Basic study of an agent for reinforcement of near-infrared fluorescence on tumor tissue

BACKGROUND AND AIMS

An indocyanine green derivative (ICG-sulfo-OSu) and agents for reinforcement of infrared fluorescence, which can be used as an infrared fluorescent labeling substance suitable for detection of microlesions by an IR fluorescence endoscope, have been developed. The study aims were to confirm the ability of a reinforcement agent, as well as imaging processing, to intensify fluorescence from the labeled antibody on immunohistochemical staining.

SUBJECTS AND METHODS

ICG-sulfo-OSu-labeled MUC1 antibody and an IR fluorescence imaging system were employed in the present study. Paraffin sections of gastric cancer were stained with anti-MUC1 antibody by the avidin-biotinylated peroxidase complex method. Among the positive specimens, three cases were used for IR imaging analysis. Octylglucoside was used as a reinforcement agent.

RESULTS

The incubation of paraffin sections with ICG-sulfo-OSu-labeled MUC1 antibody resulted in positive staining of the tumor sites by an IR fluorescence imaging system, and the intensity of fluorescence was increased depending on the concentration of octylglucoside and grade of imaging processing.

CONCLUSION

A reinforcement agent, and image processing, intensify a labeled antibody excitable by infrared fluorescence in tumor sections and can generate a strong enough fluorescent signal to detect small cancers when examined with an infrared fluorescence endoscope.

Detection of human gastric cancer in resected specimens using a novel infrared fluorescent anti-human carcinoembryonic antigen antibody with an infrared fluorescence endoscope in vitro

BACKGROUND AND STUDY AIMS

An indocyanine green derivative (ICG-sulfo-OSu) that can be used as an infrared fluorescent labeling substance suitable for detecting microlesions with an infrared fluorescence endoscope has been developed. The aims of the present study were to develop an infrared fluorescence endoscope and to demonstrate its usefulness in detecting cancerous tissue using an antibody coupled with ICG-sulfo-OSu.

MATERIALS AND METHODS

ICG-sulfo-OSu-labeled mouse anti-human carcinoembryonic antigen (CEA) antibody and an infrared fluorescence endoscope were used in this study. Biopsy specimens of gastric cancer were stained with anti-CEA antibody using the avidin-biotinylated peroxidase complex method. The positive specimens used for the infrared imaging analysis were freshly resected stomachs from three patients.

RESULTS

Treatment of freshly resected stomach specimens with ICG-sulfo-OSu-labeled-anti-CEA antibody complex resulted in positive staining of the tumor sites on infrared fluorescence endoscopy, and the infrared fluorescent images correlated well with the tumor sites.

CONCLUSIONS

An anti-CEA antibody with affinity for cancerous lesions and labeled with ICG-sulfo-OSu can therefore be imaged using this infrared fluorescence endoscope. Specific antibodies tagged with ICG-sulfo-OSu can label cancer cells and can generate a strong enough fluorescent signal to detect small cancers when examined with an infrared fluorescence endoscope.

Endoscopic sonography in the diagnosis of gallbladder wall lesions in patients with gallstones

PURPOSE

The purpose of this study was to evaluate the diagnostic accuracy of endoscopic sonography (EUS) in the detection of gallbladder wall lesions in patients with and without gallstones.

METHODS

We retrospectively reviewed the medical records, sonograms, and sonographic reports of 62 patients who underwent cholecystectomy for gallbladder wall lesions evaluated by EUS. We assessed the accuracy of EUS in diagnosing gallbladder wall lesions in the presence or absence of gallstones and on the basis of the size and number of stones and the size of the gallbladder wall lesions. We also evaluated the effect of acoustic shadowing. The EUS results were compared with the histopathologic results.

RESULTS

EUS correctly diagnosed the gallbladder wall lesions in 17 (71%) of 24 patients with gallstones and in 34 (89%) of 38 patients without gallstones. The diagnostic accuracy of EUS was 86% in patients with gallbladder wall lesions smaller than 20 mm and 79% in patients with gallbladder wall lesions 20 mm or larger. The diagnostic accuracy was 75% in patients with gallstones smaller than 5 mm and 67% in patients with stones 5 mm or larger. The accuracy was 67% in patients with 1-5 stones and 83% in patients with 6 or more stones. None of these differences was statistically significant. Acoustic shadowing did not affect the diagnostic accuracy of EUS.

CONCLUSIONS

The diagnostic accuracy of EUS for gallbladder wall lesions is not affected by the presence of gallstones. However, better diagnostic criteria must be established based on larger studies, and technical refinements of the equipment are needed to increase the accuracy of EUS in the diagnosis of gallbladder wall lesions.

Quantitative analysis of red color sign in the endoscopic evaluation of esophageal varices

BACKGROUND AND STUDY AIMS

Bleeding due to esophageal variceal rupture is associated with an extremely high mortality rate. Variceal bleeding is frequent in patients who have a red color sign on endoscopy. However, the red color sign is subjectively evaluated on the basis of color tone and the shape of the varices. To allow standardization and facilitate consensus, an objective method of assessing the red color sign is needed. In this study, a system was established for quantifying the red color sign during endoscopic evaluation.

PATIENTS AND METHODS

Between July 1995 and February 1997, 55 untreated patients with portal hypertension and esophageal varices identified on upper gastrointestinal endoscopy were enrolled in the study. Images obtained about 5 cm oral to the esophagogastric junction during endoscopy were stored on magnetic optical disks using an endoscopic image processor. The still images were transmitted to a computer and analyzed using computer software. The RGB components (R, red; G, green; B, blue) were measured at points showing flare consistent with the red color sign. The endoscopic assessment was based on the Japanese Research Society for Portal Hypertension's general rules for recording endoscopic findings in esophagogastric varices.

RESULTS

The ratio of the red color area to the variceal area increased with increasing red color grade. There were significant positive correlations between the R and G, and G and B components. This suggests that comparing the R components alone would allow assessment of the color differences in the red color area and in the varices. The R value was significantly higher in the red color area (115 +/- 20) than in the varices (57 +/- 19). An R value of 90 was found at the boundary between the two parts (P < 0.001).

CONCLUSIONS

The red color area can be automatically calculated and quantified using the analysis program. Improvements in data storage methods may allow real-time evaluation during endoscopy in the future.

Vital immunostaining of human gastric and colorectal cancers grafted into nude mice: a preclinical assessment of a potential adjunct to videoendoscopy

Videoendoscopy has not significantly advanced diagnostic accuracy beyond that attainable by conventional fiberscopy, with respect to microcarcinomas of the digestive tract. We suspected that after the labeling of these lesions with an agent detectable by videoendoscope, digital processing of the images could facilitate endoscopic diagnosis of microcarcinomas. We have developed a novel antibody labeled with an indocyanine green (ICG) derivative that is evident by videoendoscope. However, the binding of such an exogenous antibody in vivo to tumor surfaces has not been described. In this preliminary study, after transplanting human gastric cancer or colorectal cancer into nude mice, we successfully bound the tumors in vivo with an anti-MUC1 mucin antibody, as subsequently confirmed by the performing of immunohistochemistry with a secondary antibody. The antibody labeled with an ICG derivative may therefore be clinically useful in detecting gastrointestinal microcarcinoma by videoendoscopy.

Asymptomatic case of congenital absence of the gallbladder

Congenital absence of the gallbladder is rare among biliary abnormalities, and its preoperative diagnosis has been considered very difficult. We encountered a patient with congenital absence of the gallbladder and suggest a possible preoperative diagnosis of the abnormality, as well as reviewing the literature.