The findings suggest that chronic occupational exposure to urban pollutants reduces resistance to physical effort and increases the risk of cardiovascular and respiratory changes including slight hypoxemia.

After lentectomy of larval Xenopus laevis, the outer cornea undergoes tissue transformation resulting in formation of a new lens. This lens regeneration is triggered and sustained by neural retina. In the present study, lens-forming transformation of the outer cornea was completed in vitfo when the outer cornea was cultured within the lentectomized eye-cup. Well-differentiated lens fiber cells, which showed positive immunofluorescence for total crystallins, were also formed when the outer cornea was cultivated with the retina. No lens tissue was formed when the cornea was cultured alone. Lens-forming transformation, originating from the cornea three and five days after lentectomy, completely regressed when the tissue was isolated in vitro. Fom the present and previous findings, we concluded that, the interaction of corneal cells with the retina plays a decisive role in lens regeneration in situ.

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