Biomedical subjects

E C Alfonso

Publications and source records attributed to E C Alfonso.

24 records · Page 2Linked to original sources

PubMed1993

Microbial keratitis in childhood.

BACKGROUND: Microbial keratitis occurs infrequently in childhood. The leading ocular predisposing factors are trauma and preexisting corneal disease. Many of the age-related risk factors in adults play a minor role in children. METHODS: The authors retrospectively studied 51 eyes with ulcerative keratitis in 50 children younger than 16 years of age. This includes all patients treated at Bascom Palmer Eye Institute during an 11 1/2-year period from January 1, 1980, to June 30, 1991. The criterion for inclusion in the study was a discharge diagnosis of microbial (nonviral) keratitis. RESULTS: The principal risk factors identified in this study were trauma (44%), prior corneal surgery (24%), systemic illness (14%), and contact lens wear (12%). Systemic illness or an immunocompromised state existed in 7 (47%) of the 15 children younger than 3 years of age. There was a large male preponderance (68%). Forty-four (86.3%) of the 51 eyes were culture-positive; six (11.7%) were polymicrobial. Five of seven culture-negative patients had received prior topical antibiotic therapy. Pseudomonas aeruginosa (34%), Staphylococcus aureus (20%), and fungi (18%) were the most common organisms isolated. Seven (14%) eyes required surgery. CONCLUSION: This study presents important differentiating factors between adult and childhood nonviral microbial keratitis. Identification of principal risk factors in children may aid in early recognition and treatment of microbial keratitis.

Adolescent↗

PubMed1993

Defects in an injection-molded intraocular lens.

Injection-molded intraocular lenses may undergo structural changes when exposed to solvents and fixatives during post-mortem examination. We report a case in which this phenomenon was seen in an injection-molded lens. We were able to duplicate these changes by immersing injection-molded lenses in 60% alcohol for 48 hours.

Aged↗

PubMed1992

Rapid detection of gram-negative endotoxin contamination of contact lens saline solutions.

The use of the limulus amoebocyte lysate for the early and rapid detection of gram-negative endotoxin contamination of contact lenses and their solutions could reduce the risk of a keratitis developing that is associated with these devices. Using multiple aliquots from 17 unopened brands of commercially available contact lens saline solutions (15 for soft, two for hard), plus multiple aliquots from these solutions mixed with bacterial endotoxin, we evaluated the ability of two limulus amoebocyte lysate (0.125 endotoxin units/mL) products to detect the presence or absence of gram-negative endotoxin contamination. Sensitivity ranged from 65% (11/17) to 82% (14/17) when the solutions were tested undiluted. When diluted 1:8, the sensitivity increased to 100%. Specificity was 100% for undiluted and diluted specimens. The solutions used for hard contact lenses had the highest false-negative results. The limulus amoebocyte lysate can be used to detect the presence of gram-negative endotoxin in contact lens solutions.

Antimicrobial Cationic Peptides↗

PubMed1990

In vitro toxicity of gentamicin to corneal epithelial cells.

We report morphologic and viability changes in the rabbit corneal epithelium exposed in vitro to gentamicin sulfate. Rabbit corneal epithelial cells (3 x 10(5)) were seeded in replicate 24-well plates at their first in vitro passage, and gentamicin in concentrations of 0, 50, 250, 500, 1,000, or 5,000 micrograms/ml was added to the tissue culture medium beginning 7 days after subculture. By phase contrast microscopy, changes in cell morphologic appearance, particularly increased cytoplasmic granularity, were observed in the 5,000-micrograms/ml groups as early as 24 h after introduction of the drug. At 48 h, similar findings were observed in the 250-micrograms/ml group and at all higher concentrations. The cytoplasmic granularity was not noted in the 0- or 50-micrograms/ml groups. By electron microscopy, these observations correlated with ultrastructural findings of increased accumulations of intralysosomal bodies beginning in the 250-micrograms/ml group after 48 h of exposure to gentamicin. Furthermore, a statistically significant difference (p = 0.001) was demonstrated between the total number of viable cells in the low-dose group (50-micrograms/ml) and the high-dose groups (greater than or equal to 250-micrograms/ml) for exposure periods of 48 h or more. These findings demonstrate aminoglycoside toxicity to corneal epithelial cells in vitro similar to that seen in the human kidney and conjunctiva.

Animals↗

PubMed1988

Necrotizing keratitis caused by Capnocytophaga ochracea.

We studied three cases of Capnocytophaga keratitis that demonstrated stromal necrosis and a ring infiltrate. In all cases, the keratitis occurred in a previously diseased or traumatized cornea. One patient was treated with chronic antiamoebic therapy for presumed Acanthamoeba keratitis. Two cases resulted in corneal perforation. Laboratory isolation was difficult because of slow, fastidious growth. Capnocytophaga is not uniformly sensitive to commonly used topical antibiotics such as the cephalosporins and aminoglycosides, but may respond to treatment with topical clindamycin.

Adult↗

PubMed1987

Amelioration of experimental lipid keratopathy by photochemically induced thrombosis of feeder vessels.

The photochemical interaction between intravenously injected rose bengal dye and 514.5-nm argon laser irradiation was employed to initiate permanent thrombotic occlusions in the corneal neovasculature of rabbit eyes with experimentally induced lipid keratopathy. This photothrombotic procedure did not produce corneal edema or polymorphonuclear leukocyte infiltration, as was found in previous studies employing laser-induced photocoagulation. Thus, by means of the new technique, we avoided the formation of additional neovascularization and lipid deposition. Vascular occlusion by photothrombosis, effected with 8.5 times less incident intensity and 27.5 times less total light exposure than with photocoagulation, yielded an average reduction of corneal cholesterol content of 36% as opposed to an increase of 24% found with previous argon laser photocoagulation.

Animals↗