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Biomedical subjects

C M Stoney

Publications and source records attributed to C M Stoney.

At least 37 records · Page 2Linked to original sources
PubMed1990

T-lymphocyte reactivity during the menstrual cycle in women.

Reactivity of blood lymphocytes to nonspecific mitogenic stimulation with phytohemagglutinin (PHA) was measured in nine healthy, regularly cycling women at three phases of their menstrual cycles corresponding to peak levels of estradiol (midfollicular phase), peak levels of progesterone (midluteal phase), and the lowest levels of both hormones (menstrual phase). Sampling points were verified by radioimmunoassay of estrogen, progesterone, luteinizing hormone, and follicle-stimulating hormone. There were significant increases in reactivity associated with an increasing concentration of PHA and with autologous plasma vs AB plasma. However, no differences were found in reactivity to PHA over the three menstrual cycle phases and correlational analyses indicated no relationship between counts and any of the hormones measured.

Adolescent↗
PubMed1990

Influences of the normal menstrual cycle on physiologic functioning during behavioral stress.

The purpose of this study was to evaluate the influence of the normal menstrual cycle on lipoprotein, cardiovascular, and neuroendocrine stress responses. Fifteen normally-cycling, healthy women participated in a series of behavioral tasks during the menstrual, follicular, and luteal phases of their menstrual cycle. These women had established menstrual cycle regularity for the three months prior to enrollment in this study, were free from menstrual cycle disturbances, biochemically confirmed that they ovulated, and displayed appropriate patterns of reproductive hormone fluctuations during the study period. Heart rate, blood pressure, low density lipoprotein-cholesterol, and total cholesterol all demonstrated significant elevations from baseline levels during tasks. No differences in the magnitude of stress responses during the three menstrual cycle phases were noted for any physiological variable. We conclude that the hormonal fluctuations that occur in healthy, normally-cycling women during the menstrual cycle do not influence the stress responses that were investigated here. Significant influences of menstrual cycle phase previously reported in the literature, albeit not in a consistent direction, may have been due to the recruitment of women with menstrual cycle irregularities, and to the failure to adequately verify menstrual cycle phase.

Adult↗
PubMed1990

Changes in and stability of cardiovascular responses to behavioral stress: results from a four-year longitudinal study of children.

This study examined the changes in and stability of cardiovascular responses to behavioral stress among 132 children in a 4-year longitudinal study. Children's heart rate and blood pressure were measured at rest and while performing 3 tasks: serial subtraction, mirror image tracing, and isometric exercise. This procedure was followed at study entry when children were in grades 2-12 (ages 6-18 years) and at follow-up when children were in grades 6 through post-high school (ages 11-21 years). Results showed that blood pressure and heart rate responses during the tasks were reliable across time for all measures except heart rate responses during isometric exercise. Systolic blood pressure responses to all tasks increased with age for boys, but not for girls. These results support the notion that cardiovascular responses to behavioral stress are a stable individual difference variable.

Adolescent↗
PubMed1989

Premenopausal and postmenopausal women differ in their cardiovascular and neuroendocrine responses to behavioral stressors.

Middle-aged (45-51 years) women performed four tasks while their heart rate, blood pressure, and plasma catecholamines were measured. The tasks were serial subtraction, mirror image tracing, speech, and postural tilt. The speech task was considered to be particularly relevant to women because of its emphasis on social skills. Fifteen premenopausal women reported menstruating regularly and were tested in the early follicular phase. Sixteen postmenopausal women reported not menstruating for at least 12 months and their hormonal status was verified by serum levels of follicle-stimulating hormone. Results showed that postmenopausal women exhibited greater increases from baseline in heart rate during all tasks, relative to premenopausal women, with a particularly pronounced increase during the speech task. Postmenopausal women exhibited greater increases from baseline in systolic blood pressure and epinephrine, relative to premenopausal women, during the speech task only. Explanations for the stressor-specific effect of menopausal status were discussed. The results suggest that reproductive hormones may interact with stressor characteristics to determine middle-aged women's physiological responses to stress.

Arousal↗
PubMed1986

Family characteristics and school achievements of type A children.

We examined the familial characteristics of Type A children and the consequences of Type A behaviors for children's classroom achievements. A maximum of 156 boys and 190 girls enrolled in elementary and middle schools and their parents participated in various aspects of the data collection procedures and analyses reported in this article. Results showed that Type A children were not more likely to have families with a history of cardiovascular-related diseases or families of upper socioeconomic status. Young Type A boys, but not girls, had Type A mothers and fathers, suggesting an early modeling of Type A behaviors by boys. Competitive boys and girls and Type A girls had higher achievement test scores and classroom grades, independent of IQ test scores, than did relatively noncompetitive children and Type B girls, respectively. Thus, the competitive aspect of Type A leads to important early achievements, independent of ability, perhaps because care givers and teachers respond to Type A behaviors of children by encouraging them to continue to strive to achieve. Gender differences in the findings were also discussed and related to the adult literature.

Achievement↗
PubMedDate not supplied

A comparison of biofeedback-assisted cardiodeceleration in type A and B men: modification of stress-associated cardiopulmonary and hemodynamic adjustments.

The primary purpose of this experiment was to examine the cardiac effects of instructions and biofeedback to reduce heart rate during both rest and a behavioral stressor. A second purpose was to assess respiratory, hemodynamic, and metabolic function in conjunction with heart rate. A final aim was to compare the effects of biofeedback on Type A and B men. Type A subjects fell in the upper 10% of the distribution of Jenkin's Activity Survey scores and Type B subjects fell in the lower 10%. Subjects experienced one of three instructional sets during an initial session: instructions to reduce heart rate with biofeedback; instructions to reduce heart rate without biofeedback; and instructions to sit quietly. During a second session, all subjects received identical instructions prior to the behavioral stressor. Heart rate, pulmonary gas exchange, and ventilation were measured breath-by-breath. During the first session, the groups did not differ in any measured parameter, but Type As had higher heart rates than did Type Bs across all conditions. During the second session, subjects given instructions to reduce heart rate with and without biofeedback did not differ in heart rate; as expected, however, both of these groups had smaller increases in heart rate than did the control group. Interestingly, the tachycardia of the control group occurred without an increase in oxygen consumption, indicating a cardiac-metabolic dissociation in this group. The modification of heart rate without a concomitant change in metabolism is important in understanding the association between cardiac and metabolic function.

Biofeedback, Psychology↗
PubMedDate not supplied

Influences of sex and age on cardiovascular responses during stress.

The present investigation examined the influence of sex and age on blood pressure and heart rate responses in 125 women, 93 men, 121 girls, and 96 boys to three standardized stressors: serial subtraction, mirror-image tracing, and isometric handgrip. With baseline measures and body mass index controlled for, analyses of covariance showed that adults had greater systolic blood pressure responses than did children; men had greater blood pressure responses to all stressors than did women; and high school boys had greater systolic blood pressure responses than did high school girls. In addition, adults had smaller heart rate responses during isometric handgrip than did children, and high school students had smaller heart rate responses during all tasks than did the remaining, younger students. These results show that sex and age are important determinants of the magnitude of cardiovascular adjustments during stressors. The implications of these results are discussed in light of sex differences in coronary heart disease morbidity and mortality.

Adolescent↗
PubMedDate not supplied

Familial aggregation of blood pressure and heart rate responses during behavioral stress.

Parent-offspring and sibling resemblances in blood pressure and heart rate responses to behavioral stress were evaluated in a sample of 142 families residing in an upper-middle-class community in the Pittsburgh metropolitan area between 1983 and 1985. The sample consisted of 121 daughters and 96 sons ranging in age from 7 to 18 years, and 141 mothers and 119 fathers ranging in age from 31 to 62 years. Three stressors were presented to all participants: serial subtraction, mirror image tracing, and isometric handgrip exercise. Multivariate analyses of the stress responses were based on maximum likelihood estimations of the magnitude of association, which provided collective significance tests, and were adjusted for familial resemblance of resting pressure and heart rate as well as body mass index. These analyses showed significant parent-offspring and sibling associations in resting blood pressure and body mass index, which replicate those found in previous epidemiological investigations. The novel findings in this study were the sibling similarities in heart rate responses to mirror image tracing and in systolic blood pressure responses to isometric handgrip exercise. An analysis of a subset of the sample--only those nonmedicated parents compliant with instructions not to smoke or drink caffeinated or alcoholic beverages for 3 hr prior to testing and their children--showed a parent-offspring resemblance in systolic blood pressure responses to isometric exercise. This analysis, along with the significant sibling association from the full sample, suggests that systolic blood pressure responses to static exercise might aggregate in the family. The results are discussed in light of previous twin data. The relative paucity of significant parent-offspring associations of physiological parameters during serial subtraction and mirror image tracing tasks implies that non-familial influences are most important in determining cardiovascular responses to psychological stress.

Adolescent↗
PubMedDate not supplied

Do cardiovascular responses to laboratory stress relate to ambulatory blood pressure levels?: Yes, in some of the people, some of the time.

Because the correspondence between laboratory measures of blood pressure and heart rate responses to stress and ambulatory measures is less than optimal, this study tested two hypotheses: Are ambulatory measures of blood pressure elevated during periods of perceived stress, relative to no stress? Are ambulatory blood pressures elevated during perceived stress among those individuals who exhibit elevated blood pressure and heart rate responses to laboratory stress? These questions were addressed in a sample of employed, middle-aged men and premenopausal and postmenopausal women, who vary in reproductive hormone status, and in risk for coronary heart disease. All participants performed a series of laboratory studies while their physiological parameters were monitored and then wore an ambulatory blood pressure monitor for a day and a half. This monitor recorded blood pressure every half hour during the waking hours and at the same time the participants assessed their mood states. After excluding participants who reported no variability in stress levels, those who were cardiovascular reactors to a laboratory speech task exhibited elevated ambulatory blood pressure levels during periods of perceived stress. Furthermore, in general, periods of perceived stress were associated on a within subject basis with elevated ambulatory blood pressure. These results suggest that the correspondence between laboratory and field measures of blood pressure would be improved by taking into account the environmental circumstances during the ambulatory assessments and the person characteristics of reactor-nonreactor to laboratory stress.

Adult↗