How about running on Mars? Influence of sensorimotor coherence on running and spatial perception in simulated reduced gravity

Motor control, including locomotion, strongly depends on the gravitational field. Recent developments such as lower-body positive pressure treadmills (LBPPT) have enabled studies on Earth about the effects of reduced body weight (BW) on walking and running, up to 60% BW. The present experiment was set up to further investigate adaptations to a more naturalistic simulated hypogravity, mimicking a Martian environment with additional visual information during running sessions on LBPPT. Twenty-nine participants performed three sessions of four successive five-min runs at preferred speed, alternating Earth- or simulated Mars-like gravity (100% vs. 38% BW). They were displayed visual scenes using a virtual reality headset to assess the effects of coherent visual flow while running. Running performance was characterized by normal ground reaction force and pelvic accelerations. The perceived upright and vection (visually-induced self-motion sensation)in dynamic visual environments were also investigated at the end of the different sessions. We found that BW reduction induced biomechanical adaptations independently of the visual context. Active peak force and stance time decreased, while flight time increased. Strong inter-individual differences in braking and push-off times appeared at 38% BW, which were not systematically observed in our previous studies at 80% and 60% BW. Additionally, the importance given to dynamic visual cues in the perceived upright diminished at 38% BW, suggesting an increased reliance on the egocentric body axis as a reference for verticality when the visual context is fully coherent with the previous locomotor activity. Also, while vection was found to decrease in case of a coherent visuomotor coupling at 100% BW (i.e., post-exposure influence), it remained unaffected by the visual context at 38% BW. Overall, our findings suggested that locomotor and perceptual adaptations were not similarly impacted, depending on the -simulated- gravity condition and visual context

The Nutritional Induction of COUP-TFII Gene Expression in Ventromedial Hypothalamic Neurons Is Mediated by the Melanocortin Pathway

BACKGROUND: The nuclear receptor chicken ovalbumin upstream promoter transcription factor II (COUP-TFII) is an important coordinator of glucose homeostasis. We report, for the first time, a unique differential regulation of its expression by the nutritional status in the mouse hypothalamus compared to peripheral tissues. METHODOLOGY/PRINCIPAL FINDINGS: Using hyperinsulinemic-euglycemic clamps and insulinopenic mice, we show that insulin upregulates its expression in the hypothalamus. Immunofluorescence studies demonstrate that COUP-TFII gene expression is restricted to a subpopulation of ventromedial hypothalamic neurons expressing the melanocortin receptor. In GT1-7 hypothalamic cells, the MC4-R agonist MTII leads to a dose dependant increase of COUP-TFII gene expression secondarily to a local increase in cAMP concentrations. Transfection experiments, using a COUP-TFII promoter containing a functional cAMP responsive element, suggest a direct transcriptional activation by cAMP. Finally, we show that the fed state or intracerebroventricular injections of MTII in mice induce an increased hypothalamic COUP-TFII expression associated with a decreased hepatic and pancreatic COUP-TFII expression. CONCLUSIONS/SIGNIFICANCE: These observations strongly suggest that hypothalamic COUP-TFII gene expression could be a central integrator of insulin and melanocortin signaling pathway within the ventromedial hypothalamus. COUP-TFII could play a crucial role in brain integration of circulating signal of hunger and satiety involved in energy balance regulation

COUP-TFII Controls Mouse Pancreatic β-Cell Mass through GLP-1-β-Catenin Signaling Pathways

Background: The control of the functional pancreatic beta-cell mass serves the key homeostatic function of releasing the right amount of insulin to keep blood sugar in the normal range. It is not fully understood though how beta-cell mass is determined

Total and partial cancer prevalence in the adult French population in 2008.

BACKGROUND: To provide estimations of partial and total prevalence of 24 cancer sites in France in 2008. The estimations of partial prevalence were compared with the previous estimations for 2002. METHODS: Nationwide estimations of incidence and survival data from cancer registries were used for partial prevalence. Nationwide incidence and mortality data were used to estimate total prevalence. RESULTS: At the end of 2008, in France, nearly 3 million people still alive had received a diagnosis of cancer. Of all prevalent cases, 36% were diagnosed 0 to 5 years earlier and 43% diagnosed 6 to 10 years earlier. The cancer sites with the highest prevalence were the prostate, the breast, and the colon-rectum. The changes in partial prevalence over 5 years (2002 to 2008) were considerable (+244,000 cases) and deemed to be highly related to changes in incidence. CONCLUSION: The present estimations update the French prevalence data and highlight the burden of cancer in the population, especially in the elderly. The methods of this study had the advantage of using recent incidence and survival data, which is necessary to show sudden changes in incidence trends and changes in survival that impact prevalence

La reprogrammation métabolique des carcinomes hépatocellulaires β-caténine mutés

International audienc

Quand santé et mobilité s'entremêlent. L'encadrement de proximité au cœur des enjeux de début de parcours des ouvriers de production de la construction aéronautique

International audienceThis article is about a research in progress in an aircraft manufacturer, carried out through collaboration between researchers and internal ergonomists. The objective is to understand the link between health, experience and career history for workers. In this aim, we match statistic and qualitative analysis, focusing on work determinants and regulations carried out by team and operational leaders. How do team leaders combine performance and operators’career temporalities? In the article we develop this point.Cette communication porte sur une recherche en cours dans un établissement de la construction aéronautique, impliquant un partenariat entre chercheurs externes et ergonomes du site. En combinant des analyses quantitatives de données de l'entreprise et des analyses qualitatives, elle vise à comprendre la façon dont se construisent les liens entre santé, expérience et parcours professionnels des ouvriers de production. Le projet analyse les déterminants du travail en jeu et les modes de régulation entre acteurs de différents niveaux et dans l'activité. Dans cette perspective, le projet porte une attention particulière aux rôles de l'encadrement de proximité et à leurs marges de manoeuvre pour combiner temporalité de la performance et temporalité des parcours

Quand santé et mobilité s'entremêlent. L'encadrement de proximité au cœur des enjeux de début de parcours des ouvriers de production de la construction aéronautique

International audienceThis article is about a research in progress in an aircraft manufacturer, carried out through collaboration between researchers and internal ergonomists. The objective is to understand the link between health, experience and career history for workers. In this aim, we match statistic and qualitative analysis, focusing on work determinants and regulations carried out by team and operational leaders. How do team leaders combine performance and operators’career temporalities? In the article we develop this point.Cette communication porte sur une recherche en cours dans un établissement de la construction aéronautique, impliquant un partenariat entre chercheurs externes et ergonomes du site. En combinant des analyses quantitatives de données de l'entreprise et des analyses qualitatives, elle vise à comprendre la façon dont se construisent les liens entre santé, expérience et parcours professionnels des ouvriers de production. Le projet analyse les déterminants du travail en jeu et les modes de régulation entre acteurs de différents niveaux et dans l'activité. Dans cette perspective, le projet porte une attention particulière aux rôles de l'encadrement de proximité et à leurs marges de manoeuvre pour combiner temporalité de la performance et temporalité des parcours