Goichi Togo

Single-balloon versus double-balloon endoscopy for achieving total enteroscopy: a randomized, controlled trial

BACKGROUND Balloon endoscopy has been accepted as an effective tool for examining the small intestine. Two types of balloon endoscopy, single and double, are commercially available. The difference in performance between these 2 types of balloon endoscopy has not yet been elucidated. OBJECTIVE To compare the yield of single-balloon endoscopy (SBE) and double-balloon endoscopy (DBE). DESIGN Single-center, randomized, controlled trial. SETTING University hospital in Tokyo, Japan. PATIENTS Patients with suspected small-bowel disease. INTERVENTIONS SBE and DBE. MAIN OUTCOME MEASUREMENTS Outcomes were the total enteroscopy rate, diagnostic yield, complication rate, and clinical outcomes. Analysis was done by intent to treat. RESULTS The study started in April 2008 and was terminated in April 2010 because of an obvious disadvantage for the SBE group. Thirty-eight patients were enrolled in the study; 18 patients were assigned to the SBE group and 20 to the DBE group. The total enteroscopy rate was 0% in the SBE group and 57.1% in the DBE group (P = .002). In terms of complications, the DBE group had 1 patient with Mallory-Weiss syndrome, and the SBE group had 1 patient with hyperamylasemia. There was no difference in the overall diagnosis rate between the SBE and DBE groups (61.1% vs 50.0%, P = .49). There was no difference in therapeutic outcome between the SBE and DBE groups (27.8% vs 35.0%, P = .63). LIMITATIONS Relatively small number of study patients. CONCLUSIONS Total enteroscopy is more easily performed with DBE than with SBE.

Rapid Detection of Mutations in the 23S rRNA Gene of Helicobacter pylori That Confers Resistance to Clarithromycin Treatment to the Bacterium

ABSTRACT We developed a new method capable of detecting point mutations in the 23S rRNA gene of Helicobacter pylori using a LightCycler. Our method can detect a mutation in this gene in less than 1 h and can process many samples at once, thereby contributing to the selection of patients suitable for clarithromycin-based therapy.

Frameshift mutations at mononucleotide repeats in RAD50 recombinational DNA repair gene in colorectal cancers with microsatellite instability.

To identify additional genes targeted for microsatellite instability (MSI), we search for human genes which contain mononucleotide repeats in their coding region, selected 7 genes (RAD50, DNA‐PKcs, FLASH, Apaf‐1, XPG, CtIP, and MLSN1), and analyzed frameshift mutations in them. Here we report that 60% (3 out of 5) of human colorectal cancer cell lines exhibiting a high frequency of MSI (MSI‐H) and 46% (6 out of 13) of MSI‐H primary colorectal tumors had mutations in the (A)9 repeat of RAD50 recombinational repair gene. In contrast, no frameshift mutations were found in any of the 5 MSI‐negative colorectal cancer cell lines, 8 colorectal tumors exhibiting a low frequency of MSI (MSI‐L), or 28 MSI‐negative colorectal tumors. No mutations were found in the mononucleotide repeats of 6 other genes, even in MSI‐H cancers. These results suggest that RAD50 frameshift mutations may play a role in the tumorigenesis of MSI‐H colorectal cancers.

Utility of single and double balloon endoscopy in patients with difficult colonoscopy: a randomized controlled trial.

AIM To compare the utility of single-balloon colonoscopy (SBC) or double-balloon colonoscopy (DBC) for difficult colonoscopies. METHODS Between August 2008 and June 2010, patients in whom total colonoscopy failed within 30 min of insertion were assigned randomly to undergo either SBC or DBC. No sedatives were used. After the endoscopy, all patients were asked to evaluate pain during the procedure on a 10-point analog scale (1 = no pain; 10 = worst imaginable pain) with a questionnaire. The study outcomes were the cecal intubation rate and time, endoscopic findings, complications, and pain score. RESULTS The SBC and DBC groups included 11 and 10 patients, respectively. All but one SBC patient achieved total colonoscopy successfully. The cecal intubation times were 18 min (range: 10-85 min) and 12.8 min (range: 9.5-42 min) in the SBC and DBC groups, respectively (P = 0.17). No difference was observed in the prevalence of colon polyps between the SBC and DBC groups (45% vs 30%, P = 0.66). SBC showed advanced colon cancer in the ascending colon, which was inaccessible using conventional colonoscopy. The respective pain scores were 5 (1-10) [median (range)] and 5 (1-6) in the SBC and DBC groups (P = 0.64). No complications were noted in any patient. CONCLUSION The utility of single- and double-balloon endoscopy for colonoscopy seems comparable in patients with incomplete colonoscopy using a conventional colonoscope.

Simple quantitative assay of alpha-fetoprotein mRNA in liver tissue using the real-time detection polymerase chain reaction assay - its application for clinical use.

Alpha-feto protein (AFP) mRNA levels increase in hepatocellular carcinoma (HCC) cells as compared with non-neoplastic tissue. Therefore, detection of AFP mRNA in blood nuclear cells is useful for the evaluation of treatment efficacy and prognosis of HCC. In this study, simple and reproducible methods were developed to quantify AFP mRNA using the real-time RT-PCR assay (Taq Man assay). By using in vitro synthesized AFP and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) RNA, the sensitivity and dynamic range of the RT-PCR assay were established. AFP mRNA in both HCC and non-neoplastic tissue, as well as in cell lines, were measured using this assay system. The expression of the AFP mRNA level was normalized using the GAPDH house keeping gene product as an endogenous reference. AFP and GAPDH mRNA can be quantified in the range of 10-10(8) copies when using this quantitative assay. Among HCC cell lines, Huh 7 and HepG2 cells, respectively, represented 1.5x10(6) and 6.0x10(5) AFP mRNA/10(6) GAPDH mRNA, in contrast to 6, 23 and 230 AFP mRNA/10(6) GAPDH mRNA for HLE, HLF and PLC/PRF/5 cells, respectively. Other cell lines derived from stomach, pancreas, and colon cancers have 10 AFP mRNA copies/10(6) GAPDH mRNA. In liver tissue from patients with chronic hepatitis, and the non-neoplastic portion of the liver from HCC patients, AFP mRNA distributes from 2.5x10(3) to 5.8x10(4)/10(6) GAPDH transcripts. In contrast, AFP mRNA in tumor cells were more than 100-fold higher than that found in corresponding non-neoplastic portions in two patients who had a high level of AFP in serum. The establishment of the TaqMan quantifying system for AFP mRNA may have important clinical implications.

Rapid detection of mutations in the BRAF gene using real-time polymerase chain reaction and melting curve analysis

The BRAF gene is mutated in 66% of melanomas and less frequently in various human cancers. More than 80% of these mutations are T to A transversions at nucleotide 1796 (T1796A), leading to a substitution of glutamic acid for valine at amino acid 599 (V599E). We established a new method for rapidly detecting V599E mutations using real-time polymerase chain reaction and melting curve analysis. Furthermore, we examined mutations in gastrointestinal cancer cell lines using this method. We found a mutation in 1 of 12 (8%) colorectal cancer cell lines, but no mutation was detected in 9 gastric cancer cell lines. These results suggest that the BRAF mutation is unlikely to be involved in gastric carcinogenesis.

SURVEILLANCE OF SMALL INTESTINAL ABNORMALITIES IN PATIENTS WITH HEPATOCELLULAR CARCINOMA: A PROSPECTIVE CAPSULE ENDOSCOPY STUDY

Background:  Patients with hepatocellular carcinoma (HCC) sometimes suffer from obscure gastrointestinal bleeding. Portal hypertension (PH), common in cirrhosis, induces esophagogastric varices. Because of the location, PH also may influence mucosal abnormalities in the small intestine. The objective of this study is to estimate the prevalence of small intestinal mucosal abnormalities in HCC patients using capsule endoscopy (CE).

Does Mutation of Transforming Growth Factor-β Type II Receptor Gene Play an Important Role in Colorectal Polyps?

Mutations in the transforming growthfactor-β type II receptor (RII) gene that remainuncorrected due to mutation and inactivation of mismatchrepair genes play an important role in hereditarynonpolyposis colorectal cancer (HNPCC) and in a subset ofsporadic colorectal cancers. Some colorectal cancersdevelop from colorectal polyps. To elucidate the role ofthe RII gene in the generation of colorectal polyps, we analyzed 137 colorectal polyps from 100patients for RII mutations and microsatelliteinstability (MSI). MSI was detected in three of 36polyps from 25 patients. For one of these three polyps,the mobilities of the PCR products between polyp and nonpolyptissues was different for only one microsatellitemarker, and for the other two polyps the mobilities weredifferent for more than two markers. These two polyps were obtained from one patient with ascendingcolon carcinoma and suspected HNPCC based on hisclinical profile and family history. An RII mutation wasdetected in only one of these two polyps. RII may play a minor role in sporadic colorectalpolyps. RII gene analysis in colorectal polyps may be auseful screening measure for potential HNPCCpatients.

Relationship Between Grade of Microsatellite Instability and Target Genes of Mismatch Repair Pathways in Sporadic Colorectal Carcinoma

Microsatellite instability (MSI) induces carcinoma through the alteration of target genes; TGF-β RII, BAX, IGFIIR, hMSH3, and hMSH6. The grade of MSI is classified into two categories according to the number of positive microsatellite markers; MSI-H and MSI-L. To elucidate the relationship between the propriety of grading MSI, target genes and clinical features of sporadic colorectal cancers, MSI and frameshift mutation of target genes were examined in 132 colorectal cancer patients. Fourteen and 12 cases showed MSI-H and MSI-L, respectively. Of the 14 MSI-H cases, 13 cases showed alteration of target genes. However, of the 12 MSI-L cases, only one case showed alteration of one target gene. Furthermore, all 14 MSI-H patients had cancers of the right colon and were typically older in age than the MSI-negative patients. These results imply a strong relationship between MSI-H and carcinogenesis by the frameshift mutation of target genes.