Ultrasound-accelerated Tissue Fixation/Processing Achieves Superior Morphology and Macromolecule Integrity with Storage Stability
Wei-Sing Chu 1*, Qi Liang 1, Yao Tang 1, Randy King 1, Kondi Wong 1, Maokai Gong 1, Minqi Wei 1, Jilan Liu 1, Shaw-Huey Feng 1, Shyh-Ching Lo 1, Jo-Ann Andriko 1 and Marshall Orr 1
1 Department of: Scientific Laboratories (W-SC,QL,RK,MG,MW,JL), Neuropathology and Ophthalmic Pathology (KW), and Infectious and Parasitic Diseases Pathology (S-HF,S-CL), Armed Forces Institute of Pathology, Washington, DC; Department of Pathology, Walter Reed Army Medical Center, Washington, DC (J-AA); Naval Research Laboratory, Washington, DC (MO); and Cancer Center, University of Maryland School of Medicine, Baltimore, MD (YT)
* To whom correspondence should be addressed. E-mail: chu{at}afip.osd.mil.
Submitted on August 2, 2005
Accepted on 8 November 2005
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Abstract |
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We demonstrate that high-frequency and high-intensity ultrasound can be applied to both tissue fixation and tissue processing, to complete the conventional overnight formalin-fixation and paraffin-embedding (FFPE) procedures within 1 hr. US-facilitated FFPE retains superior tissue morphology and long-term room-temperature storage stability as conventional FFPE. There is less alteration of protein antigenicity after US-FFPE preservation, so that rapid immunohistochemical reactions occur with higher sensitivity and intensity, reducing the need for antigen retrieval pretreatment. US-FFPE tissues present storage stability so that room-temperature storage up to 7 years does not significantly affect tissue morphology, protein antigenic properties, RNA distribution, localization and quantitation. In addition, during fixation, tissue displays physical changes that can be monitored and reflected as changes in transmission ultrasound signals. As far as we know, this is the first effort to monitor tissue physical changes during fixation. Further study of this phenomenon may provide a method to control and monitor the level of fixation for quality controls. The mechanism of less alteration of protein antigenicity by US-FFPE was discussed.
Key Words:
ultrasound, formalin fixation, tissue processing, immunohistochemistry, RNA extraction, storage stability