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Biomedical subjects

J Rodin

Publications and source records attributed to J Rodin.

At least 19 recordsLinked to original sources
PubMed1992

Effect of chronic stress and exogenous glucocorticoids on regional fat distribution and metabolism.

It has been proposed that increased glucocorticoid hormones and decreased sex hormones affect regional fat metabolism and distribution. In the present work, it was hypothesized that chronic, uncontrollable stress, known to affect the pituitary-adrenal and pituitary-gonadal axes might, therefore, lead to differences in regional fat accumulation. In comparison with controls, male Sprague-Dawley rats stressed for 28 days, had significantly larger adipocytes. In addition, a tendency for a heavier fat pad and an increased lipoprotein lipase activity in the mesenteric depot was suggested. No significant changes were seen in epididymal, retroperitoneal, and inguinal regions. In order to study if the effects observed could be attributed to increased glucocorticoids, the response to a direct administration of supraphysiological doses of corticosterone, given either in the drinking water or via subcutaneous implantation of corticosterone pellets, was studied. Increased fat accumulation was shown in all fat depots in a dose-response fashion, but was significantly more pronounced in the mesenteric region. It was concluded that mesenteric fat tissue may respond to stress in a different manner from other fat depots. Glucocorticoids seem to be partly, but not solely, responsible for the changes observed in adipose tissue metabolism and distribution following exposure to uncontrollable stress.

Adipose Tissue↗
PubMed1992

Modulation of human natural killer cell activity by exposure to uncontrollable stress.

Changes in natural killer cell (NK) activity and proportions of circulating T and NK lymphocyte subsets were assessed in adult males immediately after exposure to controllable or uncontrollable stress (noise) as well as 24 and 72 h later, in order to track the time course of the effects of stress. The role of control-relevant personality variables as moderators of the stress-immunosuppression relationship was considered. Subjects who perceived they had control over the noise as well as no-noise "control" subjects showed no reduction in NK activity. By contrast, subjects who perceived that they had no control over the stressor showed reduced NK activity immediately after the conclusion of the first 20-min stress session, and the reduced NK activity was found as long as 72 h later. Optimism and one's desire to be in control enhanced the negative impact of uncontrollable noise on NK activity. No differences between conditions were found on number of NK cells or a variety of T cell subsets. The results suggest the importance of perceived control in moderating the short- and long-term effects of stress on NK activity.

Adolescent↗
PubMed1992

Women and AIDS in the United States: epidemiology, natural history, and mediating mechanisms.

The number and proportion of women with the human immunodeficiency virus (HIV)1 and acquired immunodeficiency syndrome (AIDS) have increased rapidly throughout the past decade. Despite these increases, research attention on women with AIDS has been relatively scarce until recently. It is likely that there are important sex differences at all phases of the disease process-from prevention, through viral exposure, diagnosis, and living with HIV, to treatment for AIDS. Therefore, research findings from studies of men may not all be extended reliably to women with HIV and AIDS. In this article, we review the literature on U.S. women in particular and discuss what differentiates these women from their male counterparts with the disease. We begin with an epidemiologic review and description of the natural history of the disease to lay the foundation for a more complete understanding of the biological and psychosocial factors relevant to AIDS in women. The association between psychosocial mechanisms--including stress, control, and social support--and immune-mediated disease outcomes is discussed in detail. Implications for research, prevention, and treatment also are considered.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Relation of level of exercise, age, and weight-cycling history to weight and eating concerns in male and female runners.

We examined the association between level of exercise and degree of weight preoccupation in a large sample of male and female runners, as well as risk factors posited to influence weight and eating concerns in the general population. Subjects were 2,459 males and 1,786 females who had completed a questionnaire on weight and eating concerns in a national running magazine. Eight percent of the males and 24% of the females had symptomatic scores on the Eating Attitudes Test (EAT). Exercise level, defined as weekly running mileage, was positively associated with excessive weight and eating concerns in males but not in females. Both sexes with a history of weight cycling were more likely to have symptomatic EAT scores than those with no such history. These results highlight the importance of studying these concerns in males as well as females and of examining the role of exercise level and weight-cycling history in the development of serious weight preoccupations.

Adolescent↗
PubMed1992

Determinants of change in perceived health in a longitudinal study of older adults.

To determine the factors that are predictive of a negative decline in perceived health in a longitudinal study of 251 men and women aged 62 and older, we developed a "synthetic" cohort of individuals who experienced a decline in perceived health between two time points and a control cohort of those who did not. The longitudinal design of the study made it possible to evaluate the effects of "baseline" predictors, gathered prior to the time interval during which the reported change in perceived health occurred, in addition to measures assessed at the two time points between which the change in health was reported. Hierarchical logistic regression models were used to examine the effect of demographic, psychosocial, and illness measures on change in perceived health. These analyses revealed that increases in new illnesses, increased physician visits, and worsening of preexisting conditions (in subjects who had higher feelings of self-efficacy) were all associated with a decline in perceived health, after controlling for the effects of baseline illnesses and medication use. After accounting for these effects of changes in objective illness indicators, we found that changed psychosocial factors also predicted a decline in perceived health. Lower life satisfaction and higher depression at baseline were predictive of a later decline in perceived health. In addition, data collected at the third consecutive time point were evaluated to assess determinants of a sustained vs transient decline in perceived health. A sustained decline in perceived health was associated with increased depression and decreased self-efficacy.

Aged↗
PubMed1992

Pregnancy alters blood pressure responses to psychological and physical challenge.

The purpose of the study was to evaluate the effect of the substantial changes in female reproductive hormones that occur during normal pregnancy on cardiovascular responses to psychological and physical challenges. Twenty-one healthy normotensive women performed serial subtraction, mirror image tracing, and isometric handgrip exercise tasks prior to pregnancy and again during the second trimester of pregnancy. A control group of 34 healthy women who did not intend to become pregnant and were nonpregnant were also tested in the same protocol twice, 6-10 months apart. Results showed that the pregnant women exhibited a reduced diastolic blood pressure response to all three tasks, relative to their pre-pregnancy levels, whereas nonpregnant controls did not change in their diastolic blood pressure response across time. These results are consistent with the hypothesis that elevations in female reproductive hormones diminish blood pressure responses during challenge because of dampened sympathetic nervous system activity.

Adolescent↗
PubMed1991

Food cravings in relation to body mass index, restraint and estradiol levels: a repeated measures study in healthy women.

The study considered the nature and extent of cravings in 108 healthy women between the ages of 20 and 37 who were tested at four time points over a 2-year period. There was substantial consistency over the four widely separated time points (3 months-1 year) in the types of foods craved, with chocolate and ice cream highest on the list, followed by fatty and spicy foods, and sweets. Women with a higher body mass index reported more consistent cravings for salty foods, especially those with high flavor intensity. There were no significant relationships between dietary restraint and the number, frequency or types of cravings. There were also no strong relationships between estradiol levels and the number, frequency or types of cravings women reported in the whole sample. The data suggest that women have a stable core of foods for which they experience cravings, relatively independent of estradiol levels, BMI or degree of dietary restraint.

Adult↗
PubMed1991

Effects of pure sugar vs. mixed starch fructose loads on food intake.

Using a within-subject design, we gave subjects three different 520-530 kcal preloads in the form of puddings in a randomized fashion at weekly intervals. The puddings contained either 50 g of fructose or glucose as the sole carbohydrate source in a protein and fat mixture, or 50 g fructose plus 15 g of starch. Food intake was assessed 2.25 h after the preload was completed. Blood was drawn throughout and assayed for concentrations of glucose and insulin. When the preload contained fructose alone as the sole source of carbohydrate, subjects ate significantly fewer calories and less fat than when the preload contained glucose alone. When starch was added to the fructose preload, there was no significant reduction in calorie and fat intake. Effects on food intake paralleled the rise in plasma insulin levels produced by the different preloads. Implications for use of fructose as an adjunct to weight control efforts are discussed.

Adult↗
PubMed1991

Explanatory style and cell-mediated immunity in elderly men and women.

Correlated pessimistic explanatory style--the belief that negative events are caused by internal, stable, and global factors--with lowered immunocompetence in a sample of 26 older adults. Two measures of cell-mediated immunity--T-helper cell/T-suppressor cell ratio and T-lymphocyte response to mitogen challenge--were lower in individuals with a pessimistic style, controlling for the influence of current health, depression, medication, recent weight change, sleep, and alcohol use. A relative increase in the percentage of T-suppressor cells seemed to underlie this immunosuppression. Although the mechanism by which explanatory style might influence immune function remains unknown, we speculate that a pessimistic style might be an important psychological risk factor--at least among older people--in the early course of certain immune-mediated diseases.

Aged↗
PubMed1991

Stress reactivity and exercise training in premenopausal and postmenopausal women.

Examined the influence of ovarian function on psychophysiological stress responses and determined if aerobic exercise reduced stress reactivity. Fifty premenopausal and postmenopausal women initially were subjected to a public speaking task and an ice-on-the-forehead procedure, during which time their blood pressure and heart rate were monitored and continuous blood samples were obtained. Subjects also underwent aerobic fitness evaluations with a maximum-exercise treadmill test. Subjects were then randomly assigned to a 12-week exercise program of either aerobic exercise (e.g., walking and jogging at a prescribed exercise intensity) or non-aerobic strength and flexibility training and were then reevaluated. Results indicated that postmenopausal women exhibited lower resting epinephrine levels but greater epinephrine reactivity to the speaking task compared to the premenopausal women. There were no differences between premenopausal and postmenopausal women with respect to cardiovascular or catecholamine responses during the cold challenge. Premenopausal and postmenopausal women also achieved comparable improvements in aerobic fitness. However, results of the mental stress testing were complex and provided only partial support for the role of aerobic exercise in reducing stress responses.

Arousal↗
PubMed1991

Children's representations of "everyday" aspects of health and illness.

Moving beyond a focus on children's conceptions of causation, the study sought to (a) identify and evaluate additional dimensions along which young children's conceptions of illness might be organized and (b) to discover how young children also understand health concepts related to nutrition and routine preventive medical examination. 27 healthy preschool children, ages 4-6 were interviewed about their conceptions of common illness, knowledge of basic nutrition, and understanding of medical procedures and instruments associated with a standard pediatric examination. The findings demonstrated that children understand five characteristics of illness representations, which have also been identified in adults. They include causation, identity, consequence, time line, and cure. Associations among illness dimensions, concepts of nutrition, and knowledge about routine medical examinations were also found and are discussed in terms of their implications for future research.

Adaptation, Psychological↗
PubMed1979

Environmental determinants of memory improvement in late adulthood.

Two studies were conducted with nursing home residents to determine whether memory could be improved. This was accomplished by increasing the cognitive demand of the environment and then varying the extent to which residents were motivated to attend to and remember these environmental factors. In Study 1, motivation to practice recommended cognitive activities was manipulated by varying the degree of reciprocal self-disclosure offered by interviewers in a series of dyadic interactions. In Study 2, motivation to practice recommended cognitive activities was manipulated by varying whether positive outcomes were contingent on attending to and remembering these activities, which increased in demand over time. Whether as a function of interpersonal (Study 1) or practical (Study 2) incentives, engaging in cognitive activity resulted in improvement on standard short-term memory tests, including probe recall and pattern recall, as well as in improvement on nurses' ratings of alertness, mental activity, and social adjustment for experimental groups relative to controls.

Aged↗
PubMed1979

Metabolic and behavioral differences between dieting and intestinal bypass.

The present studies were designed to compare physiological and behavioral changes produced by weight loss induced with dieting and the weight loss which follows intestinal bypass. A group of 7 grossly obese individuals were hospitalized in a metabolic unit and studied at their initial weight after 4 weeks on a hypocaloric diet and again following a comparable weight loss after intestinal bypass surgery. The score indicating depression increased after dieting, but returned to initial levels after bypass. A number of other behavioral changes were recorded including a reduction in the time spent thinking about food, the time when the individual felt hungry and a greater percentage of time when they felt "full". After bypass, the patients also selected and ate smaller quantities of food. There were no metabolic differences following the period of dieting. Among the metabolic changes after bypass were an increase in glycerol and a decrease in insulin. The possible relationships between the metabolic and behavioral changes have been reviewed.

Blood Glucose↗
PubMed1977

Long-term effects of a control-relevant intervention with the institutionalized aged.

Elderly nursing home residents who were tested as part of an intervention designed to increase feelings of choice and personal responsibility over daily events were reevaluated 18 month later. Nurses' ratings and health and mortality indicators suggest that the experimental treatment and /or the processes that it set in motion had sustained beneficial effects.

Activities of Daily Living↗
PubMed1977

Effects of degree of obesity, age of onset, and weight loss on responsiveness to sensory and external stimuli.

Four experiments tested responsiveness to external and sensory stimuli in female human subjects who differed in degree of overweight and in age of onset of their obesity. The effects of weight loss upon external responsiveness were assessed by testing subjects before and after weight reduction in order to determine the role of energy deficit and deprivation in mediating heightened responsiveness to external cues. There was no significant positive correlation between degree of overweight and degree of external responsiveness. In general, the age of onset of the obesity was also not a relevant factor in the degree of externality. Weight loss did not change responses to visual and cognitive cue salience manipulations in measures of feeding, emotionality, time perception, and short-term recall, whereas responsiveness to variations in palatability increased following weight reduction. While external cue responsiveness does not appear to result from adiposity per se or from deprivation, responsiveness to taste stimuli may reflect these parameters. The role of external and sensory cues in the development and maintenance of obesity is discussed.

Adolescent↗
PubMed1977

Treatment of obesity: comparison of physician and nonphysician therapists using placebo and anorectic drugs in a double-blind trial.

In a randomized double-blind trial, 60 obese patients were assigned in groups of 12 to five therapists. The patients for each therapist were then randomly assigned in groups of four to placebo or one of two preparations of mazindol. Ninety-three percent of the patients completed the nine weeks of treatment. Weight loss averaged 1.1 lb per week and there was no advantage to pharmacological agents over placebo. However, there were significant differences between therapists. Weight loss by the patients assigned to physicians was no better than for those assigned to nonphysician personnel, but there were significant differences between individual nonphysician personnel. These findings support the concept that nonphysician personnel may be effective in treating many obese patients. In addition, we could not find a significant effect of either form of mazindol when compared to placebo.

Adolescent↗