PubMed · 4741925
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
S P Allwork, R H Bentall. 1973. Truncus solitarius pulmonalis.. https://doi.org/10.1136/hrt.35.9.977
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
The role of elastin in the aortic wall calcification and involved mechanisms were investigated. The major hypothesis of this work is that elastin is one of the major components to regulate calcification of bioprosthetic heart valve (BHV). The relationship between the elastin content and the calcification rate of the aortic wall was established using collagen-elastin matrices (CEM) made of varying ratios of collagen and elastin (90 and 10, 50 and 50, and 20 and 80). Biophysical characterization of CEM was performed by water content measurement and the tensile strength test. The conformational changes of the calcifiable matrix were evaluated as a function of elastin content using Fourier transform infrared (FTIR) spectroscopy. The calcium contents in CEM implanted in the rat subcutaneous model for 7 days were measured using atomic absorption (AA) spectroscopy. As the concentration of elastin in CEM increased from 10 to 80%, the total amount of calcium accumulated in CEM also increased. The calcium level in CEM containing the collagen and an elastin ratio of 20:80 was 20.16 +/- 0.70 microg/mg compared with 1.96 +/- 0.04 microg/mg in CEM containing the collagen and an elastin ratio of 90:10. The calcification rate of CEM pretreated with ethanol increased, as the elastin concentration in the CEM. However, the calcification rate of CEM pretreated with ethanol is significantly lower than that of the untreated control. The permeation rate of ethanol through CEM with the collagen and an elastin ratio of 20:80 (0.37 +/- 0.13 mmol/cm(2)/h) is significantly smaller than that through CEM with 90:10 (0.94 +/- 0.27 mmol/cm(2)/h). These results indicate that elastin has a significant role in tissue calcification and that elastin's resistance to ethanol penetration partially contributes less effectiveness of ethanol on aortic wall calcification.
The role of angiogenesis in the growth and metastasis of solid tumors is well established. However, the role of angiogenesis in hematologic malignancies was only recently appreciated. We show that HTLV-I-transformed T cells, but not HTLV-I-negative CD4(+) T cells, secrete biologically active forms of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) and, accordingly, induce angiogenesis in vitro. Furthermore, fresh ATL leukemic cells derived from patients with acute ATL produce VEGF and bFGF transcripts and proteins. The viral transactivator Tax activates the VEGF promoter, linking the induction of angiogenesis to viral gene expression. Angiogenesis is associated with the adhesion of HTLV-I-transformed cells to endothelial cells and gap junction-mediated heterocellular communication between the 2 cell types. Angiogenesis, cell adhesion, and communication likely contribute to the development of adult T-cell leukemia-lymphoma and represent potential therapeutic targets.
BACKGROUND: Tissue factor plays a pivotal role in thrombus formation in acute coronary syndromes. However, the regulatory mechanisms underlying tissue factor expression are poorly understood. Statins are effective in patients with acute coronary syndromes. Hence, the aim of this study was to clarify in human endothelial cells the signaling pathways of thrombin-induced tissue factor expression and potential inhibitory effects of statins. METHODS AND RESULTS: In human aortic endothelial cells, simvastatin prevented tissue factor induction by thrombin (4 U/mL) in a concentration-dependent manner. The increase in tissue factor activity on the cell surface was also blocked by simvastatin. Simvastatin also prevented the upregulation of tissue factor expression and activity in human aortic smooth muscle cells. Mevalonate (100 micromol/L) reversed the inhibitory effect of simvastatin on tissue factor expression. Thrombin induced rapid activation of Rho A and p38 MAP kinase. The Rho-kinase inhibitor Y-27632 and the p38 MAP kinase inhibitor SB203580 prevented tissue factor induction. Akt was dephosphorylated by thrombin; the phosphoinositol 3-kinase inhibitor wortmannin enhanced its dephosphorylation as well as thrombin-induced tissue factor expression. Simvastatin prevented thrombin-induced Rho A activation but not p38 MAP kinase activation. Akt dephosphorylation by thrombin was blocked by both simvastatin and Y-27632. CONCLUSIONS: Endothelial tissue factor induction by thrombin is regulated by Rho/Rho-kinase, Akt, and p38 MAP kinase. Simvastatin prevents its induction through inhibition of Rho/Rho-kinase and activation of Akt. These findings provide new insights into the action of statins in acute coronary syndromes.