Esterified Hyaluronan HYAFF

The HYAFF esterfied hyaluronans are versatile and well-studied biomaterials. Esterfication results in the loss of hydrophilicity and hydrogen bonding by masking the free carboxylic group, and the simultaneous increase of hydrophobilicity by the introduction of alkyl or benzyl groups. As a result, most HYAFF materials are insoluble in water. Instead, HYAFF materials can be dissolved in organic solvents and extruded to produce membranes and fibers, lyophilized to obtain sponges, or spray-dried to...

References

Mammalian hyaluronan synthases. IUBMB Life 2002 54 195-199. 2. Day AJ, Prestwich GD. Hyaluronan-binding proteins tying up the giant. J Biol Chem 2002 277 4585-4588. 3. Turley EA, Noble PW, Bourguignon LY. Signaling properties of hyaluronan receptors. J Biol Chem 2002 277 4589-4592. Ponta H, Sherman L, Herrlich PA. CD44 from adhesion molecules to signalling regulators. Nat Rev Mol Cell Biol 2003 4 33-45. Rittig M, Lutjen-Drecoll E, Prehm P. Immunohistochemical localization of...

Hyaluronan in Atherosclerosis

Atherosclerosis is a disease of medium and large-sized arteries that claims more lives in the western world than any other disease (12). The disease involves the progressive thickening of blood vessels over several decades of life due to accumulations of cells, components of the extracellular matrix (ECM) and deposits of lipids in the form of lipoproteins with the eventual formation of the atherosclerotic plaque. With time, the plaques weaken and rupture leading to thrombosis and occlusion...

Hyaluronan in Restenosis

Vessels that become blocked can be treated by removing the plaque by percutaneous transluminal angioplasty, which surgically splits or dissects the plaque to reopen the blood vessel (61). However, in a large percentage of these patients, the treated vessels reocclude in a remarkably short period of time (3 -6 months), necessitating further surgery. This process of reocclusion is called restenosis and is thought to involve a combination of blood vessel thickening and tissue shrinkage (62). Data...

Viscometry A Theory

Measurement of the viscosity of a solution containing hyaluronan allows the determination of the polymer viscosity-average (close to the weight-average) molecular weight. The theoretical basis for this effect is conceptually simple (1). The Stokes-Einstein relation for the specific viscosity, -sp, of a dilute suspension of n spherical particles per unit volume of suspension, each with volume V, is where - and -0 are the respective viscosities of the suspension and pure fluid. The product, nV,...

Covalent Crosslinked Hyaluronan Based Biomaterials

Originally developed in the early 1980s by Balazs and commercialized by Biomatrix, Inc., Hylan is produced by chemically crosslinking the hyaluronan containing residual proteins with formaldehyde (soluble gel) or divinyl sulfone (119). These materials are now marketed by Genzyme Corporation. Soluble Hylan A is a very high molecular weight form (8-23 MDa) of hyaluronan (5 -6 MDa) that exhibits enhanced rheological properties compared to native hyaluronan, and is used in ophthalmic viscosurgery...

Summary and Conclusion

In recent years, a growing number of physiological and biological roles have been ascribed to hyaluronan in addition to is role as an essential structural component of the ECM. Its rheological properties have led to an increasing number of applications for hyaluronan in the pharmaceutical industry. Hyaluronan preparations from different biological sources are finding applications in ophthalmology, cosmetics and drug delivery. The chemical modification of hyaluronan to alter its physical...

Hyaluronidase Mediated Degradation

Hyaluronidases are considered responsible for much of the HA catabolism taking place in the organisms (see Chapter 17 for details). Successful fertilization in mammals is dependent on the action of hyaluronidase, when the sperm traverses the outermost HA-rich cumulus layer surrounding the egg (32). Therefore, all mammalian spermatozoa bear hyaluronidase activity. A protein, first of all characterized with the aid of a monoclonal antibody against posterior head determinants and thus named PH-20...

Elastic Offline Light Scattering Batch Mode

Average values of the molecular weight and of the size could be obtained by elastic offline LS, that is in batch mode. In batch LS mode a number of concentrations, usually from 3 to 5, is prepared and the intensity of the scattering is measured. Obviously in a MALS instrument the intensity of the scattering at different angles is also simultaneously measured by an array of photodiodes in each single scan. The concentration of the sample solutions has to be chosen on the basis of the...

C Rhamm and Tumor Progression

As we have noted earlier, the tissue remodeling that occurs with wound repair resembles that occurring during neoplastic progression 56-59 . In particular, the presence of chronic tissue fibrosis, associated with hyper-expression of both CD44 and RHAMM appears to provide favorable conditions for sustaining neoplastic conversion and progression. The similarity between the two processes is reflected by the fact that RHAMM mRNA expression is specifically upregulated in tumors and the appearance of...

B Rhamm as a TACC

The TACC family of proteins include human TACC3, murine TACC3, human TACC2 AZU-1 ECTACC, human TACC1, D-TACC and murine AINT 102 . Members of this family of proteins are defined by the presence of the so-called TACC domain, a predicted coiled-coil region in their carboxyl terminus 102 . In fact, the TACC proteins show the most similarity in this region as they share very little sequence identity throughout the rest of their protein sequence Fig. 3A 102 . In addition to the TACC domain, all...

Acknowledgements

This work was supported in part by a preparatory grant for research at the Matrix Glycoconjugate group, Research Center for Infectious Disease, Aichi Medical University Grant-in-Aid for Scientific Research on Priority Areas 14082206 from the Ministry of Education, Culture, Sports, Science, and Technology of Japan a grant-in-Aid for Scientific Research B from Japan Society for the Promotion of Science JSPS grants from the CREST of JST Japan Science and Technology Agency Health Science Research...