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C Posadas

Publications and source records attributed to C Posadas.

26 records · Page 2Linked to original sources
PubMedDate not supplied

[Effect of inhibition of converting enzyme by captopril on arterial pressure, renin and aldosterone in essential hypertension].

The response of arterial blood pressure, plasma renin activity (PRA) and plasma (PA) or urinary aldosterone (UA) concentrations to the administration of captopril, was studied in patients with established essential hypertension. Captopril was effective in lowering significantly the blood pressure (189.4/111.2 +/- 23.9/9.7 to 163.4/98.1 +/- 20.7/8.6 mmHg. mean +/- SD, p less than 0.01/0.001). Normal arterial blood pressure values (140.4/86.5 +/- 20.7/10.8 mmHg, were achieved by the addition of hydrochlorothiazide. Captopril administration was followed by a decrease in PA and in UA and an increase in PRA, suggesting the inhibition of angiotensin II formation. Captopril attenuated hypokalemia and hyperaldosteronism produced by the simultaneous administration of hydrochlorothiazide.

Aldosterone↗
PubMedDate not supplied

[Pheochromocytoma and catecholamines. Experience in 63 cases studied for 25 years].

The usefulness of fluorimetric techniques in the diagnosis of pheochromocytoma was investigated. In the 63 cases studied during 25 years by measuring simultaneously various aminergic parameters, including plasma catecholamines and urinary adrenaline (A), noradrenaline (N) and vanilmandelic acid (VMA), we were able to establish the diagnosis of pheochromocytoma in all cases. Adrenaline excretion was found to be higher in patients with tumors located on the adrenal region, whereas N excretion was predominantly increased in patients with extra-adrenal tumors. In patients having tumors smaller than 50 g, A + N excretion was higher and VMA was lower than in those whose tumors were heavier; therefore in cases with small tumors the ratio VMA/A + N was lower than in those with larger tumors. It is concluded that simultaneous measurements of PC, A, N and VMA allow the diagnosis to be made in the most patients with this tumor. On the other hand, the predominant increase in A excretion is suggestive of adrenal pheochromocytoma.

Adolescent↗
PubMedDate not supplied

[Aldosteronism after hypokalemia in diuretic therapy of systemic arterial hypertension].

Twenty-two cases with essential arterial hypertension were studied in the final part of a chronic period of treatment with Chlortalidona and in the first 30 days after treatment. Measurements of the following parameters were made: 1) Change in the excretion of urinary aldosterone (aldo). 2) Change in the arterial pressure (delta P). 3) Transtherapeutic serum potassium (delta K). 4) Change in the Q-T (delta QT) in the electrocardiogram. The measurements were made 3 days after the suppression of the drug and afterwards every 3 to 6 days for a month. The correlation of the K and QT was significant (r = 0.63). The P did not correlate with the K nor with the aldo (r = 0.14). The aldo was -5.92 +/- 3.1 ug./24 hs (p = 0.01) in those cases responsive to the drug. The disappearance of the antihypertensive effect occurred at 9.61 +/- 3.7 days and correlated with the normalization of the QT (r = 0.83) and the serum potassium. The delta aldo correlated with K (r = 0.56) and normalized 6.7 days after the suspension of the drug. The secondary aldosteronism participates in the parogenia of the transtherapeutic hypokalemia although with a slightly significant correlation. The important correlation between the disappearances of the antihypertensive effects and the electrocardiographic signs of hypokalemia may dwell in changes which directly or indirectly exercise the diuretic in the intracellular metabolism of K without necessarily cousing an antihypertensive effect additive of the same hypokalemia.

Adult↗
PubMedDate not supplied

[Effect of sub-pressor doses of dopamine on renin secretion in the anesthetized dog].

The effects of dopamine, its precursor L-dopa, and the dopaminergic agonist bromocriptine (BEC), on plasma renin activity (PRA), in pentobarbital anesthetized male dogs were investigated. Infusion of dopamine at a dose which did not change blood pressure ( 4 ug/kg/min) had no effect on the secretion of renin, nor did it produce modifications in the PRA response to furosemide (10 mg i.v.). L-dopa, in single dose of 500 mg (p.o), significantly augmented PRA two hours after administration, and the renin values remained elevated throughout the observation period of 120 minutes. However, BEC (2.5 mg p.o.) produced no changes in PRA during this time period. We conclude that at the dose utilized, dopamine apparently has no influence on the secretion of renin, and does not modify the increase in PRA provoked by diuretic. It is possible that the L-dopa induced augmentation in PRA is due to stimulation of the juxtaglomerular cells, by the noradrenaline formed in peripheral tissues from administered L-dopa.

Animals↗
PubMedDate not supplied

[Primary aldosteronism. Diagnostic aspects and treatment].

Despite the relatively low frequency of primary aldosteronism, its diagnosis is of great importance because surgical treatment results, in the majority of cases, in the disappearance of arterial hypertension. We present in this paper six cases with this type of secondary hypertension. The disease was suspected by the coexistence of hypertension and hypokalemia. The decrease in serum potassium after an oral load of salt proved to be of great value for the diagnoses. In the five patients treated surgically, the removal of the tumor produced the normalization of the arterial pressure and corrected the biochemical alterations. In four of the patients the tumor was located in the left adrenal gland and in one in the right adrenal gland. The patient not treated surgically has remained normotensive with spironolactone. This data confirm what has been described in the medical literature and emphasizes the importance of a correct diagnosis and treatment in patients with this form of hypertension.

Adenoma↗
PubMedDate not supplied

[The renin-angiotensin-aldosterone system in the diagnosis of renovascular arterial hypertension].

Twenty one subjects with sistemic arterial hypertension and arteriographic signs of obstructive lesion of the renal artery were studied and classified in 3 groups: group A, 13 cases with bilateral renovascular lesions; group B, 4 patients with unilateral renovascular stenosis and group C, formed by 4 subjects with a segmental branch stenosis of a renal artery. In all cases an special protocol was followed to measure plasma renin activity (PRA) in blood taken from a peripheral vein, inferior vena cava and both renal veins and also to determine 24 hrs. urinary excretion of aldosterone (UEA). PRA and UEA were clasified as high, normal and low by comparing the results with those of normal subjects in a nomogram estimated in the same laboratory in which PRA and UEA values were correlated with 24 hrs. urinari sodium excretion. Besides, R greater than /R less than index (highest PRA of renal vein blood/PRA of contralateral renal vein) and V-A A index (V = PRA of renal vein blood; A = PRA of inferior vena cava) were calculated. Forty eight and thirty eight percentage of the cases had either high renin in peripheral venous blood or high UEA. Similar data in patients with essential hypertension previously studied in the same laboratory were 12 and 10% respectively. V-A A index was incongruent with the arteriographic image in 3 cases of group B; 4 cases of group A and 2 of group B had a pattern of bilateral stenosis, and one case in each group A and C had a unilateral stenosis pattern. In the other patients the samples were "non representative" due to a high level of PRA in the inferior vena cava blood comparable to PRA of the renal veins. Six cases of group A had a R greater than /R less than index superior to 1.5, which suggested a predominant vascular lesion in one side not always congruent with the arteriographic findings. In 3 cases of group B this index was higher than 1.5 in favor of the ipsilateral lesion. Three cases of group C had a normal R greater than /R less than index and one with a total oclussion of a segmental artery presented an index superior to 1.5, ipsilateral to the lesion. The latter index was of value in the diagnosis of renovascular arterial hypertension.

Aldosterone↗