[The RH-PA cell line--a source for obtaining the urokinase-type plasminogen activator]. / Kletochnaia liniia RH-PA--istochnik polucheniia aktivatora plazminogena urokinaznogo tipa.

A new cell line (RH-PA) was established on the basis of the human embryonic kidney cell line (RH). The new line produces urokinase type plasminogen activator (PA). The activity of the activator amounted to 150-200 IU/ml estimated with the procedure of fibrin plates. Morphological types of the RH-PA and RH cells were studied and their comparative karyologic analysis was performed. The growth curves of the cells are presented and the dynamics of PA accumulation by them in the maintaining medium is described. Optimal conditions for cultivating the RH-PA cells providing maximum production of the PA were developed.

[A study of the cloned human erythropoietin gene expression in mammalian cells in vitro]. / Izuchenie ékspressii klonirovannogo gena éritropoétina cheloveka v kletkakh mlekopitaiushchikh in vitro.

The human gene coding for the principal factor of erythroid cells differentiation, erythropoietin, has been isolated from the genomic phage library using an oligonucleotide probe for the gene. The construction of series of plasmids carrying the erythropoietin gene under the control of various regulatory elements is reported. Efficiency of the erythropoietin gene expression was estimated by testing of the biologically active erythropoietin in conditioned media 48 h after transient transfection of COS 1 and CHO cell lines.

[Screening of human and animal tissue cell cultures as potential producers of plasminogen activator]. / Skrining kul'tur kletok tkanei cheloveka i zhivotnykh kak vozmozhnykh produtsentov aktivatora plazminogena.

Twenty six normal cell cultures and 19 tumor cell cultures were subjected to screening for plasminogen activator (PA), a fibrinolytic enzyme. It was shown that the enzyme production depended on the nature, origin, type and species of the tissue culture. The primary cultures of the human and calf embryonic kidney cells, permanent cell lines and tumor cells possessed high PA activity. The suspension cell lines did not produce the PA.

[Electron microscopic analysis of the nuclei of human female germ cells at prefollicular stages of development]. / Elektronno-mikroskopicheskii analiz iader zhenskikh polovykh kletok dofollikuliarnykh stadii razvitiia u cheloveka.

Data obtained from electron microexamination of nuclei from female germ cells at the stage of the extrafollicular development in the human fetus are presented.

[Cytoplasmic ultrastructure of human female germ cells at prefollicular developmental stages]. / Ul'trastruktura tsitoplazmy zhenskikh polovykh kletok dofollikuliarnykh stadii razvitiia u cheloveka.

Ultrastructural analysis revealed certain peculiarities of the cytoplasmic organoid behaviour at all the stages of prefollicular development of female fetal ovarian cells.

[Sensitive method of detecting 5-bromodeoxyuridine differentially incorporated into the chromosomes of mammals]. / Chuvstvitel'nyi metod vyiavleniia 5-bromdezoksiuridina, differentsial'no vkliuchennogo v khromosomy mlekopitaiushchikh.

A modified method for fluorochrome staining with acridine orange of chromosome preparations for revealing the BUdR label is described. It has been shown that the alkaline medium used increases the contrast between chromosome areas with varying BUdR content and photoresistance of the staining.

[Scanning electron microscopy of metaphase chromosomes. I. The relation of chromosome morphology to the method of drying the preparations]. / Rastrovaia élektronnaia mikroskopiia metafaznykh khromosom. I. Zavisimost' morfologii khromosom pt sposoba vysushivaniia preparatov.

The surface of metaphase chromosomes fixed in methanol--acetic acid (3 : 1) has been examined by high resolution scanning electron microscopy. The chromosomes were prepared both by the standard method (spread on the slide) and as isolated cells. The absence of microconvules on the surface of air-dried chromosomes is considered to be result of destruction of fibrillar structure by surface tension forces, rather than of covering of chromosomes by remnant of the cytoplasmic membrane.

[Morphological changes in isolated metaphase chromosomes depending on the pH and ionic strength of the solutions]. / Izmenenie morfologii vydelennykh metafaznykh khromosom v zavisimosti ot pH i ionnoi sily rastvorov.

The morphology of isolated unfixed Chinese chamster chromosomes is described in relation to the composition of solutions used for chromosome isolation. The chromosomal morphology was studied with the aid of a flow-chamber and phase-contrast microscopy. Changes in chromosome length and width in relation to pH values (ranging from 2.2 to 9.15) and ionic strength (ranging from 0 to 2.0 M) are detected.

Reversible differential decondensation of unfixed Chinese hamster chromosomes induced by change in calcium ion concentration of the medium.

Differential decondensation of isolated unfixed Chinese hamster metaphase chromosomes was obtained by decreasing the calcium ion concentration in the surrounding medium. A banded appearance of the swollen chromosomes could be observed either directly by phase contrast microscopy or after glutaraldehyde fixation and staining. There was a gradual transition from homogeneously dense to banded and finally to extensively decondensed chromosomes. The patterns induced at different stages were similar to those observed on fixed chromosomes after standard banding procedures (i.e., G-, Cd-, Ag-NOR-staining). Chromosomes decondensation could be reversed by the addition of calcium ions to the medium. Ca ++-dependent reversible differential chromosome decondensation was not observed if the chromosomes were previously treated with 0.35 M NaCl. Chromosome regions which had incorporated BrdU into their DNA were more resistant to a decrease in calcium ion concentration than BrdU non-substituted regions.