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2.
Scanning ; 2017: 4058636, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29109810

RESUMO

Low-pressure cold spraying is a newly developed technology with high application potential. The aim of this study was to investigate potential application of this technique for producing a new type of transparent conductive oxide films target. Cold spraying technique allows the manufacture of target directly on the backing plate; therefore the proposed sputtering target has a form of Sn+In2O3 coating sprayed onto copper substrate. The microstructure and properties of the feedstock powder prepared using three various methods as well as the deposited ones by low-pressure cold spraying coatings were evaluated, compared, and analysed. Produced cermet Sn+In2O3 targets were employed in first magnetron sputtering process to deposit preliminary, thin, transparent conducting oxide films onto the glass substrates. The resistivity of obtained preliminary films was measured and allows believing that fabrication of TCO (transparent conducting oxide) films using targets produced by cold spraying is possible in the future, after optimization of the deposition conditions.

3.
Kidney Int ; 70(3): 578-84, 2006 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-16788693

RESUMO

Factors related to the development of microalbuminuria in hypertension are not well known. We did a prospective study to investigate whether glomerular hyperfiltration precedes the development of microalbuminuria in hypertension. We assessed 502 never-treated subjects screened for stage 1 hypertension without microalbuminuria at baseline and followed up for 7.8 years. Creatinine clearance was measured at entry. Urinary albumin and ambulatory blood pressure were measured at entry and during the follow-up until subjects developed sustained hypertension needing antihypertensive treatment. Subjects with hyperfiltration (creatinine clearance >150 ml/min/1.73 m2, top quintile of the distribution) were younger and heavier than the rest of the group and had a greater follow-up increase in urinary albumin than subjects with normal filtration (P<0.001). In multivariable linear regression, creatinine clearance adjusted for confounders was a strong independent predictor of final urinary albumin (P<0.001). In multivariable Cox regression, patients with hyperfiltration had an adjusted hazard ratio for the development of microalbuminuria based on at least one positive measurement of 4.0 (95% confidence interval (CI), 2.1-7.4, P<0.001) and an adjusted hazard ratio for the development of microalbuminuria based on two consecutive positive measurements of 4.4 (95% CI, 2.1-9.2, P<0.001), as compared with patients with normal filtration. Age, female gender, and 24 h systolic blood pressure were other significant predictors of microalbuminuria. In conclusion, stage 1 hypertensive subjects with glomerular hyperfiltration are at increased risk of developing microalbuminuria. Early intervention with medical therapy may be beneficial in these subjects even if their blood pressure falls below normal limits during follow-up.


Assuntos
Albuminúria/diagnóstico , Albuminúria/epidemiologia , Taxa de Filtração Glomerular , Hipertensão Renal/diagnóstico , Hipertensão Renal/epidemiologia , Adulto , Albuminúria/fisiopatologia , Feminino , Seguimentos , Humanos , Hipertensão Renal/fisiopatologia , Incidência , Modelos Lineares , Masculino , Análise Multivariada , Valor Preditivo dos Testes , Modelos de Riscos Proporcionais , Fatores de Risco , Distribuição por Sexo
4.
Circulation ; 104(8): 903-7, 2001 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-11514377

RESUMO

BACKGROUND: Most subjects with blood/injury phobia experience syncope or presyncope as part of the phobic response. We tested the hypothesis that these subjects have a constitutional autonomic dysregulation that predisposes them to vasovagal syncope during head-up tilt. METHODS AND RESULTS: We studied 11 subjects (9 females, 2 males) who had a history of syncope or presyncope only in response to a blood or injury stimulus and 11 healthy matched controls (10 females, 1 male) without a history of syncope. Blood pressure (BP) and heart rate (HR) were measured during a 15-minute baseline period with subjects in the supine position and then during 45 minutes of head-up tilt to 70 degrees. Measurements at rest did not differ between the blood phobic and control subjects. During tilt, 9 (82%) of the 11 blood phobic subjects experienced presyncope or syncope, leading to termination of the study after 22+/-17 minutes of tilt. Only 1 (9%) of the 11 control subjects experienced presyncope (chi(2)=11.7, P=0.001). Hemodynamic responses to tilt were consistent with a vasovagal mechanism in the blood phobic subjects, with simultaneous decreases in BP and HR during tilt. During tilt, systolic BP fell by 21+/-15 mm Hg (P=0.001), and HR fell by 22+/-25 bpm (P=0.01). By contrast, BP and HR were very stable in the control group. CONCLUSIONS: Subjects with syncope related to blood/injury phobia have an underlying autonomic dysregulation predisposing them to neurally mediated syncope, even in the absence of any blood or injury stimulus. Fainting related to these stimuli may in large part be due to dysfunction in neural circulatory control, which may secondarily lead to the phobia because of repeated syncopal events.


Assuntos
Transtornos Fóbicos/diagnóstico , Transtornos Fóbicos/fisiopatologia , Postura , Síncope Vasovagal/diagnóstico , Síncope Vasovagal/fisiopatologia , Adulto , Sistema Nervoso Autônomo/fisiopatologia , Pressão Sanguínea , Índice de Massa Corporal , Feminino , Frequência Cardíaca , Humanos , Masculino , Transtornos Fóbicos/complicações , Síncope Vasovagal/etiologia , Teste da Mesa Inclinada
5.
Circulation ; 104(4): 384-6, 2001 Jul 24.
Artigo em Inglês | MEDLINE | ID: mdl-11468197

RESUMO

BACKGROUND: Leptin, the protein product of the ob gene, has been linked to a faster heart rate in animal and human studies. The interaction between leptin and heart rate in the denervated heart is not known. Therefore, we studied the relationship between plasma leptin levels and heart rate in heart transplant recipients. METHODS AND RESULTS: We studied 32 male patients (mean age, 56.5+/-9.3 years; range, 41 to 74 years) after orthotopic heart transplantation. All subjects underwent a physical examination, anthropometric measurements, blood chemistry analysis, and office blood pressure measurements. A blood sample was collected from each subject while fasting. In univariate analysis, heart rate was related to leptin levels (r=0.47, P=0.007) but heart rate was not related to systolic or diastolic blood pressure, mean arterial pressure, body mass index, or catecholamines. Leptin levels were only strongly associated with heart rate and body mass index (r=0.73, P<0.0001). In multivariate analysis, heart rate was independently and positively associated with leptin levels (F=2.61, P=0.017). We also observed a strong, independent association between leptin levels and body mass index (F=5.8, P<0.00001). CONCLUSIONS: We show an independent association between leptin levels and heart rate in heart transplant recipients. We speculate that this may be due, in part, to a direct effect of leptin on heart rate, conceivably mediated through cardiac leptin receptors.


Assuntos
Frequência Cardíaca/fisiologia , Transplante de Coração , Leptina/sangue , Adulto , Idoso , Pressão Sanguínea/fisiologia , Epinefrina/sangue , Humanos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Norepinefrina/sangue , Fatores de Tempo
6.
J Hypertens ; 19(6): 1089-94, 2001 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-11403358

RESUMO

OBJECTIVE: Administration of leptin to animals increases sympathetic nerve activity and heart rate. We therefore tested the hypothesis that plasma leptin is linked independently to muscle sympathetic nerve activity (MSNA) and heart rate in healthy humans. METHODS: We measured plasma leptin, plasma insulin, body mass index (BMI), percent body fat, waist: hip ratio, MSNA, heart rate and blood pressure in 88 healthy individuals (50 men and 38 women). RESULTS: In men, plasma leptin concentration correlated significantly with BMI (r = 0.75, P < 0.001), percent body fat (r = 0.70, P< 0.001), waist: hip ratio (r = 0.69, P < 0.001), insulin (r = 0.37, P = 0.009), and age (r = 0.38, P = 0.006). Only BMI and waist: hip ratio were linked independently to plasma leptin concentration (r = 0.78, P < 0.001). Plasma leptin concentrations also correlated with heart rate (r = 0.39, P = 0.006) and mean arterial pressure (MAP; r = 0.38, P = 0.007), but not with MSNA (r = 0.17, P = 0.24). After adjustment for BMI and waist: hip ratio, plasma leptin concentration correlated significantly only with heart rate (r = 0.29, P = 0.04), and not with MAP (r = 0.21, P = 0.14). Individuals were divided into high-leptin and low-leptin subgroups on the basis of plasma leptin concentrations adjusted for BMI and waist: hip ratio. Those with high leptin concentrations had significantly faster heart rates than those with low leptin. MAP and MSNA were similar in both subgroups. No relationship between leptin and either heart rate or MSNA was evident in women. CONCLUSIONS: In normal men, heart rate, but not MSNA, is linked to plasma leptin concentration. This sex-specific relationship between heart rate and plasma leptin is independent of plasma insulin, BMI, waist:hip ratio and percentage body fat.


Assuntos
Frequência Cardíaca/fisiologia , Leptina/fisiologia , Sistema Nervoso Simpático/fisiologia , Adulto , Animais , Pressão Sanguínea/fisiologia , Constituição Corporal , Índice de Massa Corporal , Feminino , Humanos , Insulina/sangue , Leptina/sangue , Masculino , Pessoa de Meia-Idade , Músculos/inervação , Caracteres Sexuais
7.
Am J Hypertens ; 14(12): 1191-5, 2001 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11775125

RESUMO

BACKGROUND: A nucleotide substitution (C-->T) at position 825 of the gene GNB3 encoding the beta3 subunit of heterotrimeric G proteins is associated with alternative splicing and enhanced signal transduction. There is accumulating evidence from different populations that the 825T allele is associated with increased prevalence of hypertension, obesity, and left ventricular hypertrophy. However, it is unclear to what extent the 825T allele has a direct influence on left ventricular structure, independently of the effects of pressure and body mass index. Therefore we explored whether the GNB3 825T allele is associated with increased left ventricular mass index in a selected and homogeneous group of young, never treated, mild hypertensives. PROCEDURES: Young subjects (n = 207, aged 18 to 45 years) were genotyped at the GNB3 825 locus. In each patient, 24-h ambulatory blood pressure (BP) measurement and two-dimensional guided M-mode echocardiography combined with Doppler sonography were performed. RESULTS: The genotype distribution among patients was in Hardy-Weinberg equilibrium. Patients carrying the 825T allele had an increased left ventricular mass index (95.1 +/- 1.5 v 89.7 +/- 1.5 g/m2; P = .01) in comparison to those with CC genotype. The association between left ventricular mass index and 825T allele was independent of gender, age, BP, heart rate, alcohol intake, and physical activity. CONCLUSIONS: In young patients with mild hypertension without heart disease the 825T allele is associated with an increased left ventricular mass index. These hypothesis-generating data suggest that GNB3 825T allele may be considered as one genetic marker predisposing to an increase in left ventricular mass in hypertensives, and justifies larger studies.


Assuntos
Proteínas Heterotriméricas de Ligação ao GTP/genética , Hipertensão/genética , Hipertrofia Ventricular Esquerda/genética , Transdução de Sinais/genética , Adulto , Fatores Etários , Substituição de Aminoácidos , Ecocardiografia , Feminino , Genótipo , Heterozigoto , Homozigoto , Humanos , Hipertrofia Ventricular Esquerda/diagnóstico por imagem , Hipertrofia Ventricular Esquerda/patologia , Masculino
8.
Circulation ; 102(21): 2607-10, 2000 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-11085964

RESUMO

BACKGROUND: Patients with obstructive sleep apnea (OSA) experience repetitive episodic hypoxemia with consequent sympathetic activation and marked blood pressure surges, each of which may impair endothelial function. We tested the hypothesis that patients with OSA have impaired endothelium-dependent vasodilation, even in the absence of overt cardiovascular disease. METHODS AND RESULTS: We studied 8 patients with OSA (age 44+/-4 years) and 9 obese control subjects (age 48+/-3 years). Patients with OSA were newly diagnosed, never treated for OSA, on no medications, and free of any other known diseases. All obese control subjects underwent complete overnight polysomnographic studies to exclude occult OSA. Resistance-vessel function was tested by use of forearm blood flow responses to intra-arterial infusions of acetylcholine (a vasodilator that stimulates endothelial release of nitric oxide), sodium nitroprusside (an exogenous nitric oxide donor), and verapamil (a calcium channel blocker). Conduit-vessel function was also evaluated by ultrasonography. Brachial artery diameter was measured under baseline conditions, during reactive hyperemia (with flow increase causing endothelium-dependent dilatation), and after sublingual administration of nitroglycerin (an endothelium-independent vasodilator). Patients with OSA had a blunted vasodilation in response to acetylcholine (P:<0.007), but responses to sodium nitroprusside and verapamil were not significantly different from those of control subjects. No significant difference in conduit-vessel dilation was evident between OSA patients and obese control subjects. CONCLUSIONS: Patients with OSA have an impairment of resistance-vessel endothelium-dependent vasodilation. This may be implicated in the pathogenesis of hypertension and heart failure in this condition.


Assuntos
Endotélio Vascular/fisiopatologia , Obesidade/fisiopatologia , Apneia Obstrutiva do Sono/fisiopatologia , Resistência Vascular , Vasodilatação , Acetilcolina/administração & dosagem , Adulto , Velocidade do Fluxo Sanguíneo/efeitos dos fármacos , Artéria Braquial/diagnóstico por imagem , Artéria Braquial/efeitos dos fármacos , Relação Dose-Resposta a Droga , Eletrocardiografia , Antebraço/irrigação sanguínea , Antebraço/diagnóstico por imagem , Frequência Cardíaca/efeitos dos fármacos , Humanos , Hiperemia/fisiopatologia , Infusões Intra-Arteriais , Masculino , Pessoa de Meia-Idade , Obesidade/complicações , Polissonografia , Apneia Obstrutiva do Sono/complicações , Ultrassonografia , Resistência Vascular/efeitos dos fármacos , Vasodilatação/efeitos dos fármacos , Vasodilatadores/administração & dosagem
9.
Am J Hypertens ; 13(1 Pt 1): 92-8, 2000 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-10678277

RESUMO

This study was undertaken to assess the reproducibility of office versus ambulatory heart rates in 839 hypertensive subjects participating in the Hypertension and Ambulatory Recording Venetia Study (HARVEST). A 24-hour heart rate was recorded twice; this procedure was repeated three months later. Reproducibility was better for ambulatory than for office measurement, and was greater for 24-hour than for daytime heart rate, and lowest for night-time heart rate. Reproducibility of office heart rate was impaired above 85 bpm, and was poorer in subjects with more severe office hypertension. A small but significant decrease in average daytime (-1 bpm, P < 0.0001) and virtually no change in night-time heart rate (-0.3 bpm, NS) were observed at repeat recording. Heart rate reproducibility indices were related to the extent of the heart rate and blood pressure white-coat effect, but did not vary according to age, gender, body mass index, day-night blood pressure difference, or alcohol or tobacco use. Results indicate that heart rate recorded over the 24 hours has a better reproducibility than office heart rate, and could thus be a better prognostic indicator than traditional measurement of resting heart rate in the hospital setting.


Assuntos
Frequência Cardíaca/fisiologia , Hipertensão/diagnóstico , Monitorização Ambulatorial , Adulto , Pressão Sanguínea/fisiologia , Ritmo Circadiano , Feminino , Humanos , Hipertensão/psicologia , Masculino , Reprodutibilidade dos Testes , Caracteres Sexuais
10.
Circulation ; 102(25): 3068-73, 2000 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-11120696

RESUMO

BACKGROUND: Sildenafil citrate is an effective and widely prescribed therapy for erectile dysfunction. Little is known about the effects of sildenafil on neural control of the circulation or about the effects of sildenafil on neurocirculatory stress responses. METHODS AND RESULTS: We studied 14 normal volunteers (age 32+/-7 years) who were randomized in a double-blind crossover fashion to receive a single oral dose of sildenafil 100 mg or placebo on 2 separate study days. Blood pressure, heart rate, forearm vascular resistance, muscle sympathetic nerve activity, and plasma catecholamines were measured at baseline and at 30 and 60 minutes after sildenafil and after placebo administration. The effects of sildenafil and placebo on neural and circulatory responses to stressful stimuli (sustained handgrip, maximal forearm ischemia, mental stress, and the cold pressor test) were also evaluated. Blood pressure, heart rate, and forearm vascular resistance after sildenafil and placebo were similar. However, muscle sympathetic nerve activity increased strikingly after sildenafil (by 141+/-26%, mean+/-SEM) compared with placebo (3+/-8%) (P=0.006); plasma norepinephrine levels also increased by 31+/-5% after sildenafil administration (P=0.004). Sympathetic nerve traffic during mental, physical, and cold stresses was 2- to 8-fold higher after sildenafil than with placebo (P<0.05). CONCLUSIONS: Sildenafil causes a marked increase in sympathetic activation, evident both at rest and during stressful stimuli. Sympathetic activation by sildenafil may have implications for understanding cardiovascular events associated with sildenafil use.


Assuntos
Hemodinâmica/efeitos dos fármacos , Inibidores de Fosfodiesterase/farmacologia , Diester Fosfórico Hidrolases/metabolismo , Piperazinas/farmacologia , Sistema Nervoso Simpático/efeitos dos fármacos , Vasodilatadores/farmacologia , 3',5'-GMP Cíclico Fosfodiesterases , Adulto , Pressão Sanguínea/efeitos dos fármacos , Pressão Venosa Central/efeitos dos fármacos , Estudos Cross-Over , Nucleotídeo Cíclico Fosfodiesterase do Tipo 5 , Método Duplo-Cego , Frequência Cardíaca/efeitos dos fármacos , Humanos , Pressão Negativa da Região Corporal Inferior , Masculino , Músculo Esquelético/inervação , Purinas , Descanso , Citrato de Sildenafila , Estresse Fisiológico/fisiopatologia , Sulfonas
11.
J Hypertens ; 17(6): 749-56, 1999 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-10459871

RESUMO

OBJECTIVE: To determine the relationships between lifestyle and cardiovascular risk factors among the Brazilian Amondava, one of the world's most isolated populations. DESIGN: Cross-sectional, population-based study. Four age- and sex-matched samples from Brazil Africa, Italy and Poland, representing different levels of modernization, were compared. Body weight, height, blood pressure, serum cholesterol and glycaemia were measured, and a standard questionnaire administered. Data concerning dietary habits and physical activity were collected. A personal socio-economic score was calculated, on the basis of type of economy, level of formal education, type of occupation, type of habitat, availability of piped water and electricity, main source of income, housing conditions, availability of radio, television or personal computer, knowledge of a second language, and organized health facilities. SETTING: Primary epidemiological screening, at an institution. RESULTS: Among the Amondava blood pressure was always <140/90 mm Hg, it did not increase with age and was not correlated with any other variable; 46.6% of subjects had systolic blood pressure <100 mm Hg. Blood pressure among the Amondava (109.6+/-11.1/69.5+/-6.4 mm Hg) was on average lower (P<0.0001) than in all other samples. Among the Amondava, the concentration of total cholesterol was always <200 mg/dl, i.e. similar to that of Africans whose diet included large amounts of vegetable foodstuffs; 90% had glycaemia (<80 mg/dl), and their mean value was the lowest (55.1+/-14.9 mg/dl) of all the groups. CONCLUSIONS: In addition to a possible genetic predisposition not analysed in this study, a traditional lifestyle (no contact with civilization, diet based on complex carbohydrates and vegetables, high energy expenditure) may protect against the development of hypertension, hypercholesterolaemia, and diabetes.


Assuntos
Doenças Cardiovasculares/epidemiologia , Indígenas Sul-Americanos , Estilo de Vida , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Pressão Sanguínea , Brasil/epidemiologia , Doenças Cardiovasculares/sangue , Doenças Cardiovasculares/etnologia , Criança , Colesterol/sangue , Estudos Transversais , Comportamento Alimentar , Humanos , Indígenas Sul-Americanos/estatística & dados numéricos , Pessoa de Meia-Idade , Polônia/epidemiologia , Vigilância da População , Estudos Retrospectivos , Fatores de Risco , Classe Social , África do Sul/epidemiologia
12.
J Hypertens ; 17(5): 647-55, 1999 May.
Artigo em Inglês | MEDLINE | ID: mdl-10403608

RESUMO

OBJECTIVE: We investigated the determinants of plasma renin activity (PRA) and plasma levels of angiotensin-converting enzyme (pACE), including the effect of the D/I polymorphism of the angiotensin-converting enzyme (ACE) gene, in monozygotic (MZ) and dizygotic (DZ) twins. METHODS: Sixty-nine pairs of twins underwent measurements of blood pressure, pACE and ACE D/I genotyping. In addition, in 30 pairs ambulatory blood pressure (ABP) monitoring was carried out. To ascertain twin's zygosity, some highly discriminating variable number of tandem repeats micro- and mini-satellite systems were analysed by polymerase chain reaction (PCR) followed by polyacrylamide gel electrophoresis and silver staining. The D/I polymorphism was assessed by PCR; pACE was measured in triplicate with a colorimetric assay, and PRA by a commercial kit. In DZ twins, identity by descent of the D/I alleles was examined by PCR amplification of a highly polymorphic simple sequence repeat at the human growth hormone gene. RESULTS: pACE levels were significantly (P < 0.01) higher in DD (9.27 +/- 2.60 IU/l, mean +/-SD) than in II (6.68 +/- 3.0), with DI having intermediate levels (7.93 +/- 2.7). No difference of PRA between different D/I genotypes was found. Twin data analysis showed a statistically significant heritability of pACE, but not of PRA. No differences between MZ and DZ twins in PRA, pACE and the relationship of the D/I genotype with pACE was found. Besides showing that the D/I genotype was the most important predictor of pACE, a multivariate analysis demonstrated that identity by descent of the D/I allele, as assessed by growth hormone (GH) genotyping, also significantly affected pACE. CONCLUSIONS: In this study of normotensive twins, pACE and not PRA showed significant heritability, the former being tightly associated with the D/I ACE gene polymorphism, and/or with a quantitative trait locus in linkage disequilibrium with it.


Assuntos
Peptidil Dipeptidase A/genética , Renina/genética , Gêmeos Dizigóticos/genética , Gêmeos Monozigóticos/genética , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Peptidil Dipeptidase A/sangue , Polimorfismo Genético , Renina/sangue
14.
J Hypertens ; 17(1): 27-31, 1999 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-10100090

RESUMO

OBJECTIVE: To examine the influence of genetic factors on plasma leptin levels. SUBJECTS AND METHODS: We measured plasma leptin levels, body mass index and body fat distribution in healthy young female monozygotic (n = 19) and dizygotic (n = 14) twins. The twin zygosity was verified by determination of short tandem repeat and amplified fragment length polymorphism systems. The genetic analysis included analysis of variance-based and maximum likelihood-based methods. RESULTS: Plasma leptin levels were correlated significantly with body mass index (r = 0.59, P < 0.001), waist circumference (r = 0.54, P < 0.001) and hip circumference (r = 0.63, P < 0.001), but not with age (r = -0.17) or the waist:hip ratio (r = 0.02). The heritability estimates derived from intraclass correlations were significant for body mass index (P = 0.001), waist circumference (P = 0.004), hip circumference (P = 0.01) and plasma leptin levels (P = 0.005), but not for the waist:hip ratio (P = 0.22). In the maximum likelihood-based path analysis, heritability was estimated at 79% for body mass index and at 73% for plasma leptin levels. After adjustment for body mass index, the heritability estimate for leptin levels from the model-fitting approach was 55%. CONCLUSIONS: Genetic factors are major determinants of plasma leptin levels in humans and may account for as much as half of the variance in leptin levels.


Assuntos
Ligação Genética , Proteínas/metabolismo , Gêmeos Dizigóticos/genética , Gêmeos Monozigóticos/genética , Tecido Adiposo/fisiologia , Adolescente , Adulto , Constituição Corporal , Índice de Massa Corporal , Feminino , Humanos , Leptina , Obesidade/sangue , Obesidade/genética , Polimorfismo de Fragmento de Restrição , Valores de Referência
15.
Pol Arch Med Wewn ; 99(3): 203-10, 1998 Mar.
Artigo em Polonês | MEDLINE | ID: mdl-9760806

RESUMO

It has been reported that the allel D of an insertion/deletion (I/D) polymorphism of the angiotensin I converting enzyme (ACE) gene is associated with the conditions of increased cardiovascular risk, including the left ventricular hypertrophy and the dysfunction. We examined the relation between the genotype of ACE gene and the left ventricular function in normotensives and in borderline, mild and moderate hypertensives. We investigated 128 subjects, 47 first-diagnosed untreated hypertensives and 81 normotensives. The M-mode and Doppler echocardiography were used to quantify LV mass and function. The insertion/deletion ACE polymorphism was identified using polymerase chain reaction. Left ventricular indexes of the morphology and function were analyzed. We compared ambulatory blood pressure profiles between all genotypes in both groups. There were no significant differences in indexes of the left ventricular hypertrophy in studied normotensives and borderline to mild hypertensives. Our results indicate that allel I might be associated with selected parameters of diastolic function, while allel D with selected parameters of systolic function, of the left ventricle. Results of this study suggest also probable relation between allel D and variability of the diastolic arterial pressure in both investigated groups.


Assuntos
Hipertensão/fisiopatologia , Peptidil Dipeptidase A/genética , Função Ventricular Esquerda , Adulto , Ecocardiografia , Ecocardiografia Doppler , Feminino , Genótipo , Ventrículos do Coração/diagnóstico por imagem , Humanos , Hipertensão/diagnóstico por imagem , Masculino , Polimorfismo Genético
16.
Clin Exp Hypertens ; 20(3): 283-94, 1998 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-9605383

RESUMO

The aim of the present study was to evaluate the relationship between the angiotensin I converting enzyme (ACE) gene polymorphism and ambulatory blood pressure in young normotensive males with (n=45) and without (n=100) family history of hypertension. Twenty-four hour and daytime systolic blood pressure was significantly higher in subjects with a parental history of hypertension. Ambulatory blood pressure values did not differ significantly across ACE genotypes in subjects with negative family history of hypertension. In subjects with a parental history of hypertension, there was a significant positive association between the D allele of the ACE gene polymorphism and 24-h, daytime and nighttime systolic blood pressure. For twenty-four hour systolic blood pressure there was an average 9 mmHg difference between subjects with DD and II genotypes. The results indicate that in normotensive subjects with a genetic predisposition to hypertension, ambulatory systolic blood pressure is related to the D allele of the ACE gene.


Assuntos
Alelos , Monitorização Ambulatorial da Pressão Arterial , Pressão Sanguínea/fisiologia , Deleção de Genes , Hipertensão/genética , Peptidil Dipeptidase A/genética , Adulto , Genótipo , Frequência Cardíaca/fisiologia , Humanos , Hipertensão/fisiopatologia , Masculino , Polimorfismo Genético/genética , Valores de Referência
17.
Blood Press Monit ; 3(4): 255-260, 1998 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-10212363

RESUMO

OBJECTIVE: To determine the accuracy of the TM-2430 blood pressure monitor, recently developed by the A&D company. DESIGN: Evaluation was performed using the 1990 and 1993 British Hypertension Society (BHS) protocols. Monitor's performance was assessed in relation to subjects' age, sex, level of blood pressure, and degree of adiposity. METHODS: Three TM-2430 recorders were assessed according to the various phases of the protocols. Simultaneous, same-arm readings were taken for the main validation test. Outcome was classified according to the criteria from the 1990 BHS recommendations, which are based on the cumulative percentage of readings differing from the mercury sphygmomanometer standard by 5, 10, and 15 mmHg or less, and using the criteria of the Association for the Advancement of Medical Instrumentation protocol, which considers a device accurate when the mean device-observer difference is within 5 mmHg and the related SD < 8 mmHg. RESULTS: During in-use assessment 2.3% of total measurements (N = 3744) were rejected automatically by the machine and another 5.5% werre discarded after visual inspection. The main validation test was performed with 98 subjects for a total of 595 blood pressure measurements. On the basis of the percentages of measurements differing from the mercury sphygmomanometer standard by

18.
Am J Hypertens ; 10(6): 692-5, 1997 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-9194518

RESUMO

The aim of the study was to evaluate the potential association between ambulatory blood pressure and the molecular variants T174M and M235T of the angiotensinogen gene in a random sample of young normotensive men (n = 145). The two point mutations were detected using restriction digests of a mispairing polymerase chain reaction product. Twenty-four-hour ambulatory blood pressure monitoring was performed with a SpaceLabs 90207 device. Ambulatory blood pressure levels did not vary according to T174M and M235T genotypes. When the subjects were grouped according to their blood pressure level (as indicated by tertiles of their 24-h ambulatory blood pressure), no significant differences in allele frequencies between the three groups were found. Our results indicate that the T174M and M235T molecular variants of the angiotensinogen gene have no major influence on ambulatory blood pressure in young normotensive subjects.


Assuntos
Angiotensinogênio/genética , Pressão Sanguínea/genética , Adulto , Monitorização Ambulatorial da Pressão Arterial , Humanos , Masculino , Polimorfismo Genético
19.
Am J Hypertens ; 10(4 Pt 1): 419-27, 1997 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-9128208

RESUMO

The effect of different editing methods on the reproducibility of ambulatory blood pressure and on its correlation with microalbuminuria was studied in a population of 584 stage I hypertensives participating in the Hypertension and Ambulatory Recording Venetia Study (HARVEST) Group. For systolic blood pressure (SBP), a modified version of the Casadei method showed the best reproducibility indices, followed by the original Casadei and the Kennedy methods. The Staessen, SpaceLabs, and A&D methods showed poorer indices, irrespective of whether calculations were made in recordings with more or less than 10% artifactual readings. For diastolic blood pressure (DBP), reproducibility indices did not substantially vary with the various editing procedures except for the Kennedy method, which showed a slightly better performance. Blood pressure variability (standard deviation) showed a better reproducibility with the original and modified versions of the Casadei and the Kennedy procedures than with the other methods, especially in the subjects with percentage of measurement errors greater than 10%. The correlation coefficients between 24-h SBP and albumin excretion rate ranged from 0.128 for the raw data to 0.154 for the data edited according to the Casadei procedures. For DBP, the correlation coefficients were similar except for DBP edited with the Kennedy method, which did not correlate with albumin excretion rate to a statistically significant level. These data suggest that, to make the results of different laboratories comparable, common ambulatory blood pressure editing criteria should be used. The modified version of the Casadei procedure, which is automatic and can be applied to recordings obtained from any device, should be regarded as the method of choice.


Assuntos
Albuminúria/fisiopatologia , Monitorização Ambulatorial da Pressão Arterial/normas , Pressão Sanguínea , Hipertensão/fisiopatologia , Adolescente , Adulto , Humanos , Pessoa de Meia-Idade
20.
J Hum Hypertens ; 11(2): 119-23, 1997 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-9140799

RESUMO

We investigated exercise induced urinary albumin excretion rate (UAE)(ex-UAE) in patients with borderline hypertension (BH) compared to normotensives with positive-PFH and negative-NFH family history of hypertension. The study population consisted of 20 young, non-obese males with BH defined according to WHO criteria and confirmed by 24 h ambulatory blood pressure (ABP) and 40 healthy matched normotensives (PFH = 20 and NFH = 20). Twenty-four hour UAE was assessed by day and night time urine collection. BH and normotensive subjects performed a 20 min ergometric graded exercise test. The relationship between 24 h UAE, 24 h ABP and 2-D-echocardiographic left ventricular mass index (LVMI) were examined. The three groups did not differ in 24 h UAE. Exercise induced a significant increase in UAE only in BH. Exercise induced UAE was greater in BH compared to normotensives: BH = 54.3(21-125), PFH = 37.6(13-62), NFH = 9.7(0-35)micrograms/min, data expressed as median (I quartile-III quartile). Pooled data from all three groups showed a positive correlation between ex-UAE and systolic BP (SBP) during night time (by multiple regression analysis). In conclusion, BH without other known cardiovascular risk factors, moderate dynamic exercise induced an excessive increase in UAE.


Assuntos
Albuminúria/fisiopatologia , Hipertensão/fisiopatologia , Albuminúria/genética , Pressão Sanguínea , Exercício Físico , Teste de Esforço , Humanos , Hipertensão/genética , Hipertensão/urina , Fatores de Risco
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