Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Masayuki Nakano is active.

Publication


Featured researches published by Masayuki Nakano.


Cancer | 1996

Multiple primary esophageal and concurrent upper aerodigestive tract cancer and the aldehyde dehydrogenase-2 genotype of Japanese alcoholics

Akira Yokoyama; Taro Muramatsu; Tai Ohmori; Hiroyasu Makuuchi; Susumu Higuchi; Sachio Matsushita; Keiichi Yoshino; Katsuya Maruyama; Masayuki Nakano; Hiromasa Ishii

Multiple intraesophageal primary cancer and upper aerodigestive tract (UADT) cancer associated with esophageal cancer are common diseases, especially in heavy drinkers. They are often explained by the concept of field cancerization, which suggests a similar etiology. However, little is known about the nature of the hypothesized etiology.


The Lancet | 1998

Irregular regeneration of hepatocytes and risk of hepatocellular carcinoma in chronic hepatitis and cirrhosis with hepatitis-C-virus infection

Minoru Shibata; Toshio Morizane; Toshikazu Uchida; Tomoyuki Yamagami; Yasushi Onozuka; Masayuki Nakano; Keiji Mitamura; Yukihisa Ueno

BACKGROUND Hepatocellular carcinoma (HCC) commonly develops in patients with chronic hepatitis or cirrhosis of the liver caused by hepatitis-C-virus (HCV) infection. We prospectively studied whether irregular regeneration of hepatocytes is a risk factor for HCC in these patients. METHODS 242 patients were enrolled after liver biopsy and followed up by ultrasonographic scanning every 3 months. We examined age, sex, platelet count, the diagnosis of cirrhosis or chronic hepatitis, liver-cell dysplasia, and irregular regeneration. We classified irregular regeneration as slight or severe, based on histological expression of pleiomorphism, anisocytosis, bulging, and map-like distribution of hepatocytes. FINDINGS 37 of 63 patients with cirrhosis and 26 of 179 with chronic hepatitis were judged to have severe irregular regeneration. HCC was diagnosed in 33 of 63 patients with cirrhosis (29 had severe irregular regeneration) and 12 of 179 patients with chronic hepatitis (11 had severe irregular regeneration) during mean follow-up of 5.5 years (SD 4.1; range 1-16). Multivariate analysis with a proportional-hazards model showed severe irregular regeneration (relative risk 15.1 [95% CI 5.6-40.7], p<0.0001) and a diagnosis of cirrhosis (3.8 [1.7-8.2], p=0.0008) to be significant risk factors for HCC. Within the diagnostic categories, irregular regeneration was also significant (cirrhosis 6.8 [2.1-21.9], p=0.0014; chronic hepatitis 28.5 [2.9-276.4], p=0.0038). INTERPRETATION We recommend that liver biopsy to look for irregular regeneration should be done in patients with HCV-related chronic liver diseases. Those with severe irregular regeneration should be followed up carefully.


Journal of Surgical Oncology | 1998

Does gross appearance indicate prognosis in intrahepatic cholangiocarcinoma

Masakazu Yamamoto; Ken Takasaki; Tatsuya Yoshikawa; Keiko Ueno; Masayuki Nakano

Survival after surgery for intrahepatic cholangiocarcinoma (ICC) is usually poor. The objective of this study was to investigate whether the gross appearance of ICC indicates postoperative prognosis.


Cancer | 1993

Hepatitis C virus antibody in patients with primary liver cancer (hepatocellular carcinoma, cholangiocarcinoma, and combined hepatocellular-cholangiocarcinoma) in Japan

Masahiko Tomimatsu; Noriko Ishiguro; Makiko Taniai; Hiroaki Okuda; Akiko Saito; Hiroshi Obata; Masakazu Yamamoto; Ken Takasaki; Masayuki Nakano

Background. In hepatocellular carcinoma (HCC), a high prevalence of hepatitis C virus antibody (anti‐HCV) has been reported, indicating that it may be an important etiologic factor in the pathogenesis of HCC. In this study, the authors investigated the prevalence of anti‐HCV in HCC patients, as well as the same prevalence in patients with cholangiocarcinoma (CC) and combined hepatocellular–cholangiocarcinoma (combined HCC‐CC), to study the clinicopathologic features of anti‐HCV–positive cases.


Cancer | 2000

Serum levels of des‐γ‐carboxy prothrombin measured using the revised enzyme immunoassay kit with increased sensitivity in relation to clinicopathologic features of solitary hepatocellular carcinoma

Hiroaki Okuda; Toshimi Nakanishi; Kazuko Takatsu; Akiko Saito; Naoaki Hayashi; Ken Takasaki; Kazuyuki Takenami; Masakazu Yamamoto; Masayuki Nakano

Des‐γ‐carboxy prothrombin (DCP) is an established marker for hepatocellular carcinoma (HCC), but the conventional enzyme immunoassay (EIA) kit lacks adequate sensitivity. Thus, a revised EIA kit with increased sensitivity has been developed. In this kit, the sensitivity has increased while high specificity to HCC has been maintained. The authors have already reported the clinical usefulness of this revised EIA kit. In this study, they examined the serum levels of DCP measured by this revised EIA kit in relation to the clinicopathologic features of solitary HCC.


Cancer | 1998

Minute nodular intrahepatic cholangiocarcinoma

Masakazu Yamamoto; Ken Takasaki; Masayuki Nakano; Akiko Saito

This study describes the clinicopathologic features of minute intrahepatic cholangiocarcinoma (ICC) and clarifies the relation between minute nodular ICC and hepatitis viral infection.


Cancer Letters | 2000

The role of orally administered dimethylarsinic acid, a main metabolite of inorganic arsenics, in the promotion and progression of UVB-induced skin tumorigenesis in hairless mice

Kenzo Yamanaka; Koichi Katsumata; Kazuhiro Ikuma; Akira Hasegawa; Masayuki Nakano; Shoji Okada

The effect of dimethylarsinic acid (DMA) on skin tumorigenesis by UVB irradiation was examined. Hairless mice (Hos: HR-1) irradiated with UVB at a dose of 2 kJ/m(2) twice weekly, were fed with drinking water containing 1000 ppm DMA, a main metabolite of inorganic arsenics, produced more skin tumors than DMA-untreated mice. Histopathological examination revealed that the mouse malignant tumors with severe atypism appeared only in the treatment group of UVB plus 1000 ppm DMA. These positive results point out the importance of dimethylated metabolites of inorganic arsenic in the process of skin carcinogenesis.


Gastroenterology | 1987

Portal hemodynamics in idiopathic portal hypertension (Banti's syndrome): Comparison with chronic persistent hepatitis and normal subjects

Kunihiko Ohnishi; Saito M; Shinichi Sato; Hidetaka Terabayashi; Shinji Iida; Fumio Nomura; Masayuki Nakano; Kunio Okuda

A comparative study of portal hemodynamics was made in 17 patients with idiopathic portal hypertension, 5 patients with chronic persistent hepatitis having no portal hypertension, and 21 healthy adults who served as the control for certain measurements. Venous pressures were measured by portal and hepatic vein catheterizations, blood flow by the pulsed Doppler flowmeter, organ volume by computed tomography, and intrahepatic shunt index by 99mTc-macroaggregated albumin instilled in the portal vein. The patients with idiopathic portal hypertension were divided into two groups: group A (n = 8) and group B (n = 9), consisting of those who respectively had portal venous flow per liver volume above and below the mean + 2 SD of healthy adults. In group A, portal vein pressure was moderately elevated, portal venous flow was significantly increased compared with the control, and portal vascular resistance was not much altered. In group B, portal vein pressure was markedly elevated above that of control, portal venous flow was comparable, and portal vascular resistance was significantly elevated. Splenic venous flow measured in the splenic vein between the left and short gastric veins was markedly increased in groups A and B, the increase being greater in the former. It was concluded that in some patients with idiopathic portal hypertension, increased portal venous flow, partly a result of increased splenic venous flow secondary to splenomegaly of an undetermined process, is the main contributor initially to the elevation of portal vein pressure; in others, possibly later, increased portal vascular resistance plays an important role.


Archives of Toxicology | 1997

Time courses of hepatic injuries induced by chloroform and by carbon tetrachloride: comparison of biochemical and histopathological changes

Pei-Yu Wang; Takashi Kaneko; Hiroshi Tsukada; Masayuki Nakano; Tamie Nakajima; Akio Sato

The relationship was investigated between biochemical and morphological changes in chloroform (CHCl3)- and carbon tetrachloride (CCl4)-induced liver damage. The time courses of hepatic microsomal cytochrome P450 (CYP) content, hepatic microsomal CYP2E1 activity, hepatic reduced glutathione (GSH) content, plasma alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities were examined in relation to the liver morphology in rats orally treated with CHCl3 or CCl4 (3.35 mmol/kg). The CYP content and the activity of CYP2E1 markedly decreased in the CCl4-treated rats 3 h after treatment compared to much lower decreases in the CHCl3-treated rats. The hepatic GSH content was decreased to a similar extent in both groups of rats at 3 h after treatment; in the CCl4-treated rats, the GSH content continued to decrease, reaching a minimum at 24 h and without attaining the normal level at 72 h after treatment. By contrast, hepatic GSH content in the CHCl3-treated rats began to increase from 6 h, attaining complete recovery 48 h after treatment. Plasma ALT and AST activities were significantly elevated by CCl4 as early as 3 h after treatment, while the activities in the CHCl3-treated rats did not increase until 6 h after treatment. In both groups of rats, ALT and AST activities reached a maximum at 24 h, and gradually decreased, remaining at abnormal levels at 72 h. Hepatic cells in the CCl4-treated rats were found to be necrotic as early as 3 h post-treatment, whereas few or no morphological changes appeared in the liver of CHCl3-treated rats. The extent of necrosis was at a maximum 24 h after treatment in both CHCl3- and CCl4-treated rats. In addition, some necrotic cells remained in the liver of CCl4-treated rats 72 h after treatment, while the necrosis in the CHCl3-treated rats was almost negligible. The present results indicate that almost the same time-courses of biochemical and morphological changes were followed in rats of both the CHCl3- and CCl4-treated groups.


Alcoholism: Clinical and Experimental Research | 1999

Genotypes of Alcohol‐Metabolizing Enzymes in Relation to Alcoholic Chronic Pancreatitis in Japan

Katsuya Maruyama; Hisao Takahashi; Sachio Matsushita; Masayuki Nakano; Hideo Harada; Makoto Otsuki; Michio Ogaw; Kouichi Suda; Tadao Baba; Tatsuji Honma; Toshio Moroboshi; Masaki Matsuno

Long-term consumption of large amounts of alcohol is the main cause of chronic pancreatitis. All heavy drinkers, however, do not contract chronic pancreatitis. Although genetic predisposition to alcoholism and alcoholic liver disease has been reported, genetic susceptibility to alcoholic pancreatitis is still a matter of debate. To determine the relation between genotypes of alcohol-metabolizing enzymes and chronic alcoholic pancreatitis, we examined genotype patterns of aldehyde dehydrogenase 2 (ALDH 2), alcohol dehydrogenase 2 (ADH 2) and cytochrome P-4502E1 (CYP2E1) in 54 patients with chronic alcoholic pancreatitis who were diagnosed in general hospitals in all over Japan and compared with those in 30 patients with chronic nonalcoholic pancreatitis or in 46 alcoholics with normal pancreatic function. There were no significant differences in the distribution of genotypes of ALDH 2 and CYP2E1 among those three groups. As for the ADH 2 genotype, distribution of 21 /21 ,21 /22 , and 22 /22 was 35%, 30%, and 35% in alcoholics with normal pancreatic function; 4%, 39%, and 57% in the chronic alcoholic pancreatitis group; and 0%, 50%, and 50% in the chronic nonalcoholic pancreatitis group, respectively. The frequency of ADH 22 allele was significantly higher in the chronic alcoholic pancreatitis group, compared with alcoholics with normal pancreatic function; but, it was not significantly different from that in the chronic nonalcoholic pancreatitis group. We also examined the relation between pancreatic fibrosis or pancreatitis histologically diagnosed and genotypes of alcohol-metabolizing enzymes in alcoholic autopsy cases. Twenty of 31 cases showed moderate or severe pancreatic fibrosis and showed intralobular + interlobular fibrosis, which is characteristic in alcoholic pancreatitis or intralobular fibrosis. ADH 22 allele tended to show a high frequency in the intralobular + interlobular fibrosis group, compared with that in the intralobular fibrosis group (75.0% vs. 41.7%, p < 0.1). The chronic pancreatitis group had a significantly higher frequency of the ADH 22 allele than that in cases without such findings (87.5% vs. 58.7%, p < 0.05). However, the ALDH 2 and CYP2E1 genotypes showed no significant relation to the findings of pancreatic fibrosis or histological pancreatitis. These data suggest that the risk of chronic alcoholic pancreatitis diagnosed clinically and pathologically seems to be associated with the ADH 22 allele in the genotypes of alcohol-metabolizing enzymes.

Collaboration


Dive into the Masayuki Nakano's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar

Shoji Okada

College of Science and Technology

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Katsuya Maruyama

Icahn School of Medicine at Mount Sinai

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge