Pharmacokinetics of plasmatic plasminogen activator in rabbits

The pharmacokinetic characteristics of APP were studied in 10 male New Zealand rabbits. An initial dose of 15,000 IU of APP per kg of weight was administered. The respective fibrinolytic activity was estimated by fibrin plates and transformed according to theoretical considerations. Knorre's criterion was used for the determination of the number of compartments. In every case the values were below 0.2 which indicates a one-compartment open model. The data were fitted to the proposed model in two steps; first the stripping method was used, afterwards the values obtained by the stripping were used as initial values for nonlinear fitting by means of nonlin programs.     

Intralipid and free plasmatic tryptophan in vitro

In an attempt to investigate the role of the lipidic emulsion Intralipid in the development of metabolic encephalopathy in a patient showing high free tryptophan levels, the relationship between lipidic emulsion and free tryptophan was examined in in vitro experiments. The addition of intralipid to normal serum produces an immediate increase in non-esterified fatty acids and a parallel rise in free tryptophan. Moreover, when serum with intralipid is incubated at 37 degrees C, the lipases release new non-esterified fatty acids and the free tryptophan increases proportionally. The non-esterified fatty acid content of intralipid was found to be 12 +/- 2 mEq X 1(-1). An inverse correlation was seen between free tryptophan and different serum albumin concentrations. It is concluded that intralipid causes an increase in free tryptophan levels. It is known that in vivo free tryptophan modulates 5-hydroxytryptamine synthesis and thus may be considered a possible causal agent for encephalopathy.     

Isolation of skeletal muscle plasmatic membranes as closed vesicles

Ultrasonic treatment of skeletal muscle sarcolemma preparations in 0.25 M sucrose, 0.1 M NaCl, 0.001 M tris-HCl-buffer (pH 7.4) induces formation of closed osmotically active vesicles which may be isolated by centrifugation of a sonicated suspension within the sucrose density gradient. The vesicles retain the enzymic activity peculiar to the initial sarcolemma preparations.