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Dive into the research topics where Hiroo Ohnishi is active.

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Featured researches published by Hiroo Ohnishi.


Nutrition | 2002

Prognostic Value of Energy Metabolism in Patients With Viral Liver Cirrhosis

Masahiko Kato; Hiromi Mohri; Yoshiyuki Miwa; Tomohiro Kato; Hiroo Ohnishi; Hisataka Moriwaki

The effect of energy malnutrition on survival in patients with non-alcoholic viral liver cirrhosis has not been well defined. We characterized energy metabolism at study entrance and prospectively analyzed its effect on subsequent survival in cirrhotics. One hundred nine consecutive patients with viral liver cirrhosis and 22 healthy control subjects participated in the study. By indirect calorimetry after overnight bedrest and fasting, resting energy expenditure (REE) was measured and non-protein respiratory quotient (npRQ) was calculated. Survival of cirrhotics were followed for up to 8 y. Survival rate was estimated with the Kaplan-Meier method. REE at entrance was significantly higher than the predicted basal metabolic rate (BMR) in cirrhotics (P < 0.001). NpRQ was significantly lower in cirrhotics than in controls (P < 0.001). Survival rate was significantly lower in patients with low npRQ ( < 0.85) than in patients with scores above 0.85 (P < 0.01) and was significantly higher in normal metabolic patients (0.9 < REE/BMR < 1.1) than in hypometabolic (REE/BMR < 0.9) or hypermetabolic (1.1 < REE/BMR) patients (P < 0.05). The proportional hazards model showed that npRQ (relative risk = 0.0003, 95% confidence interval = 0.0000-0.0970), REE/BMR (0.0199, 0.0007-0.5652), prothrombin time, and ammonia were independent significant factors determining survival. Thus evaluation of energy metabolism can be used to predict survival in patients with viral liver cirrhosis.


Gastroenterology | 1994

Hepatic injury and lethal shock in galactosamine-sensitized mice induced by the superantigen staphylococcal enterotoxin B

Masahito Nagaki; Yasutoshi Muto; Hiroo Ohnishi; Shigeo Yasuda; Kimiyasu Sano; Tomoo Naito; Teruo Maeda; Tetsuya Yamada; Hisataka Moriwaki

BACKGROUND/AIMS Staphylococcal enterotoxin B (SEB) acts as a superantigen binding to class II major histocompatibility complex proteins, and this complex stimulates T cells. The aim of this study was to investigate the pathogenic effects of SEB on hepatic injury and lethal shock in mice. METHODS SEB was administered to D-galactosamine (GalN)-sensitized mice, and the degree of liver injury and levels of circulating cytokines were determined. In vitro cytokine production in response to SEB was also investigated. RESULTS Intraperitoneal administration of SEB (50 micrograms) caused lethal shock (50% mortality) associated with massive hepatic necrosis in GalN-sensitized mice, with no mortality on injection of up to 100 micrograms SEB alone. Within 2 hours after injection of SEB, serum tumor necrosis factor alpha (TNF-alpha) levels reached a peak, followed by high levels of serum interferon-gamma (IFN-gamma) up to 10 hours after injection. Passive immunization with anti-TNF-alpha/beta-neutralizing monoclonal antibody (mAb) protected GalN-sensitized mice from the lethal effects of SEB, with less protection with anti-IFN-gamma-neutralizing mAb. SEB induced the production of TNF-alpha and IFN-gamma in a dose-dependent manner from splenic mononuclear cells in vitro. CONCLUSIONS The results show that SEB contributes to lethal shock associated with severe hepatic injury in GalN-sensitized mice and suggest that TNF-alpha and IFN-gamma produced in response to SEB may be mediators of the lethal toxicity and hepatotoxicity of SEB.


The Journal of Infectious Diseases | 2000

High Levels of Serum Interleukin-10 and Tumor Necrosis Factor—α Are Associated with Fatality in Fulminant Hepatitis

Masahito Nagaki; Hiroko Iwai; Takafumi Naiki; Hiroo Ohnishi; Yasutoshi Muto; Hisataka Moriwaki

Serum pro- and anti-inflammatory mediators in patients with acute liver diseases were assessed to clarify the clinical significance of these measurements in relation to disease severity. Concentrations of circulating tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, IL-6, IL-10, IL-12, and soluble TNF receptors (sTNFR) p55 and p75 were measured at admission in patients with fulminant hepatitis (FH; n=19), severe acute hepatitis (AHS, n=15), or acute hepatitis (AH, n=7). Serum concentrations of TNF-alpha, IL-10, and sTNFR-55 were significantly higher in patients with FH than in those with AHS (P<.05, <.05, and <.01, respectively) or AH (P<.05). Serum IL-10 and TNF-alpha levels were higher in patients who died of FH (n=13) than in FH survivors (n=6; P<.05). The ratios between TNF-alpha and IL-10 and sTNFR-55 or sTNFR-75 were not valuable in predicting mortality and disease severity. However, both proinflammatory cytokine TNF-alpha and anti-inflammatory cytokine IL-10 levels at admission were associated with fatal outcome among patients with FH.


Hepatology Research | 2000

Improvement of fuel metabolism by nocturnal energy supplementation in patients with liver cirrhosis.

Yoshiyuki Miwa; Makoto Shiraki; Masahiko Kato; Hiromi Mohri; Nobuo Murakami; Tomohiro Kato; Hiroo Ohnishi; Yasutoshi Muto; Hisataka Moriwaki

Aims: patients with liver cirrhosis exhibit abnormal fuel metabolism, including increased fat and decreased glucose oxidation. Such altered energy metabolism is similar to that observed after starvation and could lead to malnutrition. We therefore studied whether nocturnal energy supplementation might improve the fuel metabolism in cirrhotic patients. Methods: 12 cirrhotic patients and 14 healthy controls participated in this study. Subjects in the two groups ate isonitrogenous (1.2 g/kg/day) and isocaloric (35 kcal/day) diets for 1 week before and during the study. On day 1 of the study, indirect calorimetry was carried out in the morning after an overnight fast. The next morning, the same measurement was performed after the patients took a liquid nutrient (Ensure Liquid(R), 250 kcal) at 23:00 on day 1. Respiratory quotient (RQ), resting energy expenditure (REE), and substrate oxidation rates of glucose (% CHO), fat (% FAT) and protein were estimated from measured VO(2), VCO(2) and urinary nitrogen. Results: Significant decreases in RQ, and % CHO and a significant increase in % FAT were observed at baseline in cirrhotic patients as compared with controls. After the nocturnal energy supplementation, RQ, % CHO and % FAT in cirrhotic patients were significantly recovered, ending at levels close to normal. Conclusions: These results suggest that nocturnal energy supplementation could be useful to correct abnormal fuel metabolism and to prevent malnutrition in cirrhosis.


Journal of Virology | 2003

Lack of Tumor Necrosis Factor Alpha Induces Impaired Proliferation of Hepatitis B Virus-Specific Cytotoxic T Lymphocytes

Senji Kasahara; Kazuki Ando; Kuniaki Saito; Kenji Sekikawa; Hiroyasu Ito; Tetsuya Ishikawa; Hiroo Ohnishi; Mitsuru Seishima; Shinichi Kakumu; Hisataka Moriwaki

ABSTRACT Recent studies have shown that tumor necrosis factor alpha (TNF-α) plays critical roles in not only viral clearance but also lymphoid tissue development and stem cell differentiation. In this study, we attempted to induce hepatitis B virus (HBV)-specific cytotoxic T lymphocytes (CTLs) by immunization of TNF-α knockout (TNF-α−/−) mice with HBsAg-encoding plasmid DNA. An immunization with the HBV plasmid failed to induce CTL responses in TNF-α−/− mice, although CTLs were readily induced in wild-type mice by the same protocol. Weak CTL responses were produced in TNF-α−/− mice after two sessions of immunization with the HBV plasmid; however, TNF-α was required to maintain the responses of these CTL lines to in vitro stimulation and, even then, the responses were lost after 3 weeks. Interestingly, a limiting dilution of a CTL line showed that HBV-specific CTL clones with high specific cytotoxicity were present in TNF-α−/− mice, but these clones again failed to proliferate for more than 3 weeks. Furthermore, since exogenously added TNF-α enhanced the proliferation of a TNF-α−/− clone but suppressed that of a TNF-α+/+ clone in vitro, TNF-α also has a direct effect on the proliferation of CTLs. In conclusion, TNF-α is essential rather than important for the proliferation of HBV-specific CTLs both in vivo and in vitro and this effect is not only due to the activation of dendritic cells but is also induced by the direct effect on CTLs.


Journal of Hepatology | 1999

Interleukin-10 inhibits hepatic injury and tumor necrosis factor-α and interferon-γ mRNA expression induced by staphylococcal enterotoxin B or lipopolysaccharide in galactosamine-sensitized mice

Masahito Nagaki; Manabu Tanaka; Akihiko Sugiyama; Hiroo Ohnishi; Hisataka Moriwaki

BACKGROUND/AIMS Proinflammatory cytokines including tumor necrosis factor alpha (TNF-alpha) and interferon gamma (IFN-gamma) play a critical role in the pathogenesis of liver injury induced by lipopolysaccharide (LPS) or staphylococcal enterotoxin B (SEB) in D-galactosamine (GalN)-sensitized mice. The aim of this study was to examine the ability of interleukin-10 (IL-10), a recently characterized, highly potent anti-inflammatory mediator, to protect sensitized mice against hepatotoxicity induced by SEB or LPS. METHODS IL-10 was injected at various concentrations into BALB/c mice treated by GalN/SEB or GalN/LPS. Liver injury was assessed biochemically and histologically. Serum levels of TNF-alpha and IFN-gamma were measured and the expressions of TNF-alpha and IFN-gamma mRNA in the liver and spleen were determined by reverse-transcription polymerase chain reaction. RESULTS Treatment with IL-10 markedly reduced serum transaminase activities in a dose-dependent manner and reduced hemorrhagic liver damage in sensitized mice exposed to either toxin. IL-10 also inhibited increases in serum TNF-alpha and IFN-gamma concentrations with either toxin. Treatment with IL-10 significantly reduced TNF-alpha mRNA and IFN-gamma mRNA expression in the liver and spleen after administration of either toxin to sensitized mice. CONCLUSIONS These findings suggest that IL-10 is capable of regulating both T cell- and macrophage-mediated hepatic injury in vivo and that this cytokine might be useful in the treatment of acute liver failure.


Gastroenterologia Japonica | 1981

Augmented utilization of branched-chain amino acids by skeletal muscle in decompensated liver cirrhosis in special relation to ammonia detoxication

Masanori Hayashi; Hiroo Ohnishi; Yasuhiko Kawade; Yasutoshi Muto; Yoshiyata Takahashi

SummaryFemoral arterio-venous (A-V) differences of blood free amino acids and plasma ammonia (NH3) were simultaneously determined after an overnight fast in 16 patients with decompensated liver cirrhosis in the absence and presence of encephalopathy, as compared with those in 8 control subjects. In spite of increased releases of phenylalanine (Phe) and tyrosine (Tyr) from the peripheral tissue, releases of isoleucine (Ile) and leucine (Leu) as well as alanine (Ala) were found to be significantly reduced in decompensated liver cirrhosis, particularly in the presence of hepatic encephalopathy. Furthermore, NH3 was found to be significantly taken up by the skeletal muscle of these patients, and a positive correlation was observed between arterial NH3 level and the A-V differences of Leu, of Ile and of Ala. These findings strongly suggest that net degradation (or utilization) of branched-chain amino acids (in particular, Leu and Ile) is enhanced in the muscle for detoxication of ammonia (i.e., glutamine synthesis) by supplying the carbon skeleton and energy in cirrhosis of the liver.


Digestive Diseases and Sciences | 1998

Oral Supplementation with Branched-Chain Amino Acids Improves Survival Rate of Rats with Carbon Tetrachloride-Induced Liver Cirrhosis

Kenta Kajiwara; Masataka Okuno; Tetsuo Kobayashi; Nobuko Honma; Toshio Maki; Masahiko Kato; Hiroo Ohnishi; Yasutoshi Muto; Hisataka Moriwaki

We investigated whether supplementation withbranched-chain amino acids (BCAA) improves survival ofrats with carbon tetrachloride (CCl4)-inducedcirrhosis. Liver cirrhosis was induced in 40 maleSprague-Dawley rats by administering CCl4 for 15weeks. Twenty rats each were then assigned to thecontrol and BCAA group and fed a casein diet or aBCAA-supplemented casein diet, respectively, for anadditional 17 weeks with repeated injections of CCl4. Nosignificant difference occurred in either mean energy ornitrogen intake or in body or liver weight between thetwo groups. BCAA-supplementation significantly preserved plasma albumin concentrations (P < 0.05) andinhibited significantly the occurrence of ascites andhyperammonemia (P < 0.05). The survival rate wassignificantly higher in the BCAA group (P = 0.03), while no significant difference was found inliver histology between the groups. These resultssuggest that BCAA improved survival of rats withCCl4-induced cirrhosis by preventinghypoalbuminemia and hyperammonemia without directly reducing hepatic necrosis andfibrosis.


Digestive Diseases and Sciences | 1996

Ursodeoxycholic acid corrects defective natural killer activity by inhibiting prostaglandin E2 production in primary biliary cirrhosis

Youichi Nishigaki; Hiroo Ohnishi; Hisataka Moriwaki; Yasutoshi Muto

We evaluated the effect of ursodeoxycholic acid on the defective natural killer activity in primary biliary cirrhosis. Administration of ursodeoxycholic acid (600 mg daily) for one month significantly increased natural killer activity in patients with primary biliary cirrhosis (P<0.05). Ursodeoxycholic acid also enhanced thein vitro natural killer activity of lymphocytes from healthy volunteers, while other hydrophobic bile acids depressed it. Furthermore, ursodeoxycholic acid reduced the prostaglandin E2 concentration in culture supernatants of lymphocytes from healthy volunteers to a lower level than that in cultures incubated with chenodeoxycholic acid (P<0.05) or control cultures (P<0.01). Ursodeoxycholic acid normalized the defective natural killer activity in primary biliary cirrhosis by reducing the levels of other hydrophobic bile acids and inhibiting prostaglandin E2 production, suggesting that it may be a useful immunomodulating agent for primary biliary cirrhosis.


Gastroenterologia Japonica | 1990

Enhanced tumor necrosis factor and interleukin-1 in an experimental model of massive liver cell necrosis/fatal hepatitis in mice.

Pei Liu; Hiroo Ohnishi; Hisataka Moriwaki; Yasutoshi Muto

SummaryStudies were conducted to investigate possible roles of tumor necrosis factor (TNF) and interleukin-1 (IL-1) in liver cell necrosis/fatal hepatitis in mice which were injected withPropionibacterium acnes (P.acnes) and subsequently 7 days later with a small dose of lipopolysaccharide-endotoxin (LPS). Higher serum levels of TNF were observed in the model, and enhanced production of both TNF and IL-1 was also found in hepatic as well as splenic adherent cells that were isolated from mice pretreated withP.acnes and were stimulated by LPSin vitro. When TNF substituted for LPS in the model, fatal hepatitis was also induced within 24 hrs, although the replacement of LPS by IL-1 resulted in no lethality. Moreover, when a combination of a near non-lethal doses of TNF and IL-1 substituted for LPS, 100% lethality was observed within 4 hrs. These results strongly suggest that both TNF and IL-1 are crucial soluble factors which are released by infiltrating macrophages in both liver and spleen, and are responsible for the development of liver cell necrosis/fatal hepatitis. In particular, TNF is one of the principal mediators of liver injury and IL-1 may potentiate the lethal effect of TNF in an LPS-related experimental model of massive liver cell necrosis.

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