All, The formic acid is a post-fixation step.
http://www.cdc.gov/od/ohs/biosfty/bmbl4/bmbl4s7d.htm#Table%205.%20Tissue %20preparation Jeanine Bartlett, BS, HT(ASCP)QIHC Centers for Disease Control and Prevention Infectious Diseases Pathology Branch 1600 Clifton Road, MS/G-32 18/SB-114 Atlanta, GA 30333 (404) 639-3590 jeanine.bartl...@cdc.hhs.gov -----Original Message----- From: histonet-boun...@lists.utsouthwestern.edu [mailto:histonet-boun...@lists.utsouthwestern.edu] On Behalf Of joelle weaver Sent: Thursday, January 22, 2009 6:46 PM To: sal...@exchange.hsc.mb.ca; Histonet Subject: RE: [Histonet] RE: Prion Contamination I just researched this recently for procedure writing. I referenced an article from the CDC that made mention of specific handling guidelines for histology, and also specifically the formic acid treatment step. I do not have the article in front of me, but by my recollection I believe that it stated that the formic acid was a post-fixation step. I found this article relatively easily by using the search field for CJD from the CDC website. You can check my recollection here: http://www.cdc.gov/od/ohs/biosfty/bmbl5/sections/SectionVIIIH-PrionDisea ses.pdf Thanks Joelle Weaver HTL(ASCP) > Date: Thu, 22 Jan 2009 13:21:25 -0600> From: > sal...@exchange.hsc.mb.ca> To: tbr...@holyredeemer.com> Subject: > [Histonet] RE: Prion Contamination> CC: > histonet@lists.utsouthwestern.edu> > Hi,> I was reading your email of > Jan. 15/09 on the subject of "Prion> Contamination". In it you had > made the following statement, which I was> curious as to where this > information had come from. > "the procedure to inactivate using formic > acid is followed before> fixation and processing. If the tissue is > fixed (formalin or other> common fixatives) then you would be actually > "fixing" the prion's> ability to NOT be inactivated". > I had read > again the WHO Guidelines on CJD that you had a link to &> could find > no mention of the fact that the formic acid step for> de-activating > the prions had to be done before any fixation. The WHO> instructions: > P. 18 8.2.2 Histopathological examination: states "formic> acid > treatment consists of placing small pieces of fixed tissue, no more> > than 4 to 5 mm thick, in 50 to 100 ml of 95% formic acid for an hour". > I> have been dealing with CJD brains for many years always following > the> CDC, WHO & Health Canada guidelines but have never read any > studies that> had indicated that the fixing in formalin made the > treatment in formic> acid ineffective. If you have any further > information I would really> appreciate seeing it. > Thank you > S. > Allen> sal...@hsc.mb.ca> > _________________________________________________________________ Windows Live(tm): E-mail. Chat. Share. Get more ways to connect. http://windowslive.com/explore?ocid=TXT_TAGLM_WL_t2_allup_explore_012009 _______________________________________________ Histonet mailing list Histonet@lists.utsouthwestern.edu http://lists.utsouthwestern.edu/mailman/listinfo/histonet _______________________________________________ Histonet mailing list Histonet@lists.utsouthwestern.edu http://lists.utsouthwestern.edu/mailman/listinfo/histonet