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Biomedical subjects

D C Gritz

Publications and source records attributed to D C Gritz.

26 records · Page 2Linked to original sources
PubMed1991

Histochemical localization of superoxide production in experimental autoimmune uveitis.

Although the presence and role of oxygen reactive species in uveal inflammation is the subject of intense investigation, there is little direct evidence that oxygen metabolites are present at the site of inflammation. We used the nitroblue tetrazolium test for superoxide to determine production of this oxygen reactive species in experimental autoimmune uveitis (EAU). The choroidal tissues of animals with this disease contained intracellular, blue-staining granules. Most of the positive staining cells appeared to be polymorphonuclear leukocytes. This localization of superoxide in EAU is further evidence of the generation of oxygen reactive species in uveal inflammation.

Animals↗
PubMed1991

Chemotactic activity of the peroxidized retinal membrane lipids in experimental autoimmune uveitis.

We investigated the mechanism for amplification of intraocular inflammation in rats with experimental autoimmune uveitis by examining the chemotaxis potentials of peroxidized lipids extracted from the retinas. Utilizing thin layer chromatography, we found that the peroxidized products isolated from the inflamed retinas were fatty acid hydroperoxides that corresponded to the autooxidized products from commercial methyl docosahexaenoate, with Rf values ranging from 0.30 to 0.37. These were not demonstrated in similar preparations from normal retinas or in unoxidized docosahexaenoate. Boyden chamber assay revealed that the hydroperoxides isolated from inflamed eyes and the products of oxidized methyl docosahexaenoate possessed significantly higher chemotactic activity than did the retinal lipids isolated from normal eyes (P less than 0.01). These findings may help to explain the mechanism of inflammatory amplification induced by peroxidized retinal lipids that is seen in this animal model of uveitis.

Animals↗
PubMed1990

Topical anti-inflammatory agents in an animal model of microbial keratitis.

Topical steroids potentiate Pseudomonas keratitis in the absence of concomitant antibiotic therapy. The effects of other anti-inflammatory agents on microbial keratitis are unknown, but if these agents do not intensify the infection, they may be useful in the initial management of microbial keratitis by limiting ulceration and thus the size of the resultant corneal scar. In rabbit models of untreated Pseudomonas keratitis and pneumococcal keratitis, topical 1% prednisolone phosphate, 0.03% flurbiprofen sodium, and vehicle were applied hourly. In cases of Pseudomonas keratitis, prednisolone worsened the clinical disease, and flurbiprofen further worsened the disease. When combined with effective antibiotic therapy, neither anti-inflammatory agent worsened the disease. In pneumococcal keratitis, neither anti-inflammatory agent worsened the disease. Topical anti-inflammatory agents should be used with caution in cases of microbial keratitis at least until effective antibiotic therapy has been instituted.

Administration, Topical↗
PubMed1990

Topical ultraviolet light-absorbing chromophore protects against experimental photokeratitis.

Ultraviolet radiation may play a causative role in a number of human ocular and dermatologic conditions; reduction of environmental UV light exposure may decrease their incidence. We investigated the effects of two different UV light-absorbing chromophores, octyl methoxycinnamate (Parsol-MCX) and butyl methoxydibenzoylmethane (Parsol-1798) on corneal UV light transmittance, and evaluated topically applied Parsol-MCX for its protective effect against experimental UV light-induced keratitis in New Zealand white rabbits. Both Parsol-1789 (UV-A light absorber) and Parsol-MCX (UV-B light absorber) are well tolerated by New Zealand white rabbit eyes. Pretreatment with a single drop of Parsol-MCX reproducibly protected against UV light-induced keratitis, apparently by absorbing greater than 75% of UV-B (peak wavelength, 308 nm) irradiation.

Administration, Topical↗
PubMed1987

Ultrastructural characteristics of proliferative tissue in retinopathy of prematurity.

We examined the histologic and ultrastructural characteristics of 27 membranes (from 18 patients) removed during vitreous surgery for partial and total retinopathy of prematurity. In membranes removed anteriorly from a child with active disease, we found vessels that had characteristics of developing neovascularization. In the membranes from older infants with inactive disease (16 patients), glial cells were common and vessels, if present, had more mature characteristics. Retinal glial cells (presumably Müller cells) were seen fragmenting the internal limiting lamina and migrating into the overlying vitreous by projecting long microvilli into the vitreous cavity. Anterior membranes (13 patients), particularly in active disease, were likely to contain vessels, whereas posterior membranes (five patients) were more often avascular and were composed of glial cells.

Basement Membrane↗
PubMedDate not supplied

Ultraviolet radiation for the sterilization of contact lenses.

Two sources of ultraviolet (UV) radiation with peak wavelengths in the UV-C or UV-B ranges were compared for their ability to sterilize contact lenses infected with Pseudomonas aeruginosa, Streptococcus pneumoniae, Acanthamoeba castellani, Candida albicans, and Aspergillus niger. Also examined was the effect of prolonged UV light exposure on soft and rigid gas permeable (RGP) contact lenses. The UV-C lamp (253.7 nm, 250 mW/cm2 at 1 cm) was germicidal for all organisms within 20 minutes but caused destruction of the soft lens polymers within 6 hours of cumulative exposure. UV-C caused damage to RGP lenses in less than 100 hours. The UV-B lamp (290-310 nm, 500 mW/cm2 at 1 cm) was germicidal for all organisms tested (except Aspergillus) with a 180-minute exposure and caused less severe changes in the soft lens polymers than did the UV-C lamp, although cumulative exposure of 300 hours did substantially weaken the soft lens material. RGP materials were minimally affected by exposure to 300 hours of UV-B. Ultraviolet light is an effective germicidal agent but is injurious to soft lens polymers; its possible utility in the sterilization of RGP lenses and lens cases deserves further study.

Acanthamoeba↗
PubMedDate not supplied

Comparison of a computer-assisted laser pachometer with two ultrasonic pachometers in normal corneas.

A computer-assisted laser pachometer was compared with two ultrasonic pachometers for intra- and interobserver error. Two observers each performed two examinations at 11 predetermined locations on the corneas of six subjects. The laser pachometer was found to have intra- and interobserver errors comparable to both of the ultrasonic pachometers. By performing multiple examinations on three subjects, the laser pachometer was found to have an average standard deviation of +/- 0.012 mm. Unlike ultrasonic pachometers, the laser pachometer has the advantage of being a noncontact method of evaluating corneal thickness, and does not require topical anesthesia; the trauma and anesthesia might alter corneal thickness by inducing epithelial edema. The nasal cornea was found to be slightly thicker than the temporal cornea in most patients. Lid closure for three hours caused a consistent thickening (about 6.3%) of central and peripheral cornea.

Adult↗