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Biomedical subjects

N B Anderson

Publications and source records attributed to N B Anderson.

At least 37 records · Page 2Linked to original sources

Accentuated vagal antagonism of beta-adrenergic effects on ventricular repolarization. Evidence of weaker antagonism in hostile type A men.

BACKGROUND: Prior research has suggested a weaker parasympathetic antagonism of sympathetic effects on the heart in type A (coronary-prone) men. To confirm this phenomenon and extend our understanding of it, we investigated the effects of prior muscarinic blockade on the electrocardiogram T wave and other cardiovascular and neuroendocrine responses to isoproterenol in type A and type B (non-coronary-prone) men. METHODS AND RESULTS: Responses to two 5-minute intravenous isoproterenol infusions (0.01 micrograms/kg/min and 0.02 micrograms/kg/min) were evaluated in six type A and six type B men after pretreatment with either dextrose placebo or atropine (1.2 mg). Atropine significantly potentiated T wave attenuation in the recovery period after isoproterenol infusion (0.30 +/- 0.07 mV) compared with placebo (0.54 +/- 0.09 mV, p less than 0.001). Atropine also potentiated the heart rate increase to isoproterenol (39 +/- 3 beats per minute versus 20 +/- 2 beats per minute after placebo). Atropine enhanced decreases in systolic, diastolic, and mean arterial pressures as well as pulse pressure to isoproterenol. Atropine enhancement of many of these responses was increased among subjects with high scores on various hostility/anger scales. Isoproterenol alone produced greater T wave attenuation in type A than in type B men. However, atropine enhancement of T wave attenuation and blood pressure falls by isoproterenol was present only in type B men. CONCLUSIONS: These findings indicate that there is accentuated parasympathetic antagonism of T wave attenuation and blood pressure responses induced by beta-adrenergic stimulation. Relative weakness of this antagonism of sympathetic effects on the heart in hostile type A individuals may contribute to their higher coronary disease risk.

Adult↗

Hostility patterns and health implications: correlates of Cook-Medley Hostility Scale scores in a national survey.

Correlated Cook-Medley Hostility Scale (Ho) scores with sociodemographic variables in a national survey of 2,536 adults. Multiple regression models revealed that Ho scores were associated with race (p less than .0001), years of education (p less than .001), sex (p less than .001), occupation (p = .0002), and income (p = .0025). Higher scores were found in non-Whites, men, and those of lower socioeconomic status. There was a Race x Income interaction (p less than .005), such that the greatest Ho score differences between the races occurred among those with the lowest incomes. Age was related to Ho scores in a curvilinear fashion: higher scores in the youngest and oldest age groups than in the middle-aged groups (p = .025). Marital status was unrelated to Ho scores. These patterns of hostility are similar to the patterns of health indicators in the population. Because hostility has been found to be associated with adverse health outcomes, hostility may account for some of the demographic variations in health status. However, it is argued that research must first establish the generality of the hostility-health relationship across subgroups of the population.

Adolescent↗

Autonomic reactivity and hypertension in blacks: a review and proposed model.

In summary, according to the proposed model, race is viewed as a sociocultural designation that denotes differential exposure to chronic social stressors. It is proposed that black Americans are exposed to significantly more chronic social stressors than are white Americans. Many of these chronic social stressors have been associated with hypertension prevalence in epidemiological studies. Furthermore, chronic stress has been shown to augment cardiovascular reactivity to acute stress in both animals and humans, and to increase sodium retention in spontaneously hypertensive rats. Acute stress has also been demonstrated to increase sodium retention in humans. The essential element of our model is that chronic social stressors that are represented more within the black American population due to historical factors are related to an increase in sodium sensitivity and retention. This altered sodium metabolism may be further augmented by biological, behavioral, and psychological risk factors for hypertension and modulated by stress coping resources. It is hoped that this model will serve as a stimulus for further research on the biopsychosocial aspects of autonomic reactivity and hypertension in blacks.

Black or African American↗

Patterns of cardiovascular responses to stress as a function of race and parental hypertension in men.

This study investigated cardiovascular responses to two stressors known to elicit either beta-adrenergic (mental arithmetic) or alpha-adrenergic (forehead cold pressor) reactivity in Black and White men. Participants in each group were selected for presence or absence of parental hypertension. Based on previous research, Blacks were expected to show smaller cardiovascular responses to the beta-adrenergic mental arithmetic task and greater responses to the alpha-adrenergic cold pressor relative to the Whites. Systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate, forearm blood flow, and forearm vascular resistance were assessed during a resting baseline, a prestress period, and during and after each experimental procedure. Unlike previous findings, no significant racial differences in cardiovascular responses were found during either task. However, Black participants had significantly higher SBP and DBP levels throughout the cold pressor periods. Parental history did not significantly influence cardiovascular responses in either group. The results are discussed in relation to previous research on racial differences in stress reactivity and their implications for future research.

Adrenergic Fibers↗

Racial differences in stress-induced cardiovascular reactivity and hypertension: current status and substantive issues.

Essential hypertension is perhaps the number-one health problem of Black Americans. Research has indicated that stress-induced cardiovascular hyperreactivity may be a significant contributor to essential hypertension. The high prevalence of hypertension among Blacks suggests that this group, in comparison with Whites, may be particularly susceptible to cardiovascular hyperreactivity. The first portion of this article reviews research to date that has examined racial differences in resting and stressor-induced cardiovascular activity. The second half of this article overviews some critical methodological and conceptual issues involved in the study of racial differences in reactivity. These issues include the effects of Black-White differences in plasma renin levels and sodium excretion, the effects of experimenter race, and differences in perceptions of the laboratory environment. Additionally, the issue of racial group classification and the implications this has for interpreting Black-White differences in reactivity is discussed. Two perspectives on racial group classification, the genetic and the sociocultural, are addressed in some detail, and the relevance of each to research on racial differences in stress reactivity is presented.

Black or African American↗

Race, parental history of hypertension, and patterns of cardiovascular reactivity in women.

This study examined the interaction of race and parental history of hypertension on patterns of cardiovascular responses among women. Two stressors were used that produce different patterns of cardiovascular reactivity: mental arithmetic, primarily a beta-adrenergic stimulus, and the cold face stimulus, which evokes alpha-adrenergic (i.e. vascular) activity. Systolic and diastolic blood pressure, heart rate, forearm blood flow, and forearm vascular resistance were assessed before, during, and after arithmetic and cold face stimulus. Both tasks produced the expected patterns of cardiovascular adjustment, although no Black-White differences occurred during arithmetic. However, Black subjects did show a slower recovery of diastolic blood pressure following arithmetic. The cold face stimulus produced significantly greater changes in systolic blood pressure in the Black than in the White women. Parental history of hypertension did not relate significantly to reactivity. The results provide limited support for the idea that Black females exhibit a greater pressor response than White females to a stimulus that produces primarily vascular rather than cardiac changes. These findings are discussed in relation to previous findings with males and with respect to their implications for the role of reactivity in Black-White differences in hypertension prevalence.

Adolescent↗

Beta and alpha adrenergic reactivity elicitable stress study with special reference of electrocardiographic T-wave amplitude.

Twenty-six healthy young Caucasian males were defined into high hostile (Hi-Ho) group and low hostile (Lo-Ho) group assessed by Cook-Madley's Hostility (Ho) scale. Mental arithmetic task (MA) and forehead cold stimulus task (FCS) were loaded to both Hi-Ho and Lo-Ho groups. Electrocardiographic T-wave amplitude (TWA), heart rate (HR) and coefficient of variance of 100 R-R intervals (CVR-R) were measured continuously during MA and FCS task periods. Greater TWA attenuation was found in Hi-Ho group (p less than 0.05). Although no significant intergroup difference was represented in HR and CVR-R, HR increased significantly (p less than 0.01) in whole subjects and CVR-R was tend to be suppressed during MA period. In addition, comparison of these physiological responses were performed between Type-A and Type-B groups classified by Jenkins' Activity Survey Form-T (JAS-T). There was no significant difference in reactivity of TWA, HR and CVR-R to both two tasks between high and low Type-A scored groups. Previous data suggested that the TWA reactivity in Hi-Ho subjects to cognitive stress showed similar pattern in Type-A individuals. However, autonomic nervous interaction could not be clarified in Hi-Ho subjects. The differentiation of method for assessment of behavioral pattern was also discussed.

Adolescent↗

Hypertension in blacks: psychosocial and biological perspectives.

The extraordinarily high rate of hypertension in blacks remains a significant public health issue in most industrialized societies. Research has focused on the investigation of racial differences in biological, nutritional, behavioural and psychological, and social factors in an effort to identify the causes of this high morbidity rate. Thus far, research suggests important racial differences in renal functioning, particularly in sodium metabolism and plasma renin activity, as well as potassium intake and sodium:potassium ratio. Behavioral factors such as anger-coping style and John Henryism, and social factors such as socioeconomic status, socioecological stress, social support, urban-rural residence, and family interaction patterns have also been identified as potential contributors. Finally, emerging research paradigms such as laboratory stress reactivity and 24-h ambulatory monitoring of blood pressure may provide promising leads about the interaction between these effects and hypertension in black populations.

Black or African American↗

Racial differences in cardiovascular reactivity to mental arithmetic.

One hypothesized mechanism for the higher rates and greater severity of essential hypertension among blacks is that this group is particularly susceptible to stress-induced beta-adrenergically mediated cardiovascular hyperreactivity. In this study, we compared the cardiovascular responses to mental arithmetic in 20 white and 17 black, young, normotensive males. Contrary to expectations, the black subjects exhibited significantly smaller changes in heart rate, and systolic and diastolic blood pressure. These findings suggest that cardiovascular reactivity to a mental stressor known to produce beta-adrenergically mediated responses may be lower in some normotensive blacks compared to their white counterparts.

Black or African American↗

Physiological responses to catecholamine infusions in type A and type B men.

To determine whether there are basic biological differences between Type A and Type B men, we compared hemodynamic, electrophysiologic and neuroendocrine responses to equipotent doses of isoproterenol (ISO) and norepinephrine (NE) in 10 Type A and 10 Type B men ages 18 to 29. Results showed equal hemodynamic and neuroendocrine responses to graded ISO doses in Type A and Type B individuals. In contrast, Type A men showed a more prolonged decrease in electrocardiographic T-wave amplitude (TWA) than did Type B men. Post hoc analyses of the correlates of TWA recovery during high-dose ISO infusion provide preliminary evidence for a more robust parasympathetic antagonism of sympathetic nervous system effects in Type B men, especially those with low scores on the Cook-Medley Ho scale. These findings suggest that, in addition to cognitively mediated increases in sympathetic nervous system reactivity, Type As may also be placed at increased risk of developing coronary heart disease by reduced levels of parasympathetic antagonism of sympathetic effects.

Adolescent↗

Parental history of hypertension and cardiovascular responses to behavioral stress in young black women.

Beta-adrenergic sympathetic nervous system (SNS) hyperresponsivity to behavioral stress may play a role in the onset of sustained high blood pressure--particularly in persons with a parental history of hypertension. Although hypertension is extremely prevalent among blacks, the association between parental history of hypertension and cardiovascular hyperresponsivity has not been explored in this group. The present study examined the influence of parental history of hypertension on cardiovascular stress reactivity in a group of young black females. Contrary to previous findings with whites, black subjects with a parental history of hypertension exhibited significantly smaller systolic blood pressure and forearm blood flow increases, and moderately smaller diastolic blood pressure increases to the task. Parental history subjects also exhibited slower heart rates throughout each experimental condition. The results suggest that blacks at risk from hypertension may not exhibit the beta-adrenergic hyperresponsivity to behavioral stress observed in whites. These results may suggest that beta-adrenergically mediated hyperresponsivity may be less involved in the development of hypertension among blacks.

Adult↗

Models of personality and disease: an interactional approach to type A behavior and cardiovascular risk.

Type A behavior has been established as a risk factor for coronary heart disease. Enhanced cardiovascular and neuroendocrine responsiveness to stressors has been suggested as a pathophysiological link between the behavior pattern and disease. The present article describes a model that places this link in an interactional context. Specifically, it is hypothesized that via cognitive and overt behaviors, Type As construct a subjective and objective environment rich in those classes of stimuli known to elicit enhanced physiological reactivity. This approach differs from previous ones by emphasizing that the Type A pattern represents an ongoing process of challenge and demand engendering behavior. That is, Type A persons do not simply respond to challenges and demands; they seek and create them through their cognitions and actions. This constructed environment also elicits and maintains further Type A behavior. The present view of Type A behavior as a challenge and demand engendering style is contrasted with other conceptual approaches, and implications are discussed.

Achievement↗

Type A behavior, family history of hypertension, and cardiovascular responsivity among black women.

The purpose of this study was to determine the effects of Type A behavior and family history of hypertension on cardiovascular reactivity to mental stress in a group of employed black women. Measures of heart rate and of systolic blood pressure (SBP) and diastolic blood pressure (DBP) were taken at rest, during a mental arithmetic task, and during the Type A Structured Interview (SI). Results indicated that the Type A behavior pattern was associated with SBP and DBP hyperresponsivity during the SI but not during mental arithmetic. Additionally, certain speech components of the Type A pattern, as well as features of the potential-for-hostility component, were also related to cardiovascular responses during the SI. Family history of hypertension did not influence the cardiovascular parameters either alone or in combination with Type A behavior. The results suggest that many of the cardiovascular response characteristics of the Type A pattern that have been observed in predominantly white samples also hold true for blacks. Replication of these findings with other subgroups of blacks, such as young females and middle-aged males, will help document the generality of these findings within the black population.

Adult↗

The effect of coping statements on progress through a desensitization hierarchy.

The effect of "coping statements" on the rapidity of progress through desensitization hierarchies was examined in several cases of clinically significant anxiety-based disorders. Using a series of single-case experimental designs (relying heavily on an alternating treatments element), it was shown that (a) coping statements decrease the reported anxiety shown in desensitization, (b) these statements seem to produce greater behavioral gains outside the treatment sessions per unit of treatment time, (c) the coping statements gradually begin to generalize across stimuli and (d) their effects go beyond those due merely to distraction, competing behaviors, or general expectations. The present methodology may comprise an alternative method, more compatible with ongoing clinical work, for the investigation of cognitive treatments.

Adaptation, Psychological↗