The effect of docosahexaenoic acid moiety on the cytotoxic activity of 1,2,4-thiadiazole derivatives

Among 3-(2-aminopropyl)-1,2,4-thiadiazole derivatives containing substitutable secondary amino group and exhibiting cytotoxic activity towards rat C6 glioma cells three compounds with LD₅₀ values ranged from 6 to 48 μM have been chosen. For these compounds amides with docosahexaenoic acid were synthesized and their cytotoxic activity was studied. It was shown that, although docosahexaenoic acid itself was not toxic for C6 glioma cells, its addition to the amino derivatives of 1,2,4-thiadiazole increased or decreased their cytotoxicity. These results demonstrate that acylation of cytotoxic compounds with docosahexaenoic acid does not necessarily lead to the increase of their activity and sometimes can inactivate a parent compound. This fact should be taken into consideration because of possibility of biological attachment of docosahexaenoic acid to the amino group of anti-cancer drugs.     

Influence of derivatives of arachidonic and docosohexaenic acids on AMPA receptors in Purkinje neurons and cognitive functions in mice

The effect of derivatives of arachidonic and docosahexaenoic acids on AMPA receptors in Purkinje cells from the rat cerebellum was studied using the patch-clamp electrophysiological method. It was shown that derivatives of arachidonic acid-arachidonoyl dopamine and docosahexaenoic acid-docosahexaenoyl dopamine and ester of docosahexaenoic acid with ethylene glycol in nanomolar concentrations effectively potentiated the ionic currents caused by activation of AMPA receptors of kainic acid. Ester of docosahexaenoic acid with nitroethylene glycol blocked AMPA receptors, and anandamide (ethanolamide of arachidonic acid) was not effective. A behavioral test showed that docosahexaenoyl dopamine in doses of 0.1–20 mg/kg had no effect on the learning and memory abilities of the animals tested.     

Interaction of prostaglandin E1 with human high density lipoproteins

The assembly of cytochrome c oxidase subunits I-III was studied in vitro in isolated rat liver mitochondria pre-labeled with [35S]methionine. Individual subunits were immunoabsorbed with monospecific antibodies. Isolated heme a from rat liver mitochondria, when added to radiolabeled mitochondria, induced assembly of subunit I with subunits II and III. Assembly of these subunits was not observed in mitochondria incubated in the presence of heme b(hemin) or in the absence of heme. Quantitative analysis of immunoabsorbed, radiolabeled subunits suggests that the predominant effect of heme a is on the assembly of subunit I with subunit III.     

1,3-Dinitrates of cyclooxygenase metabolites of endocannabinoid 2-arachidonoylglycerol. Synthesis and properties

The 1,3-Dinitrates of glycerol esters of natural prostaglandins that are the cyclooxygenase metabolites of 2-arachidonoylglycerol, an endogenous ligand of cannabinoid receptors, were synthesized for the first time. Four methods of synthesis of these esters were developed via the activation of a carboxyl group and their chemical and pharmacological properties were investigated. The esters exhibit a more selective pharmacological spectrum of activities in comparison with the corresponding natural prostaglandins: some types of myotropic activity were enhanced, while others were loosened. 1,3-dinitroglycerol esters act as vasodilators, whereas the majority of natural prostaglandins act as vasoconstrictors. The observed changes result from the introduction of an NO-releasing fragment into prostaglandin molecule.     

Interaction of prostaglandins with low-density lipoproteins in human blood

Interaction of prostaglandins (PG) with human plasma low density lipoproteins (LDL) was studied, using fluorescent spectroscopy and photoreactive labeling. It was demonstrated that PGE1 at low concentrations (less than 10(-9) M) induces specific lipid rearrangements on the surface of LDL globules. It was assumed that these rearrangements are brought about by the interaction of PG with apolipoprotein B to form short-living complexes. A possible mechanism and biological significance of the observed phenomenon are discussed.     

Modification of recombinant proteins by covalent polysialation illustrated with the example of human insulin

Methods of selective and nonselective covalent immobilization of genetically engineered proteins on molecules of natural polysialic acid are described by the example of human insulin. Such modification increases insulin lifetime in vivo.     

Prostaglandin fluorides in synthesis of natural prostaglandin derivatives at carboxyl group

Methods of synthesis of prostaglandin fluorides were developed and their properties were investigated. These compounds were shown to be convenient synthetic precursors for obtaining esters and amides of natural prostaglandins and their fluorodeoxy analogues.     

Docosahexaenoyl dopamine in freshwater hydra: Effects on regeneration and metabolic changes

The effects of docosahexaenoyl dopamine and docosahexaenoic acid on the regeneration of hydra gastric and basal fragments are studied. Docosahexaenoyl dopamine induced morphogenetic abnormalities such as single ectopic tentacles in the gastric region and projections in the gastric and basal regions. Docosahexaenoic acid had no effect on the morphogenesis except for a mild slowing of the regeneration rate. Since no hydrolysis of docosahexaenoyl dopamine was detected in hydra extract, it was assumed that the morphogenetic effect could be associated with the dopamine component of this complex.     

Nanocomplexes of recombinant proteins and polysialic acid: Preparation,characteristics, and biological activity

A preparation of nanocomplexes containing recombinant proteins (interferons α2b and β1b, insulin, and human granulocyte colony stimulating factor) and natural polysialic acid (PSA) has been described. The incorporation of protein into the complex changes its electrophoretic mobility. Atomic force microscopy reveals the average size of 23-kD insulin complexes with PSA of 10–20 nm and demonstrates that more than 60% of glycopolymer molecules carry a single protein molecule. Experiments with cultured cells show that cytokines bound to polysialic acid retain their ability to regulate cell proliferation. Insulin bound to PSA has a prolonged hypoglycemic effect in vivo.