Biomedical subjects

S S Girdler

Publications and source records attributed to S S Girdler.

29 records · Page 2Linked to original sources

PubMed1994

Hemodynamic stress responses in men and women examined as a function of female menstrual cycle phase.

Fifteen men and 11 normally ovulating women were each tested twice for cardiovascular stress reactivity, cognitive/behavioral performance, and mood during a variety of stressors. Each women was tested during both the follicular and luteal phase of her menstrual cycle, with men matched for number of days between testing. Although the genders did not differ in blood pressure reactivity during either phase of the cycle, during both phases of the menstrual cycle women exhibited greater heart rate reactivity and tended towards greater cardiac index increases, greater pre-ejection period decreases, and lesser vascular tone relative to men. Additionally, the menstrual cycle was observed to influence gender differences in stroke volume index responses. Specifically, stroke volume index responses for women were significantly greater in their luteal versus follicular phase resulting in a marginally significant pattern whereby women's stroke volume index responses were greater than men's luteally but less than men's follicularly. Men and women also differed in cognitive performance and mood assessment during the tasks, but the majority of these differences were unaffected by the menstrual cycle.

Adult↗

PubMed1994

Comparison of cardiac versus vascular reactors and ethnic groups in plasma epinephrine and norepinephrine responses to stress.

This study examined differences in plasma epinephrine (EPI) and norepinephrine (NOREPI) responses to stressors in 67 healthy African-American and Caucasian American men and women of the ages 18 to 49. Subjects were divided into three groups: (a) those who showed high blood pressure (BPI responses to stress associated with consistently high cardiac output (CO) increases with no substantial increases in total peripheral resistance (TPR), labeled cardiac reactors: (b) those with equally high BP increases associated with consistently higher TPR increases and lesser CO increases. labeled vascular reactors; (c) those who showed mixed hemodynamic responses or were low BP reactors. Ethnic and gender group differences in EPI and NOREPI responses were also examined. Cardiac reactors, vascular reactors and mixed + low reactors did not differ in EPI or NOREPI levels at baseline. During stressors, cardiac reactors showed greater increases in plasma EPI than vascular reactors or others during math, reaction time, and passive and active speech tasks: they also showed a weak trend toward greater NOREPI increases during these challenges as well. No differences were seen during the cold pressor: this stressor evoked the least change in EPI of all tasks, whereas the active speech elicited the greatest increases in both EPI and NOREPI of all tasks. Vascular reactors did not differ from mixed + low reactors in EPI or NOREPI reactivity, and men and women did not differ in EPI or NOREPI reactivity to any task. In contrast, Black subjects showed greater increases in NOREPI levels across all stressors compared to White subjects. These findings have implications for investigations of the role of sympathetic nervous system activity in the pathogenesis of hypertension in both African-American and Caucasian American populations.

Journal Article↗

PubMed1993

Peripheral adrenergic receptor contributions to cardiovascular reactivity: influence of race and gender.

Ten White males, ten Black males, ten White females, and seven Black females (aged 22-48 yr) were exposed to a competitive reaction time task (enhancing beta-receptor activity), the forehead cold pressor (enhancing alpha-receptor activity), and a speech task on four separate occasions: twice under a saline placebo condition, once under a beta-blockade condition using i.v. propranolol, and once under a combined beta- and alpha-blockade condition using both i.v. propranolol and i.v. phentolamine. Order of placebo session and blockade session was counterbalanced across each race/gender group. Beta-blockade abolished the greater heart rate, cardiac index, and stroke volume index responses, and the lesser vascular tone seen under placebo in White vs. Black males. No differences between White and Black women were seen with or without beta-blockade. Gender differences in beta-receptor contribution to stress responses were restricted to the White subjects. Beta-blockade abolished the greater stroke volume index responses and less vascular tone observed in White males vs. White females. Although alpha-receptor blockade significantly decreased vascular resistance in each race/gender group, it did not differentially affect any of the subgroups. These data suggest that race and gender differences in cardiovascular stress responses of normotensive individuals are at least partly a function of differential beta-receptor activity/sensitivity. No clear support for differences in alpha-receptor activity/sensitivity was obtained.

Adult↗

PubMed1993

Menstrual cycle and premenstrual syndrome: modifiers of cardiovascular reactivity in women.

Fifteen women prospectively diagnosed with PMS and 15 non-PMS women were each tested twice for cardiovascular stress reactivity and behavioral performance, once during the follicular phase and once during the luteal phase of their cycle. Although blood pressure and heart rate responses to stress did not differ across the menstrual cycle in either group of women, for the non-PMS women, differences in hemodynamic responses were observed across the 2 phases. The luteal phase was associated with greater stroke volume responses and lesser vascular tone. For the PMS women, none of their cardiovascular measures differed across their cycle. Instead, these women showed significantly attenuated blood pressure and heart rate responses compared with non-PMS women, irrespective of cycle phase.

Adult↗

PubMed1992

Reactivity to stress and psychological adjustment in adults with pituitary insufficiency.

OBJECTIVE: Hypopituitary adults who were affected during childhood have a below-average rate of marriage, a rate of unemployment that exceeds national norms, and often indicate dissatisfaction with their life circumstances. We undertook the present study to determine the effects of short stature versus those of pituitary hormone deficiency. DESIGN AND PATIENTS: We compared hypopituitary adults (n = 25) with normal short adults (n = 25) who were matched for height, sex, age and socioeconomic status. MEASUREMENTS: In these two groups of subjects, we compared the physiological responses to a simulated social stressor, a public speaking task, and we measured the psychometric attributes that are indicators of social assertiveness and extraversion. RESULTS: Before, during and after the stress of public speaking, patients with multiple pituitary hormone deficiencies (n = 20) had lower mean systolic and diastolic blood pressures than controls, while patients with isolated growth hormone deficiency (n = 5) were equivalent to controls. The reactivity to stress, assessed using delta scores based on changes in blood pressure and heart rate, was also decreased in multiple hormone deficient patients. Psychometric test results indicated that patients with multiple hormone deficiencies showed lower openness, lower assertiveness, greater neuroticism and a tendency towards less extraversion than did controls. The responses of patients with isolated GH deficiency on the psychometric tests were not statistically different from controls, but the number of subjects in this group (n = 5) was too small to draw conclusions. CONCLUSIONS: The impaired cardiovascular responses to stress in patients with multiple hormone deficiencies, compared to short control subjects and to patients with GH deficiency leads us to conclude that factors other than stature and GH are responsible for these observations. The differences might be related to insufficiency of catecholamines or cortisol in the patients with multiple hormone deficiencies. These hormonal deficiencies might also account for the socially inhibited behaviour of these patients. Our results suggest that more attention needs to be directed at preparing hypopituitary patients for the challenges of adulthood. Also, these patients may be helped by more intensive efforts at hormonal replacement in adulthood.

Adolescent↗

PubMed1990

Cardiovascular responses to behavioral stressors: laboratory-field generalization and inter-task consistency.

Blood pressure and heart rate responses were monitored while 30 medical, dental or graduate students completed four laboratory tasks. On a second day, subjects wore an ambulatory blood pressure monitor, and during this day they completed the real-world challenge of presenting their research in front of a small audience. Heart rate and blood pressures correlated significantly between all four laboratory tasks for both absolute levels and reactivity scores (calculated as task level minus pre-task baseline level). However, while heart rate and blood pressure absolute levels for each task correlated significantly with those attained during the real-world stressor, correlation coefficients obtained when similarly comparing reactivity scores were uniformly non-significant. Laboratory-field generalization was thus evident only for absolute values. Consideration was then given to the fact that the laboratory tasks were undertaken in a seated position, while subjects stood during the real-world task. Activity diaries completed by subjects during the time they wore the ambulatory monitor were examined to search for readings that could be regarded as standing baselines. Such values were obtained for 12 of the subjects. Real-world reactivity scores were recalculated using these standing baselines, and compared again with reactivity scores during the laboratory tasks. Marked increases in correlation coefficients were obtained for systolic and diastolic pressure, but not for heart rate.

Adult↗

PubMedDate not supplied

Gender differences in blood pressure control during a variety of behavioral stressors.

This study assessed gender differences in hemodynamic response patterns to behavioral stressors. In addition, the extent to which gender differences in cardiovascular reactivity were a function of the type of challenge was determined by employing tasks relying on stereotypically male areas of competence and a task relying on stereotypically female areas of competence. Sixteen female and 15 male graduate, medical or dental students were exposed to two speech tasks and two math tasks. While there were no significant differences in blood pressure reactivity between the genders, females exhibited significantly greater cardiac output increases across all tasks than males, while males tended to respond with greater increases in total peripheral resistance compared with females. Furthermore, during two of the tasks, significantly more females were classified as myocardial hyperreactors (based on increases in cardiac output), while significantly more males were vascular hyperreactors (based on increases in total peripheral resistance). A post hoc analysis also indicated an apparent association between oral contraceptive use and higher cardiovascular reactivity among the females tested. This association may have been a consequence of the decision to test all women during days 10 to 14 of the menstrual cycle when reactivity in women not using oral contraceptives may be suppressed.

Adult↗

PubMedDate not supplied

Smoking status and nicotine administration differentially modify hemodynamic stress reactivity in men and women.

OBJECTIVES: To investigate the impact of cigarette smoking and oral contraceptive (OC) use on hemodynamic stress responses of women. Also, to examine gender differences in stress reactivity as a function of smoking status and acute nicotine administration. METHODS: Thirty men and 46 women, differing in smoking status and OC use, were tested for cardiovascular stress responses to a variety of behavioral and physical stressors. Each was tested twice, once under a transdermal nicotine patch condition and once under a placebo patch condition. Impedance cardiography was used to estimate hemodynamic reactivity noninvasively. RESULTS: In response to behavioral stressors, women smokers, irrespective of OC use or nicotine vs placebo, demonstrated significantly blunted cardiac output and heart rate reactivity to stressors, and showed significantly greater estimated total peripheral resistance (TPR) under stress relative to women nonsmokers. There were no differences in hemodynamic stress reactivity between men smokers and nonsmokers. The only significant effect involving nicotine administration on stress reactivity was seen in men where, regardless of smoking status, nicotine increased heart rate reactivity to all stressors relative to placebo responses. CONCLUSIONS: Results suggest that cigarette smoking may act differently in men and women to increase risk for cardiovascular disease (CVD). For men, nicotine may exert pathogenic influences via increasing the magnitude of heart rate reactivity to stressors. For women, however, smoking seems to have deleterious effects on hemodynamic stress reactivity patterns, reducing myocardial but increasing TPR contributions to blood pressure responses.

Administration, Cutaneous↗

PubMedDate not supplied

Ischemic but not thermal pain sensitivity varies across the menstrual cycle.

OBJECTIVE AND METHOD: Findings from both animal and human research suggest that pain sensitivity changes across the menstrual cycle; however, among humans the nature of these menstrual cycle effects remains unclear. The present study used a repeated-measures design to evaluate changes in thermal and ischemic pain responses during three phases of the menstrual cycle, midfollicular (postmenstrual), ovulatory, and mid-to-late luteal (premenstrual), in 11 healthy women. The cycle phase during which subjects began their participation was determined randomly. Plasma levels of estrogen, progesterone, luteinizing hormone (LH), testosterone, and beta-endorphin were determined at each experimental session. Participants also completed a daily diary of physical and emotional symptoms for two complete menstrual cycles before the experimental sessions. RESULTS: The results indicated that women showed less ischemic pain sensitivity during the midfollicular compared with the ovulatory and mid-to-late luteal phases, but thermal pain responses did not vary significantly across menstrual cycle phases. Physical and emotional symptoms were minimal and did not change significantly across the menstrual cycle. CONCLUSIONS: These findings indicate greater ischemic but not thermal pain sensitivity among women after the midcycle LH surge. The practical relevance and potential mechanisms of these findings are discussed.

Adult↗

PubMedDate not supplied

Blood pressure-related hypoalgesia in bulimia nervosa.

OBJECTIVE: This study examined pain sensitivity and its relationship to arterial blood pressure in bulimia nervosa (BN). METHODS: Fourteen women who met Diagnostic and Statistical Manual of Mental Disorders, 4th Edition, criteria for BN, purging subtype, and 14 controls were tested for ischemic pain sensitivity after an extended baseline period. Blood pressure, cardiac output, stroke volume, and total peripheral resistance were assessed during baseline, during ischemic pain testing, and at the point of voluntary tolerance. RESULTS: Women with BN had significantly greater ischemic pain tolerance than controls. Additionally, only for BN women was blood pressure related to pain sensitivity. Systolic blood pressure during the pain procedure and at the point of tolerance was positively related to pain threshold and tolerance times and negatively related to rated unpleasantness of pain in BN, whereas no relationships involving blood pressure and pain sensitivity were observed in controls. CONCLUSIONS: These results may have implications for maladaptive changes in central pain-cardiovascular regulatory systems for women with BN.

Adult↗

PubMedDate not supplied

Women with eating disorder tendencies display altered cardiovascular, neuroendocrine, and psychosocial profiles.

OBJECTIVE: Cardiovascular, neuroendocrine, and psychosocial profiles were investigated in women with eating disorder tendencies, but who had never met clinical criteria for an eating disorder, and in healthy controls. METHODS: Twenty-six women who scored in the highest distribution of the Eating Disorder Inventory bulimia subscale (HEDI women) and 27 women who scored in the lowest distribution (LEDI women) completed psychosocial questionnaires, underwent a speech reactivity task for measures of blood pressure and heart rate reactivity, and also underwent 24-hour ambulatory blood pressure monitoring and urinary neuroendocrine collection. RESULTS: The HEDI women exhibited increased blood pressure and heart rate reactivity to the speech task and increased 24-hour urinary cortisol, but decreased 24-hour urinary norepinephrine compared with LEDI women. There were no overall group differences in 24-hour ambulatory blood pressure levels, but negative mood and tension were associated with greater systolic blood pressures for all women. Finally, HEDI women reported greater depressive symptoms and anxiety, lower self-esteem and sense of mastery, less social support, poor coping skills, and greater emotional impact of daily stressors relative to LEDI women. CONCLUSIONS: These results indicate that the same pattern of neuroendocrine and psychosocial profiles seen in prior studies of bulimia nervosa are also present in women with eating disorder tendencies.

Adolescent↗