Biomedical subjects
Publications and source records attributed to V Victoria-Troncoso.
The ultrastructural study of the corneo-scleral trabeculum in steroid induced glaucoma shows a greater endothelial activity and an increase of the ground substance and of the cytoplasmic organelles, as well as a great sensitivity of the ground substance to hyaluronidase. The morphometric study of the cytoplasmic organelles showed a significant difference between treated and non-treated eyes.
The conjunctival biopsy of gyrate atrophy of the choroid and retina displays, besides some atypical changes, the accumulation in the epithelial cells of osmiophilic particles, which are probably lipids and which are also found in the fibroblasts of the conjunctival stroma.
In eyes treated with corticosteroids the thickness of the trabecula is increased, the width of the intertrabecular spaces reduced and the number of trabecula per surface unit greater. In eyes perfused with hyaluronidase the opposite is seen, i.e., the thickness of the trabecular is reduced, the width of the intertrabecular spaces increased and the number of trabecula per surface unit diminished. The number of glycoproteins in the ground substance increases after treatment with corticosteroids while perfusion with hyaluronidase has the opposite effect. We have treated 27 rabbits, of which 17 with local administration of Dexamethasone 0,1%, 5 with subconjunctival injections and 5 as controls.
The lysosomal cycle has been studied in the primary cultures of corneal epithelium infected with type I herpes virus. Immediately after the infection, the lysosomal system develops. There is a great dispersion in the morphometric analysis of the lysosomal particles. They represent a heterogeneous population with regard to their size. The number of lysosomal particles increases very rapidly during the first hours after the herpetic infection. Finally, many cells become round and die.
Following perfusion of the anterior chamber with hyaluronidase, a great reduction in the basic substance of the sclero corneal trabeculum as well as increased activity of the goniocytes were observed with the electron microscope. The opening of the trabecular meshes thus produced constitutes a kind of chemical trabeculectomy, attributable to the depolymerization of the hyaluronates of the basic substance by the hyaluronidase of the goniocytes.
Changes in corneal epithelium in macular dystrophy are secondary. Those in lattice dystrophy are primary, the epithelial cells showing the characteristics of cancer cells as well as hypertrophy of the lysosomal system and vacuolisation with autolysis. After infection by herpes virus the epithelial cells show an increase in number and volume of the lysosomes, which liberate enzymes with cytolytic effects.
The changes of the cornea epithelium in the case of macular dystrophy are secondary. Those in lattice dystrophy are primary, the epithelial cells exhibiting the characteristics of cancer cells as well as hypertrophy of the lysosomal system and vacuolisation with autolysis.
The non-depolymerised mucopolysaccharides of the anterior chamber angle can become hydrated. This biological oedema can obstruct the trabeculae, but the physiological liberation of catabolic enzymes from the lysosomes depolymerises the mucopolysaccharides and prevents this obstruction. This is, on the contrary, facilitated by the corticosteroids, which reinforce the lysosomal membranes and impede the liberation of the catabolic enzymes. There are clones of goniocytes which are corticosensitive and others which are not. Depending upon the predominance of one or the other, the cortisone test will be positive or negative. The outflow facility of the aqueous humour is determined by the hydration state of the trabeculae. This state depends upon the polymerisation of the mucopolysaccharides of the trabecular skeleton.
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The mitochondrias of the hyalocytes contain lactic dehydrogenase but no glucose-6-phosphate dehydrogenase, so that only aerobic respiration is possible. Among the lysosomal enzymes, acid phosphatases and beta-glucuronidase are found, the latter facilitating the turnover of the hyaluronic acid. There is no galactosidase, as the hyaluronic acid of the vitreous does not contain galactose.
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Since we use a very strict control of the viability of the endothelium of the graft, we have no more failures in corneal grafting not even in cases with bad prognoses, such as Fuchs' endothelial dystrophy. On the contrary, in corneal grafting without this control, we had failures in 20% of the cases.
Compared with the normal lens, the cataractous lens is characterized by morphological and distribution anomalies of the epithelial cells. At the electron microscope an enlargement of the intercellular spaces and large intercellular, as well as intracellular, vacuoles are seen. An important development of the lysosomal system and of the endoplasmic reticulum is also observed.
Tissue culture of cataractous lens epithelium shows deterioration of cellular tropism, anisomorphism, anisometry, and formation of large intracytoplasmic vacuoles with deterioration of the lysosomal system, the vacuolated cells showing no tendency to form fibers.
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Since we use a very strict control of the viability of the endothelium of the graft, we have no more failures in corneal grafting, even not in cases with bad prognosis, such as Fuch's endothelial dystrophy. On the contrary, in corneal grafting without this control, we had a failure in 20% of the cases.