Synergistic Interaction of Environmental Temperature and Microwaves: Prediction and Optimization

Vladislav G. Petin,Jin Kyu Kim,Olga I. Kolganova,Leonid P. Zhavoronkov 대한방사선방어학회 2011 방사선방어학회지 Vol.36 No.1

Yeast cells retain a memory of their original radiation-induced insults

Petin, Vladislav G,Pereklad, Olga V,Nili, Mohammad,Kim, Jin Kyu 한국방사선산업학회 2008 방사선산업학회지 Vol.2 No.2

Cell Ploidy and Repair Ability Determine the Radioprotective Effects of Cysteamine in Yeast Cells of Various Species and Genotypes

(Vladislav G. Petin),(Jin Kyu Kim) 한국환경생물학회 2002 환경생물 : 환경생물학회지 Vol.20 No.1

N/A The significance of cell ploidy and repair ability for the radioprotective efficiency of cysteamine was studied in DNA repair-proficient and repair-deficient yeast cells irradiated with ^60Co γ-rays. Results have been obtained for the cell survival of two groups of yeasts-diplont and haplont cells, both in haploid and diploid states. For diploid Saccharomyces cerevisiae yeast cells, the correlation between the radio-protective action of cysteamine and the cell repair capacity was demonstrated. Such a correlation was not clearly expressed for haploid yeast cells. In addition, evidence was obtained indicating that the degree of the radioprotective action was independent of the number of chromosome sets in haplont yeast Pichia guilliermondii cells and in some radiosensitive mutants defective in the diploid-specific recovery. It is concluded on this basis that the radioprotective action may involve the cellular recovery process, which may be mediated by a recombination-like mechanism, for which the diploid state is required. The results obtained clearly show that the radioprotective effect was dependent on DNA repair status and indicate that the mechanism of the radioprotective action may be realized on the level of primary radiation damage production as well as on the level of postradiation recovery from potentially lethal radiation damage.

SYNERGISTIC INTERACTION OF ENVIRONMENTAL TEMPERATURE AND MICROWAVES: PREDICTION AND OPTIMIZATION

Petin, Vladislav G.,Kim, Jin-Kyu,Kolganova, Olga I.,Zhavoronkov, Leonid P. The Korean Association for Radiation Protection 2011 방사선방어학회지 Vol.36 No.1

A simple mathematical model of simultaneous combined action of environmental agents has been proposed to describe the synergistic interaction of microwave and high ambient temperature treatment on animal heating. The model suggests that the synergism is caused by the additional effective damage arising from an interaction of sublesions induced by each agent. These sublesions are considered to be ineffective if each agent is taken individually. The additional damage results in a higher body temperature increment when compared with that expected for an independent action of each agent. The model was adjusted to describe the synergistic interaction, to determine its greatest value and the condition under which it can be achieved. The prediction of the model was shown to be consistent with experimental data on rabbit heating. The model appears to be appropriate and the conclusions are valid.

Liquid holding recovery kinetics in wild-type and radiosensitive mutants of the yeast <i>Saccharomyces</i> exposed to low- and high-LET radiations

Petin, Vladislav G.,Kim, Jin Kyu Elsevier 2005 Mutation research Vol.570 No.1

<P><B>Abstract</B></P><P>Three wild-type diploid yeast strains <I>Saccharomyces ellipsoideus</I> and <I>Saccharomyces cerevisiae</I> and five radiosensitive mutants of <I>S. cerevisiae</I> in the diploid state were irradiated with γ-rays from <SUP>60</SUP>Co and α-particles from <SUP>239</SUP>Pu in the stationary phase of growth. Survival curves and the kinetics of the liquid holding recovery were measured. It was shown that the irreversible component was enhanced for the densely ionizing radiation in comparison to the low-LET radiation while the probability of the recovery was identical for both the low- and high-LET radiations for all the strains investigated. It means that the recovery process itself is not damaged after densely ionizing radiation and the enhanced RBE of the high-LET radiation may be caused by the increased yield of the irreversible damage. A parent diploid strain and all its radiosensitive mutants showed the same probability for recovery from radiation damage. Thus, the mechanism of the enhanced radiosensitivity of the mutant cells might not be related to the damage of the repair systems themselves but with the production of some kind of radiation damage from which cells are incapable to recover.</P>

Mathematical Interpretation of Cell Lethality by Sequential Actions of Ionizing Radiation and Hyperthermia

Jin Kyu KIM,Vladislav G. PETIN,Remigius A. KAWALA,Jin-Hong KIM 한국생물공학회 2015 한국생물공학회 학술대회 Vol.2015 No.10

Theoretical Conception of Synergistic Interactions

Kim, Jin Kyu,Petin, Vladislav G. 한국환경생물학회 2002 환경생물 : 환경생물학회지 Vol.20 No.4

An increase in the overall biological effect under the combined action of ionizing radiation with another inactivating agent can be explained in two ways. One is the supposition that synergism may attribute to a reduced cellular capacity of damage repair after the combined action. The other is the hypothesis that synergism may be related to an additional lethal or potentially lethal damage that arises from the interaction of sublesions induced by both agents. These sublesions are considered to be in-effective when each agent is applied separately. Based on this hypothesis, a simple mathematical model was established. The model can predict the greatest value of the synergistic effect, and the dependence of synergy on the intensity of agents applied, as well. This paper deals with the model validation and the peculiarity of simultaneous action of various factors with radiation on biological systems such as bacteriophage, bacterial spores, yeast and mammalian cells. The common rules of the synergism are as follows. (1) For any constant rate of exposure, the synergy can be observed only within a certain temperature range. The temperature range which synergistically increases the effects of radiation is shifted to the lower temperature for thermosensitive objects. Inside this range, there is a specific temperature that maximizes the synergistic effect. (2) A decrease in the exposure rate results in a decrease of this specific temperature to achieve the greatest synergy and vice versa. For a constant temperature at which the irradiation occurs, synergy can be observed within a certain dose rate range. Inside this range an optimal intensity of the physical agent may be indicated, which maximizes the synergy. As the exposure temperature reduces, the optimal intensity decreases and vice versa. (3) The recovery rate after combined action is decelerated due to an increased number of irreversible damages. The probability of recovery is independent of the exposure temperature for yeast cells irradiated with ionizing or UV radiation. Chemical inhibitors of cell recovery act through the formation of irreversible damage but not via damaging the recovery process itself.

Chemical Inhibition of Cell Recovery after Irradiation with Sparsely and Densely Ionizing Radiation

Ekaterina S. Evstratova,김진홍,임영기,김진규,Vladislav G. Petin (사)한국방사선산업학회 2016 방사선산업학회지 Vol.10 No.4

The dependence of cell survival on exposure dose and the duration of the liquidholding recovery (LHR) was obtained for diploid yeast cells irradiated with ionizing radiation of different linear energy transfer (LET) and recovering from radiation damage without and with various concentrations of cisplatin - the most widely used anticancer drug. The ability of yeast cells to recover from radiation damage was less effective after cell exposure to high-LET radiation, when cells were irradiated without drug. The increase in cisplatin concentration resulted in the disappearance of this difference whereas the fraction of irreversible damage was permanently enlarged independently of radiation quality. The probability of cell recovery was shown to be constant for various conditions of irradiation and recovery. A new mechanism of cisplatin action was suggested according with which the inhibition of cell recovery after exposure to ionizing radiations was completely explained by the production of irreversible damage.

온도와 물리화학적 환경요인에 의한 상승작용의 규칙성에 관한 실험적 고찰

김진규,신해식,블라디슬라프페틴,이영엽 한국환경생물학회 2002 환경생물 : 환경생물학회지 Vol.20 No.2

두가지 유해인자가 동시에 작용할 때 생물체에 나타나는 영향을 길항작용에서 상승작용에 이르기까지 폭넓게 나타난다. 상승작용의 생물학적 중요성에도 불구하고 유해인자간의 복합작용을 설명할 수 있는 구체적 연구결과들은 별로 없는 실정이다. 본 연구는 고온과 기타환경 유해인자의 복합작용에 의해 생물체에 나타내는 반응에 있어서의 규칙성을 도출해 내기 위하여 수행되었다. 고온과 이온화방사선, 자외선, 초음파 등의 동시작용에 관한 효모세포 실험결과를 분석하였으며 다른 연구자들에 의하여 수행된 바이러스, 세균포자, 동식물세포 및 포유류 배양세포에 관한 실험결과를 이용하여 도출된 규칙성을 검증하였다. 본 연구를 통하여 검증된 상승작용에 관한 규칙성은 다음과 같이 요약될 수 있다. 방사선량률이 일정할 경우 특정 온도범위 내에서만 상승작용을 관찰할 수 있다. 방사선량률을 증가시키면 최대 상승작용을 나타내는 온도 값도 증가하게 되며, 선량률을 낮추면 온도가 일정할 경우 특정범위의 선량률에서만 상승작용이 관찰되는데, 이 범위 내에 최대상승작용 유발 선량률 값이 존재한다. 방사선 조사시의 온도를 낮추면 선량률의 값 또한 낮아지며 그 역도 마찬가지이다. 본 연구에서 밝혀진 규칙성은 상승작용의 신개념 적립에 실마리를 제공할 것이며 특히 생물체에 대한 유해 환경 요인의 복합영향 해석과 환경재해 예방을 위한 영향평가 및 위해 평가에 유용하게 활용될 수 있을것이다. The combined action of two factors on organisms can be either antagonistic, non-effective, additive or synergistic. Although synergism is of biological importance, the common features of synergistic interaction between harmful environmental factors are largely unknown. The purpose of this study is to establish general rules describing the response of various organisms to the combined action of heat with another inactivating agent. Synergistic interaction due to the simultaneous treatment of hyperthermia with ionizing or non-ionizing radiation has been analyzed using the experimental data mainly obtained with yeast cells. In addition, the results reported by others for viruses, bacterial spores, cultured mammalian cells, plants and animals were also analyzed to check the regularities revealed. The common rules of the synergistic interaction obtained in this study can be summarized as follows. For any constant rate of exposure, the synergy can be observed only within a certain temperature range. An increase in exposure rate resulted in an increase of this specific temperature and vice versa. For a constant temperature at which the irradiation occurs, synergy can be observed within a certain dose rate range. As the exposure temperature is reduced, the optimal intensity decreases and vice versa. A new conception taken into consideration those regularities can make a clue for environmental disaster preventive analysis of the synergy of radiation with the other factor.

Mathematical Description and Prognosis of Cell Recovery after Thermoradiation Action

Komarova Ludmila N.,Kim Jin-Kyu,Petin Vladislav G. 한국환경생물학회 2008 환경생물 : 환경생물학회지 Vol.26 No.1