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Relationship between residual radiation-induced DNA double-strand breaks in cultured fibroblasts and late radiation reactions: a comparison of training and validation cohorts of breast cancer patients.

BACKGROUND AND PURPOSE: Using pulsed field gel electrophoresis (PFGE) a significant correlation was demonstrated between residual DNA double-strand breaks (dsbs) and the development of late radiation fibrosis in a group of 39 breast cancer patients studied retrospectively. This group formed a training cohort generating a hypothesis that there is a relationship between residual radiation-induced DNA dsbs in cultured fibroblasts and late radiotherapy reactions in breast cancer patients. The aim of this study was to retest and validate the hypothesis. MATERIALS AND METHODS: The study was retrospective. Skin biopsies were taken from a validation cohort of 50 breast cancer patients and PFGE was used to examine residual radiation-induced dsbs in cultured fibroblasts. Late morbidity was measured clinically as fibrosis and using the late effects on normal tissues scales that incorporate subjective, objective management and analytic data (LENT SOMA). RESULTS: PFGE data were obtained for 49 biopsies. In the 49 patients there was no correlation between residual DNA damage and either fibrosis (r=-0.027, P=0.85) or LENT SOMA (r=-0.10, P=0.48) scores. There was no significant relationship between residual damage and fibrosis for the combined training and validation cohorts of 88 patients (r=0.20, P=0.063). CONCLUSIONS: This study did not validate the hypothesis that there is a relationship between fibroblast residual DNA damage and late morbidity in breast cancer patients. The PFGE assay on fibroblasts is not a suitable test of the degree of late radiation-induced fibrosis in the breast.

Aged↗

Geographical miss during catheter-based intracoronary beta-radiation: incidence and implications in the BRIE study. Beta-Radiation In Europe.

OBJECTIVES: We sought to determine the incidence and causes of geographical miss (GM) and to evaluate its impact on edge restenosis after intracoronary beta-radiation therapy. BACKGROUND: Edge restenosis is a limitation of intracoronary beta-radiation therapy. Geographical miss is the situation in which the radiation source does not fully cover the injured segment and may lead to edge restenosis. METHODS: We analyzed 175 vessels treated according to the Beta-Radiation In Europe (BRIE) study protocol. The effective irradiated segment (EIRS) and both edges were studied with quantitative coronary angiography. The edges of the EIRS that were injured constituted the GM edges. Restenosis was defined as diameter stenosis >50% at follow-up. Geographical miss was determined by simultaneous electrocardiographic-matched, side-by-side projection of the source and balloons deflated at the injury site, in identical angiographic projections surrounded by contrast. RESULTS: Geographical miss affected 41.2% of the edges and increased edge restenosis significantly compared with non-GM edges (16.3% vs. 4.3%, respectively, p = 0.004). Restenosis was increased both in the proximal (p = 0.05) and distal (p = 0.02) GM edges compared with noninjured edges. Geographical miss associated with stent injury significantly increased edge restenosis (p = 0.006), whereas GM related to balloon injury did not significantly increase edge restenosis (p = 0.35). The restenosis in the EIRS was similar between vessels with and without GM (24.3% and 21.6%, respectively, p = 0.8). CONCLUSIONS: Geographical miss is strongly associated with restenosis at the edges of the EIRS. This effect is more prominent when caused by stenting. Geographical miss does not increase restenosis in the EIRS.

Adult↗

Intensity-modulated radiation therapy (IMRT): the radiation oncologist's perspective.

Intensity-modulated radiation therapy (IMRT) is a new and evolving technological advance in high-precision radiation therapy. It is an extension of 3-dimensional conformal radiotherapy (3D-CRT) that allows the delivery of highly complex isodose profiles to the target while minimizing radiation exposure to surrounding normal tissues. Clinical data on IMRT are emerging and being collected, as more institutions are implementing or expanding the use of IMRT. However, the currently available IMRT and its applications are far from being well understood and established. In some circumstances, it remains impractical and too costly. This article discusses some practical issues from the radiation oncologist's perspective.

Attitude of Health Personnel↗

Radiation-induced bone sarcoma following total body irradiation: role of additional radiation on localized areas.

A 44-year-old patient who had had acute monoblastic leukemia developed an osteosarcoma of the pelvic bones 5 years after an allogeneic bone marrow transplant from his HLA-identical sister. He had additionally received superficial cutaneous radiation of the legs and pelvis, over the 3 weeks prior to total body irradiation (TBI), because of cutaneous leukemic lesions. The tumor was a fibrohistiocytomatous osteogenic sarcoma. The first lesion was in the right ilium, and a second lesion appeared 18 months later, symmetrically on the left ilium. Despite treatment, the patient died from metastases. At the time of diagnosis of radiation-induced sarcoma, the patient was free of leukemia and had several risk factors already reported to favor the development of solid tumors in stem cell recipients. These include acute leukemia, TBI and graft-versus-host disease. As he developed symmetrical lesions of the pelvic bone, and because of the histology of the radiation-induced tumor, we assumed that the additional radiation of the skin prior to TBI may have contributed to the pathogenesis of this malignant fibrous histiocytoma. Therefore, the risk/benefit ratio should be carefully considered in unusual indications. These patients should benefit from a close follow-up of the superimposed areas.

Adult↗

Ionizing radiation enhances therapeutic activity of mda-7/IL-24: overcoming radiation- and mda-7/IL-24-resistance in prostate cancer cells overexpressing the antiapoptotic proteins bcl-xL or bcl-2.

Subtraction hybridization applied to terminally differentiating human melanoma cells identified mda-7/IL-24, a cytokine belonging to the IL-10 gene superfamily. Adenoviral-mediated delivery of mda-7/IL-24 (Ad.mda-7) provokes apoptosis selectively in a wide spectrum of cancers in vitro in cell culture, in vivo in human tumor xenograft animal models and in patients with advanced carcinomas and melanomas. In human prostate cancer cells, a role for mitochondrial dysfunction and induction of reactive oxygen species in the apoptotic process has been established. Ectopic overexpression of bcl-xL and bcl-2 prevents these changes including apoptosis induction in prostate tumor cells by Ad.mda-7. We now document that this resistance to apoptosis can be reversed by treating bcl-2 family overexpressing prostate tumor cells with ionizing radiation in combination with Ad.mda-7 or purified GST-MDA-7 protein. Additionally, radiation augments apoptosis induction by mda-7/IL-24 in parental and neomycin-resistant prostate tumor cells. Radiosensitization to mda-7/IL-24 is dependent on JNK signaling, as treatment with the JNK 1/2/3 inhibitor SP600125 abolishes this effect. Considering that elevated expression of bcl-xL and bcl-2 are frequent events in prostate cancer development and progression, the present studies support the use of ionizing radiation in combination with mda-7/IL-24 as a means of augmenting the therapeutic benefit of this gene in prostate cancer, particularly in the context of tumors displaying resistance to radiation therapy owing to bcl-2 family member overexpression.

Apoptosis↗

Trade-off to low-grade toxicity with conformal radiation therapy for prostate cancer on Radiation Therapy Oncology Group 9406.

The aim of this study was to evaluate and compare the rates of grade 2 or worse late effects in patients treated for prostate cancer on Radiation Therapy Oncology Group (RTOG) 9406. The authors previously have reported the results of patients treated on the first 2 dose levels of this study with respect to grade 3 or greater late toxicity. This analysis examines the incidence of grade 2 toxicity in this study. From August 1994 to September 1999, 424 patients were entered on this dose escalation trial of 3-dimensional conformal radiation therapy (3D CRT) for localized adenocarcinoma of the prostate at doses of 68.4 Gy (level I) and 73.8 Gy (level II). All radiation prescriptions were a minimum dose to a planning target volume. Patients were stratified according to clinical stage and risk of seminal vesicle invasion based on Gleason score and presenting prostate-specific antigen. Average time at risk after completion of therapy ranged from 33.1 to 40.1 months for patients treated at dose level I and 15.6 to 34.2 months for patients at dose level II. The frequency of late effects > or = grade 2 was compared with a similar group of patients treated on RTOG studies 7506 and 7706 with adjustments made for the interval from completion of therapy. The RTOG toxicity scoring scales for late effects were used. The rate of grade 3 or greater late toxicity continues to be low compared with RTOG historical controls. No grade 4 or 5 late complications were reported in any of the 406 evaluable patients during the period of observation. Interestingly, the incidence of grade 2 late toxicity was increased relative to historical controls in all groups and dose levels. In group 1, level I and group 3, level II, the increase in grade 2 complications was statistically significant; 16 complications were observed in group 1, level I when 9.2 were expected (P =.026) and 22 were observed in group 3, level II when 7.6 were expected (P <.0001). When examining all late effects > or = grade 2, there were no significant differences in the rate of late effects in both groups and both dose levels with the exception of group 1, level II. This, in combination with the statistically significant decrease in late effects > or = grade 3, suggests that in most circumstances there has been a shift of grade 3 complications to grade 2. In group 1, dose level II there was a statistically significant reduction in > or = grade 2 late effects, suggesting there was no shift from grade 3 to grade 2 in these patients. In this circumstance there may have been a global reduction in all complications or a shift to late effects less severe than grade 2. In group 2, dose level II there is a trend (P =.085) toward this same result. It is important to continue to examine late effects closely in patients treated on RTOG 9406. The primary objective of dose escalation without an increase rate of > or = grade 3 complications has been achieved. However, the reduction in grade 3 complications may have resulted in a higher incidence of grade 2 late effects. Because grade 2 late effects may have a significant impact on a patient's quality of life, it is important to reduce these complications as much as possible. Improved conformal treatment delivery with intensity-modulated radiation therapy or the use of radioprotective agents could be considered. Clinical trials should use quality-of-life measures to determine that trade-offs between severity and rates of toxicity are acceptable to patients.

Adenocarcinoma↗

The status of the seventh report in the series Biological Effects of Ionizing Radiations and a revised dosimetry for the Radiation Effects Research Foundation's A-bomb studies.

Results of a National Academies workshop and feasibility study led US Governmental agencies to request the Board on Radiation Effects Research of the National Research Council to commence a risk assessment study in 1998 as the seventh report in the series Biological Effects of Ionizing Radiations (BEIR VII). Originally targeted for completion in the autumn of 2001, the study Potential Health Effects of Exposure to Low Dose, Low-LET Ionizing Radiation was extended until the autumn of 2003 at the request of the sponsors. Two factors contributing to this decision are discussed: a revised dosimetry to update DS86 for the Radiation Effects Research Foundation's A-bomb-survivor studies and the potential for new information to become available from low-dose studies that are under way. Epidemiological and biological data since BEIR V are being considered by a BEIR VII committee composed of 17 members. The committee's statement of task is reviewed along with the major recommendations of the recent National Research Council report on the status of DS86--recommendations that are being implemented by US and Japan dosimetry working groups.

Humans↗

Radiation-induced release of transforming growth factor alpha activates the epidermal growth factor receptor and mitogen-activated protein kinase pathway in carcinoma cells, leading to increased proliferation and protection from radiation-induced cell death.

Exposure of A431 squamous and MDA-MB-231 mammary carcinoma cells to ionizing radiation has been associated with short transient increases in epidermal growth factor receptor (EGFR) tyrosine phosphorylation and activation of the mitogen-activated protein kinase (MAPK) and c-Jun NH(2)-terminal kinase (JNK) pathways. Irradiation (2 Gy) of A431 and MDA-MB-231 cells caused immediate primary activations (0-10 min) of the EGFR and the MAPK and JNK pathways, which were surprisingly followed by later prolonged secondary activations (90-240 min). Primary and secondary activation of the EGFR was abolished by molecular inhibition of EGFR function. The primary and secondary activation of the MAPK pathway was abolished by molecular inhibition of either EGFR or Ras function. In contrast, molecular inhibition of EGFR function abolished the secondary but not the primary activation of the JNK pathway. Inhibition of tumor necrosis factor alpha receptor function by use of neutralizing monoclonal antibodies blunted primary activation of the JNK pathway. Addition of a neutralizing monoclonal antibody versus transforming growth factor alpha (TGFalpha) had no effect on the primary activation of either the EGFR or the MAPK and JNK pathways after irradiation but abolished the secondary activation of EGFR, MAPK, and JNK. Irradiation of cells increased pro-TGFalpha cleavage 120-180 min after exposure. In agreement with radiation-induced release of a soluble factor, activation of the EGFR and the MAPK and JNK pathways could be induced in nonirradiated cells by the transfer of media from irradiated cells 120 min after irradiation. The ability of the transferred media to cause MAPK and JNK activation was blocked when media were incubated with a neutralizing antibody to TGFalpha. Thus radiation causes primary and secondary activation of the EGFR and the MAPK and JNK pathways in autocrine-regulated carcinoma cells. Secondary activation of the EGFR and the MAPK and JNK pathways is dependent on radiation-induced cleavage and autocrine action of TGFalpha. Neutralization of TGFalpha function by an anti-TGFalpha antibody or inhibition of MAPK function by MEK1/2 inhibitors (PD98059 and U0126) radiosensitized A431 and MDA-MB-231 cells after irradiation in apoptosis, 3-[4, 5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT), and clonogenic assays. These data demonstrate that disruption of the TGFalpha-EGFR-MAPK signaling module represents a strategy to decrease carcinoma cell growth and survival after irradiation.

Antibodies↗

Nanodosimetry, from radiation physics to radiation biology.

In view of the fact that early damage to genes and cells by ionising radiation starts with the early damage to segments of the DNA, it is a great challenge to radiation research to describe the general behaviour of ionising radiation in nanometric target volumes (nanodosimetry). After summarising basic aspects of nanodosimetry, an overview is given about its present state. As far as experimental procedures are concerned, main emphasis is laid on single-ion counting and single-electron counting methods, which use millimetric target volumes filled with a low-pressure gas to simulate nanometric target volumes at unit density. Afterwards, physical principles are discussed, which can be used to convert experimental ionisation cluster-size distributions into those caused by ionising radiation in liquid water. In the final section, possibilities are analysed of how to relate parameters derived from the probability of cluster-size formation in liquid water to parameters derived from radiobiological experiments.

Forecasting↗

Does a radiation dose-response relation exist concerning survival of patients who have soft-tissue sarcomas of the extremities? Radiation dose-response relation for soft-tissue sarcomas.

This study analyzes a single-institution experience by evaluating the impact on survival of increasing total dose of adjunctive irradiation in patients who had extremity soft-tissue sarcoma (ESTS). A retrospective review of the tumor registry at a university medical center from January 1984 through December 1992 yielded a total of 59 surgical patients of ESTS. With follow-up ranging from 30 to 135 months (median, 65 months), the 2-, 5-, and 8-year overall and disease-free survival for all patients was 86%, 71%, 58% and 76%, 70%, 56%, respectively. Multivariate analyses using the Cox proportional hazards model revealed that total radiation dose (p = 0.02), American Joint Committee on Cancer stage (p = 0.04), and tumor size (p = 0.006) were all significant prognostic factors of overall survival; however, only tumor size was predictive of disease-free survival (p = 0.02). When the effect of tumor size and disease stage were controlled in the Cox model, a dose-response curve between increasing total radiation dose and improved overall patient survival was indicated. This study demonstrates the significance of tumor size on predicting both overall and disease-free survival in patients who have soft-tissue sarcomas of the extremity. It also suggests, however, that a radiation dose-response relation may exist for overall survival. Future investigations should consider evaluating the minimal total radiation dose needed to optimize patient survival after limb-sparing surgery.

Adolescent↗

Determining and reporting fetal radiation exposure from diagnostic radiation.

Pregnant women are sometimes exposed to diagnostic ionizing radiation for any number of legitimate medical reasons. When this occurs, it is important to perform an accurate fetal dose estimate using standard methodologies as quickly as possible and to convey this information to the woman's physician, along with a summary of appropriate published medical guidelines. This will provide the physician and the patient with the information necessary to make an informed decision regarding the potential impact of this radiation exposure on the pregnancy. At the same time, it is important to recognize that not all pregnancies end well, and there is a finite chance that legal action could ensue because of this, even if radiation exposure was negligible. For this reason, it is also important to make sure that standard, accepted protocols are followed in calculating radiation exposure and the health physicist provide advice only in his or her areas of competence.

Diagnostic Imaging↗

Simple method to demonstrate radiation-inducible radiation resistance in microbial cells.

A simple method for detection of radiation-inducible radiation resistance was developed by irradiating aliquots (0.01 ml) of cell suspension on agar plates. Part of each experimental plate was subjected to an induction treatment, and subsequent radiation resistance was compared with that of untreated cells on the same plate. The UV radiation resistance of a Micrococcus sp. was increased approximately 1.6 times by an induction treatment. This simple procedure of irradiating cells in a "fixed" position on agar avoided washing, centrifugation, and cell enumeration required in traditional methods.

Agar↗

Neutron radiation can activate K-ras via a point mutation in codon 146 and induces a different spectrum of ras mutations than does gamma radiation.

Neutron radiation is known to produce tumors in animals and cause cell transformation. We have developed a protocol to efficiently induce thymic lymphomas in RF/J mice by a single acute dose of neutron irradiation. Activated ras genes were detected in 17% (4 of 24) of the tumors analyzed. One of the tumors contained a K-ras gene activated by a point mutation in codon 146. Activating ras mutations at position 146 have not been previously detected in any known human or animal tumors. The spectrum of ras mutations detected in neutron radiation-induced thymic lymphomas was different from that seen in thymic lymphomas induced by gamma radiation in the same strain of mice. These results may have important implications for the mechanisms by which different types of radiation damage DNA.

Animals↗

Phase I study to determine the maximum-tolerated dose of radiation in standard daily and hyperfractionated-accelerated twice-daily radiation schedules with concurrent chemotherapy for limited-stage small-cell lung cancer.

PURPOSE: An improvement in radiation dose schedule is necessary to increase local tumor control and survival in limited-stage small-cell lung cancer. The goal of this study was to determine the maximum-tolerated dose (MTD) of radiation (RT) in both standard daily and hyperfractionated-accelerated (HA) twice-daily RT schedules in concurrent chemoradiation. METHODS: The study design consisted of a sequential dose escalation in both daily and HA twice-daily RT regimens. RT dose to the initial volume was kept at 40 to 40.5 Gy, while it was gradually increased to the boost volume by adding a 7% to 11 % increment of total dose to subsequent cohorts. The MTD was defined as the radiation dose level at one cohort below that which resulted in more than 33% of patients experiencing grade > or = 4 acute esophagitis and/or grade > or = 3 pulmonary toxicity. The study plan included nine cohorts, five on HA twice-daily and four on daily regimens for the dose escalation. Chemotherapy consisted of three cycles of cisplatin 33 mg/m2/d on days 1 to 3 over 30 minutes, cyclophosphamide 500 mg/m2 on day 1 intravenously (IV) over 1 hour, and etoposide 80 mg/m2/d on days 1 to 3 over 1 hour every 3 weeks (PCE) and two cycles of PE. RT was started at the initiation of the fourth cycle of chemotherapy. RESULTS: Fifty patients were enrolled onto the study. The median age was 60 years (range, 38-79), sex ratio 2.3:1 for male to female, weight loss less than 5% in 73%, and performance score 0 to 1 in 94% and 2 in 6% of patients. In HA twice-daily RT, grade > or = 4 acute esophagitis was noted in two of five (40%), two of seven (29%), four of six (67%), and five of six patients (86%) at 50 (1.25 Gy twice daily), 45, 50, and 55.5 Gy in 1.5 Gy twice daily, 5 d/wk, respectively. Grade > or = 3 pulmonary toxicity was not seen in any of these 24 patients. Therefore, the MTD for HA twice-daily RT was judged to be 45 Gy in 30 fractions over 3 weeks. In daily RT, grade > or = 4 acute esophagitis was noted in zero of four, zero of four, one of five (20%), and two of six patients (33%) at 56, 60, 66, and 70 Gy on a schedule of 2 Gy per fraction per day, five fractions per week. Grade > or = 3 pneumonitis was not observed in any of the 19 patients. Thus, the MTD for daily RT was judged to be at least 70 Gy in 35 fractions over 7 weeks. Grade 4 granulocytopenia and thrombocytopenia were observed in 53% and 6% of patients, respectively, during the first three cycles of PCE. During chemotherapy cycles 4 to 5, grade 4 granulocytopenia and thrombocytopenia were noted in 43% and 29% of patients at 45 Gy in 30 fractions over 3 weeks (MTD) by HA twice-daily RT and 50% and 17% at 70 Gy in 35 fractions over 7 weeks (MTD) by daily RT, respectively. The overall tumor response consisted of complete remission (CR) in 51% (24 of 47), partial remission (PR) in 38% (1 8 of 47), and stable disease in 2% (one of 47). The median survival time of all patients was 24.4 months and 2- and 3-year survival rates were 53% and 28%, respectively. With regard to the different radiation schedules, 2- and 3-year survival rates were 52% and 25% for the HA twice-daily and 54% and 35% for the daily RT cohorts. CONCLUSION: The MTD of HA twice-daily RT was determined to be 45 Gy in 30 fractions over 3 weeks, while it was judged to be at least 70 Gy in 35 fractions over 7 weeks for daily RT. A phase III randomized trial to compare standard daily RT with HA twice-daily RT at their MTD for local tumor control and survival would be a sensible research in searching for a more effective RT dose-schedule than those that are being used currently.

Adult↗

Cisplatin, ifosfamide, oral etoposide, and concurrent accelerated hyperfractionated thoracic radiation for patients with limited small-cell lung carcinoma: results of radiation therapy oncology group trial 93-12.

PURPOSE: The combination of cisplatin, ifosfamide, and oral etoposide (PIEo) given concurrently with accelerated hyperfractionated thoracic radiation was studied in patients with limited small-cell lung cancer in a phase II trial to assess response, survival, and toxicity. PATIENTS AND METHODS: Sixty-seven patients were accrued between March 1994 and April 1996. Chemotherapy doses were cisplatin 20 mg/m(2) and ifosfamide 1,200 mg/m(2) on days 1 to 3 and etoposide 40 mg/m(2) administered orally days 1 through 14. Radiation consisted of accelerated hyperfractionated thoracic radiation (AHTRT) 1.5 Gy bid x 30 fractions (total 45 Gy) days 1 through 19, concurrent with cycle 1 of chemotherapy. Three additional cycles of chemotherapy were given every 4 weeks after completion of chemoradiation. Prophylactic cranial radiation (25 Gy in 10 fractions) was offered to patients for whom complete response (CR) after completion of chemotherapy was achieved. RESULTS: An overall objective response rate of 78% (41 CRs [67%] and seven partial responses [11%]) was seen in 61 patients whose disease response could be evaluated. Median progression-free and overall survival estimates were 12.7 and 23.7 months, respectively. Two- and 3-year survival rates were estimated at 50% and 39%, respectively. Major toxic effects included grade 4 granulocytopenia in 34 (55%), grade 4 thrombocytopenia in 16 (26%), grade 3 to 5 fever/infection in six (10%; with one death resulting from sepsis), and grade 3/4 esophagitis in 27 patients (43%). Other nonhematologic toxic greater than grade 2 occurred in 11 patients (18%). CONCLUSION: Relative to conventional etoposide/cisplatin and concurrent AHTRT, chemoradiation with PIEo produced similar median and 2-year survival rates and a higher rate of acute esophageal toxicity. However, the locoregional control rate with a minimum follow-up of 2 years is excellent at 80%. It is conceivable that longer follow-up will prove this regimen more promising. Research efforts should focus on other methods to improve disease control in all potential sites of recurrence.

Administration, Oral↗

Phase III Trial of an emulsion containing trolamine for the prevention of radiation dermatitis in patients with advanced squamous cell carcinoma of the head and neck: results of Radiation Therapy Oncology Group Trial 99-13.

PURPOSE: This multicentered phase III trial was designed to compare an emulsion containing trolamine against the usual supportive care within each participating institution for patients with head and neck cancer undergoing radiation therapy. PATIENTS AND METHODS: Patients with biopsy-proven squamous cell carcinoma of the oral cavity, oropharynx, hypopharynx, or larynx were randomly assigned to one of the following treatments: prophylactic trolamine emulsion, interventional trolamine emulsion, or declared institutional preference. The primary outcome was the reduction in grade 2 or higher skin toxicity, as per National Cancer Institute Common Toxicity Criteria version 2.0. Secondary outcomes included patient-reported quality of life (QOL). RESULTS: From October 2000 to April 2002, 547 patients from 51 institutions were entered onto the trial. The average age was 59 years. Patients were predominately male (79%) and most continued to use tobacco products (52%). The rates of grade 2 or higher radiation dermatitis were 79%, 77%, and 79% in the prophylactic, interventional, and institutional preference arms of the study, respectively. No significant differences in QOL were found. CONCLUSION: The results of this trial demonstrate no advantage for the use of trolamine in reducing the incidence of grade 2 or higher radiation dermatitis or improving patient-reported QOL. The use of 15 different local standards of care highlights the need to continue research that will result in evidence-based recommendations to reduce the burden of radiation dermatitis.

Carcinoma, Squamous Cell↗

Studies on chemical protectors against radiation. XXXV. Effects of radioprotective Chinese traditional medicines on radiation-induced lipid peroxidation in vivo and in vitro.

The fluctuation of lipid peroxidation (LP) in 9 tissues was investigated in mice for 7 d after whole-body X-irradiation with a lethal dose of bone marrow death. LP increased significantly in bone marrow, thymus, spleen and liver following irradiation, and slightly in brain and testis, but not in blood plasma, submaxillary gland or kidney. The effects of 7 radioprotective Chinese traditional medicines (CTMs) and cysteamine (MEA) on the radiation-induced LP in 4 tissues were studied by i.p. injection before or after irradiation and their LP content in tissues was measured 2 d after irradiation. Most CTMs showed significant inhibition of radiation-induced LP in bone marrow and liver, especially when injected prior to irradiation. Some CTMs also showed such inhibition in spleen. MEA only inhibited the increase of LP in liver when injected before irradiation, but enhanced the increase of LP in spleen. None of these radioprotectors including MEA was recognized to inhibit radiation-induced LP in thymus. The in vitro experiments were carried out using mouse liver microsomal suspensions (MS). The MS were prepared from normal (non-irradiated) mice. Each of the 8 radioprotectors was added to MS before or after irradiation and then post-irradiation-incubated at 37 degrees C. All markedly inhibited radiation-induced LP if added before irradiation, but were slightly less effective if added after.

Animals↗

[Studies on chemical protectors against radiation. XXXIII. Protective mechanisms of various compounds against skin injury induced by radiation].

The radiation protective mechanisms on skin injury induced by soft X-irradiation were investigated by use of various radiation protective agents such as sulfur compounds (MEA, MEG, thiourea), nucleic acid constitutional compounds (adenosine, inosine), antioxidative compounds (sesamol, ferulic acid, ascorbic acid), crude drugs (Rosae Fructus, Anemarrhenae Rhizoma, Trapae Fructus, Forsythiae Fructus, Aloe arborescens). Scavenge action of activated oxygen, inhibitory effect of lipid peroxidation, induction of antioxidative protein and protective effect against damage of deoxyribonucleic acid and superoxide dismutase by X-irradiation were evaluated as the radiation protective mechanisms, and relationship between these results and protective effect of skin injury induced by radiation was studied.

Adenosine↗