Parâmetros hemodinâmicos e ventilatórios em coelhos anestesiados com isoflurano, submetidos à ventilação controlada à pressão com ou sem PEEP / Hemodynamic and ventilatory parameters in rabbits anesthetized with isoflurane submitted to pressure controlled ventilation with or without PEEP

Foi comparada a ventilação controlada à pressão com ou sem pressão positiva expiratória final (PEEP), em coelhos, distribuídos em três grupos, denominados GP (grupo ventilação ciclada à pressão), GPP (grupo ventilação ciclada à pressão com PEEP) e GE (grupo ventilação espontânea - grupo controle). Os animais foram anestesiados com isoflurano, em circuito com reinalação de gases, durante duas horas. As médias de pressão arterial média (PAM) e pressão arterial sistólica (PAS) permaneceram discretamente abaixo dos valores normais em todos os grupos. Houve diminuição significativa da PAM e da PAS no grupo submetido à PEEP (GPP) ao longo do tempo. A pressão parcial de dióxido de carbono arterial (PaCO2) foi maior no GPP quando comparado aos outros grupos no último momento, gerando acidemia respiratória após uma hora de procedimento. A concentração de dióxido de carbono ao final da expiração (ETCO2) apresentou médias discretamente elevadas no grupo não tratado com PEEP (GP) e no grupo controle, enquanto o GPP apresentou maiores médias, possivelmente, relacionadas à diminuição do volume corrente neste grupo. Com base nesses resultados, foi possível concluir que a utilização da PEEP levou à acidemia, que se agravou ao longo do tempo anestésico. Ademais, a anestesia prolongada com isoflurano promove depressão cardiorrespiratória, independentemente do modo ventilatório empregado.(AU)

Pressure controlled ventilation with or without positive end-expiratory pressure (PEEP) was compared in rabbits, which were divided into three groups denominated GP (pressure cycled ventilation group), GPP (pressure cycled ventilation with PEEP group) and GE (spontaneous ventilation group - control group). The animals were anesthetized with isoflurane in a gas rebreathing circuit for two hours. The means of mean arterial pressure (MAP) and systolic blood pressure (SBP) remained slightly below normal values ​​in all groups. There was a significant decrease in MAP and SBP in the group submitted to PEEP (GPP) over time. The partial pressure of arterial carbon dioxide (PaCO2) was higher in GPP when compared to the other groups, inducing respiratory acidosis after one hour. The end-expired carbon dioxide concentration (ETCO2) presented slightly elevated means in the GP, while the GPP presented higher means, possibly related to the decrease in tidal volume in this group. Based on these results it was concluded that the use of PEEP led to acidemia that worsened over anesthetic time. In addition, prolonged isoflurane anesthesia promotes cardiorespiratory depression, regardless the ventilatory mode employed.(AU)

Hypotensive and vasorelaxant effects induced by the ethanolic extract of the Mimosa caesalpiniifolia Benth. (Mimosaceae) inflorescences in normotensive rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Caatinga is highly influenced by its seasonality. This species is endemic in the northeastern region, which is rich in plants with pharmacological potential. Many of these plants are used by the population and some of them have confirmed pharmacological properties. Mimosa caesalpiniifolia Benth. (Mimosaceae) is a native plant from northeastern Brazil׳s caatinga, popularly known as sabiá and cascudo. The tea from the inflorescence of this species is used by the population of the semi-arid for the treatment of hypertension, and the utilization of the plant bark for the staunching of bleedings and wound washing in order to prevent inflammation; also, the ingestion of the bark infusion is used in the treatment of bronchitis. However, its pharmacological effects and mechanisms of action have not yet been studied. The aim of the present study was to determine the effect of the ethanolic extract of M. caesalpiniifolia on the cardiovascular system in rats. MATERIAL AND METHODS: In a study for the assessment of the hypotensive effect of the extract, the polyethylene catheters were inserted in the aorta artery and inferior vena cava for the measurement of the arterial pressure and heart rate. When intragastric administration was performed, only one catheter was implanted in the abdominal aorta. In studies for the vasorelaxant activity, mesenteric arterial rings (1-2mm) were used: they were kept in Tyrode׳s solution (95% O2 and 5% CO2) and submitted to tension of 0.75 g/f for 1h. The results were expressed as mean ± S.E.M., significant to the values of p<0.05. RESULTS: The administration of the doses through venous pathway (6.25; 12.5 and 25mg/kg, i.v.) promoted hypotension followed by bradycardia in the higher doses. The pre-treatment with atropine (2mg/kg, i.v.) interrupted both the hypotension and the bradycardia; with hexamethonium, hypotension was reverted and bradycardia was attenuated. While the administration of tea/flowers (25mg/kg i.v.) also promoted a following section of hypotension, a slight increase in heart rate was observed. When administered orally, MC-EtOH/flowers (100mg/kg, v.o.) promoted a decrease in the arterial pressure from 90 min on, without a significant alteration in the heart rate in relation to the control. In the in vitro study, a pharmacological trial was performed with the extracts obtained from parts of the species M. caesalpiifolia (leaves, bark, fruit and inflorescences). Among all extracts tested, the ethanolic extract from the inflorescences (MC-EtOH/flowers) presented higher vasorelaxant potency in relation to the other parts of the plant. Henceforth, MC-EtOH/flowers was used in the sequence. In mesenteric preparations pre-contracted with phenylephrine (10(-5)M), the MC-EtOH/flowers (0.1-750 µg/ml) promoted vasorelaxant effect regardless of the vascular endothelium. MC-EtOH/flowers inhibited the contractions induced by the cumulative addition of phenylephrine (10(-9)-10(-5)mol/l) or CaCl2 (10(-6)-3 × 10(-2)M), in a concentration-dependent way. In contractions induced by S(-)Bay K 8644, a Cav-L activator, the MC-EtOH/flowers promoted concentration-dependent relaxation, corroborating previous results. CONCLUSION: The tea of flowers of M. caesalpiniifolia promotes hypotension and tachycardia, whereas ethanolic extract (MC-EtOH) promotes hypotension and bradycardia involving the participation of the muscarinic and ganglionic pathways, as well as vasorelaxant action involving the Ca(2+) influx inhibition blockade.

An extended model of phosphorus metabolism in growing ruminants.

A major objective of this study was to extend the Vitti-Dias model used to describe P metabolism in ruminants, by adding 2 new pools to the original model to represent the rumen and saliva. An experiment was carried out using 24 male sheep, initial BW of 34.5 kg, aged 8 mo, fed a basal diet supplied with increasing amounts of dicalcium phosphate to provide 0.14, 0.32, 0.49, and 0.65% P in the diet. Sheep were individually housed indoors in metabolic cages and injected with a single dose of 7.4 MBq of (32)P into a jugular vein. Feed intake and total fecal and urinary outputs were recorded and sampled daily for 1 wk, and blood samples were obtained at 5 min, and 1, 2, 4, 6, 24, 48, 72, 96, 120, 144, and 168 h after (32)P injection. Saliva and rumen fluid samples were taken on d 6, 7, and 8. Then, animals were slaughtered and samples from liver, kidney, testicle, muscle, and heart (soft tissue) and bone were collected. Specific radioactivity and inorganic P were then determined in bone, soft tissue, plasma, rumen, saliva, and feces, and used to calculate flows between pools. Increased P intake positively affected total P (r = 0.97, P < 0.01) and endogenous P excretion in feces (r = 0.85, P < 0.01), P flow from plasma to saliva (r = 0.73, P < 0.01), from saliva to rumen (r = 0.73, P < 0.01), and from lower gastrointestinal tract to plasma (r = 0.72, P < 0.01). Urinary P excretion was similar for all treatments (P = 0.35). It was, however, related to plasma P (r = 0.63, P < 0.01) and to net P flow to bone (accretion - resorption; r = -0.64, P < 0.01). Phosphorus intake affected net P flow to soft tissue (P = 0.04) but not net P flow to bone (P = 0.46). Phosphorus mobilized from bone was directed toward soft tissue, as suggested by the correlations between P flow from bone to plasma and net P flow to soft tissue (r = 0.89, P < 0.01), and P flow from plasma to soft tissue and net P flow to bone (r = -0.76, P < 0.01). The lack of effect of dietary P on net P accretion in bone suggests that P demand for bone formation was low and surplus P was partially used by soft tissue. In conclusion, the model resulted in appropriate biological description of P metabolism in sheep and added knowledge of the effects of surplus dietary P on P metabolism. Additionally, the model can be used as a tool to assess feeding strategies aiming to mitigate P excretion into the environment.

Digestibilidade intestinal in vitro da proteína de coprodutos da indústria do biodiesel / Intestinal protein digestibility of by-products from biodiesel industry

Determinou-se a digestibilidade intestinal (DI) da proteína de vários coprodutos do biodiesel nas formas de farelo e torta. Foram avaliados oito coprodutos: tortas e farelos de pinhão manso, nabo forrageiro, tremoço, algodão. Os coprodutos foram incubados no rúmen por 16 horas, e os resíduos não degradados no rúmen submetidos à digestão enzimática com solução de pepsina e pancreatina para a determinação da DI. Ainda, nos resíduos da incubação ruminal, foram determinadas: degradabilidade da matéria seca (DR), proteína degradável no rúmen (PDR) e proteína não degradável no rúmen (PNDR). A digestibilidade intestinal da proteína para os coprodutos do biodiesel variou de 2,4 a 48,6%. Todos os coprodutos avaliados caracterizaram-se como alimentos de alto teor proteico, sendo considerados de alta PDR, e apresentaram baixa digestibilidade intestinal da proteína. A DI da proteína dos coprodutos do biodiesel na forma de torta foi maior em comparação com a dos farelos. A torta e o farelo de algodão apresentaram os maiores coeficientes de DI.

The objective of this research was to determine intestinal protein digestibility (ID) of some biodiesel by-products in the form of cakes and the meals. Eight by-products were: cakes and meals of physic nut, turnip, lupine, cotton cake, cottonseed meal. The by-products were incubated in the rumen for 16 hours, were the undegradable rumen residues were submitted to enzymatic digestion with pepsin and pancreatin solution for the determination of ID. In the incubation residues the following was also determined: dry matter degradability (RD), rumen degradable protein (RDP) and rumen undegradable protein (RUP). The intestinal protein digestibility of biodiesel by-products ranged from 2.4 to 48.6%. All the by-products evaluated in this study were characterized as high protein sources and were considered high-RDP. The by-products presented low intestinal protein digestibility. The ID protein of biodiesel by-products was higher in the cakes than the meals. The by-products evaluated, the cottonseed cake and meal presented the highest ID coefficients.

Modelos matemáticos no estudo do fluxo biológico de fósforo em ovinos que receberam na dieta níveis crescentes do mineral / Mathematical models to study the biological phosphorus flow in sheep fed increasing levels of mineral

Dois modelos compartimentais foram aplicados e comparados para avaliar o fluxo biológico de fósforo em ovinos que receberam dietas com níveis crescentes do mineral - 0, 2, 4 e 6g por dia. Foram utilizados 24 machos, da raça Santa Inês, com média de peso de 33,6kg. Foi utilizado fosfato bicálcico como fonte de fósforo e 32P como traçador. Avaliou-se o fluxo de fósforo entre os compartimentos: trato gastrintestinal, sangue, ossos e tecidos moles, além da ingestão, excreção e balanço do mineral. O incremento na ingestão de P aumentou a perda fecal do mineral. O fluxo de fósforo entre o trato gastrintestinal e o sangue e o fluxo contrário foram influenciados de forma quadrática pelo incremento na ingestão, diminuindo após a ingestão de 5,5g/dia, sem diferença entre os modelos avaliados. Os modelos estudados mostraram diferenças em relação ao fluxo entre sangue, ossos e tecidos moles, sem efeito dos tratamentos sobre o balanço geral do mineral, porém os níveis de ingestão praticados interferiram no fluxo biológico do fósforo. A disponibilidade biológica do fósforo ingerido diminuiu quando a ingestão superou a necessidade do animal, o que aumentou as excreções no ambiente. A quantificação do fluxo biológico de fósforo diferiu quando aplicados os modelos estudados em decorrência da sua estrutura.

Two compartimental models were applied and compared to evaluate the biological flow of P in lambs fed diets containing increasing levels of P (0, 2, 4 and 6g per day). Twenty four Santa Inês lambs with liveweight of 33.6kg were used. Dicalcium phosphate was used as P source and 32P as a tracer. P flow between compartments (gastrointestinal tract, blood, bones and soft tissues), ingestion, excretion and the mineral balance were evaluated. The increase in P intake increased fecal P loss. P flow from gastrointestinal tract to blood stream and opposite flow were affected quadratically by increased P intake, decreasing after the ingestion of 5.5g/day, without a difference among models. The models studied showed differences regarding the P flow between blood, bone and soft tissues, however, the P balance was not affected by the treatments. The increased P levels interfered with the biological P flow in sheep. The bioavailability of P diet decreases when intake exceeds the animal requirement, increasing losses to the environment. The quantification of biological P flow was different between models due to the structure of each one.

Fluxo do fósforo de diferentes fontes de fosfatos em bovinos / Phosphorus flow from different phosphate sources in cattle

Objetivou-se estudar o fluxo do fósforo (P) de diferentes fontes de fosfatos, em bovinos. Para avaliaçäo matemática das trocas de P entre os compartimentos fisiológicos ou antômicos foi usado um modelo dividido em trato digestivo, sangue e ossos mais tecidos moles. Concluiu-se que o P do fosfato bicálcico é melhor absorvido pelos bovinos do que o dos fosfatos Patos de Minas e Tapira. As fontes de P, fosfatos bicálcico, Patos de Minas e Tapira, näo interferiram na incorporaçäo de P no osso e tecidos moles e o fluxo de P do trato digestivo para o sangue e deste para o trato digestivo, em bovinos, aumentaram com a absorçäo desse mineral