Refractive index and thickness of the outer layer of particles of dispersed perfluorochemical-based blood substitutes

A calculation of the refractive index of particles of a disperse perfluorochemical-based (PFC-based) blood substitute has been made taking into account particular features of the structure of PFC emulsion particles and the equations earlier obtained by one of the authors in the studies on light interaction with optically inhomogeneous 2- and 3-layer spheres. The possibility of averaging by volume the refractive index of 2-layer emulsion particles has been shown. The refractive index of PFC particles has been experimentally determined using independent optical methods, and the thickness of the particle shell formed by a surfactant has been evaluated.     

Effect of MEA on the accumulation of DNA breaks in Bac. stearothermophilus irradiated with gamma and ultraviolet rays and treated with nitrosomethylurea

beta-Mercaptoethylamine (MEA) decreased the accumulation of enzymatic single- and double-strand breaks in DNA of thermophilic bacteria exposed to gamma- and UV-radiation and treated with N-nitroso-N-methylurea. The protective effect of MEA, as registered according to accumulation of single-strand and double-strand breaks in DNA of Bac. stearothermophilus immediately after irradiation and after 30 min postirradiation incubation, was similar.     

Blood vessels in different systems of limb traction (experimental study)

In the experiments performed in 108 dogs, structure of the vascular bed, elongated by means of Ilizarov's apparatus in the extremity pelvic segment, has been studied, as well as the hemostatic system under various regimens of distraction. Under a spare regimen reorientation of the microcirculatory bed links and its neural apparatus according to the lines of tension and distension forces are revealed, as well as new formation and growth of capillaries, nerve fibers and terminals. In the vessels of the muscular type, at the level of the osseous regenerate, the following changes are described: distractive rearrangement and intercalated growth (such as activation of biosynthetic processes in endothelium, adventitium and smooth muscle (SMC) cells), intensive proliferation and longitudinal reorientation of the activated SMC in the middle tunic, in the larger arteries a powerful longitudinal muscular layer is formed between the endothelium and the internal elastic membrane. The tendency for hypercoagulation, that exists at that time, is compensated by antithrombogenic and fibrinolitic blood activity. Under an elevated rate of the distraction or under an unstable fixation of the bone fragments in the apparatus, hypercoagulation is not compensated till the end of the experiment, and in the vessels, simultaneously with the distractive rearrangement, thrombosis, recalibration and obliteration are observed. The data observed and those of the literature, demonstrate that vascular adaptation to a dosed distraction is performed by means of certain rearrangements in the walls and of intercalated growth influenced by the effect of the distension forces. These phenomenon make the base of the mechanisms developing in the organism during its evolution and ontogenesis.     

Effect of mercaptoethylamine on DNA degradation in thermophilic bacteria Bac. stearothermophilus exposed toγ-, UV-radiation or methyluitrosourea

Summary The effect of mercaptoethylamine (MEA) on degradation of DNA in thermophilic bacteria Bac. stear. exposed to-, UV-rays or methylnitrosourea (MNU) was studied. Using centrifugation on alkaline and neutral sucrose gradients, it was shown that MEA inhibits the accumulation of breaks in the DNA of Bac. stear. It also lowers the level of DNA degradation in toluene-treated cells of Bac. stear. under the action of the intrinsic nuclease, reduces the activity of the endonuclease specific for apurinic DNA, as well as that of S₁-nuclease and DNase-I in vitro. The inhibition in the accumulation of DNA breaks is assumed to be due to a decrease of the endonuclease activity in the cells of thermophilic bacteria.     

Purification and characterization of two transcribed repetitive DNA fractions from the pigeon genome

Two fractions of the repeats belonging to intermediate frequency repetitive DNA were isolated from the total pigeon nuclear DNA fragmented to about 450 nucleotides. One fraction was designated as rare repeats (repetition frequency about 35 per haploid genome) and another termed as moderate repeats (repetition frequency about 2500 per haploid genome). The rare repeats, which constitute about 7% of the total DNA, include at least 75% of the repetitive DNA sequences transcribed into the high molecular fraction (>45S) of HnRNA in erythroid cells. These repeats have properties compatible with the characteristics of the class of low frequency interspersed DNA found in genomes of many other Metazoan species. The moderate repeats contribute only about 10–20% of the total repetitive DNA copies present in >45S HnRNA and differ from the rare repeats in some other properties. — The possible role of the rare repeats in the genome is discussed.     

Active immunization to exogenous and endogenous antidepressants. The formation of antibodies to biogenic amines and peptide regulators

The active immunization of rabbits and white rats to antidepressant sydnophen results in the formation of antibodies binding norepinephrine, dophamine, serotonine as well peptide regulatory compounds: substance P, pynorphine, vasopressin and beta-endorphin. The immunization against endogenic antidepressant thyroliberin induces the formation of antibodies to the same biogenic amines and to the gamma-aminobutyric acid, oxytocin and leu encephalin. The data obtained are discussed in connection with some physiological and biochemical changes found earlier during immunization to antidepressants.