Estimation of current maximum permissible levels of total specific activity of radionuclide mixture in the liquid forms of drugs and medicinal raw materials]

Algorithm of assessment of allowable levels of the total specific activity of radionuclides in liquid medicaments and medical raw materials was worked up. The key radionuclides were Strontium-90, Caesium-134 and -137.     

Some aspects of structural disturbances in the DNP complex when damaged by N-nitroso-N-methylurea

The effect of solubilization of deoxyribonucleoproteins (DNP) in a medium of near-physiological ionic strength after treatment with the mutagen N-nitroso-N-methylurea (NMU) is highly dependent on the NMU concentration. To convert DNP into a soluble state, the critical number of groups in the DNA and protein must evidently be modified. On the basis of data obtained by the circular dichroism method and by viscosimetry it is concluded that after treatment with NMU the DNP complex becomes soluble in solvents with near-physiological ionic strength largely as a result of labilization and dissociation of the DNA-protein bonds.Laboratory of Biophysics, Institute of Medical Genetics, Academy of Medical Sciences of the USSR. Sector of Kinetics of Chemical and Biological Processes, Institute of Chemical Physics, Academy of Sciences of the USSR. Laboratory of Physical Methods of Investigation, D. I. Ivanovskii Institute of Virology, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR S. S Debov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 81, No. 6, pp. 674–677, June, 1976.     

Detection of mutations in Mycobacterium tuberculosis genome determining resistance to fluoroquinolones by hybridization on biological microchips

We developed a method of identification of Mycobacterium tuberculosis with simultaneous evaluation of the sensitivity to fluoroquinolones on a biological microchip array. The method of multiplex two-staged PCR followed by hybridization of a biochip makes it possible to detect 8 mutant variants of gyrA gene occurring in fluoroquinolone-resistant strains (∼85% all resistant forms) within 1 day. Using this method we analyzed 107 cultures isolated from patients with tuberculosis and 78 sputum samples. Mutations in gyrA gene were detected in 48 (92%) resistant strains. Natural S95T polymorphism in gyrA gene was detected in all resistant and in 76% sensitive strains. The sensitivity and specificity of the proposed method calculated on the basis of the analysis of sputum samples (n=78) were 94 and 100%, respectively. __________ Translated from Byulleten’ Eksperimental’noi Biologii i Meditsiny, Vol. 145, No. 1, pp. 115–120, January, 2008     

Determination of glucokinase and hexokinase activity in liver extracts previously purified on Molselect G-50 dextran gel

Hexokinase and glucokinase activity in the supernatant of a rabbit liver homogenate obtained at 18,000g was determined by a spectrophotometric method. Preliminary purification to remove low-molecular-weight components by gel filtration on Molselect G-50 dextran was shown to prevent reduction of NADP unconnected with the hexokinase reaction.Presented by Academician of the Academy of Medical Sciences of the USSR V. S. Il'in.Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 82, No. 7, pp. 891–892, July, 1976.