Correction of immunity disorders, treatment of intestinal infections and disbiosis in children (clinical review)

Acute viral and bacterial intestinal infections in children provoke the Tn2 immune response, resulting in development of severe and complicated forms of the disease and sustained by the disbiotic disturbances due to unnecessarily prolonged use of antibacterial drugs. Cycloferon, an early inductor of interferon-1 and -2, was shown to be safe and efficient in the complex therapy of the intestinal infections. It promoted generation of the Th2 immune response and decrease of the repeated isolation of the pathogen with normalization of the disease clinical signs. The host intestinal microflora was normalized and the level of the opportunistic organisms decreased.     

Ultrathin structure of normally growing and regenerating cells of Acetabularia mediterranea]

The ultrastructure of nucleus and cytoplasm in regenerating cells of Acetabularia mediterranea differs from that in normally growing ones: the nucleus of regenerating cells form numerous outgrowths; the cortical layer of nucleolus disintegrates markedly; the emission of nucleolar material in the nucleoplasm is observed. In the cytoplasm the portion of active chloroplasts increases and a great number of tubular fibrils appears. In the cytoplasm of regenerating cells the Golgi dictyosomes occur more frequently and the vesicles at their ends are larger than in that of normally growing cells. The changes of macromolecular organization of the nucleus and cytoplasm in question observed at the earlier stages of regeneration (2--12 hrs) suggest the increase of metabolic activity of cells.     

Cytomorphological changes in human tumor cells exposed to high-polar compounds

The effects of some high-polar compounds on the cytomorphological characteristics of cultured cells of synovial and osteogenic human sarcomas (Sa-2 and Sa-4) were studied. Incubation of Sa-2 cells with 1 or 2% dimethylsulfoxide (DMSO) or 100 mM dimethylformamide (DMF) during 4-6 days induced the cellular, structural and functional changes in Sa-2 cells which were considered as manifestations of pseudoepithelial differentiation. DMSO did not influence the activity of Sa-2 cell enzymes, while DMF suppressed their activity, mainly that of acid and alkaline phosphatases. DMSO and DMF induced in Sa-4 cultured the appearance of the cells which were similar cytomorphologically to normal osteoblasts. DMSO and DMF significantly depressed the activity of acid phosphatase in Sa-4 cells and transformed the positive reaction of alkaline phosphatase to the negative one. DMSO and DMF prolonged the time of the doubling of Sa-2 and Sa-4 cells. The effects of DMSO and DMF were reversible. Methylformamide (200 mM) and dimethyl acetamide (0,1 and 10 mM) did not induce analogous changes in human sarcoma cells.     

Regularities of the content and organization of pyrimidine oligonucleotide sequences in insect DNA

Certain regularities in content and organization of pyrimidine oligonucleotide sequences of DNA from 15 insect species belonging to 4 orders were studied. The degree of nucleotide clusterization in insect DNA was found to be species-specific, being the highest in Hymenoptera and lowest in Lepidoptera; the Blattodea and Coleoptera occupy an intermediate position by this index between them. The changes in the DNA cluster structure during the evolution of insect species are not of vector type; the degree of clusterization of DNA nucleotide is either increased (Hymenoptera) or decreased (Lepidoptera as compared with Blattodea). In the DNA oligonucleotide fractions containing both pyrimidine nucleotides the percentage content of thymidyl nucleotides is much higher than that of cytidyl nucleotides, the thymine content being increased with the lengthening of oligopyrimidine clusters. The insect species with a higher degree of clusterization of DNA pyrimidine nucleotides contain more thymidyl nucleotide residues. These results agree well with the hypothesis suggesting that during the evolution of large taxons the accumulation of long pyrimidine sequences in animal DNA is accompanied by an increase of thymidyl nucleotide content in them. This can largely be due to the increase of matrix resistance during the evolution and is biologically significant for animals of any taxons, including insects.     

An analysis of the DNA synthesized in adenovirus-infected cells under exposure to nucleoside analogs

The method of dot DNA-DNA hybridization was used to reveal the inhibition of the synthesis of the adenoviral DNA by 6-azacytidine, cyclocytidine and ribamidyl in the adenovirus-infected cells Hep-2, a degree of which depended on the preparation concentration.     

X-ray-induced breaks in the X chromosomes in Drosophila lines of various radiosensitivities

The frequency of X-ray induced X-chromosome breaks has been studied in females of the line rad (2) 201G1 hypersensitive to radiation and in females of the control line selected from the same population. The frequency of X-chromosome breaks was judged based on the frequency of X0 males occurrence. Synergism of the effects of X-rays (at doses 0.1, 0.5 and 1.0 kr) and of hyperthermia (+37 degrees C, 5.5 hours) applied after irradiation served as an indirect evidence for the functioning of DNA repair systems. It is demonstrated that radiosensitivity of mature oocytes of the lines compared was equal and that hyperthermia applied after irradiation increased the latter effect in both lines. Young oocytes of the control line were radioresistant, and hyperthermia applied after irradiation enhanced its effect. Opposite to them, young oocytes of the rad line females were radiosensitive. They did not differ from mature oocytes in the frequency of X-chromosome losses. Synergism of the two factors (irradiation and hyperthermia) was not registered in young oocytes. On the basis of the results obtained, it may be concluded that radiosensitivity of young oocytes in the hypersensitive line is conditioned by the failure of DNA repair systems and that the rad (2) 201G1 gene may be considered, in relation to the genes controlling DNA repair, as a suppressor functioning selectively at a certain stage of oogenesis.     

Radiobiological method of studying the structure of the partially diploid area in T4 bacteriophage]

The mechanism of cross-reactivation after UV-irradiation was examined using different deletion mutants as recipients. A model of the rescue mechanism of partly diploid area was suggested. The method of cross-reactivation in demonstrated to permit an easy determination of the orientation of duplicated genes.