Association of exercise training and angiotensin-converting enzyme 2 activator improves baroreflex sensitivity of spontaneously hypertensive rats

The present study sought to determine cardiovascular effects of aerobic training associated with diminazene aceturate (DIZE), an activator of the angiotensin converting enzyme 2, in spontaneously hypertensive rats (SHRs). Male SHRs (280–350 g) were either subjected to exercise training or not (sedentary group). The trained group was subjected to 8 weeks of aerobic training on a treadmill (five times a week, lasting 60 min at an intensity of 50–60% of maximum aerobic speed). In the last 15 days of the experimental protocol, these groups were redistributed into four groups: i) sedentary SHRs with daily treatment of 1 mg/kg DIZE (S+D1); ii) trained SHRs with daily treatment of 1 mg/kg DIZE (T+D1); iii) sedentary SHRs with daily treatment of vehicle (S+V); and iv) trained SHRs with daily treatment of vehicle (T+V). After treatment, SHRs were anesthetized and subjected to artery and femoral vein cannulation prior to the implantation of ECG electrode. After 24 h, mean arterial pressure (MAP) and heart rate (HR) were recorded; the baroreflex sensitivity and the effect of double autonomic blockade (DAB) were evaluated in non-anesthetized SHRs. DIZE treatment improved baroreflex sensitivity in the T+D1 group as compared with the T+V and S+D1 groups. The intrinsic heart rate (IHR) and MAP were reduced in T+D1 group as compared with T+V and S+D1 groups. Hence, we conclude that the association of exercise training with DIZE treatment improved baroreflex function and cardiovascular regulation.

Diagnóstico da hepatite C em pacientes com doença renal crônica em hemodiálise: qual a melhor estratégia? / Diagnosis of hepatitis C in hemodialysis patients with end-stage renal disease (ESRD): what is the best strategy?

hepatite (HCV), comparados à população em geral, face à exposição frequente ao sangue e à contaminação nosocomial. Entretanto, o diagnóstico da hepatite C nesses pacientes é dificultado por sintomas inespecíficos, valores normais de alanina aminotransferase (ALT), na maioria dos casos, sorologia falso-negativa e baixa viremia. Objetivo: definir e avaliar a acurácia dos métodos diagnósticos da hepatite C em pacientes em HD. Métodos: foram avaliados 500 pacientes com DRC em HD, com anti HCV negativo, histórico e prospectivo de três meses, e avaliação de uma amostra de HCV RNA qualitativo e ALT mensal durante o seguimento. Foram excluídos pacientes com diagnóstico prévio de hepatite B e C, HIV, transplantados, em diálise peritoneal e com acesso venoso por cateter duplo-lúmen. Resultados: o tempo médio de HD foi de 48,8 ± 41,2 meses; ALT revelou-se normal em 92%; anti-HCV e HCV RNA negativos em 99,8% dos pacientes; apenas um paciente (0,2%) apresentou viremia positiva, ALT normal e anti HCV falso-negativo durante o período de seguimento. Conclusões: o teste anti-HCV e a ALT não detectaram precocemente a hepatite C em paciente renal crônico com viremia positiva, o que pode ser explicado pelo comprometimento da resposta imune associada à uremia, ou devido ao período prolongado de janela imunológica antes da soroconversão. Entretanto, o valor preditivo negativo do anti-HCV foi alto, sugerindo que uma redução no intervalo de seis meses da dosagem do anti-HCV pode ser uma estratégia para o monitoramento e a detecção precoce da hepatite C nesses pacientes

Introduction: Patients with end-stage renal disease (ESRD) on hemodialysis (HD) are at a higher risk of infection with hepatitis C virus (HCV), when compared to the general population, due to frequent blood exposure and nosocomial infections. However, the diagnosis of hepatitis C in those patients is very difficult due to non-specific symptoms, normal alanine aminotransferase (ALT) levels, in most cases, false-negative serology, and low viral load. Objective: To define and evaluate the accuracy of hepatitis C diagnostic methods on HD patients. Methods: Five hundred HD patients with ESRD, negative anti-HCV in the past, and, for the next three months, underwent monthly qualitative HCV RNA and ALT testing during follow-up. Patients with a diagnosis of hepatitis B and C, HIV, with kidney grafts, in peritoneal dialysis, and with venous access with double-lumen catheter were excluded. Results: Mean time of HD was 48.8 ± 41.2 months; it was detected normal ALT in 92% of patients; negative anti-HCV and HCV RNA in 99.8% of patients; only one patient (0.2%) showed positive viremia, normal ALT, and false-negative anti-HCV during the follow-up period. Conclusions: Anti-HCV and ALT did not allow early detection of hepatitis C in a patient with ESRD and positive viremia, which can be explained by the disruption of the immune response associated with uremia or due to the prolonged immunologic window before seroconversion. However, anti-HCV showed a high negative predictive value, suggesting that a reduction in the six-month interval of the anti-HCV test could be a strategy for monitoring and early detection of hepatitis C in those patients

Lesions of the commissural subnucleus of the nucleus of the solitary tract increase isoproterenol-induced water intake

The nucleus of the solitary tract (NTS) is the primary site of the cardiovascular afferent information about arterial blood pressure and volume. The NTS projects to areas in the central nervous system involved in cardiovascular regulation and hydroelectrolyte balance, such as the anteroventral third ventricle region and the lateral parabrachial nucleus. The aim of the present study was to investigate the effects of electrolytic lesion of the commissural NTS on water and 0.3 M NaCl intake and the cardiovascular responses to subcutaneous injection of isoproterenol. Male Holtzman rats weighing 280 to 320 g were submitted to sham lesion or electrolytic lesion of the commissural NTS (N = 6-15/group). The sham-lesioned rats had the electrode placed along the same coordinates, except that no current was passed. Water intake induced by subcutaneous isoproterenol (30 µg/kg body weight) significantly increased in chronic (15 days) commissural NTS-lesioned rats (to 2.4 ± 0.2 vs sham: 1.9 ± 0.2 mL 100 g body weight-1 60 min-1). Isoproterenol did not induce any sodium intake in sham or in commissural NTS-lesioned rats. The isoproterenol-induced hypotension (sham: -27 ± 4 vs commissural NTS-lesioned rats: -22 ± 4 mmHg/20 min) and tachycardia (sham: 168 ± 10 vs commissural NTS: 144 ± 24 bpm/20 min) were not different between groups. The present results suggest that the commissural NTS is part of an inhibitory neural pathway involved in the control of water intake induced by subcutaneous isoproterenol, and that the overdrinking observed in lesioned rats is not the result of a cardiovascular imbalance in these animals.