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Query: UMLS:C0022568 (keratitis)
 5,133 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We evaluated several therapeutic modifications in an attempt to improve efficacy of topical therapy with tobramycin of experimental Pseudomonas keratitis in guinea pigs. Removal of corneal epithelium enhanced efficacy of topical therapy with 0.3 mg/ml and 3 mg/ml tobramycin sulfate but did not influence therapy with 40 mg/ml or 400 mg/ml tobramycin. The highest concentration of antibiotic was the most effective; 7 of 12 infected corneas treated with 400 mg/ml tobramycin were sterile in 48 hours. Therapy begun soon after the infection was established, when there were relatively few organisms present, was more effective than therapy begun later, when there were many more bacteria in the cornea. Our results are consistent with a basic therapeutic concept. The most effective regimen is one that achieves the highest safe concentration of antibiotic at the site of infection as early in the course of infection as possible.
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PMID:Topical tobramycin therapy of experimental Pseudomonas keratitis: an evaluation of some factors that potentially enhance efficacy. 41 2

The effect of prednisolone on tobramycin and carbenicillin therapy for experimentally induced Pseudomonas keratitis was evaluated. Results were assessed quantitatively by determining the number of bacteria that survived in the cornea. Simultaneous administration of prednisolone did not adversely alter results of treatment with carbenicillin or tobramycin. In another trial, pretreatment with prednisolone for 48 hours before antibiotic therapy was begun did not change significantly the results of therapy with intramuscular tobramycin or carbenicillin. We conclude that corticosteroid therapy does not affect adversely results of antibiotic therapy with tobramycin or carbenicillin in this experimental model.
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PMID:Corticosteroid in experimentally induced Pseudomonas keratitis: failure of prednisolone to impair the efficacy of tobramycin and carbenicillin therapy. 41 3

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

The effectiveness of cryotherapy alone and in combination with topical tobramycin sulfate therapy for experimental Pseudomonas keratitis was determined in guinea pigs and rabbits. Results were evaluated quantitatively by determining numbers of viable bacteria surviving in corneas. A brass probe cooled to--79 degrees C and applied directly to infected corneas for six seconds resulted in an immediate 99.9% reduction in bacteria. One freeze-thaw cycle followed by topical tobramycin therapy was significantly more effective than tobramycin therapy alone in five of six strains tested. None of the corneas treated with tobramycin alone demonstrated no growth, whereas 24 of 42 of these infected corneas showed no growth after the combination treatment. We conclude that cryotherapy alone had a rapid bactericdal effect on experimental Pseudomonas keratitis and that it significantly potentiated topical antibiotic therapy for most strains.
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PMID:Cryotherapy for experimental Pseudomonas keratitis. 42 89

We determined the efficacy of tobramycin administered by topical, intramuscular, and subconjunctival routes in guinea pigs and rabbits with experimental Pseudomonas keratitis. The topical route of administration was consistently more effective than either subconjunctival or intramuscular routes. Subconjunctival injection of antibiotic did not enhance the effectiveness of topical therapy in either guinea pigs or rabbits. Intramuscular tobramycin was more effective than saline in guinea pigs with keratitis but not in rabbits with keratitis.
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PMID:Comparison of therapeutic routes in experimental Pseudomonas keratitis. 44 43

We have previously shown that antibiotic therapy of experimental Pseudomonas keratitis was more effective in early moderate infections than in late severe infections. The purpose of this study was to determine the relative efficacies of various drugs, routes, and vehicles in the treatment of moderately severe infection. As in the late severe infections, the most consistently effective regimen was an aminoglycoside applied topically in solution. No synergistic or additive effect was observed with a combination of aminoglycoside given topically and a penicillin given intramuscularly. Topical therapy with antibiotic in ointment was less effective than topical therapy with antibiotic in solution.
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PMID:Experimental Pseudomonas keratitis in guinea-pigs: therapy of moderately severe infections. 46 16

The susceptibility of newborn and infant mice to eye infection by Pseudomonas aeruginosa was studied in 5-, 10-, 15- to 16-, and 21-day-old mice. In the first of three age-related susceptibility experiments, inoculation of P. aeruginosa under the unopened eyelids of infant (5- and 10-day-old) mice in the absence of prior corneal wounding resulted in acute infection and rapid death of many of the animals. However, endophthalmitis was observed in about 30% of bacteremic animals that survived to age 14 to 15 days. In the second experiment, 15- to 16-day-old mice whose eyes were open received P. aeruginosa topically onto either wounded or unwounded corneas. At least 50% of the mice that received both corneal wounding and the bacteria exhibited keratitis, endophthalmitis, and subsequent phthisis bulbi. None of the infected mice died of bacteremia. In addition, mice infected in the absence of corneal wounding did not exhibit any eye damage. In the third experiment, the wounded-cornea responses of 21-day-old mice to P. aeruginosa were more variable. Thirty seven percent of the mice exhibited an intermediate response of decreased eye size and cataracts which was not observed in 15- to 16-day-old mice, 32% recovered spontaneously, and 29% exhibited complete shrinkage of the infected eyes. The variability of the latter responses may reflect a transitional maturation period of natural immunity to the organism in some of the animals, since all 4- to 6-week-old adult mice respond routinely to ocular wounding and similar infections with the organism by undergoing a spontaneous resolvable keratitis (3 to 4 weeks).
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PMID:Age-related susceptibility to Pseudomonas aeruginosa ocular infections in mice. 66 95

An improved method for experimental keratitis due to Pseudomonas aeruginosa is described. Essential features of the method are use of inbred guinea pigs, intracorneal injection of bacteria, subconjunctival injection of antibiotics, "blind" evaluation of results, and statistical analysis of data. Untreated ocular infections were most severe 5 to 7 days after infection. Sterilized bacterial suspensions caused no abnormalities on day 5. Tobramycin and polymyxin B were more active than gentamicin against two strains of Pseudomonas. This model is suitable for many types of quantitative studies on experimental keratitis.
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PMID:Experimental keratitis due to Pseudomonas aeruginosa: model for evaluation of antimicrobial drugs. 81 84

When the ocular toxicity and the in vivo and in vitro effects of gentamicin, Nebcin, and saline solution were compared in experimentally induced Pseudomonas keratitis in rabbits, both antibiotics showed the same toxicity for the rabbits' conjunctival tissues. But Nebcin showed better in vitro and in vivo results than gentamicin, and the clinical effect was confirmed by culture study: significant numbers of organisms were recovered from the corneas of the gentamicin-treated rabbits but none from the corneas of the Nebcin-treated rabbits.
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PMID:Nebcin in the treatment of experimental Pseudomonas keratitis. 81 18

The role of mucin in the manifestation of Pseudomonas keratitis was studied. Pseudomonas was cultivated in solutions of mucin, in which it grew rapidly and then inoculated into rabbit cornea by needle pricks. When the organism was inoculated as a suspension in saline, infection infrequently occurred as small ring abscesses of short duration around a few sites of inoculation. When the organism was inoculated as a suspension in a solution of gastric mucin, infection was usually observed as severe hypopyon-keratitis with formation of a huge ring abscess. Corneal perforation and panophthalmitis resulted in some cases. It was thus concluded that the pathogenicity of Pseudomonas is definitely increased when it was inoculated into the cornea with mucin solution.
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PMID:The role of mucin on experimental Pseudomonas keratitis in rabbits. 81 95


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