Biological Response of Chinese Hamster B14-150 Cells to Sequential Combined Exposure to Protons and 12C Ions.

Proton and ion radiation therapy, when used both as single radiation and in mixed radiation mode, have a number of advantages over the conventional γ-therapy that are determined by physical characteristics of accelerated particles. The paper presents the results of an in vitro study of the effectiveness of sequential exposures of Chinese hamster tumor cells B14-150 to proton (p) and 12C ion beams. We used 4 irradiation schemes differing by the sequence of exposure and the contribution of each radiation to the total dose. Synergism was shown for 12C ions dose contribution of 45% (taking into account the coefficient of relative biological efficiency) and the sequence 12C→p.

Effects of Combined Exposure to Carbon Ions and Protons on the Pool of MCF-7 Breast Cancer Stem Cells In Vitro.

We studied the effects of single and combined action of protons and carbon ions 12C6+ on the pool of MCF-7 human breast cancer stem cells. Single irradiation with a beam of protons or carbon ions had no significant effects on the relative number of cancer stem cells (CSC). The effects of combined irradiation in a total equieffective dose of 4 Gy depended on the sequence of exposure to ionizing radiations: the relative number of CSC did not change after irradiation with carbon ions and then with protons, but increased in the case of the reverse sequence. The most favorable result, i.e. a decrease in the CSC pool, was observed in the case of sequential irradiation with carbon ions and protons and their equal contribution to total equieffective dose. In this case, the absolute number of CSC decreased by on average 2.1 times in comparison with the control (p<0.05). The revealed regularities are of interest for the further development of new methods of radiation therapy.

Post-Irradiation Recovery of B14-150 Fibrosarcoma Cells after Combined Irradiation with Low and High Linear Energy Transfer.

The use of radiation with low and high linear energy transfer (LET) in the same treatment regimen is promising in terms of increasing the efficiency and reducing the severity of radiation complications. Here we studied combined effect of protons (LET≈3 keV/µm) and heavy recoils (HR) induced by 14.5 MeV neutrons (LET≈290 keV/µm) on B14-150 fibrosarcoma cells. Comparison of the 4 irradiation schemes with different high-LET/low-LET dose ratios and the irradiation sequences revealed higher effectiveness of the combined action in the HR→protons sequence and with increasing HR dose contribution to 40% of the total dose. The observed effects were due to differences in the recovery of damages induced in cells by radiations with low and high LET.

Calculation of the Biological Efficiency of the Proton Component from 14.8 MeV Neutron Irradiation in Computational Biology with Help of Video Cards.

Fast neutron therapy, which previously has demonstrated effective results, but along with a large number of complications, can again be considered a promising treatment method in the treatment of cancer. One of the ways of analyzing the relative biological efficiency and accurate biological dose of fast neutrons in body tissues is to improve the algorithms of computational biology and mathematical modeling. A high-performance computing code was written which allows to estimate in real-time mode the biological dose of the proton component from the action of neutron radiation with an energy of 14.8 MeV. A comparative analysis of the computing performance on various video cards was also performed.

[Breeding dynamic of corvids in urbanized landscapes of the European east].

On the basis of counting and mapping of nests of the rook, hooded crow, and magpie in Kirov in 1975-2012, it was found that, under the conditions of an industrial city, rook colonies are highly unstable. The elimination of the private sector and neglected tree and scrub thickets leads to a reduction in the number of magpies nesting in the city. The nesting abundance of crows is limited by the quarter layout and placement of containers for household waste.

[The system of readiness to take care of medical consequences in disaster situations]. / Sistema predvaritel'noi gotovnosti k likvidatsii meditsinskikh posledstvii chrezvychainykh situatsii.

The main task of regional catastrophe medicine service in liquidation of medical consequences of emergency situations is the immediate adequate reaction which is aimed at minimizing the sanitary loss. This task can be effectively solved only on condition of permanent improvement of interaction between the managing and managed systems of public health and coordination of their actions with those of nonmedical services. An important role is played by the actualized (constantly renewed) data bases "Potentially Hazardous Objects", "Regional Infrastructure", "Medicosanitary Means", etc., which help simulate various emergency situations with due consideration for the season, time of the day, and socioeconomic features of a region in order to create variants of effective work of all services engaged in the liquidation of medical consequences.

[Arousal thresholds during stimulation of brain structures in nonanesthetized cats]. / Porogi reaktsii aktivatsii pri razdrazhenii raznykh struktur mozga u nenarkotizirovannoi

In cats, there was no apparent difference between the average low thresholds for evoking EEG arousal when stimulating the mesencephalic RF, thalamic CM or some cortical structures (sensorimotor area, inferior part of auditory Ep). Most of other cortical points had much higher thresholds (g. lateralis anterior, g. suprasylvius posterior, g. ectosylvius med. and sup.). The possible role of some cortical and mesencephalic structures in the brain activating mechanisms is discussed.