Ventricular arrhythmias with left bundle branch block pattern and inferior axis: assessment of their mechanisms on the basis of response to ATP, nicorandil and verapamil.

The present study investigated the mechanism of ventricular arrhythmias showing left bundle branch block (LBBB) pattern with an inferior axis. The effects of 3 drugs, adenosine triphosphate (ATP), nicorandil and verapamil, were evaluated in 17 patients. ATP suppressed the arrhythmias in 14 patients and nicorandil suppressed them in 8 of those 14. Verapamil suppressed 5 of the 6 ATP-nicorandil-sensitive arrhythmias. Four patients with ATP- or nicorandil-sensitive arrhythmias were not sensitive to verapamil. On the other hand, 3 of the ATP-insensitive arrhythmias were sensitive to neither nicorandil nor verapamil. The QT intervals and QTc were shortened by nicorandil in 5 of the 6 patients who were sensitive to all 3 drugs. One mechanism of suppression by nicorandil could be related to less Ca++ entering the myocardium, which would decrease the duration of the action potential as indicated by the shortened QT intervals. The results suggest that the mechanism of some ventricular arrhythmias is related to triggered activity. Arrhythmias that are sensitive to ATP or nicorandil, but not to verapamil, may be caused by abnormal automaticity. On the other hand, arrhythmias that are insensitive to all 3 drugs might be related to reentry. The features of ventricular arrhythmias with LBBB pattern and inferior axis differ and therefore the causative mechanisms are not the same.

Assessment of energy status and fructose metabolism of liver in obstructive jaundice by 31P magnetic resonance spectroscopy.

The effect of cholestasis on hepatic energy status and fructose metabolism in jaundiced rats and patients was investigated using 31P magnetic resonance spectroscopy. Rats with obstructive jaundice (OJ group) were studied 7 days after bile duct ligation. Drainage rats were studied at 3 days (DR3 group) and 7 days (DR7 group) after the relief of 1 week obstruction of the common bile duct. In the bile duct ligated rat, the beta-adenosine triphosphate (ATP)/Pi (inorganic phosphate) ratio was significantly lower than in sham-operated controls. This ratio recovered rapidly in the DR3 and DR7 groups. The maximum increase in the phosphomonoester peak (PMEmax) after an intravenous bolus of fructose was significantly reduced in both the OJ and DR3 groups, and was accompanied by a decrease in hepatic fructokinase activity. The PMEmax and the fructokinase activity recovered in the DR7 group. In a clinical study, the beta-ATP/Pi ratio in six healthy volunteers was comparable to that of 15 patients with obstructive jaundice, regardless of their biliary drainage status. The PMEmax in all patients (serum bilirubin > or = 5 mg/dL), irrespective of biliary drainage, was significantly lower than in volunteers. Furthermore, the PMEmax in four of the eight patients with biliary drainage (serum bilirubin < 5 mg/dL) was lower than in volunteers. It is concluded that while energy status in jaundiced patients is well maintained, fructose phosphorylation is inhibited and recovery is delayed after the relief of obstruction compared with serum bilirubin. For the non-invasive evaluation of damaged liver function in jaundice, 31P magnetic resonance spectroscopy is a useful technique.

Evaluation of liver tumors using fluorine-18-fluorodeoxyglucose PET: characterization of tumor and assessment of effect of treatment.

To evaluate glucose metabolism in patients with tumors involving the liver, 35 patients with liver lesions had PET using 18F-2-fluoro-2-deoxy-D-glucose (FDG). FDG (148 MBq) was injected and radioactivity of the tumor was scanned dynamically by PET. The rate constants (k1, k2, k3, k4) of FDG in a metabolic model were calculated. The results were compared to hexokinase activity in the excised tumor specimens. k3 was found to reflect tumor hexokinase activity. When k3 was used as an index (cut-off value: 0.025), it was possible to distinguish benign and malignant tumors. k4 was significantly higher in hepatocellular carcinoma. By using k3 and k4 as indices, one could assess the degree of differentiation of hepatocellular carcinoma. After treatment, k3 decreased according to the effectiveness of therapy and thus may be a useful index for quantitatively assessing tumor viability.

Environmental dose assessment for low-level radioactive effluents discharged from Tokai reprocessing plant.

In the normal operation of the Tokai reprocessing plant, low-level radioactive effluents are discharged to the atmosphere and the ocean under rigid control. Radiation exposures to the population around the plant have been estimated for potential pathways with site-specific parameters such as food consumption, concentration factors of marine organisms, and meteorological conditions. External exposures to a radioactive cloud and internal exposures from inhalation and oral intake of radionuclides are evaluated for airborne effluents. External exposures to a contaminated fishing net and fishing boat are considered pathways for fishermen. External exposure to a contaminated beach and internal exposure via oral intake of marine products are evaluated for liquid effluents. Since the plant began operation in 1977, estimated effective dose equivalents for the public have been less than the annual effective dose equivalent limit of 0.1% recommended by the International Commission on Radiological Protection (1977).

Health expenditure growth in Japan and the United States.

This paper compares the effects of governmental policy changes on health care expenditures in Japan with similar effects in the United States. Our results indicate that Japanese economic expansion and inflation before 1982 generated higher health expenditure growth rates than those in the United States. But after a policy change in 1982, Japanese health expenditure growth dropped from 15 to 5.5 percent annually while expenditure growth in the United States remained high despite Medicare's Prospective Payment System (PPS).