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Biomedical subjects

P A Obrist

Publications and source records attributed to P A Obrist.

At least 19 recordsLinked to original sources
PubMed1989

Psychologic distress as a predictor of mortality.

In a 12-year follow-up study of 610 persons (239 black and 371 white) in Evans County, Georgia, psychologic distress as measured by total score on the Health Opinion Survey, a 20-item questionnaire, was a predictor of mortality. The hazard ratio, comparing the 95th percentile score with the median, was 1.93 (97.5% confidence interval (CI) 1.42-2.62), controlling for age, race, and sex; there was no interaction with these variables. A purer measure of distress symptomatology, based on 18 of the questionnaire items, was also predictive of mortality. The hazard ratio was 1.94 (97.5% Cl 1.33-2.82), controlling for age, race, sex, and the item, "Do you have any sickness or illness problems at the present time?"; no interactions with the latter variables were found. This pattern was not affected in any major way by several modifications of the analyses: 1) controlling also for smoking, serum cholesterol, Quetelet index (weight (kg)/height (m)2), diastolic blood pressure, a social network index, and a social class index; 2) excluding persons with a diagnosis (in 1968) of chronic heart disease, angina pectoris, myocardial infarction, stroke, transient cerebral ischemic attach, or diabetes mellitus, or whose deaths were due to neoplastic disease; and 3) restricting the analyses to the last half of the follow-up period to explore the role of incipient or early physical illness in producing the association. With the restricted samples, confidence intervals included 1.00, which may be attributed to both the substantially smaller samples and the slightly reduced strength of the effect. The evidence is consistent with a causal role for psychologic distress, as measured by the Health Opinion Survey, in subsequent mortality rates.

Adult↗
PubMed1988

Motor preparation aspects of cardiovascular reactivity to psychological challenge.

Neural control of the circulation has evolved in such a way that behavioral responses to psychological stress may be accompanied by a dramatic activation of the cardiovascular system. This study was designed to address the hypothesis that such instances of cardiovascular mobilization reflect a functional motor preparation response. Twenty-four healthy young men participated in reaction time (RT) tasks which involved responding by squeezing a handgrip dynamometer. Motor preparation demands were manipulated by varying the temporal predictability of response requirements as well as the physical effort involved in responding, while controlling for other factors previously established to influence cardiovascular reactivity to psychologically challenging tasks. Physiological response measurements included heart rate, blood pressure and oxygen consumption. Increases in heart rate and systolic blood pressure during the RT tasks showed a general pattern which was consistent with the predictions of the motor preparation hypothesis, with the greatest elevations occurring in association with low temporal predictability and high physical effort. The possibility is discussed that factors such as incentives and elements of uncertainty may influence cardiovascular reactivity by accentuating behavioral arousal, of which motor preparation may be an inextricable component.

Adaptation, Psychological↗
PubMed1987

Stability of cardiovascular reactivity to laboratory stressors: a 2 1/2 yr follow-up.

The temporal stability of cardiovascular reactivity to laboratory stressors over a 2 1/2 yr period was studied. Subjects who had earlier received a cold pressor and a shock avoidance reaction time task were brought back for retesting using almost identical tasks. Cardiovascular variables that were common to both sessions included heart rate, systolic and diastolic blood pressure, and pre-ejection period. Correlations were computed to examine the association of responses across both sessions for the four cardiovascular variables during rest and the two tasks. Correlations of both heart rate and systolic blood pressure were high for all tasks and rest, whereas inconsistent correlations were found for diastolic pressure and pre-ejection period. Inconsistencies in diastolic pressure are speculated to be due to individual differences in beta-adrenergic response, whereas lack of consistent pre-ejection period associations may be due to differences in methodology. The results generally support the assumption of stability of cardiovascular reactivity.

Adult↗
PubMed1987

Effects of race and marginally elevated blood pressure on responses to stress.

A total of 228 men, aged 18 to 22 years (109 black and 119 white), underwent monitoring of heart rate (HR) and systolic (SBP) and diastolic blood pressure (DBP) responses during several stressor conditions and a 30-minute posttask rest period. Stressors included the cold pressor test and three reaction-time tasks: noncompetitive, competitive, and competitive plus money incentive. Substantial within-subject variations in blood pressure and heart rate were induced, varying from 119/70 to 148/94 mm Hg and from 63 to 91 beats/min on the average. Men (25 black and 39 white) with marginal SBP elevations during initial casual determinations had higher SBP under all conditions compared with men whose casual SBP levels were normal, and they also showed greater elevations over baseline levels in heart rate, SBP, and DBP during the stressors and the initial casual determination. Black and white subjects did not differ in their blood pressures at baseline or during the initial casual determinations, although blacks had slightly lower heart rates. Blacks did show greater SBP elevations over baseline levels than whites during the stressors, primarily because the blacks with marginally elevated SBP showed substantially greater stress-induced increases than whites with marginally elevated SBP. This enhanced pressor response to stress in blacks with marginal blood pressure elevations may be due to higher vascular resistance during enhanced sympathetic activity and could contribute to the higher incidence of hypertension among blacks.

Adult↗
PubMed1984

Vasopressin and urine flow rate responses to stress in conscious dogs.

Behavioral stress increases arterial pressure while decreasing urine flow rate; the urine flow rate response can be abolished by surgical renal denervation. In this study, the effects of infusion of alpha-adrenoceptor antagonists (intravenous phenoxybenzamine or prazosin) on the antidiuretic and plasma vasopressin responses to stress were examined. Without alpha-adrenoceptor blockade, 20 min of stress increased arterial pressure and decreased urine flow rate, but no change in urine osmolality or plasma vasopressin concentration occurred. Arterial pressure and urine flow rate returned to base-line level during a 20-min recovery period. With alpha-adrenoceptor blockade, which prevented the arterial pressure response to stress, urine flow rate still decreased during stress, but urine osmolality and plasma vasopressin concentration increased. The decrease in urine flow rate and increase in urine osmolality and plasma vasopressin concentration persisted into the first 20-min recovery period but returned to base-line level during a second 20-min recovery period. We conclude that the antidiuretic response to behavioral stress in conscious dogs with saline infusion alone is not mediated via a change in vasopressin release. In contrast, the antidiuretic response to behavioral stress with alpha-adrenoceptor antagonist infusion may be mediated via an increased release of vasopressin.

Animals↗
PubMed1983

Psychological stress induces sodium and fluid retention in men at high risk for hypertension.

Exposure to competitive mental tasks significantly reduced the urinary sodium and fluid excreted by young men with one or two hypertensive parents or with borderline hypertension. In this high-risk group, the degree of retention was directly related to the magnitude of heart rate increase during stress, suggesting common mediation by way of the sympathetic nervous system. Thus, psychological stress appears to induce changes in renal excretory functions that may play a critical role in long-term blood pressure regulation.

Adolescent↗