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V N Lanin

Publications and source records attributed to V N Lanin.

9 recordsLinked to original sources
PubMedDate not supplied

[Reaction between polycytidylic acid and guanosine-5'-triphosphate at neural pH].

The effect of changing the solution acidity in the interval of pH 7--8 on complex formation between polycytidilyc acid (polyC) and guanosine-5'-triphosphate (GTP) has been studied by the equilibrium dialysis and hydrogen ion titration methods. It is shown that in 1 M NaCl at 3 degrees C the complex stoichiometry undergoes changes in a narrow pH interval being equal to 2 poly C: 1 GTP at pH 7,0--7,3 and to 1 poly C:1 GTP at pH 7,6--8,0. In the presence of GTP the apparent pK of poly C protonation increases by 1,4 PK units and becomes equal to 7,1 in 1 M NaCl at 3 degrees C. Thus, the protonated poly-C takes part in the three-stranded poly-C--GTP complex formation. According to Hill's model of cooperative linear adsorption it is shown that the cooperativity of the three-stranded complex formation is greater than of the two-stranded one. The possibility of drastic changes in the structure of biopolymers with small pH changes in neutral region we have found for the poly-C--GTP system as an example may play an essential role in matrix synthesis and other intracellular processes.

Chemical Phenomena↗
PubMedDate not supplied

[A study of the effect of radiation on megakaryocytopoiesis using a mathematical model].

Mathematical modelling used in analysing the postirradiation changes in megakaryocytopoiesis permitted to determine the level of radiation-induced injury in each experiment conducted and to show that megakaryocytopoiesis regulation followed the same mechanism after irradiation as it does normally and after the effect of hydroxyurea and anti-thrombocyte serum. The analysis has demonstrated that after the stem cell death induced by ionizing radiation, the regeneration can be provided by the committed cells, and the level of regeneration is determined by the maturity of precursors.

Animals↗
PubMedDate not supplied

[Mathematical model study of megakaryocytopoiesis. 1. The simulation model, cell steady-state distribution and the number of divisions in a proliferating population].

A method of simulation has been proposed for studying megakaryocytopoiesis. A model has been developed which takes into account the age structure of cell population, the stochasticity of their maturation, and the principles of megakaryocytopoiesis regulation (known from the experiments). The mean number of divisions in a proliferating pool has been determined, as well as the duration of development of the cells with a positive acetylcholine esterase reaction.

Blood Platelets↗
PubMedDate not supplied

[Megakaryocytopoiesis studied in a mathematical model. 2. Regulation of cell differentiation following damage to part of the proliferating bone marrow pool by hydroxyurea].

Analysis of the earlier obtained data on the effect of hydroxyurea on megakaryocytopoiesis by a simulation model has shown that differentiation of proliferating precursors of the megakaryocytes depends on their amount in bone marrow; the time of their involvement in the proliferating pool increases if the number of proliferating cells decreases. Within 24 h after the treatment with hydroxyurea (900 mg/kg), the transit time for the mouse megakaryocytes is reduced by about 14 h due to acceleration of the latest developmental stages. A hypothesis is put forward which accounts for correlation between the duration of proliferative period and the volume and maturation time of megakaryocytes.

Animals↗
PubMedDate not supplied

[Megakaryocytopoiesis studied in a mathematical model. 3. Regulation of cell differentiation in immune thrombocytopenia].

Simulation experiments have shown that just after antiplatelet serum of rabbit blood is introduced into mice the transit time of early proliferating precursors of the megakaryocytes is reduced by about 17 h, the transit time for megakaryoblasts increases, and within 24 h after the treatment the transit time for mature megakaryocytes is reduced b about 17 h. The data obtained confirmed our earlier hypothesis on correlation between the duration of proliferative period and the mean size of megakaryocytes.

Animals↗
PubMedDate not supplied

[Megakaryocytopoiesis studied in a mathematical model. 4. Regulation of cell flow in a transit population].

The role of cells capable of formation of megakaryocytic colonies (CFUm) in regulation of thrombocytopoiesis was studied using a simulation model of megakaryocytopoiesis. The CFUm were shown to be the least differentiated cells involved in regulation of megakaryocytopoiesis in mice upon immune thrombocytopenia and after intravenous injection of hydroxyurea. A correlation was found between the CFUm population productivity and the number of cells in a transit population of the megakaryocytic line which makes it possible to reproduce experimental kinetics in the model. The duration of cell development from CFUm to megakaryocytes is about 3 days.

Animals↗
PubMedDate not supplied

[Polycytidylic matrix complex formation with complementary and noncomplementary purine nucleoside triphosphates].

Misincorportion into I poly(C) : I GTP complex, alpha = (formula: see text), has been determined by using H3-ATP. At ATP total concentration increasing from 6X10(-6) M to 4.5X10(-3) M the alpha value increases going asymptotically onto a plateau. The maximum misincorporation in the studied conditions is I adenilic resiude per congruent to 1400 guanilic ones. No ATP incorporation into the 2 poly(C) : I GTP complex was found. It is shown that misincorporation in non-enzymic recognition is essentially determined both by the difference in complementary and non-complementary monomer stacking and by the difference in their binding with the polynucleotide template.

Adenosine Triphosphate↗