Publications

Understanding how neighborhood environments are related to older adults' quality of life (QoL) and physical activity (PA) is important for public health actions on healthy ageing in sub-Saharan Africa. We examined associations of perceived neighborhood environment attributes with QoL among older adults in Nigeria and investigated the moderating effects of PA on these associations. We conducted a cross-sectional study of 353 older adults (mean age = 68.9 ± 9.1 years) selected from 5 high- and low-income communities in Maiduguri, Nigeria. QoL, attributes of the neighborhood environments and PA were self-reported using validated questionnaires. Multi-level models were used to examine the direct associations between neighborhood environment attributes and each of the four domains of QoL (physical health, psychological health, social relationships, and environmental health), as well as the moderating effects of leisure-time and total PA. Seven of nine neighborhood environment features were positively associated with multiple domains of QoL. Residential density, land-use diversity, land-use mix-access, walking infrastructure, traffic safety and 'overall walkability' were positively related to both or either physical health and environmental health QoL among those who are physically active. In contrast, walking infrastructure, traffic safety, and 'overall walkability' were negatively related to psychological health QoL among those not physically active. Our findings suggest being physically active moderates the association of neighborhood environments with QoL among Nigerian older adults. We suggest that designing age-friendly communities and simultaneously promoting PA may be needed to improve QoL and help prepare the Nigerian society for the predicted increase in the older adult population.

CUP2 is a copper-dependent transcriptional activator of the yeast CUP1 metallothionein gene. In the presence of Cu+ and Ag+) ions its DNA-binding domain is thought to fold as a cysteine-coordinated Cu cluster which recognizes the palindromic CUP1 upstream activation sequence (UASc). Using mobility shift, methylation interference, and DNase I and hydroxyl radical footprinting assays, we examined the interaction of wild-type and variant CUP2 proteins produced in Escherichia coli with the UASc. Our results suggest that CUP2 has a complex Cu-coordinated DNA-binding domain containing different parts that function as DNA-binding elements recognizing distinct sequence motifs embedded within the UASc. A single-amino-acid substitution of cysteine 11 with a tyrosine results in decreased Cu binding, apparent inactivation of one of the DNA-binding elements and a dramatic change in the recognition properties of CUP2. This variant protein interacts with only one part of the wild-type site and prefers to bind to a different half-site from the wild-type protein. Although the variant has about 10% of wild-type DNA-binding activity, it appears to be completely incapable of activating transcription.

Leisure-time and transport activity domains are studied most often because they are considered more amenable to intervention, but to date evidence on these domains is limited. The aim of the present study was to examine patterns of socio-demographic correlates of adults' leisure-time and transport physical activity and how these associations varied across 17 cities in 12 countries.

The purpose of this study was to determine the validity and reliability of three of the most commonly used field tests to predict maximum oxygen uptake in children and adolescents. VO

Neighborhood walkability is favorably related to multiple physical health outcomes, but associations with social health are less clear. Present analyses examined how neighborhood walkability was related to neighborhood social health and explored the potential confounding role of neighborhood self-selection.Cross-sectional data were analyzed for 1745 adults, ages 20-66, recruited from two US regions. We created a walkability index around each participant's home (1 km street network buffer) based on residential density, street intersection density, mixed land use, and retail floor area ratio. Neighborhood social health outcomes included reported social interactions with neighbors and sense of community. Two mixed model regressions were conducted for each outcome, with and without adjusting for walkability-related reasons for moving to the neighborhood (self-selection). Covariates included sex, age, socioeconomic status, white/nonwhite race/ethnicity, marital status, and time living in the neighborhood.Neighborhood walkability was positively related to social interactions with neighbors, both without (b = 0.13, p < .001) and with adjustment for self-selection (b = 0.09, p = .008). Neighborhood walkability was positively associated with sense of community, but only before adjusting for self-selection (b = 0.02, p = .009).Neighborhood walkability may promote specific aspects of neighborhood social health, which together are beneficial for physical and mental health. These findings provide additional impetus for enhancing walkability of US communities.

Female adolescents are less active than male peers in certain contexts including the neighborhood. Adolescents' physical activity can be explained by interactions between environmental and psychosocial factors, but few studies have tested such interactions in relation to context-specific behaviors. This study tested interactions between neighborhood environmental and psychosocial factors in relation to adolescents' context-specific physical activity. Data were collected in 2009–11 from 910 adolescents and a parent/guardian residing in the Baltimore/Seattle regions. Measures included adolescent-reported neighborhood leisure-time physical activity (LTPA) and non-neighborhood LTPA, accelerometer-based non-school moderate-to vigorous-physical activity (MVPA), psychosocial factors, and objective and parent-perceived neighborhood environmental factors. Gender-stratified mixed effects linear models tested associations of 6 environmental and 4 psychosocial factors and their interactions in relation to each physical activity outcome. The psychosocial factors had consistent associations with the physical activity outcomes but the environmental correlates were context-specific. Decisional balance (weighing of pros and cons of physical activity) moderated the association between recreation facility density and neighborhood LTPA among females, with a negative association only among those with high decisional balance (pros outweighed cons). Decisional balance also moderated associations of neighborhood walkability with non-school MVPA among females and non-neighborhood LTPA among males, with positive associations only among those with high decisional balance. Results support context-specific ecological models of physical activity. Targeting environmental factors that may promote opportunities for physical activity in specific contexts as well as adolescent decision-making may help promote their physical activity in those contexts, potentially leading to increased overall physical activity.

Stress signals activate both inhibitor of nuclear factor-kappaB kinase (IKKbeta) and c-Jun NH(2)-terminal kinase (JNK). It was shown recently that IKK-dependent nuclear factor kappaB activation results in attenuation of tumor necrosis factor alpha-induced JNK activation. How that negative cross-talk between nuclear factor kappaB and JNK occurs is not well-understood. By using wild-type and Ikkbeta gene knockout (Ikkbeta(-/-)) mouse embryo fibroblasts, we found that IKKbeta deficiency results in prolongation of arsenic-induced JNK activation, which was not due to the decreased expression of GADD45beta or X-linked Inhibitor of Apoptosis (XIAP), as suggested previously for RelA(-/-) cells treated with tumor necrosis factor alpha. This enhanced JNK activation was largely associated with an oxidative stress response as indicated by elevated expression of heme oxygenase-1 and the accumulation of H(2)O(2) in Ikkbeta(-/-) cells. Expression profiling experiments revealed an increased expression of p450 family CYP1B1 mRNA in Ikkbeta(-/-) cells compared with wild-type cells. Inhibition of CYP1B1 reduced both oxidative stress and arsenic-stimulated JNK activation. Thus, increased CYP1B1 expression is central to and seems to be responsible for sensitizing Ikkbeta(-/-) cells to stress-induced JNK activation.

In resting cells, c-Jun is phosphorylated on five sites. Three of these sites reside next to its DNA binding domain and negatively regulate DNA binding. In response to expression of oncogenic Ha-Ras, phosphorylation of these sites decreases, while phosphorylation of two other sites within c-Jun's activation domain is greatly enhanced. Phosphorylation of these residues, serines 63 and 73, stimulates the transactivation function of c-Jun and is required for oncogenic cooperation with Ha-Ras. We now show that the same changes in c-Jun phosphorylation are elicited by a variety of transforming oncoproteins with distinct biochemical activities. These oncoproteins, v-Sis, v-Src, Ha-Ras, and Raf-1, participate in a signal transduction pathway that leads to increased phosphorylation of serines 63 and 73 on c-Jun. While oncogenic Ha-Ras is a constitutive stimulator of c-Jun activity and phosphorylation, the normal c-Ha-Ras protein is a serum-dependent modulator of c-Jun's activity. c-Jun is therefore a downstream target for a phosphorylation cascade involved in cell proliferation and transformation.