The efficiency of X-ray microanalysis in low-vacuum scanning electron microscope: deposition of calcium on the surface of implanted hydrogel intraocular lens (IOL).

To examine the calcification of implanted hydrogel IOL by X-ray microanalysis, we compared conventional transmission electron microscopy (TEM) with low-vacuum scanning electron microscopy (SEM). We also compared metal coating with non metal coating in low-vacuum SEM. Calcification of IOL showed deposits which were located in the superficial substance of lens. In conventional TEM and X-ray microanalysis, calcium, phosphate and silicon were detected in the deposits. In low-vacuum SEM, the deposits detected in metal coating were calcium, phosphorus, sodium and magnesium, but not silicon. However, in non metal coating, the deposits contained not only calcium, phosphorus, silicon, sodium and magnesium, but also fluoride, aluminum and argentums. It was concluded that in conventional TEM where a specimen is fixed and dehydrated in ethanol, various elements leak out. On the other hand, when a specimen is coated with carbon and gold palladium for SEM, light elements might not be detected in X-ray microanalysis. Low-vacuum SEM preparation does not need metal coating and low-vacuum SEM appears to provide a highly efficient method for X-ray microanalysis.

Age-related changes of human lens epithelial cells in vivo.

We examined the density and morphology of lens epithelial cells (LECs) in vivo in a group of normal volunteers and cataract patients by using a newly developed noncontact specular microscope. There was a statistically significant decrease in the cell density of LECs in a group of cataract patients over the age of 80 years. The coefficient of variation of the cell area and the number of large black spots that were observed in the enhanced specular images were not related to aging or cataract formation. Our data indicate that the cell density of LECs decreases after reaching the age of 80, but cataract formation does not affect the cell density or the coefficient of variation of the cell area until the age of 80.

The effects of extracellular matrix on cell attachment, proliferation and migration in a human lens epithelial cell line.

Lens capsule consists of several kinds of extracellular matrix (ECM) which may play an important role in cell attachment, migration and proliferation of lens epithelial cells as a basement membrane. We have investigated the effects of ECM on cell attachment, proliferation and migration in a human lens epithelial (HLE) cell line. The HLE cell line, SRA 01/04, which was transfected with large T-antigen of SV40 was cultured in the absence of serum. Culture plates were coated with human type IV collagen, laminin or fibronectin. The number of cells were counted at 30-180 min and 3, 5 and 7 days of culture. The rate of BrdU incorporation was measured to study the cell proliferation. The cell migration was measured 1, 3, 5 and 7 days after seeding cells. Integrins, the receptors of ECM, were also detected using antibodies for the cell membrane antigens (CD49b, CD49c, CD49e) by an immunohistochemical method. Although less than 10% of cells attached to the non-coated plate and 50-60% of cells attached to the ECM-coated plates, there was no difference of cell attachment among each ECM used. The cell attachment was almost complete during the first 30 min of culture. Cell proliferation was not enhanced, but cell survival was aided by culture on the ECM components for up to 7 days. The area of cell attachment enlarged on the ECM-coated plates, whereas no migration was observed on the non-coated plate. These data indicate that ECM is the essential factor for cell attachment and increases migration of HLE cells.