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Biomedical subjects

D Benton

Publications and source records attributed to D Benton.

At least 91 records · Page 5Linked to original sources
PubMed1995

Rapid changes in cellular immunity following a confrontational role-play stressor.

Recent laboratory studies have shown several immune system changes consistently associated with brief stress including increases in circulating natural killer (NK) cell numbers, increases in NK cell cytotoxicity (NKCC), increases in suppressor cytotoxic (CD8) T cell numbers, and decreases in the in vitro proliferative response to mitogen stimulation. In the present study, we use a confrontational role-play, which brings out responses varying from assertion to capitulation and examine the psychological, behavioral, physiological, and immune system responses to this task compared to a resting control task. Compared to the control condition, the brief confrontational role-play led to significant subjective and physiological arousal and increases in circulating NK (CD16, CD56) as well as large granular lymphocyte (CD57) cells and suppressor/cytotoxic T cells (CD8). There were also significant relationships between stress-related increases in the cardiovascular measures and the numbers of circulating NK cells. These findings support sympathetic nervous system activation as a primary mechanism for increases in NK cell numbers under challenge. These role-play results are generally consistent with those from other laboratory tasks such as mental arithmetic. However, in contrast to previously examined brief stressors, the role-play led to decreased NKCC adjusted for percentage of NK cells. This apparent differential change in NK cytotoxicity across different types of activating experimental tasks points to the importance of examining dimensions of the behavioral and emotional response to challenge or threat in addition to that of autonomic arousal.

Adult↗
PubMed1995

The impact of long-term vitamin supplementation on cognitive functioning.

The possibility that the taking of vitamin supplements may influence cognitive functioning was explored. One hundred and twenty-seven young healthy adults took either ten times the recommended daily dose of nine vitamins, or a placebo, under a double-blind procedure, for a year. After 12 months better performance on two measures of attention was found in females who had taken the vitamin supplement, even though the blood status of nine vitamins reached a plateau after 3 months. The use of regression equations demonstrated the association between improved thiamin status and improved performance on a range of measures of cognitive functioning in females rather than males. Although it was not possible to establish the reason for a beneficial response in females rather than males, the evidence that females respond differently to dietary factors was discussed.

Adolescent↗
PubMed1995

The effects of the opiate antagonist naloxone on measures of cellular immunity during rest and brief psychological stress.

This study investigated subjective, cardiovascular, and cellular immune system responses in 20 healthy young men during brief mental arithmetic stress compared with a video-watching control task. The role of endogenous opioids in mediating the immunological change to stress was examined by pre-task administration of the opiate antagonist naloxone. Immune changes were followed over a 1 hr post-task period. The results indicate significant physiological arousal and subjective distress as well as increases in NK cell cytotoxicity, numbers of circulating CD8 suppressor/cytotoxic T cells and NK lymphocytes following mental arithmetic but not the control task. Immune measures generally returned to baseline by 1 hr after the stress. Naloxone did not block the increase in NK cell activity or cell numbers following the stressor and had no effect on the other physiological or subjective measures. Thus, the results do not support endogenous opioids as a primary mechanism for immune changes to this type of acute stress. Naloxone did, however, increase NK cell cytotoxicity during the video task without effecting NK cell numbers, suggesting naloxone itself can increase per-cell NK cytotoxicity. Affective ratings for the week preceding testing were inversely related to the increase in NK cell numbers during mental arithmetic. If the increase in NK cell numbers under brief stress is part of an adaptive response to potential injury, then our data suggest that increases in general distress may impede normal immune system adaptation. Acute stress paradigms may be used as potential probes for investigations of individual differences in immune system responsivity.

Adult↗
PubMed1995

Blood glucose levels selectively influence memory for word lists dichotically presented to the right ear.

The relationship between performance on a dichotic listening task and blood glucose levels was examined. It was predicted that, if the ability of blood glucose to supply the brain with its basic fuel limits performance under conditions of cognitive demand, in a dichotic listening task information directed to the left hemisphere would be particularly susceptible to the level of blood glucose. Via headphones subjects heard lists of words directed to both ears, although randomly they were asked to attend to those directed to one ear. Those receiving a glucose drink recalled more of a list of words directed to the right ear and hence the left hemisphere. Subjects with low baseline blood glucose levels recalled more from the attended ear, and those with high baseline blood glucose more from the unattended ear. In those who received a glucose drink, a fail in blood glucose during the dichotic task was associated with a right ear superiority. The pattern of findings can be explained by the assumptions that under conditions of cognitive demand the supply of glucose to the brain limits performance and that there are individual differences in the ability to efficiently take glucose from the blood stream into the brain.

Adult↗
PubMed1995

Vitamin supplementation for 1 year improves mood.

The possibility that the taking of vitamin supplements may influence mood was explored. One hundred and twenty-nine young healthy adults took either 10 times the recommended daily dose of 9 vitamins, or a placebo, under a double-blind procedure, for a year. Males taking the vitamins differed from those taking the placebo in that they reported themselves as feeling more 'agreeable' after 12 months. After 12 months the mood of females taking the vitamin supplement was significantly improved in that they felt more 'agreeable', more composed and reported better mental health. These changes in mood after a year occurred even though the blood status of 9 vitamins reached a plateau after 3 months: this improvement in mood was associated in particular with improved riboflavin and pyridoxine status. In females baseline thiamin status was associated with poor mood and an improvement in thiamin status after 3 months was associated with improved mood.

Adolescent↗