[Corneal transplantation in Hungary. Data of the National Keratoplasty Registry 1992-1996]

Upon the request of the National Transplantation Committee a nationwide keratoplasty register is functioning at the Department of Ophtalmology, University Medical School of Debrecen. Since then at the end of each year we collected data from the University Departments and Hospitals performing corneal transplantation concerning their keratoplasties and related activities. According to the acquired data the number of corneal transplantations performed in Hungary was 299 in 1992, 298 in 1993, 320 in 1994, 426 in 1995, and 479 in 1996. Keratoplasties in Hungary were performed in 6 University Departments and in 13 Hospitals, all together in 19 institutions in the past five years. The overwhelming majority of corneal transplantations (in 1995 95.8% and in 1996 96.4%) were penetrating keratoplasties. The ratios of lamellar keratoplasties in 1995 and in 1996 were 3.0% and 2.5%, respectively. The ratios of sclerokeratoplasties were slightly above 1% in both years. The distributions of implanted fresh and preserved (eye bank) corneas were around 50-50% in these two years so, that in 1995 a somewhat more and in 1996 somewhat less preserved corneas were used. This ratio for preserved corneas was less than 20% in the period between 1992 and 1994. The law regulating the procurement and the transplantation of corneas is based on presumed consent and explicit objection which is the better type of regulation for the performance of keratoplasties in large numbers. The number of corneal transplantations in Hungary in the past years was close to the figures of industrial countries (England, Germany) calculated for similar populations, inspite of the fact that financing was in many respects unacceptable.

In ophthalmology new possibilities for the use Nd:YAG laser

Results of the technical development in laser technology created new possibilities in ophthalmic surgery, too. The easy access to various lasers offers an extraordinary opportunity for eye surgeons. At the Department of Ophthalmology of the University Medical School of Debrecen we performed 1400 laser treatments in 1996. Out of that 1100 were retinal Argon laser coagulations because of diabetic retinopathy, 200 YAG laser capsulotomies because of secondary cataract, and 30 laser iridotomies because of glaucoma. Additional 70 laser treatments were performed for special indications. During the laser treatment of the retina and the choroid we use Argon gas lasers, whereas the Nd:YAG laser used in the anterior segment of the eye is a solid-state laser. Our pulse mode modus synchronized Nd:YAG apparatus can produce megawatts of energy in nanoseconds. Authors give an account of the Nd:YAG lasers' possibilities in therapy (capsulotomy, iridotomy), present the most frequent indications of treatments in 1996, and compare it with international literature data. Authors demonstrate the newest principles of the Nd:YAG laser treatment of secondary membranes that are occasionally formed in the anterior chamber especially in the area of the pupil following cataract surgery.

Tear plasminogen activators--indicators of epithelial cell destruction. The effect of scraping, n-heptanol debridement, and alkali burn of the cornea on the plasminogen activator activity of rabbit tears

Plasminogen activator (uPA) activities were determined in the tears of rabbits following mechanical (scraping) or chemical (n-heptanol) debridement and alkali burn of the central part of the corneal epithelium. All three types of injury enhanced the plasminogen activator activities in the tears. The increase in uPA activity was highest in alkali burn, lowest for n-heptanol debridement. Scraping yielded an intermediate increase in uPA activity. The maximum value in activator activity was reached at 5 hours for mechanical injury and at 24 hours for chemical injuries. uPA activity values returned to the normal range by the time of re-epithelialization for mechanical scraping and 1-3 days following re-epithelialization for heptanol debridement and alkali burn. A trend was observed between uPA activity level and the size of the wound but the correlation was not pronounced (R = 0.538).

Plasminogen activator inhibitors in human tears

Plasminogen activator inhibitor activity was demonstrated in tears of patients suffering from various corneal and conjunctival diseases. Active plasminogen activator inhibitor was also detected by reverse fibrin zymography in tears of a patient suffering from Sjögren's syndrome and in those who underwent eye surgery. Immunoblotting revealed that both type 1 and type 2 plasminogen activator inhibitors may be present in human tears when the epithelial cells of the cornea and conjunctiva are affected and/or the permeability of the conjunctival blood vessels is increased. The molecular weight of inhibitors suggested the simultaneous presence of both free and activator-complexed inhibitors. However, no plasminogen activator inhibitor was detectable in normal human tears, suggesting that the presence of plasminogen activator inhibitors in tears may be associated with the pathological events at the ocular surface.

Determination of plasminogen activator activities in normal and pathological human tears. The significance of tear plasminogen activators in the inflammatory and traumatic lesions of the cornea and the conjunctiva

Plasminogen activator activity in normal human tears was found to be 0.03 +/- 0.02 IU/ml with casein plate, and 0.06 +/- 0.04 IU/ml with a spectrophotometric method. Elevated levels of plasminogen activator activity (range 0.11-2.05 IU/ml) were detected in the tear fluid of patients suffering from various corneal and conjunctival diseases including corneal ulcers, superficial keratitis, persistent epithelial defects, recurrent erosions, bullous keratopathy, contact lens associated erosions, alkali burns of the cornea, Mooren's ulcer, conjunctival pemphigoid, acute keratoconus, and corneal melanoma. Plasminogen activator activity, determined in the absence of fibrin in tear samples collected by capillary tubes at low flow rates, is considered to be the result of the presence of urokinase-type plasminogen activator (uPA) deriving from the epithelial cells of the cornea and the conjunctiva. It is suggested that an increase in the level of uPA in tears plays an important role not only in ulceration (the formation and repair of epithelial and stromal defects), but also in the development and healing of a number of other inflammatory processes, infections, immunological processes, chemical burns, contact lens associated lesions; in the invasion of microorganisms and leukocytes, in edema formation, in neovascularization, and in the invasive growth of tumors in the cornea and the conjunctiva.

Urokinase-type plasminogen activator in rabbit tears. Comparison with human tears

Plasminogen activator activity was determined in stimulated normal rabbit tears, and was identified as being due to urokinase using specific antibodies. The activator activity is about 100-fold higher in rabbit tears than in human tears. The molecular weight of the activator was determined by fibrin zymography to be 40-50 kDa. However, a multiband pattern of urokinase-type antigen ranging in molecular weight from 60-70 kDa to 200 kDa was detected by immunoblotting. The 60-70 kDa protein was resistant to reduction. The antigen concentration is more than 100-fold higher than the concentration expected from the activity measurement, indicating that most of the urokinase in rabbit tears is in inactive form, such as in inhibitor or receptor complexes.

Hemodynamic changes after ruthenium irradiation of Hippel's angiomatosis

The authors report a case of Hippel's angiomatosis successfully treated with contact beta irradiation. The area of the multiplex retinal angioma and the accompanying retinal detachment was irradiated with a 106Ru/106Rh radioactive applicator. Hemodynamic changes due to irradiation were followed up in the ipsilateral ophthalmic artery with transcranial Doppler sonography. Scarring was also demonstrated by fluorescein angiography and A- and B-scan ultrasonography. Irradiation caused the narrowing and later the occlusion of the precapillaries and capillaries (i.e. the resistance vessels) and that of the shunts inside the angioma; consequently, vascular resistance increased. Transcranial Doppler sonographic recordings showed a decrease in blood flow velocity as compared to pathologically increased blood flow velocity in angiomas, and a gradual increase in vascular resistance which was lower before treatment.

Plasminogen activator activity and plasminogen independent amidolytic activity in tear fluid from healthy persons and patients with anterior segment inflammation

Plasminogen activator activity and plasminogen independent amidolytic activity were measured in human tears by a spectrophotometric method using human plasminogen and chromogenic peptide substrate S-2251. This assay is sensitive predominantly to urokinase-like plasminogen activator. Tears were collected with glass capillaries. The activator activity in normal tears was found to be low, 0.06 +/- 0.04 (SD) IU/ml. Elevated levels were measured in the tears of patients with various types of conjunctival and corneal disorders. The affected epithelial cells of the cornea and conjunctiva were suggested to be responsible for the elevated activity. Plasminogen independent amidolytic activity was usually very low except in cases of increased permeability of the conjunctival blood vessels. The procedure is recommended as a useful tool for the study of the pathological changes in the epithelial cells of the cornea and conjunctiva.

Skeleton of the Oldest Known Pinniped, Enaliarctos mealsi

A nearly complete skeleton of the archaic pinniped Enaliarctos, found in late Oligocene or early Miocene rocks (approximately 23 million years old) of California, provides new evidence on the origin of pinnipeds. Enaliarctos retains many primitive features expected in the hypothesized common ancestor of pinnipeds. Skeletal modifications seen in Enaliarctos document swimming adaptations and indicate that pinnipeds primitively used the axial skeleton and both fore and hindflippers as sources of propulsion. Elongate hindlimbs with prominent bony processes (reflecting powerful musculature) suggest that Enaliarctos was more active on land than modern pinnipeds.

[Sjögren syndrome in childhood]

The authors report on the case of a 7-year-old girl with keratoconjunctivitis sicca. The diagnostic difficulties are discussed and the literary data on Sjögren's syndrome in childhood are summarized.

[Proteolytic enzyme activity and surgical interventions in Mooren ulcer]

The authors report on two cases of Mooren's ulcer. Tear immunoglobulin levels and proteolytic enzyme activity were determined in the different stages of the disease. The latter proved to be more reliable in the assessment of the progress and prognosis of Mooren's ulcer.

A polyacrylamide-gel electrophoretic study of human tear proteins

The protein composition of normal and pathological tears was studied by polyacrylamide-gel (disc) electrophoresis. Polyacrylamide-gel electrophoresis was shown to detect at least 14 fractions in 2-10 microliters of native tears. A comparison was made between the protein composition of normal tears and serum. The most characteristic bands in the tear-protein pattern were identified by parallel electrophoresis of tears, serum, human milk and purified egg-white lysozyme. The identified fractions were specific tear prealbumin, serum albumin, transferrin, lactoferrin and lysozyme. An unidentified major tear-protein component was also described. The tear-protein pattern was divided into six zones: (1) prealbumin zone; (2) post-albumin zone; (3) post-transferrin zone; (4) macroglobulin zone; (5) basic globulin zone; (6) prelactoferrin zone. A significant rise in the level of serum albumin and transferrin was demonstrated in tears from cases of acute catarrhal conjunctivitis. The optimal circumstances were discussed under which major and minor tear components and basic and acidic tear proteins can be determined simultaneously. Polyacrylamide-gel electrophoresis is recommended as a useful method to study the various diseases of the anterior segment of the eye.