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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To determine whether altered vascular reactivity could contribute to hypertension after repair of coarctation, the change in forearm and calf vascular resistances to small intra-arterial infusions of norepinephrine were measured in six patients who had undergone surgical correction of coarctation of the aorta but still had upper extremity hypertension and compared with similar measurements made in five normotensive patients with mild heart disease. Only the mean upper extremity pressure was significantly greater in the group that underwent repair of coarctation (102 +/- 11 vs 83 +/- 5 mm Hg, p less than .05, for mean arm pressures and 96 +/- 13 vs 83 +/- 7 mm Hg for mean leg pressures in patients who had coarctation vs normotensive patients, respectively). Forearm and calf blood flows were measured in the right arm and leg with a mercury-in-plastic strain-gauge plethysmograph. Forearm and calf vascular resistances were calculated by dividing mean arterial pressure of the appropriate extremity by the blood flow of that extremity. Norepinephrine was infused into the right brachial and femoral arteries of the patients at doses of 0.02, 0.05, 0.1, 0.2, 0.3, 0.5, and 0.7 microgram/min. Resting forearm and calf vascular resistances were similar in both groups of patients. The norepinephrine dose-response curves showed that control patients required more than three times the norepinephrine to produce the same percent increase in forearm vascular resistance (after 0.2 microgram/min forearm vascular resistance increased by 55% in the coarctation group, while the resistance in the control group increased by only 3%, p less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Increased forearm vascular reactivity in patients with hypertension after repair of coarctation. 397 23

Indirect sphygmomanometric blood pressure measurement is the established method of diagnosing and monitoring hypertension, but it may overestimate the true blood pressure in certain elderly patients leading to unnecessary or excessive treatment. The authors studied 36 elderly (aged 60 years or older) hypertensive men and compared direct intraarterial diastolic blood pressure (DBP) measurements with indirect DBP measurements obtained concurrently by a standard mercury sphygmomanometer and also by an automatic blood pressure recorder to: assess the presence and degree of overestimation of DBP by indirect cuff measurement, and evaluate an alternative noninvasive method. The difference between sphygmomanometric and intraarterial DBP was 10 mmHg or greater in 14 of 36 patients, whereas that between the automatic recorder and intraarterial DBP was 10 mmHg or greater in 14 of 36 patients, whereas the between the automatic recorder and intraarterial DBP was 10 mmHg or greater in only three of 36 patients (P less than 0.05). Fourteen patients (39%) had a DBP of greater than or equal to 90 mmHg by the mercury sphygmomanometer compared with five patients (14%) by intraarterial measurement (P less than 0.05); only seven patients (19%) had a DBP of greater than or equal to 90 mmHg by the automatic recorder (P = .7). Thus, in the authors' patient population: indirect sphygmomanometer overestimated the frequency of elevated DBP by nearly threefold compared with intraarterial measurements, and the automatic recorder closely approximated intraarterial values offering a more accurate, noninvasive measure of DBP in the elderly.
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PMID:Overestimation of diastolic blood pressure in the elderly. Magnitude of the problem and a potential solution. 404 82

The efficacy of MK 421 and propranolol was compared in 48 patients with mild to moderate hypertension. Each patient was randomly assigned to receive 1 of the drugs for 12 weeks. Additionally, a subgroup of 28 patients underwent studies of forearm arterial and venous circulation by means of pulsed Doppler and mercury-in-silastic plethysmography. Both drugs reduced supine and standing blood pressure (BP) (p less than 0.001). Propranolol reduced heart rate (p less than 0.001), while MK 421 did not change it. Brachial artery diameter, blood velocity and flow increased after MK 421 (p less than 0.001), but were not changed after propranolol therapy. Forearm vascular resistance decreased after MK 421 (p less than 0.001) and after propranolol (p less than 0.05). Forearm venous tone was unaffected on MK 421, but increased after propranolol (p less than 0.01). Thus, in moderate hypertension, 3 months of treatment with MK 421 or propranolol similarly decrease BP, but affect the forearm circulation differently: MK 421 dilates both the brachial artery and the arterioles of the forearm, but does not affect the venous vessels, and propranolol causes little arterial change but increases the forearm venous tone.
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PMID:Comparison of oral MK 421 and propranolol in mild to moderate essential hypertension and their effects on arterial and venous vessels of the forearm. 632 65

The first two cases outlined above with intractable massive proteinuria and uremia, were followed and treated with standard medical therapy and dialysis. After a period of study and demonstration of clinical deterioration both patients were given solutions containing sodium mercaptomerin. Within days there was a decline in urine protein excretion and a variable increase in serum protein concentration. The patients demonstrated an increase in blood pressure, which made hemodialysis treatment possible. No deleterious effects from the mercury salts were noted. These observations suggest that in selected cases nephrotoxic agents may be of value in decreasing massive proteinuria, and improving protein homeostasis in uremic patients. The ideal agent should be non-toxic to other organs and produce selective renal ablation (15). Although mercury is not the ideal agent, in these cases it did not produce observable side effects. This new method, applicable to dialysis patients with massive proteinuria, and of help in the control of uncontrollable hypertension in uremia, is an interesting new approach for our therapeutic armamentarium.
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PMID:Medical nephrectomy: the use of metallic salts for treatment of end stage massive proteinuria and renal hypertension. 633 53

Double-blind, placebo-controlled studies show that drug treatment of hypertension does not significantly reduce morbidity and mortality at diastolic pressures less than 105 mm of mercury. Nevertheless, most physicians start drug therapy at 90 to 104 mm of mercury. Few reports have dealt with the level to which blood pressure should be reduced. Available data, including reports from two large-scale studies, suggest that excessively low diastolic pressure due to drug therapy may cause an increase in deaths from coronary heart disease. Other studies suggest that reducing diastolic pressure below 100 mm of mercury does not enhance the prevention of complications of hypertension nor the reversal of pretreatment secondary change. Therefore, it is suggested that drug treatment of hypertension should be begun only if diastolic pressure is consistently 105 mm of mercury despite hygienic measures of treatment. A goal diastolic pressure of at least 100 mm of mercury is suggested.
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PMID:Hypertension--indications, goals and potential risks of drug therapy. 650 83

A 31 year-old inhabitant of French Guiana was prescribed mercuric iodide per os for two and a half months. Shortly before the end of the treatment he developed fasciculations in the trunk and particularly the lower limb muscles, distal painful paresthesias with vasomotor disorders, episodes of excessive perspiration and palmoplantar erythema, moderate fluctuating hypertension, progressive loss of weight and irritability with insomnia. Clinical and electrical signs of neuropathy were lacking. The clinical picture was that of Morvan's fibrillary chorea with acrodynia, the conditions of onset strongly suggesting a mercurial intoxication. Blood and particularly urine mercury levels were elevated. Administration of dimercaprol (BAL) considerably increased urinary excretion of mercury and there was progressive improvement and finally recovery after two months of BAL treatment. This case exemplifies the possible co-existence of fibrillary chorea and acrodynia. Whereas in many cases of fibrillary chorea a precise etiology cannot be determined, the affection can be induced by mercury as by gold administration. The fact that cases of fibrillary chorea due to mercury poisoning are rarely reported may be the result of individual patient hypersensitivity or particular metabolic absorption and excretion features of mercury. This case cannot be included within the continuous activity syndrome of muscle fibers described by Isaacs, since muscle contractures were absent and there was associated acrodynia. Moreover, there was no latent polyneuropathy, in spite of the intense fasciculations. It must be concluded, therefore, that in spite of its rarity fibrillary chorea should keep its semiologic autonomy.
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PMID:[Morvan's fibrillary chorea and acrodynic syndrome following mercury treatment]. 652 13

Two groups of male Sprague-Dawley rats received from weaning 50 micrograms/ml of mercury as mercuric chloride (HgCl2) in drinking water for 320 and 350 days. Hg exposure increased cardiac inotropism, without chronotropic changes, in both groups, and induced arterial hypertension in the rats exposed for 350 days. In the exposed rats, cardiovascular responses to the stimulation of peripheral alpha and beta adrenoceptors were decreased and increased, respectively, possibly through a reduced intracellular availability of calcium ions for contractile mechanisms. Hg exposure did not affect either vagal or sympathetic activity or cardiovascular reactivity to several physiological agonists. On the other hand, Hg exposure induced baroreflex hyposensitivity and produced a drastic alteration of the levels of copper and zinc in brain and kidney.
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PMID:Cardiovascular homeostasis in rats chronically exposed to mercuric chloride. 659 6

The need for a National Blood Pressure (BP) Survey in Nigeria prompted this pilot study. It was aimed at a target population of 50,000 Nigerians on National Service representing the 19 States of Nigeria. Five-hundred-and-eighty-five subjects aged 18-54 years (18.3% of study population [465 male (79.5%) and 120 female (20.5%)] from a population of 3,200 Corps members had their BP measured with a mercury sphygmomanometer in August 1982. Of these, 102 subjects (17.4%) and 47 subjects (8.0%) had BO greater than or equal to 140/90 and greater than or equal to 160/95 mmHg respectively. Only 17 subjects (16.7%) came back for a recheck and 14 (13.7%) remained hypertensive. More males had BP greater than or equal to 140/90 (P less than 0.05). There was a rise in BP with age in both sexes but mean systolic and diastolic BP were higher in males in all age groups. With a prevalence of 8.0% of hypertension and the chosen target population, a National BP survey would be a feasible and cost effective programme for Nigeria.
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PMID:Towards Nigeria's first National Blood Pressure Survey: a pilot study of arterial blood pressure in members of the National Youth Service Corps. 659 70

Previous studies have shown abnormalities of the microvasculature in the spontaneously hypertensive rat and human subjects with established hypertension. We have studied the conjunctival microvasculature in relation to systemic and forearm hemodynamics in 24 normal subjects (NL) and 10 subjects with intermittent elevation of blood pressure (BHT). Macrophotographs of the conjunctival circulation were measured for arteriolar diameter and density of arterioles, capillaries, and venules. Blood pressure was measured by Arteriosonde, cardiac index by echocardiography, and forearm hemodynamics by mercury-filled strain-gauge venous occlusion plethysmography. Average diastolic blood pressure in the NL group was 74 +/- 1.7 mm Hg, while that of the BHT subjects was 89 +/- 3.1 mm Hg (p less than 0.005). Capillary density, venous density, and total vascular density were significantly lower in the BHT than NL group, while arteriolar density did not differ significantly. Cardiac index was significantly higher, and peripheral vascular resistance significantly lower, in the BHT as compared to the NL subjects. Forearm blood flow was higher in the NL subjects. The diameter of the preterminal arterioles of the BHT subjects was 27% greater than NL (p less than 0.02). The capillary density was inversely related to the cardiac index (r = -0.482, p less than 0.01), but was not related to blood pressure (r = -0.207). We conclude that the high cardiac output phase of early essential hypertension in humans is accompanied by a reduction in the number of filtering capillaries, and that the rarefaction of capillaries is more closely related to the elevation of cardiac output than to raised blood pressure.
Hypertension
PMID:Attenuation of the microcirculation in young patients with high-output borderline hypertension. 665 50

Essential hypertension in children is difficult to define and is probably very rare. Of 44 children and adolescents diagnosed between 1966 and 1980 to have essential hypertension, we found that only 8 patients continued to be hypertensive, 3 patients turned out to have secondary hypertension and only 5 patients continued to have elevated blood pressures. The incidence of obesity was high in our patients initially diagnosed to have hypertension, but had normalized their weight at the time of reevaluation. The patients with sustained hypertension had initial diastolic blood pressures over 90 mm of mercury at an age of under 12 years and over 100 mm of mercury when older than 12 years of age.
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PMID:[Does essential hypertension exist in childhood?]. 666 52


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