During syneresis bound water is released and becomes free water. irreversible syneresis has been observed in aging lens and vitreous with the consequence of altering the mechanical properties.in the lens syneresis changes also the optical properties causing turbidity. A reversible syneresis effects the activity of the water in the tissues and thus the colligative properties. Such reversible syneresis have been observed in our preliminary study in bovine as well in monkey lenses at extreme pressures (0, l and 2 atm). If this observation could be repeated at pressure in small increments near l atm, it may indicate that syneresis is a fast and energetically least expensive response to change in stresses which are present during accommodation. The proposed study tries to verify this in rhesus monkey lenses using differential scanning calorimetry and thermogravimetric analysis to obtain freezable water/nonfreezable water (FW/NFW) ratio change as a function of applied pressures. The study then will be extended to human lenses of different age. Since the FW/NFW experiment requires interruption at the and of each applied condition, we plan to investigate if by FT-IR difference spectra we could detect the same syneretic changes in a cyclical process. Finally, we plan to study FW/NFW ratio in human vitreous as a function of pressure. If pressure dependent irreversible syneresis exists in the vitreous, it may provide a link between glaucoma and vitreal degeneration.
| Bettelheim, Frederick A; Lizak, Martin J; Zigler Jr, J Samuel (2003) Syneretic response of aging normal human lens to pressure. Invest Ophthalmol Vis Sci 44:258-63 |
| Bettelheim, Frederick A; Lizak, Martin J; Zigler Jr, J Samuel (2002) Relaxographic studies of aging normal human lenses. Exp Eye Res 75:695-702 |
| Neal, R; Zigler Jr, J S; Bettelheim, F A (2001) On the equilibrium between monomeric alpha-lactalbumin and the chaperoning complex of alpha-crystallin. Biochem Biophys Res Commun 280:14-8 |
| Bettelheim, F A; Lizak, M J; Zigler Jr, J S (2001) NMR relaxation studies of syneretic response to pressure change in bovine lenses. Curr Eye Res 22:438-45 |
| Bettelheim, F A; Mofunanya, A (2001) Syneretic response to pressure in bovine and rhesus monkey vitreous. Exp Eye Res 73:133-6 |
| Bettelheim, F A; Zigler Jr, J S (1999) Pressure-induced syneretic response in rhesus monkey lenses. Invest Ophthalmol Vis Sci 40:1285-8 |
| Bettelheim, F A; Ansari, R; Cheng, Q F et al. (1999) The mode of chaperoning of dithiothreitol-denatured alpha-lactalbumin by alpha-crystallin. Biochem Biophys Res Commun 261:292-7 |
