摘要:

In some patients with severe burns, major problems were delayed regeneration of the surface epithelium, extensive ulceration of the sclera near the limbus, subsequent corneal ulceration, and subconjunctival scarring. Human tissues surrounding ulcerations in severe eye burns were obtained from surgical interventions in 12 such patients. High activities of the lysosomal marker enzyme N-acetylglucose aminidase were found. As is known from histological examinations, these tissues do not represent regeneration of conjunctiva, but rather inflammatory proliferation. The tissues adjacent to corneoscleral ulceration release large amounts of lysosomal destructive enzymes. The rather simple assay of the activity of the N-acetylglucose aminidase proved useful in clinical cases to assess the activity of the inflammation of eye burns and to estimate the efficacy of the therapy applied.

ISSN:0277-3740    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Chemical burning of the external eye by a strong acid or alkali often results in symblepharon formation despite conventional therapy. We report a case with application of a Megasoft Bandage Lens to prevent symblepharon reformation after surgical correction. Complete epithelial healing was established after 3 months, when the lens could be removed. No complications were found with this lens. No symblepharon reformation occurred 26 months after the surgical reconstruction.

ISSN:0277-3740    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Pseudomonas aeruginosa adherence in vitro to perfilcon A (ionic, 71% H2O) extended wear soft contact lenses— both new and after 7 days of continuous wear on closed rabbit eyes—was found to be related directly to the bacterial concentration in the contaminating solution. Thirty rabbits wore perfilcon A lenses for 7 days with complete lid closure to mimic contact lens overwear. After 7 days, conjunctival cultures showed no growth of pathogens, but all corneas had developed epithelial cell exfoliation and/ or epithelial defects and stromal edema. The lenses were then incubated in various concentrations (107, 106, 105, 104, and 102colony-forming units per milliliter or saline control; n=5/group) ofP. aeruginosa suspensions and replaced on their respective corneas with tarsorrhaphies for an additional 48 h. By day 9, corneal thickness had increased significantly, andP. aeruginosa keratitis had developed in 13 of 25 bacterially exposed eyes but not in 5 control eyes. Although with decreasingP. aeruginosa concentration the prevalence of ulcerative microbial keratitis also decreased, the initial concentration of bacteria or the initial extent of soft contact lens-induced corneal damage had no influence on the ultimate clinical severity of the disease.

ISSN:0277-3740    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

The emergence of cross-resistance to various antiviral drugs was investigated both in vivo and in vitro for herpes simplex virus type 1 (HSV1) resistant to idoxuridine IUdR 0.24%) obtained by seven successive passages from P0 to P7) in rabbit keratitis treated by IUdR. The viral population obtained at the seventh IUdR passage P7) showed an activity of the thymidine kinase (TK) reduced to 5.6% of the parental strain (PO); moreover, most of the clones of P7 showed an altered TK phenotype determined by the [l25I]iododeoxycytidine (IDC) procedure. In rabbit keratitis, IUdR-resistant viral population P7 showed cross-resistance to bromovinyl desoxyuridine (BVDU) (0.5%) and to acyclovir (ACV) (3%). Under trifluorothymidine (1%) treatment, P7 showed an intermediate sensitivity. HSV1 at P7 remained sensitive to adenine arabinoside (Ara A) (3%) and to dihydroxy-propoxymethylguanine used at high concentration (3%). The in vitro sensitivity determination to various antiviral drugs was investigated by dye-uptake assay for the initial viral population PO and for HSV1 collected under IUdR treatment at the third (P3) and the seventh (P7) passages. Cross-resistance to TK-dependent drugs, such as IDC, BVDU, and ACV were found at P7. P7 remained sensitive to Ara A and to phosphonoformic acids antiviral drugs known not to be dependent on viral TK.

ISSN:0277-3740    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Suction rings are used to stabilize the globe during refractive surgery procedures. This study investigates the changes in ocular pressure and corneal curvature induced by a suction ring on rabbit corneas. A sharp rise in intraocular pressure, to as high as 80 mm Hg, followed by a time-dependent decline was found. The application of this ring also caused astigmatic changes in the cornea. Corneal thickening was also encountered. These findings have implications for possible artifactual changes during photorefractive keratoplasty and raise the possibility of intraocular pressure-induced damage in susceptible individuals.

ISSN:0277-3740    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Intrastromal corneal crystals developed in 11 of 49 monkey eyes with hydrogel intracorneal lenticules followed over a 4 year period. All of the eyes, except one, underwent synthetic keratophakia via a microkeratome incision. The diagnosis of crystal formation was initially made by slit-lamp examination and confirmed with specular microscopy (from 21 to 150 days post-hydrogel keratophakia). The crystals were noted to lie in a plane adjacent to the hydrogel lenticule and specular microscopy revealed polychromatic, hyperrefringent crystals with either a rectangular or linear morphology. Prior to intrastromal crystal formation, these corneas developed early postoperative stromal edema (*3 weeks). We hypothesize that early stromal edema in combination with the hydrogel intracorneal lenticule induced the production of lipid crystals by stromal keratocytes.

ISSN:0277-3740    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Human type IV collagen discs were found to support proliferation and adhesion of rabbit corneal epithelial cells in tissue culture. To assess the biocompatibility of this synthetic collagen for epikeratoplasty, seven eyes of seven rhesus monkeys underwent epikeratoplasty with lenticules made of human type IV collagen. Eye rubbing by the animals expulsed two of the lenticules and caused failure of two to epithelialize completely. The remaining three lenticules epithelialized, remained clear, and caused no adverse effects on the eye. Two of these lenticules developed focal areas of subepithelial thinning 3 months postoperatively and the third lenticule has remained stable for 30 months. The presence of epithelial attachment components at the epithelial-lenticule interface was demonstrated by immunolocalization. Histopathologic and ultrastructural examination revealed focal areas of epithelial invasion and degradation of the lenticule. Neutral proteases were detected in the thinning region of one specimen. Human type IV collagen supports epithelialization in vivo and may have potential as a biomaterial for epikeratoplasty, but the stability of the material must be improved.

ISSN:0277-3740    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Keratin-positive fibroblast-like epithelial cells (FLE), isolated from human corneo-scleral-conjunctival rims, were shown to inhibit mitogen-driven (concanavalin A) DNA synthesis by murine thymocytes and splenocytes [lymphoreticular cells (LRC)]. The effect exerted by live cells culture and by their supernatants was caused by factors active across species barriers. Paraformaldehyde-fixed or irradiated cells also suppressed mitogen-induced thymocyte DNA synthesis, but their supernatants manifested no such activity. Interaction between FLE cells and LRC the presence of the mitogen resulted in suppressed cellular activation as evidenced by significantly lowered tetrazolium salt (MTT) reduction in murine thymocytes and splenocytes, suggesting reduced mitochondrial activity. The suppressive effect was seen with live and paraformaldehyde- fixed FLE cells. There was a good correlation between MTT assays and [3H]thymidine uptake experiments. Suppression of MTT reduction in murine thymocytes and splenocytes by intact FLE cells could be reversed by the addition of interleukin-1 (IL-1). Indomethacin prevented FLE-conditioned medium-induced suppression but failed to relieve suppression by whole FLE cells. Thus, suppression of LRC function by FLE cells and their secretions appeared to operate by different mechanisms. One mechanism related to prostaglandins present in FLE cell-conditioned medium, whereas another mechanism appeared to involve cell-membraneassociated factor(s). The findings not only provide additional information on the capability of corneal cells regulate lymphoreticular cells but suggest an important role for IL-1 in the regulation of LRC function and corneal inflammation and immunity.

ISSN:0277-3740    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Eleven patients with blue sclera, limbus-to-limbus corneal thinning, hypermobile joints, and consanguineous parents were examined between January 1983 and September 1991. The clinical diagnosis was consistent with the Ehlers-Danlos syndrome type VI phenotype in all patients. A "halo" sign at the limbus was present in all patients. Corneal rupture occurred in seven patients (nine eyes) either spontaneously or following minimal trauma. Acute hydrops occurred in three patients. Bilateral microcornea was present in one patient and two patients had a unilateral increased corneal diameter as a result of secondary glaucoma after trauma. Peripheral sclerocornea was present bilaterally in five patients. Curvature abnormalities included cornea plana, keratoconus, and keratoglobus.

ISSN:0277-3740    

出版商:OVID    

年代:1993

数据来源: OVID

摘要:

Intolerance to rigid contact lenses in keratoconus may occur as a result of epithelial pathology or a suboptimal fitting. The application of a soft lens as a bandage makes it possible to tolerate a rigid lens over it. This study gives the results of 40 eyes in 26 patients who were consecutively fitted with a new aspheric combination lens. Thirty-five eyes (87.5%) showed no discomfort, acceptable wearing time, and visual acuity. Four of these eyes showed an improvement of the corneal condition, eliminating the need for a further piggyback wearing system. Failures were found in five eyes (12.5%), which were caused by giant papillary conjunctivitis (two eyes), severe keratoconus (one eye), difficulty in lens handling and lack of motivation (two eyes). The successful use of an aspheric piggyback combination lens in rigid lensintolerant keratoconus may preclude early surgical therapy.

ISSN:0277-3740    

出版商:OVID    

年代:1993

数据来源: OVID