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1.
Rev. bras. pesqui. méd. biol ; Braz. j. med. biol. res;43(7): 681-686, July 2010. ilus, tab
Artigo em Inglês | LILACS | ID: lil-550739

RESUMO

We determined the sympathetic and parasympathetic control of heart rate (HR) and the sensitivity of the cardiopulmonary receptors after selective carotid and aortic denervation. We also investigated the participation of the autonomic nervous system in the Bezold-Jarish reflex after selective removal of aortic and carotid baroreceptors. Male Wistar rats (220-270 g) were divided into three groups: control (CG, N = 8), aortic denervation (AG, N = 5) and carotid denervation (CAG, N = 9). AG animals presented increased arterial pressure (12 percent) and HR (11 percent) compared with CG, while CAG animals presented a reduction in arterial pressure (16 percent) and unchanged HR compared with CG. The sequential blockade of autonomic effects by atropine and propranolol indicated a reduction in vagal function in CAG (a 50 and 62 percent reduction in vagal effect and tonus, respectively) while AG showed an increase of more than 100 percent in sympathetic control of HR. The Bezold-Jarish reflex was evaluated using serotonin, which induced increased bradycardia and hypotension in AG and CAG, suggesting that the sensitivity of the cardiopulmonary reflex is augmented after selective denervation. Atropine administration abolished the bradycardic responses induced by serotonin in all groups; however, the hypotensive response was still increased in AG. Although the responses after atropine were lower than the responses before the drug, indicating a reduction in vagal outflow after selective denervation, our data suggest that both denervation procedures are associated with an increase in sympathetic modulation of the vessels, indicating that the sensitivity of the cardiopulmonary receptors was modulated by baroreceptor fibers.


Assuntos
Animais , Masculino , Ratos , Aorta Torácica/inervação , Seio Carotídeo/inervação , Pressorreceptores/fisiologia , Reflexo/fisiologia , Sistema Nervoso Autônomo/fisiologia , Pressão Sanguínea , Ratos Wistar
2.
Clin Exp Pharmacol Physiol ; 37(3): e114-20, 2010 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19930428

RESUMO

1. Baroreceptors regulate moment-to-moment blood pressure (BP) variations, but their long-term effect on the cardiovascular system remains unclear. Baroreceptor deficit accompanying hypertension contributes to increased BP variability (BPV) and sympathetic activity, whereas exercise training has been associated with an improvement in these baroreflex-mediated changes. The aim of the present study was to evaluate the autonomic, haemodynamic and cardiac morphofunctional effects of long-term sinoaortic baroreceptor denervation (SAD) in trained and sedentary spontaneously hypertensive rats (SHR). 2. Rats were subjected to SAD or sham surgery and were then further divided into sedentary and trained groups. Exercise training was performed on a treadmill (five times per week, 50-70% maximal running speed). All groups were studied after 10 weeks. 3. Sinoaortic baroreceptor denervation in SHR had no effect on basal heart rate (HR) or BP, but did augment BPV, impairing the cardiac function associated with increased cardiac hypertrophy and collagen deposition. Exercise training reduced BP and HR, re-established baroreflex sensitivity and improved both HR variability and BPV. However, SAD in trained SHR blunted all these improvements. Moreover, the systolic and diastolic hypertensive dysfunction, reduced left ventricular chamber diameter and increased cardiac collagen deposition seen in SHR were improved after the training protocol. These benefits were attenuated in trained SAD SHR. 4. In conclusion, the present study has demonstrated that the arterial baroreflex mediates cardiac disturbances associated with hypertension and is crucial for the beneficial cardiovascular morphofunctional and autonomic adaptations induced by chronic exercise in hypertension.


Assuntos
Adaptação Fisiológica/fisiologia , Denervação Autônoma , Barorreflexo/fisiologia , Hipertensão/terapia , Condicionamento Físico Animal , Pressorreceptores/fisiologia , Animais , Frequência Cardíaca/fisiologia , Hipertensão/fisiopatologia , Masculino , Contração Miocárdica , Condicionamento Físico Animal/métodos , Pressorreceptores/cirurgia , Ratos , Ratos Endogâmicos SHR
3.
Rev. bras. pesqui. méd. biol ; Braz. j. med. biol. res;42(10): 954-957, Oct. 2009. ilus
Artigo em Inglês | LILACS | ID: lil-526192

RESUMO

The purpose of the present study was to determine the range of the influence of the baroreflex on blood pressure in chronic renal hypertensive rats. Supramaximal electrical stimulation of the aortic depressor nerve and section of the baroreceptor nerves (sinoaortic denervation) were used to obtain a global analysis of the baroreceptor-sympathetic reflex in normotensive control and in chronic (2 months) 1-kidney, 1-clip hypertensive rats. The fall in blood pressure produced by electrical baroreceptor stimulation was greater in renal hypertensive rats than in normotensive controls (right nerve: -47 ± 8 vs -23 ± 4 mmHg; left nerve: -51 ± 7 vs -30 ± 4 mmHg; and both right and left nerves: -50 ± 8 vs -30 ± 4 mmHg; P < 0.05). Furthermore, the increase in blood pressure level produced by baroreceptor denervation in chronic renal hypertensive rats was similar to that observed in control animals 2-5 h (control: 163 ± 5 vs 121 ± 1 mmHg; 1K-1C: 203 ± 7 vs 170 ± 5 mmHg; P < 0.05) and 24 h (control: 149 ± 3 vs 121 ± 1 mmHg; 1K-1C: 198 ± 8 vs 170 ± 5 mmHg; P < 0.05) after sinoaortic denervation. Taken together, these data indicate that the central and peripheral components of the baroreflex are acting efficiently at higher arterial pressure in renal hypertensive rats when the aortic nerve is maximally stimulated or the activity is abolished.


Assuntos
Animais , Feminino , Masculino , Ratos , Aorta/inervação , Barorreflexo/fisiologia , Pressão Sanguínea/fisiologia , Hipertensão Renal/fisiopatologia , Pressorreceptores/fisiologia , Denervação Autônoma , Doença Crônica , Estimulação Elétrica , Ratos Wistar
4.
Rev. bras. pesqui. méd. biol ; Braz. j. med. biol. res;42(4): 386-396, Apr. 2009. graf, tab
Artigo em Inglês | LILACS | ID: lil-509171

RESUMO

The autonomic nervous system plays an important role in physiological and pathological conditions, and has been extensively evaluated by parametric and non-parametric spectral analysis. To compare the results obtained with fast Fourier transform (FFT) and the autoregressive (AR) method, we performed a comprehensive comparative study using data from humans and rats during pharmacological blockade (in rats), a postural test (in humans), and in the hypertensive state (in both humans and rats). Although postural hypotension in humans induced an increase in normalized low-frequency (LFnu) of systolic blood pressure, the increase in the ratio was detected only by AR. In rats, AR and FFT analysis did not agree for LFnu and high frequency (HFnu) under basal conditions and after vagal blockade. The increase in the LF/HF ratio of the pulse interval, induced by methylatropine, was detected only by FFT. In hypertensive patients, changes in LF and HF for systolic blood pressure were observed only by AR; FFT was able to detect the reduction in both blood pressure variance and total power. In hypertensive rats, AR presented different values of variance and total power for systolic blood pressure. Moreover, AR and FFT presented discordant results for LF, LFnu, HF, LF/HF ratio, and total power for pulse interval. We provide evidence for disagreement in 23 percent of the indices of blood pressure and heart rate variability in humans and 67 percent discordance in rats when these variables are evaluated by AR and FFT under physiological and pathological conditions. The overall disagreement between AR and FFT in this study was 43 percent.


Assuntos
Animais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Ratos , Adulto Jovem , Sistema Nervoso Autônomo/fisiopatologia , Análise de Fourier , Bloqueio Cardíaco/fisiopatologia , Hipertensão/fisiopatologia , Derivados da Atropina/farmacologia , Bloqueio Cardíaco/induzido quimicamente , Frequência Cardíaca/fisiologia , Ratos Endogâmicos SHR , Ratos Wistar , Índice de Gravidade de Doença , Teste da Mesa Inclinada , Adulto Jovem
5.
Braz J Med Biol Res ; 41(10): 849-53, 2008 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-19037531

RESUMO

Malignant hypertension seems to be the consequence of very high blood pressure. Furthermore, an increase in sympathetic and renin-angiotensin system activity is considered to be the main mechanisms producing malignant hypertension. In the present study, 10 offspring of malignant hypertensive (OMH) parents (age 28 +/- 5 years, 7 males, 3 females, 2 white and 8 non-white) and 10 offspring of normotensive (ONT) parents (age 28 +/- 6 years, 2 males, 8 females, 3 white and 7 non-white) were evaluated. The OMH group had significantly higher (P < 0.05) casual blood pressure (125 +/- 10/81 +/- 5 mmHg) compared with ONT (99 +/- 13/67 +/- 5 mmHg). The increase in blood pressure was greater in OMH (Delta SBP = 17 +/- 2 vs Delta SBP = 9 +/- 1 mmHg in ONT) during cold pressor testing, but they had a lower increase in heart rate (Delta HR = 13 +/- 2 vs Delta HR = 20 +/- 3 bpm in ONT) during isometric exercise(handgrip test). Sympathetic activity, measured by microneurography, was significantly higher (P < 0.05) before exercise in OMH (17 +/- 6 vs 11 +/- 4 burst/min in ONT) and exhibited a greater increase (Delta = 18 +/- 10 vs Delta = 8 +/- 3 burst/min in ONT) during isometric exercise. This study showed increased sympathetic activity in OMH before exercise and a greater response during isometric exercise, suggesting an autonomic abnormality before exercise and a greater sympathetic response to physical stress in OMH compared to ONT.


Assuntos
Exercício Físico/fisiologia , Hipertensão Maligna/fisiopatologia , Estresse Fisiológico/fisiologia , Sistema Nervoso Simpático/fisiopatologia , Adulto , Estudos de Casos e Controles , Feminino , Frequência Cardíaca/fisiologia , Humanos , Hipertensão Maligna/sangue , Hipertensão Maligna/genética , Masculino , Pais
6.
Rev. bras. pesqui. méd. biol ; Braz. j. med. biol. res;41(10): 849-853, Oct. 2008. graf, tab
Artigo em Inglês | LILACS | ID: lil-496801

RESUMO

Malignant hypertension seems to be the consequence of very high blood pressure. Furthermore, an increase in sympathetic and renin-angiotensin system activity is considered to be the main mechanisms producing malignant hypertension. In the present study, 10 offspring of malignant hypertensive (OMH) parents (age 28 ± 5 years, 7 males, 3 females, 2 white and 8 non-white) and 10 offspring of normotensive (ONT) parents (age 28 ± 6 years, 2 males, 8 females, 3 white and 7 non-white) were evaluated. The OMH group had significantly higher (P < 0.05) casual blood pressure (125 ± 10/81 ± 5 mmHg) compared with ONT (99 ± 13/67 ± 5 mmHg). The increase in blood pressure was greater in OMH (Ä SBP = 17 ± 2 vs Ä SBP = 9 ± 1 mmHg in ONT) during cold pressor testing, but they had a lower increase in heart rate (Ä HR = 13 ± 2 vs Ä HR = 20 ± 3 bpm in ONT) during isometric exercise (handgrip test). Sympathetic activity, measured by microneurography, was significantly higher (P < 0.05) before exercise in OMH (17 ± 6 vs 11 ± 4 burst/min in ONT) and exhibited a greater increase (Ä = 18 ± 10 vs Ä = 8 ± 3 burst/min in ONT) during isometric exercise. This study showed increased sympathetic activity in OMH before exercise and a greater response during isometric exercise, suggesting an autonomic abnormality before exercise and a greater sympathetic response to physical stress in OMH compared to ONT.


Assuntos
Adulto , Feminino , Humanos , Masculino , Exercício Físico/fisiologia , Hipertensão Maligna/fisiopatologia , Estresse Fisiológico/fisiologia , Sistema Nervoso Simpático/fisiopatologia , Estudos de Casos e Controles , Frequência Cardíaca/fisiologia , Hipertensão Maligna/sangue , Hipertensão Maligna/genética , Pais
7.
Eur J Vasc Endovasc Surg ; 30(5): 469-74, 2005 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-16061402

RESUMO

OBJECTIVE: To determine the relationship between carotid intima-media thickness (IMT), carotid wall shear stress (WSS) and restenosis after femoro-popliteal percutaneous transluminal angioplasty (PTA). PATIENTS AND METHODS: Thirty-one subjects (18 men, 13 women, median age 69 years) treated with femoro-popliteal PTA for symptomatic peripheral arterial occlusive disease were enrolled. On admission, IMT, internal diameter and blood velocity of the common carotid artery (CCA) were assessed by high-resolution ultrasonography. Blood viscosity was measured and carotid WSS was calculated. Patients were followed up for 6 months for the occurrence of significant restenosis (>50%) as documented by duplex ultrasonography. Two patients were lost to follow-up. RESULTS: Fourteen patients (48%) developed restenosis at 6 months. IMT and WSS were not different in patients without and with restenosis (IMT: 0.90 (0.85-0.97) vs. 0.89 (0.84-0.93) mm, p = 0.51; WSS: 14.1 (11.9-19.2) vs. 15.9 (12.8-21.5) dyne/cm2, p = 0.48). The hazard ratio of incident restenosis as estimated by Cox regression analysis was 0.04 for IMT (p = 0.23; 95% CI 0.0001-8.22) and 1.07 for WSS (p = 0.10; 95% CI 0.98-1.17). CONCLUSIONS: In this pilot study involving a limited number of patients, carotid IMT and carotid WSS are not significantly related to restenosis at 6 months after femoro-popliteal PTA. This might be the result of different underlying pathophysiology for atherosclerosis and restenosis.


Assuntos
Angioplastia com Balão , Arteriopatias Oclusivas/terapia , Artéria Carótida Primitiva/patologia , Estenose das Carótidas/patologia , Túnica Íntima/patologia , Túnica Média/patologia , Idoso , Estenose das Carótidas/diagnóstico por imagem , Feminino , Artéria Femoral , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Contagem de Plaquetas , Artéria Poplítea , Estudos Prospectivos , Recidiva , Análise de Regressão , Ultrassonografia Doppler Dupla
8.
Rev. bras. pesqui. méd. biol ; Braz. j. med. biol. res;38(6): 949-957, June 2005. ilus, graf
Artigo em Inglês | LILACS | ID: lil-402663

RESUMO

Arterial baroreflex sensitivity estimated by pharmacological impulse stimuli depends on intrinsic signal variability and usually a subjective choice of blood pressure (BP) and heart rate (HR) values. We propose a semi-automatic method to estimate cardiovascular reflex sensitivity to bolus infusions of phenylephrine and nitroprusside. Beat-to-beat BP and HR time series for male Wistar rats (N = 13) were obtained from the digitized signal (sample frequency = 2 kHz) and analyzed by the proposed method (PRM) developed in Matlab language. In the PRM, time series were low-pass filtered with zero-phase distortion (3rd order Butterworth used in the forward and reverse direction) and presented graphically, and parameters were selected interactively. Differences between basal mean values and peak BP (deltaBP) and HR (deltaHR) values after drug infusions were used to calculate baroreflex sensitivity indexes, defined as the deltaHR/deltaBP ratio. The PRM was compared to the method traditionally (TDM) employed by seven independent observers using files for reflex bradycardia (N = 43) and tachycardia (N = 61). Agreement was assessed by Bland and Altman plots. Dispersion among users, measured as the standard deviation, was higher for TDM for reflex bradycardia (0.60 ± 0.46 vs 0.21 ± 0.26 bpm/mmHg for PRM, P < 0.001) and tachycardia (0.83 ± 0.62 vs 0.28 ± 0.28 bpm/mmHg for PRM, P < 0.001). The advantage of the present method is related to its objectivity, since the routine automatically calculates the desired parameters according to previous software instructions. This is an objective, robust and easy-to-use tool for cardiovascular reflex studies.


Assuntos
Animais , Masculino , Ratos , Barorreflexo/efeitos dos fármacos , Pressão Sanguínea/efeitos dos fármacos , Frequência Cardíaca/efeitos dos fármacos , Reconhecimento Automatizado de Padrão/métodos , Processamento de Sinais Assistido por Computador , Barorreflexo/fisiologia , Pressão Sanguínea/fisiologia , Cardiotônicos/farmacologia , Frequência Cardíaca/fisiologia , Modelos Lineares , Nitroprussiato/farmacologia , Variações Dependentes do Observador , Fenilefrina/farmacologia , Ratos Wistar
9.
Rev. bras. pesqui. méd. biol ; Braz. j. med. biol. res;37(11): 1615-1622, Nov. 2004. tab, graf
Artigo em Inglês | LILACS | ID: lil-385874

RESUMO

The first minutes of the time course of cardiopulmonary reflex control evoked by lower body negative pressure (LBNP) in patients with hypertensive cardiomyopathy have not been investigated in detail. We studied 15 hypertensive patients with left ventricular dysfunction (LVD) and 15 matched normal controls to observe the time course response of the forearm vascular resistance (FVR) during 3 min of LBNP at -10, -15, and -40 mmHg in unloading the cardiopulmonary receptors. Analysis of the average of 3-min intervals of FVR showed a blunted response of the LVD patients at -10 mmHg (P = 0.03), but a similar response in both groups at -15 and -40 mmHg. However, using a minute-to-minute analysis of the FVR at -15 and -40 mmHg, we observed a similar response in both groups at the 1st min, but a marked decrease of FVR in the LVD group at the 3rd min of LBNP at -15 mmHg (P = 0.017), and -40 mmHg (P = 0.004). Plasma norepinephrine levels were analyzed as another neurohumoral measurement of cardiopulmonary receptor response to LBNP, and showed a blunted response in the LVD group at -10 (P = 0.013), -15 (P = 0.032) and -40 mmHg (P = 0.004). We concluded that the cardiopulmonary reflex response in patients with hypertensive cardiomyopathy is blunted at lower levels of LBNP. However, at higher levels, the cardiopulmonary reflex has a normal initial response that decreases progressively with time. As a consequence of the time-dependent response, the cardiopulmonary reflex response should be measured over small intervals of time in clinical studies.


Assuntos
Humanos , Masculino , Feminino , Adulto , Pessoa de Meia-Idade , Barorreflexo , Hipertensão/fisiopatologia , Pressorreceptores/fisiopatologia , Resistência Vascular , Disfunção Ventricular Esquerda/fisiopatologia , Estudos de Casos e Controles , Antebraço/irrigação sanguínea , Hemodinâmica , Hipertensão/sangue , Pressão Negativa da Região Corporal Inferior , Norepinefrina/sangue , Fatores de Tempo , Disfunção Ventricular Esquerda/sangue
10.
Neurol Sci ; 24(3): 159-60, 2003 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-14598065

RESUMO

Four chromosomal loci ( PARK2, PARK6, PARK7, and PARK9) associated with autosomal recessive, early onset parkinsonism are known. We mapped the PARK7 locus to chromosome 1p36 in a large family from a genetically isolated population in the Netherlands, and confirmed this linkage in an Italian family. By positional cloning within the refined PARK7 critical region we recently identified mutations in the DJ-1 gene in the two PARK7-linked families. The function of DJ-1 remains largely unknown, but evidence from genetic studies on the yeast DJ-1 homologue, and biochemical studies in murine and human cell lines, suggests a role for DJ-1 as an antioxidant and/or a molecular chaperone. Elucidating the role of DJ-1 will lead to a better understanding of the pathogenesis of DJ-1-related and common forms of Parkinson's disease.


Assuntos
Cromossomos Humanos Par 1 , Proteínas Oncogênicas/genética , Transtornos Parkinsonianos/genética , Análise Mutacional de DNA , Saúde da Família , Humanos , Peptídeos e Proteínas de Sinalização Intracelular , Mutação , Proteína Desglicase DJ-1
11.
Hypertension ; 38(3 Pt 2): 616-20, 2001 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-11566942

RESUMO

Malignant hypertension is a serious form of arterial hypertension in which the physiopathological mechanisms include increased activity of the sympathetic nervous system, renin angiotensin system, and endothelium dysfunction. Family history of hypertension is an important predictive factor for hypertension and is associated with metabolic and hemodynamic abnormalities. Studies of these abnormalities in malignant hypertensive offspring have not yet been published. Therefore, we studied 42 offspring of malignant hypertensive parents (OMH group: age, 22+/-7 years; 23 male subjects; 27 white) and 35 offspring of normotensive parents (ONT group: age, 21+/-4 years; 23 male subjects; 25 white). All subjects had blood pressure <140/90 mm Hg. We evaluated body mass index; office blood pressure; 24-hour ambulatory and continuous beat-to-beat blood pressure monitoring (Finapres); biochemical analysis, including total cholesterol and fractions, triglycerides, glucose, and insulin; and hormonal analysis, including plasma renin activity, aldosterone, and catecholamines. The subjects were also submitted to cold pressure test and handgrip measurements. The body mass index was significantly higher in the OMH group (24+/-5 kg/m(2)) than in the ONT group (22+/-4 kg/m(2)). The OMH group showed significantly higher blood pressure and heart rate in office and Finapres measurements (P<0.05). In 24-hour ambulatory monitoring, the OMH group presented higher 24-hour blood pressure and heart rate, higher blood pressure during the night, and higher heart rate variability during the day compared with those of the ONT group. They also presented lower HDL cholesterol, higher levels of plasma insulin and norepinephrine, and higher insulin-to-glucose ratio (P<0.05) than the ONT group. There were no differences in the other biochemical parameters measured. In conclusion, OMH subjects show early hemodynamic, neurohumoral, and metabolic alterations that are typical of hypertensive metabolic syndrome.


Assuntos
Hemodinâmica/fisiologia , Hipertensão/fisiopatologia , Adolescente , Adulto , Aldosterona/sangue , Glicemia/metabolismo , Pressão Sanguínea/fisiologia , Colesterol/sangue , Diástole , Saúde da Família , Feminino , Frequência Cardíaca/fisiologia , Humanos , Hipertensão/sangue , Hipertensão/genética , Insulina/sangue , Masculino , Potássio/sangue , Renina/sangue , Sódio/sangue , Estresse Fisiológico/fisiopatologia , Sístole , Triglicerídeos/sangue , Ácido Úrico/sangue
12.
Rev. bras. pesqui. méd. biol ; Braz. j. med. biol. res;33(12): 1491-6, Dec. 2000. graf
Artigo em Inglês | LILACS | ID: lil-274894

RESUMO

To assess the role of angiotensin II in the sensitivity of the baroreflex control of heart rate (HR) in normotensive rats (N = 6) and chronically hypertensive rats (1K1C, 2 months, N = 7), reflex changes of HR were evaluated before and after (15 min) the administration of a selective angiotensin II receptor antagonist (losartan, 10 mg/kg, iv). Baseline values of mean arterial pressure (MAP) were higher in hypertensive rats (195 ± 6 mmHg) than in normotensive rats (110 ± 2 mmHg). Losartan administration promoted a decrease in MAP only in hypertensive rats (16 percent), with no changes in HR. During the control period, the sensitivity of the bradycardic and tachycardic responses to acute MAP changes were depressed in hypertensive rats (~70 percent and ~65 percent, respectively) and remained unchanged after losartan administration. Plasma renin activity was similar in the two groups. The present study demonstrates that acute blockade of AT1 receptors with losartan lowers the MAP in chronic renal hypertensive rats without reversal of baroreflex hyposensitivity, suggesting that the impairment of baroreflex control of HR is not dependent on an increased angiotensin II level


Assuntos
Masculino , Animais , Ratos , Angiotensina II/fisiologia , Anti-Hipertensivos/uso terapêutico , Barorreflexo/efeitos dos fármacos , Frequência Cardíaca/efeitos dos fármacos , Hipertensão Renal/tratamento farmacológico , Losartan/uso terapêutico , Anti-Hipertensivos/farmacologia , Bradicardia/tratamento farmacológico , Doença Crônica , Frequência Cardíaca/efeitos dos fármacos , Losartan/farmacologia , Receptores de Angiotensina/antagonistas & inibidores , Receptores de Angiotensina/metabolismo , Taquicardia/tratamento farmacológico
13.
Can Assoc Radiol J ; 51(3): 163-9, 2000 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-10914081

RESUMO

OBJECTIVE: Patients with cancer require reliable venous access for therapy and phlebotomy. Traditionally, insertion of venous ports has been performed in the operating room. However, the interventional radiology service has recently become involved in the placement of a variety of venous access devices. This study examines the technique and complications associated with the placement of venous ports in the arm for patients with cancer. METHODS: Cook titanium Petite Vital-Ports (Cook Canada, Stouffville, Ont.) were implanted in patients with cancer, and implantation was performed in the medical imaging vascular/interventional suite. Patients were followed prospectively by periodic chart review for a maximum of 42 months after port insertion. Minimum follow-up in patients who did not die from cancer was 6 months. RESULTS: The authors implanted 125 Vital-Ports. The mean duration of port implantation was 265 days (range 2 to 1278 days, total catheter days 33 221). Venous thrombosis developed in 5 patients (4%, or 0.06 episodes/1000 catheter days). Four patients (3.2%, or 0.12 episodes/1000 catheter days) had suspected infection of the port or catheter, and 2 had culture-positive infection (1.6%, or 0.06 episodes/1000 catheter days). Two patients (1.6%, or 0.06 episodes/1000 catheter days) required port or catheter revision owing to mechanical difficulties. CONCLUSION: The Cook titanium Petite Vital-Port, implanted in the arm in the medical imaging vascular/interventional suite, is relatively safe and effective. As a result, it has been widely accepted by the patients and clinicians at the hospital where this study was conducted.


Assuntos
Braço/irrigação sanguínea , Cateterismo Periférico , Cateteres de Demora , Neoplasias/terapia , Radiografia Intervencionista , Adulto , Idoso , Idoso de 80 Anos ou mais , Angiografia , Cateterismo Periférico/efeitos adversos , Cateteres de Demora/efeitos adversos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Trombose/etiologia , Veias
14.
Rev. bras. pesqui. méd. biol ; Braz. j. med. biol. res;33(1): 51-4, Jan. 2000. tab
Artigo em Inglês | LILACS | ID: lil-252256

RESUMO

Although a slightly elevated office blood pressure (BP) has been reported in several studies, little is known about the prolonged resting blood pressure, heart rate (HR) and baroreflex sensitivity (BRS) of prehypertensive subjects with a family history of hypertension. Office blood pressure, prolonged resting (1 h) BP and HR were measured in 25 young normotensives with a positive family history of hypertension (FH+) and 25 young normotensives with a negative family history of hypertension (FH-), matched for age, sex, and body mass index. After BP and HR measurements, blood samples were collected for the determination of norepinephrine, plasma renin activity and aldosterone levels, and baroreflex sensitivity was then tested. Casual BP, prolonged resting BP and heart rate were significantly higher in the FH+ group (119.9 + or - 11.7/78.5 + or - 8.6 mmHg, 137.3 + or - 12.3/74.4 + or - 7.9 mmHg, 68.5 + or - 8.4 bpm) compared to the FH- group (112.9 + or - 11.4/71.2 + or - 8.3 mmHg, 128.0 + or - 11.8/66.5 + or - 7.4 mmHg, 62.1 + or - 6.0 bpm). Plasma norepinephrine level was significantly higher in the FH+ group (220.1 + or - 104.5 pg/ml) than in the FH- group (169.1 + or - 63.3 pg/ml). Baroreflex sensitivity to tachycardia (0.7 + or - 0.3 vs 1.0 + or - 0.5 bpm/mmHg) was depressed in the FH+ group (P<0.05). The FH+ group exhibited higher casual blood pressure, prolonged resting blood pressure, heart rate and plasma norepinephrine levels than the FH- group (P<0.05), suggesting an increased sympathetic tone in these subjects. The reflex tachycardia was depressed in the FH+ group


Assuntos
Feminino , Humanos , Adulto , Adolescente , Barorreflexo , Pressão Sanguínea/fisiologia , Frequência Cardíaca/fisiologia , Hipertensão/genética , Norepinefrina/sangue , Sistema Nervoso Simpático/fisiopatologia , Aldosterona/sangue , Índice de Massa Corporal , Distribuição de Qui-Quadrado , Hipertensão/diagnóstico , Hipertensão/fisiopatologia , Potenciais da Membrana , Renina/sangue , Sensibilidade e Especificidade
15.
Am J Hypertens ; 12(2 Pt 1): 204-8, 1999 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-10090349

RESUMO

Complex arrhythmia is frequent in hemodialysis patients but it is not clear if this is a consequence of dialysis or uremia or is secondary to the hemodynamic and cardiovascular alterations often associated with chronic renal failure. The incidence of complex ventricular arrhythmia (frequent multiform premature beats, couplets, and runs) in 31 subjects who had their uremic status recently corrected by renal transplant (Group 1) and in 23 predialysis (Group 2) and 73 hemodialysis (Group 3) chronic renal failure patients were studied with 24-h Holter monitoring. Patients were not receiving antiarrhythmic drugs or digitalis and significant coronary artery disease was excluded by clinical and noninvasive methods. Complex arrhythmia was two times more frequent in dialysis patients but the difference did not reach statistical significance (Group 1: 16%; Group 2: 17%; Group 3: 34%; chi2 4.9, P = .086). The stepwise model of logistic regression analysis identified systolic blood pressure (odds ratio 1.015, 95% confidence interval [CI] 1.001-1.027, P = .03) and left ventricular systolic dysfunction (odds ratio 7.04, 95% CI 1.3-36.7, P = .02) as the only factors that independently influenced the probability of complex arrhythmia. Age, gender, race, diabetes, smoking status, body mass index, diastolic blood pressure, serum creatinine, hematocrit, left ventricular mass index, and use of diuretics, beta-blockers, angiotensin converting enzyme (ACE) inhibitors, sympatolytics, and calcium channel blockers did not influence the occurrence of complex arrhythmia. The data indicate that blood pressure and myocardial dysfunction are more important determinants of complex arrhythmia than dialysis or uremia in chronic renal disease patients.


Assuntos
Pressão Sanguínea/fisiologia , Falência Renal Crônica/fisiopatologia , Transplante de Rim/fisiologia , Diálise Renal , Taquicardia Ventricular/fisiopatologia , Adulto , Ecocardiografia , Eletrocardiografia Ambulatorial , Feminino , Humanos , Hipertensão/complicações , Hipertensão/diagnóstico por imagem , Hipertensão/fisiopatologia , Falência Renal Crônica/complicações , Falência Renal Crônica/terapia , Masculino , Razão de Chances , Fatores de Risco , Taquicardia Ventricular/complicações , Taquicardia Ventricular/diagnóstico por imagem , Disfunção Ventricular Esquerda/diagnóstico por imagem , Disfunção Ventricular Esquerda/etiologia , Disfunção Ventricular Esquerda/fisiopatologia
16.
Rev. bras. pesqui. méd. biol ; Braz. j. med. biol. res;32(3): 361-9, Mar. 1999.
Artigo em Inglês | LILACS | ID: lil-230466

RESUMO

Baroreflex sensitivity was studied in the same group of conscious rats using vasoactive drugs (phenylephrine and sodium nitroprusside) administered by three different approaches: 1) bolus injection, 2) steady-state (blood pressure (BP) changes produced in steps), 3) ramp infusion (30 s, brief infusion). The heart rate (HR) responses were evaluated by the mean index (mean ratio of all HR changes and mean arterial pressure (MAP) changes), by linear regression and by the logistic method (maximum gain of the sigmoid curve by a logistic function). The experiments were performed on three consecutive days. Basal MAP and resting HR were similar on all days of the study. Bradycardic responses evaluated by the mean index (-1.5 ñ 0.2, -2.1 ñ 0.2 and -1.6 ñ 0.2 bpm/mmHg) and linear regression (-1.8 ñ 0.3, -1.4 ñ 0.3 and -1.7 ñ 0.2 bpm/mmHg) were similar for all three approaches used to change blood pressure. The tachycardic responses to decreases of MAP were similar when evaluated by linear regression (-3.9 ñ 0.8, -2.1 ñ 0.7 and -3.8 ñ 0.4 bpm/mmHg). However, the tachycardic mean index (-3.1 ñ 0.4, -6.6 ñ 1 and -3.6 5 0.5 bpm/mmHg) was higher when assessed by the steady-state method. The average gain evaluated by logistic function (-3.5 ñ 0.6, -7.6 ñ 1.3 and -3.8 ñ 0.4 bpm/mmHg) was similar to the reflex tachycardic values, but different from the bradycardic values. Since different ways to change BP may alter the afferent baroreceptor function, the MAP changes obtained during short periods of time (up to 30 s: bolus and ramp infusion) are more appropriate to prevent the acute resetting. Assessment of the baroreflex sensitivity by mean index and linear regression permits a separate analysis of gain for reflex bradycardia and reflex tachycardia. Although two values of baroreflex sensitivity cannot be evaluated by a single symmetric logistic function, this method has the advantage of better comparing the baroreflex sensitivity of animals with different basal blood pressures


Assuntos
Animais , Masculino , Ratos , Barorreflexo , Determinação da Pressão Arterial/métodos , Pressão Sanguínea/fisiologia , Estado de Consciência , Frequência Cardíaca/fisiologia , Pressorreceptores/fisiologia , Análise de Variância , Pressão Sanguínea/efeitos dos fármacos , Bradicardia , Frequência Cardíaca/efeitos dos fármacos , Modelos Lineares , Nitroprussiato/farmacologia , Fenilefrina/farmacologia , Ratos Wistar , Taquicardia
17.
Cardiology ; 92(2): 93-8, 1999.
Artigo em Inglês | MEDLINE | ID: mdl-10702650

RESUMO

Malignant hypertension is associated with high mortality and morbidity usually caused by cardiovascular events. The course and prognosis of malignant hypertension patients treated with renal replacement therapy has not been thoroughly investigated. In the present work, we compared the clinical evolution and survival of 24 end-stage renal failure malignant hypertension patients with that of a group of individually matched renal failure patients admitted to the same dialysis center during a period of 21 years. Survival rates at 1, 5 and 8 years were 87, 82 and 50% for malignant hypertension patients and 87, 75 and 65% for controls, respectively (p = 0.766, NS). Nonfatal cardiovascular complications occurred in 2 individuals of each group. The most important cause of death in both groups was cardiovascular. The frequency of fatal cardiovascular events was similar in the two groups: 64% of deaths for malignant hypertension and 71% for controls (NS). In conclusion, previous malignant hypertension did not increase the risk of patients in long-term hemodialysis in our series.


Assuntos
Hipertensão Maligna/mortalidade , Falência Renal Crônica/mortalidade , Falência Renal Crônica/terapia , Diálise Renal , Adolescente , Adulto , Idoso , População Negra , Criança , Comorbidade , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Distribuição por Sexo , Taxa de Sobrevida , Tempo , Resultado do Tratamento , População Branca
18.
Rev. bras. pesqui. méd. biol ; Braz. j. med. biol. res;31(9): 1213-20, sept. 1998. tab, graf
Artigo em Inglês | LILACS | ID: lil-222968

RESUMO

The arterial baroreceptor reflex system is one of the most powerful and rapidly acting mechanisms for controlling arterial pressure. The purpose of the present review is to discuss data relating sympathetic activity to the baroreflex control of arterial pressure in two different experimental models: neurogenic hypertension by sinoaortic denervation (SAD) and high-renin hypertension by total aortic ligation between the renal arteries in the rat. SAD depresses baroreflex regulation of renal sympathetic activity in both the acute and chronic phases. However, increased sympathetic activity (100 percent) was found only in the acute phase of sinoaortic denervation. In the chronic phase of SAD average discharge normalized but the pattern of discharges was different from that found in controls. High-renin hypertensive rats showed overactivity of the renin angiotensin system and a great depression of the baroreflexes, comparable to the depression observed in chronic sinoaortic denervated rats. However, there were no differences in the average tonic sympathetic activity or changes in the pattern of discharges in high-renin rats. We suggest that the difference in the pattern of discharges may contribute to the increase in arterial pressure lability observed in chronic sinoaortic denervated rats.


Assuntos
Animais , Barorreflexo/fisiologia , Pressão Sanguínea/fisiologia , Hipertensão Renal/fisiopatologia , Hipertensão/fisiopatologia , Pressorreceptores/fisiopatologia , Sistema Nervoso Simpático/fisiopatologia , Doença Crônica , Denervação Muscular , Pressorreceptores/fisiologia , Nó Sinoatrial/inervação , Nó Sinoatrial/fisiologia , Sistema Nervoso Simpático/efeitos dos fármacos , Sistema Nervoso Simpático/fisiologia
19.
In. Schiabel, Homero; Slaets, Annie France Frère; Costa, Luciano da Fontoura; Baffa Filho, Oswaldo; Marques, Paulo Mazzoncini de Azevedo. Anais do III Fórum Nacional de Ciência e Tecnologia em Saúde. Säo Carlos, s.n, 1996. p.117-118, graf.
Monografia em Português | LILACS | ID: lil-236274

RESUMO

O objetivo desse estudo foi avaliar a atividade neurogênica dos pressoreceptores (APR, registrada no nervo aórtico) e a atividade simpática periférica (ASR, registrada no nervo simpático renal), considerando-se a ocorrência e distribuição nos ciclos cardíacos e nas fases sistólica e diastólica. Foram estudados ratos normais anestesiados e ratos acordados submetidos à desnervação sino-aórtica (DSA) nas fases aguda e crônica após a desnervação. Os resultados obtidos sugerem que a falta de sincronismo entre a atividade simpática e os ciclos da pressão arterial contribuem para as alterações encontradas na pressão sanguínea na ausência dos pressoreceptores


Abstract - The aim of this study was to analyze the neurogenic activity of baroreceptors (recorded on the aortic nerve, APR) and peripheral sympathetic activity (recorded on the renal nerve. AsR ) with regard to its occurence and distribution in relation to the cardiac cycle and the systolic and diastolic phases of it. Normal anesthetized rats and awaken sino aortic denervated (SAD) rats were studied. The analysis showed that the existing synchronism between sympathetic activity and arterial pressure pulses found in normal rats was absent in SAD rats. These results suggest that the Jack of synchronism between sympathetic activity and cardiac cycles may contribute to the alterations in blood pressure observed in the absence of baroreceptors


Assuntos
Pressorreceptores/fisiologia , Nervos Periféricos , Pressão Arterial/fisiologia , Sistema Nervoso Simpático , Anestesia , Pressão Atmosférica
20.
Hypertension ; 26(6 Pt 2): 1207-10, 1995 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-7498998

RESUMO

Malignant hypertension (MH) is a severe complication of untreated arterial hypertension that damages the vascular system. It is often accompanied by disturbances in lipid metabolism that could contribute to its pathophysiology. We examined chylomicron metabolism in MH patients using a triglyceride-rich emulsion known to mimic natural chylomicrons when injected into the bloodstream. The emulsion was labeled with [3H]triolein and [14C]cholesteryl oleate and injected intravenously into 15 normolipidemic MH patients aged 29 to 56 years (8 men) for comparison with 17 healthy control subjects. Consecutive plasma samples were taken at regular intervals during 1 hour for determination of the disappearance curves of the labels. The fractional clearance rate of the [3H]triolein emulsion in MH patients was twice as small as that of control subjects (0.061 +/- 0.012 and 0.141 +/- 0.074 min-1, respectively). On the other hand, [14C]cholesteryl oleate fractional clearance rate was not statistically different in MH patients and control subjects (0.032 +/- 0.004 and 0.056 +/- 0.014 min-1, respectively). These results indicate that in MH, lipolysis (measured by the fractional clearance rate of [3H]triolein) is pronounced diminished, whereas the removal of the remnant particles (measured by the fractional clearance rate of [14C]cholesteryl oleate) is not importantly affected. In conclusion, there is an alteration in the circulatory transport of dietary lipids that may be an important component in the vascular disease associated with MH.


Assuntos
Quilomícrons/metabolismo , Hipertensão Maligna/metabolismo , Adulto , Ésteres do Colesterol/metabolismo , HDL-Colesterol/sangue , LDL-Colesterol/sangue , VLDL-Colesterol/sangue , Interpretação Estatística de Dados , Gorduras na Dieta/metabolismo , Emulsões/administração & dosagem , Feminino , Humanos , Hipertensão Maligna/sangue , Injeções Intravenosas , Lipólise , Masculino , Pessoa de Meia-Idade , Modelos Biológicos , Triglicerídeos/sangue , Triglicerídeos/metabolismo , Trioleína/metabolismo
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