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At least 469 records · Page 26Linked to original sources
PubMed1994

Effects of environmental enrichment on aggressive behavior, dominance hierarchies, and endocrine states in male DBA/2J mice.

Adult male mice (DBA/2J) siblings were housed three per cage for 6 wk, either in standard cages (SC) or in enriched cages (EC). Both attacks among group members and attacks against strange intruders were monitored once a week within each of 22 experimental groups. According to its attacking behavior, each mouse was categorized into one of three dominance categories: dominant, subdominant active, subdominant passive. Aggressive behavior and social organization were compared between the two types of housing conditions, and the effects of housing condition and dominance category on endocrinological and some organometrical parameters were analysed. The main findings were: (a) Mice in EC attacked intruders significantly more frequently compared to mice in SC; (b) In EC groups the position of the dominant male was less stable than in SC groups; (c) Plasma corticosterone titers (PCT) were significantly elevated in EC. Activities of tyrosinehydroxylase (TH) and phenylethanolamine-N-methyltransferase (PNMT) did not differ significantly between the housing conditions; (d) TH and PNMT activity were significantly enhanced in the dominant males of SC groups compared to subdominant passive males. Intermediate activities for both enzymes were determined for subdominant active males; and (e) PCT were significantly elevated in dominant males of the EC groups compared to subdominant active and subdominant passive males and also compared to the dominant males in the SC groups. Findings suggest that keeping adult male mice in structured cages can result in increased aggression towards intruders, a change in the social organization, and altered endocrine states, depending on the individual dominance position.

Aggression↗
PubMed2000

Conditioned fear to environmental context: cardiovascular and behavioral components in the rat.

This study compares the time course of the cardiovascular changes (mean arterial blood pressure, heart rate) and behavioral changes (freezing, rearing, grooming and activity) evoked by 30 min long exposures to a footshock chamber before and after conditioning with footshocks. The main finding is that the conditioned fear evoked by re-exposure to the footshock chamber after conditioning is associated with a prolonged freezing response, a marked rise in mean arterial pressure (+35 mm Hg above a resting baseline of 105 mm Hg) and a delayed rise in heart rate. The pattern of behavioral and cardiovascular changes is the same as with conditioned fear to a discrete stimulus but the effect is a lot longer.

Animals↗
PubMed2000

Energy metabolism and obesity.

Over the long-term, most adult humans are able to maintain body energy stores through the process of energy balance, which regulates how much energy is consumed to match how much energy is expended. Energy expenditure is required for resting metabolic rate to maintain basic physiologic functions (e.g., heart beat, muscle function, respiration) and metabolize, digest, and store food that is consumed as well as for physical activity. Resting metabolic rate is the largest component of daily energy expenditure, and physical activity-related energy expenditure is the most variable. Cross-sectional studies in children and adults have shown that energy expenditure, including physical activity-related energy expenditure, are similar in lean versus obese subjects, especially after controlling for differences in body composition. A major limitation for most studies that have examined the role of energy expenditure in the cause of obesity is their cross-sectional design. Some longitudinal studies support the idea that reduced energy expenditure is a risk factor for the development of obesity, but most do not. There are several possibilities that could account for such discrepant findings. First, the ambiguous findings in the literature might be explained by the possibility that differences in energy expenditure and physical activity and their impact on the development of obesity are different at the various stages of maturation. Second, there could be individual differences in the impact of altered energy expenditure on the regulation of energy balance. The impact of energy expenditure on the cause of obesity could vary among different subgroups of the population (e.g., boys versus girls and different ethnic groups) and could have a differential effect within individuals at different stages of development. A specific example is the lower energy expenditure in Pima Indians, which predisposes to increased risk of obesity. It remains to be seen whether the lower metabolic rates that have been observed in African-Americans will relate to subsequent weight gain. It is conceivable that susceptible individuals fail to compensate for periodic fluctuations in energy expenditure. Third, given that obesity can arise as a result of a small energy balance over time, it is unlikely that existing techniques are capable of measuring such small differences. Finally, it can be argued that a focus on energy metabolism as a possible explanation of obesity is unlikely to yield interesting information because of the wide range in energy expenditure in the population even after adjusting for body composition. The major dependent variable that needs to be examined in relation to the cause of obesity is not energy expenditure but change in energy balance over time and the ability to regulate body energy stores. Given that the sudden change in obesity prevalence has occurred during a time of rapid environmental and cultural changes, additional focus on the behavioral and environmental effects on regulation of energy balance is warranted.

Adult↗
PubMed1999

Dose assessment and behavior of tritium in environmental samples around Wolsong nuclear power plant.

For the estimation of the dispersion trend of tritium discharged from the Wolsung nuclear power plant, the present level of tritium in environmental samples in the vicinity of the Wolsong site has been studied. On the basis of tritium concentrations in environmental samples, the effective dose due to tritium has been estimated for an individual and population within a 16 km radius from the Wolsong site. The annual effective dose of tritium to an inhabitant around the Wolsong site ranged from 0.15 microSv y-1 to 1.3 microSv y-1. The dose level was negligible and much lower than some applicable standards, i.e. the limit on exposure from nuclear fuel cycle to the general public as recommended by ICRP (1 mSv y-1) or US EPA's limit (0.25 mSv y-1). The collective dose to the total population within a 16 km radius from the site, 1.2 x 10(-2) man.Sv y-1 was much lower than 1 man.Sv y-1, an applicable criterion for the so-called "exemption" of radiation sources and practices from regulatory control.

Environmental Monitoring↗
PubMed2002

The social-environmental context of violent behavior in persons treated for severe mental illness.

OBJECTIVES: This study examined the prevalence and correlates of violent behavior by individuals with severe mental illness. METHODS: Participants (N = 802) were adults with psychotic or major mood disorders receiving inpatient or outpatient services in public mental health systems in 4 states. RESULTS: The 1-year prevalence of serious assaultive behavior was 13%. Three variables-past violent victimization, violence in the surrounding environment, and substance abuse-showed a cumulative association with risk of violent behavior. CONCLUSIONS: Violence among individuals with severe mental illness is related to multiple variables with compounded effects over the life span. Interventions to reduce the risk of violence need to be targeted to specific subgroups with different clusters of problems related to violent behavior.

Adult↗
PubMed1989

[The effect of increased environmental temperature on the behavior of physiologic parameters in bicycle ergometry within the scope of the physical endurance limit].

For determination of the endurance limit range, 8 healthy male probands aged between 20 and 26 years loads had carried out for one hour on a bicycle ergometer at an ambient temperature of +20 degrees C, +28 degrees C and +35 degrees C. Staying in an ambient temperature of 35 degrees C leads to a decrease in the physical endurance limit in an order of magnitude of 10 W. At 20 degrees C, in the endurance range the following values result (mean +/- s): load 68+/- 10.3 W, heart rate 113.6 +/- 5.8 beats per min., net heart rate 31.8 +/- 2.4 beats per min., oxygen uptake 1340 +/- 170 ml per min., auditory canal temperature 36.5 +/- 0.24 degrees C, sweat rate 275 +/- 143 g. At 35 degrees C, the endurance limit is attained at the following values: 57 +/- 10.6 W, heart rate 125 +/- 11.8 beats per min., net heart rate 27.4 +/- 3.6 beats per min., oxygen uptake 1210 +/- 130 ml per min., auditory canal temperature 37.2 +/- 0.3 degrees C, sweat rate 577 +/- 96 g.

Exercise Test↗
PubMed1987

Environmental temperature and maternal behavior in Rattus norvegicus.

In 14 female rats the daily duration of selected patterns of maternal behavior was registered for 10 successive days (from the 4th till the 13th day postpartum) for 180 min each day. On certain days the home cages of 7 females (experimental group) were cooled for 8 h, while the remaining 7 females constituted a control group. During the days of cooling the experimental females devoted to the care- giving behavior much more time than during the days without cooling. The drop in temperature influenced the intensity of maternal behavior not only in the early postpartum days, but also on the following days, and that behavior altered repeatedly according to temperature changes. The behavioral responses of females to the actual temperature changes emerge during the first 90 min of cooling. The results indicate that in the course of one maternal cycle the intensity of care-giving activities can be modified many times and relatively quickly, according to temperature changes.

Animals↗
PubMed1995

Emerging issues in lifestyle, social, and environmental interventions to promote behavioral change related to prevention and control of hypertension in the African-American population.

Prevention of hypertension must play a more prominent role in health care, in the education of young people, and in the public policy arena if we are committed to reduce mortality from cardiovascular disease. Some steps individuals can take to lessen the risk of stroke or coronary heart disease include: If you are obese and hypertensive, you should reduce total calories and lose weight. Substitute olive oil or canola oil for vegetable oils to increase your intake of monounsaturated fatty acids. Try the Mediterranean diet. Start a program of aerobic exercise or increase the amount you are currently doing. Reduce salt intake. Reduce alcohol consumption. Stop smoking. If you have hypertension and tend to overrespond to stress, try relaxation and biofeedback techniques, which according to some studies may produce a modest reduction in blood pressure in some individuals with mild hypertension. Increase the amount of fiber in the diet by increasing the amount of grains, fruit, and vegetables. Have your renin level tested. A "population" approach should be incorporated into medical school curricula to encourage and train caregivers to consider social, cultural, and economic factors affecting patients. Historically black colleges, public and private elementary and secondary schools, and churches can provide leadership in this nation for educating African Americans in the prevention and control of high blood pressure. In conclusion, we already have the information we need from research to close the mortality gap between whites and African Americans in cardiovascular disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Black People↗
PubMed1990

Hypothalamic histamine modulates adaptive behavior of rats at high environmental temperature.

Histamine content in the rat hypothalamus was lower at 4 degrees C and higher at 31 degrees C compared to that at 21 degrees C. Pretreatment with alpha-fluoromethylhistidine, a 'suicide' inhibitor of histamine decarboxylase, attenuated both the increased level of hypothalamic histamine and rat adaptive behavior at 31 degrees C. Increase of histamine content in the hypothalamus appears to be an important factor contributing to rat adaptive behavior to high environmental temperature.

Adaptation, Physiological↗