Norio Isoda

A novel method of endoscopic mucosal resection using sodium hyaluronate.

BACKGROUND Saline-assisted endoscopic mucosal resection is an established therapeutic method. However, it is sometimes difficult to maintain a desired level of tissue elevation after injection of saline. Therefore we decided to use a mucinous substance such as sodium hyaluronate instead of saline. METHODS Two resected porcine stomachs and five dogs were used for the study. The elevations, made by submucosal injections of sodium hyaluronate, were compared with those produced with normal saline. Sodium hyaluronate-assisted mucosal resections were compared with the saline-assisted resections. RESULTS Mucosal elevations created by submucosal injections of sodium hyaluronate remained for a longer time with a clearer margin compared to those made by saline injection. Endoscopic mucosal resections were performed safely with the assistance of sodium hyaluronate. CONCLUSIONS Use of sodium hyaluronate instead of saline for endoscopic mucosal resection could make the procedure easier and more reliable.

Development of Gastric Carcinoma from Intestinal Metaplasia in Cdx2-transgenic Mice

In the progression of chronic gastritis, gastric mucosal cells deviate from the normal pathway of gastric differentiation to an intestinal phenotype. Many epidemiologic studies have found an association between the formation of intestinal metaplasia and the development of gastric carcinoma. However, there is no direct evidence that shows intestinal metaplasia is a precursor lesion of gastric carcinoma, to date. We periodically examined the intestinal metaplastic mucosa of Cdx2-transgenic mice we have previously generated. Gastric polyps developed from intestinal metaplastic mucosa in all stomachs of Cdx2-transgenic mice examined. These gastric polyps consisted of intestinal-type adenocarcinoma that invaded the submucosa and muscularis propria and occasionally spread into the subserosa. p53 and APC gene mutations were recognized in the adenocarcinomas. The participation of APC and p53 gene mutations in gastric carcinogenesis from the intestinal metaplasia was verified by the Cdx2-transgenic mice, carrying ApcMin mutation or p53 deficiency, that developed gastric polyps much earlier than Cdx2 alone. We successfully showed that long-term intestinal metaplasia induces invasive gastric carcinoma. These results indicate that intestinal metaplasia itself plays a significant role in the genesis and progression of gastric carcinoma.

Identification of two distinct genotypes of hepatitis E virus in a Japanese patient with acute hepatitis who had not travelled abroad

Two distinct hepatitis E virus (HEV) isolates, designated HE-JI3 and HE-JI4, were identified in a single patient with acute hepatitis in Japan, who had not travelled abroad. The HEV load of HE-JI3 at admission was 10(2) copies/ml, but that of HE-JI4 was tenfold higher at 10(3) copies/ml. The viraemia of HE-JI4 persisted for up to 16 days from admission, whereas HE-JI3 disappeared at 9 days after admission. The entire nucleotide sequence of the HE-JI4 isolate and partial nucleotide sequences of open reading frames (ORFs) 1 and 2 of the HE-JI3 isolate were determined. The full-length nucleotide sequence of HE-JI4 consisted of 7171 nucleotides excluding the poly(A) tail and contained ORF1 encoding 1684 amino acids, ORF2 encoding 671 amino acids and ORF3 encoding 114 amino acids. Sequence and phylogenetic analyses of the HEV genomes indicated that HE-JI4 was most closely related to an HEV isolate (T1) of genotype IV with the same strategy for translation of ORF2 and ORF3, but which differed from it by 16.5% over the entire genome. The HE-JI3 isolate showed the highest nucleotide identity (88.6-95.1%) to the genotype III HEVs, having higher identity to human and swine HEV isolates from the United States (US1, US2 and swUS1) than to those reported thus far from Japan (JRA1 and swJ570). The two co-infecting strains of HE-JI3 and HE-JI4 identified from the single patient shared only 80.1% nucleotide identity. These results indicate that multiple genotypes of HEV co-circulate in Japan, and that genotype IV comprises a remarkably heterogeneous group of HEVs.

Hepatitis E Virus (HEV) Strains in Serum Samples Can Replicate Efficiently in Cultured Cells Despite the Coexistence of HEV Antibodies: Characterization of HEV Virions in Blood Circulation

ABSTRACT We recently developed a cell culture system for hepatitis E virus (HEV) in PLC/PRF/5 and A549 cells, using fecal specimens from HEV-infected patients. Since transfusion-associated hepatitis E has been reported, we examined PLC/PRF/5 and A549 cells for the ability to support replication of HEV in various serum samples obtained from 23 patients with genotype 1, 3, or 4 HEV. HEV progenies emerged in culture media of PLC/PRF/5 cells, regardless of the coexistence of HEV antibodies in serum but dependent on the load of HEV inoculated (31% at 2.0 × 104 copies per well and 100% at ≥3.5 × 104 copies per well), and were successfully passaged in A549 cells. HEV particles in serum, with or without HEV antibodies, banded at a sucrose density of 1.15 to 1.16 g/ml, which was markedly lower than that for HEV particles in feces, at 1.27 to 1.28 g/ml, and were nonneutralizable by immune sera in this cell culture system. An immuno-capture PCR assay of HEV virions treated with or without detergent indicated that HEV particles in serum are associated with lipids and HEV ORF3 protein, similar to those in culture supernatant. By immunoprecipitation, it was found that >90% of HEV particles in the circulation exist as free virions not complexed with immunoglobulins, despite the coexistence of HEV antibodies. These results suggest that our in vitro cell culture system can be used for propagation of a wide variety of HEV strains in sera from various infected patients, allowing extended studies on viral replication specific to different HEV strains.

Infection of a Japanese Patient by Genotype 4 Hepatitis E Virus While Traveling in Vietnam

ABSTRACT Cases of imported hepatitis E in industrialized countries infected with a genotype 1 hepatitis E virus (HEV) have been identified. We report a 56-year-old Japanese man who acquired infection with a genotype 4 HEV with 98.8% identity to a Vietnamese isolate after ingestion of uncooked shellfish while traveling in Vietnam.

Sporadic acute hepatitis E of a 47-year-old man whose pet cat was positive for antibody to hepatitis E virus

We encountered a patient with sporadic acute hepatitis E who had not traveled to areas endemic for hepatitis E virus (HEV) infection and may have been infected in Japan. The patient was a 47-year-old male who had no history of blood transfusion or contact with travelers to hepatitis E-endemic regions or unspecified individuals. The disease presented with general malaise, fever, and brown urine as chief complaints in April 2002. Various hepatitis virus markers were negative, but IgM class antibodies to hepatitis E virus (anti-HEV) and HEV RNA were positive, and the patient was diagnosed with acute hepatitis E. The entire nucleotide sequence (7240 bases) of HEV (HE-JK4) isolated from this patient was determined and compared with known HEV strains. HE-JK4 belonged to genotype IV and exhibited higher similarities to genotype IV HEV strains previously isolated in Japan than to those isolated in China, Taiwan, and Vietnam. The patients family members living with him were negative for anti-HEV IgG and IgM, but their pet cat was anti-HEV IgG-positive. This finding suggests a potential route of infection of sporadic cases of hepatitis E in Japan. Since the presence of HEV indigenous to Japan is predicted, HEV infection should be considered in the diagnosis of acute hepatitis of unknown cause, even for patients who have not traveled abroad.

Case–control study for the identification of virological factors associated with fulminant hepatitis B

Background:  Host and viral factors can promote the development of fulminant hepatitis B (FHB), but there have been no case–control studies for figuring out virological parameters that can distinguish FHB.

The role of laparoscopic US and laparoscopic US–guided aspiration biopsy in the diagnosis of multicentric hepatocellular carcinoma

BACKGROUND Detection of small hepatocellular carcinomas has become possible with improvements in various diagnostic imaging techniques. However, intraoperative US can detect lesions not visualized by any preoperative imaging study in which case it is difficult to determine whether the lesion is a hepatocellular carcinoma. METHODS Nodular lesions detected by laparoscopic US in 186 patients with hepatocellular carcinoma were examined and we evaluated the diagnostic ability of laparoscopic US to detect multicentric hepatocellular carcinoma. RESULTS One hundred thirty-four new nodular lesions were detected by laparoscopic US in 64 (34.4%) of 186 patients. Aspiration biopsy under laparoscopic US guidance was performed on the 134 nodules, and 28 nodules in 23 (12.4%) of the 186 patients were histologically diagnosed as hepatocellular carcinoma. Of these 23 patients, 18 had been diagnosed with solitary hepatocellular carcinoma before laparoscopic US. One hundred six of the newly detected lesions were initially diagnosed as noncarcinomatous nodules, but the diagnosis of 10 of these lesions was changed to hepatocellular carcinoma during follow-up that was as long as 96 months. CONCLUSIONS Laparoscopic US is useful in the initial diagnosis of hepatocellular carcinoma and impacts treatment selection by more accurately defining the presence of multicentric hepatocellular carcinomas.

Pericryptal fibroblast sheath in intestinal metaplasia and gastric carcinoma

Background and aims: In the progression of chronic gastritis, gastric mucosal cells deviate from the normal pathway of gastric differentiation to an intestinal phenotype which is closely related to gastric carcinoma. However, to date, it has not been elucidated whether the intestinal metaplasia is merely a change in the epithelium or whether the underlying mesenchyme also changes from gastric type to intestinal type. We have investigated the relationship between intestinal metaplasia and the pericryptal fibroblast sheath (PCFS) in the mesenchyme. In addition, we also examined PCFS in gastric carcinoma. Methods: We determined the existence of PCFS in the intestinal metaplastic mucosa and carcinoma of both human and Cdx2 transgenic mouse stomach. PCFS was determined using the antibody against α-smooth muscle actin and electron microscopic observations. Results: PCFS formed an almost complete layer around the small and large intestinal crypts while it did not exist around the normal gastric glands in both mice and humans. PCFS was seen around the glands of intestinal metaplastic mucosa in both Cdx2 transgenic mouse and human stomachs. However, PCFS was virtually absent in the intestinal-type gastric adenocarcinoma area. Conclusion: We successfully demonstrated that the epithelium as well as the mesenchyme changed from the gastric type to the intestinal type in intestinal metaplasia and that PCFS disappeared in intestinal-type gastric carcinoma.

Microwave coagulation therapy for liver cancer: laparoscopic microwave coagulation

A microwave coagulator was developed in 1979 by Tabuse.1 Originally, it was invented as a new cautery device designed to reduce the volume of hemorrhage during hepatectomy. Using the same device, Saitsu et al.2 reported intraoperative and laparoscopic microwave coagulation (MC) therapy for hepatocellular carcinoma (HCC) in 1991. Percutaneous MC was then described by Seki et al.3 in 1994, and the use of MC has rapidly spread since that time. MC for HCC was included in medical insurance coverage in Japan in 1996, and it has since been employed percutaneously, endoscopically (laparoscopy, thoracoscopy), and in open surgery. However, as it has been only 4 years since MC became covered by insurance (and, thus, used widely) in Japan, its clinical value has not yet been established. A representative local therapy for HCC before the advent of MC was percutaneous ethanol injection therapy (PEI), which was introduced around 1983.4,5 Although controversy still continues, there is a general consensus that the results of PEI are comparable to those of surgical resection for HCCs 20mm or less in diameter. Recently, radiofrequency coagulators developed in the United States have been introduced to Japan, and a number of facilities are performing radiofrequency ablation (RA).6–13 The appearance of newer RA devices makes the future position of MC unclear. In particular, as the procedure used for percutaneous MC, which is the most widely performed modality, varies among facilities, and as the criteria for evaluation of its efficacy also differ slightly among facilities, the situation is rather confusing. If the methods differ, the results will also be different. Differences in the approach to cancer are expected to further widen the differences in the results obtained. In this article, we summarize the characteristics and procedures of MC, and review the advantages and disadvantages of MC that have been documented to date, in terms of the approach to cancer. Problems experienced with MC are considered to be similar to those experienced with RA.