Field emission SEM and back-scattered electron imaging of microwave silver-stained bacterial lipopolysaccharide on clinical slides of septic patients

Abstract

Several stains have emanated from the classic work of Hanker et al. which provide highly visable and electron opaque end products. These allow back-scattered electron imaging (BEI) and visualization of polymerized 3, 3'-diaminobenzidine (DAB) or p-phenylenediamine/pyrocatechol (PPD/PC) on endogenous enzyme or nonenzyme hemoproteins, or visualization of exogenous horseradish peroxidase (HRP) transported in tissue or attached to cells, or immunoperoxidase localized to tissue antigen or receptor sites. Additionally, the Giammara-Hanker PATS reaction (Pat.Appl. No. 08/225,058), originally used to show biomacromolecules or structures such as glycogen, basement membranes, reticular fibers or lipopolysaccharide, appears to be a positive stain for Gram (-) bacteria, including spirochetes, as well as for neutrophils and activated macrophages. The PATS reaction also demonstrates sites of calcification in tissues and certain calcium compounds by both light and electron microscopy. Likewise, an improved FETS reaction uses silver as an electron opaque Feulgen-type reaction for DNA and demonstrates DNA in bacteria and Candida albicans as well as other cellular nuclei.