IMPROVED LIPID VISUALIZATION WITH A MODIFIED OSMIUM-TETROXIDE METHOD USING ULTRASONIC TREATMENT AND INTENSIFICATION WITH IMIDAZOLE OR TRIAZOLE

Formalin fixed autopsy tissue containing lipids were cut into 1-5 mm t hick blocks, washed well, then postfixed in 2% OsO4 in 0.03 M veronal acetate buffer for 30, 60, 90, 120, or 180 min with or without ultraso nic treatment. Tissues exposed to ultrasound for 90 min showed superio r penetration of OsO4 and well preserved histological architecture. Ti ssues also were immersed for 1 hr in veronal acetate buffer (pH 7.4) c ontaining 0.5% imidazole or triazole and compared with untreated contr ols. Paraffin sections, 4 mu m thick, were examined under a light micr oscope with an image analyzer. Both intensity and percentage area of o smium blackening were significantly higher in samples immersed in imid azole or triazole than in untreated controls. No difference was observ ed between imidazole- and triazole-immersed samples. The OsO4 method, modified by ultrasound treatment and imidazole- or triazole-immersion, can be applied to routine formalin fixed autopsy materials for improv ed lipid visualization,