Dataset Information

Assessment of simulated high-dose partial-body irradiation by PCC-R assay.

ABSTRACT: The estimation of the dose and the irradiated fraction of the body is important information in the primary medical response in case of a radiological accident. The PCC-R assay has been developed for high-dose estimations, but little attention has been given to its applicability for partial-body irradiations. In the present work we estimated the doses and the percentage of the irradiated fraction in simulated partial-body radiation exposures at high doses using the PCC-R assay. Peripheral whole blood of three healthy donors was exposed to doses from 0-20 Gy, with ??Co gamma radiation. To simulate partial body irradiations, irradiated and non-irradiated blood was mixed to obtain proportions of irradiated blood from 10-90%. Lymphocyte cultures were treated with Colcemid and Calyculin-A before harvest. Conventional and triage scores were performed for each dose, proportion of irradiated blood and donor. The Papworth's u test was used to evaluate the PCC-R distribution per cell. A dose-response relationship was fitted according to the maximum likelihood method using the frequencies of PCC-R obtained from 100% irradiated blood. The dose to the partially irradiated blood was estimated using the Contaminated Poisson method. A new D? value of 10.9 Gy was calculated and used to estimate the initial fraction of irradiated cells. The results presented here indicate that by PCC-R it is possible to distinguish between simulated partial- and whole-body irradiations by the u-test, and to accurately estimate the dose from 10-20 Gy, and the initial fraction of irradiated cells in the interval from 10-90%.

SUBMITTER: Romero I

PROVIDER: S-EPMC3766303 | biostudies-literature | 2013 Sep

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Assessment of simulated high-dose partial-body irradiation by PCC-R assay.

Romero Ivonne I García Omar O Lamadrid Ana I AI Gregoire Eric E González Jorge E JE Morales Wilfredo W Martin Cécile C Barquinero Joan-Francesc JF Voisin Philippe P

Journal of radiation research 20130417 5

The estimation of the dose and the irradiated fraction of the body is important information in the primary medical response in case of a radiological accident. The PCC-R assay has been developed for high-dose estimations, but little attention has been given to its applicability for partial-body irradiations. In the present work we estimated the doses and the percentage of the irradiated fraction in simulated partial-body radiation exposures at high doses using the PCC-R assay. Peripheral whole b ...[more]

PMID: 23596200

Similar Datasets

Project description:There is clinical interest in the modulation of regulatory T cells for cancer therapy. The safety of these therapies in combination with conventional anti-cancer therapies, including radiation therapy, can be studied in animal models. The effects of partial depletion of regulatory T (Treg) cells with an anti-CD25 antibody in conjunction with ionizing radiation on inflammation and tissue injury were analyzed in C57BL/6 mice. An anti-CD25 antibody (PC61) was administered 3 days prior to 13 Gy lower-half hemi-body irradiation (HBI). The blood, spleen, mesenteric lymph nodes (mLNs) and inguinal lymph nodes (iLNs) were harvested at various times thereafter. Alterations in the proportion of leukocyte subsets including CD4(+) T cells, CD8(+) T cells, Treg cells, B cells, NK cells, NK1.1(+) T cells, macrophages and granulocytes were analyzed by FACS. The lungs, liver, pancreas, stomach, jejunum, duodenum, ileum, colon and kidney were harvested and studied by H&E staining. Expression of inflammatory mediators in plasma and tissue were investigated by ELISA. HBI significantly decreased the leukocyte pool though the various leukocyte subsets had different sensitivities to HBI. The administration of PC61 significantly decreased the proportion of Treg cells in spleen, iLN, mLN and blood (reduction of approximately 60%). Irradiation significantly increased the proportion of Treg cells in the spleen, iLN and mLN. HBI induced a systemic inflammatory reaction as demonstrated by increased plasma levels of IL-6, KC/CXCL1 and circulating granulocytes in the blood. Neutrophils also infiltrated the small bowel. The same general patterns were observed whether or not Treg cells were partially depleted with PC61 prior to HBI. These data demonstrate that partial depletion of Treg cells in these mice does not influence HBI-induced inflammatory response and tissue injury, and that combining anti-CD25 therapy with radiation may be safe and well tolerated in a clinical setting.

Project description:High-dose ionizing irradiation can cause extensive injuries in susceptible tissues. A noninvasive imaging technique that detects a surrogate marker of apoptosis may help characterize the dynamics of radiation-induced tissue damage. The goal of this study was to prove the concept of imaging the temporal and spatial distribution of damage in susceptible tissues after high-dose radiation exposure, using (99m)Tc-duramycin as a phosphatidylethanolamine-binding radiopharmaceutical.Rats were subjected to 15 Gy of total-body irradiation with x-rays. Planar whole-body (99m)Tc-duramycin scanning (n = 4 per time point) was conducted at 24, 48, and 72 h using a clinical ?-camera. On the basis of findings from planar imaging, preclinical SPECT data were acquired on control rats and on irradiated rats at 6 and 24 h after irradiation (n = 4 per time point). Imaging data were validated by ?-counting and histology, using harvested tissues in parallel groups of animals (n = 4).Prominent focal uptake was detected in the thymus as early as 6 h after irradiation, followed by a gradual decline in (99m)Tc-duramycin binding accompanied by extensive thymic atrophy. Early (6-24 h) radioactivity uptake in the gastrointestinal region was detected. Significant signal was seen in major bones in a slightly delayed fashion, at 24 h, which persisted for at least 2 d. This finding was paralleled by an elevation in signal intensity in the kidneys, spleen, and liver. The imaging results were consistent with ex vivo ?-counting results and histology. Relatively high levels of apoptosis were detected from histology in the thymus, guts, and bones, with the thymus undergoing substantial atrophy.As a proof of principle, this study demonstrated a noninvasive imaging technique that allows characterization of the temporal and spatial dynamics of injuries in susceptible tissues during the acute phase after high-dose ionizing irradiation. Such an imaging capability will potentially be useful for global, whole-body, assessment of tissue damage after radiation exposure. These data, in turn, will contribute to our general knowledge of tissue susceptibility to ionizing irradiation, as well as the onset and progression of tissue injuries.

Project description:In the event of a radiological or nuclear attack, advanced clinical countermeasures are needed for screening and medical management of the exposed population. In such a scenario, minimally invasive biomarkers that can accurately quantify radiation exposure would be useful for triage management by first responders. In this murine study, we evaluated the efficacy of a novel combination of radiation responsive proteins, Flt3 ligand (FL), serum amyloid A (SAA), matrix metalloproteinase 9 (MMP9), fibrinogen beta (FGB) and pentraxin 3 (PTX3) to predict the received dose after whole- or partial-body irradiation. Ten-week-old female C57BL6 mice received a single whole-body or partial-body dose of 18 Gy from a Pantak X-ray source at a dose rate of 2.28 Gy/min. Plasma was collected by cardiac puncture at 24, 48, 72 h and 1 week postirradiation. Plasma protein levels were determined via commercially available ELISA assay. A multivariate discriminant analysis was utilized to generate best-fit dose prediction models for whole-body exposures using the selected biomarker panel and its potential application to partial-body exposures was examined. The combination of values from FL, SAA, MMP9, FGB and PTX3 between 24 h and 1 week postirradiation yielded novel dose-response relationships. For day 1 postirradiation, the best-fit model yielded a predictive accuracy of 81% utilizing FL alone. The use of additional proteins did not enhance the model accuracy whereas, at day 2 postirradiation, the addition of PTX3 and FGB to FL increased the accuracy to 100%. At day 3 the use of FL and PTX3 yielded a predictive accuracy of 93% and at day 7 use of FL and SAA had an accuracy of 90%. Dose prediction of partial-body exposures based on the TBI model had a higher predictive accuracy when the percentage of the body exposed to radiation increased. Our findings indicate that this novel combination of radiation responsive biomarker proteins are an efficient method for predicting radiation exposure and are more accurate when used in concert compared to using any single biomarker protein alone.

Project description:CD4+ T helper cells are capable of mediating long-term antitumoral immune responses. We developed a combined immunotherapy (COMBO) using tumor antigen-specific T helper 1 cells (Tag-Th1), dual PD-L1/LAG-3 immune checkpoint blockade, and a low-dose total body irradiation (TBI) of 2 Gy, that was highly efficient in controlling the tumor burden of non-immunogenic RIP1-Tag2 mice with late-stage endogenous pancreatic islet carcinomas. In this study, we aimed to explore the impact of 2 Gy TBI on the treatment efficacy and the underlying mechanisms to boost CD4+ T cell-based immunotherapies. Methods: Heavily progressed RIP1-Tag2 mice underwent COMBO treatment and their survival was compared to a cohort without 2 Gy TBI. Positron emission tomography/computed tomography (PET/CT) with radiolabeled anti-CD3 monoclonal antibodies and flow cytometry were applied to investigate 2 Gy TBI-induced alterations in the biodistribution of endogenous T cells of healthy C3H mice. Migration and homing properties of Cy5-labeled adoptive Tag-Th1 cells were monitored by optical imaging and flow cytometric analyses in C3H and tumor-bearing RIP1-Tag2 mice. Splenectomy or sham-surgery of late-stage RIP1-Tag2 mice was performed before onset of COMBO treatment to elucidate the impact of the spleen on the therapy response. Results: First, we determined a significant longer survival of RIP1-Tag2 mice and an increased CD4+ T cell tumor infiltrate when 2 Gy TBI was applied in addition to Tag-Th1 cell PD-L1/LAG-3 treatment. In non-tumor-bearing C3H mice, TBI induced a moderate host lymphodepletion and a tumor antigen-independent accumulation of Tag-Th1 cells in lymphoid and non-lymphoid organs. In RIP1-Tag2, we found increased numbers of effector memory-like Tag-Th1 and endogenous CD4+ T cells in the pancreatic tumor tissue after TBI, accompanied by a tumor-specific Th1-driven immune response. Furthermore, the spleen negatively regulated T cell effector function by upregulation PD-1/LAG-3/TIM-3 immune checkpoints, providing a further rationale for this combined treatment approach. Conclusion: Low-dose TBI represents a powerful tool to foster CD4+ T cell-based cancer immunotherapies by favoring Th1-driven antitumoral immunity. As TBI is a clinically approved and well-established technique it might be an ideal addition for adoptive cell therapy with CD4+ T cells in the clinical setting.

Dataset Information

Assessment of simulated high-dose partial-body irradiation by PCC-R assay.

Publications

Assessment of simulated high-dose partial-body irradiation by PCC-R assay.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets