Long-term Effects Of Radiation Research Articles

Short- and long-term physiological responses of grapevine leaves to UV-B radiation

The present study aimed at evaluating the short- and long-term effects of UV-B radiation on leaves of grapevine Vitis vinifera (cv. Tempranillo). Grapevine fruit-bearing cuttings were exposed to two doses of supplemental biologically effective UV-B radiation (UV-BBE) under glasshouse-controlled conditions: 5.98 and 9.66kJm−2d−1. The treatments were applied either for 20d (from mid-veraison to ripeness) or 75d (from fruit set to ripeness). A 0kJm−2d−1 UV-B treatment was included as control. The main effects of UV-B were observed after the short-term exposure (20d) to 9.66kJm−2d−1. Significant decreases in net photosynthesis, stomatal conductance, sub-stomatal CO2 concentration, the actual photosystem II (PSII) efficiency, total soluble proteins and de-epoxidation state of the VAZ cycle were observed, whereas the activities of several antioxidant enzymes increased significantly. UV-B did not markedly affect dark respiration, photorespiration, the maximum potential PSII efficiency (Fv/Fm), non-photochemical quenching (NPQ), as well as the intrinsic PSII efficiency. However, after 75d of exposure to 5.98and 9.66kJm−2d−1 UV-B most photosynthetic and biochemical variables were unaffected and there were no sign of oxidative damage in leaves. The results suggest a high long-term acclimation capacity of grapevine to high UV-B levels, associated with a high accumulation of UV-B absorbing compounds in leaves, whereas plants seemed to be tolerant to moderate doses of UV-B.

250 Long-term effects of exposures at oak ridge national laboratory

We examine mortality in a cohort of workers at the Oak Ridge National Laboratory (ORNL), a US Department of Energy research and development facility. The last mortality follow-up of this...

The effects of CX3CR1 deficiency and irradiation on the homing of monocyte-derived cell populations in the mouse eye.

This study examined whether CX3CR1 deficiency altered monocytic cell replenishment dynamics in ocular tissues in the context of radiation chimeras. Long-term effects of irradiation and effects of sublethal irradiation on ocular macrophages were also assessed. Bone marrow from BALB/c Cx 3 cr1 +/gfp or Cx 3 cr1 gfp/gfp mice was used to reconstitute full body irradiated WT mice and donor cell densities in the uveal tract were compared at 4 and 8 weeks post-transplantation. BALB/c and C57BL/6J chimeric mice were examined at 6 months of age to determine strain-related differences in microglial replenishment and radiation sensitivity. A separate cohort of mice were sublethally irradiated (5.5 Gy) and retinal tissue assessed 8 and 12 weeks later. CX3CR1 deficiency altered the early replenishment of monocytes in the posterior iris but not in the iris stroma, choroid or retina. In six month old chimeric mice, there were significantly higher GFP+ cell densities in the uveal tract when compared to non-irradiated 8-12 week old Cx 3 cr1 +/gfp mice. Additionally, MHC Class II expression was upregulated on hyalocytes and GFP+ cells in the peripheral retina and the repopulation of microglia appeared to be more rapid in C57BL/6J mice compared to BALB/c mice. Transient expression of MHC Class II was observed on retinal vasculature in sublethally irradiated mice. These data indicate CX3CR1-deficiency only slightly alters monocyte-derived cell replenishment in the murine uveal tract. Lethal irradiation leads to long-term increase in monocytic cell density in the uveal tract and retinal microglial activation, possibly as a sequelae to local irradiation induced injury. Microglial replenishment in this model appears to be strain dependent.

The Role of Optical Radiations in Skin Cancer

Purpose. Electromagnetic radiation with wavelength in the range 100 nm to 1 mm is known as optical radiation and includes ultraviolet radiation, the visible spectrum, and infrared radiation. The deleterious short- and long-term biological effects of ultraviolet radiation, including melanoma and other skin cancers, are well recognized. Infrared radiation may also have damaging biological effects. Methods. The objective of this review was to assess the literature over the last 15 years and to summarize correlations between exposure to optical radiation and the risk of melanoma and other cancers. Results. There is a clear correlation between exposure to UV radiation and the development of skin cancer. Most importantly, a strong association between artificial UV radiation exposure, for example, tanning devices, and the risk of melanoma and squamous cell carcinoma has been clearly demonstrated. There is no clear evidence that exposure to IR and laser radiation may increase the risk of skin cancer, although negative health effects have been observed. Conclusions. Preventative strategies that involve provision of public information highlighting the risks associated with exposure to sunlight remain important. In addition, precautionary measures that discourage exposure to tanning appliances are required, as is legislation to prevent their use during childhood.

Abstract 4797: The antioxidation microsphere flow cytometer assay.

Abstract Increased production of reactive oxygen species is a feature of most, if not all, human disease, including cardiovascular disease and cancer. Dietary antioxidants may be especially important in protecting against human diseases associated with free radical damage to cellular DNA, lipids, and proteins. Yet, present data are not sufficient to quantify micronutrient requirements needed to protect against oxidative damage. The antioxidant roles of many food constituents, including herbs and spices, have not been clarified. The AMFC assay measures the oxidation of R-Phycoerythrin attached to microspheres via a protein coupling linker. A 25mM stock solution of ABTS.+ [2,2’-Azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid) free radical], prepared during a 12 hour, 4 °C incubation with potassium persulfate to cause removal of one electron generating a metastable ABTS. This stock solution was diluted to 100μM in 150μl, which resulted in 80% quenching of 15μl of 104 PE microspheres. The antioxidant effects were measured by first incubating 50μl the 80 % quenching ABTS.+ with 100μl portions of serial diluted antioxidants for 30 min. at 22 °C to determine the antioxidants neutralize the ABTS.+. Subsequently, 15μl of PE-tagged microspheres were added to each sample and incubated one hour at 22 °C. The peak fluorescent channel number was determined for 5,000 microspheres. The typical percentage protection by the antioxidant standard at 500 ng/ml for Trolox (water soluble Vitamin E derivative) was 8, while 500 ng/ml of Vitamin C restored 78% The range of 500-5,000 ng/ml showed the protective effects of Trolox and Vitamin C remained constant. On the average, equivalent percentage protection for both the hydrophilic and lipid soluble fractions of 14 spices (courtesy of McCormick Science Institute) was not achieved until the 20-50 μg/ml concentration of the spices with Turmeric, Cinnamon, Oregano and Cloves, showing the highest antioxidant protection. Interestingly, Rosemary, Sage, Thyme and Turmeric revealed a significant reduction in antioxidant activity at 200 μg/ml. These are still significant antioxidant levels that show a secondary reason besides flavoring to use spices for achieving clinically important antioxidant activity. The AMFC assay is very sensitive to the effects of oxidants, functions under physiological conditions, requires little sample and allows application to the study of serum samples. Thus, one may monitor antioxidant activity in healthy volunteers taking compounds to boost the antioxidant activity to offset the long-term effects of oxidative radiation and chemotherapy. Citation Format: Jerry T. Thornthwaite, Hare R. Shah. The antioxidation microsphere flow cytometer assay. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4797. doi:10.1158/1538-7445.AM2013-4797 Note: This abstract was not presented at the AACR Annual Meeting 2013 because the presenter was unable to attend.

Radiation effects on composites for long-duration lunar habitats

Fiber-reinforced composites are of great interest to NASA for deep-space habitation missions due to the specific strength, modulus and potential radiation shielding properties. However, the durability of these materials on long-duration missions has not been evaluated. Few studies have been conducted on the radiation effects of fiber-reinforced composites in space and even fewer have been conducted with high-energy protons, which replicate portions of the deep-space radiation environment. Furthermore, previous studies of carbon fiber-reinforced composites focused on pure epoxy composites, and aerospace composites in use today include toughening agents to increase the toughness of the material. These toughening agents are typically either rubber particles or thermoplastics, known to be susceptible to ionizing radiation, and could affect the overall composite durability when exposed to high-energy protons. Thus, NASA has undertaken a study to understand the long-term radiation effects on one such potential composite for use in deep-space habitats (boron fiber, carbon fiber and semi-toughened epoxy). Samples were irradiated with 200 MeV protons in air to different doses and evaluated via tensile tests, differential scanning calorimetry, Fourier transform infrared spectroscopy and scanning electron microscopy. The results showed evidence of a weakened matrix due to scission effects and interfacial failure as a result of resin debonding from the boron fibers.

Short‐term Histopathology Effects of Gamma Knife Radiosurgery on a Vestibular Schwannoma

Radiosurgery is a popular management strategy for vestibular schwannoma (VS), with approximately one-third of patients being treated with this modality today. The goal in radiosurgery is to halt tumor growth. Tumor growth control rates range from 70% to 97%.1 The direct effect of radiation on tumor cells is DNA damage, triggering apoptosis. Immediate or delayed cell death may occur, depending on whether the cell is actively dividing. Because of the benign and slow-growing nature of VS, this effect may not account for the cumulative effect of radiation. Radiation also induces vascular damage, leading to ischemia and cell death. In a series of 5 patients who had microsurgical resection after stereotactic radiation, immunohistochemistry using antibodies directed against the vascular endothelial markers, factor VIII and CD34, demonstrated decreased staining with increasing isodoses and no staining at the tumor center.1 Damage to the vascular endothelial cells occurs 2 to 4 months after radiation. Here, we show results of a histological/immunohistochemical investigation of a VS tumor 5 months following treatment with radiosurgery. While prior studies have shown long-term radiation effects, this case represents a unique view into the short-term biological effects of schwannoma gamma knife irradiation, which may provide clues to radiation failure, tumor regrowth, and potential strategies for tumor control.

Competing Roads to Larynx Preservation

Combined modality research in laryngeal cancer has focused on the dual goals of increased survival and functional organ preservation. Competing strategies consist of induction chemotherapy as initially established in the Veterans’ Administration Larynx Preservation trial and of concomitant chemoradiotherapy. Randomized trials established the combination of cisplatin and fluorouracil (PF) as induction chemotherapy and of radiotherapy with systemic-dose cisplatin every 3 weeks as feasible and effective. 1-3 More recently, the addition of docetaxel to the PF regimen (TPF) was shown to further increase overall survival when compared with PF in a general population of patients with head and neck cancer and to allow for a higher larynx preservation rate in patients with laryngeal and hypopharyngeal cancer. 4-6 Bioradiotherapy by using concurrent cetuximab was shown to be superior to single-modality radiotherapy but has not been directly compared with either induction or concurrent chemoradiotherapy, tested specifically for laryngeal cancer, or shown to further improve survival when added to cisplatin radiotherapy. 7,8 Viral carcinogenesis of nasopharyngeal cancer (Epstein-Barr virus) and oropharyngeal cancer (human papillomavirus) is well recognized; in particular, the latter is associated with the current rapid increase in the incidence of oropharyngeal cancers. However, for larynx cancer, tobacco and alcohol exposure remain the dominant risk factors that lead to frequent significant comorbidities and competing mortality risks. In addition, laryngeal cancer can predispose patients to swallowing problems with associated malnutrition and aspiration. Similarly, acute and long-term effects of surgery and radiation can contribute to these complications, especially in older patients and patients with advanced stage disease. 9 In the article that accompanies this editorial, Forastiere et al 10 report 5- and 10-year outcomes for Radiation Therapy Oncology

金属氧化物半导体场效应管长期辐射效应的数值模拟

金属氧化物半导体场效应管长期辐射效应的数值模拟

Medical Planning and Response for a Nuclear Detonation: A Practical Guide

This article summarizes major points from a newly released guide published online by the Office of the Assistant Secretary for Preparedness and Response (ASPR). The article reviews basic principles about radiation and its measurement, short-term and long-term effects of radiation, and medical countermeasures as well as essential information about how to prepare for and respond to a nuclear detonation. A link is provided to the manual itself, which in turn is heavily referenced for readers who wish to have more detail.

PO-43: Long-Term Effects of Irradiation on The Phenotype of Human Glioblastoma Cells

PO-43: Long-Term Effects of Irradiation on The Phenotype of Human Glioblastoma Cells

Primary Care Providers' Needs and Preferences for Information about Colorectal Cancer Survivorship Care

The Institute of Medicine (IOM) proposed that cancer survivors and their primary care providers (PCPs) should receive survivorship care plans to inform ongoing care. We aimed to determine PCPs' preferences for the content of survivorship care plans for colorectal cancer (CRC) survivors. PCPs in 3 practice-based research networks completed a survey regarding 45 topics of CRC information based on the IOM's survivorship care plan framework. One hundred fifty-six PCPs completed the survey. For 35 topics (78%), at least half of respondents felt the topic was very important. Most PCPs reported receiving too little information about problems with chemotherapy (68%) or radiation (60%) and whether the oncologist intended to monitor for other cancers (71%). PCPs widely agreed that they do not have enough information about increased risk of second CRCs, other cancers, and other diseases (78%); long-term effects of chemotherapy (73%) and radiation (67%); and genetic counseling (83%). PCPs endorse the IOM's survivorship care plan framework as relevant and often report needing more information. Survivorship care plans may provide important information to PCPs by communicating patients' cancer histories and making recommendations regarding which aspects of care should be provided by the oncologist or the PCP.

Radiation induced esophageal adenocarcinoma in a woman previously treated for breast cancer and renal cell carcinoma

BackgroundSecondary radiation-induced cancers are rare but well-documented as long-term side effects of radiation in large populations of breast cancer survivors. Multiple neoplasms are rare. We report a case of esophageal adenocarcinoma in a patient treated previously for breast cancer and clear cell carcinoma of the kidney.Case presentationA 56 year-old non smoking woman, with no alcohol intake and no familial history of cancer; followed in the National Institute of Oncology of Rabat Morocco since 1999 for breast carcinoma, presented on consultation on January 2011 with dysphagia. Breast cancer was treated with modified radical mastectomy, 6 courses of chemotherapy based on CMF regimen and radiotherapy to breast, inner mammary chain and to pelvis as castration. Less than a year later, a renal right mass was discovered incidentally. Enlarged nephrectomy realized and showed renal cell carcinoma. A local and metastatic breast cancer recurrence occurred in 2007. Patient had 2 lines of chemotherapy and 2 lines of hormonotherapy with Letrozole and Tamoxifen assuring a stable disease. On January 2011, the patient presented dysphagia. Oesogastric endoscopy showed middle esophagus stenosing mass. Biopsy revealed adenocarcinoma. No evidence of metastasis was noticed on computed tomography and breast disease was controlled. Palliative brachytherapy to esophagus was delivered. Patient presented dysphagia due to progressive disease 4 months later. Jejunostomy was proposed but the patient refused any treatment. She died on July 2011.ConclusionWe present here a multiple neoplasm in a patient with no known family history of cancers. Esophageal carcinoma is most likely induced by radiation. However the presence of a third malignancy suggests the presence of genetic disorders.

In-situ strain analysis of potential habitat composites exposed to a simulated long-term lunar radiation exposure

NASA is studying the effects of long-term space radiation on potential multifunctional composite materials for habitats to better determine their characteristics in harsh space environments. Two epoxy-matrix composite materials were selected for the study and were mounted in a test stand that simulated the biaxial stresses of a pressure vessel wall. The samples in the test stand were exposed to radiation at fast (0.1478krad/s) and slow (0.0139krad/s) dose rates, and the strain and temperature were recorded during the exposure. During a fast dose rate exposure, negative strain was recorded, decreasing with time, an indication of matrix shrinkage. Given previous radiation studies of polymers, this is expected to be a result of radiation-induced crosslinking in the epoxy matrix. However, with a slow dose rate, the materials exhibited a positive strain that increased with time, corresponding to stretching of the materials. This result is consistent with scission or degradation of the matrix occurring, possibly due to oxidative degradation.

Accuracy of Intraoperative Fluoroscopy with and without Laser Guidance in Foot and Ankle Surgery

The use of intraoperative fluoroscopy in orthopedic surgery involves frequent exposure to ionizing radiation in the operating room. Although a number of studies have found radiation exposure to orthopedic surgeons to be well below recommended doses, the long-term effects of low-dose radiation are not well known. Thus, all effective practical methods should be undertaken to reduce the exposure to radiation. Our purpose was to determine whether the use of a laser-aiming device improves the accuracy of intraoperative fluoroscopy to reduce, by implication, radiation exposure in the operating room. From March to October 2004, there were 92 consecutive cases requiring use of fluoroscopy in the orthopedic foot and ankle service of the authors' institution. The number of accurate and inaccurate images with or without the presence of a radiology technician and a laser-aiming device were compared. The accuracy of imaging with the laser-aiming device was higher than the imaging without the device (p < 0.001). The accuracy of the images obtained by the surgeon was higher than the technicians' images when laser guidance was used (p= 0.027). There was no significant difference between the images obtained by the surgeon or the technicians when the aiming device was not used (p = 0.09). The use of a laser-aiming device to help position during fluoroscopy is recommended in an effort to reduce radiation exposure in foot and ankle surgery.

Traces of eruption of Eyjafjallajökull volcano according to data of lidar observations in Tomsk and Surgut

We present the results of lidar measurements of the vertical distribution of optical parameters of anomalous aerosol formations in the atmosphere and the polarization state of backscattered sounding radiation, obtained in Tomsk (56.48°N; 85.05°E) and Surgut (61.25°N; 73.43°E) in April–May 2010. Data from measurements using back trajectory analysis of atmospheric air-mass transport according to the NOAA HYSPLIT MODEL showed that the observed anomalous aerosol formations were due to transport of the products of the Eyjafjallajokull volcano eruption in Iceland (April 14, 2010). First traces of the volcanic eruption were recorded in the troposphere over Tomsk on April 19. The volcanic aerosol persisted in the troposphere for about 10 days in total; it penetrated into the stratosphere insignificantly and could not have noticeable long-term radiation and thermal effects.

Unrepairable DNA double-strand breaks that are generated by ionising radiation determine the cell fate of normal human cells

After an exposure to ionising radiation, cells can quickly repair damage to their genomes; however, a few unrepairable DNA double-strand breaks (DSBs) emerge in the nucleus in a prolonged culture and perpetuate as long as the culture continues. These DSBs may be retained forever in cells such as non-dividing ageing tissues, which are resistant to apoptosis. We show that such unrepairable DSBs, which had been advocated by the classical target theory as the 'radiation hit', could account for permanent growth arrest and premature senescence. The unrepairable DSBs build up with repeated irradiation, which accounts for an accumulated dose. Because these DSBs tend to be paired, we propose that the untethered and 'torn-off' molecular structures at the broken ends of the DNA result in an alteration of chromatin structure, which protects the ends of the DNA from genomic catastrophe. Such biochemical responses are important for cell survival but may cause gradual tissue malfunction, which could lead to the late effects of radiation exposure. Thus, understanding the biology of unrepairable damage will provide new insights into the long-term effects of radiation.

Advances in ultra-high field MRI for the clinical management of patients with brain tumors

The last 5 years have seen the number of ultra-high field (UHF; 7 T and beyond) MRI scanners nearly double. Benefits include improved specificity, better sensitivity for signal-starved compounds, and the ability to detect, quantify, and monitor tumor activity and treatment effects. This is especially important in the current climate in which new treatments alter established markers of tumor and the surrounding environment, confounding traditional response criteria. Intra-tumoral heterogeneity and dramatic improvement in spatial localization have been observed with 7 and 8 T high-resolution T2-weighted and T2*-weighted imaging. This depiction of lesions that were not readily detected at lower field improved the classification of glioma. Sub-millimeter visualization of microvasculature has facilitated the detection of microbleeds associated with long-term effects of radiation. New metabolic markers seen at UHF may also assist in distinguishing tumor progression from treatment effect. Although progress has been limited by technical challenges, initial experience has demonstrated the promise of 7-T MRI in advancing existing paradigms for diagnosing, monitoring, and managing patients with brain tumors. The success of these systems will depend upon what new information can be gained by UHF, rather than simply improving the quality of the current lower field standard.

Cost-effectiveness of reducing radiation in Crohn's disease

Crohn's disease is a life-long illness, with patients increasingly being exposed to diagnostic medical radiation. Diagnostic strategies are being re-evaluated after concerns were raised over the long-term effects of medical radiation. A recent study explored the cost-effectiveness of a magnetic resonance enterography program in patients with Crohn's disease, which could reduce the risk of radiation-induced neoplasia.

MEASUREMENT ERRORS IN THE ASSESSMENT OF EXPOSURE TO SOLAR ULTRAVIOLET RADIATION AND ITS IMPACT ON RISK ESTIMATES IN EPIDEMIOLOGICAL STUDIES

Background and Aims: To date, many studies addressing long-term effects of ultraviolet radiation (UVR) exposure on human health have relied on a range of surrogates such as the latitude, ambient UV...