RENEB Inter-Laboratory comparison 2017: limits and pitfalls of ILCs.

Purpose: In case of a mass-casualty radiological event, there would be a need for networking to overcome surge limitations and to quickly obtain homogeneous results (reported aberration frequencies or estimated doses) among biodosimetry laboratories. These results must be consistent within such network. Inter-laboratory comparisons (ILCs) are widely accepted to achieve this homogeneity.

α-Particle-induced DNA damage tracks in peripheral blood mononuclear cells of [Ra]RaCl-treated prostate cancer patients.

Purpose: One therapy option for prostate cancer patients with bone metastases is the use of [Ra]RaCl. The α-emitter Ra creates DNA damage tracks along α-particle trajectories (α-tracks) in exposed cells that can be revealed by immunofluorescent staining of γ-H2AX+53BP1 DNA double-strand break markers. We investigated the time- and absorbed dose-dependency of the number of α-tracks in peripheral blood mononuclear cells (PBMCs) of patients undergoing their first therapy with [Ra]RaCl.

Genomic Adaption and Mutational Patterns in a HaCaT Subline Resistant to Alkylating Agents and Ionizing Radiation.

Sulfur mustard (SM) is a chemical warfare agent that can damage DNA via alkylation and oxidative stress. Because of its genotoxicity, SM is cancerogenic and the progenitor of many chemotherapeutics. Previously, we developed an SM-resistant cell line via chronic exposure of the popular keratinocyte cell line HaCaT to increasing doses of SM over a period of 40 months.

Genome-Wide DNA Alterations in X-Irradiated Human Gingiva Fibroblasts.

While ionizing radiation (IR) is a powerful tool in medical diagnostics, nuclear medicine, and radiology, it also is a serious threat to the integrity of genetic material. Mutagenic effects of IR to the human genome have long been the subject of research, yet still comparatively little is known about the genome-wide effects of IR exposure on the DNA-sequence level. In this study, we employed high throughput sequencing technologies to investigate IR-induced DNA alterations in human gingiva fibroblasts (HGF) that were acutely exposed to 0.

Overcoming challenges in human saliva gene expression measurements.

Saliva, as a non-invasive and easily accessible biofluid, has been shown to contain RNA biomarkers for prediction and diagnosis of several diseases. However, systematic analysis done by our group identified two problematic issues not coherently described before: (1) most of the isolated RNA originates from the oral microbiome and (2) the amount of isolated human RNA is comparatively low. The degree of bacterial contamination showed ratios up to 1:900,000, so that only about one out of 900,000 RNA copies was of human origin, but the RNA quality (average RIN 6.

Assessment of α-amanitin toxicity and effects of silibinin and penicillin in different in vitro models.

Silibinin (Sil) is used as hepatoprotective drug and is approved for therapeutic use in amanitin poisoning. In our study we compared Sil-bis-succinate (Sil), a water-soluble drug approved for i.v.

Extended in vitro culture of primary human mesenchymal stem cells downregulates Brca1-related genes and impairs DNA double-strand break recognition.

Mesenchymal stem cells (MSCs) are multilineage adult stem cells with considerable potential for cell-based regenerative therapies. In vitro expansion changes their epigenetic and cellular properties, with a poorly understood impact on DNA damage response (DDR) and genome stability. We report here results of a transcriptome-based pathway analysis of in vitro-expanded human bone marrow-derived mesenchymal stem cell (hBM-MSCs), supplemented with cellular assays focusing on DNA double-strand break (DSB) repair.

CT Irradiation-induced Changes of Gene Expression within Peripheral Blood Cells.

Computed tomography (CT) is a crucial element of medical imaging diagnostics. The widespread application of this technology has made CT one of the major contributors to medical radiation burden, despite the fact that doses per individual CT scan steadily decrease due to the advancement of technology. Epidemiological risk assessment of CT exposure is hampered by the fact that moderate adverse effects triggered by low doses of CT exposure are likely masked by statistical fluctuations.

DNA Damage in Blood Leukocytes of Prostate Cancer Patients Undergoing PET/CT Examinations with [Ga]Ga-PSMA I&T.

The aim was to investigate the induction and repair of radiation-induced DNA double-strand breaks (DSBs) as a function of the absorbed dose to the blood of patients undergoing PET/CT examinations with [Ga]Ga-PSMA. Blood samples were collected from 15 patients before and at four time points after [Ga]Ga-PSMA administration, both before and after the PET/CT scan. Absorbed doses to the blood were calculated.

Effect of sulfur mustard on melanogenesis in vitro.

The chemical warfare agent sulfur mustard (SM) affects all cells in the epidermis including melanocytes which are responsible for melanin synthesis. After exposure to SM, pigment abnormalities like hypo- and hyperpigmentation can occur. The underlying molecular pathomechanisms of SM exposure on human melanogenesis have not been elucidated so far.

DNA damage in blood leucocytes of prostate cancer patients during therapy with Lu-PSMA.

Purpose: The aim of this study was to investigate the time- and dose-dependency of DNA double-strand break (DSB) induction and repair in peripheral blood leucocytes of prostate cancer patients during therapy with Lu-PSMA.

Methods: Blood samples from 16 prostate cancer patients receiving their first Lu-PSMA therapy were taken before and at seven time-points (between 1 h and 96 h) after radionuclide administration. Absorbed doses to the blood were calculated using integrated time-activity curves of the blood and the whole-body.

A mouse model for intellectual disability caused by mutations in the X-linked 2'‑O‑methyltransferase Ftsj1 gene.

Mutations in the X chromosomal tRNA 2'‑O‑methyltransferase FTSJ1 cause intellectual disability (ID). Although the gene is ubiquitously expressed affected individuals present no consistent clinical features beyond ID. In order to study the pathological mechanism involved in the aetiology of FTSJ1 deficiency-related cognitive impairment, we generated and characterized an Ftsj1 deficient mouse line based on the gene trapped stem cell line RRD143.

Expression levels of hnRNP K and p21WAF1/CIP1 are associated with resistance to radiochemotherapy independent of p53 pathway activation in rectal adenocarcinoma.

Ionizing radiation (IR) is frequently applied in the treatment of rectal adenocarcinoma, however, there is marked variance in the response to radiochemotherapy between individual tumors. In our previous investigations, it was shown that the overexpression of heterogeneous nuclear ribonucleoprotein K (hnRNP K) confers radioresistance to malignant melanoma and colorectal carcinoma (CRC) in vitro, however, the underlying mechanism remains to be elucidated. As hnRNP K, a p53 binding partner and cofactor for the transcriptional activation of p53 target genes, is overexpressed in CRC, the present study investigated the possible radioprotective effect of the hnRNP K/p53‑induced upregulation of p21 (also known as WAF1/CIP1) in rectal adenocarcinoma.

Correlation of the absorbed dose to the blood and DNA damage in leukocytes after internal ex-vivo irradiation of blood samples with Ra-224.

Background: Irradiation with α-particles creates densely packed damage tracks along particle trajectories in exposed cells, including complex DNA damage and closely spaced double-strand breaks (DSBs) in hit nuclei. Here, we investigated the correlation of the absorbed dose to the blood and the number of α-induced DNA damage tracks elicited in human blood leukocytes after ex-vivo in-solution exposure with Ra-224. The aim was to compare the data to previously published data on Ra-223 and to investigate differences in DNA damage induction between the two radium isotopes.

Genome-Wide Analysis of Interchromosomal Interaction Probabilities Reveals Chained Translocations and Overrepresentation of Translocation Breakpoints in Genes in a Cutaneous T-Cell Lymphoma Cell Line.

In classical models of tumorigenesis, the accumulation of tumor promoting chromosomal aberrations is described as a gradual process. Next-generation sequencing-based methods have recently revealed complex patterns of chromosomal aberrations, which are beyond explanation by these classical models of karyotypic evolution of tumor genomes. Thus, the term chromothripsis has been introduced to describe a phenomenon, where temporarily and spatially confined genomic instability results in dramatic chromosomal rearrangements limited to segments of one or a few chromosomes.

Exome Sequencing Discloses Ionizing-radiation-induced DNA Variants in the Genome of Human Gingiva Fibroblasts.

Ionizing radiation can induce genomic lesions such as DNA double-strand breaks whose incomplete or faulty repair can result in mutations, which in turn can influence cellular functions and alter the fate of affected cells and organ systems. Ionizing-radiation-induced sequence alterations/mutations occur in a stochastic manner, which contributes to an increased cancer risk in irradiated individuals. Ionizing radiation exposure, and particularly acute doses at high dose rates (as often observed in radiation accidents), induce alterations in the genome that in part will reflect specific characteristics of the DNA damage response and the repair mechanisms involved.

Immunological Markers of Chronic Occupational Radiation Exposure.

This study aimed to identify immunological biomarkers for prolonged occupational radiation exposure and thus studied a random sample of the Mayak Production Association worker cohort (91 individuals). The control group included 43 local individuals never employed at the Mayak Production Association. To identify biomarkers, two groups of workers were formed: the first one included workers chronically exposed to external gamma rays at cumulative doses of 0.

NHEJ Contributes to the Fast Repair of Radiation-induced DNA Double-strand Breaks at Late Prophase I Telomeres.

Exposure of cells to ionizing radiation induces DNA double-strand breaks. To repair double-strand breaks correctly, cells must distinguish between the ends of chromosomes (telomeres) and DNA double-strand breaks within chromosomes. Double-strand breaks in telomeric DNA may lead to telomere shortening and mutagenesis.

Correlation of Radiation Dose Estimates by DIC with the METREPOL Hematological Classes of Disease Severity.

The degree of severity of hematologic acute radiation syndrome (HARS) may vary across the range of radiation doses, such that dose alone may be a less reliable predictor of clinical course. We sought to elucidate the relationship between absorbed dose and risk of clinically relevant HARS in humans. We used the database SEARCH (System for Evaluation and Archiving of Radiation Accidents based on Case Histories), which contains the histories of radiation accident victims.

Generation of a human induced pluripotent stem cell (iPSC) line from a 51-year-old female with attention-deficit/hyperactivity disorder (ADHD) carrying a duplication of SLC2A3.

Fibroblasts were isolated from a skin biopsy of a clinically diagnosed 51-year-old female attention-deficit/hyperactivity disorder (ADHD) patient carrying a duplication of SLC2A3, a gene encoding neuronal glucose transporter-3 (GLUT3). Patient fibroblasts were infected with Sendai virus, a single-stranded RNA virus, to generate transgene-free human induced pluripotent stem cells (iPSCs). SLC2A3-D2-iPSCs showed expression of pluripotency-associated markers, were able to differentiate into cells of the three germ layers in vitro and had a normal female karyotype.

Live Dynamics of 53BP1 Foci Following Simultaneous Induction of Clustered and Dispersed DNA Damage in U2OS Cells.

Cells react differently to clustered and dispersed DNA double strand breaks (DSB). Little is known about the initial reaction to simultaneous induction of DSBs with different complexities. Here, we used live cell microscopy to analyse the behaviour of 53BP1-GFP (green fluorescence protein) foci formation at DSBs induced in U2OS cells by alpha particles, X-rays or mixed beams over a 75 min period post irradiation.

DNA damage in leukocytes after internal ex-vivo irradiation of blood with the α-emitter Ra-223.

Irradiation with high linear energy transfer α-emitters, like the clinically used Ra-223 dichloride, severely damages cells and induces complex DNA damage including closely spaced double-strand breaks (DSBs). As the hematopoietic system is an organ-at-risk for the treatment, knowledge about Ra-223-induced DNA damage in blood leukocytes is highly desirable. Therefore, 36 blood samples from six healthy volunteers were exposed ex-vivo (in solution) to different concentrations of Ra-223.

Cost-effectiveness of methods in personalized medicine. Results of a decision-analytic model in patients with acute myeloid leukemia with normal karyotype.

Background: During the last years, molecular genetic data are increasingly used as prognostic and predictive factors in acute myeloid leukemia (AML). The molecular genetic profile permits a rapid risk categorization and beyond that a prediction of differential treatment efficacy of post-remission chemotherapy versus an allogeneic hematopoietic cell transplantation (HCT) in specific subgroups.

Methods: The aim of this study was to evaluate cost-effectiveness of two different strategies of risk categorization (conventional cytogenetic diagnostics (CCD) versus molecular genetic diagnostics (MGD)) in patients with AML, using a decision-analytic state-transition model.