Basic genetics and patterns of inheritance
Hung N. Winn, Frank A. Chervenak, Roberto Romero in Clinical Maternal-Fetal Medicine Online, 2021
Performing cytogenetic analysis has become an integral part of many areas of medical practice, including obstetrics, pediatrics, and oncology. Traditional chromosome analysis first involves obtaining a sample of living tissue. This can be blood, skin, amniotic fluid, products of conception, bone marrow, or any viable solid tissue. Blood is the most frequently analyzed tissue for routine chromosome analysis. For blood, the lymphocytes are isolated. For amniotic fluid, the amniocytes are obtained by spinning down the fluid and removing the cell pellet. For solid tissues, the tissue is minced and/or sonicated. For all tissue types, the cells are cultured in tissue culture for 48 to 72 hours. Cell division is arrested at metaphase by the addition of colcemid. The cells are then harvested and placed on a microscope slide. The cell nuclei are ruptured by adding a hypotonic solution, then stained to show the bands, and images of the metaphase chromosome spreads are analyzed. Each chromosome is studied by looking at the banding pattern to identify not only numerical abnormalities, but also structural problems. Newer computerized technology allows karyotype analysis by digital imaging methods. By convention, the 22 autosome pairs are arranged by size, from the largest to the smallest, in four rows, with the pair of sex chromosomes in the lower right corner (Fig. 1). Ideograms are schematic representations of banding patterns used by cytogeneticists to standardize numbering of specific bands (Fig. 2).
Genomic Instability During Aging of Postmitotic Mammalian Cells
Alvaro Macieira-Coelho in Molecular Basis of Aging, 2017
The investigation of Martin et al.87 broadened the analysis of chromosomal stability to include kidney cells. Chromosomal aberrations were determined in the first metaphases of cells isolated from the kidneys of 8-month-old and 40-month-old CB6F1 hybrid (BALB.cNNia x C57BL/6NNia) mice. Colcemid was added to arrest cells in metaphase and 11 different types of aberrations were scored, including chromatid and chromosome gaps, chromatid breaks, double minutes, acentric fragments, pulverization (extreme fragmentation), Robertsonian (whole-arm) translocations, complex exchanges, and chromosomes with three or four arms. The results showed that old kidney cells had a sixfold higher percentage of cells containing chromosome aberrations. The frequency of cells with aberrations was 4.6% for 8-month-old animals, whereas the percentage of cells with one or more aberrations was 27.1% in 40-month-old mice. The age-specific increase in abnormal chromosomes was greatest for the acentric and pulverized types. Martin et al.87 suggested that a single mechanism appears to be insufficient to generate all the atypical chromosomes, but many of the lesions that are produced in the senescent kidney cells could originate from one or more double-strand breaks, e.g., gaps, pulverization, translocations, acentric fragments, etc. These data generalize to a limited extent the findings of Curtis’ laboratory,81–85 but they are more in agreement with the values of Brooks et al.86 who also examined metaphase plates instead of early anaphase-telophase chromosomes. Whereas the previous studies analyzed liver parenchymal cells, it is not clear what types of cells displayed abnormal chromosomes in the kidney studies.87
Molecular Structure and Functions of Collagen
Marcel E. Nimni in Collagen, 1988
These cells behaved like myofibroblasts and seem to represent a reversible modulation of fibroblasts to contractile fibroblasts. These cells were able to elevate a slice of demineralized tooth root, suggesting that the mechanism may play a role in tooth eruption.313 Colcemid and cytochalasin D which depolymerize, respectively, microtubules and microfilaments, inhibited this effect. The microfilaments seem to be the most actively involved of these cytoskeletal structures.314
Evaluation of toxicological and antimicrobial activity of lavender and immortelle essential oils
Published in Drug and Chemical Toxicology, 2021
Aner Mesic, Irma Mahmutović-Dizdarević, Emina Tahirović, Irma Durmišević, Izet Eminovic, Anesa Jerković-Mujkić, Renata Bešta-Gajević
The chromosome aberrations (CAs) test was modified according to Moorhead et al. (1960). Lymphocyte cell cultures were incubated at 37 °C for 72 h. The test concentrations of lavender and immortelle EOs were added to lymphocyte cultures after 48 h of incubation at the following final concentrations: 0.10; 0.20, and 0.30 µl/ml and the cultures incubated for a further 24 h. The test concentrations of lavender and immortelle oils were prepared with 0.1% DMSO and RPMI-1640 medium. In order to arrest the cells at the metaphase stage, at 70 h of incubation, colcemid™ solution (0.2 µg/ml) (Sigma-Aldrich, St. Louis, MO) was added. In all of the experiments, DMSO (0.1%) was used as the solvent control, while untreated culture was the control group. After an incubation period of 72 h, the cells from culture were treated with a hypotonic solution (0.075 M KCl) for 30 min at 37 °C, to lyse the red blood cells, and fixed with a cold methanol/glacial acetic acid fixative (3:1 v/v). The fixation included three changes of the fixative. Pre-fixed lymphocytes were spread onto clean and cooled glass slides, air-dried, stained with 10% Giemsa solution and analyzed under 1000x magnification.
Nonclonal Chromosomal Aberrations in Childhood Leukemia Survivors
Published in Fetal and Pediatric Pathology, 2018
Tong Foh Chin, Kamariah Ibrahim, Tharshanadevasheri Thirunavakarasu, Mohamad Shafiq Azanan, Lixian Oh, Su Han Lum, Tsiao Yi Yap, Hany Ariffin
Peripheral blood (3–5 mL per subject) collected in sodium heparin tubes were cultured in CHANG Medium® (Irvine Scientific, Santa Ana, CA) at 37 °C for approximately 17 h. 100 µL of colcemid (Gibco™, Life Technologies, Grand Island, NY) was added to arrest the cell cycle at metaphase. Cellular morphology was enhanced by adding 0.075 M potassium chloride and fixed using Carnoy’s fixative solution. Cells were dropped on to a chilled precleaned slide at 106 cells/mL. The slide was aged overnight at 70 °C before being immersed in trypsin and Leishman stain to provide distinctive bands in the chromosomes which were later analyzed using CytoVision™ Software (Applied Imaging, Newcastle, UK). Karyotypes were described according to the International System for Human Cytogenetic Nomenclature (ISCN).
An alternative approach for the induction of premature chromosome condensation in human peripheral blood lymphocytes using mitotic Akodon cells
Published in International Journal of Radiation Biology, 2020
Tamizh Selvan Gnana Sekaran, Michelle Ricoul, Patricia Brochard, Cecile Herate, Laure Sabatier
The conventional colcemid-block protocol has been used popularly for analyzing chromosomes. Over decades, the premature chromosome condensation (PCC) technique has been greatly improved for preparation and analysis as a tool for genotoxic studies and biodosimetry. The reference technique consists of fusing mitotic cells with interphase nuclei. Peripheral blood lymphocytes (PBL) are widely used to assess genetic damages in humans because they circulate throughout the body, are easy to collect by non-invasive methods, and are largely available in the pre-DNA synthesis (G0) stage, which makes them appropriate for evaluating the effects of exposure to various environmental agents. In contrast to the ‘gold standard’ cytogenetic approach (dicentric chromosome analysis in metaphase), PCC allows the immediate processing of non-dividing cells and the visualization of interphase nuclei in a condensed chromosome form. Because of this unique property, PCC is extensively used for studies related to genotoxic assays, cell cycle analysis, and the investigation of chromatin condensation dynamics, radiation induced damage, and DNA repair mechanisms (Gotoh and Durante 2006).
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