ABSTRACT
O desoxinivalenol (DON), principal micotoxina encontrada em trigo e derivados, tem sido associado a surtos de gastroenterite, distúrbios gastrointestinais e diarreia em humanos e animais. Para controle das micotoxinas em alimentos há a necessidade de métodos confiáveis e precisos. Desta forma, o presente trabalho teve como objetivo validar metodologia analítica para análise de DON em amostras de trigo e produtos comercializados na cidade de São Paulo. O método foi validado de acordo com os parâmetros linearidade, recuperação, precisão, limites de detecção (LD) e quantificação (LQ). A extração do DON foi realizada por homogeneização com água deionizada, seguida de centrifugação, filtração e purificação em coluna de imunoafinidade. A separação e quantificação foram conduzidas por cromatografia líquida com detecção por ultravioleta (CLAE-UV). A curva analítica, obtida pelo método dos mínimos quadrados, foi linear com coeficiente de correlação de 0,9995. A recuperação média foi de 102% e o coeficiente de variação de 2,4% para a concentração de 877 µg/kg. Os LD e LQ foram de 60 e 200 µg/kg, respectivamente. Os cromatogramas obtidos não apresentaram interferências na região do tempo de retenção do DON (9,7 min), sendo o método proposto considerado adequado para a quantificação de desoxinivalenol em trigo e produtos a base de trigo
Subject(s)
Chromatography, High Pressure Liquid , Chromatography, Liquid , Diarrhea , FoodABSTRACT
Little is known about age-related differences in short-term effects of estradiol on ischemia-reperfusion (I/R) insults. The present study was designed to evaluate the effects of short-term treatment with estradiol on reperfusion arrhythmias in isolated hearts of 6-7-week-old and 12-14-month-old female rats. Wistar rats were sham-operated, ovariectomized and treated with vehicle or ovariectomized and treated with 17β-estradiol (E2; 5 µg·100 g-1·day-1) for 4 days. Hearts were perfused by the Langendorff technique. Reperfusion arrhythmias, i.e., ventricular tachycardia and/or ventricular fibrillation, were induced by 15 min of left coronary artery ligation and 30 min of reperfusion. The duration and incidence of I/R arrhythmias were significantly higher in young rats compared to middle-aged rats (arrhythmia severity index: 9.4 ± 1.0 vs 3.0 ± 0.3 arbitrary units, respectively, P < 0.05). In addition, middle-aged rats showed lower heart rate, systolic tension and coronary flow. Four-day E2 treatment caused an increase in uterine weight. Although E2 administration had no significant effect on the duration of I/R arrhythmias in middle-aged rats, it induced a marked reduction in the rhythm disturbances of young rats accompanied by a decrease in heart rate of isolated hearts. Also, this reduction was associated with an increase in QT interval. No significant changes were observed in the QT interval of middle-aged E2-treated rats. These data demonstrate that short-term estradiol treatment protects against I/R arrhythmias in hearts of young female rats. The anti-arrhythmogenic effect of estradiol might be related to a lengthening of the QT interval.
Subject(s)
Animals , Female , Arrhythmias, Cardiac/prevention & control , Estradiol/pharmacology , Myocardial Reperfusion Injury/physiopathology , Age Factors , Arrhythmias, Cardiac/physiopathology , Coronary Circulation/drug effects , Coronary Circulation/physiology , Electrocardiography , Estradiol/administration & dosage , Ovariectomy , Rats, Wistar , Ventricular Function, Left/drug effectsABSTRACT
Calcium ion participates in the regulation of neural transmission and the presynaptic release of neurotransmitters. It is also involved in epileptic events, cardiac arrhythmias and abnormal conduction of stimuli. The purpose of the present study was to evaluate the effects of nifedipine, a calcium channel blocker, on epileptic seizures and on reperfusion arrhythmias in rats prone to audiogenic epileptic seizures (Wistar audiogenic rats, WAR) and in normal Wistar rats (N = 6/group). The seizure severity index was applied after an intraperitoneal injection of 20 or 40 mg/kg nifedipine (N20 and N40 groups, respectively). The Langendorff technique was used to analyze cardiac function, as well as the incidence and severity of the reperfusion arrhythmias after ligature and release of the left coronary artery in rats treated or not with nifedipine. We found that nifedipine treatment decreased seizure severity (0.94 ± 0.02 for WAR; 0.70 ± 0.10 for WAR + N20; 0.47 ± 0.08 for WAR + N40) and increased the latent period (13 ± 2 s for WAR; 35 ± 10 s for WAR + N20; 48 ± 7 s for WAR + N40) for the development of seizures in WAR. Furthermore, the incidence and severity of the reperfusion arrhythmias were lower in WAR and normal Wistar rats injected with nifedipine. In WAR, these effects were mediated, at least in part, by a decrease in heart rate. Thus, our results indicate that nifedipine may be considered to be a potential adjuvant drug for epilepsy treatment, especially in those cases associated with cardiac rhythm abnormalities.