Acute blood volume expansion delays the gastrointestinal transit of a charcoal meal in awake rats

The present study evaluates the effect of blood volume expansion on the gastrointestinal transit of a charchoal meal (2.5 ml of an aqueous suspension consisting of 5 percent charcoal and 5 percent gum arabic) in awake male Wistar rats (200-270 g). On the day before the experiments, the rats were anesthetized with ether, submitted to left jugular vein cannulation and fasted with water ad libitum until 2 h before the gastrointestinal transit measurement. Blood volume expansion by iv infusion of 1 ml/min Ringer bicarbonate in volumes of 3, 4 or 5 percent body weight delayed gastrointestinal transit at 10 min after test meal administration by 21.3-26.7 percent (P<0.05), but no effect was observed after 1 or 2 percent body weight expansion. The effect of blood volume expansion (up to 5 por cento body weight) on gastrointestinal transit lasted for at least 60 min (P<0.05). Mean arterial pressure increased transiently and central venous pressure increased and hematocrit decreased (P<0.05). Subdiaphragmatic vagotomy and yohimbine (3 mg/kg) prevented the delay caused by expansion on gastrointestinal transit, while atropine (0.5 mg/kg), L-NAME (2 mg/kg), hexamethonium (10 mg/kg), prazosin (1 mg/kg) or propranolol (2 mg/kg) were ineffective. These data show that blood volume expansion delays the gastrointestinal transit of a charcoal meal and that vagal and yohimbine-sensitive pathways appear to be involved in this phenomenon. The delay in gastrointestinal transit observed here, taken together with the modifications of gastrointestinal permeability to salt and water reported by others, may be part of the mechanisms involved in liquid excess management

Effect of pyloroplasty and fundectomy on the delay of gastric emptying and gastrointestinal transit of liquid elicited by acute blood volume expansion in awake rats

We evaluated the effects of fundectomy and pyloroplasty on the delay of gastric emptying (GE) and gastrointestinal (GI) transit of liquid due to blood volume (BV) expansion in awake rats. Male Wistar rats (N=76, 180-250 g) were first submitted to fundectomy (N=26), Heinecke-Mikulicz pyloroplasty (N=25) or SHAM laparotomy (N=25). After 6 days, the left external jugular vein was cannulated and the animals were fasted for 24 h with water ad libitum. The test meal was administered intragastrically (1.5 ml of a phenol red solution, 0.5 mg/ml in 5 percent glucose) to normovolemic control animals and to animals submitted to BV expansion (Ringer-bicarbonate, iv infusion, 1 ml/min, volume up to 5 percent body weight). BV expansion decreased GE and GI transit rates in SHAM laparotomized animals by 52 and 35.9 percent (P<0.05). Fundectomy increased GE and GI transit rates by 61.1 and 67.7 percent (P<0.05) and prevented the effect of expansion on GE but not on GI transit (13.9 percent reduction, P<0.05). Pyloroplasty also increased GE and GI transit rates by 33.9 and 44.8 percent (P<0.05) but did not prevent the effect of expansion on GE or GI transit (50.7 and 21.1. percent reduction, P<0.05). Subdiaphragmatic vagotomy blocked the effect of expansion on GE and GI transit in both SHAM laparotomized animals and animals submitted to pyloroplasty. In conclusion 1) the proximal stomach is involved in the GE delay due to BV expansion but is not essential for the establishment of a delay in GI transit, which suggests the activation of intestinal resistances, 2) pyloric modulation was not apparent, and 3) vagal pathways are involved.

Biodisponibilidade de zinco em dieta regional de Säo Paulo / Zinc bioavailability in the regional diet of Säo Paulo

A biodisponibilidade de zinco em dieta regional de Säo Paulo, da populaçäo com renda menor que 2(dois) salários mínimos, foi estudada em ratos alinos Wistar, recém-desmamados, com peso ao redor de 47.0g. Foram formados três grupos de animais, um experimental, que recebeu raçäo à base da dieta regional de Säo Paulo (DRSP), ad libitum, e os outros dois contrôles, que receberam raçäo à base de caseína suplementada com metionina (CA), "pair feeding" e ad libitum, por um período de 60 dias. As raçöes continham 11% de proteína e 11 mg de zinco/Kg. Para se avaliar a biodisponibilidade de zinco utilizou-se o Indice de absorçäo aparente de zinco e o nível de zinco na carcaça (AU). Observou-se que a biodisponibilidade de zinco da raçäo DRSP é baixa quando comparada com a raçäo contrôle CA. Houve uma correlaçäo positiva significativa entre a quantidade absorvida de zinco e o nível de zinco na carcaça

Alcoolismo em trabalhadores da zona urbana e rural. Uma experiencia em Brasil. / Alcoholism in rural and urban workers. An experience in Brazil

O alcoolismo e o maior problema de farmacodependencia da America Latina. Suas consequencias irreversiveis sobre o organismo geralmente aparecem apos 10 anos, e como sao doencas graves, o habito deve ser interrompido antes do aparecimento dessas lesoes cronicas irreversiveis