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

1. Active and acid-activable inactive renin were measured in renal venous and arterial plasma of 18 patients with essential hypertension (EHT) and 19 patients with renovascular hypertension (RVHT). In seven patients with EHT and in 11 patients with RVHT measurements were made before and 25-35 min after an intravenous injection of 300 mg of diazoxide. 2. Under basal conditions the renal vein to artery ratios for active and inactive renin in EHT ranged from 0.71 to 1.96 and from 0.68 to 1.44 respectively. In 14 patients with RVHT the renal vein to artery ratio for active renin on the affected side was above the range found in EHT and in six of them the renal vein to artery ratio for inactive renin was also elevated. 3. The diazoxide-induced release of active renin from kidneys, which had a stenotic artery but were not seriously contracted, was associated with a fall of the renal vein to artery ratio for inactive renin to a value below 1.00. 4. The results indicate that changes in the release of active and inactive renin do not always run in parallel. The findings are compatible with the hypothesis that circulating inactive renin can be activated in the kidney.
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PMID:Renal release of active and inactive renin in essential and renovascular hypertension. 3 2

Angiotensin circulates in the blood as a hormone. Its main target organs are vascular smooth muscle, adrenal gland and the kidney. Hormonal angiotensin increases blood pressure by its vasoconstrictor action, by stimulation of aldosterone secretion and subsequent sodium and water retention, and by the stimulation of catecholamine release. Circulating plasma angiotensin also effects brain mechanisms of blood pressure regulation. In addition to this hormonal function, angiotensin is present in the brain as part of an endogenous brain renin-angiotensin system. Brain angiotensin is not secreted into the blood and can be considered a neurohormone with local function. A role of brain angiotensin in the maintenance of high blood pressure of spontaneously hypertensive rats has been demonstrated. Circulating plasma angiotensin appears to influence brain renin levels and vice versa. Stimulation of specific areas in the brain known to be involved in the regulation of the cardiovascular system, stimulate renin secretion from the kidney. The renin-angiotensin system can therefore serve as an example for the intimate interrelationship between humoral and neurohumoral mechanisms of blood pressure regulation.
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PMID:Humoral and neurohormonal aspects of blood pressure regulation: focus on angiotensin. 3 33

Nadolol, a new beta-adrenergic blocking agent, was administered orally in gradually increasing single daily doses to 13 hospitalized patients with essential hypertension. Maximal doses ranged from 200 to 480 mg/day. Blood pressure was reduced in nine patients and heart rate was decreased in 11 patients. The decrease in blood pressure was either partial or temporary in five of the nine patients who responded. Concomitant administration of the diuretic chlorthalidone decreased blood pressure in a previously unresponsive patient. Nadolol effectively inhibited isoproterenol-induced tachycardia and decreased cardiac output by 18 per cent. Plasma renin activity and plasma aldosterone concentration were not changed significantly by the treatment. Body weight was not altered significantly. Blood pressure response was independent of the pretreatment renin levels or the change in renin induced by nadolol; it was also independent of the changes in cardiac output and heart rate but was more pronounced in patients with milder baseline hypertension. The decline in serum concentration of nadolol was consistent with the drug's reported half-life of 12.2 hours. The results indicate that single daily doses of nadolol alone can reduce blood pressure significantly with minimal cardiodepressant effects and no important side effects. The effectiveness of nadolol may be enhanced by the addition of a diuretic.
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PMID:Effect of nadolol in treatment of hypertension. 3 98

4 patients with hypertensive crisis (glomerulonephritis [n = 2], phaeochromocytoma [n = 1], reno-vascular hypertension [n = 1] combined with encephalopathy, showed a normalisation of blood-pressure up to 18 days during angiotensin-II-blockade with saralasin. Prior, blood pressure was treated insufficiently by intravenous diazoxide and Na-nitroprusside. Increased plasma-renin-activity and plasma levels of catecholamines pointed to an activation of the renin-angiotensin- and sympathico-adrenergic system. A trial of therapy with saralasin--especially, if blood-pressure response to diazoxide and sodium-nitroprusside is insufficient--could be indicated. Side-effects like pressor-reactions are excluded by very low priming doses (0,1 microgram/kg/min); rebound-hypertension at the end of the therapy is avoided by an overlapping therapy with renin suppressing drugs (beta-receptor blockers, clonidine, guanfacinum).
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PMID:[Saralasin in resistant hypertensive crisis (author's transl)]. 3 82

A retrospective study made of 114 cases of renovascular hypertension was undertaken to compare the effectiveness of different types of treatment. In this series, with a follow-up of 18 months to 9 years, a favourable result with regard to blood pressure was obtained in 45% of cases with surgery, in 63% of cases with medical treatment and in 88% of cases if treatment included beta-blockers. Medical treatment represents a valid alternative to surgery in hypertension of this type, regardless of the amount of renin secretion and whatever the criteria of ischaemia. The choice of surgery as a method of treatment thus depends above all upon the age of patient, the type of stenosis and the anatomical risk represented by the vascular malformation. Despite the very spectacular results of medical treatment, it remains essential to seek a renal cause for hypertension, since many renal conditions which require specific treatment present with hypertension alone.
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PMID:[Reno-vascular hypertension: prognosis variations according to the method; surgery, or medical treatment. Retrospective study of 114 cases (author's transl)]. 3 86

1 Cardioselective and non-selective beta-blockers affect to a different degree several aspects of the circulatory homeostasis. The evidence available in this regard has been evaluated and the possible clinical importance of these differences has been discussed. 2 Venous return in partly regulated by beta-receptors (possibly of the beta 2 type) in the venous resistance vessels. Differences in blockade of venous return by the two classes of beta-blockers may, therefore, influence the degree of increase in left ventricular size, left ventricular end diastolic BPs and stroke volume during beta-blockade. 3 At the first part of the dose-reponse curve, non-selective beta-blockers seem to block more effectively renin release than cardioselective beta-blockers. 4 The direction and the extent to which beta-blockers 'directly' affect total peripheral resistance (TPR), is determined by the resultant of the degree of decrease in TPR by blockade of renin release and the extent of the increase in TPR by blockade of the beta 2-receptors in the arteriolar wall. 5 The clinical relevance of these differences could be that--especially in the low doses range--non-selective beta-blockers may be more 'safe' in patients with compromised cardiac function and may be more appropriate for the therapy of high renin hypertension than cardioselective blockers, whereas the latter may be more appropriate for the majority of hypertensive patients who have low to normal renin hypertension.
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PMID:Possible significance of the pharmacological differentiation of beta-blockers for therapy of hypertension. 3 72

1 Patients with borderline (group I) and sustained hypertension (group II) were treated with beta-blocking drugs, diuretics and the combination of both. In the two groups of patients the antihypertensive effectiveness of both short-term intravenous or chronically oral propranolol was directly related to the extent to which the drug produced an absolute reduction in plasma renin activity (PRA). No such a correlation could be obtained with pindolol. In group I following beta-blockade, day-night profiles of PRA were similar to those observed in group II before treatment. Thus, in this latter subgroup, low renin profiles might reflect reduced beta-adrenergic activity. 2 When the chronically beta-blockaded patients were changed to chronic diuretic therapy it became evident that young hypertensive patients of group II showed a more pronounced BP response than the patients of group I. In those patients of group II in whom pressure was not controlled by the diuretic alone, combination with a beta-blocker led to pressure normalization. 3 The beta-blocking drug induced reduction in pressure was greater in the 25-35 yr olds, than in those older than 55. In contrast, the antihypertensive effect of the diuretic was more pronounced in the 55-70 yr olds than in those younger than 40. 4 It is concluded that sympathetic nervous system activity mainly determined PRA as well as antihypertensive effectiveness of both the beta-blockers and the diuretics. As to outpatient management it is proposed that with exception of young borderline hypertensives who seem to respond best to beta-blockers, initial antihypertensive drug therapy may consist of a diuretic agent. If the antihypertensive effect of the diuretic is insufficient, combination with a beta-blocking drug could be used to achieve the best effect.
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PMID:Diuretics, beta-blockers or both as treatment for essential hypertension. 3 74

One hundred and eight patients suffering from hypertension due to a unilateral parenchymatous neophropathy were studied over a period of one to eight years after treatment was starded. The aetiologies were diverse: harmonious hypoplasia, segmental hypoplasia, pyelonephritis, reflux nephropathy, hydronephrosis and tuberculosis. Thirty nine patients were treated surgically, with 50% good results. In 82 cases medical treatment was continued for at least a year with a 52% success rate. Such success was recorded in 94% of cases in which beta-blockers were used (38 cases). Surgical success was not dependent upon the period for which hypertension had been present. The best results were seen in cases of hydronephrosis and pyelonephritis and the worst in tuberculosis. Thirteen patients underwent surgery event though there was no unilateral increase in plasma renin levels. Seven were improved or cured. Ten patients underwent surgery with a renin activity 50% greater than on the healthy side, 9 being improved or cured. Treatment with beta-blockers, alone or in association with diuretics, controlled blood pressure in 90% of cases, regardless of the renin activity. Plasma renin activity in the renal veins is of good prognostic value in terms of the effectiveness of nephrectomy against hypertension. In Call cases, beta-blockers were more effective than surgery.
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PMID:[Hypertension due to unilateral parenchymatous nephropathy (author's transl)]. 3 35

Beta blockade was instituted in 10 patients with renovascular hypertension due to renal artery stenosis or thrombosis. The treatment was very effective in unilateral stenosis with a normal contralateral kidney (2 kidney Goldblatt) and in fibromuscular dystrophy of the renal artery. On the other hand many failures were observed in hypertension with a single kidney (1 kidney Goldblatt) and in renovascular hypertension with complex lesions or associated renal failure. Although a clear relationship was often observed between the increased plasma renin activity and the antihypertensive effect of beta blockade, this association was sometimes completely erroneous. Beta blockade, which is easy to perform, should be tried out systematically in renovascular hypertension, but, when no result is observed, this therapeutic test should not exclude surgical management thereafter.
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PMID:[Renovascular hypertension and beta blockers. Theoretical and practical implications]. 4 14

Ten patients affected by essential moderate or severe hypertension were given five sequential treatments, each for three weeks: 1) placebo, 2) chlorthalidone (Cl) 100 mg daily, 3) Cl 50 mg + oxprenolol slow release (Ox) 160 mg daily, 4) Ox 160 mg and 5) Ox 320 mg daily. Four subjects poor responders (DPB greater than or equal to 110 mmHg) received a later administration of Ox 160 + Cl 50 + hydrallazine (Hydr) 25-100 mg daily. Both groups of patients showed the greatest antihypertensive action with Ox 160 + Cl 50 mg daily. Oxprenolol induced a similar hypotensive effectiveness at 160, as well as 320 mg/day. Relationship between plasma renin activity (PRA) values and antihypertensive response to each treatment takes the following conclusions: 1) Basal PRA levels cannot be a guide for preferential choice of diuretic or betablocking therapy. 2) It is likely that renin activated by Cl and Hydr partially blunts their hypotensive activity. On the contrary, essential hypertension with normal or low PRA does not seem depending on angiogensinogenic factors. 3) Oxprenolol remarkably inhibits the overreninism induced by chlorthalidone and hydrallazine, in such way increasing their antihypertensive action. 4) In the management of essential moderate or severe hypertension is preferable to employ a mild dosage of betablockers and diuretics, rather than use higher doses of a single agent.
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PMID:[The role of renin after betablocking diuretic and vasodilator treatment in essential hypertension (author's transl)]. 4 15


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