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Sample records for abnormalities radiation-induced

  1. Gamma radiation induced micronuclei and erythrocyte cellular abnormalities in the fish Catla catla

    Anbumani, S. [Biodosimetry Laboratory, Radiological Safety Division, Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam, Tamilnadu 603102 (India); Mohankumar, Mary N., E-mail: marynmk@rediffmail.com [Biodosimetry Laboratory, Radiological Safety Division, Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam, Tamilnadu 603102 (India)

    2012-10-15

    Ionizing radiation induced DNA damage in fishes is a scarcely studied topic and very few studies are available in fishes exposed to ionizing radiation using the erythrocyte micronucleus assay under laboratory conditions. Since radionuclides released accidentally or during a nuclear disaster can contaminate inland water bodies, biomonitoring methods are required for assessing the impacts of high and low levels of radiation that may ultimately result in ionizing radiation exposure to both humans and non-human biota. Fresh water fish, Catla catla were subjected to protracted (0.002 Gy/min) and acute (3.2 Gy/min) gamma radiation to a total dose of 5 Gy. Peripheral blood samples were collected at different intervals (days 3, 6, 12, 18, 30, 45, 90, 135, 202) and analyzed by the erythrocyte micronucleus assay. Nuclear anomalies observed were micronuclei (MN), deformed nuclei (DN), nuclear bud (NBu), nuclear bridge (NBr), vacuolated nucleus (VN), binucleated cell (BNC), apoptotic cells (AC) while cytoplasmic abnormalities detected were vacuolated cytoplasm (VC), anisochromasia (AN), echinocytes (EC) and enucleus (EN). Both exposures caused a statistically significant increase in nuclear and cytoplasmic abnormalities that correlated with micronucleus and other nuclear anomalies. However, the extent of damage is higher after an acute exposure lasting for a longer period leading to apoptosis. Nuclear and cytoplasmic abnormalities are the resultants of gamma radiation induced genotoxicity and cytotoxicity.

  2. Proliferation, differentiation, and possible radiation-induced chromosome abnormalities in circulating hemopoietic stem cells

    The effects of atomic bomb radiation on hemopoietic stem cells were studied cytogenetically and from the aspect of differentiation and proliferation, using single colonies derived from human hemopoietic stem cells. The subjects studied were A-bomb survivors in the high dose exposure group (T65D 100 + rad) with a high incidence (10 % or more) of radiation-induced chromosome abnormalities in their peripheral lymphocytes, and their controls. Examinations were performed on 21 A-bomb survivors (10 males and 11 females) and 11 controls (5 males and 6 females). Colony formation of hemopoietic stem cells (granulocyte/monocyte-colony-forming cells, GM-CFC and burst-forming unit-erythrocytes, BFU-E) was made by the methylcellulose method patterned after the methods of Iscove et al and Ogawa et al using 5 - 10 ml of peripheral blood. Chromosome specimens were prepared from single colonies by the micromethod which we have reported elsewhere. The total number of colonies analyzed in the exposed group was 131 GM-CFC and 75 BFU-E. Chromosome abnormalities were observed in 15 (11.5 %) and 9 (12.0 %) colonies, respectively. In the control group, the total number of colonies analyzed was 61 GM-CFC and 41 BFU-E, but none of the colonies showed chromosome abnormalities. A highly significant difference in chromosome abnormalities was demonstrated by an exact test with a probability of 0.3 % for GM-CFC and 1.7 % for BFU-E. The karyotypes of chromosome abnormalities obtained from the colonies of hemopoietic stem cells in the exposed group were mostly translocations, but deletion and marker chromosomes were also observed. In two individuals, such karyotypic abnormalities as observed in the peripheral lymphocytes were seen also in the hemopoietic precursor cells. This finding suggests that radiation may produce an effect even on relatively undifferentiated hemopoietic stem cells. (author)

  3. Radiation-induced myocardial perfusion abnormalities in breast cancer patients following external beam radiation therapy

    Mohammad Eftekhari

    2015-01-01

    Full Text Available Objective(s: Radiation therapy for breast cancer can induce myocardial capillary injury and increase cardiovascular morbidity and mortality. A prospective cohort was conducted to study the prevalence of myocardial perfusion abnormalities following radiation therapy of left-sided breast cancer patients as compared to those with right–sided cancer. Methods: To minimize potential confounding factors, only those patients with low 10-year risk of coronary artery disease (based on Framingham risk scoring were included. All patients were initially treated by modified radical mastectomy and then were managed by postoperative 3D Conformal Radiation Therapy (CRT to the surgical bed with an additional 1-cm margin, delivered by 46-50 Gy (in 2 Gy daily fractions over a 5-week course. The same dose-adjusted chemotherapy regimen (including anthracyclines, cyclophosphamide and taxol was given to all patients. Six months after radiation therapy, all patients underwent cardiac SPECT for the evaluation of myocardial perfusion. Results: A total of 71 patients with a mean age of 45.3±7.2 years [35 patients with leftsided breast cancer (exposed and 36 patients with right-sided cancer (controls] were enrolled. Dose-volume histogram (DVH [showing the percentage of the heart exposed to >50% of radiation] was significantly higher in patients with left-sided breast cancer. Visual interpretation detected perfusion abnormalities in 42.9% of cases and 16.7% of controls (P=0.02, Odds ratio=1.46. In semiquantitative segmental analysis, only apical (28.6% versus 8.3%, P=0.03 and anterolateral (17.1% versus 2.8%, P=0.049 walls showed significantly reduced myocardial perfusion in the exposed group. Summed Stress Score (SSS of>3 was observed in twelve cases (34.3%, while in five of the controls (13.9%,(Odds ratio=1.3. There was no significant difference between the groups regarding left ventricular ejection fraction. Conclusion: The risk of radiation induced myocardial

  4. Abnormal phenotype of human cultured fibroblasts from superficial radiation-induced fibrosis (RIF)

    Pathophysiological aspects of human RIF have not been well characterized and our present knowledge is mostly established on extrapolated data from experimental in vivo studies or in vitro cell irradiation. We developed human cell cultures from superficial RIF samples, in order to analyze directly the long term process following therapeutic irradiation. Our study showed that in human RIF, characterized by an heterogeneous extra-cellular matrix deposition, atrophic vascularization, myo-fibroblast like cells and inflammatory cells, the surviving cells in culture exhibited a dramatic reduced proliferation and a low metabolism, characteristic signs of a senescence process. These results might explain the delayed radiation-induced necrosis as an ultimate evolution of RIF. (authors)

  5. Cress oil modulates radiation-induced hormonal, histological, genetic disorders and sperm head abnormalities in albino rat

    Watercress (Nasturtium officinale) is an aquatic perennial herb of mustard family. The plant is rich in glucosinolates, specially gluconasturtin, which can be hydrolyzed to 2- phenylethyl isothiocyanate (PEITC) and known to activate detoxification enzymes. Cress oil (0.1 ml/kg/day) was given to rats, receiving a standard diet, by gavage for 2 weeks before whole body gamma irradiation at 7 Gy (single dose) and treatment was continued one week after irradiation. The results obtained showed that cress oil treatment significantly diminished the radiation-induced alterations in levels of testosterone, luteinizing hormone (LH), follicle stimulating hormone (FSH) and prolactin in serum and also blunted the increased levels of thiobarbituric acid reactive substances (TBARS) in serum and testes. Histopathological examination of testicular tissue showed that radiation exposure leads to atrophic testis with marked loss of germ cells, remaining tall pink Sertoli cells, peri tubular fibrosis and interstitial fibrosis. Cress oil treatments ameliorated the intensity of these changes where signs of partial recovery were observed in the histological configuration of leydig cells, seminiferous tubules, spermatocytes and in the structure of interstitial cells. Moreover, administration of cress oil significantly reduced the score of sperm head abnormalities and chromosomal aberration frequencies. It could be concluded that watercress may have a bio protective effect on radiation-induced oxidative stress where phytochemicals present in watercress could protect against hormone-dependent disease

  6. Reduction of transgenerational radiation induced genetic damages observed as numerical chromosomal abnormalities in preimplantation embryos by vitamin E

    To study the effects of parental gamma irradiation (4 Gy) of NMRI (Naval Medical Research Institute) mice on the numerical chromosome abnormalities in subsequent preimplantation embryos in the presence of vitamin E (200 IU/kg), super-ovulated irradiated females were mated with irradiated males at weekly intervals in successive 6 weekly periods. About 68 h post coitus, 8-cell embryos were fixed on slides using standard methods in order to screen for abnormalities in chromosome number. In embryos generated by irradiated mice, the frequency of aneuploids dramatically increased compared to control unirradiated groups (p < 0.001), while no significant difference were observed within irradiated groups mated at weekly interval. Administration of vitamin E significantly decreased chromosomal aberrations in all groups (p < 0.05). Data indicate that gamma irradiation affects spermatogenesis and oogenesis and causes DNA alterations that may lead to chromosome abnormalities in subsequent embryos. Vitamin E effectively reduced the frequency of abnormalities. The way vitamin E reduces genotoxic effects of radiation might be via radical scavenging or antioxidative mechanism. (authors)

  7. Radiation-induced chromosomal instability

    Ritter, S. [GSI, Biophysics, Darmstadt (Germany)

    1999-03-01

    Recent studies on radiation-induced chromosomal instability in the progeny of exposed mammalian cells were briefly described as well as other related studies. For the analysis of chromosomal damage in clones, cells were seeded directly after exposure in cell well-dish to form single cell clones and post-irradiation chromosome aberrations were scored. Both exposure to isoeffective doses of X-ray or 270 MeV/u C-ions (13 keV/{mu}m) increased the number of clones with abnormal karyotype and the increase was similar for X-ray and for C-ions. Meanwhile, in the progeny of cells for mass cultures, there was no indication of a delayed expression of chromosomal damage up to 40 population doublings after the exposure. A high number of aberrant cells were only observed directly after exposure to 10.7 MeV/u O-ions, i.e. in the first cycle cells and decreased with subsequent cell divisions. The reason for these differences in the radiation-induced chromosomal instability between clonal isolates and mass culture has not been clarified. Recent studies indicated that genomic instability occurs at a high frequency in the progeny of cells irradiated with both sparsely and densely ionizing radiation. Such genomic instability is thought likely to increase the risk of carcinogenesis, but more data are required for a well understanding of the health risks resulting from radiation-induced delayed instability. (M.N.)

  8. Radiation-induced pneumothorax

    Epstein, D.M.; Littman, P.; Gefter, W.B.; Miller, W.T.; Raney, R.B. Jr.

    1983-01-01

    Pneumothorax is an uncommon complication of radiation therapy to the chest. The proposed pathogenesis is radiation-induced fibrosis promoting subpleural bleb formation that ruptures resulting in pneumothorax. We report on two young patients with primary sarcomas without pulmonary metastases who developed spontaneous pneumothorax after irradiation. Neither patient had antecedent radiographic evidence of pulmonary fibrosis.

  9. Radiation-induced pneumothorax

    Pneumothorax is an uncommon complication of radiation therapy to the chest. The proposed pathogenesis is radiation-induced fibrosis promoting subpleural bleb formation that ruptures resulting in pneumothorax. We report on two young patients with primary sarcomas without pulmonary metastases who developed spontaneous pneumothorax after irradiation. Neither patient had antecedent radiographic evidence of pulmonary fibrosis

  10. Radiation Induced Fermion Resonance

    Esposito, S.; M. W. Evans; Recami, E.

    1998-01-01

    The Dirac equation is solved for two novel terms which describe the interaction energy between the half integral spin of a fermion and the classical, circularly polarized, electromagnetic field. A simple experiment is suggested to test the new terms and the existence of radiation induced fermion resonance.

  11. Radiation induced oral mucositis

    P S Satheesh Kumar; Anita Balan; Arun Sankar; Tinky Bose

    2009-01-01

    Patients receiving radiotherapy or chemotherapy will receive some degree of oral mucositis The incidence of oral mucositis was especially high in patients: (i) With primary tumors in the oral cavity, oropharynx, or nasopharynx; (ii) who also received concomitant chemotherapy; (iii) who received a total dose over 5,000 cGy; and (iv) who were treated with altered fractionation radiation schedules. Radiation-induced oral mucositis affects the quality of life of the patients and the family concer...

  12. Radiation induced pesticidal microbes

    Kim, Ki Yup; Lee, Y. K.; Kim, J. S.; Kim, J. K.; Lee, S. J.; Lim, D. S

    2001-01-01

    To isolate pesticidal microbes against plant pathogenic fungi, 4 strains of bacteria(K1. K3, K4, YS1) were isolated from mushroom compost and hot spring. K4, K1, K3, YS1 strain showed wide antifungal spectrum and high antifungal activities against 12 kinds of fungi. Specific proteins and the specific transcribed genes were found from the YS1 and its radiation-induced mutants. And knock-out mutants of antifungal activity were derived by transposon mutagenesis. From these knock-out mutants, the antifungal activity related genes and its modification by gamma-ray radiation are going to be studied. These results suggested that radiation could be an useful tool for the induction of functional mutants.

  13. Radiation induced pesticidal microbes

    To isolate pesticidal microbes against plant pathogenic fungi, 4 strains of bacteria(K1. K3, K4, YS1) were isolated from mushroom compost and hot spring. K4, K1, K3, YS1 strain showed wide antifungal spectrum and high antifungal activities against 12 kinds of fungi. Specific proteins and the specific transcribed genes were found from the YS1 and its radiation-induced mutants. And knock-out mutants of antifungal activity were derived by transposon mutagenesis. From these knock-out mutants, the antifungal activity related genes and its modification by gamma-ray radiation are going to be studied. These results suggested that radiation could be an useful tool for the induction of functional mutants

  14. Radiation induced oral mucositis

    P S Satheesh Kumar

    2009-01-01

    Full Text Available Patients receiving radiotherapy or chemotherapy will receive some degree of oral mucositis The incidence of oral mucositis was especially high in patients: (i With primary tumors in the oral cavity, oropharynx, or nasopharynx; (ii who also received concomitant chemotherapy; (iii who received a total dose over 5,000 cGy; and (iv who were treated with altered fractionation radiation schedules. Radiation-induced oral mucositis affects the quality of life of the patients and the family concerned. The present day management of oral mucositis is mostly palliative and or supportive care. The newer guidelines are suggesting Palifermin, which is the first active mucositis drug as well as Amifostine, for radiation protection and cryotherapy. The current management should focus more on palliative measures, such as pain management, nutritional support, and maintenance, of good oral hygiene

  15. [Radiation-induced cancers].

    Dutrillaux, B

    1998-01-01

    The induction of malignant diseases is one of the most concerning late effects of ionising radiation. A large amount of information has been collected form atomic bomb survivors, patients after therapeutic irradiation, occupational follow-up and accidentally exposed populations. Major uncertainties persist in the (very) low dose range i.e., population and workers radioprotection. A review of the biological mechanisms leading to cancer strongly suggests that the vast majority of radiation-induced malignancies arise as a consequence of recessive mutations of tumour-suppressor genes. These mutations can be unveiled by ageing, this process being possibly furthered by constitutional or acquired genomic instability. The individual risk is likely to be very low, probably because of the usual dose level. However, the magnitude of medical exposure and the reliance of our societies on nuclear industry are so high that irreproachable decision-making processes and standards for practice are inescapable. PMID:9868399

  16. Two pediatric cases of high dose radiation-induced meningiomas

    Nagai, Miho [National Yokosuka Hospital, Kanagawa (Japan); Nagashima, Goro; Fujimoto, Tsukasa; Aoyagi, Masaru; Takasato, Yoshio

    2001-10-01

    There have been many reports of low dose radiation-induced meningiomas, and the number of reports of high dose radiation-induced meningiomas has been increasing recently. In this report, we present two cases of pediatric radiation-induced meningiomas, one 14 years after 36 Gy of radiation therapy for medulloblastoma and the other 8 years after 20 Gy of local radiation therapy for germinoma. Both patients underwent surgical removal of the meningiomas. The case of medulloblastoma was later revealed to be basal cell phacomatosis syndrome. Basal cell phacomatosis syndrome is a disease that occurs as a result of abnormality of chromosome 9. We speculate that the occurrence of radiation-induced meningioma may have been related to the basic genetic vulnerability of the patients. (author)

  17. RIS - radiation induced superheroes

    We all know & love our Superheroes. Whether we realised it or not when we were kids growing up watching or reading 'Faster than a locomotive...' or ...'he does whatever a spider can...' , the fantasy of these cool hero characters was created, in one way or another, by the influence of RADIATION. Our Radiation Induced Superheroes include such greats as Superman, Spiderman & the Incredible Hulk. There were other lesser known ones which didn't make the cut with this 'bit of fun' poster. Others include names like The Fantastic Four: Mr Fantastic, The Invisible Woman, The Human Torch & Thing - all exposed to high-level cosmic radiation during an outer space scientific mission. Superpowers such as the element of 'Radiation Control' are available to characters like Metallo - a Superman adversary & Ultron - a baddie in the Avengers comics. We all know that the physics makes these characters complete works of fiction, but it's fun to watch their TV shows (Superman is STILL on TV in 'Smallville'), movies go without saying - dozens of them around & still being created & some of us even still read the comics!

  18. Radiation induced nano structures

    Full text: Nanometer-size silicon clusters have been attracting much attention due to their technological importance, in particular, as promising building blocks for nano electronic and nano photonic systems. Particularly, silicon wires are of great of interest since they have potential for use in one-dimensional quantum wire high-speed field effect transistors and light-emitting devices with extremely low power consumption. Carbon and metal nano structures are studied very intensely due to wide possible applications. Radiation material sciences have been dealing with sub-micron objects for a long time. Under interaction of high energy particles and ionizing radiation with solids by elastic and inelastic mechanisms, at first point defects are created, then they form clusters, column defects, disordered regions (amorphous colloids) and finally precipitates of another crystal phase in the matrix. Such irradiation induced evolution of structure defects and phase transformations was observed by X-diffraction techniques in dielectric crystals of quartz and corundum, which exist in and crystal modifications. If there is no polymorphism, like in alkali halide crystals, then due to radiolysis halogen atoms are evaporated from the surface that results in non-stoichiometry or accumulated in the pores formed by metal vacancies in the sub-surface layer. Nano-pores are created by intensive high energy particles irradiation at first chaotically and then they are ordered and in part filled by inert gas. It is well-known mechanism of radiation induced swelling and embrittlement of metals and alloys, which is undesirable for construction materials for nuclear reactors. Possible solution of this problem may come from nano-structured materials, where there is neither swelling nor embrittlement at gas absorption due to very low density of the structure, while strength keeps high. This review considers experimental observations of radiation induced nano-inclusions in insulating

  19. Ionizing radiation induced cataract

    Until recently it was believed that the cataract (opacity of the eye lens) is a deterministic effect with a dose threshold of several Gray in dependence on the exposure conditions. Studies in Hiroshima and Nagasaki, in the vicinity of Chernobyl, of American radiologic technologists, astronauts, and patients after having received several computer tomographies of the head region, however, have shown that this assumption is not correct. It had been overlooked in the past that with decreasing dose the latency period is increasing. Therefore, the originally available studies were terminated too early. The more recent studies show that, in the case of a threshold existing at all, it is definitely below 0.8 Gy independently of an acute or a chronic exposure. All studies, however, include 0 Gy in the confidence interval, so that the absence of a dose threshold cannot be excluded. The German Commission on Radiological Protection (Strahlenschutzkommission, SSK) suggested therefore among others: targeted recording of the lens dose during activities which are known to be associated with possible significant lens exposure, examination of the lens should be included as appropriate in the medical monitoring of people occupationally exposed to radiation, if there is potentially high lens exposure, adoption of research strategies to develop a basic understanding of the mechanisms underlying radiation induced cataracts. The International Commission on Radiological Protection (ICRP) actually assumes a threshold dose of 0.5 Gy and, based on this assumption, has recommended in 2011 to reduce the dose limit for the eye lens from 150 mSv in a year to 20 mSv in a year for people occupationally exposed to ionising radiation. (orig.)

  20. Radiation induced diarrhoea - literature review

    Radiation-induced diarrhoea is an acute side effect of radiotherapy treatment to the pelvic area, experienced by nearly all patients. This paper will explore the patho-physiological rationale of diarrhoea, the causes of radiation-induced diarrhoea, the factors that influence the severity and occurrence, and the treatment of diarrhoea in relation to the radiotherapy setting, by analysing the current literature and will conclude by outlining future directions in this field. Copyright (2004) Australian Institute of Radiography

  1. Radiation-induced scoliosis

    Observation was made as to 9 cases who received x-ray therapy (1,500 - 3,500 R) over the abdomen at their childhood and description was also made as to scoliosis. Mild scoliosis was recognized in 6 cases, which was probably due to their age under ten years old. The future observation was necessary in cases who passed through the period of adolescent growth spurt. There was a case who showed wedge shape deformation of the spine at 1,500 R. Abnormal case was not recognized in lordosis. (Serizawa, K.)

  2. Radiation-induced intestinal inflammation

    Meritxell Mollà; Julián Panés

    2007-01-01

    Radiation induces an important inflammatory response in the irradiated organs, characterized by leukocyte infiltration and vascular changes that are the main limiting factor in the application of this therapeutic modality for the treatment of cancer. Recently, a considerable investigative effort has been directed at determining the molecular mechanisms by which radiation induces leukocyte recruitment, in order to create strategies to prevent intestinal inflammatory damage. In these review, we consider current available evidence on the factors governing the process of leukocyte recruitment in irradiated organs, mainly derived from experimental studies, with special attention to adhesion molecules, and their value as therapeutic targets.

  3. Radiation-induced cardiovascular effects

    Tapio, Soile

    Recent epidemiological studies indicate that exposure to ionising radiation enhances the risk of cardiovascular mortality and morbidity in a moderate but significant manner. Our goal is to identify molecular mechanisms involved in the pathogenesis of radiation-induced cardiovascular disease using cellular and mouse models. Two radiation targets are studied in detail: the vascular endothelium that plays a pivotal role in the regulation of cardiac function, and the myocardium, in particular damage to the cardiac mitochondria. Ionising radiation causes immediate and persistent alterations in several biological pathways in the endothelium in a dose- and dose-rate dependent manner. High acute and cumulative doses result in rapid, non-transient remodelling of the endothelial cytoskeleton, as well as increased lipid peroxidation and protein oxidation of the heart tissue, independent of whether exposure is local or total body. Proteomic and functional changes are observed in lipid metabolism, glycolysis, mitochondrial function (respiration, ROS production etc.), oxidative stress, cellular adhesion, and cellular structure. The transcriptional regulators Akt and PPAR alpha seem to play a central role in the radiation-response of the endothelium and myocardium, respectively. We have recently started co-operation with GSI in Darmstadt to study the effect of heavy ions on the endothelium. Our research will facilitate the identification of biomarkers associated with adverse cardiac effects of ionising radiation and may lead to the development of countermeasures against radiation-induced cardiac damage.

  4. Radiation-induced leiomyosarcoma of the oropharynx

    Maier Wolfgang

    2006-08-01

    Full Text Available Abstract Leiomyosarcoma is a malignant mesenchymal tumor originating from smooth muscle cells, which most frequently develops in the myometrium and in the gastro-intestinal tract. Reviewing the international literature, radiation-induced sarcoma arise in 0.035 to 0.2 % of all irradiated patients. Especially in the head and neck region, radiation-induced leiomyosarcoma is an extremely rare lesion. The authors report a case of a radiation-induced leiomyosarcoma of the tonsillar region of the oropharynx in a 51-year-old male patient, who had undergone radiation therapy of this region 38 years before. The lesion was treated by radical surgery. Diagnostic steps, histological presentation and therapy are described in detail and the literature concerning radiation induced malignancies in general as well as radiation induced leiomyosarcoma in particular is reviewed. The highlights of this case are an extremely uncommon location and a rare pathological entity of radiation induced malignancies.

  5. Radiation-induced pseudotumor following therapy for soft tissue sarcoma

    The purpose of this study was to describe the prevalence and imaging appearance of radiation induced pseudotumors in patients following radiation therapy for extremity soft tissue sarcomas. We retrospectively reviewed the serial magnetic resonance (MR) images of 24 patients following radiation therapy for extremity soft tissue sarcomas. A total of 208 exams were reviewed (mean, 8.7 exams per patient) and included all available studies following the start of radiation therapy. Exams were analyzed for the identification of focal signal abnormalities within the surgical bed suggesting local tumor recurrence. Histopathologic correlation was available in nine patients suspected of having local tumor recurrence. Additional information recorded included patient demographics, tumor type and location, radiation type, and dose. The study group consisted of 12 men and 12 women, having an average age of 63 years (range, 39-88 years). Primary tumors were malignant fibrous histiocytoma (n = 13), leiomyosarcoma (n = 6), liposarcoma (n = 3), synovial sarcoma (n = 1), and extraskeletal chondrosarcoma (n = 1). All lesions were high-grade sarcomas, except for two myxoid liposarcomas. Average patient radiation dose was 5,658 cGy (range, 4,500-8,040 cGy). Average follow-up time was 63 months (range, 3-204 months). Focal signal abnormalities suggesting local recurrence were seen in nine (38%) patients. Three of the nine patients with these signal abnormalities were surgically proven to have radiation-induced pseudotumor. The pseudotumors developed between 11 and 61 months following the initiation of radiation therapy (mean, 38 months), with an average radiation dose of 5,527 cGy (range, 5,040-6,500 cGy). MR imaging demonstrated a relatively ill-defined ovoid focus of abnormal signal and intense heterogeneous enhancement with little or no associated mass effect. MR imaging of radiation-induced pseudotumor typically demonstrates a relatively ill-defined ovoid mass-like focus of intense

  6. Radiation-induced pseudotumor following therapy for soft tissue sarcoma

    Moore, Lacey F.; Kransdorf, Mark J. [Mayo Clinic, Department of Radiology, Jacksonville, FL (United States); Buskirk, Steven J. [Mayo Clinic, Department of Radiation Oncology, Jacksonville, FL (United States); O' Connor, Mary I. [Mayo Clinic, Department of Orthopedic Surgery, Jacksonville, FL (United States); Menke, David M. [Mayo Clinic, Department of Pathology, Jacksonville, FL (United States)

    2009-06-15

    The purpose of this study was to describe the prevalence and imaging appearance of radiation induced pseudotumors in patients following radiation therapy for extremity soft tissue sarcomas. We retrospectively reviewed the serial magnetic resonance (MR) images of 24 patients following radiation therapy for extremity soft tissue sarcomas. A total of 208 exams were reviewed (mean, 8.7 exams per patient) and included all available studies following the start of radiation therapy. Exams were analyzed for the identification of focal signal abnormalities within the surgical bed suggesting local tumor recurrence. Histopathologic correlation was available in nine patients suspected of having local tumor recurrence. Additional information recorded included patient demographics, tumor type and location, radiation type, and dose. The study group consisted of 12 men and 12 women, having an average age of 63 years (range, 39-88 years). Primary tumors were malignant fibrous histiocytoma (n = 13), leiomyosarcoma (n = 6), liposarcoma (n = 3), synovial sarcoma (n = 1), and extraskeletal chondrosarcoma (n = 1). All lesions were high-grade sarcomas, except for two myxoid liposarcomas. Average patient radiation dose was 5,658 cGy (range, 4,500-8,040 cGy). Average follow-up time was 63 months (range, 3-204 months). Focal signal abnormalities suggesting local recurrence were seen in nine (38%) patients. Three of the nine patients with these signal abnormalities were surgically proven to have radiation-induced pseudotumor. The pseudotumors developed between 11 and 61 months following the initiation of radiation therapy (mean, 38 months), with an average radiation dose of 5,527 cGy (range, 5,040-6,500 cGy). MR imaging demonstrated a relatively ill-defined ovoid focus of abnormal signal and intense heterogeneous enhancement with little or no associated mass effect. MR imaging of radiation-induced pseudotumor typically demonstrates a relatively ill-defined ovoid mass-like focus of intense

  7. Radiation-induced thermoacoustic imaging

    This invention provides a new technique for obtaining information non-invasively on the composition and structures of a material or body by detecting radiation-induced thermoacoustic image features. This is accomplished by utilizing the acoustic wave generated by sudden thermal stress. The sudden thermal stress is induced by a pulse of radiation which deposits energy causing a rapid, but very small, rise of temperature (typically, ΔT approximately 10sup(-6) - 10sup(-5) deg C). The radiation may be ionizing radiation, such as high energy electrons, photons (x-rays), neutrons, or other charged particles or it may be non-ionizing radiation, such as R.F. and microwave electromagnetic radiation and ultrasonic radiation. The choice of radiation depends on the nature of the body to be imaged and the type of information desired

  8. A study of radiation-induced cerebral vascular injury in nasopharyngeal carcinoma patients with radiation-induced temporal lobe necrosis.

    Jianhong Ye

    Full Text Available PURPOSE: To investigate radiation-induced carotid and cerebral vascular injury and its relationship with radiation-induced temporal lobe necrosis in nasopharyngeal carcinoma (NPC patients. METHODS AND MATERIALS: Fifty eight NPC patients with radiation-induced temporal lobe necrosis (TLN were recruited in the study. Duplex ultrasonography was used to scan bilateral carotid arterials to evaluate the intima-media thickness (IMT and occurrence of plaque formation. Flow velocities of bilateral middle cerebral arteries (MCAs, internal carotid arteries (ICAs and basal artery (BA were estimated through Transcranial Color Doppler (TCD. The results were compared with data from 33 patients who were free from radiation-induced temporal lobe necrosis after radiotherapy and 29 healthy individuals. RESULTS: Significant differences in IMT, occurrence of plaques of ICAs and flow velocities of both MCAs and ICAs were found between patients after radiotherapy and healthy individuals (p<0.05. IMT had positive correlation with post radiation interval (p = 0.049. Compared with results from patients without radiation-induced TLN, the mean IMT was significantly thicker in patients with TLN (p<0.001. Plaques were more common in patients with TLN than patients without TLN (p = 0.038. In addition, flow velocities of MCAs and ICAs in patients with TLN were much faster (p<0.001, p<0.001. Among patients with unilateral TLN, flow velocity of MCAs was significantly different between ipsilateral and contralateral sides to the lesion (p = 0.001. CONCLUSION: Thickening of IMT, occurrence of plaque formation and hemodynamic abnormality are more common in patients after radiotherapy, especially in those with TLN, compared with healthy individuals.

  9. Radiation induced carcinoma of the middle ear

    Radiation induced carcinoma of the middle ear is rare. Only four cases have been reported; an additional case is now described. The treatment approach for radiation induced carcinoma of the middle ear has not yet been established. Radiation therapy for advanced cases is discussed as an alternative to surgical treatment. Previous reported cases are reviewed

  10. Radiation-induced malignant and atypical peripheral nerve sheath tumors

    The reported peripheral nerve complications of therapeutic irradiation in humans include brachial and lumbar plexus fibrosis and cranial and peripheral nerve atrophy. We have encountered 9 patients with malignant (7) and atypical (2) peripheral nerve tumors occurring in an irradiated site suggesting that such tumors represent another delayed effect of radiation treatment on peripheral nerve. In all instances the radio-theray was within an acceptable radiation dosage, yet 3 patients developed local radiation-induced skin and bony abnormalities. The malignant peripheral nerve sheath tumors developed only in the radiation port. Animal studies support the clinical observation that malignant peripheral nerve sheath tumors can occur as a delayed effect of irradiation

  11. Cellular basis of radiation-induced fibrosis

    Fibrosis is a common sequela of both cancer treatment by radiotherapy and accidental irradiation and has been described in many tissues including skin, lung, heart and liver. The underlying mechanisms of the radiation-induced fibrosis still remain to be resolved. In the present review we tried to illustrate the basic cellular mechanisms of radiation-induced fibrosis based on the newest findings arising from molecular radiobiology and cell biology. Based on these findings the cellular mechanism of radiation-induced fibrosis can be seen as a multicellular process involving various interacting cell systems in the target organ resulting in the fibrotic phenotype of the fibroblast/fibrocyte cell system

  12. Radiation-induced changes in the breast

    Thirty-six postirradiation breast tissue specimens from 30 patients with breast cancer treated by primary radiation therapy were evaluated to define the effects of therapeutic doses of ionizing radiation on the residual non-neoplastic breast tissue. Breast tissue was sampled an average of 30.4 months after completion of therapy because of the development of new clinically or mammographically detectable abnormalities within the treated breasts. The average radiation dose was 6,399 rad to the primary tumor area and 4,778 rad to the remainder of the breast. Breast tissue sections from 35 nonirradiated patients served as control specimens. The most characteristic radiation effects consisted of atypical epithelial cells in the terminal duct lobular unit (TDLU) associated with lobular sclerosis and atrophy. These changes were present in all of the irradiated patients but varied in severity and extent among patients and within individual patients. This variation was not related to the presence or absence of carcinoma elsewhere in the specimen, radiation dose, patient age, time to postirradiation tissue sampling, or use of adjuvant chemotherapy. Epithelial atypia in larger ducts, stromal changes, and vascular changes were less frequent but were always accompanied by prominent TDLU changes. Radiation effects could usually be clearly distinguished from carcinoma involving the TDLU by the absence of both cellular proliferation and distention of the involved TDLU and by the preservation of cellular polarity and cohesion in areas of presumed radiation-induced injury. Familiarity with these changes is of considerable practical importance in that they must be distinguished from new or recurrent neoplasms

  13. Radiation-induced carcinoma of the penis

    Two patients with carcinoma of the penis were treated with interstitial radiation. They were cured of their disease for 17 and 21 years respectively and then developed radiation-induced tumours. (author)

  14. Immunohistochemical study of p53 overexpression in radiation-induced colon cancers

    The expressions of p53 and proliferating cell nuclear antigen (PCNA) were studied immunohistochemically from paraffin sections of 7 cases (9 lesions) of radiation-induced colon cancer and 42 cases of spontaneous colon cancer. Age distribution of radiation-induced and spontaneous colon cancer were 68.1 years (range, 56 to 77 years) and 67.4 years (range, 31 to 85 years), respectively. Among the radiation-induced colon cancers, there were 3 lesions of mucinous carcinoma (33%), a much higher than found for spontaneous mucinous cancer. Immunohistochemically, p53 protein expression was detected in 7/9 (78%) of radiation-induced cancers and in 23/42 (55%) of spontaneous colon cancers. χ2 analysis found no significant differences between radiation-induced and spontaneous colon cancers in age distribution or p53-positive staining for frequency, histopathology, or Dukes'' classification. In radiation colitis around the cancers including aberrant crypts, spotted p53 staining and abnormal and scattered PCNA-positive staining were observed. In histologically normal cells, p53 staining was almost absent and PCNA-positive staining was regularly observed in the lower half of the crypt. In radiation colitis including aberrant glands, cellular proliferation increased and spotted p53 expression was observed. This study suggests that radiation colitis and aberrant glands might possess malignant potential and deeply associate with carcinogenesis of radiation-induced colon cancer. (author)

  15. Radiation-induced bilateral cystic frontal lobe necroses demonstrating a fluid-blood level

    A 41-year-old male developed radiation-induced bilateral cystic frontal lobe necroses after irradiation for an olfactory neuroblastoma. Computed tomography (CT) and magnetic resonance (MR) imaging revealed the lesions, one containing a fluid-blood level on CT scans and niveau formation on MR images. It was proved to be a coagulated hematoma within the cyst at surgery. Such a fluid-blood level in a radiation-induced cyst has never been reported, although hemorrhage frequently accompanies delayed radiation necrosis. Positron emission tomography with multiple tracers may be useful in differentiating cerebral radiation necrosis from tumor recurrence, because of absence of abnormal tracer accumulation. (author)

  16. Radiation-induced carotid artery disease

    Nine patients with atherosclerotic carotid artery disease associated with neck radiation were compared to 40 control patients. The data suggest that significant differences in age, incidence of coronary and peripheral vascular disease, elevated lipids and serum cholesterol, and the angiographic incidence of disseminated atherosclerosis justify the description of radiation-induced carotid disease as a clinical entity. Elevated serum cholesterol and hyperlipidemia may contribute to the development of radiation-induced vascular disease. Successful surgical reconstruction does not appear to be influenced by the prior radiotherapy, although periarterial fibrosis and increased difficulty in separating the plaques from the vascular media was encountered

  17. Radiation-induced cataracts. Glance at some new data

    The radiation-induced cataract has been up to now considered as a quite rare pathology, needing high-dose radiations (beyond a dose threshold roughly estimated at 2 Grays to the lens) consisting mainly in head tumour radiotherapy complications. Several new studies on different exposed populations such as astronauts, Japanese atomic bomb survivors, people undergoing X-ray examinations, Chernobyl accident 'liquidators' as well as data from animal experiments, suggest that dose threshold for detectable opacities as well as for clinical posterior sub-capsular cataract occurring, might be far lower than those previously assumed. Even the existence of a dose threshold is no longer an absolute certitude insofar as radiation-induced cataract pathogenesis might consist not really in a deterministic effect (direct tissue harmful effect, killing or seriously injuring a critical population of cells) as believed until now, but rather in a stochastic effect (genomic damage in target-cells, altered cell division, abnormal lens fibre cell differentiation). More practically, these new data may lead us to reconsider radioprotection of specifically exposed populations : mainly patients and workers. Regarding workers, labour legislation (lens equivalent dose limit of 150 mSv during 12 consecutive months) might be, in the medium term, reassessed downwards. (author)

  18. Chromosomal anomalies in radiation-induced fibrosis in the pig

    R-banded karyotypes were established on fibroblasts from fibrotic tissues derived from experimental fibrosis induced in pigs, either surgically or by 64 Gy of γ-rays from iridium-192. No chromosome aberrations were observed in the surgical fibrosis. In radiation-induced fibrosis, the high frequency of abnormal karyotypes and frequent complexity of the chromosomal rearrangements suggest that the fibroblasts originated either from the 64-Gy area, or from the penumbra, but certainly not from non-irradiated areas. At early passages in vitro, almost all karyotypes were different, demonstrating a multiclonal origin of fibrotic tissue. At late passages (above 24), the situation was quite different, with the persistence of one or two clones only, demonstrating a strong selective pressure occurring in vitro. (author). 23 refs., 2 figs., 2 tabs

  19. Study of microflora status of radiation-induced peripheral blood T cell and its subgroup changes

    Objective: To observe the differences of the radiation-induced peripheral blood T cell and its subgroup changes between SPF and CV rats after nasopharyngeal radiation with gradient doses and explore the microflora factors in the pathogenesis of abnormal radiation-induced immunity status. Methods: 8 from each SPF and CV rats were chosen for oropharyngeal bacteria cultivation and determination and the spleen organ coefficients. The rest were irradiated with 6MX linear accelerator in the nasopharyngeal fields at dose of 0, 10, 20, 30 Gy, 5 in each group. 24 ∼ 36 h later, blood T lymphocytes and their subgroups were detected by FCM. Results: The bacteria of CV rats were pathogen mostly and the one from SPF rats was Proteus mirabilis uniquely. Spleen organ coefficients between two groups showed no statistical difference. CD+3, CD+4 lymphocytes and the ratio of CD+4/ CD+8 of CV rats decreased dramatically after radiation is in close relation with radiation doses while The CD+8 lymphocyte increased a bit. The CD+3, CD+4, CD+8 lymphocytes and the ratio of CD+4/ CD+8 of SPF rats remained in a stable level. Conclusions: There exists the difference of radiation-induced injuries of immune system in relation with different microflora status. Micro-flora plays an important role in the radiation-induced immune system abnormity. (authors)

  20. Radiation-Induced Breast Cancer Incidence and Mortality from Digital Mammography Screening: A Modeling Study

    Miglioretti, Diana L.; Lange, Jane; van den Broek, Jeroen J.; Lee, Christoph I.; van Ravesteyn, Nicolien T.; Ritley, Dominique; Kerlikowske, Karla; Fenton, Joshua J.; Melnikow, Joy; de Koning, Harry J.; Hubbard, Rebecca A.

    2016-01-01

    Background Estimates of radiation-induced breast cancer risk from mammography screening have not previously considered dose exposure variation or diagnostic work-up after abnormal screening. Objective To estimate distributions of radiation-induced breast cancer incidence and mortality from digital mammography screening, considering exposure from screening and diagnostic mammography and dose variation across women. Design Two simulation-modeling approaches using common data on screening mammography from the Breast Cancer Surveillance Consortium and radiation dose from mammography from the Digital Mammographic Imaging Screening Trial. Setting U.S. population. Patients Women aged 40–74 years. Interventions Annual or biennial digital mammography screening from age 40, 45, or 50 until 74. Measurements Lifetime breast cancer deaths averted (benefits) and radiation-induced breast cancer incidence and mortality per 100,000 women screened (harms). Results On average, annual screening of 100,000 women aged 40 to 74 years was projected to induce 125 breast cancers (95% confidence interval [CI]=88–178) leading to 16 deaths (95% CI=11–23) relative to 968 breast cancer deaths averted by early detection from screening. Women exposed at the 95th percentile were projected to develop 246 radiation-induced breast cancers leading to 32 deaths per 100,000 women. Women with large breasts requiring extra views for complete breast examination (8% of population) were projected to have higher radiation-induced breast cancer incidence and mortality (266 cancers, 35 deaths per 100,000 women), compared to women with small or average breasts (113 cancers, 15 deaths per 100,000 women). Biennial screening starting at age 50 reduced risk of radiation-induced cancers 5-fold. Limitations We were unable to estimate years of life lost from radiation-induced breast cancer. Conclusions Radiation-induced breast cancer incidence and mortality from digital mammography screening are impacted by dose

  1. Bile acids in radiation-induced diarrhea

    Radiation-induced bowel disease manifested by debilitating diarrhea is an unfortunate consequence of therapeutic irradiation for pelvic malignancies. Although the mechanism for this diarrhea is not well understood, many believe it is the result of damage to small bowel mucosa and subsequent bile acid malabsorption. Excess amounts of bile acids, especially the dihydroxy components, are known to induce water and electrolyte secretion and increase bowel motility. We have directly measured individual and total bile acids in the stool samples of 11 patients with radiation-induced diarrhea and have found bile acids elevated two to six times normal in eight of them. Our patients with diarrhea and increased bile acids in their stools had prompt improvement when given cholestyramine. They had fewer stools and returned to a more normal life-style

  2. Radiation induced fracture of the scapula

    Riggs, J.H. III; Schultz, G.D.; Hanes, S.A. (Los Angeles College of Chiropractic, Whittier, CA (USA))

    1990-10-01

    A case of radiation induced osteonecrosis resulting in a fracture of the scapula in a 76-yr-old female patient with a history of breast carcinoma is presented. Diagnostic imaging, laboratory recommendations and clinical findings are discussed along with an algorithm for the safe management of patients with a history of cancer and musculoskeletal complaints. This case demonstrates the necessity of a thorough investigation of musculoskeletal complaints in patients with previous bone-seeking carcinomas.

  3. Radiation induced fracture of the scapula

    A case of radiation induced osteonecrosis resulting in a fracture of the scapula in a 76-yr-old female patient with a history of breast carcinoma is presented. Diagnostic imaging, laboratory recommendations and clinical findings are discussed along with an algorithm for the safe management of patients with a history of cancer and musculoskeletal complaints. This case demonstrates the necessity of a thorough investigation of musculoskeletal complaints in patients with previous bone-seeking carcinomas

  4. Study of chemical and radiation induced carcinogenesis

    Chmura, A.

    1995-11-01

    The study of chemical and radiation induced carcinogenesis has up to now based many of its results on the detection of genetic aberrations using the fluorescent in situ hybridization (FISH) technique. FISH is time consuming and this tends to hinder its use for looking at large numbers of samples. We are currently developing new technological advances which will increase the speed, clarity and functionality of the FISH technique. These advances include multi-labeled probes, amplification techniques, and separation techniques.

  5. Radiatively induced Quark and Lepton Mass Model

    Nomura, Takaaki

    2016-01-01

    We propose a radiatively induced quark and lepton mass model in the first and second generation with extra $U(1)$ gauge symmetry and vector-like fermions. Then we analyze the allowed regions which simultaneously satisfy the FCNCs for the quark sector, LFVs including $\\mu-e$ conversion, the quark mass and mixing, and the lepton mass and mixing. Also we estimate the typical value for the $(g-2)_\\mu$ in our model.

  6. A case of radiation-induced glioma

    A case of malignant cerebellar glioma developing 25 years after radiotherapy for pineal tumor is described. The patient is a 40-year-old male, who was admitted to our department with complaints of dizziness and gait disturbance. neurological examinations revealed symptoms involving the left cerebellar hemisphere and cerebellar vermis. CT scan and MRI demonstrated a circularly enhanced tumor which was located in the left cerebellar hemisphere extending to the vermis. The tumor was diagnosed as malignant glioma. In view of the former radiotherapy, this glioma was suspected to have been induced by radiation. The situation conformed to Walker's criteria for radiation-induced tumor. With the patient under general anesthesia, the tumor was subtotally removed by means of suboccipitel craniectomy. Histopathologically, the tumor was diagnosed as astrocytoma, grade 3. Most radiation-induced gliomas are malignant. There seems to be no significant correlation between the radiation dose; the latent period widely varies, ranging from several years to more than 20 years. Even if the radiation dose is small, there still exists the risk that radiation might induce a tumor. It was concluded that the possibility of radiation-induced tumor should be kept in mind whenever radiation therapy is carried out for brain tumors. (author)

  7. Radiation-induced brachial plexopathy: MR imaging

    Wouter van Es, H. [Department of Radiology, University Hospital Utrecht, Heidelberglaan 100, 3584 CX Utrecht (Netherlands); Engelen, A.M. [Department of Radiation Therapy, University Hospital Utrecht, Utrecht (Netherlands); Witkamp, T.D. [Department of Radiology, University Hospital Utrecht, Heidelberglaan 100, 3584 CX Utrecht (Netherlands); Ramos, L.M.P. [Department of Radiology, University Hospital Utrecht, Heidelberglaan 100, 3584 CX Utrecht (Netherlands); Feldberg, M.A.M. [Department of Radiology, University Hospital Utrecht, Heidelberglaan 100, 3584 CX Utrecht (Netherlands)

    1997-05-01

    Objective. To describe the MR imaging appearance of radiation-induced brachial plexopathy. Design. MR imaging was performed in two patients with the clinical diagnosis of radiation-induced brachial plexopathy and in one with surgically proven radiation fibrosis of the brachial plexus. Patients. Three patients who had had radiation therapy to the axilla and supraclavicular region (two with breast carcinoma and one with Hodgkin`s lymphoma) presented with symptoms in the arm and hand. To exclude metastases or tumor recurrence MR imaging was performed. Results and conclusion. In one patient, fibrosis showing low signal intensity was found, while in two patients high signal intensity fibrosis surrounding the brachial plexus was found on the T2-weighted images. In one case gadolinium enhancement of the fibrosis was seen 21 years after radiation therapy. It is concluded that radiation-induced brachial plexopathy can have different MR imaging appearances. We found that radiation fibrosis can have both low or high signal intensities on T2-weighted images, and that fibrosis can enhance even 21 years after radiation therapy. (orig.). With 3 figs.

  8. Radiation-induced gene expression in human subcutaneous fibroblasts is predictive of radiation-induced fibrosis

    Rødningen, Olaug Kristin; Børresen-Dale, Anne-Lise; Alsner, Jan;

    2008-01-01

    BACKGROUND AND PURPOSE: Breast cancer patients show a large variation in normal tissue reactions after ionizing radiation (IR) therapy. One of the most common long-term adverse effects of ionizing radiotherapy is radiation-induced fibrosis (RIF), and several attempts have been made over the last...... years to develop predictive assays for RIF. Our aim was to identify basal and radiation-induced transcriptional profiles in fibroblasts from breast cancer patients that might be related to the individual risk of RIF in these patients. MATERIALS AND METHODS: Fibroblast cell lines from 31 individuals with......-treated fibroblasts. Transcriptional differences in basal and radiation-induced gene expression profiles were investigated using 15K cDNA microarrays, and results analyzed by both SAM and PAM. RESULTS: Sixty differentially expressed genes were identified by applying SAM on 10 patients with the highest risk of RIF and...

  9. Radiation-induced sensitisation of stainless steels

    The book contains the proceedings of a symposium on radiation-induced sensitization of stainless steels, which took place at Berkeley, United Kingdom, 1986. The purpose of the symposium was to examine the mechanism leading to inter-granular corrosion of 20%Cr/25% Ni/Nb stainless steel cladding of AGR fuel following irradiation. Nine papers are presented, of which three are theoretical, two papers are based upon corrosion studies of 20%Cr/25%Ni/Nb steel, and the remaining are concerned with compositional redistribution and its measurement. (U.K.)

  10. Radiation-induced hydrogen transfer in metals

    Tyurin, Yu I.; Vlasov, V. A.; Dolgov, A. S.

    2015-11-01

    The paper presents processes of hydrogen (deuterium) diffusion and release from hydrogen-saturated condensed matters in atomic, molecular and ionized states under the influence of the electron beam and X-ray radiation in the pre-threshold region. The dependence is described between the hydrogen isotope release intensity and the current density and the electron beam energy affecting sample, hydrogen concentration in the material volume and time of radiation exposure to the sample. The energy distribution of the emitted positive ions of hydrogen isotopes is investigated herein. Mechanisms of radiation-induced hydrogen transfer in condensed matters are suggested.

  11. Radiation-induced segregation in titanium alloys

    Radiation-induced segregation (RIS) of V, Mo, Nb, Ta, Zr, and Sn in binary titanium alloys was investigated to test the solute size effect correlation in hcp alloys. Undersize Mo segregates weakly toward the sinks. Nb and Ta, which are slightly oversize in Ti, undergo little or no RIS. Oversize Zr solute in Ti segregates away from the sinks, whereas undersize Ti solute in Zr is enriched at sinks. All of these results are in accord with the solute size effect correlation. Surprisingly, Sn, which is significantly oversize in Ti, appears to segregate very little. The postirradiation annealing of Ti-3V and Ti-8Al-1V-1Mo confirmed that segregation of undersize V toward sinks is radiation-induced. Measurements of temperature and dose dependence in binary and complex alloys showed that the degree of V segregation has a maximum at proportional6000C and obeys parabolic growth kinetics in its early stages but probably saturates at a rather low dose (proportional0.8 dpa). (orig.)

  12. Radiation induced preparation of new multifunctional nanobiowebs

    New poly(vinylidene fluoride) based multi-functional (electroconductive, bioactive and catalytic) nano-biowebs were prepared through gamma radiation induced formation of silica and gold nanoparticles (Au NPs) within electrospun (poly vinylidene fluoride) nanofiberous membranes. The multifunctional membrane is designated as PVdF-silica/Au ESNFM. The morphology of PVdF-silica/Au ESNFM was examined by field emission scanning electron microscopy. The presence of Au particles was confirmed by energy dispersive x-ray analysis. The crystal structure of Au particles and the formation of silica were confirmed by X-ray diffraction analysis. The multi-functionalities (electroconductive, bioactive and catalytic) of the nano-webs were evaluated by cyclic voltammetry. Cytochrome c was immobilized to generate nano-bioweb (PVdF-silica/Au/cyt c ESNFM), which exhibited electrochemical responses to nitrite ions. - Highlights: ► New poly(vinylidene fluoride) based multi-functional (electroconductive, bioactive and catalytic) nano-biowebs were prepared through gamma radiation induced processes. ► The multi-functionalities (electroconductive, bioactive and catalytic) of the nano-webs are evaluated. ► Incorporation of gold nanoparticles into electrospun membranes imparts electroactivity and bioelectrocatalytic properties.

  13. Radiation induced conductivity in space dielectric materials

    The radiation-induced conductivity of some polymers was described mainly in literature by a competition between ionization, trapping/detrapping, and recombination processes or by radiation assisted ageing mechanisms. Our aim is to revise the effect of the aforementioned mechanisms on the complex evolution of Teflon® FEP under space representative ionizing radiation. Through the definition of a new experimental protocol, revealing the effect of radiation dose and relaxation time, we have been able to demonstrate that the trapping/recombination model devised in this study agrees correctly with the observed experimental phenomenology at qualitative level and allows describing very well the evolution of radiation induced conductivity with irradiation time (or received radiation dose). According to this model, the complex behavior observed on Teflon® FEP may be basically ascribed to the competition between electron/hole pairs generation and recombination: electrons are deeply trapped and act as recombination centers for free holes. Relaxation effects have been characterized through successive irradiations steps and have been again well described with the defined model at qualitative level: recombination centers created by the irradiation induce long term alteration on the electric properties, especially the effective bulk conductivity. One-month relaxation does not allow a complete recovery of the material initial charging behavior

  14. Radiation- induced aneuploidy in mammalian germ cells

    The ability of ionizing radiation to induce aneuploidy in mammalian germ cells has been investigated experimentally in the laboratory mouse using a variety of cytogenetic and genetic methods. These studies have provided unambiguous evidence of induced nondisjunction in both male and female germ cells when the effect of irradiation is screened in meiotic cells or preimplantation embryos. In contrast, however, cytogenetic analyses of post-implantation embryos and genetic assays for induced chromosome gains have not found a significant radiation effect. These apparently contradictory findings may be reconciled if (a) radiation induces tertiary rather than primary trisomy, or (b) induces embryo-lethal genetic damage, such as deletions, in addition to numerical anomalies. Either or both of these explanations may account for the apparent loss during gestation of radiation-induced trisomic embryos. Extrapolating from the information so far available, it seems unlikely that environmental exposure to low doses if low dose rate radiation will result in a detectable increase in the rate of aneuploidy in the human population. (author)

  15. Complicated biallelic inactivation of Pten in radiation-induced mouse thymic lymphomas

    Inactivation of the phosphatase and tensin homolog gene (Pten) occurs via multiple tissue-dependent mechanisms including epigenetic silencing, point mutations, insertions, and deletions. Although frequent loss of heterozygosity around the Pten locus and plausible involvement of epigenetic silencing have been reported in radiation-induced thymic lymphomas, the proportion of lymphomas with inactivated Pten and the spectrum of causal aberrations have not been extensively characterized. Here, we assessed the mode of Pten inactivation by comprehensive analysis of the expression and alteration of Pten in 23 radiation-induced thymic lymphomas developed in B6C3F1 mice. We found no evidence for methylation-associated silencing of Pten; rather, complex structural abnormalities comprised of missense and nonsense mutations, 1- and 3-bp insertions, and focal deletions were identified in 8 of 23 lymphomas (35%). Sequencing of deletion breakpoints suggested that aberrant V(D)J recombination and microhomology-mediated rearrangement were responsible for the focal deletions. Seven of the 8 lymphomas had biallelic alterations, and 4 of them did not express Pten protein. These Pten aberrations coincided with downstream Akt phosphorylation. In conclusion, we demonstrate that Pten inactivation is frequently biallelic and is caused by a variety of structural abnormalities (rather than by epigenetic silencing) and is involved in radiation-induced lymphomagenesis.

  16. Role of neurotensin in radiation-induced hypothermia in rats

    Kandasamy, S.B.; Hunt, W.A.; Harris, A.H. (Armed Forces Radiobiology Research Institute, Bethesda, MD (USA))

    1991-05-01

    The role of neurotensin in radiation-induced hypothermia was examined. Intracerebroventricular (ICV) administration of neurotensin produced dose-dependent hypothermia. Histamine appears to mediate neurotensin-induced hypothermia because the mast cell stabilizer disodium cromoglycate and antihistamines blocked the hypothermic effects of neurotensin. An ICV pretreatment with neurotensin antibody attenuated neurotensin-induced hypothermia, but did not attenuate radiation-induced hypothermia, suggesting that radiation-induced hypothermia was not mediated by neurotensin.

  17. Radiation-induced doping of conducting polymers

    Conducting polymers have the potential form many applications in electronics. The various patterns of doped regions of conducting polymers should be generated for the applications. Doping of conducting polymers is achieved by contact of the polymer with dopant or electrochemically. By these methods, doping occurs in the entire area exposed to the dopant. It is necessary to combine these doping techniques with lithography for achieving the patterned doping. Radiation-induced doping effects of conducting polymers have been reported. The doping is performed by irradiation of polymers in an atmosphere of gases, which do not react without irradiation, such as CH3Br, SF6, and N2O. If only the irradiated area was doped, patterned doping could be achieved without using lithography technique. We have elucidated the mechanism of the radiation-induced doping. The electrical conductivity was increased by irradiation the gas near the polymer film without irradiating the film itself. This result indicates that dopants were generated upon irradiation in the gas phase and the dopants react with the polymer. Hence, the pattern of doping is blurred by this method. We then developed another method of radiation-induced doping. Solid dopant precursor was coated on the polymer, and irradiation was performed. Figure 1 shows the results for poly(3-octylhitophene)(P3OT) by this method. A film of poly(3-octylthiophene) was prepared by spin coating from a solution of tetrahydrofuran on a quartz plate. The thickness of the film was approximately 100 nm. The polymer film was dried overnight at 80 degree C in a vacuum, and Au electrodes were evaporated on the films for electrical conductivity measurements. Saturated solution of 1,2,5,6,9,10-hexabromocyclododecane (HBCD) in 1-bromopropane was dropped on the film and dried at room temperature in a vacuum. The film was put in a vacuum chamber, which has a 0.2-mm-thick Be window. X rays entered through the Be window, and the films were irradiated

  18. Management of radiation-induced rectal bleeding.

    Laterza, Liboria; Cecinato, Paolo; Guido, Alessandra; Mussetto, Alessandro; Fuccio, Lorenzo

    2013-11-01

    Pelvic radiation disease is one of the major complication after radiotherapy for pelvic cancers. The most commonly reported symptom is rectal bleeding which affects patients' quality of life. Therapeutic strategies for rectal bleeding are generally ignored and include medical, endoscopic, and hyperbaric oxygen treatments. Most cases of radiation-induced bleeding are mild and self-limiting, and treatment is normally not indicated. In cases of clinically significant bleeding (i.e. anaemia), medical therapies, including stool softeners, sucralfate enemas, and metronidazole, should be considered as first-line treatment options. In cases of failure, endoscopic therapy, mainly represented by argon plasma coagulation and hyperbaric oxygen treatments, are valid and complementary second-line treatment strategies. Although current treatment options are not always supported by high-quality studies, patients should be reassured that treatment options exist and success is achieved in most cases if the patient is referred to a dedicated centre. PMID:24101202

  19. Radiation-induced brachial plexus paralysis

    Fifteen patients with radiation-induced brachial plexus paralysis were studied. Thirteen women had been treated for breast cancer. Two men developed symptoms and signs following radiation therapy for lung cancer. The brachial plexus paralysis initially was not static and progressed, but spontaneous arrest with permanent residual paralysis was seen in three patients. Three were noted to have intractable pain, but the major complaint of the remaining 12 was the inability to use their hands. The ten patients on whom an earlier operation directed at the brachial plexus had been performed were not relieved. Two of these were later considered excellent candidates for a tendon transfer in the hand. One did not desire surgery. The other underwent operation and showed marked improvement of her grasp and general hand function

  20. Radiation-induced spinal cord hemorrhage (hematomyelia

    Amit Agarwal

    2014-12-01

    Full Text Available Intraspinal hemorrhage is very rare and intramedullary hemorrhage, also called hematomyelia, is the rarest form of intraspinal hemorrhage, usually related to trauma. Spinal vascular malformations such intradural arteriovenous malformations are the most common cause of atraumatic hematomyelia. Other considerations include warfarin or heparin anticoagulation, bleeding disorders, spinal cord tumors. Radiation-induced hematomyelia of the cord is exceedingly rare with only one case in literature to date. We report the case of an 8 year old girl with Ewing’s sarcoma of the thoracic vertebra, under radiation therapy, presenting with hematomyelia. We describe the clinical course, the findings on imaging studies and the available information in the literature. Recognition of the clinical pattern of spinal cord injury should lead clinicians to perform imaging studies to evaluate for compressive etiologies.

  1. Radiation-induced mutation at minisatellite loci

    We are studying the radiation-induced increase of mutation rate in minisatellite loci in mice and humans. Minisatellite mutations were scored by multilocus DNA fingerprint analysis in the progeny of γ-irradiated and non-irradiated mice. The frequency of mutation in offspring of irradiated males was 1.7 higher that in the control group. Germline mutation at human minisatellite loci was studied among children born in heavily polluted areas of the Mogilev district of Belarus after the Chernobyl accident and in a control population. The frequency of mutation assayed both by DNA fingerprinting and by eight single locus probes was found to be two times higher in the exposed families than in the control group. Furthermore, mutation rate was correlated with the parental radiation dose for chronic exposure 137Cs, consistent with radiation-induction of germline mutation. The potential use of minisatellites in monitoring germline mutation in humans will be discussed

  2. Radiation-induced grafting onto wool

    Radiation-induced grafting tests were done on single wool fibres. Different vinyl monomers were used for this purpose and they were grafted in twenty different solvents which were selected for their swelling effiency and solvent parameters. The tests were done once with and once without the addition of water. The presence of water causes the polymer uptake to increase considerably. Formic acid/methanol and methanol were found to be the most suitable solvent systems, as they have the highest hydrogen-bond interaction effiency. The moisture uptake of wool depends on the hydrophily and hydrophoby of the grafted polymers. The single-fibre tests serve as a basis for analogous grafting tests on wool fabrics. The permanent- press was improved by graftng with hydrophoric polymers and polymers with a high glass-transition temperature

  3. Radiation-induced mutations in mammals

    The aims of the proposed project are to provide a better basis for extrapolation of animal data to man. Genetic endpoint, strain and species comparisons are made, which will provide critical experimental data regarding strategies in extrapolating laboratory animal data to man. Experiments were conducted to systematically compare the spontaneous and radiation-induced mutation rates for recessive specific-locus, dominant cataract and enzyme activity alleles in the mouse as well as a comparison of the mutation rate in the mouse and hamster for dominant cataract and enzyme activity alleles. The comparison of the radiation-dose response for recessive specific-locus and dominant cataract mutations are extended. Selected mutations are characterized at the genetic, biochemical and molecular levels. (R.P.) 5 refs., 3 tabs

  4. Radiation-induced emulsion polymerization of tetrafluoroethylene

    The radiation-induced emulsifier-free emulsion polymerization of tetrafluoroethylene (TFE) has been studied at initial pressure 2 - 25 kg/cm2 and temperature 300 - 1100C for dose rate 0.57 x 104 - 3.0 x 104 rad/hr. Polytetrafluoroethylene (PTFE), a hydrophobic polymer, forms as a stable latex in the absence of an emulsifier. Stability of the latex is governed by the dose rate/TFE pressure ratio; it increases with sufficient TFE monomer. PTFE particles produced in this polymerization system are stable due to the carboxyl end groups and adsorption of OH- and HF on the particles. PTFE latex of molecular weight higher than 2 x 107 is obtained by addition of a radical scavenger such as hydroquinone. The molecular weight of PTFE can be measured from the heat of crystallization conveniently with high reliability, which was found in the course of study on the melting and crystallization behavior. (author)

  5. Gamma-radiation-induced grafting onto wool

    Radiation-induced grafting studies have been carried out on loose wool fibres. Different vinyl monomers were used and they were grafted in different solvents which were selected on the basis of their swelling efficiency and solubility parameters. The treatments were performed once with and once without the addition of water. The presence of water caused the polymer uptake to increase considerably. Formic acid/methanol and methanol accelerate the grafting process best, since they have the highest hydrogen-bond interaction efficiency. The moisture uptake of grafted wool decreases. X-ray and differential scanning calorimetry tests show unambiguously that grafting occurs in different morphological areas, depending on the type of polymer. The single fibre studies served as basis for analogous tests on wool fabrics (Part II). (author)

  6. Radiation-induced electron migration along DNA

    Radiation-induced electron migration along DNA is a mechanism by which randomly produced stochastic energy deposition events can lead to nonrandom types of damage along DNA manifested distal to the sites of the initial energy deposition. Electron migration along DNA is significantly influenced by the DNA base sequence and DNA conformation. Migration along 7 base pairs in oligonucleotides containing guanine bases was observed for oligonucleotides irradiated in solution which compares to average migration distances of 6 to 10 bases for Escherichia coli DNA irradiated in solution and 5.5 base pairs for Escherichia coli DNA irradiated in cells. Evidence also suggests that electron migration can occur preferentially in the 5' to 3' direction along DNA. Our continued efforts will provide information regarding the contribution of electron transfer along DNA to formation of locally multiply damaged sites created in DNA by exposure to ionizing radiation

  7. Radiation-induced premature menopause: a misconception

    Purpose: To disprove the common view that women who have undergone irradiation to fields excluding the pelvis are at risk for radiation-induced premature menopause, we reviewed menstrual function and fertility among women treated with subtotal lymphoid irradiation for Hodgkin's Disease. Methods and Materials: Treatment and follow-up records of all women less than age 50 at the time of diagnosis of Stage I or II supradiaphragmatic Hodgkin's Disease, treated with subtotal lymphoid irradiation alone and enrolled in radiotherapy trials from 1967 to 1985, were reviewed. In addition, patients were surveyed regarding their menstrual status and fertility history. Results: Thirty-six women, aged 10 to 40 years, with normal menstrual function at the time of Hodgkin's diagnosis, were identified. Mean follow-up was 14 years, with a range of 1.25-22.75 years. The average radiation dose to mantle and paraaortic fields was 40-44 Gy; the calculated scatter radiation dose to the pelvis at the ovaries was 3.2 Gy. There were 38 pregnancies in 18 women; all offspring are normal. One of 36 women (2.7%) experienced premature menopause. The reported rate of premature menopause in women who have not undergone irradiation is 1-3%; not significantly different than the rate in our study. There is a syndrome whereby antibodies to several endocrine organs occur (including the ovary), which is associated with premature ovarian failure. This syndrome may be associated with prior radiation to the thyroid, such as that given by mantle-irradiation for Hodgkin's Disease. We report such a case. Conclusion: There is little risk of premature menopause in women treated with radiation fields that exclude the pelvis. Women with presumed radiation-induced premature menopause warrant an evaluation to exclude other causes of ovarian failure, such as autoimmune disorders

  8. Radiation-induced damage to DNA

    This short survey focuses on the main radiation-induced base lesions that have been identified within cellular DNA. For this purpose, sensitive assays that are aimed at measuring a few modifications per 107 normal bases were set-up. In that respect high performance liquid chromatography - tandem mass spectrometry (CLHP-MS/MS) was found to be able to single out the formation of 9 oxidized nucleosides and two modified nucleo-bases out of the 70 oxidative base lesions that have been identified in model systems. As a striking result, it was found that in the DNA of γ-irradiated human monocytes, the formamide-pyrimidine derivative of guanine is produced in a higher yield than the ubiquitous 8-oxo-7,8-dihydro-guanine damage, both arising from the same radical precursor. However, relatively high doses of ionizing radiation (> 20 Gy) have to be applied in order to detect an increase in the level of the damage. This is due to the low efficiency for both low and high LET radiations to generate oxidative damage to DNA on one hand and the occurrence of artifactual oxidation of the overwhelming normal bases during DNA extraction on the other hand. Interestingly, a modified comet assays that involves the combined use of the alkaline single gel electrophoretic technique and DNA repair N-glycosylases has allowed the detection of three main types of radiation-induced damage within the dose range 0.3 Gy -10 Gy. It appears that the total of frank DNA strand breaks and alkali-labile sites is similar to the sum of oxidized pyrimidine bases and modified purine bases that are recognized by the endonuclease Ill protein and the formamide-pyrimidine DNA N-glycosylase respectively. (author)

  9. Early corticosteroid administration in experimental radiation-induced heart disease

    The ability of dexamethasone (DEX) to reduce the severity of the late stage of radiation-induced heart disease (RIHD) was assessed in 25 New Zealand white rabbits. Ten rabbits served as unirradiated controls (CONT). In Group A, seven rabbits received intravenous DEX prior to irradiation and every 24 hours for three consecutive days. DEX was not administered to the eight rabbits in Group B. At 100 days postirradiation, the severity of the late state was determined by microscopic examination (MICRO) for myocardial fibrosis and determination of myocardial hydroxyproline content (MHP). Myocardial fibrosis was evident in groups A (40%) and B (80%) while none was present in CONT by MICRO. One rabbit in Group B with no fibrosis by MICRO had abnormally increased MHP. MHP was significantly increased in Groups A and B, as compared to CONT (p < 0.01). In addition to less fibrosis by MICRO, Group A demonstrated a significant reduction of MHP when compared to Group B (p < 0.05). Determination of MHP may be superior to MICRO in the detection of the late stage of RIHD. Also, early DEX administration appears to reduce myocardial collagen content (fibrosis) in this experimental model

  10. Radiation induced thyroid neoplasms 1920 to 1987: A vanishing problem

    Mehta, M.P.; Goetowski, P.G.; Kinsella, T.J.

    1989-06-01

    Radiation for benign diseases has been implicated as an etiologic factor in thyroid cancer. From 1930-60, over 2 million children may have been exposed to therapeutic radiation and it is estimated that up to 7% may develop thyroid cancer after a 5-40 year latency. Thyroid stimulating hormone, secondary to radioinduced hypothyroidism, has been implicated as causative in animals. Such data has led to expensive screening programs in high risk patients. Because of a decline in irradiation for benign diseases in children over the last 2 decades, we questioned whether the incidence of radiation induced thyroid neoplasms (RITN) was also decreasing. Twenty-six of 227 patients (11%) with thyroid malignancies seen at our institution from 1974-87 had a history of previous head and neck irradiation. These included 13 papillary, 3 follicular, and 7 mixed carcinomas as well as 2 lymphomas and 1 synovial cell sarcoma. None of these 26 patients had abnormal thyroid function tests at presentation. Mean latency from irradiation to the diagnosis of thyroid cancer was 25.4 years (6-55 year range). Compared to the reported increasing incidence of RITN from 1940-70, there appears to be a significant decrease since 1970. Based on our analysis, the use of expensive screening programs in high risk populations may no longer be warranted. Additionally, the routine use of thyroid replacement in previously irradiated chemically hypothyroid patients is not recommended.30 references.

  11. Radiation induced thyroid neoplasms 1920 to 1987: A vanishing problem

    Radiation for benign diseases has been implicated as an etiologic factor in thyroid cancer. From 1930-60, over 2 million children may have been exposed to therapeutic radiation and it is estimated that up to 7% may develop thyroid cancer after a 5-40 year latency. Thyroid stimulating hormone, secondary to radioinduced hypothyroidism, has been implicated as causative in animals. Such data has led to expensive screening programs in high risk patients. Because of a decline in irradiation for benign diseases in children over the last 2 decades, we questioned whether the incidence of radiation induced thyroid neoplasms (RITN) was also decreasing. Twenty-six of 227 patients (11%) with thyroid malignancies seen at our institution from 1974-87 had a history of previous head and neck irradiation. These included 13 papillary, 3 follicular, and 7 mixed carcinomas as well as 2 lymphomas and 1 synovial cell sarcoma. None of these 26 patients had abnormal thyroid function tests at presentation. Mean latency from irradiation to the diagnosis of thyroid cancer was 25.4 years (6-55 year range). Compared to the reported increasing incidence of RITN from 1940-70, there appears to be a significant decrease since 1970. Based on our analysis, the use of expensive screening programs in high risk populations may no longer be warranted. Additionally, the routine use of thyroid replacement in previously irradiated chemically hypothyroid patients is not recommended.30 references

  12. The process and promotion of radiation-induced cell death

    Radiation-induced cell death is divided into reproductive and interphase death, whose process can be revealed by time-lapse observations. Pedigree analyses of progenies derived from a surviving progenitor cell have shown that moribund cells appear in clusters among cells which are apparently undamaged (lethal sectoring). Sister cell fusion, which likely results from chromosome bridge, is the most frequently observed cell abnormality leading to reproductive death. While interphase death does not occur unless the dose exceeds 10 Gy for low LET radiation such as X-rays, high-LET radiation is very effective at inducing interphase death (RBE: ≅3 at 230 keV/μm). Expression or fixation of potentially lethal damage (PLD) is closely associated with cell cycle events and enhanced by inducing premature chromosome condensation (PCC) at a nonpermissive temperature in tsBN2 cells with a ts-defect in RCC1 protein (a regulator of chromatin condensation) which monitors the completion of DNA replication. Furthermore, higher-order structural changes in nuclear matrix such as induced by leptomycin B, an inhibitor of CRM1 (chromosome region maintenance) protein, also play an important role in the fixation of PLD. (author)

  13. Radiation-induced apoptosis and developmental disturbance of the brain

    Inouye, Minoru [Nagoya Univ. (Japan). Research Inst. of Environmental Medicine

    1995-03-01

    The developing mammalian brain is highly susceptible to ionizing radiation. A significant increase in small head size and mental retardation has been noted in prenatally exposed survivors of the atomic bombing, with the highest risk in those exposed during 8-15 weeks after fertilization. This stage corresponds to day 13 of pregnancy for mice and day 15 for rats in terms of brain development. The initial damage produced by radiation at this stage is cell death in the ventricular zone (VZ) of the brain mantle, the radiosensitive germinal cell population. During histogenesis of the cerebellum the external granular layer (EGL) is also radiosensitive. Although extensive cell death results in microcephaly and histological abnormlity, both VZ and EGL have an ability to recover from a considerable cell loss and form the normal structure of the central nervous system. The number of cell deaths to induce tissue abnormalities in adult brain rises in the range of 15-25% of the germinal cell population; and the threshold doses are about 0.3 Gy for cerebral defects and 1 Gy for cerebellar anomalies in both mice and rats. A similar threshold level is suggested in human cases in induction of mental retardation. Radiation-induced cell death in the VZ and EGL has been revealed as apoptosis, by the nuclear and cytoplasmic condensation, transglutaminase activation, required macromolecular synthesis, and internucleosomal DNA cleavage. Apoptosis of the germinal cell is assumed to eliminate acquired genetic damage. Once an abnormality in DNA has been induced and fixed in a germinal cell, it would be greatly amplified during future proliferation. These cells would commit suicide when injured for replacement by healthy cells, rather than undertake DNA repair. In fact they show very slow repair of cellular damage. Thus the high sensitivity of undifferentiated neural cells to the lethal effect of radiation may constitute a biological defense mechanism. (author) 69 refs.

  14. Radiation induced mitochondrial biogenesis: limitations of metabolic viability based assays in measuring radiation induced cell death

    Many techniques based on metabolic viability of cells employing MTT and MTS assay are being widely used to measure the radiation and chemotherapeutics induced cell death, because of their high throughput capability. These assays are based on mitochondrial potential of cells to convert the substrate in to measurable products and remain dependent on this notion that all the cells untreated and treated will have equal mitochondrial content and metabolic potential. However, it is increasingly becoming clear that treatment induced changes in both mitochondrial content and metabolism can influence the metabolic viability of cells and radiation is a potential mitochondrial biogenesis inducer. Therefore, we tested if metabolic viability based assays are true measure of radiation induced cell death using the widely used cell lines like RAW264.7, HEK293, NIH3T3, J774.1, BMG-1, MDAMB231, MCF-7, A549 and HeLa. Cells were irradiated with gamma rays (60Co) and enumerated cell numbers (by hemocytometer) and metabolic viability using MTT assay at 24 and 48 hours after exposure. At all the absorbed doses (0-5 Gy), the extent of reduction in cell number was found to be larger than the decrease in formazan formation in all the cell lines tested. Further, this difference in the cell number and formazan formation varied significantly among the cell lines. To test if the increased formazan formation is due to increased mitochondrial content per cell, we analyzed the radiation induced mitochondrial biogenesis using mitochondria specific dye mitotracker red and found a 1.5 to 2 fold increase in mitochondrial content. These findings suggest that radiation induces mitochondrial biogenesis that enhances the metabolic potential leading to increased formazan formation. Therefore, conclusions drawn on radiation induced cytotoxicity based on metabolic viability assays are likely to be erroneous as it may not correlate with growth inhibition and/or loss of clonogenic survival. (author)

  15. Radiation-induced cancer in Japan

    Yamashita, Shoji; Sekizuka, Eiichi [National Saitama Hospital, Wako (Japan); Yamashita, Hisao [Keio Cancer Center, Tokyo (Japan); Takami, Akira [Yamawaki Coll., Tokyo (Japan); Kubo, Atsushi [Keio Univ., Tokyo (Japan). School of Medicine

    2001-12-01

    Results of two questionnaire surveys on radiation-induced malignant tumors conducted in 1977 and 1984 in Japan are briefly summarized. A total of 234 universities and general hospitals (139 in 1977, and 95 in 1984) responded and provided data from 1945 to 1977 and from 1978 to 1984. The number of patients with benign disease who developed secondary malignant tumors following radiation therapy was 150 in the first survey (1977) and 86 in the second survey (1984). The underlying benign diseases of these patients included tuberculous lymphadenitis, skin disease, hemangioma, and thyroid disease, and the most frequent radiation-induced malignant tumors in these patients were malignant tumors of the pharynx (80), cancer of the larynx (26), malignant tumors of the thyroid gland (22), cancer of the esophagus (219), and skin cancer (21). In patients with head and neck diseases the highest correlation between underlying benign disease and radiation-induced malignant tumors was between cervical tuberculous lymphadenitis and tumors of the pharynx (67 patients), followed by cancer of the larynx (19), and malignant tumors of the thyroid gland (11). There were also correlations between thyroid disease and malignant tumors of the thyroid gland (8 patients), hemangioma and skin cancer (7), and skin disease and skin cancer (8). The ratio of the observed values to predicted values (O/E ratio) in these patients was highest for cancer of the pharynxy (118), followed by cancer of the parotid gland (42), skin cancer (31), cancer of the esophagus (22), malignant tumors of the thyroid gland (21), and cancer of the larynx (16). The number of patients with malignant tumors who developed secondary malignant tumors following radiation therapy was 140 in 1977 and 108 in 1984, and the underlying malignant tumors in these patients included tumors of the uterus (106), breast (32), and head and neck (80). The most frequent secondary malignant tumors were soft tissue tumors, followed by leukemia

  16. Gamma Radiation-Induced Template Polymerization Technique

    Gamma radiation induced copolymerization of acrylamide sodiumacrylate (AM-AANa) in the presence and absence of the polymer additive was studied at low monomer concentration(1.4M/l). The results showed that the exponents of the dose rate for the polymerization rate was found to be 1.3 and 1.4 in the absence and in the presence of the polymer additive respectively. The molecular weight of the formed polymer increased by addition of the polymer to the system. In the presence of the polymer the comonomers polymerize on the added polymer. In the absence of the added polymer the comonomers polymerize according to the copolymerization process at the initial stage of the copolymerization. While at high conversion the residual comonomers polymerize on the formed macromolecular chains of the produced polymer. These studies showed that the copolymerization in the presence of added polymer is completely template copolymerization while in the absence of the polymer the copolymerization process is only template process with a high conversion

  17. Radiation-induced polymerization of acrylated systems

    Complete text of publication follows. It has been generally accepted that ionizing radiation induces free radical polymerization in acrylate compounds. It is also reported that, following primary ionization events, acrylates and methacrylates scavenge thermalized electrons to give rise to radical anions and radical cations, which undergo reactions producing the corresponding free radicals. Acrylates have received the most attention in radiation curable pressure sensitive adhesives (PSAs). 2-EHA is well known for its unique pressure-sensitive adhesive properties. An understanding of its primary mechanism of polymerization is of industrial as well as fundamental interest. High entanglement and high molecular weight between crosslinks are crucial for the high shear and peel strength, required of PSAs. Such polymers may be formed using thermal and UV-initiation in solvent or emulsion. Electron beam can also provide these properties when the monomer is polymerized at moderate dose rates and at low temperature. Pulsed electron beam provides a special advantage under conditions where the dose per pulse is below the threshold for overlap (ca. 40 Gy/pulse) and the pulse rate is high enough (>1 kHz) to maintain a quasi-heterogeneous mode at high doses rates. Maintaining low temperature in the early stages of polymerization is important in achieving good properties

  18. Radiation induced mutations for breeding of sorghum

    Several sorghum cultivars of Mali were irradiated with different doses of gamma rays and compared with the Caudatum types. Radio-sensitivity studies suggested that the local types were less sensitive to radiation than the introduced types. Whereas the local varieties survived dose of 300 Gy, in Caudatum types, seed germination and growth were significantly reduced at 200 Gy. Several agronomically important mutants were obtained among the progeny of the local types. Some of the mutants were shorter and had improved panicle characteristics. Radiation-induced variation was observed in several characters such as plant height, resistance to lodging, plant architecture, drought tolerance, panicle length and compactness, seed size and color, seed quality (viterous or floury) and protein content, glume color and structure, flowering data (early and late maturity), and tillering capacity. One mutant was drought tolerant. Promising mutants were selected and are presently under evaluation in the National List Trials to confirm their potential and future release. Selected variants have been also crossed with local types to obtain promising material. (author). 8 refs, 2 tabs

  19. Radiation-induced cranial nerve palsy

    Twenty-five patients with 35 cranial nerve palsies were seen at the Fondation Curie during follow-up after radical radiotherapy for head and neck tumors. The twelfth nerve was involved in 19 cases, the tenth in nine, and the eleventh in five; the fifth and second nerves were involved once each and in the same patient. The twelfth nerve was involved alone in 16 patients and the tenth nerve alone in three, with multiple nerves involved in the remaining six patients. The palsy was noted from 12 to 145 months after diagnosis of the tumor. The latency period could be correlated with dose so that the least square fit equation representing NSD vs delay is NSD = 2598--Delay (in months) x 4.6, with a correlation coefficient of -0.58. The distinction between tumor recurrence and radiation-induced nerve palsy is critical. It can often be inferred from the latency period but must be confirmed by observation over a period of time

  20. Retroviruses in radiation-induced lymphomas

    The nucleotide sequence of RadLV/VL3(T+L+), the thymotropic and leukemogenic entity of the in-vitro propagated radiation leukemia virus complex (RadLV/VL3), is that of a recombinant retrovirus. The gag, pol and most of the env gene are very similar to the homologous regions of Akv MuLV. The 3' end of the env gene and the LTR appear to have derived from a xenotropic MuLV. However, the LTR has acquired a feature shared by other lymphomagenic MuLVs. This feature consists in sequence rearrangements resulting in the generation of presumed enhancer elements. RadLV/VL3(T+L+)-specific proviral sequences were found adjacent to the c-myc gene in several virus-induced thymic lymphomas of the rat, suggesting that the enhancer elements might play a role in lymphomagenesis. However, it was found that the presence of a provirus at a specific DNA site can lead to an in-vitro growth advantage and to clonal cell selection independently of a lymphomagenic process. The authors conclude from this observation that clonal appearance of an integrated provirus in cultured radiogenic lymphoma cells does not necessarily reflect a viral induction of radiation-induced leukemogenesis. (author)

  1. Radiation-induced gene expression in human subcutaneous fibroblasts is predictive of radiation-induced fibrosis

    Background and purpose: Breast cancer patients show a large variation in normal tissue reactions after ionizing radiation (IR) therapy. One of the most common long-term adverse effects of ionizing radiotherapy is radiation-induced fibrosis (RIF), and several attempts have been made over the last years to develop predictive assays for RIF. Our aim was to identify basal and radiation-induced transcriptional profiles in fibroblasts from breast cancer patients that might be related to the individual risk of RIF in these patients. Materials and methods: Fibroblast cell lines from 31 individuals with variable risk of RIF (grouped into five classes from low to high risk) were irradiated with two different schemes: 1 x 3.5 Gy with RNA isolated 2 and 24 h after irradiation, and a fractionated scheme with 3 x 3.5 Gy in intervals of 24 h with RNA isolated 2 h after the last dose. RNA was also isolated from non-treated fibroblasts. Transcriptional differences in basal and radiation-induced gene expression profiles were investigated using 15K cDNA microarrays, and results analyzed by both SAM and PAM. Results: Sixty differentially expressed genes were identified by applying SAM on 10 patients with the highest risk of RIF and the four patients with the lowest risk of RIF after the fractionated scheme. The genes were associated with known functions in processes like apoptosis, extracellular matrix remodelling/cell adhesion, proliferation and ROS scavenging. A minimum set of 18 genes were identified that could differentiate high risk from low risk-patients after the fractionated scheme. Conclusions: The classifier of 18 genes may provide basis for a predictive assay for normal tissue reactions after radiotherapy, and provide new insight into the molecular mechanisms of RIF

  2. Explanation of diagnostic criteria for radiation-induced liver diseases

    National occupational health standard-Diagnostic Criteria for Radiation-Induced Liver Diseases has been passed by the committee of diagnostic criteria for radiation disease and in line for approval by the Ministry of Health. Based on the extensive research of literature, this standard was enacted according to the relevant laws and regulations. It is mainly used for diagnosis of radiation-induced liver diseases, and it also can serve as a guide to diagnose liver disease induced by medical radiation. To implement this standard, and to diagnose and treat the radiation-induced liver diseases patient correctly and promptly, the contents of this standard were interpreted in this article. (authors)

  3. Radiation induced hepatic lesions and their amelioration by Rosemarinus oficinalis

    autopsy interval (i.e. 30 days), only in experimental group. On contrary, abnormal hepatocytes increased up to day 5 after irradiation. Binucleated hepatocytes showed a biphasic mode of elevation after irradiation, first on day 2 then on day 10 post-treatment in both the groups, but the same was comparatively less marked in experimental group. Several radiation induced hepatic lesions were also visualized in both the groups, but in ROE + radiation treated group, the degree of damage was found to be considerably lesser and the recovery from such lesions was much faster to regain the normal architecture of liver. Hence, the results from the present study suggest that Rosemarinus officinalis leaves extract pretreatment provides protection against radiation-induced histopathological alterations in liver of mammals. (author)

  4. Hazard of the radiation induced thyroid cancer

    The level of thyroid cancer in Belarus before Chernobyl accident was low and made in different age and sex groups 0,03-2,5 (male) and 0,1-3,9 (female) per 100000 correspondingly. Different risk factors, which can influence the thyroid cancer development, are being taken into account. They are the factors of environment (strong external irradiation, long-time irradiation for medical purposes or in result of disaster), endo gen factors (hormonal, reproductive, genetic predisposition), some medicinal preparations and other. The protective effect of vegetable and fish consumption was found out. Among the factors of thyroid cancer development one of the most important is radiation. There is a point of view, which assumes that one of the reasons of thyroid cancer cases increase among the population of developed countries is increase of radiation induced thyroid cancer. The results of first research testify the influence of radiation factor on thyroid cancer development. During the period 1920 -1960 in the USA X-ray therapy was applied for the treatment of different good-quality diseases. Thyroid got in the zone of irradiation during the complex treatment with using of radiation. The results of the research of 1970 revealed that 70% of children with thyroid cancer were exposed to radiation in children's age. The subsequent researches of by-effects from the side of a thyroid at beam therapy of various diseases alongside with the results of the estimation of consequences of inhabitants of Hiroshima and Nagasaki irradiation owing to nuclear bombardment have shown the influence of irradiation of a thyroid on cancer development. High quantity of radio-epidemiological researches was directed to the studying of the consequences of thyroid external irradiation at young age. In all carried out researches the quantity of observed thyroid cancer cases among irradiated people has exceeded number of expected. The influence of thyroid internal irradiation by I-131 at young age was

  5. Radiation-induced carotid artery atherosclerosis

    Purpose: Carotid arteries frequently receive significant doses of radiation as collateral structures in the treatment of malignant diseases. Vascular injury following treatment may result in carotid artery stenosis (CAS) and increased risk of stroke and transient ischaemic attack (TIA). This systematic review examines the effect of radiotherapy (RT) on the carotid arteries, looking at the incidence of stroke in patients receiving neck radiotherapy. In addition, we consider possible surrogate endpoints such as CAS and carotid intima-medial thickness (CIMT) and summarise the evidence for radiation-induced carotid atherosclerosis. Materials and methods: From 853 references, 34 articles met the criteria for inclusion in this systematic review. These papers described 9 studies investigating the incidence of stroke/TIA in irradiated patients, 11 looking at CAS, and 14 examining CIMT. Results: The majority of studies utilised suboptimally-matched controls for each endpoint. The relative risk of stroke in irradiated patients ranged from 1.12 in patients with breast cancer to 5.6 in patients treated for head and neck cancer. The prevalence of CAS was increased by 16–55%, with the more modest increase seen in a study using matched controls. CIMT was increased in irradiated carotid arteries by 18–40%. Only two matched-control studies demonstrated a significant increase in CIMT of 36% and 22% (p = 0.003 and <0.001, respectively). Early prospective data demonstrated a significant increase in CIMT in irradiated arteries at 1 and 2 years after RT (p < 0.001 and <0.01, respectively). Conclusions: The incidence of stroke was significantly increased in patients receiving RT to the neck. There was a consistent difference in CAS and CIMT between irradiated and unirradiated carotid arteries. Future studies should optimise control groups

  6. Radiation-induced phase transition of paraffins

    When irradiated by the 500 kV electron at a dose of about 1.5 x 10-3 C/cm2, normal paraffins exhibit a solid-solid phase transition; a transition from a triclinic form to an orthorhombic one in n-C22H46 and n-C24H50 and from a monoclinic form to an orthorhombic one in n-C28H58, n-C36H74 and n-C44H90. The transition to a phase with high energy (orthorhombic phase) accommodates the radiation-induced stresses. The excess strain energy produced by cross-links in crystals is assumed to be equal to the enthalpy change of the phase transition, and the number of cross-links required to induce the phase transition is estimated at one per volume of about ten molecular chains. To compare with irradiated crystals, mixed crystals are prepared from solutions of binary mixtures of n-C23H48 and n-C24H50 and of n-C24H50 and n-C25H52. When the content of impurities (n-C23H48 or n-C25H52) reaches 10% in molar fraction, the crystal form of mixed crystals changes from the stable triclinic one to the unstable orthorhombic one. Thus, the number of lattice imperfections of mixed lattice is also estimated at one per volume of ten molecules. It is concluded from the above two estimations that the phase transition occurs when the content of lattice imperfections reaches the value of one per ten molecular chains and the value does not depend on the type of imperfections in these paraffins. (author)

  7. Delayed Radiation-Induced Vasculitic Leukoencephalopathy

    Purpose: Recently, single-fraction, high-dosed focused radiation therapy such as that administered by Gamma Knife radiosurgery has been used increasingly for the treatment of metastatic brain cancer. Radiation therapy to the brain can cause delayed leukoencephalopathy, which carries its own significant morbidity and mortality. While radiosurgery-induced leukoencephalopathy is known to be clinically different from that following fractionated radiation, pathological differences are not well characterized. In this study, we aimed to integrate novel radiographic and histopathologic observations to gain a conceptual understanding of radiosurgery-induced leukoencephalopathy. Methods and Materials: We examined resected tissues of 10 patients treated at Yale New Haven Hospital between January 1, 2009, and June 30, 2010, for brain metastases that had been previously treated with Gamma Knife radiosurgery, who subsequently required surgical management of a symptomatic regrowing lesion. None of the patients showed pathological evidence of tumor recurrence. Clinical and magnetic resonance imaging data for each of the 10 patients were then studied retrospectively. Results: We provide evidence to show that radiosurgery-induced leukoencephalopathy may present as an advancing process that extends beyond the original high-dose radiation field. Neuropathologic examination of the resected tissue revealed traditionally known leukoencephalopathic changes including demyelination, coagulation necrosis, and vascular sclerosis. Unexpectedly, small and medium-sized vessels revealed transmural T-cell infiltration indicative of active vasculitis. Conclusions: We propose that the presence of a vasculitic component in association with radiation-induced leukoencephalopathy may facilitate the progressive nature of the condition. It may also explain the resemblance of delayed leukoencephalopathy with recurring tumor on virtually all imaging modalities used for posttreatment follow-up.

  8. Radiation induced promising mutants in Cowpea

    Cowpea (Vigna unguiculata L. Walp.) is an important legume crop of the tropics and subtropics of Asia, Africa and America. Breeding objectives in recent years have been to combine high yields with upright growth habit, bushy dwarf determinate plant type, early maturity and large seed size in addition to resistance to biotic and abiotic stresses. With a view to achieving these objectives and creating additional - variability, the seeds of an elite variety V-130 were irradiated with 200 Gy of gamma rays, and a number of morphological mutants were isolated. The mutants with desirable characters like erect growth habit, dwarf, large seed size, and high pod number were isolated in the M2 generation and studied further in subsequent generations for their yield potential and other characteristics. The dwarf plant mutant TCM 77-4, characterised by reduced plant height, bushy growth, large seed size and absence of tendril bred true when grown in rabi seasons, but behaved like parent in respect of growth habit in kharif season. It was far superior to the parent in respect of seed size in all the seasons. The mutant is envisaged to be the most suitable for rice fallows. Among the several promising mutants with large seed size, the mutant TCM 13-5 showed a test weight of 16.8 g against 8.8 g of the parent. A mutant with large pod number designated as TCM 121-8 showed promise with its very high yield, when grown in summer albeit with delayed maturity. Several mutants with maturity similar to that of the parent have shown higher seed yield. The variability generated through the radiation- induced mutation is being utilised for creating novel high yielding early maturing varieties of cowpea. (author)

  9. A case of radiation induced cancer

    Ozawa, Kazuyoshi; Tsuchikawa, Kohzo; Sato, Akira; Kato, Joji (Nippon Dental Univ., Niigata (Japan). School of Dentistry at Niigata)

    1994-06-01

    A case of carcinoma on the right buccal mucosa is presented. The case was suspected to have been induced by irradiation therapy for a carcinoma on the left buccal mucosa. An external radiotherapy, 6-MeV Linac, had been done for the carcinoma on the left buccal mucosa in a 55-year-old female, with single lateral direction from the left to the right in 1977. In 1985, a papillary lesion on the right buccal mucosa was detected, and histological examination revealed a papilloma without atypism. In 1991, as an ulcer on the right upper buccal fold as well as three papillary lesions in the central portion of the right buccal mucosa were found, the patient was referred to our clinic. Microscopical findings were consistent with the early invasive carcinomas. A surgical excision of these whole lesions and skin graft were completed. The criteria of this case for the suspicion of radiation-induced carcinoma were as follows. There was a long latent period of 14 years. The previous dose of irradiation, 60 Gy, was sufficient. The right buccal mucosa was involved in the radiation field. A severe scar on the left cheek resulted from the previous irradiation. Anatomically, there is no evidence of the secondary carcinoma on the right buccal mucosa with the primary carcinoma on the left buccal mucosa. No evidence for recurrence of the tumors on both sides of buccal mucosa has been detected so far. Further observations will be necessary to detect other tumors in the irradiated field later on. (author).

  10. Rosiglitazone attenuates pulmonary fibrosis and radiation-induced intestinal damage

    Mangoni, M.; Gerini, C.; Sottili, M.; Cassani, S.; Stefania, G.; Biti, G. [Radiotherapy Unit, Clinical Physiopathology Department, University of Florence, Firenze (Italy); Castiglione, F. [Department of Human Pathology and Oncology, University of Florence, Firenze (Italy); Vanzi, E.; Bottoncetti, A.; Pupi, A. [Nuclear Medicine Unit, Clinical Physiopathology Department, University of Florence, Firenze (Italy)

    2011-10-15

    Full text of publication follows: Purpose.-The aim of the study was to evaluate radioprotective effect of rosiglitazone (RGZ) on a murine model of late pulmonary damage and of acute intestinal damage. Methods.- Lung fibrosis: C57 mice were treated with the radiomimetic agent bleomycin, with or without rosiglitazone (5 mg/kg/day). To obtain an independent qualitative and quantitative measure for lung fibrosis we used high resolution CT, performed twice a week during the entire observation period. Hounsfield Units (HU) of section slides from the upper and lower lung region were determined. On day 31 lungs were collected for histological analysis. Acute intestinal damage: mice underwent 12 Gy total body irradiation with or without rosiglitazone. Mice were sacrificed 24 or 72 h after total body irradiation and ileum and colon were collected. Results.- Lung fibrosis: after bleomycin treatment, mice showed typical CT features of lung fibrosis, including irregular septal thickening and patchy peripheral reticular abnormalities. Accordingly, HU lung density was dramatically increased. Rosiglitazone markedly attenuated the radiological signs of fibrosis and strongly inhibited HU lung density increase (60% inhibition at the end of the observation period). Histological analysis revealed that in bleomycin-treated mice, fibrosis involved 50-55% of pulmonary parenchyma and caused an alteration of the alveolar structures in 10% of parenchyma, while in rosiglitazone-treated mice, fibrosis involved only 20-25% of pulmonary parenchyma, without alterations of the alveolar structures. Acute intestinal damage: 24 h after 12 Gy of total body irradiation intestinal mucosa showed villi shortening, mucosal thickness and crypt necrotic changes. Rosiglitazone showed a histological improvement of tissue structure, with villi and crypts normalization and oedema reduction. Conclusion.- These results demonstrate that rosiglitazone displays a protective effect on pulmonary fibrosis and radiation-induced

  11. Rosiglitazone attenuates pulmonary fibrosis and radiation-induced intestinal damage

    Full text of publication follows: Purpose.-The aim of the study was to evaluate radioprotective effect of rosiglitazone (RGZ) on a murine model of late pulmonary damage and of acute intestinal damage. Methods.- Lung fibrosis: C57 mice were treated with the radiomimetic agent bleomycin, with or without rosiglitazone (5 mg/kg/day). To obtain an independent qualitative and quantitative measure for lung fibrosis we used high resolution CT, performed twice a week during the entire observation period. Hounsfield Units (HU) of section slides from the upper and lower lung region were determined. On day 31 lungs were collected for histological analysis. Acute intestinal damage: mice underwent 12 Gy total body irradiation with or without rosiglitazone. Mice were sacrificed 24 or 72 h after total body irradiation and ileum and colon were collected. Results.- Lung fibrosis: after bleomycin treatment, mice showed typical CT features of lung fibrosis, including irregular septal thickening and patchy peripheral reticular abnormalities. Accordingly, HU lung density was dramatically increased. Rosiglitazone markedly attenuated the radiological signs of fibrosis and strongly inhibited HU lung density increase (60% inhibition at the end of the observation period). Histological analysis revealed that in bleomycin-treated mice, fibrosis involved 50-55% of pulmonary parenchyma and caused an alteration of the alveolar structures in 10% of parenchyma, while in rosiglitazone-treated mice, fibrosis involved only 20-25% of pulmonary parenchyma, without alterations of the alveolar structures. Acute intestinal damage: 24 h after 12 Gy of total body irradiation intestinal mucosa showed villi shortening, mucosal thickness and crypt necrotic changes. Rosiglitazone showed a histological improvement of tissue structure, with villi and crypts normalization and oedema reduction. Conclusion.- These results demonstrate that rosiglitazone displays a protective effect on pulmonary fibrosis and radiation-induced

  12. Indomethacin attenuation of radiation-induced hyperthermia does not modify radiation-induced motor hypoactivity

    Ferguson, J.L.; Kandasamy, S.B.; Harris, A.H.; Davis, H.D.; Landauer, M.R. [Armed Forces Radiobiology Research Inst., Bethesda, MD (United States)

    1996-09-01

    Exposure of rats to 5-10 Gy of ionizing radiation produces hyperthermia and reduces motor activity. Previous studies suggested that radiation-induced hyperthermia results from a relatively direct action on the brain and is mediated by prostaglandins. To test the hypothesis that hypoactivity may be, in part, a thermoregulatory response to this elevation in body temperature, adult male rats were given indomethacin (0.0, 0.5, 1.0, and 3.0 mg/kg, intraperitoneally), a blocker of prostaglandin synthesis, and were either irradiated (LINAC 18.6 MeV (nominal) high-energy electrons, 10 Gy at 10 Gy/min, 2.8 {mu}sec pulses at 2 Hz) or sham-irradiated. The locomotor activity of all rats was then measured for 30 min in a photocell monitor for distance traveled and number of vertical movements. Rectal temperatures of irradiated rats administered vehicle only were elevated by 0.9{+-}0.2degC at the beginning and the end of the activity session. Although indomethacin, at the two higher doses tested, attenuated the hyperthermia in irradiated rats by 52-75%, it did not attenuate radiation-induced reductions in motor activity. These results indicate that motor hypoactivity after exposure to 10 Gy of high-energy electrons is not due to elevated body temperature or to the increased synthesis of prostaglandins. (author)

  13. Characterization of a Novel Radiation-Induced Sarcoma Cell Line

    Lang, J.; Zhu, W.Z.; Nokes, B.; Sheth, S.G.; Novák, Petr; Fuchs, L.; Watts, G.; Futscher, B. W.; Mineyev, N.; Ring, A.

    2015-01-01

    Roč. 111, č. 6 (2015), s. 669-682. ISSN 0022-4790 Institutional support: RVO:60077344 Keywords : Sarcoma * radiation-induced * breast * cancer Subject RIV: FD - Oncology ; Hematology Impact factor: 3.244, year: 2014

  14. Clarithromycin Attenuates Radiation-Induced Lung Injury in Mice

    Lee, Seung Jun; Yi, Chin-ok; Heo, Rok Won; Song, Dae Hyun; Cho, Yu Ji; Jeong, Yi Yeong; Kang, Ki Mun; Roh, Gu Seob; Lee, Jong Deog

    2015-01-01

    Radiation-induced lung injury (RILI) is a common and unavoidable complication of thoracic radiotherapy. The current study was conducted to evaluate the ability of clarithromycin (CLA) to prevent radiation-induced pneumonitis, oxidative stress, and lung fibrosis in an animal model. C57BL/6J mice were assigned to control, irradiation only, irradiation plus CLA, and CLA only groups. Test mice received single thoracic exposures to radiation and/or oral CLA (100 mg/kg/day). Histopathologic finding...

  15. Physical mechanisms of radiation induced creep in metals

    Analysis of available experimental data has been conducted. It enables to correlate reliably the character of evolution of dislocation structure of irradiated materials with different stages of radiation induced creep. This provides reliable basis for the general conclusions concerning the character of some parametric dependences of deformation rate of these materials. Analysis of different modern theoretical models enables to evaluate regions of their applicability and their relative significance for radiation induced creep description. 20 refs.; 2 figs.; 1 tab

  16. Radiation Induced Degradation of Galactomannan Polysaccharides

    Galactomannans are neutral polysaccharides that occur in substantial amounts in the endosperm of the seeds of some leguminous plants. Structurally they consist of a β(1-4)-D-mannose backbone to which galactose units are attached α(1-6). Among various galactomannans known, guar gum (GG), tara gum (TG) and locust bean gum (LBG) are the most widely used in applications in, for example, the food, pharmaceutical, and chemical industries as thickening agents or stabilizers due mainly to the high viscosity they impart at low concentrations. In many industrial applications, the use of low molecular weight polysaccharides is essential. For example, guar solutions, which are used as hydraulic fracturing fluids in oil and gas recovery, need to be degraded to facilitate the outflow of oil. In addition, to understand the solution properties of guar as well as other water-soluble biopolymers, it is often necessary to degrade the native polymer to prepare samples with various molecular weights (MW. Degradation of polysaccharides has been widely studied. Though acid and enzymatic hydrolysis are most common, other methods such as thermal, γ-irradiation, extrusion, ultrasonication and free radical degradation are also reported. In this study, radiation induced degradation of galactomannan polysaccharides has been investigated. GG, TG and LBG samples were irradiated with gamma rays in air at ambient temperature in the solid state at low dose rate. The change in their molecular weights was determined by SEC analysis and the change in their viscosity values as a function of temperature and irradiation dose was determined. Chain scission yields, G(S), and degradation rates were calculated. As a result of irradiation the molecular weight and viscosity of all galactomannans sharply decreased up to 50 kGy, no significant change was observed beyond this dose value. We observed that mannose-to-galactose ratio is an important factor controlling the G(S) and degradation rate of

  17. Radiation induced effects in carbon materials

    Full text: The level of safe exploiting nuclear reactor depends on radiation-induced changes of the neutron-absorbing material shape. The dimensional effects in carbon materials including those containing boron carbides B4C, irradiated in the water-water cooled reactor of the INP AS RUz operating at the power of 10 MW were studied in the temperature interval of 300-1500 K up to the integral fluence of 4·1021 neutrons per cm2. Two methods of dimensional control were used: dilatometry (change of linear dimensions and calculation of the volume change) and X-ray diffraction analysis (determination of the lattice parameters and the elementary unit volume). In all samples of low-ash and pyrolytic graphite (oriented parallel and normal to the pressing axis), irradiated up to the fluences above 1021 n/cm2 in the temperature range of 700-1100 K the shrinkage of linear dimensions was found from 6 to 8 %. While there occurred the primary swelling of graphite in the temperature interval of 300-700 K. The secondary swelling began at the fluence of 4·1021 cm-2 and 1100 K. Basing on these data, the neutron-absorbing graphite rods, containing B4C particles, were tested under the analogous irradiation conditions. The comparison of the rates of B4C swelling and graphite matrix shrinkage showed, that unfortunately, there was not gained the complete compensation of the swelling at the expense of shrinkage. The samples of fiber graphite, which were studied under the same conditions as the above mentioned, turned out stable in dimensions - changes in linear dimensions did not exceed 2 %. The X-diffraction study of ultra disperse amorphous carbon film irradiated in the water reactor discovered the formation of a denser carbon phase. The position of the observed structure reflection with d/n = 7.5 A did not correspond to the peaks of stable single phases of fullerenes C60 and C70. Perhaps, the irradiation creates a mixture of these phases in the amorphous matrix

  18. Differentiation between glioma recurrence and radiation-induced brain injuries using perfusion-weighted MR imaging

    Objective: To evaluate the feasibility of perfusion weighted imaging (PWI) in the differentiation of recurrent glioma and radiation-induced brain injuries. Methods: Fifteen patients with previously resected and irradiated glioma, presenting newly developed abnormal enhancement, were included in the study. The final diagnosis was determined either histologically or clinicoradiologically. PWI was obtained with a gradient echo echo-planar-imaging (GRE-EPI) sequence. The normalized rCBV ratio [CBV (abnormal enhancement)/CBV (contralateral tissue)], rCBF ratio [CBF (abnormal enhancement)/CBF (contralateral tissue)] and rMTT ratio [(MTT abnormal enhancement)/MTT (contralateral tissue)] were calculated, respectively. The regions of interest (ROIs) consisting of 20-40 mm2 were placed in the abnormal enhanced areas on postcontrast T1-weighted images. Ten to fifteen ROIs measurements were performed in each lesion and the mean value was obtained. Mann-Whitney test was used to determine whether there was a difference in the rCBV/rCBF/MTT ratios between glioma recurrence and radiated injuries. Results: Nine of the 15 patients were proved recurrent glioma, 6 were proved radiation-induced brain injuries. The mean rCBV ratio [2.87 (0.70-4.91)] in glioma recurrence was markedly higher than that [0.70 (0.12-1.62)] in radiation injuries (Z=-2.55, P<0.05). The mean rCBF ratio [1.89 (0.64-3.96)] in glioma recurrence was markedly higher than that [0.56 (0.12-2.08)] in radiation injuries (Z=-2.08, P<0.05). The areas under rCBV and rCBF ROC curve were 0.893 and 0.821. If the rCBV ratio ≤ 0.77, the diagnosis sensitivity of radiation-induced brain injuries was 100.0%; If ≥ 2.44, the diagnosis specificity of recurrent glioma was 100.0%. Conclusion: PWI was an effective technique in distinguishing glioma recurrence from radiation injuries and rCBV and rCBF ratios were of great value in the differentiation. (authors)

  19. Clinical and dosimetric factors of radiation-induced esophageal injury: Radiation-induced esophageal toxicity

    Wen-Bo Qiao; Yan-Hui Zhao; Yan-Bin Zhao; Rui-Zhi Wang

    2005-01-01

    AIM: To analyze the clinical and dosimetric predictive factors for radiation-induced esophageal injury in patients with non-small-cell lung cancer (NSCLC) during threedimensional conformal radiotherapy (3D-CRT). METHODS: We retrospectively analyzed 208 consecutive patients (146 men and 62 women) with NSCLC treated with 3D-CRT. The median age of the patients was 64 years (range 35-87 years). The clinical and treatment parameters including gender, age, performance status, sequential chemotherapy, concurrent chemotherapy, presence of carinal or subcarinal lymph nodes, pretreatment weight loss, mean dose to the entire esophagus, maximal point dose to the esophagus, and percentage of volume of esophagus receiving >55 Gy were studied. Clinical and dosimetric factors for radiation-induced acute and late grade 3-5 esophageal injury were analyzed according to Radiation Therapy Oncology Group (RTOG) criteria.RESULTS: Twenty-five (12%) of the two hundred and eight patients developed acute or late grade 3-5 esophageal injury. Among them, nine patients had both acute and late grade 3-5 esophageal injury, two died of late esophageal perforation. Concurrent chemotherapy and maximal point dose to the esophagus ≥60 Gy were significantly associated with the risk of grade 3-5 esophageal injury. Fifty-four (26%) of the two hundred and eight patients received concurrent chemotherapy. Among them, 25 (46%) developed grade 3-5 esophageal injury (P = 0.0001<0.01). However, nograde 3-5 esophageal injury occurred in patients who received a maximal point dose to the esophagus <60 Gy (P= 0.0001<0.01).CONCLUSION: Concurrent chemotherapy and the maximal esophageal point dose ≥60 Gy are significantly associated with the risk of grade 3-5 esophageal injury in patients with NSCLC treated with 3D-CRT.

  20. Role of endothelium in radiation-induced normal tissue damages

    More than half of cancers are treated with radiation therapy alone or in combination with surgery and/or chemotherapy. The goal of radiation therapy is to deliver enough ionising radiation to destroy cancer cells without exceeding the level that the surrounding healthy cells can tolerate. Unfortunately, radiation-induced normal tissue injury is still a dose limiting factor in the treatment of cancer with radiotherapy. The knowledge of normal tissue radiobiology is needed to determine molecular mechanisms involved in normal tissue pathogenic pathways in order to identify therapeutic targets and develop strategies to prevent and /or reduce side effects of radiation therapy. The endothelium is known to play a critical role in radiation-induced injury. Our work shows that endothelial cells promote vascular smooth muscle cell proliferation, migration and fibro-genic phenotype after irradiation. Moreover, we demonstrate for the first time the importance of PAI-1 in radiation-induced normal tissue damage suggesting that PAI-1 may represent a molecular target to limit injury following radiotherapy. We describe a new role for the TGF-b/Smad pathway in the pathogenesis of radiation-induced damages. TGF-b/Smad pathway is involved in the fibro-genic phenotype of VSMC induced by irradiated EC as well as in the radiation-induced PAI-1 expression in endothelial cells. (author)

  1. Radiation-induced camptocormia and dropped head syndrome. Review and case report of radiation-induced movement disorders

    In recent years, camptocormia and dropped head syndrome (DHS) have gained attention as particular forms of movement disorders. Camptocormia presents with involuntary forward flexion of the thoracolumbar spine that typically increases during walking or standing and may severely impede walking ability. DHS is characterized by weakness of the neck extensors and a consecutive inability to extend the neck; in severe cases the head is fixed in a ''chin to chest position.'' Many diseases may underlie these conditions, and there have been some reports about radiation-induced camptocormia and DHS. A PubMed search with the keywords ''camptocormia,'' ''dropped head syndrome,'' ''radiation-induced myopathy,'' ''radiation-induced neuropathy,'' and ''radiation-induced movement disorder'' was carried out to better characterize radiation-induced movement disorders and the radiation techniques involved. In addition, the case of a patient developing camptocormia 23 years after radiation therapy of a non-Hodgkin's lymphoma of the abdomen is described. In total, nine case series of radiation-induced DHS (n = 45 patients) and - including our case - three case reports (n = 3 patients) about radiogenic camptocormia were retrieved. Most cases (40/45 patients) occurred less than 15 years after radiotherapy involving extended fields for Hodgkin's disease. The use of wide radiation fields including many spinal segments with paraspinal muscles may lead to radiation-induced movement disorders. If paraspinal muscles and the thoracolumbar spine are involved, the clinical presentation can be that of camptocormia. DHS may result if there is involvement of the cervical spine. To prevent these disorders, sparing of the spine and paraspinal muscles is desirable. (orig.)

  2. Radiation-induced brain disorders in patients with pituitary tumours

    Radiation-induced brain disorders (RIBD) are uncommon and they are grave sequelae of conventional radiotherapy. In the present report, we describe the clinical spectrum of RIBD in 11 patients who received post-surgery conventional megavoltage irradiation for residual pituitary tumours. Of these 11 patients (nine men, two women), seven had been treated for non-functioning pituitary tumours and four for somatotropinomas. At the time of irradiation the age of these patients ranged from 30 to 59 years (mean, 39.4 ± 8.3; median, 36) with a follow-up period of 696 months (mean, 18.3 ± 26.4; median, 11). The dose of radiation ranged from 45 to 90 Gy (mean, 51.3 ± 13.4; median, 45), which was given in 1530 fractions (mean, 18.6 ± 5.0; median, 15) with 2.8 ± 0.3 Gy (median, 3) per fraction. The biological effective dose calculated for late complications in these patients ranged from 78.7 to 180 Gy (mean, 99.1 ± 27.5; median, 90). The lag time between tumour irradiation and the onset of symptoms ranged from 6 to 168 months (mean, 46.3 ± 57.0; median, 57). The clinical spectrum of RIBD included new-onset visual abnormalities in five, cerebral radionecrosis in the form of altered sensorium in four, generalized seizures in four, cognitive dysfunction in five, dementia in three and motor deficits in two patients. Magnetic resonance imaging (MRI)/CT of the brain was suggestive of radionecrosis in eight, cerebral oedema in three, cerebral atrophy in two and second neoplasia in one patient. Associated hormone deficiencies at presentation were hypogonadism in eight, hypoadrenalism in six, hypothyroidism in four and diabetes insipidus in one patient. Autopsy in two patients showed primitive neuroectodermal tumour (PNET) and brainstem radionecrosis in one, and a cystic lesion in the left frontal lobe following radionecrosis in the other. We conclude that RIBD have distinctive but varying clinical and radiological presentations. Diabetes insipidus and PNET as a second neoplastic

  3. Radiation-Induced Cancer. Proceedings of a Symposium on Radiation-Induced Cancer

    The link between radiation and cancer was recognized soon after the discovery of X-rays and natural radioactivity. In the early years after the discovery of ionizing radiations some of the pioneering workers suffered severely from the damaging effects of radiation exposure. These incidents,- generally due to ignorance of the biological consequences of radiation exposure, were instrumental in starting investigations on the subject. Gradually precise information became available on the nature of radiation-induced damage and on the repair phenomena. This information has been advanced by recent progress in molecular biology, cellular biology, cytogenetics, biochemistry, virology, immunology and related disciplines. Contributions of these disciplines to radiation biology and cancer research has resulted in the use of radiation to solve various problems of human health including cancer. At the same time, with knowledge of the effects of radiations on cells and on various organisms including man, it has become possible to state the level of radiation dose that is not an apparent health hazard (i. e. the maximum permissible dose). This work has been vitally important in programs dealing with the occupational safety of personnel working with radiations. Although the present safety standards and devices are generally recognized as adequate, they must be re-evaluated from time to time in the light of the latest findings in radiobiology and other related disciplines. The Symposium on Radiation-Induced Cancer, organized by the International Atomic Energy Agency in collaboration with the World Health Organization, permitted discussion and evaluation of the present understanding of the nature of late biological effects of radiations including cancer, and development of protective as well as curative measures against cancer. Much attention was given to the comparative analysis of the effects of radiation, particularly at low dose levels, on man and experimental mammals. Emphasis

  4. Radiation-induced endometriosis in Macaca mulatta

    Female rhesus monkeys received whole-body doses of ionizing radiation in the form of single-energy protons, mixed-energy protons, X rays, and electrons. Endometriosis developed in 53% of the monkeys during a 17-year period after exposure. Incidence rates for endometriosis related to radiation type were: single-energy protons, 54%; mixed-energy protons, 73%; X rays, 71%; and electrons, 57%. The incidence of endometriosis in nonirradiated control monkeys was 26%. Monkeys exposed to single-energy protons, mixed-energy protons, and X rays developed endometriosis at a significantly higher rate than control monkeys (chi 2, P less than 0.05). Severity of endometriosis was staged as massive, moderate, and minimal. The incidence of these stages were 65, 16, and 19%, respectively. Observations of clinical disease included weight loss in 43% of the monkeys, anorexia in 35%, space-occupying masses detected by abdominal palpation in 55%, abnormal ovarian/uterine anatomy on rectal examination in 89%, and radiographic evidence of abdominal masses in 38%. Pathological lesions were endometrial cyst formation in 69% of the monkeys, adhesions of the colon in 66%, urinary bladder in 50%, ovaries in 86%, and ureters in 44%, focal nodules of endometrial tissue throughout the omentum in 59%, and metastasis in 9%. Clinical management of endometriosis consisted of debulking surgery and bilateral salpingo-oophorectomy combined in some cases with total abdominal hysterectomy. Postoperative survival rates at 1 and 5 years for monkeys recovering from surgery were 48 and 36%, respectively

  5. Control of radiation-induced diarrhea with cholestyramine

    Cholestyramine is a non-absorbable ion-exchange resin which specifically binds bile salts. We have treated seven patients with acute or chronic radiation-induced diarrhea that was refractory to the usual methods of control with cholestyramine. In each case, the diarrhea was controlled with cholestyramine. This observation supports previous experimental work with animals which indicated that bile salts contribute to the genesis of radiation-induced diarrhea. Cholestyramine is well-tolerated, but should not be administered with certain oral medications. The results of this small series are preliminary, but point the way toward a more extensive clinical trial to define the usefulness of cholestyramine in the treatment of refractory acute or chronic radiation-induced diarrhea

  6. Hedgehog signaling and radiation induced liver injury: a delicate balance.

    Kabarriti, Rafi; Guha, Chandan

    2014-07-01

    Radiation-induced liver disease (RILD) is a major limitation of radiation therapy (RT) for the treatment of liver cancer. Emerging data indicate that hedgehog (Hh) signaling plays a central role in liver fibrosis and regeneration after liver injury. Here, we review the potential role of Hh signaling in RILD and propose the temporary use of Hh inhibition during liver RT to radiosensitize HCC tumor cells and inhibit their progression, while blocking the initiation of the radiation-induced fibrotic response in the surrounding normal liver. PMID:26202634

  7. Mechanistic issues for modeling radiation-induced segregation

    Model calculations of radiation-induced chromium depletion and radiation-induced nickel enrichment at grain boundaries are compared to measured depletions and enrichments. The model is calibrated to fit chromium depletion in commercial purity 304 stainless steel irradiated in boiling water reactor (BWR) environments. Predicted chromium depletion profiles and the dose dependence of chromium concentration at grain boundaries are in accord with measured trends. Evaluation of chromium and nickel profiles in three neutron, and two ion, irradiation environments reveal significant inconsistencies between measurements and predictions

  8. Natural background as an indicator of radiation-induced cancer

    A review of the estimates for radiation-induced cancer rates is presented including the recent high estimates of 8 x 10-3 cancers/man rem. Also reviewed are the external background radiation and cancer incidence for the USA by state. A regression analysis of these data reveals a negative correlation between radiation dose and cancer rate, but only with a correlation coefficient of 0.39. However, the cancer induction rate of 8 x 10-3/man rem is shown to describe the observed data with a probability of 1 in 14,000. Thus such high estimates of radiation-induced cancer rate are highly improbable. (UK)

  9. Panretinal photocoagulation for radiation-induced ocular ischemia

    We present preliminary findings on the effectiveness of panretinal photocoagulation in preventing neovascular glaucoma in eyes with radiation-induced ocular ischemia. Our study group consisted of 20 patients who developed radiation-induced ocular ischemia following cobalt-60 plaque radiotherapy for a choroidal or ciliary body melanoma. Eleven of the 20 patients were treated by panretinal photocoagulation shortly after the diagnosis of ocular ischemia, but nine patients were left untreated. In this non-randomized study, the rate of development of neovascular glaucoma was significantly lower (p = 0.024) for the 11 photocoagulated patients than for the nine who were left untreated

  10. Chemoprevention of Radiation Induced Rat Mammary Neoplasms

    Huso, David L.

    1999-01-01

    microcancers, arresting preneoplastic lesions, or correcting abnormal environments which predispose to high risk of malignant transformation.

  11. Clinical effectiveness of Ancer 20 injection for prevention of radiation-induced oral mucositis

    Although radiotherapy is very useful for treatment of oral cancer, it can cause radiation-induced oral mucositis as a troublesome side effect. Ancer 20 injection is useful for enhancing macrophage function, and apart from its inductive effect on IL-3, it also enhances G-CSF production. Therefore, Ancer 20 injection might also prevent mucositis. This effect was tested by administering the drug to prevent oral mucositis during radiotherapy. Eleven patients (5 males and 6 females, aged 39 to 84 yr, mean 64.5 yr) with squamous cell carcinoma were examined. Radiation was applied externally with a linear accelerator up to a total dose of 20-70 Gy, mean 38.2 Gy. All patients received a small dose of cisplatin concomitantly. Ancer 20 injection 1 ml twice weekly was administered subcutaneously. There was almost no objective or subjective abnormality up to a dose of 30 Gy, and at doses higher than that, the symptoms were mild in comparison with general mucosal reactions. This showed that Ancer 20 injection is useful for prevention of radiation-induced oral mucositis during radiotherapy of oral cancer. (author)

  12. Radiation-induced cognitive dysfunction: An experimental model in the old rat

    To develop a model of radiation-induced behavioral dysfunction. A course of whole brain radiation therapy (30 Gy/10 fractions/12 days) was administered to 26 Wistar rats ages 16-27 months, while 26 control rats received sham irradiation. Sequential behavioral studies including one-way avoidance, two-way avoidance, and a standard operant conditioning method (press-lever avoidance) were undertaken. In addition, rats were studied in a water maze 7 months postradiation therapy. Prior to radiation therapy, both groups were similar. No difference was found 1 and 3 months postradiation therapy. At 6-7 months postradiation therapy, irradiated rats had a much lower percentage of avoidance than controls for one-way avoidance (23% vs. 55%, p ≤ 0.001) and two-way avoidance (18% vs. 40%, p ≤ 0.01). Seven months postradiation therapy the reaction time was increased (press-lever avoidance, 11.20 s vs. 8.43 s, p ≤ 0.05) and the percentage of correct response was lower (water maze, 53% vs. 82%) in irradiated rats compared with controls. Pathological examination did not demonstrate abnormalities of the irradiated brains at the light microscopic level. Behavioral dysfunction affecting mainly memory can be demonstrated following conventional radiation therapy in old rats. This model can be used to study the pathogenesis of radiation-induced cognitive changes. 15 refs., 3 figs., 1 tab

  13. Radiation-induced cognitive dysfunction: an experimental model in the old rat

    Purpose: To develop a model of radiation-induced behavioral dysfunction. Methods and Materials: A course of whole brain radiation therapy (30 Gy/10 fractions/12 days) was administered to 26 Wistar rats ages 16-27 months, while 26 control rats received sham irradiation. Sequential behavioral studies including one-way avoidance, two-way avoidance, and a standard operant conditioning method (press-lever avoidance) were undertaken. In addition, rats were studied in a water maze 7 months postradiation therapy. Results: Prior to radiation therapy, both groups were similar. No difference was found 1 and 3 months postradiation therapy. At 6-7 months postradiation therapy, irradiated rats had a much lower percentage of avoidance than controls for one-way avoidance (23% vs. 55%, p ≤ 0.001) and two-way avoidance (18% vs. 40%, p ≤ 0.01). Seven months postradiation therapy the reaction time was increased (press-lever avoidance, 11.20 s vs. 8.43 s, p ≤ 0.05) and the percentage of correct response was lower (water maze, 53% vs. 82%) in irradiated rats compared with controls. Pathological examination did not demonstrate abnormalities of the irradiated brains at the light microscopic level. Conclusion: Behavioral dysfunction affecting mainly memory can be demonstrated following conventional radiation therapy in old rats. This model can be used to study the pathogenesis of radiation-induced cognitive changes

  14. Radiographic and CT features of radiation-induced organizing pneumonia syndrome after breast-conserving therapy

    The purpose of this study was to investigate radiographic and computed tomography features of radiation-induced organizing pneumonia syndrome after breast-conserving surgery. The appearances and distribution of lung parenchymal abnormalities were retrospectively analyzed on chest radiographs (n=12) and computed tomography scan images (n=10) of 12 women (range 37-78 years, mean 55.8 years) with radiation-induced organizing pneumonia syndrome after breast-conserving surgery. The principal radiographic feature was an airspace filling pattern in all patients that involved the middle and lower lung zones in 10 of the 12 patients. Multi-focal lesions manifesting airspace consolidation surrounded by ground-glass opacities were the predominant CT finding in all 10 of these patients. The main lesion was predominantly located in the lung periphery in nine patients and contiguously extended to the central portion of the lung in seven patients. Frequent ancillary findings were airway dilation within the consolidation and lobar volume loss in nine and eight patients, respectively. All had solitary (6/10) or multifocal (4/10) distant lung opacities, mostly consistent with the finding of ground-glass opacities (9/10). Migration of the lung disease was observed in ten patients on subsequent radiographs. The cardinal radiologic feature of this syndrome is airspace consolidation surrounded by ground-glass opacification with airway dilation and volume loss, involving primarily the irradiated, subpleural area, along with distant opacities. (author)

  15. A non-human primate model of radiation-induced cachexia

    Cui, Wanchang; Bennett, Alexander W.; Zhang, Pei; Barrow, Kory R.; Kearney, Sean R.; Hankey, Kim G.; Taylor-Howell, Cheryl; Gibbs, Allison M.; Smith, Cassandra P.; MacVittie, Thomas J.

    2016-01-01

    Cachexia, or muscle wasting, is a serious health threat to victims of radiological accidents or patients receiving radiotherapy. Here, we propose a non-human primate (NHP) radiation-induced cachexia model based on clinical and molecular pathology findings. NHP exposed to potentially lethal partial-body irradiation developed symptoms of cachexia such as body weight loss in a time- and dose-dependent manner. Severe body weight loss as high as 20–25% was observed which was refractory to nutritional intervention. Radiographic imaging indicated that cachectic NHP lost as much as 50% of skeletal muscle. Histological analysis of muscle tissues showed abnormalities such as presence of central nuclei, inflammation, fatty replacement of skeletal muscle, and muscle fiber degeneration. Biochemical parameters such as hemoglobin and albumin levels decreased after radiation exposure. Levels of FBXO32 (Atrogin-1), ActRIIB and myostatin were significantly changed in the irradiated cachectic NHP compared to the non-irradiated NHP. Our data suggest NHP that have been exposed to high dose radiation manifest cachexia-like symptoms in a time- and dose-dependent manner. This model provides a unique opportunity to study the mechanism of radiation-induced cachexia and will aid in efficacy studies of mitigators of this disease. PMID:27029502

  16. Radiation-Induced Growth Retardation and Microstructural and Metabolite Abnormalities in the Hippocampus

    Zawaski, Janice A.; Sahnoune, Iman

    2016-01-01

    Cranial radiotherapy (CRT) increases survival in pediatric brain-tumor patients but can cause deleterious effects. This study evaluates the acute and long-term impact of CRT delivered during childhood/adolescence on the brain and body using a rodent model. Rats received CRT, either 4 Gy fractions × 5 d (fractionated) or a cumulative dose of 20 Gy (single dose) at 28 d of age. Animals were euthanized 1 d, 5 d, or 3.5 mo after CRT. The 3.5 mo group was imaged prior to euthanasia. At 3.5 mo, we observed significant growth retardation in irradiated animals, versus controls, and the effects of single dose on brain and body weights were more severe than fractionated. Acutely single dose significantly reduced body weight but increased brain weight, whereas fractionation significantly reduced brain but not body weights, versus controls. CRT suppressed cell proliferation in the hippocampal subgranular zone acutely. Fractional anisotropy (FA) in the fimbria was significantly lower in the single dose versus controls. Hippocampal metabolite levels were significantly altered in the single dose animals, reflecting a heightened state of inflammation that was absent in the fractionated. Our findings indicate that despite the differences in severity between the doses they both demonstrated an effect on cell proliferation and growth retardation, important factors in pediatric CRT. PMID:27242931

  17. Prevention of radiation induced taste aversion in rats

    Diltiazem, a calcium channel blocker, and a cardiovascular therapeutic agent offers significant protection to mice against lethal dose of ionizing radiation. Considering the potential efficacy of diltiazem as a radioprotector for human use, it was deemed necessary to investigate its influence on radiation-induced behavioural changes like nausea, vomiting, learning, memory and performance. In the present studies, conditioned taste aversion (CTA) test based on consumption of saccharin solution, was used as a marker of behavioural changes. Significant CTA (97±2%) was observed in rats irradiated with 60Co gamma rays (absorbed dose 1 Gy). Administration of diltiazem at doses greater than 10 mg/kg, body wt, evoked CTA in a dose-dependent manner and that was found to be further aggravated on irradiation. At a lower dose of 5 mg/kg, body wt, diltiazem did not evoke CTA and protected against radiation induced aversion significantly (62±3%). The results suggest that diltiazem at concentrations lower than 10 mg/kg, body wt, in rats may be useful in preventing radiation induced behavioural changes. This observation could be of particular significance in clinical radiotherapy where radiation induced nausea and vomiting are of great concern. (author)

  18. Preparation of polymer microspheres by radiation-induced polymerization

    Cross-liking monomer, diethylene glycol dimethacrylate gives microspheres from organic solution by radiation-induced polymerization. /One of the remarkable result is that the number of the microspheres is not changing during the polymerization. Ethyl methacrylate, maleic anhydride, styrene and acrylamide are used as comonomers. These comonomers give the microspheres in the range of 0 to 0.4 as mol fractions. (author)

  19. Poor outcome in radiation-induced constrictive pericarditis

    Karram, T.; Rinkevitch, D.; Markiewicz, W. (Technion Medical School, Haifa (Israel))

    1993-01-15

    The purpose was to compare the outcome of patients with radiation-induced constrictive pericarditis versus patients with constiction due to another etiology. Twenty patients with constrictive pericarditis were seen during 1975-1986 at a single medical center. Six had radiation-induced constrictive pericarditis (Group A). The etiology was idiopathic in ten subjects and secondary to carcinomatous encasement, chronic renal failure, purulent infection and tuberculosis in one patient each (Group B, N = 14). Meang age was 53.4 [+-] 15.5 years. Extensive pericardiectomy was performed in 3/6 Group A and 13/14 Group B patients. All Group A patients died, 4 weeks - 11 years post-diagnosis (median = 10 months). Two Group A patients died suddenly, one died post-operatively of respiratory failure, another of pneumonia and two of recurrent carcinoma. Thirteen Group B patients are alive (median follow-up = 72 months). The only death in this group was due to metastatic cancer. The poor outcome with radiation-induced constriction is probably multi-factorial. Poor surgical outcome is to be expected in patients with evidence of recurrent tumor, high-dose irradiation, pulmonary fibrosis or associated radiation-induced myocardinal, valvular or coronary damage.

  20. Data acquisition system used in radiation induced electrical degradation experiments

    White, D.P. [Oak Ridge National Lab., TN (United States)

    1995-04-01

    Radiation induced electrical degradation (RIED) of ceramic materials has recently been reported and is the topic of much research at the present time. The object of this report is to describe the data acquisition system for an experiment designed to study RIED at the High Flux Beam Reactor (HFBR) at Brookhaven National Laboratory.

  1. Seven cases of radiation-induced cutaneous squamous cell carcinoma

    We report 7 cases of radiation-induced skin cancer. The diagnosis was based on the history of radiotherapy for benign skin diseases (5 cases) and of occupational exposures to medical doctors (2 cases). All cases were squamous cell carcinomas which arose from chronic radiodermatitis. The estimated latent period of these tumors ranged from 6 to 64 years, with an average of 29.9 years. After surgical treatments of the lesions, no local recurrences were observed in all cases. Benign skin diseases had sometimes been treated with low-energy radiation before the 1960s. Considering the estimated latent period, the peak time point of developing risk of radiation-induced skin cancer by such treatment has been already passed, however, the danger of it should not be ignored in future. In association with multiplicity of radiation usage, occupational exposure of radiation may develop the risk of occurrence of skin cancer in future. Therefore, we should recognize that radiation-induced skin cancer is not in the past. In the cases of chronic skin diseases showing warty keratotic growth, erosion and ulcer, we should include chronic radio-dermatitis in the differential diagnosis. It is necessary to recall all patients about the history of radiotherapy or radiation exposure. Rapid histopathological examination is mandatory because of the suspicion of radiation-induced skin cancer. (author)

  2. Use of probiotics for prevention of radiation-induced diarrhea

    P Delia; G Sansotta; V Donate; P Frosina; G Messina; C De Renzis; G Famularo

    2007-01-01

    AIM: To investigate the efficacy of a high-potency probiotic preparation on prevention of radiation-induced diarrhea in cancer patients.METHODS: This was a double-blind, placebo-controlled trial. Four hundred and ninety patients who underwent adjuvant postoperative radiation therapy after surgery for sigmoid, rectal, or cervical cancer were assigned to either the high-potency probiotic preparation VSL#3 (one sachet t.i.d.,) or placebo starting from the first day of radiation therapy. Efficacy endpoints were incidence and severity of radiation-induced diarrhea, daily number of bowel movements, and the time from the start of the study to the use of loperamide as rescue medication.RESULTS: More placebo patients had radiation-induced diarrhea than VSL#3 patients (124 of 239 patients, 51.8%, and 77 of 243 patients, 31.6%; P < 0.001) and more patients given placebo suffered grade 3 or 4 diarrhea compared with VSL#3 recipients (55.4% and 1.4%, P < 0.001). Daily bowel movements were 14.7 ± 6 and 5.1 ± 3 among placebo and VSL#3 recipients (P < 0.05), and the mean time to the use of loperamide was 86 ± 6 h for placebo patients and 122 ± 8 h for VSL#3 patients (P < 0.001).CONCLUSION: Probiotic lactic acid-producing bacteria are an easy, safe, and feasible approach to protect cancer patients against the risk of radiation-induced diarrhea.

  3. Report of board IV: Radiation damages and radiation induced diseases

    Board IV (radiation damage and radiation-induced diseases) worked on the effects of ionizing radiation on living organisms and studies the radiation damage it entailed. Investigations with cells or model systems serve to recognize certain causal relationships in an organism out of the diversity of reactions encountered. (orig./AK)

  4. Radiation-induced camptocormia and dropped head syndrome. Review and case report of radiation-induced movement disorders

    Seidel, Clemens; Kuhnt, Thomas; Kortmann, Rolf-Dieter; Hering, Kathrin [Leipzig University, Department of Radiotherapy and Radiation Oncology, Leipzig (Germany)

    2015-10-15

    In recent years, camptocormia and dropped head syndrome (DHS) have gained attention as particular forms of movement disorders. Camptocormia presents with involuntary forward flexion of the thoracolumbar spine that typically increases during walking or standing and may severely impede walking ability. DHS is characterized by weakness of the neck extensors and a consecutive inability to extend the neck; in severe cases the head is fixed in a ''chin to chest position.'' Many diseases may underlie these conditions, and there have been some reports about radiation-induced camptocormia and DHS. A PubMed search with the keywords ''camptocormia,'' ''dropped head syndrome,'' ''radiation-induced myopathy,'' ''radiation-induced neuropathy,'' and ''radiation-induced movement disorder'' was carried out to better characterize radiation-induced movement disorders and the radiation techniques involved. In addition, the case of a patient developing camptocormia 23 years after radiation therapy of a non-Hodgkin's lymphoma of the abdomen is described. In total, nine case series of radiation-induced DHS (n = 45 patients) and - including our case - three case reports (n = 3 patients) about radiogenic camptocormia were retrieved. Most cases (40/45 patients) occurred less than 15 years after radiotherapy involving extended fields for Hodgkin's disease. The use of wide radiation fields including many spinal segments with paraspinal muscles may lead to radiation-induced movement disorders. If paraspinal muscles and the thoracolumbar spine are involved, the clinical presentation can be that of camptocormia. DHS may result if there is involvement of the cervical spine. To prevent these disorders, sparing of the spine and paraspinal muscles is desirable. (orig.) [German] In den letzten Jahren haben Bewegungsstoerungen von Wirbelsaeule und paraspinaler Muskulatur in

  5. Unusual progression and subsequent improvement in cystic lung disease in a child with radiation-induced lung injury

    Wolf, Michael S. [Monroe Carell Jr. Children' s Hospital at Vanderbilt, Department of Pediatrics, Nashville, TN (United States); Chadha, Ashley D. [Vanderbilt University School of Medicine, Division of Pulmonary Medicine, Department of Pediatrics, Nashville, TN (United States); Carroll, Clinton M.; Borinstein, Scott C. [Vanderbilt University School of Medicine, Division of Hematology and Oncology, Department of Pediatrics, Nashville, TN (United States); Young, Lisa R. [Vanderbilt University School of Medicine, Division of Pulmonary Medicine, Department of Pediatrics, Nashville, TN (United States); Vanderbilt University School of Medicine, Division of Allergy, Pulmonary and Critical Care, Department of Medicine, Nashville, TN (United States); Vanderbilt University School of Medicine, Division of Pulmonary Medicine, Nashville, TN (United States)

    2015-07-15

    Radiation-induced lung disease is a known complication of therapeutic lung irradiation, but the features have not been well described in children. We report the clinical, radiologic and histologic features of interstitial lung disease (ILD) in a 4-year-old child who had previously received lung irradiation as part of successful treatment for metastatic Wilms tumor. Her radiologic abnormalities and clinical symptoms developed in an indolent manner. Clinical improvement gradually occurred with corticosteroid therapy. However, the observed radiologic progression from interstitial and reticulonodular opacities to diffuse cystic lung disease, with subsequent improvement, is striking and has not been previously described in children. (orig.)

  6. Unusual progression and subsequent improvement in cystic lung disease in a child with radiation-induced lung injury

    Radiation-induced lung disease is a known complication of therapeutic lung irradiation, but the features have not been well described in children. We report the clinical, radiologic and histologic features of interstitial lung disease (ILD) in a 4-year-old child who had previously received lung irradiation as part of successful treatment for metastatic Wilms tumor. Her radiologic abnormalities and clinical symptoms developed in an indolent manner. Clinical improvement gradually occurred with corticosteroid therapy. However, the observed radiologic progression from interstitial and reticulonodular opacities to diffuse cystic lung disease, with subsequent improvement, is striking and has not been previously described in children. (orig.)

  7. Effect of Epicatechin against Radiation-Induced Oral Mucositis: In Vitro and In Vivo Study

    Shin, Yoo Seob; Shin, Hyang Ae; Kang, Sung Un; Kim, Jang Hee; Oh, Young-Taek; Park, Keun Hyung; Kim, Chul-Ho

    2013-01-01

    Purpose Radiation-induced oral mucositis limits the delivery of high-dose radiation to head and neck cancer. This study investigated the effectiveness of epicatechin (EC), a component of green tea extracts, on radiation-induced oral mucositis in vitro and in vivo. Experimental Design The effect of EC on radiation-induced cytotoxicity was analyzed in the human keratinocyte line HaCaT. Radiation-induced apoptosis, change in mitochondrial membrane potential (MMP), reactive oxygen species (ROS) g...

  8. The progress in research on the mechanism, prevention and treatment of radiation-induced lung injury

    During radiotherapy of chest tumor,many patients often develop radiation-induced lung injury (including radiation induced interstitial pneumonia or pulmonary fibrosis), which significantly affects their quality of life. Therefore, it is very important to study the mechanism, prevention, and treatment of radiation-induced lung injury. Herein a review of recent research advances in radiation-induced lung injury is made, in order to provide theoretical basis for further research. (authors)

  9. Depleted uranium and radiation - induced lung cancer and leukaemia

    Reports of leukaemias and other cancers among servicemen who took part in the 1991 Gulf war or in the more recent operations in the Balkans are of continuing interest, as is the possibility, however slight, that depleted uranium (DU) is one of the causative factors. This commentary includes the results of a UK epidemiological study on the mortality of Gulf war veterans and , although not containing information on DU exposure, gives data on overall levels of mortality and therefore carries more weight than anecdotal reports. Also included are brief summaries on radiation-induced lung cancer in uranium workers as well as radiation-induced leukaemia in Japanese atomic bomb survivors and patients ankylosing spondylitis treated using x-rays. This commentary concludes with a critique of Iraqi cancer statistics as well as giving information on environmental contamination in Kosovo and the use of DU ammunition. (author)

  10. Action of liposomal superoxide dismutase on measurable radiation - induced fibroses

    Radiation-induced fibroses are a classical complication of radiotherapy. The effect of liposomal superoxide dismutase (Lipsod) on 45 radiation-induced fibroses of measurable volume and hardness in 34 patients was studied Over 3 weeks, 6 injections of Lipsod were given intramuscularly: 5 mg for 28 patients and 2 mg for 6 patients. On the average, the volume decreased by 32%. A marked or moderate softening was observed in 80% of the fibroses; it was accompanied by functional improvement in 75% of the patients (in cases of preexisting difficulties). The effectiveness was independent of the time lag between the Lipsod treatment and irradiation. The decreases noted in the volume and hardness of the fibroses remained stable during a follow up of 5-24 months. This systematic study shows the interest of Lipsod treatment of quasi-experimental fibroses where no other effective therapy exists

  11. Radiation induced graft copolymerization of acrylamide onto poly (3-hydroxybutyrate)

    The graft copolymer poly (3-hydroxybutyrate)-g- polyacrylamide [P (HB-g-AAm)] was synthesized by radiation induced graft copolymerization of acrylamide onto poly (3-hydroxybutyrate). The study was conducted by the simultaneous irradiation method. The structure of [P (HB-g-AAm)] was identified by Fourier Transform Infrared (FTIR) spectroscopy. Thermal behavior of the graft copolymer was also studied by Thermal Gravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC). From the results it was found that FTIR studies showed new signals (stretching -N-H) as strong evidence of grafting. The grafting degree was found to be 10 % and the thermodynamic parameter obtained from the DSC thermogram of plain PHB and the graft copolymer varied showing decrease in the material crystallinity and increase in the glass transition temperature. These results demonstrate that the radiation induced graft copolymerization reaction of acrylamide onto PHB was successively achieved. (Author)

  12. Caffeine Markedly Enhanced Radiation-Induced Bystander Effects

    JIANG Erkang; WU Lijun

    2009-01-01

    A bstract In this paper it is shown that incubation with 2 mM caffeine enhanced significantly the MN (micronucleus) formation in both the 1 cGy a-particle irradiated and non-irradiated by- stander regions. Moreover, caffeine treatment made the non-irradiated bystander cells more sensi- tive to damage signals. Treated by c-PTIO(2-(4-carboxy-phenyl)-4,4,5,5-tetramethyl-imidazoline- 1-oxyl-3-oxide), a nitric oxide (NO) scavenger, the MN frequencies were effectively inhibited, showing that nitric oxide might be very important in mediating the enhanced damage. These results indicated that caffeine enhanced the low dose a-particle radiation-induced damage in ir- radiated and non-irradiated bystander regions, and therefore it is important to investigate the relationship between the radiosensitizer and radiation-induced bystander effects (RIBE).

  13. A case of radiation-induced cancer of the hypopharynx

    Miyamoto, Kouji; Shimizu, Yukio; Yura, Jirou; Itoh, Yasufumi; Ikeda, Tsuneko [Matsunami General Hospital, Kasamatsu, Gifu (Japan); Outsubo, Toshio; Saitou, Hitoshi

    2001-06-01

    We report a case of radiation-induced cancer of the hypopharynx in a 65-year-old woman. The patient had received radiation treatment for Basedow's disease for several years starting at the age of 10 years. On June 26, 1993, she was examined at our hospital because of hoarseness and dysphagia. On July 22, right lobectomy was performed for suspected thyroid cancer. During this operation, endoscopy revealed hypopharyngeal cancer. Twenty-two days after surgery, total pharyngolaryngectomy and total esophagectomy were performed and a pharyngogastrostomy and a permanent tracheostomy were created. Histologic examination revealed moderately differentiated squamous cell cancer. This case was diagnosed as radiation-induced caner according to the diagnostic criteria of Sakai. (author)

  14. Treatment of Radiation Induced Biological Changes by Bone Marrow Transplantation

    Preventing the propagation of radiation induced oxidative damage has been a subject of considerable investigations. The ultimate goal of the present study is to use bone marrow cells to ameliorate or to treat the radiation sickness. Transplantation of bone marrow cell has shown promising results in the present experimental radiation treatment. In this report, suspension of bone marrow cells was injected into rats 12 h. after exposure to 4.5 Gy whole body gamma irradiation. Significant results were recorded on the successful control of the radiation induced disorders in a number of biochemical parameters including certain enzymatic and nonenzymatic antioxidants (superoxide dismutase and glutathione) and certain parameters related to kidney function including creatinine, urea as well as Atpase Activity in blood serum, urine and kidney tissue

  15. Radiation-induced hemorrhagic duodenitis associated with sorafenib treatment.

    Yanai, Shunichi; Nakamura, Shotaro; Ooho, Aritsune; Nakamura, Shigeo; Esaki, Motohiro; Azuma, Koichi; Kitazono, Takanari; Matsumoto, Takayuki

    2015-06-01

    Sorafenib, an oral inhibitor of multiple tyrosine kinase receptors, has been widely used as a standard medical treatment for advanced hepatocellular carcinoma (HCC). Here, we report a 66-year-old male patient who developed gastrointestinal bleeding due to radiation-induced hemorrhagic duodenitis associated with sorafenib treatment. We started oral administration of sorafenib because of the recurrence of HCC with lung metastases. The patient had been treated by radiotherapy for para-aortic lymph node metastases from HCC 4 months before the bleeding. Esophagogastroduodenoscopy (EGD) revealed edematous reddish mucosa with friability and telangiectasia in the second portion of the duodenum. Computed tomography and capsule endoscopy revealed that the hemorrhagic lesions were located in the distal duodenum. After discontinuation of sorafenib, the bleeding disappeared and a follow-up EGD confirmed improvement of duodenitis. Based on these findings, the diagnosis of radiation-induced hemorrhagic duodenitis associated with sorafenib was made. PMID:25832768

  16. Radiation-induced apoptosis in thymocytes: pH sensitization

    Thymocytes were used as a model system to study the effect of microenvironmental pH changes on the radiation-induced apoptosis. We found that the sensitivity of thymocytes toward radiation induced apoptosis is increased by increasing the pH of the incubation medium. The major sensitivity change occurs between pH 7 and 8. In a given cell suspension the results obtained were similar when the apoptosis evaluation was carried out either by counting the picnotic nuclei, or monitoring the fraction of apoptic nuclei by flow cytometry; both methods show a radiosensitization when the pH value of incubation media rises from 7 to 8. These results may be important when 'in vitro' experiments are performed with lymphoid cells, since changes in pH of the media may determine important changes in the results. (orig.)

  17. Repair of gamma radiation-induced damage : Micrococcus radiophilus

    The gamma radiation survival curve of M. radiophilus exhibits an extensive shoulder followed by exponential kill, indicating the efficiency of this bacterium for repairing gamma radiation induced damage. It differs morphologically, biochemically and genetically from M. radiodurans. Examination of DNA strand breaks using sucrose density gradient revealed the cell's ability to repair double and single strand breaks. Studies with alkaline gradients suggest that the fast repair of single strand scissions in M. radiophilus cellular DNA may be instantaneous. (author)

  18. A clinical examination of radiation-induced audibility complication

    Recent clinical reports indicate that patients receiving radiotherapy that includes the auditory system in the treatment volume are likely to develop a radiation induced hearing loss. The study of effect of radiotherapy for head and neck cancer on hearing was carried out on 9 patients who had pure tone recordings before, at completion and after radiotherapy. In this study, we did not find significant hearing loss but tend to occur transient hearing loss. (author)

  19. Radiation-induced apoptosis in microvascular endothelial cells.

    Langley, R. E.; Bump, E A; Quartuccio, S. G.; Medeiros, D.; Braunhut, S. J.

    1997-01-01

    The response of the microvasculature to ionizing radiation is thought to be an important factor in the overall response of both normal tissues and tumours. It has recently been reported that basic fibroblast growth factor (bFGF), a potent mitogen for endothelial cells, protects large vessel endothelial cells from radiation-induced apoptosis in vitro. Microvessel cells are phenotypically distinct from large vessel cells. We studied the apoptotic response of confluent monolayers of capillary en...

  20. A new view of radiation-induced cancer

    Shuryak, I.; Sachs, R K; Brenner, D J

    2010-01-01

    Biologically motivated mathematical models are important for understanding the mechanisms of radiation-induced carcinogenesis. Existing models fall into two categories: (1) short-term formalisms, which focus on the processes taking place during and shortly after irradiation (effects of dose, radiation quality, dose rate and fractionation), and (2) long-term formalisms, which track background cancer risks throughout the entire lifetime (effects of age at exposure and time since exposure) but m...

  1. Radiation-induced defect formation in chalcogenide glasses

    Shpotyuk, O.I.; Filipecki, J. [Physics Institute of Pedagogical University of Czestochowa, Al. Armii Krajowej 13/15, Czestochowa 42201 (Poland); Kozdras, A. [Physics Laboratory of Opole Technical University, 75 ul. Ozimska, Opole, PL-45370 (Poland); Kavetskyy, T.S. [Lviv Scientific Research Institute of Materials of Scientific Research Company ' Carat' , Stryjska Str. 202, Lviv, UA-79031 (Ukraine)

    2003-10-01

    The modified model of native and radiation-induced microvoid-type positron traps in vitreous chalcogenide semiconductors is developed to explain compositional features of positron annihilation lifetime measurements in stoichiometric As{sub 2}S{sub 3}-GeS{sub 2} and non-stoichiometric As{sub 2}S{sub 3}-Ge{sub 2}S{sub 3} chalcogenide glasses before and after {gamma}-irradiation.

  2. Radiation-induced myeloid leukemia in murine models

    Rivina, Leena; Davoren, Michael; Schiestl, Robert H.

    2014-01-01

    The use of radiation therapy is a cornerstone of modern cancer treatment. The number of patients that undergo radiation as a part of their therapy regimen is only increasing every year, but this does not come without cost. As this number increases, so too does the incidence of secondary, radiation-induced neoplasias, creating a need for therapeutic agents targeted specifically towards incidence reduction and treatment of these cancers. Development and efficacy testing of these agents requires...

  3. Establishment of murine model of radiation-induced oral mucositis

    Objective: To establish a murine model of radiation-induced oral mucositis. Methods: Left-sided buccal mucosa of 70 Sprague-Dawley rats were irradiated with X-rays (10 Gy/d), then six rats, selected randomly, were sacrificed at the 2nd, 4th, 6th, 8th, 14th, and 21st day after the irradiation, left-sided buccal mucosa were excised, corresponding irradiation dose for the selected rats were 20, 40, 60 and 80 Gy following radiation. The right buccal mucosa was excised and treated as its auto-controls tissue. Results: Erythema was observed in the left-sided buecal mucosa in rates irradiated with X-rays of 60 Gy; a single or more ulcers observed in rates irradiated with 80 Gy X-rays; a large area of ulcer was observed at 4th day after 80 Gy irradiation. The radiation-induced ulcer in buccal mucosa was essentially recovered after about 2 weeks following 80 Gy irradiation. Conclusion: This murine model of radiation-induced oral mucositis was useful and practical in experimental studies. (authors)

  4. Radiation induced enterocolitis in uterine cervical cancer after radiotherapy

    Objective: To approach the cause of radiation induced enterocolitis and its relationship with retropostion of the uterus in uterine cervical cancer after radiotherapy. Methods: Twenty-two patients with radiation induced enterocolitis, from 212 patients with uterine cervical cancer who had received radio-therapy during 2002-2005, were retrospectively analyzed. The incidence between patients with anteposition and patients with retroposition of uterus was compared. The distance between uterine central axis and the rectum of 15 patients with anteposition and 15 patients with retroposition of the uterus was measured, as well as the uterus retroversional flexion angle of the retropositioned uterus. Results: The incidence of radiation enterocolitis in patients with retroposition of uterus was obviously higher than that in patients with anteposition (χ2=21.10, P<0.01). The distance between point C and the rectum in patients with retroposition of uterus was shorter(t=7.33, P<0.05). The retroversional flexion angle of retropostitioned uterus were between 9-22 degree with a median angle of 17 degree. Conclusion: The incidence of radiation induced enterocolitis is higher in patients with retropostition of uterus after radiotherapy, because the distance between the uterine central axis and the rectum is shorter. The y axis and z axis often form an acute angle in the rectal direction during after-loading therapy, which would had led to an excessive dose to the rectum. (authors)

  5. Radiation-Induced Differentiation in Human Lung Fibroblast

    Park, Sa-Rah; Ahn, Ji-Yeon; Han, Young-Soo; Shim, Jie-Young; Yun, Yeon-Sook; Song, Jie-Young [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of)

    2007-10-15

    One of the most common tumors in many countries is lung cancer and patients with lung cancer may take radiotherapy. Although radiotherapy may have its own advantages, it can also induce serious problems such as acute radiation pneumonitis and pulmonary fibrosis. Pulmonary fibrosis is characterized by excessive production of {alpha}-SMA and accumulation of extracellular matrix (ECM) such as collagen and fibronectin. There has been a great amount of research about fibrosis but the exact mechanism causing the reaction is not elucidated especially in radiation-induced fibrosis. Until now it has been known that several factors such as transforming growth factor (TGF-{beta}), tumor necrosis factor (TNF), interleukin (IL)-1, IL-6, platelet-derived growth factor (PDGF) and fibroblast growth factor (FGF) are related to fibrosis. Among them TGF-{beta} with Smad signaling is known to be the main stream and other signaling molecules such as MAPK, ERK and JNK (3) also participates in the process. In addition to those above factors, it is thought that more diverse and complicate mechanisms may involve in the radiationinduced fibrosis. Therefore, to investigate the underlying mechanisms in radiation induced fibrosis, first of all, we confirmed whether radiation induces trans differentiation in human normal lung fibroblasts. Here, we suggest that not only TGF-{beta} but also radiation can induce trans differentiation in human lung fibroblast WI-38 and IMR-90.

  6. Radiation-induced products of peptides and their enzymatic digestibility

    Chemical characterization of radiation-induced products of peptides and proteins is essential for understanding the effect of ionizing radiation on peptides and proteins. Furthermore, peptides containing radiation-altered amino acid residues might not be completely digestible by proteolytic enzymes. In this work, small homopeptides of Ala, Phe and Met were chosen as model peptides. Lysozyme was used to investigate the effect of ionizing radiation on a small protein. All peptides and lysozyme were irradiated in diluted, oxygen free, N2O-saturated aqueous solutions, using a 60Co-γ-source. HPLC, capillary GC and GC-MS were applied to isolate and characterize the radiation-induced products. The enzymatic digestibility of the products was investigated using aminopeptidase M, leucine aminopeptidase, carboxypeptidase A and carboxypeptidase Y. It was found that irradiation of peptides examined in this work leads to racemization and alteration of amino acid residues and crosslinks between the peptide chains. In addition, it was established that exopeptidases act differently on radiation-induced dimers of peptides composed of aliphatic, aromatic and sulfur-containing amino acids

  7. Clarithromycin Attenuates Radiation-Induced Lung Injury in Mice.

    Seung Jun Lee

    Full Text Available Radiation-induced lung injury (RILI is a common and unavoidable complication of thoracic radiotherapy. The current study was conducted to evaluate the ability of clarithromycin (CLA to prevent radiation-induced pneumonitis, oxidative stress, and lung fibrosis in an animal model. C57BL/6J mice were assigned to control, irradiation only, irradiation plus CLA, and CLA only groups. Test mice received single thoracic exposures to radiation and/or oral CLA (100 mg/kg/day. Histopathologic findings and markers of inflammation, fibrosis, and oxidative stress were compared by group. On a microscopic level, CLA inhibited macrophage influx, alveolar fibrosis, parenchymal collapse, consolidation, and epithelial cell changes. The concentration of collagen in lung tissue was lower in irradiation plus CLA mice. Radiation-induced expression of tumor necrosis factor (TNF-α, TNF receptor 1, acetylated nuclear factor kappa B, cyclooxygenase 2, vascular cell adhesion molecule 1, and matrix metallopeptidase 9 were also attenuated by CLA. Expression levels of nuclear factor erythroid 2-related factor 2 and heme oxygenase 1, transforming growth factor-β1, connective tissue growth factor, and type I collagen in radiation-treated lungs were also attenuated by CLA. These findings indicate that CLA ameliorates the deleterious effects of thoracic irradiation in mice by reducing pulmonary inflammation, oxidative damage, and fibrosis.

  8. Clarithromycin Attenuates Radiation-Induced Lung Injury in Mice.

    Lee, Seung Jun; Yi, Chin-ok; Heo, Rok Won; Song, Dae Hyun; Cho, Yu Ji; Jeong, Yi Yeong; Kang, Ki Mun; Roh, Gu Seob; Lee, Jong Deog

    2015-01-01

    Radiation-induced lung injury (RILI) is a common and unavoidable complication of thoracic radiotherapy. The current study was conducted to evaluate the ability of clarithromycin (CLA) to prevent radiation-induced pneumonitis, oxidative stress, and lung fibrosis in an animal model. C57BL/6J mice were assigned to control, irradiation only, irradiation plus CLA, and CLA only groups. Test mice received single thoracic exposures to radiation and/or oral CLA (100 mg/kg/day). Histopathologic findings and markers of inflammation, fibrosis, and oxidative stress were compared by group. On a microscopic level, CLA inhibited macrophage influx, alveolar fibrosis, parenchymal collapse, consolidation, and epithelial cell changes. The concentration of collagen in lung tissue was lower in irradiation plus CLA mice. Radiation-induced expression of tumor necrosis factor (TNF)-α, TNF receptor 1, acetylated nuclear factor kappa B, cyclooxygenase 2, vascular cell adhesion molecule 1, and matrix metallopeptidase 9 were also attenuated by CLA. Expression levels of nuclear factor erythroid 2-related factor 2 and heme oxygenase 1, transforming growth factor-β1, connective tissue growth factor, and type I collagen in radiation-treated lungs were also attenuated by CLA. These findings indicate that CLA ameliorates the deleterious effects of thoracic irradiation in mice by reducing pulmonary inflammation, oxidative damage, and fibrosis. PMID:26114656

  9. Hypoxia expression in radiation-induced late rectal injury

    Tumor hypoxia and angiogenesis have been studied extensively. However, the relation between normal tissue injury and hypoxia is still unclear. In this study, we investigated the effect of hypoxia on radiation-induced late rectal injury in mice. The rectum of C57BL/6N mice was irradiated locally with a single dose of 25 Gy and the following experiments were performed including hematoxylin-eosin (H.E.) staining, azan staining, real-time polymerase chain reaction (PCR), immunohistochemistry and immunofluorescence. Radiation-induced fibrotic changes were observed from 14 days and reached the peak 30 days after irradiation. The expression of transforming growth factor β1 (TGF-β1), hypoxia-inducible factor-1α (HIF-1α), vascular endothelial growth factor (VEGF) and endothelial cell marker CD31 increased significantly with the formation of fibrosis induced by irradiation compared with unirradiated control. In addition, the maximum expression of TGF-β1, HIF-1α and VEGF was found at 14, 30 and 90 days after irradiation, respectively. The temporal changes of cytokines were consistent with the dynamic change of fibrosis. Our data suggests that late normal tissue injury involved various cytokines including hypoxia-induced angiogenic cytokines. These results may have important implications in the understanding of radiation-induced late normal tissue injury. (author)

  10. Rabbit model of radiation-induced lung injury

    Zhen-Zong Du; Hua Ren; Jian-Fei Song; Li-Fei Zhang; Feng Lin; Hai-Yong Wang

    2013-01-01

    Objective:To explore the feasibility of establishing an animal model of chronic radiation-induced lung injury.Methods:Twenty-eightNewZealand white rabbits were randomly divided into3 groups(the right lung irradiation group, the whole lung irradiation group and the control group).Animal model of radiation-induced lung injury was established by high-does radiotherapy in the irradiation groups, then all rabbits underwentCT and pathological examinations at1,2,4,8,12,16 weeks, respectively after radiation.Results:Within4 weeks of irradiation, some rabbits in the right lung irradiation group and whole lung irradiation group died. CT and pathological examinations all showed acute radiation pneumonitis.At8-12 weeks after irradiation,CT scanning showed ground glass samples signs, patchy shadows and fibrotic stripes. Pathological examination showed the fibrosis pulmonary alveolar wall thickened obviously. Conclusions:The clinical animal model of chronic radiation-induced lung injury which corresponds to practical conditions in clinic can be successfully established.

  11. Radiation induced structural changes in alpha-copper-zinc alloys

    During irradiation of alpha-copper-zinc alloys with high energy electrons and protons a decrease of the electrical resistivity due to an increase of the degree of short range order is observed through radiation enhanced diffusion followed by an increase of the electrical resistivity through the formation of radiation induced interstitial clusters. The initial formation rate of interstitial clusters increases about linearly with the displacement rate for electron and proton irradiation. The largest initial formation rate is found between 60 and 1300C becoming negligibly small above 1580C and decreases drastically below 600C. The dynamic steady state interstitial cluster concentration increases with decreasing irradiation temperature in the investigated temperature range between 158 and 400C. Above 1580C the formation rate of interstitial clusters is negligibly small. Thus the transition temperature for radiation induced interstitial cluster formation is 1580C, depending mainly on the migration activation energy of vacancies. The radiation induced interstitial clusters are precipitates in those alloys in which the diffusion rate of the undersized component atoms via an interstitialcy diffusion mechanism is larger than that of the other atoms

  12. Congenital Abnormalities

    ... blood flow to the fetus impair fetal growth. Alcohol consumption and certain drugs during pregnancy significantly increase the risk that a baby will be born with abnormalities (e.g. fetal alcohol spectrum disorders ). Eating raw or uncooked foods during pregnancy can also be dangerous to health of the ...

  13. The role of Fas in radiation induced apoptosis in vivo

    It has been recognized that interaction of the Fas: Fas ligand plays an important role in radiation-induced apoptosis. The purpose of this study was to investigate the role of Fas mutation in radiation-induced apoptosis in vivo. Mice with mutations in Fas, MRL/Mpj Faslpr, and its normal control, MRL/Mpj, were used in this study. Eight-week old male mice were given whole body radiation. After irradiation, the mice were killed and their spleens were collected at different time intervals. Tissue samples were stained with hematoxylin-eosin and the numbers of apoptotic cells were scored. Regulating molecules of apoptosis including p53, Bcl-2, Bax, Bcl-XL, and Bcl-Xs were also analyzed by Western blotting. At 25 Gy irradiation, the level of apoptosis reached the peak value at 8 hr after radiation and recovered to the normal value at 24 hr after radiation in MRL/Mpj mice. In contrast, the peak apoptosis level appeared at 4 hr after radiation in MRL/Mpj-Faslpr mice. At 8 hr after radiation, the levels of apoptosis in MRL/Mpj mice and MRL/Mpj-Faslpr mice were 52.3 ± 7.8% and 8.0 ± 8.6%, respectively (ρ L, and Bcl-Xs, increased in MRL/Mpj mice in response to radiation; p53 with a peak level of 3-fold at 8 h, Bcl-XL with a peak level of 3.3-fold at 12 h, and Bcl-Xs with a peak level of 3-fold at 12 h after 25 Gy radiation. Bcl-2 and Bax did not show significant change in MRL/Mpj mice. However in MRL/Mpj-Faslpr mice, the expression levels of p53, Bcl-2, Bax, Bcl-XL, and Bcl-Xs showed no significant change. The level of radiation-induced apoptosis was lower in Fas mutated mice, lpr, than in control mice. This seemed to be related to the lack of radiation-induced p53 activation in the lpr mice. This result suggests that Fas plays an important role in radiation-induced apoptosis in vivo

  14. The role of Fas in radiation induced apoptosis in vivo

    Kim, Sung Hee; Seong, Jin Sil; Seong, Je Kyung [Yonsei University Medical College, Seoul (Korea, Republic of)

    2002-09-15

    It has been recognized that interaction of the Fas: Fas ligand plays an important role in radiation-induced apoptosis. The purpose of this study was to investigate the role of Fas mutation in radiation-induced apoptosis in vivo. Mice with mutations in Fas, MRL/Mpj Fas{sup lpr}, and its normal control, MRL/Mpj, were used in this study. Eight-week old male mice were given whole body radiation. After irradiation, the mice were killed and their spleens were collected at different time intervals. Tissue samples were stained with hematoxylin-eosin and the numbers of apoptotic cells were scored. Regulating molecules of apoptosis including p53, Bcl-2, Bax, Bcl-X{sub L}, and Bcl-X{sub s} were also analyzed by Western blotting. At 25 Gy irradiation, the level of apoptosis reached the peak value at 8 hr after radiation and recovered to the normal value at 24 hr after radiation in MRL/Mpj mice. In contrast, the peak apoptosis level appeared at 4 hr after radiation in MRL/Mpj-Fas{sup lpr} mice. At 8 hr after radiation, the levels of apoptosis in MRL/Mpj mice and MRL/Mpj-Fas{sup lpr} mice were 52.3 {+-} 7.8% and 8.0 {+-} 8.6%, respectively ({rho} < 0.05). The expression of apoptosis regulating molecules, p53, Bcl-X{sub L}, and Bcl-X{sub s}, increased in MRL/Mpj mice in response to radiation; p53 with a peak level of 3-fold at 8 h, Bcl-X{sub L} with a peak level of 3.3-fold at 12 h, and Bcl-X{sub s} with a peak level of 3-fold at 12 h after 25 Gy radiation. Bcl-2 and Bax did not show significant change in MRL/Mpj mice. However in MRL/Mpj-Fas{sup lpr} mice, the expression levels of p53, Bcl-2, Bax, Bcl-X{sub L}, and Bcl-X{sub s} showed no significant change. The level of radiation-induced apoptosis was lower in Fas mutated mice, lpr, than in control mice. This seemed to be related to the lack of radiation-induced p53 activation in the lpr mice. This result suggests that Fas plays an important role in radiation-induced apoptosis in vivo.

  15. Suppression of the later stages of radiation-induced carcinogenesis by antioxidant dietary formulations.

    Kennedy, Ann R; Ware, Jeffrey H; Carlton, William; Davis, James G

    2011-07-01

    We have previously reported data from a long-term carcinogenesis study indicating that dietary antioxidant supplements can suppress radiation-induced malignant lymphoma and harderian gland tumors induced by space radiations (specifically, 1 GeV/n iron ions or protons) in CBA/J mice. Two different antioxidant dietary supplements were used in these studies: a supplement containing a mixture of antioxidant agents [l-selenomethionine (SeM), N-acetyl cysteine (NAC), ascorbic acid, co-enzyme Q10, α-lipoic acid and vitamin E succinate], termed the AOX supplement, and another supplement known as Bowman-Birk Inhibitor Concentrate (BBIC). In the present report, the results from the earlier analysis of the harderian gland data from the published long-term animal study have been combined with new data derived from the same long-term animal study. In the earlier analysis, harderian glands were removed from animals exhibiting abnormalities (e.g. visibly swollen areas) around the eyes at the time of euthanasia or death in the long-term animal study. Abnormalities around the eyes were usually due to the development of tumors in the harderian glands of these mice. The new data presented here focused on the histopathological results obtained from analyses of the harderian glands of mice that did not have visible abnormalities around the eyes at the time of necropsy in the long-term animal study. In this paper, the original published data and the new data have been combined to provide a more complete evaluation of the harderian glands from animals in the long-term carcinogenesis study, with all available harderian glands from the animals processed and prepared for histopathological evaluation. The results indicate that, although dietary antioxidant supplements suppressed harderian gland tumors in a statistically significant fashion when all glands were analyzed, the antioxidant diets were less effective at suppressing the incidence of all harderian gland tumors than they were at

  16. Alpha lipoic acid attenuates radiation-induced thyroid injury in rats.

    Jung Hwa Jung

    Full Text Available Exposure of the thyroid to radiation during radiotherapy of the head and neck is often unavoidable. The present study aimed to investigate the protective effect of α-lipoic acid (ALA on radiation-induced thyroid injury in rats. Rats were randomly assigned to four groups: healthy controls (CTL, irradiated (RT, received ALA before irradiation (ALA + RT, and received ALA only (ALA, 100 mg/kg, i.p.. ALA was treated at 24 h and 30 minutes prior to irradiation. The neck area including the thyroid gland was evenly irradiated with 2 Gy per minute (total dose of 18 Gy using a photon 6-MV linear accelerator. Greater numbers of abnormal and unusually small follicles in the irradiated thyroid tissues were observed compared to the controls and the ALA group on days 4 and 7 after irradiation. However, all pathologies were decreased by ALA pretreatment. The quantity of small follicles in the irradiated rats was greater on day 7 than day 4 after irradiation. However, in the ALA-treated irradiated rats, the numbers of small and medium follicles were significantly decreased to a similar degree as in the control and ALA-only groups. The PAS-positive density of the colloid in RT group was decreased significantly compared with all other groups and reversed by ALA pretreatment. The high activity index in the irradiated rats was lowered by ALA treatment. TGF-ß1 immunoreactivity was enhanced in irradiated rats and was more severe on the day 7 after radiation exposure than on day 4. Expression of TGF-ß1 was reduced in the thyroid that had undergone ALA pretreatment. Levels of serum pro-inflammatory cytokines (TNF-α, IL-1ß and IL-6 did not differ significantly between the all groups. This study provides that pretreatment with ALA decreased the severity of radiation-induced thyroid injury by reducing inflammation and fibrotic infiltration and lowering the activity index. Thus, ALA could be used to ameliorate radiation-induced thyroid injury.

  17. Efficacy of wheat germ oil in modulating radiation-induced heart damage in rats

    Wheat Germ oil is a natural unrefined vegetable oil. It is an excellent source of vitamin E, octacosanol, linoleic and linolenic essential fatty acids, which may be beneficial in neutralizing the free oxygen radicals. This study was designed to investigate the cardio-protective efficacy of wheat germ oil, on radiation-induced oxidative damage in rat's heart. Wheat germ oil was supplemented by gavage to rats at a dose of 81 mg/ kg body wt for 10 successive days pre- and 7 successive days post-exposure to 7 Gy (single dose) of whole body gamma irradiation. The dose of wheat germ oil is equivalent to daily human nutritional supplementation quantity. The results revealed that whole body ?-irradiation of rats produced significant alterations in blood cells picture. The erythrocyte, leucocyte, platelet counts and hemoglobin levels decreased after irradiation. Also, radiation-induced biochemical disorders manifested by significant elevation in xanthine oxidase activity (XO) and thiobarbituric acid reactive substances (TBARS) level, with decrease in reduced glutathione (GSH) content in heart tissues, indicating depression in the antioxidant status. Serum lipid profile as total cholesterol, high density lipoprotein-cholesterol (HDL-C), low density lipoprotein-cholesterol (LDL-C) and triglycerides levels (TG) were significantly higher than normal control rats. Radiation exposure produced a significant rise in the activities of serum markers for heart damage as creatine phosphokinase (CPK), aspartate aminotransferase (AST) and lactic dehydrogenase (LDH) indicating acute cardiac toxicity. Moreover, the obtained results revealed abnormal electrophoretic pattern of LDH isoenzymes in the 7th day after exposure to gamma rays. Three bands only appear on the agarose film comparing with 4 bands in normal control rats. The rats that received wheat germ oil supplement showed significantly less severe damage and remarkable improvement in all of the measured parameters when compared to

  18. Mapping of murine radiation-induced acute myeloid leukaemia susceptibility loci

    Studies on radiation-induced AML have shown characteristic phenotypic variation in susceptibility amongst inbred mouse strains, suggesting the involvement of genetic factors in determining the development of AML post-irradiation exposure. The main objective of the present study therefore was to identify and map markers in linkage disequilibrium with gene variants associated with influencing susceptibility to radiation induced AML in mice. Given Chr 2 abnormalities are characteristic of AML in mice, this feature was exploited in an effort to overcome the long latency for AML development. Analysis of Chr 2 aberrations at 24 and 48 h following irradiation established a positive correlation between Chr 2 radiosensitivity and radiation-AML susceptibility thus validating the choice of substitute assay. The analysis also resulted in the identification of a further trait, additional to Chr 2 radiosensitivity, termed overall chromosome radiosensitivity. Genetic mapping of Chr 2 radiosensitivity using public domain microsatellite database information resulted in the definition of cluster regions on 7 different chromosomes. Further genotyping reduced the candidate regions to 3 specific regions of interest. A test of allelic association could not ascertain a conclusive link between markers at these regions and the Chr 2 radiosensitivity/radiation-AML susceptibility phenotype. However, a region on Chr 4 around D4Mit221 appears to be most strongly associated. Similar studies identified three chromosomal regions of interest (on Chrs 4, 8 and 16) associated with overall chromosome radiosensitivity trait. An independent mapping strategy using F3 RCS confirmed the likely involvement of two of the candidate Chr 2 radiosensitivity regions identified by the inbred analysis including that on Chr 4 and also highlighted phenotypic heterogeneity amongst resistant RC strains, suggesting the influence of multiple alleles in specific phenotypes. RFLP analysis of candidate genes, localised on

  19. p53-dependent apoptosis suppresses radiation-induced teratogenesis

    About half of human conceptions are estimated not to be implanted in the uterus, resulting in unrecognizable spontaneous abortions. Experimental studies with mice have established that irradiation during the preimplantation period of the embryo induces a high incidence of prenatal deaths but virtually no malformations. This suggests that some mechanism is screening out the damaged fetuses. In order to elucidate the mechanisms of tissue repair of radiation-induced teratogenic injury, we compared the incidences of radiation-induced malformations and abortions in p53 null (p53-/-) and wild-type (p53+/+) mice. After X-irradiation with 2 Gy on day 9.5 of gestation, p53-/- mice showed a 70% incidence of anomalies and a 7% incidence of deaths, whereas p53+/+ mice had a 20% incidence of anomalies and a 60% incidence of deaths. Similar results were obtained after irradiation on day 3.5 of gestation. This reciprocal relationship of radiosensitivity to anomalies and to embryonic or fetal lethality supports the notion that the p53 gene protects embryos and fetuses against the teratogenic effects of radiation by eliminating cells that have been badly damaged. In fact, after X-irradiation, the frequency of dying cells by apoptosis was greatly increased in tissues of the p53+/+ fetuses but not at all in those of the p53-/- fetuses. Mammals are protected from radiation-induced injury by two mechanisms, p53-dependent apoptotic tissue repair in addition to well known DNA repair. Therefore, there are threshold doses below which there is no induction of teratogenic and carcinogenic effects after exposure to low-level radiation. (author)

  20. Radioprotective effects of melatonin on radiation-induced cataract

    One of the mechanisms proposed to explain lens opacification is the oxidation of crystallins, either by radiation or reactive oxygen species (ROS). It has been shown that melatonin has both an anti-peroxidative effect on several tissues and a scavenger effect on ROS. The purpose of this study was to determine the antioxidant role of melatonin (5 mg/kg/day) against radiation-induced cataract in the lens after total-cranium irradiation of rats with a single dose of 5 Gy. Sprague-Dawley rats were divided into four groups. Control group received neither melatonin nor irradiation. Irradiated rats (IR) and melatonin+irradiated rats (IR+Mel) groups were exposed to total cranium irradiation of 5 Gy in a single dose by using a cobalt-60 teletherapy unit. IR+Mel and melatonin (Mel) groups were administered 5 mg/kg melatonin daily by intraperitoneal injections during ten days. Chylack's cataract classification was used in this study. At the end of the 10th day, the rats were killed and their eyes were enucleated to measure the antioxidant enzymes i.e. the activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), and lipid peroxidation level (malondialdehyde (MDA)). Irradiation significantly increased the MDA level, as an end product of lipid peroxidation, and also significantly decreased SOD and GSH-Px activity, emphasizing the generation of increased oxidative stress. Rats injected with melatonin only did not cause cataract formation. Melatonin supplementation with irradiation significantly increased the activity of SOD and GSH-Px enzymes and significantly decreased the MDA level. Total cranium irradiation of 5 Gy in a single dose enhanced cataract formation, and melatonin supplementation protected the lenses from radiation-induced cataract formation. Our results suggest that supplementing cancer patients with adjuvant therapy of melatonin may reduce patients suffering from toxic therapeutic regimens such as chemotherapy and/or radiotherapy and may provide

  1. Construction of radiation - induced metastasis model in vivo

    Park, Jong Kuk; Jang, Su Jin; Kang, Sung Wook; Kim, Jae Sung; Hwang, Sang Gu; Kang, Joo Hyun [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of)

    2011-05-15

    In treatment of cancer, distant metastases are important limiting factor because an estimated 50% of all cancer patients will develop metastases, and the metastases are major causing of cancer treatment failure. Recently a few reports indicated {gamma}-radiation induced an increase of invasiveness of several cancer cells. In this study, we had tried to show the possibility that radiation could also induce metastasis in vivo system. To prove our hypothesis, we constructed primary tumor by using C6-TL transfectant cell line expressing HSV1-tk and firefly luciferase (fLuc), and then {gamma}-radiation was treated to xenografts locally. Treatment of {gamma}-radiation to primary C6-TL xenografts of mice reduced size of xenografts and elongated survival of mice than those of mock control mice. But we also show that {gamma}-radiation treatment was followed by the growth of dormant metastases in various organs including lung and intestine after 2-4 weeks of {gamma}-radiation treatment. When bioluminescence imaging indicated growth of tumor in organs in mice, we sacrificed the mice and repeat acquired bioluminescence imaging after repeatedly. These images presented tumor growth locations exactly in organs. Because metastatic tumor candidates have morphology of foci, biopsies were performed for histological analysis or PCR analysis to confirm metastases. In most foci, histological analysis indicated several features of typical cancer tissue and PCR analysis showed present of fLuc gene in metastases. Detection of fLuc gene in metastases indicated these foci were originated from primary C6-TL xenografts, and the results suggest that {gamma}-radiation could promote metastasis in vivo as well as in vitro system. Although we need to understand changes of intracellular signaling or physiological phenomena of the radiation-induced metastasis yet, these results also imply that {gamma}-radiation treatment only to cancer patients need to pay attention carefully, and development of new

  2. Use of radiation-induced polymers in cement slurries

    Water loss from cement slurries is reduced by incorporating within a cement slurry a polymer obtained as a product of radiation-induced polymerization of acrylamide and/or methacrylamide and acrylic acid, methacrylic acid, and/or alkali metal salts thereof. The polymerization is preferably carried out in 10-60 percent aqueous monomer solution with gamma radiation. The aqueous monomer solution preferably contains 25-99 percent acrylamide and 75-1 percent sodium acrylate. The polymer can be present in concentration of about 0.001 to about 3.0 weight percent, based on the aqueous phase of the slurry

  3. Use of radiation-induced polymers in cement slurries

    Water loss from cement slurries is reduced by incorporating within a cement slurry a polymer obtained as a product of radiation-induced polymerization of acrylamide and/or methacrylamide and acrylic acid, methacrylic acid, and/or alkali metal salts thereof. The polymerization is preferably carried out in 10 to 60 percent aqueous monomer solution with gamma radiation. The aqueous monomer solution preferably contains 25 to 99 percent acrylamide and 75 to 1 percent sodium acrylate. The polymer can be present in concentration of about 0.001 to about 3.0 weight percent, based on the aqueous phase of the slurry. (U.S.)

  4. 'Like new': plastic wastes regeneration by radiation induced grafting

    The reclaiming and the recycling of plastic wastes is made especially difficult when those wastes are a mixture of various plastics; this is due to the incompatibility of the polymers. The radiation induced grafting allows to overcome this incompatibility. Results are given which shows that, for various mixtures of reclaimed polyethylene, PVC and polystyrene, an improvement of the properties of the processed blends is obtained by grafting the mixtures of wastes by a suitable polymer; the obtained properties of those regenerated plastic blends are enough attractive from the technical point of view to open a market to those products with a reasonable economical value

  5. Sensitization of radiation-induced cell death by genistein

    Kim, Tae Rim; Kim, In Gyu [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2010-03-15

    A number of epidemiological studies as well as biological experiments, showed that genistein, one of the isoflavone, prevents prostate cancer occurrence. In this study, we showed that genistein inhibited the cell proliferation of human promyeoltic leukemia HL-60 cells and induced G2/M phase arrest. In addition, combination of genistein treatment and {gamma}-irradiation displayed synergistic effect in apoptotic cell death of HL-60 cells. This means that the repair of genistein-induced DNA damage was hindered by {gamma}-irradiation and thus cell death was increased. In conclusion, genistein is one of the important chemicals that sensitize radiation-induced cell death.

  6. Tissue culture regeneration and radiation induced mutagenesis in banana

    Radiation induced mutagenesis is an important tool for banana genetic improvement. At BARC, protocols for shoo-tip multiplication of commercial banana varieties have been developed and transferred to user agencies for commercial production. Excellent embryogenic cell suspensions were established in banana cvs. Rasthali and Rajeli, and were maintained at low temperatures for long-term storage. Normal plantlets were successfully regenerated from these cell suspensions. The cell suspensions and shoot-tip cultures were gamma-irradiated for mutagenesis. The mutagenized populations were field screened and a few interesting mutants have been isolated. The existence of genetic variation was confirmed using DNA markers. Further evaluation of these mutants is in progress. (author)

  7. Effect of electrodes in the radiation induced conductivity for polymers

    Samples of PET with 23 μm thickness were exposed to continuous X-rays and the radiation-induced conductivity (RIC) as a function of time were measured, using electrodes of evaporated aluminum and gold. The results showed that the use of higher atomic number metal electrodes increase the received dose rate by sample, without almost modifying the time evolution of the RIC or its dependence with the applied electric field intensity. It is also showed that this increase is caused by the electrode placed in the face of the sample where the radiation strikes, as well as by the one placed in the oposite face. (author)

  8. Chemical modification of polyurethanes by radiation-induced grafting

    Basic methods of radiation-induced modification of polyurethanes for biomedical applications and of their characterization are briefly described. The most important works found in literature on radiation grafting of polyurethanes are discussed. The radiation grafting of polyetherurethane films and tubings by the preswelling method using various monomers and their physico-chemical characterization are discussed in detail with respect to the antithrombogenic properties of the materials. Novel applications for radiation-modified polyurethanes as drug delivery systems or antiinfectious materials are briefly mentioned. 52 references

  9. RERF research agenda for studies of radiation-induced cancer

    In the last decade or so the numbers of cancers attributable to radiation among the Japanese A-bomb survivors have become large enough to permit quantitative estimates of risk and to encourage quantitative investigation of the many factors other than dose that appear to govern the appearance of radiation-induced cancer. The size and demographic complexity of the A-bomb survivor population are such that future studies should go far to provide the descriptive information on which our understanding of radiation carcinogenesis in man must ultimately depend. 60 references

  10. Quantitative analysis of radiation-induced disorder in spinel crystals

    Structural defects in the surface region of magnesium aluminate spinel (MgAl2O4) crystals irradiated with 450 MeV Xe ions were analyzed by using 4He backscattering in channeling geometry (RBS/C). Monte-Carlo simulations applied for the interpretation of channeling spectra permitted to determine the concentration of radiation-induced defects. They showed that the defect distributions are depth dependent, likely due to annihilation of defects at the surface of the crystals. The cross-section for the formation of defects by swift Xe ions, and consequently the diameter of an ion track, were estimated using single-impact-model calculations

  11. Transient radiation-induced absorption in laser materials

    Brannon, Paul J.

    1994-06-01

    Transient radiation-induced absorption losses in laser materials have been measured using a pulsed nuclear reactor. Reactor pulse widths of 70 to 90 microsecond(s) and absorbed doses of 1 to 7.5 krad have been used. Transmission recovery times and peak absorption coefficients are given. Materials tested include LiNbO3, GSGG, silica substrates, and filter glasses used in the laser cavity. The filter glasses are tested at discrete wavelengths in the range 440 - 750 nm. Lithium niobate, MgO-doped LiNbO3, GSGG, and the silica substrates are tested at 1061 nm.

  12. Transient radiation-induced absorption in laser materials

    Brannon, P.J.

    1994-12-31

    Transient radiation-induced absorption losses in laser materials have been measured using a pulsed nuclear reactor. Reactor pulse widths of 70 to 90 {mu}s and absorbed doses of 1 to 7.5 krad have been used. Transmission recovery times and peak absorption coefficients are given. Materials tested include LiNbO{sub 3}, GSGG, silica substrates, and filter glasses used in the laser cavity. The filter glasses are tested at discrete wavelengths in the range 440--750 nm. Lithium niobate , MgO doped LiNbO{sub 3}, GSGG, and the silica substrates are tested at 1061 nm.

  13. Does smoking protect against radiation-induced pneumonitis?

    The overall aim of the project reported here was to investigate the inflammatory reaction in the otherwise healthy human lung after ionizing irradiation. The tool used was the well accepted and now safe technique of bronchoalveolar lavage. The causality between smoking and the development of different forms of cancer, especially lung cancer, is well established. However, the possible effects of smoking on cancer treatment per se has been studied less. The authors observed, in addition to the expected inflammatory reactions in the lung parenchyma, that smoking during post-operative treatment of breast cancer seems to depress the grade of radiation-induced pneumonitis. (author)

  14. Inducible HSP70 Protects Radiation-Induced Salivary Gland Damage

    Irradiation (IR) delivered to the head and neck is a common treatment for malignancies. Salivary glands in the irradiation field are severely damaged, and consequently this resulted in marked salivary hypofunction. While the exact mechanism of salivary gland damage remains enigmatic, fluid secreting acinar cells are lost, and saliva output is dramatically reduced. Previously we have reported that inducible heat shock protein 70 (HSP70i) induced radioresistance in vitro. Moreover, HSP70i localized to salivary glands by gene transfer has great potential for the treatment of salivary gland. Herein, we investigated whether HSP70 can use as radio protective molecules for radiation-induced salivary gland damage in vivo

  15. Immobilization of yeast cells by radiation-induced polymerization

    Radiation-induced polymerization method was applied to the immobilization of yeast cells. The effects of irradiation, cooling and monomer, which are neccessary for polymerization, were recovered completely by subsequent aerobical incubation of yeast cells. The ethanol productive in immobilized yeast cells increased with the increase of aerobical incubation period. The growth of yeast cells in immobilized yeast cells was indicated. The maximum ethanol productivity in immobilized yeast cell system was around three times as much as that in free yeast cell system. (orig.)

  16. Radiation-induced cationic curing of vinyl ethers

    Recently there has been an increasing interest in nonacrylate radiation-curable coatings. Vinyl ethers are particularly reactive under cationic polymerization reaction conditions. The high efficiency of the photoacid initiators combined with the high reactivity of vinyl ether monomers makes this a potentially very useful system. This chapter discusses the preparation of vinyl ethers, introduces vinyl ether-functional monomers and oligomers, describes radiation-induced cationic polymerization of vinyl ethers, and discusses various coating systems. Throughout the chapter, an emphasis is placed on radiation-curable coating applications. 64 refs., 5 figs., 11 tabs

  17. Surgery for radiation-induced carcinoma of the hypopharynx

    Eighteen radiation-induced tumors of the hypopharynx examined during a 20-year period are described. These tumors represent slightly less than 5 per cent of all tumors of the hypopharynx examined during the same period. Most were due to irradiation for thyrotoxicosis, and the mean latent period was 35 years. Five patients were not treated, and 13 patients were treated, mainly by pharyngolaryngectomy followed by skin flap repair (deltopectoral or pectoralis major). Despite a fairly high complication rate, an adjusted five-year survival of 35 per cent was achieved

  18. Radiation-induced apoptosis in undifferentiated cells of the developing brain as a biological defense mechanism

    Undifferentiated neural (UN) cells of the developing mammalian brain are highly sensitive to the lethal effects of ionizing radiation. Nuclear and cytoplasmic condensation, transglutaminase activation, and internucleosomal DNA cleavage reveal radiation-induced cell death in the ventricular zone of the cerebral mantle and external granular layer of the cerebellum to be due to apoptosis. A statistically significant increase of cell mortality can be induced by 0.03 Gy X-irradiation, and the mortality increases linearly with increasing doses. It is not changed by split doses, probably because of the very slow repair of cellular damage and a lack of adaptive response. Although extensive apoptosis in the UN cell population results in microcephaly and mental retardation, it possesses the ability to recover from a considerable cell loss and to form the normal structure of the central nervous system. The number of cell deaths needed to induce tissue adnormalities in the adult murine brain rises in the range of 15-25% of the germinal cell population; with the threshold doses at about 0.3 Gy for cerebral anomalies and 1 Gy for cerebellar abnormalities. Threshold level is similarly suggested in prenatally exposed A-bomb survivors. High radiosensitivity of UN cells is assumed to be a manifestation of the ability of the cell to commit suicide when injured. Repeated replication of DNA and extensive gene expression are required in future proliferation and differentiation. Once an abnormality in DNA was induced and fixed in the UN cell, it would be greatly amplified and prove a danger in producing malformations and tumors. These cells would thus commit suicide for the benefit of the individual to eliminate their acquired genetic abnormalities rather than make DNA repair. UN cells in the developing brain are highly radiosensitive and readily involved in apoptosis. Paradoxically, however, this may be to protect individuals against teratogenesis and tumorigenesis. (J.P.N.)

  19. Radiation-induced apoptosis in undifferentiated cells of the developing brain as a biological defense mechanism

    Inouye, Minioru [Nagoya Univ. (Japan). Research Inst. of Environmental Medicine; Tamaru, Masao

    1994-12-31

    Undifferentiated neural (UN) cells of the developing mammalian brain are highly sensitive to the lethal effects of ionizing radiation. Nuclear and cytoplasmic condensation, transglutaminase activation, and internucleosomal DNA cleavage reveal radiation-induced cell death in the ventricular zone of the cerebral mantle and external granular layer of the cerebellum to be due to apoptosis. A statistically significant increase of cell mortality can be induced by 0.03 Gy X-irradiation, and the mortality increases linearly with increasing doses. It is not changed by split doses, probably because of the very slow repair of cellular damage and a lack of adaptive response. Although extensive apoptosis in the UN cell population results in microcephaly and mental retardation, it possesses the ability to recover from a considerable cell loss and to form the normal structure of the central nervous system. The number of cell deaths needed to induce tissue adnormalities in the adult murine brain rises in the range of 15-25% of the germinal cell population; with the threshold doses at about 0.3 Gy for cerebral anomalies and 1 Gy for cerebellar abnormalities. Threshold level is similarly suggested in prenatally exposed A-bomb survivors. High radiosensitivity of UN cells is assumed to be a manifestation of the ability of the cell to commit suicide when injured. Repeated replication of DNA and extensive gene expression are required in future proliferation and differentiation. Once an abnormality in DNA was induced and fixed in the UN cell, it would be greatly amplified and prove a danger in producing malformations and tumors. These cells would thus commit suicide for the benefit of the individual to eliminate their acquired genetic abnormalities rather than make DNA repair. UN cells in the developing brain are highly radiosensitive and readily involved in apoptosis. Paradoxically, however, this may be to protect individuals against teratogenesis and tumorigenesis. (J.P.N.).

  20. Ionizing radiation induced conductivity in Mylar (PET) and Kapton (Polyimide)

    The extensive results of measurements of the prompt and delayed radiation-induced conductivity of samples of PET and Kapton are presented. Experimental parameters, such as the effective energy of the radiation, the exposure rate, the total dose, the value of the applied electric field, the nature of the electrodes, and the ambiental conditions were changed within wide limits. We also report measurement of thermally stimulated currents for non-irradiated and for irradiated samples which allowed us to investigate the trap-structure of the materials. Measurements of photo-Compton currents with different electrode materials and sample thicknesses gave information about the relation between the nature of the electrodes and the amplitudes of the currents. Based on the generalized rate theory of radiation-induced conduction we developed a theoretical model which includes the effect of the applied electric field on the carrier generation yield (geminate recombination, Onsager effect). Comparison of experimental and theoretical curves allowed us to determine the values of the main conduction parameters, such as carrier mobility, recombination coefficient, trap densities, for the materials under investigation. (Author)

  1. Protection from ionizing radiation induced damages by phytoceuticals and nutraceuticals

    Exposure of living systems to ionizing radiation cause a variety of damages to DNA and membranes due to generation of free radicals and reactive oxygen species. The radiation induced lesions in the cellular DNA are mainly strand breaks, damage to sugar moiety, alterations and elimination of bases, cross links of the intra and inter strand type and cross links to proteins while peroxidation of the lipids and oxidation of proteins constitute the major lesions in the membranes. The radioprotectors elicit their action by various mechanisms such as i) by suppressing the formation of reactive species, ii) detoxification of radiation induced species, iii) target stabilization and iv) enhancing the repair and recovery processes. The radioprotective compounds are of importance in medical, industrial, environmental, military and space science applications. Radiation protection might offer a tactical advantage on the battlefield in the event of a nuclear warfare. Radioprotectors might reduce the cancer risk to populations exposed to radiations directly or indirectly through industrial and military applications. The antioxidant and radioprotective properties a few of these agents under in vitro and in vivo conditions in animal models will be discussed

  2. Neurolysis and myocutaneous flap for radiation induced brachial plexus neuropathy

    Surgical treatment for radiation induced brachial plexus neuropathy is difficult. We followed 9 patients of radiation induced brachial plexus neuropathy who were surgically treated with neurolysis and myocutaneous flap coverage. Their ages ranged from 29 to 72 years old. Their diagnoses were breast cancer in 6 patients, lingual cancer in 1, thyroid cancer in 1 and malignant lymphoma in 1. Total dose of radiation ranged from 44 to 240 Gy. Interval from radiation therapy to our surgery ranged from 1 to 18 years (mean 6.7 years). Chief complaints were dysesthesia in 9 patients, motor weakness in 7 patients and dullach in scar formation of radiated skin in 7 patients. Preoperative neural functions were slight palsy in 1, moderate palsy in 5 and complete palsy in 3. In surgical treatment, neurolysis of the brachial plexus was done and it was covered by latissimus dorsi myocutaneous flap. We evaluated about dysesthesia and motor recovery after treatment for neuropathy. Follow up periods ranged from 1 to 11 years (average in 5 years). Dysesthesia improved in 6 patients and got worse in 3 patients. Motor weakness recovered in only 2 patients and got worse in 7 patients. From our results, intolerable dysesthesia which was first complaint of these patients improved. But motor function had not recovered. Our treatment was thought to be effective for extraneural factor like an compression neuropathy by scar formation and poor vascularity. But it was not effective for intraneural damage by radiation therapy. (author)

  3. Neurolysis and myocutaneous flap for radiation induced brachial plexus neuropathy

    Hirachi, Kazuhiko; Minami, Akio; Kato, Hiroyuki; Nishio, Yasuhiko [Hokkaido Univ., Sapporo (Japan). School of Medicine; Ohnishi, Nobuki

    1998-11-01

    Surgical treatment for radiation induced brachial plexus neuropathy is difficult. We followed 9 patients of radiation induced brachial plexus neuropathy who were surgically treated with neurolysis and myocutaneous flap coverage. Their ages ranged from 29 to 72 years old. Their diagnoses were breast cancer in 6 patients, lingual cancer in 1, thyroid cancer in 1 and malignant lymphoma in 1. Total dose of radiation ranged from 44 to 240 Gy. Interval from radiation therapy to our surgery ranged from 1 to 18 years (mean 6.7 years). Chief complaints were dysesthesia in 9 patients, motor weakness in 7 patients and dullach in scar formation of radiated skin in 7 patients. Preoperative neural functions were slight palsy in 1, moderate palsy in 5 and complete palsy in 3. In surgical treatment, neurolysis of the brachial plexus was done and it was covered by latissimus dorsi myocutaneous flap. We evaluated about dysesthesia and motor recovery after treatment for neuropathy. Follow up periods ranged from 1 to 11 years (average in 5 years). Dysesthesia improved in 6 patients and got worse in 3 patients. Motor weakness recovered in only 2 patients and got worse in 7 patients. From our results, intolerable dysesthesia which was first complaint of these patients improved. But motor function had not recovered. Our treatment was thought to be effective for extraneural factor like an compression neuropathy by scar formation and poor vascularity. But it was not effective for intraneural damage by radiation therapy. (author)

  4. Allopurinol gel mitigates radiation-induced mucositis and dermatitis

    It has not been verified whether allopurinol application is beneficial in decreasing the severity of radiation-induced oral mucositis and dermatitis. Rats were divided into 4 groups and received 15 Gy irradiation on the left whisker pad. Group 1 received only irradiation. Group 2 was maintained by applying allopurinol/carrageenan-mixed gel (allopurinol gel) continuously from 2 days before to 20 days after irradiation. Group 3 had allopurinol gel applied for 20 days after radiation. Group 4 was maintained by applying carrageenan gel continuously from 2 days before to 20 days after irradiation. The intra oral mucosal and acute skin reactions were assessed daily using mucositis and skin score systems. The escape thresholds for mechanical stimulation to the left whisker pad were measured daily. In addition, the irradiated tissues at the endpoint of this study were compared with naive tissue. Escape threshold in group 2 was significantly higher than that in group 1, and mucositis and skin scores were much improved compared with those of group 1. Concerning escape threshold, mucositis and skin scores in group 3 began to improve 10 days after irradiation. Group 4 showed severe symptoms of mucositis and dermatitis to the same extent as that observed in group 1. In the histopathological study, the tissues of group 1 showed severe inflammatory reactions, compared with those of group 2. These results suggest that allopurinol gel application can mitigate inflammation reactions associated with radiation-induced oral mucositis and dermatitis. (author)

  5. Radiation-induced muscositis and neutrophil granulocytes in oral mucosa

    Background: Chemotherapy-induced mucositis can be related to a decrease in oral neutrophils. We tested the relationship between radiation-induced mucositis and oral neutrophil counts. Patients and Methods: Oral neutrophil counts were obtained for ten patients with head and neck cancer who received radiotherapy of the pharynx and oral cavity. Four patients received additional chemotherapy (5-FU, Mitomycin). Counts were obtained before and during treatment; four healthy volunteers were included in the study as well. For evaluation, a quantitative mouth rinse assay, including neutrophil-staining with acridin-orange, was applied. Results: We observed large inter-individual variations with respect to neutrophil counts for patients and control persons (Table 1). During treatment (irradiation or chemoirradiation), large intra-individual variations were seen additionally (Figure 1). We found a correlation between neutrophil counts and clinical reaction grade. Neutrophil counts increased with increasing mucositis (Figure 2). This increase was more pronounced for patients treated with chemoirradiation compared to radiation alone. Treatment breaks at weekends had no clear influence on neutrophil counts. Conclusions: We observed a weak correlation between neutrophil counts and clinical reaction grade. However, the variations in neutrophil counts are too large to utilize this parameter as a surrogate for clinical mucositis grading. The assumption that a decrease in oral neutrophils is associated with radiation-induced mucositis was clearly negated. (orig.)

  6. Radiation-induced segregation in Cu-Au alloys

    Radiation-induced segregation in a Cu-1 at. % Au alloy was investigated using in situ Rutherford Backscattering Spectrometry. Irradiation with 1.8-MeV He produced nonequilibrium Au atom depletion in the near surface region. The amount of segregation was measured as a function of dose, dose rate and temperature. Segregation was observed between 300 and 5000C. For a calculated dose rate of 3.9 x 10-5 dpa/s, the radiation-induced segregation rate peaked near 4000C. Theoretical analysis based on the Johnson-Lam model predicted that the amount of segregation would be directly proportional to dose at the early stage of irradiation, would deviate from linearity with a continuously decreasing slope at intermediate doses, and finally approach a constant value after high doses. The analysis also predicted that the segregation rate would vary as the -1/4th power of the dose rate at constant dose in the low temperature region. These predictions were all verified experimentally. A procedure for extracting relative defect production efficiencies from similar measurements is discussed

  7. Characterization of radiation-induced emesis in the ferret

    King, G.L.

    1988-06-01

    Forty-eight ferrets (Mustela putorius furo) were individually head-shielded and radiated with bilateral /sup 60/Co gamma radiation at 100 cGy min-1 at doses ranging between 49 and 601 cGy. The emetic threshold was observed at 69 cGy, the ED50 was calculated at 77 cGy, and 100% incidence of emesis occurred at 201 cGy. With increasing doses of radiation, the latency to first emesis after radiation decreased dramatically, whereas the duration of the prodromal period increased. Two other sets of experiments suggest that dopaminergic mechanisms play a minor role in radiation-induced emesis in the ferret. Twenty-two animals were injected either intravenously or subcutaneously with 30 to 300 micrograms/kg of apomorphine. Fewer than 50% of the animals vomited to 300 micrograms/kg apomorphine; central dopaminergic receptor activation was apparent at all doses. Another eight animals received 1 mg/kg domperidone prior to either 201 (n = 4) or 401 (n = 4) cGy radiation and their emetic responses were compared with NaCl-injected-irradiated controls (n = 8). At 201 cGy, domperidone significantly reduced only the total time in emetic behavior. At 401 cGy, domperidone had no salutary effect on radiation-induced emesis. The emetic responses of the ferret to radiation and apomorphine are compared with these responses in other vomiting species.

  8. Characterization of radiation-induced emesis in the ferret

    King, G.L.

    1988-01-01

    Forty-eight ferrets (Mustela putorius furo) were individually head-shielded and radiated with bilateral cobalt 60 gamma radiation at 100 cGy min at doses ranging between 49 and 601 cGy. The emetic threshold was observed at 69 cGy, the ED 50 was calculated as 77 cGy, and 100% incidence of emesis occurred at 201 cGy. With increasing doses of radiation, the latency to first emesis after radiation decreased dramatically, whereas the duration of the prodromal period increased. Two other sets of experiments suggest that dopaminergic mechanisms play a minor role in radiation-induced emesis in the ferret. Twenty-two animals were injected either intravenously or subcutaneously with 30 to 300 micrograms /kg of apomorphine. Fewer than 50% of the animals vomited to 300 micrograms/kg apomorphine; central dopaminergic receptor activation was apparent at all doses. Another eight animals received 1 mg/kg domperidone prior to either 201 (n=4) or 401 (n=4) cGy radiation and their emetic responses were compared with NaCi-injected-irradiated controls (n=8). At 201 cGy, domperidone significantly reduced only the total time in emetic behavior. At 401 cGy, domperidone had no salutary effect on radiation-induced emesis. The emetic responses of the ferret to radiation and apomorphine are compared with these responses in other vomiting species.

  9. Radiation-induced grafting of styrene on polypropylene pellets

    The changes of radiation-induced in polypropylene (PP) pellets exposed to gamma irradiation in inert atmosphere were investigated in correlation with the applied doses (10 and 50 kGy). Also, results from the grafting of styrene onto PP pellets using simultaneous irradiation at the same doses are presented. The grafting reaction was carried out using toluene as solvent, under nitrogen atmosphere and at room temperature. The properties of the irradiated and grafted PP pellets were studied using Melt Flow Index, thermal analysis (TG and DSC), and ATR-IR. The degree of grafting (DOG) for the grafted pellets was gravimetrically determined. The results showed that radiation-induced graft polymerization on pellets were successfully obtained and the influence of dose irradiated did not change the thermal properties in spite of the increase in the MFI and consequently this increase in the viscosity results an decrease the molecular mass. The MFI for grafted pellets was not achievable because the high degree of viscosity of polymer, even arising the test temperature, the polymer was not flow enough. (author)

  10. ROS Mediates Radiation-Induced Differentiation in Human Lung Fibroblast

    Park, Sa Rah; Ahn, Ji Yeon; Kim, Mi Hyeung; Lim, Min Jin; Yun, Yeon Sook; Song, Jie Young [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of)

    2009-05-15

    One of the most common tumors worldwide is lung cancer and the number of patients with lung cancer received radiotherapy is increasing rapidly. Although radiotherapy may have lots of advantages, it can also induce serious adverse effects such as acute radiation pneumonitis and pulmonary fibrosis. Pulmonary fibrosis is characterized by excessive production of smooth muscle actin-alpha (a-SMA) and accumulation of extracellular matrix (ECM) such as collagen and fibronectin. There has been a great amount of research about fibrosis but the exact mechanism causing the reaction is not elucidated especially in radiation-induced fibrosis. Until now it has been known that several factors such as transforming growth factor (TGF-b), tumor necrosis factor (TNF), IL-6, platelet-derived growth factor (PDGF) and reactive oxygen species are related to fibrosis. It is also reported that reactive oxygen species (ROS) can be induced by radiation and can act as a second messenger in various signaling pathways. Therefore we focused on the role of ROS in radiation induced fibrosis. Here, we suggest that irradiation generate ROS mainly through NOX4, result in differentiation of lung fibroblast into myofibroblast.

  11. Nature of radiation-induced defects in quartz

    Although quartz (α-form) is a mineral used in numerous applications wherein radiation exposure is an issue, the nature of the atomistic defects formed during radiation-induced damage has not been fully clarified. Especially, the extent of oxygen vacancy formation is still debated, which is an issue of primary importance as optical techniques based on charged oxygen vacancies have been utilized to assess the level of radiation damage in quartz. In this paper, molecular dynamics simulations are applied to study the effects of ballistic impacts on the atomic network of quartz. We show that the defects that are formed mainly consist of over-coordinated Si and O, as well as Si–O connectivity defects, e.g., small Si–O rings and edge-sharing Si tetrahedra. Oxygen vacancies, on the contrary, are found in relatively low abundance, suggesting that characterizations based on E′ centers do not adequately capture radiation-induced structural damage in quartz. Finally, we evaluate the dependence on the incident energy, of the amount of each type of the point defects formed, and quantify unambiguously the threshold displacement energies for both O and Si atoms. These results provide a comprehensive basis to assess the nature and extent of radiation damage in quartz

  12. Optical bleaching of radiation-induced colour centres in fluorapatite

    One of the important steps in thermoluminescence (TL) dating studies is the assessment of the total natural radiation dose that a sample has received and retained. This, in turn, depends on the thermal and temporal stabilities as well as the optical bleaching of the radiation-induced colour centres. In this paper, we report the effect of selective optical bleaching, after X-irradiation, on the TL glow curves of synthetic fluorapatite. X-irradiated fluorapatite exhibits three unresolved TL peaks around 150, 250 and 345 C. Diffuse reflectance studies of the polycrystalline fluorapatite show that X-irradiation induces absorption bands at 370 and 450 nm. Furthermore, exposure to light through 320 to 400 nm and 400 to 480 nm band filters effectively bleaches the TL glow from the first two peaks at around 150 and 250 C. By correlating the wavelength of light used for bleaching the TL with the radiation-induced absorption bands, the type of centres involved in the approx. 150 C TL glow peak in fluorapatite has been identified as E(II) or A centres, i.e. halogen ion vacancies with trapped electrons. Although the approx. 250 C TL glow peak is also bleached along with the 150 C TL peak, its temperature stability does not agree with that of the A centres. (author)

  13. Radiation induced effects and annealing methods in fiberoptics and glasses

    Radiation induced effects in glass-rods and fiberoptics have been studied to determine parameters affecting the application of these materials in nuclear technology, i.e. as fiberscopes for visual inspection in severe radiation environments. Different glass and fibertypes have been exposed to fission product gamma radiation. The radiation induced transmission loss was measured with a spectrophotometer and then different annealing methods were examined to improve the transmission properties again. Especially the changes in glass and fiber recovery vs. time as a function of radiation dose and annealing temperature were investigated. Annealing experiments were performed exposing the samples either to temperature treatment or to various light sources such as quartz lamp, arc lamp or UV-laser for optical annealing. The transmission recovery was then investigated either as a function of annealing temperature or of exposure time to the light sources. The results allow conclusions on the design and composition of optical fiber endoscopes to be used in severe radiation environment where image transmission is required in the presence of high level nuclear radiation. (author)

  14. Ionizing Radiation Induces HMGB1 Cytoplasmic Translocation and Extracellular Release

    Lili Wang; Li He; Guoqiang Bao; Xin He; Saijun Fan; Haichao Wang

    2016-01-01

    Objective A nucleosomal protein,HMGBI,can be secreted by activated immune cells or passively released by dying cells,thereby amplifying rigorous inflammatory responses.In this study we aimed to test the possibility that radiation similarly induces cytoplasmic HMGB1 translocation and release.Methods Human skin fibroblast (GM0639) and bronchial epithelial (16HBE) cells and rats were exposed to X-ray radiation,and HMGB1 translocation and release were then assessed by immunocytochemistry and immunoassay,respectively.Results At a wide dose range(4.0-12.0 Gy),X-ray radiation induced a dramatic cytoplasmic HMGB1 translocation,and triggered a time-and dose-dependent HMGB1 release both in vitro and in vivo.The radiation-mediated HMGB1 release was also associated with noticeable chromosomal DNA damage and loss of cell viability.Conclusions Radiation induces HMGB1 cytoplasmic translocation and extracellular release through active secretion and passive leakage processes.

  15. Radiation induced effects in the developing central nervous system

    The embryo and the human foetus are particularly sensitive to ionizing radiation and this sensitivity presents various qualitative and quantitative functional changes during intra-uterine development. Apart from radiation induced carcinogenesis, the most serious consequence of prenatal exposure in human beings is severe mental retardation. The principal data on radiation effects on human beings in the development of the central nervous system come form epidemiological studies carried out in individuals exposed in utero during the atomic explosion at Hiroshima and Nagasaki. These observations demonstrate the existence of a time of maximum radiosensitivity between the weeks 8 and 15 of the gestational period, a period in which the proliferation and neuronal migration takes place. Determination of the characteristics of dose-response relationship and the possible existence of a threshold dose of radiation effects on the development of the central nervous system is relevant to radiation protection against low dose radiation and the establishment of dose limits for occupational exposure and the public. Studies were conducted on the generation of nitrous-oxide and its relation with the production of active species of oxygen in brains of exposed rats in utero exposed to doses of up to 1 Gy during their maximum radiosensitivity. The possible role of the mechanism of radiation induced damage in the development of the central nervous system is discussed

  16. The thermal stability of radiation-induced defects in illite

    Riegler, T.; Allard, T.; Beaufort, D.; Cantin, J.-L.; von Bardeleben, H. J.

    2016-01-01

    High-purity illite specimens from the Mesoproterozoic unconformity-related uranium deposits of Kiggavik, Thelon basin, Nunavut (Canada), and Shea Creek (Athabasca basin, Saskatchewan, Canada) have been studied using electron paramagnetic resonance spectroscopy to determine the thermal stability of the main radiation-induced defects and question the potential of using illite as a natural dosimeter. The observed spectra are complex as they can show in the same region several contributions: (1) an unstable native defect, (2) the main stable defect named Ai by reference to a previous study (Morichon et al. in Phys Chem Minerals 35:339-346, 2008), (3) a signal at g = 2.063 assigned to a new defect, not yet fully characterized, named Ai2 center and (4) impurities such as vanadyl complex or divalent manganese. Isochronal heating shows that the new signal corresponds to a stable species. Isothermal heating experiments at 400 and 450 °C provide values of half-life extrapolated at room temperature and activation energy of 1.9-29,109 years and 1.3-1.4 eV, respectively, corresponding to the Ai center. These parameters allow the use of stable radiation-induced defects as a record of radioactivity down to the Paleoproterozoic period.

  17. Simvastatin attenuates radiation-induced tissue damage in mice

    The aim of this study was to investigate the protective effect of simvastatin against radiation-induced tissue injury in mice. Mice were radiated with 4 Gy or 8 Gy after 20 mg/kg/d simvastatin treatment over 2 weeks. Morphological changes were observed in the jejunum and bone marrow, and apoptotic cells were determined in both tissues. Peripheral blood cells were counted, and the superoxide dismutase (SOD) activity and the malondialdehyde (MDA) level in tissues of both thymus and spleen were measured. Compared with the radiation-only group, 20 mg/kg/d simvastatin administration significantly increased the mean villi height and decreased apoptotic cells in jejunum tissue, and stimulated regeneration and reduced apoptotic cells in bone marrow. Peripheral blood cell analysis revealed that simvastatin treatment induced a larger number of red blood cells and increased the hemoglobin level present after 4 Gy of radiation. Interestingly, it was also found that the number of peripheral endothelial progenitor cells was markedly increased following simvastatin administration. Antioxidant determination for tissues displayed that simvastatin therapy increased the SOD activity after both 4 and 8 Gy of radiation, but only decreased the MDA level after 4 Gy. Simvastatin ameliorated radiation-induced tissue damage in mice. The radioprotective effect of simvastatin was possibly related to inhibition of apoptosis and improvement of oxygen-carrying and antioxidant activities. (author)

  18. Radiation induced segregation and point defects in binary copper alloys

    Considerable progress, both theoretical and experimental, has been made in establishing and understanding the influence of factors such as temperature, time, displacement rate dependence and the effect of initial solute misfit on radiation induced solute diffusion and segregation. During irradiation, the composition of the alloy changes locally, due to defect flux driven non-equilibrium segregation near sinks such as voids, external surfaces and grain boundaries. This change in composition could influence properties and phenomena such as ductility, corrosion resistance, stress corrosion cracking, sputtering and blistering of materials used in thermo-nuclear reactors. In this work, the effect of 1 MeV electron irradiation on the initiation and development of segregation and defect diffusion in binary copper alloys has been studied in situ, with the aid of a high voltage electron microscope. The binary copper alloys had Be, Pt and Sn as alloying elements which had atomic radii less than, similar and greater than that of copper, respectively. It has been observed that in a wide irradiation temperature range, stabilization and growth of dislocation loops took place in Cu-Sn and Cu-Pt alloys. Whereas in the Cu-Be alloy, radiation induced precipitates formed and transformed to the stable γ phase. (Author)

  19. Radiation-induced cationic polymerization of vinyl ethers in solution

    The influences of the polymerization media, the monomer and solvent concentrations and the temperature on the radiation-induced polymerization of isopropyl vinyl ether (IPVE) have been studied in detail under super-dry conditions. Rates of polymerization were measured and estimates of the rate constants of polymerization were calculated according to the simplified Hayashi-Williams equation. A comparison of the results with those previously reported for ethyl vinyl ether (EVE) is made. The much higher reactivity of IPVC in low polar solvents is interpreted by a drastic reduction of the polymer intramolecular solvation of the growing chain ends. This is ascribed to the bulkiness of the isopropyl side-chain groups. The radiation-induced polymerization of IPVE in bulk and in various solvents with different physical and solvating properties was studied. This was to obtain further information on the kinetics and the mechanisms involved with this monomer and also the role of the polymerization media. The influence of the monomer and solvent concentrations and of the polymerization temperature on the rate of polymerization have also been investigated. (author)

  20. Radiation-induced mucositis pain in laryngeal cancer

    Radiation therapy in those with head and neck malignancies often triggers painful mucositis poorly controlled by nonsteroidal antiinflammatory drugs (NSAIDs). To better understand how radiation-induced pain develops over time, we studied the numerical rating scale (NRS 0-5) pain scores from 32 persons undergoing radiation therapy of 60-72 Gy for newly diagnosed laryngeal cancer. The degree of mucositis was evaluated using Common Terminology Criteria for Adverse Events version3.0 (CTCAE v3.0). We divided the 32 into a conventional fractionation (CF) group of 14 and a hyperfractionation (HF) group of 18, and further divided laryngeal cancer into a small-field group of 23 and a large-field group of 9. The mucositis pain course was similar in CF and HF, but mucositis pain was severer in the HF group, which also required more NSAIDs. Those in the large-field group had severer pain and mucositis and required more NSAIDs than those in the small-field group. We therefore concluded that small/large-field radiation therapy, rather fractionation type, was related to the incidence of radiation-induced mucositis pain. (author)

  1. Inhibition of radiation-induced polyuria by histamine receptor antagonists

    In previous studies the authors have demonstrated that gamma radiation results in polyuria, which is preceded by polydypsia. This suggests that the increased thirst elicited by radiation causes increased urinary volume (UV). Histamine, which is released following radiation exposure, also elicits drinking by nonirradiated rats when administered exogenously. In this study the authors have investigated both the role of water deprivation and the effect of histamine receptor antagonists (HRA) on radiation-induced polyuria. Sprague-Dawley rats were housed individually in metabolic cages. Water was allowed ad libitum except in deprivation experiments where water was removed for 24 hr immediately following radiation. Cimetidine (CIM), an H2 HRA, and dexbromopheniramine (DXB), an H1 HRA, were administered i.p. (16 and 1 mg/kg, respectively) 30 min prior to irradiation (950 rads from a cobalt source). UV was determined at 24-hr intervals for 3 days preceding irradiation and 24 hr postirradiation. UV in DXB treated rats was significantly reduced 24 hr postirradiation (CON = 427 +/- 54%; DXB = 247 +/- 39% of preirradiated CON) compared to postirradiation control values. CIM did not affect postirradiation UV. These data suggest that radiation-induced polyuria is caused by polydypsia which is, in part, mediated by histamine induced by an H1 receptor

  2. Hyperbaric oxygen therapy for radiation-induced hemorrhagic cystitis

    Hyperbaric oxygen (HBO) therapy has recently emerged as a potential primary option for the management of hemorrhagic cystitis. We review our experience treating hemorrhagic cystitis with HBO. Between January 2001 and May 2007, eight patients with radiation-induced hemorrhagic cystitis underwent HBO therapy. There were five men and three women with a mean age of 64.3 years (47-73). Radiation was given for local disease, and the mean dosage delivered was 56.6 Gy (42-70). The mean duration between the onset of hematuria and the beginning of HBO therapy was 8.9 months (3-34). Mean follow-up period was 15.5 months (2-31). Hematuria resolved completely in six of the eight patients, one of whom suffered recurrence of hematuria and was treated with HBO until the hematuria resolved again. The response rate was 75%, compatible with the previous reports, and no side-effects of HBO were noted. HBO treatment should be attempted for radiation-induced hemorrhagic cystitis. (author)

  3. The redox homeostasis system in radiation-induced genome instability

    The participation of the redox homeostasis system in the formation of the radiation-induced genome instability and new data of literature, that give a direct evidence the presence of this instability in vivo, is considered. The O2- radical, H2O2 and NO radical role as signal molecules, that trigger the cascade of active responses to change of redox status of the cells, are discussed. The reactive oxygen species (ROS) reorganize the membrane physico-chemical system of cell metabolism regulation. The data about changes in ROS generation system, including NO, that lead to genome instability after ionizing irradiation even in low doses, are analyzed. It is noted, that the radiation-induced genome instability and ROS production increase may be observed both in direct irradiated cells and their progeny and in the cells, that are not find oneself in ionization tracks, and their progeny. There evidences that the genome instability of irradiated cell progeny is maintained by the increases ROS production

  4. Radiation-induced electron migration in nucleic acids

    Radiation-induced electron migration along DNA is a mechanism by which randomly produced stochastic energy deposition events can lead to non-random types of damage along DNA manifested distal to the sites of the initial energy deposition. Radiation-induced electron migration in nucleic acids has been examined using oligonucleotides containing 5-bromouracil (5-BrU). Interaction of 5-BrU with solvated electrons results in release of bromide ions and formation of uracil-5-yl radicals. Monitoring either bromide ion release or uracil formation provides an opportunity to study electron migration processes in model nucleic acid systems. Using this approach we have discovered that electron migration along oligonucleotides is significantly influenced by the base sequence and strandedness. Migration along 7 base pairs in oligonucleotides containing guanine bases was observed for oligonucleotides irradiated in solution, which compares with mean migration distances of 6-10 bp for Escherichia coli DNA irradiated in solution and 5.5 bp for E. coli DNA irradiated in cells. Evidence also suggests that electron migration can occur preferentially in the 5' to 3' direction along a double-stranded oligonucleotide containing a region of purine bases adjacent to the 5-BrU moiety. Our continued efforts will provide information regarding the contribution of electron transfer along DNA to formation of locally multiply damaged sites created in DNA by exposure to ionizing radiation. (Author)

  5. Mechanism of enhancement of radiation-induced cytotoxicity by sorafenib in colorectal cancer

    Kim, Yong Bae; Jeung, Hei-Cheul; Jeong, Inhye; Lee, KyungHwa; Rha, Sun Young; Chung, Hyun Cheol; Kim, Gwi Eon

    2012-01-01

    Sorafenib, an orally available multikinase inhibitor, combined with radiation has shown potential as an anticancer treatment in an in vitro and in vivo colon cancer model. In this study, we investigated the mechanism of enhancement of radiation-induced cytotoxicity by sorafenib in colorectal cancer. The effects of sorafenib on radiation-induced cytotoxicity of DLD-1 and HT-29 were evaluated via clonogenic assay. The impact of sorafenib on radiation-induced cell cycle kinetics and on apoptosis...

  6. Effect of pH on radiation-induced apoptosis

    Purpose/Objective: The effect of environmental pH on the radiation-induced apoptosis in tumor cells in vitro was investigated. Materials and Methods: SCK mammary adenocarcinoma cells of A/J mice were irradiated with γ-rays using a 137Cs irradiator and incubated in media of different pHs. After incubation at 37 degree sign C for 24-120 hrs., the extent of apoptosis was determined using agarose gel electrophoresis of DNA, in situ TUNEL staining, flow cytometry, and release of 3H from 3H-thymidine labeled cells. The membrane integrity, using the trypan blue exclusion method, and the clonogenicity of the cells were also determined. Results: Irradiation with 2-12 Gy of γ-rays induced apoptosis in pH 7.5 medium within 48 hrs. The radiation-induced apoptosis progressively declined as the medium pH was lowered so that little apoptosis occurred in 48 hrs. after irradiation with 12 Gy in pH 6.6 medium. However, when the cells were irradiated and incubated for 48 hrs. in pH 6.6 medium and then medium was replaced with pH 7.5 medium, apoptosis promptly occurred. Apoptosis also occurred even in pH 6.6 medium when the cells were irradiated and maintained in pH 7.5 medium for 8 hrs. or longer post-irradiation before incubation in pH 6.6 medium. Conclusion: An acidic environment markedly suppresses radiation-induced apoptosis probably by suppressing the expression of initial signals responsible for irradiation-induced apoptosis. Indications are that the signals persist in an acidic environment and trigger apoptosis when the environmental acidity is eased. Our results suggest that the acidic environment in human tumors may inhibit the apoptosis after irradiation. However, apoptosis may be triggered when reoxygenation occurs after irradiation, and thus, the intratumor environment becomes less acidic after irradiation. Not only the change in pO2 but the change in pH during the course of fractionated radiotherapy may greatly influence the outcome of the treatment

  7. Radiation induced crystallinity damage in poly(L-lactic acid)

    The radiation-induced crystallinity damage in poly(L-lactic acid) (PLLA) in the presence of air and in vacuum, is studied. From the heat of fusion enthalpy values of gamma irradiated samples, some changes on the thermal properties were determined. To identify these changes, first the glass transition temperature (Tg) of L-lactic acid polymers irradiated to various doses in air and vacuum have been investigated and it is found that it is independent of irradiation atmosphere and dose. The fraction of damaged units of PLLA per unit of absorbed energy has been measured. For this purpose, SAXS and differential scanning calorimetry methods were used, and the radiation yield of number of damaged units (G(-u)) is found to be 0.74 and 0.58 for PLLA samples irradiated in vacuum and air, respectively

  8. Radiation induced crystallinity damage in poly(L-lactic acid)

    Kantoglu, O

    2002-01-01

    The radiation-induced crystallinity damage in poly(L-lactic acid) (PLLA) in the presence of air and in vacuum, is studied. From the heat of fusion enthalpy values of gamma irradiated samples, some changes on the thermal properties were determined. To identify these changes, first the glass transition temperature (T sub g) of L-lactic acid polymers irradiated to various doses in air and vacuum have been investigated and it is found that it is independent of irradiation atmosphere and dose. The fraction of damaged units of PLLA per unit of absorbed energy has been measured. For this purpose, SAXS and differential scanning calorimetry methods were used, and the radiation yield of number of damaged units (G(-u)) is found to be 0.74 and 0.58 for PLLA samples irradiated in vacuum and air, respectively.

  9. Radiation induced DNA double-strand breaks in radiology

    Shortly after the discovery of X-rays, their damaging effect on biological tissues was observed. The determination of radiation exposure in diagnostic and interventional radiology is usually based on physical measurements or mathematical algorithms with standardized dose simulations. γ-H2AX immunofluorescence microscopy is a reliable and sensitive method for the quantification of radiation induced DNA double-strand breaks (DSB) in blood lymphocytes. The detectable amount of these DNA damages correlates well with the dose received. However, the biological radiation damage depends not only on dose but also on other individual factors like radiation sensitivity and DNA repair capacity. Iodinated contrast agents can enhance the x-ray induced DNA damage level. After their induction DSB are quickly repaired. A protective effect of antioxidants has been postulated in experimental studies. This review explains the principle of the γ-H2AX technique and provides an overview on studies evaluating DSB in radiologic examinations.

  10. Radiation-induced conductivity in poly(phenylene vinylene) derivatives

    Using the pulse-radiolysis time-resolved microwave conductivity technique the mobility and decay kinetics of radiation-induced charge carriers is studied in a series of poly(2,5-dialkoxy-phenylene vinylene) derivatives. The lower limit to the sum of the mobilities of the positive and negative charge carriers, Σμmin, depends strongly on the alkoxy functionalization and ranges from 1.2 x 10-7 to 1.4 x 10-6 m2/V x s at room temperature. Σμmin increases with the degree of order in the material. The after-pulse conductivity decay kinetics are disperse and are controlled by a combination of charge recombination and trapping. (author)

  11. Radiatively Induced Breaking of Conformal Symmetry in a Superpotential

    Arbuzov, A B

    2015-01-01

    Radiatively induced symmetry breaking is considered for a toy model with one scalar and one fermion field unified in a superfield. It is shown that the classical quartic self-interaction of the superfield possesses a quantum infrared singularity. Application of the Coleman-Weinberg mechanism for effective potential leads to the appearance of condensates and masses for both scalar and fermion components. That induces a spontaneous breaking of the initial classical symmetries: the supersymmetry and the conformal one. The energy scales for the scalar and fermion condensates appear to be of the same order, while the renormalization scale is many orders of magnitude higher. A possibility to relate the considered toy model to conformal symmetry breaking in the Standard Model is discussed.

  12. Radiation-induced spindle cell sarcoma: A rare case report

    Khan Mubeen

    2009-01-01

    Full Text Available Ionizing radiation has been known to induce malignant transformation in human beings. Radiation-induced sarcomas are a late sequel of radiation therapy. Most sarcomas have been reported to occur after exposure to a radiation dose of 55 Gray (Gy and above, with a dose ranging from 16 to 112 Gys. Spindle cell sarcomas, arising after radiotherapy given to treat the carcinoma of head and neck region is a very uncommon sequel. This is a rare case report of spindle cell sarcoma of left maxilla, in a 24-year-old male, occurring as a late complication of radiotherapy with Cobalt-60 given for the treatment of retinoblastoma of the left eye 21 years back.

  13. The radiation-induced grafting of vinylpyridines to cellulose

    A wide range of solvents have been examined for the radiation-induced grafting to cellulose of 2- and 4-vinylpyridines and 2-methyl-5-vinylpyridine by the mutual irradiation technique. The presence of a functional group containing a nitrogen and/or oxygen atom in the solvent is important for high grafting efficiency. The two most favourable groups are NH2 and OH, the former being the more effective. Inclusion of both groups in suitable positions in the one molecule, the aminoalkanols in particular (e.g. 2-aminoethanol), leads to maximum effect in grafting. Heterocyclic solvents such as pyridine and 3-picoline are also useful. Other variables affecting grafting and studied in these experiments were the effect of pK, as well as swelling, wetting and dielectric strength of solvents. The effect of surface area of cellulose on copolymerization was also examined. A novel ionic mechanism for the grafting reaction involving association between solvent and monomer is proposed. (Author)

  14. Modification of microcystalline cellulose by gamma radiation-induced grafting

    Modified crystalline cellulose (MCC) was prepared through gamma radiation-induced graft polymerization of glycidyl methacrylate (GMA). Simultaneous grafting was employed wherein MCC with GMA in methanol was irradiated with gamma radiation in nitrogen atmosphere. The effects of different experimental factors such as monomer concentration, type of solvent and absorbed dose on the degree of grafting, Dg, were studied. The amount of grafted GMA, expressed as Dg, was determined gravimetrically. Information from grafted samples subjected to Fourier transformed infrared spectroscopy (FTIR) in attenuated total reflectance (ATR) mode showed peaks corresponding to GMA which indicates successful grafting. The X-ray diffraction (XRD) analysis revealed that the crystalline region of MCC was not adversely affected after grafting with GMA. The thermogravimetric analysis (TGA) data showed that the decomposition of grafted MCC occurred at higher temperature compared to the base MCC polymer. (author)

  15. Factors that modify risks of radiation-induced cancer

    The collective influence of biologic and physical factors that modify risks of radiation-induced cancer introduces uncertainties sufficient to deny precision of estimates of human cancer risk that can be calculated for low-dose radiation in exposed populations. The important biologic characteristics include the tissue sites and cell types, baseline cancer incidence, minimum latent period, time-to-tumor recognition, and the influence of individual host (age and sex) and competing etiologic influences. Physical factors include radiation dose, dose rate, and radiation quality. Statistical factors include time-response projection models, risk coefficients, and dose-response relationships. Other modifying factors include other carcinogens, and other biological sources (hormonal status, immune status, hereditary factors)

  16. Radiatively induced breaking of conformal symmetry in a superpotential

    Arbuzov, A. B.; Cirilo-Lombardo, D. J.

    2016-07-01

    Radiatively induced symmetry breaking is considered for a toy model with one scalar and one fermion field unified in a superfield. It is shown that the classical quartic self-interaction of the superfield possesses a quantum infrared singularity. Application of the Coleman-Weinberg mechanism for effective potential leads to the appearance of condensates and masses for both scalar and fermion components. That induces a spontaneous breaking of the initial classical symmetries: the supersymmetry and the conformal one. The energy scales for the scalar and fermion condensates appear to be of the same order, while the renormalization scale is many orders of magnitude higher. A possibility to relate the considered toy model to conformal symmetry breaking in the Standard Model is discussed.

  17. An integrated model for radiation induced cancer (IMRIC)

    The ultimate aim for radiation induced cancer modeling must be to arrive at cancer risk estimates in the human, based (partly or entirely) on data obtained in the laboratory. Current risk estimates for the stochastic radiation effect of cancer induction derive entirely from epidemiological data, largely of the Japanese survivors of the A-bombs, with little input of laboratory information. These data relate to high doses and high dose-rates and it is difficult to see how much more information can be extracted from them. Because of rapid progress in many fields, including molecular biology, cellular studies and experiments with laboratory animals, it is argued here that the time is now ripe for an attempt to be made to model the entire sequence of events from the absorption of radiation energy to the manifestation of a malignancy in the human. (author)

  18. Radiation-induced degradation of 4-chloroaniline in aqueous solution

    The radiation-induced decomposition of 4-chloroaniline (4-ClA) was studied under steady-state conditions using aqueous solutions saturated with air, pure oxygen, N2O, argon and argon in the presence of t-Butanol. Using HPLC-method, the initial G-values of the substrate degradation as well as of a number of radiolytic products were determined. The formation of aminophenols, chlorophenols, aniline and phenol in addition to chloride, ammonia, formaldehyde and mixture of aldehydes as well as carboxylic acids was studied as a function of absorbed dose. Based on the experimental data, probable reaction mechanisms for the degradation of 4-ClA by γ-rays and the formation of the identified products are presented

  19. Radiation-induced coronary artery disease. One observation

    Twenty-seven reports (26 from the literature) of radiation ischemic heart diseases are studied in order to specify their clinical and pathological findings and their natural history. This complications appear after treatment of radiation-curable diseases with a mean delay of 4 years in young patients (mean age of 31). Several coronary arteries are often injuried with fibrous and or atherosclerotic anatomical lesions. The frequency of this coronary artery diseases is certainly more important than reported since they are often latent but probably progressive. However, atherogenetic factors increase the risk and must be lowered in a preventive aim; as a rule, the radiotherapic technique must also be as perfect as possible. The prognosis of this radiation induced coronary artery diseases is poor: 19 myocardial infarctions and 12 deaths are observed but no cardiac death occured in patients who received a by-pass graft. So, radiation ischemic heart disease needs active investigation and therapy

  20. Binding of radiation-induced phenylalanine radicals to DNA

    When an aqueous solution of double-stranded DNA of bacteriophage PM2 containing phenylalanine and saturated with N2O is irradiated with γ-rays, radiation-induced phenylalanine radicals are bound covalently. Under the conditions used about 25 phenylalanine molecules may be bound per lethal hit. Also for single-stranded PM2 DNA, most of the phenylalanine radicals bound are non-lethal. Evidence is presented that in double-stranded DNA an appreciable fraction of the single-strand breaks is induced by phenylalanine radicals. Radiation products of phenylalanine and the phenylalanine bound to the DNA decrease the sensitivity of the DNA to the induction of single-strand breaks. There are indications that the high efficiency of protection by radiation products of phenylalanine is due to their positive charge, which will result in a relatively high concentration of these compounds in the vicinity of the negatively charged DNA molecules

  1. HSP25 Protects Radiation-Induced Salivary Gland Damage

    Irradiation (IR) is a central treatment modality administered for head and neck malignancies. A significant consequence of this IR treatment is irreversible damage to salivary gland in the IR field. While the exact mechanism of salivary gland damage remains enigmatic, fluid secreting acinar cells are lost, and saliva output is dramatically reduced. Previously we have reported that heat shock protein 25 (HSP25) induced radioresistance in vitro. HSP25 interferes negatively with apoptosis through several pathways which involve its direct interaction with cytochrome c, protein kinase c delta or Akt. And localized gene transfer to salivary glands has great potential for the treatment of salivary gland. Herein, we investigated whether HSP25 can use as radio protective molecules for radiation-induced salivary gland damage in vivo

  2. Radiation-induced radicals in hydrated magnesium sulfate

    Radiation-induced free radicals in hydrated magnesium sulfate, which are thought to be present on the surface of Europa, one of the Jovian moons, have been studied by electron spin resonance (ESR). ESR signals of both atomic hydrogen (H·) at g = 2.0023 and sulfite radical (SO3−·) at g = 2.0029 are observed in epsomite (MgSO4·7H2O) and in quenched samples of magnesium sulfate solutions, after gamma-ray irradiation at 77 K. Atomic hydrogen disappears at temperatures above 90 K. The sulfite radical starts to decay above 190 K in the quenched sample of 10% magnesium sulfate solution, whereas in epsomite, it is stable even at 260 K. The sulfite radical accumulates at low ambient temperatures, and is a promising candidate for estimating the age of hydrated magnesium sulfate, especially in extraterrestrial environments.

  3. Promotion of radiation-induced cationic polymerization by onium salts

    The radiation-induced cationic polymerization of styrene derivatives was studied in the presence of diphenyliodonium and triphenylsulfonium hexafluorophosphates in dichloromethane. A remarkable promotion of the polymerization was observed in the presence of the salts. The pulse radiolysis study revealed that the promotion of the polymerization is due to the ion-pair formation between the initiating cations and the nonnucleophilic complex metal halide anions of the salts resulting in the stabilization of the cations toward neutralization. An additional effect observed in the case of diphenyliodonium salt is the oxidation of free radical species to the cations responsible for the polymerization. An increase in molecular weight at low temperature suggested that the propagating cations are also paired with the counterions derived from the salts. (author)

  4. Radiation-induced mucositis pain in mesopharyngeal and hypopharyngeal cancer

    Radiation therapy in head and neck malignancy often triggers painful mucositis poorly controlled by nonsteroidal antiinflammatory drugs (NSAIDs). To better understand how radiation-induced pain develops over time, we studied numerical rating scale (NRS 0-5) pain scores in 27 subjects undergoing 60-72 Gy radiation therapy for newly diagnosed cancer- 13 with mesopharynx and 14 with hypopharynx. Mucositis severity was evaluated using Common Terminology Criteria for Adverse Events version 3.0 (CTCAE v3.0) based on mucositis pain, analgesic administration, and oral feedings of our subjects, with 8 mesopharyngeal and 10 with hypopharyngeal cancer had been pain-free before radiation therapy. The mucositis and pain course was severer in mesopharyngeal than in hypopharyngeal cancer. NSAIDs and opioid use was similar in both cancer types, which also required tube feeding in 7 subjects (38.9%). (author)

  5. Acupuncture treatment of patients with radiation-induced xerostomia

    Blom, M.; Dawidson, I.; Johnson, G.; Angmar-Maansson, B. [Karolinska Inst., Huddinge (Sweden). Dept. of Cardiology; Fernberg, J.-O. [Karolinska Hospital, Stockholm (Sweden). Dept. of General Oncology

    1996-05-01

    Xerostomia is a common and usually irreversible side effect in patients receiving radiation therapy (>50 Gy) for head and neck cancer. Of 38 patients with radiation-induced xerostomia, 20 in the experimental group were treated with classical acupuncture and 18 patients in the control group received superficial acupuncture as placebo. Within both groups the patients showed significantly increased salivary flow rates after the acupuncture treatment. In the experimental group 68% and in the control group 50% of the patients had increased salivary flow rates at the end of the observation period. Among those patients who had had all their salivary glands irradiated, 50% in both groups showed increased salivary flow rates (>20%) by the end of the observation period of 1 year. The study indicates that among the patients who had increased salivary flow rates already after the first 12 acupuncture sessions, the majority had high probability of continual improvement after the completion of acupuncture treatment. (Author).

  6. Acupuncture treatment of patients with radiation-induced xerostomia

    Xerostomia is a common and usually irreversible side effect in patients receiving radiation therapy (>50 Gy) for head and neck cancer. Of 38 patients with radiation-induced xerostomia, 20 in the experimental group were treated with classical acupuncture and 18 patients in the control group received superficial acupuncture as placebo. Within both groups the patients showed significantly increased salivary flow rates after the acupuncture treatment. In the experimental group 68% and in the control group 50% of the patients had increased salivary flow rates at the end of the observation period. Among those patients who had had all their salivary glands irradiated, 50% in both groups showed increased salivary flow rates (>20%) by the end of the observation period of 1 year. The study indicates that among the patients who had increased salivary flow rates already after the first 12 acupuncture sessions, the majority had high probability of continual improvement after the completion of acupuncture treatment. (Author)

  7. A preliminary report on radiation-induced stimulation in rice

    Radiation-induced stimulation is an oft-reported but controversial phenomenon. Rice var D-6-2-2 was tested for stimulation of yield using 60Co gamma-rays (500R - 100kR) and X-rays (100R - 5kR). Moisture variation was also used as a sub-treatment. Stimulation of both grain and straw yield was observed with both types of radiation but at different doses and varying with moisture conditions. Greenhouse experiments on seedling growth and laboratory experiments on germination rate, water uptake and other physiological processes, show that stimulation exhibited at a very early stage of growth, can be correlated to final yield. It might thus be possible to do primary screening for yield response by seedling performance of the varieties. (author)

  8. Probabilistic methodology for estimating radiation-induced cancer risk

    The RICRAC computer code was developed at Oak Ridge National Laboratory to provide a versatile and convenient methodology for radiation risk assessment. The code allows as input essentially any dose pattern commonly encountered in risk assessments for either acute or chronic exposures, and it includes consideration of the age structure of the exposed population. Results produced by the analysis include the probability of one or more radiation-induced cancer deaths in a specified population, expected numbers of deaths, and expected years of life lost as a result of premature fatalities. These calculatons include consideration of competing risks of death from all other causes. The program also generates a probability frequency distribution of the expected number of cancers in any specified cohort resulting from a given radiation dose. The methods may be applied to any specified population and dose scenario

  9. Kinetic features of radiation-induced electric conductivity in polymers

    Dependence of radiation-induced electric conductivity (EC) of certain polymers on the time of irradiation by accelerated electrons (75 keV in the range of dose rate D = 20-500 Gy/s) with varying irradiation temperature, dose rate and electric field intensity has been studied. Existence of three stages of EC increase has been revealed in all the polymers studied: 'instant' (time of increment t << 1 s), 'fast' (t = 1-10 s) and 'decelerated' (t = 10-1000 s). It is shown that kinetic regularities of polymer EC can not be coordinated in the framework of the model of multiple capture of charges. The conclusion is made on determining role of molecular mobility in transfer of charge carriers generated by ionizing radiation. 12 refs., 4 figs., 1 tab

  10. X-radiation-induced chromosome breakage in retinoblastoma lymphocytes

    The authors have examined the spontaneous and X-radiation-induced chromosomal damage in normal humans and in patients with retinoblastoma using the BudR-Giemsa technique in lymphocytes cultured for 48 h. 9 sporadic unilateral non-hereditary cases, 11 hereditary cases and 20 healthy individuals were studied simultaneously. No difference in the spontaneous frequency of chromatid and chromosome aberrations was observed between patients and controls. The results suggest that: (a) There is no relationship between spontaneous chromosome fragility and retinoblastoma. (b) Sporadic unilateral non-hereditary retinoblastoma has normal chromosome sensitivity to X-irradiation. (c) Some hereditary cases of retinoblastoma are sensitive to X-rays while others behave like normals. A mutation or a submicroscopic deletion at a DNA repair locus which is independent of the retinoblastoma gene may cause this radiosensitivity. (Auth.)

  11. Proton spectroscopy of radiation-induced injury to the brain

    This paper reports on the role of hydrogen MR spectroscopy (HMRS) in differentiating radiation-injured brain from normal brain and neoplasm, the authors performed HMRS on five cat brains with iatrogenically produced radiation injury. Reductions in N-acetyl aspartate (NAA/choline, and NAA/creatine-phosphocreatine (CR)) resonances were demonstrated in voxels from the five irradiated hemispheres compared with normal hemispheres (P < .01). NAA/CR ratios below 1.21 were always associated with radiation injury; ratios above 1.30 demarcated normal hemispheres. Large unassigned amino acid resonances from 2.0 to 2.5 ppm were also present. Results of autopsy examination confirmed radiation-induced white matter injury. Using NAA/CR ratios, one can separate normal brain from radiation-injured brain. Differentiating residual tumor from radiation-injured and normal brain may be possible with HMRS

  12. Invertase immobilization onto radiation-induced graft copolymerized polyethylene pellets

    The graft polymer poly(ethylene-g-acrylic acid) (LDPE-g-AA) was prepared by radiation-induced graft copolymerization of acrylic acid onto low density polyethylene (LDPE) pellets, and characterized by infrared photoacoustic spectroscopy and scanning electron microscopy (SEM). The presence of the grafted poly(acrylic acid) (PAA) was established. Invertase was immobilized onto the graft polymer and the thermodynamic parameters of the souble and immobilized enzyme were determined. The Michaelis constant, Km, and the maximum reaction velocity, Vmax, were determined for the free and the immobilized invertase. The Michaelis constant, Km was larger for the immobilized invertase than for the free enzyme, whereas Vmax, was smaller for the immobilized invertase. The thermal stability of the immobilized invertase was higher than that of the free enzyme. (Author)

  13. Genomic alterations in radiation-induced murine acute myeloid leukemias

    High-dose radiation induces acute myeloid leukemia (AML) in C3H mice, most of which have a high frequent hemizygous deletion around the D2Mit15 marker on the interstitially deleted region of chromosome 2. This region involves PU.1 (Sfpi-1), which is a critical candidate gene for initiation of mouse leukemogenesis. To identify other genes contributing to leukemogenesis with PU.1, we analyzed chromosomal aberrations and changes of expression in 18 AML-related genes in 39 AMLs. Array CGH analysis revealed that 35 out of 39 AMLs had hemizygous deletions of chromosome 2, and recurrent aberrations on chromosomes 4, 6, 8, 10, 11, 12, 15, and 18. Expressions of 18 AML-related genes, within the altered chromosome regions detected by array CGH were analyzed by using RT-PCR and/or real-time PCR. Although Wnt5b, Wnt16, G-CSFR, M-CSFR, SCL/Tal-1 and GATA1 genes were down-regulated, the c-myc gene was, on the contrary, up-regulated. Expression levels of two genes, Rasgrp1 and Wt1, within the deleted region of chromosome 2 correlated with the loss of one of two alleles, although the expression of PU.1 showed an inverse correlation. In addition, the expression level of PU.1 appeared to be higher with a coincidental missense point mutation in DNA-binding domain of PU.1 in the remaining allele, suggesting a feedback transcription control on PU.1. Such an autoregulation might be relevant to the fact that PU.1 haploinsufficiency per se triggers radiation-induced AML. Together with the detection of chromosomal aberrations, these findings provide useful clues to identify cooperative genes that are responsible for molecular pathogenesis of AMLs induced by low-dose-rate radiation exposure. (author)

  14. Genetic analysis of radiation-induced mouse thymic lymphomas

    Mouse thymic lymphomas are one of the classic models of radiation-induced malignancies, and the model has been used for the study of genes involved in carcinogenesis. ras oncogenes are the first isolate which undergoes mutations in 10 to 30 % of lymphomas, and p16INK4a and p19ARF in the INK4a-ARF locus are also frequently inactivated. In our previous study, the inactivation of Ikaros, a key regurator of lymphoid system, was found in those lymphomas, and it was suggested that there are other responsible genes yet to be discovered. On the other hand, genetic predisposition to radiation-induced lymphoma often differs in different strains, and this reflects the presence of low penetrance genes that can modify the impact of a given mutation. Little study of such modifiers or susceptibility genes has been performed, either. Recent availability of databases on mouse genome information and the power of mouse genetic system underline usefulness of the lymphoma model in search for novel genes involved, which may provide clues to molecular mechanisms of development of the radiogenic lymphoma and also genes involved in human lymphomas and other malignancies. Accordingly, we have carried out positional cloning for the two different types of tumor-related genes. In this symposium, our current progress is presented that includes genetic mapping of susceptibility/ resistance loci on mouse chromosomes 4, 5 and 19, and also functional analysis of a novel tumor suppressor gene, Rit1/Bcl11b, that has been isolated from allelic loss (LOH) mapping and sequence analysis for γ -ray induced mouse thymic lymphomas

  15. Radiation-induced brachial plexus neuropathy in breast cancer patients

    Olsen, N.K.; Pfeiffer, P.; Mondrup, K.; Rose, C. (Odense Univ. Hospital (Denmark). Dept. of Neurology Odense Univ. Hospital (Denmark). Dept. of Clinical Neurophysiology Odense Univ. Hospital (Denmark). Dept. of Oncology R)

    1990-01-01

    The incidence and latency period of radiation-induced brachial plexopathy (RBP) were assessed in 79 breast cancer patients by a neurological follow-up examination at least 60 months (range 67-130 months) after the primary treatment. All patients were treated primarily with simple mastectomy, axillary nodal sampling and radiotherapy (RT). Postoperatively, pre- and postmenopausal patients were randomly allocated chemotherapy for antiestrogen treatment. All patients were recurrence-free at time of examination. Clinically, 35% (25-47%) of the patients had RBP; 19% (11-29%) had definite RBP, i.e. were physically disabled, and 16% (9-26%) had probable RBP. Fifty percent (31-69%) had affection of the entire plexus, 18% (7-35%) of the upper trunk only, and 4% (1-18%) of the lower trunk. In 28% (14-48%) of cases assessment of a definite level was not possible. RBP was more common after radiotherapy and chemotherapy (42%) than after radiotherapy alone (26%) but the difference was not statistically significant (p = 0.10). The incidence of definite RBP was significantly higher in the younger age group (p = 0.02). This could be due to more extensive axillary surgery but also to the fact that chemotherapy was given to most premenopausal patients. In most patients with RBP the symptoms began during or immediately after radiotherapy, and were thus without significant latency. Chemotherapy might enhance the radiation-induced effect on nerve tissue, thus diminishing the latency period. Lymphedema was present in 22% (14-32%), especially in the older patients, and not associated with the development of RBP. In conclusion, the damaging effect of RT on peripheral nerve tissue was documented. Since no successful treatment is available, restricted use of RT to the brachial plexus is warranted, especially when administered concomitantly with cytotoxic therapy. (orig.).

  16. Radiation-induced brachial plexus neuropathy in breast cancer patients

    The incidence and latency period of radiation-induced brachial plexopathy (RBP) were assessed in 79 breast cancer patients by a neurological follow-up examination at least 60 months (range 67-130 months) after the primary treatment. All patients were treated primarily with simple mastectomy, axillary nodal sampling and radiotherapy (RT). Postoperatively, pre- and postmenopausal patients were randomly allocated chemotherapy for antiestrogen treatment. All patients were recurrence-free at time of examination. Clinically, 35% (25-47%) of the patients had RBP; 19% (11-29%) had definite RBP, i.e. were physically disabled, and 16% (9-26%) had probable RBP. Fifty percent (31-69%) had affection of the entire plexus, 18% (7-35%) of the upper trunk only, and 4% (1-18%) of the lower trunk. In 28% (14-48%) of cases assessment of a definite level was not possible. RBP was more common after radiotherapy and chemotherapy (42%) than after radiotherapy alone (26%) but the difference was not statistically significant (p = 0.10). The incidence of definite RBP was significantly higher in the younger age group (p = 0.02). This could be due to more extensive axillary surgery but also to the fact that chemotherapy was given to most premenopausal patients. In most patients with RBP the symptoms began during or immediately after radiotherapy, and were thus without significant latency. Chemotherapy might enhance the radiation-induced effect on nerve tissue, thus diminishing the latency period. Lymphedema was present in 22% (14-32%), especially in the older patients, and not associated with the development of RBP. In conclusion, the damaging effect of RT on peripheral nerve tissue was documented. Since no successful treatment is available, restricted use of RT to the brachial plexus is warranted, especially when administered concomitantly with cytotoxic therapy. (orig.)

  17. Radiation-induced thyroid cancer after radiotherapy for childhood cancer

    Jiravova, M. [Department of Nuclear Medicine and Endocrinology, Faculty Hospital Motol, Uk, Prague (Czech Republic)

    2012-07-01

    Full text of the publication follows: The thyroid gland in children is among the most sensitive organs to the carcinogenic effects of ionizing radiation, and very young children are at especially high risk. Due to extreme sensitivity of the thyroid gland in children, there is a risk of radiation - induced thyroid cancer even when the thyroid gland is outside the irradiated field. Increased incidence of thyroid cancer has been noted following radiotherapy not only for childhood Hodgkin disease (majority of observed patients), but also for non-Hodgkin lymphoma, neuroblastoma, Wilms tumor, acute lymphocytic leukemia and tumors of the central nervous system also. Radiation-induced tumors begin to appear 5-10 years after irradiation and excess risk persists for decades, perhaps for the remainder of life. The incidence of thyroid cancer is two- to threefold higher among females than males. Most of the thyroid cancers that occur in association with irradiation are of the papillary type, for which the cure rate is high if tumors are detected early. Our Department in co-operation with Department of Children Hematology and Oncology Charles University Second Faculty of Medicine and Faculty Hospital Motol monitors patients after therapy for cancer in childhood for the long term period. The monitoring is focused on detection of thyroid disorders that occur as last consequences of oncology therapy, especially early detection of nodular changes in thyroid gland and thyroid carcinogenesis. The survey presents two patients observed in our department that were diagnosed with the papillary thyroid carcinoma which occurred 15 and more years after radiotherapy for childhood cancer. After total thyroidectomy they underwent therapy with radioiodine. After radiotherapy it is necessary to pursue a long-term following and assure interdisciplinary co-operation which enables early detection of last consequences of radiotherapy, especially the most serious ones as secondary carcinogenesis

  18. Radiation-induced leukemia: Comparative studies in mouse and man

    Haas, M.

    1991-01-01

    We now have a clear understanding of the mechanism by which radiation-induced (T-cell) leukemia occurs. In irradiated mice (radiation-induced thymic leukemia) and in man (acute lymphoblastic T-cell leukemia, T-ALL) the mechanism of leukemogenesis is surprisingly similar. Expressed in the most elementary terms, T-cell leukemia occurs when T-cell differentiation is inhibited by a mutation, and pre-T cells attempt but fail to differentiate in the thymus. Instead of leaving the thymus for the periphery as functional T-cells they continue to proliferate in the thymus. The proliferating pre- (pro-) T-cells constitute the (early) acute T-cell leukemia (A-TCL). This model for the mechanism of T-cell leukemogenesis accounts for all the properties of both murine and human A-TCL. Important support for the model has recently come from work by Ilan Kirsch and others, who have shown that mutations/deletions in the genes SCL (TAL), SIL, and LCK constitute primary events in the development of T-ALL, by inhibiting differentiation of thymic pre- (pro-) T-cells. This mechanism of T-cell leukemogenesis brings several specific questions into focus: How do early A-TCL cells progress to become potently tumorigenic and poorly treatable Is it feasible to genetically suppress early and/or progressed A-TCL cells What is the mechanism by which the differentiation-inhibited (leukemic) pre-T cells proliferate During the first grant year we have worked on aspects of all three questions.

  19. Radiation-induced crosslinking and grafting reactions in polyethylene

    This dissertation is concerned with three aspects of the crosslinking and grafting reactions induced by ionizing radiation on polyethylenes. One is the effect of trace inert fillers on the radiation-induced crosslinking of polyethylene. Experiments were performed with silica filled samples of low-density polyethylene subjected to 5 and 10 Mrad doses of gammas and electrons. Contrary to Goriyendo's results the insoluble fraction was found to be independent of SiO2 concentrations up to 0.5% by volume of both a finely divided and coarse filler. Another unexplained phenomenon is the ability of acid to enhance the radiation-induced grafting of styrene to polyethylene. Experiments were performed using polyethylene films immersed in styrene-methanol solutions both with and without acid and oxygen. The results show the gamma-induced grafting rate is enhanced by the presence of acid even in O2-free systems, despite the fact that the acid does not permeate the film. To better understand the crystalline region of polyethylene, ESR measurements at low power levels were made on sngle crystals of n-eicosane (n-C20H42) irradiated with gammas at 770K. The relative yields and the migration and decay mechanisms of the radicals suggest that the fracture of C-H bonds in irradiated eicosane favors the yield of the interior secondary alkyl radical far more than is to be expected from a radom fracture pattern. The results also demonstrate that the intramolecular migration of the alkyl radical site is more rapid than intermolcular migration. An ionic mechanism is proposed for the production of the alkyl free radicals in irradiated polyethylene and all other solid linear alkanes. The non-random fracture pattern of the C-H bonds in alkanes is explained in terms of random ionization and positive hole migration to the energetically favored interior position, followed by the ionic processes of the Weiss mechanism

  20. Radiation-induced thyroid cancer after radiotherapy for childhood cancer

    Full text of the publication follows: The thyroid gland in children is among the most sensitive organs to the carcinogenic effects of ionizing radiation, and very young children are at especially high risk. Due to extreme sensitivity of the thyroid gland in children, there is a risk of radiation - induced thyroid cancer even when the thyroid gland is outside the irradiated field. Increased incidence of thyroid cancer has been noted following radiotherapy not only for childhood Hodgkin disease (majority of observed patients), but also for non-Hodgkin lymphoma, neuroblastoma, Wilms tumor, acute lymphocytic leukemia and tumors of the central nervous system also. Radiation-induced tumors begin to appear 5-10 years after irradiation and excess risk persists for decades, perhaps for the remainder of life. The incidence of thyroid cancer is two- to threefold higher among females than males. Most of the thyroid cancers that occur in association with irradiation are of the papillary type, for which the cure rate is high if tumors are detected early. Our Department in co-operation with Department of Children Hematology and Oncology Charles University Second Faculty of Medicine and Faculty Hospital Motol monitors patients after therapy for cancer in childhood for the long term period. The monitoring is focused on detection of thyroid disorders that occur as last consequences of oncology therapy, especially early detection of nodular changes in thyroid gland and thyroid carcinogenesis. The survey presents two patients observed in our department that were diagnosed with the papillary thyroid carcinoma which occurred 15 and more years after radiotherapy for childhood cancer. After total thyroidectomy they underwent therapy with radioiodine. After radiotherapy it is necessary to pursue a long-term following and assure interdisciplinary co-operation which enables early detection of last consequences of radiotherapy, especially the most serious ones as secondary carcinogenesis

  1. Defense mechanisms against radiation induced teratogenic damage in mice

    Experimental studies with mice have established that fetuses at midgestational stage are highly susceptible to malformation at high, but not low, doses of radiation. When DNA damage is produced by a small amount of radiation, it is efficiently eliminated by DNA repair. However, DNA repair is not perfect. There must be defense mechanisms other than DNA repair. In order to elucidate the essential role of p53 gene in apoptotic tissue repair, we compared the incidence of radiation-induced malformations and deaths (deaths after day 10) in wild-type p53 (+/+) mice and null p53 (-/-) mice. For p53 (+/+) mice, an X-ray dose of 2 Gy given at a high dose-rate (450 mGy/min) to fetuses at 9.5 days of gestation was highly lethal and considerably teratogenic whereas it was only slightly lethal but highly teratogenic for p53 (-/-) fetuses. This reciprocal relationship of radiosensitivity to malformations and deaths supports the notion that fetal tissues have a p53 -dependent idguardianln of the tissue that aborts cells bearing radiation-induced teratogenic DNA damage. When an equal dose of 2 Gy given at a 400-fold lower dose-rate (1.2 mGy/min), this dose became not teratogenic for p53 (+/+) fetuses exhibiting p53 -dependent apoptosis, whereas this dose remained teratogenic for p53 (-/-) fetuses unable to carry out apoptosis. Furthermore, when the dose was divided into two equal dose fractions (1+1 Gy) at high dose rate, separated by 24 hours, the incidences of malformations were equal with control level for p53 (+/+), but higher for p53 (-/-) mice. Hence, complete elimination of teratogenic damage from irradiated tissues requires a concerted cooperation of two mechanisms; proficient DNA repair and p53-dependent apoptotic tissue repair

  2. Radiation induced corrosion of copper for spent nuclear fuel storage

    The long term safety of repositories for radioactive waste is one of the main concerns for countries utilizing nuclear power. The integrity of engineered and natural barriers in such repositories must be carefully evaluated in order to minimize the release of radionuclides to the biosphere. One of the most developed concepts of long term storage of spent nuclear fuel is the Swedish KBS-3 method. According to this method, the spent fuel will be sealed inside copper canisters surrounded by bentonite clay and placed 500 m down in stable bedrock. Despite the importance of the process of radiation induced corrosion of copper, relatively few studies have been reported. In this work the effect of the total gamma dose on radiation induced corrosion of copper in anoxic pure water has been studied experimentally. Copper samples submerged in water were exposed to a series of total doses using three different dose rates. Unirradiated samples were used as reference samples throughout. The copper surfaces were examined qualitatively using IRAS and XPS and quantitatively using cathodic reduction. The concentration of copper in solution after irradiation was measured using ICP-AES. The influence of aqueous radiation chemistry on the corrosion process was evaluated based on numerical simulations. The experiments show that the dissolution as well as the oxide layer thickness increase upon radiation. Interestingly, the evaluation using numerical simulations indicates that aqueous radiation chemistry is not the only process driving the corrosion of copper in these systems. - Highlights: • Copper cubes were exposed to gamma radiation in anoxic pure water. • The dissolution of copper increases with increasing absorbed total dose. • The oxide layer formed consists mainly of cuprite. • Numerical simulations of the irradiation experiments were performed. • There is a large discrepancy between numerical simulations and experimental results

  3. [Radiation-induced cancers: state of the art in 1997].

    Cosset, J M

    1997-01-01

    Scientists now have available a large amount of data dealing with radiation-induced neoplasms. These data went back to anecdotal observations which were made in the very first years of utilization of X-rays and radioactive elements. In fact, it is essentially the strict follow-up of the Japanese populations irradiated by the Hiroshima and Nagasaki bombing which allowed a more precise evaluation of the carcinogenicity of ionizing radiations. Further refinements came from therapeutical irradiations: it is now possible to study large cohorts of patients given well-known doses in well-defined volumes and followed for more than 20 years. Last but not least, a significant increase in the incidence and mortality of thyroid cancer has been detected in children contaminated by iodine radioisotopes after the Tchernobyl accident. Recently, some data suggested the emergence of "clusters" of leukemias close to some nuclear facilities, but this question remains highly polemical, both in France and in the UK. Other questions are still waiting for a precise answer; of course, the extrapolation of our available data to very low doses delivered at very low dose rates, but also the carcinogenic risk at high doses. For these "high" doses (about 30 to 70 Gy), a competition between mutagenesis and cell killing was expected, so that these dose levels were expected to be less carcinogenic than lower (a few sieverts) doses. Actually, recent data suggest that the carcinogenic risk goes on increasing up to relatively important doses. In addition, carcinogenic factors, such as tabacco, anticancer chemotherapy and individual susceptibility, are found more and more to be closely intricated with ionizing radiation in the genesis of a given cancer. Even if a number of questions are still pending, the already available data allow specialists, both in medicine and radioprotection, to edict strict rules which can be reasonably expected to have significantly reduced the risk of radiation-induced

  4. Radiation induces aerobic glycolysis through reactive oxygen species

    Background and purpose: Although radiation induced reoxygenation has been thought to increase radiosensitivity, we have shown that its associated oxidative stress can have radioprotective effects, including stabilization of the transcription factor hypoxia inducible factor 1 (HIF-1). HIF-1 is known to regulate many of the glycolytic enzymes, thereby promoting aerobic glycolysis, which is known to promote treatment resistance. Thus, we hypothesized that reoxygenation after radiation would increase glycolysis. We previously showed that blockade of oxidative stress using a superoxide dismutase (SOD) mimic during reoxygenation can downregulate HIF-1 activity. Here we tested whether concurrent use of this drug with radiotherapy would reduce the switch to a glycolytic phenotype. Materials and methods: 40 mice with skin fold window chambers implanted with 4T1 mammary carcinomas were randomized into (1) no treatment, (2) radiation alone, (3) SOD mimic alone, and (4) SOD mimic with concurrent radiation. All mice were imaged on the ninth day following tumor implantation (30 h following radiation treatment) following injection of a fluorescent glucose analog, 2-[N-(7-nitrobenz-2-oxa-1,3-diaxol-4-yl)amino]-2-deoxyglucose (2-NBDG). Hemoglobin saturation was measured by using hyperspectral imaging to quantify oxygenation state. Results: Mice treated with radiation showed significantly higher 2-NBDG fluorescence compared to controls (p = 0.007). Hemoglobin saturation analysis demonstrated reoxygenation following radiation, coinciding with the observed increase in glycolysis. The concurrent use of the SOD mimic with radiation demonstrated a significant reduction in 2-NBDG fluorescence compared to effects seen after radiation alone, while having no effect on reoxygenation. Conclusions: Radiation induces an increase in tumor glucose demand approximately 30 h following therapy during reoxygenation. The use of an SOD mimic can prevent the increase in aerobic glycolysis when used

  5. Radiation-induced cancers: a 1997 state of the art

    Scientists now have available a large amount of data dealing whit radiation-induced neoplasms. These data went back to anecdotal observations which were made in the very first years of utilization of X-rays and radioactive elements. In fact, it is essentially the strict follow-up of the Japanese populations irradiated by the Hiroshima and Nagasaki bombing which allowed a more precise evaluation of the carcinogenicity of ionizing radiations. Further refinements came from therapeutical irradiations: it is now possible to study large cohorts of patient given well-known doses in well defined volumes and followed for more than 20 years. Last but not least, a significant increase in the incidence and mortality of thyroid cancer has been detected in children contaminated by iodine radioisotopes after the Tchernobyl accident. Recently, some data suggested the emergence of 'clusters' of leukemias close to some nuclear facilities, but this question remains highly polemical, both in France and in the UK. Other questions are still waiting for a precise answer; of course, the extrapolation of our available data to very low does delivered at very low dose rates, but also the carcinogenic risk at high doses. For these 'high' doses (about 30 to 70 Gy), a competition between mutagenesis and cell killing was expected, so that these dose levels were expected to be less carcinogenic than lower (a few sieverts) doses. Actually, recent data suggest that the carcinogenic risk goes on increasing up to relatively important doses. In addition, carcinogenic factors, such as tobacco, anticancer chemotherapy and individual susceptibility, are found more and more to be closely intricated with ionizing radiation in the genesis of a given cancer. Even if a number of questions are still pending, the already available data allow specialists, both medicine and radioprotection, to edict strict rules which can be reasonable expected to have significantly reduced the risk of radiation-induced neoplasms

  6. Role of Oxidative Damage in Radiation-Induced Bone Loss

    Schreurs, Ann-Sofie; Alwood, Joshua S.; Limoli, Charles L.; Globus, Ruth K.

    2014-01-01

    used an array of countermeasures (Antioxidant diets and injections) to prevent the radiation-induced bone loss, although these did not prevent bone loss, analysis is ongoing to determine if these countermeasure protected radiation-induced damage to other tissues.

  7. A case of probable radiation-induced carcinoma of the lung

    Ichihashi, Takumi; Yamamura, Kouzen [Tsuruga City Hospital, Fukui (Japan); Kobayashi, Hiroaki

    1995-10-01

    A 43-year-old non-smoker female had received radiation therapy ({sup 60}Cobalt) after standard radical mastectomy for breast cancer. When she was 62 years old, a chest x-ray film from her regular health check-up showed an abnormal shadow at the right upper lobe in the same area as the irradiated field, as was indicated by skin telangiectasia. Three years later, it had grown and become about 2 cm in size. Computed tomography scan revealed a subpleural lung tumor and thickening of the parietal pleura near the tumor. Lung cancer was diagnosed (cT{sub 3}N{sub 0}M{sub 0} IIIA) by bronchofiberscopic brushing cytology. Posterolateral thoracotomy showed no pleural adhesion. Right upper lobectomy was done. The tumor was well differentiated papillary adenocarcinoma of the lung (pT{sub 1}N{sub 0}M{sub 0} I) on histological examination. According to the criteria of highly probable radiation-induced malignant tumors proposed by Sakai et al., a second malignancy histologically different from the first one must arise from another organ within the radiation field and the latent period must be more than 5 years. In our view, this case is generally consistent with the criteria. (author).

  8. Mechanisms of radiation-induced thymic lymphomagenesis. For molecular biology approach

    This review described findings obtained by the analysis of prelymphoma cells with use of cell sorting and cell transplant in thymus and by marginal dilution for frequency of prelymphoma cells in thymocyte population of irradiated mice. A comparison was made between analytical results of reconstruction of T-cell receptor genes and findings on various changes accompanying carcinogenesis to get an experimental design to estimate the stages for those changes (abnormalities in p53 tumor-suppressing genes and in chromosomes) occurring in the cause of carcinogenesis. As a result, a hypothesis was presented that radiation induces the gene expression which does not occur under normal conditions to result in the genetic instability to lead to carcinogenesis. The author documented these in following chapters. Properties of pre-lymphoma cells. Frequency of prelymphoma cells in population of TL-2 positive thymocytes in irradiated individual mice. T-cell differentiation and cancer initiation. Analysis of p53 tumor-suppressing gene mutant. Analysis of chromosome aberrations. Reconstruction of gamma TCR genes and a comparison of stages of generation of chromosome aberration. cDNA subtraction. (K.H.)

  9. Molecular genetic analysis of regions of the murine genome associated with radiation-induced mutations

    The authors are exploiting the large array of radiation-induced mutations to develop both detailed molecular and functional maps of selected small model regions (as opposed to specific genes) within the mouse genome. Through the integrated use of recombinant DNA technology and classical genetic and cytogenetic analysis, they hope to relate the structure and function of these regions to the study of both normal and abnormal mammalian development. Over the years, the germ-line mutagenesis program has generated a valuable array of induced mutations at several specific loci scattered throughout the murine genome. Many of these mutations are multilocus deletions of chromosomal DNA. Genetic analysis of these types of lesions has detected passenger mutations of wide-ranging effect and severity, and has generated gross functional maps of entire chromosomal regions. They have initiated a program to expand the molecular analysis of these types of deletion mutations. This program exploits the deletion mutations and other chromosomal rearrangements to obtain molecular clones of wild-type DNA that map to regions absent in mutants carrying the deletions. These clones will then be used to correlate the resultant molecular/physical map of the chromosomal region with the genetic/functional map in both mutant and wild-type individuals. Such correlations are essential to a strategy for identifying as many of the genes as possible in a particular region of the genome and for ascertaining their role(s) in the normal development of the mouse

  10. Clinical and electrodiagnostic findings in breast cancer patients with radiation-induced brachial plexus neuropathy

    The clinical and neurophysiological characteristics of radiation-induced brachial plexopathy (RBP) were assessed in 79 breast cancer patients without signs of recurrent disease at least 60 months after radiotherapy (RT). Clinically, 35% (95% confidence limits: 25-47%) had RBP. Fifty percent (31-69%) had affection of the entire plexus, 18% (7-36%) of the upper trunk only, and 4% (1-18%) of the lower trunk. In 28% (14-48%), assessment of a definite level was not possible. In most, symptoms began during or immediately after RT, thus being without significant latency. Numbness or paresthesias (71%, 52-86%) and pain (43%, 25-62%) were the most prominent symptoms, while the most prominent objective signs were decreased or absent muscle stretch reflexes (93%, 77-99%) closely followed by sensory loss (82%, 64-93%) and weakness (71%, 52-86%). Neurophysiological investigations were carried out in 46 patients (58%). The most frequent abnormalities in patients with RBP were signs of chronic partial denervation with increased mean duration of individual motor unit potentials, and decreased amplitude of compound muscle and sensory action potentials. Nerve conduction velocities were normal. (author)