Proteins hyaluronate

One very long molecule of hyaluronate is associated noncovalently with about 100 molecules of the core protein aggrecan. Each aggre-can molecule contains many covalently bound chondroitin sulfate and keratan sulfate chains. Link proteins situated at the junction between each core protein and the hyaluronate backbone mediate the core protein-hyaluronate interaction. 

Other high molecular toxins were recorded from the Apicomplexa (Sporozoa). A protein—hyaluronic acid complex (toxotoxin) was described from peritoneal exudates of mice, which is probably produced by hosts in... 

The interaction of the components of ground substance, the amorphous matrix especially found between the cells of connective tissue, has received the most study (65). Collagen particularly has been studied. Collagen, reticulin, and elastin fibers (proteins) are embedded in a viscid ground substance, which appears to contain dissolved proteins, hyaluronic acid, and sulfate esters of other zoopolysaccharides, especially of chondroitin sulfate. The soluble proteins present in connective tissue qualitatively are electro-phoretically similar to those of blood serum (66). The metachromasia shown by the ground substance (Chapter XI) results from the presence of acidic substances. Synovial (joint) fluid appears to be closely related to ground substance, but is virtually devoid of sulfate esters (67). 

Hyaluronic acid y binding domain (link-protein like)... 

FIGURE 8.46 Hyaluronic acid has the consistency of a soft gel. It absorbs water easily and bonds with the proteins in the skin, making it useful in the repair of wounds and joint injuries. 

Fingerprinting the Hyaluronic Acid-Protein Complex of Human Vitreous Humour, S. A. Barker, S. J. Crews, J. B. Marsters, and M. Stacey, Clin. Chim. Acta, 11 (1965) 139-145. 

As shown in Figure 48-8, the keratan sulfates consist of repeating Gal-GlcNAc disaccharide units containing sulfate attached to the 6 position of GlcNAc or occasionally of Gal. Type 1 is abundant in cornea, and type II is found along with chondroitin sulfate attached to hyaluronic acid in loose connective tissue. Types I and II have different attachments to protein (Figure 48—8). 

Swann, D.A. and Constable, I.J. (1972). Vitreous stmeture I. Distribution of hyaluronate and protein. Invest. Ophthalmol. 11, 159-163. 

The action of spreading factors, e. g., hyaluronidases on hyaluronic acid both in vivo and in vitro is often quite dramatic, and the effect in vitro appears to go in three stages (a) a separation of the protein residue ... 

The viability and function tests described above are used to evaluate the hepatocytes within the slice. Up to now, tests to measure the viability of the non-parenchymal cells have not been reported. The presence of the latter cell types is one of the conceptual advantages of slices as compared to isolated hepatocytes. As some drug targeting devices are designed to target non-parenchymal cells in the liver, the development of tests for the sinusoidal cell types deserves more attention. For example, the uptake of substrates such as succinylated human serum albumin (Suc-HSA,which is specifically endocytosed by endothelial cells [79]), or hyaluronic acid [80], can be used to assess the functionality of endocytotic pathways in the endothelial cells in the liver [81]. Other modified proteins that are specifically taken up by Kupffer cells such as mannosylated HSA, may be used to assess the functionality of the endocytotic pathway in Kupffer cells [79]. Another parameter which can be used to assess the functionality of these non-parenchymal liver cells, is the excretion of cytokines in response to pro-inflammatory stimuli. Non-parench5mal cell function in liver slices will be described in more detail in the Section 12.7. 

The dermis contains several types of cells, including fibroblasts, fat cells, macrophages, histiocytes, mast cells, and cells associated with the blood vessels and nerves of the skin. The predominant cell is the fibroblast, which is associated with biosynthesis of the fibrous proteins and ground substances such as hyaluronic acid, chondroitin sulfates, and mucopolysaccharides. 

---