Capillaries sprouting

Neovascularization, the formation of new blood vessels, is an essential life process. TCDD interferes with neovascularization by inhibiting the formation of new capillary sprouts from preexisting vessels (angiogenesis). ... 

Vascular invasion and capillary sprouting within the invading tissue with capillary elongation in close contact with the implanted hydroxyapatite biomatrix. 

A similar approach to tumor uptake mechanism has been presented (5iL) In this case, the gallium-67 is assumed to accumulate in tumor cells in an unknown manner because of Increased deposition of the radionuclide at the tumor site in an inflammatory response. Because acute inflammation is associated with increased capillary blood flow and permeability ( ) as well as capillary sprouting (86), these changes allow more Ga to be delivered to the tumor site. This simple mechanism offers the advantage of explaining why gallium accumulates only in viable (not necrotic) neoplasms (53.) and that it may operate... 

FIGURE 83.2 Extravasation of liposomes in normal and tumor tissues. The fluorescently labeled liposomes are shown as bright pixels and some of them are indicated by the arrows. Panel (a) shows that liposomes accumulate only in perivascular regions in solid tumors. Bar, 100 pm. Panel (b) shows that two vascular networks on the surface of a tumor have different patterns of liposome accumulation, indicating that microvascular permeability is heterogeneous in solid tumors. Bar, 400 pm. Panel (c) shows that extravasated liposomes are mostly located near the roots of capillary sprouts (bottom), while the capillary sprouts per se (top) are nearly impermeable to liposomes. Bar, 200 pm. Panel (d) shows that liposome accumulation in normal subcutaneous tissues occurs only in endothelial cells in postcapillary and collecting venules (6-25 pm in diameter). The letters a, c, and v represent arteriole, capillary, and venule, respectively. Bar, 100 pm. (Reprinted from Yuan F et al. Cancer Res 1994 54 3352-3356. With permission.)... 

Figure 1. Angiogenesis and its Inhibition. Growth factors induce blood capillaries (left) to sprout endothelial cells proliferate. Inhibition (anti-angiogenesis) is effected by the pair H-cortisone + heparin.

For example, the suitability of the gels to support the growth of endothelial cells was evaluated since endothelial cells play a crucial role in the sprouting of capillary blood microvascular vessels. A lack of vascularisation is a major obstacle for successful tissue engineering therapies, as it results in insufficient nutrient supply... 

Osteoconductive Capable of supporting in-growth of sprouting capillaries, perivascular mesenchymal tissues, and osteoprogenitor cells from the recipient host into the three dimensional structure of a graft that act as a scaffold. 

Sprouting capillaries (Wakui 1988) are characterised by small, slitlike lumina and thick-walled endothehal cells that contain numerous cytoplasmic organelles. In densely fibrotic lesions, regenerating endothelial cells contained numerous free ribosomes, cistern of the rough endoplasmic reticulum, numerous microfilaments, and Weibel-Palade bodies (Kawanami et al. 1995). The microfilaments often showed dense insertion sites along the abluminal plasmalemma. 

Angiogenesis, the sprouting of new capillaries fi om preexisting vessels, is a complex multistep process. It requires extensive interactions between a variety of cells and molecules and is controlled by various peptides and other modulating... 

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