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Biomedical subjects

N Ohkohchi

Publications and source records attributed to N Ohkohchi.

At least 55 records · Page 3Linked to original sources
PubMed1997

Disorder of bile acid metabolism in children with short bowel syndrome.

The profile of fecal bile acids was examined in 13 children with short bowel syndrome; 7 of the 13 did not have diarrhea and the other 6 had intractable diarrhea. In children without diarrhea, no severe fat malabsorption was recognized, and the content of total bile acids in the feces was within the normal range or slightly higher. The ratio of primary to total bile acids showed various patterns. In children with intractable diarrhea, in contrast, fat malabsorption was observed and the fecal content of total bile acids in these patients was more than ten times higher than that of the control group, primary bile acids accounting for more than 95% of the total bile acids and taurine- or glycine-conjugated bile acids for 10%. In the children with intractable diarrhea, the values for the D-xylose absorption test were lower than the normal range. These results suggested that, in children with short bowel syndrome with diarrhea, the loss of bile acids was strongly associated with a decrease in the actual absorptive surface area of the residual small intestine, and the growth of the normal bacterial flora was disturbed in the residual intestine. Some children with or without diarrhea also had hyper bile acidemia. Ursodeoxycholic acid was not effective for the treatment of hyper bile acidemia or fat malabsorption.

Adolescent↗
PubMed1997

Liver transplantation for severe hypoxemia caused by patent ductus venosus.

The authors describe the case of a 9-year-old girl who underwent liver transplantation because she suffered from severe hypoxemia caused by patent ductus venosus (PDV). Generally, severe hypoxemia (PaO2 < 50 mm Hg in room air or < 300 mm Hg in pure oxygen) is not an indication for liver transplantation because the hypoxemia may not be improved, and may lead to a fatal outcome. PDV, which is associated with mild liver dysfunction, is not an indication for liver transplantation by itself. But in our patient, most of the mesenteric venous flow directly entered the systemic circulation through the PDV just like the portosystemic shunt, and this caused the pulmonary arteriovenous shunt and hypoxemia. Thus, the authors operated on the patient in an attempt to restore her pulmonary function. Nitric oxide (10 to 20 ppm) was added to the inhaled gas to dilate the functional pulmonary capillaries and to deliver sufficient oxygen after the transplantation. Although the patient suffered various complications after the operation, the final results were excellent.

Angiography, Digital Subtraction↗
PubMed1997

Kupffer cells generate superoxide anions and modulate reperfusion injury in rat livers after cold preservation.

This study was designed to determine the source of reactive oxygen species (ROS) and whether Kupffer cells modulate the injury of perfused rat liver after cold preservation. The livers of male Lewis rats pretreated with schizophyllan glucan (SPG) (10 mg/kg, SPG group) or gadolinium chloride (5 mg/kg; Gd group) and untreated rats (control group) were preserved in University of Wisconsin solution for 0, 12, and 24 hours at 4 degrees C and then perfused for 60 minutes with oxygenated Krebs-Henseleit bicarbonate buffer. Real-time chemiluminescence (CL) of the liver during perfusion was measured using a sensitive photomultiplier, and reperfusion injury was assessed by measuring lipid peroxidation and lactate dehydrogenase release. CL intensity reached a peak within 5 minutes of reperfusion, and superoxide dismutase completely inhibited this CL in all groups. In the control group, the total CL intensity was high after 24 hours of preservation. It significantly (P < .05 vs. control group) increased in the SPG group, while it decreased in the Gd group after 12 and 24 hours of preservation. The total CL intensity decreased by 70% (when diphenyliodonium chloride (100 micromol/L; an NADPH oxidase inhibitor) was added to the perfusate before preservation of untreated rats. Lipid peroxidation and lactate dehydrogenase release significantly (P < .05) deteriorated in the SPG group, while they ameliorated in the Gd group after 24 hours of preservation. These results demonstrate that Kupffer cells primarily generate superoxide anions and modulate the organ injury in the initial phase of reperfusion after cold preservation.

Animals↗
PubMed1997

Tumor necrosis factor-induced, superoxide-mediated neutrophil accumulation in cold ischemic/reperfused rat liver.

The mechanisms of hepatic ischemia/reperfusion injury are complicated and multifactorial. This study was designed to examine superoxide generation and neutrophil accumulation in cold ischemic-reperfused rat livers after elimination of Kupffer cells and to determine the role of superoxide/tumor necrosis factor (TNF) interactions. Rat Kupffer cells were eliminated by liposome-encapsulated dichloromethylene diphosphonate injected intravenously. Livers from control and treated rats were isolated and preserved in University of Wisconsin solution (4 degrees C) for 0, 12, and 24 hours and then perfused for 60 minutes with oxygenated Krebs-Henseleit bicarbonate buffer (37 degrees C) by adding neutrophils into the perfusate. Superoxide generation was measured by using real-time chemiluminescence (CL) during perfusion, and neutrophil accumulation was assessed by measuring myeloperoxidase activity in the liver tissue. In the control livers, CL intensity markedly increased on reoxygenation, and after neutrophil infusion it increased again with a lag period of 10 minutes. Total CL intensity and myeloperoxidase activity increased with the duration of cold preservation. TNF release into the effluent perfusate was detectable only after 24 hours of preservation, and lactate dehydrogenase release was high. Elimination of Kupffer cells attenuated CL intensity and TNF and lactate dehydrogenase release and resulted in reduced myeloperoxidase activity. Electron microscopy revealed amelioration of hepatocyte swelling and endothelial cell disruption when Kupffer cells were eliminated. After 24 hours of preservation, superoxide generation was inhibited in the control livers by anti-TNF antiserum, whereas TNF release was not inhibited by superoxide dismutase. These results suggest that TNF induces superoxide generation by Kupffer cells, which mediates neutrophil accumulation and causes cellular injury in the initial phase of reperfusion.

Animals↗
PubMed1997

Living related partial liver transplantation in biliary atresia: 11 cases of experience.

Eleven children, 4 males and 7 females, with biliary atresia receiving living related liver graft were studied. The mean age was 1.8 years and the mean body weight was 10.3 kg. The donors were 4 fathers and 7 mothers. The graft was the lateral segment or left lobe. ABO blood group matching was compatible in 9 and incompatible in 2. All patients except one were crossmatch negative. Immunosuppression at induction was triple therapy (cyclosporine, azathioprine and steroid) or FK506 plus steroid. Acute rejection episodes were treated with pulse steroids. When the signs of rejection persisted despite steroid pulse therapy, 15-deoxyspergualin (DSG) was added. The survival rate of the patients was 73%. Three patients died of portal vein thrombosis, hepatic artery thrombosis and sepsis respectively. Other major complications included hyperbilirubinemia, bile duct stenosis, bile leakage and portal vein anastomosis narrowing. Complications of the donor were sepsis in one, and liver dysfunction in two. Although there are some complications related to graft size mismatch and operative procedure, living related partial liver transplantation is an effective therapy in countries where donor source is restricted.

ABO Blood-Group System↗
PubMed1997

Analysis of bilirubin fraction in the bile for early diagnosis of acute rejection in living related liver transplantation.

The diagnosis of acute rejection in liver transplantation usually needs hepatic biopsy, but hepatic biopsy sometimes involves severe complications. We analyzed biliary bilirubin fraction after living related liver transplantation by using high performance liquid chromatography (HPLC) and investigated availability for the early diagnosis of acute rejection retrospectively. Nine children with liver cirrhosis due to biliary atresia were included in this study, who underwent living related liver transplantation at The Second Department of Surgery, Tohoku University School of Medicine. Bile was collected daily from a biliary canulae inserted into the hepatic duct of the graft under aseptic and without exposure to the light. We measured the proportion of bilirubin diglucuronide (BDG), bilirubin monoglucuronide (BMG) and unconjugated bilirubin (UCB) of bile pigments in the bile by HPLC. In three of four patients with acute rejection, BDG + BMG (= Bc) was above 85% and BDG/Bc ratio was below 0.6 at the time of hepatic biopsy. After rejection therapy, BDG/Bc ratio increased in their bile. The remaining one case with acute rejection as well as bile duct injury due to arterial thrombosis of S2, Bc was below 85%, and BDG/Bc ratio was below 0.6. In four of the other five patients who had several severe complications, i.e., arterial or portal vein thrombosis, bile stasis due to cholangitis and sepsis due to necrotizing myofascitis, Bc was below 85% and BDG/Bc ratio was below 0.6. We concluded that analysis of biliary bilirubin fraction after liver transplantation could be reliable as a noninvasive maker and valuable for the early diagnosis of acute rejection.

Acute Disease↗
PubMed1997

[Development of new cell fusion technique by laser device and application to bio-medical field].

We developed a new cell fusion method which was sterile, noncontact, and selective technique under the microscope, using the micro-processing device by LASER. By this technique, we succeeded in fusing myeloma cell (SP2) and lymphocyte in mouse. We also defined the proliferation of the fused cells in HAT medium and the function of the fused cells in the Ouchterlony method, i.e. production of IgG. This method enable us to make hybridomas from very small number of cells and to fuse target cells selectively. This method is applicable to fuse cells which are difficult to be fused by conventional methods.

Animals↗
PubMed1996

Why is liver preservation performed at 4 degrees C?

To establish the most suitable temperature for liver preservation, we preserved rat livers at various temperatures (0, 5, 10, and 15 degrees C) in UW solution and investigated, biochemically, the proton ATPase activity, ATP metabolites in mitochondria, and phosphatidyl-choline hydroperoxide (PC-OOH) in liver tissue. Liver specimens were taken every 6 h up to 24 h. The proton ATPase activity and the concentration of ATP, ADP, AMP, and adenosine in livers preserved at 0 degree C showed the best results. The total adenine nucleotide (TAN) in livers preserved for 18 and 24 h had significantly higher concentrations compared with those at other temperatures (5, 10, and 15 degrees C). In the livers preserved at 5 degrees C, TAN was degraded to hypoxanthine. On the other hand, those preserved at both 10 and 15 degrees C showed changes from hypoxanthine to xanthine. The concentration of xanthine in both groups preserved at 10 and 15 degrees C showed high values at 6 and 12 h, respectively, and similar changes in PC-OOH concentrations at both 10 and 15 degrees C were observed. However, the changes in PC-OOH concentration at various temperatures were not significant for any length of preservation time. In light microscopical examinations, there were no morphological changes in the hepatocytes. From these results, we conclude that the capability of ATP synthesis of mitochondria in livers preserved at 0 degree C keep them in the best condition compared with livers preserved at 15, 10, and 5 degrees C.

Adenine Nucleotides↗
PubMed1996

Changes in the ability of ATP synthesis in the mitochondrial membrane in the rat liver injured by carbon tetrachloride.

We investigated the changes in the ability of adenosine triphosphate (ATP) synthesis in the inner mitochondrial membrane with the acute and chronic liver injuries by carbon tetrachloride (CCl4) in rats. The ability of ATP synthesis was evaluated by measuring the activity of proton ATPase and the ability of oxygen consumption using isolated mitochondria. In the acute liver injury, the ability of ATP synthesis at 6 hr after injection was preserved relatively well in spite of hepatocyte injuries. On the other hand, at 12 hr after CCl4 injection, the necrosis of hepatocyte was widely recognized. In the chronic liver injury, severe fibrosis was induced but the ability of ATP synthesis was kept as well as that in the normal liver. These results suggest that the mitochondria have some resistivity against radicals produced by CCl4.

Adenosine Triphosphate↗