Urine release in freely moving catheterised lobsters (Homarus americanus) with reference to feeding and social activities. (1/3932)

Previous studies suggest that urine-borne pheromones play an important role in lobster agonistic and sexual behaviour. This paper investigates the pattern of urine release in catheterised, but otherwise freely moving, adult lobsters with respect to feeding, social and non-social activities. Lobsters on average released 4.1 ml (1 % of body mass) of urine over a 12 h period; this more than doubled to 10.6 ml over the 12 h period after feeding. Hourly monitoring revealed that most urine was released in the first hour after feeding (2.84 ml). With the exception of the first hours after feeding, urine release was intermittent, with pauses lasting up to 17 h. The probability of urine release per hour in unfed lobsters was 0.34 (median); this value increased during agonistic interactions elicited by the introduction of a conspecific (median 0. 63) and during activity initiated by non-social disturbance (median 0.56). Mean urine volume during output hours in unfed lobsters amounted to 1.09 ml h-1. This volume was significantly increased by the presence of a conspecific (1.88 ml h-1) and decreased during activity initiated by non-social disturbances (0.56 ml h-1). No sex-specific differences in urine release were found. The data demonstrate that lobsters control their urine release in a manner dependent on behavioural context. This supports recent findings suggesting the use of urine for chemical signalling in agonistic interactions.  (+info)

Characterization of socio-psychological stress-induced antinociception in the formalin test in mice. (2/3932)

The antinociceptive effect induced by exposure to socio-psychological (PSY) stress using a communication box was assessed by the formalin test in mice, compared with those by exposure to footshock (FS) stress and forced swimming (SW) stress. After the termination of stress exposure, whereas exposure to FS- and SW-stress resulted in the attenuation of the formalin-induced biphasic pain response over 15 min, no appreciable antinociceptive effect was found in the case of PSY stress. When exposure to PSY stress was started during the period of early or late phase of pain after the formalin injection, the antinociceptive effect was maintained for 5-15 min; however, further exposure to PSY stress was not effective for producing antinociception. In the tail-pinch test, likewise, exposure to PSY stress longer than 5 min rather decreased the intensity of antinociception. We conclude that PSY stress in this tonic pain paradigm produces antinociception, but further continuous exposure to the emotional stress caused mice to become recuperative even in such a fear-inducing situation.  (+info)

Psychosocial factors related to adolescent smoking: a critical review of the literature. (3/3932)

OBJECTIVE: To extend the analysis of psychosocial risk factors for smoking presented in the United States surgeon general's 1994 report on smoking and health, and to propose a theoretical frame of reference for understanding the development of smoking. DATA SOURCES: General Science Index, Medline, PsycLIT, Sociofile, Sociological Abstracts, and Smoking and Health. Holdings of the Addiction Research Foundation of Ontario Library as well as the authors' personal files. STUDY SELECTION: Reviewed literature focused on studies that examined the association of sociodemographic, environmental, behavioural, and personal variables with smoking. DATA SYNTHESIS: Adolescent smoking was associated with age, ethnicity, family structure, parental socioeconomic status, personal income, parental smoking, parental attitudes, sibling smoking, peer smoking, peer attitudes and norms, family environment, attachment to family and friends, school factors, risk behaviours, lifestyle, stress, depression/distress, self-esteem, attitudes, and health concerns. It is unclear whether adolescent smoking is related to other psychosocial variables. CONCLUSIONS: Attempts should be made to use common definitions of outcome and predictor variables. Analyses should include multivariate and bivariate models, with some attempt in the multivariate models to test specific hypotheses. Future research should be theory driven and consider the range of possible factors, such as social, personal, economic, environmental, biological, and physiological influences, that may influence smoking behaviour. The apparent inconsistencies in relationships between parental socioeconomic status and adolescent disposable income need to be resolved as does the underlying constructs for which socioeconomic status is a proxy.  (+info)

The urban environment, poverty and health in developing countries. (4/3932)

The process of urbanization could be described as one of the major global environmental changes directly affecting human health today. Populations particularly affected are in developing countries where rapid urban growth has been accompanied by massive urban poverty. Urban environmental health impacts, particularly the impact on adults of an environment of poverty, are still poorly understood. Definitions of the urban environment tend to be physical, excluding the complex ramifications of a social setting of disadvantage. This paper provides a brief overview of existing knowledge on the links between environment, poverty and health in urban areas of developing countries, with an emphasis on the policy implications implied by research on health differential between groups within cities. The paper argues that urban poverty and inequalities in conditions between groups within cities present a central crisis confronting urban policy in terms of human health and quality of life. The paper suggests that definitions of the urban environment tend to consider only the physical, and not the social complexity of the urban setting. The review concludes that the scale and the complexity of the urban crisis in developing countries demands a real commitment to re-thinking the management of cities to address multiple deprivation. The paper suggests that this challenges urban professionals who continue to act with a bias towards unintegrated single sector solutions despite claims to the contrary.  (+info)

Is long-term maintenance of health-related physical activity possible? An analysis of concepts and evidence. (5/3932)

The phenomenon of maintenance of health-related physical activity is explored through an analysis of the underlying concepts and of the existing empirical evidence. The following targets were used for the analysis: (1) the concept of health-related physical activity, (2) the concept of maintenance, (3) common manifestations of maintenance in everyday living, (4) the promotional and behavioral characteristics of health-related physical activity, (5) the known determinants of free-living physical activity, and (6) intervention trials on physical activity in free-living groups. The analyses revealed the inherent resistance to adoption and maintenance of physical activity, particularly that of high-intensity and program-centered activities, the persistence, however, of many simple everyday routines and habits, the multiple determinants discovered for free-living physical activity and a few empirical demonstrations of the successful promotion of the maintenance of physical activity over a year or two. The promotion of the maintenance of health-related physical activity seems thus a distinct possibility provided that (1) the promotional situation is analyzed thoroughly, (2) the activity is chosen carefully with an emphasis on moderation in intensity and integration into the participant's life-style, (3) multiple promotional contacts are used, and (4) support from the participant's social and physical environment is provided. There is a need for more research on the maintenance of health-related physical activity using the stages of change models, behavior modification principles, self-control concepts, the concept of intrinsic motivation and the Relapse model. The method of analysis used here could apply to other health-related behaviors as well.  (+info)

School and community influences on adolescent alcohol and drug use. (6/3932)

Social environment risk factors present in schools and communities have not been thoroughly investigated. This study cross-sectionally examined the social environments of schools and communities, and their influence on adolescent alcohol and drug use. Survey responses of eighth grade students (N = 2309), a random half of their parents (n = 943), community leaders (n = 118), school principals (n = 30), school counselors (n = 30) and chemical health providers (n = 14) were pooled to create indices of social environmental norms, role models, social support and opportunities for non-use of alcohol. Each index was examined for its association with prevalences from 30 schools of alcohol use onset, last-month alcohol use, heavy alcohol use and last-year marijuana use in univariate and stepwise regression analyses. Increases in the levels of norms, role models and opportunities for non-use predicted decreases in alcohol use prevalences. The explanatory power of the examined constructs in multivariate analyses was acceptably high (R2: 38-53%). These findings further support the notion that community-wide efforts need to be launched to affect changes in the normative, role model and opportunity structures of adolescents' social environments in order to curb adolescent alcohol and drug use.  (+info)

Psychosocial correlates of health compromising behaviors among adolescents. (7/3932)

The objective of the present study was to examine psychosocial correlates of diverse health-compromising behaviors among adolescents of different ages. The study population included 123,132 adolescents in sixth, ninth and 12th grades. Psychosocial correlates of substance abuse, delinquency, suicide risk, sexual activity and unhealthy weight loss behaviors were examined. Risk-taking disposition was significantly associated with nearly every behavior across age and gender groups. Other consistent correlates included sexual abuse and family connectedness. Correlates of health-compromising behaviors tended to be consistent across age groups. However, stronger associations were noted between sexual abuse and substance use for younger adolescents, and risk-taking disposition and school achievement were stronger correlates for older youth. The results suggest the presence of both common and unique etiological factors for different health-compromising behaviors among youth. The results emphasize the importance of focusing on positive 'risk-taking' experiences for youth in prevention programs; being sensitive to possible sexual abuse experiences among both female and male adolescents in health-care consultations; integrating strategies for improved family connectedness into health promotion efforts; and making school relevant for all adolescents.  (+info)

Prisoners of the proximate: loosening the constraints on epidemiology in an age of change. (8/3932)

"Modern epidemiology" has a primary orientation to the study of multiple risk factors for chronic noncommunicable diseases. If epidemiologists are to understand the determinants of population health in terms that extend beyond proximate, individual-level risk factors (and their biological mediators), they must learn to apply a social-ecologic systems perspective. The mind-set and methods of modern epidemiology entail the following four main constraints that limit engagement in issues of wider context: 1) a preoccupation with proximate risk factors; 2) a focus on individual-level versus population-level influences on health; 3) a typically modular (time-windowed) view of how individuals undergo changes in risk status (i.e., a life-stage vs. a life-course model of risk acquisition); and 4) the, as yet, unfamiliar challenge of scenario-based forecasting of health consequences of future, large-scale social and environmental changes. The evolution of the content and methods of epidemiology continues. Epidemiologists are gaining insights into the complex social and environmental systems that are the context for health and disease; thinking about population health in increasingly ecologic terms; developing dynamic, interactive, life-course models of disease risk acquisition; and extending their spatial-temporal frame of reference as they perceive the health risks posed by escalating human pressures on the wider environment. The constraints of "the proximate" upon epidemiology are thus loosening as the end of the century approaches.  (+info)