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The effect of paraformaldehyde fixation and PBS storage on the water content of the human lens.

Augusteyn RC, Vrensen G, Willekens B - Mol. Vis. (2008)

Bottom Line: It is assumed that this does not alter the properties being examined.Comparison of literature data for a fixed eight-year-old lens with those for an unfixed seven-year-old lens indicated that the decrease in wet weight was due mainly to a loss of water from the cortex, which resulted in virtual disappearance of the water/protein gradient and the formation of a plateau containing 58% water in over 90% of the lens.In addition, prolonged storage of a lens in PBS will result in substantial water uptake, which may affect measurements of their dimensions and optical properties.

View Article: PubMed Central - PubMed

Affiliation: Vision Cooperative Research Centre, Sydney, Australia and Department of Biochemistry and Molecular Biology, La Trobe University, Bundoora Australia. raugustn@bigpond.net.au

ABSTRACT

Purpose: Fixation and phosphate buffered saline (PBS) storage are frequently used before studies of the morphological, biochemical, and optical properties of the human lens begin. It is assumed that this does not alter the properties being examined. The present study was undertaken to determine the effects of fixation and PBS storage on the human lens wet weight.

Methods: Human donor lenses were incubated in a buffered paraformaldehyde (PF) solution or in PBS and their wet weights were monitored for up to 44 and 13 days, respectively.

Results: PF fixation resulted in a large decrease in wet weight, averaging 25%+/-2.3% at 30 days for 14 human donor lenses, aged 49-80 years. The loss was essentially complete by 21 days. Out of the 10 lenses, aged 52-71 years, which were incubated in PBS alone, six of them increased in weight by an average of 38% over 13 days and four ruptured within four days. Comparison of literature data for a fixed eight-year-old lens with those for an unfixed seven-year-old lens indicated that the decrease in wet weight was due mainly to a loss of water from the cortex, which resulted in virtual disappearance of the water/protein gradient and the formation of a plateau containing 58% water in over 90% of the lens.

Conclusions: Fixation substantially alters the amount and distribution of water in the human lens. Caution should be exercised when interpreting data on water and protein distributions as well as cell dimensions obtained with lenses which have been fixed. In addition, prolonged storage of a lens in PBS will result in substantial water uptake, which may affect measurements of their dimensions and optical properties.

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Related in: MedlinePlus

The distribution of water along the sagittal axis in fixed and unfixed human lenses. Comparison of the distributions of water along the sagittal axis in an unfixed seven-year-old lens (green diamond), which was calculated from the RI gradient obtained with MRI [12], and in a fixed eight-year-old lens (red diamond) as determined by the use of Raman microspectroscopy [5] is shown. The dimensions were normalized to eliminate differences in the thickness of the lenses due to possible shrinkage of the fixed lens.
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f4: The distribution of water along the sagittal axis in fixed and unfixed human lenses. Comparison of the distributions of water along the sagittal axis in an unfixed seven-year-old lens (green diamond), which was calculated from the RI gradient obtained with MRI [12], and in a fixed eight-year-old lens (red diamond) as determined by the use of Raman microspectroscopy [5] is shown. The dimensions were normalized to eliminate differences in the thickness of the lenses due to possible shrinkage of the fixed lens.

Mentions: To determine from where the water was lost, the water distribution in a fixed eight-year-old lens described by Siebinga et al. [5] was compared with that calculated from the refractive index gradient observed in an unfixed seven-year-old lens [12]. The distributions along the sagittal (optical) axes are shown in Figure 4. Essentially the same differences were found for the equatorial axis.


The effect of paraformaldehyde fixation and PBS storage on the water content of the human lens.

Augusteyn RC, Vrensen G, Willekens B - Mol. Vis. (2008)

The distribution of water along the sagittal axis in fixed and unfixed human lenses. Comparison of the distributions of water along the sagittal axis in an unfixed seven-year-old lens (green diamond), which was calculated from the RI gradient obtained with MRI [12], and in a fixed eight-year-old lens (red diamond) as determined by the use of Raman microspectroscopy [5] is shown. The dimensions were normalized to eliminate differences in the thickness of the lenses due to possible shrinkage of the fixed lens.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2254961&req=5

f4: The distribution of water along the sagittal axis in fixed and unfixed human lenses. Comparison of the distributions of water along the sagittal axis in an unfixed seven-year-old lens (green diamond), which was calculated from the RI gradient obtained with MRI [12], and in a fixed eight-year-old lens (red diamond) as determined by the use of Raman microspectroscopy [5] is shown. The dimensions were normalized to eliminate differences in the thickness of the lenses due to possible shrinkage of the fixed lens.
Mentions: To determine from where the water was lost, the water distribution in a fixed eight-year-old lens described by Siebinga et al. [5] was compared with that calculated from the refractive index gradient observed in an unfixed seven-year-old lens [12]. The distributions along the sagittal (optical) axes are shown in Figure 4. Essentially the same differences were found for the equatorial axis.

Bottom Line: It is assumed that this does not alter the properties being examined.Comparison of literature data for a fixed eight-year-old lens with those for an unfixed seven-year-old lens indicated that the decrease in wet weight was due mainly to a loss of water from the cortex, which resulted in virtual disappearance of the water/protein gradient and the formation of a plateau containing 58% water in over 90% of the lens.In addition, prolonged storage of a lens in PBS will result in substantial water uptake, which may affect measurements of their dimensions and optical properties.

View Article: PubMed Central - PubMed

Affiliation: Vision Cooperative Research Centre, Sydney, Australia and Department of Biochemistry and Molecular Biology, La Trobe University, Bundoora Australia. raugustn@bigpond.net.au

ABSTRACT

Purpose: Fixation and phosphate buffered saline (PBS) storage are frequently used before studies of the morphological, biochemical, and optical properties of the human lens begin. It is assumed that this does not alter the properties being examined. The present study was undertaken to determine the effects of fixation and PBS storage on the human lens wet weight.

Methods: Human donor lenses were incubated in a buffered paraformaldehyde (PF) solution or in PBS and their wet weights were monitored for up to 44 and 13 days, respectively.

Results: PF fixation resulted in a large decrease in wet weight, averaging 25%+/-2.3% at 30 days for 14 human donor lenses, aged 49-80 years. The loss was essentially complete by 21 days. Out of the 10 lenses, aged 52-71 years, which were incubated in PBS alone, six of them increased in weight by an average of 38% over 13 days and four ruptured within four days. Comparison of literature data for a fixed eight-year-old lens with those for an unfixed seven-year-old lens indicated that the decrease in wet weight was due mainly to a loss of water from the cortex, which resulted in virtual disappearance of the water/protein gradient and the formation of a plateau containing 58% water in over 90% of the lens.

Conclusions: Fixation substantially alters the amount and distribution of water in the human lens. Caution should be exercised when interpreting data on water and protein distributions as well as cell dimensions obtained with lenses which have been fixed. In addition, prolonged storage of a lens in PBS will result in substantial water uptake, which may affect measurements of their dimensions and optical properties.

Show MeSH
Related in: MedlinePlus