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T Uesugi

Publications and source records attributed to T Uesugi.

At least 19 recordsLinked to original sources

Effects of phosphodiesterase-III inhibitors on sevoflurane-induced impairment of rat diaphragmatic function.

BACKGROUND: Volatile anesthetics are known to cause diaphragmatic dysfunction using a whole body model. The first aim of the current study was to compare the impairing effect of halothane and sevoflurane on diaphragmatic contractile functions under unfatigued and fatigued conditions. The second purpose was to determine whether phosphodiesterase-III inhibitors can attenuate sevoflurane-potentiated reduction of contractility after fatigue. METHODS: Using rat-isolated muscle strips, diaphragmatic twitch characteristics and tetanic contractions were measured before and after muscle fatigue, which was induced by repetitive tetanic contraction with or without exposure to halothane (1-3 MAC) or sevoflurane (1-3 MAC). Diaphragmatic functions were further assessed with exposure to 3 MAC sevoflurane in the presence and absence of milrinone, or olprinone. Cyclic adenosine monophosphate (cAMP) concentrations in the fatigued diaphragm were also measured. RESULTS: Halothane (1-3 MAC) or sevoflurane (1-2 MAC) did not induce a direct inotropic effect under unfatigued and fatigued conditions. Sevoflurane at 3 MAC enhanced fatigue-induced impairment of twitch and tetanic tensions. Clinically relevant concentrations of olprinone improved the sevoflurane-induced potentiation of diaphragmatic dysfunction following fatigue, accompanied by restoration of diaphragmatic cAMP levels, although milrinone failed to do so. CONCLUSION: Our findings suggest that sevoflurane has a greater decreasing effect on diaphragmatic contractility after fatigue than halothane, and that the clinical dose of olprinone surmounts the disadvantage of sevoflurane in various conditions where diaphragmatic fatigue is predisposed.

3',5'-Cyclic-AMP Phosphodiesterases↗

Real-time monitoring for detecting rejection using strain gauge force transducers in porcine small bowel transplantation.

PURPOSE: The clinical results of small bowel transplantation (SBT) have not been satisfactory mainly because of the immunological barrier. It is important to detect the presence of and to perform adequate treatment of rejection as early as possible to improve graft survival. Therefore, we have established a pig model to monitor graft motility as a means to detect rejection in real time. METHODS: Orthotropic SBT was performed in 25 pigs using FK-506 (0.05 to 0.1 mg/kg/d) immunosuppression. The interdigestive motor patterns were evaluated using strain gauge force transducers (SG). Seven pigs without SBT were treated as controls (C). Animals that displayed migrating motor complex (MMC) activity as evidenced by duration, amplitude, and interval in the graft were alive more than 10 days with adequate oral feeding: the functional graft (FG) group. In contrast the rejection (R) group did not show these activities on data recorded within 10 days before death due to rejection. RESULTS: The FG group showed MMC propagated throughout the graft with all parameters almost the same as the control group except for the duration. In contrast, all parameters in the group R were significantly lower than those in group FG, suggesting that group R motility was obviously impaired by rejection. CONCLUSIONS: The SG method may afford real-time monitoring of transplanted bowel motility that could be useful to detect rejection after SBT.

Animals↗

Immunosuppressive effect of nucleoside-nucleotide-free diet in rat allogeneic small intestinal transplantation.

BACKGROUND: We evaluated the effects of nucleosides (NS) and nucleotides (NT) on the rejection of rat allogeneic small intestinal transplants. METHODS: A 2-cm segment of jejunum from fetal Fischer rats (RT-1(lvl)) was transplanted at day 19 of gestation into the abdominal wall of 7-week-old Lewis rats (RT-1(l)) by a nonvascular technique. Two weeks before transplantation, recipient rats were separated into an NS-NT-free group and an NS-NT-supplemented group. At 2 days after transplantation, histologic study of the grafts was performed with hematoxylin-eosin staining and interleukin-2 (IL-2) production estimated in recipient blood using an ELISA method. The morphologic findings were graded in a blind fashion on a scale of 0 to 4, with 0 indicating an intact intestinal structure. RESULTS: Mean plasma IL-2 levels of the NS-NT-free group were significantly lower than those of the NS-NT-supplemented group. The mean rejection score of the NS-NT-free group was also significantly lower than that of the NS-NT-supplemented group. CONCLUSIONS: Administration of an NS-NT-free diet reduces acute rejection in rat small intestinal transplantations.

Animals↗

Effects of omega-3 fatty acids in rat allogenic small intestinal transplantation.

The aim of this study was to estimate the effect of omega-3 fatty acids on the recipient and graft immune response after rat allogenic small intestinal transplantation. Seven-week-old Lewis rats were randomly assigned to one of three groups according to the diet received: an FO group (fish oil supplemented), an SB group (soy bean oil supplemented) or a control group (normal rat chow). The recipient Lewis rats were each given their respective group diet for 12 days, and then, on the 19th day of gestation, a 2 cm jejunum from the donor fetal Fischer rat was transplanted into the abdominal wall of the recipient rats using a non-vascular anastomotic technique. The recipient rats were killed on day 2 after transplantation, and the recipient plasma IL-2, IFN-gamma and IL-1 beta levels were determined. In addition, the histological findings of the graft were analyzed. The cytokine levels of the FO group were significantly lower than the other two groups. In order to determine the grade of rejection, the morphological findings were blindly graded on a scale of 0-4. The mean grade of the FO group was also significantly lower than the other two groups. Omega-3 fatty acids are therefore considered to have an immunosuppressive effect on rat allogenic small intestinal transplantation based on the recipient plasma IL-1 beta, TNF and IL-2 levels and the histological findings of the grafts.

Animals↗

The role of Kupffer cell oxidant production in early ethanol-induced liver disease.

Considerable evidence for a role of Kupffer cells in alcoholic liver disease has accumulated and they have recently been shown to be a predominant source of free radicals. Several approaches including pharmacological agents, knockout mice, and viral gene transfer have been used to fill critical gaps in understanding key mechanisms by which Kupffer cell activation, oxidant formation, and cytokine production lead to liver damage and subsequent pathogenesis. This review highlights new data in support of the hypothesis that Kupffer cells play a pivotal role in hepatotoxicity due to ethanol by producing oxidants via NADPH oxidase.

Adenoviridae↗

Metabolism of bucolome in rats. Stability and biliary excretion of bucolome N-glucuronide.

Bucolome (BCP) is a non-steroidal anti-inflammatory drug, which is used in the treatment of chronic articular rheumatism. Bucolome N-glucuronide (BCP-NG), a metabolite of BCP, is the first unique N-glucuronide of barbituric acid derivatives. First, the stability of BCP-NG in various pH aqueous solutions was studied. BCP-NG was quite unstable under neutral and acidic conditions, and is easily hydrolyzed to BCP. Based on these characteristics of BCP-NG, a simple, rapid and highly sensitive method for the simultaneous determination of BCP and BCP-NG with phenylbutazone (I.S.) in biological fluids was developed using high-performance liquid chromatography (HPLC). A reversed-phase ODS column was used for the separation of BCP, BCP-NG and I.S. A pharmacokinetic study for BCP and BCP-NG was carried out in male Wistar/ST rats following i.v. administration of BCP at a dose of 10 mg/kg body weight. The slow plasma elimination of BCP with time was shown. A major metabolite of BCP in bile was N-glucuronide. The cumulative amounts of BCP and BCP-NG in the bile over 8 h were approximately 2.4 +/- 1.4% and 12.6 +/- 2.3% of the dose, respectively. BCP and BCP-NG in the urine were 2.7 +/- 0.7% and 3.2 +/- 0.3% of the dose. Although BCP had a long half-life (over 8.5 h), the preliminary pharmacokinetic parameters (0-8 h) were determined: t 1/2, 8.52 +/- 1.96 h; AUC, 419.9 +/- 45.2 microg x h/ml; MRT, 3.29 +/- 0.11 h; CLtot, 5.93 +/- 0.54 ml/h; and Vdss, 19.5 +/- 1.3 l. These observations are the first pharmacokinetic findings for the N-glucuronide of the barbituric acid derivatives.

Animals↗

Overexpression of manganese superoxide dismutase prevents alcohol-induced liver injury in the rat.

Mitochondria are thought to play a major role in hepatic oxidative stress associated with alcohol-induced liver injury. Thus, the hypothesis that delivery of the mitochondrial isoform of superoxide dismutase (Mn-SOD) via recombinant adenovirus would reduce alcohol-induced liver injury was tested. Rats were given recombinant adenovirus containing Mn-SOD (Ad.SOD2) or beta-galactosidase (Ad.lacZ) and then fed alcohol enterally for 4 weeks. Mn-SOD expression and activity of Ad.SOD2 in liver mitochondria of infected animals was increased nearly 3-fold compared with Ad.lacZ-infected controls. Mitochondrial glutathione levels in Ad.lacZ-infected animals were decreased after 4 weeks of chronic ethanol, as expected, but were unchanged in Ad.SOD2-infected animals. Alanine aminotransferase was elevated significantly by ethanol, an effect that was prevented by Ad.SOD2. Moreover, pathology (e.g. the sum of steatosis, inflammation, and necrosis) was elevated dramatically by ethanol in Ad.lacZ-treated rats. This effect was also blunted in animals infected with Ad.SOD2. Neutrophil infiltration was increased about 3-fold in livers from both Ad.lacZ- and Ad.SOD2-infected rats by ethanol treatment. Moreover, ESR-detectable free radical adducts in bile were increased about 8-fold by ethanol. Using (13)C-labeled ethanol, it was determined that nearly 60% of total adducts were due to the alpha-hydroxyethyl radical adduct. This increase in radical formation was blocked completely by Ad.SOD2 infection. Furthermore, apoptosis of hepatocytes was increased about 5-fold by ethanol, an effect also blocked by Ad.SOD2. Interestingly, tumor necrosis factor-alpha mRNA was elevated to the same extent in both Ad.lacZ- and Ad.SOD2-infected animals follows ethanol exposure. These data suggest that hepatocyte mitochondrial oxidative stress is involved in alcohol-induced liver damage and likely follows Kupffer cell activation, cytokine production, and neutrophil infiltration. These results also support the hypothesis that mitochondrial oxidant production is a critical factor in parenchymal cell death caused by alcohol.

Adenoviridae↗

Reduced early alcohol-induced liver injury in CD14-deficient mice.

Activation of Kupffer cells by gut-derived endotoxin is associated with alcohol-induced liver injury. Recently, it was shown that CD14-deficient mice are more resistant to endotoxin-induced shock than wild-type controls. Therefore, this study was designed to investigate the role of CD14 receptors in early alcohol-induced liver injury using CD14 knockout and wild-type BALB/c mice in a model of enteral ethanol delivery. Animals were given a high-fat liquid diet continuously with ethanol or isocaloric maltose-dextrin as control for 4 wk. The liver to body weight ratio in wild-type mice (5.8 +/- 0.3%) was increased significantly by ethanol (7.3 +/- 0.2%) but was not altered by ethanol in CD14-deficient mice. Ethanol elevated serum alanine aminotransferase levels nearly 3-fold in wild-type mice, but not in CD14-deficient mice. Wild-type and knockout mice given the control high-fat diet had normal liver histology, whereas ethanol caused severe liver injury (steatosis, inflammation, and necrosis; pathology score = 3.8 +/- 0.4). In contrast, CD14-deficient mice given ethanol showed minimal hepatic changes (score = 1.6 +/- 0.3, p < 0.05). Additionally, NF-kappa B, TGF-beta, and TNF-alpha were increased significantly in wild-type mice fed ethanol but not in the CD14 knockout. Thus, chronic ethanol feeding caused more severe liver injury in wild-type than CD14 knockouts, supporting the hypothesis that endotoxin acting via CD14 plays a major role in the development of early alcohol-induced liver injury.

Acute-Phase Proteins↗

Influence of humoral immunoreaction on hepatic nonparenchymal cells in ex situ xenoperfused rat livers.

BACKGROUND: The influence of xenogeneic humoral immunoreaction on hepatic nonparenchymal cells (NPCs) was evaluated ex situ in xenoperfused rat livers. METHODS: Isolated rat livers were perfused via the portal vein (PV) for 240 min. The perfusates consisted of fresh rat blood (group 1), fresh human blood (group 2), and fresh human blood containing 5 microg/mL soluble complement receptor type 1 (Group 3). RESULTS: Deposition of human IgM and C(5b-9) complement was observed in group 2, although only human IgM deposition was detected in group 3. Portal vein pressure in group 2 rose drastically during the first 10 min. Creatine kinase BB component gradually increased in all groups, followed by an elevation in alanine aminotransferase and both parameters were significantly higher in group 2 than in groups 1 and 3. In group 2, platelet thrombi in the peripheral PVs and periportal hemorrhage were observed after 10 min, and massive necrosis around the central veins after 240 min; these changes were not observed in group 1 or 3. Production of tumor necrosis factor alpha and alpha interferon and expression of intercellular adhesion molecule 1 (ICAM-1) were lower in group 2 than in groups 1 and 3. In group 2, there were negative areas for ICAM-1 and tumor necrosis factor alpha staining around the central veins after 240 min, which were consistent with necrotic areas. CONCLUSIONS: In xenoperfused rat livers, humoral mediators initially caused the disturbance of microcirculation, which would induce long ischemia in the pericentral areas, resulting in massive necrosis. NPC necrosis may be responsible for less production of cytokines and adhesion molecules in the xenoperfused livers.

Alanine Transaminase↗

Attenuating effect of a semipurified alcohol extract of soy protein on glomerular injury in spontaneous hypercholesterolemic male Imai rats.

We investigated whether soy protein's alcohol-extractable components (SPEs; mainly consisting of isoflavones) have the ability to attenuate glomerular injury in male Imai rats of a spontaneous focal segmental glomerulosclerosis model. Male Imai rats were fed a casein-based diet with and without SPEs. Group 1 (Cont) was fed a standard diet without additional SPEs, and groups 2 (SPE-1) and 3 (SPE-2) were fed a standard diet supplemented with a semipurified alcohol extract of soy protein, 0.05 and 0.10 g/100 g of diet, respectively. Body weight, urinary protein level, serum constituents, and systolic blood pressure were evaluated every 4 weeks from 12 through 28 weeks of age. At 28 weeks of age, rats were studied morphologically. Growth rates were not different among the three groups throughout the experiment. SPE-supplemented diets resulted in less proteinuria and less hyperlipidemia. The decline in renal function shown by blood urea nitrogen and creatinine clearance was less marked in the animals fed the SPE-supplemented diets. Each SPE-supplemented diet equally induced less glomerular hypertrophy and less renal histological damage compared with nonsupplemented diets. The present study showed a beneficial effect of a semipurified alcohol extract of soy protein on glomerular disease.

Animals↗

Toll-like receptor 4 is involved in the mechanism of early alcohol-induced liver injury in mice.

Chronic alcohol administration increases gut-derived endotoxin in the portal blood, which activates Kupffer cells and causes liver injury. Mice (C3H/HeJ) with mutations in toll-like receptor 4 (TLR4) are hyporesponsive to endotoxin. To test the hypothesis that TLR4 is involved in early alcohol-induced liver injury, the long-term intragastric ethanol feeding protocol developed by Tsukamoto and French for rats was adapted to mice. Animals with nonfunctional TLR4 and wild-type mice (C3H/HeOuJ) were compared. Two-month-old female mice were fed a high-fat liquid diet with either ethanol or isocaloric maltose-dextrin as control continuously for 4 weeks. There was no difference in mean urine alcohol concentrations between the groups. Dietary alcohol significantly increased liver-to-body weight ratios and serum alanine transaminase (ALT) levels in wild-type mice (109 +/- 18 U/L) over high-fat controls (40 +/- 3 U/L), effects that were blunted significantly in mice with a mutation of TLR4 (55 +/- 9 U/L). While no significant pathologic changes were observed in high-fat controls, dietary ethanol caused steatosis, mild inflammation, and focal necrosis in wild-type animals (pathology score = 5.2 +/- 1.2). These pathologic changes were significantly lower in TLR4-deficient mice fed ethanol (score = 2.0 +/- 1.3). Endotoxin levels in the portal vein were increased significantly after 4 weeks in both groups fed ethanol. Moreover, ethanol increased tumor necrosis factor alpha (TNF-alpha) mRNA expression in wild-type, but not in TLR4-deficient, mice. These data are consistent with the hypothesis that Kupffer cell activation by endotoxin via TLR4 is involved in early alcohol-induced liver injury.

Alanine Transaminase↗

Delivery of IkappaB superrepressor gene with adenovirus reduces early alcohol-induced liver injury in rats.

Chronic alcohol administration increases gut-derived endotoxin in the portal blood, which activates Kupffer cells through nuclear factor kappaB (NF-kappaB) to produce toxic mediators such as proinflammatory cytokines, leading to liver injury. Therefore, a long-term intragastric ethanol feeding protocol was used here to test the hypothesis that NF-kappaB inhibition would prevent early alcohol-induced liver injury. Adenoviral vectors encoding either the transgene for IkappaB superrepressor (AdIkappaB-SR) or the bacterial beta-galactosidase reporter gene (AdlacZ) were administered intravenously to Wistar rats. Animals were fed a high-fat liquid diet with either ethanol or isocaloric maltose-dextrin (control) for 3 weeks. There was no significant difference in mean urine alcohol concentrations between the groups fed ethanol. IkappaB-SR expression was increased for up to 2 weeks after injection, but was undetectable at 3 weeks. NF-kappaB activation was increased by ethanol and associated with up-regulation of tumor necrosis factor alpha (TNF-alpha). These increases were blunted significantly up to 2 weeks by AdIkappaB-SR. Dietary alcohol significantly increased liver to body weight ratios and serum alanine transaminase (ALT) levels in AdlacZ-treated animals, effects that were blunted significantly in AdIkappaB-SR-treated rats. Ethanol caused severe steatosis, inflammation, and focal necrosis in AdlacZ-treated animals. These pathologic changes were significantly decreased by AdIkappaB-SR. The protective effects of IkappaB-SR were significant 2 weeks after injection, but were lost at 3 weeks when IkappaB-SR was no longer expressed. Ethanol increased 4-hydroxynonenal as a maker of oxidative stress in both AdlacZ and AdIkappaB groups. These data support the hypothesis that NF-kappaB inhibition prevents early alcohol-induced liver injury even in the presence of oxidative stress.

Adenoviridae↗

Effects of prostaglandin E(1) on the efficacy of xenogeneic extracorporeal pig liver perfusion in a canine model of acute liver failure.

Xenogeneic extracorporeal liver perfusion (ECLP) has the potential to become an important tool in the management of patients with severe liver failure. We previously showed that xenogeneic pig liver perfusion may be prolonged for up to 9 hours by the administration of prostaglandin E(1) (PGE(1)). In this study, we used a canine model of acute liver failure to evaluate the effects of PGE(1) on the efficacy of ECLP as a liver-assist device. Liver failure was surgically induced in 12 beagle dogs, with a control group (group 1, n = 4) not connected to the ECLP circuit. Direct cross-circulation between the dogs and the ECLP circuit using a pig liver was performed without (group 2, n = 4) or with (group 3, n = 4) continuous administration of PGE(1) through the portal vein of the pig liver. The duration of cross-circulation in group 3 (9.4 +/- 1.2 hours) was significantly longer than in group 2 (4.3 +/- 1.0 hours). In addition, elevation of blood ammonia, total bile acid, and hyaluronic acid levels was less marked in group 3 compared with the other 2 groups. The ratio of branched-chain amino acids to aromatic amino acids was also improved in group 3. The mean survival time in group 3 (26.6 +/- 0.4 hours) was significantly longer than in group 1 (15.5 +/- 1.3 hours) or group 2 (17.1 +/- 2.9 hours). Continuous administration of PGE(1) to xenogeneic ECLP resulted in a significant improvement in both liver function and survival time of dogs with surgically induced liver failure.

Alprostadil↗

Influence of extracorporeal porcine liver perfusion on nonhuman primates: minimizing hemolysis improves subsequent survival.

The aim of this study is to detect and analyze risk factors of direct cross-circulation between porcine liver and nonhuman primates before a clinical application of extracorporeal liver perfusion (ECLP) as a liver-assist method. Porcine livers were perfused with baboon blood in an ECLP system. Six healthy baboons were directly connected to the ECLP system with continuous prostaglandin E(1) administration. Cross-circulation was terminated in the following circumstances: (1) hepatic arterial or portal perfusion pressures elevated to 200 or 60 mm Hg, respectively; (2) massive exudative bleeding from the graft surface; or (3) bile output decreased to less than 5 microL/h/g of liver weight. In case 1, cross-circulation was continued for 10 hours. Severe macroscopic hemolysis occurred, and serum hemoglobin (s-Hb) concentration reached a peak of 47 mg/dL. The baboon died of acute renal failure 2 days later. Histological study of the perfused porcine liver showed marked microthrombi formation. In 3 of the later 5 cases, cross-circulation was discontinued when mild macroscopic hemolysis was observed. The duration of the 5 cross-circulations was maximally 6 hours (mean, 4.4 +/- 1.2 [SD] hours). Mean s-Hb concentration in the 5 cases was elevated to 14.8 +/- 5.8 mg/dL at the end of cross-circulation and decreased to the baseline level within 24 hours. These 5 baboons survived without organ dysfunction or immunologic disturbance. When severe hemolysis is avoided, direct cross-circulation using the ECLP system can be achieved without serious complications in nonhuman primates.

Animals↗

Diphenyleneiodonium sulfate, an NADPH oxidase inhibitor, prevents early alcohol-induced liver injury in the rat.

The oxidant source in alcohol-induced liver disease remains unclear. NADPH oxidase (mainly in liver Kupffer cells and infiltrating neutrophils) could be a potential free radical source. We aimed to determine if NADPH oxidase inhibitor diphenyleneiodonium sulfate (DPI) affects nuclear factor-kappaB (NF-kappaB) activation, liver tumor necrosis factor-alpha (TNF-alpha) mRNA expression, and early alcohol-induced liver injury in rats. Male Wistar rats were fed high-fat liquid diets with or without ethanol (10-16 g. kg(-1). day(-1)) continuously for up to 4 wk, using the Tsukamoto-French intragastric enteral feeding protocol. DPI or saline vehicle was administered by subcutaneous injection for 4 wk. Mean urine ethanol concentrations were similar between the ethanol- and ethanol plus DPI-treated groups. Enteral ethanol feeding caused severe fat accumulation, mild inflammation, and necrosis in the liver (pathology score, 4.3 +/- 0.3). In contrast, DPI significantly blunted these changes (pathology score, 0.8 +/- 0.4). Enteral ethanol administration for 4 wk also significantly increased free radical adduct formation, NF-kappaB activity, and TNF-alpha expression in the liver. DPI almost completely blunted these parameters. These results indicate that DPI prevents early alcohol-induced liver injury, most likely by inhibiting free radical formation via NADPH oxidase, thereby preventing NF-kappaB activation and TNF-alpha mRNA expression in the liver.

Animals↗

ICAM-1 is involved in the mechanism of alcohol-induced liver injury: studies with knockout mice.

To test the hypothesis that leukocyte infiltration mediated by intercellular adhesion molecule (ICAM)-1 is involved in early alcohol-induced liver injury, male wild-type or ICAM-1 knockout mice were fed a high-fat liquid diet with either ethanol or isocaloric maltose-dextrin for 4 wk. There were no differences in mean urine alcohol concentrations between the groups fed ethanol. Alcohol administration significantly increased liver size and serum alanine aminotransferase levels in wild-type mice over high-fat controls, effects that were blunted significantly in ICAM-1 knockout mice. Dietary ethanol caused severe steatosis, mild inflammation, and focal necrosis in livers from wild-type mice. Furthermore, livers from wild-type mice fed ethanol showed significant increases in the number of infiltrating leukocytes, which were predominantly lymphocytes. These pathological changes were blunted significantly in ICAM-1 knockout mice. Tumor necrosis factor (TNF)-alpha mRNA expression was increased in wild-type mice fed ethanol but not in ICAM-1 knockout mice. These data demonstrate that ICAM-1 and infiltrating leukocytes play important roles in early alcohol-induced liver injury, most likely by mechanisms involving TNF-alpha.

Alanine Transaminase↗