Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0022568 (keratitis)
 5,133 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Eighteen patients with typical Herpes simplex virus dendritic keratitis confirmed by viral isolation were treated with corneal collagen shields presoaked with trifluorothymidine for 15 minutes and trifluorothymidine eye drops 5 times daily. The average healing time was 2.9 days (range 1-7 days). No allergic reactions were observed. Toxic punctate keratitis occurred in 3 eyes. The results of this open study suggest that the effect of collagen corneal shields in conjunction with trifluorothymidine shortens the average epithelial healing time compared with other studies that have used antiviral drugs alone.
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PMID:Use of collagen shields in the treatment of herpetic keratitis. 165 Jun 66

Electron microscopic observations, as well as in vitro experiments, on experimental Fusarium solani keratitis of rabbits were performed to study the mode of fungal invasion into the corneal stroma, the interactions between F. solani and inflammatory cells under the influence of topical dexamethasone (DXM) treatment, and the survival mechanism of the fungi in the DXM-treated cornea. Electron microscopy showed that, while the fungus invaded into the corneal stroma, digestion of collagen fibrils occurred around the hyphae, where amorphous material was often noted. In DXM-nontreated cornea, the fungal hyphae were entrapped by pseudopodia of the neutrophils and destruction of the hyphae was noted on day 3 of infection, most hyphae having disappeared by day 7. In the DXM-treated cornea, however, neutrophils could not ingest and destroy the hyphae. In qualitative nitroblue tetrazolium (NBT)-reduction tests using rabbit peripheral blood neutrophils, DXM significantly suppressed the rate of NBT-reduction and the rate of adherence to the fungal microconidia. In the DXM-treated corneal lesions, a considerable increase in both number and size of fungal peroxisomes was noted. Furthermore, the hyphae, surrounded by neutrophils, showed double or triple cell wall formation or sometimes a hypha-in-hypha structure. Similar hypha-in-hypha structures were also observed when the organisms were treated in vitro with a fungistatic concentration of H2O2. We suggest that this special structure is a protective device produced for the survival of F. solani when subject to neutrophil attack in the DXM-treated cornea.
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PMID:Invasion and survival of Fusarium solani in the dexamethasone-treated cornea of rabbits. 166 72

The pathogenesis of peripheral corneal lesions of immune aetiology, like Mooren's ulcer and catarrhal infiltrates, has been related to the formation or deposition of immune compkexes. The present investigation was undertaken to study the mechanisms involved in the elimination of immune precipitates from the cornea. Immune precipitates were induced by injecting human serum albumin (HSA) and rabbit anti-HSA serum into opposite sites of the rat corneal stroma. This resulted in a line-shaped opacity in the stroma, which remained visible by slit-lamp for 7 days, and disappeared without clinical signs of keratitis and uveitis. At the ultrastructural level, the immune precipitates were clearly visible. Keratocytes in the vicinity of the immune precipitates appeared activated, as suggested by their less flattened appearance and well-developed rough endoplasmic reticulum. The arrangement of the collagen fibrils was not affected. Cells with a macrophage-like morphology were also present and contained electron-dense material, closely resembling the precipitate, suggesting phagocytosis. Separate corneas were injected with latex beads, which is known to induce migration of Langerhans cells into the cornea. Immunohistochemical analysis revealed that both latex beads and immune precipitates induced migration of macrophages (ED1+) into the rat corneal stroma. However, differences were observed with regard to the expression of MHC class II antigens by these ED1+ cells and the presence of complement deposits in the corneal stroma. ED1+ cells in corneas injected with latex beads were all MHC class II positive (OX4+), whereas most of the ED1+ cells at the site of the immune precipitates were negative (OX4-).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Elimination of immune precipitates from the rat corneal stroma: a histological study. 193 83

An intrastromal injection of endotoxin lipopolysaccharide (LPS) in one eye of New Zealand albino rabbits induced a prominent keratitis characterized clinically and microscopically by edema and infiltration. Polymorphonuclear leukocytes (PMNs) constituted the primary invading leukocytic element. Collagen synthesis was measured by pulsing the corneas with 3H-proline before inducing inflammation. The invasion of the cornea by leukocytes did not alter the conversion of proline to hydroxyproline significantly in the stroma during the 14-day observation period, signifying that there were only negligible changes in the rate of collagen synthesis. However, the percentage of total stromal protein represented by collagen (ie, collagen/total protein) was only 50% of that in comparable corneas receiving an injection of phosphate-buffered saline. Some animals were rendered leukopenic by intravenous nitrogen mustard before intrastromal LPS injection caused a less severe corneal inflammatory response, characterized microscopically by fewer infiltrating leukocytes. Similarly, in nonleukopenic rabbits, topical therapy with 1% prednisolone acetate markedly reduced the corneal inflammatory response which also was characterized by fewer invading leukocytes. In neither instance was there extreme collagen loss, suggesting that the loss of stromal collagen is related to PMN infiltration.
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PMID:Quantification of stromal destruction in the inflamed cornea. 200 34

External devices have been used to enhance drug delivery. This article reviews the role of collagen shields, iontophoresis, and pumps used to deliver ophthalmic medications. Collagen shields have been used to deliver drugs and promote corneal epithelial healing. Presoaked collagen shields deliver many drugs to the eye as well as or better than traditional methods such as frequent topical therapy or subconjunctival injection. The efficacy of drug delivery by collagen shields was demonstrated in animal models of graft rejection and bacterial keratitis. Iontophoresis uses an electrical current to carry an ionized drug across tissue. Transcorneal iontophoresis delivers high concentrations of a drug to the anterior segment of the eye. Transscleral iontophoresis bypasses the lens-iris diaphragm and produces adequate vitreous levels. Pumps deliver fluid to the eye for extended periods of time via a tube with its distal opening in the conjunctival sac, corneal stroma, anterior chamber, or vitreous cavity. Clinical acceptance of the collagen shield for drug delivery to the anterior segment is better than iontophoresis or pumps, probably because the collagen shield is simpler and more convenient to use.
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PMID:Device drug delivery to the eye. Collagen shields, iontophoresis, and pumps. 206 8

The Pseudomonas aeruginosa slime-glycolipoprotein (GLP) is considered as one of the principal pathogenetical factors of the bacterium. A single dose of 100 micrograms of the P. aeruginosa slime-GLP was injected in rabbit corneas intrastromally. Light microscopy showed that 4 hours after the injection, polymorphonuclear leucocytes (PMNs) began to infiltrate the anterior stroma. 24 hours after the intrastromal injection, PMNs had infiltrated full corneal thickness followed by multiple absceses formation, loss of epithelial and endothelial cells, disorganisation of normal collagen fibres and hyperplasy of fibroblasts. These morphological observations are very similar to those observed during experimental P. aeruginosa keratitis and show that the P. aeruginosa slime-GLP is at least in part responsible for the characteristic liquefaction necrosis of the keratitis induced by the P. aeruginosa.
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PMID:[Histologic study of corneal lesions caused by the slime-GLP glycolipoprotein of Pseudomonas aeruginosa]. 212 33

Axenic cultures of Acanthamoeba castellanii contained a collagenolytic enzyme that digested collagen shields and purified collagen in vitro. Specificity of biologic activity was determined by the addition of selected enzyme inhibitors to the assays and revealed that the parasite-conditioned medium contained both collagenase and lower concentrations of other proteolytic enzymes. However, most of the collagenolytic and pathogenic activity was directly attributable to specific collagenase. Intrastromal injection of sterile, Acanthamoeba-conditioned culture medium into naive Lewis rats produced corneal lesions clinically similar to and closely resembling those found in biopsy specimens of human patients diagnosed with acanthamoebic keratitis. Histopathologic analysis revealed moderate-to-severe neutrophil infiltration, disruption of stromal lamellae, and edema. Identical pathologic sequelae were produced by intrastromal injection of purified collagenase (25 units/ml). The pathogenicity of the soluble parasite-derived product was removed by passage over affinity columns armed with antibody specific for collagenase. These results indicated that soluble parasite-derived factors were capable of producing lesions characteristic of acanthamoebic keratitis and that the pathogenicity of these factors was either directly or indirectly attributable to specific collagenase activity.
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PMID:In vivo and in vitro collagenolytic activity of Acanthamoeba castellanii. 217 83

To get a better understanding of the possible role of proteases in the pathogenesis of fungal keratitis, the extracellular proteases of a clinical isolate of Aspergillus flavus, from a severe case of keratitis, were identified and partially characterized. This strain, designated CU226/88, was grown with a variety of substrates as nitrogen sources, under conditions that would be expected to derepress the production of extracellular proteases. When grown on minimal medium with milk protein as a nitrogen source, the fungus appeared to produce primarily a metalloprotease, which has a zinc cofactor. When grown with insoluble collagen or elastin as a nitrogen source, a serine protease and cysteine protease, as well as the metalloprotease, are produced. Strain CU226/88 can grow with collagen, but not elastin, as the sole source of carbon as well as nitrogen. It is possible that the collagenase activity is a mediator of the severe corneal destruction caused by this isolate.
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PMID:Extracellular proteases of Aspergillus flavus. Fungal keratitis, proteases, and pathogenesis. 217 95

The effects on corneal wound healing of two topical nonsteroidal anti-inflammatory agents, flurbiprofen sodium (0.03%) and diclofenac sodium (0.1%), and the topical corticosteroid, prednisolone sodium phosphate (1%), were evaluated in masked, controlled rabbit studies. Healing of epithelial scrape wounds was significantly retarded in all three treatment groups for the first 3 days after wounding. There was no difference in the epithelial healing rate between the two nonsteroidal or corticosteroid treatment groups. Clinical grading of epithelial quality, conjunctival hyperemia, keratitis, stromal edema, and corneal haze were similar in all groups. There was a significant early decrease in the iritis score in the diclofenac treatment group. The strength of 2-mm central penetrating corneal trephination wounds and the collagen content of these wounds were similar in all groups. Both the topical nonsteroidal anti-inflammatory agents and the corticosteroid used in the preparations and dosages investigated in this study decreased early epithelialization of scrape wounds but had no apparent effect on corneal stromal healing. No toxic effects of the various drugs were found.
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PMID:Topical nonsteroidal agents and corneal wound healing. 232 60

Proteolytic enzyme inhibitors are capable of preventing decomposition of the collagen structures of the corneal stroma, and also have a regulating influence on various aspects of the inflammatory process. The content of proteolytic enzymes (alpha 1-antitrypsin and alpha 2-macroglobulin) was studied in the tears and the blood serum of patients with herpes viral keratitis, as well as in the blood serum of rabbits with experimentally-induced ophthalmoherpes. Herpetic keratitis was attended by significant changes in the content of proteolysis inhibitors, as well as in the peripheral blood neutral proteases activity, this presumably serving as a nonspecific blood protective reaction to the inflammation. In the tears of patients suffering from herpetic keratitis the inhibitors are expended for binding activated proteases in the cornea. Local application to rabbits of protein preparations with an inhibitory effect (contrykal, gordox) at the acute period of the experimentally-induced ophthalmoherpes produced a marked antiphlogistic effect.
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PMID:Antiproteases in herpetic keratitis. 245 13


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