RESUMO
In assay of serum proteins by use of the biuret reaction, dextran can cause turbidity by formation of an insoluble complex of dextran with copper and tartrate (or EDTA) in strongly alkaline solution. Whether or not the turbidity occurs depends on the tartrate concentration: turbidity is maximal at about 10 g/L, absent at 20 g/L or more, and only slight and delayed at 4 g/L. Two biuret reagents, containing respectively 5.6 and 22.5 g of tartrate per liter, obviate the interference, but the former is suitable only when a short (5 min) incubation is used. Both reagents show linear calibration curves and yield virtually identical results.
Assuntos
Reação de Biureto/métodos , Proteínas Sanguíneas/análise , Técnicas de Química Analítica/métodos , Dextranos , Cobre , Reações Falso-Positivas , Humanos , Tartaratos , Fatores de TempoRESUMO
An attempt was made to reduce heat loss in elderly patients undergoing major abdominal surgery. Two groups were studied. In one group, efforts were made to minimize heat loss by using a hot-water humidifier in the anaesthetic circuit, a hot-water circulating mattress under the patient and warming all i.v. fluids. Otherwise, the surgical and anaesthetic techniques were comparable. The same anaesthetic technique of nitrous oxide, oxygen, pancuronium and fentanyl with intermittent positive pressure ventilation was used in all cases. Nitrogen loss was measured in urine collected over 48 h from an indwelling urinary catheter inserted soon after induction of anaesthesia. Prevention of heat loss during anaesthesia and postoperative recovery caused a significant reduction in nitrogen loss.