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)

Extracellular proteases of three cornea-virulent strains of Pseudomonas aeruginosa were isolated by sequential ammonium sulfate precipitation, Ultrogel AcA 54 gel filtration, and flat-bed isoelectric focusing. The purity of the preparations was determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis , thin-layer isoelectric focusing in polyacrylamide gel, immunodiffusion and immunoelectrophoretic procedures, and tests for the presence of other known pseudomonal products. Light and electron microscopic examination of rabbit corneal lesions observed 4 to 6 h after the intracorneal injection of submicrogram amounts of the proteases revealed: (i) degeneration and necrosis of epithelium, endothelium, and keratocytes, (ii) infiltration, degeneration, and necrosis of polymorphonuclear leukocytes, (iii) loss of the characteristic weblike pattern, colloidal iron staining, and ruthenium red staining of the stromal proteoglycan ground substance, (iv) dispersal of strucutrally normal appearing collagen fibrils, ground substance, (iv) dispersal of structurally normal appearing collagen fibrils, and (v) accumulation of plasma proteins and fibrin in the necrotic corneas. These structural alterations are very similar to those observed previously during experimental P. aeruginosa keratitis, and this similarity supports the idea that pseudomonal proteases are responsible, at least in part, for the rapid and extensive liquefaction necrosis characteristic of pseudomonal-induced keratitis. In addition, the results support the idea that pseudomonal proteases elicit severe corneal damage by causing the loss of the corneal proteoglycan ground substance, thus resulting in dispersal of undamaged collagen fibrils, weakening of the corneal stroma, and subsequent descemetocele formation and corneal perforation by the anterior chamber pressure.
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PMID:Purification of Pseudomonas aeruginosa proteases and microscopic characterization of pseudomonal protease-induced rabbit corneal damage. 41 81

Because Acanthamoeba keratitis associated with contact lenses were described, several solutions used in stationary eye wash stations were contaminated by free-living amoebae. 0.9% sodium chloride rinsing solutions allowed cyst and trophozoite growth and only one solution for decontamination using hydrogen peroxide led to rapid elimination of cysts and trophozoites. Antiseptic solutions containing ammonium derivatives or chlorhexidine killed only trophozoites. Because of the constant contamination of tap water with Acanthamoeba cysts resistant to chlorine, the prevention of amoebic keratitis in wearers of contact lenses needs: use of sterile solutions for decontamination or rinsing, choice, if possible, of oxidizing solutions, suppression of tap water for rinsing.
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PMID:[Possibility of the survival of free-living amoebae which cause keratitis in decontamination solutions used for the maintenance of contact lenses]. 279 May 30

Members of the genus Acanthamoeba are increasingly recognized as agents of indolent, chronic, infectious keratitis. Recently, Acanthamoeba corneal infection has been reported in some persons who wear soft contact lenses. In this study, three "heat" and three "cold" soft contact lens disinfection systems were tested according to the manufacturers' instructions against Acanthamoeba castellanii and Acanthamoeba polyphaga in separate trials, and with appropriate controls. Suspensions of Acanthamoeba cysts or trophozoites of each species were tested individually. Each of the three heat disinfection units killed all acanthamoebae in one cycle in all trials. A chlorhexidine 0.005%/thimerosal 0.001% solution killed A. castellanii trophozoites and cysts, but those of A. polyphaga survived. Trophozoites and cysts of both species survived an alkyl triethanol ammonium chloride 0.013%/thimerosal 0.002% solution and a hydrogen peroxide 3% preparation. Heat disinfection overall appears to be more effective in killing Acanthamoeba trophozoites and cysts as compared to cold disinfection methods.
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PMID:Susceptibility of Acanthamoeba to soft contact lens disinfection systems. 395 82

A number of 5-heteroaromatic-substituted 2'-deoxyuridines were synthesized from 5-iodo-2'-deoxyuridine using tetraorganotin reagents and palladium complexes as catalyst. The palladium-catalyzed cross-coupling reaction between 5-iodo-2'-deoxyuridine and stannylated heteroaromatics was optimized for the synthesis of the 5-thien-3-yl-2'-deoxyuridine and 5-furan-3-yl-2'-deoxyuridine. 5-(5-Iodothien-2-yl)-2'-deoxyuridine was used as starting material for the synthesis of 5-(5-methylthien-2-yl)-2'-deoxyuridine, 5-(5-vinylthien-2-yl)-2'-deoxyuridine, and 5-(5-ethynylthien-2-yl)-2'- deoxyuridine. 5-(5-Nitrothien-2-yl)-2'-deoxyuridine was synthesized using ceric ammonium nitrate as reagent. 5-(Isoxazol-5-yl)-2'-deoxyuridine was synthesized from 5-(3-oxopropyn-1-yl)-2'-deoxyuridine. Finally, 5-(5-chlorothien-2-yl)-beta-D-arabinofuranosyluracil and 5-(5-bromothien-2-yl)-beta-D-arabinofuranosyluracil were obtained by halogenation of 5-thien-2-yl-beta-D-arabinofuranosyluracil. Introduction of an alkyl substituent in the 5-position of the thienyl group of 5-thien-2-yl-2'-deoxyuridine or substitution of the 2-deoxyribofuranose ring by an arabinofuranose moiety gave decreased activity against HSV-1 and VZV replication when compared with the 5"-halogenated-5-thien-2-yl-2'-deoxyuridines. 5-(5-Bromothien-2-yl)-2'-deoxyuridine caused prompt healing of HSV-1 keratitis when administered as eye drops (0.2%) to rabbits.
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PMID:Synthesis and antiviral activity of 5-thien-2-yl-2'-deoxyuridine analogues. 838 74

In order to evaluate the possible roles of secretory proteases in the pathogenesis of amoebic keratitis, we purified and characterized a serine protease secreted by Acanthamoeba lugdunensis KA/E2, isolated from a Korean keratitis patient. The ammonium sulfate-precipitated culture supernatant of the isolate was purified by sequential chromatography on CM-Sepharose, Sephacryl S-200, and mono Q-anion exchange column. The purified 33 kDa protease had a pH optimum of 8.5 and a temperature optimum of 55 degrees C. Phenylmethylsulfonylfluoride and 4-(2- Aminoethyl)-benzenesulfonyl-fluoride, both serine protease specific inhibitors, inhibited almost completely the activity of the 33 kDa protease whereas other classes of inhibitors did not affect its activity. The 33 kDa enzyme degraded various extracellular matrix proteins and serum proteins. Our results strongly suggest that the 33 kDa serine protease secreted from this keratopathogenic Acanthamoeba play important roles in the pathogenesis of amoebic keratitis, such as in corneal tissue invasion, immune evasion and nutrient uptake.
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PMID:Purification and characterization of a 33 kDa serine protease from Acanthamoeba lugdunensis KA/E2 isolated from a Korean keratitis patient. 1469 59

A novel antiviral protein was purified from an extract of Grifola frondosa fruiting bodies using a procedure that included 40% ammonium sulfate precipitation and DEAE-cellulose ion exchange chromatography, and designated GFAHP. This protein inhibited herpes simplex virus type 1 (HSV-1) replication in vitro with an IC(50) value of 4.1 microg/ml and a therapeutic index >29.3. Higher concentrations of GFAHP (125 and 500 microg/ml) also significantly reduced the severity of HSV-1 induced blepharitis, neovascularization, and stromal keratitis in a murine model. Topical administration of GFAHP to the mouse cornea resulted in a significant decrease in virus production (mean virus yields: 3.4log10PFU in the treated group and 4.19log10PFU in the control group). We proved that GFAHP directly inactivates HSV-1 while simultaneously inhibiting HSV-1 penetration into Vero cells. Gel electrophoresis showed that GFAHP had a molecular weight of 29.5 kDa. GFAHP was tryptic digested and analyzed from the PMF of matrix assisted desorption ionization-time of flight mass spectrometry (MALDI-TOF-MS) and nanoelectrospray ionization tandem mass spectrometry. The N-terminal sequence of GFAHP consisted of an 11 amino acid peptide, NH(2)-REQDNAPCGLN-COOH that did not match any known amino acid sequences, indicating that GFAHP is likely to be a novel antivirus protein. To our knowledge, this is the first report that characterizes an anti-HSV protein from G. frondosa.
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PMID:Isolation, identification and function of a novel anti-HSV-1 protein from Grifola frondosa. 1747 44

Acanthamoeba spp. are the causative agents of granulomatous amoebic encephalitis (GAE) and amoebic keratitis. Recent studies performed by Rassu et al. showed that, compared with the free drug, the loading of rokitamycin in chitosan microspheres improves and prolongs the in vitro antiamoebic activity of rokitamycin. This could be useful in transporting the drug for either ocular application to treat amoebic keratitis or nasal administration as an alternative route for the administration of the drug to the brain in GAE therapy. Starting from the previous study, our goal was to optimize the technological parameters in order to obtain chitosan microparticles loaded with rokitamycin and to evaluate the use of new quaternary ammonium chitosan derivatives in the preparation of spray dried microspheres containing the macrolide; these derivatives showed better characteristics (solubility, penetration enhancement) compared with chitosan itself. Toxicity studies on new polymers were performed. Spray dried loaded microspheres based on chitosan or chitosan derivatives were obtained by using appropriate preparative parameters. Microparticles containing chitosan derivatives showed similar or often better properties than formulations made of chitosan with respect to size, in vitro release behaviour and mucoadhesiveness thus making them more suitable for ocular or nasal administration. New polymers did not demonstrate cytotoxicity.
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PMID:New chitosan derivatives for the preparation of rokitamycin loaded microspheres designed for ocular or nasal administration. 1947 81

Acanthamoeba species are frequently isolated from soil and water collections. In the environment, the organisms multiply as phagotrophic trophozoites and encyst under adverse conditions. Several species are known to infect man, causing keratitis and opportunistic diseases. The mechanisms underlying tissue damage and invasion by the amoebae are being elucidated and the involvement of secreted peptidases, particularly serine peptidases, has been demonstrated. Here, elastase activity was examined in Acanthamoeba-conditioned medium (ACM), making use of elastin-Congo red (ECR) and synthetic peptide p-nitroanilide substrates. ACM hydrolysed ECR over a broad pH range and optimally at a pH of 7.5 and above. Indicating the activity of serine and metallopeptidases, Congo red release was potently inhibited by PMSF, antipain, chymostatin and 1,10-phenanthroline, partially reduced by elastatinal and EDTA, and unaffected by 1,7-phenanthroline and E-64. Screening with synthetic substrates mainly showed the activity of serine peptidases. ACM efficiently hydrolysed Suc-Ala(2)-Pro-Leu-pNA and Suc-Ala(2)-Pro-Phe-pNA over a broad pH range (7.0-9.5) and was weakly active against Suc-Ala(3)-pNA, a substrate found to be optimally hydrolysed at a pH around 7.0. Following ammonium sulfate precipitation of ACM proteins and FPLC analysis, the majority of the ECR-splitting activity, characterised as serine peptidases, bound to CM-sepharose and co-eluted with part of the Suc-Ala(2)-Pro-Phe-pNA-hydrolysing activity in a gradient of 0-0.6M NaCl. In the corresponding FPLC fractions, serine peptidases resolving in the region of 70-130kDa were detected in gelatin gels. Overall, the results demonstrate that trophozoites secrete elastases, and additionally suggest the high molecular weight serine peptidases as possible elastase candidates.
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PMID:Elastase secretion in Acanthamoeba polyphaga. 1963 88

Autophagy protects cells from intracellular pathogens, but can be exploited by some infectious agents to their benefit. Currently it is not known if bacteria induce autohpagy in cells of the cornea. The goal of this study was to develop an ocular surface autophagy reporter cell line and determine whether ocular bacterial pathogens influence host responses through autophagy induction. The cell line was made using lentivirus transduction of an LC3-GFP fusion protein in human corneal limbal epithelial (HCLE) cells. LC3-GFP puncta in HCLEs were induced by rapamycin and ammonium chloride treatments, and prevented by the autophagy inhibitors 3-methyladenine (3'MA) and bafilomycin. Importantly, secretomes from Escherichia coli, Serratia marcescens, Staphylococcus aureus, methicillin sensitive (MSSA) and resistant (MRSA), were found to induce autophagy, whereas other bacteria, including Acinetobacter baumannii, Achromobacter xylosoxidans, Enterococcus faecalis, Klebsiella pneumoniae, Moraxella sp., and Stenotrophomonas maltophilia, did not. Our data indicates differences between tested ocular isolates of MRSA and MSSA in the activation of autophagy. HCLEs treated with 3'MA were slightly more susceptible to cytotoxic factors produced by S. marcescens and MRSA keratitis isolates, by contrast, bafilomycin A1 treatment caused no difference. This work demonstrates the successful development and validation of an autophagy reporter corneal cell line and indicates differences between ocular bacterial isolates in the activation of autophagy.
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PMID:Bacteria induce autophagy in a human ocular surface cell line. 2928 46

Acanthamoebae are facultative parasites causing rare but serious infections such as keratitis and encephalitis and are also known as vectors for several bacterial pathogens, including legionellae and pseudomonads. Acanthamoeba cysts are particularly resilient and enable the amoebae to withstand desiccation and to resist disinfection and therapy. While the search for new therapeutic options has been intensified in the past years, hand and surface disinfectants as well as topical antiseptics for preventing infections have not been studied in detail to date. The aim of this study was to screen well-known and commonly used antimicrobial products in various formulations and different concentrations for their efficacy against Acanthamoeba trophozoites and cysts, including aliphatic alcohols, quaternary ammonium compounds (QACs), peracetic acid (PAA), potassium peroxymonosulfate sulfate (PPMS) and octenidine dihydrochloride (OCT). Of all products tested, OCT and QACs showed the highest efficacy, totally eradicating both trophozoites and cysts within 1 min. The determined 50% effective concentration (EC50) for cysts was 0.196 mg/mL for OCT and 0.119 mg/mL for QACs after 1 min of exposure. PAA and PPMS showed reliable cysticidal efficacies only with prolonged incubation times of 30 min and 60 min, respectively. Aliphatic alcohols generally had limited efficacy, and only against trophozoites. In conclusion, OCT and QACs are potent actives against Acanthamoeba trophozoites and cysts at concentrations used in commercially available products, within contact times suitable for surface and hand disinfection as well as topical antisepsis.
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PMID:Anti-Acanthamoeba disinfection: hands, surfaces and wounds. 3273 77


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