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Cellular and Molecular Toxicology of Nanoparticles
Published in Vladimir Torchilin, Handbook of Materials for Nanomedicine, 2020
A. Zielińska, D. Santos, J. R. Campos, A. Santini, P. Severino, A. A. M. Shimojo, S. B. Souto, E. B. Souto
Because the incorporation of radioactive histidine is an expensive process, which requires a long incubation time and may be toxic to cells, the other alternative processes have been explored, e.g., the incorporation of bromodeoxyuridine (BrdU), 5-bromo-2′-deoxyuridine in freshly formed cells. The presence of BrdU can be detected by using a specific antibodies or by flow cytometry [55].
Pollution
Published in Brian D. Fath, Sven E. Jørgensen, Megan Cole, Managing Global Resources and Universal Processes, 2020
Vera Lucia S.S. de Castro, Paola Poli
Detection of SCEs in in vitro test requires some means of differentially labeling sister chromatids, and this can be achieved by incorporation of bromodeoxyuridine (BrdU) into chromosomal DNA for two cell cycles.[83,84] Cells in an exponential stage of growth are exposed to the test substance for a suitable period of time; in most cases, 1–2 hr may be effective, but the treatment time may be extended up to two complete cell cycles in certain cases. Cells without sufficient intrinsic metabolic activity should be exposed to the test chemical in the presence and absence of an appropriate metabolic activation system. At the end of the exposure period, cells are washed free of test substance and cultured for two rounds of replication in the presence of BrdU. As an alternative procedure, cells may be exposed simultaneously to the test chemical and BrdU for the complete culture time of two replication cycles.[85] Cells are analyzed in their second posttreatment division, ensuring that the most sensitive cell cycle stages have been exposed to the chemical. Cell cultures are treated with a spindle inhibitor (e.g., colchicine) 1–4 hours prior to harvesting. Chromosome preparations are made by standard cytogenetic techniques. Staining of slides to show SCEs can be performed by several techniques (e.g., the fluorescence plus Giemsa method).[85,86]
Relevance of mouse lung tumors to human risk assessment
Published in Journal of Toxicology and Environmental Health, Part B, 2020
Samuel M. Cohen, Yan Zhongyu, James S. Bus
There are numerous chemicals that increase the incidence of lung tumors in long-term bioassays in mice but not rats. The mode(s) of action for mouse lung specific carcinogens is oriented to those substances increasing early stage bronchioloalveolar cell proliferation. Enhanced cell proliferation might be attributed to mitogenicity and/or cytotoxicity (cell death) with consequent regenerative proliferation. Elevated cell proliferation may be sensitively detected using BrdU or Ki-67 labeling indices by immunohistochemistry. Thus, short-term evaluation for increased cell proliferation (which is also elevated for DNA-reactive chemicals at high doses) might be employed to screen for potential mouse lung carcinogens without the need for conducting long-term bioassays. If positive in the short-term screen, detailed evaluation of metabolism and mode of action, appropriateness of doses, and detailed evaluation of the dose-response might be assessed for determination of human qualitative or quantitative risk relevance.
It's not just about protein turnover: the role of ribosomal biogenesis and satellite cells in the regulation of skeletal muscle hypertrophy
Published in European Journal of Sport Science, 2019
Matthew Stewart Brook, Daniel James Wilkinson, Ken Smith, Philip James Atherton
Historical measures of DNA and RNA synthesis used radiolabeled pyrimidine analogues such as 3H-thymidine or BrDU (Waldman et al., 1991). However due to their highly toxic nature and the ability to alter cell proliferation in vivo, there use has been limited (Asher et al., 1995). Stable isotope tracers offer an attractive alternative, being safe for human use and (in most cases) have the same chemical behaviour as their naturally abundant cousin with their use in in vivo metabolism is far reaching (Wilkinson et al., 2017). There are many sites for potential stable isotope incorporation during nucleotide synthesis, however ∼80–90% of deoxyribose arises from extracellular glucose providing a route for continuous reliable uptake of an isotopically enriched compound (Neese et al., 2002). For instance by using labelled glucose the turnover of a range of blood cells has been made (Macallan et al., 2009); however due to the need to maintain a constant ingestion or intravenous infusion of stable isotopically labeled glucose, these techniques are only useful for fast turning over cell populations i.e. 24–48 h (Macallan et al., 2009). However, for cells with much slower proliferation rates, such as that of the SC of post-mitotic skeletal muscle cells, an alternative technique is required, and recent novel developments in the application of the “universal” stable isotope tracer deuterium oxide (D2O) has led to great step forward in this field (Brook et al., 2017b).
Learning, memory deficits, and impaired neuronal maturation attributed to acrylamide
Published in Journal of Toxicology and Environmental Health, Part A, 2018
Seulah Lee, Hee Ra Park, Joo Yeon Lee, Jung-Hyun Cho, Hye Min Song, Ah Hyun Kim, Wonjong Lee, Yujeong Lee, Seung-Cheol Chang, Hyung Sik Kim, Jaewon Lee
To detect newly generated cells, free-floating brain sections were treated with 0.6% hydrogen peroxide (H2O2) solution in Tris-buffered saline (TBS) to block endogenous peroxidase, then with 50% formamide/50% sodium citrate buffer for 2 h at 65°C and 2 N HCl for 30 min at 37°C to denature DNA (Lee, Serrogy, and Mattson 2002). Sections were then neutralized by exposing them to 0.1 M borate buffer (pH 8.5) for 15 min, blocked in TBS/0.1% Triton X-100/3% goat serum (TBS-TS) for 30 min and incubated with primary anti-BrdU antibody (Abcam, Cambridge, MA, USA) in TBS-TS overnight at 4°C. Tissues were then treated with a biotinylated secondary goat anti-rat IgG antibody (3 μl/ml, Vector Laboratories, Burlingame, CA, USA) for 3 h at room temperature, with ABC solution (avidin-peroxidase complex, Vectastain ABC reagent Elite Kit, Vector Laboratories) at room temperature for 1 h, stained with diaminobenzidine (DAB) solution for 5 min, mounted, and cover slipped. Images were taken using a Nikon ECLIPSE TE 2000-U microscope (Nikon). BrdU positive cells were counted in every sixth section throughout the entire rostro-caudal extents of hippocampi. The granule cell layer of dentate gyrus was used as a reference region. All cell counts were performed by the same blinded investigator.