Adolescent Psychological and Social Predictors of Young Adult Smoking Acquisition and Cessation: A 10-Year Longitudinal Study

Item does not contain fulltextObjective: A 10-year follow-up study to test the extent to which theory-based adolescent psychological and social factors directly predict and moderate the prediction of young adult smoking acquisition and cessation. Design: A prospective community-based sample. A total of 2,970 adolescents participated in the large Washington State Hutchinson Smoking Prevention Project (HSPP) longitudinal cohort. As predictors, psychological factors (i.e., parentnoncompliance, friendcompliance, rebelliousness, achievement motivation, and thrill seeking) and social environmental factors (i.e., parent's and friend's smoking) were measured when adolescents were 17-18 years old. Main Outcome Measures: As main outcome measures, smoking acquisition and cessation were assessed both at ages 18 and 28. Results: Psychological and social factors predicted 3% to 7% probability (p < .05) of smoking acquisition and a nonsignificant to 24% probability (p < .05) of smoking continuation (not quitting) in young adulthood. Both friendcompliance and rebelliousness were more powerful predictors of young adult-smoking continuation than of smoking acquisition. Conclusion: First evidence that parent noncompliance, friend compliance, and a lack of achievement motivation predict smoking acquisition and (with the exception of parent noncompliance) smoking continuation in young adulthood. Including these psychological factors in future interventions designed to promote young adult smoking cessation may be useful

Seed germination and dormancy traits of forbs and shrubs important for restoration of North American dryland ecosystems

© 2018 German Society for Plant Sciences and The Royal Botanical Society of the Netherlands In degraded dryland systems, native plant community re-establishment following disturbance is almost exclusively carried out using seeds, but these efforts commonly fail. Much of this failure can be attributed to the limited understanding of seed dormancy and germination traits. We undertook a systematic classification of seed dormancy of 26 species of annual and perennial forbs and shrubs that represent key, dominant genera used in restoration of the Great Basin ecosystem in the western United States. We examined germination across a wide thermal profile to depict species-specific characteristics and assessed the potential of gibberellic acid (GA3) and karrikinolide (KAR1) to expand the thermal germination envelope of fresh seeds. Of the tested species, 81% produce seeds that are dormant at maturity. The largest proportion (62%) exhibited physiological (PD), followed by physical (PY, 8%), combinational (PY + PD, 8%) and morphophysiological (MPD, 4%) dormancy classes. The effects of chemical stimulants were temperature- and species-mediated. In general, mean germination across the thermal profile was improved by GA3 and KAR1 for 11 and five species, respectively. We detected a strong germination response to temperature in freshly collected seeds of 20 species. Temperatures below 10 °C limited the germination of all except Agoseris heterophylla, suggesting that in their dormant state, the majority of these species are thermally restricted. Our findings demonstrate the utility of dormancy classification as a foundation for understanding the critical regenerative traits in these ecologically important species and highlight its importance in restoration planning

&alpha;-Melanocyte stimulating hormone promotes muscle glucose uptake via melanocortin 5 receptors.

OBJECTIVE: Central melanocortin pathways are well-established regulators of energy balance. However, scant data exist about the role of systemic melanocortin peptides. We set out to determine if peripheral &alpha;-melanocyte stimulating hormone (&alpha;-MSH) plays a role in glucose homeostasis and tested the hypothesis that the pituitary is able to sense a physiological increase in circulating glucose and responds by secreting &alpha;-MSH. METHODS: We established glucose-stimulated &alpha;-MSH secretion using humans, non-human primates, and mouse models. Continuous &alpha;-MSH infusions were performed during glucose tolerance tests and hyperinsulinemic-euglycemic clamps to evaluate the systemic effect of &alpha;-MSH in glucose regulation. Complementary ex&nbsp;vivo and in&nbsp;vitro techniques were employed to delineate the direct action of &alpha;-MSH via the melanocortin 5 receptor (MC5R)-PKA axis in skeletal muscles. Combined treatment of non-selective/selective phosphodiesterase inhibitor and &alpha;-MSH was adopted to restore glucose tolerance in obese mice. RESULTS: Here we demonstrate that pituitary secretion of &alpha;-MSH is increased by glucose. Peripheral &alpha;-MSH increases temperature in skeletal muscles, acts directly on soleus and gastrocnemius muscles to significantly increase glucose uptake, and enhances whole-body glucose clearance via the activation of muscle MC5R and protein kinase A. These actions are absent in obese mice, accompanied by a blunting of &alpha;-MSH-induced cAMP levels in skeletal muscles of obese mice. Both selective and non-selective phosphodiesterase inhibition restores &alpha;-MSH induced skeletal muscle glucose uptake and improves glucose disposal in obese mice. CONCLUSION: These data describe a novel endocrine circuit that modulates glucose homeostasis by pituitary &alpha;-MSH, which increases muscle glucose uptake and thermogenesis through the activation of a MC5R-PKA-pathway, which is disrupted in obesity