Thin-layer chromatography of 1,2,4-triazoles on silica gel

Summary The TLC behaviour of N-phenyl-1,2,4-triazoles and their derivatives on silica gel plates has been studied using simple solvents. Isomers were very well distinguished, resulting from different activities due to hydrogen bonding. A mixture of seven compounds has been resolved with diethylether-n-butylamine-pyridine (91.4:7.7:0.9).     

Thin-layer chromatography of steroids on microplates with fixed silica gel

Summary 1. A method for chromatographing steroids on microplates with silica gel of types KSK and KSM has been developed.2. The possibility of using a solution of iodine in potassium iodide to detect steroid compounds has been demonstrated and the sensitivity of this reaction has been determined.Khimiya Prirodnykh Soedinenii, Vol. 2, No. 5, pp. 321–325, 1966     

Rapid automated high-performance liquid chromatographic analysis of cyclic adenosine 3',5'-monophosphate. Synthesis in brain tissues

A rapid and sensitive automated system for measuring cyclic adenosine 3',5'-monophosphate (cAMP) synthesized from either radiolabelled adenine or adenosine 5'-triphosphate (ATP) in intact and broken cell tissue preparations, respectively, is described. After incubation with radiolabelled precursor, tissue samples are deproteinized and then injected directly onto a reversed-phase high-performance liquid chromatographic column. The column effluent fraction which contains cAMP is collected into scintillation vials and assayed for tritium by liquid scintillation spectrometry. Since the high-performance liquid chromatographic and fraction collection procedures are automated, over fifty samples can be analyzed in duplicate in a single day. The utility of this assay is illustrated by investigations of the effects of beta-adrenergic receptor stimulation on cAMP synthesis in tissue slices prepared from rat cerebral cortex and dopamine on cAMP synthesis in striatal membrane preparations.     

Thin-layer chromatography of sulphonamides on silica gel G and polyamide layers by means of a polar mobile phase.

A thin-layer chromatographic system based on polyamide or silica gel G layers and an aqueous mobile phase was used for the separation of a series of sulphonamides. A linear relationship between RM values on polyamide layers and the acetone concentration in the mobile phase allowed the calculation of extrapolated RM values. The influence of the nature of the stationary phase on the migration of compounds is discussed.     

Elevation of intracellular cyclic adenosine 3',5'-monophosphate levels in macrophages activated with lipopolysaccharide for tumor cell killing.

The macrophage activation for tumor cytotoxicity with lipopolysaccharide (LPS) was remarkably inhibited by adding indomethacin (5 x 10(-6) M) or 10mM LiCl which is known to inhibit adenylate cyclase activity. The tumor cytotoxicity of macrophages inhibited with these agents was recovered by adding dibutyryl cyclic adenosine 3',5'-monophosphate (cAMP) (10(-4) or 10(-5) M) and furthermore tumor cell killing activity was augmented as compared with LPS-activated macrophage. Macrophages showed a 5 to 6 times increased intracellular cAMP concentration over the control within 30 min when incubated with LPS. However, the increased intracellular cAMP concentration was decreased by adding LiCl (10 mM). Thus, these findings indicate that there is an important relation between intracellular cAMP concentration and the mechanism of macrophage activation. One can then conclude that at least the initial enhancement of intracellular cAMP was important for tumor cell killing as a signal transmission in macrophage activated by LPS.