title: Standardization of interphase Ag-NOR measurement by means of an automated image analysis system using lymphocytes as an internal control.
abstract: Using an automated image analysis system, we have developed a procedure for standardizing the measurement of silver-stained proteins of the nucleolar organizer regions (NORs) in cancer cells, irrespective of the fixative employed and the time of the staining reaction. We observed that the area of Ag-NOR proteins from the same tumour was smaller in samples fixed with formalin-containing solutions, buffered formalin, and Bouin liquid, compared with those fixed with absolute ethanol and 'methcarn' solution (1.77 +/- 0.26micron 2 and 2.36 +/- 0.35 micron2 versus 3.34 +/- 0.54 micron2 and 3.72 +/- 0.61 micron2). Increased values of the Ag-NOR area were also observed after lengthening the silver staining reaction. However, in both cases no difference was observed in the ratio between Ag-NOR area of cancer cells and that of the lymphocytes infiltrating the stroma. The value of the ratio, which is called the 'Ag-NOR index', was in fact very similar, for the same cancer, after employing different fixatives or staining times. The use of lymphocyte Ag-NOR area as an internal control for the standardization of Ag-NOR evaluation in cancer tissues was made possible by the fact that lymphocyte Ag-NOR area is almost constant in human tumours independent of sex and age.
authors.affiliation: Dipartimento di Patologia Sperimentale, Università di Bologna, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Derenzini
authors.forename: D
authors.initials: D
authors.lastname: Trerè
mesh_terms: D000328:Adult; D003584:Cytological Techniques / Q000592:standards*; D005260:Female; D005404:Fixatives; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D007399:Interphase; D008214:Lymphocytes / Q000648:ultrastructure; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000648:ultrastructure*; D009697:Nucleolus Organizer Region / Q000648:ultrastructure*; D016622:Silver Staining; D013997:Time Factors
chemical_list: D005404:Fixatives