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Biomedical subjects

R A Hyndiuk

Publications and source records attributed to R A Hyndiuk.

At least 19 recordsLinked to original sources
PubMed1992

Blastomycosis of the eyelid and conjunctiva.

A 37-year-old man with a recurrent papillomatous lesion of the upper eyelid and four separate bulbar conjunctival ulcers was found to have North American blastomycosis. This represents the first reported case with conjunctival lesions that were not simply contiguous with eyelid involvement. This case underscores the importance of considering blastomycosis in the differential diagnosis of granulomatous conjunctivitis and when examining a lesion of the eyelid resembling a squamous cell carcinoma or atypical papilloma.

Adult↗
PubMed1992

Overview of the corneal toxicity of surgical solutions and drugs: and clinical concepts in corneal edema.

Surgical solutions and drugs are important in ocular surgery. These include irrigating solutions, viscoelastic substances, mydriatics and miotics, and a growing number of other agents designed to enhance intraocular surgery and its outcome. Potential for damage to the corneal endothelium and other tissues is related to the chemical composition, pH, and osmolality of the irrigating solutions that bathe tissues. Quality balanced salt solutions (BSS) are usually safe for use as an intraocular solution in patients with normal corneal endothelium. If prolonged irrigation times are expected, or the patient already has decompensated endothelium, i.e., primary or secondary endotheliopathy, the use of a "complete" BSS solution is indicated to minimize damage. Intraocular sulfite-containing epinephrine may cause severe corneal edema and should be avoided, or if used, be well diluted. Sulfite-free epinephrine solution is now available and does not cause the endothelial toxicity that one may see with sulfite-containing epinephrine solutions. Current formulations of acetylcholine and carbachol used as miotics in surgery have been evaluated in humans and caution is recommended in using acetylcholine solutions intracamerally in patients with already decompensated endothelium. Chondroitin sulfate, hydroxypropyl methylcellulose, and sodium hyaluronate are non-toxic to animal endothelial cells under conditions analogous to cataract extraction in humans but can be toxic to endothelium if there is continued contact with endothelium for hours. Chondroitin sulfate has been shown to have more of a protective effect in mechanical pseudophakos trauma probably because of its cohesiveness and tendency to coat the endothelium. Viscoelastics cause a significant rise in intraocular pressure of > 30 mm Hg in 3-10% of patients. Very high intraocular pressures are often seen postoperatively after viscoelastic use surgically in patients who preoperatively have a history of ocular hypertension or glaucoma.

Cell Count↗
PubMed1992

The role of viscoelastics, cannulas, and irrigating solution additives in post-cataract surgery corneal edema: a brief review.

Corneal clarity is dependent upon maintenance of the corneal endothelial barrier and pump. Mechanical trauma is usually considered to be the most significant factor in corneal endothelial damage during cataract surgery resulting in postoperative corneal edema. However, corneal decompensation out of proportion to the degree of trauma seen during surgery does occur. These cases of unexpected corneal edema can often be traced to unrecognized preoperative endothelial dysfunction or to toxicity of intraocular medications used during surgery. This paper reviews the role of viscoelastics in reducing surgical trauma, their toxicity, and the risks of toxicity inherent in the use of re-usable cannulas and irrigating solution additives. Disposable cannulas should be used whenever possible. The use of re-usable cannulas with viscoelastics is highly likely to result in toxic residues being introduced onto the eye, and must be avoided. Irrigating solution additives should be tested with in-vitro human donor cornea perfusions prior to clinical use.

Cataract Extraction↗
PubMed1992

Infectious conjunctivitis.

This article is designed to aid the clinician in the diagnosis of bacterial and viral conjunctivitis by evaluating a wide variety of infectious causes of conjunctivitis. The work-up, including techniques of examination and pertinent laboratory studies, is discussed. Clinical features of each type are covered at length and specific therapy for each is included.

AIDS-Related Opportunistic Infections↗
PubMed1991

Insights from experimental data on ciprofloxacin in the treatment of bacterial keratitis and ocular infections.

Ciprofloxacin is a potent fluoroquinolone antibiotic with in vitro activity against many significant gram-positive and gram-negative ocular pathogens. A review of the experimental studies of this antibiotic shows bactericidal activity, a broad antimicrobial spectrum, and a low incidence of resistance. The growing body of experimental data supports the effectiveness of ciprofloxacin in the treatment of experimental keratitis and suggest that it be evaluated further in ocular infections.

Bacterial Infections↗
PubMed1990

Efficacy and safety of mercuric oxide in the treatment of bacterial blepharitis.

A double-masked, placebo-controlled, randomized study was done to assess the safety and clinical and quantitative microbiologic efficacy of 1% mercuric oxide (yellow) ophthalmic ointment in the treatment of eyelid infections, i.e., bacterial blepharitis. A total of 39 patients with bacterial counts and clinical signs indicative of eyelid infection were treated twice daily for 7 days. Clinical biomicroscopic examination and quantitative microbiologic cultures were done just prior to initiation of treatment and again on days 3 and 7. Statistical analysis revealed a significant improvement in the clinical signs, bacterial count, cure rate, and improvement rate for subjects taking the active medication, compared with those taking the placebo on days 3 and 7. In addition, the medication was well tolerated.

Adult↗
PubMed1989

Penetrating keratoplasty and intraocular lens exchange for pseudophakic bullous keratopathy associated with a closed-loop anterior chamber intraocular lens.

We reviewed the records of 20 consecutive eyes with pseudophakic bullous keratopathy associated with a closed-loop anterior chamber lens that underwent penetrating keratoplasty, total anterior vitrectomy, and anterior chamber intraocular lens exchange. On reexamination, all corneal grafts had remained clear during an average follow-up period of 15 months (range, four to 45 months). Seven eyes (35%) attained a visual acuity of 20/40 or better with spectacle correction; however, 15 of 20 eyes (75%) attained a best-corrected visual acuity of 20/40 or better using a pinhole and a gas-permeable contact lens. In five eyes visual acuity was 20/400 or poorer because of cystoid macular edema, as documented by fluorescein angiography, age-related macular degeneration, or optic atrophy. Localized, minimal peripheral anterior synechiae were present on gonioscopy in seven eyes. The one-piece flexible anterior chamber lens implants used for exchange appeared to be well tolerated in this series of patients.

Aged↗
PubMed1989

Filter-culture technique using amoeba saline transport medium for the noninvasive diagnosis of Acanthamoeba keratitis.

Acanthamoeba, a common free-living amoeba, is increasingly incriminated as a cause of keratitis and corneal ulceration. Between March 1986 and July 1988, specimens from seven patients submitted by ophthalmologists to the City of Milwaukee Health Department's Bureau of Laboratories were culture positive for Acanthamoeba. All patients were contact lens wearers. The specimens were transported at ambient temperature in amoebasaline (5.0 mL) and filtered through 13 mm 0.22 microns cellulose filters. The filters were then plated in cocultivation with Escherichia coli on nonnutrient agar and had positive results for Acanthamoeba in two to five days. Contact lens cases were culture positive for Acanthamoeba in three instances. These results indicate that corneal scraping in amoeba saline transport medium can provide an effective way to diagnose Acanthamoeba keratitis when direct culture of such specimens is not possible.

Acanthamoeba↗
PubMed1985

Corneal organ cultures in tyrosinemia release chemotactic factors.

Corneal inflammation with subsequent scarring and blindness occurs in the inherited human metabolic disease tyrosinemia type II, yet putative inflammatory mediators in this disorder and in the avascular cornea in general are poorly defined. In a Tyr-fed rat model of tyrosinemia type II, intracellular crystals, presumably Tyr, are hypothesized to be responsible for the increased lysosomal activity observed in corneal epithelial lesions. Because polymorphonuclear leukocytes (PMNs) are seen only at the site of these lesions, we used this model to study humoral mediators released from Tyr-fed rat corneal organ cultures. Only Tyr-fed rats developed stromal edema and linear granular opacities in gray edematous corneal epithelium, compatible with a noninfectious keratitis. Electron micrographs confirmed epithelial edema and showed focal epithelial necrosis with PMN invasion of the stroma. Only Tyr-fed rat corneal culture supernatants contained chemotactic activity that was heat labile and moderately trypsin sensitive. Four peaks with varying amounts of chemotactic activity were found on Sephadex G-75 chromatography. Although the identity of these peaks of activity has not yet been established, we suggest that they may be responsible for the PMN infiltration observed in this model of corneal inflammation.

Amino Acid Metabolism, Inborn Errors↗
PubMed1979

Cryotherapy for experimental Pseudomonas keratitis.

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.

Animals↗
PubMed1979

Comparison of therapeutic routes in experimental Pseudomonas keratitis.

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.

Administration, Topical↗
PubMed1979

Experimental Pseudomonas keratitis in guinea-pigs: therapy of moderately severe infections.

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.

Administration, Topical↗
PubMed1978

Topical tobramycin therapy of experimental Pseudomonas keratitis: an evaluation of some factors that potentially enhance efficacy.

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.

Administration, Topical↗
PubMed1978

Corticosteroid in experimentally induced Pseudomonas keratitis: failure of prednisolone to impair the efficacy of tobramycin and carbenicillin therapy.

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.

Administration, Topical↗
PubMed1978

Trifluridine in resistant human herpetic keratitis.

Patients with active dendritic herpetic keratitis that was unresponsive to topical idoxuridine or vidarabine therapy were treated topically with a 1% solution of trifluridine. The dendritic ulcers healed in an average time of 6.1 days. All patients tolerated the drug well except for one patient in whom a reversible crystalline epithelial keratitis developed.

Adolescent↗