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Gene Rearrangement in Leukemias and Lymphomas
Published in John T. Kemshead, Pediatric Tumors: Immunological and Molecular Markers, 2020
The sensitivity of the technique can result in artifacts: incomplete digestion of DNA with restriction enzymes; contamination of the samples with bacterial or plasmid DNA; and inadequate transfer of the fragments to the filter may all result in misleading data. The recombinant DNA probes used must be well characterized to ensure the validity of the results obtained.
The Genetic Body
Published in Roger Cooter, John Pickstone, Medicine in the Twentieth Century, 2020
Over the period of planning and debate in the US, the idea of a project spread to a number of other countries. In early 1991 a world-wide survey of genome mapping activities published by the UK Medical Research Council listed eight countries with established national genome projects (Denmark, France, Germany, Italy, UK, Japan, USSR and US) and a further seven which had made moves to instigate national programs (Australia, Netherlands, Canada, Chile, Sweden, Korea and New Zealand) although not all were successful. In addition, international programs had been instigated or proposed by the EC, UNESCO, Latin-America and the Nordic countries. World-wide co-ordination, but not research funding, of the initiative was undertaken by the Human Genome Organization (HUGO), established in 1988 with its headquarters in Geneva. In the absence of an overarching program, the international effort is best conceived of as a loose confederacy of programs. And the association with advances in medical understanding was reinforced by a series of discoveries of single genes, which in altered form were responsible for conditions as varied as cystic fibrosis, Huntington’s disease and muscular dystrophy. Genes associated with some cases of more common conditions — breast cancer, Alzheimer’s disease, diabetes and arthritis — also followed, together with claims (often subsequently retracted) to have located gene loci influencing susceptibility to schizophrenia, depression, and alcoholism. Diagnostic tests using DNA probes from these genes soon began to appear.
Sexually transmitted infections in adolescents
Published in Joseph S. Sanfilippo, Eduardo Lara-Torre, Veronica Gomez-Lobo, Sanfilippo's Textbook of Pediatric and Adolescent GynecologySecond Edition, 2019
Infections with the single-celled protozoan T. vaginalis are common among adolescent girls. Infection may be asymptomatic or may be characterized by a frothy, malodorous vaginal discharge and vulvar irritation. Trichomoniasis has been associated with increased risk of HIV transmission and adverse pregnancy outcomes.19,20 The motile, flagellated organisms may be seen with light microscopy, but the sensitivity of this diagnostic modality is low. NAAT may be performed on urine or vaginal specimens with excellent sensitivity; culture and rapid testing also perform well.21 Nonamplified DNA probe testing has poor sensitivity for this infection.22 Treatment is with oral nitroimidazoles (Table 17.1); topical treatment will not reliably eradicate the infection. For patients with persistent symptoms, reinfection is believed to be the most likely cause, but antimicrobial resistance has been described. If true treatment failure is suspected following single-dose therapy, a course of metronidazole 500 mg twice daily should be used. CDC provides additional treatment options with high-dose nitroimidazoles and is available for consultation in the management of persistent infections.10
The current and future applications of in situ hybridization technologies in anatomical pathology
Published in Expert Review of Molecular Diagnostics, 2022
Hoi Yi Leung, Martin Ho Yin Yeung, Wai Tung Leung, King Hin Wong, Wai Yan Tang, William Chi Shing Cho, Heong Ting Wong, Hin Fung Tsang, Yin Kwan Evelyn Wong, Xiao Meng Pei, Hennie Yuk Lin Cheng, Amanda Kit Ching Chan, Sze Chuen Cesar Wong
Lin et al. [67] developed amplification-based single-molecule FISH (asmFISH) which is the combination of a modified smFISH with RCA. First, a pair of DNA probes is used to target the RNA molecule of interest. The probe is then ligated to the RNA by enzymatic reaction, forming a circular DNA for signal amplification via RCA. Lastly, fluorescently labeled probes are hybridized to the amplified DNAs and detected by microscopy. To test the applicability of asmFISH to detect gene expression, HER2 expression in two breast cancer cell lines, MCF-7 and SK-BR-3, were measured. The results matched with the human protein atlas database, therefore, asmFISH could show the difference in levels of gene expression. It also had a higher capacity in discriminating SNPs compared to in situ padlock probe assay. The author demonstrated that asmFISH is applicable in both FFPE and fresh frozen tissue samples, showing the potential in clinical application.
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
For the detection of dicentric chromosomes, G0-PCC spreads from irradiated samples were hybridized with centromere specific Peptide Nucleic acid (PNA) probe. Since the centromeric regions are not clearly visible in prematurely condensed chromosomes, FISH with centromeric probe offered an advantage for visualizing dicentric chromosomes. The chromosomal bodies with one, two or no centromeres were clearly visible as shown in Figure 3(d). Besides, excess fragments are not usually considered as radiation specific compared to dicentrics. Hence demand for radiation specific dicentric signal can be met with G0-PCC using PNA-FISH probes even when conventional DCA is not feasible. These probes are more economical than conventionally available DNA probes. The centromeres staining allow quantification of dicentrics. Dicentric based dose estimations are expected to be more accurate as it is well established that dicentrics are most radiation specific markers with low background frequency and low inter-individual variation. Dicentric is known as gold standard for biodosimetry. Dicentric detection using this method is also important for high doses or high LET exposures wherein a big proportion of cells fail to reach metaphases and thus actual dose estimation can be difficult. There are few reports recently been published on dicentric detection with G0-PCC (Karachristou et al. 2015; M’kacher et al. 2015).
Detection of DNA damage in pigeon erythrocytes using a chromatin dispersion assay
Published in Toxicology Mechanisms and Methods, 2020
Elva I. Cortés-Gutiérrez, Juan A. García-Salas, Martha I. Dávila-Rodríguez, Juan P. Ceyca-Contreras, Michel Cortez-Reyes, José L. Fernández, Jaime Gosálvez
The DNA breakage detection–fluorescence in situ hybridization (DBD-FISH) technique is very sensitive and enables cell-by-cell detection and evaluation of DNA ruptures in whole genome or within precise DNA sequences. After removing the proteins, DNA probes are hybridized and detected. We found earlier that the analysis of erythrocytes from pigeon using DBD-FISH provided a sensitive and reliable test for detecting DNA breaks (Cortés-Gutiérrez et al. 2019). Columba livia has been suggested as a sentinel for assessing the repercussion of air pollutants on urban human populations (Kleinjans and van Schooten 2002; Sicolo et al. 2009). However, microelectrophoretic and FISH methods for assessing DNA damage are time-consuming and require costly and specialized equipment, as well as technical ability (Stricklin et al. 2007; Pereira de Lemos Pinto et al. 2010).