Viscosurgery

As has been described above, HA is an essential functional component of almost all tissues in the vertebrate organism. Thus, various animal tissues - e.g. rooster combs, shark skin, bovine eyeballs - have been used as sources of isolation and production of high molar mass HAs. Since in the biological materials HA is usually present in a complex linked to other biopolymers, several separation procedures have to be applied in order to obtain a pure compound, such as protease digestion, HA ion-pair precipitation (with e.g. cetylpyridinium chloride), membrane ultrafiltration, HA non-solvent precipitation and/or lyophilization [135,136]. The mean molar mass of the commercially available extractive HA preparations obtained from animal tissues is mostly in the range from several hundred thousands Da up to approximately 2.5 MDa. To date, the demand for HA materials approved for applications in human medicine has been satisfied by high molar mass HAs prepared from the rooster combs. For example, Healon (Pharmacia Upjohn, Inc., Peapack, NJ, USA) - used in viscosurgery at eye implant insertion - has a mean HA molar mass of about 2.5 MDa. 

Balazs EA, Miller D, Stegmann R. Viscosurgery and the use of Na-hyaluro-nate in intraocular lens implantation. In International Congress and First Film Festival on Intraocular Implantation, Cannes, France, 1979 l-6. 

Eisner G, ed. Ophthalmic Viscosurgery A Review of Standards, Techniques and Applications. Montreal, Canada Medicopea, 1986. 

One interesting use of HA is in the field of viscosurgery and viscosupplementation. In reproductive medicine, HA enhances the retention of the mobility of cryo-preserved and thawed spermatozoa. This property is used to select viable spermatozoa and Improve artificial insemination and other in vitro fertilization methods. 

Alpar JJ. Viscosurgery a review of materials, indications, techniques and precautions. Eisner G (ed) Ophthalmic Viscosurgery A Review of Standards, Techniques and Applications. Bern, Switzerland, Medicopea International, 1986, S. 39-53... 

Succinylated ateolocollagen solution for use in viscosurgery and as a vitreous substitute 4,748,152 1988 Miyata... 

Viscosurgery Elastoviscous solutions and viscoelastic gels used as surgical tools and implants to protect sensitive tissues from mechanical damage during and after surgery. [47 9]... 

Biomatrix I. Viscosurgery a historical perspective. In Kennedy JF, Phillips GO, Williams PA, Hascall VC, editors Hyaluronan. Cambridge Woodhead Publishing Ltd 2002. p. 461-5. 

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