Moderate to vigorous physical activity and sedentary time and cardiometabolic risk factors in children and adolescents.

CONTEXT: Sparse data exist on the combined associations between physical activity and sedentary time with cardiometabolic risk factors in healthy children. OBJECTIVE: To examine the independent and combined associations between objectively measured time in moderate- to vigorous-intensity physical activity (MVPA) and sedentary time with cardiometabolic risk factors. DESIGN, SETTING, AND PARTICIPANTS: Pooled data from 14 studies between 1998 and 2009 comprising 20 871 children (aged 4-18 years) from the International Children's Accelerometry Database. Time spent in MVPA and sedentary time were measured using accelerometry after reanalyzing raw data. The independent associations between time in MVPA and sedentary time, with outcomes, were examined using meta-analysis. Participants were stratified by tertiles of MVPA and sedentary time. MAIN OUTCOME MEASURES: Waist circumference, systolic blood pressure, fasting triglycerides, high-density lipoprotein cholesterol, and insulin. RESULTS: Times (mean [SD] min/d) accumulated by children in MVPA and being sedentary were 30 (21) and 354 (96), respectively. Time in MVPA was significantly associated with all cardiometabolic outcomes independent of sex, age, monitor wear time, time spent sedentary, and waist circumference (when not the outcome). Sedentary time was not associated with any outcome independent of time in MVPA. In the combined analyses, higher levels of MVPA were associated with better cardiometabolic risk factors across tertiles of sedentary time. The differences in outcomes between higher and lower MVPA were greater with lower sedentary time. Mean differences in waist circumference between the bottom and top tertiles of MVPA were 5.6 cm (95% CI, 4.8-6.4 cm) for high sedentary time and 3.6 cm (95% CI, 2.8-4.3 cm) for low sedentary time. Mean differences in systolic blood pressure for high and low sedentary time were 0.7 mm Hg (95% CI, -0.07 to 1.6) and 2.5 mm Hg (95% CI, 1.7-3.3), and for high-density lipoprotein cholesterol, differences were -2.6 mg/dL (95% CI, -1.4 to -3.9) and -4.5 mg/dL (95% CI, -3.3 to -5.6), respectively. Geometric mean differences for insulin and triglycerides showed similar variation. Those in the top tertile of MVPA accumulated more than 35 minutes per day in this intensity level compared with fewer than 18 minutes per day for those in the bottom tertile. In prospective analyses (N = 6413 at 2.1 years' follow-up), MVPA and sedentary time were not associated with waist circumference at follow-up, but a higher waist circumference at baseline was associated with higher amounts of sedentary time at follow-up. CONCLUSION: Higher MVPA time by children and adolescents was associated with better cardiometabolic risk factors regardless of the amount of sedentary time.

Neurally Adjusted Ventilatory Assist (NAVA) improves the matching of diaphragmatic electrical activity and tidal volume in comparison to pressure support (PS) under non invasive ventilation

INTRODUCTION. Patient-ventilator asynchrony is a frequent issue in non invasivemechanical ventilation (NIV) and leaks at the patient-mask interface play a major role in itspathogenesis. NIV algorithms alleviate the deleterious impact of leaks and improve patient-ventilator interaction. Neurally adusted ventilatory assist (NAVA), a neurally triggered modethat avoids interferences between leaks and the usual pneumatic trigger, could further improvepatient-ventilator interaction in NIV patients.OBJECTIVES. To evaluate the feasibility ofNAVAin patients receiving a prophylactic postextubationNIV and to compare the respective impact ofPSVandNAVAwith and withoutNIValgorithm on patient-ventilator interaction.METHODS. Prospective study conducted in 16 beds adult critical care unit (ICU) in a tertiaryuniversity hospital. Over a 2 months period, were included 17 adult medical ICU patientsextubated for less than 2 h and in whom a prophylactic post-extubation NIV was indicated.Patients were randomly mechanically ventilated for 10 min with: PSV without NIV algorithm(PSV-NIV-), PSV with NIV algorithm (PSV-NIV+),NAVAwithout NIV algorithm (NAVANIV-)and NAVA with NIV algorithm (NAVA-NIV+). Breathing pattern descriptors, diaphragmelectrical activity, leaks volume, inspiratory trigger delay (Tdinsp), inspiratory time inexcess (Tiexcess) and the five main asynchronies were quantified. Asynchrony index (AI) andasynchrony index influenced by leaks (AIleaks) were computed.RESULTS. Peak inspiratory pressure and diaphragm electrical activity were similar in thefour conditions. With both PSV and NAVA, NIV algorithm significantly reduced the level ofleak (p\0.01). Tdinsp was not affected by NIV algorithm but was shorter in NAVA than inPSV (p\0.01). Tiexcess was shorter in NAVA and PSV-NIV+ than in PSV-NIV- (p\0.05).The prevalence of double triggering was significantly lower in PSV-NIV+ than in NAVANIV+.As compared to PSV,NAVAsignificantly reduced the prevalence of premature cyclingand late cycling while NIV algorithm did not influenced premature cycling. AI was not affectedby NIV algorithm but was significantly lower in NAVA than in PSV (p\0.05). AIleaks wasquasi null with NAVA and significantly lower than in PSV (p\0.05).CONCLUSIONS. NAVA is feasible in patients receiving a post-extubation prophylacticNIV. NAVA and NIV improve patient-ventilator synchrony in different manners. NAVANIV+offers the best patient-ventilator interaction. Clinical studies are required to assess thepotential clinical benefit of NAVA in patients receiving NIV.

A repeated GGA motif is critical for the activity and stability of the riboregulator RsmY of Pseudomonas fluorescens.

The riboregulator RsmY of Pseudomonas fluorescens strain CHA0 is an example of small regulatory RNAs belonging to the global Rsm/Csr regulatory systems controlling diverse cellular processes such as glycogen accumulation, motility, or formation of extracellular products in various bacteria. By binding multiple molecules of the small regulatory protein RsmA, RsmY relieves the negative effect of RsmA on the translation of several target genes involved in the biocontrol properties of strain CHA0. RsmY and functionally related riboregulators have repeated GGA motifs predicted to be exposed in single-stranded regions, notably in the loops of hairpins. The secondary structure of RsmY was corroborated by in vivo cleavage with lead acetate. RsmY mutants lacking three or five (out of six) of the GGA motifs showed reduced ability to derepress the expression of target genes in vivo and failed to bind the RsmA protein efficiently in vitro. The absence of GGA motifs in RsmY mutants resulted in reduced abundance of these transcripts and in a shorter half-life (< or = 6 min as compared with 27 min for wild type RsmY). These results suggest that both the interaction of RsmY with RsmA and the stability of RsmY strongly depend on the GGA repeats and that the ability of RsmY to interact with small regulatory proteins such as RsmA may protect this RNA from degradation.

Cytochrome P450 1A2 activity and inducibility: impact of smoking, smoking cessation and genetic polymorphisms

Aims: Cytochrome P4501A2 (CYP1A2) is involved in the metabolism of severaldrugs (clozapine, olanzapine, theopylline, caffeine, etc) and is induced by smoking.This can result in decreased plasma levels of drugs metabolized by thisisoenzyme, causing a decrease in therapeutic response. After quitting smoking,increased plasma levels can lead to adverse effects of the concerned drugs, such asconfusion and seizures, described under clozapine treatment. The present studyaimed to examine the variation of CYP1A2 activity in a large group of smokersbefore and after smoking cessation. Moreover, we aimed to determine whethergenetic polymorphisms of CYP1A2 gene could influence the inducibility ofCYP1A2. Methods: CYP1A2 activity was determined by the paraxanthine/caffeineratio in 194 smokers and in 118 of them being abstinent during a 4-weekperiod. Participants were genotyped for CYP1A2*1F (rs762551), *1D(rs35694136) and *1C (rs2069514) polymorphisms. Results: Smokers had higherCYP1A2 activity (1.55-fold; p < 0.0001). Individual change of CYP1A2 activityafter smoking cessation ranged from 1.0-fold (no change) to 7.3-fold decreasedactivity. In five participants with low initial CYP1A2 activity, an increase wasobserved after smoking cessation. During smoking, CYP1A2*1F (p = 0.005), CYP1A2*1D (p = 0.014), the number of cigarettes/day (p = 0.012), contraceptives use(p < 0.001) and - 163A/- 2467T/- 3860G haplotype (p = 0.002) influencedCYP1A2 activity, while after quitting smoking, CYP1A2*1F (p = 0.017) and contraceptives(p = 0.05) did. No influence of CYP1A2 polymorphisms on the inducibilityof CYP1A2 was observed. Conclusion: Higher CYP1A2 activity wasmeasured in smokers, but with a large interindividual variability of its inductionby smoking. Careful clinical management with the help of therapeutic drug monitoringis therefore needed for patients receiving drugs which are metabolized byCYP1A2, who stop or start smoking. Unidentified genetic variations in theCYP1A2 gene and/or in other genes controlling CYP1A2 activity and other environmentalfactors could be responsible of the observed differences in CYP1A2enzymatic activity and inducibility.

Activity and exploratory behavior after lesions of the medial entorhinal cortex in the woodmouse (Apodemus sylvaticus).

The effects of bilateral electrolytic lesions of the entorhinal cortex were studied in male adult woodmice. Experiments were designed to allow separate analysis of the basal activity level and exploratory behavior. Activity recording was conducted in three situations: (a) 24-hr wheel running in the home cage pre- and postoperatively; (b) 24-hr activity composition in a large enclosure over 4 days, 5 to 9 days postoperatively; and (c) sequence and duration of visits in a residential plus maze 11 to 14 days postoperatively. Medial entorhinal cortex lesion involving the para- and presubiculum increased the 24-hr amount of movements in the enclosure (b) without increasing wheel running in any situation (a or b). This lesion also enhanced the locomotor reactivity to being introduced into the plus maze and impaired exploratory behavior. This last effect was equally apparent when the whole situation was new or when part of the familiar maze was modified. Lesioned woodmice did notice the new element but did not show active focalization of their behavior on that element. Data showed that lesion induced hyperactivity and changes of exploratory behavior were not necessarily associated. Novelty detection was performed but it is not clear now on what information this discrimination was based.

Influence activity and the organization of research and development

The organizational design of research and development conditions theincentives of the researchers of the research project. In particular,the organizational form determines the allocation of effort of theresearcher between time spent on research and time spent lobbying management. Researchers prefer to spend their time on research. However,the researchers only get utility from performing research if theproject is approved for its full duration. Spending time lobbyingmanagement for the continuation of the researcher s project increasesthe probability that the management observes a favorable signal aboutthe project. Organizing a research joint venture increases theflexibility of the organizational form with respect to the continuationdecision. For low correlation between the signals of the partners aboutthe expected profitability of the project, we find that the organizationof a research joint venture reduces influence activity by the researchersand increases expected profits of the partners. For high correlationbetween the signals, internal research projects lower influence activityby the researchers. We try to relate the correlation of the partnerssignals to the characteristics of basic research versus more appliedresearch projects, and find that the model is consistent with theobservation that research joint ventures seem involved in more basicresearch projects compared to internal R&D departments, whichconcentrate on more applied research.

Impact of small variations in temperature and humidity on the reproductive activity and survival of Aedes aegypti (Diptera, Culicidae)

In short space of time increase in temperature and rainfall can affect vector populations and, consequently, the diseases for them transmitted. The present study analyzed the effect of small temperature and humidity variations on the fecundity, fertility and survival of Aedes aegypti. These parameters were analyzed using individual females at temperatures ranging from 23 to 27 °C (mean 25 °C); 28 to 32 °C (mean 30 °C) and 33 to 37 °C (mean 35 ºC) associated to 60±8% and 80±6% relative humidity. Females responded to an increase in temperature by reducing egg production, oviposition time and changing oviposition patterns. At 25 ºC and 80% relative humidity, females survived two-fold more and produced 40% more eggs when compared to those kept at 35 ºC and 80% relative humidity. However, in 45% of females kept at 35 ºC and 60% relative humidity oviposition was inhibited and only 15% females laid more than 100 eggs, suggesting that the intensity of the temperature effect was influenced by humidity. Gradual reductions in egg fertility at 60% relative humidity were observed with the increase in temperature, although such effect was not found in the 80% relative humidity at 25 º C and 30 º C. These results suggest that the reduction in population densities recorded in tropical areas during seasons when temperatures reach over 35 ºC is likely to be strongly influenced by temperature and humidity, with a negative effect on several aspects of mosquito biology.

Exercice physique et artériopathie oblitérante des membres inférieurs [Physical activity and peripheral arterial obstructive disease]

Intermittent claudication (IC) is the most common clinical manifestation of atherosclerotic peripheral arterial disease. Exercise training plays a major role in treating patients with IC. Regular exercise increases functional walking capacity, reduces cardiovascular mortality and improves quality of life. This seems to be achieved by: favorable effect on cardiovascular risk factors, anti-inflammatory effect, increased collateral blood flux, improved rheology profile, endothelial function, fibrinolysis, and muscular metabolism. However, exact mechanisms underlying beneficial effect of exercise remain largely unknown. Exercise modalities will be discussed in this article.

Physical activity and pregnancy: cardiovascular adaptations, recommendations and pregnancy outcomes.

Regular physical activity is associated with improved physiological, metabolic and psychological parameters, and with reduced risk of morbidity and mortality. Current recommendations aimed at improving the health and well-being of nonpregnant subjects advise that an accumulation of > or =30 minutes of moderate physical activity should occur on most, if not all, days of the week. Regardless of the specific physiological changes induced by pregnancy, which are primarily developed to meet the increased metabolic demands of mother and fetus, pregnant women benefit from regular physical activity the same way as nonpregnant subjects. Changes in submaximal oxygen uptake (VO(2)) during pregnancy depend on the type of exercise performed. During maternal rest or submaximal weight-bearing exercise (e.g. walking, stepping, treadmill exercise), absolute maternal VO(2) is significantly increased compared with the nonpregnant state. The magnitude of change is approximately proportional to maternal weight gain. When pregnant women perform submaximal weight-supported exercise on land (e.g. level cycling), the findings are contradictory. Some studies reported significantly increased absolute VO(2), while many others reported unchanged or only slightly increased absolute VO(2) compared with the nonpregnant state. The latter findings may be explained by the fact that the metabolic demand of cycle exercise is largely independent of the maternal body mass, resulting in no absolute VO(2) alteration. Few studies that directly measured changes in maternal maximal VO(2) (VO(2max)) showed no difference in the absolute VO(2max) between pregnant and nonpregnant subjects in cycling, swimming or weight-bearing exercise. Efficiency of work during exercise appears to be unchanged during pregnancy in non-weight-bearing exercise. During weight-bearing exercise, the work efficiency was shown to be improved in athletic women who continue exercising and those who stop exercising during pregnancy. When adjusted for weight gain, the increased efficiency is maintained throughout the pregnancy, with the improvement being greater in exercising women. Regular physical activity has been proven to result in marked benefits for mother and fetus. Maternal benefits include improved cardiovascular function, limited pregnancy weight gain, decreased musculoskeletal discomfort, reduced incidence of muscle cramps and lower limb oedema, mood stability, attenuation of gestational diabetes mellitus and gestational hypertension. Fetal benefits include decreased fat mass, improved stress tolerance, and advanced neurobehavioural maturation. In addition, few studies that have directly examined the effects of physical activity on labour and delivery indicate that, for women with normal pregnancies, physical activity is accompanied with shorter labour and decreased incidence of operative delivery. However, a substantial proportion of women stop exercising after they discover they are pregnant, and only few begin participating in exercise activities during pregnancy. The adoption or continuation of a sedentary lifestyle during pregnancy may contribute to the development of certain disorders such as hypertension, maternal and childhood obesity, gestational diabetes, dyspnoea, and pre-eclampsia. In view of the global epidemic of sedentary behaviour and obesity-related pathology, prenatal physical activity was shown to be useful for the prevention and treatment of these conditions. Further studies with larger sample sizes are required to confirm the association between physical activity and outcomes of labour and delivery.

IL28B polymorphisms leading to poor response to treatment are associated with low necroinflammatory activity and slow fibrosis progression in HCV genotype non-1-infected patients

Background and Aims: Genetic polymorphisms near IL28Bhave been associated with spontaneous and treatment-inducedclearance of hepatitis C virus (HCV). This is believed to proceed viathe appropriate activation of innate and adaptive immune responsestargeting infected hepatocytes. Intrahepatic inflammation is thereflection of the host cell immune response, but its relationshipwith IL28B polymorphisms has yet to be fully appreciated.Methods: We analyzed the association of IL28B polymorphismswith Metavir activity (≥1) and fibrosis scores (≥2) in 1114 HCVinfectedCaucasian patients enrolled in the Swiss Hepatitis C CohortStudy (629, 127, 268 and 110 infected with HCV genotype 1, 2, 3and 4, respectively). In a subgroup of 915 patients with an estimateddate of infection, the association between IL28B polymorphismsand fibrosis progression rate (FPR > median) was assessed. Singlenucleotide polymorphisms (SNPs) of interest were extracted froma dataset generated in a genome-wide association study and/orgenotyped by TaqMan assay. Associations of alleles with differentdegrees of activity and fibrosis were evaluated using an additivemodel of inheritance by multivariate logistic regression, accountingfor all relevant covariates.Results: The rare G allele at marker rs8099917 was associated withlower activity (P = 0.008) and fibrosis (P = 0.01), as well as slower FPR(P = 0.02). Most striking associations were observed among patientsinfected with non-1 genotypes (P = 0.002 for activity, P = 0.002 forfibrosis and P = 0.005 for FPR). In genotype 1-infected patients, theassociation with activity was observed only in the recessive model(P = 0.04), whereas other associations were not significant (P = 0.7for fibrosis and P = 0.4 for FPR).Conclusions: In chronic hepatitis C, IL28B polymorphisms linkedwith a poor virological response to therapy are also associated withreduced intrahepatic necroinflammation and slower liver diseaseprogression. These observations underscore the role played by thehost immune response in clearing HCV, especially in patients withHCV genotypes non-1.

Effect of the environment inside and outside the cage on the activity and behaviour test performance of silver foxes

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