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Introduction Radiation is known to be an inducer of cancer, however, radiation is also often used in a useful manner in radiotherapy and diagnostic imaging. In this research, we investigated the efficiency of different radiation qualities to induce DNA damage and how this damage is repaired by different cell types. Material and methods Lymphocytes, MCF-10A cells and epithelial cells in resected breast tissue were irradiated with high LET fast neutrons and low LET 30 kV X-rays and 1.2 MeV 60 Co γ -rays. By means of the γ H2AX-foci assay we analyzed the efficiency in DNA DSB-induction by the different radiation qualities. With the micronucleus (MN) assay we analyzed how efficient these DSB, induced by different radiation qualities, were repaired by the cell. Results While a lower number of radiation-induced γ H2AX-foci was observed for neutron radiation compared to γ -rays until about 4h post-IR, foci repair was slower and more residual foci were present at later time points. Furthermore, neutrons seem to be more effective in inducing MN. Irradiation of human lymphocytes with 30kV X-rays resulted in a modest increase in the number of γ H2AX-foci compared to γ -rays, but these DSB were more difficult to repair correctly by the cell and resulted in a more pronounced increase in MN compared to γ -rays. Furthermore, in the 0–20 mGy dose-range a low-dose hypersensitive response for DSB induction was observed in mammary epithelial cells present in resected breast tissue, probably caused by the bystander effect. Conclusion These results are important to assess the effects of radiotherapy and may have important implications for the risk assessment of mammography screening. [ABSTRACT FROM AUTHOR]

Introduction 67 Ga radiopharmaceuticals have been associated with the diagnosis of lymphomas and inflammation. This isotope has a half-life of approximately three days and can be utilized for quick and effective basic biological testing. Our interest is therefore the design and synthesis of various gallium complexes which would be evaluated in solid and solution state via nuclear magnetic resonance (NMR), infrared spectroscopy (IR) and X-ray diffraction (XRD). The chemical behaviour in solution state is compared to the absolute configuration of the gallium complexes to improve the understanding of any factors which may influence the biological properties of the metallo-organic complexes. An important aspect in pharmaceutical design is the synthesis of complexes to accommodate aspects such as the ease of synthesis; purity; environmental influences; as well as the synthesis conducted by medical personnel and not synthetic chemists. Material and methods Typical synthetic procedures of chemical entities (pharmaceuticals, ligands, complexes, assemblies, etc.) are classically performed by means of various solution based methods (solvothermal). An (almost) solvent-free method of synthesis (neat, liquid-, seeding-, ion-assisted grinding) has been recognized as potentially faster, environmentally friendly and economically acceptable ways to prepare new and known compounds. We have therefore also re-evaluated the synthetic methods of the carboxamide and Schiff base ligands which could potentially be coordinated to gallium(III). Due to their high charge density, Ga(III) prefer hard donors, such as amine-N and carboxylate-O atoms. Furthermore the nuclear biological potential of the ligands and 67 Ga coordinated ligand complexes would be evaluated to determine whether they could potentially be used for PET and SPECT imaging as diagnostic agents. Results Three novel Schiff base ligands (S1, S2 and S3) were prepared by economical and environmentally friendly methods described above and used for the radiolabelling with 67 Ga. These ligands were characterized by NMR, IR and XRD. All three radiolabelled ligands utilized by CHO-K1 cells and showed an increase in cellular uptake when compared to the 67 Ga chloride control ( 67 GaCl 3 ). Compared to 67 GaCl 3 , no significant growth delay was observed in the cells regardless of the ligand used for the radiolabeling experiment. An increased amount of radioactivity per cell is required to fully report the conditions needed for effective growth inhibition of cells and the possibility of it being suitable as a potential diagnostic and/or therapeutic pharmaceutical. Conclusion We hereby report the synthesised complexes, their solid and solution state character including the crystal structures of several ligand systems used. In addition to the nuclear biological behaviour compared to gallium(III) chloride control. [ABSTRACT FROM AUTHOR]

Introduction Radiological health concerns for individuals exposed to ionizing radiation are governed by both the extent of exposure, as well as the microscopic dose distribution of the radiation modality. Several quantitative biological endpoints have been developed for radiation dose estimation and are employed worldwide. For real world biodosimetry applications, qualitative aspects such as the radiation type and homogeneity of exposure are vital in the decision making process with respect to suitable medical interventions. Materials and methods Whole blood samples collected from two consenting adults were exposed to 60 Co γ -rays to doses ranging from 1–6 Gy and 0–2 Gy p(66)/Be neutrons. The samples exposed to 60 Co γ -rays were subsequently diluted with un-irradiated blood to yield a series of equivalent total body doses (ETBD) from 0 up to 4 Gy. Dicentric formation frequencies in T-lymphocyte metaphase spreads were enumerated with the aid of a semi-automated image analysis microscopy system. Results Dicentric formation induction frequencies were used to estimate whole body doses for each sample respectively. Estimated whole body doses where compared to the equivalent total body dose (ETBD) and found to be in agreement (Pearson’s ρ 0.97 < p < 0.99). Furthermore the distribution of cytogenetic effects amongst cells within each sample was used to calculate dispersion indices. Similarly to heterogeneous exposures, where damage events appear to be grouped in a specific subpopulation of cells, samples exposed to high-LET radiation also align to this trend. The intercellular distribution of dicentric aberrations for heterogeneously exposed samples ( σ 2 / y ¯ ≥ 1.2 ) and high LET neutron samples ( σ 2 / y ¯ ≈ 1.2 ) were found to be over-dispersed assuming a Poisson distribution applies to the induction of dicentric formations in cells. Conclusion The dispersion parameter proves to be a useful addition to the dicentric chromosome assay to ascertain qualitative aspects of the exposure conditions required for effective population triage for samples analysed with the high throughput automated image analysis system. [ABSTRACT FROM AUTHOR]