Enhancer Formalin

In the early 1900s, a balanced mixture of diphtheria toxin and antitoxin was found to produce active immunity in both animals and humans. This preparation gained widespread acceptance and protected approximately 85% of recipients. Several years later, diphtheria toxoid was developed by treating the toxin with small amounts of formalin. This process caused the toxin to lose its toxic properties while maintaining its immunogenic properties. In the mid-1920s, the addition of an alum precipitate enhanced the immunogenic properties of the toxoid. 

Shi SR, Key ME, Kalra KL. Antigen retrieval in formalin-fixed, paraffin-embedded tissues an enhancement method for immunohistochemical staining based on microwave oven heating of tissue sections. J. Histochem. Cytochem. 1991 39 741-748. 

A simple and effective AR technique of boiling archival paraffin-embedded tissue sections in water to enhance the signal of IHC was developed to circumvent the deleterious effects of formalin fixation, which had previously... 

Shin RW, Iwaki T, Kitamoto T, et al. Hydrated autoclave pretreatment enhances tau immunoreactivity in formalin-fixed normal and Alzheimer s disease brain tissues. Lab. Invest. 1991 64 693-702. 

Abbondanzo SL, Allred DC, Lampkin S, et al. Enhancement of immunoreactivity in paraffin embedded tissues by refixation in zinc sulfate-formalin. Proc. Annual Meeting US and Canadian Acad. Pathol. Boston March 4-9, 1990. Lab. Invest. 

Interactions are seen between cocaine and the opioid system in analgesia. A synergistic effect occurs when cocaine is combined with a ju agonist (morphine) in the hot-plate test and a k agonist (U69,593) in the hot-plate test (Waddell and Holtzman 1999). Cocaine enhances morphine analgesia in several analgesic paradigms (e.g., formalin test, hot-plate test, and thermal tail-flick test)... 

The enhanced peroxidase one-step (EPOS) method is considered superior to standard ABC technique in that the former is more sensitive than the latter. It is known that the Ki-67 antibody can only be used on fresh or frozen tissues, whereas the monoclonal antibody MIB-1, developed against a part of the Ki-67 antigen molecule, can be used on sections of formalin-fixed and paraffin-embedded tissues using antigen retrieval. Recently, EPOS Ki-67 antibodies were developed which consist of antibody molecules and horseradish peroxidase bound covalently to dextran (Bisgaad et al., 1993). This method has been applied for localizing PCNA and Ki-67 antigens (Tsutsumi et al., 1995). 

Surgically removed tissues are fixed with 4% buffered formalin and embedded in paraffin (Turner et al, 1999). Sections (4 p.m thick) on slides are deparaffinized, rehydrated, and then treated with 3% H202 to block endogenous peroxidase. They are placed in 0.1 M sodium citrate buffer (pH 6.0) and heated in a microwave oven. An EPOS rabbit antihuman Ki-67 antibody is applied as supplied (DAKO) it is ready to be used without any dilution. Color development is accomplished with metal-enhanced DAB for 15 min, followed by light counterstaining with hematoxylin. Quantification of Ki-67 antibody-labeled... 

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