Generalized scaling laws of the formation and effects of plasma-confining potentials for tandem-mirror operations in GAMMA 10

The main operations from 1979 to 2000 in the GAMMA 10 tandem-mirror, characterized in terms of the high-potential mode having kV-order plasma-confining potentials and the hot-ion mode yielding fusion neutrons with 10-20 keV bulk-ion temperatures, are summarized and generalized as a result of scalings of the formation and the effects of the potentials. The wide validity of potential-formation physics from Cohen's theory and the validity of the generalized Pastukhov's theory for the effects of thermal-barrier potentials on electron confinement are verified and consolidated through electron-energy balance.

Calibration of space-resolving VUV and soft X-ray spectrographs for plasma diagnostics

Vacuum ultraviolet (VUV) and soft X-ray measurements are important means of diagnosing impurities in magnetically confined plasmas used in fusion research. Recently, space- and time-resolving flat-field VUV (150-1050 A) and soft X-ray (20-350 A) spectrographs have been constructed by using aberration-corrected concave gratings with varied-spacing grooves which give a wide simultaneous spectral coverage on a microchannel-plate intensified detector. Calibration experiments have been performed at beamlines 11A and 11C at the Photon Factory of the High Energy Accelerator Research Organization. The relative efficiency of the VUV spectrograph has been measured for P-polarization geometry in the spectrograph. In the soft X-ray spectrograph, efficiencies have been obtained for several different points of irradiation on the grating along the groove direction and for two (S and P) polarization geometries.

New methods for semiconductor charge-diffusion-length measurements using synchrotron radiation

The extension of a new theory on the X-ray energy response of semiconductor detectors is carried out to characterize the X-ray response of a multichannel semiconductor detector fabricated on one silicon wafer. Recently, these multichannel detectors have been widely utilized for position-sensitive observations in various research fields, including synchrotron radiation research and fusion-plasma investigations. This article represents the verification of the physics essentials of a proposed theory on the X-ray response of semiconductor detectors. The three-dimensional charge-diffusion effects on the adjoining detector-channel signals are experimentally demonstrated at the Photon Factory for two types of multichannel detectors. These findings are conveniently applicable for measuring diffusion lengths for industrial requirements.

Characterization and interpretation of the quantum efficiencies of multilayer semiconductor detectors using a new theory

On the basis of a new theory of semiconductor X-ray detector response, a new type of multilayer semiconductor detector was designed and developed for convenient energy analyses of intense incident X-ray flux in a cumulative-current mode. Another anticipated useful property of the developed detector is a drastic improvement in high-energy X-ray response ranging over several hundred eV. The formula for the quantum efficiency of multilayer semiconductor detectors and its physical interpretations are proposed and have been successfully verified by synchrotron radiation experiments at the Photon Factory. These detectors are useful for data analyses under strong radiation-field conditions, including fusion-plasma-emitting X-rays and energetic heavy-particle beams, without the use of high-bias applications.

[Glucose intolerance after percutaneous ethanol injection therapy (PEI) in liver cirrhosis patients with hepatocellular carcinoma]

We studied the effect of percutaneous ethanol injection therapy (PEI) on glucose tolerance in liver cirrhosis patients with hepatocellular carcinoma. All of 10 patients underwent PEI and aspiration biopsy of the tumor on separate day. Two-time oral glucose tolerance tests (OGTT), before and after PEI, were performed in all patients. There were no significant changes in blood glucose and insulin chronologically measured on aspiration biopsy and PEI. To detect changes in glucose tolerance, we compared the results of OGTT before PEI with those of OGTT after PEI. On the basis of results of OGTT before PEI, patients were classified to impaired glucose tolerance group (4) and diabetes mellitus group (6). Blood glucose at 180 minutes on OGTT after PEI showed significantly higher value than that of OGTT before PEI, but insulin response was not suppressed. From these experiments we speculate that exaggerated insulin resistance due to injected ethanol may be one of the factors influencing glucose tolerance after PEI.

Role of renal gamma-glutamyltransferase activity in hepatic utilization of exogenous glutathione

The importance of renal gamma-glutamyltransferase activity in the hepatic utilization of exogenous glutathione (GSH) was evaluated by injecting GSH (1.67 mmol/kg body wt) i.v. into bilaterally nephrectomized and sham-operated Sprague-Dawley rats in which endogenous hepatic GSH had been decreased (0.20 +/- 0.01 mumol/g liver vs 5.87 +/- 0.26 mumol/g liver in normal controls, mean +/- SD) by diethylmaleate (0.5 ml/kg body wt, i.p.). Hepatic GSH concentration 60 min after GSH administration was lower in the nephrectomized than in the sham-operated rats (0.87 +/- 0.25 mumol/g liver vs 3.08 +/- 0.81 mumol/g liver, P < 0.001), while plasma GSH concentration was higher in the former (4.61 +/- 1.07 mM vs 0.11 +/- 0.06 mM, P < 0.001). In rats with intact kidneys which had been given a gamma-glutamyltransferase inhibitor (acivicin, 25 mumol/kg body wt i.v.) prior to GSH administration, the hepatic GSH concentrations (1.11 +/- 0.49 mumol/g liver) were comparable to those obtained in the nephrectomized rats. When N-acetylcysteine (1.67 mmol/kg body wt, i.v.) was administered instead of GSH, the hepatic GSH concentrations were similar in nephrectomized and sham-operated rats (1.54 +/- 0.23 mumol/g liver vs 2.22 +/- 0.58 mumol/g liver, NS). The gamma-glutamyltransferase activity was much higher in the kidney than in the liver (4460 +/- 830 IU/kg body wt vs 14 +/- 7 IU/kg body wt). These results indicate that the kidney plays an essential role in the hepatic utilization of exogenous GSH through its high gamma-glutamyltransferase activity.

[Follow-up study of hepatic hemangiomas]

Hepatic hemangioma is the most common benign tumor of the liver, but there are a few reports on chronological changes in size of hepatic hemangioma. To elucidate natural history of hepatic hemangioma, we evaluated consecutive ultrasonograms of 27 hemangiomas in 23 patients. Underlying liver disease in these 23 patients included seven cases with chronic hepatitis, five cases with liver cirrhosis and three cases with fatty liver. The remaining eight cases showed no evidence of liver disease. Follow-up period ranged 12 to 114 months (average 44). During the follow-up, six (22.2%) hemangiomas changed in size on US, which included three lesions with increase in size, one lesion with decrease in size and two lesions with spontaneous regression. Of 12 patients with chronic liver disease, only one patient showed significant change in the hemangioma size, which regressed spontaneously. These results showed that there was no case showing increase in size of hemangioma in patients with chronic liver disease. Thus, if clinically diagnosed hemangioma which tends to increase in size is detected on US or other imaging modalities in patients with chronic liver disease, aimed aspiration biopsy should be preferably performed considering the possibility of hepatocellular carcinoma.

Bile flow in a mutant Sprague-Dawley rat with defective biliary excretion of glutathione

The Eisai hyperbilirubinemic rat is a mutant strain of Sprague-Dawley origin with hereditary defects in the biliary excretion of bilirubin glucuronide, glutathione, and several other organic anions. The correlation between bile flow and bile acid excretion rates during taurocholate infusion revealed that bile acid-independent flow was smaller in the mutant than in intact Sprague-Dawley rats (19.3 vs 56.0 microliters/kg per min), while bile acid-dependent flow was similar. The correlation between bile flow and glutathione excretion rates in Sprague-Dawley rats with modified hepatic glutathione levels revealed that a certain portion of bile flow was proportional to the biliary excretion of glutathione, with a coefficient of 551 bile per 1 mol glutathione. One-third of bile acid-independent bile flow in intact Sprague-Dawley rats was accounted for by glutathione osmosis, which feature was absent in the mutant rats.

Effects of glutathione isopropyl ester on bile flow in glutathione-depleted rats

Combined administration of buthionine sulfoximine (2.5 mmol/kg, i.p.) and diethyl maleate (1.0 ml/kg, i.p.) resulted in a near-complete depletion of hepatic glutathione (0.02 mumol/g liver vs 5.17 mumol/g in saline-treated controls) in male Sprague-Dawley rats. Bile flow was markedly reduced in the rats as compared with the controls and glutathione was not detected in the bile. The linear regression of the correlation between bile flow and endogenous bile-acid excretion rates revealed that no bile acid-independent bile flow was produced in the glutathione-depleted rats. The bile flow was partially restored by an intravenous infusion of glutathione isopropyl ester (1.17 mmol/kg/hr). Glutathione levels were increased in the bile (16 nmol/kg/min) and in the liver (0.55 mumol/g) at the end of the 100 min infusion period of the ester. The increments in bile flow rates were not proportional to the biliary excretion rates of bile acids or glutathione, and the flow rates suddenly increased when glutathione levels in the bile reached an apparent threshold. The increments, not accompanied with an excretion of diethyl maleate-glutathione conjugate, were much greater than expected from the osmotic choleresis of glutathione in the bile. These results indicate that hepatic glutathione above a certain level is required for the formation of a portion of bile flow, and that an intravenous administration of glutathione isopropyl ester is effective in partially restoring the bile formation impaired by glutathione depletion.