Biomedical subjects

M F Muldoon

Publications and source records attributed to M F Muldoon.

59 records · Page 4Linked to original sources

PubMedDate not supplied

Demonstration of an association among dietary cholesterol, central serotonergic activity, and social behavior in monkeys.

Epidemiologic studies link plasma cholesterol reduction to increased mortality rates as a result of suicide, violence, and accidents. Deficient central serotonergic activity is similarly associated with violence and suicidal behavior. We investigated the relationship among dietary and plasma cholesterol, social behavior, and the serotonin system as a possible explanation for these findings. Juvenile cynomolgus monkeys (eight female and nine male) were fed a diet high in fat and either high or low in cholesterol. We then evaluated their behavior over an 8-month period. Plasma lipids and cerebrospinal fluid metabolites of serotonin, norepinephrine, and dopamine were assessed on two occasions, at 4 and 5.5 months after the initiation of behavioral observations. Animals that consumed a low-cholesterol diet were more aggressive, less affiliative, and had lower cerebrospinal fluid concentrations of 5-hydroxyindoleacetic acid than did their high-cholesterol counterparts (p < .05 for each). The association among dietary cholesterol, serotonergic activity, and social behavior was consistent with data from other species and experiments and suggested that dietary lipids can influence brain neurochemistry and behavior; this phenomenon could be relevant to our understanding of the increase in suicide and violence-related death observed in cholesterol-lowering trials.

Aggression↗

PubMedDate not supplied

Adrenergic blockade ameliorates cellular immune responses to mental stress in humans.

This study evaluated the sympathoadrenal modulation of behaviorally evoked immune responses by administration of a nonselective adrenoceptor antagonist (labetalol) to subjects exposed to mental stress. In a 2 x 2 factorial design, subjects were assigned to a labetalol or saline condition and, within each condition, were exposed either to acute laboratory stress or no stress (control). Lymphocyte subsets, natural killer (NK) cell cytotoxicity, and T cell proliferation to phytohemagglutinin and concanavalin A were assessed pre-experimentally, at baseline after infusion and after 18 minutes of mental stress (or rest). By comparison with the other three conditions, the saline-stress group showed a greater peripheral NK cell number and cytotoxicity, lower mitogenic response to phytohemagglutinin and concanavalin A, and diminished ratio of CD4:CD8 cells after the stressor. As predicted, immune responses did not differ among the remaining groups (labetalol-stress, saline-rest, labetalol-rest). Group differences in NK cell cytotoxicity were not significant after controlling for differences in NK cell numbers. These findings demonstrate that the occurrence of certain immunologic responses to acute psychological stress are dependent on concomitant activation of the sympathetic nervous system.

Adolescent↗

PubMedDate not supplied

Serum cholesterol and intellectual performance.

OBJECTIVE: The current investigation sought to determine whether intellectual performance is related to serum lipid concentrations. METHODS: Subjects were 177 healthy, Caucasian adult males and females, aged 25 to 60 years, with widely varying total cholesterol concentrations. Crystallized intelligence was estimated from the Information and Vocabulary subtests of the Wechsler Adult Intelligence Scale, Revised (WAIS-R). Fluid intelligence was estimated from the WAIS-R Block Design subtest, and from a computerized version of the Letter Rotation test. RESULTS: Controlling for age, better performance on both Information and Vocabulary subtests was associated with lower total and low-density lipoprotein (LDL) cholesterol and triglyceride concentrations (r's = -.24 to -.35, p's < .005). In contrast, better performance on Block Design was correlated with higher total and LDL cholesterol (r's = .22 to .23, p's < .005). Letter rotation response latency was unrelated to serum lipids. CONCLUSION: These opposing relationships between serum cholesterol and different dimensions of intellectual performance, on the one hand, may reflect the propensity of knowledgeable individuals to consume low fat diets, and on the other hand, suggest that serum cholesterol concentration may be a correlate of brain nutrients important to mental efficiency.

Adult↗

PubMedDate not supplied

Ambulatory blood pressure responses and the circumplex model of mood: a 4-day study.

BACKGROUND: The relation between mood or emotions and concurrent ambulatory blood pressure responses holds both fundamental and clinical interest. METHODS: The primary sample consisted of 69 normotensive or borderline hypertensive but otherwise healthy adult males. The validation sample consisted of 85 healthy male undergraduate college students. Both samples underwent half-hourly 24-hour ambulatory blood pressure measurements on four separate workdays, 1 week apart. At each ambulatory measurement, subjects recorded their behavior, environment, and mood. The circular mood scale, a circular visual analogue scale based on the circumplex model of mood, was used to reflect the totality of a participant's affective state space. Longitudinal random effects regression models were applied in the data analysis. RESULTS: The results for both samples were quite similar. Sleep and posture had the greatest influence on ambulatory blood pressure and heart rate. The effects of the environmental setting, social setting, and consumption were modest but statistically significant. Independent of these covariates, mood exerted a significant effect on blood pressure and heart rate. Relative to the "mellow" default category, blood pressure increased both for "anxious/annoyed" and "elated/happy" and decreased during "disengaged/sleepy" mood. The range of mood-related blood pressure estimates was 6.0/3.7 mm Hg. CONCLUSIONS: The pattern of blood pressure responses suggests that they were related to the degree of engagement of a mood rather than the degree of unpleasantness. The hypothesis that posits that negative affect-related cardiovascular reactivity mediates the observed correlation between negative affect and disease risk should be reconsidered.

Adolescent↗

PubMedDate not supplied

Does socioeconomic status relate to central serotonergic responsivity in healthy adults?

OBJECTIVE: We tested whether low SES was associated with reduced central serotonergic responsivity in a community sample of adult men and women and the extent to which standardized measures of aggression and impulsivity mediate the association. METHODS: A total of 270 adults who were enrolled in a clinical trial on the neurobehavioral effects of lipid lowering were given a neuropharmacologic challenge (plasma prolactin response to orally administered fenfluramine) to measure serotonergic responsivity. Measures of family income and educational attainment were standardized and summed to derive an overall index of SES. Scores from the Brown-Goodwin Life History of Aggression interview, the Barratt Impulsiveness Scale, and the Angry Hostility subscale from the NEO Personality Inventory were also standardized and summed to form an aggression/impulsivity score. RESULTS: Low SES was correlated with low prolactin responses to the fenfluramine challenge in the full sample (r = .15) as well as in whites, men, and women evaluated separately. Although the standardized SES score was correlated inversely with aggression/impulsivity measure (r = -.19, p < .01), the association between SES and prolactin responses remained significant when statistical adjustments were made for age, gender, body mass index, and aggression/impulsivity scores. CONCLUSIONS: Blunted serotonergic responsivity is associated with low social class as measured by annual family income and educational attainment.

Adult↗