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Biomedical subjects

J M Alcázar

Publications and source records attributed to J M Alcázar.

At least 19 recordsLinked to original sources
PubMed2001

Clinical characteristics of ischaemic renal disease.

BACKGROUND: Longer life expectancy has favoured the ever more frequent development of ischaemic nephropathy characterized by the presence of atherosclerotic stenosis in both renal arteries. METHODS: This is an observational and multicentre study carried out during a 14-month follow-up period in 20 hospitals in SPAIN: Inclusion criteria were the presence of bilateral renal artery stenosis > 50% and a creatinine level of > or = 1.5 mg/dl. The diagnosis should be made by arterial digital angiography in every case. RESULTS: A total of 156 patients were included. Their mean age was 68.7+/-9 years, and 78.5% were male. The mean creatinine value of the group was 2.9+/-1.7 mg/dl. Arterial hypertension (BP) with a duration of 12+/-9 years was present in 97.4% of the cases, smoking habits in 69.8%, hypercholesterolaemia (> or = 240 mg/dl) in 62.9% and diabetes in 32.1%. Only 8% of the patients had a body mass index > or = 30 kg/m(2). Associated cardiovascular disease was very frequent: peripheral arteriopathy in 67.5% of the cases, ischaemic cardiopathy in 44.8%, cardiac insufficiency in 32.6% and stroke in 27.3%. In 94.4% of the patients, the lesion affected both renal arteries, with complete obstruction in 23% of the cases. CONCLUSIONS: Diagnostic suspicion of ischaemic nephropathy can be established in non-obese elderly males with chronic renal insufficiency, long-term BP evolution and cardiovascular disease at other levels, above all, peripheral arteriopathy.

Aged↗
PubMed2001

Impairment of renal vasodilation with l-arginine is related to more severe disease in untreated hypertensive patients.

Data remain insufficient to place the decreased response to L-arginine in hypertensive patients within a consistent pathophysiological sequence. The aim of the present study in patients with essential hypertension was to assess the relationships between the response to L-arginine and a set of relevant clinical and laboratory parameters. In this prospective, interventional study, we administered L-arginine to untreated hypertensive individuals and healthy control subjects and measured the clearance of inulin and of para-aminohippurate and a set of biochemical and clinical variables. L-Arginine infusion revealed major differences between control subjects and 1 subgroup (group B) of hypertensive individuals. Group B hypertensives (n=18) had no increase in inulin clearance and no decrease in renal vascular resistance with L-arginine; however, in another subset of hypertensive patients (group A, n=27), the insulin clearance increased and renal vascular resistance decreased similar to the control group (group C, n=11). The ambulatory blood pressure monitoring in group B showed both an increased mean diastolic pressure and a "nondipper" pattern in the nocturnal regulation of arterial pressure. These findings in group B were accompanied by significant alterations in optic fundus and left ventricle hypertrophy and increased microalbuminuria (all, P<0.05). Furthermore, group B individuals had significantly lower values of HDL cholesterol and a higher baseline atherogenic index, plasma insulin level, and glucose/insulin index. We disclose a previously undescribed relationship between end organ repercussion and decreased renal hemodynamic response to L-arginine. Our results may help to understand the mechanisms that lead to target organ damage in hypertension.

Adult↗
PubMed1997

Ischaemic renal injury.

Ischaemic renal injury is becoming one of the main causes of end-stage renal failure. The appearance of new diagnostic methods, as well as the evidence that surgery or percutaneous transluminal angioplasty techniques are capable of inducing a significant degree of recovery in a subset of patients, are encouraging events. The identification of the precise cellular pathogenetic mechanisms of ischaemic injury is an area for future research.

Arteriosclerosis↗
PubMed1994

Randomly allocated study of the effects of standard therapy versus ACE inhibition on micro-albuminuria in essential hypertension.

OBJECTIVE: To compare the effects of standard therapy (diuretic, beta-blocker or both) with those of angiotensin converting enzyme (ACE) inhibition with quinapril on renal function and urinary albumin excretion in patients with essential hypertension. METHODS: A 1-year, placebo-controlled, randomly allocated study was conducted in a group of 40 patients with essential hypertension. Before beginning the active treatment phase, all patients were given a matched placebo for quinapril for at least 14 days. At baseline and after 1, 3, 6 and 12 months of treatment, blood pressure, heart rate, body weight, renal plasma flow, glomerular filtration rate, plasma renin activity, plasma aldosterone and urinary albumin excretion were measured. RESULTS: Both the standard therapy and quinapril produced similar decreases in blood pressure, but only quinapril produced a significant decrease in micro-albuminuria, from 68.5 +/- 16.7 to 47.2 +/- 14.9 mg/24 h (P < 0.05). The renal plasma flow remained constant in both study groups while the glomerular filtration rate and filtration fraction decreased significantly (P < 0.05) in the quinapril group. CONCLUSIONS: The results of this study indicate that long-term therapy for essential hypertension with ACE inhibition has a more favorable effect on micro-albuminuria than standard therapy for an equal level of blood pressure control.

Adrenergic beta-Antagonists↗
PubMed1993

Calcium antagonists and renal protection.

AIM: To review the renal benefits of calcium antagonists. METHODS: Review of published studies. RESULTS: Both experimental and clinical studies have indicated that, apart from being highly potent antihypertensive agents, calcium antagonists may also provide tissue protection and preservation. In three well defined clinical situations, the use of calcium antagonists has proved to be of value. First, in acute renal failure we and others have shown that the administration of dihydropyridine or diltiazem can, by preventing an intracellular calcium overload, avoid the renal damage induced by the use of a radiographic contrast agent. Second, in chronic renal failure, the administration of a calcium antagonist has been shown to be safe and at least similar in efficacy to other commonly used antihypertensive drug classes. Third, in renal transplant patients, calcium antagonists have been shown to prevent both acute and chronic cyclosporin nephrotoxicity. Calcium antagonists have a clear advantage in the case of acute toxicity because they allow faster renal function recovery and a shorter hospitalization time. The mechanisms by which this class reduces cyclosporin toxicity may be related to a reduction in the calcium influx into cells during ischaemic and reperfusion periods, which would reduce the generation of oxygen-free radicals and perhaps reduce thromboxane production. CONCLUSIONS: Calcium antagonists have potential renal protective effects that favour their use in many clinical situations where renal function is impaired.

Animals↗
PubMed1992

Sodium intake does not influence the effect of verapamil in hypertensive patients with mild renal insufficiency.

Information is limited regarding the efficacy of antihypertensive drugs in patients with hypertension associated with renal insufficiency. To address this question, a group of 14 outpatients with essential hypertension and mild renal insufficiency received slow release verapamil 240 mg/day for 14 days after a 4-week washout period. Patients were randomly assigned to a low (4 g/day) or high (11 g/day) salt diet, and crossed over to the alternative diet after 7 days. 24-Hour blood pressure monitoring was performed at the end of the washout period and after 7 and 14 days during verapamil treatment. Verapamil induced a significant fall in mean 24-hour blood pressure that was similar for patients on both diets (p < 0.01). As expected, natriuresis increased significantly during high sodium intake (p < 0.01), and bodyweight fell significantly when sodium intake was reduced (p < 0.05). Meanwhile, serum creatinine and creatinine clearance remained stable. These results indicate that the antihypertensive effect of verapamil is independent of sodium intake even in the presence of mild renal insufficiency.

Blood Pressure↗
PubMed1992

Renal consequences of arterial hypertension.

AIM: To seek ways of improving the prognosis for renal function in the presence of arterial hypertension. BACKGROUND: Nephrosclerosis is a term used to define the renal damage induced by arterial hypertension. The renal vasculature can participate in the genesis of essential hypertension and can suffer the consequences of elevated blood pressure. There is no doubt that antihypertensive therapy has dramatically improved the prognosis for renal function in the presence of arterial hypertension. RESULTS OF LITERATURE REVIEW: There appears to be a need for a further improvement in the prognosis for renal hypertension. At present, the prevalence of nephrosclerosis as a cause of terminal renal failure may be increasing and a progressive fall in renal function in treated hypertensive patients compared to normotensives has been described. CONCLUSIONS: It is not yet clear whether improvements in renal hypertension depend merely on the effectiveness of antihypertensive therapy in reducing arterial blood pressure or whether it will be necessary to improve the metabolic disturbances that accompany hypertension or the renal hemodynamic effects of different drugs before the prognosis for nephrosclerosis can be improved.

Antihypertensive Agents↗
PubMed1989

[Treatment of arterial hypertension in the aged].

The response to different therapeutic schedules in arterial hypertension in the elderly is studied and compared with response to treatment in younger patients. Blood pressure in the elderly was best controlled with non pharmacologic measures and low doses of diuretics; there were no differences between both groups with respect to complications and side effects. The response to angiotensin-converting enzyme inhibitors is also evaluated, presenting good results on blood pressure control without side effects in the elderly, although efficaciousness was higher in younger patients. The possible therapeutic schedules in arterial hypertension in the aged are discussed.

Age Factors↗
PubMed1989

Characterization of the renal effects of an intravenous calcium gluconate infusion in normotensive volunteers.

The effects on renal function of an intravenous infusion of calcium gluconate at subpressor doses have been investigated in a group of seven normotensive male volunteers. In the absence of changes in blood pressure, the calcium gluconate induced a significant increase in renal plasma flow and the glomerular filtration rate (P less than 0.01) with a significant fall in the filtration fraction (P less than 0.01). Both diuresis and natriuresis increased significantly (P less than 0.01), plasma renin activity fell (P less than 0.01) and the urinary excretion of 6-keto prostaglandin F1 alpha (PGF1 alpha) and prostaglandin E2 (PGE2) increased (P less than 0.01). These results indicate that calcium infusion at subpressor doses has renal vasodilating, diuretic and natriuretic properties that appear to be facilitated by an increase in the renal production of vasodilatory and natriuretic prostaglandins.

Adult↗
PubMed1989

Diuretic and natriuretic properties of fenoldopam in chronic renal failure.

The effect of intravenously administered fenoldopam on diuresis and natriuresis was investigated in a group of 10 patients with advanced chronic renal failure. After an initial basal period of 1 h, a fenoldopam infusion was started and maintained for 12 h at rates varying between 0.025 and 0.1 microgram/kg per min. During the study, blood pressure was measured every 10 min and urine volume, natriuresis and creatinine clearance were measured hourly. Fenoldopam induced a significant increase in urine volume, natriuresis and creatinine clearance (P less than 0.05-0.001) accompanied by a small but significant drop in blood pressure (P less than 0.05-0.01). These results show that for advanced chronic renal failure, fenoldopam has diuretic and natriuretic properties that could be of clinical relevance.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗
PubMed1989

[Clinical characteristics of arterial hypertension in the elderly].

The clinical characteristics of systolic and diastolic hypertension in 75 and of systolic hypertension in 50 elderly patients have been studied and the results have been compared to those obtained in 23 normotense elderly controls and 500 young patients with essential hypertension. A greater incidence in cardiovascular and neurologic morbility was observed in the hypertense elderly, existing also a greater incidence of electrocardiographic abnormalities and impairment in renal function. The changes in blood pressure with postural changes and isometric and physical exercise were evaluated in a subgroup of these patients, finding that the elderly with hypertension, specially those with systolic hypertension, showed orthostatic hypotension, and an increase in blood pressure with exercise, reaching levels that could potentially cause the clinical complications.

Aged↗