Publications

Recent research highlights the potential value of differentiating between categories of physical activity intensities as predictors of health and well-being. This study sought to assess reliability and concurrent validity of sedentary (ie, 1 METs), low-light (ie, >1 and ≤2 METs; eg, playing cards), high-light (ie, >2 and <3 METs; eg, light walking), moderate-to-vigorous physical activity (MVPA, ≥3 METs), and "total activity" (≥2 METs) from the CHAMPS survey. Further, this study explored over-reporting and double-reporting.

Objective Children consume about one third of their daily energy at school, mostly from cafeteria food and bag lunches. Students also shop at studentrun stores that generate revenue for extracurricular activities; yet the nutritional value of snacks sold at student stores has not been documented to our knowledge. Design Cross-sectional study of foods sold at student stores in middle schools. Subjects/setting Twentyfour San Diego County (Calif) public middle schools, grades 6 through 8 (age 11 to 13), from 9 school districts. The schools represent a diversity of ethnic groups and socioeconomic levels. Statistical analyses performed Descriptive statistics, Pearson product moment correlations, analysis of variance. Results Snacks averaged 8.7g fat and 23.0g sugar. Overall, 88.5% of store inventory was high in fat and/or high in sugar. Sugar candy accounted for one third of store sales. Chocolate candy was highest in fat content: 15.7g. Fourteen of the 24 schools had stores that sold food and were run by student organizations. Stores were open daily for about 90minutes; half sold food during lunch. Conclusions Adolescents need opportunities to supplement main meals; however, student stores in middle schools sell primarily high-fat, high-sugar snacks. Key intervention possibilities include limiting sales of chocolate candy and substituting low-fat varieties of cakes, cookies, chips, and crackers. Competition with cafeterias for sales at lunchtime should be addressed. J Am Diet Assoc. 2000; 100:319 322.

Background The Preventive Cardiology Center compared two intensities of behavior modification for cardiovascular disease (CVD) risk factors in persons at risk and their families. Characteristics of drop-outs both before and after intervention were compared with subjects who completed the 6-month trial.

NOD2, a NOD-like receptor (NLR), is an intracellular sensor of bacterial muramyl dipeptide (MDP) that was suggested to promote secretion of the proinflammatory cytokine IL-1beta. Yet, the molecular mechanism by which NOD2 can stimulate IL-1beta secretion, and its biological significance were heretofore unknown. We found that NOD2 through its N-terminal caspase recruitment domain directly binds and activates caspase-1 to trigger IL-1beta processing and secretion in MDP-stimulated macrophages, whereas the C-terminal leucine-rich repeats of NOD2 prevent caspase-1 activation in nonstimulated cells. MDP challenge induces the association of NOD2 with another NLR protein, NALP1, and gel filtration analysis revealed the formation of a complex consisting of NOD2, NALP1, and caspase-1. Importantly, Bacillus anthracis infection induces IL-1beta secretion in a manner that depended on caspase-1 and NOD2. In vitro, Anthrax lethal toxin strongly potentiated IL-1beta secretion, and that response was NOD2 and caspase-1-dependent. Thus, NOD2 plays a key role in the B. anthracis-induced inflammatory response by being a critical mediator of IL-1beta secretion.

The nuclear phosphoprotein c-Jun, encoded by the proto-oncogene c-jun, is a major component of the AP-1 complex. A potent transcriptional regulator, c-jun is also able to transform normal rat embryo cells in cooperation with an activated c-Ha-ras gene. By deletion analysis, we identified the regions of c-Jun encoding transformation and transactivation functions. Our studies indicate that there is a direct correlation between the ability of the c-Jun protein to activate transcription and cotransform rat embryo cells. The regions involved in these functions include the conserved leucine zipper/DNA binding domain and an effector domain near its N terminus. This N-terminal region spans amino acids 61 to 146 of the c-Jun protein and is highly conserved among all Jun family members. These results support the hypothesis that c-Jun transforms cells by stimulating the expression of transformation-mediating genes.

Community-based interventions are needed to reduce the burden of childhood obesity.

The gene copy number at the CUP1 locus and the resistance level to external copper was directly correlated in five wild-type commercial Saccharomyces strains. An increased copy number of the CUP1 gene leads to increased accumulation of chelatin mRNA, which codes for a low-molecular-weight, copper-binding protein. The enhanced production of this rapidly inducible protein mediates resistance of the cell to copper. Industrial yeasts exhibit homologies to the amplified copper resistance repeat unit found in laboratory strains. However, the extent of tandem iteration is strain dependent, and the repetitious unit is either 1.7 or 1.5 kilobases in length compared with the 2.0-kilobase unit in laboratory strains. Strain 522 (Montrachet) contains two chromosome VIII segments distinguishable by their numbers of repeat units (2 and 11) and the size of the units (1.5 and 1.7 kilobases). Distillers yeast 513 carries a 1.5-kilobase repeat unit on each homologous chromosome, although they contain nine and five iterations, respectively.

In this review, our first purpose is to provide an overview of existing physical activity intervention research, focusing on subpopulations and intervention modalities. Our reviews within each area are not exhaustive or quantitative, as each area has been reviewed in more depth in numerous other reports. Instead, our goal is to provide a single document that provides a qualitative overview of intervention research that emphasizes selected topics of particular importance for improving the population-wide impact of interventions. Therefore, in synthesizing this vast literature, we begin with existing reviews of physical activity research in each area and incorporate in our discussions recent reports of well-designed individual physical activity intervention studies that expand the existing research base and/or target new areas of research. Our second purpose is to offer new ideas and recommendations to improve the state of the science within each area and, where possible, to propose ideas to help bridge the gaps between these existing categories of research.

1155 The purpose of this paper is to investigate the relationship between a self-report and proxy report of physical activity (PA) in adolescent children in grades 7-12. The subjects were students enrolled in the public school system in Amherst, MA. On separate occasions not more than one month apart, a parent and child filled out similar questionnaires pertaining to the child's physical activity. Spearman correlations between the responses from each questionnaire were calculated to examine the association between child and parent estimates of PA. A total of 531 children with a mean age of 14 ± 1.6 had complete information on both questionnaires. The sample was 45.4% male, 77.02% white, and the mother was the proxy for 76.65% of the children. The table presents the Spearman correlations between responses given by the child and the child's parent.TableParental proxy reports of physical activity are significantly associated with the child's estimate of this activity; r2 = 8 - 49%. This association increased as intensity increased.

Previous studies have investigated the potential role of neighborhood walkability in reducing sedentary behavior. However, the majority of this research has been conducted in adults and Western developed countries. The purpose of the present study was to examine associations of neighborhood environmental attributes with sedentary time among older adults in Nigeria. Data from 353 randomly-selected community-dwelling older adults (60 years and above) in Maiduguri, Nigeria were analyzed. Perceived attributes of neighborhood environments and self-reported sedentary time were assessed using Nigerian-validated and reliable measures. Outcomes were weekly minutes of total sedentary time, minutes of sitting on a typical weekday, and minutes of sitting on a typical weekend day. In multivariate regression analyses, higher walkability index, proximity to destinations, access to services, traffic safety, and safety from crime were associated with less total sedentary time and sedentary time on both a weekday and a weekend day. Moderation analysis showed that only in men was higher walking infrastructure and safety found to be associated with less sedentary time, and higher street connectivity was associated with more sedentary time. The findings suggest that improving neighborhood walkability may be a mechanism for reducing sedentary time among older adults in Nigeria.

Validity, reliability, and calibration of the Tritrac accelerometer as a measure of physical activity. Med. Sci. Sports Exerc., Vol. 31, No. 6, pp. 908-912, 1999. Purpose: The purposes of this study were to assess the validity and reliability of the Tritrac R3D accelerometer during treadmill walking and running and then to calibrate the instrument. Methods: The Tritrac was assessed on 60 young adults (23.4 ± 2.9 yr) during treadmill walking and running at 3.2, 6.4, and 9.7 km·h−1. The calibration was carried out by identifying ranges of Tritrac raw data (vector magnitude) values corresponding to light (2-3.9 MET), moderate (4-7 MET), and vigorous (>7 MET) physical activity. Energy expenditure (EE), measured by indirect calorimetry, served as the criterion measure. Results: Interinstrument intraclass reliability coefficients for Tritracs worn on the right and left hip ranged from 0.73-0.87, while intersession coefficients demonstrated high reliability for all speeds (R = 0.87-0.92). Paired t-tests comparing mean accelerometer counts at 6.4 km·h−1, 0% grade (2647 ± 456), and 6.4 km·h−1, 5% grade (2635 ± 435) demonstrated no significant difference (P > 0.05). Mean differences between EE measured by indirect calorimetry and that estimated by the Tritrac ranged from 0.0082 kcal·kg−1·min−1 at 3.2 km·h−1 to 0.0320 kcal·kg−1·min−1 at 9.7 km·h−1, with the Tritrac consistently overestimating EE during horizontal treadmill walking. The relationship between vector magnitude and EE across all speeds was highly linear (R2 = 0.90, SEE = 0.014 kcal·kg−1·min−1), with little overlap between light, moderate, and vigorous categories. The mean vector magnitudes at 2, 4, and 7 MET were 650, 1772, and 3455, respectively. Conclusions: These data indicate that the Tritrac is highly reliable from day to day and is sensitive to changes in speed but not grade. Furthermore, the Tritrac accurately distinguishes various intensities of walking and jogging on level ground. With limitations, these cut-points can be used to categorize light, moderate, and vigorous physical activity and to estimate EE.