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Dive into the research topics where Masafumi Komatsu is active.

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Featured researches published by Masafumi Komatsu.


Journal of Clinical Microbiology | 2009

Distribution of Hepatitis B Virus Genotypes among Patients with Chronic Infection in Japan Shifting toward an Increase of Genotype A

Kentaro Matsuura; Yasuhito Tanaka; Shuhei Hige; Gotaro Yamada; Yoshikazu Murawaki; Masafumi Komatsu; Tomoyuki Kuramitsu; Sumio Kawata; Eiji Tanaka; Namiki Izumi; Chiaki Okuse; Shinichi Kakumu; Takeshi Okanoue; Keisuke Hino; Yoichi Hiasa; Michio Sata; Tatsuji Maeshiro; Fuminaka Sugauchi; Shunsuke Nojiri; Takashi Joh; Yuzo Miyakawa; Masashi Mizokami

ABSTRACT Acute hepatitis B virus (HBV) infection has been increasing through promiscuous sexual contacts, and HBV genotype A (HBV/A) is frequent in patients with acute hepatitis B (AHB) in Japan. To compare the geographic distribution of HBV genotypes in patients with chronic hepatitis B (CHB) in Japan between 2005 and 2006 and between 2000 and 2001, with special attention to changes in the proportion of HBV/A, a cohort study was performed to survey changes in genotypes of CHB patients at 16 hospitals throughout Japan. Furthermore, we investigated the clinical characteristics of each genotype and examined the genomic characteristics of HBV/A isolates by molecular evolutionary analyses. Of the 1,271 patients, 3.5%, 14.1%, and 82.3% were infected with HBV/A, -B, and -C, respectively. In comparison with our previous survey during 2000 and 2001, HBV/A was twice as frequent (3.5% versus 1.7%; P = 0.02). The mean age was lower in the patients with HBV/A than in those with HBV/B or -C. Based on phylogenetic analyses of 11 full-length genomes and 29 pre-S2/S region sequences from patients, HBV/A isolates were imported from Europe and the United States, as well as the Philippines and India. They clustered with HBV/A from AHB patients and have spread throughout Japan. HBV/A has been increasing in CHB patients in Japan as a consequence of AHB spreading in the younger generation through promiscuous sexual contacts, aided by a tendency of HBV/A to induce chronic hepatitis. The spread of HBV/A infection in Japan should be prevented by universal vaccination programs.


Clinical Infectious Diseases | 2004

Two Subtypes of Genotype B (Ba and Bj) of Hepatitis B Virus in Japan

Fuminaka Sugauchi; Hiroshi Sakugawa; Masafumi Komatsu; Hirofumi Niitsuma; Hisayoshi Watanabe; Yoshihiro Akahane; Hajime Tokita; Takanobu Kato; Yasuhito Tanaka; Etsuro Orito; Ryuzo Ueda; Yuzo Miyakawa; Masashi Mizokami

We have previously reported 2 subtypes of hepatitis B virus (HBV) genotype B, one of which has the recombination with genotype C over the precore region plus core gene (Ba) and the other of which does not (Bj). A restriction fragment-length polymorphism method with 2 endonucleases was newly developed for distinguishing between subtypes Ba and Bj and was applied to 313 carriers of HBV genotype B in Japan. Subtype Ba was detected in 38 (12%) and subtype Bj in 275 (88%) of the carriers of HBV genotype B. Hepatitis B e antigen in serum was found more frequently in patients with chronic infection with subtype Ba than in those with chronic infection with subtype Bj (8 [32%] of 25 vs. 25 [9%] of 273; P<.01). The new method for distinguishing between Ba and Bj by restriction fragment-length polymorphism would be useful in examining the distribution of these 2 subtypes in situations in which HBV genotype B is prevalent.


International Journal of Colorectal Disease | 2002

Systemic and local evidence of increased Fas-mediated apoptosis in ulcerative colitis

Michihiro Yukawa; Masahiro Iizuka; Yasuo Horie; Kazuo Yoneyama; Tomoyuki Shirasaka; Hiroaki Itou; Masafumi Komatsu; Tsuneo Fukushima; Sumio Watanabe

Abstract. Background and aims: Recent studies suggest that Fas-mediated apoptosis is involved in the pathogenesis of inflammatory bowel disease (IBD). This study was conducted to clarify whether soluble forms of Fas (sFas) and Fas ligand (sFasL) are concerned with inflammation in IBD. Methods and patients: Concentration of serum sFas and sFasL was measured by enzyme-linked immunosorbent assay in 10 patients with ulcerative colitis (UC), 10 with Crohns disease (CD) in both active and remission stages, and 20 controls. Expression of Fas and sFas in colonic mucosa was examined by western blot. Distribution of Fas and FasL in colonic mucosa was examined by immunohistochemistry in 20 UC, 20 CD, and 10 non-IBD colitis patients and in 10 controls. Apoptotic cells were examined by TUNEL. Results: Concentration of systemic sFas was significantly lower in active UC than controls. The number of FasL-containing cells was significantly higher in active UC than in remission UC, non-IBD colitis, and controls. Apoptotic cells were increased in active UC. Conclusions: Our results demonstrate that systemic and local Fas-mediated apoptosis is promoted in UC, which might be involved in the pathogenesis in UC.


British Journal of Ophthalmology | 1999

Decreased tear lactoferrin concentration in patients with chronic hepatitis C

Tohru Abe; Ako Nakajima; Mutsumi Matsunaga; Shozo Sakuragi; Masafumi Komatsu

BACKGROUND/AIMS Decreased tear volume in patients with chronic hepatitis C has been reported in the literature. Lactoferrin is abundantly present in human tears, the main source of which is the acini of the lacrimal glands. In this study tear lactoferrin levels were measured to investigate the dry eye condition of patients with chronic hepatitis C. METHODS Lactoferrin in tears/fluid was measured by a radial immunodiffusion assay in 42 patients with chronic hepatitis C. The rate of lacrimal secretion was determined by the cotton thread test. Rose bengal staining of the ocular surface was also performed. RESULTS Only three patients out of 42 complained of dry eye sensation and, in 31 patients, six showed positive results on the rose bengal staining test of the ocular surface. The lactoferrin concentration of tear fluid in the chronic hepatitis C group (1.42 (SD 0.56) mg/ml) was significantly lower than in the control group (1.90 (0.62) mg/ml; p <0.00048). The cotton thread test results in the chronic hepatitis C group (12.9 (5.5) mm) were significantly lower than in the control group (17.9 (5.3) mm; p<0.00048). Also, in the chronic hepatitis C group, tear lactoferrin concentration correlated with the results of the cotton thread test (r = 0.35, p<0.05). CONCLUSION Chronic hepatitis C patients showed both decreased tear volume, and decreased tear lactoferrin concentration. These findings suggest that there may be dysfunction of the lacrimal glands in patients with chronic hepatitis C, which may account for the mild dry eye.


Journal of Gastroenterology and Hepatology | 1996

Relationship between hepatocellular carcinoma and subtypes of hepatitis C virus: a nationwide analysis.

Akira Takada; Mikihiro Tsutsumi; Shun-Cai Zhang; Takeshi Okanoue; Takashi Matsushima; Shigetoshi Fujiyama; Masafumi Komatsu

Although hepatitis C virus (HCV) has now been classified into several subtypes, the clinical significance of HCV subtypes is not well known. Typing of HCV is now routinely performed in Japan. In the present study, HCV subtypes in hepatocellular carcinoma (HCC) patients were analysed from nationwide data collected in Japan using a standard questionnaire. Answers to the questionnaire concerning HCV subtypes in patients with chronic hepatitis (CH), liver cirrhosis (LC) and HCC were obtained from 14 hospitals. The prevalence of the 1b‐related subtype, which includes the mixed subtype of 1b and 2a or 2b, in patients with LC and HCC in each hospital was higher than in patients with CH, with few exceptions. However, the differences were not statistically significant because of the small number of patients in each hospital. In summarized data from all 14 hospitals, the 1b‐related subtype was found in 1370 of 1922 patients with CH (71.2%). In 356 LC and 426 HCC patients, the prevalence of the 1b‐related subtype was 79.8 and 80.5%, respectively. The prevalence of the 1b‐related subtype in patients with LC and HCC was significantly higher than in patients with CH. There was no significant difference between the prevalence of the 1b‐related subtype in patients with HCC and LC. These results indicate that the oncogenic activity of subtype 1b, although not yet clearly characterized, may be stronger than subtypes 2a and 2b.


Digestive Diseases and Sciences | 1997

Induction of a 72-kDa Heat Shock Protein and Cytoprotection Against Thioacetamide-Induced Liver Injury in Rats

Shusei Fujimori; Michiro Otaka; Setsuya Otani; Mario Jin; Atsushi Okuyama; Satoshi Itoh; Akira Iwabuchi; Hideaki Sasahara; Hideaki Itoh; Yohtalou Tashima; Masafumi Komatsu; Osamu Masamune

Heat shock proteins are ubiquitous intracellularproteins induced by various physiological stress-relatedevents. A 72-kDa heat shock protein (HSP72) has beenreported to be an endogenous cytoprotectant in variety of cells in vitro . In order tostudy the cytoprotective function of HSP72 in the liver,the effect of preinduction of HSP72 in rat liver bysystemic hyperthermia on thioacetamide-induced hepatic injury was investigated in this study.Expression of HSP72 in the liver was investigated byimmunoblot and densitometric analysis. Rats wereinjected with thioacetamide (100 mg/kg, subcutaneously)with or without preinduction of HSP72 byhyperthermia. Serum AST and ALT concentrations weremeasured before and after thioacetamide injection inboth group. Histologic alteration of the liver wasevaluated also. Systemic hyperthermia (42.5°C, 20min) significantly induced HSP72 in the liver.Thioacetamide-induced hepatic injury was clearlyprevented by preinduction of HSP72 by hyperthermia.Prevention of hepatocyte damage was more clear in the areaaround central veins where HSP72 induction was apparent.Our findings might suggest that HSP72 has an importantfunction in the liver with respect to cytoprotection. These results might be important forunderstanding the mechanism of “adaptivecytoprotection” in the liver mediated by thefunction of heat shock proteins as “molecularchaperons” as reported in vitro.


The Permanente Journal | 2015

High Amount of Dietary Fiber Not Harmful But Favorable for Crohn Disease

Mitsuro Chiba; Tsuyotoshi Tsuji; Kunio Nakane; Masafumi Komatsu

Current chronic diseases are a reflection of the westernized diet that features a decreased consumption of dietary fiber. Indigestible dietary fiber is metabolized by gut bacteria, including Faecalibacterium prausnitzii, to butyrate, which has a critical role in colonic homeostasis owing to a variety of functions. Dietary fiber intake has been significantly inversely associated with the risk of chronic diseases. Crohn disease (CD) is not an exception. However, even authors who reported the inverse association between dietary fiber and a risk of CD made no recommendation of dietary fiber intake to CD patients. Some correspondence was against advocating high fiber intake in CD. We initiated a semivegetarian diet (SVD), namely a lacto-ovo-vegetarian diet, for patients with inflammatory bowel disease. Our SVD contains 32.4 g of dietary fiber in 2000 kcal. There was no untoward effect of the SVD. The remission rate with combined infliximab and SVD for newly diagnosed CD patients was 100%. Maintenance of remission on SVD without scheduled maintenance therapy with biologic drugs was 92% at 2 years. These excellent short- and long-term results can be explained partly by SVD. The fecal bacterial count of F prausnitzii in patients with CD is significantly lower than in healthy controls. Diet reviews recommend plant-based diets to treat and to prevent a variety of chronic diseases. SVD belongs to plant-based diets that inevitably contain considerable amounts of dietary fiber. Our clinical experience and available data provide a rationale to recommend a high fiber intake to treat CD.


Hepatology Research | 2002

The expression of Fas and Fas ligand, and the effects of interferon in chronic liver diseases with hepatitis C virus

Kazuo Yoneyama; Takashi Goto; Kouichi Miura; Ken-ichirou Mikami; Shigetoshi Ohshima; Kunio Nakane; Jiun Guey Lin; Masashiro Sugawara; Norio Nakamura; Kamon Shirakawa; Masafumi Komatsu; Sumio Watanabe

In viral hepatitis, binding of Fas ligand (FasL) with Fas expressed on the surfaces of infected hepatocytes induces apoptosis, removing hepatitis virus along with infected hepatocytes. We measured serum concentrations of soluble Fas (sFas) and FasL (sFasL), expression of membrane-bound FasL, and expression of FasL-mRNA in patients with chronic hepatitis C without cirrhosis (CH-C) and chronic hepatitis C with liver cirrhosis (LC-C). In CH-C, sFasL concentrations were lower and FasL-mRNA expression was significantly less than in volunteers. In LC-C, sFas concentrations were significantly greater than in healthy volunteers, while sFasL, membrane-bound FasL expression, and FasL-mRNA expression did not show significant differences. We also examined these variables over 24 h following the first interferon (IFN) treatment in patients with CH-C. Serum concentrations of sFas and sFasL, and FasL-mRNA expression increased markedly beyond amounts present before IFN injection until 12 h after IFN injection. However, membrane-bound FasL expression decreased until 6 h, followed by an increase until 24 h. Our findings suggest that the ratio of membrane-bound FasL to sFasL may be regulated to remove virally infected cells in CH-C. In addition, apoptosis mediated by the Fas/FasL system may be influenced by IFN injection for treatment of CH-C.


Journal of Gastroenterology and Hepatology | 1996

Distribution of the different subtypes of hepatitis C virus in Japan and the effects of interferon: A nationwide survey

Akira Takada; Mikihiro Tsutsumi; Takeshi Okanoue; Takashi Matsushima; Masafumi Komatsu; Shigetoshi Fujiyama

Interferon (IFN) is now commonly used for the treatment of type C hepatitis; however, its effects differ depending upon the subtype of hepatitis C virus (HCV) being treated. It has been recently confirmed in many studies in Japan that the effectiveness of IFN treatment is poor in patients having type 1b and better in patients having type 2a HCV. However, the effects of IFN treatment on other subtypes of HCV were not clear because of the small number of patients in each hospital. In the present study, the effects of IFN treatment in patients with other HCV subtypes were analysed from nationwide data collected in Japan using a standard questionnaire. From this questionnaire, local differences in the distribution of HCV subtypes in Japan were also analysed. A standard questionnaire, consisting of questions about the number of patients with chronic type C hepatitis with different HCV subtypes and the number of patients showing different responses to IFN treatment, was sent to over 40 study groups in Japan, Answers to the questionnaire concerning HCV subtyes and the effects of IFN treatment were obtained from 26 and 22 hospitals, respectively, throughout Japan. The incidence of HCV type 1b was highest in the Kinki area (south‐central Japan). The incidence of type 1b HCV decreased in parallel with distance from this area. The mortality rates of hepatic cancer in different areas were significantly corrclated with the incidence of HCV type 1b. The efficacy of IFN treatment was significantiy better for both types 2a and 2b HCV than for type 1b HCV; the efficacy of IFN treatment was poor in the mixed type of 1b and 2a and tended to be better in type 1a. The efficacy of IFN treatment for other types of HCV was also better. These results indicate that there are local differences in the distribution of HCV subtypes in Japan and that these differences may be closely associated with the clinical features of HCV‐related liver disease. The efficacy of IFN treatment was significantly poorer in patients with the 1b‐related type HCV than in patients with other types of HCV.


Journal of Gastroenterology | 1996

Alpha-fetoprotein, carcinoembryonic antigen, and carbohydrate antigen 19-9-producing gallbladder cancer

Tsuyoshi Ono; Masafumi Komatsu; Takao Hoshino; Tohru Ishii; Tomoo Fujii; Shigetoshi Oshima; Ken-ichiro Mikami; Yasuhiro Umeki; Katsuhiko Enomoto; Osamu Masamune

We report a rare case of alpha-fetoprotein (AFP), carcinoembryonic antigen (CEA), and carbohydrate antigen (CA) 19-9-producing gallbladder cancer with high levels of CA125 and protein induced by vitamin K absence or antagonist II (PIVKA II). A 63-year-old man was diagnosed with gallbladder cancer with metastases to the liver, based on ultrasonography and computed tomography of the abdomen showing multiple tumorous lesions in the liver and a thickened gallbladder wall. Laboratory data showed high levels of tumor markers: 4647.4 ng/ml AFP, 9987.1 ng/ml CEA, 11704.0 U/ml CA19-9, 847.6 U/ml CA125, and 0.2 AU/ml PIVKA II. AFP in the present case showed an increase in Concanavalin A-nonbinding fraction and an increase inLens culinaris lectin-binding fraction by affinity column chromatography. The patient died of hepatic failure. Autopsy revealed gallbladder cancer consisting of papillary adenocarcinoma and moderately differentiated tubular adenocarcinoma. By immunohistochemical staining, AFP was detected in the papillary adenocarcinoma portion of the primary focus and metastatic tumor cells in the liver, but was not detected in noncancerous liver tissue. CEA and CA19-9 were detected mainly in the tubular adenocarcinoma portion.

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