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FD-302aRev.10-6-95 b6 279A-WF-222936-USAMRIID, 279A-BA-C101392 b7C 06/06/2003 2 Continuation of FD-302 of On Page of excess formaldehyde. recalled a study conducted by LNU and (phonetic) using tissue embedded with west Nile virus and/paraffin. The aim of the project was to determine the effectiveness of DNA extraction following formalin fixation of the tissue. This method of decontamination did not hinder subsequent DNA amplification; however, proteins within the tissue were affected. A methodology was developed which facilitated the release of formaldehyde from tissue using organic reagents. Oxidation and halogenation of bacterial spores result from exposure to chlorine dioxide gas. Chlorine binds to cellular components yielding inactivation of proteins and enzymes required for cellular arowth. has researched extensively the use of chlorine dioxide as a decontaminant. The intensity of gamma irradiation used for decontamination is typically not enough to nick strands of DNA. However, exposure to gamma rays may damage the DNA and decrease the sensitivity of PcR techniques. Significant amounts of radiation would be necessary to completely abolish a PcR signal. Generally, the degree of DNA chopping depends on the extent and intensity of. exposure. DNA has also been shown to survive the autoclaving method of decontamination. Latent fingerprints are lipid imprints which may be destroyed by alcohols, detergents and physical wiping. Gamma irradiation was not known to affect the detection of latent. fingerprints. and were not aware of studies to determine the effects of formaldehyde vapor, chlorine dioxide,. and hydrogen peroxide on the detection of latent fingerprints.. Bacterial spores are more resistant than vegetative cells to decontamination efforts. Generally, the effectiveness of disinfection depends on the concentration of the decontaminant and the length of exposure. Often, post-decontamination analyses yield negative culture results and positive PcR hits. These results indicate the absence of detectable levels of viable microorganisms, but the presence of characteristic DNA. When testing for the presence of microorganisms, it is important to test first for viability via culturing, followed by confirmation analyses using. PCR. indicated that sA was familiar with post-decontamination tests of biosafety cabinets treated with.