紫外線膀胱鏡による膀胱腫瘍の診断に関する研究 -- とくに発色螢光色調の由来について --

Abstract

Acridine orange (AO) is a fiuorescent dye which has been widely used in a staining method of exfoliative cytology. This basic dye has strong affinity for nucleic acid in fixed cells as well as in living cells. The authors have already reported on fluorescence cystoscopy for early detection of cancer of the urinary bladder in which living epithelium of the urinary bladder was stained with AO. Normal intact epithelium showed green fluorescence and injured epithelium showed red fluorescence. Malignant epithelium of the bladder showed characteristic yellow fluorescence. The reason for this phenomenon has not been clear up to the present. Several reports have been published concerning the mechanism of emission of green, red and yellow fluorescence in various epitheliums vitally stained with AO. These reports were taken into consideration in the present investigation. The interaction between intracellular nucleic acids and AO was studied based on fluoromicroscopy of fresh cells and non-fixed frozen sections obtained from vitally stained portio vaginalis and urinary bladder. The results obtained are as follows: 1) Metachromatic shift occurs in AO solution as the concentration of AO increases. 2) Green fluorescence of normal intact epithelium is found to be due to the orthochromatic green fluorescence of the epithelial cells. It is supposed that this is due to the fact that nucleic acid-AO complex is formed mainly as the monomeric binding of AO to DNA. 3) The red fluorescence which injured epithelium shows is metachromatic red fluorescence of the cytoplasm. It is supposed that this is due to the fact that nucleic acid-AO complex is mainly formed as the dimeric or polymeric binding of AO to RNA. 4) The yellow fluorescence which malignant epithelium shows is metachromatic yellow fluorescence of the cells, especially of increased nuclei. It is supposed that this is due to the fact that nucleic acid-AO complex is formed as the monomeric and dimeric binding of AO to DNA and RNA. Although studies on the mechanism of emission of yellow fluorescence in malignancy are still being carried on, the authors recommend the fluorescence cystoscopy as a useful new procedure for early detection of cancer of the urinary bladder.