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At least 145 records · Page 8Linked to original sources
PubMed1993

Lipid peroxidation does not appear to be a factor in late radiation injury of the cervical spinal cord of rats.

PURPOSE: We tested the role of lipid peroxidation in the demyelination and white matter necrosis associated with radiation injury of the central nervous system. METHODS AND MATERIALS: We irradiated the cervical spinal cords of female F344 rats (23 Gy) and assayed for the accumulation of the peroxidation byproducts malondialdehyde and hydroxyeicosatetraenoic acids, and for the consumption of the endogenous free radical scavengers vitamins E and C. We further tested the role of lipid peroxidation in radiation injury of the central nervous system by determining the sensitivity of the cervical spinal cord to radiation in rats on diets containing deficient, normal, and supplemental levels of the antioxidant vitamin E. Rats were placed on these diets at 4 weeks of age and irradiated (18.5-21.5 Gy) 16 weeks later. RESULTS: During the 5 months between irradiation and the onset of paralysis, no accumulation of peroxidation byproducts or consumption of endogenous scavengers was seen in the cervical spinal cords of the irradiated rats. The cervical spinal cords of some of the rats placed on the diets with deficient, normal, and supplemental levels of vitamin E were analyzed at the time of irradiation and contained 197 +/- 57, 501 +/- 19, and 717 +/- 35 pmol vitamin E/mg protein, respectively. Despite the statistical differences in these levels, the radiation sensitivity of the cervical spinal cord (ED50 for white matter necrosis) in rats receiving the three diets was not different (20.4, 20.7, and 20.6 Gy). CONCLUSION: These data do not support a role for free radical-induced lipid peroxidation in the white matter damage seen in radiation injury of the central nervous system.

Animals↗
PubMed1995

Late radiation injury to muscle and peripheral nerves.

Late radiation injury to muscles and peripheral nerves is infrequently observed. However, the success of radiation oncology has led to longer patient survival, providing a greater opportunity for late effects to develop, increase in severity and, possibly, impact the quality of life of the patient. In addition, when radiation therapy is combined with surgery and/or chemotherapy, the risk of late complications is likely to increase. It is clear that the incidence of complications involving muscles and nerves increases with time following radiation. The influence of volume has yet to be determined; however, an increased volume is likely to increase the risk of injury to muscles and nerves. Experimental and clinical studies have indicated that the alpha/beta ratio for muscle is approximately 4 Gy and, possibly, 2 Gy for peripheral nerve, indicating the great influence of fractionation on response of these tissues. This is of concern for intraoperative radiation therapy, and for high dose rate brachytherapy. This review of clinical and experimental data discusses the response of muscle and nerves late after radiation therapy. A grading system has been proposed and endpoints suggested.

Humans↗
PubMed1999

Protective effects of 5,6,7,8-tetrahydroneopterin against X-ray radiation injury in mice.

The protective effects of 5,6,7,8-tetrahydroneopterin (NH4) against radiation injury in mice were studied. (C57BL/6xA/J)F1 (B6A) mice received a single whole-body irradiation dose of 200, 400, 700 or 800 cGy of X-rays. NH4 (30 mg/kg body weight) or phosphate-buffered saline (PBS) was injected intraperitoneally into irradiated mice 10 min before and after the irradiation and again after 6 h. All mice which received the 800 cGy radiation+PBS died between 8 and 11 days after the treatment. In contrast, those which also received NH4 demonstrated a significantly prolonged survival time and 40% lived more than 5 months. Total numbers of thymocytes and spleen cells on day 5 post-irradiation were dramatically reduced in line with the radiation dose. The survival was significantly enhanced by NH4 in treated mice. The proliferation of spleen cells in mice stimulated by concanavalin A (Con A) or lipopolysaccharide (LPS) was also greater in NH4 treated mice. The immune response of survivors 5 months after 800 cGy+NH4 treatments, against Con A, LPS, allogenic mouse, and sheep red blood cells had essentially recovered to the levels of normal mice. These results indicate that NH4 had an important role in modifying radiation injury.

Animals↗
PubMed2004

[Effect of ligustrazine on expressions of basic fibroblast growth factor and its receptor in bone marrow of mice with acute radiation injury].

OBJECTIVE: To study the expressions of basic fibroblast growth factor (bFGF) and its receptor (bFGFR) in bone marrow of mice with acute radiation injury, and to evaluate the effect of Ligustrazine (Lt) on them. METHODS: Fifty-six Kunming mice of clean grade were randomly divided into 3 groups, the normal group, the control group and the Lt group. Mice in the latter two groups were once homogeneously systemic irradiated with 6.0 Gy of 60Co, with the absorption dose rate of 0.56 Gy/min, then treated with saline (0.2 ml/mice) or Lt (2 mg/mice) respectively, twice a day through gastrogavage for successive 13 days. Mice were sacrificed in batch on the 3rd, 7th and 14th day by cervical dislocation to collect the bilateral femoral bone marrow for preparing bone marrow mono-nuclear cell (BMMNC) suspension. The bFGFR expression on surface of BMMNC was determined by flow cytometry; and the bFGF expression level in one side of femoral bone marrow tissue was detected by immunohistochemistry with SABC-AP assay. RESULTS: The bFGF expression in bone marrow of mice on the 3rd, 7th and 14th day after acute radiation injury all were significantly lower than that of the normal mice (P < 0.05 or P < 0.01). The expressions of bFGF and bFGFR in the Lt group detected were significantly higher than that in the control group detected at the corresponding time points (P < 0.05 or P < 0.01). CONCLUSION: By way of enhancing bFGF expression in bone marrow and bFGFR expression on surface of BMMNC to accelerate the repairing of homopoietic micro-environment in bone marrow might be one of the mechanisms of Lt in promoting hemopoietic function reconstitution after acute radiation injury.

Animals↗
PubMedDate not supplied

Surgical treatment of severe late radiation injury to the bowel: a retrospective analysis of 83 cases.

BACKGROUND/AIMS: The aim of this study was to determine the best surgical approach for the treatment of late radiation injury to the bowel. METHODOLOGY: Clinical and follow-up charts of 83 patients operated in our institution for late radiation injury to the bowel were retrospectively reviewed. The type of operation (resection-anastomosis or bypass) mortality, postoperative complications and reoperation rate were recorded. Seventy-six underwent resection with immediate anastomosis. A bypass or viscerolysis was performed in only 7 patients. RESULTS: Postoperative mortality was 2.4%, morbidity was 23. Twenty-seven patients underwent further surgery; early reoperation (within 1 month) was necessary in 12 (morbidity 41%). A late reoperation has been performed in 15 patients (no mortality, morbidity 53.5%). CONCLUSIONS: From the results of our study it can be concluded that resection with immediate anastomosis for late radiation injury to the bowel is safe and should be the first option for these patients.

Adult↗
PubMed2005

Differentiation between brain tumor recurrence and radiation injury using MR spectroscopy.

OBJECTIVE: The purpose of our study was to explore the feasibility and utility of 2D chemical shift imaging (CSI) MR spectroscopy in the evaluation of new areas of contrast enhancement at the site of a previously treated brain neoplasm. MATERIALS AND METHODS: Two-dimensional CSI (point-resolved spectroscopy sequence [PRESS]; TR/TE, 1,500/144) was performed in 29 consecutive patients (4-54 years old; mean age, 34 years) who had a new contrast-enhancing lesion in the vicinity of a previously diagnosed and treated brain neoplasm. Clinical and imaging follow-up, and histopathology in 16 patients, were used as indicators of the identity of a lesion. RESULTS: Diagnostic-quality spectra were obtained in 97% of the patients. The Cho/Cr (choline/creatine) and Cho/NAA (choline/N-acetyl aspartate) ratios were significantly higher, and the NAA/Cr ratios significantly lower, in tumor than in radiation injury (all three differences, p < 0.0001). The Cho/Cr and Cho/NAA ratios were significantly higher in radiation injury than in normal-appearing white matter (p < 0.0003 and p < 0.0001, respectively), whereas NAA/Cr ratios were not different (p = 0.075). Mean Cho/Cr ratios were 2.52 for tumor, 1.57 for radiation injury, and 1.14 for normal-appearing white matter. Mean Cho/NAA ratios were 3.48, 1.31, 0.79, and mean NAA/Cr ratios were 0.79, 1.22, and 1.38, respectively. When values greater than 1.8 for either Cho/Cr or Cho/NAA ratios were considered evidence of tumor, 27 of 28 patients could be correctly classified. CONCLUSION: Two-dimensional CSI MR spectroscopy can differentiate tumor from radiation injury in patients with recurrent contrast-enhancing intracranial lesions. In these lesions, the Cho/NAA and Cho/Cr ratios may be the best numeric discriminators.

Adolescent↗
PubMed2000

Treatment-time-dependence models of early and delayed radiation injury in rat small intestine.

BACKGROUND: The present study modeled data from a large series of experiments originally designed to investigate the influence of time, dose, and fractionation on early and late pathologic endpoints in rat small intestine after localized irradiation. The objective was to obtain satisfactory descriptions of the regenerative response to injury together with the possible relationships between early and late endpoints. METHODS: Two- and 26-week pathologic radiation injury data in groups of Sprague-Dawley rats irradiated with 27 different fractionation schedules were modeled using the incomplete repair (IR) version of the linear-quadratic model with or without various time correction models. The following time correction models were tested: (1) No time correction; (2) A simple exponential (SE) regenerative response beginning at an arbitrary time after starting treatment; and (3) A bi-exponential response with its commencement linked to accumulated cellular depletion and fraction size (the 'intelligent response model' [INTR]). Goodness of fit of the various models was assessed by correlating the predicted biological effective dose for each dose group with the observed radiation injury score. RESULTS: (1) The incomplete repair model without time correction did not provide a satisfactory description of either the 2- or 26-week data. (2) The models using SE time correction performed better, providing modest descriptions of the data. (3) The INTR model provided reasonable descriptions of both the 2- and 26-week data, confirming a treatment time dependence of both early and late pathological endpoints. (4) The most satisfactory descriptions of the data by the INTR model were obtained when the regenerative response was assumed to cease 2 weeks after irradiation rather than at the end of irradiation. A fraction-size-dependent delay of the regenerative response was also suggested in the best fitting models. (5) Late endpoints were associated with low-fractionation sensitivity and treatment-time dependence even in animal groups that exhibited minimal early mucosal reactions. CONCLUSION: Radiation injury scores in this rat small intestinal experimental model cannot be adequately described without time correction. 'Consequential' mechanisms contribute to the development of late effects, even in animals that do not develop severe early mucosal injuries. The initiation of the regenerative response is subject to a fraction-size-dependent mitotic delay and is linked to the level of accumulated cellular depletion. The response does not cease at the end of therapy but probably continues until maximal healing has taken place.

Animals↗
PubMed2006

Outcomes of surgery for resection of regions of symptomatic radiation injury after stereotactic radiosurgery for arteriovenous malformations.

OBJECTIVE: Although radiation injury after stereotactic radiosurgery (SRS), including radiation necrosis (RN), is often treated with surgical resection, detailed outcome data are lacking after resection of symptomatic radiation-injured regions with imaging characteristics suspicious for RN after SRS for arteriovenous malformations (AVM). We present outcomes in seven such patients. METHODS: We conducted a retrospective chart review of seven patients with AVMs of Spetzler-Martin Grades II (n = 1), III (n = 2), and IV (n = 4) who underwent helium ion, proton beam, or gamma knife SRS and required resection of RN-suspicious tissue 1 to 24 months after post-SRS symptom onset. Postoperative outcomes included Karnofsky Performance Scale (KPS) score and time to symptomatic improvement. RESULTS: Symptomatic improvement required at least 9 months in the three patients with large regions suspicious for RN (>or=4 cm), whereas of four patients with smaller regions (<4 cm), three showed improvement within 2 months (P < 0.05). The remaining patient, who showed no benefit, underwent resection 2 years after the onset of RN symptoms (compared with <or= 8 mo for the other six patients). Surgery improved KPS scores in four patients with a preoperative KPS score of 50 or lower, but not in three patients with preoperative KPS scores greater than 70 (P < 0.05). Outcomes were not consistently associated with AVM size or location, SRS treatment volume or dose, associated aneurysm, or residual AVM. CONCLUSION: After SRS for AVMs, resection of symptomatic RN-suspicious tissue areas is beneficial in reversing neurological deficits and improving KPS scores in selected patients. Times to improvement were longer when larger areas were resected. Delaying such surgery after symptom onset may negatively affect improvement.

Adult↗
PubMedDate not supplied

[Medical-prophylactic properties of the low-molecular-weight chitosan at environmental radiation injury].

The possibility of the successful modification of radiation injury by chitosan with low molecular weight (10 kDa) has been established under experimental conditions. The survival of mice increased up to 72.7 and 44.7% respectively at intravenous and intramuscular injection 30 min before gamma-irradiation with a dose 8 Gy (LD97). In guinea pigs the effect was 50-52.6% at intravenous and 40% at intramuscular administration 1-3 h after irradiation with a dose 5 Gy (LD90). Radioprotective efficiency of 10 kDa chitosan is close to that of high-molecular-weight (65-70 kDa) preceding (medicine RS-10 and RS-11).

Animals↗
PubMed2004

[Study on human amniotic membrane loaded with marrow mesenchymal stem cells and epidermis cells in promoting healing of wound combined with radiation injury].

OBJECTIVE: To investigate the results of human amniotic membrane (HAM) which are loaded with marrow mesenchymal stem cells (MSCs) and epidermis cells in treating full-thickness skin defect combined with radiation injury. METHODS: Eight minipigs were used in this study. Three round full-thickness wounds (phi3.67cm), which combined with radiation injury, were created on the dorsum of each side close to the vertebral column in each animal. Among 48 wounds, 24 left side wounds were treated with HAM loaded with MSCs and epidermis cells as experimental group (group A), 16 right side wounds with simple HAM (HAM group, group B) and 8 right side wounds with oil gauze as control (group C). The granulation tissue, reepithelization and wound area were observed after 1,2 and 3 weeks. Immunohistochemistry was performed using vWF as a marker for blood vessels. Image analysis was employed to test new area of wound at different interval time and healing rate of wound. RESULTS: The healing time of group A was 6 to 7 days faster than that of group C and 5 to 6 days fister than that of group B. After 15-17 days of graft, there were significant differences in new area of wound and healing rate between group A and groups B, C (P < 0. 01). New epidermis fully covered whole wound surface in group A, and their granulation tissue, which contained a lot of vWF, fibroblasts, capillaries and collagen, grew well. Many inflammatory cells still were seen in groups B and C, and their contents of vWF, fibroblasts, capillaries and collagen in granulation tissue were smaller than that in group A. CONCLUSION: The graft of HAM loaded with MSCs and epidermis cells played an effective role in promoting healing of wound combined radiation injury with high quality.

Amnion↗
PubMed1977

[Surgical management of left colon and rectal radiation injuries (author's transl)].

A. First of all, we can affirm after the analysis of 132 records: the predominance of gynecologic cancers and the frequent responsibility of medical associations in the determinism of advanced radiation injuries of colon and rectum; the typically variable appearence of these injuries with an usual delay going from 6 months to a year and limits from 2 months to 35 years; the difficulty of diagnosis between radiation injurie and recurrence of cancer especially in case of fistula and the severe forecost in case of cancer radiation injurie association. B. The surgical management exist only for non-indications and failures of medical treatment; the one stage resection with end to end anastomosis will be made exclusively on advanced, therefore non evolving and limited injuries; in most cases, the multiple stage resection must be preferred: first derivation in selected part (sigmoid or transverse colon) and secondary resection in healthy area; as regards the closure of colostomy, it must never occur before a 6 months delay and anastomosis radiologic check.

Abdominal Neoplasms↗
PubMedDate not supplied

[Possible modification of radiation injury using radio frequency electromagnetic radiation].

The possibility of radioprotective action of electromagnetic fields and radiations in radiofrequency range have been considered. It has been shown that the EMF and EMR effects depend on parameters of acting field. It is necessary to establish biophysical and biochemical ways and mechanisms of EMF and EMR action for effective use of radioemissions as radioprotectors.

Animals↗