Eye injuries from traditional sports in Aosta Valley.

We reviewed the records of the patients hospitalised for eye injuries in Aosta Valley between January 1976 and June 1993. Eye injuries from traditional regional sports accounted for 27 cases (41.5% of all ocular sport injuries), of which 21 (77.8%) occurred during the game 'tsan', the most popular one. Injuries led to legal blindness in 3 (11.1%) cases and to a permanent visual loss in 2 (7.4%). Although our data do not allow to assess either a significantly higher incidence or severity of eye injuries from Aosta Valley regional games as compared with other sports, the possibility of severe trauma with visual loss suggests to extend the use of protection devices.

[Complications of disposable extended-wear contact lenses. Apropos of 6 cases]. / Complications des lentilles cornéennes jetables en port prolongé. A propos de six cas.

We report six cases of corneal complications observed in disposable extended-wear contact lens users: two corneal ulcers, one superficial infiltrate, two punctate keratitis with subepithelial infiltrates and one superficial punctate keratitis. In four cases a bacterial etiology was confirmed. Disposable contact lenses are not complication-free. In our series, complications were favoured or provoked by incorrect use in most cases. Other possible risk factors include poor hygiene during lens manipulation, damage to the corneal epithelium during lens exchange or lens wear, use of contaminated lubricant eyedrops, relative corneal hypoxia during overnight wear or in the case of improper fitting. Correct and adequate patient information is therefore essential to ensure that these lenses constitute a safe choice.

Requirement for olfactory axons in the induction and stabilization of olfactory glomeruli in an insect.

The role of antennal sensory axons in the induction and stabilization of olfactory glomeruli has been explored in the moth Manduca sexta. First, we asked the question: how many axons are necessary to induce glomerulus formation within the first-order olfactory neuropil of the brain? Axons from as few as 10 of the normal 70-80 repeating antennal segments were sufficient to induce glomeruli. However, there was a dose dependence in the number of glomeruli that developed in partially innervated lobes. When only 11 segments of the antenna were allowed to provide innervation to the lobe, only 37 of the normal 59 +/- 2 glomeruli developed; over 20 segments were necessary to induce the normal number of glomeruli. In a second set of experiments, we asked: for how long must antennal axons be present to stabilize newly formed glomeruli? We found that antennal axons must be intact for at least 2 to 4 stages (roughly equivalent to 2 to 4 days) for glomeruli to be stable even if the axons are subsequently severed. This finding, taken in the light of other recent findings in our laboratory, suggests that the formation of synapses may be a crucial element in the stabilization of glomerular structure. All together, the results of the present study indicate that induction and stabilization of glomeruli are separable events with different underlying cellular bases.

A fluorimetric study of the lanthanides binding to concanavalin A.

The binding of Tb3+ and other lanthanides to Con A has been studied by sensitized Tb3+ luminescence, by quenching of intrinsic fluorescence and by activity measurements. In all the experimental conditions tested, it was found that holo and apo Con A bind lanthanide ions at a site different from the binding sites of the constitutive metals, Mn2+ and Ca2+. The bound lanthanide did not affect the saccharide binding ability and the hemoagglutinating ability of Con A. The intrinsic fluorescence of Con A is quenched by the binding of Tb3+ and Gd3+. The same quenching is obtained by shifting the pH of Con A from pH 6.5 to 4.5. It is proposed that H+ and Ln3+ completely quench a tryptophan, perhaps the residue 88 or 182.

A reinvestigation on the quaternary structure of ascorbate oxidase from Cucurbita pepo medullosa.

The optical properties, copper content, catalytic activity and quaternary structure of many preparations of ascorbate oxidase purified with two different methods were examined. Fresh samples appeared identical and were characterized by optical ratios A280/A610 = 25 +/- 1 and A330/A610 = 0.8 +/- 0.05, by specific activity toward ascorbate of 3.48 +/- 0.05 mol g-1 min-1 and by a copper content of 8 +/- 0.3 mol/145 000 Mr. The enzyme is composed of two non-covalently linked subunits of slightly different molecular mass (75 000 and 72 000 respectively). These subunits cannot be further resolved by reduction of disulfide bonds. Proteolytic cleavage of the protein chains was observed during purification and storage in the absence of the protease inhibitor 6-amino caproic acid. Ascorbate oxidase exists as a monomer at neutral pH and undergoes reversible association into higher molecular weight species at slightly acid pH values. Association is not accompanied by spectroscopic or catalytic changes.