title: Nucleolar organizer regions as markers of incipient cellular alterations in squamous epithelium.
abstract: Transcriptionally active nucleolar organizer regions identified by silver staining (AgNOR) vary in number with cellular activity and/or malignant transformation and have been used as a diagnostic tool. A morphometric study of AgNORs was performed in an experimental model of irradiated squamous epithelium (Wistar rat sole skin) 4, 8, and 14 hours and 1, 2, 5, and 7 days post-irradiation with 50 Gy of x-rays. A statistically significant and progressive rise in AgNOR average volume of up to 238% and reduction in AgNOR number/nucleus of up to 40% were detected as a function of post-irradiation time. A statistically significant 46% increase in AgNOR volume was detected as early as 8 h post-irradiation, when no histological changes were observable in routine preparations. These results suggest that AgNORs may be useful as a quantitative marker of incipient changes in cellular activity and caution against the indiscriminate use of AgNORs in the follow-up of lesions which may have been exposed to radiotherapy. Furthermore, this study suggests the possibility of using AgNORs as a sensitive biological dosimeter in cases of uncontrolled exposure to radiation.
authors.affiliation: Department of Radiobiology, National Atomic Energy Commission, Buenos Aires, Argentina.
authors.forename: A E
authors.initials: AE
authors.lastname: Schwint
authors.forename: E
authors.initials: E
authors.lastname: Gomez
authors.forename: M E
authors.initials: ME
authors.lastname: Itoiz
authors.forename: R L
authors.initials: RL
authors.lastname: Cabrini
mesh_terms: D000818:Animals; D014408:Biomarkers, Tumor; D002471:Cell Transformation, Neoplastic / Q000648:ultrastructure*; D004848:Epithelium / Q000528:radiation effects; D009381:Neoplasms, Radiation-Induced / Q000648:ultrastructure*; D009697:Nucleolus Organizer Region / Q000528:radiation effects* / Q000648:ultrastructure*; D051381:Rats; D017208:Rats, Wistar; D016622:Silver Staining
chemical_list: D014408:Biomarkers, Tumor