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Biomedical subjects

S I Butrus

Publications and source records attributed to S I Butrus.

33 records · Page 2Linked to original sources
PubMed1989

The contribution of bacterial surface hydrophobicity to the process of adherence of Pseudomonas aeruginosa to hydrophilic contact lenses.

Ten isolates of Pseudomonas aeruginosa obtained from the corneas of patients with Pseudomonas keratitis adhered to soft contact lenses in significantly greater numbers than did six isolates from other body sites (P less than .05). However, there was no predominant serotype among the 10 corneal isolates tested. Isolates grown statically in broth at 37 degrees C formed a pellicle and adhered two times as much to contact lenses as did isolates grown in broth while shaking which did not form a pellicle (P less than .01). The more adherent isolates (grown at 37 degrees C) were shown to be more hydrophobic than the less adherent bacteria (grown at 26 degrees C) by their propensity to accumulate at the interface between hexadecane and saline and their movement into polyethylene glycol from dextran. These corneal isolates agglutinated erythrocytes, a process that was inhibited by dilute solutions (as low as 0.01%) of three commonly used surfactants. These same surfactants inhibited the adherence of Pseudomonas aeruginosa to soft contact lens surfaces by as much as 52%. It is concluded that hydrophobic interactions may significantly contribute to the ability of Pseudomonas aeruginosa to adhere to contact lenses.

Bacterial Adhesion↗
PubMed1988

Importance of limbal examination in ocular allergic disease.

We present three adult patients having classic symptoms of ocular allergy with findings confined to the limbus in all eyes. Findings in the cornea and the rest of the bulbar and tarsal conjunctivae were within normal limits. Case 1 had numerous limbal follicles; Case 2 had limbal chemosis 360 degrees; and Case 3 had superior perilimbal conjunctival injection, chemosis, and micropannus formation. Limbal scrapings from all patients revealed abundant eosinophils. There was marked clinical improvement after topical cromolyn sodium 4% treatment. Since the limbus was the only structure involved, the diagnosis of "allergic limbitis" was made. We feel that the limbus is an overlooked structure during ocular examination. As in our three cases, the limbus may be the only area involved in ocular allergy. A careful examination of the limbus may provide important clues for the diagnosis of many ocular inflammatory conditions.

Adult↗
PubMed1987

Carbohydrate deposits on the surfaces of worn extended-wear soft contact lenses.

Three different commercial extended-wear soft contact lenses worn continuously by patients for at least 28 days were stained with fluorescein isothiocyanate-labeled lectins. These lectins detected the presence of alpha-linked or beta-linked D-mannose, D-glucose, D-galactose, L-fucose, N-acetyl-D-glucosamine, N-acetyl-D-galactosamine, and N-acetyl neuraminic acid (sialic acid) on the surfaces of the contact lenses. These saccharides are bound to other sugars that likely account for an integral part of glycoprotein and/or glycolipid deposits on lens surfaces. These tear deposits may contribute to the chemical spoilage of the lens and, furthermore, may serve as specific receptors for pathogenic microorganisms commonly implicated in extended-wear soft contact lens-associated infectious keratitis.

Contact Lenses, Extended-Wear↗
PubMed1987

The adherence of Pseudomonas aeruginosa to soft contact lenses.

The adherence of Pseudomonas aeruginosa to extended-wear soft contact lenses (EWSCLs) may be an important initial step in the pathogenesis of EWSCL-associated infectious keratitis. P. aeruginosa tend to adhere more to worn EWSCLs than unworn EWSCLs (P less than 0.05). Normal tear components such as aqueous solutions of albumin, lysozyme, and lactoferrin all significantly enhance adherence of P. aeruginosa to unworn EWSCLs often by as much as 300%. The presence of a 1% solution of sialic acid in the bathing medium significantly reduces the adherence of P. aeruginosa to both unworn and worn lenses. Inhibition of bacterial adherence could also be achieved with the addition of mucin (which contains terminal sialic acid residues in its major sugar chains). Therefore, selective adherence by P. aeruginosa to a specific sugar (sialic acid) may be important in the initial attachment of the bacterium to soft contact lenses.

Bacterial Adhesion↗
PubMed1987

Topical arachidonic acid: a model for screening anti-inflammatory agents.

Products of arachidonic acid metabolism, prostaglandins and leukotrienes, play an important role in ocular inflammation. In this study, we investigated the efficacies of the cyclo-oxygenase inhibitors (aspirin, indomethacin, and piroxicam) and the lipoxygenase inhibitors (N-hydroxy-arachidonamide (AH) and phenidone) in reducing ocular inflammation induced by arachidonic acid. Administering arachidonic acid topically (0.50% for rabbits and 0.25% for humans) produced a simple model for evaluating the effects of inhibitors on prostaglandins. In rabbits, aspirin, piroxicam and indomethacin all blocked lid closure and chemosis significantly. In humans, aspirin and indomethacin significantly blocked arachidonic acid-induced conjunctival injection. Neither AH nor phenidone blocked any of the signs of ocular inflammation in rabbits or humans. Further testing of phenidone in the presence of the calcium ionophore, ionomycin, also proved negative. Species specificity in arachidonic acid metabolism may account for the different results in humans and rabbits. This model may be a useful tool for comparing the relative efficacies of topical cyclo-oxygenase inhibitors in treating ocular problems.

Administration, Topical↗
PubMed1986

Blocking Candida adherence to contact lenses.

The adherence of microorganisms to contact lenses may be an important initial step in the pathogenesis of contact lens-associated infectious keratitis. Using a strain of Candida albicans whose interaction with various polymers has been well characterized we systematically investigated the adherence of this pathogen to hard hydrophobic and soft hydrophilic extended-wear contact lenses. Yeasts adhere to the hydrophobic lenses in direct proportion to the wetting angle of the lens whereas yeasts adhere to the hydrophilic lenses in direct proportion to the water content of the lens. Tear proteins such as albumin, lactoferrin, and lysozyme in addition to fibronectin enhance yeast adherence to both types of lenses (P less than 0.01). Concanavalin A reduces adherence of yeasts to both lens types (P less than 0.01). Among tear components however, only mucin (0.5%) consistently reduced yeast adherence to both lens types. Hydrophilic extended wear lenses worn for at least 28 days by normal patients consistently had greater adherence of yeasts than unworn lenses of the same type, often as much as ten-fold or greater yeasts/mm2 of lens surface area (P less than 0.05). These investigations indicate that tear components both in solution and adsorbed to the lens surface enhance microorganism adherence to contact lenses.

Candida albicans↗
PubMed1985

Ocular abnormalities and renal disease: a review.

The eye is a mirror that reflects pathologic changes occurring in many organs. The present paper presents eye changes in renal disease including hereditary progressive nephritis, cystic disease of the kidney, cystinosis, and diffuse mesangial sclerosis. It also touches on these changes in some syndromes with major renal involvement.

Child, Preschool↗
PubMed1984

Tolerance and absence of rebound vasodilation following topical ocular decongestant usage.

Commercial preparations of two topical ophthalmic vasoconstrictors were evaluated for whitening ability, duration of action, tolerance, and rebound vasodilation in 11 normal volunteers. Both 0.02% naphazoline HCI and 0.05% tetrahydrozoline HCI significantly reduced baseline redness after a single use (Part I); however, naphazoline produced significantly more whitening than did tetrahydrozoline. Only naphazoline retained its whitening ability after ten days (Part II). The level of redness remained significantly below baseline for eight hours after a single use of either vasoconstrictor and for six hours after multiple use of naphazoline. The diminished effectiveness of tetrahydrozoline after the ten-day test period may encourage its overuse. Neither vasoconstrictor produced rebound vasodilation after discontinuation of use.

Drug Evaluation↗
PubMed1984

Vernal conjunctivitis in the hyperimmunoglobulinemia E syndrome.

Hyper-IgE syndrome (HIE) appears to be related to an immunoregulatory imbalance characterized by severe deficiency of suppressor T cells, elevated levels of IgE antibodies, and repeated infection of various organ systems. We report the association of HIE syndrome in two definite cases and one probable case of vernal conjunctivitis. This association suggests that T cell-mediated imbalance may be one factor in the pathogenesis of vernal conjunctivitis.

Adolescent↗
PubMed1983

Aspirin therapy in vernal conjunctivitis.

Prostaglandin D2 is a secondary mast cell mediator that causes redness, chemosis, mucous discharge, and eosinophil chemotaxis in the eye. It may play an important role in allergic ocular disease. Although histamine is a key mediator of allergic inflammation, antihistamine therapy provides only symptomatic relief. We added aspirin therapy to the treatment regimen of three patients with vernal conjunctivitis. Aspirin acetylates the enzyme cyclooxygenase, thereby preventing the formation of prostaglandin D2. Within two weeks after initiation of aspirin therapy, we noted dramatic improvement in conjunctival and episcleral redness and resolution of keratitis and limbal infiltration. We recommend a trial of oral aspirin as adjunctive therapy for intractable cases of vernal conjunctivitis.

Adolescent↗