[Ishemic-reperfusion syndrome prophylaxis in general hypothermia in experiment].

The influence of general supercooling on rats were studied. The action of corvitin and pentoxiphillin on the prooxidant-antioxidant homeostasis for conditions of general supercooling were analysed. On the based of investigations results analysis of lipids peroxide oxidation indexes and antioxidant protection system in animals it were established, that corvitin in difference of pentoxiphillin give more significant protectory effect in conditions of ishemic-reperfusion syndrome.

[Neuroprotective effect of quercetin during experimental brain ischemia].

The neuroprotective action by water-soluble form of quercetin was examined in gerbils after transient forebrain ischemia. The animals were exposed to 7 min of bilateral common carotid artery occlusion. Hippocampal CA 1 area was examined 7 days after ischemia-reperfusion. The average density of CA1 pyramidal neurons and GFAP-positive glial cells were counted in sham operated group, in ischemic group and in the groups treated with water-soluble form of quercetin. It was shown that quercetin revealed protective effect by decreasing of delayed neuronal death and reducing reactive astrogliosis after ischemia-reperfusion.

Antisignature oligonucleotides and their analogs as inhibitors of mollicutes-cofactors of HIV.

Inhibition of mollicutes by synthetic oligonucleotides and their analogs complementary to specific "signature" regions of 16S rRNA and corresponding sequences of ribosomal operon DNA was studied. It was shown that antisignature oligonucleotides inhibited transcription in vitro for above 79% interacting specifically with ribosomal operon and non-specific with DNA-dependent RNA-polymerase. The inhibition efficiency depended on oligonucleotide sequence and type of modification. Translation in vitro was suppressed most efficiently (up to 60%) by oligonucleotides complementary to 3'-end region of 16S rRNA, also depending on their modification. Translation in vivo was inhibited most efficiently (up to 73%) by thiophosphate analogs of oligonucleotides complementary to sequences 499-507 and 523-532 of 16S rRNA responsible for binding of ribosomal "core" protein S4 starting the assembly of 30S ribosome subunit. With the simultaneous use of the last two oligonucleotides, the growth of mollicutes in SM IMV-72 medium rich in exogenous sources of nucleosides was suppressed for over 90%. It is supposed that under conditions where mollicutes have no free access to starting materials for their own synthesis of nucleic acid these nucleotides could suppress microorganisms completely. Antisignature oligonucleotides are considered as superspecific agents not leading to the development of resistance of mollicutes and believed to be the main future remedy against diseased caused by microorganisms lacking the system of nucleoside synthesis.

[The validation of the possible use of monosugars and 6-azacytidine for the elimination of Mollicutes associated with HIV/AIDS from the human urogenital tract]. / Obhruntuvannia mozhlyvosti zastosuvannia monotsukriv i 6-azatsytydynu dlia eliminatsiï z urohenital'noho traktu liudyny molikutiv, iaki asotsiiuiut' z VIL/SNIDom.

A search for the methods new in principle which should block and eliminate AIDS-associated mycoplasmas was carried out. This work was conducted in two ways: 1) inhibition of vital activity of Mycoplasma fermentans PG-18 and Acholeplasma laidlawii PG-8 by 6-azacytidine; 2) establishment of carbohydrate composition of receptors for these mycoplasmas aimed at the competitive elimination of these microorganisms from urogenital tract of a man using carbohydrates. It is established that a 50%-inhibiting concentration of 6-azacytidine was 23.4 micrograms/ml for M. fermentans PG-18 and 62.5 micrograms/ml for A. laidlawii PG-8. alpha-D-glucose and N-acetylneuramine acid are two terminal carbohydrates that can serve as receptors for M. fermentans on human mucous membranes while D-mannose and N-acetyl-D-glucosamine for A. laidlawii PG-8. alpha-D-glucose in concentration 75 mM and N-acetylneuramine acid in concentration 150 mM competitively inhibit reception of M. fermentans on mucosae, while D-mannose in concentration 150 mM and N-acetyl-D-glucosamine in concentration 75 mM are antireceptor substances for A. laidlawii.

[The ability of the oligodeoxyribonucleotides complementary to the 3'-terminal segment of 16s-rRNA in Mollicutes to suppress translation in their ribosomes in an in-vitro system]. / Sposobnost' oligodezoksiribonukleotidov, komplementarnykh 3'-kontsevomu uchastku 16S-rRNA mollikutov, podavliat' transliatsiiu na ikh ribosomakh v sisteme in vitro]

Effect of oligodesoxyribonucleotide, complementary to 3'-end sequence (3'-UCUUUCCUCCAC) of 16S-rRNA of mollicutes, and its phenasine derivatives on the process of translation of mollicute has been studied in the system of in vitro translation, created on the basis of ribosomes of Acholeplasma laidlawii var. granulum str. 118 and germ extracts of the wheat and optimized in respect of the temperature (23 degrees C), translation time (70 min), concentration of potassium and magnesium ions (150 and 5 mM, respectively). It is shown that acholeplasma ribosomes are most efficiently inhibited (60%) under their interaction with oligonucleotide containing one phenasine insert on the 3'-end, nonmodified oligonucleotide exerted a bit less inhibiting effect (58%). Oligonucleotide containing intercalating inserts in 3'- and 5'-positions manifested the least inhibiting effect (35%). It is noted that the efficiency translation inhibition by synthetic oligonucleotides is conditioned by nuclease activity of the system and by the length of the section of active binding of oligonucleotide with the sequence target on rRNA. It is supposed that oligonucleotides complementary to certain unique rRNA sequences can become promising highly specific drugs for prophylaxis and treatment of mycoplasmoses.

[Oligodeoxyribonucleotides complementary to sections of the mollicute ribosomal operon as transcription inhibitors in vitro]. / Oligodezoksiribonukleotidy, komplementarnye uchastkam ribosomal'nogo operona mollikutov, kak ingibitory transkriptsii in vitro.

Antisense oligodeoxyribonucleotides have been studied for their effect on the transcription in vitro in mollicutes. A synthetic fragment of DNA [symbol: see text] complementary to that part of DNA which codes the 1510-1521 area of the 3'-terminal sequence 16S-pRNA of all mollicutes was used in the study as well as its modifications by imidasophenasine derivatives: [symbol: see text], [symbol: see text] [symbol: see text]. Maximal inhibition of the mollicute transcription in vitro was observed with 100 nM oligonucleotide concentration. Lower or higher concentrations were less effective. Transcription initiated by RNA-polymerase of M. fermentans PG-18 (a mollicute strain referring to AIDS disease) proved to be the most sensitive to the effect of modified oligonucleotide: it was inhibited by 75-80%. It is concluded that modified oligonucleotides exert a dual effect on transcription: firstly, they participate in nonspecific interaction with RNA-polymerase which induces insignificant inhibition of transcription and, secondly, they complementary interact with homologous sections of one-stranded DNA-matrix and block the RNA synthesis. Binding of modified oligonucleotides with DNA is rather strong.

[The inhibitory action of 6-azacytidine on Mollicutes and its proposed mechanism]. / Ingibitornoe deistvie 6-azatsitidina na mollikuty i ego predpolagaemyi mekhanizm.

6-Azacytidine (6-AC) is shown to have an inhibitory effect on the Mollicutes of the different systematic position. The growth of type strains of Mollicutes (Acholeplasma laidlawii PG-8, Mycoplasma pneumoniae FH and M. fermentans PG-18) completely ceased in the nutrient medium at concentration of the above substance in it within the range of 125-250 micrograms/ml. 50% inhibiting concentration of 6-AC equaled: for M. fermentans PG-8: 23.43 micrograms/ml; M. pneumoniae FN: 46.8 micrograms/ml; Acholeplasma laidlawii PG-8: 62.5 micrograms/ml. 6-AC concentration 5 micrograms/ml decreased the process of DNA-dependent DNA synthesis in the in vitro system more than by 60%. 6-AC exerted less effect on the DNA-dependent RNA synthesis in the in vitro system: at different concentrations of 6-AC (up to 400 micrograms/ml) RNA synthesis decreased only by 20%. Translation on ribosomes of Mollicutes in the in vitro system completely ceased at 6-AC concentration 100 micrograms/ml. The results obtained indicate that for 6-AC in cells of Mollicutes and, possibly, for other microorganisms there are two targets: ribosomes and DNA-dependent DNA-polymerase. Total effect of blocking of the translation and replication processes by 6-azacytidine causes death of Mollicutes. Since 6-AC has no harmful effect on the human cells, it can be used as an efficient method for treatment of respiratory and urogenital diseases induced by Mollicutes.