Masafumi Naito

Publications (13)63.43 Total impact

• Article: Diuretics aggravate zinc deficiency in patients with liver cirrhosis by increasing zinc excretion in urine.

  Miho Chiba, Kazuhiro Katayama, Risato Takeda, Rie Morita, Kiyoshi Iwahashi, Yoshiki Onishi, Hisaaki Kita, Akira Nishio, Tomoyo Kanno, Tamiko Saito, Kosaku Maeda, Masafumi Naito, Tomoki Michida, Toshifumi Ito
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  ABSTRACT: AIM: Liver cirrhosis is often accompanied by zinc deficiency. The exact mechanisms underlying zinc deficiency remain unclear. This study was undertaken to clarify the influence of diuretics on blood zinc levels and zinc excretion in urine in liver cirrhosis. METHODS: Seventy-nine outpatients with liver cirrhosis were divided into four groups: (i) patients receiving no zinc preparations or diuretics (LC group); (ii) those receiving zinc preparations only (LCZ group); (iii) those receiving diuretics only (LCD group); and (iv) those receiving both zinc preparations and diuretics (LCDZ group). Among these groups, the effects of the administrated drugs on blood zinc levels and urinary zinc excretion were analyzed. RESULTS: Blood zinc levels were significantly lower in the LCD group (47.8  10.5 μg/dL) than in the other groups (LC: 68.8  17.1 μg/dL, P = 0.0056, post-hoc test; LCZ: 78.4  18.1, P < 0.0001; LCDZ: 70.3  21.4, P = 0.0008). The creatinine-adjusted urinary zinc excretion was significantly higher in the LCDZ group (548.1  407.6 μg/mg creatinine) than in the other groups (LC, 58.5  43.7; LCZ, 208.1  227.8; LCD, 105.2  154.4; each P < 0.0001). The fraction of urinary zinc excretion was also significantly higher in the LCDZ group (5.6  2.9%) than in the other groups (LC, 0.6  0.5; LCD, 1.7  1.5; LCZ, 1.6  1.2; each P < 0.0001). CONCLUSION: In patients with liver cirrhosis, treatment with diuretics can increase zinc excretion by suppressing the reabsorption of zinc through renal tubules, which might lead to zinc deficiency.
  Hepatology Research 09/2012; · 2.20 Impact Factor
• Article: Delayed perforation occurring after endoscopic submucosal dissection for early gastric cancer.

  Kenji Ikezawa, Tomoki Michida, Kiyoshi Iwahashi, Kosaku Maeda, Masafumi Naito, Toshifumi Ito, Kazuhiro Katayama
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  ABSTRACT: Delayed perforation occurring after endoscopic submucosal dissection (ESD) is a rare but serious complication which sometimes requires emergent surgery. However, reports of its characteristics, including endoscopic imaging and management, are not fully detailed. A 70-year-old woman was referred to our hospital for the treatment of early gastric cancer. On the day of the ESD, hematemesis was observed because of a Mallory-Weiss tear, and a visible vessel in the post-ESD ulcer was additionally treated endoscopically by coagulation. Second-look endoscopic examination on the next day revealed a perforation 3 mm in diameter at the treated vessel in the ulcer. The shape of the perforation was round and the color of the surrounding muscle layer had become whitish. The perforation was closed with endoclips, and decompression of the pneumoperitoneum was performed. The patient was conservatively managed and was discharged 13 days after the ESD. We show endoscopic images of delayed perforation and discuss the mechanism and management of this complication.
  Gastric Cancer 09/2011; 15(1):111-4. · 2.42 Impact Factor
• Article: [An operated case of retroperitoneal venous hemangioma complicated with Kasabach-Merritt syndrome which was well controlled by danaparoid sodium].

  Aya Moriguchi, Kiyoshi Iwahashi, Yoshiki Onishi, Hisaaki Kita, Akira Nishio, Tomoyo Kanno, Tamiko Matsuura, Kenji Ikezawa, Akiko Ono, Tatsunori Mizuno, Miho Chiba, Kosaku Maeda, Hiroshi Aketa, Masafumi Naito, Tomoki Michida, Kazuhiro Katayama, Yoshio Yamasaki, Tsutomu Kasugai
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  ABSTRACT: A 32-year-old woman was admitted with intermittent rectal bleeding with disseminated intravascular coagulation (DIC)-like coagulopathy. CT and MRI revealed a retroperitoneal tumor, and we diagnosed giant retroperitoneal hemangioma complicated with Kasabach-Merritt syndrome, following blood pool scintigraphy. Corticosteroid and interferon-alpha were not effective, and gabexate mesilate was also ineffective for coagulopathy. Immediately after receiving danaparoid sodium, she recovered from DIC. We performed tumor resection successfully, and she had no symptoms of coagulopathy thereafter.
  Nippon Shokakibyo Gakkai zasshi The Japanese journal of gastro-enterology 11/2009; 106(11):1660-8.
• Article: Hepatitis C Virus Antibodies and Virus Replication in Asymptomatic Blood Donors

  Nobukazu Yuki, Norio Hayashi, Hideki Hagiwara, Masafumi Naito, Kazuyoshi Ohkawa, Akinori Kasahara, Hideyuki Fusamoto, Satoshi Ohtani, Yasuto Okubo, Takenobu Kamada
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  ABSTRACT: We assessed hepatitis C virus (HCV) infection in 99 asymptomatic blood donors positive using a first-generation HCV antibody assay. When tested with second-generation assays, 86 (87%) donors were reactive (group 1), 2 (2%) were indeterminate (group 2), and 11 (11%) were non-reactive (group 3). Viraemia was revealed by polymerase chain reaction in all group 1 cases. The 2 group 2 cases and 6 (55%) group 3 cases were also viraemic. Viraemia was confirmed by a branched DNA assay in the 2 group 2 cases and 4 (36%) group 3 cases. Serum HCV RNA levels were further studied using a competitive reverse transcription-polymerase chain reaction assay. All cases in groups 2 and 3 were low viraemic (range 104–105.5copies/ml) compared with the 9 group 1 cases examined (range 107–109copies/ml). No correlation was evident between viraemic levels and antibody cut-off index in the first-generation assay. These findings indicate the possibility that low levels of viraemia can occur in individuals non-reactive in second-generation HCV antibody assays.
  Vox Sanguinis 03/2009; 67(3):280 - 285. · 2.86 Impact Factor
• Article: Evaluation of the effects of combination therapy with branched‐chain amino acid and zinc supplements on nitrogen metabolism in liver cirrhosis

  Miho Hayashi, Kenji Ikezawa, Akiko Ono, Sachiyo Okabayashi, Yoshito Hayashi, Satoshi Shimizu, Tatsuyoshi Mizuno, Kosaku Maeda, Tomofumi Akasaka, Masafumi Naito, Tomoki Michida, Dan Ueshima, Takayuki Nada, Kiyotaka Kawaguchi, Tekefumi Nakamura, Kazuhiro Katayama
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  ABSTRACT: Aim:  Disorders of protein metabolism in liver cirrhosis can affect prognosis or cause complications. Treatment with branched-chain amino acid (BCAA) and zinc supplements has been shown to be effective against abnormal nitrogen metabolism in liver cirrhosis. There are, however, few studies on the effects of combining these supplements. In this study, the effect of combining BCAA and zinc treatment in cirrhosis was investigated.Methods:  Forty patients with liver cirrhosis who had blood albumin levels of 3.5 g/dL or less and blood zinc levels of 70 μg/dL or less were randomized to receive either BCAA alone or a combination of BCAA and zinc supplements. Blood albumin, the Fischer ratio, and ammonia levels were compared over 5–6 months of treatment.Results:  In the combination group, the post/pre treatment change ratio in blood ammonia levels decreased significantly (0.87 ± 0.26 vs. 1.22 ± 0.38, P = 0.0033), and the change ratio in the Fischer ratio increased significantly (1.22 ± 0.29 vs. 1.08 ± 0.16, P = 0.0165) in comparison with the BCAA monotherapy group. The change ratio in blood albumin levels showed no significant difference between the groups (1.01 ± 0.07 vs. 1.03 ± 0.08, P = 0.4646).Conclusions:  More improvement in disorders of nitrogen metabolism in liver cirrhosis occurred after administration of BCAA with zinc than after BCAA alone over 5–6 months of treatment. Further investigation is necessary to determine mechanisms of the action and longer-term clinical efficacy.
  Hepatology Research 05/2007; 37(8):615 - 619. · 2.20 Impact Factor
• Article: Quantitation of hepatitis C virus RNA in serum of asymptomatic blood donors and patients with type C chronic liver disease

  Hideki Hagiwara, Norio Hayashi M.D, Eiji Mita, Masafumi Naito, Akinori Kasahara, Hideyuki Fusamoto, Takenobu Kamada
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  ABSTRACT: We describe a method for quantifying hepatitis C virus RNA in serum. This competitive assay combines reverse transcription and polymerase chain reaction and is based on coamplification of the target RNA with known amounts of synthetic mutated RNA. We tested serum samples from 104 hepatitis C virus carriers (9 asymptomatic blood donors and 95 patients with type C chronic liver disease) to determine the relationship between the replicative level of hepatitis C virus and various stages of the carrier states. The amount of circulating hepatitis C virus RNA ranged from 104 to 109.5 genomes/ml serum. The titer of hepatitis C virus RNA (logarithmic transformed copy numbers of RNA per milliliter of serum) was lower in asymptomatic blood donors (5.4 ± 2.0) and in patients with chronic persistent hepatitis (7.3 ± 1.1) than in patients with chronic active hepatitis (7.9 ± 0.8), cirrhosis (7.8 ± 0.7) or hepatocellular carcinoma (7.9 ± 0.7). The titer of hepatitis C virus RNA was significantly lower in carriers younger than 40 yr old and correlated positively with the logarithmic transformed serum ALT level. Logistic regression showed that age and titer of hepatitis C virus RNA correlated independently with the stages of liver disease. These results showed that the replicative level of hepatitis C virus is higher in advanced liver disease and that elevation of viral replication may play an important role in liver injury and progression of liver disease. This competitive assay is useful in evaluating the state of viral replication in hepatitis C virus infection. (HEPATOLOGY 1993;17:545–550.)
  Hepatology 12/2005; 17(4):545 - 550. · 11.66 Impact Factor
• Article: Hepatitis C viral quasispecies in hepatitis C virus carriers with normal liver enzymes and patients with type C chronic liver disease

  Masafumi Naito, Norio Hayashi MD, Toyoki Moribe, Hideki Hagiwara, Eiji Mita, Yoshiyuki Kanazawa, Akinori Kasahara, Hideyuki Fusamoto, Takenobu Kamada
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  ABSTRACT: Hepatitis C virus (HCV) has been reported to conform to a quasispecies nature, which is most evident in hypervariable regions of the putative envelope 2 domain. The aim of this study was to determine the relationship between the nucleotide complexity and diversity of hypervariable region 1 and various stages of the carrier states. The subjects studied were 20 HCV carriers with normal alanine aminotransferase (ALT) levels, 50 patients with chronic hepatitis who showed elevated ALT levels, 22 with cirrhosis, and 24 with hepatocellular carcinoma. The quasispecies complexity was analyzed by means of polymerase chain reaction-mediated single strand conformation polymorphism (PCR-SSCP). The value of nucleotide diversity was calculated by PCR cloning and sequencing. The number of SSCP bands ranged from 1 to 7, with no significant differences in the mean numbers among the stages of HCV infection. There was no correlation between the amounts of serum HCV RNA and the numbers of SSCP bands. No significant difference was found in the values of nucleotide diversity between carriers with normal ALT levels (mean, 6.6 × 10−2 per site) and patients with chronic hepatitis (7.7 × 10 −2). These findings suggest that the quasispecies complexity of hypervariable region 1 is independent of the stage of chronic HCV infection. (Hepatology 1995; 22:407–412.)
  Hepatology 12/2005; 22(2):407 - 412. · 11.66 Impact Factor
• Article: [Variation in quasispecies population of blood HCV-RNA in each stage of type C chronic liver disease].

  Masafumi Naito, Kazuhiro Katayama, Norio Hayashi
  Nippon rinsho. Japanese journal of clinical medicine 08/2004; 62 Suppl 7(Pt 1):412-6.
• Article: The significance of interferon and ribavirin combination therapy followed by interferon monotherapy for patients with chronic hepatitis C in Japan.

  Naoki Hiramatsu, Akinori Kasahara, Fumihiko Nakanishi, Takashi Toyama, Masahiko Tsujii, Shingo Tsuji, Tatsuya Kanto, Tetsuo Takehara, Michio Kato, Harumasa Yoshihara, [......], Taizo Hijioka, Hideki Hagiwara, Shinji Kubota, Masahide Oshita, Haruya Meren, Manabu Masuzawa, Yoshimichi Haruna, Eiji Mita, Kunio Suzuki, Norio Hayashi
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  ABSTRACT: One hundred seventy-one patients with chronic hepatitis C were included in this study (genotype1 and high viral loads (1H), [Formula: see text]; non-1H, [Formula: see text]; N.D., [Formula: see text] ). The combination therapy of interferon and ribavirin for 24 weeks with an additional 24 weeks of interferon monotherapy (48-week treatment) was undergone by 42 1H patients and 5 non-1H patients. The combination therapy of interferon and ribavirin was administered for 24 weeks in 67 1H patients and 22 non-1H patients. Among the 1H patients, the HCV relapse rate was significantly higher in those receiving 24-week combination treatment than in those receiving 48-week treatment (78% versus 42%, [Formula: see text] ). Among the non-1H patients, no significant difference was found between them. Sustained virological response (SVR) rates were observed to decrease as the timing of HCV RNA disappearance was delayed. In spite of the small rate (16%), SVR was obtained from the patients who became negative for HCV RNA by week 24 (beyond week 12) only in those receiving 48-week treatment. In 1H patients, 24-week combination treatment followed by interferon monotherapy for 24 weeks was concluded to be the treatment offering the most hope among those that the medical insurance can be applied in Japan.
  Hepatology Research 08/2004; 29(3):142-147. · 2.20 Impact Factor
• Article: Saline injection into the pleural cavity to detect tumors of the hepatic dome with sonography: a new approach for treatment of hepatocellular carcinoma.

  Kazuhiro Katayama, Yuko Ooka, Akio Uemura, Shinichiro Shinzaki, Satoshi Egawa, Masafumi Naito, Kazunobu Ishibashi, Ryuichi Kamoi
  American Journal of Roentgenology 08/2002; 179(1):102-4. · 2.78 Impact Factor
• Article: Long-term biochemical and virological response to natural interferon-α in patients with chronic hepatitis C

  Hideki Hagiwara, Norio Hayashi, Akinori Kasahara, Masahide Oshita, Kazuhiro Katayama, Masafumi Naito, Manabu Masuzawa, Harumasa Yoshihara, Yoji Shimizu, Hideyuki Fusamoto, Takenobu Kamada
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  ABSTRACT: To determine the long-term response to interferon-, 134 patients with chronic hepatitis C were followed for more than one year after therapy. Follow-up was stopped for 14 patients and 43 patients received retreatment. The remaining 77 patients were followed for 26–46 months, and 39 of them achieved long-term sustained alanine aminotransferase (ALT) normality. This normality was achieved in 35/38 short-term sustained responders, which was significantly higher (P
  Digestive Diseases and Sciences 01/1996; 41(5):1001-1007. · 2.12 Impact Factor
• Article: Increased serum hepatitis C virus RNA levels among alcoholic patients with chronic hepatitis C

  Masahide Oshita, Norio Hayashi M.D, Akinori Kasahara, Hideki Hagiwara, Eiji Mita, Masafumi Naito, Kazuhiro Katayama, Hideyuki Fusamoto, Takenobu Kamada
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  ABSTRACT: Hepatitis viruses and alcohol are major causes of liver disease. This study was aimed at investigating the effect of alcohol intake on the replication of hepatitis C virus and the efficacy of interferon therapy. Fiftythree patients who were histologically proved to have chronic hepatitis C were tested. Of these, 16 were diagnosed as habitual drinkers whose cumulative total consumption of alcohol was more than 100 kg or who had consumed at least 60 gm of ethanol daily for at least 5 yr. The quantities of hepatitis C virus RNA in serum were measured with a competitive assay that combined reverse transcription and polymerase chain reaction. The subjects received a 26-wk course of interferon-α therapy. There were no significant differences in age and ALT levels between habitual drinkers and nonhabitual drinkers. The titer of viral RNA (logarithmic transformed copy numbers per milliliter of serum) of habitual drinkers (8.5 ± 0.5) was higher than that of nonhabitual drinkers (7.7 ± 0.8) (p < 0.01). Neopterin levels in serum, a marker for the activation of cellmediated immunity, were lower for habitual drinkers (5.7 ± 1.5 pmol/ml) than for nonhabitual drinkers (8.1 ± 5.0 pmol/ml) (p < 0.01). Eleven of the nonhabitual drinkers (30%) were long-term responders whose alanine aminotransferase levels remained within normal range during the 24 wk after interferon therapy, whereas only one (6%) of the habitual drinkers was a long-term responder (p = 0.06). These findings suggest that alcohol intake increases hepatitis C virus RNA levels in serum—at least in part—impairment of cellular immunity, and modulates the efficacy of interferon therapy. (Hepatology 1994;20:1115–1120).
  Hepatology 10/1994; 20(5):1115 - 1120. · 11.66 Impact Factor
• Article: Buoyant density of hepatitis C virus recovered from infected hosts: Two different features in sucrose equilibrium density‐gradient centrifugation related to degree of liver inflammation

  Tatsuya Kanto, Norio Hayashi M.D, Tetsuo Takehara, Hideki Hagiwara, Eiji Mita, Masafumi Naito, Akinori Kasahara, Hideyuki Fusamoto, Takenobu Kamada
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  ABSTRACT: Hepatitis C virus is reported to have a low buoyant density in sucrose. To determine the density of hepatitis C virus in the circulation of infected hosts and its association with the degree of liver inflammation, we examined serum samples from 10 patients who were positive for both hepatitis C virus antibody (C100 antigen) antibody and serum hepatitis C virus RNA. After the serum was ultracentrifuged in sucrose density gradient (10 to 60), the hepatitis C virus RNA titer in each collected fraction was quantified by means of competitive reverse transcription–polymerase chain reaction. In samples from five blood donors, the hepatitis C virus RNA titer had a single peak at fractions with densities of 1.08 to 1.11 gm/ml. In samples from five patients with ALT abnormalities, the titer had two peaks at fractions with 1.09 to 1.10 gm/ml and 1.22 to 1.25 gm/ml. After the selected samples were treated with detergents and ultracentrifuged, the titer in the 1.08 to 1.11 gm/ml fractions decreased and that in the 1.22 to 1.25 gm fractions increased. This result implied that the hepatitis C virus density changed with removal of the viral envelope by lipid solvents. Thus the buoyant density of hepatitis C virus in sucrose was 1.08 to 1.11 gm/ml for an intact virion and 1.22 to 1.25 gm/ml for what was presumed to be a nucleocapsid. These results demonstrated that HCV virion is a dominant form in the circulation of blood donors without ALT abnormalities. In patients with liver inflammation HCV particles with higher densities of 1.22 to 1.25 gm/ml coexist with virion in the circulation, which might be presumed nucleocapsids. (Hepatology 1994;19:296–302).
  Hepatology 01/1994; 19(2):296 - 302. · 11.66 Impact Factor