuo 600 m iki 2 km, n =9) ir ilgųjų (3 km arba daugiau, n =10) nuotolių bėgikai. Tiriamiesiems buvo atliktas kvėpavimo sistemos funkcinės būklės nustatymas ramybėje ir aerobinio pajėgumo nustatymas atliekant nepertraukiamą nuosekliai didėjantį krūvį. Tikslas - nustatyti vidutinių ir ilgų nuotolių bėgikų aerobinio pajėgumo ir kvėpavimo sistemos funkcijos ypatumus. Darbo uždaviniai: 1. Palyginti vidutinių ir ligų nuotolių bėgikų aerobinį pajėgumą. 2. Palyginti vidutinių ir ligų nuotolių bėgikų kvėpavimo sistemos funkcinius rodiklius. 3. Įvertinti sąryšį tarp bėgikų aerobinio pajėgumo ir kvėpavimo sistemos funkcijos rodiklių. Išsikėlėme hipotezę, kad kvėpavimo funkcinės galimybės dėl skirtingo intensyvumo treniruotės ir varžybinių krūvių turėtų būti didesnės tarp vidutinių nuotolių bėgikų, o aerobinės ištvermės rodikliai turėtų būti didesni tarp ilgų nuotolių bėgikų. Išvados 1. Absoliutus maksimalus deguonies suvartojimas lyginant vidutinių ir ilgų nuotolių bėgikus nesiskiria, o santykinės šio rodiklio reikšmės reikšmingai didesnės ilgų nuotolių bėgikų grupėje. 2. Ilgų nuotolių bėgikų pirmasis ventiliacinis slenkstis ir jį atitinkantis ŠSD didesni ilgų nuotolių bėgikų grupėje, nors maksimalios ŠSD reikšmės nuosekliai didinamo krūvio metu nesiskiria. 3. Bėgimo... [toliau žr. visą tekstą]
Object of research. Middle distance and long distance runners aerobic capacity and the connection of respiratory system indicators. We researched 19 superior level middle distance (main competition distance from 600m to 2 km, n = 9) and long distance (3 km or more, n = 10) runners. Researched sportsman have undergone respiratory system functional condition test in tranquility state and aerobic capacity test during consecutively heavier physical load. Goal of research. To determine the functional features of middle distance and long distance runners aerobic capacity and respiratory system. Tasks: 1. To compare aerobic capacity between middle distance and long distance runners. 2. To compare respiratory system functional indicators between middle distance and long distance runners. 3. Analyze and connection between runners aerobic capacity and respiratory system indicators. Hypothesis. Because of different training intensiveness and competition loads, functional capacities of respiration system are greater of the middle distance runners, and aerobic capacity indicators are greater of the long distance runners. Conclusion. 1. Absolute maximum oxygen consumption is almost the same of both middle distance and long distance runners, while relative indicators are significantly greater in the long distance runners group 2. Long distance runners first ventilator threshold and its corresponding heart contraction rate is greater in the long distance runners group, while maximum heart... [to full text]

O objetivo deste estudo foi investigar as contribuições dos sistemas energéticos e do gasto energético total em situação de luta. A amostra foi composta de 10 atletas do sexo masculino de nível nacional/internacional (21±6 anos; 176.2±5.3cm; 67.2±9.0kg), competindo em nível internacional. Para a estimativa das contribuições energéticas e do gasto energético total, foram realizados três protocolos simulando combate (um round, dois rounds e três rounds). As lutas foram filmadas para quantificação das ações motoras em cada round. A estimativa dos sistemas energéticos aeróbio (WAER), anaeróbio alático (WPCR) e anaeróbio lático (W[La-]) foi realizada através do consumo de oxigênio durante a atividade, do delta da concentração sanguínea de lactato de cada round e do débito alático de oxigênio (DAO2), respectivamente. A razão entre as ações de elevada intensidade e momentos de baixa intensidade (step e pausa) no protocolo 3 foi ~1:7. Os resultados dos sistemas WAER, WPCR e W[La-] no protocolo 3 foi 120±22kJ (66±6%), 54±21kJ (30±6%), 8,5kJ (4±2%), respectivamente. Assim, as sessões de treinamento devem ser direcionadas principalmente para a melhoria do sistema anaeróbio alático (responsável pelas ações de alta intensidade), e do sistema aeróbio (responsável pelo processo de recuperação entre as ações de alta intensidade)
The purpose of this study was to investigate energy system contributions and energy cost in combat situation. The sample was constituted by 10 male taekwondo athletes at national/international level (age: 21±6 years old; height: 176.2±5.3cm; body mass: 67.2±9.0kg) competing at national/international level. To estimate the energy contributions and total energy cost of the fights, athletes performed a three different protocols simulated competition (1 round, 2 rounds and 3 rounds). The combats were filmed in order to quantify the actual time spent fighting in each round. The estimate of the aerobic (WAER), anaerobic alactic (WPCR) and anaerobic lactic (W[La-]) energy systems was carried out through the oxygen consumption during the activity, the fast component of excess post-exercise oxygen consumption, and the delta of blood lactate concentration in each round, respectively. The mean data between the high intensity actions and moments of low intensity (step and pause) was ~1:7. The results of WAER, WPCR and W[La-] system contributions were 120±22kJ (66±6%), 54±21kJ (30±6%), 8,5kJ (4±2%), respectively. Thus, training sessions should be directed mainly to the improvement of the anaerobic alactic system (responsible by the high-intensity actions), and of the aerobic system (responsible by the recovery process between high-intensity)

The purpose of the present investigation was to: 1) Determine the relationship between cardiac output (estimated using the acetylene rebreathing methodology) and oxygen consumption in a homogeneous group of men who are paraplegic. 2) Investigate whether lower limb elevation increases stroke volume and decreases heart rate at rest and during submaximal arm exercise. 3) Investigate whether the application of constant circumferential pneumatic pressure applied to dependent lower limbs increases stroke volume and decreases heart rate at rest and during submaximal arm exercise.
Thesis (Masters)
Master of Philosophy (MPhil)
School of Physiotherapy and Exercise Science
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This research investigates various applications of diffuse correlation spectroscopy (DCS) on in-vivo human muscle tissue, both at rest and during dynamic exercise. Previously suspected muscle tissue relative blood flow (rBF) baseline shift during extended measurement with DCS and DCS-Near infrared spectroscopy (NIRS) hybrid optical systems are verified, quantified, and resolved by redesign of optical probe and alteration in optical probe attachment methodology during 40 minute supine bed rest baseline measurements. We then translate previously developed occlusion techniques, whereby rBF and relative oxygen consumption rV̇O2 are calibrated to initial resting absolute values by use of a venous occlusion (VO) and arterial occlusion (AO) protocol, respectively, to the lower leg (gastrocnemius) and these blood flows are cross validated at rest by strain gauge venous plethysmography (SGVP). Methods used to continuously observe 0.5Hz, 30% maximum voluntary isometric contraction (MVIC) plantar flexion exercise via dynamometer are adapted for our hybrid DCS-Imagent diffuse optical flow-oximeter in the medial gastrocnemius. We obtain healthy control muscle tissue hemodynamic profiles for key parameters BF, V̇O2, oxygen saturation (StO2), deoxyhemoglobin, oxyhemoglobin, and total hemoglobin concentrations ([Hb], [HbO2], and THC respectively), as well as systemic mean arterial pressure (MAP) and pulse rate (PR), at rest, during VO/AO, during dynamic exercise and during 15 minute recovery periods. Next, we began investigation of muscle tissue hemodynamic disease states by performing a feasibility pilot study using limited numbers of controls and peripheral arterial disease (PAD) patients using the translated methods/techniques to determine the ability of our technology to assess differences in these populations.

Considérée comme une préoccupation de tous, la santé n’est pas un concept facile à cerner. S’il n’existe pas une définition universelle de la santé, ses différents usages et acceptions permettent toutefois d’en préciser les dimensions biologique, psychique et sociale. En santé animale, la dimension biologique demeure la plus étudiée, mais il n’existe pas pour autant de définition consensuelle à portée internationale de la santé animale. Dès lors comment appréhender la santé chez les mollusques marins ? Un être vivant peut être décrit fonctionnellement en physiopathologie par le suivi de biomarqueurs en conditions de laboratoire. Chez l’être humain et de nombreux animaux, des valeurs « normales » de biomarqueurs ont été proposées ; celles-ci ont été déterminées en réalisant des mesures ou des observations chez des échantillons de populations réputées en « bonne santé », la sélection rigoureuse de ces populations et échantillons constituant un enjeu majeur. Cette démarche a longtemps reposé sur l’idée qu’un être vivant est en « bonne santé » quand il est dans la « norme », ou exprimé autrement, que ses valeurs de biomarqueur s’inscrivent dans la distribution de valeurs du biomarqueur obtenues chez une population en « bonne santé ». Différentes étapes ont ensuite conduit à faire évoluer la terminologie des valeurs « normales » ou usuelles, parfois nommées constantes médicales, pour préférer celles de valeurs de référence et d’intervalles de référence. Les définitions de ces termes ainsi que leur détermination ont fait l’objet de nombreuses publications et de normes internationales qui constituent le corpus scientifique de la théorie des valeurs de référence. Après avoir choisi des biomarqueurs d’intérêt sur la santé biologique chez l’huître creuse Crassostrea gigas (premier enjeu), constituer des populations d’huîtres creuses supposées saines (deuxième enjeu), est-il possible dans une première étude de déterminer des intervalles de référence de ces biomarqueurs dans un groupe échantillon de référence (troisième enjeu), puis de vérifier qu’ils apportent des éléments d’information permettant d’émettre des hypothèses sur la santé, en réalisant des études complémentaires de comparaison avec les valeurs observées de biomarqueurs chez des huîtres creuses infectées expérimentalement par des organismes pathogènes, le virus OsHV-1 (ostreid herpesvirus type 1) d’une part, la bactérie Vibrio aestuarianus d’autre part (quatrième enjeu) ?
Of interest of everyone, health is not an easy concept to figure out. Although there is no universal definition of health, its various uses and meanings allow us to specify its biological, psychic and social dimensions. In animal health, the biological dimension remains the most studied, there is therefore no consensual definition of international animal health. So how to understand the health of marine shellfish? A living being can be functionally described in physiopathology by monitoring biomarkers under laboratory conditions. In men and many animals, "normal" biomarker values have been proposed; these have been determined by carrying out measurements or observations in samples of healthy populations, the rigorous selection of these populations and samples being a major issue. This approach has long been based on the idea that a living being is in "good health" when it is in the "norm", or otherwise expressed, that its biomarker values are part of the distribution of biomarker values obtained in a population in "good health". Different stages then led to changing the terminology of "normal" or usual values, sometimes called medical constants, to prefer those of reference values and reference intervals. The definitions of these terms and their determination have been the subject of numerous publications and international standards which constitute the scientific body of the theory of reference values. After choosing biomarkers of interest in biological health in the Pacific oyster Crassostrea gigas (first issue), to establish healthy oyster populations (second issue), is it possible in a first study to determine reference intervals of these biomarkers in a reference sample group (third issue), then to verify that they provide elements of hypotheses on the health, by carrying out complementary studies of comparison with the observed values of biomarkers in Pacific oysters experimentally infected by pathogens, OsHV-1 (ostreid herpesvirus type 1) on the one hand, Vibrio aestuarianus on the other (fourth issue)?

SUMMARY THE RELATIONSHIP BETWEEN PUPILS' BODY COMPOSITION, PHYSICAL ACTIVITY AND RECOVERY SPEED AFTER PHYSICAL EXERCISE Hypothesis. We thought that pupils’ who have higher physical activity and normal body weight also have faster recovery after physical exercise. Objectives of the study. To identify the relationship between pupil’s body composition, physical activity and recovery rate after physical load. The aim of the study: 1. To identify the relationship between physical activity and body composition. 2. To identify the relationship between body composition and recovery rate after physical activity. 3. To identify the relationship between physical activity and recovery speed after physical exercise. Subjects. It was made of a group of 40 healthy (20 girls and 20 boys), 10-12 form pupils, chosen by chance, from one Kaunas secondary school. Methods: According to the questionnaire, applying the indirect test technique of maximum oxygen consumption (VO2max), suggested by Huston university. Was estimated pupils physical activity and VO2max. According to the data of the questionnaire, the analysed have been divided into 3 groups of physical activity (PA): low PA; medium PA; high PA. The body composition of the investigated has been measured according bioelectrical impedance method. The following indicators have been measured: body weight, body weight index (BWI); relative fat mass (%); fat free mass (kg), total water amount (kg). To establish functional capacity of... [to full text]

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CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Introdução: A marcha de amputados de membros inferiores (MMII) envolve maior consumo de oxigênio (VO2), justificado por meio das alterações biomecânicas. Apesar dos estudos não associarem as variáveis cardiovasculares e a capacidade física com o maior VO2 durante a marcha de amputados de MMII, esses indivíduos possuem alterações autonômicas e cardiovasculares em repouso e diminuição da capacidade aeróbia. Objetivo: Testar a hipótese que os amputados transtibiais traumáticos apresentam maior VO2 em repouso, que, associado às alterações cardiovasculares, interferem no VO2 durante a marcha e exercício aeróbio envolvendo os membros superiores. Métodos: Foram avaliados 22 indivíduos adultos, do sexo masculino, 11 com amputações transtibiais unilaterais traumáticas, comparados a 11 indivíduos sem amputações. Os voluntários foram avaliados em relação à frequência cardíaca (FC), pressão arterial (PA) e VO2, este por meio do analisador de gases K4 b² Cosmed. Todos os indivíduos foram avaliados em repouso, na postura supina e ortostática, em um protocolo de marcha na esteira rolante e em um protocolo contínuo no cicloergômetro de membros superiores (MMSS). Para comparação entre os grupos, foi utilizado o teste t de Student e o de Mann Whitney, este para o VO2 e, para correlacionar as variáveis, a Correlação de Spearman (p<0,05). Resultados: Na postura supina e ortostática, os amputados apresentaram maiores valores de PA, FC e VO2. O VO2 obtido na postura ortostática dos amputados foi correlacionado de forma positiva com a FC obtida nessa postura e com o VO2 em supino. Durante a marcha, os amputados apresentaram maior FC, PA, VO2 e este correlacionou-se positivamente com o VO2 na postura supina e com a FC durante a marcha. Durante o protocolo contínuo de MMSS, os amputados apresentaram maior VO2 e PAS. Conclusão: Os amputados transtibiais traumáticos apresentaram alterações cardiovasculares e metabólicas em repouso, que interferiram no VO2 durante a marcha e postura ortostática. Confirmando a presença de alterações não mecânicas, relacionadas ao VO2, os amputados transtibiais também apresentaram maior VO2 e FC durante a atividade aeróbia que não envolveu os MMII.
Introduction: The gait of lower limb amputees involves a higher oxygen consumption (VO2), justified by the biomechanical alterations. Although the studies do not associate the cardiovascular variables and the physical capacities with the higher VO2 during the gait of lower limb amputees, these subjects have autonomic and cardiovascular alterations in rest and decrease in the aerobic capacity. Aim: Test the hypothesis that the transtibial traumatic amputees show higher VO2 at rest, which associated with cardiovascular alterations, interfere on the VO2 during the gate and aerobic exercise involving the upper limbs. Methods: Were assessed 22 adult subjects, male, 11 with one-sided transtibial traumatic amputations, compared to 11 subjects with no amputations. The volunteers were assessed through the heart rate (HR), blood pressure (BP) and VO2, by the gases analyzer K4 b² Cosmed. All the subjects were assessed in rest, in the supine and orthostatic position, in a gait protocol on the treadmill and in a continuous protocol on the upper limbs cycle ergometer. For comparison between the groups, were used the t-Student and the Mann Whitney tests, for the VO2, and to correlate the variables, the Spearman Correlation. Results: On the supine and orthostatic position, the amputees showed higher values of BP, HR and VO2. The VO2 obtained on the amputees’ orthostatic position was correlated positively with the HR obtained in this position and with the VO2 in supine. During the gait, the amputees showed higher HR, BP and VO2, this correlated positively with the VO2 on the supine position and with the HR during the gait. During the continuous protocol of upper limbs, the amputees showed higher VO2 and BP Conclusion: The transtibial traumatic amputees showed cardiovascular and metabolic alterations at rest, which interfered in the VO2 during the gait and orthostatic position. Confirming the presence of non mechanic alterations, related to the VO2, the transtibial amputees also showed higher VO2 and HR during the aerobic activity that did not involve the lower limbs.

Context: The metabolic syndrome, characterized by central obesity with dyslipidemia, hypertension, and hyperglycemia, identifies people at high risk for type 2 diabetes. Objective: Our objective was to determine how the insulin resistance of the metabolic syndrome is related to muscle fiber composition. Design:Thirty-nine sedentary men and women (including 22 with the metabolic syndrome) had insulin responsiveness quantified using euglycemic clamps and underwent biopsies of the vastus lateralis muscle. Expression of insulin receptors, insulin receptor substrate-1, glucose transporter 4, and ATP synthase were quantified with immunoblots and immunohistochemistry. Participants and Setting: Participants were nondiabetic,metabolic syndrome volunteers and sedentary control subjects studied at an outpatient clinic. Main Outcome Measures: Insulin responsiveness during an insulin clamp and the fiber composition of a muscle biopsy specimen were evaluated. Results: There were fewer type I fibers and more mixed (type IIa) fibers in metabolic syndrome subjects.Insulin responsiveness and maximal oxygen uptake correlated with the proportion of type I fibers.Insulin receptor,insulin receptor substrate-1, and glucose transporter 4 expression were not different in whole muscle but all were significantly less in the type I fibers of metabolic syndrome subjects when adjusted for fiber proportion and fiber size.Fat oxidation and muscle mitochondrial expression were not different in the metabolic syndrome subjects. Conclusion:Lower proportion of type I fibers in metabolic syndrome muscle correlated with the severity of insulin resistance. Even though whole muscle content was normal, key elements of insulin action were consistently less in type I muscle fibers, suggesting their distribution was important in mediating insulin effects

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A bicicleta aquática Hidrocycle® possui sistema para gerar resistência, denominado Evolution®, que consiste em quatro calhas retangulares dispostas perpendicularmente movimentadas pelo giro dos pedais. Neste sistema há duas maneiras para controlar a carga: 1) velocidade de pedalada (RPM) e 2) alteração da área frontal das calhas (AF) em três níveis, AF1, AF2 e AF3. Para utilização mais precisa no treinamento, torna-se necessário o estudo das variáveis que atuam no controle da intensidade do exercício do sistema Evolution®, freqüência cardíaca (FC), percepção do esforço (PE), tensão muscular, consumo de oxigênio (VO2), gasto calórico e concentração de lactato [La] em resposta às variações de RPM e AF. Portanto, os objetivos do estudo foram verificar: 1) A resposta da FC e PE em teste progressivo de esforço realizado em duas profundidades, cicatriz umbilical e processo xifóide; 2) Identificar VO2max, [La]max, FCmax e PE para cada AF do sistema Evolution® em protocolo progressivo de cargas e predizer o gasto calórico e potência gerada protocolo de carga submáxima constante. Para o estudo 1, a amostra foi constituída por 10 homens e mulheres ativos, submetidos a dois testes progressivos, um em cada profundidade. Para o estudo 2, 15 homens, fisicamente ativos realizaram 3 testes máximos, um com cada AF e um teste de carga constante submáxima para predição do gasto calórico e potência gerada. No estudo 1, os valores máximos de FC e PE apresentaram diferenças estatisticamente significantes ao serem comparados nas duas profundidades. Já a FC por estágio de RPM, apresentou a partir do terceiro estágio tendência a ser mais alta, sendo evidente a diferença a partir do sétimo estágio na altura do processo xifóide. O estudo 2 verificou-se que não há diferença nos valores máximos de FC, VO2, [La] e PE nas 3 AF estudadas em teste máximo, porém os valores ocorrem em RPM diferentes, revelando que quanto maior a AF, menor é a RPM para se atingir os máximos para FC, VO2, [La1] e PE. Para o mesmo estudo, permitiu predizer o VO2 a partir das variáveis AF, RPM. Conclui-se que o sistema Evolution® da bicicleta aquática Hidrocycle® permite adequar a sobrecarga de exercício, assim como sua predição facilitando a aplicação do equipamento nas diversas áreas do treinamento físico.
The aquatic bicycle Hidrocycle® has a system to generate resistance, called Evolution®, which consists of four rectangular troughs arranged perpendicularly moved by the rotation of the pedals. In this system there are two ways to control the load: 1) the pedaling speed (rpm) and 2) change in the frontal area of ducting (AF) in three levels, AF1, AF2 and AF3. To use more precise training, it is necessary to study the variables that act in the control of exercise intensity Evolution® system, heart rate (HR), perceived exertion (PE), muscle tension, oxygen consumption (VO2) and lactate concentration [La] in response to changes in RPM and AF. Therefore, the objectives of the study were: 1) The response of HR and PE in the progressive effort test performed at two depths, umbilicus and xiphoid process, 2) Identify VO2max, [La]max, and PE for each AF system Evolution ® protocol in progressive loads and to predict the VO2. For study 1, the sample consisted of 10 active men and women who underwent two progressive tests, one in depth. For study 2, 15 men, physically active performed area submitted to 3 maximal tests, one each with AF and a test of submaximal constant workload to predict the caloric expenditure and power generated. In study 1, the maximum values of HR and PE showed no statistically significant differences when comparing the two depths. The HR for stage RPM, presented from the third stage tend to be higher in height of the xiphoid process. In study 2, there was no difference in the maximum values of HR, VO2, [La] and PE in 3 AF studied in maximal test, but the values occur at different rpm, showing that the higher the AF, the less RPM to achieve the maximum for HR, VO2, [La1] and PE. Since the study incremental load predicted VO2 from the variables AF, RPM. We conclude that the system Evolution ® aquatic bicycle Hidrocycle ® to tailor the exercise overload, as well as the prediction equity to facilitate the implementation of the equipment in the various areas of physical training.

A Síndrome Antifosfolípide (SAF) primária está associada com o risco aumentado de doenças cardiovasculares e mortalidade. A capacidade aeróbia e o controle autonômico cardíaco também estão associados a esses riscos. Objetivos: Avaliar a capacidade aeróbia e o controle autonômico cardíaco em pacientes com SAF primária. Métodos: Treze mulheres com SAF e treze controles saudáveis pareados por idade, sexo e índice de massa corporal foram incluídos no estudo. Ambos os grupos eram sedentários e não estavam em uso de medicações cronotrópicas, antidepressivas e hipolipemiantes. Todos os indivíduos realizaram o teste ergoespirométrico em esteira. A capacidade aeróbia foi avaliada através do pico do consumo de oxigênio (VO2pico), tempo no limiar anaeróbio ventilatório (LAV) e no ponto de compensação respiratória (PCR) e tempo no pico de esforço, enquanto o controle autonômico do coração foi avaliado através da reserva cronotrópica (RC) e frequência cardíaca na recuperação no primeiro e segundo minutos após o exercício (FCR1min e FCR2min, respectivamente). Resultados: Todos os índices de capacidade aeróbia estavam reduzidos nos pacientes com SAF primária em comparação com os controles saudáveis: VO2pico (30,2 ± 4,7 vs. 34,6 ± 4,3 mL.kg-1.min-1 P = 0,021), tempo no LA (3,0 ± 1,5 vs. 5,0 ± 2,0 min; P = 0,016), tempo no PCR (6,5 ± 2,0 vs. 8,0 ± 2,0 min; P = 0,050), tempo no pico de esforço (8,5 ± 2,0 vs. 11,0 ± 2,5 min; P = 0,010). As FCR1min (22 ± 9 vs. 30 ± 7 bpm; P = 0,032) e FCR2min (33 ± 9 vs. 46 ± 8 bpm; P = 0,002) foram menores nos pacientes com SAF em comparação com os controles saudáveis mas a RC não foi significativamente diferente (P = 0,272). Dessa forma, observamos uma diminuição na capacidade aeróbia e no controle autonômico nos pacientes com SAF
Primary antiphospholipid syndrome (PAPS) is associated with increased risk of cardiovascular disease and mortality. Aerobic capacity and cardiac autonomic control are also associated with these risks. Objective: To assess aerobic capacity and cardiac autonomic control in PAPS patients. Methods: Thirteen women with PAPS and 13 healthy controls matched for age, gender, and body mass index were enrolled for the study. Both groups were sedentary and were not under chronotropic, antidepressants and hypolipemiant drugs. All subjects performed a treadmill graded maximal exercise. Aerobic capacity was assessed by peak oxygen uptake (VO2peak), time at anaerobic ventilatory threshold (VAT) and respiratory compensation point (RCP), and time-to-exhaustion, whereas cardiac autonomic control by chronotropic reserve (CR) and heart rate recovery of the first and second minutes after graded exercise (HRR1min and HRR2min, respectively). Results: All aerobic capacity indexes were reduced in PAPS patients than healthy subjects: VO2peak (30.2 ± 4.7 vs. 34.6 ± 4.3ml.kg-1.min-1, P = 0.021), time at LAV (3.0 ± 1.5 vs. 5.0 ± 2.0 min, P = 0.016), time at RCP (6.5 ± 2.0 vs. 8.0 ± 2.0 min, P = 0.050), time-to-exhaustion (8.5 ± 2.0 vs. 11.0 ± 2.5 min, P = 0.010). HRR1min (22 ± 9 vs. 30 ± 7bpm, P = 0.032) and HRR2min (33 ± 9 vs. 46 ± 8bpm, P = 0.002) were delayed in PAPS patients compared to healthy controls but CR was not significantly different (P = 0.272). In conclusion, an impaired aerobic capacity and cardiac autonomic control was identified in PAPS

Os jogos de realidade virtual (JRV) são utilizados como estratégia complementar de reabilitação motora em indivíduos pós-acidente vascular cerebral (AVC). Porém, o impacto cardiovascular e metabólico desses jogos foi pouco investigado, o que é essencial para uma reabilitação completa. Com esse intuito, este estudo avaliou as respostas de frequência cardíaca (FC) e consumo de oxigênio (VO2) durante os JRV, comparando-as ao limiar anaeróbio (Lan) e ao ponto de compensação respiratória (PCR) e calculando o gasto energético (GE). Além disso, investigou-se as respostas da FC, pressão arterial (PA) e duplo produto (DP) no período pós-JRV e a reprodutibilidade de todas as respostas aos JRV. Para tanto, 12 indivíduos (84% homens, 56±12 anos) em fase crônica após um único AVC participaram, em ordem aleatória, de três sessões experimentais, sendo duas delas de JRV e uma controle. Nas sessões de JRV, os indivíduos foram submetidos a 4 blocos de jogos intercalados por 2 min de pausa; cada bloco foi composto por 3 min do jogo Tênis de Mesa, seguidos de 1 min de pausa e 4 min do jogo Boxe (Xbox360+Kinect). Na sessão controle, os indivíduos assistiram a um filme sentados por 38 min. A FC e o VO2 foram continuamente medidos durante as sessões, e a PA e FC foram medidas antes e aos 15 e 30 min após as intervenções. O GE foi calculado a partir do VO2. As respostas de FC e VO2 nos JRV tiveram boa reprodutibilidade (coeficiente de correlação intraclasse > 0,75 e baixo erro médio da medida). Os valores de FC medidos durante os JRV foram semelhantes ao Lan e significantemente inferiores ao PCR, com mais de 50% dos indivíduos apresentando FC abaixo do Lan em todos os JRV. O VO2 medido durante os JRV foi significantemente menor que o Lan e o PCR, com mais de 75% dos indivíduos com VO2 abaixo do Lan em todos os jogos. O GE médio da sessão de JRV foi de ? 4,6±0,1 kcal/min, totalizando 169±11 kcal. Após a sessão de JRV, a PA não se modificou, a FC e o DP permaneceram aumentados por 30 min. Conclui-se que, em indivíduos pós-AVC, a sessão de JRV proposta promoveu respostas fisiológicas reprodutíveis, que corresponderam a uma intensidade próxima e abaixo do Lan, gerando um GE médio de cerca de 4 kcal/min (3 METS) e mantendo o trabalho cardíaco aumentado por até 30 min após a sessão
Virtual reality games (VRG) has been used as a complementary strategy for motor rehabilitation in stroke survivors. However, the cardiovascular and metabolic impacts produced by these games has been poorly investigated, which is important for a complete rehabilitation. To investigate this impact, this study evaluated heart rate (HR) and oxygen consumption (VO2) responses during VRG, comparing these responses with anaerobic threshold (AT) and respiratory compensation point (RCP), and calculating the energy expenditure (EE). Furthermore, the responses of HR, blood pressure (BP) and rate pressure product (RPP) after the VRG session as well as the reproducibility of all the responses to VRG were evaluated. For that, 12 chronic post-stroke patients (84% men, 56±12 years) underwent, in random order, 3 experimental sessions: two composed by VRG and one control session. The VRG sessions were composed by 4 blocks of games interpolated by 2 min of rest, and each block was composed by 3 min of the table tennis game followed by 1 min of rest and 4 min of the boxing game (Xbox360+Kinect). In the control session, the subjects watched a film in the seating position for 38 min. HR and VO2 were continuously measured during the sessions, and HR and BP were also measured before and at 15 and 30 min after the interventions. EE was calculated from VO2. HR and VO2 responses to VRG showed good reproducibility (intraclass correlation index > 75% and low standard error of measurement). HR measured during the VRG was similar to AT and significantly lower than RCP, with more than 50% of the subjects presenting HR below AT in all the games. VO2 measured during the VRG was significantly lower than AT and RCP, with more than 75% of the subjects presenting VO2 below AT in all the games. VRG EE was ?4.6±0.1 kcal/min, totalizing 169±11 kcal. After the VRG session, BP did not change, while HR and RPP remained significantly increased up to 30 min. In conclusion, in post-stroke survivors, the proposed VRG session produced physiological responses that have good reproducibility and corresponded to an intensity near to and below the AT, generating a mean EE of 4 kcal/min (3 METs), and maintaining cardiac work elevated for at least 30 min after its end

Presence of left bundle branch block (LBBB), regardless of evidence of heart disease, increases cardiovascular mortality and morbidity. Isolated LBBB induces ventricular septal asynchrony, it can cause repercussions in left ventricular (LV) function and diameter, which may evolve into ventricular remodeling and heart failure. Cardiopulmonary exercise test (CPET) is a noninvasive diagnostic method and physiological, that simultaneously evaluates cardiovascular and respiratory functions, fundamental to understanding the mechanisms of exercise limitation.. This study sought to evaluate the implications of isolated LBBB to cardiovascular performance in patients with preserved LV systolic function and absence of myocardial ischemia. This is an observational, cross-sectional analysis, which evaluated 02 groups: LBBB (26 patients) and control (23 patients). All patients showed LV systolic function > 50% and myocardial ischemia was excluded through the physical stress echocardiography. They underwent CPET. At statistical analysis, we chose the general linear model, specifically multivariate analysis of covariance (MANCOVA) in which the dependent variables were the parameters of CPET and fixed factors were the LBBB and sedentary lifestyle. The results showed that the percentage of predicted peak oxygen pulse (O2P) in the LBBB group was 98.6 ± 18.6% versus 109.9 ± 13.5% (p = 0.02); the percentage of predicted peak oxygen consumption (VO2) in patients with LBBB was 87.2 ± 15.0% versus 105.0 ± 15.6% (p <0.0001); the percentage of predicted anaerobic threshold VO2 in LBBB group was 67.9 ± 13.6 % versus 70.2 ± 12.8% (p = 0.55); in the LBBB group, ΔVO2/Δwork rate was 15.5 ± 5.5 ml.min-1.watts-1 versus 20.7 ± 7.3 ml.min-1.watts-1 (p = 0.006); the VE/VCO2 slope in LBBB group was 29.8 ± 2.9 versus 26.2 ± 2.9 (p = 0.0001) and T1/2 VO2 was the LBBB group of 85.2 ± 11.8 seconds versus 71.5 ± 11.0 seconds (p = 0.0001). By MANCOVA, adjusting the intervention of sedentary lifestyle and covariates, it was showed that patients with LBBB with preserved left systolic function and absence of myocardial ischemia, showed increase in the VE/VCO2 slope, but the LBBB did not affect aerobic performance. Further studies are needed to elucidate whether the VE/VCO2 slope will be an earlier marker of ventricular dysfunction in patients with LBBB.
A presença de bloqueio do ramo esquerdo (BRE), independente da evidência de cardiopatia, está associado ao aumento da mortalidade e morbidade cardiovascular. O BRE isolado provoca assincronia do septo interventricular, causando repercussões nos diâmetros e na função do ventrículo esquerdo (VE), que podem progredir para o remodelamento ventricular e insuficiência cardíaca. O teste de esforço cardiopulmonar (TECP) é um método diagnóstico não invasivo e fisiológico, avalia simultaneamente as funções cardiovascular e pulmonar, permitindo entender melhor as causas da limitação ao exercício. O presente estudo buscou avaliar as implicações do BRE isolado no desempenho cardiovascular de pacientes com função sistólica do VE preservada e na ausência de isquemia miocárdica. Trata-se de um estudo observacional, transversal e analítico, que avaliou 02 grupos: BRE (26 pacientes) e controle (23 pacientes). Todos os pacientes apresentavam fração de ejeção do VE (FEVE) > 50%, pelo método Simpson e a pesquisa de isquemia do miocárdio foi realizada por meio da ecocardiografia sob estresse físico. Todos os pacientes foram submetidos ao TECP. Na análise estatística, optou-se pelo modelo linear geral, particularmente análise multivariada de covariância (MANCOVA), em que as variáveis dependentes foram os parâmetros do TECP e os fatores fixos foram o BRE e o sedentarismo. Os resultados revelaram que a percentagem atingida do pulso de oxigênio (PO2) pico predito no grupo BRE foi de 98,6 ± 18,6% versus 109,9 ± 13,5%, (p = 0,02); a percentagem do consumo de oxigênio (VO2) pico predito nos portadores de BRE foi de 87,2 ± 15,0% versus 105,0 ± 15,6% (p < 0,0001); a percentagem do VO2 predito limiar anaeróbico no grupo BRE foi de 67,9 ± 13,6 % versus 70,2 ± 12,8% (p = 0,55); o ΔVO2/Δcarga no grupo BRE foi de 15,5 ± 5,5 ml.min-1.watts-1 versus 20,7 ± 7,3 ml.min-1.watts-1(p = 0,006); a relação Ve/VCO2 slope no grupo BRE foi de 29,8 ± 2,9 versus 26,2 ± 2,9 (p = 0,0001) e o T1/2 VO2 no grupo BRE foi de 85,2 ± 11,8 segundos versus 71,5 ± 11,0 segundos (p = 0,0001). Através da MANCOVA, ajustando-se a intervenção do sedentarismo e das co-variáveis, mostrou-se que os portadores de BRE, com FEVE preservada e na ausência de isquemia miocárdica, apresentaram aumento do Ve/VCO2 slope, porém o BRE não provocou alteração da capacidade aeróbica. Novos estudos serão necessários para elucidar se o Ve/VCO2 slope será marcador precoce de disfunção ventricular nos portadores de BRE.

Abstract provided by Publisher Complex performance diagnostics in sports medicine should contain maximal aerobic and maximal anaerobic performance. The requirements on appropriate stress protocols are high. To validate a test protocol quality criteria like objectivity and reliability are necessary. Therefore, the present study was performed in intention to analyze the reliability of maximal lactate production rate (VLamax) by using a sprint test, maximum oxygen consumption (VO2max) by using a ramp test and, based on these data, resulting power in calculated maximum lactate-steady-state (PMLSS) especially for amateur cyclists. All subjects (n=23, age 26 ± 4 years) were leisure cyclists. At three different days they completed first a sprint test to approximate VLamax. After 60 min of recreation time a ramp test to assess VO2max was performed. The results of VLamax-test and VO2max-test and the body weight were used to calculate PMLSS for all subjects. The intra class correlation (ICC) for VLamax and VO2max was 0.904 and 0.987, respectively, coefficient of variation (CV) was 6.3 % and 2.1 %, respectively. Between the measurements the reliable change index of 0.11 mmol∙l-1∙s-1 for VLamax and 3.3 ml∙kg-1∙min-1 for VO2max achieved significance. The mean of the calculated PMLSS was 237 ± 72 W with an RCI of 9 W and reached with ICC = 0.985 a very high reliability. Both metabolic performance tests and the calculated PMLSS are reliable for leisure cyclists.

Kardiovaskularni odgovor na različite fiziološke stimuluse moguće je pratiti putem analize razlika utrajanju srčanih ciklusa – varijabilnosti srčane frekvencije (VSF). Ona ima široku primenu u oblasti sporta budući da je monitoring putem VSF krajnje bezbedan, jeftin i jednostavan za izvođenje. Njeni indeksi se razlikuju između treniranih i netreniranih, uvećavaju se u odgovoru na trening izdržljivosti, a padaju ukoliko dođe do pojave zamora i pretreniranosti. Cilj istraživanja je bio da se utvrdi da li postoji razlika između sportista iz grupe dominantno anaerobnih sportova (AN), sportista iz grupe dominantno aerobnih sportova (AE) i nesportista (NS) u VSF u miru i u autonomnom odgovoru nakon testova za ispitivanje aerobnog i anaerobnog energetskog kapaciteta, kao i da li postoji povezanost između rezultata ovih testova i parametara VSF unutar grupa. Ispitivanju je pristupilo 75 sportista koji su zatim razvrstani na osnovu dominantnih metaboličkih zahteva treniranog sporta tako da ih je u AN grupi bilo 36 (20.7±2.4 god., 1.83±0.07 cm, 83.5±12.3 kg), a u AE grupi 39 (20.5±1.9 god., 1.79±0.06 cm, 75.6±8.1 kg). U NS grupi bilo je 39 ispitanika (21.4±1.8 god., 1.82±0.06 cm, 83.1±11.2 kg) iste uzrasne dobi i sličnih demografskih karakteristika sa sportistima. Ispitanici su u različitim danima bili podvrgnuti anaerobnom Vingejt testu (WanT) i inkrementalnom testu za određivanje maksimalne aerobne potrošnje (VO₂max). VSF je registrovana Polar pulsmetrom, a podaci su obrađeni u Polar ProTrainer 5 softveru. Sportisti iz AE grupe imali su više vrednosti parametara SDNN (standardna devijacija NN intervala (interval između R zubca jednog do R zubca narednog, normalnog QRS kompleksa)) i RMSSD (kvadratni koren srednje vrednosti sume kvadrata razlika) merene u mirovanju u odnosu na ostale grupe. Razlike u VSF između grupa tokom oporavka od WanT i VO₂max testa nije bilo. U AN grupi parametar SDNN umereno negativno je korelirao sa vrednostima prosečne snage (eng. mean power, MP) i maksimalne snage (eng. peak power, PP) u VSF u miru i tokom oporavka od WanT. Parametar lnLF (prirodni logaritam vrednosti niskofrekventnog opsega spektra) pokazivao je istovetnu korelaciju u miru sa MP i PP, a tokom oporavka od Want umereno negativno je korelirao samo sa vrednosti PP. Parametar VSF u miru – lnHF (prirodni logaritam vrednosti visokofrekventnog opsega spektra) umereno negativno je korelirao sa MP. Odnos niskofrekventnog prema visokofrekventnom opsegu spektra (LF/HF) pokazivao je umerenu pozitivnu povezanost sa vrednosti maksimalne snage prema kilogramima telesne teţine (PP/kg) i u miru i tokom oporavka od WanT. U AE i NS grupi nisu uočene povezanosti sa rezultatima WanT u miru i oporavku. Kod AE sportista u miru vrednost prosečnog NN intervala (NNRR) umereno pozitivno je korelirala sa vršnom vrednošću VO₂ (VO₂ pik), a umerena negativna povezanost ispoljena je za vrednost maksimalnog broja otkucaja na kraju VO₂max testa (HRmax) sa SDNN, SD1 (kratkoročna varijabilnost Poenkareovog zapleta), RMSSD, pNN50 (procentualni udeo NN intervala duţih od 50 ms u ukupnom broju NN intervala), ukupnom snagom spektra (TP), vrednosti opsega spektra vrlo niskih frekvencija (VLF), vrednosti niskofrekventnog opsega spektra (LF), lnLF, vrednosti visokofrekventnog opsega spektra (HF) i lnHF. Umerena negativna korelacija postojala je i za vrednost srčane frekvencije na ventilatornom pragu (HRvt) sa vrednostima SDNN, SD1 i RMSSD. Tokom oporavka od VO₂max testa kod ovih sportista postojala je umerena negativna povezanost vrednosti VO₂pik sa lnHF, vrednosti visokofrekventnog opsega spektra izraženu u normalizovanim jedinicma (HFnu) i LF/HF, a VO₂pik je i umereno pozitivno korelirao sa HF. U NS grupi naglašeni parasimpatički (PNS) markeri VSF (NNRR i pNN50) u miru dovođeni su u negativnu vezu sa progesijom srčanog ritma tokom VO₂max testa, a dominacija u niskofrekventnom opsegu spektra bila je u direktnom odnosu sa ostvarenim vršnim vrednostima VO₂. U aerobnim sportovima u VSF u miru dominiraju PNS obeležja. Niska VSF u miru i u uslovima oporavka od WanT karakteristika je sportista iz anaerobne grupe sportova. Naglašenost pojedinih PNS markera u miru i uslovima oporavka od VO₂max testa moguće ukazuje na bolji aerobni kapacitet u sportovima izdržljivosti. Među nesportistima bolju aerobnu izdržljivost imaju oni kod kojih u miru postoji dominacija u niskofrekventnom opsegu spektra.
Cardiovascular response to various physiological stimuli is possible to monitor through heart cycle length analysis – heart rate variability (HRV). HRV has a vast application in sport concerning that monitoring via HRV is absolutely safe, cheap and simple for use. HRV indexes are different among trained and untrained subjects, they are augmented in response to endurance training and lowered in the case of fatigue and overtraining. The goal of this research was to determine if there is a difference between athletes from dominantly anaerobic sports (AN), athletes from dominantly aerobic sports (AE) and non-athletes (NA) in resting HRV and in autonomic response after tests for determination of anaerobic and aerobic capacity, and also to examine if there is a correlation of results of these tests and HRV parameters intra-group. The research included 75 athletes who were classified in two groups according to the dominant metabolic demands of the trained sport – the AN group consisted of 36 athletes (20.7±2.4 yrs, 1.83±0.07 cm, 83.5±12.3 kg), and the AE group consisted of 39 athletes (20.5±1.9 yrs, 1.79±0.06 cm, 75.6±8.1 kg). In the NA group there were 39 participants (21.4±1.8 yrs,1.82±0.06 cm, 83.1±11.2 kg) who were of same age and similar demographic characteristics as athletes. The examinees were subjected to anaerobic Wingate test (WanT) and incremental test for maximal aerobic expenditure (VO₂max) in different days. HRV was registered with Polar heart rate monitor and the data were analyzed in Polar Pro Trainer 5 software. Athletes from AE group had higher values of resting SDNN (standard deviation of NN intervals (normal-to-normal intervals – intervals from the peak of one R wave to the peak of subsequent R wave of normal QRS complexes) and RMSSD (root mean square of the successive squared differences) in regard to other two groups. We did not find any differences in HRV between groups during the recovery from WanT and VO₂max test. SDNN parameter correlated moderately negatively with mean power (MP) and peak power (PP) in rest and during recovery from WanT in AN group. The natural logarithm of low frequency spectral band (lnLF) showed the same type of correlation in rest with MP and PP, and it correlated moderately negatively with PP in recovery from WanT. The resting HRV parameter – lnHF (natural logarithm of high frequency spectral band) moderately negatively correlated with MP. The low frequency spectral band to high frequency spectral band relation (LF/HF) showed moderately positive correlation with PP in respect to kilograms of body weight (PP/kg) in rest and during recovery from WanT. In AE and NA group no correlations were seen with the results of WanT in HRV at rest and during recovery. In AE group resting NNRR (average NN interval) moderately positively correlated with peak VO₂ value(VO₂peak), and moderate negative correlation existed for maximal heart rate at the end of VO₂max test (HRmax) with SDNN, SD1 (short time variability of Pointcare plot), RMSSD, pNN50 (the percentage of NN intervals longer than 50 ms in overall number of NN intervals), total spectral power (TP), very low frequency spectral power (VLF), low frequency spectral power (LF), lnLF, high frequency spectral power (HF) and lnHF. Moderate negative correlation existed for heart rate at ventilatory treshold (HRvt) with the values of SDNN, SD1 and RMSSD. During recovery from VO₂max test athletes from AE group had moderately negative correlation of VO₂peak with lnHF, high frequency spectral power expressed in normalized units (HFnu) and LF/HF, аnd VO₂peak did moderately positively correlate with HF. In NA group augmented resting parasympathetic HRV markers (NNRR and pNN50) were in negative relation with heart rate progression during VO₂max test, and a dominance in low frequency spectral band was in direct relation with achieved values of VO₂peak. In aerobic sports PNS tone is marked. Reduced HRV in rest and during the recovery from WanT is seen in athletes from anaerobic sports. Augmentation of some PNS parameters in rest and recovery conditions from VO₂max test possibly suggests better aerobic capacity in endurance sports. Among non-athletes better aerobic endurance was reserved for the ones who showed dominance in low frequency spectral band in resting-state HRV.

Abstract PO2 DEPENDENCE OF OXYGEN CONSUMPTION IN SKELETAL MUSCLE OF DIABETIC AND NON-DIABETIC RATS By: Alexander C. Liles A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science at the Medical College of Virginia Campus, Virginia Commonwealth University Virginia Commonwealth University, 2017 Advisor: Roland N. Pittman, Ph.D. Department of Physiology and Biophysics Type 2 diabetes mellitus (T2DM) is a major medical problem around the world, affecting nearly 6% of the world’s population. This study was an attempt to better understand physiological changes the disease may cause to the microcirculation and more specifically, to assess the dependence of oxygen consumption in skeletal muscle of a diabetic animal model. The spinotrapezius muscles of Goto-Kakizaki (G-K) and Wistar control rats were used to measure interstitial using phosphorescence quenching microscopy. The G-K rats spontaneously develop T2DM and serve as an appropriate model for the disease in humans. By rapidly arresting blood flow in the tissue and observing the resulting changes, an oxygen disappearance curve (ODC) was created. The ODC was used to calculate oxygen consumption rate (VO2) over the physiological range of PO2 values. The resulting VO2 vs PO2 curves were analyzed using Hill’s equation to fit the data and obtain values of several key parameters to quantitatively describe the PO2 dependence of oxygen consumption. When compared to healthy control rats, the G-K rats exhibited a significantly higher Vmax, or maximum rate of oxygen consumption, compared to the Wistar rats. The two rat sub-strains had similar values for P50, which indicates the PO2 at half maximal consumption. The overall higher maximal rate of consumption by the diseased animals could be explained by some disconnect in the consumption of oxygen by the mitochondria and the normal corresponding production of ATP. In conclusion, it was demonstrated that in situ muscle tissue from both diabetic and non-diabetic rats had a PO2 dependence of oxygen consumption over a wide range of PO2 values and the muscles of diabetic animals consumed oxygen at a higher maximal rate.

Using a high throughput closed respirometry method to measure oxygen consumption, I determined metabolic rates in asexual and sexual Schmidtea mediterranea and Girardia dorotocephala, as a function of temperature, taxon, stressors, reproductive mode, age, regeneration, and specific dynamic action. This study has shown that oxygen consumption can reliably be measured in planaria using optode closed respirometry, and also provided a reliable method for measuring wet mass in planaria, which has been a challenge to researchers in the past. This research revealed that oxygen consumption in S. mediterranea is 1.5-2.1X greater in the sexual strain over the asexual strain at 13-18°C. Within the sexual strain, oxygen consumption is 1.5 -2.2X greater in sexually mature adults over the sexually immature groups (hatchlings, juveniles, and regenerating sexuals). Furthermore, I was able to quantify differences in sexual morphology between these groups exhibiting significant differences in oxygen consumption. The results of this research supports a theory of higher metabolic costs with sexual maturity in S. mediterranea. Therefore, this study has established sexual and asexual S. mediterranea as simple, yet attractive models for investigating energetic costs between sexual and asexual phenotypes. This research also provided quantitative values for specific dynamic action in planaria, with a maximum increase in oxygen consumption of 160% induced by feeding, as well as metabolic relationships in planaria involving temperature, age, and regeneration. These values establish planaria as one of the simplest animal models in which common metabolic patterns, such as SDA and poikilothermic temperature sensitivity, have been demonstrated. Therefore, this research has contributed to the overall knowledge of the basic physiology in this animal, providing the framework for future metabolic studies in planaria involving environmental factors, reproduction, regeneration, development, and aging. Information from this study may supplement interpretation and understanding of modern cellular, molecular, and genomic studies in planaria.

Human essential hypertension affects over 75 million people in the United States, and can lead to death due to its several serious health complications such as hypertension-related cardiovascular disease. The purpose of this research was to understand how hypertension could cause physiological changes to the microcirculation, specifically the PO2 dependence of oxygen consumption (VO2) in skeletal muscle of normotensive and hypertensive rats. The Spontaneously Hypertensive Rat (SHR) strain was used as the diseased model, and Wistar-Kyoto (WKY) rats were used as controls to conduct this study. The SHR strain develops hypertension between 5-6 weeks after birth with an average systolic blood pressure of 150 mmHg. By arresting blood flow using an objective-mounted inflatable airbag, PO2 measurements were obtained along with an oxygen disappearance curve (ODC), which was used to calculate VO2 over various ranges of physiological PO2 values. PO2 and VO2 curves were analyzed based on Hill’s equation to fit the data and describe the PO2 dependence of VO2. When compared to the healthy Wistar-Kyoto rats, the SHRs exhibited a higher Vmax, or maximum rate of oxygen consumption. The average maximal rate of consumption by the hypertensive animal models could be a consequence of a “mitochondrial uncoupling” or some disconnect in the mitochondrial oxygen consumption and the normal corresponding ATP production. In conclusion, this project demonstrated that in situ muscle tissue from hypertensive and normotensive rats had a PO2 dependence of oxygen consumption over a wide range of physiological PO2 values and the hypertensive rats consumed oxygen at a higher maximal rate.

Alzheimer’s disease (AD) is the most common neurodegenerative disorder and the most frequent form of dementia in developed countries, which leads to severe loss of memory and cognitive dysfunctions. By far, the majority of AD cases are sporadic (SAD), with unknown etiology, for which the main risk factors are represented by aging and by the presence of the allelic variant APO-e4 of apolipoprotein E. Only a small but significant percentage of cases, collectively called familial AD (FAD), is inherited and is caused by autosomal dominant mutations in the genes coding for the amyloid precursor protein (APP), presenilin 1 (PS1) and presenilin 2 (PS2) respectively. APP is a single transmembrane domain protein with a large extracellular domain, expressed at high level in the brain. PSs are homologous membrane proteins specially localized in the endoplasmic reticulum (ER) and Golgi apparatus; they represent the essential components of the gamma-secretase complex, which, by cleaving APP in concert with beta-secretase, leads to the production of the neurotoxic beta-amyloid peptides. The identification of these genetic factors involved in FAD cases, allowed the development of transgenic mouse models. Given that SAD and FAD cases are morphologically and clinically similar, these models represent an important research tool to investigate potential common molecular mechanisms between the two AD forms, with the aim of devising effective therapies. In these studies, two transgenic mouse models were used to perform the experiments. The first one is a single transgenic line, homozygous for the FAD-linked PS2-N141I mutation, which is under the prion promoter control and it is ubiquitously expressed. The second model is a double transgenic line homozygous for both the FAD-linked PS2-N141I mutation and APPSwe mutation, which is under Thy.1 promoter control, thus expressed only in neurons. We investigated the possible, early impairment of mitochondrial functions in the brain of the transgenic animals. Mitochondria are cytoplasmic organelles responsible for most of the energy supplied to the cells through ATP production; furthermore, they are involved in many other roles, such as Ca2+ homeostasis, reactive oxygen species production (ROS) and apoptosis. It is well established that mitochondrial impairment contributes to normal aging and to a wide spectrum of age-related diseases, including neurodegenerative diseases, such as AD, Parkinson’s Disease (PD), Amyotrophic Lateral Sclerosis (ALS), and Huntington’s Disease (HD). First of all, we started with mitochondria isolated from the brain of WT, single and double transgenic mice of different ages, from neonatal up to 2 years old animals, to investigate the age-dependent progression in the onset of potential mitochondrial dysfunctions. We evaluated mitochondrial bioenergetics parameters such as the oxygen consumption rate (OCR), the membrane potential and the calcium retention capacity (CRC). These experiments didn’t reveal overt defects in the respiratory complexes activity or in the sensitivity of the permeability transition pore (PTP) to matrix Ca2+ overload in transgenic animals compared to WT, suggesting that these FAD-linked mutations do not cause severe primary defects on the organelles. Isolated mitochondria represent a useful tool in many instances, but being removed from the cellular environment do not allow the study of the complex interaction that mitochondria entertain with other organelles or components of the cell. For this reason, we decided to study mitochondria in primary hippocampal cultures, specifically because the hippocampus is one of the first and main affected brain areas in AD. In the context of intact cells, the basal respiration and the ATP synthesis coupled respiration measured by the mean of the Extracellular Flux Analyzer (Seahorse) didn’t show significant differences among the three genotypes, whereas the maximal respiration was significantly higher in WT neurons compared to PS2APP neurons, suggesting a possible impairment in the supply of substrates to mitochondria. Measuring the ability of mitochondria to sustain the membrane potential upon the selective inhibition of either the respiratory chain or the ATP synthase suggested the presence of a possible defect in the latter enzyme, in its ability to hydrolyze ATP, or the presence of an unknown metabolic defect/s limiting the supply of ATP to the synthase to sustain its reverse activity. Despite these interesting data obtained in hippocampal neurons, we didn’t observe the same strong differences under similar conditions in experiments performed in human fibroblast carrying the same FAD-linked PS2 mutation. These differences could be due to the fact that fibroblasts are mostly glycolytic cells, which might be less affected than neurons by mitochondrial dysfunctions. In order to check the ATP synthase reverse activity, we measured NADH oxidation in isolated mouse brain-cortex mitochondria. The preliminary results showed a higher ATP hydrolysis rate in PS2 and PS2APP mitochondria compared with WT, but more experiments are needed to assess the statistical significance of this finding. Blocking the respiratory chain, or the ATP synthase, in neuronal cells, so likely impairing ATP production, didn't show any major difference in the ability of the cells to handle potentially threatening increased cytosolic calcium concentration, [Ca2+]c. This evidence prompted the conclusion that under these experimental conditions, neurons seem to be equally able to handle a decrease in ATP content, and perhaps prolonged and stronger stimuli would be necessary to disclose possible defects. Moreover, the basal ROS production in these cells is very low and seems to be similar among the genotypes. Given the results collected so far, it would be interesting to better clarify the activity of the ATP synthase in the transgenic animals and investigate further the metabolic cross-talk between mitochondria and the rest of the cell.
Il morbo di Alzheimer è la malattia neurodegenerativa più diffusa e una delle principali cause di demenza nei paesi occidentali. Questa patologia determina progressivi danni alla memoria e ad altre importanti funzioni cognitive. La maggior parte dei casi di Alzheimer è sporadica, compare in tarda età e i fattori di rischio più conosciuti sono l’invecchiamento e la variante allelica APO-e4 del gene che codifica per la lipoproteina E. Esiste tuttavia una piccola ma significativa percentuale di casi ereditari (forma familiare di Alzheimer, FAD) che è causata da mutazioni autosomiche dominanti in tre geni che codificano per la Proteina Precursore dell’Amiloide (APP), per la Presenilina-1 (PS1) e la Presenilina-2 (PS2). L’APP è una proteina transmembrana espressa principalmente nel cervello. Le preseniline sono proteine omologhe di membrana presenti soprattutto nel reticolo endoplasmatico e nell’apparato di Golgi. Costituiscono ciascuna, indipendentemente, la parte catalitica dell’enzima gamma-secretasi che, insieme all’enzima beta-secretasi, è responsabile del taglio dell’APP e della conseguente formazione di peptidi Abeta, molto dannosi per il cervello. L’identificazione di mutazioni genetiche coinvolte nelle forme familiari di Alzheimer, ha permesso lo sviluppo di modelli di topi transgenici. Dato che i casi sporadici e quelli familiari della malattia sono clinicamente molto simili, questi modelli rappresentano uno strumento essenziale per la ricerca, poiché permettono lo studio di possibili meccanismi molecolari condivisi e danno la possibilità di scoprire/migliorare eventuali terapie. In questo progetto, gli esperimenti sono stati effettuati utilizzando due modelli transgenici di topi disponibili in laboratorio. Il primo è un topo transgenico omozigote per la mutazione PS2-N141 che è stata posta sotto il controllo del promotore prionico e quindi viene espressa in tutti i tessuti. Il secondo modello è omozigote per la stessa mutazione di PS2 e anche per una mutazione dell’APP (APPSwe) che si trova sotto il controllo del promotore Thy.1, ed è quindi espressa solo nel cervello. L’obiettivo di questo studio è quello di trovare possibili danni precoci nei mitocondri di cervello in questi modelli transgenici di Alzheimer. I mitocondri sono organelli citoplasmatici principalmente coinvolti nel fornire energia alla cellula sotto forma di ATP, ma sono in realtà indispensabili per molte altre funzioni, come ad esempio il controllo dell’omeostasi del calcio, la produzione delle specie radicali di ossigeno (ROS) e l’apoptosi. Al giorno d’oggi, è ampiamente accettato che danni a questi organelli non sono solo presenti durante il normale invecchiamento ma anche in molte altre malattie legate ad esso, comprese le malattie neurodegenerative come l’Alzheimer, il morbo di Parkinson, la sclerosi laterale amiotrofica e la corea di Huntington. I primi esperimenti sono stati effettuati in mitocondri isolati dal cervello dei topi WT, PS2 e PS2APP, partendo da quelli di 8 giorni fino a topi di 2 anni, per documentare la possibile presenza e/o progressione di disfunzionalità dei mitocondri. Abbiamo valutato diversi parametri bioenergetici, come la velocità di consumo dell’ossigeno (oxygen consumption rate, OCR), il potenziale di membrana mitocondriale e la capacità dei mitocondri di accumulare calcio nella matrice (calcium retention capacity, CRC). I risultati di questi esperimenti non hanno tuttavia rivelato particolari differenze tra i topi WT e quelli transgenici, né per quanto riguarda l’attività dei complessi della catena respiratoria, né per la sensibilità del poro di transizione della permeabilità mitocondriale (permeability transition pore, PTP) ad un elevato aumento di Ca2+ nella matrice. Tali dati suggeriscono che probabilmente, queste mutazioni FAD non inducono direttamente danni ai mitocondri. I mitocondri isolati sono uno strumento molto utile per studiare le caratteristiche e la funzionalità di questi organelli, ma presentano tuttavia alcuni svantaggi: per esempio, in queste condizioni il mitocondrio è separato dal suo ambiente fisiologico e non è così possibile studiare le sue interazioni con le altre componenti del citoplasma. Per questo motivo, abbiamo deciso di spostare la nostra attenzione sulle colture primarie neuronali di ippocampo, perché quest’area del cervello è una delle regioni maggiormente e precocemente colpite dall’Alzheimer. Per prima cosa, abbiamo comparato la respirazione basale e la respirazione accoppiata alla sintesi di ATP misurate con l’Extracellular Flux Analyzer (Seahorse) senza però trovare differenze significative tra le colture dei tre genotipi. La misura della respirazione massima è invece più alta nei WT rispetto a PS2 e PS2APP, e la differenza è significativa tra WT e PS2APP, suggerendo una possibile alterazione nel rifornimento di substrati ossidabili ai mitocondri. In seguito, le misure effettuate per valutare la capacità dei mitocondri di mantenere il potenziale di membrana dopo l’inibizione selettiva dei complessi della catena respiratoria o dell’ATP sintasi, hanno rivelato un possibile difetto in quest’ultima, che potrebbe limitare la capacità di idrolizzare l’ATP, oppure alla presenza di difetti metabolici sconosciuti che limitano il rifornimento di ATP del citoplasma per sostenere l’attività idrolitica. Visti questi risultati, abbiamo provato a ripetere gli esperimenti in fibroblasti provenienti da pazienti caratterizzati dalla stessa mutazione di PS2 presente nei modelli transgenici di topo. In questo caso però, la differenza tra fibroblasti provenienti da controlli sani e quelli provenienti dai pazienti non è così marcata come quelli emersi dagli studi nelle colture neuronali primarie. Questo può essere spiegato dal fatto che i fibroblasti sono cellule molto diverse dai neuroni, potrebbero ad esempio utilizzare di più la glicolisi, o semplicemente potrebbero risentire meno dell’effetto della mutazione in PS2. Per verificare se effettivamente potesse esserci un difetto a livello dell’attività idrolitica dell’ATP sintasi, abbiamo provato a misurare indirettamente la velocità di idrolisi dell’ATP in mitocondri isolati da cervello di topi dei tre genotipi tramite l’ossidazione del NADH. Al momento, sembra che la velocità di idrolisi sia più veloce nei transgenici, anche se il numero di esperimenti non è ancora sufficiente per stabilire se tale differenza sia significativa o meno. Abbiamo inoltre verificato che bloccando la catena respiratoria o l’ATP sintasi, di fatto diminuendo la quota di ATP prodotto dai mitocondri, i neuroni WT, PS2 e PS2APP sono ugualmente in grado di regolare il calcio citosolico. Questo suggerisce che in queste condizioni sperimentali i neuroni sono in grado di sopperire alla riduzione dell'ATP e che probabilmente per evidenziare delle differenze tra i genotipi bisognerebbe utilizzare uno stimolo più forte o prolungato. Un altro parametro verificato è la produzione di ROS, che in condizioni basali è molto basso e che sembra essere simile tra i genotipi. Dati i risultati ottenuti fino ad adesso, sarebbe interessante studiare nel dettaglio l’attività dell’ATP sintasi che potrebbe essere alterata nei modelli transgenici e soprattutto potrebbe essere interessante studiare le interazioni metaboliche tra i mitocondri e il resto della cellula.

L'objectif de ce travail est d'étudier les adaptations cardio-respiratoires, métaboliques et hormonales des joueurs et joueuses de tennis au laboratoire et sur le terrain. Au laboratoire : cent joueurs et 76 joueuses réalisent une épreuve d'effort d'intensité maximale afin de déterminer leur aptitude maximale aérobie (vo#2max) ; parmi eux, 32 sujets bénéficient d'une détermination de leur seuil anaérobie lactique et 73 jeunes joueurs effectuent un test charge vitesse. Les résultats montrent que : -la pratique du tennis nécessite non seulement une bonne puissance maximale aérobie mais aussi un haut niveau d'endurance. - les jeunes développent au niveau des membres inférieurs des puissances instantanées élevées et leurs qualités musculaires de vitesse prédominent sur la force. Sur le terrain : neuf jeunes joueuses et 10 joueuses vétérans effectuent un match avec enregistrement en continu de la fréquence cardiaque et une mesure au début et à la fin du match du ionogramme plasmatique, de la glycémie des concentrations plasmatiques des acides gras libres, de l'acide lactique, des catécholamines, de l'arginine vasopressine et de l'activité rénine plasmatique. Les résultats montrent que chez les vétérans, la sollicitation cardiaque devient de plus en plus importante au fur et à mesure que le match se prolonge. Seules les joueuses vétérans présentent une diminution de leur volume plasmatique. En fin de match, les concentrations des ions sont peu modifiées à l'exception du phosphore qui augmente. L'acide lactique augmente peu, les agl augmentent ainsi que la glycémie. L'activité rénine plasmatique, l'arginine-vasopressine, la noradrénaline augmentent alors que l'adrénaline ne varie pas. De plus, 10 joueurs réalisent un match avec mesure simultanée de la fréquence cardiaque, de la ventilation et de la consommation d'oxygène, grâce à un appareil de télémétrie portable. Les résultats montrent que la consommation d'oxygène atteint une valeur correspondant à 55% de la vo#2 max des joueurs. Les valeurs de vo#2 fluctuent très rapidement. Leur évolution est parallèle a celle de la fréquence cardiaque. En dépit du caractère intermittent de cette activité, la fréquence cardiaque mesurée sur le terrain parait constituer un bon reflet de la consommation d'oxygène des joueurs.

Introdução: a revisão de literatura aponta que os recém-nascidos submetidos ao banho de imersão produzem menor variação térmica pós-banho comparado aos submetidos ao banho com esponja. No Brasil, o Ministério da Saúde vem capacitando profissionais que atuam em unidades de internação neonatal para implementar o Método Mãe Canguru e, entre outras práticas, recomenda que o recém-nascido pré-termo (RNPT) e com baixo peso seja submetido ao banho de imersão envolto em cueiro ou lençol, sugerindo mudança da prática hegemônica do banho com esponja ou banho de imersão convencional. No entanto, a técnica de banho de imersão recomendada carece de evidências científicas quanto a sua segurança em relação às repercussões na estabilidade da temperatura corporal (T), frequência cardíaca (FC), cortisol salivar (CS) e comportamental em RNPT. Hipótese: os RNPT submetidos ao banho de imersão envoltos em lençol (BIE) apresentam respostas fisiológicas e comportamentais similares aos submetidos à técnica de banho de imersão convencional (BIC), nos primeiros 20 minutos pós-banho. Objetivo: avaliar os parâmetros fisiológicos e comportamentais de RNPT submetidos ao banho de imersão envolto em lençol (BIE) e banho de imersão convencional (BIC). Método: ensaio clínico randomizado cruzado com amostra composta por 43 RNPT, internados na Unidade Neonatal de um hospital escola da cidade de São Paulo. Os RNPT foram alocados no grupo A ou B, seguindo uma lista de randomização gerada pelo software R que foi envelopada e mantida com os auxiliares da pesquisa responsáveis pelos banhos dos RNPT. A randomização definiu a técnica do primeiro banho que o RN seria submetido. Somente após análise dos dados foi aberto o envelope da randomização sendo identificado que no grupo A, o primeiro banho foi o BIC (intervenção controle) e no grupo B, o BIE (intervenção experimental). A técnica do BIE seguiu a técnica recomendada no Manual Atenção Humanizada ao Recém-Nascido de Baixo Peso: Método Mãe-Canguru, publicada pelo Ministério da Saúde. Foram utilizadas filmadoras para obter os valores da FC e da SatO2 registradas pelo monitor cardíaco instalado nos RNPT e para captar imagens das reações comportamentais antes e após os banhos. As temperaturas axilares foram aferidas com termômetro digital e amostras de saliva foram coletadas com esponja oftálmica (Merocel)®, refrigeradas e processada pelo teste Elisa. As filmagens do estado comportamental 10 minutos pré e 10 e 20 minutos pós-banho foram analisadas utilizando o instrumento de avaliação do sono-vigília validado por Brandon e Holditch-Davis. Os dados foram registrados em formulário próprio e armazenados em planilha Microsoft Excel. A análise estatística foi realizada com os programas Minitab, versão 16.1 e SPSS, versão 20. Além da análise descritiva das variáveis numéricas para obtenção de medidas de tendência central e dispersão e frequências absoluta e relativa, foram utilizados os testes Qui-quadrado e Exato de Fisher; o teste T pareado, ANOVA e Modelos Generalizados Lineares na análise dos dados. Resultados: As temperaturas axilares médias dos RNPT pré-BIC e pré-BIE foram, respectivamente, 36,695°C e 36,667°C, p = 0,329. No 10° minuto pós-BIC e BIE, as médias das temperaturas axilares foram, respectivamente, 36,533°C e 36,535°C, p = 0,944. No 20° minuto pós-BIC e BIE, as médias da temperatura axilar foram 36,626°C e 36,628°C, p = 0,663. Houve queda na temperatura axilar no 10° minuto pós-banho, independente do tipo de banho realizado (p <0,001). A hipótese de que o BIE é equivalente ao BIC em relação à variação da temperatura axilar foi confirmada. Houve redução significante nos valores das FC no 10° e 20° minutos pós-BIC e BIE comparados aos valores pré-banho, independente do tipo de banho (p<0,001). Ocorreu aumento gradativo dos valores médios de SatO2 no 10º e 20° minutos após os banhos sem diferenças significantes nos valores pré-banhos, p = 0,969. A concentração do cortisol salivar aumentou após o banho em ambos os grupos, p = 0,001, entretanto não ocorreram diferenças entre os grupos, ou seja, os níveis de cortisol salivar aumentaram após o banho, independente do tipo de banho, p = 0,797. O percentual de tempo em estado sono ativo aumentou após o banho, independente do tipo de banho, p<0,001, ou seja, houve mudança significativa no comportamento do recém-nascido, sem diferenças entre os banhos, p = 0,425. Conclusão: Tanto os RNPT que receberam BIC quanto os que receberam BIE apresentaram queda na temperatura corporal no 10° minuto pós-banho com aumento da temperatura corporal no 20° minuto pós-banho. Comparado aos achados da literatura, a redução da temperatura corporal foi menor que no banho com esponja. O BIE é equivalente ao BIC, portanto ambos são indicados aos RNPT. Convêm salientar o aumento dos custos do BIE em razão do consumo de lençol e da capacitação necessária da equipe de enfermagem nesta técnica de banho, sem prolongar o tempo médio dispendido no banho, visto que poderá reduzir a temperatura da água do banho e consequentemente causar queda na temperatura corporal do RN.
Introduction: the literature review shows that newborns underwent to immersion baths produce less post-bath thermal variation compared to those underwent to the sponge bath. In Brazil, the Ministry of Health has been qualifying working professionals in neonatal hospitalization units to implement the Kangaroo Mother Care and, among other practices, recommends that the preterm newborn infants (PNI) and underweight are underwent to the swaddle immersion bath wrapped in clothes or sheet, suggesting change of the hegemonic practice of sponge bath or conventional immersion bath. However, the immersion bath technique recommended requires more scientific evidence about its safety in relation to impact on the stability of body temperature (T), heart rate (HR), salivary cortisol (SC) and behavioral in PNI. Hypothesis: PNI underwent to swaddle immersion bath wrapped in sheet (SIB) have physiological and behavioral responses similar to those underwent to the conventional immersion bath technique (CIB), in the first 20 minutes post-bath. Objective: To evaluate the physiological and behavioral parameters of preterm newborn infants underwent to swaddle immersion bath in sheet (SIB) and conventional immersion bath (CIB). Method: Randomized crossover clinical trial with a sample of 43 preterm newborn infants in the neonatal unit of a university hospital in the city of Sao Paulo. PNI were allocated in the A or B groups, following a randomization list which was generated by the software R, which was enveloped and maintained with research assistants who were responsible for the baths of PNI. Randomization list defined the first bath technique that the newborn was underwent. The randomization envelope was only opened after data analysis being identified that in group A, the first bath was the CIB (control intervention) and group B, the SIB (experimental intervention). The SIB technique followed the technique recommended in the Humane Care Infant, Low Birth Weight: Kangaroo Mother Care Manual, published by the Ministry of Health of Brazil. Video cameras were used for the HR and SpO2 values recorded at heart monitor installed in the PNI and to capture images of behavioral responses before and after baths. Axillary temperatures were measured with a digital thermometer and saliva samples were collected with ophthalmic sponge (Merocel) ®, refrigerated and processed by the Elisa test. The video recorded of behavioral states of 10 minutes pre-baths and 10 and 20 minutes post-baths were analyzed using the sleep-wake assessment tool validated by Brandon and Holditch-Davis. Data were recorded and stored in the proper form in Microsoft Excel spreadsheet. Statistical analysis was performed using Minitab software, version 16.1 and SPSS, version 20. In addition to the descriptive analysis of numerical variables to obtain measures of central tendency, dispersion, absolute and relative frequencies, Chi-square tests were used and Fisher Exact, the paired T-test, ANOVA and Generalized Linear Models in the data analysis. Results: The mean axillary temperatures of PNI pre-CIB and SIB were respectively 36.695 °C and 36.667 °C, p = 0.329. At 10 minutes post-CIB and SIB, the mean axillary temperatures were, respectively, 36.533 ° C to 36.535 ° C, p = 0.944. At 20 minutes post- CIB and SIB, the average of axillary temperature were 36.626°C and 36.628 ° C, p = 0.663. There was a decrease in the axillary temperature at 10 minutes post-bath, regardless of the type performed bath (p < 0.001). The hypothesis that the SIB is equivalent to the CIB related to the variation in the axillary temperature was confirmed. There was a significant reduction in the HR values at the 10th and 20 th minutes after CIB and SIB compared to pre-bath values, regardless type of the bath (p< 0.001). There was a progressive rise on SpO2 mean values on the 10th and 20 th minutes after baths with no significant differences in pre-baths values, p = 0.969. The salivary cortisol concentrations increased after bathing in both groups, p = 0.001, however there were no differences between the groups, in other words, salivary cortisol levels increased after bathing, regardless of the type of bath, p = 0.797. The percentage of time in active sleep state increased after bathing, regardless of bath type, p <0.001, that is meaning there was significant change in newborn behavior, without differences between baths, p = 0.425. Conclusion: Both the PNI who received CIB, as those receiving SIB, had a decrease in body temperature in the 10th minute post bath followed by an increased body temperature at 20 minutes post-bath. Compared to previous studies, reduction of body temperature was lower than in the sponge bath. The SIB is equivalent to the CIB therefore both are recommended for preterm infants. It should be emphasized the increased in the SIB costs due to the bed sheet consumption and the required nursing staff training in this bath technique, without extending the average time spent in the bath, as it may reduce the temperature of the bath water, consequently causing body temperature drop on the newborn

Coarse particulate organic matter (CPOM) is an essential part of the food chain in aquatic ecosystems because it represents a readily available carbon and energy source. The process by which it decomposes in rivers has been well studied and documented. However, the rate and extent of biodegradability of various CPOM components (i.e., twigs, leaves, grass, etc.) in storm drains is not well understood. The Jordan River TMDL study identified storm water generated CPOM as a likely cause of low dissolved oxygen levels in the lower Jordan River, but recent investigations have suggested that dissolved organic matter generated from this CPOM in storm drains and culverts entering into the Jordan River, rather than the CPOM itself, is the main driver of oxygen impairment. The degradability of CPOM components transported and stored in the storm drain system was studied to understand its relative impact on dissolved oxygen and nutrient status in the Jordan River. Results indicate the generation of highly degradable organic material is a function of the starting CPOM, and oxygen consumption is associated with the dissolved portion of organic material leached from CPOM in water. Leaves and grass produced the highest levels of all parameters studied. Between 93% to 95% of total oxygen demand is generated within the first 1 to 3 hours of the 24 hour test. Chemical oxygen demand and dissolved organic carbon proved to be the best indicator of biochemical oxygen demand. By using the results of the leaching study an estimate of water quality indicator levels in the Jordan River was made, and was compared to levels in samples collected from the Jordan River. The estimate proved accurate for dissolved organic carbon but not for total or volatile suspended solids. Results of this study were used to discuss possible solutions to reduce oxygen demand in the Jordan River.

Upper respiratory tract infections (URTI) are one of the most common illnesses affecting the general population and particularly athletes, often reducing the individual capacity of physical performance. Epidemiological data suggest that intensive exercise, training and competition may increase susceptibility to respiratory infections. On the other hand, some studies defend that less active subjects may reduce their risk of URTI by engaging in moderate exercise training. Nevertheless, reports are not unanimous and frequently contained various limitations. The higher incidence of infections in elite athletes has been widely attributed to immune suppression induced by exhaustive exercise, however this has not been clearly demonstrated. The present series of studies aimed to investigate the relationship between physical activity and the incidence of URTI in young healthy females with a range of physical activity levels, from sedentary to elite athletes (tennis players). Additionally, it was intended to explore the temporal association between specific characteristics of tennis training and competition, the incidence of URTI, and salivary lgA levels (μg.mr1 ; μg.min-1 ) and changes, in elite female tennis players over a 12-week period. To accomplish the objectives described, a practical method for quantifying tennis play was validated and applied. Major findings of this research include the greater incidence of URTI symptomatology in girls with low or extremely high levels of physical activity as compared to those with moderate levels. Moreover, the incidence of URTI in elite tennis players was directly correlated with the training load and competition level, on a weekly basis. In the subsequent study, one hour of intense tennis play produced a significant drop in salivary lgA secretion rate (S-lgA), and the magnitude of the immune suppression was directly associated with the amount of training undertaken during the previous day and week (P<0.05). Nevertheless, tennis training did not seem to suppress chronically salivary lgA as positive correlations were found between resting salivary lgA levels of concentration and secretion rate, and the amount of training undertaken previously. Finally, it was noted a sharper post-exercise drop in S-lgA in occasions preceding an URTI episode compared to occasions when the infection did not develop subsequently (within 7 days). However, this parameter was not a specific predictor of URTI, in this cohort of athletes.

Les mécanismes impliqués dans les adaptations du phénotype métabolique musculaire au cours de l’exercice physique restent imparfaitement connus. Nous nous sommes intéressés au concept d’hormèse mitochondriale qui se définit comme un stress métabolique activant les voies de signalisation menant à une activation mitochondriale.En première partie, nous avons validé l’utilisation d’un nouveau système de mesure des échanges gazeux chez le rat au cours de différents exercices sur tapis roulant, et démontré que pour une vitesse de course sous maximale, un exercice en descente sollicite le système cardiovasculaire de façon modérée sans altérer la fonction mitochondriale musculaire, ni augmenter la production de radicaux libres oxygénés.En deuxième partie, nous avons montré qu’un découplage mitochondrial provoqué par un traitement des rats au 2,3-dinitrophénol (DNP) pendant 3 semaines engendre des adaptations métaboliques menant à l’augmentation de la masse mitochondriale du muscle squelettique. Ces animaux ont une capacité à l’exercice diminuée, malgré une augmentation de leur VO2max.Pour finir, nous avons montré qu’un préconditionnement par l’exercice protège la mitochondrie musculaire squelettique des effets délétères de l’ischémie-reperfusion. L’exercice semble activer le métabolisme via un phénomène d’hormèse mitochondriale permettant la protection musculaire. En conclusion, cette thèse nous montre d’une part l’importance de la mitochondrie (aspect quantitatif mais surtout qualitatif) en terme de limitation à l’exercice, et d’autre part nous suggère que l'optimisation du fonctionnement mitochondrial pourrait être une bonne garantie pour pouvoir lutter efficacement contre les stress, notamment oxydatifs, auxquels l'organisme est soumis en (quasi)permanence
The mechanisms regulating the metabolic phenotype adaptations in skeletal muscle during physical exercise is still unknown.We studied the mitochondrial hormesis phenomenon that could be defined as a metabolic stress activating the signaling pathways leading to a mitochondrial stimulation (mitochondrial biogenesis).In the first part, we validated the utilization of a new system determining the gas exchange in rat during a treadmill exhaustive exercise. We showed that a submaximal downhill exercise activate moderately the cardiovascular system, without mitochondrial functional impairments and without any augmentation of the systemic ROS production. In the second part, we showed that a mitochondrial uncoupling following a dinitrophenol treatment during 3 weeks in rats induced some metabolic adaptations leading to a higher mitochondrial mass in skeletal muscle. The exercise capacity of these animals is reduced whereas the maximal oxygen consumption is higher.In the last part, we showed that a preconditioning protocol with an acute exercise protected the skeletal muscle mitochondria from the deleterious effects of ischemia-reperfusion. This exercise seems to activate the muscular metabolism via a phenomenon of mitochondrial hormesis activation, allowing an efficient muscular protection.In conclusion, this thesis shows the importance of the mitochondria in terms of qualitative and quantitative aspects and shows the participation of this organelle in the exercise limitation. Moreover, these works suggest that the optimization of the mitochondrial function could be a good guarantee in order to efficiently fight against oxidative stress at the level of the whole organism