Collagen hydration

Berisio, R., Vitagliano, L., Mazzarella, L., and Zagari, A. (2001). Crystal structure of a collagen-like polypeptide with repeating sequence Pro-Hyp-Gly at 1.4A resolution Implications for collagen hydration. Biopolymers 56, 8-13. 

Bella, J., Brodsky, B., Berman, H.M. Hydration structure of a collagen peptide. Structure 3 893-906, 1995. 

The effect of various chemical modifications on the mechanical properties of reconstituted collagen and the diffusion rates of the steroid medroxyprogesterone was investigated (38). Formaldehyde-treated films, which are heavily crosslinked, have high moduli and low rates of drug release. Films treated with chrome quickly become hydrated in solution and have low moduli and very rapid drug release characteristics. 

The collagen shield, fabricated from procine scleral tissue, is a spherical contact lens-shaped film whose thickness can be made to vary from 0.027 to 0,071 mm. It has a diameter of 14.5 mm and a base curve of 9 mm. Once the shield is hydrated by tear fluid and begins to dissolve, it softens and conforms to the corneal surface. Dissolution rates can be varied from 2 to as long as 72 hr by exposing the shields to ultraviolet radiation in order to achieve varying degrees of crosslinking. 

Mechanism of Action Lactic acid is an alpha-hydroxy acid that influences hydration, decreases corneocyte cohesion, reduces excessive epidermal keratinlzation in hyper-keratotic conditions, and induces synthesis of mucopolysaccharides and collagen In photodamagedskin. The exact mechanism is not known TherapeuticEffect Increases hydration of the skin. 

Sung N-H (1972) Structure and properties of collagen and gelatin in the hydrated and anhydrous solid state. ScD Thesis, Massachusetts Institute of Technology, Cambridge, MA... 

These vessels end in arcade-like structures at the limbus. The corneal stroma is made of three different main layers that differ in density of collagen and type of packing. The Bowman s membrane of the anterior stroma is part of the basal membrane of the corneal epithelium and accounts for 5% of the thickness of the central 500-600 pm cornea. The corneal stroma consists of highly ordered, horizontally organized and noninterconnected coUagen I and X fibriUae that are kept in a hydrated state with a water content of 72-78% and an osmolarity of 420 mOsmol/kg [1]. 

Hydroxypyridine crosslink in collagen 434 D-10-Hydroxystearate from hydration of oleic acid 688... 

Mrevlishvili189 gave the following enthalpy differences for the helix-coil transfer of collagen fibre - coils/solution (5 kcal/mole) coils/solution - helix/solution (—5.5 kcal/mole) helix/solution - helix/fibre (0.5 kcal/mole). The following table gives the differences between the hydration water of native and denaturated protein181,188> ... 

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