Inhibition of rat lens aldose reductase by bendazac-L-lysine salt.

Authors describe the in vitro effect of bendazac-L-lysine salt on the activity of enzyme aldose reductase from rat lens. In the presence of bendazac the activity of the tested enzyme was inhibited. Lineweaver-Burk plot demonstrated that the inhibition was noncompetitive. The possible curative effects on diabetic cataract together with a better way of administration are pointed out.

Effect of topical glucocorticoid administration on the protein and nonprotein sulfhydryl groups of the rabbit lens.

The effects of topical administration of glucocorticoids on rabbit lenses are described. Animals were divided into three groups. The first group (A) served as control, the second (B) and the third (C) group were treated with betamethasone and fluorometholone, respectively. After 40 days of treatment there was a significant fall in the levels of nonprotein sulfhydryl (-SH) groups (group A: 3.82 +/- 0.21; group B: 2.61 +/- 0.11; group C: 1.93 +/- 0.13 mumol/lens) and of protein -SH groups (group A: 8.215 +/- 1.023; group B: 4.120 +/- 0.631; group C: 4.068 +/- 0.538 mumol/lens). Also ascorbic acid levels showed a significant decrease both in lens and in aqueous humor. No differences were noted in the reduced glutathione content in aqueous humor. The fall in nonprotein and protein -SH could be the first event in the well-known biochemical changes that occur in steroid-induced cataract. The mechanism underlying steroid-induced damage could be due to a conformational change of lens crystallins which results in an unmasking of -SH groups with a consequent increased susceptibility to oxidation. The decrease of ascorbic acid should represent an effect of the fall in the glutathione system. Lastly, it is hypothesized that the protective effect exerted by some substances, such as vitamin E and ascorbic acid, occurs by counteracting this oxidation.

Behçet's disease: an unusual case with bilateral obliterating retinal panarteritis and ischemic optic atrophy.

Report of an unusual case of Behçet's disease with bilateral obliterating retinal panarteritis and ischemic optic atrophy. The rarity of the primary optic nerve involvement and chiefly the exceptional full acute bilateral occlusion of the retinal arteries are emphasized. This ophthalmoscopic picture is further clinical evidence for the major importance of the vascular involvement in the pathogenesis of Behçet's disease.

Quantification and measurement of human lens opacities using the lens opacity meter.

Lens opacity was quantified in 85 cataractous patients, using a new instrument: the lens opacity meter 701 (LOM; Interzeag, Schlieren, Switzerland). Cataracts were classified as nuclear, cortical, subcapsular and mixed forms. Sensitivity, specificity and reproducibility of the results were evaluated by statistical analysis. Visual acuity was correlated with LOM values in patients with nuclear and mixed cataracts. Moreover, the instrument gave a good degree of reproducibility only in patients who presented these forms of lens opacities. Our findings demonstrate that the LOM 701 is able to detect and to measure only lens opacities which affect the central area of the lens.

Systemic and ocular effects of alpha 2-adrenergic stimulating and beta 2-blocking agents.

The effects of alpha 2-adrenergic stimulating agents (clonidine and guanabenz) and beta-adrenolytic agents (atenolol and propranolol) on the systemic arterial pressure, heart-rate, blood glucose level and intraocular pressure, as well as on the concentrations of glucose, Na+, K+ and Ca++ in the lens and aqueous and vitreous humours, are evaluated in the rabbit. alpha 2-adrenergic stimulating agents cause a significant increase of the glucose concentration in the blood, lens, aqueous and vitreous humours; whereas the beta-adrenolytic agents cause insignificant effects. Neither of the two drugs alters the concentration of Na+, K+ and Ca++ in the lens and aqueous and vitreous humours.