1,720,966 research outputs found
Efeitos do exercício físico e da Terapia Estrogênica sobre a reatividade vascular de aorta de ratas espontaneamente hipertensas Ovariectomizadas: papel do Sistema Renina-angiotensina
No full textCardiovascular diseases are the major source of morbidity and mortality in most industrialized countries including in postmenopausal women, period characterized by a decrease in the estrogens production. Renin Angiotensin System (RAS) has been highlighted as a major mediator in the pathophysiology of many diseases, such as hypertension. Experimental and clinical studies showed upregulation of RAS after menopause. Although many experimental works report beneficial effects of hormonal replacement with estrogens, mainly 17β-Estradiol (E2), in the reduction of the risk to develop cardiovascular diseases, the results of clinical trials are so far to be conclusive. In this context, lifestyle modifications are necessary as the incorporation of regular physical training. Many studies have appointed that physical training can influence positively on the main cardiovascular risk factors. The aim of this study was to analyze the effects of chronic swimming training and estrogen therapy on vascular reactivity of aorta rings in ovariectomized spontaneously hypertensive rats (SHR) ovariectomized rats and the expression of RAS components in aorta. The animals were divided into five groups as following: Sham (S), Ovariectomized (OVX), ovariectomized treated with E2 (OTE2), ovariectomized+swimming (ON) and ovariectomized treated with E2 plus swimming (OE2+N). E2 replacement was performed by s.c. injection containing 5 µg of 17β-Estradiol, three times a week. Swimming training was conducted by sixty minutes daily in a continuous way and five times per week. Both, training and E2 therapy started seven days after ovariectomy and lasted eight weeks. Forty eight hours after the last treatment and/or training session, the animals had the systolic blood pressure measured, then were sacrificed and blood was collected to measure Angiotensin II plasma levels by radioimmunoassay (RIA)and to carry out two different protocols of analysis. For the functional study with aortic rings we evaluated the response to Ang II and Angiotensin-(1- 7) and the analysis of RAS proteins expression were made by Western Blotting method, which was performed in aorta artery. The results demonstrated that both exercise and E2 increased Ang II plasma levels. However, the systolic blood pressure was attenuated by treatments. The OVX group showed increase in the constrictor response to Ang II and decrease dilatator response to Ang-(1- 7), that was reverted by swimming training or E2 therapy associated to swimming. Moreover, ON and OE2+N groups showed increase in the AT2 and Mas receptor expression. On the other hand, the ON showed increase in the superoxide dismutase (SOD) anti-oxidant enzyme and only the groups treated with E2 showed increase on eNOS expression. Therefore, according to the results of the present study, we conclude that both, swimming training and E2 treatment may play a role in the cardioprotection and the chronic practice of physical exercise can be a feasible alternative in relation to estrogen therapy in post-menopausal women. However, the association between physical exercise and E2 therapy not promotes additional adaptations in the parameters analyzed.As doenças cardiovasculares representam as principais causas de morbidade e mortalidade no mundo, inclusive em mulheres no período pós-menopausa. Com a diminuição na produção dos estrógenos, observa-se o aparecimento e a elevação de vários fatores que podem aumentar o risco de desenvolvimento dessas doenças. Dentre esses fatores, o aumento da atividade ou up regulation do Sistema Renina-Angiotensina (SRA) tem se destacado como um importante mediador na fisiopatologia de várias doenças, tal qual, a hipertensão. Apesar de vários estudos experimentais relatarem efeitos benéficos da reposição hormonal com estrogênio, especificamente 17β-estradiol (E2), sobre a redução do risco cardiovascular, os resultados de estudos clínicos são inconclusivos. Desta forma, modificações no estilo de vida se fazem necessárias, como a incorporação da prática regular de exercícios físicos. Muitos estudos têm demonstrado que o exercício físico pode influenciar positivamente sobre os principais fatores de risco cardiovascular, inclusive em mulheres na pós-menopausa. O objetivo do presente estudo foi analisar os efeitos do treinamento físico crônico de natação e da terapia estrogênica sobre a reatividade vascular de aorta de ratas espontaneamente hipertensas (SHR) ovariectomizadas com foco na modulação efetuada pelo SRA. Os experimentos foram conduzidos com ratas SHR Sham e ovariectomizadas, as quais foram divididas aleatoriamente em cinco grupos: SHAM (S), ovariectomizadas (OVX), ovariectomizadas+TE2 (OE2), ovariectomizadas+natação (ON) e ovariectomizadas TE2+N (OE2+N). A reposição com E2 foi realizada por meio de injeções s.c. contendo 5 µg de 17β-estradiol três vezes por semana. O protocolo de treinamento de natação foi realizado por sessenta minutos diários, de forma continua, cinco vezes por semana. Tanto a terapia quanto o treinamento tiveram duração de oito semanas. Quarenta e oito horas após a última sessão de treinamento e/ou tratamento, as ratas tiveram a Pressão Arterial Sistólica (PAS) aferida e após sacrificadas, o sangue foi coletado para dosagem de angiotensina II (Ang II). Para o estudo funcional de reatividade de aorta, avaliou-se a resposta vasoconstritora à angiotensina II e vasodilatadora à Ang-(1-7), ainda efetuando bloqueios farmacológicos para elucidar o mecanismo de ação. A avaliação da expressão das proteínas do SRA em aorta foi realizada por Western Blotting. Os resultados encontrados demonstram que, o grupo ON e OE2+N apresentaram aumento nos níveis plasmáticos de Ang II, que não foi acompanhado por aumento na PAS. A ovariectomia causou um aumento da resposta vasoconstritora a Ang II e diminuição da vasodilatação de Ang-(1-7), que foi prevenida pelo exercício físico ou pela sua associação com a TE2. Além disso, o abrandamento da resposta vasoconstritora a Ang II, assim como o aumento da vasodilatação a Ang-(1-7) parece ter ocorrido por um mecanismo envolvendo o receptor AT2 e Mas, que tiveram sua expressão aumentada no grupo ON e OE2+N. No grupo ON a eficiência funcional destes receptores foi auxiliada pelo aumento na capacidade anti-oxidante, efetuada pela superóxido dismutase. Pôde-se concluir que tanto o treinamento físico quanto a reposição com E2 exercem efeitos cardioprotetores, e a prática regular do exercício físico pode ser uma excelente alternativa à terapia estrogênica em mulheres na pós-menopausa, haja vista que a associação da TE2 ao exercício não promoveu efeitos somatórios
Participação do peptídeo natriurético atrial na hipotensão e bradicardia de ratos espontaneamente hipertensos após treinamento físico crônico em diferentes modalidades
No full textBackground – Acutely the atrial natriuretic peptide (ANP) has an effect of renal natriuresis and diuresis, vasodilatation, resulting in decrease of blood pressure. However, the responses of this peptide and of his receptors associated to different chronics physical training in the hypertension remain unknown. Methods and results - The aim was identified the possible alterations in the synthesis and release of atria ANP, expression and affinity of the NPR-A, NPRC in the kidneys and fat tissue of spontaneously hypertensive rats (SHR) submitted to swimming or running physical training. Male SHR were subjected to 8-week of swimming or running under similar intensities. Radioimmunoassay was used to measure ANP levels. mRNA ANP in the atria, such as mRNA of natriuretic peptide receptor (NPR)-A and NPR-C in the kidneys and fat tissue was determined by real time- polymerase chain reaction. The autoradiography was used to determine the sensitivity of binding to ANP receptors. Both groups shown decrease in the blood pressure, but only swim group shown bradycardia. A significant increase of ANP expression in the right atrium and plasma levels was found in the swim group. Hence, not was found alteration in the expression of NPR-C in fat tissue, but the binding of ANP was altered in this tissue in the swim group. The index between NPR-A/NPR-C in the kidneys was significantly lower in run group. Conclusions: The mechanism hypotensor and bradycardic in hypertensive rats shown differences, with the ANP can be involved in this alterations by swimming, but not in the running training.Agudamente o Peptídeo Natriurético Atrial (ANP) tem um efeito natriurético e diurético renal e vasodilatação, consequentemente resultando em diminuição da pressão arterial. Contudo, o comportamento deste peptídeo e de seus receptores associado ao treinamento físico crônico em condições de hipertensão permanece desconhecido.
Métodos e Resultados: O objetivo do presente estudo foi identificar as possíveis alterações na síntese e secreção do ANP, expressão e sensibilidade dos receptores dos peptídeos natriuréticos (NPR)-A e NPR-C nos rins e tecido adiposo de ratos espontaneamente hipertensos (SHR) submetidos ao treinamento físico de natação ou corrida. SHR machos foram submetidos ao treinamento físico de corrida ou natação por 8 semanas com intensidades similares. Radioimunoensaio foi utilizado para as dosagens de ANP. RNAm do ANP atrial, assim como RNAm de NPR-A e NPR-C nos rins e no tecido adiposo visceral foram mensurados pelo reação de polimerização em cadeia em tempo real (RT-PCR). A autoradiografia foi utilizada para mensurar a sensibilidade do binding dos NPR no rim e tecido adiposo. Ambos os grupos apresentaram diminuição da pressão arterial, mas somente no grupo natação houve bradicardia. Houve aumento significativo da expressão de ANP no átrio direito e nos níveis plasmáticos deste peptídeo. Ainda, não foi encontrada diferença estatisticamente significativa na expressão do NPR-C no tecido adiposo. Todavia, o binding do ANP pelo NPR-C neste tecido foi alterado pela natação. A razão entre NPR-A/NPR-C no tecido nos rins foi estatisticamente menor no grupo corrida.
Conclusão: O mecanismo hipotensor e bradicárdico em ratos hipertensos submetidos ao treinamento físico apresentou diferença, podendo o ANP estar envolvido nestas adaptações no grupo natação, mas não nos animais treinados com corrida
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Concentra??o de Angiotensinas e atividades da ECA e ECA 2 circulantes de pacientes em hemodi?lise
No full textLinha de pesquisa: Sistema Renina Angiotensina.Submitted by Nivaldo Melo ([email protected]) on 2019-09-10T18:10:37Z
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Previous issue date: 2018Introdu??o - A Doen?a Cardiovascular (DCV) ? a principal causa de morte entre os pacientes
portadores de Doen?a Renal Cr?nica Terminal (DRCT) em Hemodi?lise (HD). A
desregula??o do Sistema Renina Angiotensina (SRA) exerce significativa influ?ncia na
progress?o da DCV e renal.
Objetivo - Analisar o efeito da sess?o de hemodi?lise sobre os componentes do SRA dos
pacientes DRCT e estudar a repercuss?o dos f?rmacos sobre esse sistema.
M?todos - Este estudo caracterizado como observacional anal?tico transversal, avaliou 87
pacientes DRCT em hemodi?lise. Os participantes do estudo tiveram o sangue coletado
imediatamente antes e ap?s a primeira sess?o de hemodi?lise da semana, no qual realizamos a
an?lise da atividade das enzimas, ECA e ECA 2, por m?todo fluorim?trico e da concentra??o
plasm?tica de angiotensinas, Angiotensina I, Angiotensina II e Angiotensina-(1-7), por meio
da espectrometria LC-MS/MS. Tamb?m realizamos essas mesmas an?lises dividindo os
pacientes em grupos conforme os f?rmacos utilizados, a saber: Controle- (sem antihipertensivos), Beta-bloqueador, Beta-bloqueador+iECA e Beta-bloqueador+Bloq.AT1.
Resultados ? Encontramos aumento da atividade da ECA no per?odo p?s-dial?tico. Quando
estratificamos nossos pacientes de acordo com os f?rmacos utilizados, observamos que
ocorreu diminui??o na atividade da ECA nos grupos Beta-bloqueador, Beta-bloqueador
+iECA e Beta-bloqueador+Bloq.AT1. Em rela??o a ECA2, nossos resultados
mostraram diminui??o de atividade no per?odo p?s-dial?tico. Ap?s estratifica??o de acordo
com os f?rmacos utilizados, observamos redu??o apenas no grupo Beta-bloq+ Bloq. AT1. Em
rela??o ?s angiotensinas, n?o observamos diferen?as na concentra??o plasm?tica de Ang I e
Ang-(1-7). No entanto, ocorreu diminui??o nos n?veis plasm?ticos de Ang II no per?odo p?sdial?tico. Ao analisarmos os diferentes grupos, evidenciamos diminui??o nos n?veis
plasm?ticos de Angiotensina II nos grupos Beta-bloqueador+iECA e Betabloqueador+Bloq.AT1.
Conclus?es - Demonstramos que a hemodi?lise interfere no SRA dos pacientes DRCT,
aumentando a atividade da ECA e diminuindo a atividade da ECA2 e a concentra??o
plasm?tica da Ang II. E ainda, que o uso de f?rmacos Beta-bloqueadores, inibidores da ECA e
Bloqueadores do Receptor AT1 est?o associados com altera??es significativas dos
componentes deste sistema, dentre as quais, destacamos diminui??o na atividade da ECA em
pacientes em uso de Beta-bloqueador associado ao iECA e aumento na atividade da ECA 2
naqueles em uso de Beta-bloqueador associado a Bloqueador do Receptor AT1. Considerando a cl?nica, nosso estudo abre uma lacuna para discuss?o de poss?veis mudan?as de conduta
relacionadas ? terapia medicamentosa como, por exemplo, hor?rio de administra??o dos
f?rmacos, suplementa??o de dose ap?s sess?o de hemodi?lise, que podem beneficiar os
pacientes DRCT, minimizando o impacto da doen?a e eficientizando o tratamento. Por fim,
enquanto perspectivas futuras, nosso estudo inicia o entendimento da modula??o da
hemodi?lise e terapia farmacol?gica sobre o SRA em pacientes portadores de DRCT.Disserta??o (Mestrado) ? Programa Multic?ntrico de P?s-gradua??o em Ci?ncias Fisiol?gicas, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2018.Introduction - Cardiovascular disease (CVD) is the leading cause of death among patients
with End Stage Renal Disease (ESRD) on hemodialysis. Deregulation of Renin Angiotensin
System (RAS) exerts a significant influence on the progression of CVD and renal.
Objective - To analyze the effect of the hemodialysis session on the components of the RAS
of the ESRD patients and to study the repercussion of the drugs on this system.
Methods - This cross-sectional observational study evaluated 87 patients on hemodialysis.
The study participants had blood collected immediately before and after the first session of
hemodialysis of the week, in which we performed the analysis of enzyme activity, ACE and
ACE 2, by fluorimetric method and the plasma concentration of angiotensins, Angiotensin I,
Angiotensin II and Angiotensin- (1-7), by means of LC-MS / MS spectrometry. We also
performed these same analyzes by dividing the patients into groups according to the drugs
used, namely: Control- (without antihypertensives), Beta-blocker, Beta-blocker + ACEI and
Beta-blocker + Bloq.AT1.
Results - We found an increase in ACE activity in the post-dialytic period. When we
stratified our patients according to the drugs used, we observed a decrease in ACE activity in
the beta-blocker groups, Beta-blocker + ACEi and Beta-blocker. According to ACE2, our
results showed a decrease in activity in the post-dialytic period. After stratification according
to the drugs used, we observed reduction only in the group Beta-block + Block. AT1.
Regarding angiotensins, we did not observe differences in the plasma concentration of Ang I
and Ang- (1-7). However, there was a decrease in plasma levels of Ang II in the post-dialytic
period. When analyzing the different groups, we showed a decrease in plasma levels of
Angiotensin II in the beta-blocker + iACE groups, and Beta-blocker + Block. AT1.
Conclusion - We demonstrated that hemodialysis interferes in the RAS of the ESRD patients,
increasing the ACE activity and decreasing the activity of ACE2 and the plasma concentration
of Ang II. Furthermore, the use of Beta-blockers, ACE inhibitors and AT1 Receptor Blockers
is associated with significant alterations in the components of this system, among which, we
highlight a decrease in ACE activity in patients using Beta-blocker associated with ACE
inhibitors and increased ACE 2 activity in patients receiving Beta-blocker associated with
AT1 Receptor Blocker. Considering the clinic, our study opens a gap for discussion of
possible changes in conduct related to drug therapy, such as schedule of drug administration,
dose supplementation after hemodialysis session, which may benefit the ESRD patients,
minimizing the impact of the disease and efficient treatment. Finally, as future perspectives, our study begins the understanding of modulation of hemodialysis and pharmacological
therapy on RAS in patients with ESRD
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