Motohiro Fujino

The effect of oxygen on the development of atherosclerosis in WHHL rabbits

The effect of hyperoxic or hypoxic inhalation on blood lipid levels and on the development of atherosclerosis was studied in young male WHHL rabbits. They were exposed to ordinary room air containing different concentrations of oxygen: 6 animals were exposed to 40% oxygen (hyperoxia group) or 5-10% oxygen (hypoxia group) for 5 h a day, 5 days a week for 8 weeks. Four control rabbits inhaled ordinary room air. The following results were obtained. (1) The severity of aortic lesions significantly decreased in the hyperoxia group and increased in the hypoxia group, when these two groups were compared. However, both hypoxic and hyperoxic groups did not statistically differ from the control. (2) Plasma cholesterol levels were not changed either by hyperoxic or hypoxic inhalation. (3) Plasma triglyceride levels were elevated only in the hypoxia group, with significant differences from the values in both control and hyperoxia groups. (4) There was no significant correlation between mean plasma lipid level and severity of aortic lesions. From these results, we conclude that hyperoxic or hypoxic inhalation respectively regresses or aggravates the development of atherosclerotic lesions, not by an indirect action on blood lipid concentrations but by a direct action on the vascular wall.

CHROMIUM-INDUCED PULMONARY CANCER: Report of a Case and a Review of the Literature

A 57‐year‐old man, whose occupational history was that of a chromate worker for about 35 years, suffered nasal perforation during and died due to pulmonary cancer. In the autopsy materials, the concentration of chromium in the lung tissues was very high, being about 90 times the amount found in normal lungs. The chromium particles in the lung tissues could not be detected by analytical electron microscope, but they could be found in the anthoracotic lesions of the lungs by means of an X‐ray microanalyser. The present case was judged to be a case of chromium‐induced pulmonary cancer since all the pathologic data obtained were similar to those found in similar cases reported in the literature, ACTA PATHOL. JPN. 35: 643–654, 1985.

ULTRASTRUCTURAL STUDIES OF THE MOUSE AORTA AND ITS ENDOTHELIAL PINOCYTOSIS IN DIETINDUCED ARTERIOSCLEROSIS

In mice fed on an atherogenic diet for 4 to 8 months, the aortas were examined by transmission and scanning electron microscopy. After 8 months of being fed a high cholesterol diet, the animals developed aortic intimal lesions composed mainly of proliferated modified smooth muscle cells with an increase of connective tissues. Scanning electron microscopy showed changes in aortic luminal surface consisting primarily of altered distribition of microvilli. Quantitative analysis of these changes showed a statistically significant (P<0.001) increase in cholesterol‐fed animals compared with controls and a significant (P<0.001) difference between at 4 months and at 8 months in cholesterol‐fed mice. Ultrastructural study on the uptake of protein tracer, horseradish peroxidase (HRP), by aortic endothelial cells in vitro was performed. The uptake of HRP was essentially the same for controls and cholesterol‐fed mice at 4 months, but a statistically significant (P<0.005) increased uptake of HRP was observed at 8 months. Additional mice were subjected to nephrectomy with DOCA administration for 4 months along with a cholesterol‐feeding. These animals showed a 2‐fold increase in HRP‐uptake compared with nephrectomized mice without a cholesterol‐feeding. These results suggest that the enhanced pinocytotic activity of aortic endothelial cells in vitro, especially in hypertensive condition, and altered distribution of microvilli might be correlated to the arteriosclerotic process.

Increased 201Tl uptake by the chest wall following cardioversion.

A patient with acute inferior infarct is described who showed increased 201Tl uptake in the anterior chest wall following cardioversion which mimicked increased lung uptake of the tracer. The site of accumulation of 201Tl corresponded to that of 99mTc-pyrophosphate (PYP) and the right sided catheterization revealed almost normal hemodynamic data.