No description available.

No description available.

Interactions between serum lipoproteins and human cells in the secretion of glycosaminoglycans (GAG) were investigated in cultures of arterial smooth muscle cells (SMC) and fibroblasts. Lipoprotein free serum (LFS) supported cell proliferation but caused a dose-dependent decrease in GAG secretion and cell cholesterol. Addition of low density lipoproteins (LDL) to 10% LFS in the medium caused increases in GAG secretion and cell cholesterol but a net decrease in cell population. LDL effects were positively correlated with the rate of cell proliferation independent of serum concentration. High density lipoproteins (HDL) decreased GAG secretion in slowly but not in actively proliferating cultures; however in the latter, it reduced all LDL-induced changes. Cells from non insulin-dependent diabetics had an increased GAG response to LDL. Low concentrations of platelet factors enhanced GAG secretion. The addition of a GAG mixture inhibited all LDL effects. On the basis of these observations, a hypothetical model is presented indicating that GAGs play a significant role in the development of atherosclerosis.

Collagen production by skin fibroblast cell strains from normal subjects and age-matched patients with the mendelian disorder--Osteogenesis Imperfecta (OI)--was studied in culture. / Number of generations in culture, phase of growth, labelling times, and site of biopsy did not influence collagen production by normal skin fibroblasts. / OI cell strains from patients with dominantly inherited OI have abnormal morphology and growth in culture. The ratio of Type I to protype III collagen is reduced in OI Types I, II and IV (Sillence classification). Type III OI could not be distinguished from normal strains by the analysis used. From the collagen phenotype (biochemical parameters) we were able to distinguish different OI phenotypes and to correlate these with clinical phenotypes. One form of OI Type I produces an unstable collagen that is degraded to small peptides in culture.

No description available.

Mechanical stress has been shown to play a role in bone remodelling during orthodontic tooth movement. Receptor activator of nuclear factor kβ - ligand (RANKL), osteoprotegerin (OPG), monocyte colony stimulating factor (M-CSF) and interleukin 1-β (IL-1β) play key roles in the regulation of bone remodelling, but the role of these cytokines in orthodontic tooth movement is poorly understood. Aim: The aim of this experiment was to examine the response of periodontal ligament (PDL) fibroblasts in monolayer culture to intermittent tensile stress as regards RANKL, OPG, M-CSF and IL-1β production. Methods: Human PDL fibroblasts were dissected from premolars extracted for orthodontic purposes. Explants were seeded out in 1cm wells and grown to confluence in Dulbecco�s modification of Eagle�s medium, containing 10% foetal calf serum and antibiotics, at 37�C in a humidified atmosphere of 5% CO₂/95% air. Upon reaching confluence, the cells were passaged into sequentially larger flasks. Fibroblasts were passaged 6 times. After reaching confluence in T175 flasks, the cells were detached and plated at a cell density of 10⁵/dish in 35mm Bioflex� Plates coated with type 1 collagen. The cells were placed under a continuous uni-axial strain of 12% for 6s of every 90s by a Flexercell FX 4000C[TM] for 0, 12, 24 and 48 hours. Cells were then detached and stored in RNAlater. Quantitative RT-PCR was used to determine the mRNA of the cytokines of interest. Results: Tensile force led to the down regulation of mRNA expression for OPG and IL-1β at 12 and 24 hours respectively, while M-CSF was up-regulated at 6 hours. RANKL was not detected at a significant level for quantification. Conclusion: This osteoclastic-type response indicates the complexity of mechanotransduction in an in vitro setting. Acknowledgments: This research was supported by the New Zealand Dental Research Foundation, the New Zealand Lottery Grants Board and the New Zealand Association of Orthodontists.

The aim of this project is to characterise the levels of cholesterol and phospholipid in cell homogenates, plasma membranes and isolated membrane domains from wildtype (WT) and caveolin-l knock-out (Cav-1-/ -) mouse embryonic fibroblasts (MEFs). Quantitative lipid analysis was developed for cholesterol by high-performance liquid chromatography (HPLC) and for glycerophospholipids (GPL) and sphingomyelin (SM) by electrospray ionisation mass spectrometry (ESI-MS). In the cell homogenates, by comparing WT to Cav-l-/- MEFs, it was found that the total cholesterol as well as the proportions of the main GPLs such as Phosphatidylcholines (PC), phosphatidylethanolamine (PE), phosphatidylserine (PS) was similar in both cell types. However, Cav-l-/- MEFs have higher levels of cholesterol esters than WT MEFs in whole cell homogenate. Furthermore, the proportion of SM is higher in Cav-l-/- than WT MEFs. These data suggest that Cav-l may control the balance between free and esterified cholesterol and is involved in SM metabolism. A small increase in SM level in Cav-l-/- compared to WT plasma membrane was observed but this increase was not significant. Similarly, cholesterol levels in the plasma membrane are comparable between the two cell types. In both cell types, the levels of SM and phosphatidylglycerol (PG) are higher in the plasma membranes than in cell homogenates. In the WT cells, PE levels are higher in the plasma membrane than in the cell homogenates. While in the Cav-1-/- cells, the level of free cholesterol and PC are higher in the plasma membrane compared to the cell homogenate. PCs are the predominant lipids in both cell types. Cav-1-l - cells have more saturated fatty acyl chains in their PC species and shorter carbon chains compared to WT MEFs and this trend was found in both cell homogenate and plasma membranes. In PEs and SMs, Cav-1-/ - cells also have higher levels of saturated PEs and saturated amide-linkage SM than in WT cells, respectively. The results indicate that Cav-1 may also play a role in fatty acids metabolism. In summary, the data from this work indicate that Cav-l expression affects lipid composition in MEFs including the relative distribution of free and esterified cholesterol, the levels of SM relative to other phospholipid subclasses and the incorporation of fatty acids into phospholipids.

Thesis (Ph.D.)--Tufts University, 2005. / Adviser: David L. Kaplan. Submitted to the Dept. of Chemical Engineering. Includes bibliographical references (leaves 206-217). Access restricted to members of the Tufts University community. Also available via the World Wide Web;

Dissertation (Ph.D.).--University of Texas Graduate School of Biomedical Sciences at San Antonio, 2006. / Vita. Includes bibliographical references.

Thesis (M.S.)--Ohio University, August, 1995. / Title from PDF t.p.