RESUMO
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.
Assuntos
Pradaria , Micorrizas , Poaceae , Microbiologia do Solo , Ecossistema , Raízes de Plantas , Rizosfera , Solo , VenezuelaRESUMO
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.
Assuntos
Estado Nutricional , Resultado da Gravidez/epidemiologia , Adiposidade , Adulto , Antropometria , Braço/anatomia & histologia , Peso ao Nascer , Feminino , Idade Gestacional , Humanos , Recém-Nascido , Músculo Esquelético/anatomia & histologia , Gravidez , Venezuela/epidemiologiaRESUMO
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.
Assuntos
Estatura , Perna (Membro)/anatomia & histologia , Adulto , Fatores Etários , Feminino , Humanos , Modelos Lineares , Masculino , Pessoa de Meia-Idade , Fatores Sexuais , Pesos e MedidasRESUMO
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.
Assuntos
Dopamina/farmacologia , Hipertensão/metabolismo , Hipertensão/fisiopatologia , Obesidade/metabolismo , Obesidade/fisiopatologia , Receptores Dopaminérgicos/fisiologia , Angiotensina II/metabolismo , Animais , Agonistas de Dopamina/farmacologia , Humanos , Hipertensão/etiologia , Óxido Nítrico/metabolismo , Obesidade/complicações , Proteína Quinase C/metabolismo , Ratos , Fatores de Risco , Trocadores de Sódio-Hidrogênio/metabolismo , Vasopressinas/metabolismoRESUMO
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.
Assuntos
Antagonistas de Receptores de Angiotensina , Anti-Hipertensivos/uso terapêutico , Hipertensão/tratamento farmacológico , Animais , Anti-Hipertensivos/farmacocinética , Humanos , Receptores de Angiotensina/metabolismo , Sistema Renina-Angiotensina/efeitos dos fármacosRESUMO
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.
Assuntos
Bloqueadores dos Canais de Cálcio/uso terapêutico , Hipertensão/tratamento farmacológico , HumanosRESUMO
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.
Assuntos
Bloqueadores dos Canais de Cálcio/farmacocinética , Nimodipina/farmacocinética , Adulto , Área Sob a Curva , Disponibilidade Biológica , Bloqueadores dos Canais de Cálcio/química , Feminino , Humanos , Masculino , Nimodipina/química , ComprimidosRESUMO
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.
Assuntos
Nível de Saúde , Hipertensão/epidemiologia , Saúde Pública/normas , Fatores Etários , Causas de Morte , Humanos , Hipertensão/complicações , Hipertensão/terapia , América Latina/epidemiologia , Programas Nacionais de Saúde/normas , Programas Nacionais de Saúde/tendências , Prevalência , Fatores de Risco , Acidente Vascular Cerebral/epidemiologia , Acidente Vascular Cerebral/etiologia , Acidente Vascular Cerebral/prevenção & controle , Taxa de SobrevidaRESUMO
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.
Assuntos
Antagonistas de Receptores de Angiotensina , Anti-Hipertensivos/uso terapêutico , Hipertensão/tratamento farmacológico , Anti-Hipertensivos/farmacocinética , Pressão Sanguínea/efeitos dos fármacos , Humanos , Hipertensão/complicações , Hipertensão/metabolismo , Hipertrofia Ventricular Esquerda/etiologia , Hipertrofia Ventricular Esquerda/metabolismo , Hipertrofia Ventricular Esquerda/prevenção & controle , Losartan/farmacocinética , Losartan/uso terapêutico , Receptor Tipo 1 de Angiotensina , Receptor Tipo 2 de Angiotensina , Receptores de Angiotensina/metabolismo , Resultado do TratamentoRESUMO
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.
Assuntos
Plaquetas/fisiologia , Canais de Cálcio/uso terapêutico , Di-Hidropiridinas/uso terapêutico , Hipertensão/sangue , Nifedipino/uso terapêutico , Agregação Plaquetária/efeitos dos fármacos , Ácido Araquidônico/metabolismo , Biomarcadores/sangue , Plaquetas/efeitos dos fármacos , Pressão Sanguínea/efeitos dos fármacos , Feminino , Frequência Cardíaca/efeitos dos fármacos , Humanos , Hipertensão/tratamento farmacológico , Masculino , Malondialdeído/metabolismo , Pessoa de Meia-Idade , Postura/fisiologia , Método Simples-CegoRESUMO
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.
Assuntos
Anlodipino/uso terapêutico , Inibidores da Enzima Conversora de Angiotensina/uso terapêutico , Bloqueadores dos Canais de Cálcio/uso terapêutico , Enalapril/uso terapêutico , Inibidores da Agregação Plaquetária/uso terapêutico , Agregação Plaquetária/efeitos dos fármacos , Anlodipino/farmacologia , Inibidores da Enzima Conversora de Angiotensina/farmacologia , Bloqueadores dos Canais de Cálcio/farmacologia , Método Duplo-Cego , Enalapril/farmacologia , Feminino , Humanos , Hipertensão/tratamento farmacológico , Masculino , Malondialdeído/metabolismo , Pessoa de Meia-Idade , Inibidores da Agregação Plaquetária/farmacologia , Testes de Função PlaquetáriaRESUMO
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.
Assuntos
Tecido Adiposo , Antropometria/métodos , Composição Corporal , Adulto , Estatura , Índice de Massa Corporal , Peso Corporal , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , VenezuelaRESUMO
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.
Assuntos
Antropometria/métodos , Estatura , Peso Corporal , Estado Nutricional , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Padrões de Referência , Fatores SexuaisRESUMO
This review summarizes the prevalence of hypertension and the state of cardiovascular health in Venezuela and surrounding nations. First, the review discusses the fact that cardiovascular disease (CVD) is the main cause of death in Venezuela, Colombia, Brazil, and Trinidad and Tobago, accounting for 20% to 35% of all deaths. These data are similar to data from the developed world. Second, prevalence of hypertension in this region varies from 8% to 40% in the adult population, and, on average, 22% of the adult population of this region has an elevated blood pressure. However, prevalence rates vary considerably from country to country and within regions of the same country. Although mortality from hypertension as the main cause of death accounts for 1% to 4% of all deaths, mortality from stroke, mainly caused by hypertension, accounts for 10% of all deaths, indicating a failure in the treatment of hypertension. In most Latin American countries, the degree of awareness, treatment and control of hypertension is low, necessitating the establishment of programs to prevent, detect and effectively treat hypertension and decrease CVD risk factors.
Assuntos
Doenças Cardiovasculares/epidemiologia , Hipertensão/epidemiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Brasil/epidemiologia , Doenças Cardiovasculares/mortalidade , Transtornos Cerebrovasculares/epidemiologia , Transtornos Cerebrovasculares/mortalidade , Criança , Pré-Escolar , Colômbia/epidemiologia , Doença das Coronárias/epidemiologia , Doença das Coronárias/mortalidade , Estudos Transversais , Etnicidade , Feminino , Humanos , Hipertensão/mortalidade , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Peru/epidemiologia , Trinidad e Tobago/epidemiologia , Venezuela/epidemiologiaRESUMO
Hypertension is a major risk factor for stroke/myocardial infarction as expression of the atherogenic process. Platelets play a fundamental role in all these disease processes. In physiological conditions there is an equilibrium between pro aggregating and anti aggregating factors. In pathological situations this equilibrium is broken and pro aggregating factors are predominant . Patients with hypertension have an state of hyper-aggregation and dysequilibrium in the production of eicosanoids. Some antihypertensive drugs tend to not only reduce blood pressure to control levels but to reduce platelet aggregation and re-establish the broken equilibrium in eicosanoid production.
Assuntos
Hipertensão/sangue , Agregação Plaquetária , Adulto , Idoso , Anti-Hipertensivos/farmacologia , Anti-Hipertensivos/uso terapêutico , Apirase/metabolismo , Transtornos Cerebrovasculares/epidemiologia , Transtornos Cerebrovasculares/etiologia , Eicosanoides/metabolismo , Endotélio Vascular/embriologia , Feminino , Humanos , Hipertensão/tratamento farmacológico , Hipertensão/epidemiologia , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio/epidemiologia , Infarto do Miocárdio/etiologia , Óxido Nítrico/metabolismo , Agregação Plaquetária/efeitos dos fármacos , Inibidores da Agregação Plaquetária/farmacologia , Inibidores da Agregação Plaquetária/uso terapêutico , Fatores de Risco , Vasodilatação/fisiologia , Venezuela/epidemiologiaRESUMO
Antihypertensive effect, platelet aggregation, and plasma lipid profile were studied in a group of 14 hypertensive patients with diastolic blood pressure between 96 and 116 mm Hg during placebo and terazosin phases. Terazosin, an alpha 1-adrenergic blocking agent, was given initially at the dosage of 1 mg daily. Then it was continued at a dosage of 2 mg daily and 5 mg daily respectively, each dosage for 4 weeks. Blood pressure was taken every 2 weeks. Ex vivo platelet aggregation induced by epinephrine, collagen, and adenosine diphosphate (ADP) were carried out twice during the first placebo phase, once at the end of each terazosin dosage, and once in the second placebo phase. Total cholesterol, HDL cholesterol, and triglycerides were measured at the end of first placebo and terazosin phases. Blood from eight patients was taken during the second placebo phase to carry out in vitro response of platelet aggregation induced by ADP, collagen, and epinephrine before and after incubation with terazosin (1, 2 and 5 micrograms/L or doxazosin (100, 200, and 500 micrograms/L for 5 min. Terazosin induced a statistically significant decrease in 14.2/8.0 mm Hg, 26.1/13.4 mm Hg, and 33.9/16.5 mm Hg in the supine position for 1, 2, and 5 mg/daily, respectively. No changes in heart rate were observed. Terazosin inhibited significant ex vivo platelet aggregation induced by epinephrine, collagen, and ADP in a range from 20% to 45% for different concentrations of inducers. Reductions in platelet aggregation seemed not to be dose dependent, as reductions were statistically equivalent for dosages of 1, 2, and 5 mg daily. Terazosin significantly reduced the level of total cholesterol (8.71%) and triglycerides (14.31%), and increased (although not significantly) levels of HDL cholesterol (3.91%). In vitro platelet aggregation was inhibited by doxazosin to a significant extent but not by terazosin.
Assuntos
Antagonistas Adrenérgicos alfa/farmacologia , Antagonistas Adrenérgicos alfa/uso terapêutico , Anti-Hipertensivos/farmacologia , Anti-Hipertensivos/uso terapêutico , Hipertensão/sangue , Hipertensão/tratamento farmacológico , Inibidores da Agregação Plaquetária/farmacologia , Agregação Plaquetária/efeitos dos fármacos , Prazosina/análogos & derivados , Antagonistas de Receptores Adrenérgicos alfa 1 , Adulto , Idoso , Artérias/fisiopatologia , Pressão Sanguínea/efeitos dos fármacos , Colesterol/sangue , Doxazossina/farmacologia , Doxazossina/uso terapêutico , Feminino , Frequência Cardíaca/efeitos dos fármacos , Humanos , Técnicas In Vitro , Lipídeos/sangue , Masculino , Pessoa de Meia-Idade , Inibidores da Agregação Plaquetária/uso terapêutico , Prazosina/farmacologia , Prazosina/uso terapêutico , Triglicerídeos/sangueRESUMO
OBJECTIVE: To compare the antihypertensive actions of amlodipine and enalapril in a double-blind, randomized, parallel-group study during treatment and when missing a dose. METHOD: After a single-blind run-in 4-week placebo period, patients were randomly allocated to receive enalapril (15 patients) or amlodipine (15 patients). Patients received active treatment for 4 weeks (20 mg enalapril or 5 mg amlodipine). For those with sitting diastolic office pressure not below 90 mmHg the dosage was doubled and continued up to week 12. Ambulatory blood pressure monitoring was performed at the end of the placebo run-in period for 24 h and at the end of week 12 for 48 h; in this case, patients took the active tablet at 0700 h of the first day and a placebo tablet on the next day to stimulate a missing dose in a single-blind manner. RESULTS: Of the patients, 60% had office blood pressure controlled by enalapril therapy and 80% had amlodipine therapy. The average dosage was 30.7 mg a day for enalapril and 7.3 mg a day for amlodipine. Reductions in blood pressures were higher for the amlodipine group. Ambulatory blood pressure measurement shows a reduction in systolic and in diastolic blood pressure during the 24 h when patients from both groups were receiving their medication with respect to placebo values. During the second day of ambulatory blood pressure recording, when the patient had taken a placebo tablet instead of an active one, the antihypertensive effect was progressively lost with enalapril, but not with amlodipine. CONCLUSION: Enalapril and amlodipine reduced ambulatory systolic and diastolic blood pressure during treatment; however, when patients missed an enalapril dose, control of blood pressure was progressively lost, whereas patients receiving amlodipine maintained their blood pressure under control up to 48 h after the last dose.
RESUMO
El cumplimiento en el tratamiento antihipertensivo es muy importante para proteger al paciente de las complicaciones cardíacas y cerebrovasculares de la hipertensión. Con el régimen de dos veces al día, el 50 por ciento toman la medicación prescripta el 90 por ciento de los días de observación, comparado con el 70 por ciento cuando los pacientes cumplen la medicación una vez al día. la acción antihipertensiva de la amlodipina y el enalapril ha sido publicada recientemente por nuestro grupo de investigación, en un estudio controlado, paralelo, doble ciego y al azar. Después de cuatro semanas de recibir placebo en forma ciego-simple, los pacientes fueron asignados a recibir 20 mg de enalapril (15 pacientes) o 5 mg de amlodipina (15 pacientes) una vez al día. En la cuarta semana de medicación activa la dosis fue duplicada, en caso que la presión arterial diastólica en posición sentada fuera superior a 90 mmHg. Un monitoreo ambulatorio de presión arterial fue realizado al final de la etapa placebo por un período de 24 horas y al final de la semana 12 de tratamiento activo por un período de 48 horas. Las reducciones en la presión arterial fueron mayores en el grupo amlodipina
Assuntos
Humanos , Anlodipino/administração & dosagem , Anlodipino/farmacologia , Anlodipino/uso terapêutico , Anti-Hipertensivos/administração & dosagem , Anti-Hipertensivos/uso terapêutico , Enalapril/administração & dosagem , Enalapril/farmacologia , Enalapril/uso terapêutico , Hipertensão/complicações , Hipertensão/tratamento farmacológico , Hipertensão/terapia , Monitorização Ambulatorial da Pressão Arterial , VenezuelaRESUMO
El cumplimiento en el tratamiento antihipertensivo es muy importante para proteger al paciente de las complicaciones cardíacas y cerebrovasculares de la hipertensión. Con el régimen de dos veces al día, el 50 por ciento toman la medicación prescripta el 90 por ciento de los días de observación, comparado con el 70 por ciento cuando los pacientes cumplen la medicación una vez al día. la acción antihipertensiva de la amlodipina y el enalapril ha sido publicada recientemente por nuestro grupo de investigación, en un estudio controlado, paralelo, doble ciego y al azar. Después de cuatro semanas de recibir placebo en forma ciego-simple, los pacientes fueron asignados a recibir 20 mg de enalapril (15 pacientes) o 5 mg de amlodipina (15 pacientes) una vez al día. En la cuarta semana de medicación activa la dosis fue duplicada, en caso que la presión arterial diastólica en posición sentada fuera superior a 90 mmHg. Un monitoreo ambulatorio de presión arterial fue realizado al final de la etapa placebo por un período de 24 horas y al final de la semana 12 de tratamiento activo por un período de 48 horas. Las reducciones en la presión arterial fueron mayores en el grupo amlodipina (AU)
Assuntos
Humanos , Hipertensão/tratamento farmacológico , Hipertensão/terapia , Hipertensão/complicações , Anlodipino/administração & dosagem , Anlodipino/farmacologia , Anlodipino/uso terapêutico , Enalapril/administração & dosagem , Enalapril/farmacologia , Enalapril/uso terapêutico , Anti-Hipertensivos/administração & dosagem , Anti-Hipertensivos/uso terapêutico , Monitorização Ambulatorial da Pressão Arterial , VenezuelaRESUMO
An in vitro assay was used to investigate the effects of doxazosin on the platelet aggregation induced by epinephrine, collagen, and adenosine diphosphate. Platelet-rich plasma from normotensive subjects and patients with hypertension was compared. Doxazosin produced a concentration-dependent inhibition of platelet aggregation in both groups, but significantly lower concentrations were required to inhibit platelet aggregation in plasma taken from patients with hypertension. The concentrations of doxazosin that inhibited platelet aggregation in vitro were similar to those that are used clinically to control blood pressure in patients with hypertension.