1,721,006 research outputs found
γ-H2AX detection in somatic and germ cells of mice
No full textThe phosphorylation of histone H2AX at serine 139 (γ-H2AX) is one of the first steps of DNA damage response and its detection is widely used as a sensitive marker for DNA double-strand breaks induced by ionizing radiation or other genotoxic agents. Immuno-stained phosphorylated histone can be measured in single cells by flow cytometry or single γ-H2AX foci can be visualized and counted microscopically in histological or cytological preparations. Animal studies are well recognized as important tools to study mechanisms of in vivo response to genotoxic stress. Tissues are composed by many cell types differing for function, differentiation, and proliferative capacity. In particular, due to the complexity of spermatogenesis and the heterogeneity of testicular cell subpopulations, an accurate characterization of damage in this tissue is difficult and requires an approach which allows the identification of damage in the different cellular compartments. This chapter presents techniques for γ-H2AX detection in mouse bone marrow and testicular cells. Furthermore, advantages and weaknesses of flow cytometric and microscopic methods are described. © Springer Science+Business Media, New York 2013
Rad54/Rad54B deficiency is associated to increased chromosome breakage in mouse spermatocytes
No full textRad54 protein is a key player of the homologous recombination pathway, required for deposition and stabilisation of Rad51 foci at double strand breaks. Its role at the meiotic prophase, when double strand breaks are physiologically introduced to allow recombination, is well described. However, the hypothesis that Rad54 deficiency affect chromosome integrity of germ cells in unirradiated and irradiated animals has not been tested yet. In this study, the occurrence of spontaneous and X-ray-induced chromosome aberrations was assessed by analysis of spermatocyte MI spreads or by application of micronucleus assay in early spermatids isolated from wild type and Rad54/Rad54B knockout (KO) mice. In Rad54/Rad54B KO mice, the spontaneous chromosome aberration frequency detected at MI was >10-fold higher than in wild type animals. In addition, after exposure to 1 Gy X-rays at the radiosensitive stage of diplotene, an enhanced response to radiation was observed in Rad54-deficient animals, corresponding to a 2-3 sensitivity factor in comparison to wild type mice. Also the spontaneous frequency of micronucleated round spermatids was on the average 10-fold higher in KO than in wild type mice, indicating that Rad54/Rad54B KO spermatocytes carrying chromosome aberrations are able to pass through the meiotic divisions and to continue the spermatogenesis process. Our results provide the first evidence of the role of Rad54/Rad54B in the maintenance of a stable karyotype during male meiosis, and suggest that Rad54/Rad54B deficiency may impact on the DNA integrity of developing mouse gametes. © 2018 The Author(s)
Study of TiO2 P25nanoparticles genotoxicity on lung, blood, and liver cells in lung overload andnon-overload conditionsafter repeated respiratory exposure in rats
No full textInhaled titanium dioxide (TiO2) nanoparticles (NPs) can have negative health effects, and have been shown to cause respiratory tract cancer in rats. Inflammation has been linked to oxidative stress, and both have been described as possible mechanisms for genotoxicity of NPs, but rarely examined side-by-side in animal studies. In the present study, a wide range of complementary endpoints have been performed to study TiO2 P25NP-induced genotoxicity in lung overload and non-overload conditions. Additionally, lung burden, inflammation, cytotoxicity and oxidative stress have also been evaluated in order to link genotoxicity with these responses. To assess quick and delayed responses after recovery, endpoints were evaluated at two time points: 2 h and 35 days after three repeated instillations. This study confirmed the previously described lung overload threshold at approximately 200-300cm2 of lung burden for total particle surface area lung deposition or 4.2 ml/kg for volume-based cumulative lung exposure dose, above which lung clearance is impaired and inflammation is induced. Our results went on to show that these overload doses induced delayed genotoxicity in lung, associated with persistent inflammation only at the highest dose. The lowest tested doses had no toxicity or genotoxicity effects in the lung. In blood, no lymphocyte DNA damage, erythrocytes chromosomal damage or gene mutation could be detected. Our data also demonstrated that only overload doses induced liver DNA lesions irrespective of the recovery time. Tested doses of TiO2 P25 NPs did not induce glutathione changes in lung, blood or liver at both recovery times. © The Author 2017
PyTrack: A Map-Matching-Based Python Toolbox for Vehicle Trajectory Reconstruction
No full textThe exponential growth of IoT devices, smartphones, smartwatches, and vehicles equipped with positioning technology, such as Global Positioning System (GPS) modules, has boosted the development of location-based services for several applications in Intelligent Transportation Systems. However, the inherent error of location-based technologies makes it necessary to align the positioning trajectories to the actual underlying road network, a process known as map-matching. To the best of our knowledge, there are no comprehensive tools that allow us to model street networks, conduct topological and spatial analyses of the underlying street graph, perform map-matching processes on GPS point trajectories, and deeply analyse and elaborate these reconstructed trajectories. To address this issue, we present PyTrack, an open-source map-matching-based Python toolbox designed for academics, researchers and practitioners that integrate the recorded GPS coordinates with data provided by the OpenStreetMap, an open-source geographic information system. This manuscript overviews the architecture of the library offering a detailed description of its capabilities and modules. Besides, we provide an introductory guide to getting started with PyTrack covering the most fundamental steps of our framework. For more information on PyTrack, users are encouraged to visit the official repository at https://github.com/cosbidev/PyTrack or the official documentation at https://pytrack-lib.readthedocs.io
Sperm DNA Integrity is Unaffected by Thiopurine Treatment in Men With Inflammatory Bowel Disease
No full textBackground and Aims: Sperm DNA integrity, concentration, and motility are suspected to be altered by thiopurines (azathioprine [AZA] and 6-mercaptopurine [6-MP]). We investigated the impact of thiopurines on semen quality in men with inflammatory bowel disease [IBD], by a comprehensive panel of semen analyses. Methods: Semen from 40 men with IBD, in remission on AZA/6-MP therapy, was prospectively collected and compared with samples from 40 healthy volunteers. Paired samples [off and on AZA/6-MP] were obtained from a subset of IBD patients, and blood and semen were collected to determine 6-MP transmission to the ejaculate. Sperm DNA fragmentation was evaluated via sperm chromatin structure assay [SCSA] and Comet analysis. Conventional World Health Organization [WHO] parameters, i.e. semen volume and sperm concentration, motility, and morphology, were assessed. Additionally, we measured thioguanine nucleotide [TGN] incorporation in sperm cell DNA. Results: Sperm DNA fragmentation levels did not differ between men with IBD on AZA/6-MP and healthy volunteers when evaluated by SCSA [p = 0.23] and Comet analysis [p = 0.72]. IBD patients on AZA/6-MP had significantly lower total and progressive sperm motility than healthy volunteers [48.5% versus 64.5%, p = 0.0003; 27.4% versus 43.3%, p = 0.0004; respectively], with no differences in concentration, volume, or morphology. The same trend was observed in the 10 paired samples. TGN incorporation was not detectable in sperm DNA, but 6-MP was detected in seminal plasma and correlated to blood levels [rs = 0.79, p = 0.02]. Conclusions: Thiopurines do not increase sperm DNA fragmentation but may impair sperm motility in this IBD cohort. Our findings support existing epidemiological data that thiopurine therapy is safe during preconception and should not be abandoned
Clinical and genomic safety of treatment with Ginkgo biloba L. leaf extract (IDN 5933/Ginkgoselect®Plus) in elderly: A randomised placebo-controlled clinical trial [GiBiEx]
No full textBackground: Numerous health benefits have been attributed to the Ginkgo biloba leaf extract (GBLE), one of the most extensively used phytopharmaceutical drugs worldwide. Recently, concerns of the safety of the extract have been raised after a report from US National Toxicology Program (NTP) claimed high doses of GBLE increased liver and thyroid cancer incidence in mice and rats. A safety study has been designed to assess, in a population of elderly residents in nursing homes, clinical and genomic risks associated to GBLE treatment. Methods: GiBiEx is a multicentre randomized clinical trial, placebo controlled, double blinded, which compared subjects randomized to twice-daily doses of either 120-mg of IDN 5933 (also known as Ginkgoselect®Plus) or to placebo for a 6-months period. IDN 5933 is extracted from dried leaves and contains 24.3% flavone glycosides and 6.1% of terpene lactones (2.9% bilobalide, 1.38% ginkgolide A, 0.66% ginkgolide B, 1.12% ginkgolide C) as determined by HPLC. The study was completed by 47 subjects, 20 in the placebo group and 27 in the treatment group. Clinical (adverse clinical effect and liver injury) and genomic (micronucleus frequency, comet assay, c-myc, p53, and ctnnb1 expression profile in lymphocytes) endpoints were assessed at the start and at the end of the study. Results: No adverse clinical effects or increase of liver injury markers were reported in the treatment group. The frequency of micronuclei [Mean Ratio (MR) = 1.01, 95% Confidence Intervals (95% CI) 0.86-1.18), and DNA breaks (comet assay) (MR = 0.91; 95% CI 0.58-1.43), did not differ in the two study groups. No significant difference was found in the expression profile of the three genes investigated. Conclusions: None of the markers investigated revealed a higher risk in the treatment group, supporting the safety of IDN 5933 at doses prescribed and for duration of six months. Trial registration: ClinicalTrials.gov Identifier: NCT03004508 , December 20, 2016. Trial retrospectively registered. © 2018 The Author(s)
Genotoxicity induced by foetal and infant exposure to magnetic fields and modulation of ionising radiation effects
No full textBackground: Few studies have investigated the toxicity and genotoxicity of extremely low frequency magnetic fields (ELF-MF) during prenatal and neonatal development. These phases of life are characterized by cell proliferation and differentiation, which might make them sensitive to environmental stressors. Although in vitro evidences suggest that ELF-MF may modify the effects of ionizing radiation, no research has been conducted so far in vivo on the genotoxic effects of ELF-MF combined with X-rays. Aim and methods: Aim of this study was to investigate in somatic and germ cells the effects of chronic ELF-MF exposure from mid gestation until weaning, and any possible modulation produced by ELFMF exposure on ionizing radiation-induced damage. Mice were exposed to 50 Hz, 65 μT magnetic field, 24 hours/day, for a total of 30 days, starting from 12 days post-conception. Another group was irradiated with 1 Gy X-rays immediately before ELF-MF exposure, other groups were only X-irradiated or sham-exposed. Micronucleus test on blood erythrocytes was performed at multiple times from 1 to 140 days after birth. Additionally, 42 days after birth, genotoxic and cytotoxic effects on male germ cells were assessed by comet assay and flow cytometric analysis. Results: ELF-MF exposure had no teratogenic effect and did not affect survival, growth and development. The micronucleus test indicated that ELF-MF induced a slight genotoxic damage only after the maximum exposure time and that this effect faded away in the months following the end of exposure. ELF-MF had no effects on ionizing radiation (IR)-induced genotoxicity in erythrocytes. Differently, ELF-MF appeared to modulate the response of male germ cells to X-rays with an impact on proliferation/differentiation processes. These results point to the importance of tissue specificity and development on the impact of ELF-MF on the early stages of life and indicate the need of further research on the molecular mechanisms underlying ELF-MF biological effects. © 2015 Udroiu et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Cytotoxicity, genotoxicity and gene expression changes elicited by exposure of human hepatic cells to Ginkgo biloba leaf extract
No full textThe use of Ginkgo biloba leaf extract as nutraceutical is becoming increasingly common. As a consequence, the definition of a reliable toxicological profile is a priority for its safe utilization. Recently, contrasting data have been reported on the carcinogenic potential of Ginkgo biloba extract in rodent liver. We measured viability, Reactive Oxygen Species (ROS), apoptosis, colony-forming efficiency, genotoxicity by comet assay, and gene expression changes associated with hepato-carcinogenicity in human cells of hepatic origin (HepG2 and THLE-2) treated with different concentrations (0.0005–1.2 mg/mL) of Ginkgoselect®Plus. Our analyses highlighted a decrease of cell viability, not due to apoptosis, after treatment with high doses of the extract, which was likely due to ROS generation by a chemical reaction between extract polyphenols and some components of the culture medium. Comet assay did not detect genotoxic effect at any extract concentration. Finally, the array analysis detected a slight decrease in the expression of only one gene (IGFBP3) in Ginkgo-treated THLE-2 cells as opposed to changes in 28 genes in Aflatoxin B1 treated-cells. In conclusion, our results did not detect any significant genotoxic or biologically relevant cytotoxic effects and gross changes in gene expression using the Ginkgo extract in the hepatic cells tested. © 2017 The Author
- …
