Limits...
In Vivo Detection of Rat Colorectal Cancers by using a Dual-Wavelength Excitation Method.

Miyawaki K, Harada Y, Wakabayashi N, Imaizumi K, Koizumi N, Nakano K, Yamaoka Y, Dai P, Itoh Y, Takamatsu T - Acta Histochem Cytochem (2014)

Bottom Line: After autofluorescence images at 470 nm irradiated with dual-wavelength excitation at 365 nm (F365 ex) and 405 nm (F405 ex) were acquired, ratio images were produced by dividing F365 ex by F405 ex: The excitation-emission wavelength pairs in F365 ex and F405 ex were adjusted for acquisition of NADH fluorescence and reference fluorescence.The signal values in F365 ex/F405 ex ratio images were less mutually related with the hemoglobin concentration index.Small adenocarcinomas (less than 4 mm) could be detected on F365 ex/F405 ex ratio images.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology and Cell Regulation, Kyoto Prefectural University of Medicine Graduate School of Medical Science ; Department of Gastroenterology and Hepatology, Kyoto Prefectural University of Medicine Graduate School of Medical Science.

ABSTRACT
Hypoxia is a characteristic feature of solid neoplasms, and insufficient oxygen supply increases cellular nicotinamide adenine dinucleotide (NADH) fluorescence, which is a main component of autofluorescence of the colorectal mucosa. We investigated whether a dual-wavelength excitation method which is optimized for sensing mucosal NADH fluorescence could be applicable to the detection of rat colorectal cancers in vivo. Rat colorectal adenocarcinomas were studied by using fluorescence stereomicroscopy. After autofluorescence images at 470 nm irradiated with dual-wavelength excitation at 365 nm (F365 ex) and 405 nm (F405 ex) were acquired, ratio images were produced by dividing F365 ex by F405 ex: The excitation-emission wavelength pairs in F365 ex and F405 ex were adjusted for acquisition of NADH fluorescence and reference fluorescence. Based on observations from the luminal surface in vivo, F365 ex/F405 ex ratio images indicated a 1.57-fold higher signal value in the cancers than in the surrounding normal mucosa. The signal values in F365 ex/F405 ex ratio images were less mutually related with the hemoglobin concentration index. Small adenocarcinomas (less than 4 mm) could be detected on F365 ex/F405 ex ratio images. The results showed that NADH fluorescence measurement with little interference from tissue hemoglobin is efficient for visualizing rat colorectal cancers in vivo, suggesting that the dual-wavelength excitation method has potential for label-free endoscopic detection of diminutive colorectal neoplasms.

No MeSH data available.


Related in: MedlinePlus

Dual-wavelength excitation method can clearly distinguish cancerous mucosa from non-cancerous mucosa in sliced colorectal cross-sections. Representative images of a sliced cross-section of colorectal adenocarcinoma are shown (A–D). H&E-stained image (A) revealed histology of adenocarcinoma. Autofluorescence images [(B) (F365ex: fluorescence at 470 nm with 365-nm excitation) and (C) (F405ex: fluorescence at 470 nm with 405-nm excitation)] and a pseudocolor ratio image (D) acquired by dividing F365ex by F405ex, are presented. Different colors in the pseudocolor ratio image (D) indicate different ratios as shown by the inserted color bars. Scatter plots for ratios between signal intensities in tumorous regions and normal regions (T/N ratios) in F365ex, F405ex, and F365ex/F405ex are shown in E. Bar=1 mm (D). The short horizontal lines in E show average values.
© Copyright Policy - open-access
Related In: Results  -  Collection


getmorefigures.php?uid=PMC4387246&req=5

Figure 1: Dual-wavelength excitation method can clearly distinguish cancerous mucosa from non-cancerous mucosa in sliced colorectal cross-sections. Representative images of a sliced cross-section of colorectal adenocarcinoma are shown (A–D). H&E-stained image (A) revealed histology of adenocarcinoma. Autofluorescence images [(B) (F365ex: fluorescence at 470 nm with 365-nm excitation) and (C) (F405ex: fluorescence at 470 nm with 405-nm excitation)] and a pseudocolor ratio image (D) acquired by dividing F365ex by F405ex, are presented. Different colors in the pseudocolor ratio image (D) indicate different ratios as shown by the inserted color bars. Scatter plots for ratios between signal intensities in tumorous regions and normal regions (T/N ratios) in F365ex, F405ex, and F365ex/F405ex are shown in E. Bar=1 mm (D). The short horizontal lines in E show average values.

Mentions: Firstly, autofluorescence from the mucosal layer was observed in cross-sections of rat colorectal specimens (n=10: 10 cross-sections from 10 tumor tissues with surrounding non-tumor tissues) under the stereomicroscope. Stereomicroscopic and histologic images in a representative cross-section of a colorectal adenocarcinoma are shown in Figure 1A–D. In F365ex and F405ex, it is difficult to identify obviously tumorous mucosa on the basis of fluorescence intensity, because the differences of fluorescence intensity between tumorous mucosa and normal mucosa are small (Fig. 1B and C). However, the ratio images of F365ex/F405ex showed tumorous lesions in accordance with the histological picture, as shown in Figure 1A and 1D. To quantitatively analyze the fluorescence of tumorous and normal mucosa on cross-sectional observation, we examined the T/N ratios in F365ex, F405ex, and F365ex/F405ex images (Fig. 1E). The average T/N ratio in F365ex was more than 1.0 (1.40±0.073, p<0.01), and that in F405ex was less than 1.0 (0.81±0.13, p<0.01). There were still a few cases observed in which lesions were difficult to differentiate from normal areas owing to the small difference between the T/N ratios and 1.0 in the case of F405ex. The average T/N ratio in F365ex/F405ex demonstrated apparent increase (1.55±0.12, p<0.001), and all of the analyzed adenocarcinomas could be detected clearly using T/N ratio in F365ex/F405ex.


In Vivo Detection of Rat Colorectal Cancers by using a Dual-Wavelength Excitation Method.

Miyawaki K, Harada Y, Wakabayashi N, Imaizumi K, Koizumi N, Nakano K, Yamaoka Y, Dai P, Itoh Y, Takamatsu T - Acta Histochem Cytochem (2014)

Dual-wavelength excitation method can clearly distinguish cancerous mucosa from non-cancerous mucosa in sliced colorectal cross-sections. Representative images of a sliced cross-section of colorectal adenocarcinoma are shown (A–D). H&E-stained image (A) revealed histology of adenocarcinoma. Autofluorescence images [(B) (F365ex: fluorescence at 470 nm with 365-nm excitation) and (C) (F405ex: fluorescence at 470 nm with 405-nm excitation)] and a pseudocolor ratio image (D) acquired by dividing F365ex by F405ex, are presented. Different colors in the pseudocolor ratio image (D) indicate different ratios as shown by the inserted color bars. Scatter plots for ratios between signal intensities in tumorous regions and normal regions (T/N ratios) in F365ex, F405ex, and F365ex/F405ex are shown in E. Bar=1 mm (D). The short horizontal lines in E show average values.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4387246&req=5

Figure 1: Dual-wavelength excitation method can clearly distinguish cancerous mucosa from non-cancerous mucosa in sliced colorectal cross-sections. Representative images of a sliced cross-section of colorectal adenocarcinoma are shown (A–D). H&E-stained image (A) revealed histology of adenocarcinoma. Autofluorescence images [(B) (F365ex: fluorescence at 470 nm with 365-nm excitation) and (C) (F405ex: fluorescence at 470 nm with 405-nm excitation)] and a pseudocolor ratio image (D) acquired by dividing F365ex by F405ex, are presented. Different colors in the pseudocolor ratio image (D) indicate different ratios as shown by the inserted color bars. Scatter plots for ratios between signal intensities in tumorous regions and normal regions (T/N ratios) in F365ex, F405ex, and F365ex/F405ex are shown in E. Bar=1 mm (D). The short horizontal lines in E show average values.
Mentions: Firstly, autofluorescence from the mucosal layer was observed in cross-sections of rat colorectal specimens (n=10: 10 cross-sections from 10 tumor tissues with surrounding non-tumor tissues) under the stereomicroscope. Stereomicroscopic and histologic images in a representative cross-section of a colorectal adenocarcinoma are shown in Figure 1A–D. In F365ex and F405ex, it is difficult to identify obviously tumorous mucosa on the basis of fluorescence intensity, because the differences of fluorescence intensity between tumorous mucosa and normal mucosa are small (Fig. 1B and C). However, the ratio images of F365ex/F405ex showed tumorous lesions in accordance with the histological picture, as shown in Figure 1A and 1D. To quantitatively analyze the fluorescence of tumorous and normal mucosa on cross-sectional observation, we examined the T/N ratios in F365ex, F405ex, and F365ex/F405ex images (Fig. 1E). The average T/N ratio in F365ex was more than 1.0 (1.40±0.073, p<0.01), and that in F405ex was less than 1.0 (0.81±0.13, p<0.01). There were still a few cases observed in which lesions were difficult to differentiate from normal areas owing to the small difference between the T/N ratios and 1.0 in the case of F405ex. The average T/N ratio in F365ex/F405ex demonstrated apparent increase (1.55±0.12, p<0.001), and all of the analyzed adenocarcinomas could be detected clearly using T/N ratio in F365ex/F405ex.

Bottom Line: After autofluorescence images at 470 nm irradiated with dual-wavelength excitation at 365 nm (F365 ex) and 405 nm (F405 ex) were acquired, ratio images were produced by dividing F365 ex by F405 ex: The excitation-emission wavelength pairs in F365 ex and F405 ex were adjusted for acquisition of NADH fluorescence and reference fluorescence.The signal values in F365 ex/F405 ex ratio images were less mutually related with the hemoglobin concentration index.Small adenocarcinomas (less than 4 mm) could be detected on F365 ex/F405 ex ratio images.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathology and Cell Regulation, Kyoto Prefectural University of Medicine Graduate School of Medical Science ; Department of Gastroenterology and Hepatology, Kyoto Prefectural University of Medicine Graduate School of Medical Science.

ABSTRACT
Hypoxia is a characteristic feature of solid neoplasms, and insufficient oxygen supply increases cellular nicotinamide adenine dinucleotide (NADH) fluorescence, which is a main component of autofluorescence of the colorectal mucosa. We investigated whether a dual-wavelength excitation method which is optimized for sensing mucosal NADH fluorescence could be applicable to the detection of rat colorectal cancers in vivo. Rat colorectal adenocarcinomas were studied by using fluorescence stereomicroscopy. After autofluorescence images at 470 nm irradiated with dual-wavelength excitation at 365 nm (F365 ex) and 405 nm (F405 ex) were acquired, ratio images were produced by dividing F365 ex by F405 ex: The excitation-emission wavelength pairs in F365 ex and F405 ex were adjusted for acquisition of NADH fluorescence and reference fluorescence. Based on observations from the luminal surface in vivo, F365 ex/F405 ex ratio images indicated a 1.57-fold higher signal value in the cancers than in the surrounding normal mucosa. The signal values in F365 ex/F405 ex ratio images were less mutually related with the hemoglobin concentration index. Small adenocarcinomas (less than 4 mm) could be detected on F365 ex/F405 ex ratio images. The results showed that NADH fluorescence measurement with little interference from tissue hemoglobin is efficient for visualizing rat colorectal cancers in vivo, suggesting that the dual-wavelength excitation method has potential for label-free endoscopic detection of diminutive colorectal neoplasms.

No MeSH data available.


Related in: MedlinePlus