Éditeur(s) : HAL CCSD ACSM
Résumé : International audience
PURPOSE AND METHODS: This study was designed to compare the physiological responses and performance of well trained cyclists riding with two different chainring designs, round or eccentric, during a brief and intense cycling exercise: an "all-out" 1-km laboratory test. The eccentrically designed chainring was made of two crank arms sliding into each other, with the inside arm fixed on the center of the arm of a circular chainring and the outside arm sliding along the inside and revolving around an elliptical cam. This design increases crank arm length at the downstroke and decreases it during the upstroke, thus increasing and decreasing the torque. In terms of the chainring's revolution, the crank arm length at 0 degrees and 180 degrees is similar to the arm length of circular chainrings (175 mm). However, during the downstroke (0-180 degrees ), it increases to its maximum length of 200 mm at 90 degrees and then returns to its original length of 175 mm at 180 degrees. During the upstroke, it decreases to a minimum length of 150 mm at 270 degrees and then increases to 175 mm at 360 degrees. Eleven cyclists performed an all-out 1-km laboratory test using each chainring. The study was conducted over two consecutive weeks with the order of chainring use randomized. During all trials, ventilatory data were collected every minute using an automated breath-by-breath system. Heart rate was measured using a telemetry system. RESULTS: None of the cardiorespiratory variables showed significant differences between chainring trials. Performance, however, was significantly improved using the eccentric design (64.25 +/- 1.05 vs 69.08 +/- 1.38 s, P < 0.004, with the eccentric and the round design, respectively). CONCLUSION: We concluded that the eccentric chainring significantly improved the cycling performance during an all-out 1-km test. Further testing with indoor cycling specialists performing on a velodrome would be helpful to define the maximal possibilities of such a chainring.
Medicine & Science in Sports & exercise

hal-00720551
https://hal.univ-antilles.fr/hal-00720551
https://hal.univ-antilles.fr/hal-00720551/document
https://hal.univ-antilles.fr/hal-00720551/file/Article.pdf

Éditeur(s) : HAL CCSD ACSM
Résumé : International audience
The aim of this study was to examine the effects of the cycle-run and run-cycle successions of the triathlon and duathlon, respectively, on respiratory muscle strength and endurance. Methods: Respiratory muscle strength was assessed by measuring maximal inspiratory (P1max) and expiratory {PEmax) pressures. Respiratory muscle endurance was assessed by measuring the time limit (Tlim). Twelve triathleles participated in a three-trial protocol. The first trial consisted of an incremental cycle test to assess the maximal oxygen uptake (VO2max) of triathletes. Trial 2 consisted of 20 min of cycling followed by 20 min of running (C-R), and trial 3 consisted of 20 min of running followed by 20 min of cycling (R-C). Trials 2 and 3 were performed at the same metabolic intensity (% VO2max). P1max and P1max were measured before and 10 min after C-R and R-C, and I min after the post-C-R and post-R-C Tlim measurements (P1max l'). Tlim was measured I d before and 30 min after C-R and R-C. Results: The results showed a significant decrease in P1max after C-R (126.7 ± 4.3 cmH2O, P < 0.05) and R-C (123.7 ± 4.9 cmH2O, P < 0.05) compared with the baseline values (130 ± 3.8 and 129.6 ± 4.3 cmH2O, respectively). P1max 1' showed a significantly greater decrease after R-C versus C-R(111.2 ± 5.5 cmH2O vs 121.2 ± 3.9 cmH2O,respectively, P < 0.001). Tlim after C-R (3.3 ± 0.3 min) decreased significantly compared with baseline values (4.19 ± 0.3min and 4.02 ± 0.3 min, respectively). However, the Tlim decrease after R-C was significantly greater than after C-R (P < 0.001). Conclusion: We concluded that respiratory muscle strength and endurance were less decreased after the cycle-run succession and that cycling induced a greater decrease in respiratory muscle endurance than running.
Medicine & Science in Sports & exercise

hal-00720796
https://hal.univ-antilles.fr/hal-00720796

Résumé : The caledonian blue shrimp Litopenaeus stylirostris is the second largest export commodity in New Caledonia. This industry is based on 19 production farms but also four hatcheries, two feed production units and two packing plants. The maximum production was reached in 2005 with 2400 tons. Supply of juveniles by hatchery is the bottle neck of the production chain because this species is not present in the natural environment. Recent problems of larval survival led some scientists to work on eco-physiology to propose adaptations of larval rearing protocol. Salinity of the rearing environment is taken as an example to study the influence of abiotic parameters on the animal physiology according to its development stage. The influence of salinity on survival and growth was evaluated at different development stages in Litopenaeus stylirostris. The study showed that ocean salinity (33-35 ppt) should be maintained during the larval stage, but after the post-larval metamorphosis, better growth could be achieved by lowering the salinity gradually to 27 ppt. This measure is now applied routinely in the Saint Vincent's hatchery and is the result of research in eco-physiology showing that the blue shrimp iso-osmotic point is around 27 ppt.
La crevette bleue calédonienne Litopenaeus stylirostris est au deuxième rang des produits exportés en Nouvelle-Calédonie. L’industrie crevetticole calédonienne est basée sur 19 fermes de production mais également 4 écloseries, 2 provendiers et 2 usines de conditionnement. La production maximale a été atteinte en 2005 avec 2400 tonnes. La fourniture de juvéniles par les écloseries est le point crucial de la chaîne de production car cette espèce n’est pas présente dans le milieu naturel. Les récents problèmes de survie larvaire ont orienté une partie de la recherche vers l’éco-physiologie en vue de proposer des adaptations du protocole d’élevage. La salinité du milieu d’élevage est prise comme exemple pour étudier l’influence d’un paramètre abiotique sur la physiologie de l’animal en fonction de son stade de développement. L’influence de la salinité sur la survie et la croissance a été évaluée aux différents stades de développement chez Litopenaeus stylirostris. L'étude a permis de montrer que la salinité océanique (33-35 ppt) devait être maintenue durant la phase larvaire mais qu'après la métamorphose en post-larve, une meilleure croissance pouvait être obtenue en abaissant la salinité progressivement à 27 ppt. Cette mesure est maintenant appliquée en routine en élevage larvaire à l'écloserie de Saint-Vincent et découle des recherches menées en éco-physiologie qui situe le point iso-osmotique de la crevette bleue autour de 27 ppt.

Droits : 2011 Ifremer
http://archimer.ifremer.fr/doc/00115/22658/20603.pdf
http://archimer.ifremer.fr/doc/00115/22658/

Résumé : Rapport d'activité 1995 du GAP (Laboratoire Génétique, Aquaculture, Pathologie) de La Tremblade.

Droits : 1995 Ifremer
http://archimer.ifremer.fr/doc/00071/18253/15816.pdf
http://archimer.ifremer.fr/doc/00071/18253/

Éditeur(s) : HAL CCSD ACSM
Résumé : International audience
PURPOSE AND METHODS: This study was designed to determine whether the physiological responses elicited during the run part of repeated bouts of cycle-run exercise are similar to those required during the run segment of a cycle-run succession. Thirteen male triathletes underwent four successive laboratory trials: 1) an incremental treadmill test, 2) an incremental cycle test, 3) 30 min of cycling followed by 20 min of running (C-R), and 4) five repeated bouts of 6 min of cycling and 4 min of running (X-CR). During the C-R and X-CR trials, venous blood samples were obtained to measure lactate, epinephrine and norepinephrine concentrations. During all trials, ventilatory data were collected every min using an automated breath-by-breath system. RESULTS: The results showed that 1) the cardiorespiratory responses observed during running were similar in the X-CR and C-R trials, 2) the lactate concentration was similar in both trials, 3) the epinephrine concentration was greater (277.9 +/- 11.9 vs 169.8 +/- 86.7 pg x mL(-1), P < 0.025) in X-CR than in C-R, and 4) the norepinephrine concentration was similar in both trials, except at the first cycle-run succession (T1) of X-CR. CONCLUSION: We concluded that 1) multi-block training is a good method to stimulate the specific adaptations required for the cycle-run succession, and particularly for the cycle-run transition, and 2) multi-block training seems to induce a greater catecholaminergic response, which may be due to a combination of an inherent effect of this type of training and the triathletes' relative lack of experience with it. In any case, the efficacy of the multi-block model needs to be more thoroughly evaluated over the course of a longer-term training program.
Medicine & Science in Sports & exercise

hal-00720475
https://hal.univ-antilles.fr/hal-00720475
https://hal.univ-antilles.fr/hal-00720475/document
https://hal.univ-antilles.fr/hal-00720475/file/Article_2_.pdf

Éditeur(s) : HAL CCSD
Résumé : International audience
This study investigated the possibility of there being differences in respiratory muscle strength and endurance in elite and competition triathletes who have similar maximal oxygen uptakes (V_O2max) and ventilatory thresholds (Thvent). Five internationally-ranked elite, [mean (SD) age 23.8 (1.4) years] and six nationallyand regionally-ranked competition [age 21.1 (1.1) years] male triathletes performed two successive trials: first an incremental cycle test to assess V_O2max and Thvent and second 20 min of cycling followed by 20 min of running (C-R) at intensities higher than 85% V_O2max. Cardioventilatory data were collected every minute during the two trials, using an automated breath-by-breath system. Maximal expiratory and inspiratory (PImax) strength were assessed before and 10 min after C-R from the functional residual capacity. Respiratory muscle endurance was assessed 1 day before and 30 min after C-R by measuring the time limit (tlim). The results showed firstly that during C-R, the competition triathletes had significantly (P<0.05) higher minute ventilation [mean (SEM) 107.4 (3.1) compared to 99.8 (3.7) lÆmin-1], breathing frequency [44.4 (2.0) compared to 40.2 (3.4) Æmin-1] and heart rate [166 (3) compared to 159 (4) beatsÆmin-1] and secondly that after C-R, they had significantly lower PImax [127.1 (4.2) compared to 130.7 (3.0) cmH2O] and tlim [2:35 (0:29) compared to 4:12 (0:20) min] than the elite triathletes. We conclude that, despite similar V_O2max and Thvent, the competition triathletes showed less extensive adaptive mechanisms, including those in the respiratory muscles, than did the elite triathletes. This led to higher ventilation, which appeared to be the cause of the faster development of fatigue in the inspiratory muscles in this group.
EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY

hal-00720562
https://hal.univ-antilles.fr/hal-00720562
https://hal.univ-antilles.fr/hal-00720562/document
https://hal.univ-antilles.fr/hal-00720562/file/BoussanaEJAP02_2_.pdf

Résumé : Ce rapport synthétise les communications faites lors des "journées conchylicoles" sur les travaux scientifiques de l'Ifremer en soutien aux activités conchylicoles

Droits : 2003 Ifremer
http://archimer.ifremer.fr/doc/00200/31115/29526.pdf
http://archimer.ifremer.fr/doc/00200/31115/

Éditeur(s) : HAL CCSD
Résumé : International audience
To determine whether exercise modality affects arterial hypoxemia (EIAH) during training-intensity exercise, 13 triathletes performed 20 min of cycling (C) followed by 20 min of running (R): C-R, and two weeks later, 20 min of R followed by 20 min of C:R-C. Each trial was performed at an intensity slightly above the ventilatory threshold and close to the daily training intensity (75 % of VO2max). Ventilatory data were collected continuously using an automated breath-by-breath system. Partial pressure of oxygen in arterial blood (PaO2) was measured after each C and R segment and arterial oxyhemoglobin saturation (SpO2) was monitored continuously via pulse oximetry. The metabolic rate was similar across modalities and trials, i.e., C-R (53.8 +/- 3.8 vs. 51.1 +/- 5.3 ml.min(-1).kg(-1)) and R-C (52.2 +/- 4.5 vs. 53.2 +/- 4.6 ml.min(-1).kg (-1)). EIAH showed significantly greater severity for R compared to C irrespective of the order (p < 0.05 for both trials). R values of PaO2 (and SpO2) for C-R and R-C were 88.7 +/- 6.0 mm Hg (93.0 +/- 0.6 % SpO2) and 86.6 +/- 7.3 mm Hg (93.5 +/- 0.6 % SpO2) and C values were 93.7 +/- 8.4 mm Hg (95.4 +/- 0.4 % SpO2) and 91.4 +/- 5.4 mm Hg (94.8 +/- 0.3 % SpO2). R ventilatory data described a significantly different breathing pattern than C, with higher respiratory rate (35.9 b.min(-1) vs. 51.1 b.min(-1) for C-R, p < 0.01; and 50.0 b.min(-1) vs. 41.5 b.min(-1) for R-C, p < 0.01) and lower tidal volume (2636 ml vs. 2282 ml for C-R, p < 0.02 and 2272 ml vs. 2472 ml for R-C, p < 0.05). We concluded that EIAH was greater during running than cycling for a similar metabolic rate corresponding to training intensity and that EIAH could thus be considered dependent on exercise modality.
Internation Journal of Sports Medicine

hal-00720806
https://hal.univ-antilles.fr/hal-00720806
https://hal.univ-antilles.fr/hal-00720806/document
https://hal.univ-antilles.fr/hal-00720806/file/sm290.pdf

Éditeur(s) : HAL CCSD Human Kinetics
Résumé : International audience
In order to study the acclimatization process over 14 days of exposure to tropical climate, 9 triathletes performed 4 outdoor indirect continuous multistage tests in both thermoneutral and tropical conditions. The thermoneutral test (TN, 14 C, 45% rh) was performed before traveling to the tropical area (Martinique, FWI). The tropical tests were performed 2, 8, and 14 days after arrival (32.9 C, 78% rh). During each trial, we measured tympanic temperature, sweat rate, body mass loss, heart rate (HR), and performance. The results showed that 1) the mean tympanic temperature was greater in T2 (P < .001), T8 (P < .01) and T14 (P < .01) than in TN and significantly lower in T14 than in T2 (P < .05); 2) the mean sweat rate was significantly greater (P < .001) in T2, T8 and T14 than in TN and significantly greater (P < .05) in T8 and T14 than in T2; 3) the body mass loss after trials was significantly greater (P < .001) in T2, T8 and T14 than in TN and significantly greater (P < .05) in T8 and T14 than in T2; 4) the mean HR and HR at rest were significantly higher (P < .005) in T2 than in TN, T8, T14 and the mean HR was significantly lower (P < .05) in T14 than in the other trials; and 5) the performance time was significantly lower in T2 (P < 0.02), T8 (P < 0.03) and T14 (P < 0.05) than in TN. We concluded that 14 days of exposure.
ISSN: 1066-7814

hal-00720075
https://hal.univ-antilles.fr/hal-00720075
https://hal.univ-antilles.fr/hal-00720075/document
https://hal.univ-antilles.fr/hal-00720075/file/02.Voltaire_551_.pdf

Éditeur(s) : HAL CCSD
Résumé : Inorganic arsenic is an environmental human carcinogen, but is also studied these days because of its potential effectiveness in curing chronic inflammatory disease. Indeed, this metalloid possesses immunosuppressive properties which can dysregulate physiological mechanisms involved in immune defense, or reduce inflammation associated with those inflammatory diseases. Inorganic arsenic is known mainly to alter functions of T cells and macrophages. However, it is unknown whether arsenic targets dendritic cells (DCs). Yet, this antigen presenting cells plays a major role in the immunosurveillance, and is involved in the physiopathology of chronic inflammatory diseases. So, the aim of my thesis work was to study the effects of inorganic arsenic on in vitro differenciation and maturation of dendritic cells from human monocytes. Our results mainly shows that concentrations corresponding to those measured in environmentally exposed people, inhibits DCs secretion of proinflammatory cytokines, which plays a major role in activation and polarization of T cells. Particularly, arsenic strongly impairs expression and secretion of interleukine 12 (IL-12) by an underlying molecular mechanism involving Nrf2. Finally, this work shows that inorganic arsenic has immunosuppressive properties on the physiology in vitro of human dendritic cells. Immunotoxicity may then contribute to the metalloid toxicity in environmentally exposed people. This element could be taken into account when determining arsenic effects in curing some chronic inflammatory diseases.
L’arsenic inorganique est un contaminant environnemental, cancérogène pour l’homme, mais également un métalloïde étudié, aujourd’hui, dans le traitement de maladies inflammatoires chroniques. Il possède des propriétés immunosuppressives pouvant déréguler les mécanismes physiologiques de défense ou bloquer l’exacerbation de réponses inflammatoires chroniques. L’arsenic inorganique altère principalement les fonctions des lymphocytes T et des macrophages. En revanche, l’impact du métalloïde sur la physiologie des cellules dendritiques (DCs) est peu connu. Pourtant, ces cellules présentatrices d’antigène jouent un rôle fondamental dans les processus d’immunosurveillance et sont très impliquées dans la physiopathologie des maladies inflammatoires chroniques. Dans ce contexte, les objectifs de mon travail de thèse étaient d’étudier les effets de l’arsenic inorganique sur la différenciation et la maturation in vitro de DCs générées à partir de monocytes humains. Nos résultats démontrent principalement que des concentrations de métalloïde, compatibles avec les taux plasmatiques d’arsenic mesurés chez les individus exposés, répriment la capacité des DCs à sécréter différentes cytokines pro-inflammatoires jouant un rôle essentiel dans l’activation et la polarisation des lymphocytes T. En particulier, l’arsenic inhibe l’expression et la sécrétion de l’interleukine-12 par un mécanisme moléculaire impliquant le facteur de transcription Nrf2. Au total, ces travaux de thèse démontrent que l’arsenic inorganique possède des propriétés immunosuppressives sur la physiologie in vitro des DCs humaines. Cette immunotoxicité pourrait contribuer à la toxicité du métalloïde chez l’homme exposé par voie environnementale, et être prise en compte pour déterminer les effets de l’arsenic dans le traitement de certaines maladies inflammatoires chroniques
https://tel.archives-ouvertes.fr/tel-01135887

NNT : 2013REN1B013
tel-01135887
https://tel.archives-ouvertes.fr/tel-01135887
https://tel.archives-ouvertes.fr/tel-01135887/document
https://tel.archives-ouvertes.fr/tel-01135887/file/pdf2star-1392896105-Th--se-M--linda-Macoch2.pdf

Éditeur(s) : HAL CCSD
Résumé : International audience
Up-to-date estimates of the health outcomes of preterm children are needed for assessing perinatal care, informing parents, making decisions about care, and providing evidence for clinical guidelines. To determine survival and neonatal morbidity of infants born from 22 through 34 completed weeks' gestation in France in 2011 and compare these outcomes with a comparable cohort in 1997. The EPIPAGE-2 study is a national, prospective, population-based cohort study conducted in all maternity and neonatal units in France in 2011. A total of 2205 births (stillbirths and live births) and terminations of pregnancy at 22 through 26 weeks' gestation, 3257 at 27 through 31 weeks, and 1234 at 32 through 34 weeks were studied. Cohort data were collected from January 1 through December 31, 1997, and from March 28 through December 31, 2011. Analyses for 1997 were run for the entire year and then separately for April to December; the rates for survival and morbidities did not differ. Data are therefore presented for the whole year in 1997 and the 8-month and 6-month periods in 2011. Survival to discharge and survival without any of the following adverse outcomes: grade III or IV intraventricular hemorrhage, cystic periventricular leukomalacia, severe bronchopulmonary dysplasia, retinopathy of prematurity (stage 3 or higher), or necrotizing enterocolitis (stages 2-3). A total of 0.7% of infants born before 24 weeks' gestation survived to discharge: 31.2% of those born at 24 weeks, 59.1% at 25 weeks, and 75.3% at 26 weeks. Survival rates were 93.6% at 27 through 31 weeks and 98.9% at 32 through 34 weeks. Infants discharged home without severe neonatal morbidity represented 0% at 23 weeks, 11.6% at 24 weeks, 30.0% at 25 weeks, 47.5% at 26 weeks, 81.3% at 27 through 31 weeks, and 96.8% at 32 through 34 weeks. Compared with 1997, the proportion of infants surviving without severe morbidity in 2011 increased by 14.4% (P < .001) at 25 through 29 weeks and 6% (P < .001) at 30 through 31 weeks but did not change appreciably for those born at less than 25 weeks. The rates of antenatal corticosteroid use, induced preterm deliveries, cesarean deliveries, and surfactant use increased significantly in all gestational-age groups, except at 22 through 23 weeks. The substantial improvement in survival in France for newborns born at 25 through 31 weeks' gestation was accompanied by an important reduction in severe morbidity, but survival remained rare before 25 weeks. Although improvement in survival at extremely low gestational age may be possible, its effect on long-term outcomes requires further studies. The long-term results of the EPIPAGE-2 study will be informative in this regard.
ISSN: 2168-6211

hal-01258705
http://hal.univ-brest.fr/hal-01258705
PUBMED : 25621457
DOI : 10.1001/jamapediatrics.2014.3351

Éditeur(s) : HAL CCSD
Résumé : International audience
The aim of the present study was to determine the effects of 40 km of cycling on the biomechanical and cardiorespiratory responses measured during the running segment of a classic triathlon, with particular emphasis on the time course of these responses. Seven male triathletes underwent four successive laboratory trials: (1) 40 km of cycling followed by a 10-km triathlon run (TR), (2) a 10-km control run (CR) at the same speed as TR, (3) an incremental treadmill test, and (4) an incremental cycle test. The following ventilatory data were collected every minute using an automated breath-by-breath system: pulmonary ventilation VE, l x min[-1]), oxygen uptake (VO2, ml x min(-1) x kg[-1]), carbon dioxide output (ml x min[-1]), respiratory equivalents for oxygen (VE/VO2) and carbon dioxide (VE/VCO2), respiratory exchange ratio (R) respiratory frequency (f, breaths x min[-1]), and tidal volume (ml). Heart rate (HR, beats x min[-1]) was monitored using a telemetric system. Biomechanical variables included stride length (SL) and stride frequency (SF) recorded on a video tape. The results showed that the following variables were significantly higher (analysis of variance, P < 0.05) for TR than for CR: VO2 [51.7 (3.4) vs 48.3 (3.9) ml x kg(-1) x min(-1), respectively], VE [100.4 (1.4) l x min(-1) vs 84.4 (7.0) l x min(-1)], VE/VO2 [24.2 (2.6) vs 21.5 (2.7)] VE/VCO2 [25.2 (2.6) vs 22.4 (2.6)], f[55.8 (11.6) vs 49.0 (12.4) breaths x min(-1)] and HR [175 (7) vs 168 (9) beats x min(-1)]. Moreover, the time needed to reach steady-state was shorter for HR and VO2 (1 min and 2 min, respectively) and longer for VE (7 min). In contrast, the biomechanical parameters, i.e. SL and SF, remained unchanged throughout TR versus CR. We conclude that the first minutes of the run segment after cycling in an experimental triathlon were specific in terms of VO2 and cardiorespiratory variables, and nonspecific in terms of biomechanical variables.
EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY

hal-00720703
https://hal.univ-antilles.fr/hal-00720703
https://hal.univ-antilles.fr/hal-00720703/document
https://hal.univ-antilles.fr/hal-00720703/file/EJAP.pdf

Éditeur(s) : HAL CCSD National Institute of Environmental Health Sciences (NIEHS) National Institute of Environmental Health Sciences
Résumé : International audience
Long-term exposure to persistent pollutants with hormonal properties (endocrine-disrupting chemicals, EDCs) may contribute to the risk of prostate cancer (PCa). However, epidemiological evidence remains limited. We investigated the relationship between PCa and plasma concentrations of universally widespread pollutants, in particular p,p'-dichlorodiphenyl dichloroethene (DDE) and the non-dioxin like polychlorinated biphenyl congener 153 (PCB153). We evaluated before treatment 576 men with newly diagnosed PCa and 655 controls in Guadeloupe (French West Indies). Exposure was analyzed according to case-control status. Associations were assessed by unconditional logistic regression analysis, controlling for confounding factors. Missing data were handled by multiple imputation. We estimated a significant positive association between DDE and PCa (adjusted odds ratio [OR] 1.53; 95% CI 1.02, 2.30 for the highest versus lowest quintile of exposure; PTrend = 0.01). PCB153 was inversely associated with PCa (OR 0.30; 95% CI 0.19, 0.47 for the highest versus lowest quintile of exposure values; PTrend < 0.001). Also, PCB153 was more strongly associated to low-grade than high grade PCa. Associations of PCa with DDE and PCB153 were in opposite directions. This may reflect differences in the mechanisms of action of these EDCs, and although our findings need to be replicated in other populations, they are consistent with complex effects of EDCs on human health.
ISSN: 0091-6765

hal-01118553
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01118553
DOI : 10.1289/ehp.1408407
PUBMED : 25493337

Éditeur(s) : HAL CCSD
Résumé : International audience
Previous studies have reported respiratory, cardiac and muscle changes at rest in triathletes 24 h after completion of the event. To examine the effects of these changes on metabolic and cardioventilatory variables during exercise, eight male triathletes of mean age 21.1 (SD 2.5) years (range 17-26 years) performed an incremental cycle exercise test (IET) before (pre) and the day after (post) an official classic triathlon (1.5-km swimming, 40-km cycling and 10-km running). The IET was performed using an electromagnetic cycle ergometer. Ventilatory data were collected every minute using a breath-by-breath automated system and included minute ventilation (V(E)), oxygen uptake (VO2), carbon dioxide production (VCO2), respiratory exchange ratio, ventilatory equivalent for oxygen (V(E)/VO2) and for carbon dioxide (V(E)/VCO2), breathing frequency and tidal volume. Heart rate (HR) was monitored using an electrocardiogram. The oxygen pulse was calculated as VO2/HR. Arterialized blood was collected every 2 min throughout IET and the recovery period, and lactate concentration was measured using an enzymatic method. Maximal oxygen uptake (VO2max) was determined using conventional criteria. Ventilatory threshold (VT) was determined using the V-slope method formulated earlier. Cardioventilatory variables were studied during the test, at the point when the subject felt exhausted and during recovery. Results indicated no significant differences (P > 0.05) in VO2max [62.6 (SD 5.9) vs 64.6 (SD 4.8) ml x kg(-1) x min(-1)], VT [2368 (SD 258) vs 2477 (SD 352) ml x min(-1)] and time courses of VO2 between the pre- versus post-triathlon sessions. In contrast, the time courses of HR and blood lactate concentration reached significantly higher values (P < 0.05) in the pre-triathlon session. We concluded that these triathletes when tested 24 h after a classic triathlon displayed their pre-event aerobic exercise capacity, bud did not recover pretriathlon time courses in HR or blood lactate concentration.
EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY

hal-00720432
https://hal.univ-antilles.fr/hal-00720432
https://hal.univ-antilles.fr/hal-00720432/document
https://hal.univ-antilles.fr/hal-00720432/file/Article_2.pdf

Éditeur(s) : HAL CCSD
Résumé : Diffusion du document : INRA Antilles-Guyane, UMR ECOFOG, 97387 Kourou, Guyane (France) Diplôme : Diplôme d'Ingénieur des Techniques Forestières
il s'agit d'un type de produit dont les métadonnées ne correspondent pas aux métadonnées attendues dans les autres types de produit : DISSERTATION
Le stage est principalement centré sur l'étude des traits de croissance, de physiologie et de morphologie foliaire sur des populations de plantules d'Eperua falcata (en forêt et en serre ) et de Sextonia rubra (en serre) afin d' étudier la diversité et la différenciation entre pieds mères, d'une part, et l'héritabilité d'autre part. L'héritabilité est une mesure du degré de transmission d'un caractère ; elle représente (en terme statistique) le rapport de la variance phénotypique d'origine génétique. A travers une analyse de variance (ANOVA) on a pu estimer les différentes composantes de la variance (génétique et résiduelle) des traits pour les deux espèces. Les différences génétiques trouvées entre pieds mères jouent un rôle important dans la variabilité des traits. Pour E. falcata, les héritabilités obtenues nous donnent, dans certains traits, des valeurs fortes et similaires en serre et en forêt (ex. l'épaisseur) et dans d'autres, des résultats assez variables à cause de l'interaction génotype- environnement. Par contre pour le S. rubra, les valeurs d'héritabilité sont très homogènes dans la majorité des traits étudiés en serre. Cela montre que, du point de vue écologique aussi bien que du point de vue de gestion, il est indispensable de prendre en compte la variabilité individuelle et héritable, l'adaptabilité et l'adaptation au milieu, comme paramètres de tout modèle des communautés végétales de la Forêt Tropicale Humide. L'ensemble des résultats nous donne une forte motivation pour poursuivre les analyses, dans le temps ou dans la reformulation de la conception des dispositifs avec des transplantations réciproques en pleine forêt.
https://hal.archives-ouvertes.fr/hal-01189280

hal-01189280
https://hal.archives-ouvertes.fr/hal-01189280
PRODINRA : 22857

Éditeur(s) : HAL CCSD Thieme Publishing
Résumé : International audience
To determine the effect of triathlete performance level on the cardiorespiratory responses elicited by the cycle-run succession, eight regionally and nationally-ranked (Competitive) and five internationally-ranked (Elite) male triathletes underwent four successive laboratory trials: 1) an incremental treadmill test, 2) an incremental cycle test, 3) 30 min of cycling followed by 20 min of running (C-R), and 4) a 20-min control run (R) at the same speed as the run in C-R. Before and 10 min after the third and fourth trials the triathletes underwent lung function testing: spirometry and diffusing capacity testing for carbon monoxide (DL(CO)). During the C-R trial blood samples were drawn to measure venous lactate concentration. During all trials ventilatory data were collected every minute using an automated breath-by-breath system. The results showed that 1) the oxygen uptake (VO2) of post-cycling running versus running alone was similar for both groups; 2) the ventilatory responses (VE, VE/VO2, VE/VC02 and f) of C-R running versus R were significantly higher (P < 0.005) for the Competitive group; and 3) a significant decrease (P< 0.05) in DL(CO) was also noted after the C-R trial in the Competitive group but not in the Elite group. We concluded that 1) the ventilatory responses during a run subsequent to cycling may be related to the triathlete performance level, and 2) the C-R trial induced specific alterations in pulmonary function that may be associated with respiratory muscle alteration and exercise-induced hypoxemia in the Competitive triathletes.
ISSN: 0172-4622

hal-00720719
https://hal.univ-antilles.fr/hal-00720719

Résumé : This catalogue deals mainly with common phytoplanktonic species found in the Channel. It is part of a bibliographical survey on pelagos and benthos. The main idea was to gather the largest possible amount of data on the eco-physiology of each species. To do so, studies were conducted in the main marine region where the species had been found and analysed. We focused on several reference ecological studies conducted in the coastal Channel, on the E.D.F. sites, by the C.N.E.X.O., the I.S.T.P.M. and some university laboratories. A great attention was also paid to the studies on seasonal cycles carried out in laboratories in Plymouth, Helgoland and in the Irish zones. (unverified OCR)
Ce catalogue se rapporte essentiellement aux espèces phytoplanctoniques les plus courantes et abondantes en Manche; il s'insère dans une synthèse bibliographique générale concernant le pélagos et le benthos. Nous nous sommes proposés de rassembler le plus grand nombre de données sur l'éco-physiologie de chaque espèce. Pour ce faire, les recherches se sont déroulées dans les principales régions maritimes où l'espèce avait été rencontrée et étudiée. Plus particulièrement, notre attention s'est portée sur les études écologiques de référence effectuées en Manche Littorale sur les sites E.D.F. par le C.N.E.X.O., l'I.S.T.P.M, et les laboratoires universitaires; d'importance aussi, furent les études de cycles saisonniers effectuées au laboratoire de Plymouth, d'Helgoland, et dans les zones irlandaises. OCR NON CONTROLE

Droits : info:eu-repo/semantics/openAccess
http://archimer.ifremer.fr/doc/1984/rapport-3701.pdf
http://archimer.ifremer.fr/doc/00000/3701/

Résumé : L’équipe de l’IFREMER du centre de Polynésie et celle de la Cellule Innovation et Valorisation de la Direction des Ressources Marines de Polynésie Française mènent des travaux afin de maîtriser la zootechnie de l’élevage du Platax (Platax orbicularis) en lagon. Des connaissances sur la physiologie de la reproduction s’est faite sur ces animaux, mais aucune information n’est disponible quant à l’évolution de la productivité de ces animaux en fonction de leur croissance (pas de données d’âge). Le pôle national de sclérochronologie de l’Ifremer de Boulogne-sur-Mer a été sollicité pour réaliser une étude de faisabilité de l’estimation de l’âge de cette espèce. Pour cela, dans un premier temps des techniques de préparation ont été utilisées sur des otolithes de poissons ayant un âge connu (élevés en aquaculture). Une fois, cette validation faite, des tests ont été entrepris sur des individus sauvages (d’âge inconnu) en fonction des structures de croissance observées sur des otolithes de poissons d’âge connu.

Droits : 2013 Ifremer
http://archimer.ifremer.fr/doc/00180/29158/27563.pdf
http://archimer.ifremer.fr/doc/00180/29158/

Éditeur(s) : HAL CCSD American College of Sports Medicine (ACSM)
Résumé : International audience
PURPOSE AND METHODS: To determine the effects of cycling on a subsequent triathlon run, nine male triathletes underwent four successive laboratory trials: 1) an incremental treadmill test, 2) an incremental cycle test, 3) 30 min of cycling followed by 5 km of running (C-R), and 4) 30 min of running followed by 5 km of running (R-R). Before and 10 min after the third and fourth trials, the triathletes underwent pulmonary function testing including spirometry and diffusing capacity testing for carbon monoxide (DL(CO)). During the C-R and R-R trials, arterialized blood samples were obtained to measure arterial oxygen pressure (PaO2). During all trials, ventilatory data were collected every minute using an automated breath-by-breath system. RESULTS: The results showed that 1) the oxygen uptake (VO2) observed during subsequent running was similar for the C-R and R-R trials; 2) the ventilatory response (VE) during the first 8 min of subsequent running was significantly greater in the C-R than in R-R trial (P < 0.05); 3) only the C-R trial induced a significant increase (P < 0.05) in residual volume (RV), functional residual capacity (FRC), and the ratio of residual volume to total lung capacity (RV/TLC); and 4) although a significant decrease (P < 0.05) in DL(CO) was noted after C-R, no difference between the two exercise trials was found for the maximal drop in PaO2. CONCLUSIONS: We concluded that 1) the C-R trial induced specific alterations in pulmonary function that may be associated with respiratory muscle fatigue and/or exercise-induced hypoxemia, and 2) the greater VE observed during the first minute of running after cycling was due to the specificity of cycling. This reinforces the necessity for triathletes to practice multi-trial training to stimulate the physiological responses experienced during the swim-cycle and the cycle-run transitions.
ISSN: 0195-9131

hal-00720412
https://hal.univ-antilles.fr/hal-00720412
https://hal.univ-antilles.fr/hal-00720412/document
https://hal.univ-antilles.fr/hal-00720412/file/Article.pdf

Éditeur(s) : HAL CCSD
Résumé : Macrophages (MΦ), well-known to play a key role in immune response, also respond to environmental toxic chemicals such as diesel exhaust particles (DEP), an air pollutant recently classified as carcinogenic to humans. MΦ are heterogeneous and plastic cells which activate according to their microenvironment into either an M1 subtype (so called classically activated or pro-inflammatory) under IFNγ and LPS stimulation or an M2 subtype (so called alternatively activated or anti-inflammatory) under IL-4 and/or IL-13 stimulation. However, potential effects of DEPs on M1/M2 MΦ polarization remain poorly documented. First, we characterized the expression marker of in vitro M-CSF-differentiated MΦ from human monocytes and activated into the M1 or M2 subtypes. Our main results show that M-CSF-generated MΦ considered as anti-inflammatory are actually able to switch to an M1 phenotype after IFNγ/LPS stimulation. Furthermore, the markers identified in this study were used to assess the impact of organic extracts of DEP (DEPe) on MΦ polarization and more generally on their physiology. DEPe alter some M1 and M2 markers expressed by polarized MΦ, without causing the overall inhibition of the M1 and M2 polarization process or the switch to a different phenotype. This phenotype alteration is associated with a decrease in the LPS-dependent inflammatory response in M1 MΦ and the chemotactic capacities in M2 MΦ. DEPe decrease the secretion of some cytokines and chemokines such as IL-6, IL-12p40 and CCL18 via AhR and/or Nrf2 activation. At the same time, we show that M1 and M2 MΦ in response to DEPe are able to secrete a sufficient level of a pro-fibrotic growth factor, the platelet derived growth factor B (PDGF-B) via AhR activation, leading to stimulation of lung fibroblast proliferation. Finally, these works show that DEPe have immunotoxic properties with regards to the physiology of human in vitro polarized MΦ. This immunotoxicity may then contribute to the deleterious effects of these urban environmental contaminants on human health.
Les macrophages (MΦ), des cellules clefs de la réponse immunitaire peuvent répondre à des contaminants environnementaux comme les particules diesel (DEP), des polluants atmosphériques récemment classés cancérigènes pour l'Homme. Les MΦ sont des cellules hétérogènes et plastiques qui s'activent en fonction de leur microenvironnement soit en MΦ M1 (dits classiquement activés ou pro-inflammatoires) sous l'effet de l'INFγ et du LPS soit en MΦ M2 (dits alternativement activés ou réparateurs) sous l'effet de l'IL-4 et/ou de l'IL-13. Les effets des DEP sur la polarisation M1/M2 des MΦ restent peu documentés. Nous avons dans un premier temps caractérisé l'expression des marqueurs des MΦ différenciés in vitro en présence de M-CSF à partir de monocytes humains et polarisés en sous-type M1 ou M2. Nos principaux résultats montrent que les MΦ différenciés au M-CSF considérés comme des MΦ anti-inflammatoires, sont en réalité capables de s'activer vers un phénotype M1 après une stimulation au LPS/IFNγ. De plus, les marqueurs mis en évidence au cours de ce travail ont permis d'évaluer l'impact d'extraits organiques de DEP (DEPe) sur la polarisation des MΦ et plus généralement sur leur physiologie. Les DEPe altèrent l'expression de certains marqueurs M1 et M2 des MΦ, sans toutefois provoquer d'inhibition globale des processus de polarisation M1 et M2 ou de transition d'un phénotype vers un autre. Cette altération du phénotype est associée à une diminution de la réponse inflammatoire LPS-dépendante dans les MΦ M1 et des capacités chimiotactiques des MΦ M2. Les DEPe diminuent la sécrétion de certaines cytokines et chimiokines comme l'IL-6, l'IL-12p40 et le CCL18 via l'activation d'AhR et/ou de Nrf2. Parallèlement, nous montrons que les MΦ M1 et M2 exposés aux DEPe sécrètent le platelet deried growth factor B (PDGF-B), un facteur de croissance profibrosant, via l'activation d'AhR en quantité suffisante pour stimuler la prolifération de fibroblastes pulmonaires. Au total, ces travaux démontrent que les DEP possèdent des propriétés immunotoxiques vis-à-vis de la physiologie des macrophages humains polarisés in vitro. Cette immunotoxicité pourrait participer aux effets délétères de ces contaminants environnementaux urbains sur la santé humaine.
https://tel.archives-ouvertes.fr/tel-01188679

NNT : 2015REN1S011
tel-01188679
https://tel.archives-ouvertes.fr/tel-01188679
https://tel.archives-ouvertes.fr/tel-01188679/document
https://tel.archives-ouvertes.fr/tel-01188679/file/JAGUIN_Marie.pdf