Changes of corneal optical properties after UVB irradiation investigated spectrophotometrically

Ozone depletion leads to an increase in UV rays of solar radiation reaching the surface of the Earth which is harmful to biological systems. Of the eye, the cornea is directly open to increased amount of UV rays of which mainly UVB rays are capable to induce reactive oxygen species damaging the cells. Previous studies showed that the irradiation of the cornea with UVB rays leads to morphological as well as metabolic disturbances of the cornea. Also, corneal hydration and corneal light absorption are increased after UVB rays. These changes were observed after five days of repeated irradiation of the cornea with UVB rays. The aim of the present paper was to examine how early the changes of corneal hydration and light absorption occur after UVB irradiation. The rabbit corneas were irradiated with UVB rays for one, two, three or four days. Corneal light absorption was examined spectrophotometrically and corneal hydration measured by pachymeter (as corneal thickness). Results show that changes of corneal hydration and light absorption appear early after UVB irradiation and increase along with the number of irradiations. In conclusion, irradiation of the rabbit cornea with UVB rays leads to harmful changes of its optical properties.

Antileukotrienic N-arylethyl-2-arylacetamides in the treatment of ulcerative colitis

A series of arylacetic acid derivatives bearing methyl(arylethyl)amino groups were prepared and their antileukotrienic activities involving LTB(4) were evaluated. Regression analysis has shown a strong dependence of these activities on lipophilicity for both LTB(4) receptor binding and inhibition of LTB(4) biosynthesis; parabolic relationships were derived. The values of slopes of the ascending linear parts of these dependences indicate various types of hydrophobic binding at the site of ligand interaction with relevant biomacromolecules. The anti-inflammatory effect of the compounds under study was also evaluated in three animal models of inflammation and their possible utilization in the treatment of ulcerative colitis (UC) was followed. The importance of antileukotrienic activities for the anti-inflammatory effect, especially in the model of UC was discussed, but further experiments are necessary to confirm the respective relations.

Nitric oxide synthase induction and cytotoxic nitrogen-related oxidant formation in conjunctival epithelium of dry eye (Sjögren's syndrome)

Until now, the expression and possible role of nitric oxide and nitrogen related oxidants in the human dry eye have not been investigated. Therefore, we examined immunohistochemically nitric oxide synthase isomers (NOS), enzymes generated nitric oxide, nitrotyrosine, a cytotoxic byproduct of nitric oxide and malondialdehyde, a byproduct of lipid peroxidation, in conjunctival epithelium of patients with dry eye, Sjögren's syndrome (SS). Moreover, in conjunctival epithelium of patients with dry eye (SS) the immunohistochemical staining of some pro-inflammatory cytokines was demonstrated: mature interleukin-1 beta (IL-1beta), interleukin 6 (IL-6), interleukin 8 (IL-8) and tumor necrosis factor alpha (TNF-alpha). Conjunctival epithelial cells were obtained by the method of impression cytology. Normal eyes served as controls. In contrast to the normal eyes where endothelial nitric oxide synthase (NOS3) as well as inducible nitric oxide synthase (NOS2) were only slightly expressed in conjunctival epithelium, in dry eye both NOS (mainly NOS2) were gradually expressed along the severity of dry eye symptoms which was in accord with pro-inflammatory cytokine immunodetection (IL-1beta, IL-6, IL-8, TNF-alpha) in dry eye conjunctival cytology samples. This was in contrast to normal eyes where the staining of pro-inflammatory cytokines was weak or completely absent. Peroxynitrite formation (demonstrated by nitrotyrosine residues) and lipid peroxidation (evaluated by increased malondialdehyde staining) were also found in conjunctival epithelium of dry eye with highly pronounced symptoms of dryness. In conclusion, results point to the suggestion that reactive nitrogen species are involved in the pathogenesis or self-propagation of autoimmune dry eye (SS).

[Personal experience in treatment of glaucoma in children with the Sturge-Weber syndrome]

The authors give an account of their experience with the treatment of secondary glaucoma in children with Sturge-Weber's syndrome, followed up on a long-term basis (mean follow up period 6 years). Sixteen eyes of 13 children, mean age 10.5 years during the last check-up were treated: four eyes by medicamentous treatment, 12 eyes were operated. A total of 27 operations were performed: 13x cyclocryocoagulation, 11x trabeculectomy and including peroperative administration of 5-fluorouracil in 3 cases, 2x trabeculotomy and 1x laser trabeculoplasty. The criterium of therapeutic success is an intraocular pressure < or = 21 torr and a concomitant drop of the tension by at least 30% and absence of progression on the papilla or perimeter. In the whole group glaucoma is compensated in 11 eyes (68.8%). The most frequent complication was choroid ablation after filtration surgery (6x). It developed practically only in older children. In two patients bilateral glaucoma was observed despite unilateral naevus flammeus. Therefore it is necessary to check always both eyes.

[Results of treatment of glaucoma associated with aniridia]

The authors evaluate retrospectively the therapeutic results in secondary glaucoma with aniridia in 11 children (22 eyes) investigated since 1985. The mean age of the patients was 6.8 years. The examination under general anaesthesia was made in 10 children already during their first year and check-up examinations followed after 3-6 month intervals. Treatment of glaucoma was started by medicamentous therapy. If the effect was inadequate, cyclocryotherapy and trabeculectomy were used. Thirteen eyes are compensated by medicamentous treatment only, while surgical intervention was necessary in nine eyes of five children. A total of 20 operations were made, 12 times cyclocryotherapy and 8 times trabeculectomy, whereby the glaucoma is at present compensated in six operated eyes. A total of 19 eyes are compensated. The mean follow up period is 47 months in the operated patients and seven years in patients having medicamentous therapy. The analysis revealed that secondary glaucoma in aniridia can be compensated by mere medicamentous treatment for a number of years. If surgery is inevitable, cyclocryotherapy and trabeculectomy are only relatively successful.

[New approaches in clinical ophthalmology: UV absorbers and hindered amines covalently bound to contact lenses. Importance of enzyme histochemistry in studying their effectiveness in vivo]

UV absorbers developed by us are covalently bound in hydrophilic contact lenses. This is great advantage because UV absorbers cannot be diluted from contact lenses. In laboratory investigations and "in vivo" experiments it was found that contact lenses containing UV absorbents prevent the eye against the damaging effect of UV irradiation (UVA, UVB, UVC rays). The second new approach (mentioned in this paper) is the use of Hindered Amine Light Stabilizer (4-methakryloylamino-2,2,6,6-tetramethylpiperidine) covalently bound in the hydrophilic contact or therapeutic lenses--for the healing of the damaged eye. In laboratory measurements the cleavage of hydrogen peroxide (of various concentrations) by hindered amine light stabilizer was confirmed. In "in vivo" experiments it was examined histochemically and morphologically that Hindered Amines Light Stabilizer bound in contact lenses favourable influenced the healing of the damaged anterior eye segment of rabbits. The amount as well as enzyme activation (lysosomal hydrolases) of inflammatory cells was significantly reduced in the anterior eye segment. It is suggested that Hindered Amine Light Stabilizer reacts with reactive oxygen species (oxyradicals and hydrogen peroxide) present in the damaged anterior eye segment (e.g. released from inflammatory cells). During this reaction intermediate products appear and the resulting product is a nitroxide radical. All reaction products as well as resulting product are covalently bound in hydrophilic material. For the development and also evaluation of the efficacy of both new approaches perspective for the use in clinical ophthalmology, biochemical investigations and histochemical methods are employed. Enzyme histochemistry is very important for the evaluation of the efficacy of new therapeutic approaches "in vivo" and therefore the particular attention is devoted to it in this communication.

[Pars plana/plicata lensectomy with anterior vitrectomy in the treatment of complicated cataract in children]

Pars plana/plicata lensectomy with anterior vitrectomy was performed in a total of 16 eyes of 10 children with congenital cataract, microphthalmus, PHPV and other developmental anomalies and in three patients with complicated cataract due to chronic uveitis and in hydrophthalmus. The anatomical results of the operation are satisfactory, the functional results are limited in particular by the primary changes of the eyes and the child's age at extraction. An earlier diagnosis would be ensured by screening of the transparency of optic media in neonates.

[Extraocular changes in congenital aniridia]

The authors draw attention to possible extraocular changes in children with congenital aniridia. Of 31 investigated patients they were found in 5 children. Among these changes, because of its serious character, Wilms tumour holds the first place; it was found by the authors in two children. To ensure its early detection, the authors emphasize the necessity to dispensarize all children with congenital aniridia. Collaboration with an experienced X-ray specialist and child oncologist is essential. In addition to Wilms' tumour congenital aniridia can be associated with serious somatic developmental changes. The authors observed in one child and AGR triad and in two patients deformities of the skeleton of the head and lower extremities.

[Retinopathy of prematurity over 3 decades]

The authors give an account of 190 premature infants they treated in 1956-1988, suffering from retinopathy of prematurity--ROP, and for prolonged subsequent periods. As the head of the team followed up all the children, there is an integrated view of the problem. The birth weight of the infants was 640 g--1,900 g. From the total number 76.8% infants had a birth weight of 1,500 g or less, 13.7% had a birthweight of 1,000 g or less. Evidence of the increasing rate is provided by the number of patients treated since birth at the department for premature and pathological infants FNM as well as by the number of children admitted from other departments after development of ROP. In 1956-1970, i. e. in 15 years, the authors looked after 34 patients, in 1971-1988, i. e. in 18 years there were 156 children with ROP. In 1956-70 cases of ROP predominated which developed as a result of absolute or relative hypoxia. They were successfully treated by individually adjusted and carefully controlled oxygen therapy (6.9% blind children). In 1971-1975 the possibility to use this therapy declined briskly because after introduction of modern medical technique the number of findings suggesting a hyperoxic insult increased. At that time the results deteriorated greatly (50% blind children). In 1976-1980 the results were favourably influenced by individual dosage of oxygen therapy in all infants, based on regular monitoring of blood gases (10.5% blind children).(ABSTRACT TRUNCATED AT 250 WORDS)

[New analgesically active derivatives of 1-phenyl-5-mercaptotetrazole]

For the investigation of new anti-inflammatory drugs, 1-phenyl-5-mercaptotetrazole (I) was selected as the principal structure. The purpose itself lay in an alkylation of the mercapto group with different remainders. In some cases at the same time a substituent was introduced on the phenyl nucleus in position 1. An alkylation of 1-phenyl-5-mercaptotetrazole with ethyl bromacetate and a subsequent hydrolysis resulted in (1-phenyl-5-tetrazolylthio)acetic acid (II) as well as its chloride and hydrazide. The reaction of chloride with amino acids gave rise to amides III-VII. From hydrazide and phenylisocyanate, 4-chlorphenylisocyanate and phenylisothiocyanate, semicarbazides VIII and IX and thiosemicarbazide X were prepared. Furthermore, a reaction of substituted anilines and 2,3-expoxypropylchloride yielded the pertinent 3-anilino-2-hydroxypropylchlorides XX-XXIII, by which 1-phenyl-5-mercaptotetrazole in the form of the potassium salt was alkylated to compounds XIV-XIX. 1-Phenyl-5-mercaptotetrazole was also alkylated by 2-chlorethanol and the obtained 1-phenyl-5-(2-hydroxyethylthio)tetrazole was esterified by 4-phenylbenzoylchloride and 2-acetoxybenzoyl-chloride giving rise to esters XII and XIII. Finally, three compounds XXIV-XXVI, resulting from an alkylation of 1-phenyl or 1-allylmercaptotrazole by substituted 3-phenoxy-2-hydroxypropylchlorides. In all compounds an orientational acute toxicity higher than 1 g/1 kg p.o. was found. Pharmacological results are shown in Table 2. None of the above-mentioned compounds showed a significant anti-inflammatory efficacy. Analgetic efficacy was manifested in a more marked way; in compound VIII it is comparable with the used standard aminophenazone.

[Comparison of tolerance to hydrophilic contact lenses made of Hema (37% H2O) and Hema-Degma (55%, 65% H2O) in the rabbit eye. I. Changes in corneal transparency due to disturbed hydration]

The authors compared on the rabbit eye the tolerance of hydrophilic contact lenses with equal parameters (0.2 mm central and peripheral thickness, 7.4 radius, 15 mm diameter) with a different degree of hydration (37% H2O-Hema), (55% and 65% H2O-Hema-Degma) during continuous wear for a period of two weeks (1, 2, 3, 4, 7 and 14 days). Special attention was devoted to changes in the transparency of the cornea. Changes of the transparency due to wearing of contact lenses were due to changes of corneal hydration. The cause of increased corneal hydration were metabolic and later also morphological disorders in the corneal endothelium. The activity of Na+-K+-dependent adenosine triphosphatase and gamma-glutamyl transferase were reduced, followed by a change in the shape and size of endothelial cells. Later the activities of both enzymes were reduced also in the epithelium. Keratocytes had reduced alkaline phosphatase and gamma-glutamyl transferase activities. The staining properties of glycosaminoglycans in the stroma remained, however, unaltered, similarly as the activity of acid glycosidases and other investigated lysosomal enzymes. The onset of increased corneal hydration caused by a disorder of the active water ion transport and of metabolites in the cornea depended on the percentage of water in hydrophilic contact lenses. It was observed latest after application of contact lenses with 65% water.

[Aniseikonia and unilateral aphakia]

The author submits the results of correction of unilateral aphakia which is a special type of anisometropia. For more than 500 examined patients with unilateral aphakia all those who had a refraction of the aphakic eye between 9.0 and 15.0 dpt were subjected to statistical analysis. The groups were classified with regard to the refraction of the aphakic eye. From the analysis ensues that optimal results of binocular vision are in the region round 12.0 and 13.0 dpt which is consistent with clinical results.

[Anisomyopia]

During the application of contact lenses the author encountered anisometropia which she corrected in an attempt to reduce aniseikonia by hydrophilic contact lenses produced either in Ergon Prague or in Okula Nýrsko. She examined a total of more than 1,000 patients with anisometropia of more than 2 dpt. As an example she quotes several patients with different refraction who had the less ametropic eye fully corrected, while the other eye was corrected only partly. In complete correction with contact lenses in some instances the aniseikonia increased, while in case of complete correction by spectacle lenses it was not only well tolerated binocularily, but also a certain degree of binocular vision was achieved.

Disturbances in the rabbit cornea after short-term and long-term wear of hydrogel contact lenses. Usefulness of histochemical methods

The influence of soft contact lenses (SCL) with low (37%, L) and high (65%, H) water content on rabbit corneas was investigated. The lenses were worn continuously for 1, 2, 4, 7, 10, 14, 21 or 28 days. The changes in corneal transparency, hydration and enzyme activities were studied. A slight change in corneal transparency due to higher hydration caused by a decreased activity of Na+-K+-dependent adenosine triphosphatase (Na+-K+-ATPase) in the corneal endothelium is followed by a decrease in the activity of gamma-glutamyl transferase (GGT). Slight morphological disturbances appear within 4 days in animals wearing SCL (L). SCL (H) produce similar changes one week later. Subsequently, the corneal epithelium becomes thinner and changes in the size of corneal endothelial cells are obvious. Disturbances of enzyme activities in cells of all corneal layers are present. In the epithelium highly increased activities of acid glycosidases, acid phosphatase, and dipeptidyl peptidase I and II, in keratocytes decreased activities of alkaline phosphatase and GGT, and in the endothelium decreased activity of Na+-K+-ATPase and GGT were found. These changes are more severe after SCL (L). In this case, inflammatory cells displaying high activities of lysosomal hydrolases appear in the anterior part of the stroma during the 3rd and 4th weeks and local degradation of glycosaminoglycans and proteins takes place. In contrast, after SCL (H) a remarkable thinning of the corneas was observed during extended wear, accompanied by decreased stainability of stromal glycosaminoglycans and highly decreased enzyme activities in keratocytes. The histochemical methods proved very useful in the assessment of lesions caused by a continuous wear of SCL.