[Surgical treatment of cervical spine tumors involving vertebral artery in children: analysis of small sample siz]. / Khirurgicheskoe lechenie opukholei sheinogo otdela pozvonochnika v oblasti pozvonochnoi arterii u detei: analiz maloi klinicheskoi serii.

OBJECTIVE: To analyze the features of cervical spine tumors involving vertebral artery in pediatric patients. MATERIAL AND METHODS: A single center 2-year retrospective cohort includes 7 children with cervical spine tumors involving vertebral artery. Demographic data, duration of diagnostic process, clinical and radiological manifestations, features of surgical treatment, morphology, and postoperative outcomes were studied. We analyzed the features of vascular imaging, pre- and intraoperative manipulations on the vertebral artery. RESULTS: Mean age of patients was 13.3 years, duration of diagnostic process - 13.1 months. Cervicalgia was the most common complaint. Malignant process was found in 2 cases. Preoperative temporary balloon occlusion test and subsequent endovascular embolization of vertebral artery were performed in 1 case, intraoperative ligation - in 1 patient. Injury and subsequent tamponade were noted in another patient. There were not neurological complications associated with arterial occlusion in postoperative period. CONCLUSION: Our group was compared with the data from 14 manuscripts comprising 21 children with similar cervical spine lesions. The decision making algorithm for surgical treatment of patients with cervical spine tumors involving vertebral artery is proposed.

[Novel biocatalyst for productions of S-(-)-2-[6-benzyloxy -2,5,7,8-tetramethylchroman -2-yl] ethanol­precursor of natural α-tocols].

A novel promising strain of actinobacteria Rhodococcus sp. 77-32 was identified. Its acetonetreated biomass the could be used as a biocatalyst for production of S-(-)-2-[6-benzyloxy-2,5,7,8-tetramethylchroman-2-yl] ethanol (S-BCE), a precursor of natural α-tocols. It was established that a reaction of enantioselective hydrolysis of racemic (±)-2-(2-acetoxyethyl)-6-benzyloxy-2,5,7,8-tetramethylchroman (BCEA) occurred in the phosphate buffer­acetone system, resulting in enrichment of the residual substrate by S-enantiomer (S-(+)-2-(2-acetoxyethyl)-6-benzyloxy-2,5,7,8-tetramethylchroman, S-BCEA). It was shown that the hydrolysis was accompanied by stereoinversion of the formed product, R-(+)-2-[6-benzyloxy-2,5,7,8-tetramethylchroman-2-yl] ethanol (R-BCE), into the S-BCE. The transformation conditions (acetone content, acidity, temperature, reaction duration) were optimized, providing simultaneous production of optically pure S-BCE and S-BCEA with an almost quantitative yield.

pH-Dependent Changes in the Mechanisms of Transport of Chlorine e6 and Its Derivatives in the Blood.

We studied the effects of medium pH on steady-state distribution of chlorine e6 and its derivatives between the main transport proteins of human blood plasma. The decrease in medium pH from weakly alkaline (pH 7.4) to acid (pH 5.0) was followed by an increase in relative affinity of chlorines to lipoproteins and reduced their affinity to serum albumin. pH-Dependent changes in the parameters of distribution of photosensitizers between the plasma and blood cells was revealed. We discussed the role of charge and polarity degree of photosensitizer molecule in the mechanism of binding to serum albumin. A possible role of changes in hydrogen ion activity in the processes of selective accumulation of chlorines by tumor cells is discussed.

[Prospects for the use of cells possessing myogenic potential in the treatment of skeletal muscle diseases: a review of research. Part 1 - satellite cells].

Musculoskeletal functions disorders may develop as a consequence of injuries and various types of congenital / acquired diseases, among which a special place belongs to muscular dystrophy. The technology with use of cells possessing myogenic potential is considered as one of the most promising approaches to solve the problem of effective restoration of skeletal muscles structure and function. In part I of the article the characteristic features, functions and phenotypic characteristics of satellite cells (SC) are reviewed as key factors of skeletal muscle tissue regeneration. Presented analysis of research results (preclinical and clinical) concerning therapeutic possibilities of technology using SC. In the second part of review will be presented data of the therapeutic use of stem cells of muscle and non-muscle origin for the treatment of skeletal muscles diseases.

[Searching Radiation Countermeasures using the Model of Prolonged Irradiation of Mice with Low Dose Rate and Evaluation of Their Influence on Heat Shock Protein Genes Expression].

Different radiomodificators (cytokine betaleukine, antioxidant phenoxan, antigipoksant limontar and nucleoside riboxin) were investigated on mice for evaluating their radiation protective capacity against prolonged (21 h) exposure at a dose of 12.6 Gy at a low dose rate of 10 mGy/min. Bone marrow cellularity and endogenic CFUs were used as evaluation criteria 9 days after exposure. Simultaneously, expression of the heat shock proteins of 25, 70 and 90 kDa in unexposed mice bone marrow was studied 2, 24 and 48 h after injections. Betaleukine only had a positive significant effect in both tests in the variants of 50 mcg/kg and 3 mcg/kg when administered 2 h and 22 h before exposure, correspondingly. Effects of betaleukine HSPs on expression were both stimulating and inhibiting, that was in contradiction with a constant positive effect in 5 experiments on exposed mice for each betaleukine variant. It argues against the vital role of HSPs in the betaleukine antiradiation effect. In 2 experiments with high temperatures betaleukine administered at a dose of 50 mcg/kg evoked a very high HSP-70 gene expression after 24 h, and mice exposed to irradiation at that time in a parallel experiment showed an increased radiation effect. It corresponds to the idea that HSPs serve a stress indicator.

[Evaluation of Photo- and Cytotoxicity of Chlorin e6 Ester Derivatives and Their Liposomal Forms].

Photophysical characteristics and photosensitizing activity of the chlorin e6 dimethyl and trimethyl ester derivatives in various solution and their liposomal forms were studied. It was shown that in lipid vesicles chlorin e6 ester derivatives are predominantly in the monomeric state and possess optimal photophysical properties and high photochemical activity. The rate of redistribution of the chlorin e6 dimethyl ester from lipid vesicle to cells was higher as compared with that one of the chlorin e6 trimethyl ester. The increase of the serum concentration in the incubation medium has a different effect on processes of accumulation of the liposomal forms of the chlorin e6 dimethyl and trimethyl ester derivatives by the cells. Cell culture studies showed that application of liposomal forms of the chlorin e6 dimethyl and trimethyl ester derivatives significantly decreases their cytotoxicity but keeps high cytotoxic effect of photodynamic activity of the chlorin e6 ester derivatives.

[Prospects for the Use of Cells Possessing Myogenic Potential in the Treatment of Skeletal Muscle Diseases: a Review of Research. Part 2--Populations of stem cells of muscle and non-muscle origin].

The paper reviews research results of myogenic potential, specific properties, functions, and phenotypic features of a number of stem cells populations of muscle and non-muscle origin, their ability to participate in the restoration of the physiological homeostasis of skeletal muscle. The results of scientific research allow to predict with high probability the establishment of an effective cell technology to treat degenerative muscle diseases.

Emittance of short-pulsed high-current ion beams formed from the plasma of the electron cyclotron resonance discharge sustained by high-power millimeter-wave gyrotron radiation.

We present experimental results on measuring the emittance of short-pulsed (≤100 µs) high-current (80-100 mA) ion beams of heavy gases (Nitrogen, Argon) formed from a dense plasma of an ECR source of multiply charged ions (MCI) with quasi-gas-dynamic mode of plasma confinement in a magnetic trap of simple mirror configuration. The discharge was created by a high-power (90 kW) pulsed radiation of a 37.5-GHz gyrotron. The normalized emittance of generated ion beams of 100 mA current was (1.2-1.3) π mm mrad (70% of ions in the beams). Comparing these results with those obtained using a cusp magnetic trap, it was concluded that the structure of the trap magnetic field lines does not exert a decisive influence on the emittance of ion beams in the gas-dynamic ECR source of MCI.

[Influence of indoinetophene on the antiradiation properties of indralin].

Radioprotective properties of indralin were studied at its combined administration with indometophene in the periods optimal for each preparation before acute radiation exposure. Animals were subjected to total radiation on the IGUR installation (137Cs): mice of the strain (CBA x C57B1) F1 at a dose of 9 Gy (LD100/30), purebred dogs--4 Gy (LD100/45). It was established in the experiments on mice that considerable radioprotective effect can be obtained by the use of indralin at a dose that is half the optimal radioprotective dose if it is applied against the background of indometophene administered at its optimal radioprotective dose four days before. The survival of mice increased on the average by 30-35% and provided the same effect of protection as a single indralin at the optimal radioprotective dose (100 mg/kg). The survivability of dogs after the combined application of the two radioprotectors makes up 43% against 14% after application of only indralin at a dose of 5 mg/kg (half the optimal radioprotective dose). Indometophene, along with strengthening the antiradiation activity of indralin at the ineffective (half the optimal) dose, allows the reduction of its undesirable postradiation effects in the hemopoietic tissue. The important role in the mechanism of the antiradiation activity of indometophene and indralin belongs to the increased ribonucleotide reductase activity and induction of the ribonucleotide synthesis that provides effective reparation of the damage to the DNA of the cells in radiosensitive tissues and organs as a result of administration of protective doses of radioprotectors at the optimal doses before radiation exposure.

[Autofibroblasts in surgical treatment of periodontal disease].

Effectiveness of periodontal disease surgical treatment using hydroxyapatite with gingival autofibroblasts culture was assessed in the study by clinical and laboratory data.

[Evaluation of the treatment effectiveness of domestic G-SCF preparations in experiments on irradiated dogs].

We have evaluated the treatment effectiveness of Leucostim and Neupomax in dogs exposed to radiation at lethal doses of 3 and 3.5 Gy, correspondingly, by testing the dynamics of the blood cell number, first of all, leucocytes and neutrophiles, and the 45-day survival. Supportive therapy for all the dogs, including the control ones, consisted in antibiotic treatment during the acute period of 7-24 days. It was shown that both pre-parations administered consecutively for about 17-21 days after irradiation positively influenced the dynamics of all blood cells but predominantly impacted the neutrophile number dynamics. The latter ones manifested a higher nadir level and an earlier onset of restoration in the G-SCF treated dogs in comparison with the control ones. The tendency to a positive influence on the survival has been shown in Neupomax-treated dogs exposed to 3.5 Gy of radiation (plus about 40%). The results of the experiments were in good accordance with the data by foreign authors who used Neupogen. This allows a conclusion that home-produced G-SCF preparations can replace their foreign analogues.

[Use of autogenous fibroblasts of human oral mucosa for gum recession treatment].

Minimally invasive soft tissue augmentation is a challenging problem for dentists. Use of autogenous fibroblast of oral mucosa is a promising method. The paper represents the results of preclinical, clinical and laboratory studies on the use of autogenous oral mucosa fibroblasts (AOMF) for gum recession correction. The results confirm statistically significant gum thickness augmentation and gum recession decrease after three weekly AOMF injections. The effect lasted for at least 9 months.

[Recombinant thrombopoietin antiradiation therapeutic effectiveness evaluation on dogs according to hemopoiesis and survival criteria].

Recombinant human thrombopoietin (rh TPO) has been investigated as a means of acute radiation disease urgent treatment in the experiments on 24 mongrel dogs. The animals were exposed to total acute gamma-irradiation at the doses of 3.5 Gy (exceeding LD50/45 under our conditions) and 3 Gy. All the dogs including control ones received antibiotics Ampicillin and Gentamicin twice a day during the acute period from the 7th to the 21st day. TPO was injected one time s/c or i/v at the doses of5 or 10 mkg/kg 1.5-2 h after exposure. TPO at a dose of 5 mkg/kg was ineffective. TPO at a dose of 10 mkg/kg had a positive effect on the kinetics of blood forming units, especially platelets (nadir, restoration rate) in terms of the 45-day survival. As a result, in TPO groups, nadir averaged at both exposure doses on leucocytes (1.3-1.4) x 10(9)/l vs (0.70-0.75) x 10(9)/l in control groups and on thrombocytes (102-112) x 10(9)/l vs (44-33) x 10(9)/l in control ones. Despite the low number of animals in experimental groups, the results permit to regard rhTPO as a worth-while urgent therapeutic means for the acute radiation damage treatment and preventing thrombopenia.

Influence of the shear flow on electron cyclotron resonance plasma confinement in an axisymmetric magnetic mirror trap of the electron cyclotron resonance ion source.

Influence of shear flows of the dense plasma created under conditions of the electron cyclotron resonance (ECR) gas breakdown on the plasma confinement in the axisymmetric mirror trap ("vortex" confinement) was studied experimentally and theoretically. A limiter with bias potential was set inside the mirror trap for plasma rotation. The limiter construction and the optimal value of the potential were chosen according to the results of the preliminary theoretical analysis. This method of "vortex" confinement realization in an axisymmetric mirror trap for non-equilibrium heavy-ion plasmas seems to be promising for creation of ECR multicharged ion sources with high magnetic fields, more than 1 T.

Optimization of gas utilization efficiency for short-pulsed electron cyclotron resonance ion source.

Numerical analysis of (6)He atoms utilizing efficiency in the ion source with powerful gyrotron heating is performed in present work using zero-dimensional balanced model of ECR discharge in a magnetic trap. Two ways of creation of ion source with high gas utilization efficiency (up to 60%-90%) are suggested.

[Stem cells technologies in the treatment of burns].

Effective treatment of bums is one of effective in present medicine. Using cellular technology is one of the perspective directions for restoration of the integrity of the skin after burn injury an overview of the commercial preparations, presented at the European and American markets, and technologies developed by leading institutions in Russia.

High-voltage pulsed generator for dynamic fragmentation of rocks.

A portable high-voltage (HV) pulsed generator has been designed for rock fragmentation experiments. The generator can be used also for other technological applications. The installation consists of low voltage block, HV block, coaxial transmission line, fragmentation chamber, and control system block. Low voltage block of the generator, consisting of a primary capacitor bank (300 µF) and a thyristor switch, stores pulse energy and transfers it to the HV block. The primary capacitor bank stores energy of 600 J at the maximum charging voltage of 2 kV. HV block includes HV pulsed step up transformer, HV capacitive storage, and two electrode gas switch. The following technical parameters of the generator were achieved: output voltage up to 300 kV, voltage rise time of ∼50 ns, current amplitude of ∼6 kA with the 40 Ω active load, and ∼20 kA in a rock fragmentation regime (with discharge in a rock-water mixture). Typical operation regime is a burst of 1000 pulses with a frequency of 10 Hz. The operation process can be controlled within a wide range of parameters. The entire installation (generator, transmission line, treatment chamber, and measuring probes) is designed like a continuous Faraday's cage (complete shielding) to exclude external electromagnetic perturbations.

A compact submicrosecond, high current generator.

Pulsed current generator was developed for experiments with current carrying pulsed plasma. Main parts of the generator are capacitor bank, low inductive current driving lines, and central load part. Generator consists of four identical sections, connected in parallel to one load. Capacitor bank is assembled from 24 capacitor blocks (100 kV, 80 nF), connected in parallel. It stores 9.6 kJ at 100 kV charging voltage. Each capacitor block incorporates a multigap spark switch, which is able to commute by six parallel channels. Switches operate in dry air at atmospheric pressure. The generator was tested with an inductive load and a liner load. At 17.5 nH inductive load and 100 kV of charging voltage it provides 650 kA of current amplitude with 390 ns rise time with 0.6 ohms damping resistors in discharge circuit of each capacitor block. The net generator inductance without a load was optimized to be as low as 15 nH, which results in extremely low impedance of the generator (approximately 0.08 ohms). It ensures effective energy coupling with a low impedance load such as Z pinch. The generator operates reliably without any adjustments in 70-100 kV range of charging voltage. Jitter in delay between output pulse and triggering pulse is less than 5 ns at 70-100 kV charging voltage. Operation and handling are very simple, because no oil or purified gases are required for the generator. The generator has dimensions 5.24x1.2x0.18 m(3) and total weight about 1400 kg, thus manifesting itself as simple, robust, and cost effective apparatus.

Three-electrode gas switches with electrodynamical acceleration of a discharge channel.

High voltage, high current, and high Coulomb transfer closing switches are required for many high power pulsed systems. There are a few alternatives for closing switches, for example, ignitrons, vacuum switches, solid-state switches, high pressure gas switches (spark gaps), and some others. The most popular closing switches up to date are spark gaps due to relatively simple design, robustness, easily field maintenance, and repair. Main drawback of spark gaps is limited lifetime, which is related directly or indirectly to erosion of the electrodes. Multichannel switches and switches with moving arc have been proposed to prevent the electrodes erosion. This study investigates switches, where a spark channel is initiated in a three-electrode layout and then the spark accelerates due to electrodynamic force and moves along the extended electrodes. At a given current amplitude, the diameter of the extended electrodes allows to control the spark velocity and hence, the erosion of the electrodes providing the required lifetime. The first switch is designed for 24 kV charging voltage and approximately 4 C total charge transfer. This spark gap was tested at 25 kA peak current in 40 000 shots in a single polarity discharge and in 20 000 shots in bipolar discharge. Second spark gap is designed for 24 kV charging voltage and approximately 70 C total charge transfer. It was tested in 22 000 shots, at a current of 250 kA with a pulse length of 360 mus. In this paper, we present design of these spark gaps and trigger generator, describe the test bed, and present the results of the tests.