Publications

Few studies have explored how relationships of perceived environment and physical activity vary across different activity domains and populations. This question was explored in five physical activity intervention trials funded by the National Institutes of Health Behavior Change Consortium.Observational.San Francisco peninsula, California (N = 94); Eugene, Oregon (N = 122); Atlanta, Georgia (N = 256); Kingston, Rhode Island (N = 109); Memphis, Tennessee (N = 64).Ethnically diverse community adults ages 18 to 85 years.The Neighborhood Environment Walkability Scale and CHAMPS physical activity questionnaire. Response rate among those invited to complete these measures was 90%.Cross-sectional pooled signal detection analysis indicated that people who reported living in neighborhoods with more attractive scenery and ease of walking were more likely to meet national physical activity recommendations (67%) compared with those without these neighborhood attributes (36%; chi2 = 13.04, p = .0003). Within-site multiple regression identified two additional variables--seeing others when walking and encountering loose dogs that make it difficult to walk--as correlates across multiple sites and activity domains (i.e., minutes of weekly moderate or more vigorous activity, walking for errands, walking leisurely) (incremental R2 = 2.0-7.5; p < .05). Analyses of covariance suggested that traffic safety might be particularly important in facilitating or impeding physical activity in response to a formal intervention (for traffic-arm assignment interactions, F = 3.8-7.0, p < or = .05).Relationships between perceived environments and physical activity may differ depending upon population groups and activity domains and merit investigation by using stronger prospective designs.

Retinoids such as retinoic acid (RA) are potent anti-arthritic and anti-neoplastic agents. We investigated the mechanism by which RA inhibits induction of collagenase gene transcription by inflammatory mediators, tumor promoters, and proto-oncogenes. We found that the RA receptors (RARs) are potent inhibitors of AP-1 activity generated either by cJun homodimers or cJun/cFos heterodimers. In addition, both cJun and cFos can inhibit RAR activity. In vitro experiments suggested that this inhibition is due to an interaction between RAR and AP-1 proteins that results in mutual loss of DNA-binding activity. The RARs need not bind to the AP-1 site, neither does AP-1 bind to RA response elements. An understanding of this antagonism between the RAR and AP-1 might help to elucidate the anti-neoplastic and anti-arthritic effects of RA as well as its effects on cell differentiation and proliferation.

Active transportation (AT) is widely viewed as an important target for increasing participation in aerobic physical activity and improving health, while simultaneously addressing pollution and climate change through reductions in motor vehicular emissions. In recent years, progress in increasing AT has stalled in some countries and, furthermore, the coronavirus (COVID-19) pandemic has created new AT opportunities while also exposing the barriers and health inequities related to AT for some populations. This paper describes the results of the December 2019 Conference on Health and Active Transportation (CHAT) which brought together leaders from the transportation and health disciplines. Attendees charted a course for the future around three themes: Reflecting on Innovative Practices, Building Strategic Institutional Relationships, and Identifying Research Needs and Opportunities. This paper focuses on conclusions of the Research Needs and Opportunities theme. We present a conceptual model derived from the conference sessions that considers how economic and systems analysis, evaluation of emerging technologies and policies, efforts to address inclusivity, disparities and equity along with renewed attention to messaging and communication could contribute to overcoming barriers to development and use of AT infrastructure. Specific research gaps concerning these themes are presented. We further discuss the relevance of these themes considering the pandemic. Renewed efforts at research, dissemination and implementation are needed to achieve the potential health and environmental benefits of AT and to preserve positive changes associated with the pandemic while mitigating negative ones.

Few studies have explored barriers to physical activity in parks and streets among children, adolescents, and their parents. The purpose of this article is to evaluate the psychometric properties of a new survey of barriers to physical activity in neighborhood parks and streets. Adolescents and parents of children and adolescents completed surveys twice. Two barrier subscales (environment and safety) emerged that applied to both locations and all participant groups. Results generally supported acceptable, internal consistency as well as construct validity, but test-retest reliabilities were lower than desired. These scales may be used to improve understanding of perceptions of barriers to physical activity in neighborhood parks and streets, but further development is needed.

No abstract is provided for this article.

Matrix metalloproteinase-1 (MMP-1) is a collagenase that is highly active in extracellular matrix and vascular remodeling, angiogenesis, and tumor progression. Vascular endothelial growth factor receptor-2 (VEGFR2), the main receptor for VEGF-A, is expressed on endothelial cells and promotes cell survival, proliferation, and other functions. Although MMP-1 and VEGFR2 co-exist in many normal and pathophysiological conditions, the effect of MMP-1 on cellular VEGFR2 that can promote the above processes is unknown. In this study we test the hypothesis that stimulation of endothelial cells with MMP-1 increases their levels of VEGFR2. The increased VEGFR2 is then available to bind VEGF-A, resulting in increased response. Indeed we found that endothelial cells incubated with active MMP-1 had higher mRNA and protein levels of VEGFR2. Furthermore, VEGF-A-dependent phosphorylation of intracellular signaling molecules and endothelial proliferation were elevated after MMP-1 treatment. MMP-1 caused activation of the nuclear factor-κB (NF-κB) pathway (p65/RelA) in endothelial cells, and this response was dependent upon activation of protease activated receptor-1 (PAR-1). Chromatin immunoprecipitation was used to confirm NF-κB-mediated active transcription of the VEGFR2 (KDR) gene. Elevation in VEGFR2 after MMP-1 stimulation was inhibited by PAR-1 knockdown and NF-κB specific inhibition. We conclude that MMP-1 promotes VEGFR2 expression and proliferation of endothelial cells through stimulation of PAR-1 and activation of NF-κB. These results suggest a mechanism by which MMP-1 may prime or sensitize endothelial cell functions.

Objectives To investigate relations of walking, bicycling and vehicle time to neighborhood walkability and total physical activity in youth. Methods Participants (N=690) were from 380 census block groups of high/low walkability and income in two US regions. Home neighborhood residential density, intersection density, retail density, entertainment density and walkability were derived using GIS. Minutes/day of walking, bicycling and vehicle time were derived from processing algorithms applied to GPS. Accelerometers estimated total daily moderate-to-vigorous physical activity (MVPA). Models were adjusted for nesting of days (N=2987) within participants within block groups. Results Walking occurred on 33%, active travel on 43%, and vehicle time on 91% of the days observed. Intersection density and neighborhood walkability were positively related to walking and bicycling and negatively related to vehicle time. Residential density was positively related to walking. Conclusions Increasing walking in youth could be effective in increasing total physical activity. Built environment findings suggest potential for increasing walking in youth through improving neighborhood walkability.

Variants of NOD2, an intracellular sensor of bacteria-derived muramyl dipeptide (MDP), increase susceptibility to Crohn's disease (CD). These variants are thought to be defective in activation of nuclear factor kappaB (NF-kappaB) and antibacterial defenses, but CD clinical specimens display elevated NF-kappaB activity. To illuminate the pathophysiological function of NOD2, we introduced such a variant to the mouse Nod2 locus. Mutant mice exhibited elevated NF-kappaB activation in response to MDP and more efficient processing and secretion of the cytokine interleukin-1beta (IL-1beta). These effects are linked to increased susceptibility to bacterial-induced intestinal inflammation and identify NOD2 as a positive regulator of NF-kappaB activation and IL-1beta secretion.