[Effect of hydrazine sulfate on nucleic acid metabolism in rat liver tissue during the process of chemical hepatocarcinogenesis]. / Vliianie gidrazinsul'fata na obmen nukleinovykh kislot tkani pecheni krys v protsesse khimicheskogo gepatokantserogeneza.

The development of hepatocellular tumors in rats would show the same character and was observed in the same period (6 months) after either simultaneous administration of a hepatocarcinogen--diethylnitrosoamine (0.02%) and a possible antitumor agent, namely hydrazine sulfate (0.012%) with drinking water, or after the administration of the hepatocarcinogen concerned alone. Hydrazine sulfate failed to reveal any anti-carcinogenic properties, but it would normalize the turnover rate of total RNA and its nuclear components in the rat liver tissue.

[Hepatic RNA resistance to enzymatic degradation in the process of hepatocarcinogenesis in rats]. / Ustoichivost' RNK pecheni k énzimaticheskoi degradatsii v protsesse gepatokantserogeneze u krys.

During hepatocarcinogenesis, induced in rats with diethylnitrosamine (DENA) and lasting for 6 months, the authors have studied the resistance of hepatic RNA to the degradation by serum RNAs, the resistance being served as a criterion of possible changes in the spacial configuration of polynucleotides. In the precancer period the resistance of RNA molecules (total, cytoplasmic, ribosomal and transfer) is found to considerably increase and then to fall within the range of the studied pH (5.1, 7.6 and 8.5). When the malignancy develops, the RNA resistance to enzymatic cleavage increases again and in most cases exceeds the control level. The comparison of the results obtained with those on the effect of the toxic agent (CCl4) allows a conclusion to be made that the carcinotoxic effect of DENA on the rat liver is accompanied with changes in the spacial configuration of cytoplasmic RNA molecules.

[Effect of chronic administration of carbon tetrachloride on turnover of individual RNA fractions in rat liver tissue]. / Vliianie khronicheskogo vvedeniia chetyrekhkhloristogo ugleroda na obmen otdel'nykh fraktsii RNK v tkani pecheni krys

During the carbon tetrachloride treatment of rats (for 24 weeks) the 5-H3-uridine content and incorporation into different rat liver RNA fractions after a short-term exposure of labeled precursor were studied. These fractions were obtained by preparative 2.5% polyacrylamide gel electrophoresis from the nuclear and cytoplasmic RNA extracted by thermal phenol fractionation. CCl4 administration resulted in a decrease in the level of transfer and ribosomal RNAs in the rat liver. Chronic CCl4 treatment led to disturbances of the turnover simultaneousness of different components of rapidly labled RNA.

[Effect of carbon tetrachloride on RNA metabolism in rat liver]. / Vliianie chetyrekhkhloristogo ugleroda na obmen RNK v pecheni krys

The effect of chronic CCl4 treatment on both the liver RNA content and 3H-uridine incorporation was studied. Comparison of morphologic and biochemical parameters allowed to define two successive stages of toxic process resulting in septal fibrosis. The most significant changes in the rat liver rapid RNA turnover were observed during the first 3 months of the toxic agent action. The metabolic disturbances were also manifest in both decreased RNA content and changes of nuclear-cytoplasmic interrelationships in the damage liver tissue.

[Polyadenylic acid rich RNA fractions in primary hepatomas induced with diethylnitrosamine]. / Obogashchennye poliadenilovoi kislotoi fraktsii RNK v pervichnykh gepatomakh indutsirovannykh diétilnitrozaminom

The column chromatography with unmodified cellulose revealed a polyadenilic acid rich fraction of total RNA from diethylnitrosamine induced primary hepatomas and normal rat liver. It was shown that the quantity of this fraction was increased to 3.15 per cent. The 2.5% polyacrylamide gel electrophoresis of the polyadenylic acid rich fraction indicated its different spectra in tumors and normal rat liver, the main change being in bipolymer fractions with sedimentation coefficient 28 S and higher.

[Isoforms of human and animal tumor hexokinase]. / Izoformy geksokinazy opukholei cheloveka i zhivotnykh

In human brain tumors of neuro-ectodermal and meningo-vascular series, using the method of enzymoelectrophoresis and specific tetrazole blue staining, three isoforms of hexokinase were revealed, these differ from each other by their activity and electrophoretic mobility in agar gel. Three isoforms of hexokinase were also found in benign and malignant uterine tumors in females, in 22 A mice hepatoma and homologous intact tissues. Morever, in muscles and muscle tumors (MOP, CRM-1) of rats and of these animals embryos two isoforms of hexokinase were found. The increased rate of hexose phosphorylation in malignant uterine tumors of female patients and in blastomas of mice liver and rat muscles is associated with the increased activity of I and II isoforms of hexokinase. An analogous phenomenon is observed in muscles of rat embryos. On the other hand, the decreased activity of phosphotransferases in blastomas of human brain depends on a decrease in the activity of separate isoforms of hexokinase.