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Cytogenetics of Colorectal Cancer
Published in Leonard H. Augenlicht, Cell and Molecular Biology of Colon Cancer, 2019
For spontaneous and clastogen-induced aberrations, we harvest the blood culture after 72 h of incubation with 1-h treatment of Colcemid (0.04 μg/ml) prior to termination. KC1 (0.075 M) is used as the swelling solution for 20 to 25 min at 37°C. Hypotonically treated cells are fixed in methanol and acetic acid (3:1 by vol), washed four times in the fixative, and finally air-dried on acetone-cleaned slides. For prophase chromosome morphology, we use the technique of Yunis59 or sometimes the procedure described by Rybak et al.70
Motoo Kimura (1924–1994)
Published in Krishna Dronamraju, A Century of Geneticists, 2018
According to his collaborator in population genetics, Dr. James Crow, Kimura used the royalties from their book to build a small greenhouse to grow orchids. Every Sunday was spent looking after his orchids. He was encouraged to study chromosome morphology by his high school teacher. Kimura decided to become a plant cytogeneticist.
Molecular Genetic Diagnosis of Human Malignant Hyperthermia
Published in S. Tsuyoshi Ohnishi, Tomoko Ohnishi, Malignant Hyperthermia, 1994
Syndromes characterized by growth delay, mental retardation, and a variety of somatic and structural abnormalities may be attributed on occasion to chromosome aberrations visible with light microscopy. Abnormal expression of multiple contiguous genes in the deleted, duplicated, or translocated chromosome segment explains these diverse features. If a hereditary trait such as MH is also associated with a syndrome produced by a cytogenetic abnormality, it is likely that the gene responsible for the trait resides in the aberrant segment and may also underlie the trait in families lacking the dysmorphic syndrome. Thus the retinoblastoma and dystrophin genes were assigned to their respective loci on chromosomes 13 and X26,27 by changes in chromosome morphology detected in rare patients with multiply affected genes.
Multifaceted applications of pre-mature chromosome condensation in radiation biodosimetry
Published in International Journal of Radiation Biology, 2020
Usha Yadav, Nagesh Nagabhushana Bhat, Kapil Bansidhar Shirsath, Utkarsha Sagar Mungse, Balvinder Kaur Sapra
G0-PCC technique utilizes the property of mitotic factors present in CHO cells to dissolve the nuclear membrane and prematurely condense the interphase chromatin of unstimulated human lymphocytes. The resulting spreads can be analyzed for chromosomal aberration analysis in lymphocyte chromosomes to estimate the absorbed radiation dose. In PCC spreads, CHO chromosomes are distinguishable from that of human lymphocytes with their typical metaphase chromosome morphology having two distinct chromatids and centromeric constriction. First report on the application of G0-PCC for biodosimetry came in 1984 (Pantelias and Maillie 1984). Despite the distinct advantages of G0-PCC over the conventional methods, studies using G0-PCC are highly restricted in the literature, as this technique requires a great deal of expertise and optimizations. Recently, there has been a rejuvenated interest and focus on G0-PCC to overcome challenges in biodosimetry (Bezrookove et al. 2003; Hatzi et al. 2006; Lamadrid Boada et al. 2013; Suto et al. 2013; Karachristou et al. 2015; Neronova 2016; Terzoudi et al. 2017; Ryan et al. 2019). A recent study demonstrated utility of the method in large scale accident with small volume of 100 µl of blood in 96 well plate (Pantelias and Terzoudi 2018).
Precision of scoring radiation-induced chromosomal aberrations and micronuclei by unexperienced scorers
Published in International Journal of Radiation Biology, 2019
Maciej Gałecki, Adrianna Tartas, Agata Szymanek, Emma Sims, Lovisa Lundholm, Alice Sollazzo, Lei Cheng, Yohei Fujishima, Mitsuaki A. Yoshida, Jarosław Żygierewicz, Andrzej Wojcik, Beata Brzozowska-Wardecka
Analysis of cytogenetic damage remains a basic endpoint for studying the effects of ionizing radiation in cells. Cytogenetic damage can be visualized as structural changes of chromosome morphology called chromosomal aberrations (CA) or as micronuclei (MN) which are small-sized nuclei containing lagging chromosomes or chromosomal fragments. Radiation-induced CA were initially studied in plant cells (Lea and Catcheside 1942) and their identification and analysis in mammalian cells only became possible following the development of appropriate cell culturing and harvesting methods (Tjio and Levan 1956; Holmquist and Motara 1987). In 1962 Bender and Gooch discovered that the quantitative analysis of CA in peripheral blood lymphocytes can serve as a reliable retrospective dosimeter (Bender and Gooch 1962). Subsequent work established the CA test as the gold standard of biological dosimetry (Romm et al. 2009; Ainsbury et al. 2011; IAEA 2011). MN were observed by Howell as early as 1891 and by Jolly in 1907 (Müller and Streffer 1994), but their application in mammalian cell radiation biology was pioneered by Countryman and Heddle in 1976 (Countryman and Heddle 1976). The effective use of the MN assay for quantifying radiation-induced DNA damage was made possible by Fenech and Morley who discovered that cytochalasin B prevents cytokinesis while allowing karyokinesis (Fenech and Morley 1985). The cytokinesis block micronucleus (CBMN) assay is routinely used for biological dosimetry in parallel or instead of the chromosomal aberration assay (IAEA 2011).
Chromosomal microarray analysis detects trisomy 9 mosaicism in a prenatal case not revealed by conventional cytogenetic analysis of cord blood
Published in Journal of Obstetrics and Gynaecology, 2019
Hai-Shen Tang, De-Gang Wang, Lv-Yin Huang, Dong-Zhi Li
Chromosomal mosaicism is a biological phenomenon that is defined by the presence of two or more chromosomally different cell lines in an individual. In cytogenetic prenatal diagnosis, it mainly involves full aneuploidies or, more rarely, structural rearrangements (Grati et al. 2017). The standard cytogenetic technique, or karyotyping, is able to demonstrate the distribution of the abnormal cell lines and the chromosome morphology. This data has important practical implications for counselling management. New methods have recently become available to detect mosaicism. In particular, the chromosomal microarrays (CMA) technique can bypass the need for culturing and the results can be given in a timely manner. This approach has the advantage of detecting the microdeletions/microduplications and low-level mosaicism that are usually beyond the ability of traditional karyotyping (Filges et al. 2011; Karampetsou et al. 2014). We hereby report a prenatal case of trisomy 9 mosaicism in which routine karyotyping and CMA have discordant results based on the testing of foetal blood.