The kinetics of uptake of 5-fluorouracil by rat liver

1 Slices of rat liver weighing 15-30 mg were incubated at 37 degrees C in 5-fluorourecil (5-FU) solution. 2 The 5-FU taken up was measured by high pressure liquid chromatography. 3 Uptake of 5-FU was found to approximate to Michaelis-Menton kinetics with the values of Kt and Vmax equal to 15.39 mmol 1-1 and 1.96 mumol g-1 min-1 respectively. 4 Transport of 5-FU was saturable with the uptake being much greater in the non-fasting rats. 5 Intracellular concentration of 5-FU after 24 min incubation approached but did not significantly exceed that in the extracellular fluid. 6 Enzymatic destruction of 5-FU at 2 min was negligible but substantial after a long incubation period. 7 2,4-Dinitrophenol was found to inhibit transport of 5-FU significantly. 8 Results suggested that the mechanism of uptake of 5-FU by rat liver is an energy requiring process.

A rapid method for screening urine samples in suspected abuse of cocaine

We report a quick method for the detection of cocaine and its major metabolites by thin-layer chromatography with confirmation by gas-liquid chromatography. Because it is possible to use the same chloroform-isopropanol extracts of urine in both procedures, the method is convenient for screening large numbers of urine samples.

Determination of 5-fluorouracil in human plasma by high-pressure ion-exchange chromatography

A method has been developed for the measurement of 5-fluorouracil by isocratic high-pressure ion-exchange liquid chromatography. Chlorpheniramine was added to the standards and samples before extraction with 16% isopropanol in ethyl acetate. The extracts were then chromatographed using a mobile phase of 0.014 mol/l ammonium dihydrogen phosphate buffer, pH 3.5, at a flow rate of 1 ml/min. Ultraviolet detection at 266 nm was used, and quantitation was by measurement of the peak height ratios of 5-fluorouracil to chlorpheniramine.

Volume changes induced in rabbit polymorphonuclear leukocytes by chemotactic factor and cytochalasin B

Incubation of rabbit neutrophils with various chemotactic factors causes an expansion of their volume. The expansion shows a high correlation with the chemotactic responsiveness of these cells, requires metabolic energy, and is independent of the presence of divalent cations. Cytochalasin B causes a decrease in the volume of the neutrophil. This decrease also requires metabolic energy and is independent of divalent cations. In the presence of cytochalasin B, the chemotactic factor, instead of acting to expand cell volume, induces a further contraction of the cell; this decrease requires Ca2+ in the external medium.