CYTOGENETIC STUDY OF MANIFESTATIONS OF THE UNIVERSAL PHENOMENON OF THE BYSTANDER RESPONSE. / TsYTOGENETYChNE DOSLIDZhENNIa PROIaVIV UNIVERSAL'NOGO IaVYShchA EFEKTU SVIDKA.

OBJECTIVE: to establish the level of chromosomal instability in peripheral blood lymphocytes (PBL) from healthyindividuals and cells from patients with B-cell chronic lymphocytic leukemia (CLL) under co-cultivation conditions and to determine the possibility of inducing manifestations of the universal phenomenon of bystander response in them. MATERIALS AND METHODS: Cytogenetic analysis of uniformly stained chromosomes from human PBL, which differed by cytogenetic markers of sex; the presence of oncological transformation and in vitro irradiation of 137Cs in a dose of 0.50 Gy under the conditions of their joint cultivation was performed. RESULTS: The frequency of chromosome aberrations in PBL from healthy individuals when co-cultured with the blood from CLL patients was 3.35 per 100 cells, exceeded the control (1.48 per 100 cells, р < 0.01), did not significantly differ from the rate in non-irradiated blood T-lymphocytes from patients with B-cell CLL (3.18 per 100 cells, р > 0.05) and was lower than when co-cultivated with irradiated blood from CLL patients (5.00 per 100 cells, р < 0.01). In irradiated in vitro blood lymphocytes from CLL patients, the mean group level of chromosome aberrations under separate cultivation was 12.36 per 100 cells and exceeded the indicator during their co-cultivation with lymphocytes from healthy individuals (8.35 per 100 cells, р < 0.05). CONCLUSIONS: A tumor-induced bystander effect (TIBE) develops in PBL from healthy individuals when co-cultured with the blood from CLL patients and in T lymphocytes of B-cell CLL patients, the cytogenetic manifestation of which is an increase in the frequency of single chromatid fragments. The interaction of irradiated blood cells from CLL patients with lymphocytes from healthy individuals causes an increase in chromosomal instability in the latter due to the development of a radiation-induced bystander effect (RIBE) and leads to a decrease in the level of chromosomal instability in irradiated lymphocytes from CLL patients (rescue effect). An increase in the level of chromatid-type aberrations in T-lymphocytes of CLL patients during in vitro irradiation is a consequence of the development of RIBE against the background of TIBE.

Study of modifying effects of astaxanthin on cytogenetic manifestations of bystander response in human peripheral blood lymphocytes in vitro.

AIM: To study the possible impact of astaxanthin on the cytogenetic manifestations of the simultaneous development of radiation-induced (RIBE) and tumor-induced bystander effect (TIBE) in human peripheral blood lymphocytes. MATERIALS AND METHODS: Peripheral blood lymphocytes from healthy persons and patients with chronic lymphocytic leukemia were cultured separately or cocultured with or without previous irradiation in vitro by 137Cs at a dose of 0.5 Gy. The cells were cultured with and without 20 µg/ml astaxanthin. RESULTS: In the presence of astaxanthin, the decrease of chromosomal instability both in the variant with separate TIBE and with simultaneous development of TIBE and RIBE was observed as the reduction in the frequency of simple chromosome-type aberrations, namely, double fragments. The average level of chromatid-type aberrations did not change under the action of astaxanthin. Although the total chromosome instability in bystander cells diminished, this did not lead to the elimination of the RIBE and TIBE development in the presence of astaxanthin. CONCLUSION: In the setting of experiment, astaxanthin did not reduce the frequency of chromatid-type aberrations in bystander cells due to RIBE and TIBE but reduced the frequency of simple aberrations of chromosomal type, not associated with the development of bystander response phenomenon.

STUDY THE EFFECTS OF IONIZING RADIATION ON THE LEVEL OF CHROMOSOME INSTABILITY IN HUMAN SOMATIC CELLS DURING THE DEVELOPMENT OF TUMOR-INDUCED BYSTANDER EFFECT. / DOSLIDZhENNIa VPLYVU IONIZUIuChOÏ RADIATsIÏ NA RIVEN' KhROMOSOMNOÏ NESTABIL'NOSTI V SOMATYChNYKh KLITYNAKh LIuDYNY PRY ROZVYTKU PUKhLYNO-INDUKOVANOGO EFEKTU SVIDKA.

OBJECTIVE: to determine the impact of the irradiated in vitro blood cells from patients with B-cell chronic lymphocytic leukemia (CLL) on the level of chromosomal instability in peripheral blood lymphocytes (PBL) from healthy persons during the development of tumor-induced bystander effect. MATERIALS AND METHODS: Separate and joint cultivation of PBL from healthy persons (cells-bystanders) together withblood cells from CLL patients irradiated in vitro at the G0 stage of the mitotic cycle by γ-quanta 137Cs in a dose of0.5 Gy 137Cs (cells-inductors) was used. For joint cultivation our own model system for co-cultivation of PBL fromindividuals of different sex, designed by us to investigate the bystander effects at the cytogenetic level was used.Traditional cytogenetic analysis of uniformly painted chromosomes with group karyotyping was performed. The frequency of chromosome aberrations in cells-inductors and cells-bystanders as the markers of chromosome instability were determined. RESULTS: Found that at co-cultivation of PBL from healthy individuals with irradiated blood cells from CLL patientsthe middle group frequency of chromosome aberrations in the bystander cells (5.18 ± 0.51 per 100 metaphases,p < 0.001) was statistically significant higher than its background level determined at a separate cultivaton (1.52± 0.30 per 100 metaphases), and at co-cultivation with non-irradiated blood cells from CLL patients (3.31 ± 0.50 per100 metaphases, p < 0.01). CONCLUSIONS: Co-cultivation of in vitro irradiated blood cells from CLL patients with PBL from healthy persons leadsto an increase in the level of chromosome instability in the bystander cells due to synergism between tumor-inducedand radiation-induced bystander effects.

RADIATION-INDUCED BYSTANDER EFFECT - MODELING, MANIFESTATION, MECHANISMS, PERSISTENCE, CANCER RISKS (literature review). / RADIATsIY̆NO-INDUKOVANYY̆ EFEKT SVIDKA ­ MODELIuVANNIa, PROIaVY, MEKhANIZMY ROZVYTKU, PERSYSTENTsIIa, ONKOLOGIChNI RYZYKY (ogliad literatury).

The review summarizes and analyzes the data of world scientific literature and the results of the own research con- cerning one of the main non-targeted effects of ionizing radiation - the radiation induced bystander effect (RIBE) - the ability of irradiated target cells to induce secondary biological changes in non-irradiated receptor cells. The his- tory of studies of this phenomenon is presented - it described under various names since 1905, began to study from the end of the twentieth century when named as RIBE and caused particular interest in the scientific community during recent decades. It is shown that the development of biological science and the improvement of research methods allowed to get new in-depth data on the development of RIBE not only at the level of the whole organism, but even at the genome level. The review highlights the key points of numerous RIBE investigations including mod- eling; methodological approaches to studying; classification; features of interaction between irradiated and intact cells; the role of the immune system, oxidative stress, cytogenetic disorders, changes in gene expression in the mechanism of development of RIBE; rescue effect, abscopal effect, persistence, modification, medical effects. It is emphasized that despite the considerable amount of research concerning the bystander response as the universal phenomenon and RIBE as one of its manifestations, there are still enough «white spots¼ in determining the mech- anisms of the RIBE formation and assessing the possible consequences of its development for human health.

DEVELOPMENT OF RADIATION-INDUCED BYSTANDER EFFECT IN THE SOMATIC CELLS OF PERSONS FROM DIFFERENT AGE GROUPS. / ROZVYTOK RADIATsIINO-INDUKOVANOGO EFEKTU SVIDKA V SOMATYChNYKh KLITYNAKh OSIB RIZNOGO VIKU.

OBJECTIVE: To investigate the development of chromosomal instability as a result of the radiation-induced bystandereffect in blood lymphocytes of persons from different age groups. MATERIALS AND METHODS: Materials of research were blood lymphocytes from 42 persons of different age (from 12 to102 years), divided into four age groups - teenagers, middle-aged, elderly and centenarians. Bystander effect wasstudied by modeling its induction in human lymphocytes, at which 0.3 ml of non-irradiated blood (served asbystander cells) and 0.3 ml of blood from persons of another sex exposed in vitro to X-ray in a dose of 0.25 Gy wereadded to the incubation mixture, followed by cultivation according to generally accepted semi-micro-method. Slidesof metaphase chromosomes were GTG-stained and analyzed under light microscopes with magnification x 1000. RESULTS: The average level of chromosomal aberrations in bystander cells of teenagers (6.08 ± 0.67 per 100metaphases), middle-aged people (4.56 ± 0.61 per 100 metaphases) and elderly persons (6.34 ± 0.76 per 100metaphases) significantly exceeded those of the corresponding age-related controls (p <0.01) due to the aberra-tions of chromatid type. The level of chromosome aberrations in centenarians' bystander cells (2.84 ± 0.51 per 100metaphases) was not significantly different from the control (p >0.05). The bystander effect was registered in 83%of teenagers, 90 % middle-aged persons and 50 % of the elderly persons. CONCLUSIONS: In the non-irradiated blood lymphocytes of teenagers, middle-aged and elderly persons under condi-tion of co-cultivation with cells X-irradiated in vitro in a dose of 0.25 Gy the bystander effect was induced. In thenon-irradiated centenarians' blood lymphocytes the bystander effect was not revealed. Interindividual variability inthe induction of bystander effect was registered. The development of bystander effect was independent on the levelof chromosomal instability in control cultures.

Comparative analysis the frequency and spectrum of chromosome aberrations in irradiated in vitro peripheral blood lymphocytes of the elderly and centenarians from Kyiv. / PORIVNIaL'NYY̆ ANALIZ RIVNIa TA SPEKTRU ABERATsIY̆ KhROMOSOM V OPROMINENYKh IN VITRO LIMFOTsYTAKh PERYFERYChNOÏ KROVI OSIB LITN'OGO VIKU TA DOVGOZhYTELIV m. KYIeVA.

OBJECTIVE: To establish and compare the frequency and spectrum of chromosome aberrations under X radiation exposure in vitro in dose 0.25 Gy peripheral blood lymphocytes of the elderly and centenarians. MATERIAL AND METHODS: Material of cytogenetic research were peripheral blood lymphocytes from 11 elderly and 10 centenarians, which were irradiated in vitro in dose 0.25 Gy and cultured by generally accepted semi micromethod; slides of metaphase chromosomes were GTG stained and analyzed under the microscope with magnification x 1000. RESULTS: Under irradiation of blood in vitro the mean group frequencies of chromosome aberrations exceeded such without irradiation (р < 0.001) and were 11.60 ± 0.95 аnd 6.82 ± 0.63 per 100 cells in the elderly and the centenar ians, accordingly. Radiation induced increase in the frequency of chromosomal injuries occurred due to chromo some type aberrations which are markers of radiation exposure. In the elderly the elevated frequency of chromatid type aberrations also was registered what is considered a sign of chromosome instability. CONCLUSIONS: The results indicate increased sensitivity the blood lymphocytes from the elderly to radiation expo sure in low doses and allow to assume the advantage of persons with hereditary determined chromosomal stability in achieving longevity.

Damage of chromosoms under irradiation of human blood lymphocytes and development of bystander effect. / POShKODZhENNIa KhROMOSOM PRY OPROMINENNI LIMFOTsYTIV KROVI LIuDYNY TA ROZVYTKU EFEKTU SVIDKA.

OBJECTIVE: the research the distribution of radiation induced damages among chromosomes and their bands in irra diated in vitro human blood lymphocytes and in unirradiated bystander cells.Material and methods of research: cultivation of human peripheral blood lymphocytes by semi micromethod D.A. Hungerford, modeling of radiation induced bystander effect in mixed cultures consisting of irradiated in vitro and non irradiated blood lymphocytes from persons of different gender, GTG staining of metaphase chromosomes and their cytogenetic analysis. RESULTS: Break points in chromosomes under the formation of aberrations were identified in exposed in vitro human peripheral blood lymphocytes in doses 0.25 Gy (95 breaks in 1248 cells) and 1.0 Gy (227 breaks in 726 cells) and in non irradiated bystander cells under their joint cultivation with irradiated in vitro human lymphocytes (51 breaks in 1137 cells at irradiation of adjacent populations of lymphocytes in dose 0.25 Gy and 75 breaks in 1321 cells at irradiation of adjacent population of lymphocytes in a dose 1.0 Gy). The distribution of injuries among the chromo somes and their bands was investigated. CONCLUSIONS: in radiation exposed in vitro human peripheral blood lymphocytes as well as in bystander cells the fre quency of damaged bands and number of breaks which localized in them exceeded the control value (p < 0.01). As under direct radiation exposure, as under formation of breaks due to induction of bystander effect, chromosomes were damaged according to their relative length. Location of bands with increasing number of breaks coincided with the «hot spots¼ of chromosome damage following irradiation and fragile sites. More sensitive to damage were G negative euchromatin chromosome bands, in which were localized 82 88 % breaks. Damageability of telomeric regions in the irradiated cells had no significant difference from the control, while in bystander cells was lower than control value (p < 0.05).

Chromosomal mutagenesis in human somatic cells: 30-year cytogenetic monitoring after Chornobyl accident.

In the lecture we have generalized and analyzed the data of cytogenetic laboratory of National Research Center for Radiation Medicine of the National Academy of Medical Sciences of Ukraine on 30-year selective cytogenetic monitoring among the priority contingents of different ages exposed to radiation after Chornobyl accident in Ukraine. It is highlighted that not only targeted but also untargeted radiation-induced cytogenetic effects should be explored, especially in delayed terms following radiation exposure. The new methodical approaches for studying "bystander effect", individual radiosensitivity, and various forms of radiation-induced chromosomal instability (delayed, hidden, transmissible) have been proposed. These approaches proved to be advantageous for analyzing cytogenetic patterns of induction and persistence of chromosomal instability in human somatic cells because of "bystander effect" and "bystander type effect". The phenomenon of positive "reverse" bystander effect has been found. The possibility of modifying the inherited individual human susceptibility to mutagenic exposure by ionizing radiation has been estimated. Finally, the association between hypersensitivity to radiation exposure and realization of oncopathology in exposed individuals has been revealed. The increased intensity of human somatic chromosomal mutagenesis was confirmed not only in the nearest but in the delayed terms following Chornobyl accident as a result of radiation-induced both targeted and untargeted cytogenetic effects. Such effects can be considered as risk factors for malignant transformation of cells, hereditary diseases, birth defects, and multifactorial somatic pathology. This article is a part of a Special Issue entitled "The Chornobyl Nuclear Accident: Thirty Years After".

Investigation of modification X-ray induced bystander effect in vitro. / Doslidzhennja modyfikacii' efektu svidka, indukovanogo rentgenivs''kym vyprominjuvannjam v umovah IN VITRO.

UNLABELLED: Objective - to investigate the modification of bystander effect induced by X-irradiation of human peripheral blood in vitro by application of antioxidant vitamin medication. Material and methods. Modeling of radiation-induced bystander effect in vitro in mixed lymphocyte cultures exposed to dose of 1 Gy and non-irradiated blood lymphocytes of persons of different sexes, GTG-staining of metaphase chromosomes and their cytogenetic analysis; application of antioxidant preparation (soluble forms of vitamins E, C and A) in concentration 40 µg/ml. Results. Under the introduction of antioxidant preparation into mixed culture before lymphocytes cultivation frequency of chromosomal aberrations in bystander cells did not significantly different from the control (p > 0.05). CONCLUSIONS: application of antioxidant preparation modifies the radiation-induced bystander effect in unirradiated human peripheral blood lymphocytes under their joint cultivation with lymphocytes irradiated in dose of 1 Gy. Antioxidant prevents the development of secondary oxidative stress in unirradiated cells, eliminates the development in them of radiation-induced bystander effect and ensures the preservation of stability of their chromosome apparatus.

[Radiation-induced bystander effect].

Data concerning induction mechanisms, the objects and methods of investigation of a non-target radiobiological phenomenon bystander effect, its role in radiation-induced genomic instability and oncogenesis are summarized.

[Chromosome aberration frequency in children with chronic thyroiditis born before and after the accident at the Chernobyl nuclear reactor]. / Chastota aberatsii khromosom u ditei z khronichnym tyreoïdytom, narodzhenykh do ta pislia avariï na ChAES.

Children with chronic thyroiditis born before and after Chernobyl accident have been investigated cytogenetically using G-banding staining. It was shown that the chromosome instability and sensitivity to cesium radioisotopes increased and the pathological process in a thyroid gland implemented in persons exposed to 131I in their childhood and living in iodine-deficient territories.

[The level of spontaneous chromosome aberrations in children from ecologically clean region of Ukraine studied with cytogenetic analysis of uniformly and differentially stained metaphase chromosomes]. / Riven' spontannykh khromosomnykh aberatsii u ditei z ekolohichno chystoho rehionu Ukraïny, vstanovlenyi pry tsytohenetychnomu analizi rivnomirno ta dyferentsiino zabarvlenykh metafaznykh khromosom.

The frequency of chromosome aberrations in children from Lviv region of Ukraine born after Chernobyl accident have been determined using conventional and G-banding staining.

[The distribution of radiation-induced breaks in the chromosomes of irradiated subjects]. / Rozpodil radiatsiino indukovanykh rozryviv u khromosomakh oprominenykh osib.

Distribution of radiation-induced breakpoints in chromosomes and its bands in persons recovered from acute radiation sickness and personnel from Chernobyl NPP were investigated using G-banding staining. The frequency of damaged bands and breakpoints in groups exposed to radiation was significantly higher as compared with the control group. It was shown that in exposed to radiation persons damage depends on its length. Most frequently damaged bands in the observed groups were determined. The G-negative bands and telomeres of chromosomes were more sensitive to radiation.

[The detection of stable and unstable markers of radiation action in persons with a history of chronic irradiation using the methods of routine and differentiated staining of metaphase chromosomes]. / Vyiavlennia stabil'nykh ta nestabil'nykh markeriv radiatsiinoï diï u osib, shcho zaznaiut' khronichnoho oprominennia, za dopomohoiu metodiv rutynnoho ta dyferentsiinoho zabarvlen' metafaznykh khromosom.

A comparative cytogenetic observation of a group from Chernobyl NPP personnel has been carried out using conventional and G-banding staining. Detection rate of stable aberration by conventional staining to G-banding was 0.20.

[The incidence of chromosome aberrations in the post-Chernobyl period in persons who reside in the city of Kyïv]. / Chastota khromosomnykh aberatsii v pisliachornobyl's'kyi period u osib, iaki meshkaiut' u m. Kyievi.

A comparative cytogenetic examination of 10 healthy persons in the age of 24-56 years old living in Kyïv with no known the occupational or medical exposure to clastogens has been carried out using conventional and G-banding staining. The cytogenetic effect revealed by conventional staining was in the background range. New data about the level of symmetrical and asymmetrical exchanges of chromosomes from unexposed individuals were established using G-banding staining. They composed 0.67 +/- 0.32 and 0.19 +/- 0.17 per 100 cells, respectively.