The effect of FK506 on warm ischemia and reperfusion injury in the rat liver

The protective effect of FK506 on hepatocytes against ischemia and reperfusion injury was examined by evaluating the following: the high energy phosphorus metabolism obtained using 31P magnetic resonance spectroscopy (31P-MRS) and the tissue blood flow of the liver in ischemia and the reperfusion process, mitochondrial glutamic oxaloacetic transaminase (m-GOT) and glutamic pyruvic transaminase (GPT), the survival rates of the animals, a histological study and immunohistological staining for intercellular adhesion molecule-1 (ICAM-1) in the liver after ischemia. The rats were treated with FK506 1 mg/kg/day i.m. for 4 days before testing. Ischemia was induced by clamping the hepatoduodenal ligament for 30 min. In 31P-MRS, the recovery of the hepatic energy status after ischemia, evaluated by beta-ATP/inorganic phosphate (Pi), was significantly better in the FK506 group. It also coincided with the recovery of tissue blood flow monitored with a laser Doppler flowmeter. In the histological examination, the congestion observed in the periportal region of the control group was mild, while there was less induction of ICAM-1 in the endothelial cells of the portal veins and hepatic veins in the FK506 group. From these findings, we concluded that FK506 had a protective effect on hepatocytes against warm ischemia and reperfusion injury, and the mechanism for this could partially be attributed to improved tissue blood flow after ischemia by the modulation of immunological events.

Basic study on hepatic resection under partial perfusion cooling

To improve liver quality after reperfusion following partial hepatectomy under total or partial cooling of the liver (HPC), a new perfusion solution containing 100 mM L-histidine (KM solution) was developed. The livers of Lewis rats were removed and perfused for 2 hours at 20 degrees C with lactated Ringer's (LR) solution (group A) or the KM solution (group B). They were reperfused with rat blood at 37 degrees C at a perfusion pressure of 5 cmH2O while monitoring the portal and peripheral tissue blood flows. At the end of reperfusion, bile production, lactate dehydrogenase (LDH) secretion, and tissue adenosine triphosphate (ATP) was measured. Recovery of portal and peripheral tissue blood flows of the group B livers after reperfusion were significantly better than those of group A. Viability of the group B livers, assessed by bile production, tissue ATP value, and LDH release, was preserved better than that of group A livers. In situ total liver perfusion with LR (group C) and KM (group D) solutions for 1 hour at 20 degrees C followed by partial hepatectomy of the left lateral lobe was performed. The 1-week survivals of the group C and D rats were 25% and 100%, respectively (p < 0.05). It was concluded that KM solution is suitable for HPC.

D-lactate metabolism in patients with chronic renal failure undergoing CAPD

To clarify the D-lactate metabolism in patients with chronic renal failure undergoing CAPD, plasma levels, loaded doses and urinary excretion of D-lactate were measured. In addition, D-2-hydroxy acid dehydrogenase activities in resected and autopsied specimens were measured. The daily loaded dose of D-lactate by CAPD was 88.9 +/- 1.29 mmol and urinary excretion was negligible. There was no tendency for the plasma D-lactate to accumulate. The enzyme activity was detected in the liver, kidney and pancreas tissues both in the resected and autopsied specimens. The above findings indicate that the loaded D-lactate is catabolized in patients with chronic renal failure undergoing CAPD, and D-2-hydroxy acid dehydrogenase is responsible for the metabolism of D-lactate in humans.

[Thrombotic thrombocytopenic purpura associated with myasthenia gravis]

A case of thrombotic thrombocytopenic purpura (TTP) associated with myasthenia gravis (MG) is reported. A 56-year-old woman was admitted to our hospital on April 27, 1988, because of easy fatigue and double vision. She was diagnosed as having myasthenia gravis from her neurological and laboratory findings. On the 14th hospital day, she developed fever, jaundice, hematuria, purpura and consciousness disturbance. Hematological examination revealed marked anemia, thrombocytopenia, fragmented red blood cells, elevated bilirubin and LDH level. Coagulation studies were almost normal. She was diagnosed as having TTP and treated with corticosteroid, antiplatelet agents and plasma exchange. Clinical condition and laboratory findings improved by the 23rd hospital day. It has been reported that TTP is associated with various autoimmune disease such as systemic lupus erythematosus, rheumatoid arthritis, Sjögren's syndrome or idiopathic thrombocytopenic purpura. However TTP associated with MG appears the first report. This case may suggest that one of pathogenesis of TTP is autoimmune mechanism.

[31P-NMR study on the high energy phosphate metabolism in warm ischemic rat liver caused by hepatic artery and portal vein occlusion]

An effect on normothermic ischemia on the rat liver metabolism was examined using in vivo 31P-NMR spectroscopy. Energy metabolism was monitored by measuring the ratio of beta-ATP/Pi and changes were compared between two groups, untreated rats (Group A) and rats of which spleens were subcutaneously transposed to perform portosystemic collaterals (Group B). In group A, beta-ATP/Pi reduced to 0.18 after occlusion of both portal vein and hepatic artery for 10 min, and recovered to 0.97 at 120 min after reperfusion was initiated. In the case of 30 minischemia, however, it recovered only to 0.53 even at 120 min after reperfusion. In contrast to group A, it recovered to 0.81 at 120 min after reperfusion following 30 min-ischemia in group B. Furthermore, when 10 min-ischemia was repeated 3 times with intervals of 10 min-perfusion in group B, it recovered to 0.87 as early as 20 min after initiation of reperfusion. These results clearly indicate that the prevention of the portal congestion improves recovery from energy metabolic disorder and, in addition, division of total ischemic time with moderate intermission is effective to diminish the metabolic disorder due to occlusion of both hepatic artery and portal vein. However without the prevention of the portal congestion the effect of division of total ischemic time was significantly reduced.

Microsomal cytochrome P-450-linked monooxygenase systems and lipid composition of human hepatocellular carcinoma

The tissues of hepatocellular carcinoma were operatively resected from six patients. All four components of the systems of microsomal cytochrome P-450-linked monooxygenase of the tissues were investigated and compared to those of normal liver tissue. The concentrations of cytochromes P-450, P-420 and b5 were measured optically and the concentrations of all components except cytochrome P-450 were measured by the Western blotting method followed by immunochemical staining. In microsomes of hepatocellular carcinoma tissues, there was as much cytochrome P-450 and other redox components as in the normal liver tissues, but cytochrome P-450 in liver cancer tissues was unstable and easily converted to cytochrome P-420. The specific activities of NADPH- and NADH-ferricyanide and cytochrome c reductase of each sample were also measured. In the microsomes of the cancer tissues, the specific activities were remarkably reduced compared with those of normal liver tissues. The lipid compositions of the microsomes and the phospholipid/cholesterol ratios (w/w) were 13.1 +/- 3.13 in the cancer tissues and 43.0 +/- 6.74 in normal liver tissues. This difference of the lipid composition elucidates the instability of cytochrome P-450 molecules and the inefficiency of the electron transport of cytochrome P-450-linked monooxygenase systems.

[An evaluation of predicting postoperative residual liver function using 99mTc tin colloid]

The rate of clearance (K value) of 99mTc tin colloid in the liver differentiates normal subjects from liver cirrhosis patients; so 99mTc tin colloid is as useful as 198Au colloid as a marker of liver function. There are several reports concerning volume estimation using liver scintigraphy. Our original method was devised to measure the effective liver volume by scintigraphy. By combining the K value with effective liver volume, a predictive index was obtained in order to predict the residual liver function before hepatic resection. The index in 24 patients with liver diseases was investigated before hepatic resection. Three of them died due to hepatic failure after hepatic resection. The indices were between 0.40 and 0.45 in two of these three patients and 0.338 in one. Among the patients without hepatic failure, the indices showed more than 0.45 in 19 patients and between 0.40 and 0.45 in two. These results indicate that the limitation of hepatic resection is between 0.40 and 0.45 of the predictive index.

[Clinical studies on the biliary excretion of mezlocillin, especially in cases with liver dysfunction]

To investigate efficacy of mezlocillin (MZPC) in the treatment of biliary tract infection, the time course concentrations of MZPC in the bile of patients with, in particular, liver dysfunction were measured. MZPC concentrations in the bile decreased with the increase in the severity of liver dysfunction. However, the bile concentration was maintained more than 50 micrograms/ml even in cases of severe cholangitis with obstructive jaundice. These results indicate that MZPC is an useful antibiotic for the treatment of biliary tract infection.

Calcium-binding of cardiac sarcoplasmic reticulum and diastolic hemodynamics in volume overloaded canine hearts

The relationship between the active Ca2+-binding function of the cardiac sarcoplasmic reticulum (SR) and left ventricular (LV) relaxation was studied in various stages of chronically volume overloading canine hearts induced by complete atrio-ventricular (A-V) block. Rapid kinetic measurement of the Ca2+-binding activity of SR was made using a dual-beam spectrophotometric assay procedure. LV hemodynamics, especially diastolic indexes, were evaluated by the pressure-volume relationship using a trans-epicardial echo-cardiographic technique. In this study the maximum Ca2+-binding capacity and the initial Ca2+-binding rate of SR were impaired in eccentric hypertrophied hearts and failing hearts induced by volume overload. However, there was no significant difference of SR functional defect between the hypertrophied and the failing hearts. LV systolic properties were not influenced even by chronic volume overload. Its diastolic properties, however, were reduced with the progress of eccentric hypertrophy, and were estimated to respond more sensitively to the abnormalities of cardiac function compared with systolic properties. There was a close interrelation between the Ca2+-binding activity of SR on the molecular level and diastolic parameters, especially the time constant T, on the ventricular chamber level. In conclusion, the impairment of the Ca2+-binding activity of SR is a cause of depression of LV diastole. However, the role of SR in the occurrence of heart failure could not be clarified in this study.