[Coenzyme Q (ubiquinone) as a behavioural modifier in rats, subjected to low-background ionizing radiation].
Explore the source record for details and available documents.
Animals↗
SEARCH · Search PubMed
Results for “Background Radiation”
Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
A case of radiation recall mucositis associated with docetaxel.
BACKGROUND: Radiation recall reactions, in particular dermatitis, are well documented in the literature. However, radiation recall mucositis is a rare clinical phenomenon. METHODS: We report a case of a 45-year-old man diagnosed with squamous cell carcinoma of the base of tongue. He was treated with surgery followed by chemotherapy and radiation therapy. Several months after completing treatment, he had a recurrence develop outside of the previously irradiated field. He was offered radiation therapy concurrent with docetaxel as salvage therapy. RESULTS: During salvage therapy, acute recall mucositis developed corresponding to his previously irradiated fields. His chemotherapy with docetaxel was withheld, and his symptoms rapidly improved. CONCLUSIONS: This case describes radiation recall mucositis associated with docetaxel, a rare but potentially serious clinical situation. Given the potential severity of the reaction and increasing use of docetaxel as second-line treatment of recurrent head and neck cancers, it is important to be aware of this phenomenon.
Antineoplastic Agents, Phytogenic↗
Documentation of radiation-induced oral mucositis. Scoring systems.
BACKGROUND: Radiation therapy of tumors in the head and neck region is frequently associated with severe side effects in the oral mucosa which often necessitate interruption of the prescribed treatment protocol. In order to compare therapeutic strategies and, more important, in order to perform multi center studies, generally accepted scoring systems have to be applied for uniform documentation of the oral mucosal response. METHODS: Different scoring protocols are found in the literature. The scoring protocols most widely accepted are the CTC classification and the RTOG/EORTC classification. These are compared with more detailed systems. RESULTS: In the CTC classification, grading of stomatitis is included in the responses of the gastrointestinal tract and emphasizes dietary effects. For effects of radiation alone or of radiochemotherapy, the RTOG/EORTC system, focusing on therapeutic interventions, has been established. However, there are only minor differences in the grading of mucositis between these 2 protocols. Based on the RTOG/EORTC classification, Maciejewski et al. introduced a classification system with inclusion of the area affected, but also changed the sensitivity of the scores. The latter may be confusing if the source of the system used is not cited in a report. An alternative system was proposed by Dische, which in addition to objective morphologic criteria also includes the symptoms induced by the mucosal response, and hence includes some subjective aspects reported by the patient. CONCLUSIONS: For routine documentation of acute radiation side effects in the oral cavity, the German version of the RTOG/EORTC classification can be recommended. In studies with particular interest in oral mucositis, a more sensitive scoring system may be applied. In any publication concerning mucositis, a table or a detailed description of the system used should be included.
Documentation↗
Objective evaluation of the quality of voice following radiation therapy for T1 glottic cancer.
BACKGROUND: Radiation therapy is commonly considered the treatment of choice for T1 glottic cancer. While it is generally believed that the quality of voice following irradiation is quite satisfactory, few studies have reported the results of objective assessment of voice after radiation therapy. PURPOSE: To objectively evaluate the quality of voice following radiation therapy for T1 glottic cancer. MATERIALS AND METHODS: The voices of 12 patients treated for T1 glottic cancer with radiation therapy were evaluated by acoustic analysis and speech aerodynamic studies. Eleven patients received between 6300 and 6665 cGy at a daily fraction size of 180-225 cGy. One patient received 7000 cGy at a daily fraction size of 200 cGy. Evaluation of the quality of voice was done 3 months to 7 years following completion of radiation therapy. RESULTS: The number of patients who scored abnormal values for the measurements of fundamental frequency, jitter, shimmer and harmonic to noise ratio was 2, 10, 4 and 3, respectively. The number of patients who scored abnormal values for transglottic airflow rate, subglottal pressure and glottal resistance was 12, 8 and 9, respectively. None of the studied patients scored normal values in all given tests. CONCLUSION: Although radiation therapy cures a high proportion of patients with T1 glottic cancer, the quality of voice does not return to normal following treatment.
Acoustics↗
The relationship between MMPs and pH in whole saliva of radiated head and neck cancer patients.
BACKGROUND: Radiation therapy for head and neck tumour patients may lead to decreased salivary flow, oral mucosal lesions and increased caries experience. Salivary matrix metalloproteinases (MMPs) may participate in the pathogenesis of mucosal lesions and dentinal caries. The aims of this study were: (i) to assay the presence, molecular forms and proteolytic activity of MMP-8 (collagenase-2) and MMP-9 (gelatinase B) in the whole saliva of head and neck cancer patients having radiation therapy; (ii) to see whether salivary pH affects the activity of MMP-8 and MMP-9; and (iii) to find out the possible connection between MMP-8 and MMP-9 with the eruption of oral mucosal lesions during radiation therapy. METHODS: The whole saliva samples of 39 head and neck cancer patients having radiation therapy were collected before, during and after radiation therapy, and saliva flow rate, pH, buffer capacity, Streptococcus mutans, Lactobacillus and Candida albicans were measured. Any oral mucosal lesions were examined during each visit. The levels of MMP-8 were measured by immunofluorometric assay (IFMA) and the presence of different MMP-8 forms was analysed using Western immunoblotting. The presence and molecular forms of MMP-9 were analyzed by gelatin zymography. MMP-9 capture activity assay was used to determine the APMA-activated MMP-9 activity (total) and the endogenously active MMP-9 (free activity). RESULTS: Salivary flow rate, buffer capacity and pH decreased, and the levels of Lactobacilli increased significantly, during the first half of the radiation therapy. The endogenously activated salivary MMP-9 correlated with low salivary pH (P = 0.013). No connection was found between the oral mucosal lesions and salivary MMP-8 or MMP-9. CONCLUSIONS: In this study, salivary MMP-8 or MMP-9 did not correlate with the presence of radiation induced oral mucosal lesions, but the activation of MMP-9 may be dependent on pH.
Adult↗
The Tradescantia-micronucleus test on the genotoxicity of UV-B radiation.
Lanzhou city is located in north central China near inner Mongolia. The solar UV-B background radiation in this area is occasionally extremely high (8 microW/cm2). Such high background solar UV-B radiation could be attributed to the sporadic depletion of the ozone layer in the stratosphere. The excessive UV-B radiation is a potential hazard in the environment. This prompted the present study on the effect of UV-B radiation on the cytogenetic damage to pollen mother cells of the plant Tradescantia. The Tradescantia-micronucleus (Trad-MCN) test was used to determine the genotoxicity of UV-B radiation. In addition to the usual 10 h of solar emission of UV light a series of increasing dosages (2, 4, 6, 8 h) of artificial UV-B radiation was applied to Tradescantia (clone 3) plant cuttings. Inflorescences of the treated and control plants were fixed and used for preparation of microslides. Micronuclei frequencies were observed in the early tetrads to show the degree of genotoxicity. Results of two repeated experiments show a dose-related increase of MCN frequencies under normal sunshine days. In the third experiment conducted under a cloudy and rainy day and an extraordinary high solar UV-B background, the MCN frequencies were markedly higher than that of the negative control but did not show the clear dose response to the treatment as in the first two experiments. The Trad-MCN test has successfully detected the effect of artificial UV-B radiation over the solar UV-B background radiation.
China↗
Moderate dose rate ionizing radiation increases longevity.
This paper presents little-known data to support the hypothesis that we need increased background radiation to improve our health. Attention will be drawn to results that demonstrate health benefits of ionizing radiation that have been largely ignored by the news media.
Background Radiation↗
Carcinoma of the rectum. Possible cellular predictors of metastatic potential and response to radiation therapy.
BACKGROUND: Preoperative radiation therapy can markedly improve local control of rectal carcinoma. However, some tumors do not respond well to moderate doses of preoperative radiation and would be better served by more aggressive preoperative treatment (e.g., chemoradiotherapy). Cellular predictors of responsiveness to radiation can help to select lesions for more aggressive treatment. In addition, there is a need for cellular predictors of metastatic potential. This is particularly important in the setting of preoperative radiation-downstaging by preoperative treatment can obscure the true pathologic stage of a tumor and confound the usual selection criteria for postoperative chemotherapy. PURPOSE: This study was undertaken to determine if proliferating cell nuclear antigen (PCNA), p53, DNA ploidy, and S-phase fraction are associated with response to radiation and/or risk for distant metastatic disease and to determine if these cellular markers are best evaluated from preradiation biopsy specimen or the larger (but possibly altered) final surgical specimen. MATERIALS AND METHODS: Archival specimens from 23 cases of ultrasound T3 or T4 rectal carcinoma treated preoperatively with radiation therapy were reviewed. Eligible lesions had preradiation biopsy specimens of sufficient size for flow cytometric review of archival tissue. Factors considered included PCNA positivity, presence of mutant nuclear p53, more than 30 percent tumor cells in S-phase, and presence of aneuploidy. RESULTS: With a median follow-up of three years, overall freedom from relapse was 83 percent, with all but one failure being extrapelvic. PCNA positivity in the preradiation specimen was significantly (P = 0.025) associated with a greater risk of tumor recurrence. In addition, there was a trend to greater likelihood of "probable downstaging" (defined as surgical T stage less than preradiation ultrasound T stage) for lesions that were PCNA-negative or lesions with normal p53. Biomarkers measured in the postradiation surgical specimen were not associated with either freedom from relapse or response to radiation. Radiation treatment appeared to produce false-negatives in the final specimen. Thus, there were significantly more specimens converting from PCNA-positive to PCNA-negative after preoperative radiation than would be expected solely on the basis of sampling errors (P = 0.004). Similar results were found for abnormal p53 findings (P = 0.02). CONCLUSIONS: Prospective studies of biomarkers should be based on pretreatment specimens if preoperative radiation is given. For carcinoma of the rectum, PCNA and p53 may be useful predictors of both metastatic potential and responsiveness to radiation.
Adenocarcinoma↗
Argon plasma coagulation therapy for hemorrhagic radiation proctosigmoiditis.
BACKGROUND: Radiation-induced proctosigmoiditis is a serious complication of pelvic radiation therapy. Rectal bleeding occurs among 6% to 8% of these patients and is extremely difficult to manage. Pharmacotherapy is generally ineffective, whereas surgical treatment is associated with high morbidity and mortality. Argon plasma coagulation is a new method of noncontact electrocoagulation well suited for hemostasis of large bleeding areas. METHODS: From December 1996 through March 1998, we used argon plasma coagulation to treat 28 patients with hemorrhagic radiation-induced proctosigmoiditis. Indications for treatment were anemia (n = 18) and persistent bleeding despite pharmacotherapy (n = 10). Argon flow and electrical power were set at 1.5 L/min and 50 W. The severity of rectal bleeding was graded from 0 to 4 (highest), and hemoglobin levels were recorded before and after treatment. RESULTS: Eighty-two therapeutic sessions were performed (median 2.9 sessions per patient). The severity score for rectal bleeding dropped at least 1 point for all but 2 patients, and the mean value decreased from 2.96 to 0.68. Average hemoglobin level increased 1.2 gm/dL (1.9 gm/dL among anemic patients). No serious complications were observed. CONCLUSIONS: Argon plasma coagulation appears to be a simple, safe, and effective technique in the management of hemorrhagic radiation-induced proctosigmoiditis.
Adult↗
Long-term outcome of argon plasma coagulation therapy for bleeding caused by chronic radiation proctopathy.
BACKGROUND: Radiation-induced proctopathy is a serious complication of radiation therapy for pelvic malignancy. AIM: To assess the safety and efficacy of argon plasma coagulation in the treatment of haemorrhagic radiation-induced proctopathy. PATIENTS: Twenty-four patients with rectal bleeding due to radiation-induced proctopathy were prospectively enrolled in the study. METHODS: Indications for treatment were iron deficiency anaemia (n = 16) and persistent bleeding, despite pharmacotherapy (n = 8). Argon flow and power used were 0.8-1.2 l/min and 40 W, respectively. An interval of at least 4 weeks was allowed between treatment sessions. Haemoglobin level, bleeding severity score, number of admissions and transfusion requirements were recorded after endoscopic coagulation and before 12 and 24 months. RESULTS: A median of 2.5 therapeutic sessions per patient were performed (range 1-6). All patients reported clinical improvement and/or cessation of rectal bleeding. The mean value of the bleeding severity score decreased from 2.9 to 0.8 (P < 0.01), while average haemoglobin levels increased by a mean of 1.9 mg/dl at the end of the treatments (P < 0.05). During a minimum follow-up of 24 months (range 24-60), rectal bleeding recurred in two cases and was successfully retreated endoscopically. One patient developed a recto-vaginal fistula. CONCLUSIONS: Argon plasma coagulation appears to be a safe and effective technique for management of rectal bleeding caused by radiation-induced proctopathy.
Adult↗
Cerebral radiation necrosis.
BACKGROUND: Brain radiation necrosis has been recognized as a potential complication of radiation therapy for cancer for at least five decades. Advances in neuro-radiology and histopathology have helped characterize this problem more fully and some therapeutic interventions may help prevent progression of this pathology. This is important in achieving one of the most important goals of cancer care-maintaining quality of life. REVIEW SUMMARY: This review discusses the evolution of our understanding of radiation necrosis, from the first "autopsy-dependent" reports to the current characterization of these lesions with magnetic resonance (MR) and functional imaging. The review is presented in two parts; Part I deals with the definition, incidence and presumed pathogenesis of radiation necrosis. Part II includes diagnosis on the basis of imaging characteristics, (including functional imaging) and biopsy results. Management options are also explored. CONCLUSIONS: Radiation necrosis is a very significant complication of radiation treatment of brain cancers and may have a tremendous impact on a patient's quality of life. The early diagnosis of radiation necrosis in patients receiving radiation therapy to the brain has improved with current neuro-imaging modalities and better understanding of its pathophysiology. The development of treatment modalities has been slower, but is nonetheless promising.
Autopsy↗
Predicting patients at low probability of requiring postmastectomy radiation therapy.
BACKGROUND: Postmastectomy radiation therapy (PMRT) is recommended for patients with four or more positive lymph nodes (LN+). Given the ramifications of PMRT for immediate reconstruction, we sought to create a model using preoperative and intraoperative factors to predict which patients with a positive sentinel lymph node will have less than four LN+. METHODS: The database from a prospective multicenter study of 4,131 patients was used for this analysis. Patients with one to three positive sentinel lymph nodes (SLN) and tumors < 5 cm (n = 1,133) in size were randomly divided into a training set (n = 580) and a test set (n = 553). Multivariate logistic regression was used on the training set to create a prediction rule that was subsequently validated in the test set. RESULTS: Median patient age was 57 (range, 27-100) years, and median tumor size was 2.0 (range, 0.2-4.8) cm. In the training set, factors associated with having four or more LN+ on multivariate analysis were: tumor size [odds ratio (OR) = 2.087; 95% confidence interval (CI): 1.307-3.333, P = 0.002), number of positive SLN (P < 0.0005), and proportion of positive SLN (OR = 3.602; 95% CI: 2.100-6.179, P < 0.005). A predictive model was established with a point assigned to each positive SLN, T2 (vs. T1), and if proportion of positive SLN was > 50%, for a maximum of five points. In both the training and test sets, patients with one point had a low probability of having four or more LN+ (3.8% and 3.3%, respectively). CONCLUSION: Tumor size, number of positive SLN, and the proportion of positive SLN influence whether patients will have four or more LN+. A simple model can predict the probability of requiring PMRT.
Adult↗
Formalin dab for haemorrhagic radiation proctitis.
BACKGROUND: Haemorrhagic radiation proctitis frequently presents as a problem in management. We analysed the technique of formalin dab in its management. PATIENTS AND METHODS: Twenty patients presenting with haemorrhagic radiation proctitis and treated with formalin dab were prospectively analysed. RESULTS: Twelve patients ceased to bleed following one session of formnalin dab. Six patients needed more than one session to effect haemostasis. Two of three patients with torrential bleeding failed to respond to formalin dab and required surgical excision of the rectum. CONCLUSION: Formalin dab is a simple, effective and safe treatment modality in the management of chronic haemorrhagic radiation proctitis, and hence should be considered as the initial treatment modality for such a condition.
Adult↗
Management of radiofrequency radiation overexposures.
BACKGROUND: Radiofrequency radiation (RFR) has been in use for some time but is now proliferative with the burgeoning radiocommunications industry. OBJECTIVE: To inform the profession of the possible health effects from overexposure to radiofrequency radiation (RFR) and the clinical approach to cases. An introduction to the health effects of overexposure to RFR is given. A clinical approach to integrating the patient's symptoms and the circumstances of the exposure is given. Emergency treatment and ongoing care is outlined, and sources of expert advice given. CONCLUSION: Overexposure to RFR is a complex injury. Advice is given in this article for emergency care and planning ongoing care.
Adult↗
Cost-effectiveness of proton radiation in the treatment of childhood medulloblastoma.
BACKGROUND: Radiation therapy is an important component in the treatment of medulloblastoma; however, in many patients, it is associated with risk of late adverse events. Proton radiation therapy has potential to reduce the risk of adverse events compared with conventional radiation, but it is associated with a higher treatment cost. The objective of the current study was to assess the cost-effectiveness of proton therapy compared with conventional radiation therapy in the treatment of childhood medulloblastoma. METHODS: The consequences of radiation therapy were evaluated using a Markov simulation model. Children age 5 years with medulloblastoma were followed. The patients were at risk of several types of adverse events, including hearing loss, intelligence quotient (IQ) loss, hypothyroidism, growth hormone deficiency (GHD), osteoporosis, cardiac disease, and secondary malignancies. The patients also were at risk of death and were divided into risk groups for normal death, death due to tumor recurrence, treatment-related cardiac death, treatment-related subsequent tumor death, or treatment-related other death. A review of the literature was conducted to estimate the parameters in the model. RESULTS: The base-case results showed that proton therapy was associated with 23,600 in cost savings and 0.68 additional quality-adjusted life-years per patient. The analyses showed that reductions in IQ loss and GHD contributed to the greatest part of the cost savings and were the most important parameters for cost-effectiveness. CONCLUSIONS: The results of the current study indicated that proton radiation therapy can be cost-effective and cost-saving compared with conventional radiation therapy in the treatment of children with medulloblastoma if the appropriate patients are selected for the therapy. However, there have been few long-term follow-up studies, and more much information on the long-term consequences of radiation therapy is needed.
Cerebellar Neoplasms↗
Increased expression of cyclooxygenase-2 (COX-2) in radiation-induced small bowel injury in rats.
BACKGROUND: Radiation therapy is a widely used adjuvant therapy for various abdominal and pelvic cancers. On the other hand, it is not a benign treatment modality, as most radiation patients suffer from some kind of radiation enteritis. Currently available treatments are only palliative and no ideal compound has as yet been discovered. The aim of this study was to evaluate cyclooxygenase-2 (COX-2) expression, and to investigate the possible protective effect of the selective COX-2 inhibitor, Rofecoxib, in acute and late stages of radiation-induced intestinal injury in rats. MATERIALS AND METHODS: Forty-eight male Sprague-Dawley rats were randomly divided into eight groups. After abdominal irradiation of all of the animals except the six in the control group, the expression of the enzyme cyclooxygenase-2 (COX-2) was evaluated in different cell types present in the intestinal wall 2 h post exposure (study day 0) and again on study days 4, 14, and 60. The effects of Rofecoxib on histological damage, intestinal myeloperoxidase (MPO) activity, and malondialdehyde (MDA) levels were also measured. RESULTS: Expression of COX-2 in vascular endothelial cells was found to be significantly increased on post exposure days 4 and 14 (2.4 and 2.9 stained vessels/high power field [hpf] respectively compared to 1.3 vessels/hpf for controls) (P = 0.002). Expression of COX-2 in fibroblasts increased immediately after irradiation (29 cells/hpf 2 h after irradiation compared to 12 cells/hpf for non-irradiated control animals) and remained high during the entire study period (P < 0.001), whereas there was a peak COX-2 expression (54.9 cells/hpf) on day 14 that was similar to what was observed in endothelial cells. Irradiation of rats significantly increased intestinal epithelial damage, MPO activity, and MDA levels in comparison to the control group in a time-dependent fashion. Treatment with rofecoxib significantly decreased these elevations except on day 4 of the study. CONCLUSION: The current study suggests that the COX-2 pathway is involved in radiation induced intestinal injury and that targeting COX-2 may be useful in limiting radiation enteritis.
Acute Disease↗
Selective vulnerability to radiation in the hippocampal dentate granule cells.
BACKGROUND: Radiation therapy is an effective approach in the treatment of highly radiosensitive brain tumors such as germinomas. However, recent studies have reported intellectual disturbances in patients who underwent whole-brain irradiation as children. We detected apoptosis in the infantile murine cerebrum after systemic X-ray irradiation. METHODS: Subjects were 100 ICR mice 4 weeks old, of which 90 were systemically exposed to 18 Gy X-rays (0.45 Gy/min); 10 each were decapitated and the cerebrums were removed 1, 3, 6, 9, 12, 18, 24, 48, and 72 hours after irradiation. Controls were 10 unirradiated mice. DNA fragmentation analysis was carried out by agarose gel electrophoresis, and morphological analysis was by the TUNEL method. RESULTS: According to agarose gel electrophoresis, the cerebral DNA ladders were detected only over 6 to 24 hr, peaking in 9 hr. Even at the peak, band intensity was nearly double that of the unirradiated normal thymus. According to the TUNEL analysis, radiation-induced apoptosis increased, with a peak at 9 hours, but decreased 24 hours after irradiation. Apoptotic cells were always localized exclusively in the hippocampal dentate granule cells. CONCLUSIONS: We found that vulnerability to radiation existed in the hippocampal dentate granule cells. Intellectual disturbances in patients who have undergone whole-brain irradiation may be caused by injury to the hippocampus.
Acute Disease↗
Radiation induced osteogenic sarcoma of the maxilla.
BACKGROUND: Radiation induced sarcoma arise as a long term complication of radiation treatment for other benign or malignant conditions. They are of very rare occurrence in jaw bones and are even rarer in maxilla. CASE PRESENTATION: Here we report a case of radiation induced sarcoma in a patient treated for squamous cell carcinoma of buccal mucosa with radiation who developed osteosarcoma of maxillary bone after six years. The patient was treated successfully with surgery. CONCLUSION: What should be the best treatment of radiation induced sarcoma is still debatable; however, surgery offers the best chance of cure. Role of reradiation and adjuvant chemotherapy needs to be further evaluated.
Journal Article↗