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Biomedical subjects

S Bopp

Publications and source records attributed to S Bopp.

31 records · Page 2Linked to original sources
PubMed1991

[Fluorescein angiography findings after retinotomy and retinectomy].

Drainage-retinotomies and relaxing retinectomies are helpful techniques in extreme vitreoretinal surgery. They have become established as a surgical instrument, but their possible pathophysiologic effects on the retina, pigment epithelium and choroid have not been investigated as yet. 30 Patients with retinotomies or retinectomies after vitrectomy with silicone oil filling for advanced proliferative vitreoretinopathy were studied angiographically. Fluorescein angiographic findings revealed 1. a predominant effect of endophotocoagulation in the area of the retinotomy/retinectomy with occlusion of the choriocapillaris and hyperpigmentation and window effects of the retinal pigment epithelium, but sometimes there was a localized traction effect with retinal and choroidal folds, 2. that retinal perfusion is unaffected in untreated and coagulated areas without evidence for a breakdown of the blood-retina-barrier or retinal ischemia, 3. an intact blood-retinal-barrier in areas of uncovered retinal pigment epithelium, 4. no evidence for significant reproliferations in the areas of retinotomies and retinectomies, 5. choroidal neovascular membranes which may occur postoperatively at the retinotomy site probably as a complication for intraoperative injury of Bruch's membrane, 6. a cystoid macular edema, an optic atrophy, pigment-fallout, depigmented tracks and choroidal folds as unspecific findings post retinal detachment surgery. The angiographic data support the clinical impression, that retinotomies and retinectomies performed in otherwise untreatable cases cause no significant damage in the attached retina.

Drainage↗
PubMed1991

[Retinal lesions after transvitreal use of ultrasound].

Removal of a dislocated natural lens into the vitreous cavity is now performed using vitreous surgery techniques combined with intravitreal phacoemulsification via the pars plana. In contrast to the earlier external surgical approach to luxated lenses, postoperative complications, particularly retinal detachment, are rare. However, retinal damage may occur when ultrasound is used at therapeutic intensities. We therefore examined ultrasound-induced retinal lesions produced in rabbit eyes by treating the retina directly with ultrasound using the type of tip conventionally used for pars plana lensectomy (Fragmatom). Histological evaluation showed that acoustic energy at low intensities led primarily to damage of photoreceptor cell outer and inner segments, which correlated with a discrete pigment reaction visible on ophthalmoscopy. More severe lesions were seen in destruction of the inner retina and resulted in retinal blanching or caused a small retinal break. High energy led to a full-thickness retinal defect with rupture of choroidal vessels and heavy bleeding into the vitreous cavity. Within these lesions the retinal pigment epithelium and Bruch's membrane were also disturbed. Our ophthalmoscopical and histological findings indicate that the mechanism of ultrasound-induced chorio-retinal lesions is not exclusively thermal in nature and differs from other coagulation modalities.

Animals↗
PubMed1991

[Pars plana capsule resection for therapy of ocular hypotension syndrome caused by capsule shrinkage with ciliary body detachment].

A rare complication of extracapsular cataract extraction is hypotony due to capsular shrinkage, with consequent ciliary body detachment. A classic hypotony syndrome with progressive loss of visual acuity was observed in two patients, one with extracapsular aphakia and one with extracapsular pseudophakia. Each presented with a fibrotic, shrunken capsular bag and a secondary cataract. As the contraction forces appeared to derive predominantly from the periphery of a circumferentially fibrotic capsular bag, the lens capsule was operatively removed. A pars plana approach was used to access the equatorial capsular ring and visualize the ciliary body processes. The intraocular lens appeared to be stable and remained in situ. Postoperative elevation of intraocular pressure occurred, with improvement of hypotony symptoms, especially in the fundus. Visual acuity also improved, but was limited due to secondary cystoid edema.

Adult↗
PubMed1990

[Results after retinotomy and retinectomy in the treatment of complicated retinal detachment].

Of 241 cases operated with pars-plana vitrectomy and silicone oil filling for complicated retinal detachment we performed retinotomies for drainage of subretinal fluid or removal of subretinal strands in 48 cases (20%) and retinectomies for relief of traction in 80 cases (33%). We found no negative influence of these retinotomies and retinectomies on the anatomic or functional outcome in our major indication groups--PVR, PDR and perforating injury. With increasing size of the retinectomy the anatomic success rate fell from 100% in cases with a 90 degrees retinectomy to 76% with a retinectomy larger than 270 degrees. In 21 out of 80 cases traction relief was insufficient so that we had to enlarge the retinectomy. 17 of these 21 cases could then be attached permanently.

Diabetic Retinopathy↗
PubMed1990

[Lectin histochemical studies of retinal pigment epithelium in retinal detachment].

The retinal pigment epithelium (RPE) exhibits a broad spectrum of morphological changes under pathological conditions. Since RPE cells cannot be immunocytochemically characterized with certainty, lectin histochemical investigations were performed to study the lectin binding pattern of different morphological RPE variants in human globes. Normal RPE with attached retinas was compared to reactive changes in RPE following retinal detachment. Lectin binding sites were visualized by a modified PAP technique performed on paraffin-embedded tissue sections. Eight lectins of different sugar affinity (Con A, WGA, PNA, RCA 1, SBA, UEA 1, DBA, LPA) were tested for binding sites on the RPE. Both normal and reactively changed RPE possess receptors for Con A, WGA, PNA, and RCA 1. Modifications in the lectin binding pattern occurred simultaneously with the morphological changes within the RPE cells. RPE cells which form a monolayer on Bruch's membrane mainly have lectin binding sites in their apical portions. Proliferating and migrating RPE cells, especially RPE macrophages, which have withdrawn from the basal cell layer were found to contain lectin binding sites dispersed over the entire cytoplasm. RPE macrophages exhibited additional binding sites for the lectin SBA. These results indicate that RPE cell variants can be designated by means of their specific combination of lectin binding sites for Con A WGA, PNA, and RCA 1 not found on other cell types in the retina.

Humans↗
PubMed1990

[Lectin histochemical studies of retinal pigment epithelium following photocoagulation].

Lectins are histochemical probes for specific carbohydrate residues found in cell membranes and the cytoplasm. Lectin binding sites were determined in normal and morphologically altered retinal pigment epithelium (RPE) in photocoagulation scars using a modified PAP method. Tissue sections of human bulbi obtained during enucleation for various reasons were incubated with eight lectins of different sugar affinity: ConA, WGA, PNA, RCA I, SBA, UEA I, DBA, LPA. The comparative study of normal and reactive migrating and proliferating RPE revealed lectin binding sites for Con A, WGA, PNA and RCA I. Differences in the lectin binding pattern of various morphological cell types occurred within the intracellular topographical distribution and density of lectin binding sites. SBA, UEA I, DBA and LPA are not found to react with the RPE. These results indicate that lectin histochemistry allows cytochemical identification of normal and reactive RPE, which shows positive staining with Con A, WGA, PNA and RCA I not found in other cell types of retinal origin.

Histocytochemistry↗
PubMed1989

[No disorder of arachidonic acid-induced thrombocyte aggregation in familial exudative vitreoretinopathy].

Six patients, members of a family with familial exudative vitreoretinopathy (FEVR), were studied to verify whether the disease was associated with a suspected platelet aggregation defect. No hemostaseologic defect was found in either the affected or healthy members of the family; in particular, there were no grounds for suspecting any disturbance of arachidonic acid-induced platelet aggregation.

Adult↗
PubMed1989

[Canthaxanthin retinopathy and macular pucker--clinical picture and ultrastructural findings of macular pucker].

Canthaxanthine retinopathy is a crystalline retinopathy that follow oral ingestion of canthaxanthine-containing drugs. We describe the clinical course of a patient with canthaxanthine retinopathy and preexisting idiopathic macular pucker over a period of 2.5 years. Light microscopic investigation of the macular pucker revealed a fibrocellular membrane containing granular, birefringent material and vacuoles within the cells of the membrane resulting from canthaxanthine deposits in the epiretinal membrane. Long-term follow-up shows a slight, but significant, reduction of the retinal crystals.

Aged↗
PubMed1989

[Canthaxanthin retinopathy and macular pucker].

Canthaxanthine retinopathy is a crystalline retinopathy following oral ingestion of canthaxanthine-containing drugs. We describe the clinical course of a patient with canthaxanthine retinopathy and a preexisting idiopathic macular pucker. The ultrastructural findings of the macular pucker removed by vitreoretinal surgery are demonstrated. Granular material and lipid-like droplets, not usual for a macular pucker, are the major findings in this membrane. There is evidence that the granular material consists of canthaxanthine deposits, phagozytized by the cells of the epiretinal membrane.

Aged↗
PubMed1989

[Cellular lectin binding sites in the human retinal pigment epithelium and photoreceptors--method of lectin histochemistry and results with peroxidase marked lectins in paraffin sections].

Lectins are sugar-binding proteins or glycoproteins which bind to specifically complementary sugar residues found in cell membranes and the cytoplasm. Lectin-binding sites are determined by histochemical methods. Cellular lectin-binding sites change with morphological and functional alterations of the cell, and the determination of lectin receptors can be used to identify specific cell types in histological sections. Lectin-binding sites of the human retinal pigment epithelium (RPE) and photoreceptor cells under normal and pathological conditions have not been examined. Lectin-binding sites of normal retinal pigment epithelium and photo-receptor cells obtained from enucleated human bulbi were identified by a modified PAP method. Eight lectins differing in their sugar affinity (Con A, WGA, PNA, RCA I, SBA, UEA, DBA, LPA) were used to investigate a wide range of glycoconjugate specificity. Normal RPE have receptors for the lectins Con A, WGA, PNA and RCA I, mostly localized in the apical portions of the cells. Binding sites for these lectins are also found on photoreceptor cells, but with different binding characteristics. Photoreceptor cells bind additional lectins (UEA, SBA, DBA), which are not found on the RPE.

Humans↗
PubMed1988

[Secondary pigmented macular pucker].

The clinical course and histologic findings in a case of macular pucker with secondary pigmentation are described. The macular pucker occurred following argon laser coagulation of a peripheral hole and consisted of elements of the inner limiting membrane, an extracellular matrix of collagen fibrils, and retinal pigment epithelial cells with varying degrees of differentiation. No retinal glial cells were found. The pigment epithelial cells had presumably migrated through the peripheral retinal hole and settled on the retinal surface.

Female↗
PubMed1981

[Animal experiments on the nephrotoxicity, pharmacokinetics and therapeutic efficacy of dibekacin].

Nephrotoxicity, pharmacokinetics, and therapeutic efficacy of 3',4'-dideoxykanamycin (dibekacin), a semisynthetic aminoglycoside, were evaluated in rats. As with other aminoglycosides, therapy with dibekacin led to an increased urinary cell and malic-dehydrogenase excretion. The lowest dose resulting in an increased urinary cell excretion was 2.5 mg/kg/d. Serum levels of dibekacin after i.m. injection of 5 mg/kg were similar to those of other aminoglycosides. The kidneys accumulated high amounts of dibekacin, and eliminated it with a half-life of about 7 days. After repetitive dosing a distinct tendency to accumulation (highest renal concentration: 330 microgram/g) could be detected. Experimental chemotherapy of the chronic estrogen induced pyelonephritis revealed that dibekacin and sisomicin fed to significant reductions of renal bacterial counts at a dosage of 2 x 5 mg/kg/d for 7 days. A dosage of 2 x 2.5 mg/kg/d diminished the effectiveness of dibekacin distinctly, that of sisomicin only slightly.

Animals↗