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Biomedical subjects

K U Bartz-Schmidt

Publications and source records attributed to K U Bartz-Schmidt.

At least 91 records · Page 5Linked to original sources
PubMed1998

External beam radiation in patients suffering from exudative age-related macular degeneration. A matched-pairs study and 1-year clinical follow-up.

BACKGROUND: The aim of this prospective study was to ascertain whether external beam irradiation is effective in patients with subretinal neovascularization (SRN) due to age-related macular degeneration (AMD). METHODS: All patients had subfoveal SRN due to AMD as verified by fluoresceinangiography. Two hundred and eighty-seven patient-eyes were treated by external beam irradiation (total dose of 16 Gy in 2-Gy fractions, 5 times a week) from January 1996. The analysis was restricted to those 73 patients with a minimum follow-up of 11 months. Eighteen patients with subfoveal SRN who refused treatment served as control group (CG). 18 patients of the treatment group (TG) were matched for visual acuity, refraction and extent of SRN. The statistical analysis was performed with the unpaired t-test. RESULTS: The mean age of the CG was 73.9 years (range 66.9-81.3 years) and of the TG 75.6 years (range: 65.7-80.6 years). The median follow-up was 13.5 months (range 11.9-18.4 months) in the CG and 12.9 months (range 11-13.9 months) in the TG. The initial visual acuity (VA) was 20/80 in both groups. After 7 months the follow-up revealed median VA of 20/400 in the CG and 20/160 in the TG (P=0.0335). The final median VA was 20/400 in both groups, with a range from 20/40 to 20/1000 in the CG and from 20/63 to 20/500 in the TG (P=0.2433). The SRN doubled in size during this time in both groups. CONCLUSION: These results suggest that external beam irradiation applied in 2-Gy fractions 5 times a week slows down the visual loss in exudative AMD for a short time. Nevertheless, the patients' reading vision could not be saved in the long term.

Aged↗
PubMed1998

Failure of sorivudine therapy in progressive outer retinal necrosis caused by varicella zoster virus.

BACKGROUND: We report on the case of a 23-year-old female who presented with ocular signs of progressive outer retinal necrosis (PORN) syndrome and who failed to respond to acyclovir, ganciclovir, foscarnet and oral sorivudine. METHODS: The patient was treated with the antiviral drugs acyclovir, ganciclovir, foscarnet and oral sorivudine. RESULTS: The patient failed to respond to a combination of antiviral drugs. Unfortunately, progression of the retintis occurred, which led to blindness. CONCLUSION: Despite new drugs, the prognosis of PORN is poor and recurrence is common.

AIDS-Related Opportunistic Infections↗
PubMed1998

Intravitreal daunomycin induces multidrug resistance in proliferative vitreoretinopathy.

PURPOSE: Adjuvant intravitreal daunomycin is frequently used for the management of proliferative vitreoretinopathy (PVR). In this study the authors examined whether daunomycin could induce multidrug resistance (MDR), mediated by the mdr-1 gene product P-glycoprotein, in the cells responsible for reproliferation in vivo and in human retinal pigment epithelial (RPE) cells in vitro. METHODS: Expression of P-glycoprotein was examined by immunohistochemistry in surgically removed epiretinal membranes. The cellular source of P-glycoprotein was examined by colabeling for cytokeratin, glial fibrillary acidic protein, and the macrophage marker EBM-11. P-glycoprotein expression by cultured RPE cells was assessed by reverse transcription-polymerase chain reaction and immunoblot analysis. Daunomycin toxicity was quantified by crystal violet assay. RESULTS: P-glycoprotein expression was detected in 10 of 10 patients pre-exposed to intravitreal daunomycin. In contrast, epiretinal membranes from only 2 of 13 patients never exposed to daunomycin showed faint P-glycoprotein expression. P-glycoprotein expression was strong within 8 months after daunomycin treatment and faded thereafter. Colocalization studies demonstrated predominant expression of P-glycoprotein by RPE cells. Pre-exposure of cultured human RPE cells to subtoxic concentrations of daunomycin induced resistance to daunomycin that was sensitive to the MDR inhibitor, verapamil. Induction of the MDR phenotype in RPE cells by daunomycin was associated with a minor increase in the mdr-1 mRNA level but a prominent increase in P-glycoprotein expression, thus suggesting a primarily translational mechanism of MDR development in human RPE cells. CONCLUSIONS: Intravitreal daunomycin induced P-glycoprotein expression in PVR. Reproliferation in daunomycin-pretreated patients probably necessitates cotreatment with daunomycin and inhibitors of multidrug resistance such as verapamil or administration of antiproliferative drugs such as 5-fluorouracil, which act in a MDR-independent fashion.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1997

Branch retinal artery occlusion by diathermy of a persistent hyaloid artery.

PURPOSE: To report branch retinal artery occlusion caused by diathermy of a persistent hyaloid artery. METHODS: Case report. A 21-year-old woman with unilateral tractional retinal detachment caused by contraction of the persistent primary vitreous underwent vitrectomy with endocoagulation of the primary hyaloid artery. RESULTS: Postoperatively, the patient had opacification of the neurosensory retina in the area of the inferotemporal branch retinal artery accompanied by a corresponding visual field defect. CONCLUSIONS: Diathermy of a persistent hyaloid artery may be complicated by the occlusion of a branch retinal artery. In similar cases, atypical branches of retinal arteries must be considered. Dissection of the anomaly from the posterior lens capsule should be performed without coagulation or perhaps endoscopically if visualization is obscured by a Mittendorf dot.

Adult↗
PubMed1997

[Vitrectomy in treatment of eyes with complicated uveitis].

BACKGROUND: Vitrectomy serves as an important treatment modality in uveitis, removing inflamed vitreous body and eliminating secondary complications. The aim of our retrospective study was to evaluate the value of vitrectomy in the treatment of complications in uveitis. PATIENTS AND METHOD: We included 50 eyes of 50 patients suffering from chronic uveitis, which underwent vitrectomy surgery during the period of 1990 to 1993. The study only included patients who had vitrectomy for uveitis for the first time. Indications leading to surgery were density of optic media, retinal detachment, cyclitic or preretinal membranes. The mean follow-up was 455 (range 48-1420) days. RESULTS: Vitrectomy was performed at a mean delay of 452 days after initial presentation. The mean visual acuity at the time of surgery was 0.05. The best visual acuity postoperatively was measured at a mean time of 118 days after vitrectomy. Overall, at the last control, eyes with preoperative retinal detachment presented a much worse final functional result (visual acuity of 0.02) than eyes without detachment (visual acuity of 0.5). Ten eyes resulted in hypotonia after surgery (7 eyes with persisting hypotonia). Most frequent complications in the postoperative course were macular pucker (11 eyes), secondary glaucoma (10 eyes), macular edema (6 eyes) and retinal detachment (6 eyes). Fifty percent of all complications occurred within the first 3 months following surgery. CONCLUSION: Vitrectomy leads to a permanent increase in visual acuity through the treatment of complications, on the condition that a stable retinal situation was present preoperatively.

Adult↗
PubMed1997

Descemet's membrane as membranous support in RPE/IPE transplantation.

PURPOSE: The correct orientation of retinal pigment epithelium (RPE) cells is necessary for the integrity and proper function of the retina. For transplantation of RPE/iris pigment epithelium (IPE) grafts to the subretinal space in age-related macular degeneration, this cellular orientation is most effectively provided by a membranous support. The goal of this study was to establish an autologous or homologous membrane as a substratum for the growth of RPE/IPE. METHODS: Porcine and bovine RPE and IPE were placed in primary culture on a dissected sheet (5 x 5 mm) of autologous porcine and bovine Descemet's membrane in slide chambers and grown to confluence. RESULTS: RPE and IPE cells cultured on Descemet's membrane form an intact monolayer. Light and electron microscopy showed the formation of both an intact monolayer and microvilli in both cell types. CONCLUSION: Since the slow host-graft rejection appears to play an important role in the failure of RPE transplantation in the subretinal space, it is critical to be able to transplant autologous materials. The techniques presented here establish a novel means to culture RPE or IPE cells on autologous Descemet's membrane where they form a "cell monolayer patch," consisting of a fragment of Descemet's membrane with cultured RPE or IPE, which can be easily manipulated and transplanted, using an established glass pipette method.

Animals↗
PubMed1997

The artificial iris diaphragm for vitreoretinal silicone oil surgery.

BACKGROUND: Silicone keratopathy frequently develops as a complication of silicone oil tamponade in the management of severe trauma in eyes with partial or complete aniridia. We therefore designed an "open" artificial iris diaphragm to prevent silicone oil-endothelial contact. In hypotony, where insufficient circulation of aqueous allows silicone in the anterior chamber despite an open diaphragm, a new solution became necessary. The "closed" artificial diaphragm was developed. METHODS: In this retrospective study, two consecutive series of artificial iris diaphragms were compared. Forty-four patients received either an open type (20 eyes) or a closed type (24 eyes) and were observed for 409 +/- 421 days (range, 32-1912). All eyes were aphakic, normotonous, and had a traumatic, compromised iris diaphragm or were aphakic and hypotonic as a result of injury, proliferative vitreoretinopathy, proliferative diabetic retinopathy, or uveitis, with an intact natural iris diaphragm. RESULTS: Silicone oil was retained behind the open diaphragm throughout the observation period in 40% of the eyes. Major long-term complications were hypotony and fibrous overgrowth. Silicone was retained behind the closed diaphragm in 50% of the eyes. CONCLUSION: Because proliferative vitreoretinopathy is active for months and multiple surgical interventions become necessary to avoid phthisis in eyes with highly pathologic changes, longstanding or permanent silicone tamponade is used. The artificial diaphragm prevents silicone-corneal contact in approximately 50% of aphakic eyes for at least 1 year.

Adolescent↗
PubMed1997

Plasminogen in proliferative vitreoretinal disorders.

OBJECTIVE: Intravitreal fibrin formation is a frequent observation after vitrectomy performed for a variety of vitreoretinal disorders including proliferative vitreoretinopathy (PVR), proliferative diabetic retinopathy (PDR), and endophthalmitis. Plasminogen activators (PA) have been used for the management of this postoperative complication. This approach requires the presence of plasminogen, the substrate for PA mediated fibrinolysis, in the vitreal cavity. METHODS: Quantification of plasminogen in the vitreous of 60 patients with PVR, PDR, and macular pucker was performed by streptokinase mediated activation using a chromogenic substrate. The presence of immunoreactive plasminogen was confirmed by immunoblot analysis of vitreal proteins and immunocytochemistry of surgically removed epiretinal membranes. RESULTS: Plasminogen levels were dramatically increased in the vitreous of PVR and PDR patients compared with macular pucker patients and normal controls. Staining for plasminogen in epiretinal membranes was confined to the extracellular matrix. Predominant staining of perivascular areas in PDR specimens indicated that breakdown of the blood-retinal barrier is an important source of intravitreal plasminogen in that condition. CONCLUSION: Plasminogen may play a role in traction membrane formation in PVR and PDR. Our biochemical analysis of presurgical vitreous indicates that there may be abundant substrate for PA mediated fibrinolysis in the vitreous cavity after vitrectomy.

Eye Diseases↗
PubMed1996

The triple flash electroretinogram and its significance in macular diseases. B-wave recovery as a diagnostic tool.

PURPOSE: The purpose of this study was to evaluate recovery data for the b-wave of the electroretinogram (ERG) elicited using multiple flash stimulation with increasing stimulus intervals in normal controls and in patients with macular diseases. The results will describe effects of age and macular disease and define indexes characterizing the recovery process. METHODS: Scotopic Ganzfeld flash ERGs were elicited using interstimulus intervals of 140, 280, and 560 ms. Relative b-waves were calculated as the ratio b140 ms/b560 ms and b280 ms/b560 ms, respectively. Responses obtained in 134 eyes of 134 normal controls served as reference data. Fifty-four patients with different macular diseases were also examined and their data compared to the reference data. RESULTS: Relative b-wave amplitudes correlated with interstimulus interval and with flash luminance, but not with age. All patients had a normal ERG when recorded following the standard of clinical electroretinography. A sigmoidal model was suggested, providing three indexes characterizing the b-wave recovery process. Relative b-waves and recovery indexes varied in age-related macular degeneration, central serous retinopathy, vitelliform macular degeneration, Stargardt's disease, and pattern dystrophy. CONCLUSION: The triple flash ERG reflects energy-yielding and -utilizing mechanisms. It proved to be more sensitive in detecting functional lesions in macular diseases than the standardized explorating procedure. The b-wave recovery model allows differentiation between two independent mechanisms contributing to the b-wave recovery process. One or more of the three characterizing indexes are affected in different macular diseases.

Adolescent↗
PubMed1996

The cumulative normalised rim/disc area ratio curve.

BACKGROUND: The assessment of the cup of the optic disc depends, among other criteria, on the disc area. A small cup in a small optic disc can indicate an advanced glaucomatous lesion, while on the other hand a large cup in a large optic disc can be normal. Therefore, a cumulative normalised rim/disc area ratio curve could help to distinguish between glaucomatous and normal optic cups. The aim of our study was to calculate normalised rim/disc area ratio curve. METHODS: Heidelberg Retina Tomograph examinations of the optic nerve head of 100 randomly selected eyes of 100 normal subjects were evaluated. We calculated the disc area-adjusted normalised rim/disc area ratio in sectors of 10 degrees. The 95th, 90th and 50th percentiles of each of the 36 sectors were displayed in descending order. RESULTS: In relation to the normal percentile curves, it is possible to display an individual normalised rim/disc area ratio curve. We obtained such curves for a normal optic disc, optic nerve heads with moderate and advanced lesions and a small optic disc with glaucomatous damage. CONCLUSION: We present a new display mode for the results of Heidelberg Retina Tomograph optic nerve head examination, which may be helpful for easy and reliable assessment of the local, diffuse and combined components of glaucomatous optic nerve head damage depending on optic disc size.

Adult↗
PubMed1996

Chronic basidiomycetous endophthalmitis after extracapsular cataract extraction and intraocular lens implantation.

BACKGROUND: Basidiomycetes are known as rare pathogens for meningitis, sinusitis, pneumonia, ulcerative lesions of the hard palate and onychomycosis. To our knowledge, no filamentous basidiomycete has been reported from a case of fungal endophthalmitis. PATIENT: We report on a 67-year-old man with delayed-onset endophthalmitis caused by an opportunistic basidiomycete. Tissue obtained during vitrectomy was cultured and examined by light and transmission electron microscopy. After enucleation the eye was examined by light microscopy. CONCLUSION: The patient had endophthalmitis from a sterile hyphomycete, harboured in remnants of lens capsule and a granuloma on the ciliary body. It was recognized as a Holobasidiomycete on the basis of its dolipore structure with perforated pore cap, seen with transmission electron microscopy. Species identification was not possible because fruiting bodies were absent. The patient failed to respond to intravitreal and systemic amphotericin B and systemic itraconazole. The eye was enucleated. This case demonstrates that filamentous basidiomycetes can cause endophthalmitis when inoculated during cataract extraction.

Aged↗
PubMed1996

Prognostic factors associated with the visual outcome after vitrectomy for endophthalmitis.

BACKGROUND: Functional results following vitrectomy with intraocular and systemic antibiotic treatment for endophthalmitis are influenced by numerous factors. METHODS: A retrospective study of 65 cases of endophthalmitis treated between October 1988 and May 1994 at the Department of Ophthalmology, University of Cologne, Germany was conducted. All eyes underwent pars plana vitrectomy and intraocular and systemic antibiotic treatment. RESULTS: Vision of 20/400 or better could be obtained in 66% of eyes following extracapsular cataract extraction and intraocular lens implantation (ECCE + IOL), in 62% after severe eye injury, in 36% of eyes after intraocular surgery for other reasons than cataract extraction with lens implantation and in 33% of patients with endogenous endophthalmitis. Vision of 20/50 or better could be achieved in 41% of eyes following ECCE + IOL and additional systemic steroid treatment. In 22% of cases primary silicone endotamponade was performed; 57% of these eyes obtained visual acuity of 20/400 or better. Fifteen patients (23%) suffered diabetes mellitus; 20/400 vision or better could be achieved in 73% of these eyes. Visual acuity of hand movements or better before vitrectomy was associated with 20/400 vision or better in 69% of cases, whereas ambulatory vision could be attained in only 33% of patients with visual acuity of worse than hand movements at the initial presentation. Visual acuity of less than 20/400 was found in all eyes with haemolytic streptococcal infections. CONCLUSION: Prompt treatment of endophthalmitis is crucial. Additional treatment using systemic steroids and, if necessary, silicone oil can improve the functional outcome in some cases.

Adult↗
PubMed1996

[Risk factors for retinal redetachment by proliferative vitreoretinopathy after episcleral surgery for pseudophakic retinal detachment].

BACKGROUND: Conventional buckling procedures in pseudophakic eyes are more often than in phakic eyes complicated by proliferative vitreoretinopathy (PVR). PATIENTS: The records of 68 patients (68 eyes) suffering from pseudophakic retina detachment between January 1988 to March 1993 were evaluated. We analysed the frequency of PVR-redetachment and possible risk-factors. RESULTS: Thirteen eyes (19%) developed PVR-redetachment after external surgery. Within this group we were not able to find a retinal break before or during surgery in 70% of patients (9 eyes), compared to 25% of patients in the group without PVR complication. CONCLUSIONS: Uncertain visualisation of the retinal break prior to and during external surgery along with persistent retinal detachment represent risk factors for PVR. Also, extended indentation and cryotherapy during frustrane hole localisation is likely to reduce absorption of subretinal fluid and increase blood-ocular-breakdown. Both factors are known to raise the risk of PVR. Whether or not these severe disadvantages of "blind buckling" can be relieved by primary vitrectomy is subject of future investigations.

Adult↗
PubMed1996

[Effects of fluorescein and indocyanine green angiography on subsequent dark adaptation and the electroretinogram].

BACKGROUND: In clinical practice the electroretinogram (ERG) usually should not be recorded immediately after conventional fluorescein angiography (FLA), because of the bleaching effects of strong light exposure on the course of dark adaptation and on the ERG. Currently it is not known, if indocyaningreen (ICG) angiography using the Heidelberg Retina Angiograph (HRA) has similar effects on the outer retina and if therefore the ERG should also not be recorded after ICG angiography. METHODS: Eight patients with different retinal diseases were examined. After 5 minutes of light adaptation to 160 cd/m2, Ganzfeld ERGs were repeatedly recorded using DTL electrodes during a 30 minutes dark period with a flash luminance of 0.1 cds/.m2. After this dark adaptation period a standardized ERG was recorded according to the ISCEV recommendations. This procedure was followed either by ICG angiography using the HRA or by conventional fluorescein angiography using the Canon CF 60 fundus camera. Within an interval of 5 minutes the above mentioned ERG procedure was repeated. RESULTS: ICG angiography using the HRA did neither affect the course of dark adaptation as measured by increasing b-wave amplitudes during the 30 minutes dark adaptation period, nor the values for each response of the Ganzfeld standard ERG. FLA did neither affect b-wave responses to dim stimuli, nor to stronger stimuli in the scotopic range. However, the course of dark adaptation was significantly prolonged after FLA. The maximum b-wave was not affected. CONCLUSIONS: ICG angiography using the HRA could be performed prior to the recording of the ERG, without any effect on the ERG. In contrast conventional FLA must be performed after ERG recordings, in order not to alter the electrophysiological responses.

Adult↗
PubMed1996

[Pathogenesis of complicated cataract in herpetic kerato-uveitis].

BACKGROUND: Keratitis, retinitis and secondary cataract are well known complications of ocular herpes simplex infection. We report on a case of herpetic keratouveitis and cataract. Acute and inflammatory pathogenesis of cataract formation resemble a phacoanaphylactic reaction. CASE REPORT: A 15-year-old girl with recurrent herpes keratitis was referred for acute spontaneous cataract formation accompanied by iridocyclitis and hypotony. Visual acuity was decreased from 0.4 to light projection. During cataract extraction the anterior chamber was tabbed for immunological analysis. The thickened anterior lens capsule was examined by light microscopy. We found a significant local synthesis of herpes antibodies in the aqueous. Histologically the lens capsule depicted a defect and a granulomatous inflammatory infiltrate towards the basal membrane material. The specimen was not suitable to judge on eventual additional phacoanaphylaxis. After cataract extraction and systemic acyclovir and corticosteroids the keratouveitis subsided. Visual acuity improved to 0.4, but was limited by the disciform corneal scar. CONCLUSION: The granulomatous response towards lens capsule shown here, resembles the granulomatous reaction towards Descemet's membrane in advanced herpetic corneal ulcer. We speculate on the pathogenesis of the lens capsule defect as a, so far unknown, herpes-associated autoimmun response against the basal membrane material of the lens. The acuteness of cataract formation may be a consequence of contact of aqueous with lens fibres. Additional phacoanaphylaxis combined with secondary glaucoma is possible.

Acyclovir↗
PubMed1996

[Effect of the contour line on cup surface using the Heidelberg Retina Tomograph].

BACKGROUND: Significance of topometric follow-up examinations of the optic nerve head in glaucomatous eyes depends on the reproducibility of the calculated parameters. Since the definition of the standard reference plane in software version 1.11 of the Heidelberg Retina Tomograph has been changed, intrapapillary parameters depend directly on the position of the contourline in the sector between -10 degrees to -4 degrees, and therefore on the observer variability to determine the disc border. We evaluated intra- and interobserver variability and present a simple approach to increase reproducibility. METHOD: The disc border of 4 glaucomatous eyes, 3 ocular hypertensive eyes and 3 eyes of healthy subjects were traced by two observers, 5 times using the free draw mode and 5 times by the addition of contourline circles. RESULTS: We found a median variability of the mean disc radius in sector -10 degrees to -4 degrees of 51 microns, which defines the position of the standard reference plane, resulting in a median variability of the position of the standard reference plane of 33 microns which caused a variability of 81 microns2 of the cup area. Addition of contourline circles smoothing the final contourline along the border of the optic disc resulted in a decrease of the coefficient of variation of the standard reference plane of 3.76% (6.76% vs. 3.0%), of the cup area of 2.34% (3.87% vs. 1.53%) and of the rim volume of 3.41% (9.75% vs. 6.34%). CONCLUSION: The calculation of the cup area using software version 1.11 of the Heidelberg Retina Tomograph depends on observer variability. The addition of contourline circles to define the final contourline along the disc border increases reproducibility. However, in follow-up of topometric examinations of the optic nerve head the software supported transfer mode should be used. Comparing topometric data of an individual optic disc in follow-up suppose the same definition of the contourline. Therefore, topometric data evaluated using software version 1.10 or earlier needs to be recalculated.

Adolescent↗