| Autor: |
Цафарова, Б., Иванова, С., Ходжев, Й., Толчков, В., Янев, Н., Костадинов, Д., Юрукова, В., Миланов, В., Панайотов, С. |
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| Zdroj: |
General Medicine / Obsta Medicina; 2022, Vol. 24 Issue 3, p11-18, 8p |
| Abstrakt: |
Formalin-fixed paraffin-embedded (FFPE) tissues are routinely used in clinical pathology for diagnosis and studying a large number of diseases. Formalin fixation and subsequent paraffin embedding preserve the morphology, cellular structures and details of the tissue, wherefore it is a standard technique for long-term storage of surgical materials. Formalin, however, can damage DNA in cells, resulting in DNA fragmentation, DNA cross-linking, and deamination of cytosine to uracil, leading to transitions. We investigated 20 FFPE pulmonary sarcoidosis biopsies and 19 FFPE surgical tuberculosis materials. DNA was extracted using two different methods - adapted protocol for DNA isolation from FFPE, based on xylol deparaffinization, and a commercial kit - QIAamp DNA FFPE Advanced UNG Kit (Qiagen, Germany). Conventional PCR analysis for the presence of Cutibacterium acnes and Mycobacterium tuberculosis was made using two different primer sets for M. tuberculosis and two for C. acnes. All tested samples, both sarcoid and tuberculous, showed negative PCR products for M. tuberculosis and C. acnes. Only the internal PCR controls - DNA isolated from mycobacterial culture and C. acnes DNA from skin swab were positive. In conclusion, negative results could be a consequence of the long-term treatment of tissue samples with 10% neutral buffered formalin (= 48 hours for surgical materials), leading to the formation of covalent crosslinking (DNA-DNA and DNA proteins). These crosslinks strain the DNA structure, promoting apurinic (AP) sites and single-strand breaks and inhibiting polymerase chain reaction (PCR). Another reason could be the lack of C. acnes or mycobacterial DNA in the tested samples. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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