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1.
Sci Total Environ ; 575: 1203-1210, 2017 Jan 01.
Article in English | MEDLINE | ID: mdl-27697347

ABSTRACT

Knowledge of the arbuscular mycorrhizal fungal assemblages in the Trachypogon savanna ecosystems is very important to a better understanding of the ecological processes mediated by this soil microbial group that affects multiple ecosystem functions. Considering the hypothesis that the biocrusts can be linked to vegetation through the arbuscular fungi mycelial network, the objectives proposed in this study were to determine (i) whether there are arbuscular mycorrhizal fungi (AMF) in the biocrusts (ii) whether arbuscular mycorrhizal fungal assemblages are linked to the Trachypogon patches, and (iii) whether the composition of the assemblages is related to soil properties affected by microbiological activity. The community structure of the AMF was investigated in three habitats: rhizospheric soil and roots of Trachypogon vestitus, biological soil crusts, and bare soil. The canonical correspondence analysis showed that two soil properties related to enzymatic activity (protease and ß-glucosidase) significantly affected the community composition of the AMF. The biocrusts in the Venezuelan savanna are colonized by an AM fungal community linked to that of the bare soil and significantly different from that hosted by the roots of the surrounding T. vestitus, suggesting that assemblages of AMF in biocrusts might be related more closely to those of annual plant species appearing in favorable conditions.


Subject(s)
Grassland , Mycorrhizae , Poaceae , Soil Microbiology , Ecosystem , Plant Roots , Rhizosphere , Soil , Venezuela
2.
Blood Press ; 22(6): 362-70, 2013 Dec.
Article in English | MEDLINE | ID: mdl-23607284

ABSTRACT

Only 20-30% out of the treated hypertensive patients in Europe are achieving blood pressure (BP) control. Among other recognized factors, these poor results could be attributable to the fact that for many doctors it is very difficult to detect which is the predominant hemodynamic cause of the hypertension (hypervolemia, hyperinotropy or vasoconstriction). The aim of the study was to use non-invasive thoracic electrical bioimpedance (TEB) to evaluate hemodynamic modulators and subsequent hemodynamic status in uncontrolled hypertensive patients, receiving at least two antihypertensive drugs. A number of 134 uncontrolled hypertensive patients with essential hypertension were evaluated in nine European Hypertension Excellence centers by means of TEB (the HOTMAN(®) System). Baseline office systolic and diastolic BP averaged 156/92 mmHg. Hemodynamic measurements show that almost all patients (98.5%) presented at least one altered hemodynamic modulator: intravascular hypervolemia (96.4%) and/or hypoinotropy (42.5%) and/or vasoconstriction (49.3%). Eleven combinations of hemodynamic modulators were present in the study population, the most common being concomitant hypervolemia, hypoinotropy and vasoconstriction in 51(38%) patients. Six different hemodynamic states (pairs of mean arterial pressure and stroke index) were found. Data suggest that there is a strong relation between hypertension and abnormal hemodynamic modulators. This method might be helpful for treatment individualization of hypertensive patients.


Subject(s)
Antihypertensive Agents/therapeutic use , Hypertension/drug therapy , Hypertension/metabolism , Blood Pressure Determination , Blood Pressure Monitoring, Ambulatory/methods , Essential Hypertension , Female , Hemodynamics , Humans , Hypertension/physiopathology , Male
3.
Cerebrovasc Dis ; 34(4): 290-6, 2012.
Article in English | MEDLINE | ID: mdl-23128470

ABSTRACT

Intima-media thickness (IMT) provides a surrogate end point of cardiovascular outcomes in clinical trials evaluating the efficacy of cardiovascular risk factor modification. Carotid artery plaque further adds to the cardiovascular risk assessment. It is defined as a focal structure that encroaches into the arterial lumen of at least 0.5 mm or 50% of the surrounding IMT value or demonstrates a thickness >1.5 mm as measured from the media-adventitia interface to the intima-lumen interface. The scientific basis for use of IMT in clinical trials and practice includes ultrasound physics, technical and disease-related principles as well as best practice on the performance, interpretation and documentation of study results. Comparison of IMT results obtained from epidemiological and interventional studies around the world relies on harmonization on approaches to carotid image acquisition and analysis. This updated consensus document delineates further criteria to distinguish early atherosclerotic plaque formation from thickening of IMT. Standardized methods will foster homogenous data collection and analysis, improve the power of randomized clinical trials incorporating IMT and plaque measurements and facilitate the merging of large databases for meta-analyses. IMT results are applied to individual patients as an integrated assessment of cardiovascular risk factors. However, this document recommends against serial monitoring in individual patients.


Subject(s)
Carotid Arteries/pathology , Carotid Intima-Media Thickness , Stroke/pathology , Cardiovascular Diseases/diagnostic imaging , Cardiovascular Diseases/etiology , Cardiovascular Diseases/pathology , Carotid Arteries/diagnostic imaging , Humans , Plaque, Atherosclerotic/diagnosis , Plaque, Atherosclerotic/diagnostic imaging , Randomized Controlled Trials as Topic , Risk Assessment , Risk Factors , Stroke/diagnostic imaging
4.
Appl Opt ; 49(36): 6903-9, 2010 Dec 20.
Article in English | MEDLINE | ID: mdl-21173824

ABSTRACT

We present a novel method for the efficient generation of even, odd, and helical Mathieu-Gauss beams of arbitrary order and ellipticity by means of a phase-only spatial light modulator (SLM). Our method consists of displaying the phase of the desired beam in the SLM; the reconstructed field is obtained on-axis following a spatial filtering process with an annular aperture. The propagation invariance and topological properties of the generated beams are investigated numerically and experimentally.

5.
Nutr. hosp ; 25(5): 832-837, sept.-oct. 2010. tab
Article in Spanish | IBECS | ID: ibc-97308

ABSTRACT

Objetivo: evaluar la asociación entre el estado nutricional antropométrico materno durante su tercer trimestre de gravidez con el estado nutricional antropométrico del neonato. Método: Se evaluaron 98 binomios madre-recién nacido atendidos en el Hospital Público Universitario de Caracas y en el Hospital Privado de Clínicas Caracas, Venezuela. Las variables maternas fueron: peso pregestacional, peso gestacional, talla, circunferencia media del brazo (CMB), circunferencia de pantorrilla y pliegue del tríceps y se construyeron los indicadores antropométricos: índice de masa corporal pregestacional (IMCpg) y gestacional (IMCg), así como indicadores de composición corporal: área grasa (AG) y muscular del brazo (AM). En el recién nacido, se evaluó: peso, talla, índice ponderal (IP), y evaluación clínica del estado nutricional del neonato (ECEN). Resultados: El IMCg mostró una de las mejores correlaciones y con significancia estadística con el IP del neonato (r=0,22) observando este mismo resultado la CMB materno con el IP (r=0,21) y el puntaje de ECEN (r=0,22). En cuanto a los indicadores de composición corporal materno, únicamente se encontró correlación positiva y estadísticamente significativas entre el AM y el puntaje ECEN (r = 0,24) y el AG con el IP (r = 0,20). Conclusión: La CMB materna podría constituir una variable indicativa del estado nutricional del neonato y se recomienda la incorporación temprana en el monitoreo rutinario del control prenatal (AU)


The objective of the present study was to evaluate the association between the anthropometric nutritional state of the pregnant women during his third trimester of pregnancy with the anthropometric state nutritional of the product of the gestation, who carried out their prenatal control in the University Hospital of Caracas and the Hospital of Caracas Clinics. The evaluated variables were: pregestacional weight, gestacional weight, chart, average circumference of the arm and fold of tríceps; the anthropometric indicators were constructed: index of corporal mass (IMC) pregestacional and gestacional and of corporal composition such as greasy and muscular area of the arm. In new born, one evaluated the weight and the stature and so the ponderal index was constructed (IP), as well as the clinical evaluation of the nutritional state of the neoborn one (ECEN). Statistical Package SPSS 13,0 for Windows, calculating statistical descriptive basic and coefficient of correlation of Pearson was used (p 0.05). The results indicate that when considering the associations between the maternal variables and anthropometric indicators with the neonatal ones is to a great extent positive correlation, of this form, cases as the average circumference of arm (CMB) maternal were statistically significant with the ponderal index and puntaje ECEN, indicating that the maternal CMB is constituted like an indicative variable of the nutritional state of the neoborn one. The early incorporation in the routine monitoring of the prenatal control, the anthropometric valuation with effective simple variables of low cost is recommended and, being able to detect nutritional alterations in which it is found opportunely to prevent adverse results in the neoborn one (AU)


Subject(s)
Humans , Male , Female , Infant, Newborn , Nutritional Status , Maternal Nutrition , Birth Weight , Body Weights and Measures/statistics & numerical data , Nutrition Assessment , Weight by Height
6.
Nutr Hosp ; 25(5): 832-7, 2010.
Article in Spanish | MEDLINE | ID: mdl-21336443

ABSTRACT

The objective of the present study was to evaluate the association between the anthropometric nutritional state of the pregnant women during his third trimester of pregnancy with the anthropometric state nutritional of the product of the gestation, who carried out their prenatal control in the University Hospital of Caracas and the Hospital of Caracas Clinics. The evaluated variables were: pregestational weight, gestational weight, chart, average circumference of the arm and fold of triceps; the anthropometric indicators were constructed: index of corporal mass (IMC) pregestational and gestational and of corporal composition such as greasy and muscular area of the arm. In new born, one evaluated the weight and the stature and so the ponderal index was constructed (IP), as well as the clinical evaluation of the nutritional state of the newborn one (ECEN). Statistical Package SPSS 13,0 for Windows, calculating statistical descriptive basic and coefficient of correlation of Pearson was used (p 0.05). The results indicate that when considering the associations between the maternal variables and anthropometric indicators with the neonatal ones is to a great extent positive correlation, of this form, cases as the average circumference of arm (CMB) maternal were statistically significant with the ponderal index and puntaje ECEN, indicating that the maternal CMB is constituted like an indicative variable of the nutritional state of the newborn one. The early incorporation in the routine monitoring of the prenatal control, the anthropometric valuation with effective simple variables of low cost is recommended and, being able to detect nutritional alterations in which it is found opportunely to prevent adverse results in the newborn one.


Subject(s)
Nutritional Status , Pregnancy Outcome/epidemiology , Adiposity , Adult , Anthropometry , Arm/anatomy & histology , Birth Weight , Female , Gestational Age , Humans , Infant, Newborn , Muscle, Skeletal/anatomy & histology , Pregnancy , Venezuela/epidemiology
7.
Cerebrovasc Dis ; 23(1): 75-80, 2007.
Article in English | MEDLINE | ID: mdl-17108679

ABSTRACT

Intima-media thickness (IMT) is increasingly used as a surrogate end point of vascular outcomes in clinical trials aimed at determining the success of interventions that lower risk factors for atherosclerosis and associated diseases (stroke, myocardial infarction and peripheral artery diseases). The necessity to promote further criteria to distinguish early atherosclerotic plaque formation from thickening of IMT and to standardize IMT measurements is expressed through this updated consensus. Plaque is defined as a focal structure that encroaches into the arterial lumen of at least 0.5 mm or 50% of the surrounding IMT value or demonstrates a thickness >1.5 mm as measured from the media-adventitia interface to the intima-lumen interface. Standard use of IMT measurements is based on physics, technical and disease-related principles as well as agreements on how to perform, interpret and document study results. Harmonization of carotid image acquisition and analysis is needed for the comparison of the IMT results obtained from epidemiological and interventional studies around the world. The consensus concludes that there is no need to 'treat IMT values' nor to monitor IMT values in individual patients apart from exceptions named, which emphasize that inside randomized clinical trials should be performed. Although IMT has been suggested to represent an important risk marker, according to the current evidence it does not fulfill the characteristics of an accepted risk factor. Standardized methods recommended in this consensus statement will foster homogenous data collection and analysis. This will help to improve the power of randomized clinical trials incorporating IMT measurements and to facilitate the merging of large databases for meta-analyses.


Subject(s)
Carotid Arteries/diagnostic imaging , Carotid Artery Diseases/diagnostic imaging , Tunica Intima/diagnostic imaging , Tunica Media/diagnostic imaging , Adult , Aged , Cardiovascular Diseases/etiology , Carotid Artery Diseases/complications , Clinical Trials as Topic/methods , Humans , Image Interpretation, Computer-Assisted , Middle Aged , Research Design , Risk Factors , Ultrasonography/methods , Ultrasonography/standards
8.
Nutr Hosp ; 20(5): 358-63, 2005.
Article in Spanish | MEDLINE | ID: mdl-16229405

ABSTRACT

Equations to predict height from several body segments have been developed. However, those that use the knee height are limited by the need of an instrument with high cost (anthropometer). Thus, the aim of this study was to develop a prediction equation from the leg length by using a tape measure. Leg length and height was measured in 180 subjects, with ages 30-59 years that attended the Ambulatorio Docente Asistencial of the University Hospital of Caracas, from April to June of 2002. In order to determine the correlation degree of each measurement with height, the existent correlation between height and each one of the studied variables (leg length, sex, age) and between the variables to one each other was calculated by means of the Pearson's correlation coefficient. Linear regression analysis was done to estimate the height in each gender and the results were tested on an independent sample. The generated equations achieved a very good correlation with the real height and the standard error was calculated. Thus, in those subjects in whom assessment of the real height is not possible by conventional means, it is possible to use height prediction equations from simple techniques and equipment accessible to the whole health care staff.


Subject(s)
Body Height , Leg/anatomy & histology , Adult , Age Factors , Female , Humans , Linear Models , Male , Middle Aged , Sex Factors , Weights and Measures
9.
Cerebrovasc Dis ; 18(4): 346-9, 2004.
Article in English | MEDLINE | ID: mdl-15523176

ABSTRACT

Intima-media thickness (IMT) is increasingly used in clinical trials as a surrogate end point for determining the success of interventions that lower risk factors for atherosclerosis. The necessity for unified criteria to distinguish early atherosclerotic plaque formation from thickening of IMT and to standardize IMT measurements is addressed in this consensus statement. Plaque is defined as a focal structure that encroaches into the arterial lumen of at least 0.5 mm or 50% of the surrounding IMT value or demonstrates a thickness of > or =1.5 mm as measured from the media-adventitia interface to the intima-lumen interface. Standard use of IMT measurements is recommended in all epidemiological and interventional trials dealing with vascular diseases to improve characterization of the population investigated. The consensus concludes that there is no need to 'treat IMT values' nor to monitor IMT values in individual patients apart from few exceptions. Although IMT has been suggested to represent an important risk marker, it does not fulfill the characteristics of an accepted risk factor. Standardized methods recommended in this consensus statement will foster homogenous data collection and analysis. This will help to improve the power of studies incorporating IMT measurements and to facilitate the merging of large databases for meta-analyses.


Subject(s)
Carotid Arteries/diagnostic imaging , Tunica Intima/diagnostic imaging , Tunica Media/diagnostic imaging , Ultrasonography/standards , Arteriosclerosis/diagnostic imaging , Humans
10.
J Hum Hypertens ; 16 Suppl 1: S13-7, 2002 Mar.
Article in English | MEDLINE | ID: mdl-11986886

ABSTRACT

Dopamine, a neurotransmitter, precursor of noradrenaline, is responsible for cardiovascular and renal actions, such as increase in myocardial contractility and cardiac output, without changes in heart rate, producing passive and active vasodilatation, diuresis and natriuresis. These cardiovascular and renal actions take place through the interaction with dopamine receptors, D(1), D(2), D(3), D(4), and D(5). Recent findings point to the possibility of D(6) and D(7)receptors. Dopamine is known to influence the control of arterial pressure by influencing the central and peripheral nervous system and target organs such as kidneys and adrenal glands, in some types of hypertension. Although dopamine and its derivatives have been shown to have antihypertensive effects, these are still being studied; therefore it is important to explain some physiological and pharmacological aspects of dopamine, its receptors, and the clinical uses it could have in the treatment of arterial hypertension and more recently in obesity, based on evidence proving a clear association between obesity and the decrease in the expression of D(2) receptors in the brain of obese persons.


Subject(s)
Dopamine/pharmacology , Hypertension/metabolism , Hypertension/physiopathology , Obesity/metabolism , Obesity/physiopathology , Receptors, Dopamine/physiology , Angiotensin II/metabolism , Animals , Dopamine Agonists/pharmacology , Humans , Hypertension/etiology , Nitric Oxide/metabolism , Obesity/complications , Protein Kinase C/metabolism , Rats , Risk Factors , Sodium-Hydrogen Exchangers/metabolism , Vasopressins/metabolism
11.
J Hum Hypertens ; 16 Suppl 1: S93-9, 2002 Mar.
Article in English | MEDLINE | ID: mdl-11986904

ABSTRACT

Angiotensin II receptor blockers represent a class of effective and well tolerated orally active antihypertensive drugs. Activation of AT(1) receptors leads to vasoconstriction, stimulation of the release of catecholamines and antidiuretic hormone and promote growth of vascular and cardiac muscle. AT(1) receptor blockers antagonise all those effects. Losartan was the first drug of this class marketed, shortly followed by valsartan, irbesartan, telmisartan, candesartan, eprosartan and others on current investigation. All these drugs have the common properties of blockading the AT(1) receptor thereby relaxing vascular smooth muscle, increase salt excretion, decrease cellular hypertrophy and induce antihypertensive effect without modifying heart rate or cardiac output. Most of the AT(1) receptor blockers in use controlled blood pressure during the 24 h with a once-daily dose, without evidence of producing tolerance to the antihypertensive effect and being with low incidence of side effects even at long term use. Monotherapy in mild-to-moderate hypertension controls blood pressure in 40 to 50% of these patients; when a low dose of thiazide diuretic is added, 60-70% of patients are controlled. The efficacy is similar to angiotensin-converting enzyme (ACE) inhibitors, diuretics, calcium antagonists and beta-blocking agents. AT(1) receptor blockers are specially indicated in patients with hypertension who are being treated with ACE inhibitors and developed side effects such as, cough or angioedema. The final position in the antihypertensive therapy in this special population and other clinical situations, such as left ventricular hypertrophy, heart failure, diabetes mellitus and renal disease, has to be determined in large prospective clinical trials, some of which are now being conducted and seem promising.


Subject(s)
Angiotensin Receptor Antagonists , Antihypertensive Agents/therapeutic use , Hypertension/drug therapy , Animals , Antihypertensive Agents/pharmacokinetics , Humans , Receptors, Angiotensin/metabolism , Renin-Angiotensin System/drug effects
12.
J Hum Hypertens ; 16 Suppl 1: S114-7, 2002 Mar.
Article in English | MEDLINE | ID: mdl-11986907

ABSTRACT

Calcium antagonists represent an important group of drugs for the treatment of hypertension; they are effective in the whole range of severity of the disease. Dihy- dropyridine derivatives are most frequently used, and can be used in association with other antihypertensive drugs; meanwhile phenylalkylamines and benzothiazepines are contraindicated in association with beta-blocker drugs. Calcium antagonists with slow starting effect and long duration of action are the choice for use in long-term antihypertensive treatment. This group of drugs is specially indicated in elderly patients, in those with diabetes mellitus and in patients with coronary heart disease. Phenylalkylamines and benzothiazepine derivatives are also used in patients with supraventricular arrhythmias. This group of agents is as safe as diuretics, angiotensin-converting enzyme-inhibitors and beta-blocking drugs in the long-term treatment of hypertension.


Subject(s)
Calcium Channel Blockers/therapeutic use , Hypertension/drug therapy , Humans
13.
J Hum Hypertens ; 16 Suppl 1: S142-4, 2002 Mar.
Article in English | MEDLINE | ID: mdl-11986913

ABSTRACT

The objective of this study was to assess the pharmacokientic parameters of regular nimodipine (Bayer), 30 mg, given every 6 h and nimodipine AP (nimodipine in micro particles with programmed action contained in tablets, developed by Biocontrolled-Leti Group Laboratories), 120 mg, given every 24 h. Subjects (19 healthy volunteers, five female; 14 male: age: 21 +/- 0.7 years) received one formulation over 5 days. Then, after a washout period of 7 days, the other formulation was given. The analyst was blinded to the relationship in formulation received. Antecubital blood samples were taken before the first tablet was taken and after 15, 45, 60 min and 2, 4, 6, 8, 12, 13, 18 and 24 h on day 1 and five of each formulation. Nimodipine blood levels were analysed by HPLC. At steady-state regular nimodipine reached a C-max of 10.208 +/- 0.317 ng/ml, at a t-max of 1 h; minimum concentration 6 h after dosage was 1.2929 +/- 0.411 ng/ml, half-life was estimated in 2.9 h. Meanwhile nimodipine AP 120 mg reach a C-max of 11.885 +/- 0.403 ng/ml; a t-max of 1 h with a minimum concentration 24 h after the last dose of 4.2387 +/- 0.353 ng/ml (P < 0.001). Apparent half-life was calculated in 17.8 h (P < 0.001). Area under the curve for the 24 h period was 143.76 ng/ml/min for regular nimodipine and 183.7 ng/ml/min for nimodipine AP 120 mg (P < 0.001), indicating better bioavailability. In conclusion nimodipine in AP formulation 120 mg produced similar peak plasma levels (C-max) than regular nimodipine, but with higher trough (C-min) values and stable plasma levels with one administration every 24 h. This formulation would be more suitable when nimodipine chronic therapy is indicated.


Subject(s)
Calcium Channel Blockers/pharmacokinetics , Nimodipine/pharmacokinetics , Adult , Area Under Curve , Biological Availability , Calcium Channel Blockers/chemistry , Female , Humans , Male , Nimodipine/chemistry , Tablets
14.
Int J Clin Pharmacol Ther ; 39(8): 325-30, 2001 Aug.
Article in English | MEDLINE | ID: mdl-11515706

ABSTRACT

OBJECTIVE: The main objective of this study was to evaluate well-being and physical activity of 248 hypertensive patients, including 177 females, who had previously been included in the Latin-American Study on Lacidipine in Hypertension (LASTLHY). SUBJECTS, MATERIALS AND METHODS: This open study was carried out in 12 clinical centers in Argentina, Brazil, Colombia, Mexico and Venezuela, to compare, over a period of 16 weeks, the antihypertensive action of a fixed-dose, once daily of 4 mg lacidipine administered orally to 120 patients and 30 mg nifedipine GITS (Gastro-Intestinal Therapeutic System) administered to 128 patients, aged between 40 and 65 years. All patients had mild to moderate hypertension and treatment was begun at the end of a one-week placebo run-in period (end of week -1). Well-being and physical activity were assessed by means of single questionnaire, which reflected the physical and cultural diversities amongst the clinical centers and patients. The questionnaire included 13 multiple-choice and 8 contingent open questions. The score of each question was multiplied by a coefficient related to the importance of each question to the patient (semipersonalization); the coefficient was obtained from cultural and socioeconomic data collected at the time of enrollment. The semipersonalization was carried out by a blind psychological study with respect to the medication and had a high repeatability in the assignment of personalized coefficients to the score of each question. The scores of each question were added to obtain an overall well-being and activity scoring. The possible theoretical range for the overall scoring in this study was 10 - 124. RESULTS: See Table 1. CONCLUSION: The study revealed that the administration of calcium channel blockers such as lacidipine and nifedipine GITS, and lacidipine in particular, produced low incidence of side effects, and lacidipine in particular induced significant improvement in the quality of life.


Subject(s)
Antihypertensive Agents/therapeutic use , Calcium Channel Blockers/therapeutic use , Dihydropyridines/therapeutic use , Hypertension/drug therapy , Hypertension/psychology , Nifedipine/therapeutic use , Quality of Life , Activities of Daily Living , Administration, Oral , Adult , Aged , Exercise , Female , Health Surveys , Humans , Male , Middle Aged , Psychometrics
15.
J Hum Hypertens ; 14 Suppl 1: S2-5, 2000 Apr.
Article in English | MEDLINE | ID: mdl-10854072

ABSTRACT

Since 1950 all countries of the Latin-American subcontinent have experienced very important changes in several health indicators, in the demographic, epidemiological, socio-cultural and way of living profiles. The proportion of the population over 65 years old tend to be low in the Latin American countries in contrast to developed countries. Cardiovascular diseases are the main cause of death in most of the Latin American countries at a similar rate to that of the developed world. As infectious diseases are reduced, cardiovascular diseases takes their place as the main cause of death in Latin American countries. Prevalence of hypertension in different reports show variations from 40 to 8% in the adult population, but on average 20 to 23% of the adult population have elevated blood pressure. This prevalence is similar to reports in the developed world. However there is considerable variability in each country and its regions so it is important that local studies of prevalence and local factors in the development of hypertension are investigated. The degree of awareness, treatment and control of hypertension is lower than that reported in the developed world, and it is important to establish programmes to attend to this public health problem, from prevention to treatment, from primary care to higher levels of attention.


Subject(s)
Health Status , Hypertension/epidemiology , Public Health/standards , Age Factors , Cause of Death , Humans , Hypertension/complications , Hypertension/therapy , Latin America/epidemiology , National Health Programs/standards , National Health Programs/trends , Prevalence , Risk Factors , Stroke/epidemiology , Stroke/etiology , Stroke/prevention & control , Survival Rate
16.
J Hum Hypertens ; 14 Suppl 1: S69-72, 2000 Apr.
Article in English | MEDLINE | ID: mdl-10854084

ABSTRACT

Angiotensin II receptor antagonists (AT-1) represent a new group of orally active antihypertensive agents. Activation on AT-1 receptor leads to vasoconstriction, stimulation of the release of catecholamines and antidiuretic hormone with production of thirst, and promote growth of vascular and cardiac muscle; these effects are blocked by AT-1 antagonist agents. The first chemically useful, orally active AT-1 receptor antagonist was losartan, followed by other agents currently in clinical use, such as: valsartan, eprosartan, irbesartan, telmisartan, candesartan, and many others under investigation. AT-1 receptor antagonists are effective in reducing high blood pressure in hypertensive patients. Monotherapy in mild to moderate hypertension controls blood pressure in 40 to 50% of these patients; when a low dose of a thiazide diuretic is added, 60 to 70% of patients are controlled. The efficacy is similar to angiotensin-converting enzyme inhibitors, diuretics, calcium antagonists and beta-blocking agents. Tolerability has been reported to be very good. AT-1 receptor antagonists would be a drug of choice in otherwise well-controlled hypertensive patients treated with angiotensin-converting enzyme inhibitors who developed cough or angioedema. The final position in the antihypertensive therapy in this special population and other clinical situations, such as left ventricular hypertrophy, heart failure, diabetes mellitus and renal disease, has to be determined in large prospective clinical trials, some of which are now being conducted.


Subject(s)
Angiotensin Receptor Antagonists , Antihypertensive Agents/therapeutic use , Hypertension/drug therapy , Antihypertensive Agents/pharmacokinetics , Blood Pressure/drug effects , Humans , Hypertension/complications , Hypertension/metabolism , Hypertrophy, Left Ventricular/etiology , Hypertrophy, Left Ventricular/metabolism , Hypertrophy, Left Ventricular/prevention & control , Losartan/pharmacokinetics , Losartan/therapeutic use , Receptor, Angiotensin, Type 1 , Receptor, Angiotensin, Type 2 , Receptors, Angiotensin/metabolism , Treatment Outcome
17.
J Hum Hypertens ; 14 Suppl 1: S91-5, 2000 Apr.
Article in English | MEDLINE | ID: mdl-10854087

ABSTRACT

With the aim of evaluating the effects on blood pressure, platelet function and insulin sensitivity of the dihydropiridines lacidipine and nifedipine GITS, a parallel double-blind study was carried out in a group of 20 patients with mild to moderate essential hypertension. They received a placebo for 4 weeks; then were divided at random into two groups of 10 patients each. Nifedipine GITS, 30 mg and lacidipine, 4 mg, were given during 16 weeks of active treatment. Blood pressure and heart rate were measured at the clinic in supine, sitting and standing positions, 24 +/- 1 h after the last dose. After the placebo and active phases were carried out, a platelet aggregation test was performed to determine platelet malondialdehyde production and a tolerance to 100 g of glucose by measuring glucaemia and plasma insulin. Both drugs reduced systolic and diastolic blood pressure at the same level, however there were observable differences in the rate of reduction. The nifedipine GITS reduced supine systolic blood pressure by 25 mm Hg in the first week, while the lacidipine did so by 11 mm Hg. At the end of the study period nifedipine reduced supine systolic blood pressure by 28 mm Hg and lacidipine by 20 mm Hg. Heart rate was increased slightly but significantly in the nifedipine GITS group only in the standing position. Both drugs reduced platelet aggregation ex vivo only marginally but they modified the malondialdehyde production, indicating an action on the arachidonic acid metabolic pathway.


Subject(s)
Blood Platelets/physiology , Calcium Channels/therapeutic use , Dihydropyridines/therapeutic use , Hypertension/blood , Nifedipine/therapeutic use , Platelet Aggregation/drug effects , Arachidonic Acid/metabolism , Biomarkers/blood , Blood Platelets/drug effects , Blood Pressure/drug effects , Female , Heart Rate/drug effects , Humans , Hypertension/drug therapy , Male , Malondialdehyde/metabolism , Middle Aged , Posture/physiology , Single-Blind Method
18.
Int J Clin Pharmacol Ther ; 37(7): 323-31, 1999 Jul.
Article in English | MEDLINE | ID: mdl-10442506

ABSTRACT

OBJECTIVE: The aim of this study was to compare the effect of amlodipine and enalapril on platelet aggregation, and platelet production of malondialdehyde in patients with mild to moderate arterial hypertension. PATIENTS AND METHODS: A parallel, double-blind, placebo-controlled study was carried out in 24 patients (2 groups of 12 patients each). Initially all patients received placebo for four weeks; then amlodipine, 5 mg daily or enalapril 20 mg daily taken once a day at 7 am. Dosage was doubled after 4 weeks when diastolic blood pressure was > 90 mmHg in sitting position, the treatment was continued for 12 weeks. At the end of placebo and active phases a platelet aggregation test, using adenosine diphosphate, collagen and adrenaline, and a platelet malondialdehyde production test, either in basal conditions (MDA-basal) and after the stimulation of arachidonic acid pathway by adding ethylmaleimide (MDA-activated) were carried out. RESULTS: Blood pressure was reduced by both agents, enalapril and amlodipine. Enalapril controlled 58.3% of hypertensive patients with an average dosage of 31.7 mg/daily. Amlodipine controlled 75% of patients with a dosage of 7.1 mg/daily. Platelet aggregation was reduced by amlodipine in 15.9% for ADP (10 microM); 17.4% for collagen (2 microg/ml) and 19.9% for adrenaline (2 microM) (p < 0.025). Meanwhile enalapril slightly increased platelet aggregation by 6.7%, 1.3% and 5.6% for the three agents, respectively (p > 0.05, ns). Malondialdehyde was reduced by amlodipine in 45.33% (p < 0.05) for MDA-basal; 3.76% (p > 0.05) for MDA-activated; and the ratio MDA-basal:MDA-activated in 36.79% (p < 0.005). Meanwhile enalapril increased MDA-basal in 2.89%; MDA-activated in 3.58% and reduced the ratio MDA-basal:MDA-activated, in 10.34% (p > 0.05). CONCLUSION: Both agents, enalapril and amlodipine, reduced blood pressure, but only amlodipine reduced platelet aggregation and platelet production of malondialdehyde, indicating its action on the arachidonic acid metabolic pathway.


Subject(s)
Amlodipine/therapeutic use , Angiotensin-Converting Enzyme Inhibitors/therapeutic use , Calcium Channel Blockers/therapeutic use , Enalapril/therapeutic use , Platelet Aggregation Inhibitors/therapeutic use , Platelet Aggregation/drug effects , Amlodipine/pharmacology , Angiotensin-Converting Enzyme Inhibitors/pharmacology , Calcium Channel Blockers/pharmacology , Double-Blind Method , Enalapril/pharmacology , Female , Humans , Hypertension/drug therapy , Male , Malondialdehyde/metabolism , Middle Aged , Platelet Aggregation Inhibitors/pharmacology , Platelet Function Tests
19.
Arch Latinoam Nutr ; 49(4): 344-50, 1999 Dec.
Article in Spanish | MEDLINE | ID: mdl-10883299

ABSTRACT

The frame size improves the interpretation of the body mass in adult and its incorporation is very useful in the assessment of nutritional status. This study compared two of the anthropometric methods used to classify individuals according to frame size: Grant method (height (cm)/wrist circumference (cm)) and Frame index 2 (elbow breadth (mm)/height (cm) x 100) in order to identify coincidence, concordance and divergence between then. Data from two hundred and forty nine apparently healthy individuals, between the ages of 22 and 63, belonging to "Health Project: Administration employees of the Simón Bolívar University" were included. Results showed significant differences between the two methods, not only in the proportion of classified individuals in each frame size category, but also when contrasted the same method using one or another body hemispheres. When studying both methods, the divergence in frame size identification varied between 19% and 55% with a low concordance (k = < or = 0.40). Grant method, compared to Frame index 2 showed a greater association with the variables and indicators of total body mass and body fat; in the other hand, Frame index 2 revealed a lesser correlation with such variables and indicators specially in female (r = 0.17 with fat percentage). These results clearly show the differences that could be created in the frame size identification of an individual of group of individuals if different criteria are used; this could also lead to a wrong anthropometric diagnosis.


Subject(s)
Adipose Tissue , Anthropometry/methods , Body Composition , Adult , Body Height , Body Mass Index , Body Weight , Female , Humans , Male , Middle Aged , Venezuela
20.
Arch Latinoam Nutr ; 48(1): 13-7, 1998 Mar.
Article in Spanish | MEDLINE | ID: mdl-9754399

ABSTRACT

The present study is to analyze the concordance, agreements and divergence of anthropometry nutritional classification of weight-height (WH) in adults, using criteria that include frame size adjustments and no adjustment at all. 224 adults were studied (127 female and 117 males) from the "Simón Bolívar" University Administrative Employees Health Project, 1993. Using as basis, the variables weight, height, wrist circumference and elbow breadth, we determined: a) frame size by wrist circumference methods (WC) (Grant, 1980) and elbow breadth (EB) (Frame index 2 by Frisancho, 1989); b) classification by weight-height (WH) according to table by frame size (Frisancho, 1984). 57%, 38% and 6% corresponded to small, medium and large frame sizes, by WC. 16%, 60% and 25% by EB. When classifying by WH those results showed differences between 16-25% in female and 15-21% in males. When contrasting the three criteria, it was observed a bigger coincidence between WH without frame size adjustment and WH adjustment by EB. The smallest coincidence between WH adjusted by WC method and weight height without frame size adjustment in the whole group, while male and female got the biggest coincidence in WH adjustment by WC and HW without frame size adjustment. The smallest concordance (k = 0.37) was obtained when contrasting WH frame size adjustment by EB vs weight-height without adjustment in female, and biggest concordance (k = 0.60) when contrasting WH by WC and without adjustment in males. This results show that, there are significative differences in nutritional classification of weight-height in adults adjusted and non adjusted by frame size within the same group of persons.


Subject(s)
Anthropometry/methods , Body Height , Body Weight , Nutritional Status , Adult , Female , Humans , Male , Middle Aged , Reference Standards , Sex Factors
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