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Biomedical subjects

V V Osipov

Publications and source records attributed to V V Osipov.

At least 19 recordsLinked to original sources
PubMed2004

High-frequency spin-valve effect in a ferromagnet-semiconductor-ferromagnet structure based on precession of the injected spins.

A new mechanism of magnetoresistance, based on tunneling emission of spin-polarized electrons from ferromagnets (FM) into semiconductors (S) and precession of electron spin in the semiconductor layer under external magnetic field, is described. The FM-S-FM structure is considered, which includes very thin heavily doped (delta-doped) layers at FM-S interfaces. At certain parameters the structure is highly sensitive at room temperature to variations of the field with frequencies up to 100 GHz. The current oscillates with the field, and its relative amplitude is determined only by the spin polarizations of FM-S junctions.

Journal Article↗
PubMed2004

[Neural network model of treatment policy decision in patients with ulcer disease].

Based on neuronetwork computer technologies expert neuronetwork complex Axon was developed providing individual prognosis of ulcer disease and recommendations. The base of this expert system is information data base consisting of two blocks. The first block consists of detailed information about 634 patients with gastric ulcers (GU), the second block - about 417 patients with duodenal ulcers (DU). Control evaluation of the system demonstrated that the coefficient of sensitivity in patients with GU was 0,706 - 0,724, coefficient of specificity - 0,701-0,790. Coefficient of sensitivity in patients with DU was 0,765-0,817, coefficient of specificity - 1,000-0,877. The best neuronetwork evaluation was carried out in 57 new hospitalized patients. In 7 of 10 operated patients indications for surgery were based on combination of prognostic and clinical data. Only 2 (4,3%) of 47 patients demonstrated disagreement of prognostic and clinical data. In comparison of results of complications prognosis with real clinical results in surgical group 7 (70,0%) of 10 patients demonstrated agreement of these data. In 32 (74,4%) of 43 patients treated conservatively prognosis of complications corresponded to real clinical data.

Decision Making, Computer-Assisted↗
PubMed2001

Chaotic domain patterns in periodic inhomogeneous magnetic films.

A study of domain structures in thin inhomogeneous ferromagnetic films is presented. It is shown that smooth and small inhomogeneities in the exchange and anisotropy parameters yield very complex domain structures. We show that the domain walls are fixed near certain inhomogeneities but do not repeat their space distribution. We found that there are metastable chaotic domain patterns in periodic inhomogeneous films. These results are relevant for magnetoresistive devices.

Journal Article↗
PubMed2000

[Use of neural network computer technology in the determination of therapeutic strategy in patients with stomach and duodenal ulcer].

The authors present the expert neural network programmed complex "Axon" allowing the prognosis of the course of ulcer disease of the stomach and duodenum to be made. On the basis of the prognosis obtained certain medical strategy can be recommended. The neural network in which the data of treatment of 909 patients with ulcer disease of the stomach and duodenum had been introduced was taken as a basis of the complex. The program is registered in the Russian copyright agency for PC programs, data base and topologies of integrated circuits. The authors consider that the approach proposed will allow the correct medical policy to be chosen which can lead to better results of treatment of patients with ulcer disease and thus the 100 years long contradictions between different specialists in determining medical policy for such category of patients will be overcome.

Duodenal Ulcer↗
PubMed2000

[The use of artificial neuronal networks in the treatment of peptic ulcer].

Today the use of artificial neuronic nets (ANN) is the most perspective method in the prediction of clinical course and in the choice of correct therapeutic tactics. The experimental complex "Axon" with the software was created in the hospital that permitted to predict the course if gastric and duodenal ulcers. We introduced the data of 909 patients that contained the anamnesis, results of objective examination and late results of the treatment. These data has become the base for training and formation of ANN similar to the structure of human cerebral cortex. Having received the information about a new patient and using the previous experience of therapy of 909 patients mentioned above the trained ANN gives an accurate information concerning this patient. It is presented in the form of protocol of prognosis of ulcer clinical course, the probability of complication development, the results of conservative and surgical treatment. The protocol includes the conclusion with recommendations on the choice of therapeutic tactics.

Chronic Disease↗
PubMed1999

Theory of spike spiral waves in a reaction-diffusion system.

We discovered a type of spiral wave solutions in reaction-diffusion systems--spike spiral wave, which significantly differs from the spiral waves observed in the models of FitzHugh-Nagumo type. We present an asymptotic theory of these waves in the Gray-Scott model [Chem. Sci. Eng. 38, 29 (1983)]. We derive the kinematic relations describing the shape of this spiral, and find the dependence of its main parameters on the control parameters. The theory does not rely on the specific features of the Gray-Scott model and thus is expected to be applicable to a broad range of reaction-diffusion systems.

Journal Article↗
PubMed1998

Application of free-flow electrophoresis for isolation and purification of proteins and peptides.

Free-flow electrophoresis (FFE) has been applied to the separation and purification of a variety of proteins and polypeptides: bee venom, tumor necrosis factor, interleukin-1beta, interferon-gamma and superoxide dismutase. FFE at constant pH and conductivity of the carrying buffer is shown to be efficient at various separation schemes. In some cases, the method allows us to obtain proteins with a purity of more than 90% at a productivity of 20-30 mg/h. An electrophoretic apparatus with a new, multi-sectional construction of the electrophoretic chamber and a system for cross-displacement of carrying buffer in the chamber is described.

Animals↗
PubMed1997

[The choice of the surgical treatment method in gastric peptic ulcer].

Results of treatment of 351 patients with ulcer disease of the stomach have been analyzed. Operations were performed on 235 of them. It has been shown that resection of the stomach should be performed with ablation of the total lesser curvature. The resection volume depends on the spread of dysplastic alterations in the mucosa and can be as large as a subtotal resection. Better immediate and long-term results were obtained after resection of the stomach by the Roux method.

Aged↗
PubMed1996

[Gastric juice acidity in gastric ulcer].

Gastric juice acidity was examined in 131 patients with gastric ulcer. In 31 (23.7%) patients it appeared to be high, in 57 (43.5%)-normal, in 42 (32.8%)-low. In 28.6% cases the pepsin concentration was high, in 26.5%-normal, in 44.9% - low. In elder patients, patients with cardial ulcer, plural and combined ulcers, big size ulcers, long-term ulcer anamnesis the rate of low acidity increases. Among patients with unsatisfactory results of conservative treatment 15.8% had high acidity and 38.7% low acidity. Low acidity is an unfavorable prognostic factor.

Adult↗
PubMed1993

Expression of mRNAs encoding the alpha 1 and the beta 1 subunits of Na+, K(+)-ATPase in human lymphocytes activated with phytohaemagglutinine.

Increase in Na+, K(+)-ATPase mRNAs was detected in activated lymphocytes by the RT-PCR method. alpha 1 subunit mRNA gradually increased with time and by 36 h was 2.4 times higher than at the start. Increase in the beta 1 mRNA was transient reaching a maximum in the 8 h probe and declining to the initial level in the 24 and 36 h probes. The elevation of Na+, K(+)-ATPase mRNAs does not underlie a cycloheximide-inhibited increase in cation pumping peculiar to the prereplicative period as can be judged from the fact that Act D fails to eliminate PHA-induced enhancement of pump fluxes.

Cells, Cultured↗
PubMed1993

[Surgical treatment of stomach ulcer].

The choice of the operative method in gastric ulcer is determined by the peculiarities of ulcer development mechanism and the role of acid production in the process and by oncological reasons. Bearing in mind that acid production is of little significance in the pathogenesis of gastric ulcer, while malignant degeneration of gastric ulcers is quite a reality, the authors consider resection of the stomach to be the most expedient operative method in its ulcer. Among 73 patients with gastric ulcer 70 (95.94%) were treated by resection of the stomach. Depending on the localization of the ulcer, the volume of the resection ranged from antrumectomy to gastrectomy. Five (7.14%) patients died after the operation, 3 from thromboembolic complications and 2 from peritonitis. The late-term, results were studied in 53 (81.54%) patients and were found to be good in 44 (83.02%), satisfactory in 5 (9.43%), and poor in 4 (7.55%) patients. Malignant degeneration of the ulcer was encountered in 7 (10%) of the 70 patients who were operated on. The authors prefer resection of the stomach with the formation of Roux-en-Y anastomosis which prevents reflux gastritis, recurrent ulcer, and the development of tumors. This is confirmed by the late-term results.

Adult↗
PubMed1991

[The transport and distribution of monovalent cations during the blast transformation of human peripheral blood lymphocytes activated by phytohemagglutinin].

Potassium (rubidium) influx, sodium and potassium contents, as well as size distribution, DNA and protein contents and synthesis have been examined in PHA-activated human lymphocytes within 0.5-72 h. A complex set of ionic events was found to include at least two stages of the increase in potassium and sodium contents per g cell protein and in ouabain-sensitive potassium influx which are preceded by a decrease in potassium content by almost 17% within the first 2-5 h. The kinetics of potassium and sodium changes has own pattern for each of cations, thus indicating definite changes in the ouabain-resistant transport of potassium and sodium during the G0----G1----S progression. The late increase in potassium content per g cell protein was found to correlate with the growth in cell size. This finding confirms the rule which was stated earlier for other animal cells, i. e. cells that prepare to proliferate are to raise their potassium per g cell protein up to the level of 0.8-1.0 mmole (Vereninov. Marakhova, 1986).

Biological Transport↗
PubMed1991

[The relationship between the cation and protein content, cationic transport and the rate of protein synthesis detected in cells in the presence and in the absence of ouabain].

The measurements were made of monovalent cation (K+ + Rb+, Na+) and protein contents, of leucin incorporation into the protein (protein synthesis), and of ouabain-sensitive K+ influx during the growth of the Jurkat culture cells in the presence or in the absence of ouabain. All the data were calculated per cell. The time dependences of these parameters are nonlinear [correction of unline] curves. The results of three independent measurements are not reproduced. The problem was to find out an intracellular "main" parameter, so that the dependences between this and the rest of parameters be of line character. It has been found that it is the protein synthesis rate that may be taken as the main parameter, because between the protein synthesis rate and all the other parameters there is the line connection. Comparative results obtained with or without ouabain showed that K+ and Na+ concentrations in the cell were different, although the constants of the rate of protein synthesis were the same. This points to the same type of change of the protein synthesis process in the cells growing with or without ouabain.

Biological Transport↗
PubMed1988

[Interrelation of the dynamics of antigen intake into bone marrow and the proliferation of hematopoietic stem cells].

As it is previously shown (Tsyrlova et al., 1986), the level of humoral immune response is not only determined by the reaction of peripheral lymphoid system on antigenic effect, but also is bound up with the observed stem blood cell (SBC) proliferation in bone marrow (Frindel et al., 1976, Kozlov et al., 1982). Dynamics of label accumulation in bone marrow was examined when injecting antigen--sheep red blood cells labeled by radioisotope 51Cr, 125I. The peak of label accumulation in bone marrow, accompanied by the increase in proliferative SBC, was observed on the 3rd day after antigen injection. Furthermore in the course of immunization 51Cr labeled macrophage assortment was changed in time in such a way that a greater number of macrophages was accumulated in bone marrow on the 3rd and 4th days in the immunized animals in comparison with the intact ones. The macrophages in bone marrow are likely to take part in antigen uptake and to mediate its effect on SBC proliferation.

Animals↗