Lens cell development

ADPRT and DNA Strand Breaks in Lens Cell Development... 

In biological systems molecular assemblies connected by non-covalent interactions are as common as biopolymers. Examples arc protein and DNA helices, enzyme-substrate and multienzyme complexes, bilayer lipid membranes (BLMs), and aggregates of biopolymers forming various aqueous gels, e.g, the eye lens. About 50% of the organic substances in humans are accounted for by the membrane structures of cells, which constitute the medium for the vast majority of biochemical reactions. Evidently organic synthesis should also develop tools to mimic the Structure and propertiesof biopolymer, biomembrane, and gel structures in aqueous media. 

We developed an experimental procedure that can be applied to highly viscous polymer blends. In the DSM micro-extruder [6], polymers are blended in the melt, at the desired temperature and pressure, and injected into a small capillary tube which is immediately sealed with a floating plug. This capillary cell is placed in a small window autoclave and a laser beam enters the capillary cell at the lens-shaped bottom end. The intensity of the light scattered by the polymer system is recorded at two scattering angles (as a function of pressure and temperature). 

With the development of neutral hydrophilic methacrylates in Prague, originally for contact lens applications in the early 60 s113>, considerable interest was generated in the application of these materials in the cardiovasular environment. The qualitative argument was that such soft, water-rich surfaces must be relatively non-traumatic to proteins and cells. The development of neutral hydrophilic polysaccharide-based particles for protein chromatography in the late 60 s provided evidence that such surfaces do indeed show minimal binding of proteins. 

Micromass has developed a potentially powerful new technique that eliminates many of these molecular interferences and also removes ions with an energy that differs from that of the analyte, such as components of the Ar support gas. This has a dramatic effect on the performance of the instrument. The technique deploys a hexapole ion lens (Szabo, 1986) located behind the skimmer cone and surrounded by a gas cell (Fig. 8.5). The hexapole uses a hexagonal array of rods between which a 400-V rf field is applied, confining the ions of interest to stable trajectories be-... 

With the pupil dilated, the area of posterior iris surface in contact with the anterior lens capsule decreases. Moreover, the cycloplegia produced by atropine is of additional value in reducing both the thickness and convexity of the lens. If posterior synechiae should develop even when the pupil is dilated, there is less chance of iris bombe. Atropine may also help decrease the excessive permeability of the inflamed vessels and thereby reduce cells and protein in the anterior chamber (aqueous flare). 

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