[Chemical factors regulating cell division in the body]. / Khimicheskie faktory, reguliruiushchie delenie kletok v organizme.

Experimental data are considered, suggesting existence of factors specifically regulating division of hepatocytes. The factors, found in regenerating liver tissue and its blood serum of hepatectomized animals, stimulated the cell division. The substance from intact liver cells or liver chalones inhibited the division of hepatocytes.

[Effect of chalones from liver tissues of intact rats on DNA synthesis and mitotic activity in hepatocytes of regenerating liver]. / Vliianie khalonov pecheni intaktynkh krys na sintez DNK i mitoticheskuiu aktivnost' gepatotsitov regeneriruiushcheí pecheni.

Activity of G1 and G2 chalones was found in liver tissue extract. The chalone G1 as compared with the chalone G2 was responsible for longer effect on mitosis of regenerating liver cells. The influence of the chalones was reversible. DNA synthesis was inhibited similarly after treatment of the animals with 1.0, 0.5 or 0.25 mg of the liver tissue extract per 1.0 g of the body mass.

[Several approaches to purifying rat liver G2-chalone]. / Nekotorye podkhody k ochistke G2-khalona pecheni krys.

An attempt was made to isolate the liver tissue chalone blocking the transition of hepatocytes from G2 period of the cell cycle into mitosis/g2-chalone/. The purification was carried out using gel filtration through Sephadex G-75 and hydroxyapatite chromatography as well as by means of ultrafiltration through Diaflo membranes XM-300, XM-100 and PM-10. The biologically active preparation, obtained by these two procedures, was purified 100-fold. Molecular mass of G2 chalone was apparently less then 10,000; it penetrated through PM-10 membrane. The chalone appears to form complexes with high molecular carriers.

[G2 period and entrance into the resting state at different stages of mouse ascitic hepatoma 22A development]. / Period G2 i vykhod iz nego v sostoianie pokoia na raznykh stadiiakh razvitiia astsitnoi gepatomy 22A myshei.

In the course of AH22A development the size of G2 subpopulations (G2 period cell of the mitotic cycle) changes relatively little for the most part, slightly decreasing in the terminal stage. Five days before the terminal stage of AH22A the cell subpopulation was found to be in the reversible resting R2 stage (the population egressed from the mitotic cycle in G2 period). The size of the population increased with tumor growth. In the terminal stage, however, its size was insignificant (47%). Therefore, it is not possible to prove that cells accumulate in considerable amounts in the reversible resting R2 stage. This circumstance and a decrease in the size of G2 subpopulation and cell population in advanced tumors during the reversible resting R2 stage evidence that the latter one is of a relatively short duration in the course of cell egress from G2 period of the mitotic cycle in the irreversible resting stage.

[Treatment of acute left-ventricular insufficiency complicated by tachyarrhythmia under conditions of cardiological emergency service]. / Lechenie ostroi levozheludochkovoi nedostatochnosti v sochetanii s takhiaritmiiami v usloviiakh kardiologicheskoi skoroi pomoshchi.

The article analyses 188 cases treated for acute left ventricular insufficiency (ALVI) in different forms of tachyarrhythmia. It was established that in patients with supraventricular paroxysmal tachycardia ALVI develops when the rate of cardiac contractions is 180 +/- 3/min on the average, whereas in patients with cardiac fibrillation it develops when the rate of contractions is 163 +/- 4/min. For successful treatment of ALVI of a tachyarrhythmic character it is necessary to restore the sinus rhythm or slow down the rhythm of cardiac contractions in patients with supraventricular paroxysmal tachycardia to 113 +/- 5/min on the average and in patients with cardiac fibrillation to 118 +/- 2/min. Isoptin and obsidan produce the highest decelerating effect. In half of the patients with tachyarrhythmia. ALVI was relieved by means of antiarrhythmic agents among which obsidan and isoptin proved most effective.

[Stimulating effect of histones on DNA synthesis in the regenerating rat liver]. / Stimuliruiushchee deistvie gistonov na sistez DNK v regeneriruiushchei pecheni krys.

Effect of exogenous histones, nuclear globulins and acid proteins on DNA synthesis is studied in regenerating liver of rats in which the synthesis of their own proteins and thus DNA replication are inhibited by cycloheximide. In these conditions histones from regenerating rat liver are found to stimulate 3H-thymidine incorporation into DNA of hepatectomyzed rat liver. Nuclear globulins and acid proteins from regenerating liver, and histones from intact liver produced no stimulating effect on DNA sythesis.

Study of the nature of the growth-inhibiting factor in embryos of mice of the mutant line brachypodism-H.

An extract from 13-day embryos of mice homozygous with respect to the bp-H gene contains a growth-inhibiting factor (GIF), which inhibits the growth of normal bones in vitro. The activity of the GIF depends on the concentration of the extract in the culture medium. The sensitivity of the GIF to heating and proteolytic enzymes is an indication of its protein nature. The precipitation of the GIF from the embryonic extract with ammonium sulfate, followed by fractionation on columns with Sephadex G-200 and DEAE-Sephadex gave a 400-fold degree of purification. The active growth-inhibiting preparation obtained is represented by three proteins, which migrate slowly in electrophoresis in polyacrylamide gel. The molecular weight of the basic component is 76,000.