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6th LOWRAD, October 17-20, 2007, Budapest, Hungary

Abstracts

The abstracts are in alphabetical order according to the first author

CONCENTRATION AND VERTICAL DISTRIBUTION OF Cs-137 IN THE UNDISTURBED SOIL OF SOUTHWESTERN NIGERIA

I.R. Ajayi

Dept of Physics, Adekunle Ajasin University, Akungba-Akoko, Nigeria

The results of measurements of Cs-137 in soil profiles which were sampled in undisturbed soil in Ondo, Ekiti and Oyo states in the southwestern area of Nigeria are presented in this paper. Samples were collected from nine soil profiles. The vertical distribution of Cs-137 in the soil profiles have been determined. Caesium concentration ranged from 0.31  0.10 Bqkg-1 in the 0-2 cm depth to a maximum of 1.25  0.21 Bqkg-1 in the 6-8 cm depth at some sites and from 3.16  0.16 Bqkg-1 in 0-5 cm depth to below detection limit (BDL) at 20-25 cm at another site. The results generally show that fifteen years after the chernobyl accident and more than 40 years after the nuclear probes, Cs-137 still remains within 25 cm of upper layer of soil in the region and its penetration in the soils is a very slow process. The mean value of effective dose commitment due to the presence of caesium in soil in the entire region was found to be 10.77µSv.

DETERMINATION OF NATURAL RADIOACTIVITY IN DRINKING WATER IN PRIVATE DUG WELLS IN AKURE, SOUTHWESTERN NIGERIA.

AJAYI, O.S. and OWOLABI, T.P

Department of Physics, Federal University of Technology, P.M.B. 704, Akure. Nigeria

ajayisam1089@

A gamma-ray survey and analysis of drinking water from 20 private dug wells from Akure, Southwestern Nigeria have been conducted in this work. These were done in order to quantify the activity concentrations of the gamma emitters 226Ra and 228Ra from 238U and 232Th series respectively as well as 40K in these private well waters. Measurements were done using high-resolution high-purity (HPGe) vertical co-axial detectors (Canberra, GC 2018-7500 model) coupled to a Canberra Multichannel Analyzer (MCA) computer system. Activity concentrations ranged from 0.57 to 26.86Bq l-1, 0.20 to 60.06Bq l-1 and 0.35 to 29.01Bq l-1 for 226Ra, 228Ra and 40K respectively. The measured radionuclide concentrations were compared with data from other parts of the world and used to estimated annual effective dose for age groups  1y, 2-7y and  17y. Total annual effective doses from the intake of these radionuclides in dug well drinking water ranged from 0.02 to 76.84mSv y-1, 0.02 to 38.80mSv y-1 and 0.05 to 481.60mSv y-1 for age group  1y, 2-7y and  17y respectively. The total annual effective doses were considerably higher than both the World Health Organisation (WHO) and the International Commission on Radiological Protection (ICRP) recommended limits.

ANALYSIS OF THE EXPERIENCE OF PROVIDING RADIATION PROTECTION OF POPULATION AND ENVIRONMENT WITHIN THE INTERNATIONAL COLLABORATION NETWORK

Sergei Aleksanin, Eugene Zheleznyakov, Regina Fedortseva

All-Russian Center of Emergency and Radiation Medicine (ARCERM), St. Petersburg, Russian Federation

The All-Russian Center of Emergency and Radiation Medicine (ARCERM) in St. Petersburg is a specialized radiation health institution and World Health Organization (WHO) collaborating center within the Radiation Emergency Medical Preparedness and Assistance Network (REMPAN), which primary objectives are:

  • To promote medical preparedness for radiation accidents and radio-nuclear threats among WHO Member States;

  • To provide medical and public health advice, assistance and coordination of medical management at international and regional levels in the case of a nuclear accident or radiological emergency;

  • To assist in follow-up studies and rehabilitation.

ARCERM serves as a national focal point for advice and possible medical care in cases of radiation injuries in humans as well as assists WHO to prepare relevant documents and guidelines, provides training in radiation medicine, distributes relevant information to the medical community and the public and carries out scientific investigations on radiation effects on humans. The Center is prepared to undertake actions on medical management of possible radiation emergencies both on national and international level as a member of REMPAN network. The assistance provided by ARCERM may also include providing radiation medicine and other appropriate specialists, scientific services and expertise, equipment and medical services for diagnosis, prognosis, medical treatment and medical follow-up of persons affected by radiation.

In case of radiation accident the Center has standard operating procedures at country level. It includes the system of warning and data collection, setting up special wards for receiving radiation victims, radioactivity control station, primary deactivation and treatment as well as providing personal protection for staff. WHO, as well as other co-operating international organizations, are notified and provided with relevant information through the International Atomic Energy Agency (IAEA). WHO helps establish a link between the country and REMPAN assisting center(s) and Regional Offices, keeping all REMPAN centers informed about the details of the accident and progress in its management.

ARCERM has all necessary capacities to perform its activities, which include 120 in-patient beds, excellent diagnostic facilities and research laboratories, psychological support team as well as qualified staff including specialists in a wide range of medical fields. The database of radiation case histories includes long-term follow-up information on 16 thousands of over-exposed persons, mostly clean-up workers of Chernobyl accident.

In November 2004 the simulation exercise was carried out with participation of ARCERM as a major player in emergency response to radiation accident. Telemedicine facilities were actively used during the exercise. In October 2006 another large-scale simulation exercise within the framework of Russia-NATO collaboration was held in Rome, Italy with the participation of ARCERM.

ARCERM regularly participates in biannual meetings between REMPAN members to promote cooperation within the network, to exchange information and experience and to maintain the network in a permanent operating state. The 10th REMPAN meeting was hosted by ARCERM in St. Petersburg in 2004.

IN VIVO TRANSCRIPTOME MODULATION AFTER LOW DOSE OF HIGH ENERGY NEUTRON IRRADIATION

R. Amendola1, E. Fratini1, M. Piscitelli1, D. E. Sallustio1, M. Angelone2, M. Pillon2, F. Chiani3, V. Licursi3, R. Negri3.

1ENEA, BAS BIOTEC MED, Roma, Italy; 2ENEA, FUS TEC, Frascati, Italy; 3Università La Sapienza, Dip. Biologia Cellulare e dello Sviluppo, Roma, Italy

Objective: This project aims to the identification of an hypothetical transcriptome modulation of mouse peripheral blood lymphocytes and skin after exposure to high energy neutron in vivo. Positive candidate genes isolated from mice in in vivo experiments will be selected and evaluated for both radioprotection issues dealing with cosmic ray exposure, and for biomedical issues mainly for low doses and non-cancer effects.

Methods: High energy neutron irradiationis performedat the ENEA Frascati, neutron generator facilities (FNG), specifically dedicated to biological samples. FNG is a linear electrostatic accelerator that produces up to 1.0x1011 n/s 14 MeV neutrons via the D-T nuclear reaction. The dose-rate applied for this study is of 0.7 cGy/min. The functional genomic approach has been performed on six animals for each experimental points: un-irradiated; 20 cGy, 6 hours and 24 hours delayed time after exposure. Preliminarly, a pool of total RNA is evaluated on commercial micro-arrays containing large collections of mus musculus cDNAs. Statistical filtering and functional clustering of the data is carried out using dedicated software packages.

Results: Candidate genes are selected on the basis of responsiveness to 20 cGy of exposure, with a defined temporal regulation. We plan to organize a systematic screen focused on genes responding to our selection criteria, in in vivo mouse experiments, and correlate their differential expression to the human counterparts. A specific cross species database will be created with all the functional information available in standardized format (MIAME: minimal information about micro-arrays experiments).

Conclusions: A lack of information on in vivo experiments is still evident for low doses exposure, especially for neutron of cosmic interest. Individual susceptibility, extensive number of animals to be processed, lack of standardization methodologies are among problems to be solved for these studies. To this end, we pursue to define a pattern of expression related to tissues of pivotal interest for both health and biomarkers exposure.

The project is partially funded by Italian Space Agency (ASI), MOMA Contract, 2006-2009.

DIFFERENTIAL MODIFICATION OF THE PSEUDOMONAS AERUGINOSA PAO1 OUTER MEMBRANE UNDER HYDROGEN PEROXIDE AND GAMMA RAY

Byung Chull An, Jae-Sung Kim, Seung Sik Lee, Shyamkumar Barampuram, Eun Mi Lee, Seung Gon Wi, Woo Jun Park and Byung Yeoup Chung

Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup 580-185, Korea

Objective:Pseudomonas aeruginosa PAO1 is causes opportunistic infections in humans. Studies with animals suggest that an adaptive mechanism is important for the ability of P. aeruginosa PAO1. The adaptive mechanism is protective mechanism against oxidative stress. This mechanism is aimed at preventing by reactive oxygen species. Reactive oxygen species can induce and modulate a variety of biological responses including gene expression.

Materials and Methods:Pseudomonas aeruginosa PAO1(a wild-type strain) was grown aerobically with vigorous shaking at 30oC in LB broth (Difco). When the optical cells density at 600 nm reached 0.4 that exposed to 0.5-50 mM H2O2 for 30 min and 30-100 Gy Gamma irradiation (60Co, ca.150 TBq of capacity, AECL) for 30 min. For the recovery, the cultures were immediately exchanged fresh media and incubation for 30 min. then, cells were prefixed with 2.5% glutaraldehyde for 30 min at 4oC. After two washes by centrifugation at 15,000 X g for 5 min each, the cells were postfixed with 1% osmium tetroxide for 16 h at 24oC. The sample was dehydrated with absolute ethanol, stained with 2% uracyl acetate, embedded in Epon resin. Thin sections were stained with lead citrate and uranyl acetate and observed with a electron microscope. Expression level of candidate genes were analyzed using real-time PCR. The amplification program was consist of one cycle at 94oC for 30 sec, followed 40 cycles of 94oC (5 sec) - 60oC (31 sec).

Results and Conclusion: In the present study, we have observed differential membrane damage to P. aeruginosa PAO1 cells when exposed to different oxidative stresses such as hydrogen peroxide 0.5-50 mM for 30 min and gamma radiation 30-100 Gy for 30 min using TEM. In oder to understand its behaviour, we isolated 3 genes which are related to membrane maintaining. Its transcription level was identified using Real-Time PCR. Each gene was differently expressed under various stresses.

RADIATION STERILIZATION OF HARMFUL ALGAE IN WATER

Byung Chull An, Jae-Sung Kim, Seung Sik Lee, Shyamkumar Barampuram, Eun Mi Lee, Byung Yeoup Chung

Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute,
Jeongeup 580-185, Korea,

Objective: Drinking water, water used in food production and for irrigation, water for fish farming, waste water, surface water, and recreational water have been recently recognized as a vector for the transmission of harmful micro-organisms. The human and animal harmful algae is a waterborne risk to public health and economy because the algae are ubiquitous and persistent in water and wastewater, not completely removed by physical-chemical treatment processes, and relatively resistant to chemical disinfection. Gamma and electron beam radiation technology is of growing in the water industry since it was demonstrated that gamma and electron beam radiation is very effective against harmful algae.

Materials and Methods: Harmful algae (Scenedesmus quadricauda(Turpin) Brebisson 1835 (AG10003), Chlorella vulgaris Beijerinck 1896 (AG30007) and Chlamydomonas sp. (AG10061)) were distributed from Korean collection for type cultures (KCTC).

Strains were cultured aerobically in Allen's medium at 25℃ and 300 umol/m2s for 1 week using bioreactor. We investigated the disinfection efficiency of harmful algae irradiated with gamma (0.05 to 10 kGy for 30 min) and electron beam (1 to 19 kGy for 5 sec) rays.

Results and Conclusion: We investigated the disinfection efficiency of harmful algae irradiated with gamma and electron beam rays of 50 to 19000 Gy. We established the optimum sterilization condition which use the gamma and electron beam radiation. Gamma ray disinfected harmful algae at 400 Gy for 30 min. Also, electron beam disinfected at 1000 Gy for 5 sec. This alternative disinfection practice had powerful disinfection efficiency. Hence, the multi-barrier approach for drinking water treatment in which a combination of various disinfectants and filtration technologies are applied for removal and inactivation of different microbial pathogens will guarantee a lower risk of microbial contamination.

Chromosomal aberrations in Mobile Phone users in Tamilnadu, Southern India.

V.Balachandar, B.Lakshman Kumar, resh, R.Sangeetha, P.Manikantan and K.Sasikala

Human Genetics Laboratory, Department of Zoology, Bharathiar University, Coimbatore, Tamilnadu, INDIA

Radiofrequency (RF) waves have long been used for different types of information exchange via the airwaves—wireless Morse code, radio, television, and wireless telephony. Increasingly larger numbers of people rely on mobile telephone technology, and health concerns about the associated RF exposure have been raised, particularly because the mobile phone handset operates in close proximity to the human body, and also because large numbers of base station antennas are required to provide widespread availability of service to large populations. In the present study chromosomal damage investigations were carried out on the peripheral blood lymphocytes of individuals using mobile phones, being exposed to MW frequency ranging from 800 to 2000 MHz.

The aim of this study is to establish whether mobile phone use (n = 27) increases the frequency of chromosome aberrations (CA) in peripheral blood lymphocytes compared with controls (n = 27) in Tamilnadu, India. After signing a consent form, volunteers provided blood samples (5 ml) to establish cell cultures at 52 hrs. For CA analysis, 100 complete metaphase cells from each subject were evaluated.

In the present study, in mobile phone users highly significant results were obtained when compared to control groups.

These results highlight a correlation between mobile phone use (exposure to RFR) and genetic damage and require interim public health actions in the wake of widespread use of mobile telephony.

Key words: Mobile phone users, Chromosomal Aberrations, Tamilnadu

RISK OF RADON PROGENIES AND THE LNT HYPOTHESIS

I. Balásházy1, I. Szőke1, Á. Farkas1, A. Filep1, Sz. Zichler2, B.G. Madas1

1Hungarian Academy of Sciences KFKI Atomic Energy Research Institute,

P.O. Box 49, H-1525 Budapest, Hungary

2Technoorg-Linda Co. Ltd., Rózsa u. 24, H-1077 Budapest, Hungary

Epidemiological investigations, cell and animal irradiation experiments have demonstrated that ionizing radiation may induce cancer and the risk from exposure of comparatively high levels of ionizing radiation is proportional to dose. However, the biological response to low doses of radiation is poorly understood. In this dose range, the linear-non-threshold (LNT) dose – effect hypothesis is recommended in current radiation protection applications. Inhaled radon progenies present more than the half of the natural radiation burden. The numerical description of their deposition along the airways and the quantification of the related cellular radiation burden may provide useful information regarding the health effects of low doses and LNT hypothesis.

Histological studies of lungs of former uranium miners present strong correlation between primer deposition hot spots and neoplastic lesions. Most of these lesions were located along the carinal regions of the large bronchial airways in generations 3-5.

In the present work, computational fluid dynamics approaches have been applied to simulate the deposition distribution of inhaled radon progenies within the upper and central human airways. The geometry and epithelial lung tissue were digitally reconstructed based on anatomical and histological data available in the literature. Single and multiple hit distributions of alpha-tracks with epithelial cell nuclei and distributions of cell nucleus doses have been computed applying Monte Carlo modelling techniques. The unit track length microdosimetric approach has been integrated into the model to compute cell death and cell transformation probabilities.

Based on the results, local deposition densities, hit probabilities and other microdosimetric parameter values may be up to two-three orders of magnitude higher than the average values. Cellular radiation dose calculations revealed that some cells or cell clusters may receive high doses even at low exposure conditions. Applying the model to different radiation burdens useful relations can be received regarding the LNT hypothesis.

This research was supported by the Hungarian NKFP-3/A-089/2004, NKFP-1/B-047/2004, GVOP-3.1.1-2004-05-0432/3.0, OMFB-445/2007 and K61193 OTKA Projects.

EARLY PROGENITOR CELLS ANTIGENS AND APOPTOSIS IN PATIENTS WITH SECONDARY MYELODYSPLASIA EXPOSED TO LOW-DOSE IONIZING RADIATION AFTER CHERNOBYL ACCIDENT

Bazyka D., Ilyenko I., Klymenko S., Lubarets T., Belyaeva N.

Research Center for Radiation Medicine, Kiev, Ukraine

Background:Myelodysplastic syndromes are clonal myeloid disorder characterized by ineffective hemopoiesis associated with bone marrow dysplasia, resulting in myeloid leukemia. Increased apoptosis has been shown in MDS as a possible explanation for this paradox. Increase of apoptosis was demonstrated in healthy individuals exposed to low-dose irradiation. indicating its possible modifying role on the myelodysplasia pathway after irradiation.

Patients and Methods:A study of bone marrow (BM) and peripheral blood (PB) was performed in 49 MDS patients (refractory anemia (RA) - 25; refractory anemia with the excess of blasts (RAEB)- 16 cases; refractory anemia with the excess of blasts in transformation (RAEB-t) – 6; chronic myelomonocytic leukemia (CMML)– 2 cases). Age was between 30-77 years (mean – 55,7). In 14 patients MDS was initiated at the late period after low-dose irradiation during clean-up works at Chernobyl accident (mean dose 239.0+35.6 mSv); 15 were exposed at the radiation-contaminated territories (24.3+6.2 mSv). Control group included 20 healthy donors (mean age 51,0). Expression of CD 34, CD13, CD33, CD71, CD117, HLA-DR and bcl-2 protein was studied by flow cytometry analysis. Spontaneous and verapamil-induced apoptosis was measured by Annexin V assay and CD95 expression. Flow cytometry analysis was performed using a FACScan flow cytometer.

Results: RAEB, RAEB-t and CMML were characterized by high CD34+ (68,0±7,08%), CD71+, CD117+ or CD117+34+ cell counts associated with poor prognosis and transformation to acute leukemia. BM CD34+ cell subset demonstrated the prevalence of the lineage committed progenitors. In RA a statistically significant increase of mean values of fluorescence intensity of CD117,CD33, CD34 and CD71 antigens was observed together with a significant decrease of SSC parameters in granulocytes population of PB and BM in MDS patients compared with healthy donors group (р<0, 01). Hypogranularity in granulocytic region in BM is more marked in comparison with PB.

High level of apoptosis compared with healthy donors group was observed in RA cases, whereas a switch to a low level of apoptosis was detected in the RAEB, RAEB-t and CMML blasts. Cells demonstrated an increase of verapamil-induced apoptosis in the Annexin-V/PI test as comparing with the spontaneous apoptosis levels. For granulocytes a significant increase of the verapamil-induced apoptosis was shown in vitro. Patients with MDS had significantly increased expression of CD95 antigen (р<0, 01). Positive correlations were found between over-expression of CD 95 and the expression of CD34-receptor in RAEB, RAEB-t, CMML groups. Levels of CD 95 andBcl-2 expression in RAEB, RAEB-t, CMML groups show negative correlations for lymphocytic (r = -0,72; р<0,03) and granulocytic (r = -0,90; р<0,001) populations. In RA such correlations were not shown for Fas-receptor and Bcl-2 positive cell counts in lymphocytes to the contrary to granulocytes, in which the statistically significant correlation between these values (r = -0, 84; р<0,005) was detected. Radiation exposed showed the highest CD95+ and low bcl2+ cell counts.

Summary.This study demonstrated some correlations of between early progenitors and increased apoptosis in myelodysplasia patients. СD95 apoptotic cells fraction and verapamil-induced apoptosis seem to be substantially higher in radiation exposed than in other MDS cases.

RADIATION EFFECTS ON MAN HEALTH, ENVIRONMENT, SAFETY, SECURITY: GLOBAL CHORNOBYL MAPPING

V. Bebeshko, D. Bazyka, S. Volovik, K. Loganovsky, V. Sushko, J. Siedow , H. Cohen, G. Ginsburg, N. Chao, J. Chute, M. Samuhel, W. Holden,

N. Steinberg Research Center for Radiation Medicine, Kiev, Ukraine; Duke University, Research Triangle Institute, NC, USA

Objectives: Ionizing radiation is a primordial terrestrial and extraterrestrial background and archetypal environmental stress-factor for life origin, evolution, and existence. We all live in radiation world inevitably involving nuclear energy production, nuclear weapon, nuclear navy, radioactive waste, pertinent medical diagnostics and treatment, etc with connected certain probability of relevant accidents and terrorist attack, space and jet travels, high natural background radiation, etc - actual and potential sources of radiation exposures and effects. State-of- the art integral fundamental research on radiation effects on man health, environment, safety, and security (REMHESS) is nowadays paramount necessity and challenge.

Methods and results: In given generalized conceptual framework unique 20 years Chornobyl multidimensional research and databases for radiation effects on man’s all organism systems represent invaluable original basis and resources for mapping Chornobyl data and REMHESS challenge .Granted by DOE brand new Chornobyl Research & Service Project based on “Sarcophagus-II” (Object “Shelter”) workers only one in radiation history baseline cohort, corresponding biorepository prospective dynamic data, integrated conceptual database system, and “state of the art” “omics” (genomics, proteomics, metabolomics) analysis is designed specifically for coherent addressing global REMHESS problems. In this connection “Sarcophagus-II” is only one unique universal model.

Conclusions: The fundamental goals of novel strategic Project and global Chornobyl mapping are to determine specific “omics” signatures of radiation for man depending of exposure peculiarity to understand ultimate molecular mechanisms of radiation effects, gene-environment interactions, etiology of organisms systems disorders and diseases, and to develop new biomarkers and countermeasures to protect man health in the framework of global REMHESS challenge.

Acknowledgment: This study is supported by the DOE Award Number DE-FC01-06EH06028.

Low dose radiation effects on the transcription of consensus radiation response genes in primary and immortalized human fibroblast cells

A. Benedek, E. Kis, H. Hegyesi and G. Sáfrány

Department of Molecular and Tumor Radiobiology, F. Joliot-Curie National Research Institute for Radiobiology and Radiohygiene, Budapest, Hungary

OBJECTIVE: The linear non-threshold model suggests that tumors might be induced even by low radiation doses. Still, most of the conventional methods are unable to detect damages below 100 mGy. We have studied whether transcriptional responses of consensus radiation response genes can be detected after low dose radiation exposure in directly exposed or bystander primary human fibroblast cells. The short term proliferation capacity of primary fibroblast cells in culture limits their long term application. Therefore we tried to immortalize the cells by the introduction of the human telomerase gene using retroviral vectors.

METHODS: Primary human fibroblast cell lines were established from skin biopsies of cancer patients and foreskin samples of young children. To create immortalized cell lines the human telomerase gene was cloned into a retroviral vector. Primary fibroblast cells were transduced and their proliferation capacity studied. To investigate radiation induced transcriptional alterations, cells were irradiated with 60Co γ-rays (0; 0.01; 0,04; 0,1; 2 and 8 Gy) and 2 hours later total cellular RNA was isolated both from directly exposed and bystander cells. Transcriptional alterations were followed in consensus radiation response genes (CDKN1, GADD45, GDF15, IER5, PLK3, TP53INP1) with quantitative real time PCR (Corbett/ SybrGreen).

RESULTS: There is an elevated expression of CDKN1, GADD45, GDF15, PLK3, TP53INP1 in the exposed cells. We see only for the PLK3 a dose-dependent increase which manifested also at low doses. It seems this gene is the most sensitive to radiation at low doses. The hTERT-immortalized cells were morphologically identical to the primary cells. the radiation-induced transcriptional profile of immortalized cells were very similar to the primary ones.

CONCLUSIONS: hTERT immortalized cells can be used to mimic alterations in primary cells. Low dose irradiation doesn’t influence the expression of most of the studied genes. PLK3 might be an efficient marker to estimate individually low dose effects.

Transcriptomic analysis of the effect of embryonic irradiation on Cognitive functions

M. A. Benotmane, J; Verheyde, L. Leyns, A. Michaux, A. Janssen, M. Neefs & L. de Saint-Georges

Belgian Nuclear Research Centre 'SCK•CEN', Boeretang 200 2400 Mol Belgium

abenotma@sckcen.be

Brain damage induced by prenatal irradiation is of major concern in radioprotection. The brain is the final result of a series of well timed consecutive or concomitant waves of cellular proliferation, migration, and differentiation. Acute irradiation during pregnancy could selectively disturb these events to result in various forms of malformation such as microcephaly, reduced cortical thickness and mental retardation. Such events were previously described in epidemiological studies of the atomic bomb survivors of Hiroshima/Nagasaki.

Using cDNA-microarrays and real-time PCR we analyzed the modulated genes upon 50 cGy X-ray irradiation in embryonic mouse brain. The main activated pathways are involved in the induction of Trp53 dependent programmed cell death, and the intercellular signalling cascades. The strong upregulation of Ccng1, Trp53inp1 and Cdkn1a suggested that the tumour suppressor P53 is an essential regulator of the radiation induced stress response. Although in the Trp53 null mutant embryos, our data highlights differential expression of genes involved in cell cycle progression. Various cyclins and cyclin-dependent kinases were downregulated.

Regional analysis of the irradiated anterior brain at E15 by in situ hybridization with Trp53inp1 and Ccng1 probes, suggested that there is a specific regional dependent expression in the anterior brain. Especially Ccng1 and the P53 downstream cell cycle regulating gene indicated that the strongest effect can be observed in the cerebral cortex.

Taken together, radiation induced cell death of astrocytes in the cerebral cortex, and reduction in neurite length in maturating neurons, may interfere with a correct patterning of the brain and could jeopardize the formation of a correct neural network, leading to cognitive deficits in the mature brain.

References:

-The role of Trp53 in the transcriptional response to ionizing radiation in the developing brain. Verheyde J, de Saint-Georges L, Leyns L, Benotmane MA. DNA Res. 2006 Apr 30;13(2):65-75. Epub 2006 Mar 21.

-Unraveling the Fundamental Molecular Mechanisms of Morphological and Cognitive Defects in the irradiated Brain. Joris Verheyde, Mohammed Abderrafi Benotmane. Brain Res Brain Res Rev. 2006 Dec 21.

RADIONUCLIDES DETECTED IN LIME SAMPLES THAT CONSUMED WITH TOBACCO AND BETEL NUTS BY PEOPLE OF NORTHEAST INDIA WHERE HEAD AND NECK SQUAMOUS CELLS CANCER (HNSCC) IS PREVALENT

Dilip Bhattacharjee1*, Satoru Endo1, Kenichi Tanaka1, Megu Ohtaki2, Aya Sakaguchi 3, Masayashi Yamamoto 3, Vladislav Y. Golikov 4, and Masaharu Hoshi1

1Department of Radiation Biophysics, International Radiation Information Center and 2Department of Environmetrics and Biometrics, Research Institute for Radiation Biology and Medicine, Hiroshima University, 1-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan. 3Low Level Radioactivity Laboratory, Kanazawa University, Ishikawa 923-1224, Japan. 4Institute of Radiation Hygiene, St. Petersburg 197101, Russia.

Head and neck squamous cell cancer (HNSCC) is a very predominant type of cancer amongst the population of northeastern states of India than the rest of the world. Epidemiological and other data suggest consumption of betel nuts with/without tobacco and lime or tobacco alone with lime is a probable cause of high cancer incidence. The fundamental question arises that why this particular cancer is induced more in this region while people follow the similar habits elsewhere. Here we report the results on analysis of lime samples, collected from 12 different locations spectrophotometrically by high-purity germanium detector. The calculated activity of radionuclides showed to an average of 2.68, 0.10 and 0.83 Bq/gm for 238U, 235U and 232Th series respectively for ten samples which are about 8 times higher than the normal background level of 0.37, 0.02 and 0.02 Bq/gm for 238U, 235U and 232Th series found in control samples, collected from outside of northeast. The results conclusively showed for the first time that the lime samples almost throughout the northeastern India contain high proportion of radionuclides of uranium, thorium and actinides series. Further, annual effective dose of gamma radiation calculations from these results of earth’s crust in northeast showed that gamma rays emitted at an average dose of up to 2.5 mSv/year/consumer approximately. This dose calculation in the oral cavity is underestimated as short range radiations by decay of alpha, beta and electron-capture etc are not considered in the present study. Continuous exposure of such low dose radiations emitting from different radionuclides to the sensitive squamous cells of the oral cavity for a long twenty years or more amounting to a total minimum dose of at least 50 mSv evidently contributes towards excessive HNSCC to the people of northeast than other parts of India.

*Former Scientist, Radiation and Health Sciences Division, Bhabha Atomic Research Centre, Mumbai 400 085, India.

Email: dilip1339@/indianjrr@

Effect of Magnetic field on the living cells and chromosomes

Sima Bhattacharya and P.K.Poddar

Department of Botany, University of Kalyani, Nadia, West Bengal. India, Pin.-741235

Magnetic field of 2.25X103 Gauss was applied for 30 minutes, 60 minutes and 9o minutes on the living meristematic cells of Lathyrus sativus L., a leguminous plant and on the bone marrow cells of albino Swiss mice, Mus musculus L.

Mitotic indices in meristematic cells of magnetic field treated plants at different times of treatment were found increased compared to those of control sets.

Chromosomal abnormalities of magnetic field treated plants were polyteny, aneuploidy, polyploidy, clumping, chromosome erosion and anaphase bridge.

Usual aceto-ocein, root tip squash technique was followed in this endeavour.

In situ estimation of nuclear DNA in meristematic cells of magnetic field treated Lathyrus sativus plants showed enhanced DNA content compared to those of the control sets.

In case of magnetic field treated mice similar increase in mitotic indices in bone marrow cells was found compared to those of the untreated ones following the usual flame-dry technique.

Different types of chromosomal aberrations of bone marrow cells of magnetic field treated mice were

acentric fragments, clumping, ring chromosomes, chromatid breaks, pulverization, aneuploidy, micronucleus, polyploidy, centric fusion etc. compared to those of the untreated mice.

Usual C-banding technique revealed the heterochromatin content of the chromosomes of bone marrow

cells in magnetic field treated ones. Centromeric fusion was clearly revealed in this technique. Heterochromatin content was found enhanced in the magnetic field treated bone marrow cells compared to those of untreated ones.

ATR-dependent bystander effects in non-targeted cells

S. Burdak-Rothkamm1,2, K. Rothkamm2 and K.M. Prise1

1Centre for Cancer Research & Cell Biology, Queen’s University Belfast, Lisburn Road, Belfast, BT9 7BL, UK

2Gray Cancer Institute, University of Oxford, Mount Vernon Hospital, Northwood, HA6 2JR, UK

Radiation induced non-targeted bystander effects have been reported for a range of endpoints including the induction of γH3AX foci which serve as a marker for DNA double strand breaks. We have recently reported the induction of γH3AX foci in non-targeted bystander cells up to 48 hours after irradiation and the involvement of reactive oxygen species (ROS) and TGF-beta 1 in the induction of γH3AX foci (Oncogene (2007) 26:993-1002). Here, we wanted to determine the role of the PI3-like kinases ATM, ATR and DNA-PK in DNA damage signalling in bystander cells.

Conditioned medium from T98G cells irradiated with 2 Gy of X-rays was transferred onto non-irradiated cells that were subsequently analysed for the induction of γH3AX, ATR and 53BP1 foci as well as clonogenic survival.

Irradiated T98G glioma cells generated signals that induced γH3AX and 53BP1 foci in cells treated with the conditioned medium from irradiated cells. These foci co-localised with ATR foci. Inhibition of ATM and DNA-PK could not suppress the induction of bystander γH3AX foci whereas the mutation of ATR in Seckel cells abrogated bystander foci induction. A restriction of bystander foci to the S-phase of the cell cycle both in T98G cells and in ATR–proficient fibroblasts was observed. These results identify ATR as a central player within the bystander signalling cascade leading to γH3AX and 53BP1 foci formation, and suggest a mechanism of DNA damage induction in non-targeted cells.

Further investigations have shown decreased clonogenic cell survival in bystander T98G and ATR wild-type fibroblasts. ATR mutated Seckel cells and also ATM-/- fibroblasts were resistant to this effect suggesting a role for both ATR and ATM in the bystander signalling cascade with regard to cell survival.

Taken together, these observations support a hypothesis of DNA damage-induced accumulation of stalled replication forks in bystander cells which are subsequently processed by cellular DNA damage checkpoint and repair mechanisms, including ATR, leading to bystander cell killing.

ON THE ASSESSMENT OF ADVERSE CONSEQUENCES OF CHERNOBYL ACCIDENT

E.B. Burlakova

Emanuel Institute of Biochemical Physics, Russian Academy of Sciences,

Moscow, 119991 Russia

Since 1987 till the present time, at the Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, studies on the effect of low-dose low-level irradiation on biophysical and biochemical parameters of the genetic and membrane apparatus of cells of organs of exposed animals are being carried out. We investigated the structural parameters of the genome (by the method of DNA binding to nitrocellulose filters), structural parameters of nuclear, microsomal, mitochondrial, and plasmic (synaptic and erythrocyte) membranes (by the method of spin probes localized in various layers of membranes), the composition and oxidation degree of membrane lipids, and the functional activity of cells – the activity of enzymes, relationship between isozymic forms, and regulating properties. We investigated also the effect of low-level irradiation on the sensitivity of cells, biopolymers, and animals to subsequent action of various damaging factors, including high-dose irradiation. The animals were exposed to a source of 137 Cs -radiation at the dose-rates 41.6 x 10-3, 4.16 x 10-3, and 0.416 x 10-3 mGy. The doses were varied from 6 x 10-4 to 1.2 Gy. As a result of the studies performed, the following conclusions were made:

  1. Low radiation doses affect actively the metabolism of animals and man.

  2. Over certain dose ranges, low-level irradiation is even more effective than acute high-level.

  3. The dose–effect dependence of irradiation may be nonlinear, nonmonotonic, and polymodal in character.

  4. Doses that cause the extreme effects depend on the irradiation dose-rate (intensity); they are lower at a lower intensity.

  5. . Low-dose irradiation causes changes (mainly, enhancement) in the sensitivity to the action of other damaging factors. [1,2]

We explain the nonlinear and nonmonotonic dose–effect dependence that we obtained in our experiments with low-dose low-level irradiation by changes in the relationship between damages and reparation of the damages. With this kind of low-level irradiation, the reparative systems either are not initiated (induced), or function inadequately, or are initiated with a delay, i.e., when the exposed object has already received radiation damages. Recently, the absence of reparation at low irradiation doses was verified on the cell level, [3] and the complex character of the dose dependence was confirmed [4]. Previously, we published a similar scheme of dependence of damages on irradiation dose, which was different for different dose ranges. According to the scheme, the quantitative characteristics were similar for the doses that differed by several orders of magnitude; in a certain dose range, the effect may have an opposite sign.The results obtained and supported by numerous experiments are important because the above dose dependences made it possible to come to conclusion about a radiogenic or non-radiogenic character of changes observed in an irradiated organism. The indisputable conclusion that if the effect increases with the dose it is evidence for its radiogenic nature is by no means in favor of an opposite statement, i.e., that the absence of a direct dose–effect dependence but its nonmonotonic character is evidence for the absence of a relation of the effect to irradiation. The controversial conclusions of International and Russian organizations stem mainly from the underestimation and misunderstanding of the effects of ultra-low and low irradiation doses, reluctance to apply other criteria to assess the consequences of irradiation on human health, and conviction (groundless) that low doses cause either no damages or such minor damages that they may be neglected and disregarded. In the lecture, data that elucidate the above controversies will be presented.

Salient Features of Low-Level Radiation Effects

E.B. Burlakova

Emanuel Institute of Biochemical Physics, Russian Academy of Sciences,

Moscow, 119991 Russia

Since 1987 till the present time, at the Emanuel Institute of Biochemical Physics, Russian Academy of Sciences, studies on the effect of low-dose low-level irradiation on biophysical and biochemical parameters of the genetic and membrane apparatus of cells of organs of exposed animals are being carried out. We investigated the structural parameters of the genome (by the method of DNA binding to nitrocellulose filters), structural parameters of nuclear, microsomal, mitochondrial, and plasmic (synaptic and erythrocyte) membranes (by the method of spin probes localized in various layers of membranes), the composition and oxidation degree of membrane lipids, and the functional activity of cells – the activity of enzymes, relationship between isozymic forms, and regulating properties. We investigated also the effect of low-level irradiation on the sensitivity of cells, biopolymers, and animals to subsequent action of various damaging factors, including high-dose irradiation. The animals were exposed to a source of 137 Cs -radiation at the dose-rates 41.6 x 10-3, 4.16 x 10-3, and 0.416 x 10-3 mGy. The doses were varied from 6 x 10-4 to 1.2 Gy. As a result of the studies performed, the following conclusions were made:

  1. Low radiation doses affect actively the metabolism of animals and man.

  2. Over certain dose ranges, low-level irradiation is even more effective than acute high-level.

  3. The dose–effect dependence of irradiation may be nonlinear, nonmonotonic, and polymodal in character.

  4. Doses that cause the extreme effects depend on the irradiation dose-rate (intensity); they are lower at a lower intensity.

  5. . Low-dose irradiation causes changes (mainly, enhancement) in the sensitivity to the action of other damaging factors. [1,2]

We explain the nonlinear and nonmonotonic dose–effect dependence that we obtained in our experiments with low-dose low-level irradiation by changes in the relationship between damages and reparation of the damages. With this kind of low-level irradiation, the reparative systems either are not initiated (induced), or function inadequately, or are initiated with a delay, i.e., when the exposed object has already received radiation damages. Recently, the absence of reparation at low irradiation doses was verified on the cell level, [3] and the complex character of the dose dependence was confirmed [4]. Previously, we published a similar scheme of dependence of damages on irradiation dose, which was different for different dose ranges. According to the scheme, the quantitative characteristics were similar for the doses that differed by several orders of magnitude; in a certain dose range, the effect may have an opposite sign.The results obtained and supported by numerous experiments are important because the above dose dependences made it possible to come to conclusion about a radiogenic or non-radiogenic character of changes observed in an irradiated organism. The indisputable conclusion that if the effect increases with the dose it is evidence for its radiogenic nature is by no means in favor of an opposite statement, i.e., that the absence of a direct dose–effect dependence but its nonmonotonic character is evidence for the absence of a relation of the effect to irradiation. The controversial conclusions of International and Russian organizations stem mainly from the underestimation and misunderstanding of the effects of ultra-low and low irradiation doses, reluctance to apply other criteria to assess the consequences of irradiation on human health, and conviction (groundless) that low doses cause either no damages or such minor damages that they may be neglected and disregarded. In the lecture, data that elucidate the above controversies will be presented.



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