Hypertension In Blacks Research Articles

Studies of red cell cation transport in white and black essential hypertensives

Summary It has been reported previously in white patients with essential hypertension that red cell sodium pump activity as measured by ouabain-sensitive uptake of the potassium analogue 86Rb from a potassium-free medium, is very significantly greater than in white controls. In a further study of black (West Indian) subjects reported here no similar abnormality was present in black hypertensives when compared with black normotensive individuals. Red cell rubidium uptake was significantly lower in normotensive blacks than in normotensive whites although sodium pump activity was the same. These results may be relevant to observed racial differences in sodium handling and in the pathophysiology of essential hypertension.

Histocompatibility antigens in black patients with essential hypertension.

Essential hypertension is a common disorder with potentially life-threatening sequelae. Hypertension among black persons may have characteristics different from hypertension among white persons. It has been estimated that up to 60% of population variance in blood pressure may be attributable to genetic differences. We studied the distribution of HLA antigens in 100 black hypertensives and 100 normotensive controls. Hypertension was not significantly associated with any of the 25 HLA antigens identified. We conclude that HLA-A and HLA-B locus antigens are not associated with essential hypertension in the black patient.

Hypertension in Blacks and Whites

Hypertension in Blacks and Whites

Racial differences in blood pressure in evans county, Georgia: Relationship to sodium and potassium intake and plasma renin activity

To investigate the hypothesis that the higher prevalence of hypertension in blacks may be related to a greater dietary intake of sodium, we studied the relationship between race, blood pressure, estimates of dietary sodium and potassium intake, and plasma renin activity (PRA), in two population samples from Evans County, Georgia. In the first random sample obtained in 1961, dietary electrolyte intake was estimated by duplicate dietary collections and simultaneous 24-hr urine collections. In the second sample obtained in 1968, a single-morning urine specimen was obtained and PRA was measured in each subject. The data demonstrate that blacks and whites ingested similar quantities of sodium, but that the dietary potassium intake of blacks was consistently less than that of whites. Blacks had higher blood pressures than whites and a greater prevalence of individuals with diastolic blood pressures >90 mmHg. PRA was inversely correlated with age, blood pressure and estimates of sodium intake. The higher blood pressures and higher prevalence of hypertension in blacks does not appear to be a function of a greater dietary sodium intake in blacks. However, an increased susceptibility to the hypertensinogenic effects of sodium in blacks remains a possibility.

Pathophysiology of hypertension in blacks and whites. A review of the basis of racial blood pressure differences.

Differences in blood pressure between blacks and whites in the United States are now well documented. The causes of these differences remain speculative. Genetic factors, personal characteristics, renal physiology, endocrine factors, autonomic nervous system function, cardiac function and various environmental factors are examined in the present review as potential determinants of racial blood pressure differences. Racial differences in renal physiology and environmental influences such as socioeconomic status seem to be likely candidates for important contributions to blood pressure differences. Further research aimed specifically at black-white blood pressure differences is of great importance to a fundamental understanding of the etiology and prevention of essential hypertension.

Essential hypertension in blacks and whites. Hemodynamic findings and fluid volume state : Messerli FH, DeCarvalho JGR, Christie B, Frohlich ED: Am J Med 67: 27–31, 1979

Essential hypertension in blacks and whites. Hemodynamic findings and fluid volume state : Messerli FH, DeCarvalho JGR, Christie B, Frohlich ED: Am J Med 67: 27–31, 1979

Fluid partition and cardiac output in volume-depleted Goldblatt hypertensive rats.

ARTICLESFluid partition and cardiac output in volume-depleted Goldblatt hypertensive ratsN. C. Trippodo, G. M. Walsh, R. A. Ferrone, and R. C. DuganN. C. Trippodo, G. M. Walsh, R. A. Ferrone, and R. C. DuganPublished Online:01 Jul 1979https://doi.org/10.1152/ajpheart.1979.237.1.H18MoreSectionsPDF (2 MB)Download PDF ToolsExport citationAdd to favoritesGet permissionsTrack citations ShareShare onFacebookTwitterLinkedInWeChat Previous Back to Top Next Download PDF FiguresReferencesRelatedInformation Cited ByBlood volume and cardiac index in rats after exchange transfusion with hemoglobin-based oxygen carriersRussell Migita, Armando Gonzales, Maria L. Gonzales, Kim D. Vandegriff, and Robert M. Winslow1 June 1997 | Journal of Applied Physiology, Vol. 82, No. 6Pathogenesis of Hypertension in Blacks: Features of an Equilibrium Model More from this issue > Volume 237Issue 1July 1979Pages H18-H24 Copyright & PermissionsCopyright © 1979 the American Physiological Societyhttps://doi.org/10.1152/ajpheart.1979.237.1.H18PubMed464065History Published online 1 July 1979 Published in print 1 July 1979 Metrics

Racial Differences in Blood Pressure Control

Children from an entire biracial geographical population were examined for blood pressure. A sample of 278 children, stratified by diastolic blood pressure, was reexamined 1 to 2 years later. Dopamine beta-hydroxylase, renin activity, and resting heart rate were observed in black and white children. In the group with high blood pressure, whites had higher heart rates and greater renin activity than blacks. Dopamine beta-hydroxylase concentrations in blacks were lower than in whites over the entire spectrum of blood pressure levels. High blood pressure seems to have a different metabolic background in the two races which may influence the early natural history of essential hypertension. Therefore, the rationale of prevention, and possibly treatment, of early hypertension in blacks and whites may differ.

Effects of volume expansion and contraction in normotensive whites, blacks, and subjects of different ages.

We studied the blood pressure, natriuretic, kaliuretic and humoral responses of 347 normal subjects after volume expansion and volume contraction to examine possible differences among whites, blacks and subjects of different ages. According to outpatient 24-hour urine collections, blacks excreted less sodium and potassium than whites. After similar states of sodium intake were achieved among all subjects, 2 liters normal saline were given i.v. Blacks and subjects greater than or equal to 40 years excreted less sodium than whites or subjects less than 40 years, over a 24-hour period. In addition, blacks excreted less potassium. The delay in sodium excretion occurred during the first 12 hours after the salt load. Blacks had a greater suppression of plasma renin activity than whites 24 hours after saline. Blacks also had higher blood pressures than whites after saline administration; their pressure remained elevated until furosemide was given. Furosemide, 120 mg over 24 hours, evoked greater natriuresis, but less kaliuresis in blacks than in whites. The greater prevalence of hypertension in both blacks and older subjects may be related to relatively blunted natriuretic responses when these groups engage in the high sodium-low potassium intake characteristic of our society.

Symptoms of hypertension in blacks: Judith A. Filenius, Milwaukee County Medical Complex Hypertension Clinic at the Downtown Medical and Health Services, 2430 West Wisconsin Avenue, Milwaukee, Wisconsin, 53233; Mahendr S. Kochar

The objective of this study was to investigate the effect of methyldiphenyl diisocyanate (MDI) concentration (0, 0.2, 1, 2, and 3%) on the wettability and adhesion of blend solutions of poly(lactic acid) (PLA) and chitosan (CS) when coated on PLA film for development of a bio-based multi-layer film suitable for food packaging and other applications. Characterization was carried out by attenuated total reflectance infrared spectrometry (ATR-FTIR), contact angle (θ), mechanical adhesion pull-off testing, and scanning electron microscopy (SEM). The θ of the PLA/CS blend shifted to a lower value (41–35°) with increasing MDI concentration showing that the surface tension was modified between the PLA/CS blend solution and PLA film and better wettability was achieved. The increase in MDI also resulted in an increased breaking strength (228–303 kPa) due to the increased H-bonding resulting from the more urethane groups formed within the PLA/CS blend as shown by ATR-FTIR. The improved adhesion was also shown by the increased number of physical entanglements observed by SEM. It can be concluded that MDI can be used to improve wettability and adhesion between PLA/CS coating and PLA film.

Renovascular hypertension in blacks: Thomas A. Keith, University of Cincinnati College of Medicine, 231 Bethesda Avenue Cincinnati, Ohio 45267; Nola Lowther; Cynthia Powell

Renovascular hypertension in blacks: Thomas A. Keith, University of Cincinnati College of Medicine, 231 Bethesda Avenue Cincinnati, Ohio 45267; Nola Lowther; Cynthia Powell

Appointment-keeping behavior of black hypertensives: A statistical decomposition: Jeffrey Colman Salloway, Rush University, Rush-Presbyterian-St. Luke's Medical Center, Chicago, Illinois; Fred Coe, Michael Reese Hospital

Appointment-keeping behavior of black hypertensives: A statistical decomposition: Jeffrey Colman Salloway, Rush University, Rush-Presbyterian-St. Luke's Medical Center, Chicago, Illinois; Fred Coe, Michael Reese Hospital

The health belief model as a predictor of compliance among black hypertensives: J. C. Salloway, School of Basic Medical Sciences, University of Illinois, Urbana Illinois; W. R. Pletcher; J. J. Collins

The health belief model as a predictor of compliance among black hypertensives: J. C. Salloway, School of Basic Medical Sciences, University of Illinois, Urbana Illinois; W. R. Pletcher; J. J. Collins

Renal vasculature in essential hypertension: racial differences.

In an attempt to explain the greater morbidity from essential hypertension in the black as compared with the white race, we evaluated the intrarenal vasculature of 27 patients with hypertension (19 white and 8 black). All patients had mild-to-moderate hypertension (mean arterial pressure, 110 to 125 mm Hg), normal renal function, and minimal target-organ damage. All patients had selective renal angiograms, which were evaluated for arterial nephrosclerosis. Additionally, renal blood flow was estimated by the clearance of para-aminohippurate. Patient age, blood pressure, and plasma renin activity did not differ between the two races. Black hypertensives had significantly (P less 0.01) more severe nephrosclerosis than the white patients. Renal blood flow was lower (P less than 0.05) in black patients (390 +/- 35 ml/min - m2 body surface area) than white patients (473 +/- 19 ml/min - m2 body surface area). These findings may help to explain racial differences in morbidity and mortality from essential hypertension.

Target organ damage in black hypertensives.

A representative sample of black hypertensives has been appraised to determine candidacy for hypertension treatment. A total of 1759 black residents were successfully screened at home. Forty-one percent of the males and 33% of the females had diastolic blood pressures of 95 mm Hg or greater. They were invited for secondary screening along with those hypertensives controlled on therapy. Clinical and laboratory evidence of cardiovascular disease was common among examined patients who were studied to determine their eligibility for therapy based on criteria of elevated blood pressure (greater than 104 mm Hg) at two visits, or evidence of end organ damage at lowere blood pressure levels. Of patients previously aware of their hypertension but not on therapy, 88% of the males and 67% of the females were considered candidates for therapy. Of patients not previously aware of their elevated blood pressure, 72% of the males and 67% of the females were considered candidates.

Malignant hypertension in blacks: Malignant intrarenal arterial disease as observed by light and electron microscopy

Volhard and Fahr recognized that hypertensive intrarenal vascular disease could be divided into two groups corresponding to the clinical states of benign and malignant hypertension. Since that time, numerous papers on malignant hypertension, primarily dealing with European derived populations, have emphasized fibrinoid necrosis of small arteries and arteiroles as the lesion of malignant hypertension, although some have also recognized a myxoid intimal lesion as characteristic. Today in the United States, however, a significant proportion of malignant hypertension occurs in blacks. In the present study, patients have lacked fibrinoid necrosis of arterioles and only rarely have had some atypical necrosis of small arteries. The prominent, but not pathognomonic, lesion in this series is a myxoid intimal thickening of small arteries consisting of smooth muscle cells, acid mucopolysaccharides, basement membrane-like material, collagen, and other amorphous and unidentified material, probably plasma derived.

Renin as a risk factor in essential hypertension: More evidence

When patients with essential hypertension are classified into three major subgroups according to their plasma renin levels, they appear to exhibit different physiologic and epidemiologic characteristics. The present study extends previous observations which have suggested that low renin patients are relatively protected from development of heart attacks and strokes. Low renin patients despite the fact that they are older, exhibit lower blood urea levels than patients in the other two groups. These data are in keeping with the idea that low renin patients have relatively less renal vascular involvement. Young hypertensive blacks, known to be most prone to severe hypertension with vascular complications, practically always fall into the normal renin subgroup, whereas, in contrast, a vast majority of those blacks above the age of 50, with relatively milder hypertensive disease, exhibit low renin levels. These new findings which further associate vascular sequellae with the normal or high renin state provide more support for the concept that low renin patients have a relatively benign type of hypertensive disease. Nonhomogeneity of the low renin hypertensive population and differences in methodologic and physiologic approaches used to define such patients may provide the basis for conflicting observations from certain laboratories.

Hypertension Is Different in Blacks

Hypertension is different in black people. It develops earlier in life, is frequently more severe, and results in a higher mortality at a younger age, more commonly from strokes than from coronary artery disease. Experience over the past 20 years with an inner city population readily attests to the high incidence of hypertension in blacks. Studies conducted in the Toxemia Clinic at D. C. General Hospital presented evidence that 70% of the patients originally diagnosed as toxemia of pregnancy by the obstetricians actually had hypertensive vascular disease as shown by a history of an elevated arterial pressure prior to pregnancy, and by arteriovenous nicking seen on ophthalmoscopic examination. 1-3 Studies during the past year conducted in the Birth Control Clinic at this hospital have reemphasized the high incidence of hypertension in young black women. 4 Forty-eight percent of a random sample of black patients attending the Birth Control Clinic were

Systemic hypertension in blacks: An overview of current concepts of pathogenesis and management.

Systemic hypertension is a leading risk factor for cardiovascular disease among Blacks. Essential hypertension in this population is dominantly related to salt-sensitivity acting via various interactive mechanisms including volume changes, nitric oxide inactivation, angiotensin II and insulin resistance. Excess morbidity and mortality among Black hypertensives are related to twin problems of ignorance and poverty, late diagnosis, genetically determined racial biological factors and co-existing diabetes mellitus and obesity arising from "western" adopted affluent life-style. This paper reviews these peculiarities and their implications in the management of a Black Hypertensive.