These proceedings aim to promote the understanding of the health hazard of radiation at low dose range and to construct a more solid basis for radiation safety policy. Radiation hazard has been the central issue of investigation in the field of radiation research. The two major approaches are mechanistic analysis by laboratory investigation and phenomenological analysis of radiation-exposed population as represented by epidemiology. In an increasingly safety-conscious society, the extremely low level risk associated with low dose of radiation has become an important issue. In this area, the phenomenological approach has a limit. DNA damage is the primary and direct cause of the risk. Tremendous progress has been made recently in the basic understanding of radiation effects on cells and tissues and the importance of damage response rather than damage itself. This challenges the classical linear non-threshold hypothesis.
Table of Contents
Epidemiological findings of radiation carcinogenesis.
Risk estimates for fast neutrons and implications for radiation protection (A.M. Kellerer). Gaps in the epidemiology of in utero radiation-exposure effects (R.E. Shore). Do the findings on the health effects of prolonged exposure to very high levels of natural radiation contradict current ultra-conservative radiation protection regulations? (S. M. J. Mortazavi, M. Ghiassi-Nejad, T. Ikushima). Where are the radon-induced lung cancer cases? Is it time for a re-evaluation of the radon problem? (A. Enflo). Investigation of cancer mortality in the Gastein Valley, an area of high-level natural radiation (J. Pohl-R¨ling, W. Hofmann). Prevalence of lung cancer and indoor radon in Thailand (S. Bovornkitti). ICRP evolutionary recommendations and the reluctance of the members of the public to carry out remedial work against radon in some high-level natural radiation areas (P.A. Karam et al.). Some correlation aspects of thyroid cancer epidemiology in Ukraine after Chernobyl accident (N.P. Dikiy et al.). Radiation risks of leukemia incidence among Russian emergency workers, 1986-1997 (V. Ivanov et al.). Fallout exposure in the Semipalatinsk Nuclear Test Site area and the induction of thyroid nodules diseases (Z.H. Zhumadilov et al.). The mortality and cancer morbidity experience of workers at British Nuclear Fuels plc, 1946-1997 (D. McGeoghegan, K. Binks). European Commission's research programme related to the health effects of ionizing radiation (C. Desaintes, D. Teunen). Does radiation cause liver cancer? Comparison of radiation effects in atomic-bomb survivors and other populations (G.B. Sharp). Radiosensitivity and expression of nucleotide excision repair genes in peripheral blood mononuclear cells of myelodysplastic syndrome patients (S. Ban et al.). An analysis of persistent inflammation among atomic bomb survivors with respect to sex and age at the time of the bombings (K. Neriishi, E. Nakashima). Basic study on the radon effects and the thermal effects in radon therapy (K. Yamaoka et al.).
Low dose radiation carcinogenesis.
Methodological aspects of low-dose epidemiological studies (C.R. Muirhead). Recent advances of "Epidemiological study in high background radiation area in Yangjiang, China" (L-X. Wei, T. Sugahara). Induction of myeloid leukemias in C3H/He mice with low-dose rate irradiation (T. Furuse, Y. Noda, H. Otsu). Dose and dose rate effect in mutagenesis, teratogenesis and carcinogenisis (T. Nomura). Spontaneous tumorigenesis and mutagenesis in mice defective in the MTH1 gene encoding 8-oxo-dGTPase (T. Tsuzuki et al.). Spontaneous and radiation-induced tumorigenesis in p53 deficient mice (R. Baskar et al.). Oncogenes and tumor suppressor genes in murine tumors induced by neutron or gamma-irradiation in utero (S. Antal et al.). Low dose fetal irradiation, chromosomal instability and carcinogenesis in mouse (P. Uma Devi, M. Hossain, M. Satyamitra). Effects of radioactive iodine (131I) on the thyroid of newborn, pubertal and adult rats (Y. Nitta, M. Hoshi, K. Kamiya). Modeling carcinogenic effects of low doses of inhaled radionuclides (I. Balásházy, W. Hofmann, A. Dam). Effects of a cell phone radiofrequency (860 MHz) on the latency of brain tumors in rats (B.C. Zook, S.J. Simmens).
Molecular analysis of radiogenic tumors: experimental.
Genetic analysis of radiation induced thymic lymphoma (R. Kominami et al.). Genetic analysis of radiation-induced mouse hepatomas (K. Kamiya et al.). Development and molecular analysis of thymic lymphomas induced by ionizig radiation in Scid mice (T. Ogiu et al.). Second hit of Tsc2 gene in radiation induced renal tumors of Eker rat model (O. Hino, H. Mitani, J. Sakaurai). PTCH (patched) and XPA genes in radiation-induced basal cell carcinomas (F.J. Burns et al.). Differences of molecular alteration between radiation-induced andN-ethyl-N-nitrosourea-induced thymic lymphomas in B6C3F1 mice (S. Kakinuma et al.).
Molecular analysis of radiogenic tumors: human.
Transgenic murine models of human cancer: bridging the gap from mouse to man (J.-L. Luo et al.). Cancers induced by alpha particles from Thorotrast (Y. Ishikawa, I. Wada, M. Fukumoto). The p53 andM6P/IGF2r genes of Thorotrast- and atomic bomb-induced liver cancers: a glimpse into the mechanisms of radiation carcinogenesis (K.S. Iwamoto). Molecular epidemiology of childhood thyroid cancer around Chernobyl (S. Yamashita et al.). Molecular analysis of radiation-induced thyroid carcinomas in humans (H.M. Rabes). Influence of XPD variant alleles on p53 mutations in lung tumors of nonsmokers and smokers (S.-M. Hou et al.). Genetic instability in thorotrast induced liver cancers (D. Liu et al.).
Molecular and cellular mechanism of radiation responses.
Transmission of damage signals from irradiated to nonirradiated cells (J.B. Little et al.). Specific gene expression by extremely low-dose ionizing radiation which related to enhance proliferation of normal human diploid cells (M. Watanabe, K. Suzuki, S. Kodama). The yin and yan of bystander versus adaptive response: lessons from the microbeam studies (H. Zhou et al.). Deficient PCNA expression and radiation sensitivity (G.E. Woloschak, T. Paunesku, M. Protic). Mutation induction by continuous low dose rate gamma irradiation in human cells (J. Kiefer, M. Kohlpoth, M. Kuntze). DNA-PK activity plays a role on radioadaption for radiation-induced apoptosis (T. Ohnishi, A. Takahashi, K. Ohnishi). The responses of the haemopoietic system to ionizing radiation (E.G. Wright). Does radiation enhance promotion of already-initiated cells in protracted high-LET carcinogenesis via a bystander effect? (S.B. Curtis et al.). A pulsed laser generated soft X-ray source for the study of gap junction communication and 'bystander' effects in irradiated cells (R.A. Meldrum et al.). Induction of radioresistance by a nitric oxide-mediated bystander effect (H. Matsumoto et al.). Roles of protein kinase C in radiation-induced apoptosis signaling pathways in murine thymic lymphoma cells (3SBH5 cells) (T. Nakajima et al.). Cellular mechanisms of radiation adaptive response in cultured glial cells (Y. Miura, K. Abe, S. Suzuki). Radiation-induced genomic instability and delayed activation of p53 (K. Suzuki, S. Kodama, M. Watanabe). Unstable nature of the X-irradiated human chromosome in unirradiated mouse m5S cells (S. Kodama et al.). Delayed cell-cycle arrest following heavy-ion exposure (S. Goto et al.) Analysis of radiation-inducible hSNK gene in human thyroid cells (Y. Shimizu-Yoshida et al.). Cellular response in normal human cells exposed to chronically low-dose radiation in heavy-ion radiation field (M. Suzuki et al.). Inhibition of radiation-induced DNA-double strand break repair by various metal/metalloid compounds (S. Takahashi et al.). Induction of a large deletion in mitochondrial genome of mouse cells by X-ray irradiation (T. Ikushima et al.) Effects of increased telomerase activity on radiosensitive human SCID cells (Y. Arase et al.). Protein synthesis, cellular defence and hprt-mutations induced by low dose neutron irradiation (A. Dám et al.). Enhanced induction of mutation by X-irradiation in Werner syndrome cells (G. Kashino et al.). An ESR and ESEEM study of long-lived radicals which cause mutation in irradiated mammalian cells (J. Kumagai et al.). A role of long-lived radicals in radiation mutagenesis and its suppression by epigallocatechin gallate (T. Ise et al.). Low dose of wortmannin reduces radiosensitivity of cells (K. Okaichi et al.). Defective accumulation of p53 protein in X-irradiated human tumor cells with low proteasome activity (M. Yamauchi et al.). High susceptibility and possible involvement of telonomic instability in the induction of delayed chromosome aberrations by X-irradiation in scid mouse cells (A. Urushibara et al.). Possible role of ATM-dependent pathway in phosphorylation of p53 in senescent normal human diploid cells (M. Suzuki et al.). Suppressive effects of p53 protein on heat-induced centrosomal abnormality (M. Miyakoda et al.). Susceptibility of calcium-deficient hydroxyapatite-collagen composite to irradiation (M. Ohta, M. Yasuda, H. Okamura). RBE values and dose rate effects on the ratio of translocation to dicentrics yields in neutrons with low-energy spectrum (K. Tanaka, N. Gajendiran, M. Mohankumar). Antioxidants as radioprotecting agents for low-level irradiation (E.B. Burlakova et al.).
Intestinal metaplasia induced by X-irradiation: its biological characteristics (H. Watanabe). Aberrant extracellular signaling induced by ionizing radiation and its role in carcinogenesis (R.L. Henshall-Powell, C.C. Park, M.H. Barcellos-Hoff). Apoptosis induced in small intestinal crypts by low doses of radiation protects the epithelium from genotoxic damage (C.S. Potten). Radiation-induced apoptosis and its role in tissue response (J.H. Hendry). Essential role of p53 gene in apoptotic tissue repair for radiation-induced teratogenic injury (T. Norimura, F. Kato, S. Nomoto).
Individual differences in chromosomal radiosensitivity: implications for radiogenic cancer (D. Scott). Susceptibility loci for radiation lymphomagenesis in mice (N. Mori, M. Okumoto). Age dependence of susceptibility for long-term effects of ionizing radiation (S. Sasaki). Nutrition status and radiation-induced of cancer in mice (K. Yoshida et al.). Mutations in cervical cancer as predictive factors for radiotherapy (K.M.Y. Wani et al.). Lectin staining as a predictive test for radiosensitivity of oral cancers (P. Remani et al.). Small dose pre-irradiation induced radioresistance and longevity after challenging irradiation in splenectomized C57BL/6 mice (K. Horie et al.). Suppression of X-ray-induced apoptosis by low dose pre-irradiation in the spleen of C57BL/6 mice (M. Yonezawa et al.). Effect of pre-irradiation of mice whole-body with X-ray on radiation-induced killing, induction of splenic lymphocyte apoptosis and expression of mutated Ca2+ channelα1A subunit (K. Sawada et al.). Elevation of antioxidants in the kidneys of mice by low-dose irradiation and its effect on Fe3+-NTA-induced kidney damage (T. Nomura, K. Yamaoka, K. Sakai). Suppressive effect of long-term low-dose rate gamma-irradiation on chemical carcinogenesis in mice (K. Sakai et al.). Possible role of elevation of glutathione in acquisition of enhanced immune function of mouse splenocytes exposed to low-dose γ-rays (S. Kojima et al.). Radiation protection effect on Hatakeshimeji (lyophyllum decastes sing) (Y. Gu et al.).
Molecular mechanisms of radiation carcinogenesis and their implications in radiation policy (J.B. Little, T. Sugahara).