Correlation between family and age of manifestation of lung and colon cancer

The probability to develop lung cancer before 80 years of age is 1.67 and 0.18% for the male and female populations of Kharkov, respectively; the probability to develop large-intestine cancer is 0.92 and 0.49%, respectively. The correlation coefficient (r) of the age of manifestation (AM) of cancer in parent-offspring pairs is 0.47. These correlation coefficients for the father-son, mother-daughter, mother-son, and father-daughter pairs are 0.64, 0.49, 0.44, and 0.37, respectively. If the parent has lung cancer, the correlation is stronger (r = 0.71). On average, cancer is manifested in offspring earlier than in parents (57 and 63 years, respectively); the differences in the father-daughter and mother-son pairs are 8.2 and 2.8 years, respectively. The best prognostic parameter is the AM of cancer in the father with respect to the AM in the son (byx = 0.45).     

Dynamics of reorganization of instrumental food getting behavior of monkey under conditions of reinforcement delay

Six adult monkeys (Macaca fascicularis) were trained to switch on a lamp by pressing the lever, to hold the lever for not less than 1 s (the lamp being switched on), and get a portion of food. After reaching a learning criterion, the delay between the lever pressing and food reinforcement was increased to 2.5 s. The experimental procedure was repeated in three experimental sessions with 2-month between-session intervals. It was shown that the retraining process after the uneven change in the delay duration developed in three stages: (1) stage of emotional hyperreactivity that reflected a mismatch between the cation and absence of the expected result; (2) stage of intermediate stabilization, when the percent of efficient attempts was the same as under conditions of 1-s delay; (3) stage of purposive instrumental lever holding till the moment of reinforcement presentation.     

Inhibition of the activity of membrane-bound Ca2+-ATPase in the sarcoplasmic reticulum fragments of rabbit skeletal muscles by the alkaloid sanguinarine

Sanguinarine, a plant DNA-intercalator, is shown to inhibit the enzyme activity of the membrane-bound Ca2+-ATPase of rabbit skeletal muscle sarcoplasmic reticulum fragments. This inhibition could be interpreted by the well known ability of this alkaloid to interact with sulphydryl groups of the enzymes. Sanguinarine is a weaker inhibitor of this reaction than a sulphydryl group poison Ag+. The I50 is 3.10(-6) M for Ag+ and 7.10(-5) M for sanguinarine in the reaction medium with NO3- substituted for Cl-. In the standard reaction medium containing Cl-, the I50 for sanguinarine is 1.8.10(-4) M. In this case sanguinarine activates Ca2+-ATPase at low concentrations presumably because of uncoupling ATP hydrolysis from Ca2+ transport through membrane. Other agents studied are: DNA-intercalators--ethidium bromide, acriflavine, acridine orange; DNA-complexing antibiotics--actinomycin D, and olivomycin, alkaloids, quinine, morphine, berberine and an uncoupler of oxidative phosphorylation 2,4-dinitrophenol. These were found not to inhibit Ca2+-ATPase activity up to the concentrations of 10(-3)-10(-4) M.     

Temperature-dependent structural changes in complexes of tRNA(adenine-1)-methyltransferase from Thermus thermophilus HB8 and tRNA studied by optical and electron microscope methods

The complexation of tRNA (adenine-1-)-methyltransferase from Thermus thermophilus HB8 (E.C.2.1.1.36) with Escherichia coli tRNA(Phe) and yeast tRNA1(Val) was investigated in a temperature range from 20 to 90 degrees C. The quantity of methylase subunits bounded with tRNA and the association constant (Ka) were determined by means of fluorescence quenching of the enzyme tryptophane residues by tRNA molecules. The number of enzyme subunits bounded with one tRNA molecule at temperatures 20-70 degrees C is equal to 8 +/- 2. The Ka values increase from (2 divided by 3).10(7) at 20 degrees C up to 8.5.10(7) M-1 at 70 degrees C. The temperature increase from 70 to 90 degrees C causes a decrease in the enzyme specific activity and in Ka values. In the temperature range from 75 to 90 degrees C a cooperative transition of methylase macromolecules into associates was observed. This association is accompanied by an increase of UV-light scattering and of fluorescence polarization coefficient of methylase tryptophane residues. In the absence of tRNA the size of enzyme associates (d) is evaluated to be more than 320 nm (d greater than or equal to lambda-320 nm), in the presence of tRNA-less than 320 nm (d much less than lambda-320 nm). An electron microscopic investigation of methylase and its complexes with tRNA at 20 degrees C revealed disk-like particles with a diameter and height of 8-11 nm and 4-5 nm, respectively. These disk-like methylase preparations dialized against distilled water form flexible polymeric rods with a diameter of 10-12 nm and the length of about several hundreds nm. During complexation of methylase with tRNA, in the same conditions as the dializes was carried out, large associates were not revealed.     

EcoRV restrictase: physical and catalytic properties of homogenous enzyme

With the use of the strain-overproducer restriction endonuclease R.EcoRV was isolated and purified to homogeneity. The molecular mass of the enzyme was determined by gel filtration and polyacrylamide gel electrophoresis to be 25 000 daltons. According to the data of immunological tests R.EcoRV differs in its antigenic characteristics from restriction endonucleases R.EcoRI and R.EcoRII. Dependence of enzyme activity on pH, ionic strength, temperature, presence of divalent cations (Mn2+, Mg2+, Co2+, Zn2+, Ni2+ and Cd2+) and organic solvents (glycerol, dimethylsulfoxide, ethanol) has been studied. It was shown that under conditions of replacement of Mg2+ for Mn2+ or after addition of organic solvents relaxation of R.EcoRV specificity takes place. It was shown also that R.EcoRV is able to digest T-even bacteriophage DNAs with different types and extents of modification. DNA modified by the action of MR.EcoRV system in vivo is susceptible to R.EcoRV in vitro. Under conditions of relaxed specificity noncanonical sites are susceptible to R.EcoRV attack. The fragments resulted may be cloned in canonical pBR322 EcoRV site.     

Investigation of the tissue growth processes in porous implant

Investigation of the cell (osteocytes, fibroblasts and keratinocytes) adhesion and penetration in pores of the titanium pylon in vivo on the laboratory animals (Wistar rats) has been performed. The titanium pylon has been implanted in bone of a rat's thigh residuum. Electronic scanning and morphological analysis demonstrated the certain integration of the pylon with the surrounding tissues. The latter opens a possibility for development of direct skeletal attachment of limb prostheses.     

Effect of liver chromatin DNAse on closed circular DNA of PM-2 phage and simian virus 40]

Comparative effect of the DNAse from rat liver chromatin and Neurospora crassa endonuclease S1 on closed circular superhelical DNA of PM-2 phage and Simian Virus 40 is studied. It is shown that both of them--the DNAse from chromatin proteins and endonuclease S1--are specific to single-stranded regions in DNA molecular. It is suggested that chromatin protein DNAse participates in reparation processes.