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M Washida

Publications and source records attributed to M Washida.

17 recordsLinked to original sources
PubMed2001

Spacer-mediated display of active lipase on the yeast cell surface.

We have constructed a Saccharomyces cerevisiae strain displaying an active lipase on the cell surface by cell surface engineering. The gene encoding Rhizopus oryzae lipase (ROL) was fused with the genes encoding the pre-alpha-factor leader sequence and the C-terminal half of alpha-agglutinin including the glycosylphosphatidylinositol-anchor attachment signal. The constructed gene was overexpressed under the control of the glyceraldehyde-3-phosphate dehydrogenase promoter. Linker peptides (spacers) consisting of the Gly/Ser repeat sequence were inserted at the C-terminal portion of ROL to enhance lipase activity by preserving the conformation of the active site near the C-terminal portion. Localization of the expressed ROL on the cell surface was confirmed by immunofluorescence microscopy. The ROL displayed on the yeast cell wall exhibited activity toward soluble 2,3-dimercaptopropan-1-ol tributyl ester (BALB) and insoluble triolein. The insertion of linker peptides effected the activity towards BALB, thereby demonstrating that the optimal length of linker peptides was present. The activity towards triolein was higher in lipases with longer linker peptides. ROL displayed on the cell wall exhibited a comparable and/or higher activity towards triolein than the secreted form of the enzyme. This is the first report of an active lipase displayed on the cell surface. Furthermore, insertion of a linker peptide of the appropriate length as a spacer may be an improved method to effectively display enzymes, especially those having the active region at the C-terminal portion, on the cell surface.

Agglutinins↗
PubMed1998

Gallstone ileus with impaction at the neck of a Meckel's diverticulum.

We report a case of gallstone ileus in which the stone impacted at the neck of a Meckel's diverticulum. CT demonstrated the gallstone as a calcified mass in the lower abdomen. Gallstone ileus was diagnosed although a more accurate diagnosis was not obtained pre-operatively. The site of impaction was not typical and a blind loop filled with contrast materials was evident. We believe that this is the first report demonstrating this rare condition with imaging.

Aged↗
PubMed1997

Involvement of caspase-4(-like) protease in Fas-mediated apoptotic pathway.

Proteases of the caspase family, especially caspase-1 (ICE)(-like), caspase-3 (CPP32/Yama/apopain)(-like) and caspase-8 (MACH/FLICE/Mch5) proteases, are implicated in Fas (APO-1/CD95)-mediated apoptosis. Here, we show that the caspase-4 (TX/ICH-2/ICE(rel)II)(-like) protease, another member of the caspase family, is also involved in Fas-mediated apoptosis, based upon the observations: (i) caspase-4 is processed in response to an agonistic anti-Fas antibody treatment, (ii) overexpression of a mutant caspase-4 with active site mutations in both p20 and p10 subunits delays Fas-mediated apoptosis, (iii) microinjected anti-caspase-4 antibodies inhibit Fas-mediated apoptosis. Together with our observations that the mutant caspase-4 inhibits the Fas-mediated activation of caspase-3(-like) proteases and purified caspase-4 cleaves pro-caspase-3 to generate a subunit of active form, these results suggest that Fas-mediated apoptosis is driven by a caspase cascade in which the caspase-4(-like) protease transmits a death signal from caspase-8 to caspase-3(-like) proteases probably through directly cleaving pro-caspase-3(-like) proteases.

Antibodies↗
PubMed1993

Arterial ketone body ratio as a predictor of donor liver viability in human liver transplantation.

The viability of the donor liver was assessed with regard to early postoperative survival in human liver transplantations from 40 brain-dead donors at Hannover Medical College and 13 living donors at Kyoto University by measuring the arterial ketone body ratio (AKBR). Of 40 grafts harvested from brain-dead patients in Hannover, 35 survived the first week after operation, but 5 developed initial nonfunction of the transplanted graft within the first week. The mean AKBR values were 1.11 +/- 0.11 for grafts that survived and 0.44 +/- 0.10 for grafts that failed (P < 0.01). The AKBR values of the 5 initially nonfunctioning cases were all below 0.7. Of 13 grafts harvested from the living donors in Kyoto, all survived the first week. The AKBR values of the donors were all above 1.0, with a mean value of 1.87 +/- 0.23. Among all 53 cases, the survival rate of the grafts with AKBR above 0.7 was significantly higher than that of the grafts with AKBR below 0.7 (100% vs. 62%, P < 0.01). No other donor parameters, including age, dose of dopamine administered, and clinical laboratory findings, were significantly related to differences in graft survival rates. AKBR is a useful index for the evaluation of donor liver viability. Grafts used from donors with AKBR of less than 0.7 have a significantly increased risk of early nonfunction. Grafts from donors with AKBR of greater than 1.0 have, in our experience, always been viable after transplantation.

Adult↗
PubMed1993

Effects of triiodothyronine on canine hepatic ischemia caused by Pringle's maneuver.

BACKGROUND: A significant reduction in the serum concentration of triiodothyronine is frequently observed in surgical stress and may influence the severity and prognosis of the underlying disease. METHODS: Alterations of thyroid hormone levels and effects of triiodothyronine were evaluated in the shock state after Pringle's maneuver for 60 minutes in dogs. Triiodothyronine (1 micrograms/kg/hr) was infused intravenously for 3 hours after declamping in the triiodothyronine-treated group. The effect of triiodothyronine on hepatic mitochondrial function was investigated by measuring the arterial ketone body ratio (AKBR). RESULTS: In the control group (n = 6) the low triiodothyronine syndrome was observed and progressive deterioration of AKBR and standard liver functions represented by aspartate aminotransferase, glutamic-pyruvic transaminase, and lactic dehydrogenase were noted after declamping. All dogs went into shock and died within 24 hours. By contrast, in the triiodothyronine-treated group (n = 6), hemodynamics were stabilized and standard liver functions were maintained favorably (p < 0.01). AKBR was fully restored to the preischemic liver within 30 minutes after declamping, with a decrease in serum lactate levels (p < 0.05). All dogs survived at least 7 days after operation (p < 0.01). CONCLUSIONS: These results indicate that triiodothyronine has beneficial effects on cytoprotection, hemodynamics, and hepatic energy metabolism in the ischemic liver injury. Furthermore, it improves survival in the shock state after Pringle's maneuver.

Animals↗
PubMed1992

A prolongation of hepatic vascular exclusion by in situ hypothermic perfusion in dogs.

In situ hypothermic hepatic perfusion was performed in dogs to explore whether the time limit of hepatic vascular exclusion could be prolonged. During hepatic vascular exclusion, hepatic hypothermic perfusion was performed via portal vein using various perfusates under active bypass from the portal vein and infrahepatic inferior vena cava area to the superior vena cava system. Dogs receiving hepatic hypothermic perfusion for 1 hour died when given Ringer's solution but survived more than 7 days when given Euro-Collins' and University of Wisconsin solutions. Although dogs tolerated 2 hours of hepatic hypothermic perfusion when give University of Wisconsin solution, all dogs died by 2 hours of hepatic hypothermic perfusion when given Euro-Collins' solution. The hepatic energy charge and arterial ketone body ratio of dogs that died were significantly lower than for those that survived. This suggests that the regimen of hepatic hypothermic perfusion with University of Wisconsin solution is able to maintain the energy metabolism of the liver under hepatic vascular exclusion for prolonged periods, hence, its possible clinical application.

Adenosine↗
PubMed1992

Maintenance of liver graft viability in the state of brain death. Synergistic effects of vasopressin and epinephrine on hepatic energy metabolism in brain-dead dogs.

The influence of vasopressin and epinephrine on hepatic energy metabolism in the state of brain death was assessed by measuring arterial ketone body ratio (AKBR) and hepatic energy charge (EC) in brain-dead dogs. Mean arterial blood pressure (MABP) was significantly decreased from 125.5 +/- 5.5 to 53.4 +/- 1.7 mmHg after complete brain death (P less than 0.01). In the control group AKBR and EC were maintained at near the normal values thereafter, despite marked hypotension. Combined administration of vasopressin and epinephrine sustained AKBR normally and improved MABP above 90 mmHg (P less than 0.01). EC was also maintained within the normal range at 5 hr after initiation of administration of the drugs. By contrast, vasopressin or epinephrine alone maintained AKBR and EC at near the normal values, but improved MABP just slightly to around 60 mmHg (P less than 0.01). As for the volume control, the urinary output was significantly smaller in the vasopressin and epinephrine-treated group than in the control group (P less than 0.05). It is suggested that combined administration of vasopressin and epinephrine has a synergistic effect in improving the hemodynamics and maintenance of the energy status of the liver. This regimen is recommended as a good one for maintaining potential liver donors in the state of brain death.

Adenine Nucleotides↗
PubMed1992

Beneficial effect of combined 3,5,3'-triiodothyronine and vasopressin administration of hepatic energy status and systemic hemodynamics after brain death.

The influence of combined replenishment of L-3,5,3'-triiodothyronine (T3) and vasopressin (antidiuretic hormone [ADH]) on both hepatic metabolism and systemic hemodynamics was assessed in brain-dead dogs. Arterial ketone body ratio (AKBR) was measured as a parameter of hepatic metabolism, which reflects the redox state (free nicotinamide adenine dinucleotide/reduced nicotinamide adenine dinucleotide) of liver mitochondria. Mean arterial blood pressure (MAP) was significantly decreased from 110.4 +/- 3.8 to 44.4 +/- 1.7 mmHg, at 1 hr after completion of brain death (P less than 0.01). In the control group AKBR was maintained thereafter at near control value of 1.0 with a significant decrease in serum lactate concentration in spite of marked hypotension. T3 infusion at a rate of 1 microgram/kg/hr elevated the AKBR but did not elevate MAP. Vasopressin infusion at a rate of 0.1 U/kg/hr sustained AKBR and elevated MAP significantly at 1 hr after administration but tended to decrease thereafter. Combined administration of T3 and ADH elevated the AKBR to about 2.0, and MAP was restored to near-normal level. Other parameters such as glutamic oxaloacetic transaminase, glutamic pyruvic transaminase, and lactic dehydrogenase, reflecting liver cell injury and serum creatinine, and blood urea nitrogen as renal function, were maintained within normal range. These results indicate that combined T3 and vasopressin administration has a beneficial synergistic effect on both hepatic energy metabolism and systemic hemodynamics without any detrimental influence to other conventional parameters. Therefore, it is suggested that this combined administration may contribute to the management of potential multiorgan donors.

Animals↗
PubMed1991

Hepatic energy status in hypotension of different aetiologies in dogs.

1. The alterations in hepatic energy metabolism in hypotension induced by the administration of trimetaphan camsylate (Arfonad) were investigated in comparison with those produced by hypotension resulting from massive haemorrhage by measuring the arterial ketone body ratio, which reflects the hepatic mitochondrial redox state, and other indices of hepatic energy metabolism together with simultaneous measurement of hepatic blood flow in dogs. 2. Mean arterial blood pressure was decreased from 130 mmHg to 60 mmHg by the continuous intravenous infusion of trimetaphan camsylate or by the use of Wiggers' shock model. In hypotension induced by trimetaphan camsylate, the arterial ketone body ratio, ATP and total adenine nucleotide concentrations and energy charge were maintained at near-control values throughout the experimental period. By contrast, the arterial ketone body ratio decreased from 1.04 +/- 0.09 to 0.29 +/- 0.06 at 3 h after haemorrhage in Wiggers' shock model (P less than 0.01). The ATP and total adenine nucleotide concentrations and energy charge also decreased significantly in this model (P less than 0.05). The difference in hepatic energy status was also shown by data from 31P nuclear magnetic resonance spectroscopy. 3. During hypotension, portal venous and total hepatic blood flows diminished significantly compared with the control values in each group (P less than 0.01). Although there was no significant difference in total hepatic flow between the two groups, the portal venous blood flow in hypotension induced by trimetaphan camsylate was significantly higher than that in Wiggers' shock model (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗
PubMed1991

Energy metabolism of porcine liver during a 72-hour hypothermic perfusion with UW solution.

Porcine livers were preserved for 72 h using continuous hypothermic perfusion with UW solution and fluorocarbon emulsion (FC-43). They were then recirculated with human blood for 2 h at 37 degrees C for the evaluation of their viability. During hypothermic perfusion and recirculation, the main metabolites of the perfusate and adenine nucleotide concentrations were measured in order to examine the energy metabolism of the livers. This study revealed that hypothermically perfused livers, which mainly utilize endogenous fatty acids as an energy substrate during this time were adequately preserved for 72 h. In terms of energy metabolism, it is suggested that when using the method of continuous hypothermic perfusion with UW solution and FC-43, the administration of adequate amounts of certain fatty acids might prolong the preservation period.

Adenine Nucleotides↗
PubMed1991

Hepatic vascular exclusion as a model for complete and stable hepatic ischemia in dogs.

In order to confirm a complete ischemia model, 1-hour warm hepatic ischemia by hepatic vascular exclusion (HVE) was studied in dogs, in comparison with that by inflow occlusion (IOC) only. The splanchnic venous bed and/or infrahepatic inferior vena cava were decompressed by a centripetal pump-driven venovenous bypass. Indocyanine green retention test revealed no hepatic blood flow in the HVE model during ischemia, while hepatic blood perfusion was still present in the IOC model. All 5 of the IOC dogs survived more than 7 days after revascularization, while 4 of the 5 HVE dogs died within 9 h. After the induction of hepatic ischemia, lactate increased in both HVE and IOC dogs. After revascularization, transaminases and guanase were elevated, the arterial ketone body ratio (acetoacetate/3-hydroxybutyrate) decreased and the serum lactate accumulated more in HVE dogs than in IOC dogs. The hepatic redox state of IOC dogs was significantly decreased by additional clamping of the inferior vena cava. It is concluded that the HVE model with a pump-driven active bypass provides complete and stable hepatic ischemia, resulting in greater deterioration of hepatic cellular functions; hence it is more suitable as a model of complete hepatic ischemia than the IOC one.

Animals↗
PubMedDate not supplied

Liver resection for hepatocellular carcinoma (HCC) with direct removal of tumor thrombi in the main portal vein.

Since the tumor thrombus in the main portal vein appears in the terminal stage of hepatocellular carcinoma (HCC), any attempt to remove it surgically is thought to be impractical as the malignancy itself cannot be entirely removed. During the past 5 years, we have performed tumor thrombectomy combined with hepatectomy in 29 of 298 patients with HCC. This combined therapy was initially decided upon as an emergency measure to prevent impending rupture of esophageal varices, rather than to improve patient survival. Since portal flow was obtained after removal of thrombi, this condition enabled transcatheter arterial embolization (TAE) and/or percutaneous ethanol injection therapy (PEIT). Although improved patient survival was not the primary goal of the emergency operation and there was an operative mortality of 11%, half of the other patients in the present series had unexpectedly high survival rates of 1 year (52.2%), 2 years (23.2%), and 3 years (11.6%), which were significantly higher than in patients not undergoing operation (n = 22).

Aged↗