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

The concentrations of plasma cAMP and plasma renin activity were determined in arterial and renal venous plasma in nineteen patients investigated for renin-mediated hypertension. The cAMP measurements were performed in two different situations (1) under basal conditions and (2) after i.v. dihydralazine administration, a potent renin stimulation procedure. Thirteen patients had a lateralization of the renin secretion in the basal state and the administration of dihydralazine caused a further marked renin-secretion. The cAMP concentration was higher in the renal veins draining renin-positive kidneys than in the contralateral renal veins. No significant change was observed between the arterial cAMP concentration and the cAMP concentration in either of the renal veins during dihydralazine-stimulated renin secretion. There was no correlation between the cAMP extraction and the renin secretion of the individual kidneys, but the cAMP extraction correlated with the extraction ratio of PAH. These results show that cAMP values are mainly influenced by the renal function and are not related to the state of renin secretion. Increased cAMP levels in renovascular patients and urameic patients are therefore mainly due to defective elimination of the nucleotide by the kidneys.
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PMID:Cyclic AMP, renal function and dihydralazine-stimulated renin secretion in hypertensive patients. 23 May 70

Glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) were simultaneously measured by obtaining an isotopic steady state during a continuous infusion of 125I orthoiodohippurate (OIHA). A good correlation was found between the clearances of Ioth (y) and of inulin or polyfructosan (x) : y = 1.18 X (x) + 8.43 (r = 0.96; P less than 0.001) and between the clearances of OIHA (y') and of PAH (x') : y' = 0.62 X (x') + 21.2 (r = 0.93; P less than 0.001). When renal functions were impaired the use of Ioth was not convenient since the infusion time necessary to reach a radioactive plateau was longer than 3 hours. On the contrary, excellent results were obtained by using OIHA. In this case, the main advantages were the absence of urine collection and the rapid obtention of an isotopic equilibrium. The repeated determination of renal clearances in hypertensive or diabetic patients appears to be useful in the study of changes induced by antihypertensive drugs or insulin. Clearances were slightly improved by clonidine, claimed to be useful in hypertension associated with chronic renal failure. GFR and ERPF were rapidly increased by insure on the metabolic and hemodynamic changes induced by insulin than on the return to normal of glomerular basement membrane permeability.
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PMID:Study of renal functions by repeated constant infusion of radiotracers before and after initiation of therapy in hypertension or in diabetes mellitus. 24 Oct 42

Thirty two cases of pulmonary arterial hypertension of unknown etiology (PAH-UE) were studied. The diagnosis was established by exclusion after the results of hemodinamics studies. Ninety percent of cases had severe PAH (100 mmHg). The end diastolic right ventricular pressure was elevated in 46% of cases. The total pulmonary vascular resistance was increased in the order of the 1700 dinas. seg. cm-5. The cardiac index was 3.3 1/m2 with a right ventricular work index of 3.96 K gm min. The total lung capacity (TLC) was normal, with a vital capacity (VC) of 78% of the predicted value. The residual volume was increased. The mean value of the maximal midexpiratory flow rate (MMFR) was 78%. The A-a gradient of O2 was 30 mmHg, with a venous mixture expressed as a percentage ratio of the cardiac output (Qva/Qt) of 26%. The mean paO2 mmHg and the anatomical pulmonary artery to vein shunt (Qs/Qt) was 9%, with a DLco normal. The clinical hemodinamic correlation was in good agreement. Our results suggested that PAH-UE "per se" has effect in pulmonary function changing slight lung mechanics, and in a moderate degree lung gas exchange. The hipoxemia results meanly from V/Q imbalance.
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PMID:[Pulmonary arterial hypertension of unknown etiology. Study of the cardiopulmonary function]. 70 36

Alongside reversible secondary pulmonary arterial hypertension accompanying neonatal respiratory distress, there are primary PAH leading to the persistence of the foetal circulation. This is a true functional neonatal heart disease which may occur alone or be seen in association with another form of neonatal distress such as respiratory distress secondary to the inhalation of amniotic fluid. Any neonatal hypoxaemia irreductible by classical methods should suggest the possibility of persistent pulmonary arteriolar vasoconstriction and lead, in the absence of systemic hypotension, to the administration of vasodilators. These data remain in the preliminary stage and further studies, in particular pharmacological, of these drugs are necessary.
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PMID:[The persistence of foetal circulation. Neonatal pulmonary arterial hypertension. Favourable action of tolazoline (author's transl)]. 71 66

In patients with renovascular hypertension, a significant decrease in glomerular filtration rate (GFR) and in renal plasma flow (RPF) in the stenotic kidney was accompanied by a significant homolateral decrease in extraction of PAH(EPAH) and in net tubular reabsorption of sodium (RNa). There was a highly significant correlation between differences in RNa and differences in either GFR or RPF, while no correlation between differences in RNa and in EPAH was noted. It is suggested that the nature of the relationship between GFR and RNa is essentially the same in unilateral renal artery stenosis in man, as in acute constriction of the renal artery or the aorta in the experimental animal.
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PMID:Relationship between glomerular filtration rate and tubular reabsorption of sodium in patients with unilateral renal artery stenosis. The role of the renal prostaglandins. 84 24

We describe our observations concerning differences in two groups of young hypertensive patients according to their renin activities after ACE inhibition. Seventeen of these patients (age 26 +/- 7 years), so far untreated, were investigated prospectively for hormone levels (renin, aldosterone, vasopressin), microalbuminuria, renal haemodynamics (inulin and PAH clearance) and signs of organ damage (echocardiography, fundoscopy). Secondary forms of hypertension were excluded by routine methods, including angiography. We differentiated two groups of young hypertensive patients. Group 1 (n = 9) had a false positive captopril test with elevated renin activities after ACE inhibition with captopril (8.4 +/- 5 ng/ml per hour) compared to group 2 (renin activity: 2.2 +/- 1.3 ng/ml per hour) or an increase of greater than 400% of renin activity after ACE inhibition. Baseline renin activities and sodium excretion did not differ between the groups. Group 1 also showed significantly greater GFR, FF, and microalbuminuria, as well as signs of organ damage, with left ventricular hypertrophy and hypertensive changes in fundoscopy. There were no differences between the groups concerning mean arterial blood pressure and duration of hypertension. In conclusion, we were able to demonstrate that patients with highly stimulated renin activities showed signs of visceral organ damage and renal hyperfiltration compared to the normal renin activity group after ACE inhibition. Investigations of the renin-angiotensin-aldosterone system with ACE inhibitors might constitute a helpful indicator of renal changes and organ damages in young hypertensive patients.
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PMID:Renal haemodynamics and organ damage in young hypertensive patients with different plasma renin activities after ACE inhibition. 131 92

To characterize the long-term effects of calcium antagonists on renal function in hypertension felodipine was used to treat 14 patients with severe uncontrolled hypertension associated with renal functional impairment: six patients had renal parenchymal hypertension, six had essential hypertension and two had renovascular hypertension. Mean blood pressure was 197 +/- 2/115 +/- 3 mm Hg despite treatment with three or more antihypertensive drugs. Mean glomerular filtration rate (GFR) was 39 +/- 6 ml/min (Cr-EDTA clearance) before initiation of felodipine treatment. All patients experienced a blood pressure reduction after starting felodipine treatment, which persisted during long-term therapy in combination with previous medication except former vasodilating drugs. Blood pressure after 12 and 24 months was 152 +/- 7/89 +/- 2 and 157 +/- 5/90 +/- 2 mm Hg, respectively. Patients with moderately impaired GFR and absence of progressive renal disease (N = 8) manifested an increase in GFR after 6 and 12 months on felodipine (59 +/- 10 to 63 +/- 7 and 70 +/- 6 ml/min, respectively, P less than 0.05). Renal plasma flow (PAH clearance) exhibited only a slight increase (315 +/- 68 to 340 +/- 63 and 314 +/- 69 ml/min) with a consequent increase in filtration fraction (18 +/- 1 to 21 +/- 1 and 20 +/- 1%, NS). At follow-up after six to eight years patients with initial GFR greater than or equal to 50 ml/min had a maintained renal function. In five patients a progressive deterioration of renal function had been documented.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Long-term effects of felodipine in patients with reduced renal function. 161 60

Felodipine, a dihydropyridine calcium antagonist, was used to treat eight patients with severe uncontrolled hypertension: five had essential hypertension, two had renovascular disease, and one chronic pyelonephritis. Mean blood pressure (BP) was 221 +/- 14/120 +/- 4 mm Hg despite treatment with three or more antihypertensive drugs. All patients experienced an immediate and pronounced lowering of BP after adding felodipine, which persisted during long-term treatment in combination with previous medication except for vasodilating drugs. In all cases, an increase in glomerular filtration rate (51Cr-EDTA clearance) after 6 and 12 months of felodipine treatment was seen (59 +/- 10 to 63 +/- 7 and 70 +/- 6 ml/min, respectively, p less than 0.05). Renal plasma flow (PAH clearance) exhibited only a slight increase (315 +/- 68 to 340 +/- 63 and 314 +/- 69 ml/min), giving a nonsignificant rise in filtration fraction (18 +/- 1 to 21 +/- 1 and 20 +/- 1%, respectively). It is concluded that felodipine decreases BP dramatically in patients with previously refractory hypertension and that the drug causes an improved renal function in these patients.
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PMID:Long-term effects of felodipine on blood pressure and renal hemodynamics in severe hypertension. 169 10

23 living related kidney transplant donors were prospectively studied to determine the degree of hyperfiltration which occurs after uninephrectomy and to monitor potential consequences of this procedure such as hypertension, microalbuminuria or renal functional impairment. Standard inulin and PAH clearance studies were performed immediately before (n = 23), one week after (n = 22) and one year after nephrectomy (n = 12). Hyperfiltration was defined as the ratio of (post-nephrectomy inulin clearance)/(0.5 x pre-nephrectomy inulin clearance), hyperperfusion was defined in an analogous way for PAH clearance. One week after uninephrectomy, hyperfiltration averaged 134 +/- 6% (SEM) and hyperperfusion was 138 +/- 6%. The degree of hyperfiltration did not correlate with donor age. One year after nephrectomy, hyperfiltration was nearly unchanged (130 +/- 7%) whereas hyperperfusion had significantly decreased to 119 +/- 8% (p less than 0.05). Blood pressure did not increase after nephrectomy and no new cases of hypertension were observed during follow-up. In contrast, there were two new cases of microalbuminuria at one week and one year after nephrectomy. Further follow-up of these kidney donors is warranted.
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PMID:[Glomerular hyperfiltration following unilateral nephrectomy in healthy subjects]. 175 67

This study was performed to assess changes in renal function accompanying cardiovascular responses to mental stress. Glomerular filtration rate (GFR, inulin clearance), renal plasma flow (RPF, PAH clearance), filtration fraction (FF), sodium excretion, and segmental sodium tubular reabsorption (lithium clearance) were measured in 15 normal volunteers during rest and stress. The psychological stress test used is based on a computerized version of the Stroop word color conflict test. Stress induced a significant (P less than .05) and sustained increase in blood pressure and heart rate. During stress, GFR and RPF did not change whereas FF increased significantly (P less than .05) and sodium excretion tended to decrease. The decrease in sodium excretion was due to a significant (P less than .05) increase in proximal reabsorption, which may be mediated by renal hemodynamic changes. The observed significant increase in FF suggests an increase in postglomerular arteriolar resistances, which may account for the increase in proximal sodium reabsorption through an alteration in peritubular Starling forces. In the long run, the stress-associated increase in sodium reabsorption may contribute to the development of hypertension.
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PMID:Stress-induced renal functional alterations in normotensives. 181 53


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