Effect of physical exercise on glycogen turnover and net substrate utilization according to the nutritional state.

To determine the metabolic effects of a single bout of exercise performed after a meal or in the fasting state, nine healthy subjects were studied over two 8-h periods during which net substrate oxidation was monitored by indirect calorimetry. On one occasion, exercise was performed 90 min after ingestion of a meal labeled with [U-13C]glucose [protocol meal-exercise (M-E)]. On the second occasion, exercise was performed after an overnight fast and was followed 30 min later by ingestion of an identical meal [protocol exercise-meal (E-M)]. Energy balances were similar in both protocols, but carbohydrate balance was positive (42.2 +/- 5.1 g), and lipid balance was negative (-11.1 +/- 2.0) during E-M, whereas they were nearly even during M-E. Total glycogen synthesis was calculated as carbohydrate intake minus oxidation of exogenous 13C-labeled carbohydrate (calculated from 13CO2 production). Total glycogen synthesis was increased by 90% (from 47.6 +/- 3.8 to 90.7 +/- 5.4 g, P < 0.0001) during E-M vs. M-E. Endogenous glycogen breakdown was calculated as net carbohydrate oxidation minus oxidation of exogenous carbohydrate and was increased by 44% (from 35.8 +/- 5.6 to 51.7 +/- 6.6 g, P < 0.004) during E-M. It is concluded that exercise performed in the fasting state stimulates glycogen turnover and fat oxidation.

Physical interaction between bacterial heat shock protein (Hsp) 90 and Hsp70 chaperones mediates their cooperative action to refold denatured proteins.

In eukaryotes, heat shock protein 90 (Hsp90) is an essential ATP-dependent molecular chaperone that associates with numerous client proteins. HtpG, a prokaryotic homolog of Hsp90, is essential for thermotolerance in cyanobacteria, and in vitro it suppresses the aggregation of denatured proteins efficiently. Understanding how the non-native client proteins bound to HtpG refold is of central importance to comprehend the essential role of HtpG under stress. Here, we demonstrate by yeast two-hybrid method, immunoprecipitation assays, and surface plasmon resonance techniques that HtpG physically interacts with DnaJ2 and DnaK2. DnaJ2, which belongs to the type II J-protein family, bound DnaK2 or HtpG with submicromolar affinity, and HtpG bound DnaK2 with micromolar affinity. Not only DnaJ2 but also HtpG enhanced the ATP hydrolysis by DnaK2. Although assisted by the DnaK2 chaperone system, HtpG enhanced native refolding of urea-denatured lactate dehydrogenase and heat-denatured glucose-6-phosphate dehydrogenase. HtpG did not substitute for DnaJ2 or GrpE in the DnaK2-assisted refolding of the denatured substrates. The heat-denatured malate dehydrogenase that did not refold by the assistance of the DnaK2 chaperone system alone was trapped by HtpG first and then transferred to DnaK2 where it refolded. Dissociation of substrates from HtpG was either ATP-dependent or -independent depending on the substrate, indicating the presence of two mechanisms of cooperative action between the HtpG and the DnaK2 chaperone system.

The incidence and selection of multiple mating in plants.

Mating with more than one pollen donor, or polyandry, is common in land plants. In flowering plants, polyandry occurs when the pollen from different potential sires is distributed among the fruits of a single individual, or when pollen from more than one donor is deposited on the same stigma. Because polyandry typically leads to multiple paternity among or within fruits, it can be indirectly inferred on the basis of paternity analysis using molecular markers. A review of the literature indicates that polyandry is probably ubiquitous in plants except those that habitually self-fertilize, or that disperse their pollen in pollen packages, such as polyads or pollinia. Multiple mating may increase plants' female component by alleviating pollen limitation or by promoting competition among pollen grains from different potential sires. Accordingly, a number of traits have evolved that should promote polyandry at the flower level from the female's point of view, e.g. the prolongation of stigma receptivity or increases in stigma size. However, many floral traits, such as attractiveness, the physical manipulation of pollinators and pollen-dispensing mechanisms that lead to polyandrous pollination, have probably evolved in response to selection to promote male siring success in general, so that polyandry might often best be seen as a by-product of selection to enhance outcross siring success. In this sense, polyandry in plants is similar to geitonogamy (selfing caused by pollen transfer among flowers of the same plant), because both polyandry and geitonogamy probably result from selection to promote outcross siring success, although geitonogamy is almost always deleterious while polyandry in plants will seldom be so.

Neuroendocrine regulation and central dopamine (DA) systems in physical and psychological stress

Physical and psychological stress cause different patterns of changes in the fluorescence intensity of nigral and tuberoinfundibular DA neurons which point to changes in neuronal activity. In order to investigate possible interactions between alpha-MSH (alpha-melanotropin) and DA systems in stress, systemic and intraventricular injections of antiserum against alpha-MSH were made. The functional state of DA neurons was assessed by histochemical microfluorimetry and hormone levels were measured by radioimmunossay. Antiserum against alpha-MSH was found to affect the functional state of DA neurons, but only thorugh the intravenous route. Under physical stress i.v. injection of antiserum against alpha-MSH was accompanied by elevated levels of activity of the DA neurons of the substantia nigra. An intraventricular injection of the same antiserum was ineffective. In psychological stress, an effect was again seen only after intravenous injection of antiserum against alpha-MSH. In this situation, the activity in DA cell groups of the substantia nigra, ventral tegmental area and tubero-infundibular system was increased after antiserum injection. Possible influences from manipulations were checked; certain effects which depended upon experimental situation were noted. Our data suggest a modulatory influence of circulating alpha-MSH on the functional state of central DA systems.

Comparisons of intensity-duration patterns of physical activity in the US, Jamaica and 3 African countries.

BACKGROUND: This difference in how populations living in low-, middle or upper-income countries accumulate daily PA, i.e. patterns and intensity, is an important part in addressing the global PA movement. We sought to characterize objective PA in 2,500 participants spanning the epidemiologic transition. The Modeling the Epidemiologic Transition Study (METS) is a longitudinal study, in 5 countries. METS seeks to define the association between physical activity (PA), obesity and CVD risk in populations of African origin: Ghana (GH), South Africa (SA), Seychelles (SEY), Jamaica (JA) and the US (suburban Chicago). METHODS: Baseline measurements of objective PA, SES, anthropometrics and body composition, were completed on 2,500 men and women, aged 25-45 years. Moderate and vigorous PA (MVPA, min/d) on week and weekend days was explored ecologically, by adiposity status and manual labor. RESULTS: Among the men, obesity prevalence reflected the level of economic transition and was lowest in GH (1.7%) and SA (4.8%) and highest in the US (41%). SA (55%) and US (65%) women had the highest levels of obesity, compared to only 16% in GH. More men and women in developing countries engaged in manual labor and this was reflected by an almost doubling of measured MPVA among the men in GH (45 min/d) and SA (47 min/d) compared to only 28 min/d in the US. Women in GH (25 min/d), SA (21 min/d), JA (20 min/d) and SEY (20 min/d) accumulated significantly more MPVA than women in the US (14 min/d), yet this difference was not reflected by differences in BMI between SA, JA, SEY and US. Moderate PA constituted the bulk of the PA, with no study populations except SA men accumulating > 5 min/d of vigorous PA. Among the women, no sites accumulated >2 min/d of vigorous PA. Overweight/obese men were 22% less likely to engage in manual occupations. CONCLUSION: While there is some association for PA with obesity, this relationship is inconsistent across the epidemiologic transition and suggests that PA policy recommendations should be tailored for each environment.

Promotion of physical activity in the primary care setting : the situation in Switzerland

Although many harmful effects of a sedentary lifestyle on health are well known, we still need to better understand how regular physical activity in the general population can be promoted effectively. Among the currently explored strategies, screening for sedentary lifestyle and promoting physical activity in the primary care setting seem promising. Despite recommendations from governmental agencies and professional associations in favor of physical activity counseling, this approach has not been widely adopted so far. This article summarizes the steps taken in Switzerland with the aim of developing physical activity counseling in the primary care setting. It describes how the early implication of primary care physicians influenced in a concrete way the development of the project.

Childhood sexual and physical abuse: age at exposure modulates impact on functional outcome in early psychosis patients.

BACKGROUND: Evidence suggests a relationship between exposure to trauma during childhood and functional impairments in psychotic patients. However, the impact of age at the time of exposure has been understudied in early psychosis (EP) patients. METHOD: Two hundred and twenty-five patients aged 18-35 years were assessed at baseline and after 2, 6, 18, 24, 30 and 36 months of treatment. Patients exposed to sexual and/or physical abuse (SPA) were classified according to age at the time of first exposure (Early SPA: before age 11 years; Late SPA: between ages 12 and 15 years) and then compared to patients who were not exposed to such trauma (Non-SPA). The functional level in the premorbid phase was measured with the Premorbid Adjustment Scale (PAS) and with the Global Assessment of Functioning (GAF) scale and the Social and Occupational Functioning Assessment Scale (SOFAS) during follow-up. RESULTS: There were 24.8% of patients with a documented history of SPA. Late SPA patients were more likely to be female (p = 0.010). Comparison with non-SPA patients revealed that: (1) both Early and Late SPA groups showed poorer premorbid social functioning during early adolescence, and (2) while patients with Early SPA had poorer functional level at follow-up with lower GAF (p = 0.025) and lower SOFAS (p = 0.048) scores, Late SPA patients did not. CONCLUSION: Our results suggest a link between exposure to SPA and the later impairment of social functioning before the onset of the disease. EP patients exposed to SPA before age 12 may present long-lasting functional impairment, while patients exposed at a later age may improve in this regard and have a better functional outcome.

Physical Activity and Snus: Is There a Link?

The study aimed at assessing the link between physical activity (PA), sports activity and snus use among young men in Switzerland. Data from the Cohort Study on Substance Use Risk Factors (C-SURF) were used to measure PA with the International Physical Activity Questionnaire and sports activity with a single item. Multivariate logistic regression analysis was conducted to measure the association between snus use, PA and sports activity. Similar models were run for smoking and snuff use. Snus use increased in a dose-response association with PA (high level: OR = 1.72; 95% CI 1.16-2.55) and with individuals exercising once a week or more often (OR = 1.65; 95% CI 1.26-2.16; p < 0.001) or almost every day (OR = 2.27; 95% CI 1.72-3.01; p < 0.001) in separate models. Entered simultaneously, only sports and exercise maintained a basically unchanged significant dose-response relationship, whereas PA became non-significant. A non-significant dose-response relation was found for cigarette smoking and snuff use, indicating that the association with sport is specific to snus and not to tobacco use in general or smokeless tobacco in particular. This study showed that the association between snus use and sports is not specific to Nordic countries.

Objectively measured physical activity and sedentary time in youth: the International children's accelerometry database (ICAD).

BACKGROUND: Physical activity and sedentary behaviour in youth have been reported to vary by sex, age, weight status and country. However, supporting data are often self-reported and/or do not encompass a wide range of ages or geographical locations. This study aimed to describe objectively-measured physical activity and sedentary time patterns in youth. METHODS: The International Children's Accelerometry Database (ICAD) consists of ActiGraph accelerometer data from 20 studies in ten countries, processed using common data reduction procedures. Analyses were conducted on 27,637 participants (2.8-18.4 years) who provided at least three days of valid accelerometer data. Linear regression was used to examine associations between age, sex, weight status, country and physical activity outcomes. RESULTS: Boys were less sedentary and more active than girls at all ages. After 5 years of age there was an average cross-sectional decrease of 4.2 % in total physical activity with each additional year of age, due mainly to lower levels of light-intensity physical activity and greater time spent sedentary. Physical activity did not differ by weight status in the youngest children, but from age seven onwards, overweight/obese participants were less active than their normal weight counterparts. Physical activity varied between samples from different countries, with a 15-20 % difference between the highest and lowest countries at age 9-10 and a 26-28 % difference at age 12-13. CONCLUSIONS: Physical activity differed between samples from different countries, but the associations between demographic characteristics and physical activity were consistently observed. Further research is needed to explore environmental and sociocultural explanations for these differences.

Childhood sexual and physical abuse : age at exposure modulates impact on functional outcome in early psychosis patients

Introduction : La littérature suggère un lien entre l'exposition à des expériences traumatiques durant l'enfance et des déficits dans le niveau de fonctionnement chez des patients souffrant de psychose. Par contre, l'impact de l'âge au moment de l'exposition à ces expériences n'a pas été investigué chez des patients dans leur phase précoce de la psychose. Méthodes : Deux cents vingt-cinq patients âgés entre 18 et 35 ans ont été évalués au moment de leur entrée dans un programme thérapeutique spécialisé pour la psychose débutante (TIPP), et après 2, 6, 12, 18, 24, 30 et 36 mois de traitement. Les patients exposés à des abus sexuel et/ou physiques (SPA) ont été classifiés selon l'âge au moment de la première exposition (Early-SPA : avant 11 ans d'âge; Late-SPA : entre 12 et 15 ans d'âge) et ils ont été comparés à des patients qui n'ont jamais été exposés à une telle expérience (Non-SPA). Le niveau de fonctionnement dans la phase premorbide a été mesuré avec la Premorbid Adjustment Scale (PAS) et avec les échelles Global Assessment of Functioning (GAF) et Social and Occupational Functionning Assessment Scale (SOFAS) durant le suivi thérapeutique. Résultats : 24.8 % des patients ont été exposés à SPA. Les patients dans le groupe Late-SPA étaient plus souvent des femmes (p=0.010). Les comparaisons avec les patients dans le groupe Non-SPA ont révélé que : (1) Les patients dans le groupe Early et Late-SPA ont montré un moins bon niveau de fonctionnement social premorbide durant l'adolescence précoce, et (2) alors que les patients dans le groupe Early-SPA ont présenté un moins bon niveau de fonctionnement durant tout le suivi selon les scores de GAF (p=0.025) et SOFAS (p=0.048), les patients dans le groupe Late-SPA n'ont pas montré telles différences avec le groupe non exposé. Conclusion : Nos résultats suggèrent un lien entre l'exposition à SPA et une altération ultérieure de niveau de fonctionnement social, avant l'apparition de la maladie. Les patients dans leur phase précoce de la psychose exposés à SPA avant l'âge de 12 ans ont des altérations fonctionnelles durables, alors que les patients exposés à SPA plus tardivement semblent s'améliorer à ce niveau et montrent une meilleure capacité de récupération.

Association of car ownership and physical activity across the spectrum of human development : Modeling the Epidemiologic Transition Study (METS).

BACKGROUND: Variations in physical activity (PA) across nations may be driven by socioeconomic position. As national incomes increase, car ownership becomes within reach of more individuals. This report characterizes associations between car ownership and PA in African-origin populations across 5 sites at different levels of economic development and with different transportation infrastructures: US, Seychelles, Jamaica, South Africa, and Ghana. METHODS: Twenty-five hundred adults, ages 25-45, were enrolled in the study. A total of 2,101 subjects had valid accelerometer-based PA measures (reported as average daily duration of moderate to vigorous PA, MVPA) and complete socioeconomic information. Our primary exposure of interest was whether the household owned a car. We adjusted for socioeconomic position using household income and ownership of common goods. RESULTS: Overall, PA levels did not vary largely between sites, with highest levels in South Africa, lowest in the US. Across all sites, greater PA was consistently associated with male gender, fewer years of education, manual occupations, lower income, and owning fewer material goods. We found heterogeneity across sites in car ownership: after adjustment for confounders, car owners in the US had 24.3 fewer minutes of MVPA compared to non-car owners in the US (20.7 vs. 45.1 minutes/day of MVPA); in the non-US sites, car-owners had an average of 9.7 fewer minutes of MVPA than non-car owners (24.9 vs. 34.6 minutes/day of MVPA). CONCLUSIONS: PA levels are similar across all study sites except Jamaica, despite very different levels of socioeconomic development. Not owning a car in the US is associated with especially high levels of MVPA. As car ownership becomes prevalent in the developing world, strategies to promote alternative forms of active transit may become important.