Clin Invest Med 2009; 32 (6): E251-E257. AbstractPurpose: To compare baroreflex sensitivity among conscious rats of the same strain. Methods: Male WKY rats (eight weeks old) were studied. Cannulas were inserted into the abdominal aortic artery through the right femoral artery to measure mean arterial pressure (MAP) and heart rate (HR). Baroreflex gain was calculated as the ratio between variation of HR in function of the MAP variation (ΔHR/ΔMAP) tested with a depressor dose of sodium nitroprusside (SNP, 50µg/kg, iv) and with a pressor dose of phenylephrine (PE, 8µg/kg, iv). We divided the rats into four groups: 1) Low bradycardic baroreflex (LB), BG between -1 and -2 bpm/mmHg tested with PE; 2) High bradycardic baroreflex (HB), BG < -2 bpm/mmHg tested with PE; 3) Low tachycardic baroreflex (LT), BG between -1 and -2 bpm/mmHg tested with SNP and; 4) High tachycardic baroreflex (HT), BG < -2 bpm/ mmHg tested with SNP. Significant differences were considered for p<0.05.Results: Approximately 82% of the rats presented reduced bradycardic reflex while 22 showed attenuated tachycardic reflex. No alterations were noted regarding basal MAP and HR, tachycardic and bradycardic peak and HR range. Conclusions: There was alteration in baroreflex sensitivity among rats of the same strain. Care should be taken when interpreting studies employing WKY as a control for the SHR.In 1963, Okamoto and Aoki 1 reported that they had selectively bred Wistar rats to be spontaneously hypertensive. Established as an inbred strain in 1969 at the National Institutes of Health (NIH), the spontaneously hypertensive rat (SHR) remains the most widely studied animal model of essential hypertension (i.e., persistent high blood pressure of unknown causation), and the strain presents similar characteristic to hypertension in humans. As controls for the SHR, most workers have employed normotensive descendants of Wistar rats that NIH investigators obtained in 1971 from the colony in Kyoto from which the SHR strain was originally derived (Wistar-Kyoto rats, WKY). 2 Baroreflex function is one of the body's homeostatic mechanisms to sustain arterial pressure. It offers a negative feedback loop in which the increased arterial pressure reflexively causes blood pressure to de-
Previous events evidence that sudden cardiac death (SCD) in athletes is still a reality and it keeps challenging cardiologists. Considering the importance of SCD in athletes and the requisite for an update of this matter, we endeavored to describe SCD in athletes. The Medline (via PubMed) and SciELO databases were searched using the subject keywords "sudden death, athletes and mortality". The incidence of SCD is expected at one case for each 200,000 young athletes per year. Overall it is resulted of complex dealings of factors such as arrhythmogenic substrate, regulator and triggers factors. In great part of deaths caused by heart disease in athletes younger than 35 years old investigations evidence cardiac congenital abnormalities. Athletes above 35 years old possibly die due to impairments of coronary heart disease, frequently caused by atherosclerosis. Myocardial ischemia and myocardial infarction are responsible for the most cases of SCD above this age (80%). Pre-participatory athletes' evaluation helps to recognize situations that may put the athlete's life in risk including cardiovascular diseases. In summary, cardiologic examinations of athletes' pre-competition routine is an important way to minimize the risk of SCD.
OBJECTIVESA subset of normotensive Sprague–Dawley rats show lower baroreflex sensitivity; however, no previous study investigated whether there are differences in baroreflex sensitivity within this subset. Our study compared baroreflex sensitivity among conscious rats of this specific subtype.METHODSMale Wistar Kyoto (WKY) rats (16 weeks old) were studied. Cannulas were inserted into the abdominal aortic artery through the right femoral artery to measure mean arterial pressure (MAP) and heart rate (HR). Baroreflex gain was calculated as the ratio between change in HR and MAP variation (ΔHR/ΔMAP) in response to a depressor dose of sodium nitroprusside (SNP, 50 μg/kg, i.v.) and a pressor dose of phenylephrine (PE, 8 μg/kg, i.v.). Rats were divided into four groups: 1) low bradycardic baroreflex (LB), baroreflex gain (BG) between -1 and -2 bpm/mmHg tested with PE; 2) high bradycardic baroreflex (HB), BG < -2 bpm/mmHg tested with PE; 3) low tachycardic baroreflex (LT), BG between -1 and -2 bpm/mmHg tested with SNP and; 4) high tachycardic baroreflex (HT), BG < -2 bpm/mmHg tested with SNP. Significant differences were considered for p < 0.05.RESULTSApproximately 37% of the rats showed a reduced bradycardic peak, bradycardic reflex and decreased bradycardic gain of baroreflex while roughly 23% had a decreased basal HR, tachycardic peak, tachycardic reflex and reduced sympathetic baroreflex gain. No significant alterations were noted with regard to basal MAP.CONCLUSIONThere is variability regarding baroreflex sensitivity among WKY rats from the same laboratory.
RESUMOIntrodução: a encefalopatia hipóxico isquêmica neonatal é uma doença devastadora para o cérebro do recém-nascido. Nas últimas duas décadas, as pesquisas experimentais trouxeram grande avanço nos conhecimentos fisiopatológicos. Para a integridade neuronal, é necessária energia suficiente para a célula manter o equilíbrio iônico. A hipotermia tem sido estudada como um método com alto grau de neuroproteção na hipóxia-isquemia (HI). Objetivo: verificar a potencialidade terapêutica da hipotermia como tratamento da encefalopatia hipóxico-isquêmica em recém-nascidos. Método: foram consultadas as bases de dados do Medline, Lilacs, Scielo e JCR-ISI. As consultas incluíram artigos registrados entre 1993 e 2008 no idioma Português, Inglês e Espanhol. Discussão: encefalopatia hipóxico-isquêmica neonatal é complicação imediata à asfixia grave e pode causar graus variados de dano cerebral. As características do dano hipóxico isquêmico indicam que existe um período intermediário, em que é possível intervir interrompendo a cadeia de eventos que levam a destruição celular definitiva. Com a finalidade de proteger o cérebro dos insultos isquêmicos, utilizam-se drogas e diferentes procedimentos, tais como manitol, removedores de radicais livres, antagonistas de receptores opiáceos, supressores de metabolismo e hipotermia para minimizar as lesões. Conclusão: o resfriamento cerebral é a conduta terapêutica promissora em reduzir danos cerebrais em recém-nascidos. Palavras-chave:Recém-nascido; hipotermia; paralisia cerebral; fisiopatologia e encefalopatia. Rev Bras Crescimento Desenvolvimento Hum. 2008; 18(3): 346-358 ARTIGO DE REVISÃO REVIEW ARTICLE
Introdução. Shiatsu é pressão com os dedos aplicados em pontos reflexos. O objetivo é verificar a influência do Shiatsu sobre a pressão arterial sistêmica. Método. A população é constituída por amostra de conveniência, com sete indivíduos de ambos os sexos, idade entre 18 a 40 anos, sem histórico de variação de pressão arterial. A pressão arterial foi aferida em seis momentos, sendo três antes e três após a aplicação do Shiatsu. Resultado. Houve variação da pressão arterial na 1a mensuração (p < 0,05), sendo que nos demais momentos de mensuração não ocorreram mudanças na pressão arterial. Conclusão. A terapêutica com Shiatsu produziu alterações na primeira mensuração da pressão arterial.
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