Frozen Section Immunohistochemistry of

Tissue specimens are snap-frozen at -60°C in an isopentane freezing bath (Neslab, Portsmouth, NH) (Resnick et al., 1995). Sections (5 pan thick) are cut on a cryostat, 

Other putative effects of estrogens include preservation of autoregulatory function, an antioxidant effect, reduction of A(i production and neurotoxicity, reduced excitotoxicity, increased expression of antiapoptotic factor bcl-2, and activation of mitogen-activated protein kinase pathways. Also, there is overwhelming data indicating that estrogens enhance survival of neurons both in vitro and in vivo (Green and Simpkins, 2000). 

Estrogens are synthesized not only in females but also in males. The synthesis of this hormone by cytochrome P450 aromatase in Leydig and Sertoli cells of the testis is well known (Carreau et al., 1999). This cytochrome is also found in the brain, where estrogen is important for imprinting male behavior (Beyer, 1999). There is clear evidence that the role of ER in males is associated with the maintenance of fluid reabsorption in the head of the epididymis (Hess et al., 1997). The loss of ER function in males interferes with the resorp-tive function of efferent ductules, a function that is essential for fertility (Hess, 2000). 

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The immunohistochemistry of ERs has been exhaustively compared with the DCC assay. Review of the literature indicates -85% agreement between these two methods (Allred, 1999). This is true when immunohistochemistry is restricted to fresh-frozen sections. Immunohistochemistry of frozen sections compared with paraffin sections is a more specific test to detect ER-positive tumors with very low tumor cellularity the DCC assay gives false-negative results for such tumors. A number of publications have also reported good agreement between the DCC assay and immunohistochemistry of paraffin-embedded... 

F(ab) fragments of both conjugated and unconjugated antibodies are preferred in frozen section immunohistochemistry of lymphoid tissues in order to avoid nonspecific binding of antibodies through their FC fragments to Fc receptors (present on B lymphocytes) (17). 

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