An increased systemic production of oxygen-free radicals by activated inflammatory cells is thought to be involved in the pathophysiology of asthma. The aim of this study is to evaluate the clinical effects of radon and thermal therapy on asthma in relation to antioxidant enzymes and lipid peroxide. Radon and thermal therapy were performed once a week. All subjects went to a hot bathroom with a high concentration of radon, and nasal inhalation of vapor from a hot spring was performed for 40 min once a day under conditions of high humidity. The room temperature was 48°C; the room radon concentration was 2,080 Bq/m³. Blood samples were collected at 2 h, 14, and 28 days after the first therapy. A blood sample also was collected before the first therapy (at body temperature and background radon level) to be used as the control. The forced expiratory volume in one second (%FEV₁) was significantly increased 28 days after the first therapy. On day 28, the catalase (CAT) activity was significantly increased in comparison with the control. The superoxide dismutase (SOD) activity was significantly increased compared to the control after first inhalation. On days 14 and 28, the lipid peroxide level was significantly decreased in comparison with the control. In conclusion, the present pilot study has shown that radon and thermal therapy improved the pulmonary function of asthmatics by increasing the reduced activities of antioxidant enzymes.

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The oral administration of Mentha extract (ME) before exposure to gamma radiation was found to be effective in increasing the frequency of radiation-induced endogenous spleen colonies. A significant increase in the weight of the spleen was observed in animals of the Mentha and radiation combined group in comparison to the irradiation-alone group on day 10 of postirradiation. Furthermore, a significant increase in the body weight of animals in the Mentha and radiation combined group was observed in all the radiation doses studied. A regression analysis of survival data yielded LD50/30 as 6.48 ± 0.07 and 11.59 ± 0.21 Gy for the irradiation-alone and the Mentha and radiation combined group, respectively, and produced a dose reduction factor (DRF) of 1.78. Significant increases in total erythrocyte and leucocyte counts, hemoglobin concentration, and hematocrit values were observed in the animals of the Mentha and radiation combined group in comparison to the hematological values observed in the irradiation-alone group at all radiation doses studied (6, 8, and 10 Gy). A dose-dependent decrease in reduced glutathione (GSH) content and an increase in lipid peroxidation (LPO) levels were observed in control animals. However, the animals of the Mentha and radiation combined group exhibited a significant increase in GSH content and a decrease in LPO level, but the values remained below normal. A significant increase in the serum alkaline phosphatase activity was observed in the animals of the Mentha and radiation combined group during the entire period of study, and normal range was evident at 24 h (6 Gy) and day 5 (8 Gy). However, this level could not be restored even at day 30 in 10 Gy exposed animals. Measured acid phosphatase activity in the animals of the Mentha and radiation combined group was found to be significantly lower than the respective controls and attained normal value at day 5 (6 and 8 Gy) and day 20 (10 Gy).

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To evaluate the effect of fermented milk kefir on X-ray-induced apoptosis in the colon of rats, we examined the apoptotic index, the mean number of apoptotic cells detected by H&E staining per crypt in the colon, in control rats and kefir-pretreated rats drinking kefir for 12 days before irradiation. Apoptotic cells were confirmed by TUNEL staining, and active caspase-3 expression was studied by immunohistochemistry. The cell position of apoptotic cells and active caspase-3 positive cells were examined. The apoptotic index of kefir-treated rats was significantly (p < 0.05) decreased 2 h after 1 Gy irradiation in comparison with control rats at crypt cell positions 1-3, 5-7, 13, and 15. Active caspase-3 expression in the kefir-treated rats was also significantly (p < 0.05) reduced in comparison with control rats 2 h after 1 Gy irradiation at crypt cell positions 1-4, 13, and 15. This study indicated that kefir protects colonic crypt cells against radiation-induced apoptosis, which was most pronounced in the stem cell region of the crypt. The antiapoptotic effect of fermented milk kefir was due to the inhibition of caspase-3 activation.

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Immediately after X-irradiation, monocytic cells can express the gene for interleukin (IL)-1β, which enhances inflammation and contributes to radioprotection in mice. In order to analyze the mechanism(s) for the immediate-early induction of IL-1β after X-irradiation at 20 Gy in cultured murine macrophages, we examined the molecules that bound to the DNA fragments corresponding to the upstream region of 10 kb of the mouse IL-1β gene using an electrophoretic mobility-shift assay. Three DNA fragments corresponding to the 8,500, 8,000 and 2,500 bases upstream of the gene showed an unique binding site with the nuclear extract. Specific binding activity with these DNA fragments was observed in the nuclear extract from non-irradiated cells, and disappeared upon a pretreatment of the extract with proteinase K. The binding activity was not detected in the nuclear extract from irradiated cells. This shows that protein(s) specifically binding to the far-upstream regions of the IL-1β gene disappear immediately after X-irradiation in the nuclei of macrophage cells, and that the event is potentially related to the immediate-early response of IL-1β gene expression.

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Lifetime bone tumor induction by the injection of a bone-seeking alpha emitter, ²³⁹Pu citrate, was compared among 630 female mice from three strains (C3H/He, C57BL/6 and B6C3F₁) showing different genetic backgrounds for carcinogenesis. Bone tumors, mostly osteosarcomas, appeared early during the period from 200 to 600 days after the injection, showing an almost similar dose responsiveness with a peak incidence of 50% to 63% at skeletal doses of 2-3 Gy, in all mouse strains. The primary sites of bone tumors from these strains were also predominantly distributed in 80% to 90% of the skeletal bones, which had well-developed trabecular bone surfaces and large vascular sinusoids. The frequency of lymphoid neoplasms was significantly lower than the control values, and some appeared earlier at the higher injected doses than those of the controls. Fewer or no myeloid leukemias were found in all the control and injected animals, and the incidences of other solid tumors decreased, reaching zero at doses where the maximum incidences of bone tumors were noted. These findings indicate that osteosarcoma is the only specific tumor commonly observed among different mouse strains following the injection of soluble plutonium compounds.

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Residual ¹⁵²Eu activities induced by neutrons from the Nagasaki atomic bomb were measured for nine mineral samples located up to 1,061 m in the slant range and one control sample at 2,850 m from the hypocenter. A chemical separation to prepare europium-enriched samples was performed for all samples, and gamma ray measurements were carried out with a low background well-type germanium detector. In this paper, the measured specific activities of ¹⁵²Eu are compared with activation calculations based on the DS86 neutron fluence and the 93Rev one. The calculated-to-measured ratios are also compared with those of ⁶⁰Co and ³⁶Cl. The present results indicate that the measurements agree to the calculation within a factor of three as observed in the nuclear tests at Nevada. The activation level of environmental neutrons and the detection limit for ¹⁵²Eu are also discussed.

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Concentrations of total folates and their oxidative degradate, para-aminobenzoyl glutamic acid, were determined in mouse after 2-7 Gy total body γ-irradiation (TBI). Total liver folate levels were drastically reduced by almost 47% over a period of 120 h after TBI with 7 Gy. Oxidative damage, splitting the folate molecule into pterin and p-aminobenzoylglutamic acid (p-ABG), was observed after TBI. p-ABG levels, which 24 h after irradiation were raised by 15%, were further elevated to more than three-fold over the control after 120 h. A dose-dependent increase in the oxidative degradation of folate was observed. The oxidative cleavage of folate may be one factor contributing to folate deficiency in radiation stress.

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Various chemical agents were examined for their radioprotective capability to provide partial protection against radiation injury over the past 50 years. However, no suitable drug has yet been introduced for routine clinical use. In the present study, the radioprotective potential of H2 receptor antagonists was examined in in vivo and in vitro conditions. For this purpose, an in vivo micronucleus assay and an in vitro metaphase analysis were used to test the effects of cimetidine, ranitidine, and famotidine on radiation-induced clastogenic effects. For micronuclei assay, Balb/c mice were irradiated in the presence or absence of drugs, and slides were prepared from bone marrow cells. The frequency of micronuclei was determined in bone marrow erythrocytes. For the in vitro assay, lymphocytes in whole peripheral blood were exposed to radiation in the presence or absence of drugs, and the frequency of chromosomal aberrations were determined. The results show that radiation produced a high number of micronuclei in polychromatic erythrocytes (PCE) and chromosomal aberrations in lymphocytes. All three drugs used in this study effectively reduced the frequency of radiation-induced micronuclei and chromosomal aberrations at various doses. Famotidine was found to be more effective than the other two drugs. From the results obtained, it can be concluded that H2-receptor antagonists reduced the clastogenic effects of radiation with a dose reduction factor (DRF) of 1.5-2 in vivo and in vitro. The way in which these drugs reduce the clastogenic effects of radiation might be via a radical scavenging mechanism.

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The effect of wortmannin posttreatment was studied in cells derived from different species (hamster, mouse, chicken, and human) with normal and defective DNA-dependent protein kinase (DNA-PK) activity, cells with and without the ataxia telangiectasia (ATM) gene, and cells lacking other regulatory proteins involved in the DNA double-strand break (DSB) repair pathways. Clonogenic assays were used to obtain all results. Wortmannin radiosensitization was observed in Chinese hamster cells (V79-B310H , CHO-K1), mouse mammary carcinoma cells (SR-1), transformed human fibroblast (N2KYSV), chicken B lymphocyte wild-type cells (DT40), and chicken Rad54 knockout cells (Rad54^-/-). However, mouse mammary carcinoma cells (SX9) with defects in the DNA-PK and chicken DNA-PK catalytic subunit (DNA-PKcs) knockout cells (DNA-PKcs^-/-/-) failed to exhibit wortmannin radiosensitization. On the other hand, SCID mouse cells (SC3VA2) exposed to wortmannin exhibited significant increases in radiosensitivity, possibly because of some residual function of DNA-PKcs. Moreover, the transformed human cells derived from AT patients (AT2KYSV) and chicken ATM knockout cells (ATM^-/-) showed pronounced wortmannin radiosensitization. These studies demonstrate confirm that the mechanism underlying wortmannin radiosensitization is the inhibition of DNA-PK, but not of ATM, thereby resulting in the inhibition of DSB repair via nonhomologous endjoining (NHEJ).

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Radiation-induced polymerization of vinylbenzyltrimethylammonium chloride (VBT) in aqueous solution has been investigated by steady-state and pulse radiolysis techniques. The effects of dose, dose rate, monomer concentration, pH, and ambient conditions on steady state polymerization were investigated. The reactions of primary radicals of water radiolysis, such as OH radical, e^-_aq, and H atom, were studied. The reactions of other chemically active species such as O^·-, oxidizing radicals such as N₃^·, Cl₂^·-, Br^2·-, SO₄ ^·-, and a reducing specie such as CO₂^·- with VBT were also investigated. The reaction of VBT with OH radical and H atom were investigated by formation kinetics and by competition kinetics. The rate constant values for the reaction of OH radical with VBT were 4.7 ¤ 10⁹ dm³ mol^-1 s ^-1 and 1.7 ¤ 10¹⁰ dm³ mol ^-1 s^-1 by formation kinetics and by competition kinetics, respectively. The results indicate that OH radicals undergo electron transfer reactions (resulting in a radical cation) and addition reactions. The hydrated electron reacts with VBT with a rate constant of 1.9 ¤ 10¹⁰ dm³ mol ^-1 s^-1 to form an anion. At pH ~1, H atom reaction with VBT is diffusion controlled with a rate constant of 5.1 ¤ 10⁹ dm³ mol^-1 s ^-1 as determined by formation kinetics and 1.7 × 10 ¹⁰ dm³ mol^-1 s^-1 as determined by competition kinetics. VBT radical anion reacts with VBT at a rate that is almost twice the rate at which VBT radical cation reacts with VBT, indicating anionic initiation of the polymerization of VBT. VBT undergoes very fast steady-state polymerization and dose rate; the presence of efficient radical quenchers such as oxygen and concentration of VBT in the aqueous solution affects the extent of polymerization. Typically, a dose of 4 kGy is sufficient to achieve 80-85% polymerization. The monomer solution shows a drastic increase in the viscosity of the solution, which finally gels to a soft rubbery mass.

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The relative biological effectiveness (RBE) of various energy neutrons produced from a Schenkel-type accelerator at the Research Institute for Radiation Biology and Medicine, Hiroshima University (HIRRAC), compared with 60Co gamma-ray radiation was determined. The neutron radiations and gamma-ray radiation produced good linear changes in the frequency of micronuclei induced in the root-tip cells of Allium cepa onion irradiated as dry dormant seeds (seed assay) and seedlings (seedling assay) with varying radiation doses. Therefore the RBE for radiation-induced micronuclei can be calculated as the ratio of the slopes of the fitted linear dose response for the neutron radiations and the 60Co gamma-ray radiation. The RBE values by seed assay and seedling assay decreased to 174 7, from 216 9, and to 31.4 1.0, from 45.3 1.3 (one standard error), respectively, when neutron energies increased to 1.0 MeV, from 0.2 MeV, in the present study. Furthermore, the ratio of the micronucleus induction rates of seed assay to seedling assay by gamma-ray radiation was much lower than that by neutron radiations.

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The effects of X-rays on cell survival, apoptosis, and long-term response in the development of cell death as measured by the dye exclusion test were studied in human leukemic MOLT-4 cells (p53 wild-type) stably transfected with a mutant p53 cDNA expression vector. Cell survival, as determined from colony-forming ability, was increased in an expression level dependent manner, but the increase was partial even with the highest-expressing clone (B3). This contrasts with the prior observation that cell death and apoptosis in B3 are completely inhibited at 24 h after irradiation with 1.8 Gy of X-rays1). The examination of B3 cells incubated for longer than 24 h after X-irradiation showed a delay in the induction of cell death and apoptosis. Western blot analysis revealed that the time required to reach the highest level of wild-type p53 protein in B3 was longer than the time in MOLT-4 and that the p53 may be stabilized by the phosphorylation at Ser-15. These results suggest that the introduction of mutant p53 into MOLT-4 merely delays the development of apoptosis, during which the cells could repair the damage induced by X-rays, and results in the partial increase in cell survival.

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A new method was developed to analyze urinary 8-hydroxydeoxyguanosine (8-OH-dG) by high-performance liquid chromatography (HPLC) coupled to an electrochemical detector (ECD). This method is unique because (i) urine is first fractionated by anion exchange chromatography (polystyrene-type resin with quaternary ammonium group, sulfate form) before analysis by reverse phase chromatography; and (ii) the 8-OH-dG fraction in the first HPLC is precisely and automatically collected based on the added ribonucleoside 8-hydroxyguanosine marker peak, which elutes 4-5 min earlier. Up to 1,000 human urine samples can be continuously analyzed with high accuracy within a few months. This method will be useful for studies in radiotherapy, molecular epidemiology, risk assessment, and health promotion.

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