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Micronucleus assay and oral hygiene index in smokers
Published in Ade Gafar Abdullah, Isma Widiaty, Cep Ubad Abdullah, Medical Technology and Environmental Health, 2020
M.M. Damayanti, Y. Kharisma, I.M. Nur, M. Rachmawati, A.H. Hasan, F.A. Yulianto, S.B. Rahimah, W. Maharani
Smoking changes the structure of oral tissue. Many researchers have reported a significant correlation between smoking and an increase in the frequency of micronuclei and other nuclear abnormalities. The nicotine in cigarettes is one of the genotoxic compounds that will convert nitrosation into nitrosamine, which can damage the DNA. DNA damage due to genotoxic exposure can manifest as micronuclei, a second cell nucleus that is smaller than the real nucleus cell (Farhadi et al. 2016; Rahmah et al. 2016).
Preimplantation Genetic Testing for Aneuploidies: Where We Are and Where We're Going
Published in Darren K. Griffin, Gary L. Harton, Preimplantation Genetic Testing, 2020
Andrea Victor, Cagri Ogur, Alan Thornhill, Darren K. Griffin
Mosaicism was first documented in human embryos with FISH [3,4,52,114]. Since then, a number of different mitotic error mechanisms have been proposed to explain mosaicism: mitotic nondisjunction, anaphase lagging, formation of multinuclei and/or micronuclei, centriole/centrosome dysregulation, and endoreplication [102,115–117]. Mitotic nondisjunction means that sister chromatids of a chromosome are not correctly separated during cell division, resulting in one trisomic and one monosomic daughter cell. Anaphase lagging is an event leading to monosomy in one of the daughter cells at mitosis, because a chromatid does not become incorporated into the nucleus. In mosaic embryos, there is a documented increased incidence of monosomies compared to trisomies, suggesting that anaphase lagging might be the principal mechanism creating mosaicism [12,118,119]. Micronuclei, or small nucleus-like structures, are thought to arise when chromosomal material forms its own nuclear membrane. Since proper kinetochores are absent, the chromosomal content of micronuclei are unable to undergo regulated mitosis, likely resulting in mosaicism in daughter cells [116,120]. Finally, endoreplication without subsequent division could hypothetically result in mosaicism but has not been documented for individual chromosomes, but rather for entire chromosomal complements [115].
Hazard Characterization and Dose–Response Assessment
Published in Ted W. Simon, Environmental Risk Assessment, 2019
Genotoxicity is the ability of substances to damage DNA and/or cellular components regulating the fidelity of the genome—such as the spindle apparatus, topoisomerases, DNA repair systems, and DNA polymerases. The oldest, least expensive, and least predictive test is the bacterial reverse mutation assay, or Ames Test. The in vitro micronucleus test uses mammalian cell lines or cultures of primary human cells and looks for micronuclei or chromosomal aberrations. Micronuclei are infrequent third nuclei formed during cell division that contain chromosome fragments. The dose-dependent frequency of micronuclei suggests potential genotoxicity. In vivo genotoxicity tests are most often performed in transgenic animals and look for specific effects depending on the transgenic species.157
Genotoxic potential of different nano-silver halides in cultured human lymphocyte cells
Published in Drug and Chemical Toxicology, 2023
Devrim Güzel, Merve Güneş, Burçin Yalçın, Esin Akarsu, Eyyüp Rencüzoğulları, Bülent Kaya
The genotoxicity of a chemical can be determined through several changes in the structure of the DNA, such as induction of chromosomal aberrations, changes in the micronucleus (MN) structure and cell cycle process inhibition (Ginzkey et al.2014). These alterations are determined through genotoxicity tests to unveil the effects of various genotoxic agents on human lymphocytes. The MN assay is one such test that has been routinely used to screen for genotoxic agents, indicating chromosome damage and loss. Micronuclei may result from aneugenic (whole chromosome) or clastogenic (chromosome breakage) damage (Fenech 2000). The other means of testing is the chromosome aberration (CA) test, which has been developed to identify genotoxic or carcinogenic agents that cause structural CA in cultured mammalian cells (Johannes and Obe 2013).
Genotoxicity evaluation of self-assembled-micelle inhibitory RNA-targeting amphiregulin (SAMiRNA-AREG), a novel siRNA nanoparticle for the treatment of fibrotic disease
Published in Drug and Chemical Toxicology, 2022
Hyeon-Young Kim, Tae Rim Kim, Sung-Hwan Kim, In-Hyeon Kim, Youngho Ko, Sungil Yun, In-Chul Lee, Han-Oh Park, Jong-Choon Kim
The results of the micronucleus assay are presented in Tables 3 and 4. No abnormal clinical signs and unscheduled death were observed in the mice after the first and final administration in the vehicle control, positive control, and SAMiRNA-AREG treatment groups (data not shown). Body weight also showed no significant differences between the vehicle control and the SAMiRNA-AREG treated groups (Table 3). As shown in Table 4, there were no significant changes in the MNPCEs and PCEs/(PECs + NCEs) ratio in the SAMiRNA-AREG-treated groups compared to those in the vehicle control group in both sexes. The incidence of MNPCEs in the vehicle control group was within the range of historical control data. On the contrary, there was a significant increase in the number of MNPCEs in the positive control group compared to that in the vehicle control group. In addition, the ratio of PCEs/(PCEs + NCEs) was significantly decreased in female mice of the positive control group. However, no significant changes in the PCEs/(PCEs + NCEs) ratio were observed in the male mice of the positive control group.
Assessment of genotoxicity of glass ionomer cements: a systematic review
Published in Critical Reviews in Toxicology, 2022
Ingra Tais Malacarne, Wilton Mitsunari Takeshita, Daniel Vitor de Souza, Marcia Regina Nagaoka, Odair Aguiar Jr., Ana Claudia Muniz Renno, Daniel Araki Ribeiro
The single-cell (comet) gel assay is a reliable method for evaluating DNA strand breakage. This is a simple method that allows the reliable analysis of complex genetic damage that can originate from dental compounds (Wawrzynkiewicz et al. 2021). In turn, the micronucleus test is a sensitive assay for the detection of chromosomal damage (Malacarne et al. 2021). The analysis by sister chromatid exchange and chromosomal aberrations were useful in the evaluation of biomarkers in mutagenesis, demonstrating an early genotoxic behavior of therapeutic materials (Pettini et al. 2015). Therefore, we observed in the included studies that they immediately direct the action of the materials by cytotoxicity tests and focused on long-term effects by tests that evaluated the possible genotoxic damage followed or not by mutations.