Habitual physical activity and physical activity intensity: their relation to body composition in 5.0-10.5 year old children

Background: Concerns of a decrease in physical activity levels (PALs) of children and a concurrent increase in childhood obesity exist worldwide. The exact relation between these two parameters however has as yet to be fully defined in children. Objective: This study examined the relation in 47 children, aged 5–10.5 y (mean age 8.4plusminus0.9 y) between habitual physical activity, minutes spent in moderate, vigorous and hard intensity activity and body composition parameters. Design: Total energy expenditure (TEE) was calculated using the doubly labelled water technique and basal metabolic rate (BMR) was predicted from Schofield's equations. PAL was determined by PAL=TEE/BMR. Time spent in moderate, vigorous and hard intensity activity was determined by accelerometry, using the Tritrac-R3D. Body fatness and body mass index (BMI) were used as the two measures of body composition. Results: Body fat and BMI were significantly inversely correlated with PAL (r=-0.43, P=0.002 and r=-0.45, P=0.001). Times spent in vigorous activity and hard activity were significantly correlated to percentage body fat (r=-0.44, P=0.004 and r=-0.39, P=0.014), but not BMI. Children who were in the top tertiles for both vigorous activity and hard activity had significantly lower body fat percentages than those in the middle and lowest tertiles. Moderate intensity activity was not correlated with measures of body composition. Conclusions: As well as showing a significant relation between PAL and body composition, these data intimate that there may be a threshold of intensity of physical activity that is influential on body fatness. In light of world trends showing increasing childhood obesity, this study supports the need to further investigate the importance of physical activity for children.

Print versus website physical activity programs: A randomized trial

Mediated physical activity interventions can reach large numbers of people at low cost. Programs delivered through the mail that target the stage of motivational readiness have been shown to increase activity. Communication technology (websites and e-mail) might provide a means for delivering similar programs. Randomized trial conducted between August and October 2001. Participants included staff at an Australian university (n=655; mean AGE=43, standard deviation, 10 years). Participants were randomized to either an 8-week, stage-targeted print program (Print) or 8-week, stage-targeted website (Web) program. The main outcome was change in self-reported physical activity.

Assessing flow in physical activity: The Flow State Scale-2 and Dispositional Flow Scale-2

The Flow State Scale-2 (FSS-2) and Dispositional Flow Scale-2 (DFS-2) are presented as two self-report instruments designed to assess flow experiences in physical activity. Item modifications were made to the original versions of these scales in order to improve the measurement of some of the flow dimensions. Confirmatory factor analyses of an item identification and a cross-validation sample demonstrated a good fit of the new scales. There was support for both a 9-first-order factor model and a higher order model with a global flow factor. The item identification sample yielded mean item loadings on the first-order factor of .78 for the FSS-2 and .77 for the DFS-2. Reliability estimates ranged from .80 to .90 for the FSS-2, and .81 to .90 for the DFS-2. In the cross-validation sample, mean item loadings on the first-order factor were .80 for the FSS-2, and .73 for the DFS-2. Reliability estimates ranged between .80 to .92 for the FSS-2 and .78 to .86 for the DFS-2. The scales are presented as ways of assessing flow experienced within a particular event (FSS-2) or the frequency of flow experiences in chosen physical activity in general (DFS-2).

Approximate analytical solutions for porous catalysts with nonuniform activity

Using a novel finite integral transform technique, the problem of diffusion and chemical reaction in a porous catalyst with general activity profile is investigated theoretically. Analytical expressions for the effectiveness factor are obtained for pth order and Michaelis-Menten kinetics. Perturbation methods are employed to provide useful asymptotic solutions for large or small values of Thiele modulus and Biot number.

PACAP stimulates dopamine neuronal activity in the medial basal hypothalamus and inhibits prolactin

In sheep intracerebroventricular injection of PACAP (10 nmol) significantly (P < 0.01) stimulated the levels of the dopamine metabolite DOPAC within the medial basal hypothalamus las measured by in vivo microdialysis) and this effect was temporally correlated with a significant (P < 0.05) suppression in peripheral prolactin concentrations. This result is in accord with the hypothesis that PACAP suppresses prolactin secretion from the anterior pituitary gland by stimulating dopamine release from tuberoinfundibular dopaminergic neurons. (C) 1998 Elsevier Science B.V.

Th2-type CD4(+) cells neither enhance nor suppress antitumor CTL activity in a mouse tumor model

Many cervical cancers express the E7 protein of human papillomavirus 16 as a tumor-specific Ag (TSA). To establish the role of E7-specific T cell help in CD8(+) CTL-mediated tumor regression, C57BL/6J mice were immunized with E7 protein or with a peptide (GF001) comprising a minimal CTL epitope of E7, together with different adjuvants, Immunized mice were challenged with an E7-expressing tumor cell line, EL4.E7. Growth of EL4.E7 was reduced following immunization with E7 and Quil-A (an adjuvant that induced a Th1-type response to E7) or with GF001 and Quil-A, Depletion of CD8(+) cells, but not CD4(+) cells, from an immunized animal abrogated protection, confirming that E7-specific CTL are necessary and sufficient for TSA-specific protection in this model. Immunization with E7 and Algammulin (an alum-based adjuvant) induced a Th2-like response and provided; no tumor protection. To investigate whether a Th2 T helper response to E7 could prevent the development of an E7-specific CTL-mediated protection, mice were simultaneously immunized with E7/Algammulin and GF001/Quil-A or, alternatively, were immunized with GF011/Quil-A 8 wk after immunization with E7/Algammulin, Tumor protection was observed in each case. We conclude that an established Th2 response to a TSA does not prevent the development of TSA-specific tumor protective CTL.

Chronic ethanol treatment leads to increased ornithine decarboxylase activity: Implications for a role of polyamines in ethanol dependence and withdrawal

Recent research has focused on the N-methyl-D-aspartate receptor system as a major site of ethanol action in the brain and specifically on compensatory changes in the expression of the polyamine-sensitive NR2B subunit. Therefore, we examined the effects of chronic ethanol treatment on polyamine homeostasis in the rat brain. Wistar rats were made dependent by ethanol vapor inhalation. This caused a rise in hippocampal ornithine decarboxylase (ODC) activity that was correlated with the appearance of physiological dependence. ODC activity returned to control levels within 3 days of ethanol withdrawal. Enzyme activity also increased in the cerebral cortex, striatum, and cerebellum of the ethanol-dependent rats. The concentration of the polyamines (putrescine, spermidine, and spermine) in the hippocampus was increased in ethanol-dependent rats. Injection of the ODC inhibitor, gamma-difluoromethylornithine (500 mg/kg) at the onset of withdrawal resulted in a significant reduction in the severity of withdrawal behaviors. The level of ODC activity and the severity of withdrawal behaviors were positively correlated. Perturbed polyamine homeostasis may represent an important molecular component in the initiation of ethanol withdrawal behaviors in the ethanol-dependent rat.

Ethanol inhibition of brain ornithine decarboxylase activity in the postnatal rat

The purpose of this study was to determine the relationship between ornithine decarboxylase activity (ODC; a marker for perturbed cell development), the blood alcohol level, and alcohol-induced microencephaly in the developing rat brain after binge treatment with ethanol vapour. By manipulating ethanol flow we were able to adjust vapour concentrations (24-65 mg ethanol/l air) such that an acute exposure of ethanol vapour for 3 h resulted in a range of blood alcohol levels (2.3-5.5 mg/ml). Acute studies showed that ethanol dose-dependently inhibited rat hippocampal and cerebellar ODC activity at PND4-PND10. There was a significant correlation between the blood alcohol level and degree of inhibition at all ages tested. Chronic treatment from PND4 to PND9 caused a significant decrease in both brain to body weight ratio and in hippocampal and cerebellar ODC activities at PND10. These results indicate that ethanol-induced disruption in ODC could play a significant role in ethanol's teratogenic effects during early postnatal development. (C) 1998 Elsevier Science Inc.