Specific features of root aerenchyma formation in Sium latifolium L. (Apiaceae).

Types of aerenchyma formation in adventive roots of wild plant S. latifolium L. are described for the first time. Specific cell divisions and patterns of cell growth in the inner and outer root cortex at the initial stages of aerenchyma formation are highlighted in detail. Destructive processes in cells occurred under aerenchyma formation are considered in the view of known stages of programmed cell death in plants.

[Structural and cytochemical aspects of Brassica rapa embryogenesis under conditions of clinorotation].

The results of study of embryo development in B. rapa plants, as well as the rate and the character of nutrient substances accumulation in their cells under slow horizontal clinorotation and laboratory control are presented. Significant similarity of the peculiarities of embryo differentiation and character of nutrient substance accumulation in both variants was shown. The cases of different deviations during embryo differentiation, and rate and quantity of reserve nutrient substances in their cells are revealed under clinorotation compared to the laboratory control.

[Localization of callose in microspores and pollen grains of Sium latifolium plants under different water regimes].

Results of study of callose content and its topography in mother cells of microspores, microspores and pollen grains in terrestrial and air-aquatic S. latifolium plants growing under different water regimes are presented. The increased content of callose in the microspore walls at tetrad stage and pollen grains is revealed on the basis of fluorescence intensity and quantitative luminescent analysis of terrestrial S. latifolium plants. It is connected, probably, first of all, with the protective role of callose for preservation of water in these cells under water deficiency.

[Response of the glutathione system to chronic irradiation of human population after the Chernobyl accident].

A complex relationship between plasma glutathione level in human population (children living in radionuclide-contaminated regions and the Chernobyl liquidators) exposed to chronic low-level radiation after the Chernobyl accident was demonstrated. The obtained experimental data indicate different responses of the human glutathione system to low (from 0.1 to 20 cSv) and high (from 20 to 150 cSv) doses of ionizing radiation.

[Does the age of people living in uncontaminated and radionuclide-contaminated regions affect glutathione status in blood plasma?]. / Vliiaet li vozrast liudei, prozhivaiushchikh v chistikh i zagriaznennikh radionuklidami regionakh na status glutationa v plazme krovi?

Age-related changes in the content of reduced and oxidized glutathione in peripheral plasma were monitored in human populations (children from birth to 12 years and adults from 20 to 70 years old) living in uncontaminated and radionuclide-contaminated regions after the Chernobyl accident. The content of glutathione in human plasma did not depend on their age and was not genetically fixed. The proportions of humans with different baselines were redistributed in the population exposed to radiation.

[The effect of low doses of radiation on the glutathione status in children and adults after the Chernobyl Atomic Electric Power Station accident]. / Deistvie malykh doz radiatsii na status glutationa detskogo i vzrozlogo naseleniia posle avarii na ChAES.

A level of glutathione in the blood plasma of human population exposed to low-dose radiation after the Chernobyl accident was studied; a complicated character of dose dependence was shown. The response of the glutathione system to low and high radiation doses is different in the children living in the radionuclide-contaminated areas and in the participants of the elimination works.

Vitamin E and A deficiencies in children correlate with Chernobyl radiation loads of their mothers.

Essential lipid bioantioxidants (BAO) (vitamins E and A) and catabolic products of the lipoperoxide cascade (LPC) (diene conjugates, ketodienes, and carbonyls) were determined in blood plasma of children aged 11 days to three years (n = 123) who are residents of regions contaminated with radionuclides (5-40 Ci/km2 of 137Cs) discharged during the Chernobyl power plant accident. Individual antenatal radiation loads Da of children and total radiation doses of their mothers Dm were also determined as external gamma-radiation loads, which correlate with internal radiation doses for permanent residents of contaminated regions. Before examination, therapy with multivitamins containing BAO determined in this work was administered to groups of pregnant women and their children (group I, n = 48) age-matched to a group that received no therapy (group II, n = 99). In group II, reduced concentrations of vitamins E and A decreased to levels indicating severe vitamin deficiency and displayed inverse correlations with Dm and Da. However, in group I these decreases and inverse correlation were only characteristic of initially normal levels of tocopherol. In group II, increases in Dm and Da caused stress-related increases in blood levels of diene conjugates and ketodienes (which was stronger than in group I with increases in Da) and, because of this, E and A vitamin deficiencies. In group I, LPC levels inversely correlated with Dm. We found nine significant correlations of radioloads of mothers with BAO and LPC pathologies of their children. The total pathogenic effectiveness of Dm in relation to LPC and BAO of children is comparable to the effectiveness of Da, which is the most hazardous radiation load. The possibility of existence of a radiation-induced protective response mobilizing BAO from depots into the blood stream is considered. BAO therapy increased the radiation resistance of children. A hypothesis was formulated that the uptake by children of their mother's radioactive Chernobyl isotopes in amounts adequate to their radiation loads is the mechanism of correlations of Dm with long-term pathogenic effects on BAO and LPC systems of children.

Radiation-induced lipoperoxidative stress in children coupled with deficit of essential antioxidants.

Catabolic products of the lipoperoxidative cascade (LPC), including diene conjugates, ketodienes, and carbonyl compounds, as well as essential lipid bioantioxidants (BAO)--vitamins E and A--were determined in blood plasma of 428 children aged 0-7 years residents of areas contaminated with radionuclides after the Chernobyl Power Plant accident. Individual external gamma-irradiation doses (D) were determined. Gamma-irradiation accounted for more than 90% of total radiation loads and correlated with irradiation from absorbed sources in residents of the areas examined. Before examination, oral multivitamin therapy (with preparations containing the BAO determined in this work) was administered to a group of children (group I, n = 90) comparable to the group receiving no therapy (group II). Group II had two to six times higher mean levels of all LPC catabolic products and two to three times lower levels of vitamins E and A in comparison to age-matched subgroups of group I. In group II, individual shifts in the levels of all catabolic products achieved pathogenic stressor magnitudes at maximal regional radiation loads. Antenatal exposure and exposure over the first year of life caused the strongest pathogenic effects. BAO therapy strongly normalized the levels of LPC and vitamins (E and A) at all doses (up to 7 cSv) and increased the radiation resistance of the subjects. A total of 47 linear correlations were found at a p < 0.05 level (r = 0.4 to 0.7 for 54% and p < 0.02 for 87% of equations) between low radiation doses and the extent of deviation of all metabolites studied from their normal levels. The multiplicity of radiation dose--effect correlations found under various conditions suggest that pathological signs found in the children examined were due to irradiation. LPC system disorders developed at low doses and displayed no threshold effect. The data suggest that these disorders resulted from free-radical chain-branched LPC reactions caused by chronic exposure to low doses of strongly ionizing radiation under conditions of BAO deficiency.

[Changes in the level of sulfhydryl groups in the organs and blood of mice administered a highly dispersed iron powder against a background of developing anemia]. / Izmenenie urovnia sul'gidril'nykh grupp v organakh i krovi myshei pri vvedenii vysokodispersnogo poroshka zheleza na fone razvitii anemii.

Alimentary iron deficiency causes significant changes in thiol content: the increase in the content of protein sulfhydryl groups in organs at late stages and the decrease in that of non-protein sulfhydryl groups at early stages of experiment. A preliminary introduction of 10 mg/kg fine iron powder (FIP) into animals fed iron-free food leads to the decrease in sulfhydryl group content in organs and blood of experimental mice. The decrease in sulfhydryl group content at FIP introduction might be connected with changes in activity of glutathione-dependent enzymes.

[Distribution and changes in properties of ferromagnetic iron particles administered to the animal body]. / Raspredelenie i izmenenie svoistv ferromagnitnykh chastits zheleza pri vvedenii ikh v organizm zhivotnykh.

The registration of ESR signals of organs and tissues in the wide range of temperatures permits to study properties and distribution of ferromagnetic particles in animal organisms. High dispersed powder (HDP) of iron (particle dimension--50-100 nm) was administered subcutaneously to mice in the doses 2 and 100 mg/kg weight of animals. One week after the administration HDP was accumulated in the animal organs under study. Two weeks after the treatment of mice with HDP in the dose of 2 mg/kg the ESR signals with g = 2.1 appeared in the animal tissues: liver, spleen, kidney, heart and lungs. Six weeks after the treatment the ESR signals of the studied tissues did not differ from those in control animals.

[Effect of a highly dispersed iron powder on the longevity of irradiated mice]. / Vliianie vysokodispersnogo poroshka zhelezy na prodolzhitel'nost' zhizni obluchennykh myshei.

In experiments on SHK mice it was shown that a single administration of highly-dispersed iron powder (0.2 to 100 mg/kg body weight) 20-30 min before irradiation with different doses exerted both a radioprotective and an enhancing effect and depended on both a radiation dose and a concentration of the iron powder administered.