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H-1-Nmr and Calorimetric Measurements on Rabbit Eye Lenses

Gutsze, A. and Bodurka, J. and Robert, O. and Buntkowsky, G. and Limbach, H. H. (1995):
H-1-Nmr and Calorimetric Measurements on Rabbit Eye Lenses.
50, In: Zeitschrift Fur Naturforschung C-a Journal of Biosciences, (5-6), pp. 410-418, [Online-Edition: http://apps.webofknowledge.com/full_record.do?product=WOS&se...],
[Article]

Abstract

The dynamic properties of water molecules in the rabbit lens were studied by proton nuclear magnetic resonance line shape analysis, measurements of relaxation times as a function of temperature and calorimetric measurements. The experiments prove, as already suggested by other authors, that there are two types of water in the lens of rabbit eyes, namely bound unfreezable hydration water and bulk freezable water. Line shape analysis and relaxometry showed, that this two types of water exist in two different environments, which may be identified as the nucleus and the cortex of the lens. The line shape analysis showed furthermore that water molecules in the rabbit lens has a common spin lattice relaxation time (T-1), but two different transverse relaxation times (T-2A and T-2B). The tentative model of fast water exchange on the T-1 time scale and slow water exchange on the T-2 time scale, was used to explain experimental proton relaxation data of the rabbit lens. An estimation for this exchange rate k(ex) by comparing it to the relaxation times is given (T-1(-1) much less than k(ex) much less than T-1(-1)). It has also been shown by a calorimetric measurements that the lenses can be easily undercooled to temperatures well below the freezing point of water. The achievable maximum undercooling temperature of the lens is a function of the cooling rate K-C, therefore it has to be considered as an experimentally adjustable parameter which is not characteristic for the investigated sample. Thus it must be noted that any previous discussions about the specific value of the temperature of water crystallisation in biological systems need to be carefully reconsidered.

Item Type: Article
Erschienen: 1995
Creators: Gutsze, A. and Bodurka, J. and Robert, O. and Buntkowsky, G. and Limbach, H. H.
Title: H-1-Nmr and Calorimetric Measurements on Rabbit Eye Lenses
Language: English
Abstract:

The dynamic properties of water molecules in the rabbit lens were studied by proton nuclear magnetic resonance line shape analysis, measurements of relaxation times as a function of temperature and calorimetric measurements. The experiments prove, as already suggested by other authors, that there are two types of water in the lens of rabbit eyes, namely bound unfreezable hydration water and bulk freezable water. Line shape analysis and relaxometry showed, that this two types of water exist in two different environments, which may be identified as the nucleus and the cortex of the lens. The line shape analysis showed furthermore that water molecules in the rabbit lens has a common spin lattice relaxation time (T-1), but two different transverse relaxation times (T-2A and T-2B). The tentative model of fast water exchange on the T-1 time scale and slow water exchange on the T-2 time scale, was used to explain experimental proton relaxation data of the rabbit lens. An estimation for this exchange rate k(ex) by comparing it to the relaxation times is given (T-1(-1) much less than k(ex) much less than T-1(-1)). It has also been shown by a calorimetric measurements that the lenses can be easily undercooled to temperatures well below the freezing point of water. The achievable maximum undercooling temperature of the lens is a function of the cooling rate K-C, therefore it has to be considered as an experimentally adjustable parameter which is not characteristic for the investigated sample. Thus it must be noted that any previous discussions about the specific value of the temperature of water crystallisation in biological systems need to be carefully reconsidered.

Journal or Publication Title: Zeitschrift Fur Naturforschung C-a Journal of Biosciences
Volume: 50
Number: 5-6
Uncontrolled Keywords: h-1 nmr rabbit lens relaxation measurements line shape water nuclear-magnetic-resonance protein solutions relaxation-times transverse relaxation cross-relaxation molecular theory tissue water temperature
Divisions: 07 Department of Chemistry
07 Department of Chemistry > Physical Chemistry
Date Deposited: 27 Oct 2014 20:50
Official URL: http://apps.webofknowledge.com/full_record.do?product=WOS&se...
Additional Information:

Rf993 Times Cited:8 Cited References Count:35

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