Ultrastructure of mesenteric lymphatic postcapillaries of the small intestine of the human fetus

Lymphatic vessels of the small intestine mesentery have been investigated in 36 human fetuses 3-6-month-old. Lymphatic postcapillaries are the predominant link in the lymphomicrocirculatory bed studied. They differ from the capillaries only by presence of valves. Intersegmentary valves and velves at the places where the lymphatic capillaries get into the postcapillaries are described; they are situated along the whole length of the postcapillary. Both types of the valves can be uni- and besinusoid, and according to the number of endotheliocytes, covering the sinuses, uni- and multicellular. Cells of fibroblastic line and developing collagenous fibers are inevitable structural components and situate in their base. Ultrastructural peculiarities of the lymphatic postcapillary wall are described. Structural mechanisms responsible for dilatation and narrowing of the vascular lumen (formation of the pulse wave) are discussed. The data obtained support the conception successively elaborated by V. V. Kuprianov on the lymphatic postcapillary as an inevitable link of the lymphomicrocirculatory bed.     

Capacitive and ionic currents in BLM from phosphatidic acid in Ca2+-induced phase transition

The development of electric current with time in a bilayer lipid membrane (BLM) formed from dipalmitoylphosphatidic acid on introducing Ca2+ ions into the medium was studied at constant temperature and pH. The phase transition in the Ca2+-induced BLM is accompanied by the initial capacitive current followed by the occurrence of single ionic channels. The amount of transported charges in the capacitive current is 5 C/ microF. The conductivity of the single ionic channels ranges from 50 to 100 pSm.     

Behavioral specialization of cortical and hypothalamic neurons in the rabbit

Behavioural specialization was analyzed of hypothalamic and limbic neurones, with their activity recorded in rabbits during food-acquisition behaviour. The neurones with activity changed during staying of the animal in a definite place of the cage or during behavioural acts, characteristic of a specific behaviour in the cage, are considered as specialized in relation to the most "new" systems, acquired by the rabbit directly during learning of the given behaviour. Neurones with the activity changed with rabbit's turns, i.e. connected with behavioural acts, which the rabbit has not specially learnt, are considered specialized in relation to more "old" inborn systems. Neurones, in which no constant connection with any part of the studied behaviour was observed, are related to the most "ancient" systems. Comparison of the number of hypothalamic and limbic neurones of different groups showed that in the cortex there were some more neurones specialized in relation to behavioural acts, which were formed directly during learning of the rabbit in the experimental cage.     

Cloning of the Bacillus subtilis DNA fragment containing the genes for lysine and riboflavin biosynthesis

The SalI fragment of chromosomal DNA of Bacillus subtilis carrying the gene for lysine biosynthesis and the regulatory operator region (ribO) from the riboflavin gene was cloned into Escherichia coli cells. This fragment was shown to contain the gene coding for lysine synthesizing enzyme. Localization of this gene in Bac. subtili was determined. New plasmids pLRS33 and pLRB4 were constructed using pBR322; they carry a fragment homologous to pLP102 plasmid containing the operon for riboflavin biosynthesis.     

Patterns in the development of the ultrastructure of elements of the microcirculatory system in the early stages of human embryogenesis

By means of transmissive electron microscopy methods, general regularities in development of the microcirculatory system have been studied at early stages of the human prenatal ontogenesis in functionally different organs. Ultrastructure of two cell types has been described in the mesenchyme of human embryos. Formation mechanisms of the primary blood vessels belonging to the protocapillary type are revealed. Structural peculiarities of the primary protocapillary network differentiating into various links of the secondary organospecific hemomicrocirculatory bed are distinguished. Certain stageness in development of the microcirculatory system is stated, its blood circulatory compartment including. Two stages are determined in development of the microcirculatory system: prevascular and vascular microcirculation. The latter includes the precirculatory and circulatory phases.     

The cytogenetic effect of chronic irradiation revealed using an analysis of the first two mitoses in the root meristem of germinating seeds of Crepis tectorum from the 30-kilometer zone of the accident at the Chernobyl Nuclear Power Station

Peculiarities of the appearance of C. tectorum rootlet in the course of seed germination have prompted the authors to use the method of continuous germination of seeds in 0.01% colchicine solution and to analyze chromosome aberrations in the first tetraploid cells derived from early dividing cells. Since it has been shown that cells of the embryo's root meristem of dormant Crepis tectorum seeds are at the G1 stage, the observed, by the method used, chromatid aberrations in the cells that early enter mitosis, are probably induced by the incorporated radioactive products at stages S and (or) G2 during seed germination.     

The synthesis of <Emphasis Type="Italic">O</Emphasis>-substituted 3-oximes of 6α -methyl-16α,17α-cyclohexanopregn-4-ene-3,20-diones tritium-labeled in the 1,2-position

1,2-Tritium-labeled 3-(O-carboxypropyl)- and 3-(O-carbomethoxypropyl)-oximes of 6α-methyl-16α,17α-cyclohexanopregn-4-ene-3,20-diones were obtained by the homogeneous catalytic hydrogenation of 1,2-dehydroprecursors with gaseous tritium and the subsequent separation of the resulting mixtures by HPLC. The specific radioactivities of 50–55 Ci/mmol were prepared using tris-(triphenylphosphine)-rhodium chloride.     

Immunostimulating and anticoagulating activity of fucoidan from brown algae Fucus evanescens of Okhotskoe sea]

Fucoidan--nontoxic sulfated polysaccharide was isolated from brown algae Fucus evanescens in Okhotskoe Sea. Chemical analysis of the compound was performed, it was shown that fucoidan is freely soluble in water and acid solutions. Immunotropic and anticoagulating properties of the compound were evaluated in comparison with heparin. It was demonstrated that fucoidan in wide range of doses stimulated phagocytic and bactericidic activity at leucocytes of mice peritoneal exudate. Heparin on the contrary demonstrated depressive effect on these functions at high dose. It was shown that fucoidan has dose-dependent anticoagulating activity in vitro and in vivo comparable with heparin activity. The results of investigation demonstrated possibility of fucoidan application as immunomodulating and anticoagulating agent of plant origin.