[Effect of Low-Intensity 900 MHz Frequency Electromagnetic Radiation on Rat Brain Enzyme Activities Linked to Energy Metabolism].

The research deals with the effect of low-intensity 900 MHz frequency electromagnetic radiation (EMR), power density 25 µW/cm2, on the following rat brain and blood serum enzyme activities: creatine kinase (CK), playing a central role in the process of storing and distributing the cell energy, as well as alanine aminotransferase (ALT) and aspartate aminotransferase (AST) that play a key role in providing the conjunction of carbohydrate and amino acid metabolism. The comparative analysis of the changes in the enzyme activity studied at different times following the two-hour single, as well as fractional, radiation equivalent of the total time showed that the most radiosensitive enzyme is the brain creatine kinase, which may then be recommended as a marker of the radio frequency radiation impact. According to the analysis of the changing dynamics of the CK, ALT and AST activity level, with time these changes acquire the adaptive character and are directed to compensate the damaged cell energy metabolism.

[Effect of low-intensity 900 MHz frequency electromagnetic radiation on rat liver and blood serum enzyme activities].

The comparative analysis of the rat liver and blood serum creatine kinase, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase and purine nucleoside phosphorylase post-radiation activity levels after a total two-hour long single and fractional exposure of the animals to low-intensity 900 MHz frequency electromagnetic field showed that the most sensitive enzymes to the both schedules of radiation are the liver creatine kinase, as well as the blood serum creatine kinase and alkaline phosphatase. According to the comparative analysis of the dynamics of changes in the activity level of the liver and blood serum creatine kinase, alanine aminotransferase, aspartate aminotransferase and purine nucleoside phosphorylase, both single and fractional radiation schedules do not affect the permeability of a hepatocyte cell membrane, but rather cause changes in their energetic metabolism. The correlation analysis of the post-radiation activity level changes of the investigated enzymes did not reveal a clear relationship between them. The dynamics of post-radiation changes in the activity of investigated enzyme levels following a single and short-term fractional schedules of radiation did not differ essentially.

[Influence of ionizing radiation on enzymatic activity and state of nucleus-nucleolar apparatus in rat hepatocytes].

The effects of a single exposure of rats to the whole-body roentgen irradiation at the doses of 3.5 Gy and 4.5 Gy on the activity of creatine kinase, purine nucleoside phosphorylase, alanine aminotransferase, aspartate aminotransferase, as well as on the state of the nuclear-nucleolar apparatus in rat hepatocytes on the 6th and 13th days after radiation exposure have been studied. Irradiation at the above doses induced changes in the levels of enzymatic activity of different values and different directions within the same time periods, as well as oscillating changes in this type of enzymatic activity over time. This demonstrates various radiosensitivity and adaptation abilities of these enzymatic activities. The changes in the enzymatic activity significantly correspond to the changes in the morphometric indices of nuclear-nucleolar apparatus of hepatocytes, as well as the distribution of hepatocytes within the ploidy classes: in particular, stabilization of the enzymatic activity on the 13th day after irradiation correlates with the increased transcriptional activity, which is detectable through the increased number of nucleoli per nucleus and the expanded space of a hepatocyte nucleus. The compensation mechanisms are likely to be targeted at the changes in the functional activity of surviving hepatocytes, rather than at the replacement of the damaged cells by the new ones.

[Role of creatine kinase and its substrates in the central nervous system in norm and in various pathologies].

There is presented review of recent publications providing current understanding of role of the creatine kinase-creatine phosphate system and creatine, substrate of creatine kinase, in metabolism of cell and specifically of cells of the central nervous system. Particularly noted are the protector role of creatine at mitochondrial and bioenergetic cell dysfunction and potential significance of creatine supplements at treatment of neurodegenerative and other diseases.

[Some inhibitors of purine nucleoside phosphorylase].

Purine nucleoside phosphorylase (PNP) catalyzes reversible phosphorolysis of purine deoxy- and ribonucleosides with formation (d)Rib-1-P and corresponding bases. PNP plays a leading role in the cell metabolism of nucleosides and nucleotides, as well as in maintaining the immune status of an organism. The major aim of the majority of studies on the PNP is the detection of highly effective inhibitors of this enzyme, derivatives ofpurine nucleosides used in medicine as immunosuppressors, which are essential for creating selective T-cell immunodeficiency in a human body for organ and tissue transplantation. The present work is devoted to the study of the effects of some synthetic derivatives of purine nucleosides on activity of highly purified PNP from rabbit spleen and also from human healthy and tumor tissues of lung and kidneys. Purine nucleoside analogues modified at various positions of both the heterocyclic base and carbohydrate residues have been investigated. Several compounds, including 8-mercapto-acyclovir, 8-bromo-9-(3,4-hydroxy-butyl)guanine, which demonstrated potent PNP inhibition, could be offered for subsequent study as immunosuppressors during organ and tissue transplantation.

[Purine nucleoside phosphorylase inhibitors and their clinical significance].

PNP catalyzes a reversible phosphorolysis of purine deoxy- and ribonucleosides with formation of (d)Rib-1-P and appropriate bases. PNP plays a leading role in the cell metabolism of nucleosides and nucleotides, as well as in maintaining the immune status of an organism. The major purpose of the majority of studies on the PNP is the detection of high-performance enzyme inhibitors, derivatives of the purine nucleosides, which are used in medicine as immunosuppressors. It is well known that the latter are necessary for creating a selective T-cell immunodeficiency in a human body under organs and tissue transplantation. The review discusses the issues related to deliberate synthesis of effective, metabolically inert, and low-toxic PNP inhibitors. It also analyzes the available studies on substrate and inhibitory properties of the analogues of purine nucleosides, as well as research on the structural factors which reinforce the inhibitor activity of those analogues. The inhibitors which are either used in medical practice or are currently at a stage of preclinical testing are described. The inhibitors which are more efficient in their influence on the PNF from tumorous tissues are of special interest. Using PNP inhibitors in case of a number of pathologies denotes the importance and promise of research on both the enzyme and the compounds affecting its activity.

[Creatine kinase of the human placenta]. / Kreatinkinaza platsenty cheloveka.

Studies have been made of the activity and isoenzymic spectrum of creatine kinase from human placenta at various stages of its development. Pure preparation of the enzyme was obtained which exhibited low specific activity and intermediate (between MB and BB isoenzymes of creatine kinase) electrophoretic mobility. Some of the properties of this enzyme are described and compared to those of creatine kinase from the brain of rabbits.

[Interaction of rabbit muscle creatine kinase with a reactive ATP derivative-ATP gamma-4(N-2-chloroethyl-N-methyl-amino)-benzylamidate]. / Vzaimodei kreatinkinazy iz myshts krolika s reaktsionnosposobnym proizvodnym ATP-4-(N-2-khlorztil-N-metilamino)-benzil-gamma-amidom ATP.

The interaction of AGP gamma-4(N-2-chloroethyl-N-methyl-amino)-benzylamidate with rabbit muscle creatine kinase was studied. ATP gamma-4-(N-2-hydroxyethyl-N-methyl-amino)-benzylamidate acts as competitive inhibitor of creatine kinase. The Km value for ATP and the Ki value for the gamma-analog have been determined. A complete inactivation is observed when 1 mole of the reagent binds per 1 mole of the enzyme. The modification of the second subunit of creatine kinase is achieved at higher concentrations of the reactive ATP analog. The reactive ATP derivative is shown to be an affinity reagent for this enzyme. The possibility of interaction between the subunits of creatine kinase is discussed.

[Changes in the functional activity of macrophages, their morphology and metabolism under the influence of several biologically active substances]. / Izmeneniia funktsional'noi aktivnosti makrofagov, ikh morfologii i metabolizma pod vliianiem nekotorykh biologicheski aktivnykh veshchestv

The functional activites of peritoneal macrophages, their morphology and metabolism under the effects of some metabolic inhibitors and various biological ngents were studied. A correlation between functions of macrophages (speading on glass, pinoctosis of virus particles), changes in their metabolism (RNA and protein synthesis; specific activity ofcreatinkinase and catepsin), properties of the macrophages plasma membrane, and the number of lysosomes, was found.