Showing papers by "Gottfried O. H. Naumann published in 2006"

Clusterin Deficiency in Eyes with Pseudoexfoliation Syndrome May Be Implicated in the Aggregation and Deposition of Pseudoexfoliative Material

Abstract: Purpose To determine the role of the extracellular chaperone clusterin in the pathophysiology of pseudoexfoliation (PEX) syndrome/glaucoma, which is characterized by the stable deposition of abnormal extracellular fibrillar material in anterior segment tissues. Methods Real-time PCR, in situ hybridization, and immunohistochemistry were applied to analyze the mRNA and protein expression of clusterin in PEX eyes of patients without and with glaucoma and to compare them with eyes of patients with primary open-angle glaucoma and angle-closure glaucoma and with normal control eyes. Aqueous levels of clusterin were determined by Western blot analysis. Real-time PCR and Western blot analysis were used to study the effect of TGF-beta1, which is significantly increased in the aqueous humor of PEX eyes, on clusterin expression by nonpigmented ciliary epithelial cells in vitro. Results Clusterin mRNA was ubiquitously expressed in most ocular cells and tissues, particularly in the epithelium of ciliary processes, whereas the protein was mostly located to extracellular structures, such as ocular basement membranes and stromal fibers. Real-time PCR and in situ hybridization displayed significant downregulation of clusterin mRNA in all anterior segment tissues of PEX eyes, irrespective of the presence or type of glaucoma, compared with normal and glaucomatous control eyes, whereas posterior segment tissues did not show any differential expression. A generally decreased immunoreactivity, but a prominent binding of clusterin to all PEX deposits, could be observed in ocular tissues of PEX eyes. Clusterin levels in aqueous humor were significantly reduced in eyes of patients with PEX syndrome compared with normal and glaucomatous control eyes. The expression of clusterin mRNA and protein in nonpigmented ciliary epithelial cells was significantly downregulated by TGF-beta1 in vitro. Conclusions Considering the known role of clusterin as a highly efficient extracellular chaperone, its deficiency in the anterior segment of PEX eyes may promote the stress-induced aggregation and stable deposition of the pathologic extracellular matrix product characteristic of PEX syndrome.

Histologic and ultrastructural changes in corneas with granular and macular dystrophy after excimer laser phototherapeutic keratectomy.

Abstract: Purpose The histologic changes after phototherapeutic keratectomy (PTK) in corneas with granular and macular dystrophy were studied. Methods We studied 3 corneas of 2 patients (1 granular, 2 macular dystrophy), who underwent penetrating keratoplasty (PK) at 0.8, 2.16, and 3.25 years after PTK; and 11 corneas (controls) from 10 PK patients (5 granular, 6 macular dystrophy) by light microscopy and by transmission electron microscopy. PTK was performed by using the Asclepion-Meditec MEL 60 excimer laser. Results After PTK the epithelium (15-40 versus 5-100 microm), and the upper stromal collagen lamella thickness (50-75 versus 50-100 microm) were less irregular than for the controls. In 1 eye (macular dystrophy) 10 months after PTK an acid mucopolysaccharide-positive band was detected in the subepithelial stroma, which could be removed by hyaluronic acid digestion. This fact suggests that it was "haze" formed after PTK, rather than a subepithelial recurrence of the dystrophy. All PTK corneas had deposits in the mid- and posterior stroma. Concerning controls, deposits were detected under the epithelium in all corneas. Electron microscopy of the study corneas revealed a mostly continuous basal lamina, occasionally forming projections into the subepithelial stroma, and large numbers of well-developed hemidesmosomes (5.2 +/- 0.8 per microm membrane length) present at greater density than in the controls (3.5 +/- 0.8). Conclusions In stromal dystrophies, PTK was effective in removing large subepithelial stromal plaques. There were no subepithelial recurrences, and hemidesmosome density was increased.

Long-term refractive and visual outcome after penetrating keratoplasty only versus the triple procedure in Fuchs' dystrophy.

Abstract: Background Long-term refractive and visual outcome after penetrating keratoplasty (PK) only and the triple procedure in eyes with Fuchs' endothelial dystrophy were assessed and compared.

Intra-individual variability of penetrating keratoplasty outcome after excimer laser versus motorized corneal trephination.

Abstract: PURPOSE: To assess the intra-individual variability of outcomes after penetrating keratoplasty by comparing mechanical and nonmechanical corneal trephination. METHODS: Fifteen patients (30 eyes, 16 with keratoconus and 14 with Fuchs' dystrophy; median age at penetrating keratoplasty 56.3/53.5 years) were assessed whose trephination was performed using a motor trephine in one eye and the 193-nm excimer laser (MEL 60, Carl Zeiss-Meditec) in the other eye by one experienced surgeon. Subjective refractometry, standard keratometry, and corneal topography were used to assess best spectacle-corrected visual acuity (BSCVA); spherical equivalent refraction; keratometric and topographic central corneal power; refractive, keratometric, and topographic astigmatism; surface regularity index; surface asymmetry index; and potential visual acuity preoperatively, before first suture removal (at 1 year), and at last available follow-up after final suture removal but before additional surgery (1.3 and 1.9 years, respectively). RESULTS: Before first suture removal BSCVA was significantly higher (0.7 vs 0.5; P=.008) after excimer laser trephination. At the end of follow-up, refractive/ keratometric/topographic astigmatism (2.20/2.10/2.40 diopters [D] vs 5.00/6.00/7.10 D) and surface regularity index (0.8 vs 1.1) were significantly lower (P=.02, P=.005, P=.01, and P=.03, respectively) and potential visual acuity was significantly higher (0.9/0.6; P=.02) after excimer laser trephination. CONCLUSIONS: During long-term follow-up, all-sutures-out postkeratoplasty astigmatism and surface regularity are superior in the eye where nonmechanical excimer laser was applied in contrast to the fellow eye with motor trephination in the same individual.

Corneal Curvature after Penetrating Keratoplasty before and after Suture Removal: A Comparison between Keratoconus and Fuchs’ Dystrophy

Abstract: Purpose: To assess the differences concerning corneal curvature and visual acuity after penetrating keratoplasty (PKP) comparing keratoconus (KC) and Fuchs’ dystrophy (FUCHS).