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| 2. |
- Canter, B. S., et al.
(författare)
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Radium-223-Induced Bystander Effects Cause DNA Damage and Apoptosis in Disseminated Tumor Cells in Bone Marrow
- 2021
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Ingår i: Molecular Cancer Research. - 1541-7786. ; 19:10, s. 1739-1750
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Tidskriftsartikel (refereegranskat)abstract
- Radiation-induced bystander effects have been implicated in contributing to the growth delay of disseminated tumor cells (DTC) caused by (RaCl2)-Ra-223, an alpha particle-emitting radiopharmaceutical. To understand how 223RaCl(2) affects the growth, we have quantified biological changes caused by direct effects of radiation and bystander effects caused by the emitted radiations on DTC and osteocytes. Characterizing these effects contribute to understanding the efficacy of alpha particle-emitting radiopharmaceuticals and guide expansion of their use clinically. MDA-MB-231 or MCF-7 human breast cancer cells were inoculated intratibially into nude mice that were previously injected intravenously with 50 or 600 kBq/kg (RaCl2)-Ra-223. At 1-day and 3-days postinoculation, tibiae were harvested and examined for DNA damage (g-H2AX foci) and apoptosis in osteocytes and cancer cells located within and beyond the range (70 mm) of alpha particles emitted from the bone surface. Irradiated and bystander MDA-MB-231 and MCF-7 cells harbored DNA damage. Bystander MDA-MB-231 cells expressed DNA damage at both treatment levels while bystander MCF-7 cells required the higher administered activity. Osteocytes also had DNA damage regardless of inoculated cancer cell line. The extent of DNA damage was quantified by increases in low (1-2 foci), medium (3-5 foci), and high (5thorn foci) damage. MDA-MB-231 but not MCF-7 bystander cells showed increases in apoptosis in (RaCl2)-Ra-223-treated animals, as did irradiated osteocytes. In summary, radiation-induced bystander effects contribute to DTC cytotoxicity caused by (RaCl2)-Ra-223.
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| 3. |
- Hosseinzadeh, Griffin, et al.
(författare)
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Weak Mass Loss from the Red Supergiant Progenitor of the Type II SN 2021yja
- 2022
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 935:1
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Tidskriftsartikel (refereegranskat)abstract
- We present high-cadence optical, ultraviolet (UV), and near-infrared data of the nearby (D approximate to 23 Mpc) Type II supernova (SN) 2021yja. Many Type II SNe show signs of interaction with circumstellar material (CSM) during the first few days after explosion, implying that their red supergiant (RSG) progenitors experience episodic or eruptive mass loss. However, because it is difficult to discover SNe early, the diversity of CSM configurations in RSGs has not been fully mapped. SN 2021yja, first detected within approximate to 5.4 hours of explosion, shows some signatures of CSM interaction (high UV luminosity and radio and x-ray emission) but without the narrow emission lines or early light-curve peak that can accompany CSM. Here we analyze the densely sampled early light curve and spectral series of this nearby SN to infer the properties of its progenitor and CSM. We find that the most likely progenitor was an RSG with an extended envelope, encompassed by low-density CSM. We also present archival Hubble Space Telescope imaging of the host galaxy of SN 2021yja, which allows us to place a stringent upper limit of less than or similar to 9 M-circle dot; on the progenitor mass. However, this is in tension with some aspects of the SN evolution, which point to a more massive progenitor. Our analysis highlights the need to consider progenitor structure when making inferences about CSM properties, and that a comprehensive view of CSM tracers should be made to give a fuller view of the last years of RSG evolution.
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| 4. |
- Leung, C. N., et al.
(författare)
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Dose-Dependent Growth Delay of Breast Cancer Xenografts in the Bone Marrow of Mice Treated with Ra-223: The Role of Bystander Effects and Their Potential for Therapy
- 2020
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Ingår i: Journal of Nuclear Medicine. - : Society of Nuclear Medicine. - 0161-5505 .- 2159-662X. ; 61:1, s. 89-95
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Tidskriftsartikel (refereegranskat)abstract
- The role of radiation-induced bystander effects in radiation therapy remains unclear. With renewed interest in therapy with alpha-particle emitters, and their potential for sterilizing disseminated tumor cells (DTCs), it is critical to determine the contribution of bystander effects to the overall response so they can be leveraged for maximum clinical benefit. Methods: Female Foxn1(nu) athymic nude mice were administered 0, 50, or 600 kBq/kg (RaCl2)-Ra-223 to create bystander conditions. At 24 hours after administration, MDA-MB-231 or MCF-7 human breast cancer cells expressing luciferase were injected into the tibial marrow compartment. Tumor burden was tracked weekly via bioluminescence. Results: The MDA-MB-231 xenografts were observed to have a 10-day growth delay in the 600 kBq/kg treatment group only. In contrast, MCF-7 cells had 7-and 65-day growth delays in the 50 and 600 kBq/kg groups, respectively. Histologic imaging of the tibial marrow compartment, alpha-camera imaging, and Monte Carlo dosimetry modeling revealed DTCs both within and beyond the range of the alpha-particles emitted from Ra-223 in bone for both MCF-7 and MDA-MB-231 cells. Conclusion: Taken together, these results support the participation of Ra-22(3)-induced antiproliferative/cytotoxic bystander effects in delayed growth of DTC xenografts. They indicate that the delay depends on the injected activity and therefore is dose-dependent. They suggest using (RaCl2)-Ra-223 as an adjuvant treatment for select patients at early stages of breast cancer.
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| 5. |
- Leung, Howell, et al.
(författare)
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Risk assessment with gut microbiome and metabolite markers in NAFLD development
- 2022
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Ingår i: Science Translational Medicine. - : American Association for the Advancement of Science (AAAS). - 1946-6234 .- 1946-6242. ; 14:648, s. eabk0855-
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Tidskriftsartikel (refereegranskat)abstract
- A growing body of evidence suggests interplay between the gut microbiota and the pathogenesis of nonalcoholic fatty liver disease (NAFLD). However, the role of the gut microbiome in early detection of NAFLD is unclear. Prospective studies are necessary for identifying reliable, microbiome markers for early NAFLD. We evaluated 2487 individuals in a community-based cohort who were followed up 4.6 years after initial clinical examination and biospecimen sampling. Metagenomic and metabolomic characterizations using stool and serum samples taken at baseline were performed for 90 participants who progressed to NAFLD and 90 controls who remained NAFLD free at the follow-up visit. Cases and controls were matched for gender, age, body mass index (BMI) at baseline and follow-up, and 4-year BMI change. Machine learning models integrating baseline microbial signatures (14 features) correctly classified participants (auROCs of 0.72 to 0.80) based on their NAFLD status and liver fat accumulation at the 4-year follow up, outperforming other prognostic clinical models (auROCs of 0.58 to 0.60). We confirmed the biological relevance of the microbiome features by testing their diagnostic ability in four external NAFLD case-control cohorts examined by biopsy or magnetic resonance spectroscopy, from Asia, Europe, and the United States. Our findings raise the possibility of using gut microbiota for early clinical warning of NAFLD development.
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| 6. |
- Rajon, D. A., et al.
(författare)
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Modeling bystander effects that cause growth delay of breast cancer xenografts in bone marrow of mice treated with radium-223
- 2021
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Ingår i: International Journal of Radiation Biology. - : Informa UK Limited. - 0955-3002 .- 1362-3095. ; 97:9, s. 1217-1228
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Tidskriftsartikel (refereegranskat)abstract
- Rationale The role of radiation-induced bystander effects in cancer therapy with alpha-particle emitting radiopharmaceuticals remains unclear. With renewed interest in using alpha-particle emitters to sterilize disseminated tumor cells, micrometastases, and tumors, a better understanding of the direct effects of alpha particles and the contribution of the bystander responses they induce is needed to refine dosimetric models that help predict clinical benefit. Accordingly, this work models and quantifies the relative importance of direct effects (DE) and bystander effects (BE) in the growth delay of human breast cancer xenografts observed previously in the tibiae of mice treated with (RaCl2)-Ra-223. Methods A computational model of MDA-MB-231 and MCF-7 human breast cancer xenografts in the tibial bone marrow of mice administered (RaCl2)-Ra-223 was created. A Monte Carlo radiation transport simulation was performed to assess individual cell absorbed doses. The responses of the breast cancer cells to direct alpha particle irradiation and gamma irradiation were needed as input data for the model and were determined experimentally using a colony-forming assay and compared to the responses of preosteoblast MC3T3-E1 and osteocyte-like MLO-Y4 bone cells. Using these data, a scheme was devised to simulate the dynamic proliferation of the tumors in vivo, including DE and BE propagated from the irradiated cells. The parameters of the scheme were estimated semi-empirically to fit experimental tumor growth. Results A robust BE component, in addition to a much smaller DE component, was required to simulate the in vivo tumor proliferation. We also found that the relative biological effectiveness (RBE) for cell killing by alpha particle radiation was greater for the bone cells than the tumor cells. Conclusion This modeling study demonstrates that DE of radiation alone cannot explain experimental observations of (RaCl2)-Ra-223-induced growth delay of human breast cancer xenografts. Furthermore, while the mechanisms underlying BE remain unclear, the addition of a BE component to the model is necessary to provide an accurate prediction of the growth delay. More complex models are needed to further comprehend the extent and complexity of (RaCl2)-Ra-223-induced BE.
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| 7. |
- Aad, G., et al.
(författare)
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- 2011
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Tidskriftsartikel (refereegranskat)
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| 8. |
- Aad, G., et al.
(författare)
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- 2012
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swepub:Mat__t (refereegranskat)
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| 9. |
- Aad, G., et al.
(författare)
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- 2012
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swepub:Mat__t (refereegranskat)
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| 10. |
- Aad, G., et al.
(författare)
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- 2012
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swepub:Mat__t (refereegranskat)
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