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EN
There is growing evidence that endothelial dysfunction, which is often defined as the decreased endothelial-derived nitric oxide (NO) bioavailability, is a crucial factor leading to vascular disease states such as hypertension, diabetes, atherosclerosis, heart failure and cigarette smoking. This is due to the fact that the lack of NO in en- dothelium-dependent vascular disorders contributes to impaired vascular relax­ation, platelet aggregation, increased vascular smooth muscle proliferation, and en­hanced leukocyte adhesion to the endothelium. During the last several years, it has become clear that reduction of NO bioavailability in the endothelium-impaired func­tion disorders is associated with an increase in endothelial production of superoxide (O2 ). Because O2 - rapidly scavenges NO within the endothelium, a reduction of bioactive NO might occur despite an increased NO generation. Among many enzy­matic systems that are capable of producing O2 -, NAD(P)H oxidase and uncoupled endothelial NO synthase (eNOS) apparently are the main sources of O2- in the endothelialcells. It seems that O2– generated by NAD(P)H oxidase may trigger eNOS uncoupling and contribute to the endothelial balance between NO and O2–. That is maintained at diverse levels.
EN
Endothelium dysfunction, which is often defined as a decrease in NO bioavailability, is one of the earliest manifestations of endothelium-impaired function disorders, including atherosclerosis. Although improvement in NO bioavailability has been attributed to the lowering of serum cholesterol levels, recent studies suggest that HMG-CoA reductase inhibitors, statins, may have direct effects on NO bioavailability by little known mechanisms that are independent of serum cholesterol levels. The long-term effect of cerivastatin on NO release from endothelial cells was determined by using highly sensitive electrochemical microsensors and was correlated with endothelial NO synthase (eNOS) levels. To explore whether changes in isoprenoid synthesis affect NO bioavailability and eNOS expression, human endothelial cells were treated with cerivastatin, L-mevalonate (MVA; 1.5 mmol/L), geranylgeranylpyrophosphate (GGPP; 1 mg/mL) and farnesylpyrophosphate (FPP; 1 mg/mL). Cerivastatin increased spontaneous (by 53% ±6) and an eNOS-stimulated NO release (by 41 ±6% for calcium ionophore and by 47±5% acetylcholine) as well as eNOS expression (by 118 ±6%) in the same concentration-range. Cerivastatin- dependent increase in both NO release and eNOS expression was revealed after ~4 h of exposure reaching the maximum after ~10 h. Co-treatment with MVA or GGPP, but not FPP or LDL, reversed the effects of cerivastatin. These findings indicate that the long-term effect of cerivastatin resulting in enhanced NO bioavailabilty in endothelial cell is, at least in part, due to up-regulation of eNOS by blocking isoprenoids synthesis.
EN
Investigated were morphological and densitometric parameters of the tihiotarsal bones in White Kołuda Geese over postatal period as influenced by sex, age and bone area using dual-energy Xray absorptiometry and peripheral quantitative computed tomography. The study was performed on 100 bones of geese obtained from both sexes on 1, 14, 28, 42 and 56 day of life. Body weight,bone weight, bone mineral density (BMD), bone mineral content (BMC), volumetric bone mineral density (vBMD), total bone mineral content (tBMC), cortical bone mineral density (CTR_DEN),cortical bone mineral content (CRT_CNT), trabecular bone mineral density (TRAB_DEN) and trabecular bone mineral content (TRAB_CNT) of tihiotarsal bone were determined.vBMD in the proximal metaphyses generally increased with age in both sexes and in females was higher than in males (especially in mid-diaphysis). Similar trends were observed for tBMC in middiaphysis of bones. The tBMC in proximal metaphyses reached maximum in females as early as on day 28, whereas in males 2 weeks later (on day 42). A significant decrease in TRAB_DEN and TRAB_CNT was also observed in males in both sections of the bone on day 42 and 56, whereas TRAB_DEN in the mid-diaphysis attenuated between day 28 and 42. Most deformities of tibial bones in males were observed in week 6 (42 day). In females, tibiotarsal deformations and fractures were found in week 6 and 8 of age, which was slightly later than the critical developmental stage in males.
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