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Karl Ulrich Bartz-Schmidt

Publications and source records attributed to Karl Ulrich Bartz-Schmidt.

At least 19 recordsLinked to original sources
PubMed2007

Effects of the protein tyrosine kinase inhibitor genistein and taurine on retinal function in isolated superfused retina.

BACKGROUND: Genistein has the potential to act as an intraocular antiangiogenic agent. Its therapeutical use, however, is limited by toxic side effects on the retina. This study was designed to evaluate the simultaneous use of taurine as a neuroprotective drug. METHODS: Bovine retinas were isolated and perfused with an oxygen-preincubated nutrient solution. The electroretinogram (ERG) was recorded as a transretinal electrical potential using Ag/AgCl electrodes. At stable ERG amplitudes, genistein at concentrations of 11, 37, and 150 microM was added to the nutrient solution for 45 min, in the absence or presence of taurine (3 mM). Thereafter, the retina was reperfused with the nutrient solution for another 100 min. The percentage of b-wave reduction during genistein and genistein/taurine application was calculated. RESULTS: The b-wave amplitude was reduced by a smaller amount during the application of genistein (11 and 37 microM) in the presence of taurine compared with genistein alone. For both, genistein/taurine and genistein alone the b-wave recovered completely during the wash-out of the drugs. However, during the application of the highest tested concentration of genistein (150 microM), taurine did not protect completely, leading to an irreversible b-wave reduction. CONCLUSIONS: The adjuvant use of taurine reduces the genistein-induced retinal toxicity to a certain degree. However, the protective effect of taurine is limited and there is only a narrow therapeutic index for a combined intravitreal administration of genistein in coapplication with taurine to inhibit pathological ocular neovascularization.

Animals↗
PubMed2007

Compound subretinal prostheses with extra-ocular parts designed for human trials: successful long-term implantation in pigs.

BACKGROUND: Subretinal implants aim to replace photoreceptor function in patients suffering from degenerative retinal disease like retinitis pigmentosa by topically applying electrical stimuli in the subretinal space. This study-as a last step before upcoming human trials-explored a newly developed surgical technique for permanent implantation of complex subretinal implants with extra-ocular parts. METHODS: The implant consisted of a microphoto-diode array (MPDA) with 1550 electrodes and a 4x4 array of gold electrodes for direct electrical stimulation; both were mounted onto a polyimide foil for transscleral placement into the subretinal space. The foil carried connection lanes to a silicone cable that was implanted under the skin and led to a stimulator box in the animal's neck. Surgery was performed in 11 domestic pigs. Improved vitreo-retinal surgical technique consisted of a 180 degrees peripheral retinotomy and use of diathermy to penetrate the choroid in order to avoid choroidal haemorrhage. Subretinal forceps were used to place the implant safely onto the retinal pigment epithelium before the retina was flattened, peripheral laser photocoagulation was applied and the eye was filled with silicon oil. The implant was stabilized by a scleral fixation patch, use of a metal clamp with bone screws on the animal's skull and a tissue ring under the animal's skin in the neck. Behaviour was observed in the freely moving animals after direct subretinal electrical stimulation and funduscopy, optical coherence tomography, fluorescein angiography and histology were performed. RESULTS: All implants were successfully placed subretinally. In three animals a proliferative vitreo-retinopathy was observed after approximately 2 weeks. Otherwise, funduscopy and OCT demonstrated complete retinal attachment and FA showed no retinal vascular abnormalities over and around the implant. The animals showed clear behavioural reactions to electrical stimulation over the whole examination period. Histological examination failed to show any voltage-induced alteration in the cellular architecture of the retina overlying the stimulation electrodes. CONCLUSIONS: This study demonstrates the feasibility of a new surgical procedure for highly safe and controlled implantation of complex subretinal devices with extra-ocular parts. The new implant design proved to be safely implantable in free-moving pigs for an observation period of 4 weeks.

Animals↗
PubMed2006

A case of cutaneous melanoma metastatic to the vitreous cavity: possible pathomechanism and review of the literature.

BACKGROUND: Isolated vitreous metastases are extremely rare and the pathogenesis of metastasis is still unclear. Here we present the detailed description of the disease progression in a 68-year-old patient with vitreous seeding of a metastatic cutaneous melanoma beginning at a very early stage. METHODS: Interventional case report and review of the literature. RESULTS: The initial retrohyaloidal metastatic lesion was identified adjacent to a small epiretinal hemorrhage. As the disease progressed golden brown spherules appeared in the posterior vitreous emanating from the area of the lesion. Further progression led to a dense metastatic infiltration of the entire vitreous cavity and a decline of the visual acuity to 20/1200. Diagnostic and therapeutic pars plana vitrectomy was performed to confirm the diagnosis and preserve the eye and useful vision. CONCLUSIONS: For the first time the formation of vitreous metastases derived from cutaneous melanoma was carefully studied beginning at a very early stage. This made it possible to analyze the rare mechanism of vitreous metastasis, which has not been conclusively known till now. The features of metastatic cutaneous melanoma to the vitreous are discussed in context of a review of the literature that resulted from the study of 17 patients with 22 affected eyes.

Aged↗
PubMed2006

Dose, timing and frequency of subconjunctival 5-fluorouracil injections after glaucoma filtering surgery.

BACKGROUND: Although adjunctive postoperative 5-fluorouracil (5-FU) injections are known to improve the success rate of glaucoma surgery, it is still unknown what dose, timing and frequency of application will give the best results with respect to the inhibition of postoperative scarring and intraocular pressure regulation. We therefore designed the following retrospective investigation. METHODS: We studied 172 eyes from 172 patients who had undergone trabeculectomy with adjuvant 5-FU-therapy. Variations of dosage, timing and frequency were analysed retrospectively. Surgery was defined as a complete success when the patient reached an intraocular pressure under 21 mmHg and a reduction of 20% 12 months after the operation. A relative success was achieved with these criteria under additional local medication. Not reaching these postoperative criteria for a complete success was classified as failure. RESULTS: On average, adjunctive 5-FU-treatment was started 4.6+/-5.85 days postoperatively. The injections contained between 2 mg and 5 mg FU, and the mean total dose was 26.6+/-13.2 mg (range 5-65 mg). Surgery on 94 patients (54.65%) was classified as "complete success", that on 25 patients (14.53%) was classified as "relative success" and that on 53 eyes (30.81%) was classified as "failure" 12 months (+/-3 months) postoperatively. The best results were obtained when the treatment started on or before the first postoperative day (68.0-71.4% complete success; P<0.05). In contrast, an increase in 5-FU dosage did not result in an increased success rate of trabeculectomy. None of the 172 patients suffered from vision-threatening complications such as endophthalmitis or hypotony maculopathy. CONCLUSION: Early treatment with 5-FU significantly increases the success rates of filtering surgery.

Adult↗
PubMed2006

Muscarinic cholinoceptor-stimulated phosphatidyl inositol pathway in corneal epithelial and endothelial cells.

BACKGROUND: Muscarinic cholinoceptors are distributed widely in both the central and peripheral nervous system. The presence of muscarinic cholinoceptors in corneal tissue is well established. Previous reports have shown that corneal muscarinic cholinoceptors are of the m2 or m4 subtype. However, recent studies have indicated the presence of the m5 muscarinic cholinoceptor subtype in human corneal epithelium and endothelium. The aim of the study was to confirm the presence of the m5 cholinoceptor subtype in bovine corneal epithelium and endothelium and the activation of phosphatidyl inositol pathway by its stimulation. METHODS: Muscarinic m5 cholinoceptor sites, phosphatidyl inositol 4,5-biphosphate, inositol 1,4,5-triphosphate and protein kinase C, were studied using immunocytochemistry and immunofluorescence. Activation of protein kinase C after stimulation of the m5 muscarinic cholinoceptor subtype was measured using the HTS protein kinase C assay kit. RESULTS: Immunocytochemistry/immunofluorescence revealed the presence of the m5 muscarinic cholinoceptor subtype, phosphatidyl inositol 4,5-biphosphate and protein kinase C in bovine corneal epithelial and endothelial cells. In bovine corneal epithelium and endothelium, protein kinase C activity was stimulated by acetylcholine in a dose-dependent manner (P<0.0001). CONCLUSIONS: Our findings indicate that acetylcholine-induced stimulation of muscarinic m5 cholinoceptors activates the phosphatidyl inositol pathway in corneal epithelial and endothelial cells, resulting in increased protein kinase C activity. Further work will be needed to clear the physiologic role of this signaling pathway in corneal epithelium and endothelium.

Acetylcholine↗
PubMed2006

Effect of verteporfin photodynamic therapy on endostatin and angiogenesis in human choroidal neovascular membranes.

AIM: To evaluate the effect of verteporfin photodynamic therapy (PDT) on endostatin with regard to expression of vascular endothelial growth factor (VEGF) in human choroidal neovascular membranes (CNVs) secondary to age-related macular degeneration. METHODS: A retrospective review of an interventional case series of 68 patients who underwent removal of CNV. 29 patients were treated with PDT 3-655 days before surgery. 39 CNVs without previous treatment were used as controls. CNVs were stained for CD34, CD105, Ki-67, cytokeratin 18, endostatin, E-selectin and VEGF. "Predominance score of VEGF over endostatin" (mean) was defined as the difference between VEGF and endostatin staining scores. RESULTS: In four CNVs treated by PDT 3 days previously, PS was significantly higher in the retinal pigment epithelium (mean = 2.5, p = 0.006) and stroma (mean = 2, p = 0.015) than in the control group (mean = 0). At longer post-PDT intervals, PS was significantly decreased in the retinal pigment epithelium (mean = 0, p = 0.019) and stroma (mean = 0, p = 0.015). Proliferative activity was high (p = 0.023), but mostly related to inflammatory cells. PDT did not influence E-selectin expression significantly. CONCLUSIONS: VEGF predominance over endostatin early after PDT might contribute to enhanced angiogenic activity associated with recurrences. Strategies upregulating or replacing endostatin early after PDT might increase the effectiveness of PDT.

Aged↗
PubMed2006

Expression of endostatin in human choroidal neovascular membranes secondary to age-related macular degeneration.

Endostatin is an endogenous angiogenesis inhibitor which requires E-selectin for its antiangiogenic activity. The aim of this study was to investigate the expression of endostatin in human choroidal neovascular membranes (CNV) secondary to age-related macular degeneration (AMD) with regard to vascularization and proliferative activity. An interventional case series of 36 patients who underwent removal of CNV were retrospectively investigated. Thirty-six CNV were analyzed by light microscopic immunohistochemistry for the expression of CD34 (endothelial cells, EC), CD105 (activated EC), Ki-67 (cell proliferation), Cytokeratin 18 (epithelial cells), VEGF (vascular endothelial growth factor), E-selectin and endostatin. Donor eyes (n=7) including one with AMD were used as controls. Endostatin immunoreactivity was present in choroidal vessels of five as well as in the retinal pigment epithelium (RPE)-Bruch's membrane complex of two donor eyes without AMD. In one eye with AMD, endostatin was detected in RPE, Bruch's membrane and choroidal vessels. Ninety-two percent (33/36) of CNV disclosed endostatin staining. RPE-Bruch's membrane complex, choroidal vessels and stroma were positive in 50% (18/36), 72% (26/36), and 78% (28/36) of the membranes, respectively. Both control eyes and CNV expressed all the investigated markers except E-selectin being positive only in membranes. Endostatin, an endogenous angiogenesis inhibitor, is expressed in CNV and its therapeutic up-regulation may be a new strategy in the treatment of neovascular AMD.

Adult↗
PubMed2006

Transscleral diode laser cyclophotocoagulation as primary and secondary surgical treatment in primary open-angle and pseudoexfoliatve glaucoma. Long-term clinical outcomes.

BACKGROUND: Transscleral diode laser cyclophotocoagulation (TDLC) has been used successfully in the treatment of refractive glaucoma. However, little is known about TDLC as a primary or secondary surgical procedure in primary open-angle and pseudoexfoliative glaucoma. METHODS: In a retrospective chart review we analyzed 90 eyes (48 OD/42 OS) in 90 patients (mean age 75 years, range 60-92 years; 51 men/39 woman) with primary open-angle glaucoma (n=66) and pseudoexfoliative glaucoma (n=24) who consecutively underwent TDLC with a minimum follow-up of 24 months. In 24 eyes (26.7%) TDLC was the primary surgical treatment. Mean energy was 80 J (60-92 J). Success was defined as a final intraocular pressure (IOP) between 4 and 18 mmHg, a minimum IOP reduction of 20% and the absence of major complications. RESULTS: The overall success rate was 36.7% after 24 months. A mean of 1.3 procedures was performed per patient. No correlation between age and success rate (p=0.887) or gender and success rate (p=0.895) was seen. There was no significant reduction in antiglaucomatous medication (p=0.208), no significant loss of visual acuity (p=0.324) nor a significant relationship between loss of visual acuity and failure of treatment (p=0.201). In patients with primary open-angle glaucoma the success rate was 40.9% after 24 months; in patients with pseudoexfoliative glaucoma it was 25.0% after 24 months. There was no significant difference between primary open-angle glaucoma and pseudoexfoliative glaucoma (p=0.684). Previous ocular surgery decreased the success probability from 45.8 to 33.3% (p=0.001). Prolonged hypotonia occurred in 1 patient. No phthisis bulbi developed. CONCLUSIONS: Transscleral diode laser cyclophotocoagulation is an effective and safe method not only in the treatment of refractive glaucoma, but also as a primary surgical procedure in primary open-angle and pseudoexfoliative glaucoma. TDLC may be used more widely in glaucoma therapy, although further long-term studies have to confirm these findings.

Aged↗
PubMed2006

Muscarinic acetylcholine receptor subtypes in human corneal epithelium and endothelium.

BACKGROUND: Muscarinic acetylcholine receptors are located throughout the body. The demonstration of muscarinic receptors in corneal tissue has been inconsistent. Using freshly fixed human corneal tissue, we show a complete profile of muscarinic receptor subtypes in human corneal epithelium and endothelium. METHODS: Muscarinic receptor sites were studied using immunocytochemistry, immunofluorescence and immunoblotting. RESULTS: Antibodies to M2, M4 and M5 muscarinic receptor subtypes bound in human corneal epithelium and endothelium. No binding was found for antibodies to M1 and M3 muscarinic receptor subtypes. CONCLUSIONS: Our studies indicate the presence of M2, M4 and M5 muscarinic acetylcholine receptor subtypes in human corneal epithelium and endothelium. These receptors may play a role in the regulation of corneal homeostasis, other functions, like wound healing, or the pathogenesis of corneal diseases.

Adult↗
PubMed2006

Consequences of verteporfin photodynamic therapy on choroidal neovascular membranes.

OBJECTIVE: To examine the impact of photodynamic therapy (PDT) on angiogenesis in human choroidal neovascular membranes with respect to vascular endothelial growth factor (VEGF) expression, proliferation, and vascularization. METHODS: Retrospective review of an interventional case series of 50 patients (50 eyes) who underwent removal of choroidal neovascular membranes. Choroidal neovascularization was secondary to age-related macular degeneration. Twenty patients were treated with PDT 3 to 655 days before surgery. Choroidal neovascular membranes were stained for CD34, CD105, Ki-67, cytokeratin 18, and VEGF. Thirty choroidal neovascular membranes secondary to age-related macular degeneration without previous treatment were used as controls. RESULTS: Specimens without pretreatment disclosed varying degrees of vascularization, proliferative activity, and VEGF expression by different cells. Specimens treated with PDT 3 days earlier showed mostly occluded vessels, damaged endothelial cells, and low proliferative activity. In contrast, specimens excised at later time points after PDT were highly vascularized and proliferating. This chronology was associated with an impressive VEGF immunoreactivity unique to retinal pigment epithelial cells shortly after PDT that also shifted to other cells at later time points. CONCLUSIONS: Photodynamic therapy induces selective vascular damage in choroidal neovascular membranes. The effectiveness and selectivity of this treatment, however, seem to be jeopardized by a rebound effect initiated by enhanced VEGF expression in retinal pigment epithelial cells.

Aged↗
PubMed2006

Expression of VEGF and PEDF in choroidal neovascular membranes following verteporfin photodynamic therapy.

PURPOSE: To examine the impact of photodynamic therapy (PDT) on pigment epithelium derived factor (PEDF) expression in human choroidal neovascularization (CNV) membranes with regard to vascular endothelial growth factor (VEGF) expression. DESIGN: Interventional case series. METHODS: Retrospective review of interventional case series of 42 patients (42 eyes) who underwent removal of CNV. CNV was secondary to age-related macular degeneration (AMD) in all cases. Fifteen patients were treated with PDT, 3 to 246 days before surgery. CNV were stained for CD34, CD105, cytokeratin 18, VEGF, and PEDF. Twenty-seven CNV without previous treatment were used as control. RESULTS: Specimens without pretreatment disclosed varying degrees of vascularization, VEGF, and PEDF expression by different cells. Specimens treated by PDT, three days previously showed mostly occluded vessels lined with damaged endothelial cells (EC). In contrast, specimens excised at later time points after PDT were highly vascularized with healthy EC. This chronology was associated with an impressive VEGF immunoreactivity increased considerably in retinal pigment epithelial cells as well as significantly reduced PEDF expression in EC and stroma. CONCLUSIONS: PDT induces a selective vascular damage in CNV. The effectiveness of PDT, however, seems to be jeopardized by a rebound effect initiated by an enhanced VEGF and reduced PEDF expression in CNV.

Aged↗
PubMed2006

Intracameral bevacizumab for iris rubeosis.

PURPOSE: To determine whether intracameral bevacizumab decreases vascular leakage from iris rubeosis in patients with neovascular glaucoma. DESIGN: Interventional case series. METHODS: The study included six eyes of three patients with secondary neovascular glaucoma due to proliferative diabetic retinopathy (n = 2) or ischemic central retinal vein occlusion (n = 1). All patients received an intracameral injection of 1.0 mg bevacizumab. Morphologic changes and vascular leakage were investigated prospectively by iris fluorescein angiography. RESULTS: Decrease in leakage was detected as early as one day after injection. No inflammation was observed. No relapse was seen within the follow-up of four weeks. CONCLUSION: Intraocular injection of bevacizumab may provide an additional strategy for the treatment of iris rubeosis in neovascular glaucoma.

Aged↗
PubMed2006

Monoamine receptors in human corneal epithelium and endothelium.

PURPOSE: Monoamine receptors are found throughout the body. Reports about the presence of monoamine receptors in the human cornea are inconsistent. METHODS: Immunohistochemistry, immunofluorescence and immunoblotting were used to localize monoamine receptor sites on human corneal epithelium and endothelium. RESULTS: Antibodies to alpha-1, beta-1 and beta-2 adrenergic receptors and to D1-like and 5HT-7 receptors were bound in corneal epithelium. Antibodies to alpha-1, alpha-2A, beta-1 and beta-2 adrenergic receptors and to 5HT-7 receptors were bound in corneal endothelium. CONCLUSIONS: Our data demonstrate the presence of several monoamine receptors in the human cornea. These receptors may play a role in the regulation of fluid transport or corneal homeostasis.

Adult↗
PubMed2006

Instrumentation and technique for delivery of tissue explants to the subretinal space.

PURPOSE: The controlled orientation of subretinal or intraretinal delivery of delicate tissue sheets is a critical problem in retinal transplantation research. METHODS: A surgical device (explant injector) was designed and built for the controlled delivery of tissue explants into the subretinal or intraretinal space via a vitrectomy approach. The technical feasibility was demonstrated in enucleated porcine eyes. RESULTS: Using negative pressure, the injector allows for the fixation of an explant, such as a monolayer of cells cultured on a collagen membrane, on the carrier platform. The sheet can then be placed safely without loss of orientation in the subretinal space. CONCLUSIONS: With the aid of the explant injector, it is possible to deliver an explant with the proper orientation to a precise location in the subretinal space.

Absorbable Implants↗
PubMed2006

Phosphenes electrically evoked with DTL electrodes: a study in patients with retinitis pigmentosa, glaucoma, and homonymous visual field loss and normal subjects.

PURPOSE: To develop an improved, easy, and safe method for reliably eliciting electrical phosphenes and to compare reported perceptions and values of chronaxie and rheobase in healthy individuals and patients with distinct ophthalmic diseases. METHODS: DTL electrodes were used with a four-alternative, forced-choice method to determine psychophysically the strength-duration curves by using the Weiss model of electrical tissue stimulation in 47 subjects: healthy individuals (n = 17; n = 6 under light- and dark-adapted conditions), patients with open-angle glaucoma (n = 9), retinitis pigmentosa (RP; n = 14), amblyopia (n = 3), or homonymous visual field loss (n = 4). RESULTS: In all subjects, thresholds were safely determined without side effects. Subjects reported a homogenous, central, white, steady phosphene. The rheobase was higher in glaucoma and patients with RP than in healthy subjects (0.1129 +/- 0.0314 and 0.6868 +/- 0.1054 vs. 0.0383 +/- 0.0057 mA; P = 0.05 and <0.00001, respectively), and it increased with age (r = 0.51; P = 0.038). The rheobase was lower in light- than in dark-adapted conditions (difference 0.015 mA; P = 0.016). In patients with RP, no correlation was found between rheobase or chronaxie and retinal thickness (in OCT) or number of years after reading loss, but there was a correlation between rheobase and visual acuity (P = 0.014). In patients with RP or glaucoma, no inhomogeneity of phosphenes was reported, but all patients with homonymous visual field loss reported lateralization of the phosphene into the area of visual loss. CONCLUSIONS: Use of DTL electrodes to elicit electrical phosphenes is safe, fast, and reliable. It bears significant advantages over corneal electrodes and provides a valuable tool to elucidate ophthalmologic disease processes and to screen candidates for retinal prostheses.

Adult↗
PubMed2006

Ultrastructural changes after artificial retinal detachment with modified retinal adhesion.

PURPOSE: Artificial retinal detachment is increasingly used in submacular surgery. However, overcoming physiological retinal adhesiveness by subretinal fluid injection is suspected to cause cellular damage and thus to limit visual rehabilitation. This experimental study was designed to examine the ultrastructural changes induced by retinal detachment under vitrectomy conditions and to evaluate factors that reduce adhesiveness and minimize cellular damage. METHODS: Twenty-one pigmented rabbits underwent vitrectomy, and the vitreous cavity was perfused for 10 minutes with various solutions. These included variations in osmolarity (314 and 500 mOsM), Ca(2+) ion concentration (Ca(2+)-supplemented, low Ca(2+), active Ca(2+) deprivation via 1 mM EDTA), temperature (19 degrees C and 34 degrees C), and ischemia (5 minutes). Nonvitrectomized eyes served as the control. Consecutively, an artificial bleb detachment was created underneath the visual streak by injecting 1 mL of buffered saline solution subretinally. Eyes were enucleated within 3 minutes, fixed with 2% glutaraldehyde/0.1 M cacodylate buffer (pH 7.4) containing 100 mM sucrose and processed for transmission electron microscopy and scanning electron microscopy. RESULTS: If a Ca(2+)-containing standard solution was used during vitrectomy, retinal adhesiveness was strong, and a forced bleb detachment caused substantial cellular damage characterized by swollen and fragmented photoreceptor outer segments and disruption of retinal pigment epithelial cells. Use of a Ca(2+)-free solution moderately reduced the adhesive strength with consequently less ultrastructural damage. Active Ca(2+)-deprivation further reduced the retinal adhesion, but may have induced damage as suggested by intracellular vacuolization. Hyperosmolarity and ischemic conditions had toxic effects on both the photoreceptors and RPE cells. In contrast, the use of a preheated Ca(2+)-free solution (34 degrees C) substantially reduced retinal adhesiveness under vitrectomy conditions and hence ultrastructural damage. CONCLUSIONS: Artificial retinal detachment causes substantial ultrastructural damage in eyes with physiological retinal adhesiveness if performed under vitrectomy conditions similar to surgery in humans. The use of a preheated Ca(2+)-free physiologic saline solution seems to be suitable to reduce retinal adhesion sufficiently, without causing significant cellular damage.

Adhesiveness↗
PubMed2005

Zinc uptake and storage: the role of fundus pigmentation.

BACKGROUND: Age-related macular degeneration (AMD) is associated with lower melanin pigmentation and is more prevalent among the elderly Caucasian population than among Africans. A correlation between light iris colour, fundus pigmentation and the incidence of AMD is reported. Moreover, melanin represents the main storage of zinc in the eye. Zinc enhances antioxidant capacity through its function as a cofactor of important enzymes or by influencing gene expression of regulatory elements in the eye. In this study, we investigated the uptake and storage of zinc in the human choroid/retinal pigment epithelium (RPE) complexes in dependence on the fundus pigmentation as judged by the iris colour. MATERIAL AND METHODS: Choroid/RPE complexes of blue and brown human eyes were used. Tissues without any substitution served as controls. Specimens from choroid/RPE complexes were incubated with 100 microM zinc chloride for 24 h. After incubation, pieces of the complexes were stored to investigate the uptake of zinc. The rest of the tissues were kept for 3 and 7 days in culture medium (DMEM) for storage examination. The concentration of zinc was measured by inductively coupled plasma mass spectrometry. RESULTS: After 24 h of zinc treatment the concentration of zinc in the choroid/RPE complexes of blue eyes was not significantly increased. The concentration of zinc in highly pigmented tissues (brown eyes) was increased by the factor 5.1 after 24 h and remained at high levels after 3 days (factor 4.4) and 7 days (factor 2.8). CONCLUSIONS: Zinc uptake in the choroid/RPE complex correlates to the iris colour. Alterations of the degree of iris pigmentation result in differences of zinc uptake and storage in the choroids. A potential protective role of zinc may be more prominent in dark- than in light-coloured eyes.

Adult↗