Strain differences in baroceptor reflex in adult wistar kyoto rats

OBJECTIVES: A 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. METHODS: Male 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 (&#916;HR/&#916;MAP) 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. RESULTS: Approximately 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. CONCLUSION: There is variability regarding baroreflex sensitivity among WKY rats from the same laboratory

Vehicle influence on potassium replacement effectiveness in hypokalemic rats

INTRODUCTION: Patients who undergo cardiac surgery are commonly treated with diuretic therapy for the management of volume overload. The concern of hypokalemia important in the adult population submitted to cardiac surgery has been described. Intravenous potassium (K+) replacement dilution is only recommended with sodium chloride 0.9% solution (SF0.9%), likely due to the putative effects of glucose solution 5% (SG5%) on insulin secretion, which influence K+ replacement quality. However, it is not yet experimentally proved the influence of SF0.9% and SG5% on K+ replacement quality. Objectives: To evaluate the effects of different vehicles of K+ replacement on blood K+ levels in furosemide hypokalemic rats. METHODS: Male Wistar rats divided into four groups: K+SF, K+SG, SF and SG. Jugular vein cannulation for K+ replacement and femoral vein cannulation for blood analysis. Furosemide (50mg/kg) to induce hypokalemia. We prepared the following solutions: vehicle 1.6mL (SF0.9% or SG5%) + 0.4 mL de K+ (19.1%) and for control groups only vehicle 2 mL. Furosemide (50 mg/kg) was used to induce hypokalaemia, it was analyzed potassium plasmatic levels 24 hours before furosemide injection, 24 hours after furosemide injection and 30 minutes after post-replacement. RESULTS: There was no significative difference in blood K+ levels before furosemide administration, after hypokalemic induction and after K+ replacement among all groups. Only SF+K presented blood Na+ levels increaseafter K+ replacement (P<0.05). CONCLUSION: K+ replacement in different vehicles did not affect blood K+ levels in ratsINTRODUÇÃO: Pacientes após cirurgia cardíaca são comumente tratados com diuréticos para controle de volume plasmático. A preocupação de distúrbios hipocalêmicos em adultos antes, durante ou após a cirurgia já foi ressaltada anteriormente, visto o risco de arritmias cardíacas. Clinicamente, a diluição da solução de potássio (K+) para administração por via intravenosa, em situações que requerem a sua reposição é realizada utilizando-se soro fisiológico (SF) ao invés de soro glicosado 5% (SG5%), possivelmente em vista de poder ocorrer estimulação da secreção de insulina, que interferiria sobre a qualidade da reposição de K+. Porém, não está comprovado experimentalmente se o SF e SG5% poderiam realmente interferir na qualidade da reposição de potássio em ratos com hipocalemia. OBJETIVO: Analisar a influência da reposição de K+ diluído em diferentes veículos sobre as concentrações plasmáticas de K+([K+]p) em ratos submetidos a hipocalemia induzida por furosemida. MÉTODOS: Ratos Wistar adultos foram divididos em quatro grupos: K++SF, K++SG, SF e SG. Foi realizada a canulação da veia jugular para reposição e da veia femoral para coleta de sangue. O diurético furosemida na dose de 50mg/kg foi usado para induzir hipocalemia, foi analisado nível plasmático de potássio 24 h antes da injeção de furosemida, 24 h pós-indução e 30 minutos pós-reposição. RESULTADOS: Os níveis da [K+] pós-injeção de furosemida sofreram redução, comparado aos valores basais (pré-furosemida) em todos os grupos. Entretanto, os níveis [K+] retornaram aos valores basais tanto nos grupos que receberam K++SF ou K++SG, o que não foi observado nos grupos que receberam apenas SF e SG. Quanto ao Na+ plasmático, somente o grupo K+SF apresentou aumento após reposição. CONCLUSÃO: A reposição de K+ diluído tanto em SF quanto SG parece não afetar a qualidade da reposição de K+ plasmático em ratosUniversidade Federal de São Paulo (UNIFESP) Departamento de MedicinaFaculdade de Medicina do ABC Departamento de FisiologiaUNIFESP, Depto. de MedicinaSciEL

Congenital diaphragmatic Bochdaleck hernia: case report

Congenital diaphragmatic Bochdaleck hernia is an anatomical defect of the diaphragm, which allows protrusion of abdominal viscera into the chest, causing serious pulmonary and cardiac complications in the neonate. In this study we aimed to present a case of congenital Bochdaleck hernia. We investigated a 40 weeks old child, with a pregnancy carried out in a public hospital in Passo Fundo, Rio Grande do Sul, Brazil. We suggest that if diagnosis occurs in the prenatal period, the prognosis of this disease improves. As a consequence, it allows the parity of the fetus to occur in a higher complexity center, optimizing the chances of survival. © 2012 Lava et al.; licensee BioMed Central Ltd

Cardiac baroreflex is already blunted in eight weeks old spontaneously hypertensive rats

Background. The literature did not evidence yet with which age spontaneously hypertensive rats (SHR) start to present baroreflex reduction. We endeavored to evaluate the baroreflex function in eight-week-old SHR. Methods. Male Wistar Kyoto (WKY) normotensive rats and SHR aged eight weeks were studied. Baroreflex was calculated as the variation of heart rate (HR) divided by the mean arterial pressure (MAP) variation (HR/MAP) tested with a depressor dose of sodium nitroprusside (SNP, 50 g/kg) and with a pressor dose of phenylephrine (PHE, 8 g/kg) in the right femoral venous approach through an inserted cannula in the animals. Significant differences for p < 0.05. Results. Baseline MAP (p < 0.0001) and HR (p = 0.0028) was higher in SHR. Bradycardic peak was attenuated in SHR (p < 0.0001), baroreflex gain tested with PHE was also reduced in the SHR group (p = 0.0012). PHE-induced increase in MAP was increased in WKY compared to SHR (p = 0.039). Bradycardic reflex responses to intravenous PHE was decreased in SHR (p < 0.0001). Conclusion. Eight weeks old SHR already presents impairment of the parasympathetic component of baroreflex. © 2010 Cisternas et al; licensee BioMed Central Ltd

Evaluation of physiological parameters before and after respiratory physiotherapy in newborns with acute viral bronchiolitis

Abstract Background Acute viral bronchiolitis is a respiratory disease with high morbidity that affects newborn in the first two years of life. Its treatment with physiotherapy has been highlighted as an important tool, however, there is no consensus regarding its effects on patients improvement. We aimed to evaluate the physiological parameters before and after the procedure respiratory therapy in newborn with acute viral bronchiolitis. Method This was a cross sectional observational study in 30 newborns with acute viral bronchiolitis and indicated for physiotherapy care in a hospitalized Urgency and Emergency Unit. It was collected the clinical data of newborn through evaluation form, and we measured heart rate (HR), oxygen saturation (SpO2) and respiratory rate (RR). We measured the variables before physiotherapy treatment, 3, 6 and 9 minutes after the physiotherapy treatment. Results There has been no change in HR, however, we observed a decrease in RR at 6 and 9 min compared to 3 min and increase in SpO2 at 3, 6 and 9 min compared to before physiotherapy. Conclusion Respiratory physiotherapy may be an effective therapy for the treatment of newborn with Acute Viral Bronchitis

Cardiac baroreflex is already blunted in eight weeks old spontaneously hypertensive rats

Abstract Background The literature did not evidence yet with which age spontaneously hypertensive rats (SHR) start to present baroreflex reduction. We endeavored to evaluate the baroreflex function in eight-week-old SHR. Methods Male Wistar Kyoto (WKY) normotensive rats and SHR aged eight weeks were studied. Baroreflex was calculated as the variation of heart rate (HR) divided by the mean arterial pressure (MAP) variation (ΔHR/ΔMAP) tested with a depressor dose of sodium nitroprusside (SNP, 50 μg/kg) and with a pressor dose of phenylephrine (PHE, 8 μg/kg) in the right femoral venous approach through an inserted cannula in the animals. Significant differences for p < 0.05. Results Baseline MAP (p < 0.0001) and HR (p = 0.0028) was higher in SHR. Bradycardic peak was attenuated in SHR (p < 0.0001), baroreflex gain tested with PHE was also reduced in the SHR group (p = 0.0012). PHE-induced increase in MAP was increased in WKY compared to SHR (p = 0.039). Bradycardic reflex responses to intravenous PHE was decreased in SHR (p < 0.0001). Conclusion Eight weeks old SHR already presents impairment of the parasympathetic component of baroreflex