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Volume 51 (2010)
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Volume 51, Issue 6
Displaying 1-18 of 18 articles from this issue
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Regular Papers
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Takuya KAMINUMA, Yoshiyuki SUZUKI, Katsuyuki SHIRAI, Toshiyuki MIZUI, ...2010 Volume 51 Issue 6 Pages 627-631
Published: 2010
Released on J-STAGE: November 23, 2010
Advance online publication: October 06, 2010JOURNAL FREE ACCESSThe direct biological effects of radiation, particularly accelerated heavy particle ions, on neurons are not fully known. Hence, the direct effect of carbon-ion beams on immature neurons was investigated by comparing to the effect of X-rays in vitro using primary hippocampal neurons. Primary neurons were prepared from hippocampi of fetal rats at embryonic day 18 from timed pregnant Wistar rats and cultured with Banker's methods. At 7 Days In Vitro (DIV), the cells were irradiated with 140 kV X-ray and 18.3 MeV/amu carbon-ion beams (LET = 108 keV/μm). The cells were fixed with 4% paraformaldehyde at 12 hours after irradiation. Then, the cells were treated with terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) and DAPI staining for measuring the percentage of apoptosis (apoptotic index: AI). AI in sham-irradiated hippocampal neurons was 18%. The value of AI (AIs) of the cells irradiated with X-rays at 10 or 30 Gy were 15% or 23%, respectively. AI in cells irradiated with carbon-ion beams at 1 Gy, 3 Gy, 5 Gy and 10 Gy were 22%, 23%, 24% and 33%, respectively. AI was significantly increased by carbon-ion beams at 10 Gy (p < 0.001). The apoptosis of hippocampal neurons increased in a dose-dependent manner following both X-ray and carbon-ion beams irradiation. Carbon-ion beams were about 10-fold more effective than X-rays for apoptosis induction in immature hippocampal neurons.View full abstractDownload PDF (458K) -
Veerle VANDERSICKEL, Julie DEPUYDT, Bram VAN BOCKSTAELE, Gianpaolo PER ...2010 Volume 51 Issue 6 Pages 633-641
Published: 2010
Released on J-STAGE: November 23, 2010
JOURNAL FREE ACCESSA better understanding of the underlying mechanisms of DNA repair after exposure to ionizing radiation represents a research priority aimed at improving the outcome of clinical radiotherapy. Because of the close association with DNA double strand break (DSB) repair, phosphorylation of the histone H2AX protein (γH2AX), quantified by immunodetection, has recently been used as a method to study DSB induction and repair at low and clinically relevant radiation doses. However, the lack of consistency in literature points to the need to further validate the role of H2AX phosphorylation in DSB repair and the use of this technique to determine intrinsic radiosensitivity. In the present study we used human mammary epithelial MCF10A cells, characterized by a radiosensitive phenotype due to reduced levels of the Ku70 and Ku80 repair proteins, and investigated whether this repair-deficient cell line displays differences in the phosphorylation pattern of H2AX protein compared to repair-proficient MCF10A cells. This was established by measuring formation and disappearance of γH2AX foci after irradiating synchronized cell populations with 60Co γ-rays. Our results show statistically significant differences in the number of γH2AX foci between the repair-deficient and -proficient cell line, with a higher amount of γH2AX foci present at early times post-irradiation in the Ku-deficient cell line. However, the disappearance of those differences at later post-irradiation times questions the use of this assay to determine intrinsic radiosensitivity, especially in a clinical setting.View full abstractDownload PDF (1221K) -
Sook In CHUNG, Jinsil SEONG, Young Nyun PARK, Won Woo KIM, Hae Jin OH, ...2010 Volume 51 Issue 6 Pages 643-650
Published: 2010
Released on J-STAGE: November 23, 2010
JOURNAL FREE ACCESSRadiation therapy (RT) has been emerging as one of the palliative treatments for locally advanced hepatocellular carcinoma (HCC). However, hepatic toxicity is a major obstacle in radiotherapy for HCC. The purpose of this study is to identify proteins indicating radiation-induced hepatic toxicity in cirrhotic rats, which can be used as possible biomarkers. Liver cirrhosis was induced in Wistar rats with thioacetamide (TAA) 0.3 g/L in drinking water for 9 weeks. The development of liver cirrhosis was observed histologically. Radiation hepatic injury was induced by treating 1/3 of the liver with 10 Gy single dose radiation. To find out commonly expressed proteins, liver tissue and serum were analyzed using two-dimensional electrophoresis and quadrupole time of flight mass spectrometry. Identified proteins were validated using western blotting. Histological examination showed that the degree of hepatic fibrosis increased by radiation in liver cirrhosis. It was associated with a decrease in the proliferation of cell nuclear antigen and an increase of apoptosis. The proteomic analysis of liver tissue and serum identified 60 proteins which showed significant change in expression between the TAA-alone and TAA-plus-radiation groups. Among these, an increase of heparanase precursor and decrease of hepatocyte growth factor were shown commonly in liver tissue and serum following radiation. Hepatic fibrosis increased following radiation in cirrhotic rats. These proteins might be useful in detecting and monitoring radiation-induced hepatic injury.View full abstractDownload PDF (1075K) -
Hao CHEN, Fanghua LI, Hang YUAN, Xiang XIAO, Gen YANG, Lijun WU2010 Volume 51 Issue 6 Pages 651-656
Published: 2010
Released on J-STAGE: November 23, 2010
JOURNAL FREE ACCESSThe mutagenic effects of low-energy ions have been identified by genetic studies for decades. Due to the short penetration distance of ions, however, the underlying mechanism(s) is still not quite clarified. Recently, increasing data have been accumulated concerning the existence and manifestation of radiation induced bystander/abscopal effects in vivo in the whole-organism environment. In this study, the bio-effects and the preliminary mechanisms of low energy ion beam irradiation on Medicago truncatula were investigated. The results show that both development and biochemical parameters, such as seed germination, seedling, superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD) were significantly affected by ion beam irradiation. It was also found that ion beam irradiation significantly increased the ROS generation and DNA strand breaks in Medicago truncatula. To further investigate the mechanism(s) underlying the responses, seeds were treated with dimethyl sulfoxide (DMSO), an effective reactive oxygen species (ROS) scavenger, and the results showed that DMSO treatment effectively rescued the seed germination and seedling rates and the morphological parameters of development, suggesting that ROS might play an essential role in the mechanisms of the bio-effects of ion-beam irradiated Medicago truncatula.View full abstractDownload PDF (701K) -
Viann Wing Yan CHOI, Teruaki KONISHI, Masakazu OIKAWA, Hiroyuki ISO, S ...2010 Volume 51 Issue 6 Pages 657-664
Published: 2010
Released on J-STAGE: November 23, 2010
JOURNAL FREE ACCESSIn the studies reported here, a high-linear-energy-transfer (high-LET)-radiation dose was used to induce adaptive response in zebrafish embryos in vivo. Microbeam protons were used to provide the priming dose and X-ray photons were employed to provide the challenging dose. The microbeam irradiation system (Single-Particle Irradiation System to Cell, acronym as SPICE) at the National Institute of Radiological Sciences (NIRS), Japan, was employed to control and accurately quantify the number of protons at very low doses, viz., about 100 μGy. The embryos were dechorionated at 4 h post fertilization (hpf) and irradiated at 5 hpf by microbeam protons. For each embryo, ten irradiation points were arbitrarily chosen without overlapping with one another. To each irradiation point, 5, 10 or 20 protons each with an energy of 3.4 MeV were delivered. The embryos were returned back to the incubator until 10 hpf to further receive the challenging exposure, which was achieved using 2 Gy of X-ray irradiation, and then again returned to the incubator until 24 hpf for analyses. The levels of apoptosis in zebrafish embryos at 25 hpf were quantified through terminal dUTP transferase-mediated nick end-labeling (TUNEL) assay, with the apoptotic signals captured by a confocal microscope. The results revealed that 5 to 20 protons delivered at 10 points each on the embryos, or equivalently 110 to 430 μGy, could induce radioadaptive response in the zebrafish embryos in vivo.View full abstractDownload PDF (514K) -
Atsushi ITO, Hisako NAKANO, Kunio SHINOHARA2010 Volume 51 Issue 6 Pages 665-673
Published: 2010
Released on J-STAGE: November 23, 2010
Advance online publication: October 20, 2010JOURNAL FREE ACCESSThe sensitizing effects of wild-type p53 on X-ray-induced cell death and on heat-induced apoptosis in M10, a radiosensitive and Trp53 (mouse p53 gene)-mutated lymphoma cell line which dies through necrosis by X-irradiation, were investigated using three M10 derived transfectants with wild-type TP53 (human p53 gene). Cell death was determined by colony formation and/or dye exclusion test, and apoptosis was detected as the changes in nuclear morphology by Giemsa staining. Expression of wild-type p53 protein increased radiosensitivity of cell death as determined by both clonogenic and dye exclusion assays. This increase in radiosensitivity was attributable largely to apoptosis induction in addition to a small enhancement of necrosis. Interestingly neither pathway to cell death was accompanied by caspase-3 activation. On the other hand, heat-induced caspase-3 dependent apoptotic cell death without transfection was further increased by the transfection of wild-type p53. In conclusion, the introduction of wild-type p53 enhanced apoptotic cell death by X-rays or heat via different mechanisms that do or do not activate caspase-3, respectively. In addition, p53 also enhanced the X-ray-induced necrosis in M10 cells.View full abstractDownload PDF (889K) -
Arturas INCIURA, Vydmantas ATKOCIUS, Elona JUOZAITYTE, Daiva VAITKIENE2010 Volume 51 Issue 6 Pages 675-681
Published: 2010
Released on J-STAGE: November 23, 2010
JOURNAL FREE ACCESSIn this report we update our long-term follow-up results of the prospective study whose aim was to evaluate the efficacy of high-dose-rate (HDR) brachytherapy in combination with external-beam radiotherapy (EBRT) in the treatment of medically inoperable endometrial cancer. Between 1995 and 1998, 29 patients with stages I-III medically inoperable carcinoma of endometrium were treated with definitive irradiation. All patients underwent combined intracavitary HDR brachytherapy and EBRT. The EBRT dose was 50 Gy with midline shield from 16 Gy. The HDR brachytherapy dose was 50 Gy, delivered in 5 fractions in a weekly schedule. Overall survival (OS) at 5 and 10 years was 48.3% and 20.7%, respectively. Disease-specific survival (DSS) at 5 and 10 years was 73.5% and 67.9%, respectively. The 10-year DSS rate was 73.5% for all stages, 85.7% for Stage I disease, 71.4% for Stage II, and 16.7% for stage III disease. Late Grade 1–2 radiation complications were observed in 4 patients (13.8%). Our long-term follow-up confirms that HDR brachytherapy with EBRT appears to be an effective and safe treatment for stage I and II medically inoperable endometrial cancer.View full abstractDownload PDF (428K) -
Gen SUZUKI, Ichiro YAMAGUCHI, Hiromitsu OGATA, Hideo SUGIYAMA, Hidenor ...2010 Volume 51 Issue 6 Pages 683-689
Published: 2010
Released on J-STAGE: November 23, 2010
Advance online publication: October 06, 2010JOURNAL FREE ACCESSIn two previous nation-wide surveys in the late 1980s and early 1990s, Japanese indoor radon concentrations increased in homes built after the mid 1970s. In order to ascertain whether this trend continued, a nation-wide survey was conducted from 2007 to 2010. In total 3,900 houses were allocated to 47 prefectures by the Neyman allocation method and 3,461 radon measurements were performed (88.7% success). The fraction of reinforced concrete / concrete block buildings was 32.4%, similar to the value from national statistics. Arithmetic mean (standard deviation, SD) and geometric mean (geometric SD) of radon concentration after adjusting for seasonal fluctuation were 14.3 (14.7) and 10.8 (2.1) Bq/m3. The corresponding population-weighted values were 13.7 (12.3) and 10.4 (2.0) Bq/m3, respectively. It was estimated that only 0.1% of dwellings exceed 100 Bq/m3, a new WHO reference level for indoor radon. Radon concentrations were highest in houses constructed in the mid 1980s and decreased thereafter. In conclusion, arithmetic mean indoor radon in the present survey was slightly lower than in previous surveys and significant reductions in indoor radon concentrations in both wooden and concrete houses can be attributed to alterations in Japanese housing styles in recent decades.View full abstractDownload PDF (995K) -
Tetsuo SAITO, Takashi SAKAMOTO, Natsuo OYA2010 Volume 51 Issue 6 Pages 691-698
Published: 2010
Released on J-STAGE: November 23, 2010
Advance online publication: October 06, 2010JOURNAL FREE ACCESSThis study aimed to identify factors predictive of the benefit of respiratory-gated radiotherapy. Three plans were created for 25 patients with non-small cell lung cancer, simulating the following 3 treatment scenarios. Protocol 1 was non-gated and the lung dose was calculated using 4-s slow CT (PnA), protocol 2 was also non-gated and the lung dose was calculated by CT at the end-expiration phase (PnE), and protocol 3 applied phase-based gating around end-expiration (PgE). We correlated possible predictive factors with the estimated lung dose reduction achieved by respiratory gating. The 3D clinical target volume (CTV) motion, craniocaudal CTV motion, and the craniocaudal CTV position were correlated with the reduction in V20 and the mean lung dose (p < 0.01). CTV was not significantly correlated with the estimated lung dose reduction. The area under the ROC curve (AUC) for 3D- and craniocaudal CTV motion, and craniocaudal CTV position was 1.000, 0.997, and 0.943, respectively, when the threshold for selecting patients was set at a 1% reduction of V20 and at a 0.5 Gy reduction in the mean lung dose. The results of the present study suggest that 3D CTV motion, craniocaudal CTV motion, and the craniocaudal CTV position are useful for predicting the benefit of respiratory-gated radiotherapy in lung cancer patients.View full abstractDownload PDF (1056K) -
Munetaka MATOBA, Tamaki KONDOU, Takuji TANAKA, Masataka KITADATE, Kiyo ...2010 Volume 51 Issue 6 Pages 699-705
Published: 2010
Released on J-STAGE: November 23, 2010
Advance online publication: October 23, 2010JOURNAL FREE ACCESSThe purpose of this study was to evaluate the usefulness of high-resolution MRI (HR-MRI) and proton MR spectroscopy (1H-MRS) for monitoring the early therapeutic response to radiotherapy. Twenty rabbits with VX2 carcinoma were divided into control (n = 8) and irradiation (n = 12) groups. The irradiation group underwent HR-MRI and 1H-MRS using a microscopy coil at 1, 3, 7 or 14 days after irradiation. Rabbits in the control group were subjected to HR-MRI and 1H-MRS at the same time intervals. All rabbits were killed after imaging and subjected to histopathologic examinations. The diameter of necrosis by HR-MRI was then compared to that on the gross specimens. The ratios of choline/creatine (Cho/Cr) and lactate/creatine (Lac/Cr) on the tumor and necrotic area detected by in vivo 1H-MRS were compared between the control and irradiation groups, respectively. In addition, the ratios of Cho/Cr and Lac/Cr were compared between the tumor and necrotic area in each irradiation group. A significant correlation was found between the diameter of necrosis in each sequence of HR-MRI and that in the gross specimens (r = 0.84–0.91, p = 0.03– < 0.003). The ratios of Lac/Cr in the tumors of the irradiation groups were significantly higher than those in the control groups after 1 day and 3 days of irradiation (p = 0.04, and p = 0.02). Histological analysis showed necrosis and swelling of the endothelia of capillaries and arterioles at 1 day and 3 days after irradiation. It was suggested that HR-MRI and 1H-MRS are useful methods for monitoring the early therapeutic response to radiotherapy.View full abstractDownload PDF (667K) -
Yukio FUJITA, Naoki TOHYAMA, Atsushi MYOJOYAMA, Hidetoshi SAITOH2010 Volume 51 Issue 6 Pages 707-713
Published: 2010
Released on J-STAGE: November 23, 2010
Advance online publication: October 20, 2010JOURNAL FREE ACCESSTo reduce the uncertainty of absorbed dose for high energy photon beams, water has been chosen as a reference material by the dosimetry protocols. However, solid phantoms are used as media for absolute dose verification of intensity modulated radiotherapy (IMRT). For the absorbed dose measurement, the fluence scaling factor is used for converting an ionization chamber reading in a solid phantom to absorbed dose to water. Furthermore the depth scaling factor is indispensable in determining the fluence scaling factor. For IMRT beams, a photon energy spectrum is varied by transmitting through a multileaf collimator and attenuating in media. However, the effects of spectral variations on depth scaling have not been clarified yet. In this study, variations of photon energy spectra were determined using the EGS Monte Carlo simulation. The depth scaling factors for commercially available solid phantoms were determined from effective mass attenuation coefficients using photon energy spectra. The results clarified the effect of spectral variation on the depth scaling and produced an accurate scaling method for IMRT beams.View full abstractDownload PDF (896K) -
Takahiro OIKE, Tatsuya OHNO, Masaru WAKATSUKI, Shin-ei NODA, Jun-ichi ...2010 Volume 51 Issue 6 Pages 715-721
Published: 2010
Released on J-STAGE: November 23, 2010
Advance online publication: October 20, 2010JOURNAL FREE ACCESSThe purpose of this study was to compare dose reduction to the small bowel and sacral bone by two-field and four-field techniques when the common iliac lymph node region is excluded from the radiation field in external beam radiotherapy of uterine cervical cancer. Thirteen patients with cervical cancer were entered into the study. Conventional treatment plans based on bony landmarks were made with parallel-opposed two-field technique (C2F) and four-field box technique (C4F). Modified C2F (M2F) and C4F (M4F) plans of excluding the common iliac lymph node region from the conventional radiation fields were created in reference to the bifurcations of pelvic arteries in computed tomography images. For each patient, the dose volume histograms for the small bowel and sacral bone resulting from the C2F, C4F, M2F, and M4F plans were compared. The volumes were obtained at 10 levels of prescribed dose, at increments of 10%, from 5 Gy to 50 Gy. By sparing both small bowel and sacral bone, the M2F and M4F plans were significantly better than the C2F and C4F plans at any dose level (p < 0.05), respectively. In addition, the M4F plan was significantly better than the M2F plan in sparing both small bowel at 10–50% of the prescribed dose (p < 0.05) and sacral bone at 40–100% of the prescribed dose (p < 0.05). The present study suggests that modified treatment planning could be useful for selected patients for reducing small bowel complications and insufficiency fracture after radiotherapy.View full abstractDownload PDF (546K) -
Rie TANAKA, Katsuhiro ICHIKAWA, Shinichiro MORI, Suguru DOBASHI, Motok ...2010 Volume 51 Issue 6 Pages 723-731
Published: 2010
Released on J-STAGE: November 23, 2010
Advance online publication: October 23, 2010JOURNAL FREE ACCESSReal-time tumor tracking in external radiotherapy can be achieved by diagnostic (kV) X-ray imaging with a dynamic flat-panel detector (FPD). The purpose of this study was to address image lag in target tracking and its influence on the accuracy of tumor tracking. Fluoroscopic images were obtained using a direct type of dynamic FPD. Image lag properties were measured without test devices according to IEC 62220-1. Modulation transfer function (MTF) and profile curves were measured on the edges of a moving tungsten plate at movement rate of 10 and 20 mm/s, covering lung tumor movement of normal breathing. A lung tumor and metal sphere with blurred edge due to image lag was simulated using the results and then superimposed on breathing chest radiographs of a patient. The moving target with and without image lag was traced using a template-matching technique. In the results, the image lag for the first frame after X-ray cutoff was 2.0% and decreased to less than 0.1% in the fifth frame. In the measurement of profile curves on the edges of static and moving tungsten material plates, the effect of image lag was seen as blurred edges of the plate. The blurred edges of a moving target were indicated as reduction of MTF. However, the target could be traced within an error of ± 5 mm. The results indicated that there was no effect of image lag on target tracking in usual breathing speed in a radiotherapy situation.View full abstractDownload PDF (589K) -
Genro KASHINO, Yong LIU, Minoru SUZUKI, Shin-ichiro MASUNAGA, Yuko KIN ...2010 Volume 51 Issue 6 Pages 733-740
Published: 2010
Released on J-STAGE: November 23, 2010
JOURNAL FREE ACCESSThe radioprotective effects of dimethyl sulfoxide (DMSO) have been known for many years, and the suppression of hydroxyl (OH) radicals induced by ionizing radiation has been thought to be the main cause of this effect. However, the DMSO concentration used was very high, and might be toxic, in earlier studies. In the present study, we administered a lower, non-toxic concentration (0.5%, i.e., 64 mM) of DMSO before irradiation and examined its radioprotective effects. Colony formation assay and micronucleus assay showed significant radioprotective effects in CHO, but not in xrs5, which is defective in the repair function of DNA double-strand breaks. The levels of phosphorylated H2AX and the formation of 53BP1 foci 15 minutes after irradiation, which might reflect initial DNA double-strand breaks, in DMSO-treated CHO cells were similar to those in non-treated cells, suggesting that the radioprotective effects were not attributable to the suppression of general indirect action in the lower concentration of DMSO. On the other hand, 2 hours after irradiation, the average number of 53BP1 foci, which might reflect residual DNA double-strand breaks, was significantly decreased in DMSO-treated CHO cells compared to non-treated cells. The results indicated that low concentration of DMSO exerts radioprotective effects through the facilitation of DNA double-strand break repair rather than through the suppression of indirect action.View full abstractDownload PDF (877K) -
Liren QIAN, Fei CAO, Jianguo CUI, Yicun WANG, Yuecheng HUANG, Yunhai C ...2010 Volume 51 Issue 6 Pages 741-747
Published: 2010
Released on J-STAGE: November 23, 2010
JOURNAL FREE ACCESSMost ionizing radiation-induced damage is caused by hydroxyl radicals, and the selective reduction of hydroxyl by hydrogen in vitro has been demonstrated previously. Irradiation of the heart can cause chronic cardiac disease. This study was designed to test the hypothesis that hydrogen-rich water (pure water saturated with molecular hydrogen), which is easy to use, induces cardioprotection against ionizing irradiation injury in mice. In this paper, we demonstrate that hydrogen can protect myocardium degeneration from radiation-induced injury, decrease myocardium malondialdehyde (MDA), 8-hydroxydeoxyguanosine (8-OHdG) levels, and increase myocardium endogenous antioxidants in vivo. We suggest that hydrogen has a cardioprotective effect against radiation induced injury.View full abstractDownload PDF (695K) -
Takuya KAMINUMA, Katsuyuki KARASAWA, Nahoko HANYU, Ta-Chen CHANG, Genc ...2010 Volume 51 Issue 6 Pages 749-753
Published: 2010
Released on J-STAGE: November 23, 2010
Advance online publication: October 23, 2010JOURNAL FREE ACCESSRecently, the number of human immunodeficiency virus (HIV) -positive patients has increased in Japan. HIV-positive patients are at a higher risk of cancer than the general population. This paper retrospectively reports the acute adverse effects of radiation therapy on HIV-positive patients who were treated at Tokyo Metropolitan Cancer and Infectious diseases Center Komagome Hospital (TMCICK). Thirty-one cases involving 24 HIV-positive cancer patients who were treated at TMCICK from January 1997 to March 2009 were included in this study. All acute adverse effects of radiation therapy were examined during, and one month after, the last radiation therapy session. Acute adverse effects were classified according to the site of radiation therapy treatment and analyzed using the Common Terminology Criteria for Adverse Events (CTCAE) version 3.0. Grade 3 acute adverse effects were seen in 17% of cases, and Grade 2 toxicities were found in 23% of patients. Damage to the skin and mucosa, including stomatitis or diarrhea, tended to occur after low-dose radiation therapy; however, no severe acute adverse effects were seen in other organs, such as the brain, lung, and bone. Acute adverse effects tended to occur earlier in HIV-positive patients and became severe more frequently than in the general population. In particular, disorders of the mucosa, such as those of the oral cavity, pharynx, and intestine, tended to occur rapidly. It was shown that radiation therapy is safe when treatment is performed carefully and that it is a very useful treatment for cancer in HIV-positive patients.View full abstractDownload PDF (631K) -
Atsuko OMORI, Takako CHIBA, Ikuo KASHIWAKURA2010 Volume 51 Issue 6 Pages 755-763
Published: 2010
Released on J-STAGE: November 23, 2010
Advance online publication: November 10, 2010JOURNAL FREE ACCESSHematopoietic stem/progenitor cells (HSPCs) in placental/umbilical cord blood (CB), which is neonatal peripheral blood, have increasingly been used for hematopoietic stem cell transplantations. It is likely HSPCs are sensitive to extracellular oxidative stresses, such as ionizing radiation and redox-directed chemotherapeutic agents. However, the radiosensitivity of HSPCs and neonatal hematopoietic system remains unclear. This study investigated the potential relationship between the radiosensitivity of HSPCs in CB, which was obtained from singleton and full-term deliveries, and maternal/neonatal obstetric factors. Freshly prepared CB CD34+ cells exposed to 2 Gy X-irradiation were assayed for hematopoietic progenitor cells such as colony-forming unit-granulocyte-macrophage (CFU-GM), burst-forming unit-erythroid (BFU-E), colony-forming unit-granulocyte-erythroid-macrophage-megakaryocyte (CFU-Mix), and colony-forming unit-megakaryocyte (CFU-Meg). As a result, the neonatal weight, placental weight, CB volume, total low-density (LD) cells, and CD34+ cells showed mutually significant positive correlations. The CB volume and total LD cells showed a significant reverse correlation with the surviving fraction of CFU-Meg. The surviving fraction of CFU-GM in spring (March–May) was significantly higher than that in autumn (September–November). The surviving fraction of CFU-Meg in the spring was significantly lower than that in the autumn. Male neonates showed a significantly higher surviving fraction of CFU-GM than female neonates. Contrarily, females showed a significantly higher surviving fraction of CFU-Meg than males. The present results suggest that the obstetric factors, such as the season of birth and neonatal gender, influence the radiosensitivity of neonatal hematopoiesis.View full abstractDownload PDF (736K)
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2010 Volume 51 Issue 6 Pages Cover06_1-Cover06_8
Published: 2010
Released on J-STAGE: November 23, 2010
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