[Fusion of Erwinia chrysanthemi spheroplasts in an electric fields].

A new approach has been elaborated for electrofusion of Erwinia chrysanthemi spheroplasts. The new approach consists of superimposition of high voltage impulses on the pellet of tightly contacting cells in the course of centrifugation. The mixture of spheroplasts of two genetically marked strains was placed into the special centrifuge chambers and spinned for 15 min at 2500 g to get a compressed pellet between chamber electrodes.

[Principles of cytogenetic examination for detecting occupational hazards].

The main principles are stated of carrying out a cytogenetic examination of human populations on the basis of critical analysis of data from literature and the authors' own experience in this field. The method for estimation of sister chromatid exchanges is shown expedient to be used together with the chromosome aberration analysis in carrying out cytogenetic examinations. Statistically ascertained approaches are adduced to select the necessary amount of persons examined in groups and the number of cells for analysis when using methods for estimation of sister chromatid exchanges and chromosome aberrations.

[Statistical analysis of the elimination of chromosome-type aberrations and the fate of the aberrant cells].

The regularities of elimination of gamma-ray induced chromosome aberrations in human nonstimulated lymphocytes and the fate of aberrant cells have been studied. The cells at the first, second and third post-irradiation divisions were identified by the technique of differential staining of sister chromatids. A mathematical model has been suggested to describe the processes of formation, multiplication and death of the cells with dicentrics.