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Biomedical subjects

E Reisin

Publications and source records attributed to E Reisin.

At least 37 records · Page 2Linked to original sources
PubMed1992

The relation of culturally influenced lay models of hypertension to compliance with treatment.

Problems in compliance with treatment and illness management have frequently been traced to differences between patients' explanatory models of illness and the biomedical model. We investigated the relationship of cultural beliefs about hypertension to compliance with treatment. Using semistructured interviews, we elicited the explanatory models of hypertension held by 60 black hypertensive women being treated at Charity Hospital in New Orleans. The patient sample was followed for 2 months to obtain data on compliance with antihypertensive treatment and blood pressure control. As described, 53% of the patient sample recognized two basic folk illness models: "high blood" and "high-pertension." Patients' illness models were significantly related to compliance with treatment at the P = .01 and .001 levels. Compliance was related to blood pressure control at the P = .05 level. These results indicate that culturally influenced health beliefs are an important influence on compliance and, in turn, blood pressure control. Improved understanding of these problems by physicians may improve the management of their patients' illness.

Black or African American↗
PubMed1992

The treatment of obese hypertensive black women: a comparative study of chlorthalidone versus clonidine.

OBJECTIVE: We attempted to determine a valid pharmacological approach for the control of high blood pressure in obese hypertensive patients using two antihypertensive agents with different pharmacological actions. DESIGN: Thirty-two obese hypertensive black women were randomly treated with chlorthalidone or clonidine to achieve adequate blood pressure control. Unresponsive patients received combination therapy with both agents. RESULTS: Twenty-nine patients completed the study. Systolic and diastolic blood pressures were reduced with both agents, more so with chlorthalidone. Of the 15 patients treated with chlorthalidone, 14 had satisfactory reduction in diastolic pressure compared with only four of the 14 treated with clonidine. Of the 11 unresponsive patients treated with combination therapy, 10 achieved satisfactory control of blood pressure. CONCLUSIONS: We conclude that a rational approach to the treatment of hypertension in obese black women includes diuretics, a first choice attempt that tries to address the hemodynamic alterations previously identified in those patients. Combining diuretics with an alpha-adrenergic agonist resulted in complete control of blood pressure in most of the hypertensive patients in our study. The lowest dose of each antihypertensive medication, especially when used in combination, was effective in a high percentage of patients. The use of this antihypertensive approach also helps to clarify which of the underlying pathophysiological mechanisms should be targeted when other currently available antihypertensive medications are used.

Black People↗
PubMed1990

Sodium and obesity in the pathogenesis of hypertension.

In the present work I focus on the pathophysiological mechanisms that may explain the association between high sodium intake, obesity and high blood pressure. Despite epidemiological and etiological controversies on the link between excess sodium in the diet and elevated arterial pressure, the association could be explained on the basis of three different pathophysiological mechanisms: (1) abnormal electrolyte transport across cell membranes, a defect that alters sodium/potassium exchange and also sodium/calcium exchanges, increasing the concentration of intracellular calcium ions that heightens vessel wall tension and the smooth muscle process, (2) increased sympathetic nervous system activity and (3) altered cellular sodium concentration that induces waterlogging in the peripheral arteriolar walls. These mechanisms increase peripheral resistance and enhance arterial pressure. Early epidemiological studies documented a strong association between obesity and hypertension; and a greater incidence of high blood pressure and diabetes was reported in persons with upper body obesity (high waist/hip ratio). Researchers have explained obesity-related hypertension accordingly with various mechanisms. Hyperinsulinemia and vascular resistance may trigger the metabolic and adrenergic changes described in obese hypertensive patients in several ways. Insulin may increase absorption of sodium in the diluting segment of the distal nephron with consequent water retention. Alternatively, insulin might alter sodium/potassium distribution thus causing increased vascular peripheral resistance. The increased sodium stimulates adrenergic activity. The water retention in obese subjects increases absolute volume that is predominantly redistributed in the cardiopulmonary area, leading to augmented venous return and cardiac output. These changes in association with a total peripheral resistance considered inappropriately normal, are the main hemodynamic characteristics of obesity-related hypertension.

Blood Pressure↗
PubMed1990

Intravenous fenoldopam versus sodium nitroprusside in patients with severe hypertension.

In an open-label study, we compared the efficacy and safety of intravenous infusion of fenoldopam mesylate with that of sodium nitroprusside in patients with severe hypertension or in hypertensive crisis. Both antihypertensive medications were infused at a maximal dose increment of 0.2 microgram/kg/min (fenoldopam) and 1 microgram/kg/min (nitroprusside), with a maximal infusion rate of 1.5 micrograms/kg/min fenoldopam mesylate or 8 micrograms/kg/min sodium nitroprusside. Once the desired reduction in diastolic blood pressure was achieved (less than 110 mm Hg if initial diastolic blood pressure was 120-149 mm Hg, or by at least 40 mm Hg if initial diastolic blood pressure was 150-190 mm Hg), the maximal infusion rate used was maintained for at least 1 hour, and then, the infusion was slowed gradually over 2 hours. After the infusion treatment, patients remained in the hospital for 2 days of follow-up. Both antihypertensive agents successfully controlled the blood pressure in all the patients by the end of the maintenance periods. Between the baseline and the end of the maintenance period, analysis of variance showed that the changes in the variables induced by fenoldopam mesylate did not differ significantly from those induced by sodium nitroprusside. The incidence of side effects listed were similar in both groups of patients. The detection of toxic levels of thiocyanate in two patients treated with nitroprusside, however, shows that fenoldopam might be preferable for the control of a hypertensive crisis or severe hypertension in patients with decreased renal function.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗
PubMed1987

Hypertension and obesity in rats with ventromedial-hypothalamic lesions and low salt intake.

The arterial hypertension that frequently coexists with ventromedial hypothalamic (VMH) lesion-induced obesity has been obtained in rats chronically sustained on diets of standard-to-high salt content. Since VMH lesions also compromise the renal circulation and enhance ingestion of salt-loaded diets, the resulting haemodynamic adjustments, including hypertension, have been interpreted as possibly being sodium-dependent. This notion implies that chronically restricting dietary salt would ameliorate the hypertension, whereas the persistence of hypertension under such a regiment would suggest the potential contribution of non-sodium-related factors. This study assessed whether chronic maintenance of a low-salt diet would buffer the hypertensive and haemodynamic consequences of obesity, accompanying electrolytic VMH lesions in male Wistar-Kyoto (WKY) rats, compared with sham-treated controls. Despite the low-salt diet, the results showed that VMH obesity was accompanied by hypertension, elevated plasma norepinephrine, and redistribution of blood flow away from the brain, kidney and splanchnic organs. The compatibility of these results with earlier studies permitting salt ingestion, is difficult to reconcile with the notion that VMH-hypertension is sodium-dependent. Instead, it suggests that the VMH obesity-hypertension syndrome may provide a useful model for clarifying the autonomic consequences of either augmented carbohydrate ingestion of hyper-insulinaemia.

Animals↗
PubMed1987

Renal haemodynamic studies in obesity hypertension.

Previous investigations have reported the systemic haemodynamic characteristics of obese hypertensive patients; however, their renal haemodynamics have not been explored. This report compares the renal and systemic haemodynamic findings in obese and lean normotensive and hypertensive patients. Our results demonstrate that both normotensive and hypertensive obese subjects had an increased renal blood flow, total blood volume and cardiac output, with decreased total peripheral and renal vascular resistances in comparison with lean normotensive and hypertensive patients. Body weight correlated directly and significantly with total blood volume, cardiac output and renal blood flow but indirectly with total peripheral resistance. Therefore, the elevated cardiac output and volume expansion found in obese patients were associated with increased renal perfusion; this increased renal blood flow accounts for the reduced renal vascular resistance in patients with obesity hypertension. Thus, we suggest that this effect of volume expansion in obesity could counteract the opposing effect of active vasoconstriction produced by the hypertensive disease and may account for the difference in prognosis of obese and lean hypertensive patients.

Adult↗
PubMed1987

Macronodular lesions associated with Staphylococcus aureus bacteremia. A condition that resembles a 'lymphocutaneous' syndrome.

A 54-year-old man, diagnosed as having Wegener's granulomatosis and treated with a regimen of cyclophosphamide and prednisone and hemodialysis, was found to have Staphylococcus aureus in blood, urine, and pus that were removed from the infected area. He had unusual macronodular lesions of the skin that resembled the lymphocutaneous syndrome. These lesions resolved with antibiotic therapy. To our knowledge, this condition has not been described previously.

Arteriovenous Shunt, Surgical↗
PubMed1986

Weight reduction in the management of hypertension: epidemiologic and mechanistic evidence.

A number of studies have established a close association between increased body mass and elevated blood pressure. The presence of obesity in hypertensive subjects is associated with some hemodynamic, metabolic, and endocrinic characteristics: an increased intravascular volume with a high intracellular body water/interstitial fluid volume ratio, increased cardiac output, stroke volume, and left ventricular work while peripheral resistance was reduced or normal. Weight loss of at least 10 kg can reduce blood pressure independently of changes in sodium intake in obese persons of both sexes with mild, moderate, or severe high blood pressure. The fall in arterial pressure in obese hypertensives after weight loss may reverse many of the previously mentioned altered findings and underscore previous epidemiological studies that have shown that weight control could be an important measure in the treatment of hypertension.

Blood Pressure↗
PubMed1985

Failure of cyclo (His-Pro) to exhibit natriuretic activity.

Administration of exogenous cyclo (His-Pro) to dogs has been reported to elicit natriuresis. In contrast, our data fail to show any natriuretic activity of cyclo (His-Pro) in dogs or rats. The possible reasons underlying this discrepancy are discussed.

Animals↗
PubMed1985

Body composition and its relation to systemic haemodynamics, fluid volume partitions and energy utilization in rats with bilateral ventromedial hypothalamic lesions.

Body composition and its relationship with intra-arterial pressure, fluid volume partitions and oxygen consumption were studied in male rats four months following ventromedial hypothalamic (VMH) destruction during the static phase of the development of obesity. Compared with sham-operated controls, rats with VMH lesions had a greater body weight which was related to an increased body lipid content and an elevated arterial pressure and total peripheral resistance. Fluid volume distribution was normal and total body oxygen consumption (per unit of body weight) was reduced. Bilateral destruction of the ventromedial hypothalamus was confirmed in each of the rats studied and no relationship could be demonstrated between the lesion size and the magnitude of haemodynamic changes. It is concluded that the increased arterial pressure observed in obese VMH lesioned rats was directly related to an elevated total body lipid content.

Animals↗
PubMed1985

The cardiovascular and metabolic effects of mixtures of acetate and succinate: a potential improvement in dialysate solutions.

Various mixtures of acetate (AC) and succinate (SUCC) were studied for their metabolic and cardiovascular (CV) effects in 10 dogs. The CV effects seen with all mixtures were similar to those reported for SUCC alone with the only changes being increased cardiac output and decreased total peripheral resistance. The 50:50 per cent AC/SUCC offered the advantage of a rapid but less marked and more sustained HCO3 production. The pH changes in all mixtures followed HCO3 values. Since the addition of SUCC seems to reduce the untoward CV changes seen with AC alone, the ratio of AC/SUCC should be based on metabolic considerations. The present data suggest that a 50:50 per cent AC/SUCC mixture is optimal for metabolic and CV effects.

Acetates↗
PubMed1984

Impaired systemic arterial compliance in borderline hypertension.

Arterial compliance was evaluated by pulse wave velocity, pulse pressure/stroke volume, and by an exponential analysis of the diastolic blood pressure decay curve in three groups of normotensive, borderline hypertensive, and established essential hypertensive patients. Two of the above three indices reflected significantly impaired arterial compliance in borderline hypertension, and all three indices were distinctly abnormal in patients with established hypertension. A close correlation among the three indices was observed in the entire study population. Multiple regression analysis indicated that age (p less than 0.005), systolic (p less than 0.005) and diastolic (p less than 0.025) pressure were independent determinants of pulse wave velocity; other factors such as total peripheral resistance, pulse pressure, and stroke volume were not. We conclude that arterial compliance becomes impaired early in hypertensive cardiovascular disease at the time when arterial pressure may be only slightly elevated. Thus structural alteration of the arterial wall can be demonstrated in borderline hypertension. Age, systolic and, to a lesser degree, diastolic pressures are the best determinants of arterial compliance in large vessels and are therefore important risk factors for evolving systemic arterial disease in essential hypertension.

Adult↗
PubMed1983

Immediate hemodynamic effects of a new calcium-channel blocking agent (nitrendipine) in essential hypertension.

The immediate hemodynamic effects of a new calcium-channel blocking agent nitrendipine were studied in 12 patients with mild established essential hypertension. According to the response to mean arterial pressure, patients were classified into responders (decrease greater than 10 mm Hg, 7 patients) and nonresponders (less than or equal to 10 mm Hg, 5 patients). The decrease in arterial pressure in responders was associated with a significant (p less than 0.01) decrease in total peripheral resistance and a significant (p less than 0.05) increase in heart rate, cardiac index, and left ventricular ejection rate. The plasma norepinephrine level was significantly (p less than 0.05) increased in the responders. The response to upright tilt was qualitatively similar to pretreatment values. Thus, nitrendipine lowered arterial pressure as a result of arteriolar dilatation associated with a reflexive increase in heart rate and cardiac index. These hemodynamic properties make the drug particularly apt for use in combination with beta-adrenergic blockade for the treatment of arterial hypertension.

Adult↗
PubMed1983

Disparate cardiovascular effects of obesity and arterial hypertension.

Since obesity and essential hypertension frequently coexist, a study was designed to analyze some of their cardiovascular effects. Twenty-eight obese patients, half of whom were normotensive and half with established hypertension, were matched for mean arterial pressure with 28 corresponding lean subjects. Systemic and renal hemodynamics, intravascular volume, plasma renin activity, and circulating catecholamine levels were measured. Obese patients had increased cardiac output (p less than 0.001), stroke volume (p less than 0.001), central blood volume (p less than 0.02), plasma and total blood volume (p less than 0.01), and decreased total peripheral resistance (p less than 0.001). In contrast, cardiac output, central blood volume, and stroke volume of hypertensive patients were normal, but they had increased total peripheral (p less than 0.001) and renal vascular resistance (p less than 0.001) and a contracted intravascular volume. Left ventricular stroke work was elevated to a similar level in obesity (p less than 0.001) and hypertension (p less than 0.02), but the increase was caused by an expanded stroke volume in the former and by an increase in systolic pressure in the latter. It is concluded that the disparate effects of obesity and hypertension on total peripheral resistance and intravascular volume counteract and may even offset each other. Thus, obesity may mitigate the effects of chronically elevated total peripheral resistance (and therefore end-organ damage) in essential hypertension. Since both entities affect the heart through different mechanisms, their presence in the same patient results in a double burden to the left ventricle, thereby gently enhancing the long-term risk of congestive failure.

Adult↗
PubMed1983

Racial differences in cardiac adaptation to essential hypertension determined by echocardiographic indexes.

Epidemiologic data point to racial differences in cardiac adaptation to hypertension. In this study, echocardiography and measurement of systemic hemodynamics were performed in 30 black and 30 white patients with untreated essential hypertension. Each black patient was matched with a white patient for age, sex and mean arterial pressure. Wall thickness measurements were similar, but left ventricular mass index was significantly increased in blacks (probability [p] less than 0.05). There was a nonsignificant increase in the number of black patients with posterior wall thickness greater than 1.1 cm. Only in black patients was posterior wall thickness related to systolic (r = 0.45; p = 0.008) and diastolic (r = 0.44; p = 0.0042) pressure and to total peripheral resistance (r = 0.32; p less than 0.046). Thus, although ventricular wall thickness changes are similar in black and white patients, qualitative differences exist in the cardiac adaptive process to systemic hypertension.

Adaptation, Physiological↗
PubMed1983

Hemodynamic effects of intravenous labetalol in essential hypertension.

Labetalol inhibits alpha- and beta-adrenergic receptors. Systemic and regional hemodynamic alterations after intravenous labetalol and its cardiovascular reflexive and metabolic effects were evaluated in 12 subjects with mild to moderately severe essential hypertension. Supine systolic, diastolic, and mean pressures were reduced (from 180/101 and 125 to 149/86 and 109 mm Hg; P less than 0.001). The fall was accentuated during head-up tilt and was accompanied by decreased cardiac output and central blood volume in subjects in both the supine and tilted positions. Neither heart rate nor total peripheral resistance was changed by labetalol, suggesting that venodilation resulting from alpha-adrenergic-receptor inhibition played an important role in arterial pressure reduction.

Adult↗