| 1. |
- Naylor, Andrew Stuart, 1977, et al.
(författare)
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Voluntary running rescues adult hippocampal neurogenesis after irradiation of the young mouse brain.
- 2008
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 1091-6490. ; 105:38, s. 14632-7
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Tidskriftsartikel (refereegranskat)abstract
- Cranial radiation therapy is commonly used in the treatment of childhood cancers. It is associated with cognitive impairments tentatively linked to the hippocampus, a neurogenic region of the brain important in memory function and learning. Hippocampal neurogenesis is positively regulated by voluntary exercise, which is also known to improve hippocampal-dependent cognitive functions. In this work, we irradiated the brains of C57/BL6 mice on postnatal day 9 and evaluated both the acute effects of irradiation and the effects of voluntary running on hippocampal neurogenesis and behavior 3 months after irradiation. Voluntary running significantly restored precursor cell and neurogenesis levels after a clinically relevant, moderate dose of irradiation. We also found that irradiation perturbed the structural integration of immature neurons in the hippocampus and that this was reversed by voluntary exercise. Furthermore, irradiation-induced behavior alterations observed in the open-field test were ameliorated. Together, these results clearly demonstrate the usefulness of physical exercise for functional and structural recovery from radiation-induced injury to the juvenile brain, and they suggest that exercise should be evaluated in rehabilitation therapy of childhood cancer survivors.
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| 2. |
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| 3. |
- Alevronta, Eleftheria, et al.
(författare)
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Dose-response relationships of intestinal organs and excessive mucus discharge after gynaecological radiotherapy
- 2021
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203 .- 1932-6203. ; 16:4 April
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Tidskriftsartikel (refereegranskat)abstract
- Background The study aims to determine possible dose-volume response relationships between the rectum, sigmoid colon and small intestine and the ‘excessive mucus discharge’ syndrome after pelvic radiotherapy for gynaecological cancer. Methods and materials From a larger cohort, 98 gynaecological cancer survivors were included in this study. These survivors, who were followed for 2 to 14 years, received external beam radiation therapy but not brachytherapy and not did not have stoma. Thirteen of the 98 developed excessive mucus discharge syndrome. Three self-assessed symptoms were weighted together to produce a score interpreted as ‘excessive mucus discharge’ syndrome based on the factor loadings from factor analysis. The dose-volume histograms (DVHs) for rectum, sigmoid colon, small intestine for each survivor were exported from the treatment planning systems. The dose-volume response relationships for excessive mucus discharge and each organ at risk were estimated by fitting the data to the Probit, RS, LKB and gEUD models. Results The small intestine was found to have steep dose-response curves, having estimated dose-response parameters: γ : 1.28, 1.23, 1.32, D : 61.6, 63.1, 60.2 for Probit, RS and LKB respectively. The sigmoid colon (AUC: 0.68) and the small intestine (AUC: 0.65) had the highest AUC values. For the small intestine, the DVHs for survivors with and without excessive mucus discharge were well separated for low to intermediate doses; this was not true for the sigmoid colon. Based on all results, we interpret the results for the small intestine to reflect a relevant link. Conclusion An association was found between the mean dose to the small intestine and the occurrence of ‘excessive mucus discharge’. When trying to reduce and even eliminate the incidence of ‘excessive mucus discharge’, it would be useful and important to separately delineate the small intestine and implement the dose-response estimations reported in the study.
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| 4. |
- Alevronta, Eleftheria, et al.
(författare)
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Dose-response relationships of the sigmoid for urgency syndrome after gynecological radiotherapy.
- 2018
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Ingår i: Acta oncologica (Stockholm, Sweden). - 1651-226X .- 0284-186X. ; 57:10, s. 1352-1358
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Tidskriftsartikel (refereegranskat)abstract
- To find out what organs and doses are most relevant for 'radiation-induced urgency syndrome' in order to derive the corresponding dose-response relationships as an aid for avoiding the syndrome in the future.From a larger group of gynecological cancer survivors followed-up 2-14 years, we identified 98 whom had undergone external beam radiation therapy but not brachytherapy and not having a stoma. Of those survivors, 24 developed urgency syndrome. Based on the loading factor from a factor analysis, and symptom frequency, 15 symptoms were weighted together to a score interpreted as the intensity of radiation-induced urgency symptom. On reactivated dose plans, we contoured the small intestine, sigmoid colon and the rectum (separate from the anal-sphincter region) and we exported the dose-volume histograms for each survivor. Dose-response relationships from respective risk organ and urgency syndrome were estimated by fitting the data to the Probit, RS, LKB and gEUD models.The rectum and sigmoid colon have steep dose-response relationships for urgency syndrome for Probit, RS and LKB. The dose-response parameters for the rectum were D50: 51.3, 51.4, and 51.3 Gy, γ50 = 1.19 for all models, s was 7.0e-09 for RS and n was 9.9 × 107 for LKB. For Sigmoid colon, D50 were 51.6, 51.6, and 51.5 Gy, γ50 were 1.20, 1.25, and 1.27, s was 2.8 for RS and n was 0.079 for LKB.Primarily the dose to sigmoid colon as well as the rectum is related to urgency syndrome among gynecological cancer survivors. Separate delineation of the rectum and sigmoid colon in order to incorporate the dose-response results may aid in reduction of the incidence of the urgency syndrome.
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| 5. |
- Alin, Rebecca, 1989, et al.
(författare)
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A Preparatory Study for a Randomized Controlled Trial of Dietary Fiber Intake During Adult Pelvic Radiotherapy
- 2021
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Ingår i: Frontiers in Nutrition. - : Frontiers Media SA. - 2296-861X. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Background: Patients undergoing pelvic radiotherapy are often advised to omit fiber-rich foods from their diet to reduce the adverse effects of treatment. Scientific evidence supporting this recommendation is lacking, and recent studies on animals and humans have suggested that there is a beneficial effect of dietary fiber for the alleviation of symptoms. Randomized controlled studies on dietary fiber intake during pelvic radiotherapy of sufficient size and duration are needed. As preparation for such a large-scale study, we evaluated the feasibility, compliance, participation rate, and logistics and report our findings here in this preparatory study. Methods: In this preparatory study of a fiber intervention trial, Swedish gynecological cancer patients scheduled for radiotherapy were recruited between January 2019 and August 2020. During the intervention, the participants filled out questionnaires and used an application. They also consumed a fiber supplement at first in powder form, later in capsules. Blood- and fecal samples were collected. The study is registered in clinicaltrials.gov (https://clinicaltrials.gov/ct2/show/NCT04534075?cond=fidura&draw=2&rank=1). Results: Among 136 approached patients, 57 started the study and the participation rate for primary outcomes was 63% (third blood sample) and 65% (third questionnaire). Barely half of the participants provided fecal samples. Providing concise and relevant information to the patients at the right time was crucial in getting them to participate and stay in the study. The most common reasons for declining participation or dropping out were the expected burden of radiotherapy or acute side effects. Tailoring the ambition level to each patient concerning the collection of data beyond the primary endpoints was an important strategy to keep the dropout rate at an acceptable level. Using capsules rather than psyllium in powder form made it much easier to document intake and to create a control group. During the course of the preparatory study, we improved the logistics and for the last 12 participants included, the participation rate was 100% for the earliest primary outcome. Conclusion: A variety of adjustments in this preparatory study resulted in an improved participation rate, which allowed us to set a final protocol and proceed with the main study.
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| 6. |
- Boström, Martina, et al.
(författare)
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A role for endothelial cells in radiation-induced inflammation
- 2018
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Ingår i: International Journal of Radiation Biology. - : Informa UK Limited. - 0955-3002 .- 1362-3095. ; 94:3, s. 259-271
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To unravel the role of the vasculature in radiation-induced brain tissue damage.Materials and methods: Postnatal day 14 mice received a single dose of 10Gy cranial irradiation and were sacrificed 6h, 24h or 7 days post-irradiation. Endothelial cells were isolated from the hippocampus and cerebellum using fluorescence-activated cell sorting, followed by cell cycle analysis and gene expression profiling.Results: Flow cytometric analysis revealed that irradiation increased the percentage of endothelial cells, relative to the whole cell population in both the hippocampus and the cerebellum. This change in cell distribution indicates that other cell types are more susceptible to irradiation-induced cell death, compared to endothelial cells. This was supported by data showing that genes involved in endothelial cell-specific apoptosis (e.g. Smpd1) were not induced at any time point investigated but that genes involved in cell-cycle arrest (e.g. Cdkn1a) were upregulated at all investigated time points, indicating endothelial cell repair. Inflammation-related genes, on the other hand, were strongly induced, such as Ccl2, Ccl11 and Il6.Conclusions: We conclude that endothelial cells are relatively resistant to ionizing radiation but that they play an active, hitherto unknown, role in the inflammatory response after irradiation. In the current study, this was shown in both the hippocampus, where neurogenesis and extensive cell death after irradiation occurs, and in the cerebellum, where neurogenesis no longer occurs at this developmental age.
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| 7. |
- Bull, Cecilia, 1977, et al.
(författare)
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A novel mouse model of radiation-induced cancer survivorship diseases of the gut
- 2017
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Ingår i: American journal of physiology. Gastrointestinal and liver physiology. - : American Physiological Society. - 1522-1547 .- 0193-1857. ; 313:5, s. G456-G466
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Tidskriftsartikel (refereegranskat)abstract
- A deeper understanding of the radiation-induced pathophysiological processes that develop in the gut is imperative to prevent, alleviate, or eliminate cancer survivorship diseases after radiotherapy to the pelvic area. Most rodent models of high-dose gastrointestinal radiation injury are limited by high mortality. We therefore established a model that allows for the delivering of radiation in fractions at high doses while maintaining long-term survival. Adult male C57/BL6 mice were exposed to small-field irradiation, restricted to 1.5 cm of the colorectum using a linear accelerator. Each mouse received 6 or 8 Gy, two times daily in 12-h intervals in two, three, or four fractions. Acute cell death was examined at 4.5 h postirradiation and histological changes at 6 wk postirradiation. Another group was given four fractions of 8 Gy and followed over time for development of visible symptoms. Irradiation caused immediate cell death, mainly limited to the colorectum. At 6 wk postirradiation, several crypts displayed signs of radiation-induced degeneration. The degenerating crypts were seen alongside crypts that appeared perfectly healthy. Crypt survival was reduced after the fourth fraction regardless of dose, whereas the number of macrophages increased. Angiogenesis was induced, likely as a compensatory mechanism for hypoxia. Four months postirradiation, mice began to show radiation-induced symptoms, and histological examination revealed an extensive crypt loss and fibrosis. Our model is uniquely suitable for studying the long-term trajectory and underlying mechanisms of radiation-induced gastrointestinal injury. NEW & NOTEWORTHY A novel mouse model for studying the long-term trajectory of radiation-induced gut injury. The method allows for the use of high doses and multiple fractions, with minor impact on animal health for at least 3 mo. Crypt loss and a slow progression of fibrosis is observed. Crypt degeneration is a process restricted to isolated crypts. Crypt degeneration is presented as a convenient proxy endpoint for long-term radiation-induced gut injury.
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| 8. |
- Bull, Cecilia, 1977
(författare)
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Brain Regeneration - in vitro and in vivo studies of exercise-related effects on brain plasticity
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Neural stem and progenitor cells in the germinal regions of the adult brain, such as the hippocampus, are of great interest, because they provide the possibility for enhanced brain plasticity or can contribute to endogenous cell replacement after injury or disease. Voluntary exercise was recently shown to robustly induce cellular and structural plasticity, thereby contributing to overall brain health. This thesis focuses on exercise-related effects on cell genesis of neurons and oligodendrocytes in vitro and in vivo. In Paper I, we demonstrated that the exercise-induced, endogenously released opioid peptide ?-endorphin enhanced oligodendrogenesis in adult hippocampal progenitors in vitro. Results revealed a requirement for the helix-loop? helix transcriptional regulator ?Inhibitor of Differentiation? (Id) 1 in opioid-induced oligodendrogenesis. In Paper II, we studied the effects of voluntary exercise during adulthood on neurogenesis and behavior, subsequent to irradiation in the young mouse brain. Voluntary exercise following irradiation restored the hippocampal stem cell pool, increased neurogenesis, and ameliorated irradiation-induced alterations in behavior. Moreover, orientation of immature neurons in the hippocampal dentate gyrus was perturbed after irradiation; however, voluntary exercise restored proper orientation. In Paper III, we proceeded to investigate potential effects of voluntary exercise on oligodendrogenesis after irradiation to the immature brain. We demonstrate an efficient irradiation-induced reduction in the total number of Olig2-positive cells of the corpus callosum, considered to be mainly oligodendroglial cells, without affecting the number of newborn glial progenitor cells. Our results also reveal that, in contrast to the beneficial effects of exercise on neurogenesis in the hippocampus, voluntary running does not seem to affect cell proliferation or oligodendrogenesis in the corpus callosum. In conclusion, this thesis demonstrates the usefulness of physical exercise for functional and structural brain recovery, with special emphasis on insults to the juvenile brain. In addition, these results highlight the capacity of the adult brain to regenerate through activation of endogenous neural progenitors and stem cells.
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| 9. |
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| 10. |
- Bull, Cecilia, 1977, et al.
(författare)
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Intra-abdominal Surgery and Intestinal Syndromes After Pelvic Radiation Therapy
- 2024
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Ingår i: ADVANCES IN RADIATION ONCOLOGY. - 2452-1094. ; 9:1
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To determine the effects of intra-abdominal surgery on the intensities of 5 radiation -induced intestinal syndromes in survivors of pelvic cancer. Methods and Materials: The analysis included 623 women born in 1927 or later who had survived cancer. They all had received external radiation therapy toward the pelvic area to treat gynecologic cancers. Information from 344 women who did not undergo irradiation, matched for age and residency, was also included. Main outcome measures after the surgical procedures were the intensity scores for 5 radiation -induced intestinal syndromes: urgency-tenesmus syndrome, fecal -leakage syndrome, excessive mucus discharge, excessive gas discharge, and blood discharge. The scores were based on symptom frequencies obtained from patient -reported outcomes and on factor loadings obtained from a previously reported factor analysis. Follow-up was 2 to 15 years after radiation therapy. Results: Among survivors of cancer, intra-abdominal surgery increased the intensity of the urgency-tenesmus syndrome, the fecalleakage syndrome, excessive gas discharge, and blood discharge but had a negligible effect on mucus discharge. Intra-abdominal surgery had an especially negative effect on the urgency-tenesmus syndrome. Although the combination of appendectomy with 1 or more other intra-abdominal surgeries resulted in the highest score for all syndromes, appendectomy alone had weak to no effect. In women who did not undergo irradiation, a similar pattern was seen, albeit with much lower scores. Conclusions: We found intra-abdominal surgery to be a risk factor among survivors of gynecologic cancer, increasing the intensity score of 4 out of 5 radiation -induced intestinal syndromes. During radiation therapy, it may be worthwhile to pay extra attention to the dose of unwanted ionizing radiation to the intestines if the patient previously has undergone intra-abdominal surgery.
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