170 research outputs found

    Urotensin II-Induced Increase in Myocardial Distensibility Is Modulated by Angiotensin II and Endothelin-1

    Get PDF
    Endogenous regulators, such as angiotensin-II (AngII), endothelin-1 (ET-1) and urotensin-II (U-II) are released from various cell types and their plasma levels are elevated in several cardiovascular diseases. The present study evaluated a potential crosstalk between these systems by investigating if the myocardial effects of U-II are modulated by AngII or ET-1. Effects of U-II (10(-8), 10(-7), 10(-6) M) were tested in rabbit papillary muscles in the absence and in the presence of losartan (selective AT, receptor antagonist), PD-145065 (nonselective ET-1 receptors antagonist), losartan plus PD-145065, AngII or ET-1. U-II promoted concentration-dependent negative inotropic and lusitropic effects that were abolished in all experimental conditions. Also, U-II increased resting muscle length up to 1.008 +/- 0.002 L/L(max). Correcting it to its initial value resulted in a 19.5 +/- 3.5 % decrease of resting tension, indicating increased muscle distensibility. This effect on muscle length was completely abolished in the presence of losartan and significantly attenuated by PD-145065 or losartan plus PD-145065. This effect was increased in the presence of AngII, resulting in a 27.5 +/- 3.9 % decrease of resting tension, but was unaffected by the presence of ET-1. This study demonstrated an interaction of the U-II system with the AngII and ET-1 systems in terms of regulation of systolic and diastolic function

    Modulation of Myocardial Stiffness by beta-Adrenergic Stimulation Its Role in Normal and Failing Heart

    Get PDF
    The acute effects of ß-adrenergic stimulation on myocardial stiffness were evaluated. New-Zealand white rabbits were treated with saline (control group) or doxorubicin to induce heart failure (HF) (DOXO-HF group). Effects of isoprenaline (10 -10-1 -5 M), a non-selective ß-adrenergic agonist, were tested in papillary muscles from both groups. In the control group, the effects of isoprenaline were also evaluated in the presence of a damaged endocardial endothelium, atenolol (ßi-adrenoceptor antagonist), ICI-118551 (ßz-adrenoceptor antagonist), KT-5720 (PKA inhibitor), L-NNA (NO-synthase inhibitor), or indomethacin (cyclooxygenase inhibitor). Passive length-tension relations were constructed before and after adding isoprenaline (10 -5 M). In the control group, isoprenaline increased resting muscle length up to 1.017±0.006 L/L max. Correction of resting muscle length to its initial value resulted in a 28.5±3.1% decrease of resting tension, indicating decreased muscle stiffness, as confirmed by the isoprenaline-induced right-downward shift of the passive lengthtension relation. These effects were modulated by ßr and ß 2adrenoceptors and PKA. In DOXO-HF group, the effect on myocardial stiffness was significantly decreased. We conclude that ß-adrenergic stimulation is a relevant mechanism of acute neurohumoral modulation of the diastolic function. Furthermore, this study clarifies the mechanisms by which myocardial stiffness is decreased. (c) 2011 Institute of Physiology v.v.i., Academy of Sciences of the Czech Republic, Prague, Czech Republic

    Echocardiographic evaluation including tissue Doppler imaging in New Zealand white rabbits sedated with ketamine and midazolam

    Get PDF
    Limited data are available on the use of more recent echocardiographic parameters in the rabbit. Echocardiographic examination, including conventional echocardiography and tissue Doppler imaging (TDI), was performed on 26 male New Zealand white rabbits under ketamine-midazolam sedation. Particular emphasis was placed on the more recent systolic and diastolic parameters, such as myocardial performance index (Tei index) and mitral annular motion (from septal and lateral sides of the left ventricle) obtained using pulsed TDI. Parameters that assessed systolic and diastolic function (fractional shortening, Tei index, and maximal mitral E- and A-wave velocities) were comparable to those reported in the literature for rabbits in the awake state. The less cardiodepressive anaesthetic protocol could offer a good alternative in performing echocardiographic evaluation whenever such caution is necessary. TDI is feasible in healthy rabbits and potentially suitable for the investigation of left ventricle systolic and diastolic function

    Seropositivity for Coxiella burnetii in Wild Boar (Sus scrofa) and Red Deer (Cervus elaphus) in Portugal

    Get PDF
    Q fever is caused by the pathogen Coxiella burnetii and is a zoonosis that naturally infects goats, sheep, and cats, but can also infect humans, birds, reptiles, or arthropods. A survey was conducted for the detection of antibodies against C. burnetii in a sample of 617 free-ranging wild ruminants, 358 wild boar (Sus scrofa) and 259 red deer (Cervus elaphus), in east-central Portugal during the 2016-2022 hunting seasons. Only adult animals were sampled in this study. Antibodies specific to C. burnetii were detected using a commercial enzyme-linked immunosorbent assay (ELISA; IDVet(R), Montpellier, France) according to the manufacturer's instructions. The seroprevalence of C. burnetii infection was 1.5% (n = 9; 95% confidence interval [CI]: 0.7-2.8%). Antibodies against C. burnetii were detected in 4/358 wild boar (1.1%; 95% CI: CI: 0.3-2.8%) and 5/259 red deer (1.9%; 0.6-4.5%). Results of the present study indicate that antibodies against C. burnetii were present in wild boar and red deer in Portugal. These findings can help local health authorities to focus on the problem of C. burnetii in wildlife and facilitate the application of a One Health approach to its prevention and control

    Prevalence and Risk Factors for Hepatitis E Virus in Wild Boar and Red Deer in Portugal

    Get PDF
    Hepatitis E virus (HEV) is a zoonotic foodborne virus with an annual infection prevalence of 20 million human cases, which seriously affects public health and economic development in both developed and developing countries. To better understand the epidemiology of HEV in Central Portugal, a cross-sectional study was conducted from 2016 to 2023 with sera samples from wild ungulates. The seroprevalence and risk factors for HEV seropositivity were evaluated in the present study. Specifically, antibodies against HEV were determined by a commercial enzyme-linked immune-sorbent assay (ELISA). Our results show that in the 650 sera samples collected from 298 wild red deer and 352 wild boars in Portugal, 9.1% red deer and 1.7% wild boar were positive for antibodies to HEV. Regarding age, the seropositivity in juvenile wild ungulates was 1.3%, whereas it was 7.2% in adults. Logistic regression models investigated risk factors for seropositivity. The odds of being seropositive was 3.6 times higher in adults than in juveniles, and the risk was 4.2 times higher in red deer than in wild boar. Both wild ungulate species were exposed to HEV. The higher seroprevalence in red deer suggests that this species may make a major contribution to the ecology of HEV in Central Portugal. Further research is needed to understand how wildlife affects the epidemiology of HEV infections in Portugal.This research was funded by projects UIDP/00772/2020 and LA/P/0059/2020, funded by the Portuguese Foundation for Science and Technology (FCT). Sérgio Santos-Silva would like to thank Fundação para a Ciência e a Tecnologia (FCT) for the financial support of his Ph.D. work under the scholarship 2021.09461.BD contract through the Maria de Sousa-2021 program

    O HIPOTÁLAMO DORSOMEDIAL E A ORGANIZAÇÃO DA RESPOSTA CARDIOVASCULAR AO ESTRESSE EMOCIONAL: UMA PERSPECTIVA FUNCIONAL

    Get PDF
    Emotional stress results in activation of specific pathways into central nervous system, which produces autonomic, behavioral and endocrine responses. It is known that repetitive or continuous exposition to stress situations may result in various pathologic states, for example, arterial hypertension. Classically, the hypothalamus plays an essential role in the integration of physiological responses to emotional stress. Recent studies demonstrate that a specific nucleus from hypothalamus, the dorsomedial hypothalamus (DMH), is an essential component of central pathways that mediate the cardiovascular response to emotional stress. Inhibition of neurons in this area reduces the increases in heart rate and blood pressure in rats submitted to emotional stress paradigms. Conversely, pharmacological activation of DMH neurons evokes increases on heart rate, blood pressure, adrenocorticotrophic hormone, locomotor activity and sympathetic activity. The similarity of this response with that produced during emotional stress suggests that this area is crucial in the integration of the physiological responses to emotional stress. The present review will discuss the central pathways used by DMH in the organization of the cardiovascular response to emotional stress.O estresse emocional resulta em ativação de vias específicas do sistema nervoso central, que produzem respostas autonômicas, comportamentais e endócrinas. Sabe-se que situações de estresse recorrentes ou prolongadas podem resultar em vários estados patológicos, como por exemplo, a hipertensão arterial. O Hipotálamo tem papel fundamental na integração das respostas fisiológicas ao estresse emocional. Particularmente, estudos têm mostrado que um núcleo específico do hipotálamo, o hipotálamo dorsomedial (DMH), é um componente fundamental das vias centrais mediadoras das respostas cardiovasculares ao estresse emocional. A inibição dos neurônios dessa área reduz os aumentos de freqüência cardíaca e de pressão arterial em ratos quando submetidos à situações de estresse emocional. Ao contrário, a ativação farmacológica dos neurônios do DMH produz aumento na frequência cardíaca, pressão arterial, hormônio adrenocorticotrópico (ACTH), atividade locomotora e na atividade simpática para diversos leitos vasculares. A similaridade dessa resposta com aquela produzida durante a situação real de estresse emocional sugere que esta área é fundamental na integração da resposta fisiológica ao estresse. A presente revisão tem como objetivo mostrar, através de resultados de estudos recentes, as vias centrais utilizadas pelo DMH na organização da resposta cardiovascular ao estresse emocional

    A avaliação perceptiva de atributos paralinguísticos e extralinguísticos na fala de uma comunidade de prática

    Get PDF
    Este trabalho tem como objetivo investigar as impressões causadas, pelo falar de sujeitos de uma comunidade de prática caiçara, em grupos de ouvintes de três localidades diversas, por meio da aplicação de um questionário de diferencial semântico, o qual contém descritores referentes a atributos paralinguísticos e extralinguísticos: psicológicos, sociais, culturais, físicos e econômicos. Trata-se de uma pesquisa de natureza sociofonética perceptiva que compreende uma tarefa de produção e uma de percepção e utiliza o método de análise estatística multidimensional. Os resultados indicam que a fala da comunidade caiçara não causou nenhuma estranheza ou incompreensão, mas foi considerada pouco agradável pelos juízes de todas as localidades. Com base nas variáveis estatisticamente significantes, os caiçaras, a partir da percepção da sua maneira de falar, foram julgados como pessoas que exercem trabalhos manuais, apresentam situação financeira baixa e são ingênuos, simplórios e humildes

    Exposure of humans to the zoonotic nematode Dirofilaria immitis in Northern Portugal

    Get PDF
    Dirofilariosis caused by Dirofilaria immitis (heartworm) is a zoonosis, considered an endemic disease of dogs and cats in several countries of Western Europe, including Portugal. This study assesses the levels of D. immitis exposure in humans from Northern Portugal, to which end, 668 inhabitants of several districts belonging to two different climate areas (Csa: Bragança, Vila Real and Csb: Aveiro, Braga, Porto, Viseu) were tested for anti-D. immitis and anti-Wolbachia surface proteins (WSP) antibodies. The overall prevalence of seropositivity to both anti-D. immitis and WSP antibodies was 6.1%, which demonstrated the risk of infection with D. immitis in humans living in Northern Portugal. This study, carried out in a Western European country, contributes to the characterisation of the risk of infection with D. immitis among human population in this region of the continent. From a One Health point of view, the results of the current work also support the close relationship between dogs and people as a risk factor for human infectio
    corecore