All issues
Volume 50, Issue 6
Displaying 1-13 of 13 articles from this issue
- |<
- <
- 1
- >
- >|
Regular Papers
-
Takako YASUDA, Shoji ODA, Yuji ISHIKAWA, Tomomi WATANABE-ASAKA, Masayu ...2009 Volume 50 Issue 6 Pages 487-494
Published: 2009
Released on J-STAGE: December 04, 2009
Advance online publication: August 13, 2009JOURNAL FREE ACCESSTo observe the sequential radiation-induced apoptosis in a living embryo, we injected Acridine Orange (AO) solution into the yolk of embryo and visualized radiation-induced apoptosis in developing optic tectum (OT). Medaka embryos at stage 28, when neural cells proliferate rapidly in the OT, were irradiated with 5 Gy X-rays which is a non-lethal dose for irradiated embryos at hatching. The irradiated embryos hatched normally without morphological abnormalities in their brains, even though a large number of apoptotic cells were induced transiently in OT. By yolk injection, apoptotic cells in OT were distinguished as AO-positive small nuclei at 3 h after irradiation. At 8-10 h after irradiation, AO-positive rosette-shaped clusters were obviously distinguished in marginal tectal regions of OT where cells are proliferating intensely. The AO-positive clusters became bigger and more obvious, but the number did not increase up to 24 h after irradiation and completely disappeared up to 49 h after irradiation. This characteristic appearance of the AO-positive nuclei/clusters is in good agreement with our previous results, based on the examination of fixed specimens stained with AO by injection into the peri-vitelline space, suggesting that the AO-yolk injection method is highly reliable for detecting apoptotic cells in living embryos. The live imaging of apoptotic cells in developing Medaka embryos by AO-yolk injection method is expected to reveal more of the details of the dynamics of apoptotic responses in the irradiated brain and other tissues.View full abstractDownload PDF (1812K) -
Kazutaka DOI, Shinji TOKONAMI, Hidenori YONEHARA, Shinji YOSHINAGA2009 Volume 50 Issue 6 Pages 495-506
Published: 2009
Released on J-STAGE: December 04, 2009
Advance online publication: August 13, 2009JOURNAL FREE ACCESSIn most countries, radon is the dominant contributor among natural radiation sources to the radiation exposure dose of the general population. Numerous case-control studies of residential radon and lung cancer have been conducted using passive radon (Rn-222) detectors. These studies showed that radon may increase lung cancer risk, but most of them did not show a significant risk. Recently it was shown that the readings of passive radon detectors that do not employ thoron (Rn-220) discrimination techniques are affected by thoron. Therefore, we conducted a simulation study to evaluate the possible effect of thoron interference on the estimation of radon-related lung cancer risk. Various assumptions were made based on the number of cases, matching ratio, baseline risk, true radon-related risk, distribution of radon and thoron concentrations, correlation between radon and thoron, and radon detectors. The results suggested that in certain circumstances thoron interference in radon measurements resulted in an approximately 90% downward bias. In addition, the magnitude of the bias increased as the geometric mean and geometric standard error of radon concentration decreased and those of thoron increased. In order to resolve this problem, it is necessary to use passive radon detectors with thoron discrimination techniques in epidemiological studies.View full abstractDownload PDF (1362K) -
A Comparison of Mammographic X-ray Spectra: Simulation with EGSnrc and Experiment with CdTe DetectorKhatayut NIGAPRUKE, Patana PUWANICH, Nakorn PHAISANGITTISAKUL, Wiwat Y ...2009 Volume 50 Issue 6 Pages 507-512
Published: 2009
Released on J-STAGE: December 04, 2009
Advance online publication: August 21, 2009JOURNAL FREE ACCESSMammographic x-ray spectra simulated by BEAMnrc/EGSnrc Monte Carlo code were qualitatively compared with the results obtained from the direct measurement using a cadmium telluride x-ray spectroscopy system and from the generation of IPEM report number 78. Generally, there is good agreement between the simulated and measured spectra, though there are slight differences at low energy in which the K-characteristic x-ray intensity is relatively higher for IPEM spectra. In addition, transmission curves were measured and simulated using a breast tissue-equivalent phantom (BR-12) as filtration. Comparison of the transmission curves shows good agreement. Moreover, the first half value layer (HVL) from direct measurement using ion chamber was consistent with the first HVL calculated by simulated spectra. Therefore, Monte Carlo may be used as an alternative tool for obtaining x-ray spectra when direct measurement is not available.View full abstractDownload PDF (259K) -
Shinichiro MORI, Hsiao-Ming LU, John A. WOLFGANG, Noah C. CHOI, George ...2009 Volume 50 Issue 6 Pages 513-519
Published: 2009
Released on J-STAGE: December 04, 2009
JOURNAL FREE ACCESSIntrafractional motion and interfractional changes affect the accuracy of the delivered dose in radiotherapy, particularly in charged-particle radiotherapy. Most recent studies are focused on intrafractional motion (respiratory motion). Here, we report a quantitative simulation analysis of the effects of interfractional changes on water-equivalent pathlength (WEL) in charged-particle lung therapy. Serial four-dimensional (4D) CT scans were performed under free breathing conditions; the time span between the first and second 4DCT scans was five weeks. We quantified WEL changes between the first and second CT scans due to interfractional changes (tumor shrinkage and tissue density changes) and compared the particle-beam-stopping point between the serial 4DCT scans with use of the same initial bolus. Both tumor-shrinkage and lung-density changes were observed in a single patient over the course of therapy. The lung density decreased by approximately 0.1 g/cm3 between the first and second-CT scans, resulting in a 1.5 cm WEL changes. Tumor shrinkage resulted in approximately 3 cm WEL changes. If the same initial bolus and plan were used through the treatment course, an unexpected significant beam overshoot would occur by interfractional changes due to tumor shrinkage and lung density variation.View full abstractDownload PDF (1714K) -
Yuhui HAO, Rong LI, Yanbing LENG, Jiong REN, Jing LIU, Guoping AI, Hui ...2009 Volume 50 Issue 6 Pages 521-528
Published: 2009
Released on J-STAGE: December 04, 2009
Advance online publication: October 03, 2009JOURNAL FREE ACCESSPurpose: The aim of this study was to evaluate the potential genotoxicity induced by chronic oral exposure to depleted uranium (DU). Materials and methods: Weanling Wistar rats (F0), 50/sex/group, were exposed to DU in food at doses of 0, 4, or 40 mg kg-1day-1 for four months. They were subsequently mated, resulting in the birth of F1 rats. Fifty Fl weanlings/sex/group were exposed for four months to the same dose levels as their parents. After four months, the uranium content in the tissues, the potential damage to the genetic material, and pathomorphological changes of the testicles were observed in both F0 and F1 rats. The genotoxicity of DU was evaluated by the following methods: sperm abnormality assessment, the bone-marrow micronucleus test, and the comet assay. Results: Uranium content in F1 rats was significantly higher than that in F0 rats in both the kidney and ovary (p < 0.05). The sperm abnormality rate, marrow cell micronuclei rate, comet tail length, and tailed cell percentage increased in each treatment group in each generation compared with the control group (p < 0.05). When comparing F1 with F0 rats, significant differences were detected for most of the indicators, with F1 rats always exhibiting more damage (p < 0.05). With regard to pathomorphological changes in the testicles, the sperm displayed aty-pical changes, including thickening of the anachromasis nucleolus, which seemed to be more severe in F1 rats. Conclusion: Genotoxicity may be induced in rats after chronic oral exposure to a low dose of DU.View full abstractDownload PDF (1048K) -
Saeed UR-RAHMAN, Muhammad RAFIQUE, Matiullah, Javaid ANWAR2009 Volume 50 Issue 6 Pages 529-535
Published: 2009
Released on J-STAGE: December 04, 2009
JOURNAL FREE ACCESS
Supplementary materialSeasonal indoor radon measurement studies have been carried out in four districts, namely, Jhelum, Chakwal, Rawalpindi and Attock of the Punjab Province. In this regard, CR-39 based detectors were installed in bedrooms, drawing rooms and kitchens of 40 randomly selected houses in each district. After exposing to radon in each season, CR-39 detectors were etched in 6M NaOH at 80°C and counted under an optical microscope. Indoor radon activity concentrations in the houses surveyed ranged from 15 ± 4 to 176 ± 7 Bq m-3 with an overall average value of 55 ± 31 Bq m-3. The observed annual average values are greater than the world average of 40 Bq m-3. Maximum indoor radon concentration levels were observed in winter season whereas minimum levels were observed in summer season. None of the measured radon concentration value exceeded the action level of 200-400 Bq m-3. The season/annual ratios for different type of dwellings varied from 0.87 ± 0.93 to 1.14 ± 1.10. The mean annual estimated effective dose received by the residents of the studied area was found to be 1.39 ± 0.78 mSv. The annual estimated effective dose is less than the recommended action level (3-10 mSv).View full abstractDownload PDF (836K) -
Ernesto CRESCENTI, Máximo CROCI, Vanina MEDINA, Lorena SAMBUCO, ...2009 Volume 50 Issue 6 Pages 537-544
Published: 2009
Released on J-STAGE: December 04, 2009
Advance online publication: October 12, 2009JOURNAL FREE ACCESSIn this study we evaluated in vivo the tolerance induced by the combination of Se, Zn and Mn (4 μg/ml each) plus Lachesis muta venom (4 ng/ml) (O-LM) to high doses of ionizing radiation. The protective effect of O-LM was investigated on the small-intestine and bone marrow of mice irradiated with a single whole-body dose of 10 Gy employing a 137Cs source. Mice were sacrificed 3 days after irradiation. Mice receiving a subcutaneous daily O-LM injection starting 30 days before irradiation, showed a higher number of crypts, enhanced villous conservation and lack of edema or vascular damage in comparison to the untreated and irradiated group. In addition, O-LM treatment decreased vascular damage and the grade of aplasia preserving medullar progenies induced by ionizing radiation on mouse bone marrow. The protective effect of O-LM against radiation injury to the small intestine was associated with an increase in proliferation and a reduction of apoptosis in intestinal crypts and furthermore, to an enhanced intestinal immunoreactivity of MnSOD, and CuZnSOD, and also catalase. Based on the present results and taking into account that O-LM is being safely administered in phase I clinical trial as an immunomodulator, we suggest that O-LM could be an attractive candidate as a safe radioprotective agent for patients undergoing radiotherapy.View full abstractDownload PDF (1028K) -
Seung-Hee RYU, Soo Young MOON, Youn-Joo YANG, Sun Rock MOON, Joon Pio ...2009 Volume 50 Issue 6 Pages 545-552
Published: 2009
Released on J-STAGE: December 04, 2009
JOURNAL FREE ACCESSIrradiation causes the impaired proliferation of cells lining mucosal membranes. Epidermal growth factor (EGF) facilitates proliferation of various skin cells; however, the wound healing effects of EGF on radiation-damaged cells is less well known. To evaluate the effects of recombinant human EGF (rhEGF) on the proliferation of cells following irradiation, we tested two types of fibroblast cell lines and one keratinocyte cell line. The viable cell numbers were significantly increased by rhEGF treatment for 24 h immediately after 8 Gy of irradiation. The most effective dose of rhEGF was 10 nM in all cell lines used in this study. The percentage of BrdU-labeled cells was also significantly increased by rhEGF treatment. To evaluate the effects of rhEGF on radiation-induced oral mucosal damage in BALB/c mice, we systematically injected 1 mg/kg/day EGF for three days after 17 Gy of irradiation. Administered rhEGF ameliorated radiation-induced mucosal damage in vivo. rhEGF significantly increased the epithelial cell layer thickness and the proliferation of basal layer cells as detected by Ki-67 staining. Our results suggest that rhEGF can be a therapeutic treatment for radiation-induced wounds by stimulating the proliferation of fibroblasts and keratinocytes following irradiation.View full abstractDownload PDF (639K) -
Yong LIU, Kenji NAGATA, Shin-ichiro MASUNAGA, Minoru SUZUKI, Genro KAS ...2009 Volume 50 Issue 6 Pages 553-557
Published: 2009
Released on J-STAGE: December 04, 2009
Advance online publication: October 03, 2009JOURNAL FREE ACCESSPrevious studies have demonstrated that X-ray irradiation affects angiogenesis in tumors. Here, we studied the effects of γ-ray irradiation on boron-10 compound accumulation in a murine tumor model. The mouse squamous cell carcinoma was irradiated with γ-ray before BSH (10B-enriched borocaptate sodium) administration. Then, the boron-10 concentrations in tumor and normal muscle tissues were measured by prompt γ-ray spectrometry (PGA). A tumor blood flow assay was performed, and cell killing effects of neutron irradiation with various combinations of BSH and γ-rays were also examined. BSH concentrations of tumor tissues were 16.1 ± 0.6 μg/g, 16.7 ± 0.5 μg/g and 17.8 ± 0.5 μg/g at 72 hours after γ-ray irradiation at doses of 5, 10, and 20 Gy, compared with 13.1 ± 0.5 μg/g in unirradiated tumor tissues. The enhancing inhibition of colony formation by neutron irradiation with BSH was also found after γ-ray irradiation. In addition, increasing Hoechst 33342 perfusion was also observed. In this study, we demonstrated that γ-ray irradiation enhances BSH accumulation in tumors. The present results suggest that the enhancement of 10B concentration that occurs after γ-ray irradiation may be due to the changes in the extracellular microenvironment, including in tumor vessels, induced by γ-ray irradiation.View full abstractDownload PDF (986K) -
Deborshi BHATTACHARJEE, Alexander I. IVANNIKOV, Kassym ZHUMADILOV, Val ...2009 Volume 50 Issue 6 Pages 559-565
Published: 2009
Released on J-STAGE: December 04, 2009
Advance online publication: October 03, 2009JOURNAL FREE ACCESSElectron spin resonance (ESR) dosimetry of teeth is used extensively for dose estimation following exposure to radiation. The population inhabiting the northeast region of India is prone to different cancers of the head and neck, and their prevalence is several times the national average. The objective of this study was to determine the role of radiation in the causation of this high cancer incidence by performing ESR spectroscopic measurements of tooth samples collected from the general population living in and around the city of Silchar. Nineteen tooth samples were used, and the age of the patients was 13-60 years. The excess dose, determined by subtraction of the natural background dose from the dose absorbed by the enamel, was found to the extent of 123 ± 43 mGy. However, the individual excess dose was found to be higher in subjects who consumed lime (5/6) than in non-lime-consuming subjects (2/13). It is not entirely clear if radiation is the cause of this excess cancer in this region of India. Therefore there is a need for wider studies including consideration of tobacco consumption as well as a larger number of samples for tooth enamel dosimetry.View full abstractDownload PDF (440K)
Short Communications
-
Yi XIE, Hong ZHANG, Ji-Fang HAO, Rong QIU2009 Volume 50 Issue 6 Pages 567-571
Published: 2009
Released on J-STAGE: December 04, 2009
Advance online publication: August 21, 2009JOURNAL FREE ACCESSThe aims of present study are to estimate the biological risks to the immunity of mice exposed to heavy ion radiation and to investigate the effect of N-acetylcysteine (NAC) on 12C6+ ion irradiation-induced lymphocyte DNA damage. Results showed that in the brine group, the levels of lymphocyte DNA damage and MN, thymocytes G2/M phase arrest and apoptosis percentages (except for activity of NK cells) were up at each time point. A time-response curve for MN and DNA damage appeared in the NAC group. We found that whole-body 12C6+ ion irradiation at a dose of 4 Gy could: induce lymphocyte DNA double-strand breaks (DSBs); immunocytes DSBs may lead to acute effects on immunity; and 200 mg/kg NAC showed significant protection against radiation harm.View full abstractDownload PDF (458K) -
Yuji NAGAYAMA, Tatsuki ICHIKAWA, Ohki SAITOH, Norio ABIRU2009 Volume 50 Issue 6 Pages 573-577
Published: 2009
Released on J-STAGE: December 04, 2009
Advance online publication: September 16, 2009JOURNAL FREE ACCESSThe previous data regarding the effect of irradiation on thyroid autoimmunity are controversial. We have recently reported the exacerbation of autoimmune thyroiditis by a single low dose (0.5 Gy) of whole body irradiation in thyroiditis-prone non-obese diabetic (NOD)-H2h4 mice treated with iodine for 8 weeks. However, it is uncertain in that report whether the results obtained by the provision of iodine in a relatively short period of time (8 weeks) accurately reflects the long-term consequences of low-dose irradiation on thyroid autoimmunity. Therefore, we repeated these experiments with mice that were monitored after irradiation without iodine treatment for up to 15 months. We found that a single low-dose (0.5 Gy) irradiation increased the incidence and severity of thyroiditis and the incidence and titers of anti-thyroglobulin autoantibodies at 15 months of age. The numbers of splenocytes and percentages of various lymphocyte subsets were not affected by irradiation. Thus, we conclude that low-dose irradiation also exacerbates late-onset spontaneous thyroiditis in NOD-H2h4 mice; one plausible explanation for this may be the acceleration of immunological aging by irradiation.View full abstractDownload PDF (189K)
Miscellaneou
-
2009 Volume 50 Issue 6 Pages xxxiii-xlii
Published: 2009
Released on J-STAGE: December 04, 2009
JOURNAL FREE ACCESSDownload PDF (676K)
- |<
- <
- 1
- >
- >|