摘要:

The relation among glutathiqne-related enzyme activities, thiobarbituric acid-reactive substances of the human aorta and internal mammary artery, and serum lipids was studied in 40 male patients undergoing coronary revascularization. Glutathione peroxidase and glutathione reductase activities were significantly higher in the internal mammary artery, whereas glutathione transferase activity was elevated in the aortic wall. Moreover, non-seleniumdependent glutathione peroxidase activity was detectable only in the aorta. The levels of thiobarbituric acid-reactive substances were significantly higher in the aorta. A positive correlation was found among the activity of glutathione peroxidase, glutathione reductase, and thiobarbituric acid-reactive substances in the internal mammary artery and total cholesterol, low density lipoprotein cholesterol, and triglycerides. In the aortic wall, a positive correlation among the activity of glutathione peroxidase, glutathione transferase, thiobarbituric acidreactive substances, and the previously mentioned serum lipids was evident In contrast, high density lipoprotein cholesterol was inversely related to enzymatic activities and thiobarbituric acid-reactive substances in both the internal mammary artery and aorta. In conclusion, significant differences in the levels of glutathione-related enzyme activities and thiobarbituric acid-reactive substances in the internal mammary artery and aorta were found, suggesting a different ability of the two tissues to counteract oxidative stress: the glutathione-related antioxidant properties and the level of lipid peroxidation in the arterial tissue seem to be specifically influenced by serum lipids.

ISSN:1049-8834    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

This study was undertaken to examine the alterations in vascular relaxation responsiveness to endothelium-dependent or -independent vasodilators, including atrial natriuretic peptide (ANP) and acetylcholine, in aortas of Watanabe heritable hyperlipidemic (WHHL) rabbits during the progression of the atherosclerotic plaque. WHHL rabbits were divided into two groups according to age: group 1, 6-11 months, and group 2, 12-18 months. The isolated thoracic aortas obtained from both normal (control) and WHHL rabbits were suspended in a bath containing oxygenated Krebs' buffer for recording of isometric force. The endotheliumdependent relaxation evoked by acetylcholine was reduced in group 1 WHHL rabbits and decreased progressively in proportion to the degree of atherosclerosis progression when compared with age-matched control rabbits. ANP-induced relaxation was not significantly decreased in group 1 WHHL rabbits. However, ANP-induced relaxation was markedly impaired in group 2 WHHL rabbits. Thoracic aortas with severe atherosclerosis were less sensitive to ANP, with a significant increase in the median effective dose, although maximum relaxation induced by ANP was not reduced. Accumulation of cyclic GMP induced by ANP and acetylcholine was markedly reduced in atherosclerotic arteries obtained from group 2 WHHL rabbits compared with control rabbits. Vascular relaxation elicited by nitroglycerin or isoproterenol was not significantly impaired in atherosclerotic arteries from either group 1 or group 2 WHHL rabbits. From these results, we suggest that ANP-induced cyclic GMP formation and vascular relaxation via paniculate guanylate cyclase in vascular smooth muscle cells are impaired in severely atherosclerotic arteries.

ISSN:1049-8834    

出版商:OVID    

年代:1992

数据来源: OVID

摘要:

To investigate whether increased endogenous lipogenesis contributes to elevated plasma Iipid levels in individuals with apolipoprotein (apo) E2-associated hyperlipidemia (E2-HL), plasma pool cholesterol and triglyceride fatty acid syntheses were measured in subjects with E2-HL and in those with normal Iipid levels. Subjects were given a priming dose of deuterium oxide (D2O) followed by maintenance doses over 48 hours. During the first 24 hours, subjects consumed prepared meals, whereas during the 24-48-hour interval, they consumed water only. Blood samples were drawn every 12 hours, and cholesterol and triglyceride fatty acid formation rates were determined from the change in deuterium enrichment The free cholesterol fractional synthesis rate over 0-24 hours of E2-HL subjects (0.057±0.010 day"1, mean±SEM) was not significantly different from that of normolipidemics (0.075±0.005 day'1). Calculated cholesterol net synthesis was not different between the two groups (0.56±0.07 and 0.75±0.05 g/day, respectively). Mean free cholesterol synthesis for all subjects was higher in the fed (0–24-hour) compared with the fasted (24–48-hour) condition. Initial 12-hour triglyceride fatty acid fractional synthesis was significantly (p<0.01) increased in E2-HL subjects (0.143±0.012 day1) compared with controls (0.082±0.013 day1). These findings suggest that in E2-HL, elevated plasma cholesterol levels are due to factors other than increased sterol synthesis, while higher de novo fatty acid synthesis contributes to the observed hypertriglyceridemia.

ISSN:1049-8834    

出版商:OVID    

年代:1992

数据来源: OVID

ISSN:1049-8834    

出版商:OVID    

年代:1992

数据来源: OVID

ISSN:1049-8834    

出版商:OVID    

年代:1992

数据来源: OVID

ISSN:1049-8834    

出版商:OVID    

年代:1992

数据来源: OVID

ISSN:1049-8834    

出版商:OVID    

年代:1992

数据来源: OVID

ISSN:1049-8834    

出版商:OVID    

年代:1992

数据来源: OVID