Effect of lipopolysaccharide on the adherence of human umbilical vein endothelial cells (HUVEC) on a natural substrate.

 Polymers are often contaminated with lipopolysaccharides also known as endotoxins. Even small amounts of endotoxins can have strong effects on endothelial cell function so that the endothelialisation of cardiovascular implants might be hampered. An open question is how endothelial cells seeded on a body foreign substrate respond to shear load after adding Lipid A (LPA), the domain, which is responsible for much of the toxicity of gram-negative bacteria, and whether morphological changes of endothelial cells occur.

Shear resistance of endothelial cells in a pathological environment.

Background: Endothelial cells (EC) in vivo are strongly influenced by changes of the milieu exterieur. Under pathological conditions EC can become activated e.g.

Effect of radiographic contrast media on the spectrin/band3-network of the membrane skeleton of erythrocytes.

The membrane of red blood cells consists of a phospholipid bilayer with embedded membrane proteins and is associated on the cytoplasmatic side with a network of proteins, the membrane skeleton. Band3 has an important role as centre of the functional complexes e.g.

Influence of various radiographic contrast media on the buckling of endothelial cells.

The intra-arterial application of radiographic contrast media (RCM) can induce decreases of blood flow velocity in downstream capillaries as well as a decrease in the tissue oxygen tension. It is unclear whether changes in endothelial cell morphology contribute to the observed microcirculatory disorders. Four RCMs (Iodixanol320, Iohexol350, Iopromide370, and Imeron350) were added to the culture medium of human umbilical venous endothelial cells (HUVEC) and used for short-term incubation studies of these cells.

Observations on the microvasculature of bone defects filled with biodegradable nanoparticulate hydroxyapatite.

The microvascularization of metaphyseal bone defects filled with nanoparticulate, biodegradable hydroxyapatite biomaterial with and without platelet factors enrichment was investigated in a minipig model. Results from morphological analysis and PECAM-1 immunohistochemistry showed the formation of new blood vessels into the bone defects by sprouting and intussusception of pre-existing ones. However, no significant differences were observed in the microvascularization of the different biomaterials applied (pure versus platelet factors-enriched hydroxyapatite), concerning the number of vessels and their morphological structure at day 20 after operation.

Effects of platelet factors on biodegradation and osteogenesis in metaphyseal defects filled with nanoparticular hydroxyapatite--an experimental study in minipigs.

There are no studies on the cellular activity in the early phase of biodegradation and bone healing of bone substitutes loaded with platelet factors (PLF). The purpose of this study was to evaluate the cellular effects of PLF in combination with nanoparticulate hydroxyapatite (HA) on the biodegradation and bone formation after 20 days. Autogenous PLFs were obtained by centrifugation of miniature pig blood samples and subsequent degranulation of platelets by calcium and thrombin.