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The C825T polymorphism of the beta-3 subunit of the protein G (GNB3) has been related to an increased activity of the Na+/H+ exchanger (NHE-1) through the synthesis of an anomalous hyperactive protein. Because of the important role of this system in essential hypertension (EH), we analysed the distribution of the different genotypes of this polymorphism in normotensive subjects (NS) and essential hypertensive patients (EHP), their relationship with the condition of salt sensitivity, plasma sodium and potassium concentrations and plasma renin activity (PRA) in EHP. 144 subjects (78 EHP and 76 NS) were studied. Salt sensitivity was assessed by the rapid protocol of Weinberger and genotype determination for GNB3 C825T polymorphism was performed by PCR. The distribution of the different genotypes was similar among EHP (CC 37.2%; CT 41.1%; TT 16.7%) and NS (CC 32.9%; CT 55.3%; TT 11.8%). In regard to general characteristics of EHP (including blood pressure levels) and the condition of salt sensitivity, there were no differences among the different genotypes. Plasma sodium concentration was higher and plasma potassium was lower in TT patients (141.0+/-1.7 and 3.7+/-0.1) than in CC patients (139.1+/-1.9 and 4.0+/-0.3) p<0.05. CT patients had intermediate values (139.9+/-1.9 and 3.9+/-0.2). PRA values were similar in the three genotypes as were the rest of analytical parameters studied. Our data demonstrate an association between the C825T polymorphism of the GNB3 and plasma sodium and potassium concentrations in EHP, as expression of an increase in NHE-1 activity, without modifications in PRA nor relationship with salt sensitivity.

Background and Objective: The HELLP syndrome is a rare form of preeclampsia with a variable presentation with substantial maternal and perinatal morbidity and mortality. The aim of this study was to determine its clinical and biological characteristics in our hospital., Patients and Method: An observational study of all cases of confirmed HELLP syndrome from 1999 to 2002 was carried out., Results: There were 54 cases of HELLP syndrome. Mean maternal age was 30.06 (16-41) years. 57.4% were primiparous. Mean gestational age at diagnosis of HELLP syndrome was 31.75 (20-41) weeks. Symptoms and signs were dominated by the digestive ones. Hypertension was observed in all cases. 77.8% pregnancies were delivered by caesarean section. Mean birth weight was 1674.52 g (150-3800 g). There were 12 perinatal deaths and one maternal death., Conclusions: HELLP syndrome is an uncommon but potentially serious complication of pregnancy which is associated with an increased risk of adverse maternal and fetal outcomes. Management should be multidisciplinary and based on strict control by maternal and fetal symptoms.

Background: Glucose effectiveness (SG) is a parameter that indicates the glucose ability to clearing itself from the plasma independently of insulin's action. Our purpose was to analyze the cluster characteristics associated with the metabolic syndrome in a group of non-obese, recent-onset hypertensives and to test if there was a correlation with SG and the effectiveness of glucose at basal insulin point (GEZI)., Patients and Method: We studied 36 patients with mild hypertension with normal basal glucose levels. We determined plasma lipid subfractions, apolipoproteins and urate levels. An intravenous glucose tolerance test (TTGI) and minimal model analysis according to Bergman was performed and SG, GEZI and insulin sensitivity (SI) were calculated., Results: Patients with lower SG and GEZI had higher levels of total triglycerides (Tg) (r = 0.42; p = 0.01 and r = 0.48; p = 0.002, respectively) and triglycerides bind to VLDL (Tg-VLDL) (r = 0.40; p < 0.01 and r = 0.49; p = 0.002, respectively). When the cluster of metabolic syndrome was analyzed, SG was inversely related to uric acid levels and to the waist-hip index. However, SI was only related to the uric acid levels (r = 0.38; p = 0.01)., Conclusions: In non-obese, recently diagnosed hypertensive patients, the SG parameter seems to be an early marker for the development of metabolic syndrome.

We investigated the role of the beta-3-adrenergic receptor polymorphism in membrane lipid composition and erythrocyte membrane sodium transport in essential hypertensive patients. We studied 87 essential hypertensive patients determining: The Trp64Arg mutation of the beta-3-adrenergic receptor by PCR, lipoprotein profile by standard laboratory methods, membrane lipid composition by IATROSCAN and erythrocyte sodium lithium countertransport by Canessa technique. Patients with the mutation as compared with those without it showed lower membrane cholesterol, membrane cholesterol phospholipids ratio and erythrocyte sodium lithium countertransport, however blood pressure and the other studied variables were similar in both groups of patients. After adjusting by sex sodium lithium countertransport activity remained significant. These data suggest that although the Trp64Arg mutation of the beta-3-adrenergic receptor is related with a different membrane lipid composition and erythrocyte sodium lithium countertransport values it does not contribute to blood pressure levels in essential hypertensive patients.

Background: It has been reported the association between M235T angiotensinogen (AGT) and I/D angiotensin converting enzyme (ACE) gene polymorphisms and hypertension and other cardiovascular risk factors. However there are few data about Spanish population. So that we have studied the relationship among the aforementioned polymorphisms and hypertension and the possibility of association between any polymorphism and a worse cardiovascular risk profile., Patients and Methods: 251 hypertensive and 245 control normotensive subjects were studied. The M235T AGT and the I/D ACE gene polymorphisms were determined by polymerase chain reaction (PCR). Family and personal history of cardiovascular disease, lipoprotein profile, microalbuminuria and left ventricular hypertrophy (LVH) by Sokolow index were analyzed in hypertensive patients., Results: The distribution of the different polymorphisms was similar among hypertensive and normotensive subjects. There was not any relationship among AGT nor ACE genotypes and target organ damage. The II ACE genotype was associated with higher lipoprotein (a) (Lp[a]) levels and greater cerebrovascular disease family history and the MT AGT genotype with lower total cholesterol (TC) and triglycerides (TG) levels., Conclusions: In our study there was not any relationship between arterial hypertension and M235T AGT or I/D ACE gene polymorphisms. None specific genotype was associated with worse cardiovascular risk profile. The II ACE genotype was a predictor of cerebrovascular disease risk through higher levels of Lp(a) and the MT AGT genotype was associated with a better lipid profile.

Background: Porphyria cutanea tarda (PCT) is characterized by a deficiency of uroprophyrinogen decarboxylase (URO-D). The activity of this enzyme is decreased in the presence of iron-dependent disorders. A relationship between the hepatic hemosiderosis, which is present in most patients with PCT, and the status of the hemochromatosis gene has been observed. Particularly, two mutations of the gene have been described, one of them (Cys282Tyr) is related to the iron overload and might influence on the development of the clinical signs of PCT., Patients and Methods: We have measured the transferrin saturation percentage and observed the status of the hemochromatosis gene in a patient diagnosed with PCT and in five of their relatives., Results: The proband and one sister had a marked increase of uroporphyrins and iron overload, and both had the mutation Cys282Tyr, which was also present in the mother., Conclusions: This is the first study measuring iron overload and hemochromatosis gene mutations in relatives, and not in patients with PCT. We think that the study of this family justifies the systematic investigation of these parameters in all first degree relatives of patients with PCT, to identify subjects at risk, who can benefit from prophylactic measures and early therapy.

In essential hypertensive patients "exaggerated natriuresis" is a response to acute volume expansion. However, the underlying mechanisms for this remain to be determined. We studied 19 patients with essential hypertension (HP) and 9 normotensive subjects (NS). In all examined subjects the response to acute central volume expansion, without the plasma compositional change that Trendelenburg's position involves, was evaluated during 90 min (period T) after a similar period of deambulation (period D). Mean blood pressure (MBP), tubular sodium handling by the lithium clearance technique, plasma renin activity (PRA), plasma aldosterone (PA), plasma catecholamines and urine prostaglandine E2 and kallikrein were assessed after D and T. MBP was significantly higher in HP than in NS (p = 0.00001). HP showed "exaggerated natriuresis" after T (fractional excretion of sodium increased from 0.55 +/- 0.1% after D to 1.20 +/- 0.2% after T, p < 0.01). This was because of a decrease in their proximal fractional reabsorption of sodium (from 74.96 +/- 1.8% after D to 62.50 +/- 2.8% after T, p < 0.01). Plasma epinephrine and plasma dopamine after T were significantly lower than in standing position in HP (p < 0.01) but no in NS. The decrease in plasma renin activity after T in HP was 53%, and 32% in NS. There were not any significant differences between groups in the other neurohormonal systems studied. We conclude that the major determinant of "exaggerated natriuresis" in hypertensive patients is a higher stimulation of the cardiopulmonary receptors following Trendelenburg's position and consequently stronger reflex inhibition of sympathetic system activity and renin-angiotensin II activity. The "exaggerated natriuresis" after Trendelenburg's position in HP was an expression of abnormal pressure natriuresis.

Background: To characterize the possible existence of kinetic anomalies of four erythrocyte membrane sodium transport systems in a group of essential hypertensive patients, and to study the clinical and biochemical profile of those with anomalies., Methods: We studied 33 essential hypertensive patients and 33 normotensive controls. The kinetics (maximal rate and apparent dissociation constant for internal sodium) of Na(+)-K+ pump, Na(+)-K(+)-Cl- cotransport and Na(+)-Li+ countertransport was calculated after a sodium loading procedure, according to the methods of Garay; the passive Na+ permeability was also determined., Results: The studied kinetic parameters were not significantly different in both groups. Nevertheless, we found a group of hypertensive patients with some transport abnormalities: increased intracellular sodium (9.1%), accelerated Na+ passive permeability (9.1%), lower activity of the Na(+)-K+ pump (7.1%) and the Na(+)-K(+)-Cl- cotransport (4%) and an increased maximal rate of the Na(+)-Li+ countertransport (11.8%). Na+Li+ countertransport activity was statistically related to plasma levels of urea, creatinine, glucose and LDL-cholesterol, and the activity of the Na(+)-K(+)-Cl- cotransport was related to plasma uric acid. The hypertensive patients with sodium transport anomalies showed higher body mass index, uric acid plasma levels and atherogenic index than those without these kind of anomalies, and they also showed lowered HDL-cholesterol plasma levels., Conclusions: A small group of essential hypertensive patients (around 31%) show kinetic alterations of sodium transport systems. There is a relation between Na(+)-Li+ countertransport activity and some cardiovascular risk parameters. Hypertensive patients with transport anomalies are a group with an increased cardiovascular risk.

Background: With the aim of confirming the possible existence of an increase in the fractional proximal reabsorption of sodium in the development of essential hypertension, the tubular dynamics of sodium were compared by the lithium clearance technique in a group of hypertensive patients and controls., Methods: Following a week of drug suspension 186 patients with slight or moderate essential hypertension and 37 normal subjects with homogeneous sodium ingestion were studied. A clearing period of 90 minutes prior to the administration of a tracing doses of lithium was considered to calculate the fractional proximal and distal reabsorption of sodium in terms of glomerular filtration. In addition to global comparison of the measurements, the hypertensives were classified and compared according to mean arterial pressure (MAP) and percentages of plasma renin activity (PRA)., Results: No differences were found in tubular dynamics of sodium between hypertensive and normotensive patients. Neither did the degree of hypertension induce differences. However, upon classifying the patients according to PRA, it was found that those with PRA higher than 0.5 ng/ml-1/h-1 had less secondary natriuresis to a greater fractional distal reabsorption of sodium (p < 0.05)., Conclusions: The findings of the this study do not support the possible existence of a primary defect of the transport of sodium in the proximal tubule in the origin and/or maintenance of essential arterial hypertension.

We present three cases of Takayasu disease which were peculiar because all three of them first manifested as vasculorenal hypertension. The pathogenic mechanisms of hypertension in this disease are reviewed, being renal arteries stenosis the most important mechanism. The great prognostic and therapeutic implications of hypertension in these patients made us suggest the performance of arteriographies of supraaortic trunks in all cases of vasculorenal arterial hypertension associated to certain clinical, analytical and/or arteriographic criteria which are mentioned.

Background: The possible influence of the variations in blood pressure and the plasma renin activity (PRA) after the administration of nifedipine (NIF) on the natriuretic effect of this calcium antagonist were evaluated., Methods: The differences in the values of sodium excretion and tubular reabsorption were evaluated in 18 patients with essential hypertension with the method of the lithium clearance before and after the administration of a sublingual NIF dose., Results: An increase in sodium excretion at the expense of a smaller distal reabsorption was found after NIF administration, without differences in patients with (n = 9) or without (n = 9) increase in PRA after NIF administration. The differences in several parameters when patients were classified depending on whether their mean blood pressure was reduced (n = 8) in more than 10% or not (n = 10) 90 minutes after NIF administration are discussed., Conclusions: Natriuresis induced by nifedipine is due to a diminished distal reabsorption of sodium. This effect is independent of PRA or its changes. On the other hand, the differences found in subgroups with different blood pressure response support the hypothesis that there are two populations of patients with essential hypertension depending on their acute response to calcium antagonists.

We study the modifications of sodium tubular resorption, measured by lithium clearance after a single dosage of sublingual captopril, administered to 24 patients afflicted with nonfiltration after captopril produced an increase of proximal resorption of sodium, compensated by minor distal resorption, keeping a constant natriuresis. The different effects of captopril on blood pressure create 2 groups: a) patients who showed a decrease of blood pressure (n = 14), where a fall of distal resorption of sodium simultaneous with an increase of fractional sodium excretion was registered, and b) patients who did not experience changes in blood pressure nor changes after tubular function tests.