[Therapy of allergic conjunctivitis]. / Az allergiás conjunctivitisek terápiája.

Among the several eye diseases (or diseases involving the eye) based on hypersensitivity reactions, the most frequent is allergic conjunctivitis. Recently six types of allergic conjunctivitis/keratoconjunctivitis are distinguished: 1. seasonal, 2. perennial, 3. vernal, 4. giant papillary, 5. atopic and 6. of contact origin. Their treatment is generally local. In the most frequent seasonal ("hay fever") and perennial forms the elimination of the allergen or when it is impossible antihistamines (with or without vasoconstrictors), "weak" steroids or hyposensitisation are offered. In vernal and atopic keratoconjunctivitis mast cell stabilizers are the most effective, with special effect of lodoxamide in the vernal type. In giant papillary and contact allergic inflammations the elimination of the causative agent is the first method of choice. In resistant cases "strong" steroids, in extreme forms immunosuppressive, cytostatic and systemic treatment may become necessary. The paper gives a review of currently applied medicines (mainly eyedrops) and other methods of treatment, and includes therapeutic principles applying to various forms of allergic conjunctivitis.

Scleral reinforcement in progressive myopia and intraoperative ultrasound control of the cadaver fascia lata strip.

Scleral reinforcement (sustentaculum sclerae) is one of the operations against myopia. During the progression of myopia the eye grows. The chorioretinal layer can only moderately follow the expansion of the sclera, and mostly this is the cause of the complications that can cause permanent visual acuity decrease. The aim of the operation is to strengthen the posterior part of the sclera by implantation of a cadaver fascia lata strip, that slows down or stops the expansion of the eyeball, and this way prevents the development of complications. At our Department we perform the Snyder-Thompson technique. Between 1984 and 1994 343 operations were performed at our Department. We followed up the changes of the axial lengths by ultrasound (A-mode) examinations. The axial length decreased in 43.7% remained unchanged in 22.2% and increased in 34.1% of the cases. We controlled the location of the strip intra- and postoperatively with B-mode ultrasound. Nowadays scleral reinforcement is still the only possibility to stop or slow down the expansion of the eyeball in cases of progressive high myopia.

Localization of transglutaminase in human lenses.

Transglutaminase activity has been detected in the lenses of laboratory animals and in human cataracts. However, its distribution in the lens tissue has not been investigated. Using a monoclonal antibody against tissue transglutaminase, we showed by Western blotting and immunoabsorption that transglutaminase of normal human lens is immunologically related to tissue transglutaminase but has a slightly higher M(r) than the latter enzyme. Using monoclonal or polyclonal antibody against tissue transglutaminase, lens transglutaminase was localized to the epithelial cell layer on the anterior lens surface and to a thin stripe between the capsule and the peripheral cortex on the posterior surface. Lens fibers were not stained with the antibodies. Factor XIII, another transglutaminase, could not be detected in the lens tissue. The localization of transglutaminase in the lens suggests that lens transglutaminase is synthesized in the epithelial cells and secreted into the virtual space between the capsule and the peripheral cortex spreading all around the lens substance.

Transglutaminase activity in normal human lenses and in senile cataracts.

Transglutaminase, the main function of which is to crosslink peptide chains through isopeptide bonds, has been detected in the lens of laboratory animals and in human cataracts and has been implicated in cataractogenesis. The transglutaminase activity has been estimated by measuring the amount of 3H-putrescine incorporation into dimethyl-casein of clear noncataractous human lenses and by comparing it with that of cataracts of different grades. Both the total and specific transglutaminase activity of highly cataractous lenses were less than those of normal lenses. During the progression of cataract (slightly moderately, and highly cataractous groups were compared), there was a substantial decrease in transglutaminase activity. In contrast to our findings, an increased transglutaminase activity has been reported in the lens of rats and mice with cataract mutation. This discrepancy is probably due to the different mechanisms involved in the development of human senile cataract and cataract in mutated laboratory animals.

Non-proteolytic activation of cellular protransglutaminase (placenta macrophage factor XIII).

Plasma Factor XIII is a zymogen (plasma protransglutaminase) with the tetrametric structure A2B2, whereas the cellular protransglutaminase, i.e. Factor XIII in the platelet and monocyte/macrophage, consists exclusively of A subunits (A2). It is generally accepted that at Ca2+ concentrations comparable with that in plasma the proteolytic removal of an N-terminal activation peptide is the prerequisite for the Ca2(+)-induced formation of a catalytically active configuration of subunit A. In this study it was demonstrated that at high concentrations NaCl or KCl induced a non-proteolytic activation of cellular (placental macrophage) but not plasma protransglutaminase. The activation depended on time and salt concentration, and Ca2+, in the range 0-20 mM, greatly enhanced the activation process. At 1.25 M-NaCl maximal activation occurred within 60 min in the presence of 2 mM-CaCl2, and even at physiological NaCl concentration a slow progressive activation could be observed in the presence of Ca2+. The specific activity of salt-activated Factor XIII was 1.5-2.0-fold higher than that obtained after thrombin activation. The non-proteolytic activation of cellular protransglutaminase was abolished by the addition of subunit B of plasma Factor XIII in stoichiometric amount, which suggests that (one of) the physiological function(s) of the B subunit in plasma Factor XIII is to prevent the slow spontaneous activation of A subunit that would occur in a plasmatic environment.