Association of hypertension with beta2- and alpha2c10-adrenergic receptor genotype.

The adrenergic receptors have been implicated in the pathogenesis of essential hypertension. We hypothesized that hypertension is associated with variants at the beta2-adrenergic receptor locus and at one of the alpha2-adrenergic receptor loci. In unrelated individuals, we measured untreated blood pressure and characterized each subject as hypertensive or normotensive. We then used genomic DNA to identify beta2- and alpha2c10-adrenergic receptor restriction fragment length polymorphisms. In 175 subjects (49 percent with hypertension, 55 percent black), both hypertension and race were associated with genotype at the beta2 locus (chi2 for hypertension = 11, P = .004, chi2 for race = 8.8, P = .012). The association with hypertension persisted in each race group separately (blacks only: chi2 = 9.6, P = .008; whites only; chi2 = 14.2, P = .001). This association persisted in a logistic model that controlled for race (P = .01). Genotype was also significantly associated with baseline systolic, diastolic, and mean arterial blood pressures (P = .05, .01, and .02, respectively). These data suggest that the beta2-adrenergic receptor gene is a candidate gene for hypertension in blacks and whites. We also genotyped subjects at the alpha2-adrenergic receptor coded on chromosome 10. There was no association between hypertension and genotype at the alpah2c10 locus in the total group or in blacks, but there was significant association in whites (chi2 = 6.7, P = .03). These data suggest that the beta2- and alph2c10-adrenergic receptor genes may contribute, in a race-specific manner, to the inheritance of essential hypertension. Linkage studies in related individuals are needed to confirm these findings.

Job status and high-effort coping influence work blood pressure in women and blacks.

Work-related stress has been associated with an increased risk of hypertension and more severe cardiovascular problems in white men but has been less studied in women and black men. To determine whether the trait of high-effort coping (John Henryism) was related to higher blood pressure during work and laboratory challenges, we studied a biracial sample of 72 men and 71 women working full time outside the home who underwent ambulatory blood pressure monitoring for one 8-hour workday. This was followed by laboratory monitoring of blood pressure during resting baseline and five brief stressors. Women who were high-effort copers and had high status jobs had higher diastolic pressures at work and in the lab than other women; their pressure levels did not differ from those of men, but other women had lower pressures than men. In blacks, the same combination of high-effort coping plus high job status was similarly associated with high work and laboratory diastolic pressure, as well as higher work systolic pressure. The trait of high-effort coping was observed in the large majority (71%) of the women and blacks who had achieved high status jobs but was seen in a minority (36%) of white men with high status jobs and was unrelated to increased blood pressure in the latter group.

Right hemisphere speech perception revealed by amobarbital injection and electrical interference.

OBJECTIVE: To investigate the right hemispheric speech perception capabilities of an adult right-handed patient with seizures. METHODS: Consecutive, unilateral, intracarotid sodium amobarbital injections and left hemispheric electrical interference mapping were used to determine lateralization and localization of speech perception, measured as syllable discrimination. RESULTS: Syllable discrimination remained intact after left and right intracarotid sodium amobarbital injections. Language otherwise strongly lateralized to the left hemisphere. Despite evidence of bilateral speech perception capabilities, electrical interference testing in the left posterior temporal lobe impaired syllable discrimination. CONCLUSIONS: The results suggest a functionally symmetric, parallel system in the adult brain with preferential use of left hemispheric pathways for speech perception.

Frontal lobe volume in patients with Huntington's disease.

Neuropathologic and neuroimaging studies have suggested that frontal lobes are affected in Huntington's disease (HD), and that atrophy in this region may be associated with some of the cognitive impairment and clinical decline observed in patients with HD. We measured gray and white matter volumes within the frontal lobes on MRI for 20 patients with HD (10 mildly affected and 10 moderately affected) and 20 age- and sex-matched control subjects. We also correlated frontal lobe measurements with measures of symptom severity and cognitive function. Patients who were mildly affected had frontal lobe volumes (both gray and white matter) essentially identical to those of control subjects, despite clearly abnormal basal ganglia. Patients who were moderately affected demonstrated significant reductions in total frontal lobe volume (17%) and frontal white matter volume (28%). Frontal lobe white matter volume reductions, but not total frontal lobe volume reductions, were disproportionately greater than overall brain volume reductions (17%). Frontal lobe volume correlated with symptom severity and general cognitive function, but these correlations did not remain significant after taking into account total brain volume. We conclude that cognitive impairment and symptom severity are associated with frontal lobe atrophy, but this association is not specific to the frontal lobes. Frontal lobe atrophy (like total brain atrophy) occurs in later stages of increasing HD symptom severity and this atrophy primarily involves white matter.

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.

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.

Levels of analysis in health science. A framework for integrating sociobehavioral and biomedical research.

One of the principal goals of the Office of Behavioral and Social Sciences Research at the National Institutes of Health is to facilitate interdisciplinary research between social, behavioral, and biomedical scientists. The purpose of this paper is to provide a framework for such interdisciplinary health research. The essence of this framework is the concept of levels of analysis in the health sciences. These levels include the social/environment, behavioral/psychological, organ systems, cellular, and molecular. The interdependence of these five levels of analysis suggests that advances in the health sciences may be accelerated by a more integrated, multilevel approach to research. The principles of integrated, multilevel research are outlined, and examples of research that support this approach are presented. Finally, some of the activities of the Office of Behavioral and Social Sciences Research that will further interdisciplinary research across levels of analysis are summarized.

Reactivity research on sociodemographic groups: its value to psychophysiology and health psychology.

Research on sociodemographic group differences in cardiovascular reactivity has provided support for the potential importance of reactivity as marker-mediator of susceptibility to cardiovascular disease and has facilitated our understanding of the nature of reactivity itself. The article by Treiber et al. in this issue of Health Psychology exemplifies this area of reactivity research. Yet sociodemographic group differences in reactivity and other physiological processes are now in themselves in need of explanation. Thus, the principal scientific challenge facing researchers is the development of testable theoretical models that will facilitate the search for, and ultimate understanding of, the basis for these group differences. This process will not only clarify the determinants of sociodemographic group differences in psychophysiological functioning, but may significantly advance the general understanding of biopsychosocial interactions.

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.

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.

Macrosocial and environmental influences on minority health.

Ethnic minority populations show patterns of health, health care use, and mortality that differ from the overall U.S. population. Each of the broad groups of minorities (Asian Hispanic, Native, and African Americans) has a unique background of sociocultural factors that influence these patterns. Thus, the larger social environment for ethnic populations, including political, environmental, historical, and economic factors, is a major variable in possible health outcomes. The individual portions in this panel report of the conference seek to identify such factors for each ethnic group and to suggest those macrosocial influences that are most important for observed health effects.

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.

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.

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.

Racism as a stressor for African Americans. A biopsychosocial model.

Various authors have noted that interethnic group and intraethnic group racism are significant stressors for many African Americans. As such, intergroup and intragroup racism may play a role in the high rates of morbidity and mortality in this population. Yet, although scientific examinations of the effects of stress have proliferated, few researchers have explored the psychological, social, and physiological effects of perceived racism among African Americans. The purpose of this article was to outline a biopsychosocial model for perceived racism as a guide for future research. The first section of this article provides a brief overview of how racism has been conceptualized in the scientific literature. The second section reviews research exploring the existence of intergroup and intragroup racism. A contextual model for systematic studies of the biopsychosocial effects of perceived racism is then presented, along with recommendations for future research.

Integrating behavioral and social sciences research at the National Institutes of Health, U.S.A.

Readers of Social Science & Medicine may find it interesting to know that in 1993 the United States Congress established the Office of Behavioral and Social Sciences Research (OBSSR) at the National Institutes of Health (NIH) in the belief that scientific research on behavioral and social factors in order to facilitate a growth in this important area of research. As is discussed in this paper, the philosophy of the OBSSR is that, although discoveries in the behavioral and social sciences are as critical for health as those from the biomedical sciences, knowledge from both areas must ultimately be integrated. Such integration will accelerate our understanding and treatment of physical and mental illnesses in both the developed and the developing world. This paper briefly presents the scientific evidence supporting this philosophy, outlines the mandated responsibilities of the OBSSR, and discusses some of its current and planned activities.

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.

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.

Efficacy of racism-specific coping styles as predictors of cardiovascular functioning.

OBJECTIVE: This study examined the relationship between racism-specific coping strategies and cardiovascular responses to an ethnically relevant speaking task. METHODS: Fifty-seven African-American females participated in a speaking task during which they discussed their experiences with inter-ethnic group racism. Blood pressure and heart rate responses were measured during a pre-speech, speech, and recovery period. Racism-specific coping strategies were assessed with both the Perceived Racism Scale (PRS) and the Ways of Coping Scale-Revised (WCS-R). RESULTS: Multivariate regression analyses indicated that racism-specific coping strategies assessed via the PRS and WCS-R predicted blood pressure and heart rate changes. Passive coping strategies were generally associated with greater changes in systolic blood pressure, diastolic blood pressure, and heart rate during the pre-speech and speech periods, and with incomplete diastolic blood pressure recovery and heart rate recovery. Unexpectedly, the use of more active roping strategies was also associated with greater changes in diastolic blood pressure, and with incomplete heart rate recovery. CONCLUSION: This study provides preliminary empirical evidence that racism-specific coping styles may contribute to blood pressure and heart rate variability in African-American females.

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.