Tissue cytogenetics

In situ hybridization (ISH) consists of the application of hybridization techniques to intact cells which demonstrate genetic information within a morphologic context. This technology takes advantage of the hybridization properties of nucleic acids and offers a distinct technique to directly analyze sequence information in intact tissues. In essence, it combines cytogenetic techniques with molecular biology to probe gene alterations at molecular levels. Development of... 

Henke, R.-P., and Ayhan, N. 1994. Enhancement of hybridization efficiency in interphase cytogenetics on paraffin-embedded tissue sections by microwave treatment. Analyt. Cell. Pathol. 6 319-325. 

Shakil, F.A., A. Kuramoto, M. Yamakido, et al. 1993. Cytogenetic abnormalities of hematopoietic tissue in retired workers of the Ohkunojima poison gas factory. Hiroshima J. Med. Sci. 42 159-165. 

Safrole has been found to be a weak hepatocarcinogen, which is linked to the formation of safrole-DNA adducts. Safrole treatment will induce oxidative damage in rat hepatic tissue (331) and is a genotoxic carcinogen in rat liver in vivo (332). These cytogenetic effects may result from covalent DNA modification in the rat liver. The threshold cytotoxic concentration found for safrole is 0.10 mug/ml safrole (333). 

Controls. Test all your probes on normal chromosomes prepared from lymphocytes. This is essential no matter what your final application is. In addition, for interphase cytogenetics, use sections from normal tissue. Pay particular attention to specificity of hybridization. Some probes such as chromosome-specific repeat-sequence probes can bind to several chromosomes if the hybridization conditions are not correct. Use commercial probes to test your reagents. 

The answer is d. (Murray, pp 812—828. Scriver, pp 3—45. Sack, pp 57-84. Wilson, pp 123—148.) Mosaicism occurs when a chromosomal anomaly affects one of several precursor cells of an embryo or tissue. The two or more karyotypes that characterize the mosaic cells are separated by a slash in cytogenetic notation. The notation 47,XX,-I-2I denotes a cell line typical of a female with trisomy 21 (Down s syndrome), while 46,XX is the karyotype expected for a normal female. 

Conventional cytogenetic analysis requires fresh tissue. Fluorescence in situ hybridization (FISFI) can be performed on a variety of specimens including frozen... 

Sandberg AA. Updates on the cytogenetics and molecular genetics of bone and soft tissue tumors Liposarcoma. Cancer Genet Cytogenet. 2004 155 1-24. 

Wehle D, Yonescu R, Long PP, et al. Fluorescence in situ hybridization of 12p in germ cell tumors using a bacterial artificial chromosome clone 12p probe on paraffin-embedded tissue clinical test validation. Cancer Genet Cytogenet. 2008 183 99. 

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