tailieunhanh - Báo cáo khoa học: " Effect of fixation time and freeze-thaw cycles on the molecular analysis of viral DNA"

Tuyển tập các báo cáo nghiên cứu khoa học quốc tế về bệnh thú y đề tài: Effect of fixation time and freeze-thaw cycles on the molecular analysis of viral DNA | J. Vet. Sci. 2003 4 2 203-204 JOURNAL OF Veterinary Science - Short Communication - Effect of Fixation Time and Freeze-thaw Cycles on the Molecular Analysis of Viral DNA Ok-jin Kim United States Department of Agriculture-ARS Animal Disease Research Unit Received May 20 2003 Accepted July 13 2003 Abstract This study was done to determine the effect of fixation time and freeze-thaw FT cycles on the quantitation and positivity of viral DNA There were significant decreases in the viral DNA copies in the specimens subjected to formalin fixation more than 24 hours. However The viral DNAs of specimens with FT cycles were not remarkably decreased as compare with those of fresh samples. These results implicate that there may be need to fix the samples less than 24 hours. Also results of retrospective studies performed on specimens subjected to long-term fixation may be compromised. Key words formalin freeze-thaw stability viral DNA In practice clinical specimens may be fixed or frozen after collection for long-term storage and then the fixed tissues for which formalin is a main fixative in the field of pathology may be submitted to paraffin embedding for pathological examination. Also the frozen specimens may be thawed and refrozen numerous times for analysis. Recently molecular methods for viral nucleic acid detection have become essential tools in the field of diagnostic pathology 2 . To ensure optimal prognostic value of viral nucleic acid measurements it is necessary to understand the stability of viral DNA in specimens subjected to formalin fixation and to freeze-thaw FT conditions 3 . Furthermore researchers planning retrospective studies employing fixative tissues or frozen specimens must know the impact of fixation time and multiple FT cycles on the stability of viral nucleic acid in specimens. This study was done to determine the effect of fixation time and freeze-thaw cycles on the quantitation and positivity of herpesvirus DNA. For this study the cultured cells .