Cytogenetic mechanisms of aneuploidy in somatic cells of chemonuclear industry professionals with incorporated plutonium-239

Risks related to occupational exposure of humans to ionizing radiation remains a focus of attention. Of special importance is the poorly understood effect of ionizing radiation on the rate of numerical chromosome aberrations in human somatic cells. The purpose of this study was characterization of a radiation-induced increase in the rate of aneuploidy induced by incorporated plutonium-239 (²³⁹Pu) in somatic cells of chemonuclear industry workers. Significant differences in the chromosome 2, 7, 8, 12, and Y aneuploidy rate have been found between subjects with incorporated ²³⁹Pu and control subjects have been demonstrated. Chromosome nondisjunction has been found to be the main mechanism of aneuploidy induced by incorporated ²³⁹Pu.     

Altered excitability of rat cutaneous mechanoreceptors during transcranial electrical stimulation

Functional aspects of high, medium, and low threshold mechanoreceptor units were investigated in acute experiments under hexanol-induced anesthesia during transcranial electrical stimulation (TES). It was found that low and medium threshold receptor units ceased responding to mechanical stimulation 1 and 5 min respectively after the start of TES. Firing ended by 18–20 min of TES in high threshold units responding to mechanical stimuli produced by a needle. No significant alteration in parameters of response were produced by TES after prior i.p. or intracutaneous injection of naloxone. Potential mechanisms of TES action are discussed. It is suggested that changes produced in the function of cutaneous mechanoreceptors by TES may be put down to endogenous opioids acting on the receptors.I. P. Pavlov Institute of Physiology, Academy of Sciences of the USSR, Leningrad. Translated from Neirofiziologiya, Vol. 22, No. 4, pp. 495–500, July–August, 1990.     

The lipids of phosphorescent Vibrio albensis bacteria]

The lipid composition of fluorescent vibrios, V. eltor and nonagglutinating vibrios has been studied. In the fraction of polar lipids phosphatidylethanolamine, phosphatidylinositol and cardiolipin and in the fraction of neutral lipids monoglycerides, free fatty acids, diglycerides, triglycerides, sterol esters have been identified. The fatty acid composition of some classes of neutral lipids have been determined. Both similarity and differences between the strains under study in their lipid and fatty acid composition have been established.     

Ethidium and azidoethidium oligonucleotide derivatives: Synthesis,complementary complex formation and sequence-specific photomodification of the single-stranded and double-stranded target oligo- and polynucleotides

Oligodeoxyribonucleotide derivatives containing ethidium or azidoethidium residues attached to 3′ and/or 5′ end were prepared. These derivatives formed tight specific complexes with complementary oligodeoxyribonucleotides where each attached ethidium residue led to an increase of complex T_m by 20–30°C. Tandem complexes of two oligodeoxyribonucleotides containing ethidium residues with an oligodeoxyribonucleotide having two adjacent complementary sequences for these Oligonucleotide were investigated. Photoinduced reactions of a number of ethidium and azidoethidium oligodeoxyribonucleotide derivatives with target complementary single-stranded and double-stranded oligo- and polydeoxyribonucleotides were investigated. The irradiation led to direct photocleavage of the target oligo- or polynucleotide, to formation of hidden (piperidine cleavable) modifications of the target of formation of covalent adducts between ethidium oligodeoxyribonucleotide derivative and the target. In a number of experiments, azidoethidium dyes were demonstrated to be considerably stronger photosensitizers than ethidium ones. Depending on the nature of the target (single- or double-stranded DNA) and on the irradiation conditions, the total damages to the target oligo- or polydeoxyribonucleotides ranged from 10–70% (for ethidium dyes) to 30–80% (for azidoethidium dyes).