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Biomedical subjects

Pablo Stiefel

Publications and source records attributed to Pablo Stiefel.

10 recordsLinked to original sources
PubMed2005

Effects of short-term supplementation with folic acid on different oxidative stress parameters in patients with hypertension.

Oxidative stress seems to play an important role in the pathophysiology of essential hypertension. Due to its antioxidant features, we studied the protective action of folic acid in hypertensive patients, their food supplemented for 2 weeks with this vitamin. Several oxidative stress parameters were measured in the serum of these patients. The results show that folic acid supplementation improves levels of oxidative stress markers in individuals with hypertension, overall in those patients whose initial parameter values were highest.

Adult↗
PubMed2005

[Abnormal glycemic metabolism in essential hypertension. Role of the an oral glucose tolerance test].

BACKGROUND AND OBJECTIVE: There is a high prevalence of diabetes in essential hypertensive patients, hence increasing the cardiovascular risk of these subjects. Our aim was to test the importance of a routine assessment of an oral glucose tolerance test (OGTT) in a sample of recently diagnosed essential hypertensives. PATIENTS AND METHOD: We studied 270 recently diagnosed untreated hypertensives (56% males). We measured fasting lipids and plasma glucose and insulin at baseline and after OGTT. RESULTS: 38.5% of the studied subjects had any abnormality of glucose metabolism, glucose intolerance (22.2%) and type 2 diabetes (12.2%) being the most common. An impaired fasting glucose was present in 4.1% of subjects. Patients with intolerance or type 2 diabetes had a worse plasma lipid profile, and those with impaired fasting glucose, a higher HOMA index. CONCLUSIONS: The high incidence of glucidic abnormalities found in hypertensive patients signals a need to perform an OGTT test in them. This can lead to the implementation of strategies aimed at halting vascular impairment in hypertensives with type 2 diabetes and delay the development of type 2 diabetes in patients with glucose intolerance.

Adult↗
PubMed2004

Glucose effectiveness is strongly related to left ventricular mass in subjects with stage I hypertension or high-normal blood pressure.

BACKGROUND: Evidence suggests that "glucose effectiveness," (SG) or the effect of glucose per se to enhance net glucose disposal, may be at least as important as the insulin sensitivity index (SI) in the assessment of glucose tolerance. Our objective was to study the relationship of SG and SI parameters to left ventricular mass in a group of untreated, nondiabetic, and nonobese subjects recently diagnosed with stage I or high-normal blood pressure (BP). METHODS: In this sample of subjects, among whom the expected prevalence of insulin resistance is low, we assessed SG and SI parameters using the intravenous glucose tolerance test and minimal model analysis. We also measured left ventricular mass (LVM) index and diastolic function by echocardiography. RESULTS: We observed a strong relationship between SG and LVM index (r = -0.61, P <.0001). Patients with left ventricular hypertrophy (LVH) had lower SG than those without LVH (0.1114 +/- 0.04 v 0.2088 +/- 0.08 x 10(-1). min(-1), P <.001). In contrast, patients below the lowest quartile of the SG parameter distribution had higher LVM index (126.4 +/- 23.1 v 94.8 +/- 22.3 g/m(2), P <.001) and also had higher prevalence of LVH than the other patients (P <.0001). The SI related only to diastolic dysfunction, suggesting that SG may be an earlier marker of LVH than SI in hypertension. CONCLUSION: In this sample of nonobese and glucose-tolerant subjects with an early stage of hypertension, SG but not SI was related to LVM.

Adult↗
PubMed2002

[Genetic polymorphisms of the renin-angiotensin system and essential hypertension].

BACKGROUND: The renin-angiotensin system (RAS) is known to regulate the blood pressure (BP). Several RAS polymorphisms have been associated with essential hypertension (EH), but there is uncertainty about this association. We examined whether the insertion/deletion (I/D) polymorphism of the angiotensin converting enzyme (ACE) gene, and the M235T polymorphism of the angiotensinogen (AGT) gene were associated with EH in a sample of Spanish hipertensive patients. PATIENTS AND METHOD: We studied 1,204 patients with EH (BP > 140/90 mmHg): 668 males, aged 50.8 (13.6) years with systolic BP 151.7 (19.1) and diastolic BP 94.3 (13) mmHg [mean (SD)] and 536 females, aged 52.4 (13.9) years with systolic BP 155.1 (19.8) and diastolic BP 94.5 (12.3) mmHg. As a control group, 367 men and 280 women with no family history of cardiovascular disease who had a normal blood pressure were included. Polymorphisms were determined by PCR amplification of genomic DNA, followed by enzyme digestion for the AGT gene polymorphism. RESULTS: The genotype distribution and allele frequencies of the two RAS polymorphisms were similar in hypertensive and control subjects. Similarly, there were no differences in BP level with regard to the genotype in male or female patients. In addition, we did not find any compound effect of the I/D ACE gene and M235T AGT gene polymorphisms on BP levels in hypertensive subjects. CONCLUSIONS: This study suggests that in the population studied, the contribution of the ACE I/D polymorphism and the AGT M235T polymorphism in the development of EH is less important than previously estimated.

Female↗
PubMed2002

Simvastatin improves endothelial function in spontaneously hypertensive rats through a superoxide dismutase mediated antioxidant effect.

BACKGROUND: Hydroxymethylglutaryl coenzyme A (HMGCoA) reductase inhibitors have beneficial effects beyond their cholesterol-lowering properties. The antioxidant mechanism of HMGCoA reductase inhibitors is not completely understood. OBJECTIVES: To elucidate the antioxidant effect of simvastatin. METHODS: We studied the influence of simvastatin treatment on the development of hypertension, modification of antioxidant systems, and reactivity of aortic rings in Wistar-Kyoto (WKY) and spontaneously hypertensive (SHR) rats. RESULTS: Simvastatin had no effect on blood pressure (BP). Simvastatin treatment (either 1 or 2 mg/kg body weight for 12 or 20 weeks) increased superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities in SHR rats compared with untreated control SHR rats. Carbachol-induced relaxation of aortic rings was impaired in control SHR rats and was restored by simvastatin treatment. Addition of SOD improved the response in control SHR rats and did not have any effect in treated SHR rats. Addition of diethyldithiocarbamic acid, a selective inhibitor of SOD, produced a mild non-significant impairment in carbachol-induced relaxation in control SHR rats, suggesting a deficient antioxidant system in these animals. However, in treated SHR and in WKY rats, impairment of the relaxation was marked, implying that SOD activity in these animals was important to maintain endothelial function. In aortic rings without endothelium from SHR rats, contraction induced by free radicals was substantially higher than in WKY rats. This effect was attenuated in 1-mg-treated rats and abolished in 2-mg-treated rats. CONCLUSIONS: Simvastatin promotes intracellular antioxidant systems, fundamentally SOD, restoring endothelial function but not having any effect on blood pressure.

Animals↗
PubMed2002

Role of ketoconazole treatment in urinary-free cortisol-to-cortisone and tetrahydrocortisol-to-tetrahydrocortisone ratios in nonectopic Cushing's syndrome.

We hypothesized that in nonectopic Cushing syndrome there is an insufficient activity of type II (renal) 11beta-hydroxysteroid dehydrogenase (11beta-HSD2) that is related to cortisol excess, rather than to corticotropin (adrenocorticotropic hormone [ACTH]) levels. We measured plasma ACTH and urinary-free cortisol (UFF), urinary-free cortisone (UFE), tetrahydrocortisol (UTHF), and tetrahydrocortisone (UTHE) in 24-h urine samples of 24 healthy subjects and 15 patients diagnosed with nonectopic Cushing syndrome. Then, in the group of patients, a new 24-h urine sample was collected after treatment with 800 mg daily of ketoconazole. The UFF/UFE and UTHF/UTHE ratios were calculated as an estimation of 11beta-HSD2 activity. The patients had an increase in both the UFF/UFE (19.95 +/- 10.3 vs 5.78 +/- 4.72 nmol/24 h; p < 0.0001) and UTHF/UTHE ratios (5.36 +/- 5.23 vs 1.39 +/- 0.95 nmol/24 h; p < 0.001). Both UFF/UFE and UTHF/UTHE ratios decreased after ketoconazole treatment (19.95 +/- 10.3 vs 12.2 +/- 6.9 nmol/24 h; p < 0.005; and 5.36 +/- 5.23 vs 1.62 vs 1.21 nmol/24 h; p < 0.001, respectively). The control subjects had a significant relationship between UFF and UFE (r = 0.70, p < 0.0001), and between UTHF and UTHE (r = 0.75, p < 0.0001) that did not exist in the patient group. After ketoconazole treatment, the decrease in cortisol excretion in the patient group allowed a positive and significant relation between UFF and UFE (r = 0.64, p < 0.01) and between UTHF and UTHE (r = 0.56, p < 0.05) to appear. There was not any significant relationship between either UFF/UFE or UTHF/UTHE ratios and plasma levels of ACTH.

Adult↗