Odile Michaux

Effects of a high fat diet on bone of growing rats. Correlations between visceral fat, adiponectin and bone mass density

In this study, we investigated some bone parameters (bone mineral content, bone mineral density, skeleton area) in growing rats fed with a high fat diet. Correlations between bone and body composition parameters are reported. Two groups of Wistar male rats (35 days old, body mass 80 ± 6 g) were used. Water and food were given ad libitum during 10 weeks. Sixteen rats (L) were given a lipid enriched diet and were compared to 16 rats (S) fed with a standard diet. Body composition and bone parameters were assessed using DXA. Results indicated that L rats had lower body mass, lean body mass; fat mass was not different between the two groups. Bone mineral content, bone mineral density, skeleton area of L rats were lower compared with S rats. Significant correlations were noted between body composition, adiponectin and bone parameters. High fat diet intake during the growing period has deleterious effects on bone parameters in rats. This study confirms in growing rats that a high fat diet is pathogenic, including bone metabolism.

Psychoendocrine and physical performance responses in male Tunisian rugby players during an international competitive season.

The aim was to investigate a follow-up study based on hormonal, physical, and psychological parameters among rugby players who trained during a whole season interspersed with competitions on an international level. Fitness or reciprocally tiredness as well as competitive anxiety were evaluated, respectively, using the French Society for Sports Medicine (SFMS) and the sport competition anxiety test (SCAT) questionnaires. In this study, SFMS and SCAT scores increased respectively over the competitive season. The SFMS score revealed a state of relative tiredness at the end of the season, highlighted by a slight decrement in physical performances. The SCAT score changes are related to the competition context and therefore increased accordingly to the importance of the competition stake. We analyzed the corticotrope and the gonadotrope axis before (T(1)), and at the end of the national and international rugby season (T(2)). Training did not affect the resting salivary cortisol (Csal) levels, but induced a decrease in resting testosterone (Tsal) values, resulting in a dropped T/C ratio. Competition, in both periods (T(1)-T(2)), provoked a significant increase in Csal levels, but the Tsal responses depended on the match stake. Their concentrations increased when the competition generated an important stress and decreased when the psychological conditions remained relatively stable. SFMS is preferentially correlated with resting Csal levels and T/C values measured at 08:00 hr but not with Tsal. SCAT is highly correlated with competitive Csal and Tsal concentrations measured before and after the matches.

Effect of a moderate exercise on the regulatory hormones of food intake in rats

Strategies used to counteract overweight include generally endurance exercise. Force-resistance exercise has not been tested yet with this objective. The aim of this study was to investigate the response of the main regulatory hormones of food intake (insulin, adiponectin, leptin, ghrelin) and corticosterone, to a short force resistance exercise. Two groups of 16 rats, 65 days old, weighing 330g, were constituted. A standard diet (containing glucid: 72.2, lipid: 7.7, protid: 20% calories) was given ad libitum. One group served as control, the second group was submitted to exercise training during 5 weeks. Training reduced the rats body weight by 6.4% and the total food intake during the 5 weeks by 11%. Training lowered the insulin and ghrelin levels, while corticosterone level was increased. Insulin, ghrelin and corticosterone only reached the significant threshold p<0.05. Thus, it seems that exercise, even of low intensity and duration, induces changes on hormones that regulate food intake and limit overweight.

Measuring happiness: from fluctuating happiness to authentic-durable happiness.

On the basis of the theoretical distinction between self-centeredness and selflessness (Dambrun and Ricard, 2011), the main goal of this research was to develop two new scales assessing distinct dimensions of happiness. By trying to maximize pleasures and to avoid displeasures, we propose that a self-centered functioning induces a fluctuating happiness in which phases of pleasure and displeasure alternate repeatedly (i.e., Fluctuating Happiness). In contrast, a selfless psychological functioning postulates the existence of a state of durable plenitude that is less dependent upon circumstances but rather is related to a person’s inner resources and abilities to deal with whatever comes his way in life (i.e., Authentic–Durable Happiness). Using various samples (nu2009=u2009735), we developed a 10-item Scale measuring Subjective Fluctuating Happiness (SFHS) and a 13-item scale assessing Subjective Authentic–Durable Happiness (SA–DHS). Results indicated high internal consistencies, satisfactory test–retest validities, and adequate convergent and discriminant validities with various constructs including a biological marker of stress (salivary cortisol). Consistent with our theoretical framework, while self-enhancement values were related only to fluctuating happiness, self-transcendence values were related only to authentic–durable happiness. Support for the distinction between contentment and inner-peace, two related markers of authentic happiness, also was found.

Influence d'une compétition de rugby sur le taux de cortisol salivaire

Resume Introductionxa0– L’objectif de notre travail a ete de mesurer l’influence d’une competition sportive, en l’occurrence un match de rugby international, sur la concentration de cortisol salivaire. Synthese des faitsxa0– Les concentrations de cortisol ont ete mesurees par technique radio-immunologique sur des prelevements salivaires recueillis au cours d’une competition, ainsi que lors d’une journee de repos.xa0 On constate une augmentation de la concentration de cortisol de 75xa0%, entre le debut et la fin de la competition. Celle-ci reflete a la fois la reponse physiologique et psychologique face a une stimulation stressante. La valeur pre-competitive est egalement plus elevee (85xa0%) que celle mesuree, a la meme heure, le jour de repos. Conclusionxa0– La competition influence de maniere positive la concentration de cortisol salivaire, ce qui temoigne de l’anticipation cognitive des sujets.

Réponses du cortisol et de la testostérone salivaires au cours de la récupération post-compétitive en rugby

Resume Objectifs. – Evaluer les repercussions biologiques de letat de fatigue post-competitive chez les joueurs dune equipe de rugby au cours de la semaine suivant un match international. Methodes et resultats. – Les taux de cortisol et de testosterone salivaires ont ete mesures. On releve une chute des taux de cortisol par rapport aux valeurs mesurees a la meme heure lors dune journee de repos pendant les 4 premiers jours suivant la competition, alors quinversement les taux de testosterone presentent une augmentation. Par consequent, il faut au moins 5xa0jours de recuperation pour que ces deux variables biologiques choisies comme marqueurs de fatigue reviennent a leurs valeurs de base.

Le questionnaire de surentraînement - corrélations avec le cortisol et la testostérone dans le cadre du suivi d'une équipe de haut niveau en rugby

Resume Objectif. – Mesurer un niveau de fatigue chez des joueurs de rugby. Materiels et methodes. – Vingt et un joueurs ont repondu au questionnaire francais de surentrainement elabore par la SFMS et subi une evaluation des taux de cortisol et testosterone salivaires a deux periodes de la saison (T1 et T2). Resultats et conclusion. – Le score obtenu au questionnaire de surentrainement est significativement superieur a T2 par rapport a T1. Limportance de la charge dentrainement et des competitions ont induit une augmentation significative du cortisol et une diminution significative de la testosterone durant la saison. La meilleure correlation entre le score et les taux hormonaux salivaires a ete constatee a 8xa0heures. De ce fait, les taux de testosterone et de cortisol salivaires utilises comme marqueur de fatigue sont a considerer de preference a 8xa0heures.

Effet de l'entraînement et de la compétition sur la réponse du cortisol salivaire chez des gymnastes féminines prépubères

Resume Objectif Il sagissait dune part danalyser les variations de concentrations de cortisol salivaire chez des filles gymnastes prepuberes soumises a un entrainement durant 16 semaines et, dautre part, danalyser la charge physique induite par une competition. Methodes La population etait composee de dix gymnastes sentrainant 11 heures 30 par semaine et de dix sedentaires. Des echantillons salivaires ont ete recueillis lors de la premiere (T1), huitieme (T2), douzieme (T3) et seizieme (T4) semaine de reprise de lentrainement a 8 h et a 17 h. Des prelevements salivaires ont egalement eu lieu le jour dune competition entre T2 et T3. Resultats Comparativement a T1, une elevation des concentrations de cortisol a T2 et T3 a ete notee chez les gymnastes aussi bien a 8 h qua 17 h ( p p p Conclusion Ces resultats suggerent quune augmentation chronique du cortisol liee a une fatigue physique ou mentale apparait en periode de competition. Par ailleurs, meme si la competition induit une elevation de cortisol, celle-ci ne saccompagne pas dun stress anticipatif observe habituellement chez ladulte.