Sei Emura

Risk factors of atherosclerosis and aortic pulse wave velocity.

Aortic pulse wave velocity (PWV) is a noninvasive technique that can estimate aortic stiffness or organic change quantitatively. The authors examined the correlation between age and the PWV value in 113 subjects and also examined the relationship between ather osclerotic associated diseases and PWV. A positive correlation was observed between age and the PWV value. No significant difference was found in the PWV value between groups with and without risk factors of atherosclerosis. No significant difference was observed in the PWV value between groups with and without a history of atherosclerotic disease.

Successful Treatment of Intermittent Claudication Due to Spinal Canal Stenosis Using Beraprost Sodium, a Stable Prostaglandin I2 Analogue: A Case Report

The syndrome of intermittent claudication can be induced not only by vascular insuffi ciency of the lower limbs but also by diseases of the spinal cord and cauda equina. The authors describe a sixty-year-old man with intermittent claudication due to spinal canal stenosis who was successfully treated with beraprost sodium, a stable prostaglandin I2 analogue. This drug has a long biological half-life and is orally effective in vasodilation, which is suggested to be beneficial in treating this syndrome. Beraprost sodium may become one of the major drugs for conservative therapy of intermittent claudication induced by spinal canal stenosis.

Quantitative analysis of antiatherosclerotic effect of nifedipine in cholesterol-fed rabbits

SummaryReports concerning the effect of slow calciumchannel blockers on experimental atherosclerosis are controversial. We examined the antiatherosclerotic effect of nifedipine (40 mg/day for 16 weeks) on aorta of rabbits on diets containing 0.3%, 0.5%, and 1.0% cholesterol. There were no significant differences in levels of serum lipids with or without nifedipine in the same cholesterol-fed rabbits. The results obtained show that nifedipine suppressed the extent of lipid deposition and surface involvement (S.I) in aorta in 0.3% cholesterol-fed rabbits, whereas nifedipine only tended to suppress S.I. in 0.5% cholesterol-fed rabbits and had no effect in 1.0% cholesterol-fed rabbits. The log dose-response relationship of S.I. was obtained by plotting the concentration of cholesterol in the feed or the “integrated value” of the total serum cholesterol (TC), i.e., the cumulative sum of the serum TC values obtained at each week. The log, doseresponse curve was shifted in parallel with the right in nifedipine groups. The Lineweaver-Burk plot constructed from the dose-response curve had the same points crossing the ordinate with or without nifedipine. These results suggested that nifedipine suppressed S.I. in a competitive manner with cholesterol on the specific binding site of lipid deposition. Electron-microscopic findings also demonstrated that fat droplets in smooth muscle cells, extracellular matrix containing collagen, and elastic fibers decreased in nifedipinetreated rabbits.

Fine Structures Around the Orifice of the Intercostal Artery of the Rabbit Thoracic Aorta

In hypercholesterolemic rabbits, atherosclerotic lesions easily occur in the thoracic aorta, especially at the distal and lateral sides of the walls around the orifices of the dorsal intercostal arteries. In order to examine whether some spe cial structures that lead to atherosclerotic lesions are present even in normal con ditions, the authors investigated the morphologic features around the orifice of the intercostal artery of 20 normal rabbit aortae under electron microscopy. The endothelial cells were generally fusiform but tended to be round and have a cobblestone-like appearance at the lateral side. There was intimal protrusion at the distal and lateral sides of the orifice, where the distribution and arrange ment of elastic fibers and smooth muscle cells were different from those at the proximal side. At the proximal edge of the orifice, elastic fibers formed a thick plate-like internal elastic lamina beneath the endothelial cells. On the other hand, at the distal and lateral sides, elastic fibers formed close-meshed structures over the proper plate-like internal elastic lamina. These results indicate that the aortic walls at the distal and lateral sides of the orifice are structurally different from those at other regions even in normal conditions and suggest the involvement of special structures at the distal and lateral sides of the orifice in atherogenesis.

Heterogeneity of Rabbit Aortic Endothelial Cells, with Special Reference to Phagocytosis

Heterogeneity of aortic endothelial cells with regard to phagocytotic ability was examined by injecting India ink into normal rabbits. Light and electron microscopic analyses revealed that particles of India ink were phagocytosed in the endothelial cells, which in turn were localized at the distal side of the orifice of aortic branches, especially those of brachiocephalic, left calvicular, and dor sal intercostal arteries. No remarkable differences were found ultrastructurally between phagocytosing and nonphagocytosing endothelial cells. Ingested India ink particles were present within phagosomes of the endothelial cells for several hours after injection; the particles eventually accumulated in the subendothelial space twenty-four hours after injection. These results indicate that an active transport system of large molecules via the phagocytotic processes is present in endothelial cells located at the distal sides of the orifice of aortic branches. These regions are known to develop initial atherosclerotic lesions in hypercholesterolemic animals. Thus, a possible corre lation between phagocytotic ability of endothelial cells and development of atherosclerosis is suggested.

The Antiatherogenic Effect of Nifedipine on Intramural Small Coronary Arterial Lesions in Cholesterol-Fed Rabbits

The objective of this study was to examine the suppressive effect of nifedipine on intra mural coronary arterial lesions in cholesterol-fed rabbits. Each rabbit in Groups A (n=6) and B (n=5) was fed a 0.3% cholesterol diet and was orally administered nifedipine (40 mg/day) or placebo. Each rabbit in Groups C (n=5) and D (n=6) was fed a 0.5% choles terol diet and was orally administered nifedipine (40 mg/day) or placebo. The serum concentrations of total cholesterol (TC) were determined at 1-week intervals to calculate the integrated values. The lesion induction ratio was defined as the ratio of intramural coronary arteries 50-150 μm in diameter with arterial lipoidosis to the total number of arteries of the same diameter. There were no significant differences between the nifedipine-treated and placebo groups in either the integrated TC or lesion induction ratio in either the 0.3% and 0.5% cholesterol-fed rabbits. This study demonstrates that nifedipine does not suppress atherogenesis in the intramural small coronary arteries of cholesterol-fed rabbits.

Arm span–height difference is correlated with gastroesophageal reflux symptoms in aged Japanese subjects

Previous studies have indicated an association between the symptoms of gastroesophageal reflux disease (GERD) and aging plus height. In this study we investigated whether the arm span–height difference was related to GERD symptoms with a focus on aged subjects in the general population, since the arm span reflects the height in young adulthood before decreasing due to vertebral deformities from aging. A total of 285 elderly individuals (105 females) who visited nursing homes for the elderly in Japan were enrolled in this study. The GERD symptoms were evaluated by the Frequency Scale for the Symptoms of GERD (FSSG). The body weight, height and arm span were measured, and information regarding medications and complications were reviewed in each nursing record. 50.5% of women had more than 3 cm of arm span–height difference. In contrast, only 37.3% of men had more than 3 cm of arm span–height difference. The FSSG scores indicated more than 70% of subjects complained of any GERD symptoms. There was a significant correlation between the FSSG score and the arm span–height difference in the subjects with more than 3 cm of arm span-height difference (r = 0.236; p = 0.012). The correlation between the arm span–height difference and the FSSG score was significant only in women in females in the present study. In conclusion, our findings indicate that vertebral deformity evaluated by the arm span–height difference might have some positive relationship to the pathogenesis of GERD symptoms in elderly Japanese individuals.

Suppressive Effect of Simvastatin on Intramural Small Coronary Arterial Lesions in Cholesterol-Fed Rabbits

The aim of this study was to examine the suppressive effect of simvastatin on intramural coronary arterial lesions in cholesterol-fed rabbits. In one experiment, six groups of rabbits were fed laboratory chow alone or with added 0.1%, 0.2%, 0.3%, 0.5% or 1.0% cholesterol for 16 weeks. In another experiment, four groups of rabbits were fed a 0.5% cholesterol diet and treated with simvastatin at 1, 3, or 5 mg/kg/day or placebo. In each rabbit, the levels of serum total cholesterol (TC) were determined at 1-week intervals to calculate the integrated values. The lesion induction ratio was defined as the ratio of intramural coronary arteries 50-150 μm in diameter with arterial lipoidosis to the total number of arteries of the same diameter. In the two experiments, there were positive correlations between the lesion induction ratio and integrated TC (r=0.785, P < 0.0001 and r=0.763, P<0.0001, respectively). The slopes of the regression lines for integrated TC obtained in the two experiments were similar, but the lesion induction ratio in the simvastatin-treated group was always lower, by about 14%, in comparison with that in the nonsimvastatin-treated group. These findings suggest that simvastatin induces lesion reduction not only by reducing the levels of circulating cholesterol but also by directly suppressing the development of lipoidosis.

Initiation of Atherosclerosis: Giant Endothelial Cells, Intimal Constriction, and Late Replacement of Damaged Endothelial Cells

Forty male rabbits were used for the experiment: the first group of 10 were infused with adrenaline solution (0.1-10 pg/Kg/min for 15 min); the second group of 10 with noradrenaline (0.1-10 pg/Kg/min for 15 min); and a third group of 20 were fed 1% cholesterol feed for 12-18 weeks. All anesthetized animals were sacrificed by intracardiac perfusion with 110 mmHg of glutaraldehyde for 15-60 rnin. Sample tissues were taken from the thoracic aorta; upon removal, the tissue was cut into small pieces and promptly immersed in fixative. Electronmicroscopic observation was performed by the ordinary method.