Naoki Muguruma

Synthesis and reactivities of 3-indocyanine-green-acyl-1,3-thiazolidine-2-thione (ICG-ATT) as a new near-infrared fluorescent-labeling reagent

A new near-infrared fluorescent-labeling reagent (ICG-ATT) bearing the 3-acyl-1,3-thiazolidine-2-thione (ATT) moiety with the chemoselective acylation feature and the dye moiety of indocyanine green (ICG) has been developed. Synthesis and reactivities of the ICG-ATT are described.

Development of fluorescence-emitting antibody labeling substance by near-infrared ray excitation

Abstract Indocyanine green succinimidyl esters, near-infrared labeling dyes, were synthesized. These reagents were indocyanine green derivatives possesing N-hydroxysuccinimidyl groups capable of reacting with proteins. The absorption maximum of indocyanine green-labeled human IgG was 785 nm, and its fluorescent excitation and emission maxima were 768 nm and 807 nm, respectively.

Antibodies labeled with fluorescence-agent excitable by infrared rays

Abstract: Endoscopy is not significantly better than fiberscopy for the diagnosis of minute cancers of the digestive tract. However, labeling of these lesions with an agent that can be detected videoendoscopically, with subsequent computer processing of the electronic signals, should facilitate endoscopic diagnosis of microlesions. We developed an antibody labeled with an indocyanine green(ICG) derivative that has a specific fluorescence emission at 807 nm upon excitation at 768 nm. The physiochemical characteristics of this labeled antibody resemble those of ICG. The activity of the antibody is suitable for immunohistochemical staining, and the antibody fluoresces under infrared ray excitation. This antibody should prove useful for performing vital immunostaining for infrared endoscopy.

Relationship among gastric motility, autonomic activity, and portal hemodynamics in patients with liver cirrhosis

We examined the effects of the autonomic nervous function and the volume of portal blood flow to clarify the mechanism of the abnormal gastric motility in patients with liver cirrhosis.

Basic studies on a labeled anti-mucin antibody detectable by infrared-fluorescence endoscopy

Background. We developed a fluorescent dye, indocyanine green (ICG)-sulfo-OSu, which was excited by infrared rays and conjugated to various antibodies. We attempted to clarify the staining patterns of anti-sulfomucin and anti-MUC1 antibodies in gastrointestinal cancer. We then evaluated the potential of the dye as a fluorescent label for antibodies specific to cancer, to be used as a diagnostic method for microcancer, with infrared fluorescence endoscopy. Methods. Paraffin sections of samples collected from 10 patients with esophageal cancer, 30 patients with gastric cancer, and 20 patients with colorectal cancer were immunohistologically stained using an anti-sulfomucin antibody and an anti-MUC1 antibody, and the staining patterns were examined. If a section had a high staining intensity, it was reacted with the ICG-suflo-OSu-labeled antibody and evaluated with infrared fluorescence imaging. Results. The staining patterns with the antibodies varied depending on the organs and the histological types and depth of the cancers, but the staining was generally good and the staining on the mucosal surface of cancer tissues was retained. Good images of cancer cells could be obtained by infrared fluorescence observation using the ICG-sulfo-OSu-labeled anti-MUC1 antibody. Conclusions. The anti-MUC1 antibody stained gastrointestinal cancer cells well, and nearly specific infrared fluorescence in cancer tissues was observed using the labeled anti-MUC1 antibody. The ICG-sulfo-OSu-labeled anti-MUC1 antibody has possible usefulness for the screening of cancer via infrared fluorescence endoscopy.

Colorectal xanthomas with polypoid lesion: Report of 25 cases

Little attention has been paid to colorectal xanthoma. To clarify the clinical and pathological features of colorectal xanthoma, we report 28 colorectal xanthomas biopsied from 25 patients. All were composed of typical xanthoma cells and showed polypoid configuration. Median age of the patients was 64 years and there were 15 men and 10 women. Diabetes mellitus, constipation, and hyperlipidemia were found in two, one, and seven patients, respectively. Seventeen (60.7%) of the 28 polyps were located in the sigmoid colon and the remaining 11 in the rectum. Twenty‐three polyps (82.1%) were sessile. Twelve (60.0%) of twenty polyps that were recorded were reddish in color. Only two polyps revealed a yellowish tone. Microscopically, foamy cells were present in the lamina propria, but the submucosa did not contain foamy cells. Immunohistochemically, the foamy cells invariably expressed extensive positivity for CD68. The colonic glands showed a deformity in the case with moderate to intense density of the foamy cells. The surface epithelium showed a hyperplastic change in 22 (78.6%) xanthomas. The colonic glands in four xanthomas were also associated with hyperplastic changes. The basement membrane of the surface epithelium was often thickened. Cell debris and proliferation of the capillaries were observed just below the surface epithelium in 19 (67.9%) and 22 (78.6%) xanthomas, respectively. Previous mucosal minute injury was suggested as the pathogenesis of colorectal xanthomas. Colorectal xanthomas were not identical to gastric and esophageal xanthoma, endoscopically or microscopically. We prefer the term “xanthomatous polyp” rather than xanthoma in the colorectal region. They may be regarded as a novel type of colorectal non‐neoplastic polyp.

Ultrasonographic assessment of gastric motility in diabetic gastroparesis before and after attaining glycemic control.

BackgroundGlycemic control is important for maintaining gastric motility in diabetic patients, but gastric motility has not yet been studied ultrasonographically in relation to glycemic control.MethodsWe made such observations before and after establishing glycemic control in diabetic patients with gastroparesis. We studied 30 diabetic patients with upper abdominal digestive symptoms who were hospitalized for correction of poor blood sugar control and who underwent upper digestive tract endoscopy to rule out structural causes such as gastric/duodenal lesions. Gastric motility was evaluated by transabdominal ultrasonography, using a test meal, before and after attainment of glycemic control (within 3 days after admission and 3 days before discharge). Also, upper abdominal digestive symptoms present on admission and at discharge were compared.ResultsAfter glycemic control was established, contractions of the antral region were more frequent than before the attainment of control (8.93 ± 1.17/3 min vs 7.63 ± 2.22/3 min, respectively; P < 0.001). Glycemic control also significantly improved gastric emptying (before glycemic control, 49.2 ± 14.8%; after, 67.1 ± 11.5%; P < 0.001). This was also true for the motility index, concerning antral gastric contractility (before control, 2.97 ± 1.57; after, 3.75 ± 1.09; P < 0.05). Upper abdominal symptom scores were also significantly lower after attainment of control than before (0.47 ± 0.78 vs 3.17 ± 2.00, respectively; P < 0.001).ConclusionsThese findings suggest that attaining glycemic control improves gastric motility and attainments upper abdominal symptoms in diabetic patients with gastroparesis.

Mucosectom2-short blade for safe and efficient endoscopic submucosal dissection of colorectal tumors.

BACKGROUND AND STUDY AIMS Endoscopic submucosal dissection (ESD) in the colon has rapidly come into widespread use. However, as complications such as bleeding and perforation often occur, and the procedure time is longer for ESD than for endoscopic mucosal resection (EMR), development of safer and more reliable devices are required especially for colorectal ESD. We report on a new device, the Mucosectom2-short blade (M2-SB) for colorectal ESD and describe its safety and efficacy. PATIENTS AND METHODS The study included 30 patients with lesions diagnosed as colorectal tumor: a nongranular-type laterally spreading tumor (LST) larger than 20 mm or a granular-type LST larger than 30 mm, or lesions that were evaluated as being difficult to remove even by piecemeal EMR. RESULTS All lesions were resected en bloc using this new device, with free lateral and vertical margins. The procedure time was 61 minutes and there was no bleeding or perforation related to the procedure. CONCLUSION The M2-SB seems to be a safe and efficient tool for colorectal ESD.

Clinical benefit of high-sensitivity KRAS mutation testing in metastatic colorectal cancer treated with anti-EGFR antibody therapy.

Objective: We compared high-sensitivity KRAS mutation testing with direct sequencing for predicting the efficacy of antiepidermal growth factor receptor antibodies in patients with metastatic colorectal cancer (mCRC). Methods: We analyzed the KRAS status in 61 tumors from cetuximab-treated mCRC patients by both direct sequencing and a high-sensitivity method: 2-step PCR restriction fragmentation length polymorphism (RFLP). Therapeutic effects in each mutational status were evaluated. Results: The incidences of KRAS mutations determined by direct sequencing and 2-step PCR RFLP were 34.4 and 52.5%, respectively (p = 0.02). Patients were categorized into 3 groups [W/W, wild-type by both methods (n = 29); W/M, wild-type by direct sequencing, detected mutation by 2-step PCR RFLP (n = 11); M/M, mutant-type by both methods (n = 21)]. The response rate for cetuximab in the W/M group (0%) was the same as that in the M/M group, and was significantly lower than in the W/W group (41.4%) (p < 0.001). Progression-free survival in the W/M group (11.0 weeks) was similar to that in the M/M group (8.0 weeks), and was significantly shorter than in the W/W group (18.0 weeks) (p < 0.002). Conclusion: High-sensitivity KRAS mutation testing is useful for selecting true responders to cetuximab.

A new infrared fluorescent-labeling agent and labeled antibody for diagnosing microcancers.

PURPOSE We have developed infrared fluorescent labeling agents and infrared-ray fluorescence endoscopes to establish a novel diagnostic technique. Since the fluorescence intensity of the initial labeled antibody (ICG-sulfo-OSu-labeled antibody) was not sufficient for practical use, we synthesized indocyanine green acylthiazolidinethione (ICG-ATT), which was expected to label various target molecules having amino groups efficiently. MATERIALS AND METHODS To confirm imaging of infrared fluorescence intensity of ICG-ATT- and ICG-sulfo-OSu-labeled anti-MUC1 antibodies, cotton thread was soaked in various concentrations of the antibody solution in 0.1M PBS, and observed under the epi-illumination infrared fluorescence microscope. Localization and the intensity of infrared fluorescence and DAB coloring was compared in paraffin sections of human gastric mucosa. RESULTS In the study of cotton threads, both labeled antibodies showed relatively clear infrared fluorescence, and significant difference was not observed between the two antibodies. ICG-ATT-labeled anti-MUC1 antibody produced stronger staining than that by ICG-sulfo-OSu-labeled antibody. Localization pattern of infrared fluorescent staining was in good agreement with that by the conventional method with oxidized DAB staining. CONCLUSION ICG-ATT is useful as a fluorescent-labeling agent for diagnosis of microcancers by infrared fluorescence endoscopes.