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Biomedical subjects

S Bopp

Publications and source records attributed to S Bopp.

At least 19 recordsLinked to original sources
PubMed2007

Treatment of central retinal vein occlusion by radial optic neurotomy in 107 cases.

BACKGROUND: To evaluate the potential role of radial optic neurotomy (RON), a new surgical technique has been recently proposed for treating central retinal vein occlusion (CRVO). It is hypothesized that CRVO constitutes a neurovascular compartment syndrome at the site of the lamina cribrosa, which can be alleviated by performing a radial incision at the nasal part of the optic nerve head, relaxing the cribriform plate and the adjacent sclera. METHODS: One hundred and seven patients were treated with RON for CRVO at five collaborating ophthalmologic centers. All patients were evaluated by a standardized protocol. For analysis of the angiographic and fundus findings, reference images were used. Intraoperative and postoperative complications were reviewed. RESULTS: On 55 right and 52 left eyes of 107 patients (55.6% male, 44.4% female) with a median age of 68 years (range 21-91 years), RON was performed. The median follow-up time was 6 months (range 1-24 months). The median preoperative visual acuity (VA) was 0.05 (logMAR 1.3), increasing to a median postoperative VA of 0.08 (logMAR 1.1). Patients with an interval of more than 90 days between RON and onset of CRVO showed no significant change in VA at the 6-month follow-up. Severe peripapillary swelling of the optic nerve head prior to RON resulted in an average increase of 4.2 lines in VA at the 6-month follow-up. Angiographic findings of shunt vessels were seen in 18/30 cases after 12 months and were accompanied by an average improvement of VA of six lines. Visual field tests showed various defects in 86.8% of all cases. In one patient an iatrogenic injury of the central retinal artery occurred (0.9%). CONCLUSION: Despite the potential risk of visual field defects, RON seems to be a quite safe procedure. The majority of patients showed rapid normalization of the morphologic fundus findings, with an improvement in VA uncommon for the natural history of CRVO. No significant change in VA was seen in patients with an interval of more than 90 days between the onset of CRVO and RON. A prospective study is warranted for further investigation.

Adult↗
PubMed2006

Verteporfin photodynamic therapy induced apoptosis in choroidal neovascular membranes.

AIM: To evaluate the impact of verteporfin photodynamic therapy (PDT) on the induction of apoptosis in choroidal neovascular membranes (CNV) secondary to age related macular degeneration. METHODS: Retrospective review of 22 surgically excised CNV. 12 of these patients had been treated with PDT 3-146 days previously. Apoptotic cells were detected with the TUNEL technique and compared to the expression of CD34 (endothelial cells, EC), CD105 (activated endothelial cells), Ki-67 (proliferation marker), and cytokeratin18 (retinal pigment epithelial cells, RPE). RESULTS: CNV excised 3 days after PDT were characterised both by collapsed and patent vessels. The EC displayed a statistical significant positive TUNEL reaction when compared to the remaining treated CNV (p < 0.001) and untreated CNV (P = 0.002). The proliferative activity was reduced. CNV excised 1-5 months after PDT displayed a patent vascularisation and high proliferative activity. All membranes either treated or untreated disclosed only sporadic TUNEL positive cells within the stroma and the RPE. CONCLUSIONS: Verteporfin PDT leads to selective and effective damage of EC within CNV. Both patent and occluded vessels were lined by apoptotic EC. This finding and the increased expression of proliferation marker at later time points suggest that revascularisation after PDT is caused by angiogenesis rather than recanalisation.

Aged↗
PubMed2003

Comparative in vivo analysis of the sealing ability of three endodontic sealers in post-prepared root canals.

AIM: To compare the sealing ability of the endodontic sealers AH Plus, Sealer 26 and Endofill in premolar teeth of dogs exposed to the oral cavity after post-preparation. METHODOLOGY: Forty teeth with two canals each underwent root canal cleaning and shaping. Before filling, the canals were randomly distributed into three groups according to the sealer to be used: Group 1 - AH Plus; Group 2 - Sealer 26; and Group 3 - Endofill (Dentsply, Indústria e Comércio Ltda.). Immediately after filling, the gutta percha and sealer were partially removed from the canals, leaving material only in the apical third of the root. The teeth were temporarily sealed with glass ionomer sealer for 72 h to ensure setting. The coronal seal was then removed and the canals were exposed to the oral cavity for 45 days. The animals were euthanased and their mandibles and maxillae were removed. After abundant irrigation with distilled water, the canals were dried and filled with India ink. The teeth were sealed again for 96 h before extraction. The roots of the extracted premolars were separated and stored in labelled test tubes. The roots were cleared and the extent of dye penetration was measured with a 20x stereoscopic magnifying lens. RESULTS: Statistical analysis revealed that there were significant differences between the sealers studied (P < 0.001). Means for the extent of dye penetration for AH Plus, Endofill and Sealer 26 were, respectively, 0.13, 2.27 and 3.08 mm. CONCLUSIONS: After 45 days exposure to the oral cavity, none of the sealers was capable of preventing leakage and coronal dye penetration. There were significant differences between the sealers studied, in terms of mean dye penetration.

Analysis of Variance↗
PubMed1998

The vascular component of proliferative vitreoretinopathy membranes: an immunohistochemical and ultrastructural study.

BACKGROUND: The basic cellular components of proliferative vitreoretinopathy (PVR) membranes are well studied. Endothelial cells have also been documented. The importance of the vascular element in PVR has received little attention, as vascular components are clinically inapparent. The aim of this study was to obtain a better characterization and quantification of occurrence of the vascular component. METHODS: Serial sections of surgically excised PVR membranes were examined with Lectin histochemistry (25 membranes with ulex europaeus agglutinin I [UEA I] and rhicinus communis agglutinin I [RCA I]), immunohistochemistry for von Willebrand factor (31 membranes), and electron microscopy. RESULTS: Vascular endothelial cells were identified by visualization of UEA I and RCA I binding sites or by marking for von Willebrand factor. A total of 28.6% of the PVR membranes showed a vascular component. Vascular components consisted mostly of capillary-sized vessels; larger vessels were rarely found. Ultrastructurally, most vascular elements were found to be capillaries of the nonfenestrated type. Membranes from eyes that underwent PVR surgery with silicone oil tamponade showed vascular components less frequently (18.5%) than did membranes from eyes without silicone oil (43.8%).

Endothelium, Vascular↗
PubMed1997

Peripheral visual field loss after vitreous surgery for macular holes.

BACKGROUND: Vitreous surgery for Idiopathic macular holes can result in both anatomic closure of the hole and visual improvement. In some patients even normal visual acuity is achieved. Postoperative visual field loss is a newly recognized complication. This prospective study evaluates the frequency and significance of scotomas after vitrectomy with gas tamponade for stage I-IV macular holes. METHODS: Over a period of 10 months, a consecutive series of 30 patients and 31 eyes with macular holes underwent pre- and postoperative automatic perimetry (Octopus 07, 70 degrees) and macular perimetry (Octopus M1, 24 degrees) to characterize the pattern of visual field defects after vitrectomy with gas tamponade. Success rates were evaluated and complications were analyzed. RESULTS: Anatomic success after one surgical procedure was achieved in 85% of cases, visual improvement in 58%. Some 70.1% of patients had peripheral scotomas postoperatively; some of these were highly symptomatic and others were detected by visual field testing only. The most consistently affected areas were the temporal and lower periphery of the visual field. The central visual field, however, was not disturbed. CONCLUSION: Visual field loss after otherwise successful surgery for macular holes is an unexpectedly frequent and serious complication. The authors discuss various factors that may contribute to the postoperative scotomas. From the localization of the scotomas it seems most likely that they are caused by the persistent pressure of the gas bubble on the peripheral retina. Further investigations are necessary to confirm this hypothesis, and ways must be found to avoid this complication in order to be able to proceed with this otherwise promising new indication group for vitreous surgery.

Aged↗
PubMed1995

Sequence polymorphisms in the apo(a) gene associated with specific levels of Lp(a) in plasma.

Most of the interindividual variations in plasma levels of lipoprotein(a) [Lp(a)] can be attributed to sequence differences linked to the apolipoprotein(a) [apo(a)] locus. Plasma levels of Lp(a) tend to be inversely related to the number of kringle 4 (K4)-encoding sequences in the apo(a) gene, but there are several exceptions to this general trend. Other aspects of the apo(a) gene, in addition to the number of K4 repeats, affect plasma levels of Lp(a). To identify sequences in the apo(a) gene that contribute to plasma Lp(a) levels, we characterized the relationship between a length polymorphism [(TTTTA)n] located 1.3 kb 5' of the first exon of the apo(a) gene, the number of K4 repeats in the gene, and the plasma levels of Lp(a). There was significant linkage disequilibrium between the number of TTTTA repeats and the number of K4 repeats. All of the apo(a) alleles with 11 TTTTA repeats contained fewer than 24 K4 repeats and were paradoxically associated with low plasma Lp(a) levels (< or = mg/dl). To determine whether this association was due to the effect of the 11 TTTTA copies on apo(a) gene transcription, we measured the ability of fragments containing 11 or eight TTTTA repeats to promote transcription when introduced into cultured human hepatocarcinoma cells. No difference was found in the transcriptional activity of the two fragments. The TTTTA repeat constitutes the first sequence polymorphism at the apo(a) locus, other than the number of K4 repeats, which is associated with plasma concentrations of Lp(a).

Alleles↗
PubMed1995

Ten allelic apolipoprotein[a] 5' flanking fragments exhibit comparable promoter activities in HepG2 cells.

Plasma levels of the atherogenic lipoprotein[a] represent a quantitative genetic trait that is primarily controlled by the polymorphic apolipoprotein[a] locus on chromosome 6q. The more than 1000-fold variation in lipoprotein[a] plasma levels is explained to a large extent by a remarkable size polymorphism of the apolipoprotein[a] gene which is translated into apolipoprotein[a] isoforms and by unidentified sequence variation in apo[a]. In a recent report, sequence variation in a 1.5 kb fragment from the 5' flanking region of the apolipoprotein[a] gene was associated with different promoter activities, which led to the suggestion that transcriptional control of the apolipoprotein[a] gene might contribute significantly to lipoprotein[a] plasma levels. We have used a reporter gene assay to compare the promoter activities of these 1.5 kb fragments which were cloned from ten well-characterized apolipoprotein[a] alleles. These ten allelic apolipoprotein[a] fragments revealed, despite the same sequence variation as previously reported, comparable and relatively weak promoter activities in HepG2 hepatocarcinoma cells. Promoter activity for the same fragment in non-liver cells and the identification of a liver cell-specific DNaseI hypersensitive site 3 kb upstream from the ATG start codon suggest that longer fragments must be used in order to analyze the transcriptional regulation of the apolipoprotein[a] gene.

Alleles↗
PubMed1995

[Endotamponade with silicon oil in severe proliferative retinopathy with attached retina].

Silicone oil as endotamponade in cases with attached retina is only indicated in a few very selected cases. These are cases with a high risk of intravitreal hemorrhage and a need for quick visual rehabilitation. We examined 23 patients, who had undergone pars plana vitrectomy and silicone oil filling. All patients were diabetics with proliferative retinopathy and recurrent intravitreal hemorrhage. In 14 cases it was the only eye; 11 eyes previously had a vitrectomy. We analyzed these cases for visual acuity, rubeosis, bleeding tendency, reproliferations, cataract development and glaucoma. The follow-up time was 32 months. In 22 of 23 eyes quick visual rehabilitation was achieved, and the patients had at least ambulatory vision within the first week. In one case poor visual acuity was due to exudative maculopathy. No relevant bleeding occurred. In 14 of 16 phacic patients we observed a cataract. Seven patients developed glaucoma, which was due to neovascularization in 5 cases. It was successfully treated in all cases and no visual loss occurred. In 5 cases we observed a peripheral traction retinal detachment, in one case a traction retinal detachment at the posterior pole. In selected cases silicone oil can prevent recurrent intravitreal hemorrhage, allowing rapid visual recovery. Considering the complications, the silicone oil should be removed as soon as possible.

Diabetic Retinopathy↗
PubMed1994

[Proliferative retinopathy in chronic myeloid leukemia].

BACKGROUND: In 50% of patients with acute and chronic myelocytic leukemia retinal alterations occur which are similar to those of nonproliferative diabetic retinopathy or hypertensive retinopathy. Retinal neovascularizations, however, are rarely seen and only found in patients with the chronic disease. PATIENTS AND METHODS: We report on the clinical course of three patients with advanced stage of proliferative retinopathy in CML. In two patients, the diagnosis of CML was established after ocular involvement. Therapy was planned according to the principles, which have proven effective in other vasoproliferative retinopathies. Eyes with neovascular changes were only treated by panretinal scatter photocoagulation of the avascular zones. In the cases with complications like vitreous hemorrhage and traction retinal detachment, vitreoretinal surgery was performed. RESULTS: Using this therapeutic principles in 4 of 6 eyes a visual acuity > 0.7 could be preserved. In three eyes impending macular involvement by traction retinal detachment was prevented. CONCLUSION: The therapeutic approach, which is valid for proliferative retinopathies of various etiology is also beneficial for ocular complications in CML.

Adult↗
PubMed1994

[Clinical heterogeneity of non-Hodgkin's lymphoma of the eye with extraocular manifestations].

Primary, ocular Non-Hodgkin lymphoma is a multicentric disease. The prognosis is mostly determined by involvement of the central nervous system and/or visceral organs. Since ocular symptoms often precede accompanying manifestations and since the eye is easily accessible to diagnostic measures, the ophthalmological diagnosis is essential for early detection and treatment of this complex disease, which has a poor prognosis. To illustrate the extraordinary heterogeneity of the clinical symptoms, four case reports have been selected which demonstrate various ocular symptoms and extraocular localizations. The ophthalmological variability ranges from typical uveitis to retinitis and vasculitis with varying symptoms during the progression of the disease. Completely different extraocular features were induced by long-standing, local infiltrates within basal ganglia, a diffuse infiltration of the brain leading to an acute increase in intracranial pressure, a peripheral tumour within the spinal channel or massive infiltrates of liver, lung and kidneys. Lack of pathognomonic features, high clinical variability and the limited value of imaging techniques and histopathological measures often lead to serious delays in diagnosis.

Aged↗
PubMed1994

The photoreceptor cells and retinal pigment epithelium of normal and diseased human retinas express different glycoconjugates.

The photoreceptor cells and retinal pigment epithelium (RPE) represent a highly differentiated functional unit that may be disrupted in a variety of retinal diseases. We studied the localization and distribution of carbohydrate residues in normal and pathologically altered human retinas using lectin histochemical techniques. Paraffin-embedded tissue sections were investigated for binding sites with six lectins: concanavalin A (Con A), wheat germ agglutinin (WGA), Ricinus communis agglutinin (RCA I), peanut agglutinin (PNA), soybean agglutinin (SBA), and Ulex europaeus agglutinin (UEA I). Lectin binding to both the photoreceptor segments and the RPE was observed in the normal retina with Con A, WGA, RCA I, and PNA, particularly to the distal outer segments and to the apical portion of RPE cells. Disturbance of the photoreceptor-RPE cell complex occurred in eyes with damaged outer retinal layers and those with retinal detachment. Photoreceptor cells with a varying degree of inner and outer segment degeneration revealed an overall decrease in lectin-binding sites as well as alterations in their cellular topography. Reactive and proliferating RPE, however, showed a markedly increased reaction intensity for Con A, WGA, RCA I, and PNA as well as additional binding sites for SBA in macrophage-like variants. The data are taken as evidence that in the normal retina, a characteristic location and distribution of lectin-binding sites as well as correspondences in certain cellular glycoproteins of both photoreceptor cells and the RPE are indicative of structural and functional integrity. Disturbance of the photoreceptor-RPE cell complex is accompanied by changes in the expression of lectin-binding sites on both cell types.

Aged↗
PubMed1993

Retinal lesions experimentally produced by intravitreal ultrasound.

Currently, vitreous surgical techniques combined with phakoemulsification are an established procedure for the removal of luxated natural lenses or dislocated lenticular material. This has proven to be a safe procedure, but occasionally retinal lesions have been inadvertently created. We describe the ophthalmoscopic and morphologic features of ultrasonically induced retinal lesions in rabbit eyes using a similar technique. The retina was treated directly using a conventional ultrasound tip for pars plana lensectomy (Fragmatome). Ophthalmoscopically slight lesions corresponded to an area of retinal whitening. More severe lesions showed a destruction of the inner retina and created a retinal break. Extensive effects also involved the choroid and led to a retinal defect with rupture of choroidal vessels and heavy bleeding into the vitreous cavity. Histologic evaluation showed that the acoustic energy primarily led to damage of the outer retina, later involving the inner retina and the choroid as well.

Animals↗
PubMed1992

Lectin binding pattern in human retinal pigment epithelium.

A comparative lectin histochemical study of human retinal pigment epithelium (RPE) was performed to investigate the lectin binding pattern of normal, reactive and proliferating RPE. Normal RPE with attached sensory retina was found to bind the lectins Con A, WGA, PNA and RCA I. Reactive and proliferating RPE in retinal detachment and in photocoagulation scars revealed the same lectin binding pattern although its cellular topography changed. RPE-macrophages showed an additional reaction with SBA. In periretinal membranes of human PVR the typical lectin binding pattern of Con A, WGA, PNA and RCA I was found in pigmented and in a subpopulation of non-pigmented cells, suggesting that these lectin-positive elements were of RPE-origin. Additionally, single pigmented cells positive for SBA were found indicating macrophage differentiation. Thus lectin histochemistry provides a tool for cytochemical identification of RPE and its morphologic variants by revealing a specific combination of sugar-binding sites.

Binding Sites↗
PubMed1992

Acute onset of rubeosis iridis after diabetic vitrectomy can indicate peripheral traction retinal detachment.

Acute onset or exacerbation of rubeosis iridis associated with peripheral retinal detachment after vitrectomy represents a rare but serious complication of advanced diabetic retinopathy that indicates a poor prognosis. The clinical features, surgical procedures, and anatomical and functional results for a series of 13 eyes presenting with this complication are reported. In addition to rubeosis iridis and peripheral retinal detachment, anterior hyaloidal fibrovascular proliferation (APH) was also present in 10 eyes. All eyes had undergone one or more previous vitrectomies for diabetic complications such as nonclearing vitreous hemorrhage and traction retinal detachment. Treatment modalities for iris neovascularization and peripheral retinal detachment included reattachment procedures with an encircling band, peripheral membrane peeling, and, if necessary, peripheral retinectomy. Peripheral coagulation therapy was performed in all eyes. Eight eyes received an intraocular silicone-oil tamponade. Early results (4 weeks post-surgery) showed regression or stabilization of rubeosis iridis in all eyes. Later results (mean, 9 months post-surgery) revealed nine eyes with stabilized anterior ocular neovascularization and reattachment of the retina. Four eyes were anatomic failures due to recurrent rubeosis iridis/AHP or traction retinal detachment, and three of them also developed ocular hypotony. None of the eyes has thus far been lost as a result of neovascular glaucoma or painful phthisis. Ambulatory vision was retained in ten eyes, but function was limited to a low level as a result of the underlying ischemic disease. Immediate reattachment surgery in combination with anterior/peripheral coagulation therapy was shown to be an effective measure for controlling iris neovascular activity in eyes afflicted with acute anterior ocular neovascularization.

Acute Disease↗
PubMed1992

Congenital grouped albinotic spots: a rare anomaly of the retinal pigment epithelium.

We describe the fundus findings of a 6-year-old girl with congenital grouped albinotic retinal pigment epithelial spots distributed over the fundus including the macular area. Apart from the fundus changes functional and electrophysiologic findings were normal, and the family history was uneventful. At follow-up 3 years later, no progression was noted.

Albinism, Ocular↗
PubMed1991

[Peripheral retinal streaks. Linear depigmentation of the peripheral retinal pigment epithelium].

An unusual peripheral depigmented streak lesion of the retina is described in three patients. This depigmented line is located in the equatorial region running parallel to the ora serrata and seems to result from a focal reduction or loss of pigmentation in the retinal pigment epithelium. Similar lesions have been reported as a symptom of the presumed ocular histoplasmosis syndrome (POHS) called linear streaks of the equator. As we did not find any additional symptoms of POHS in our patients, the aetiology of this peripheral depigmented streaks remains unclear.

Aged↗
PubMed1991

[Corneal Ascher ring. A ring-shaped stromal corneal opacity].

An unusual bilateral ring-shaped corneal opacity has been observed in two patients. Biomicroscopical characteristics are minute greyish dots which are distributed within the outer stromal layers forming an arcus lipoides-like circular band. Besides of a typical arcus senilis no other corneal anomalies can be found. Up to date only 4 patients with similar corneal opacities have been described. Etiology remains unclear and according to the author who has first described this symptom we propose to name this corneal anomaly "Ascher-Ringe".

Aged↗