J. Obenberger

Aqueous humour and plasma cortisol levels in glaucoma and cataract patients

By means of radioimmunoassay, the content of endogenous cortisol in the aqueous humour and plasma of 35 patients suffering from various types of glaucomas and 35 cataract patients was determined, and the ratio of the plasma to the aqueous humour cortisol levels was calculated. The highest cortisol level in both plasma and aqueous humour was found to occur in patients with open-angle glaucoma suffering at the same time from systemic hypertension. The lowest plasma to aqueous humour cortisol ratio was found in patients with secondary glaucoma treated with steroids. In woman suffering from open-angle glaucoma, the rising cortisol level in plasma with age contrasted to the decreasing cortisol level in aqueous humour. The authors suggest that there is an active interference with homeostatic mechanisms responsible for ensuring the stability of the eye inner milieu and a certain protection of the trabecular meshwork of the angle of the anterior eye chamber against noxious effects of the endogenous cortisol.

Specular microscopy of the corneal endothelium after liquid silicone injection into the vitreous in complicated retinal detachments

Twenty-one patients were followed up for at least 6 months after pars plana vitrectomy and liquid silicone injection into the vitreous for complicated retinal detachment by means of specular microscopy. In 17 eyes without silicone penetration into the anterior chamber, only insignificant changes were observed. In contrast, in 4 eyes, where a large drop of liquid silicone penetrated into the anterior chamber, the cell densities rapidly decreased to critical values and a marked pleomorphism of large endothelial cells with abnormal intracellular details indicated serious damage of the surviving cells. A characteristic structureless reflecting layer with contourlike lines in some areas of the specular image was a newly observed bizarre change that was caused by the replacement of the anterior chamber fluid by liquid silicone with markedly different optical properties.

Paper Strips and Rings as Simple Tools for Standardization of Experimental Eye Injuries

Description of a new simple method using Whatman No. 1 chromatographic paper strips and rings for production of standardized corneal burns. Details of the method as well as multiple usage for various

Steroids and intraocular pressure

Abstract The intraocular pressure is dependent upon the aqueous humour formation by the ciliary body and on the outflow through the trabecular meshwork localized in the anterior chamber angle of the eye. In the ciliary body epithelium the active sodium transport has been demonstrated and effects of mineralocorticoids has been suggested but not yet equivocally confirmed. Outflow facility of the trabecular meshwork is connected with the presence of acid mucopolysaccharides. Clinical overdosage of glucocorticoids results in an increase of intraocular pressure, so-called steroid glaucoma. It is explained by the action of glucocorticoids on the stabilization of lysosomal enzymes needed for physiological decomposition of these macromolecular substances. Disbalance of oestrogen supply may lead to disorder in intraocular pressure, too. The occurrence of glucocorticoids, mineralocorticoids, oestrogens and testosterone of endogenous origin in aqueous humour, the metabolism of these hormones and evidence for formation of steroid-receptor complexes is presented.

Changes of activity of alkaline and acid phosphatase in the rabbit eye in the early phase of alkaline and acid injury.

Rabbit corneas were burned either with 1.0 N sodium hydroxide or 1.0 N hydrochloric acid. Enzyme activities of alkaline and acid phosphatases were examined spectrophotometrically in the homogenates of cornea, iris, aqueous humor and vitreous body. On the 3rd day after alkaline as well as acid burn, a significant decrease of both enzyme activities was produced as compared with untreated animals. A more pronounced change was found in the case of alkaline injuries. With both kinds of caustic agents the decrease of acid phosphatase activity was more striking than that of the alkaline phosphatase. Advantages and shortcomings of biochemical and histochemical enzymatic determinations in experimental ocular inflammations are briefly discussed. Die Cornea von Kaninchenaugen wurden entweder mit 1N Natriumhydroxyd oder mit 1N Salzsäure geätzt. Spektrografische Bestimmung der Fermentaktivität der alkalischen und sauren Phosphatasen in Hornhaut, Regenbogenhaut, Kammerwasser und Glaskörper. 3 Tage nach der durch Natriumhydroxyd oder Salzsäure hervorgerufenen Schädigung zeigte sich signifikante Aktivitätsabnahme beider Fermente. Stärkere Veränderungen wurden nach Alkalischädigung gefunden. Beide kaustische Einwirkungen verursachten eine deutlichere Aktivitätsabnahme der saueren als der alkalischen Phosphatase. Kurze Diskussion der Vorteile biochemischer und histochemischer Methoden für Fermentbestimmungen bei der experimentellen Augenentzündungen.

Ring-shaped alkali burns of the rabbit cornea

Rabbit corneas were burned by touching their surfaces with rings of Whatman No. 1 Chromatographic paper soaked in 1N NaOH. The corneal epithelium and endothelium were studied by impregnating flat sections with McGoverns and Jaboneros silver stains. Immediate destruction as well as regeneration of both cellular layers is described. Ringförmiges chromatographisches Papier Whatman No. 1 wurde mit 1N NaOH imprägniert, Ätzung von Kaninchenhornhäuten durch Kontaktberührung mit dem Papierring. Hornhautepithel und Endothel wurden mit Flachschnittechnik und nachfolgender Silberimprägnation nach McGovern und Jabonero untersucht. Beschreibung der unmittelbaren Ätzschädigung und Regeneration beider Hornhautgrenzschichten.

Alkali Burns of the Rabbit Cornea. Corneal Uptake of 14C-Glucose Injected into the Anterior Chamber

An experimental alkali burn was produced in rabbits dropping 1 N NaOH on the proptosed eye. At intervals of 1 h–9 days after injury, the 14C-glucose was injected into the anterior chamber a

The effect of liquid silicone on the corneal endothelium in rabbits. A comparative specular microscopic and histopathologic study.

Specular microscopic and histopathologic findings in the corneal endothelium were compared after the injection of liquid silicone into the anterior chamber of both eyes in 15 rabbits. The findings demonstrated serious damage to the endothelium in the area of contact of liquid silicone with the posterior surface of the cornea and disclosed some problems in the interpretation of specular microscopic findings. An abnormal endothelial mosaic can be probably found even in a zone of preserved intercellular borders or in a zone with a relief of the bases of extinct endothelial cells.

Quantitative determination of endogenous corticosteroids in the rabbit plasma and aqueous humor.

Competetive protein binding technique represents a new very sensitive, specific and rapid method for determination of minute amounts of endogenous steroids. It was used for determination of corticosteroids in the rabbit primary and secondary aqueous humors, as well as in the plasma. Three different sets of aqueous humor samples were analyzed, namely primary aqueous from the left eye, secondary aqueous from the same eye, and primary aqueous from the right eye, both latter withdrawn after an interval of three hours: values of 7.76±4.33, 4.61±2.22, and 4.37±2 73 ng per ml, respectively, were obtained. Plasmatic values, at corresponding time intervals, were nearly ten-times higher, i. e. 5.6+1.65, and 5.9+0.98 μg per 100 ml, respectively. Parallel flurometric determination of plasmatic levels of corticosterone and cortisol was in good agreement, showing 4–5 times prevalence of the corticosterone over cortisol.

The role of corticosteroids in the homeostasis of the eye

Three problems were studied on the human and rabbit eye: to what extent the mineralocorticoids contribute to the control of Na+ and K+ transport in the lens epithelium, how do the glucocorticoids influence the concentration of glucose in the aqueous humour and what is the effect of the pituitary-adrenal axis on the hemato-ocular barrier. Specific receptor-like proteins binding aldosterone were found in the lens epithelium. Na+ and K+ concentrations in the aqueous were influenced by both aldosterone and spironolactone administration. The aldosterone concentration in human cataracts was found to be higher in cases of cataracts complicated by arterial hypertension. In spite of some indication of anticataractogenous action of mineralocorticoids, aldosterone did not prevent the formation of cortisol-induced cataract in chick embryos. Glucose concentration in the aqueous was increased by glucocorticoid administration as well as by stimulation of their secretion by ACTH. Further, the contribution of the pituitary-adrenal axis to the breakdown of the hemato-ocular barrier was investigated by measuring the changes of the total protein content in the aqueous. ACTH1-24 caused a partial breakdown of the barrier, as well as ACTH4-10 or alpha-MSH. As the latter two peptides lack the stimulative effect on the corticoid secretion and glucocorticoids themselves fail to increase the protein content in the aqueous, the breakdown of the hemato-ocular barrier seems to be essential for ACTH-linked peptide fragments and is not mediated by corticoids.