Nuclear medical expertise delivered by telemedicine in a 'dirty bomb' exercise

Management of victims in a 'dirty bomb' incident requires communication between the physicians directly involved and experts in radiation medicine. Telemedicine is an excellent tool to support doctors – who may not have specific training in radiation medicine – in handling radiation casualties. We have successfully used telemedicine in an exercise of the Federal Police in Germany. Experts in radiation medicine were provided by the Bundeswehr Institute of Radiobiology. Simple PC-based videoconferencing equipment was used with a 128 kbit/s ISDN line. To facilitate a standardized approach, a new questionnaire for radiation accidents was developed and tested during the exercise. A special camera was used for capturing skin images. Advice for patient treatment and strategies for safeguarding personnel and the environment during the exercise was provided almost immediately.

Comparing the Hematopoetic Syndrome Time Course in the NHP Animal Model to Radiation Accident Cases From the Database Search

Since controlled clinical studies on drug administration for the acute radiation syndrome are lacking, clinical data of human radiation accident victims as well as experimental animal models are the main sources of information. This leads to the question of how to compare and link clinical observations collected after human radiation accidents with experimental observations in non-human primate (NHP) models. Using the example of granulocyte counts in the peripheral blood following radiation exposure, approaches for adaptation between NHP and patient databases on data comparison and transformation are introduced. As a substitute for studying the effects of administration of granulocyte-colony stimulating factor (G-CSF) in human clinical trials, the method of mathematical modeling is suggested using the example of G-CSF administration to NHP after total body irradiation.

Alteration of miRNA expression in early endothelial cells after exposure with sub-lethal sulfur mustard concentrations

BACKGROUND/AIM

Sulfur mustard (SM) is known to induce chronic wound healing disorders as well as disturbed endothelial regeneration. It is known that wound healing as well as endothelial regeneration are controlled by micro-RNA (miRNA). As nothing is known today about the effect of SM onto miRNA expression we wanted to investigate whether there is an effect of sub-lethal concentrations of SM onto the miRNA expression of endothelial cells.

METHODS

Early endothelial cells (EEC) were incubated with different sub-lethal concentrations of sulfur mustard (SM) in-vitro. Cells were subsequently analyzed with respect to survival and colony-forming capacity. In addition, the nuclear structure was investigated with respect to apoptosis, micronuclei or abnormal forming using the MAA assay. Six hundred sixty-seven different miRNA species from both, treated and untreated EEC were quantified.

RESULTS

The sub-lethal concentrations IC1, IC5 or IC10 were used. While performing the MAA assay the cells showed a time dependent change in nucleus structure from normal to abnormal, without significant changes in apoptosis being observed. In the colony-forming assay a weak cell proliferation capacity was revealed. Under all conditions they lost their capacity to form colonies. Out of 667 investigated miRNAs in total 66 showed a significant change in expression upon incubation with SM. 19 miRNAs were up-regulated and 47 down-regulated. The strongest correlation between SM concentration and up-regulation was found for mmu-miR-92a-3p* (hsa-miR-92a). Seven miRNAs showed a change in expression similar to endothelial cells from younger or older mice.

CONCLUSION

The presented work demonstrates that sulfur mustard (SM) has an effect on miRNA expression in general. The observed changes in expression in early endothelial cells correlates to the known effects of SM. Further studies have to investigate if these findings are in direct dependence and if these relationships can be used to alleviate the sulfur mustard induced clinical damage.

Expression of blood serum proteins and lymphocyte differentiation clusters after chronic occupational exposure to ionizing radiation

This study aimed to assess effects of chronic occupational exposure on immune status in Mayak workers chronically exposed to ionizing radiation (IR). The study cohort consists of 77 workers occupationally exposed to external gamma-rays at total dose from 0.5 to 3.0 Gy (14 individuals) and workers with combined exposure (external gamma-rays at total dose range 0.7-5.1 Gy and internal alpha-radiation from incorporated plutonium with a body burden of 0.3-16.4 kBq). The control group consists of 43 age- and sex-matched individuals who never were exposed to IR, never involved in any cleanup operations following radiation accidents and never resided at contaminated areas. Enzyme-linked immunoassay and flow cytometry were used to determine the relative concentration of lymphocytes and proteins. The concentrations of T-lymphocytes, interleukin-8 and immunoglobulins G were decreased in external gamma-exposed workers relative to control. Relative concentrations of NKT-lymphocytes, concentrations of transforming growth factor-β, interferon gamma, immunoglobulins A, immunoglobulins M and matrix proteinase-9 were higher in this group as compared with control. Relative concentrations of T-lymphocytes and concentration of interleukin-8 were decreased, while both the relative and absolute concentration of natural killers, concentration of immunoglobulins A and M and matrix proteinase-9 were increased in workers with combined exposure as compared to control. An inverse linear relation was revealed between absolute concentration of T-lymphocytes, relative and absolute concentration of T-helpers cells, concentration of interferon gamma and total absorbed dose from external gamma-rays in exposed workers. For workers with incorporated plutonium, there was an inverse linear relation of absolute concentration of T-helpers as well as direct linear relation of relative concentration of NKT-lymphocytes to total absorbed red bone marrow dose from internal alpha-radiation. In all, chronic occupational IR exposure of workers induced a depletion of immune cells in peripheral blood of the individuals involved.

Dose-dependent uptake of 3'-deoxy-3'-[(18) F]fluorothymidine by the bowel after total-body irradiation

PURPOSE

The aim of this study is to non-invasively assess early, irradiation-induced normal tissue alterations via metabolic imaging with 3'-deoxy-3'-[(18) F]fluorothymidine ([(18) F]FLT).

PROCEDURES

Twenty-nine male C57BL/6 mice were investigated by [(18) F]FLT positron emission tomography for 7 days after total body irradiation (1, 4, and 8 Gy) versus 'sham' irradiation (0 Gy). Target/background ratios were determined. The imaging results were validated by histology and immunohistochemistry (Thymidine kinase 1, Ki-67).

RESULTS

[(18) F]FLT demonstrated a dose-dependent intestinal accumulation post irradiation. Mean target/background ratio (±standard error) 0 Gy: 1.4 (0.2), 1 Gy: 1.7 (0.1), 4 Gy: 3.1 (0.3), 8 Gy: 4.2 (0.6). Receiver operating characteristic analysis (area under the curve, p value): 0 vs. 1 Gy: 0.81, 0.049; 0 vs. 4 Gy: 1.0, 0.0016; and 0 vs. 8 Gy: 1.0, 0.0020. Immunohistochemistry confirmed the results.

CONCLUSIONS

[(18) F]FLT seems to provide dose-dependent information on radiation-induced proliferation in the bowel. This opens the perspective for monitoring therapy-related side-effects as well as assessing, e.g., radiation accident victims.

Expression and Y435-phosphorylation of Abelson interactor 1 (Abi1) promotes tumour cell adhesion, extracellular matrix degradation and invasion by colorectal carcinoma cells

Background

The Abelson tyrosine kinase (c-Abl) inhibitor STI571 (Glivec®) has been shown to effectively inhibit colorectal cancer cell migration and invasion. The c-Abl substrate abelson interactor 1 (Abi1) is a key regulator of actin reorganization and upregulated in colorectal carcinoma. The specific role of Abi1 in relation to extracellular matrix degradation and effects of targeting Abi1 phosphorylation have not yet been examined. Here, we investigated the role of Abi1 in relation to invasive properties in colorectal cancer.

Methods and results

In 56 primary human colorectal carcinoma samples, we found overexpression of Abi1 in 39% at the invasive edge of the tumour, associated with an infiltrative phenotype and high-grade tumour cell budding (p = 0.001). To explore the role of Abi1 in vitro, we employed the Abi1 expressing and KRAS-mutated CHD1 model and performed matrix degradation assays that showed Abi1 localization at specific sites of matrix degradation. Moreover, quantification of matrix dissolution demonstrated suppression after RNAi knockdown of Abi1 by 95% (p = 0.001). Importantly, treatment with STI571 did abolish Abi1 Y435-phosphorylation, suppressed the matrix dissolution, decreased fibronectin attachment, and suppressed cell invasion through reconstituted extracellular matrix.

Conclusion

Our data indicate that phosphorylated Abi1 contributes to the invasive properties of colorectal cancer.

Gene expression analysis in Mayak workers with prolonged occupational radiation exposure

The authors evaluated gene expression in the peripheral blood in relation to occupational exposure in Mayak workers to find out about the existence of a permanent post exposure signature. Workers were exposed to combined incorporated ²³⁹Pu and external gamma rays (n = 82) or to external gamma rays only (n = 18), and 50 unexposed individuals served as controls. Peripheral blood was taken from workers older than 70 y. RNA was isolated, converted into cDNA, and stored at -20°C. A two-stage study design was performed focusing on examinations on the transcriptional (mRNA) and post-transcriptional level (microRNA). In the first stage, 40 samples were identified for screening purposes and selection of candidate genes. For examinations on the transcriptional level, whole genome microarrays and qRT-PCR were employed on the post-transcriptional level (667 microRNAs). Candidate genes were assessed by (1) introducing a twofold difference in gene expression over the reference group and (2) showing a significant p-value using the Kruskal-Wallis test. From 42,545 transcripts of the whole genome microarray, 376 candidate genes (80 up-regulated and 296 down-regulated relative to the reference group) were selected. Expression of almost all of these genes (70-98%) appeared significantly associated with internal ²³⁹Pu and to a lesser extent were associated with external gamma-ray exposure (2-30%). Associations in the same direction were found for 45 microRNAs. Although both exposures led to modulations of different gene sets in different directions, the authors could detect no differences in gene set enrichment analysis.

Radiation exposure case management after incorporation of radionuclides

The release of radioactive material due to accidents or terroristic actions can result in radioactive contamination of the environment and may lead to intake and incorporation of radionuclides with the consequence of prolonged radiation exposure. In this case, a decision about countermeasures must be carried out as soon as possible to reduce the resulting radiation dose. In order to be prepared for such a scenario, an Assessment and Documentation System has been developed to support the rapid assessment of internal exposures and to assist in decision making. Radionuclide distributions, excretion rates, and resulting exposures have been calculated on the basis of a reference scenario. The documentation of the results in the form of tables and graphs allows the easy and quick interpretation of measurements in terms of exposure and intake. The system in its present status gives information about possibilities of countermeasures; it is the intention of the next steps of development to give advice on the basis of estimated avertable doses.

Significance of bioindicators to predict survival in irradiated minipigs

The minipig is emerging as a potential alternative non-rodent animal model. Several biological markers (e.g., blood counts, laboratory parameters, and clinical signs) have been proposed for rapid triage of radiation victims. Here, the authors focus on the significance of bio-indicators for prediction of survivors after irradiation and compare it with human data; the relationship between these biomarkers and radiation dose is not part of this study. Male Göttingen minipigs (age 4-5 mo, weight 9-10 kg) were irradiated (or sham-irradiated) bilaterally with gamma-photons (⁶⁰Co, 0.5-0.6 Gy min⁻¹) in the dose range of 1.6-12 Gy. Peripheral blood cell counts, laboratory parameters, and clinical symptoms were collected up to 10 d after irradiation and analyzed using logistic regression analysis and calculating ROC curves. In moribund pigs, parameters such as decreased lymphocyte/granulocyte counts, increased C-reactive protein, alkaline phosphatase values, as well as increased citrulline values and body temperature, significantly (p < 0.002 up to p < 0.0001) discriminated non-survivors from survivors with high precision (ROC > 0.8). However, most predictive within the first 3 d after exposure was a combination of decreased lymphocyte counts and increased body temperature observed as early as 3 h after radiation exposure (ROC: 0.93-0.96, p < 0.0001). Sham-irradiated animals (corresponding to "worried wells") could be easily discriminated from dying pigs, thus pointing to the diagnostic significance of this analysis. These data corroborate with earlier findings performed on human radiation victims suffering from severe hematological syndrome and provide further evidence for the suitability of the minipig model as a potential alternative non-rodent animal model.

Comparison of the needs for biodosimetry for large-scale radiation events for military versus civilian populations

The aim of this paper is to compare and contrast the needs for biodosimetry for initial triage for military forces and civilian populations when there are radiation exposures that involve potentially a large number of persons. Several differences in the likely scenarios for exposure of military forces include a greater likelihood of having higher rates of significant exposures, inhomogeneous exposures, significant doses from neutrons, and combined injury. Measurements will be able to begin sooner than for exposures in civilian settings because medical facilities usually are an integral part of the way military forces are deployed. It also will be very feasible to have personnel that will be trained and equipped specifically for rapid deployment to assess dose. As a consequence, the most appropriate biodosimetry techniques will include features that are not present or are less important for civilian settings; i.e., the need for changes that become measureable very soon after the radiation is received, the ability to complete measurements in very close proximity to the subjects (so samples do not need to be transported out and results returned), increased capability of resolving homogeneity of the exposure, ability to be carried out in an injured person, capability of determining whether neutrons have made a significant contribution to dose, and the ability to rely on more sophisticated equipment and trained personnel to carry out the measurements at the point of care.

Threshold limits for biological indication of prolonged radiation exposure using mFISH

Chromosome aberration (translocation) yield was investigated by mFISH in peripheral blood lymphocytes of Mayak Production Association (PA) workers with prolonged occupational exposure to ionizing radiation (IR). A dose threshold for cytogenetic indication of a prolonged occupational radiation exposure was estimated for Mayak PA workers using functions of dose distributions. Two limits were estimated for the indication of IR exposure to workers with a prolonged external gamma-ray exposure: These are a background translocation yield of N₀ = 0.812 ± 0.149% and a dose threshold of indication D₀ estimated to be approximately 1 Gy.

Transient gene therapy to treat cutaneous radiation syndrome: development in a minipig model

Cutaneous radiation syndrome is the delayed consequence of localized skin exposure to high doses of ionizing radiation. Adipocyte derived stem cells injection may improve tissue regeneration through secreted factors. Thus mesenchymal stem cells secretome optimization, using transient transfection, may represent a new strategy to treat this syndrome. Sonic hedgehog, a secreted protein involved in cell proliferation and angiogenesis, has been chosen as a first candidate. Here preliminary results are reported of the therapeutic potential of transient gene therapy to cure cutaneous radiation syndrome in a minipig model. Adipocyte derived stem cells were transiently transfected by electroporation with a plasmid coding for Sonic Hedgehog. Göttingen minipigs were locally irradiated using a (60)Co gamma source at the dose of 50 Gy and received Phosphate Buffer Salin (controls: n = 8), stem cells (50 × 10⁶ each time, n = 5) or transfected stem cells (25±7 × 10⁶ each time, n = 1). All controls exhibited a homogeneous clinical evolution of cutaneous radiation syndrome with final necrosis (day 91). In stem cell injected minipigs, an ultimate wound healing was observed in four out of five grafted animals (day 130 ± 28, complete in two of them) (historical results). The Sonic hedgehog animal, albeit injected with a lower number of transfected stem cells, presented a very similar evolution of skin healing without necrosis or uncontrolble pain. Globally this preliminary report suggests that local injection of Sonic Hedgehog transfected adipocyte derived stem cells may improve wound healing. Thus work is ongoing to evaluate this therapeutic strategy on a larger number of animals.

Discriminating metastasised from non-metastasised seminoma based on transcriptional changes in primary tumours using NGS

Background:

We aimed to better discriminate (occult) metastasised from non-metastasised seminoma based on transcriptional changes of small RNAs in the primary tumour.

Methods:

Total RNAs including small RNAs were isolated from five testicular tumours of each, lymphogenic, occult and non-metastasised patients. Next-generation sequencing (SOLID, Life Technologies) was used to examine transcriptional changes. Small RNAs showing ⩾50 reads and a significant ⩾2-fold difference using non-metastasised tumours as the reference group were examined in univariate logistic regression analysis and combinations of two small RNAs were further examined using support vector machines.

Results:

On average, 1.3 × 10⁷, 1.4 × 10⁷ and 1.7 × 10⁷ small RNA reads were detectable in non-metastasised, occult and lymphogenic metastasised seminoma, respectively, of which 30–32% remained after trimming. Between 59 and 68% represented annotated reads and between 8.6 and 11% were annotated small RNA tags. Of them, 137 small RNAs showed>50 reads and a two-fold difference to the reference. In univariate analysis, 32–38 small RNAs significantly discriminated lymphogenic/occult from non-metastasised seminoma, and among these different comparisons, it were the same small RNAs in 51–88%. Many combinations of two of these small RNAs allowed a complete discrimination of metastasised from non-metastasised seminoma irrespective of the metastasis subtype.

Conclusions:

Metastasised and non-metastasised seminoma can be completely discriminated with a combination of two small RNAs.

Clinically apparent and occult metastasized seminoma: almost indistinguishable on the transcriptional level

Purpose

The aim of the present study was to examine the biological differences between seminomas with occult and clinically apparent metastases at the time of diagnosis of the primary tumor to gain insight into the biology of these tumors and facilitate the identification of novel predictors of seminoma metastasis.

Materials and Methods

Total RNA including small RNAs was isolated from testicular tumors of patients with pure seminoma presenting with lymphogenic metastasis (n = 5, clinical stage IIb/c) and occult metastasis (n = 5, clinical stage I). The regulation of biological processes was examined (1) throughout the mRNA transcriptome (whole genome microarrays, 8×60 K Array, Agilent with 4 samples/group) and (2) the miRNA transcriptome employing small RNA next generation sequencing (SOLID, Life Technologies with 5 samples/group). Protein coding genes (mRNAs) and small RNAs showing a significant (≥2-fold) difference between the groups were identified. Finally (3), we examined 95 candidate miRNAs in 36 apparent metastasized and another 5 occult metastasized seminoma using logistic regression analysis.

Results

Among 19,596 genes, on average 12,894 mRNAs appeared expressed (65.8%, SD+/−2.4; range, 62.0–69.3%) and 16.99×10⁶/13.94×10⁶ small RNA reads were identified for apparent/occult metastasized seminoma. These reads on average convert into 9,901/9,675 small RNAs including 422/404 mature microRNAs. None of these mRNAs/small RNAs met our selection criteria for candidate genes. From 95 candidate miRNAs 44 appeared expressed, with 3 of them showing weak but significant (p = 0.05) differences among both groups.

Conclusions

Occult and apparent metastasized seminomas are biologically almost indistinguishable and probably represent no separate tumor entities. These findings may simplify future research on seminoma metastasis.

Small RNAs in the peripheral blood discriminate metastasized from non-metastasized seminoma

BACKGROUND

We aimed to better discriminate metastasized (lymphogen/occult/both combined) from non-metastasized seminoma based on post-transcriptional changes examined in the peripheral blood.

METHODS

Total RNAs including small RNAs were isolated from the peripheral blood of patients suffering from metastasized testicular tumours (lymphogen, n = 5, clinical stage IIb/c; occult, n = 5, clinical stage I) and non-metastasized patients (n = 5, clinical stage I). Small RNA next generation sequencing (SOLID, Life Technologies) was employed to examine post-transcriptional changes. We searched for small RNAs showing at least 50 reads and a significant  ≥ 2-fold difference using peripheral blood small RNAs of non-metastasized tumours as the reference group. Candidate small RNAs were examined in univariate logistic regression analysis and combinations of two small RNAs were further examined using support vector machines.

RESULTS

On average 1.3 x 10(7), 1.2 x 10(7) and 1.2 x 10(7) small RNA reads were detectable in non-metastasized, lymphogen and occult metastasized seminoma, respectively of which 73-76% remained after trimming. From these between 80-82% represented annotated reads and 7.2-7.8% (1.6-1.7 x 10(4)) were annotated small RNA tags. Of them 137 small RNAs showed > 50 reads and a ≥ two-fold difference to the reference. In univariate analysis we detected 33-35 different small RNAs which significantly discriminated lymphogen/occult/combined metastasized from non-metastasized seminoma and among these different comparisons it were the same small RNAs in 44-79%. Many combinations of two of these small RNAs completely discriminated metastasized from non-metastasized seminoma irrespective of the metastasis subtype.

CONCLUSIONS

Metastasized (either lymphogen or occult) seminoma can be completely discriminated from non-metastasized seminoma with a combination of two small RNAs measured in the peripheral blood.

DNA damage focus analysis in blood samples of minipigs reveals acute partial body irradiation

Radiation accidents frequently involve acute high dose partial body irradiation leading to victims with radiation sickness and cutaneous radiation syndrome that implements radiation-induced cell death. Cells that are not lethally hit seek to repair ionizing radiation (IR) induced damage, albeit at the expense of an increased risk of mutation and tumor formation due to misrepair of IR-induced DNA double strand breaks (DSBs). The response to DNA damage includes phosphorylation of histone H2AX in the vicinity of DSBs, creating foci in the nucleus whose enumeration can serve as a radiation biodosimeter. Here, we investigated γH2AX and DNA repair foci in peripheral blood lymphocytes of Göttingen minipigs that experienced acute partial body irradiation (PBI) with 49 Gy (±6%) Co-60 γ-rays of the upper lumbar region. Blood samples taken 4, 24 and 168 hours post PBI were subjected to γ-H2AX, 53BP1 and MRE11 focus enumeration. Peripheral blood lymphocytes (PBL) of 49 Gy partial body irradiated minipigs were found to display 1–8 DNA damage foci/cell. These PBL values significantly deceed the high foci numbers observed in keratinocyte nuclei of the directly γ-irradiated minipig skin regions, indicating a limited resident time of PBL in the exposed tissue volume. Nonetheless, PBL samples obtained 4 h post IR in average contained 2.2% of cells displaying a pan-γH2AX signal, suggesting that these received a higher IR dose. Moreover, dispersion analysis indicated partial body irradiation for all 13 minipigs at 4 h post IR. While dose reconstruction using γH2AX DNA repair foci in lymphocytes after in vivo PBI represents a challenge, the DNA damage focus assay may serve as a rapid, first line indicator of radiation exposure. The occurrence of PBLs with pan-γH2AX staining and of cells with relatively high foci numbers that skew a Poisson distribution may be taken as indicator of acute high dose partial body irradiation, particularly when samples are available early after IR exposure.

Linking the human response to unplanned radiation and treatment to the nonhuman primate response to controlled radiation and treatment

A key difficulty in developing countermeasures against radiation-induced health impairments is the clear lack of controlled clinical studies, due to the relatively low number of radiation victims worldwide. Instead, established and accepted animal models, as well as the recommendations of national and international expert panels and committees, are the main sources of information. Therefore, the development of countermeasures requires comparison of data from many sources and accumulation of information consistent with the U. S. Food and Drug Administration's "Animal Rule." A new approach is the comparative analysis of human data from the SEARCH (System for Evaluation and Archiving of Radiation Accidents based on Case Histories) database and data from nonhuman primate (NHP) animal model studies. The SEARCH database contains 824 clinical cases from 81 radiation accidents in 19 countries. This exceptional collection of clinical data from accidentally radiation-exposed persons is analyzed regarding clinical signs and symptoms of radiation-induced health impairments. To analyze the time course of radiation syndromes, clinical parameters common to the SEARCH and NHP databases have to be assigned into comparable categories of clinical severity for each species. The goal is to establish a method for comparison of human and NHP data, validate the NHP data as a surrogate for human efficacy/clinical studies, and open a way for the extraction of diagnostic and treatment methods for humans after radiation exposure according to relevant regulations.

[Cutaneous damage after acute exposure to ionizing radiation: decisive for the prognosis of radiation accident victims]

The cutaneous radiation syndrome includes all deterministic effects on the skin and visible parts of the mucosa from ionizing radiation. The Intensity and duration of radiation-induced skin symptoms depend on the kind and quality of ionizing radiation. The aim of this study was the investigation of the importance of the time of the development of radiation induced-skin effects on the prognosis of radiation accident victims. Clinical data about radiation accident victims from the database SEARCH were used. 211 cases with good documentation regarding radiation-induced skin effects were selected. From these 211 patients, 166 survived the acute phase of the acute radiation syndrome, while 45 died during the acute phase. Among those patients who did not survive the acute phase, 82.2 % showed their first documented radiation-induced skin symptoms during the first 3 days after radiation exposure. Of those patients whose first documented radiation-induced skin symptoms appeared on or after day four, 94.2 % survived the acute phase. The time to the occurrence of the first radiation-induced skin effects is diagnostically significant. The skin plays an important role in the clinical course of radiation syndromes and in the development of radiation-induced multi-organ failure. In a retrospective data analysis like this, the quality of data might be a limitation.

Cellular internalization of fibroblast growth factor-12 exerts radioprotective effects on intestinal radiation damage independently of FGFR signaling

PURPOSE

Several fibroblast growth factors (FGFs) were shown to inhibit radiation-induced tissue damage through FGF receptor (FGFR) signaling; however, this signaling was also found to be involved in the pathogenesis of several malignant tumors. In contrast, FGF12 cannot activate any FGFRs. Instead, FGF12 can be internalized readily into cells using 2 cell-penetrating peptide domains (CPP-M, CPP-C). Therefore, this study focused on clarifying the role of FGF12 internalization in protection against radiation-induced intestinal injury.

METHODS AND MATERIALS

Each FGF or peptide was administered intraperitoneally to BALB/c mice in the absence of heparin 24 hours before or after total body irradiation with γ rays at 9 to 12 Gy. Several radioprotective effects were examined in the jejunum.

RESULTS

Administration of FGF12 after radiation exposure was as effective as pretreatment in significantly promoting intestinal regeneration, proliferation of crypt cells, and epithelial differentiation. Two domains, comprising amino acid residues 80 to 109 and 140 to 169 of FGF12B, were identified as being responsible for the radioprotective activity, so that deletion of both domains from FGF12B resulted in a reduction in activity. Interestingly, these regions included the CPP-M and CPP-C domains, respectively; however, CPP-C by itself did not show an antiapoptotic effect. In addition, FGF1, prototypic FGF, possesses a domain corresponding to CPP-M, whereas it lacks CPP-C, so the fusion of FGF1 with CPP-C (FGF1/CPP-C) enhanced cellular internalization and increased radioprotective activity. However, FGF1/CPP-C reduced in vitro mitogenic activity through FGFRs compared with FGF1, implying that FGFR signaling might not be essential for promoting the radioprotective effect of FGF1/CPP-C. In addition, internalized FGF12 suppressed the activation of p38α after irradiation, resulting in reduced radiation-induced apoptosis.

CONCLUSIONS

These findings indicate that FGF12 can protect the intestine against radiation-induced injury through its internalization, independently of FGFRs, suggesting that cellular uptake of FGF12 is an alternative signaling pathway useful for cancer radiation therapy.

Iodine-131 dose-dependent gene expression: alterations in both normal and tumour thyroid tissues of post-Chernobyl thyroid cancers

BACKGROUND

A strong, consistent association between childhood irradiation and subsequent thyroid cancer provides an excellent model for studying radiation carcinogenesis.

METHODS

We evaluated gene expression in 63 paired RNA specimens from frozen normal and tumour thyroid tissues with individual iodine-131 (I-131) doses (0.008-8.6 Gy, no unirradiated controls) received from Chernobyl fallout during childhood (Ukrainian-American cohort). Approximately half of these randomly selected samples (32 tumour/normal tissue RNA specimens) were hybridised on 64 whole-genome microarrays (Agilent, 4 × 44 K). Associations between I-131 dose and gene expression were assessed separately in normal and tumour tissues using Kruskal-Wallis and linear trend tests. Of 155 genes significantly associated with I-131 after Bonferroni correction and with ≥2-fold increase per dose category, we selected 95 genes. On the remaining 31 RNA samples these genes were used for validation purposes using qRT-PCR.

RESULTS

Expression of eight genes (ABCC3, C1orf9, C6orf62, FGFR1OP2, HEY2, NDOR1, STAT3, and UCP3) in normal tissue and six genes (ANKRD46, CD47, HNRNPH1, NDOR1, SCEL, and SERPINA1) in tumour tissue was significantly associated with I-131. PANTHER/DAVID pathway analyses demonstrated significant over-representation of genes coding for nucleic acid binding in normal and tumour tissues, and for p53, EGF, and FGF signalling pathways in tumour tissue.

CONCLUSION

The multistep process of radiation carcinogenesis begins in histologically normal thyroid tissue and may involve dose-dependent gene expression changes.

Laboratory intercomparison of gene expression assays

The possibility of a large-scale acute radiation exposure necessitates the development of new methods that could provide rapid individual dose estimates with high sample throughput. The focus of the study was an intercomparison of laboratories' dose-assessment performances using gene expression assays. Lithium-heparinized whole blood from one healthy donor was irradiated (240 kVp, 1 Gy/min) immediately after venipuncture at approximately 37°C using single X-ray doses. Blood samples to establish calibration curves (0.25-4 Gy) as well as 10 blinded test samples (0.1-6.4 Gy) were incubated for 24 h at 37°C supplemented with an equal volume of medium and 10% fetal calf serum. For quantitative reverse transcription polymerase chain reaction (qRT-PCR), samples were lysed, stored at -20°C and shipped on ice. For the Chemical Ligation Dependent Probe Amplification methodology (CLPA), aliquots were incubated in 2 ml CLPA reaction buffer (DxTerity), mixed and shipped at room temperature. Assays were run in each laboratory according to locally established protocols. The mean absolute difference (MAD) of estimated doses relative to the true doses (in Gy) was calculated. We also merged doses into binary categories reflecting aspects of clinical/diagnostic relevance and examined accuracy, sensitivity and specificity. The earliest reported time on dose estimates was <8 h. The standard deviation of technical replicate measurements in 75% of all measurements was below 11%. MAD values of 0.3-0.5 Gy and 0.8-1.3 Gy divided the laboratories contributions into two groups. These fourfold differences in accuracy could be primarily explained by unexpected variances of the housekeeping gene (P = 0.0008) and performance differences in processing of calibration and blinded test samples by half of the contributing laboratories. Reported gene expression dose estimates aggregated into binary categories in general showed an accuracies and sensitivities of 93-100% and 76-100% for the groups, with low MAD and high MAD, respectively. In conclusion, gene expression-based dose estimates were reported quickly, and for laboratories with MAD between 0.3-0.5 Gy binary dose categories of clinical significance could be discriminated with an accuracy and sensitivity comparable to established cytogenetic assays.

Laboratory intercomparison on the γ-H2AX foci assay

The focus of the study is an intercomparison of laboratories' dose-assessment performances using the γ-H2AX foci assay as a diagnostic triage tool for rapid individual radiation dose assessment. Homogenously X-irradiated (240 kVp, 1 Gy/min) blood samples for establishing calibration data (0.25-4 Gy) as well as blinded test samples (0.1-6.4 Gy) were incubated at 37°C for 2 and 24 h (repair time) and sent to the participants. The foci assay was performed according to protocols individually established in participating laboratories and therefore varied. The time taken to report dose estimates was documented for each laboratory. Additional information concerning laboratory organization/characteristics as well as assay performance was collected. The mean absolute difference (MAD) of estimated doses relative to the actual doses was calculated and radiation doses were merged into four triage categories reflecting clinical relevance to calculate accuracy, sensitivity and specificity. First γ-H2AX based dose estimates were reported 7 h after sample receipt. Estimates were similarly accurate for 2 and 24 h repair times, providing scope for its use in the early phase of a radiation exposure incident. Equal accuracy was achieved by scoring 20, 30, 40 or 50 cells per sample. However, MAD values of 0.5-0.7 Gy and 1.3-1.7 Gy divided the data sets into two groups, driven mainly by the considerable differences in foci yields between calibration and blind samples. Foci yields also varied dramatically between laboratories, highlighting reproducibility issues as an important caveat of the foci assay. Nonetheless, foci counts could distinguish high- and low-dose samples in all data sets and binary dose categories of clinical significance could be discriminated with satisfactory accuracy (mean 84%, ±0.03 SEM). Overall, the results suggest that the γ-H2AX assay is a useful tool for rapidly screening individuals for significant exposures that occurred up to at least 24 h earlier, and may help to prioritize cytogenetic dosimetry follow-up.

Comparison of established and emerging biodosimetry assays

Rapid biodosimetry tools are required to assist with triage in the case of a large-scale radiation incident. Here, we aimed to determine the dose-assessment accuracy of the well-established dicentric chromosome assay (DCA) and cytokinesis-block micronucleus assay (CBMN) in comparison to the emerging γ-H2AX foci and gene expression assays for triage mode biodosimetry and radiation injury assessment. Coded blood samples exposed to 10 X-ray doses (240 kVp, 1 Gy/min) of up to 6.4 Gy were sent to participants for dose estimation. Report times were documented for each laboratory and assay. The mean absolute difference (MAD) of estimated doses relative to the true doses was calculated. We also merged doses into binary dose categories of clinical relevance and examined accuracy, sensitivity and specificity of the assays. Dose estimates were reported by the first laboratories within 0.3-0.4 days of receipt of samples for the γ-H2AX and gene expression assays compared to 2.4 and 4 days for the DCA and CBMN assays, respectively. Irrespective of the assay we found a 2.5-4-fold variation of interlaboratory accuracy per assay and lowest MAD values for the DCA assay (0.16 Gy) followed by CBMN (0.34 Gy), gene expression (0.34 Gy) and γ-H2AX (0.45 Gy) foci assay. Binary categories of dose estimates could be discriminated with equal efficiency for all assays, but at doses ≥1.5 Gy a 10% decrease in efficiency was observed for the foci assay, which was still comparable to the CBMN assay. In conclusion, the DCA has been confirmed as the gold standard biodosimetry method, but in situations where speed and throughput are more important than ultimate accuracy, the emerging rapid molecular assays have the potential to become useful triage tools.

Hemopoietic response to low dose-rates of ionizing radiation shows stem cell tolerance and adaptation

Chronic exposure of mammals to low dose-rates of ionizing radiation affects proliferating cell systems as a function of both dose-rate and the total dose accumulated. The lower the dose-rate the higher needs to be the total dose for a deterministic effect, i.e., tissue reaction to appear. Stem cells provide for proliferating, maturing and functional cells. Stem cells usually are particularly radiosensitive and damage to them may propagate to cause failure of functional cells. The paper revisits 1) medical histories with emphasis on the hemopoietic system of the victims of ten accidental chronic radiation exposures, 2) published hematological findings of long-term chronically gamma-irradiated rodents, and 3) such findings in dogs chronically exposed in large life-span studies. The data are consistent with the hypothesis that hemopoietic stem and early progenitor cells have the capacity to tolerate and adapt to being repetitively hit by energy deposition events. The data are compatible with the "injured stem cell hypothesis", stating that radiation-injured stem cells, depending on dose-rate, may continue to deliver clones of functional cells that maintain homeostasis of hemopoiesis throughout life. Further studies perhaps on separated hemopoietic stem cells may unravel the molecular-biology mechanisms causing radiation tolerance and adaptation.

Medical management of radiation accidents: capabilities and deployment principles of the Bundeswehr Institute of Radiobiology

Radiation accidents are fortunately infrequent occurrences, but since their consequences can be very serious as in the Chernobyl and the Fukushima nuclear accidents, medical management of radiation accidents is of great importance. Besides several other tasks, medical management of radiation accidents is one of the key tasks of the Bundeswehr Institute of Radiobiology. Within a Task Force Unit for medical chemical, biological, radiological, and nuclear (CBRN) Defense, the institute provides designated personnel who will perform clinical investigations on the scene and will liaise with the institute, where different methods for biological dosimetry and dose reconstruction will be performed. The most important aspects of efficient medical management of radiation accidents are diagnosis of radiation-induced health damage, determination of the cause, dealing with contamination/incorporation, pathophysiological and therapeutic principles, preparatory planning, national and international cooperation and training. Military and non-military institutions have to work closely together when it comes to radiation accidents and since national resources are limited and could be exhausted, international networks can help to ensure medical treatment for radiation accident victims.

Serotonin and ionizing radiation synergistically affect proliferation and adhesion molecule expression of malignant melanoma cells

BACKGROUND

Mast cells are key effectors of the immune system and are involved in a variety of physiological and pathophysiological processes. Dermal mast cells have been demonstrated to degranulate as a consequence of ionizing radiation exposure. Mast cells accumulate at the periphery of skin tumours including malignant melanoma. Melanoma cells thus represent a potential target for the action of mediators released from irradiated mast cells.

OBJECTIVE

In this study, we evaluated the effects of serotonin and ionizing radiation on the proliferation and the adhesion molecule expression of malignant melanoma cells.

METHODS

Human mast cells (HMC-1) were examined for serotonin release after irradiation using an enzyme-linked immunosorbent assay (ELISA). Protein expression of serotonin receptors and adhesion molecules on human melanoma cells (IPC-298) was investigated by flow cytometry. Cell attachment to fibronectin was determined by an adhesion assay. Proliferation and cell cycle kinetics were analysed by proliferation assay and 5-bromodeoxyuridine (BrdU)/DNA dual parameter flow cytometry, respectively.

RESULTS

Ionizing radiation exposure resulted in serotonin release by HMC-1 cells. Expression of serotonin receptors was detected on IPC-298 cells. Serotonin enhanced the radiation-induced reduction in melanoma cell proliferation. Serotonin and ionizing radiation synergistically increased the expression of adhesion molecules on melanoma cells and improved cell adhesion to fibronectin. The up-regulation of cellular adhesion molecule expression was attenuated by inhibitors to phosphatidylinositol 3-kinase, mitogen-activated protein (MAP) ERK kinase and protein kinase C.

CONCLUSIONS

Our data suggest that serotonin released from irradiated dermal mast cells modulates the radiation response of human melanoma cells. We postulate that radiation-induced mast cell degranulation and mediator release have a great impact on malignant melanoma cell development.

Application of adipocyte-derived stem cells in treatment of cutaneous radiation syndrome

Cutaneous radiation syndrome caused by local high dose irradiation is characterized by delayed outcome and incomplete healing. Recent therapeutic management of accidentally irradiated burn patients has suggested the benefit of local cellular therapy using mesenchymal stem cell grafting. According to the proposed strategy of early treatment, large amounts of stem cells would be necessary in the days following exposure and hospitalization, which would require allogeneic stem cells banking. In this context, the authors compared the benefit of local autologous and allogeneic adipocyte-derived stem cell injection in a large animal model. Minipigs were locally irradiated using a 60Co gamma source at a dose of 50 Gy and divided into three groups. Two groups were grafted with autologous (n = 5) or allogeneic (n = 5) adipocyte-derived stem cells four times after the radiation exposure, whereas the control group received the vehicle without cells (n = 8). A clinical score was elaborated to compare the efficiency of the three treatments. All controls exhibited local inflammatory injuries leading to a persistent painful necrosis, thus mimicking the clinical evolution in human victims. In the autologous adipocyte-derived stem cells group, skin healing without necrosis or uncontrollable pain was observed. In contrast, the clinical outcome was not significantly different in the adipocyte-derived stem cell allogeneic group when compared with controls. This study suggests that autologous adipocyte-derived stem cell grafting improves cutaneous radiation syndrome wound healing, whereas allogeneic adipocyte derived stem cells do not. Further studies will establish whether manipulation of allogeneic stem cells will improve their therapeutic potential.

Quality assurance in military medical research and medical radiation accident management

The provision of quality radiation-related medical diagnostic and therapeutic treatments cannot occur without the presence of robust quality assurance and standardization programs. Medical laboratory services are essential in patient treatment and must be able to meet the needs of all patients and the clinical personnel responsible for the medical care of these patients. Clinical personnel involved in patient care must embody the quality assurance process in daily work to ensure program sustainability. In conformance with the German Federal Government's concept for modern departmental research, the international standard ISO 9001, one of the relevant standards of the International Organization for Standardization (ISO), is applied in quality assurance in military medical research. By its holistic approach, this internationally accepted standard provides an excellent basis for establishing a modern quality management system in line with international standards. Furthermore, this standard can serve as a sound basis for the further development of an already established quality management system when additional standards shall apply, as for instance in reference laboratories or medical laboratories. Besides quality assurance, a military medical facility must manage additional risk events in the context of early recognition/detection of health risks of military personnel on deployment in order to be able to take appropriate preventive and protective measures; for instance, with medical radiation accident management. The international standard ISO 31000:2009 can serve as a guideline for establishing risk management. Clear organizational structures and defined work processes are required when individual laboratory units seek accreditation according to specific laboratory standards. Furthermore, international efforts to develop health laboratory standards must be reinforced that support sustainable quality assurance, as in the exchange and comparison of test results within the scope of external quality assurance, but also in the exchange of special diagnosis data among international research networks. In summary, the acknowledged standard for a quality management system to ensure quality assurance is the very generic standard ISO 9001.Health Phys. 103(2):221-225; 2012.

High potential for methodical improvements of FISH-based translocation analysis for retrospective radiation biodosimetry

Due to their high stability and accumulation over time, translocations are currently the cytogenetic marker of choice for radiation dose estimation following protracted radiation overexposures or overexposures that occurred up to several decades in the past (environmental/occupational/medical exposures). In the course of this, particular intention is focused on the quantification of low doses (≪ 1.0 Gy) for the purpose of evaluating potential associations between different radiation-induced chromosomal aberrations and future health impairments, usually cancer. However, existing limitations of FISH-based translocation analysis give occasion to further optimize this method. In particular, the practical and technical aspects of the method offer a great scope for potential improvements considerably facilitating the performance of extensive studies. On the one hand, huge studies encompassing a considerable number of different collectives aiming at the determination of spontaneous translocation frequencies due to several already determined and potentially not yet known confounders are essential for improved individual dosimetry in the very low dose range. An accurate and reliable individual dosimetry and the methodical feasibility of extensive FISH-based studies are prerequisites to further elucidate the characteristics of radiation induced cancer; e.g., radiation and radiation quality specificity or total dose and dose rate dependencies. This paper focuses on the practical and technical limitations of FISH-based translocation analysis, in fact the tremendous workload and costs of huge approaches, and points out how this could be overcome by method optimization, namely standardizing and automating translocation scoring to allow sharing of future work and planning of more extensive studies.

The Fukushima radiation accident: consequences for radiation accident medical management

The March 2011 radiation accident in Fukushima, Japan, is a textbook example of a radiation accident of global significance. In view of the global dimensions of the accident, it is important to consider the lessons learned. In this context, emphasis must be placed on consequences for planning appropriate medical management for radiation accidents including, for example, estimates of necessary human and material resources. The specific characteristics of the radiation accident in Fukushima are thematically divided into five groups: the exceptional environmental influences on the Fukushima radiation accident, particular circumstances of the accident, differences in risk perception, changed psychosocial factors in the age of the Internet and globalization, and the ignorance of the effects of ionizing radiation both among the general public and health care professionals. Conclusions like the need for reviewing international communication, interfacing, and interface definitions will be drawn from the Fukushima radiation accident.

Reliable and sample saving gene expression analysis approach for diagnostic tool development

This work answers the question of whether it is necessary to hybridize individual instead of pooled RNA samples on microarrays for screening gene targets suitable as diagnostic tools for radiation exposure scenarios, while at the same time meeting comparable microarray quality criteria. For developing new clinical diagnostic tools, a two-stage study design was employed in five projects. At first, pooled and not individual RNA samples were hybridized on microarrays for screening purposes. Potential gene candidates were selected based on their fold-change only. This was followed by a validation/quantification step using individual RNA samples and quantitative RT-PCR. Quality criteria from the screening approach with pooled RNA samples were compared with published data from the MicroArray Quality Control (MAQC) consortium that hybridized each reference RNA sample separately and established quality criteria for microarrays. When comparing both approaches, only insignificant differences for quality criteria such as false positives, sensitivity, specificity, and overall agreement were found. However, material, costs, and time were drastically reduced when hybridizing pooled RNA and gene targets applicable for clinical diagnostic purposes could be successfully selected. In search of new diagnostic tools for radiation exposure scenarios, the two stage study design using either pooled or individual RNA samples on microarrays shows comparable quality criteria, but the RNA pooling approach saves unique material, costs, and efforts and successfully selects gene targets that can be used for the desired diagnostic purposes.

Iodine-131 dose dependent gene expression in thyroid cancers and corresponding normal tissues following the Chernobyl accident

The strong and consistent relationship between irradiation at a young age and subsequent thyroid cancer provides an excellent model for studying radiation carcinogenesis in humans. We thus evaluated differential gene expression in thyroid tissue in relation to iodine-131 (I-131) doses received from the Chernobyl accident. Sixty three of 104 papillary thyroid cancers diagnosed between 1998 and 2008 in the Ukrainian-American cohort with individual I-131 thyroid dose estimates had paired RNA specimens from fresh frozen tumor (T) and normal (N) tissue provided by the Chernobyl Tissue Bank and satisfied quality control criteria. We first hybridized 32 randomly allocated RNA specimen pairs (T/N) on 64 whole genome microarrays (Agilent, 4×44 K). Associations of differential gene expression (log₂(T/N)) with dose were assessed using Kruskall-Wallis and trend tests in linear mixed regression models. While none of the genes withstood correction for the false discovery rate, we selected 75 genes with a priori evidence or P kruskall/P trend <0.0005 for validation by qRT-PCR on the remaining 31 RNA specimen pairs (T/N). The qRT-PCR data were analyzed using linear mixed regression models that included radiation dose as a categorical or ordinal variable. Eleven of 75 qRT-PCR assayed genes (ACVR2A, AJAP1, CA12, CDK12, FAM38A, GALNT7, LMO3, MTA1, SLC19A1, SLC43A3, ZNF493) were confirmed to have a statistically significant differential dose-expression relationship. Our study is among the first to provide direct human data on long term differential gene expression in relation to individual I-131 doses and to identify a set of genes potentially important in radiation carcinogenesis.

Gene expression comparisons performed for biodosimetry purposes on in vitro peripheral blood cellular subsets and irradiated individuals

We examined the benefit of gene expression analysis on peripheral blood cellular subsets of different radiosensitivity to elucidate their utility as biodosimeters for estimation of dose in irradiated individuals. Peripheral mononucleated cells were isolated from 18 healthy volunteers employing density separation in a CPT-NH tube. Peripheral mononucleated cells were cultured in RPMI 1640 medium containing 10% autologous serum and were irradiated with 0.1-1 Gy (240 kV, 13 mA, X rays at 1 Gy/min). A low-dose study was performed with isolated peripheral mononucleated cells from one healthy donor in three independent experiments. Peripheral mononucleated cells were irradiated at 0 (sham), 1, 2.5 and 5 cGy (70 kV, 13 mA X rays at 1 cGy/min) and gene expression was measured 24 and 48 h after irradiation. After irradiation, CD4(+) or CD8(+) cells were isolated by magnetic beads in independent experiments. RNA from lymphocyte subsets and peripheral mononucleated cells was isolated after 24 and 48 h and converted into cDNA. Gene expression of GADD45, CDKN1A, DDB2, PCNA, BAX and ATF3 were determined using RTQ-PCR. Data were analyzed employing linear and logistic regression analysis. The same examinations were performed in 5 individuals either diagnosed using CT scans (up to 4.3 cGy) or by administering (F-18)-fluoro-2-deoxy-d-glucose (F-18 FDG, 0.6 cGy). Methodological, intra- and inter-individual variability in 90-95% of measurements did not exceed the introduced twofold change over sham-irradiated control values in peripheral mononucleated cells and CD4(+) cells, and therefore no false positive results were observed. Dose reconstruction in peripheral mononucleated cells in opposite to CD4(+) lymphocytes required fewer genes and appeared more efficient (R-square = 84.8% compared to 51.8%). In vitro samples exposed to 10 cGy could be completely discriminated from sham-irradiated samples without individual pre-exposure controls, which coincided with our preliminary in vivo results. However, in vitro differential gene expression was measured relative to control values and did not differ significantly at 24 and 48 h after irradiation in contrast to our preliminary in vivo data. In addition, below 5 cGy in vitro data did not show reproducible significant changes in gene expression, which was opposite to our preliminary in vivo data. Therefore a twofold change in gene expression over control sufficiently controls for different sources of variance, and measuring gene expression in peripheral mononucleated cell for biological dosimetry purposes appears superior over measurements in lymphocyte subsets. The increased gene expression measured after low absorbed doses in vivo and in vitro might indicate a particular applicability of this method for a low-level radiation scenario in the absence of individual pre-exposure controls. However, the constant gene expression values measured up to 48 h in our in vitro model at doses >10 cGy, and the absence of reproducible and statistically significant gene expression changes below 5 cGy contrast to the preliminary in vivo results performed at similar doses. Therefore, measurements with our in vitro models should be interpreted cautiously.

Persistent DNA damage after high dose in vivo gamma exposure of minipig skin

Background

Exposure to high doses of ionizing radiation (IR) can lead to localized radiation injury of the skin and exposed cells suffer dsDNA breaks that may elicit cell death or stochastic changes. Little is known about the DNA damage response after high-dose exposure of the skin. Here, we investigate the cellular and DNA damage response in acutely irradiated minipig skin.

Methods and Findings

IR-induced DNA damage, repair and cellular survival were studied in 15 cm² of minipig skin exposed in vivo to ∼50 Co-60 γ rays. Skin biopsies of control and 4 h up to 96 days post exposure were investigated for radiation-induced foci (RIF) formation using γ-H2AX, 53BP1, and active ATM-p immunofluorescence. High-dose IR induced massive γ-H2AX phosphorylation and high 53BP1 RIF numbers 4 h, 20 h after IR. As time progressed RIF numbers dropped to a low of <1% of keratinocytes at 28–70 days. The latter contained large RIFs that included ATM-p, indicating the accumulation of complex DNA damage. At 96 days most of the cells with RIFs had disappeared. The frequency of active-caspase-3-positive apoptotic cells was 17-fold increased 3 days after IR and remained >3-fold elevated at all subsequent time points. Replicating basal cells (Ki67+) were reduced 3 days post IR followed by increased proliferation and recovery of epidermal cellularity after 28 days.

Conclusions

Acute high dose irradiation of minipig epidermis impaired stem cell replication and induced elevated apoptosis from 3 days onward. DNA repair cleared the high numbers of DBSs in skin cells, while RIFs that persisted in <1% cells marked complex and potentially lethal DNA damage up to several weeks after exposure. An elevated frequency of keratinocytes with persistent RIFs may thus serve as indicator of previous acute radiation exposure, which may be useful in the follow up of nuclear or radiological accident scenarios.

Autologous adipocyte derived stem cells favour healing in a minipig model of cutaneous radiation syndrome

Cutaneous radiation syndrome (CRS) is the delayed consequence of localized skin exposure to high doses of ionizing radiation. Here we examined for the first time in a large animal model the therapeutic potential of autologous adipose tissue-derived stroma cells (ASCs). For experiments, Göttingen minipigs were locally gamma irradiated using a ⁶⁰Co source at the dose of 50 Gy and grafted (n = 5) or not (n = 8). ASCs were cultured in MEM-alpha with 10% fetal calf serum and basic fibroblast growth factor (2 ng.mL⁻¹) and post irradiation were intradermally injected on days 25, 46, 67 and finally between days 95 and 115 (50×10⁶ ASCs each time) into the exposed area. All controls exhibited a clinical evolution with final necrosis (day 91). In grafted pigs an ultimate wound healing was observed in four out of five grafted animals (day 130 +/− 28). Immunohistological analysis of cytokeratin expression showed a complete epidermis recovery. Grafted ASCs accumulated at the dermis/subcutis barrier in which they attracted numerous immune cells, and even an increased vasculature in one pig. Globally this study suggests that local injection of ASCs may represent a useful strategy to mitigate CRS.

Acute radiation syndrome caused by accidental radiation exposure - therapeutic principles

Fortunately radiation accidents are infrequent occurrences, but since they have the potential of large scale events like the nuclear accidents of Chernobyl and Fukushima, preparatory planning of the medical management of radiation accident victims is very important. Radiation accidents can result in different types of radiation exposure for which the diagnostic and therapeutic measures, as well as the outcomes, differ. The clinical course of acute radiation syndrome depends on the absorbed radiation dose and its distribution. Multi-organ-involvement and multi-organ-failure need be taken into account. The most vulnerable organ system to radiation exposure is the hematopoietic system. In addition to hematopoietic syndrome, radiation induced damage to the skin plays an important role in diagnostics and the treatment of radiation accident victims. The most important therapeutic principles with special reference to hematopoietic syndrome and cutaneous radiation syndrome are reviewed.

First global consensus for evidence-based management of the hematopoietic syndrome resulting from exposure to ionizing radiation

OBJECTIVE

Hematopoietic syndrome (HS) is a clinical diagnosis assigned to people who present with ≥ 1 new-onset cytopenias in the setting of acute radiation exposure. The World Health Organization convened a panel of experts to evaluate the evidence and develop recommendations for medical countermeasures for the management of HS in a hypothetical scenario involving the hospitalization of 100 to 200 individuals exposed to radiation. The objective of this consultancy was to develop recommendations for treatment of the HS based upon the quality of evidence.

METHODS

English-language articles were identified in MEDLINE and PubMed. Reference lists of retrieved articles were distributed to panel members before the meeting and updated during the meeting. Published case series and case reports of individuals with HS, published randomized controlled trials of relevant interventions used to treat nonirradiated individuals, reports of studies in irradiated animals, and prior recommendations of subject matter experts were selected. Studies were extracted using the Grading of Recommendations Assessment Development and Evaluation (GRADE) system. In cases in which data were limited or incomplete, a narrative review of the observations was made. No randomized controlled trials of medical countermeasures have been completed for individuals with radiation-associated HS. The use of GRADE analysis of countermeasures for injury to hematopoietic tissue was restricted by the lack of comparator groups in humans. Reliance on data generated in nonirradiated humans and experimental animals was necessary.

RESULTS

Based upon GRADE analysis and narrative review, a strong recommendation was made for the administration of granulocyte colony-stimulating factor or granulocyte macrophage colony-stimulating factor and a weak recommendation was made for the use of erythropoiesis-stimulating agents or hematopoietic stem cell transplantation.

CONCLUSIONS

Assessment of therapeutic interventions for HS in humans exposed to nontherapeutic radiation is difficult because of the limits of the evidence.

Literature review and global consensus on management of acute radiation syndrome affecting nonhematopoietic organ systems

OBJECTIVES

The World Health Organization convened a panel of experts to rank the evidence for medical countermeasures for management of acute radiation syndrome (ARS) in a hypothetical scenario involving the hospitalization of 100 to 200 victims. The goal of this panel was to achieve consensus on optimal management of ARS affecting nonhematopoietic organ systems based upon evidence in the published literature.

METHODS

English-language articles were identified in MEDLINE and PubMed. Reference lists of retrieved articles were distributed to conferees in advance of and updated during the meeting. Published case series and case reports of ARS, publications of randomized controlled trials of relevant interventions used to treat nonirradiated individuals, reports of studies in irradiated animals, and prior recommendations of subject matter experts were selected. Studies were extracted using the Grading of Recommendations Assessment Development and Evaluation system. In cases in which data were limited or incomplete, a narrative review of the observations was made.

RESULTS

No randomized controlled trials of medical countermeasures have been completed for individuals with ARS. Reports of countermeasures were often incompletely described, making it necessary to rely on data generated in nonirradiated humans and in experimental animals. A strong recommendation is made for the administration of a serotonin-receptor antagonist prophylactically when the suspected exposure is >2 Gy and topical steroids, antibiotics, and antihistamines for radiation burns, ulcers, or blisters; excision and grafting of radiation ulcers or necrosis with intractable pain; provision of supportive care to individuals with neurovascular syndrome; and administration of electrolyte replacement therapy and sedatives to individuals with significant burns, hypovolemia, and/or shock. A strong recommendation is made against the use of systemic steroids in the absence of a specific indication. A weak recommendation is made for the use of fluoroquinolones, bowel decontamination, loperamide, and enteral nutrition, and for selective oropharyngeal/digestive decontamination, blood glucose maintenance, and stress ulcer prophylaxis in critically ill patients.

CONCLUSIONS

High-quality studies of therapeutic interventions in humans exposed to nontherapeutic radiation are not available, and because of ethical concerns regarding the conduct of controlled studies in humans, such studies are unlikely to emerge in the near future.

Micro-RNA expression in cisplatin resistant germ cell tumor cell lines

Background

We compared microRNA expression patterns in three cisplatin resistant sublines derived from paternal cisplatin sensitive germ cell tumor cell lines in order to improve our understanding of the mechanisms of cisplatin resistance.

Methods

Three cisplatin resistant sublines (NTERA-2-R, NCCIT-R, 2102EP-R) showing 2.7-11.3-fold increase in drug resistance after intermittent exposure to increasing doses of cisplatin were compared to their parental counterparts, three well established relatively cisplatin sensitive germ cell tumor cell lines (NTERA-2, NCCIT, 2102EP). Cells were cultured and total RNA was isolated from all 6 cell lines in three independent experiments. RNA was converted into cDNA and quantitative RT-PCR was run using 384 well low density arrays covering almost all (738) known microRNA species of human origin.

Results

Altogether 72 of 738 (9.8%) microRNAs appeared differentially expressed between sensitive and resistant cell line pairs (NTERA-2R/NTERA-2 = 43, NCCIT-R/NCCIT = 53, 2102EP-R/2102EP = 15) of which 46.7-95.3% were up-regulated (NTERA-2R/NTERA-2 = 95.3%, NCCIT-R/NCCIT = 62.3%, 2102EP-R/2102EP = 46.7%). The number of genes showing differential expression in more than one of the cell line pairs was 34 between NTERA-2R/NTERA-2 (79%) and NCCIT-R/NCCIT (64%), and 3 and 4, respectively, between these two cell lines and 2102EP-R/2102EP (about 27%). Only the has-miR-10b involved in breast cancer invasion and metastasis and has-miR-512-3p appeared to be up-regulated (2-3-fold) in all three cell lines. The hsa-miR-371-373 cluster (counteracting cellular senescence and linked with differentiation potency), as well as hsa-miR-520c/-520h (inhibiting the tumor suppressor p21) were 3.9-16.3 fold up-regulated in two of the three cisplatin resistant cell lines. Several new micro-RNA species missing an annotation towards cisplatin resistance could be identified. These were hsa-miR-512-3p/-515/-517/-518/-525 (up to 8.1-fold up-regulated) and hsa-miR-99a/-100/-145 (up to 10-fold down-regulated).

Conclusion

Examining almost all known human micro-RNA species confirmed the miR-371-373 cluster as a promising target for explaining cisplatin resistance, potentially by counteracting wild-type P53 induced senescence or linking it with the potency to differentiate. Moreover, we describe for the first time an association of the up-regulation of micro-RNA species such as hsa-miR-512-3p/-515/-517/-518/-525 and down-regulation of hsa-miR-99a/-100/-145 with a cisplatin resistant phenotype in human germ cell tumors. Further functional analyses are warranted to gain insight into their role in drug resistance.