Publications

Monitoring physical activity with electronic devices that use non-volatile memory is an attractive technology as it allows the user to examine patterns in physical activity as well as total activity. A new device that may be used for such purposes is the CSA accelerometer (model #7164). The device is small(5 × 5 × 1.5 cm, 70gm) which makes it particularly useful for evaluating activity in children. The aim of this study was to examine the relationship between measured METS and the 7164 accelerometer counts/min for children (age range = 6-17 yrs.). Eighty subjects (41F, 39M) completed 3, 5min treadmill conditions (2 walking and 1 jogging). CSA counts and respiratory gas exchange measures were monitored min-by-min with average of min 4 and 5 used for analysis. 50 subjects (23F, 27M) were randomly selected as the development group and 30 subjects (18F, 12M) served as the validation group. Regression analysis was used to select the significant predictors of METS: METS = 5.6832+ 0.00093(cts/min) - 0.2613(age in yrs) (R2 = 0.83). Cross-validation results (n=30) revealed no significant difference between actual and predicted METS. Pearson r = 0.86 between actual and predicted METS (SEE = ± 1.29 METS). In conclusion, these results indicate that accelerometer counts can be used to estimate different intensities of physical activity in children.

Youth advocacy can be used for physical activity promotion and obesity prevention. Advocacy is a promising community-based intervention that has potential for environmental, social, and individual changes but has not been documented in a systematic, theory-driven way. PURPOSE: To test the factor structure of a newly developed youth advocacy measure and assess youth pre-post changes on physical activity. METHODS: Based on a model of youth advocacy, scales were developed to assess mediators, intervention processes, and proximal outcomes of youth advocacy for obesity prevention. Youth (baseline n=136) completed surveys before and after advocacy. With baseline data, we created subscales using confirmatory factor analysis. We then assessed youth changes on behavioral and attitudinal subscales including physical activity, before and after completing advocacy projects. RESULTS: Examples of advocacy groups’ targets for change were fixing broken or non-existent sidewalks around a school or in a neighborhood, removing litter and graffiti in local parks, and installing crosswalks and lighting outside a recreation center for improved active transportation. Sports/Physical Activity Enjoyment, Active Transportation, and Meeting Physical Activity Recommendations emerged as distinct factors from the survey that had acceptable factor loadings and intra-item correlations. After advocacy participation, Meeting Physical Activity Recommendations increased significantly from an average of 3.62 (SD: 1.87) to 4.0 (SD: 1.57) days per week, a 10.5% change from baseline (paired t(91)=2.28, p<.05). The other two physical activity-related subscales did not change significantly as a result of advocacy. CONCLUSION: The present study provides preliminary evidence of youth increases in physical activity following participation in an obesity prevention advocacy program. These positive initial finding should be replicated in larger samples. Youth advocacy can have meaningful impacts on and their communities by creating environmental changes that can make physical activity more accessible.

Transcription factor, nuclear factor kappaB (NF-kappaB), is required for osteoclast formation in vivo and mice lacking both of the NF-kappaB p50 and p52 proteins are osteopetrotic. Here we address the relative roles of the two catalytic subunits of the IkappaB kinase (IKK) complex that mediate NF-kappaB activation, IKKalpha and IKKbeta, in osteoclast formation and inflammation-induced bone loss. Our findings point out the importance of the IKKbeta subunit as a transducer of signals from receptor activator of NF-kappaB (RANK) to NF-kappaB. Although IKKalpha is required for RANK ligand-induced osteoclast formation in vitro, it is not needed in vivo. However, IKKbeta is required for osteoclastogenesis in vitro and in vivo. IKKbeta also protects osteoclasts and their progenitors from tumor necrosis factor alpha-induced apoptosis, and its loss in hematopoietic cells prevents inflammation-induced bone loss.

Background: Many American adults remain sedentary despite many known health benefits. Research on the determinants of physical activity have indicated that social support is one of the strongest correlates, but little is known about this relation in important subgroups of middle and older-aged women. Objective: The purpose of this study was to assess the association of physical activity-related social support on several measures of physical activity in a national sample of minority women. A unique aspect of these measures is the inclusion of vigorous household tasks and occupational physical activities. Methods: The US Women's Determinants Study was conducted in 1996–1997. The survey was a modified-random sample, telephone survey of 2912 Black, Hispanic, American Indian/Alaskan Native, and White women age 40 and older. A composite score of physical activity social support (PASS) was analyzed as the independent variable in logistic regression analyses. Four measures of physical activity levels served as the dependent variables. A separate analysis was done to distinguish PASS from friends versus PASS from relatives. The potential confounding effect of race/ethnicity, marital status, age, income and education were evaluated and adjusted in the models. Results: Hispanic women were more likely to have high PASS scores than the other racial/ethnic groups. Odds ratios indicate that subjects with high levels of PASS were significantly less likely to be sedentary than those with low support, even after adjusting for race/ethnicity. While there were significant associations among levels of social support and physical activity, this was not true for the measure of “regular exercise.” There was no significant difference between the contribution of “friend” support versus “family” support on all four measures on physical activity. Discussion: Based on our results, enhancing social support may be an important aspect of interventions aimed at increasing physical activity in a population of sedentary women of various racial/ethnic backgrounds. Also, “regular exercisers” in this population appear to be less reliant social support to maintain their behavior.

52 The purpose of this study was to examine weekly physical activity levels and patterns in college men and women using the Tritrac R3D accelerometer. Thirty men and 40 women (age 24.6 ± 1.9 yr, mean ± SD) were recruited from a health promotion study at a large Southern California urban university. The Tritrac was placed inside a pouch and secured to the subject's right hip with a waist belt. Subjects were instructed to wear the Tritrac during their waking hours for 7 days. Total time spent in light (2-2.9 METs), moderate (3-5.9 METs), and vigorous (≥6 METs) activity over 7 days was 358.1±172.7, 162.7±88.8, and 23.5±50.9 minutes, respectively. The mean number of 20-minute bouts of vigorous exercise per week was 0.39±1.07, while the mean number of 5-minute bouts of vigorous exercise was 0.99±1.90. These data indicate that college students are barely meeting the CDC guideline for moderate physical activity (≥150 min/wk), and are not meeting the ACSM guideline for fitness. Most of their day appears to be spent engaging in physical activity less than 3 METs.

HomeCirculationVol. 107, No. 4American Heart Association Guide for Improving Cardiovascular Health at the Community Level

Niche signals maintain stem cells in a prolonged quiescence or transiently activate them for proper regeneration¹. Altering balanced niche signalling can lead to regenerative disorders. Melanocytic skin nevi in human often display excessive hair growth, suggesting hair stem cell hyperactivity. Here, using genetic mouse models of nevi^2,3, we show that dermal clusters of senescent melanocytes drive epithelial hair stem cells to exit quiescence and change their transcriptome and composition, potently enhancing hair renewal. Nevus melanocytes activate a distinct secretome, enriched for signalling factors. Osteopontin, the leading nevus signalling factor, is both necessary and sufficient to induce hair growth. Injection of osteopontin or its genetic overexpression is sufficient to induce robust hair growth in mice, whereas germline and conditional deletions of either osteopontin or CD44, its cognate receptor on epithelial hair cells, rescue enhanced hair growth induced by dermal nevus melanocytes. Osteopontin is overexpressed in human hairy nevi, and it stimulates new growth of human hair follicles. Although broad accumulation of senescent cells, such as upon ageing or genotoxic stress, is detrimental for the regenerative capacity of tissue⁴, we show that signalling by senescent cell clusters can potently enhance the activity of adjacent intact stem cells and stimulate tissue renewal. This finding identifies senescent cells and their secretome as an attractive therapeutic target in regenerative disorders.

No abstract is provided for this article.

Our findings show that the IκB kinase–NF-κB signaling pathway is important for both promoting treatment resistance and preventing host toxicity in cancer chemotherapy; however, the two functions are exerted by distinct cell type–specific mechanisms and can therefore be selectively targeted to achieve an improved therapeutic outcome.