[Activation of the bioluminescence of the sensor Escherichia coli strains used for detecting N-acyl-homoserine lactones in the presence of nitrofurans and NO generators].

Nitrofurans (nitrofurazone, nitrofurantoin, furazidin, nifuroxazide), and nitric oxide generators (sodium nitroprusside and isosorbide mononitrate) in subinhibitory concentrations were shown to significantly increase the bioluminescence of the sensor Escherichia coli strains used for detecting N-acyl-homoserine lactones, signaling molecules of Quorum Sensing (QS) regulatory systems. The highest activation of bioluminescence (up to 250-400 fold) was observed in the presence of nitrofurazone on E. coli DH5alpha biosensors containing lux-reporter plasmids pSB401 or pSB536. However, this activation was not specifically associated with the functioning of QS systems. We suggest that the effect observed results from a direct action of nitrofurans and NO donors on the process of bioluminescence. The data indicate the necessity of using the biosensors that make it possible to detect specific effects of substances tested on QS regulation.

[Antiulcer activity of furoxanopyrimidine derivatives]. / Protivoiazvennoe deistvie proizvodnykh furoksapirimidina.

A series of four new furoxanopyrimidine derivatives was synthesized and studied with respect to antiulcerous, antisecretory, and antibacterial activity. Two compounds exhibit antiulcerous effect not accompanied (in contrast to the well-known H2 receptor blockers, quiditene, and other antiulcerous drugs) by inhibition of gastric acid secretion. No one of the studied compounds exhibited antibacterial activity in the tests with Helicobacter pylori.

Derivatives of 1,2-diazetidine-1,2-di-N-oxides--a new class of soluble guanylate cyclase activators with vasodilatory properties.

Derivatives of diazetidine-di-N-oxides have been found capable of the nonenzymatic generation of nitric oxide by the principally new mechanism of the nitric oxide splitting at physiological pH values. The effect of the synthesized compounds on human platelet soluble guanylate cyclase activity as well as their spasmolytic and hypotensive action were studied. Four of 7 derivatives studied exhibited a distinct correlation between the ability of being decomposed with the nitric oxide formation, activation of soluble guanylate cyclase, and spasmolytic and antihypertensive activities. Among them, 3-brom, 4-methyl-3,4-tetramethylene-diazetidine-di-N-oxide has proved to be most effective, its spasmolytic effect being commensurable with glyceryl trinittrate activity. The revealed correlation allows us to regard 1,2-diazetidine-1,2-di-N-oxide derivatives as vasodilatory agents of a new class.

[Distribution of different groups of indirect sympathomimetics between aqueous and "fatty" phases]. / Raspredelenie raznykh grupp nepriamykh simpatominetikov mezhdu vodnoi i "zhirovoi" fazami

Ionization constants were measured and distribution between the "fatty" and aqueous phases of the drugs (amphetamine, ephedrin, tyramine, methylphenidate, pipradrol), belonging to two groups of indirect sympathomimetics differing in the mechanism of their action, was studied. The lipophilic nature of the study compounds is shown to correlate with some pharmacological properties determining the difference in action produced by these drugs.