Biomedical subjects
Publications and source records attributed to A Kampik.
An 8-year-old boy presented with a white pupillary reflex. This clinical picture suggested a diagnosis of retinoblastoma or Coats' disease. Ultrasonography did not reveal the characteristic signs often seen in retinoblastoma. However, diagnostic vitrectomy and subsequent enucleation confirmed the diagnosis 'retinoblastoma'.
The question of the long-term risks and benefits of silicone oil removal after complex vitreoretinal surgery involving the use of silicone oil has not yet been answered. A consecutive series of 50 eyes from which silicone oil had been removed were therefore analyzed in a retrospective study. In all cases the retina was completely attached and seemed to be stabilized before silicone oil removal. The reasons for the original surgery were severe proliferative diabetic retinopathy (PDR) in 20 cases and proliferative vitreoretinopathy (PVR) in 30, in 2 of which PVR developed after perforating injuries. Silicone oil was removed because the retina was clinically stable and completely attached, and in some cases cataract or glaucoma was present. The complication rate after silicone oil removal in these situations varied widely in dependence on the form of disease. After PDR stable conditions were achieved in 70% of cases after silicone oil removal. After PVR with retinal detachment the situation remained stable in only 50%. The most frequent complication was retinal redetachment because of recurrent PVR, accounting for 80% of all failures. The success rate with silicone oil removal after PDR in this study was independent of the duration of tamponade, which had lasted for about 1 year in most cases. Following PVR, silicone oil removal seems to be more safer after long-term tamponade (22 months) than after a shorter duration (12 months). Secondary glaucoma during silicone oil tamponade could be influenced positively in 70% of all cases by silicone oil removal. Because of the relatively high rate of complications after silicone oil removal, especially in PVR, the indications for removal must be carefully considered.
Epiretinal membranes are a fibrocellular tissue whose cellular components are macrophages, glial cells, retinal pigment epithelial cells and fibroblasts. In our immunohistochemical study on epiretinal membranes in proliferative vitreoretinopathy (PVR), proliferative diabetic retinopathy, macular pucker, uveitis and after intraocular silicone oil tamponade we analyzed the cellular growth patterns of these histogenetically different cell types on serial sections of paraffin-embedded and frozen material. In addition, the topographic distribution of fibronectin was analyzed and the localization of the epidermal growth factor receptor, which is the coreceptor for the transforming growth factor alpha, was examined by staining procedures. We used antibodies against macrophages (Ki-M7), cytokeratin, vimentin, desmin, glial fibrillary acidic protein and against the proliferation antigen Ki-67. The different cell systems often showed cell-type-specific growth patterns causing an "organoid" structure of the epiretinal membranes. Macrophages predominated in membranes of eyes affected by uveitis and after intraocular silicone oil tamponade. The coexistence of macrophages and other cell types within the same area might be explained by intercellular regulatory mechanisms. Fibronectin, which has functions that are important for cell adhesion, migration, proliferation and differentiation, was topographically localized mainly in areas of denser cell populations and within the walls of newly formed capillaries in diabetic membranes. There was no correlation with specific cell types, however. Among the cellular receptors necessary for signal transduction of mitogenic substances, we localized the coreceptor for the epidermal growth factor and the transforming growth factor alpha among actively proliferating macrophages in a PVR membrane.(ABSTRACT TRUNCATED AT 250 WORDS)
Between 1960 and 1987 29 patients underwent surgery at the Munich University Eye Hospital for benign and malignant tumors of the lacrimal gland. Fifteen tumors were classified as pleomorphic adenomas (three of them with malignant transformation), nine as adenoid cystic carcinomas, two as adenocarcinomas, two as oxyphilic adenomas, and one as oxyphilic adenocarcinoma. The clinico-pathologic correlation of these tumors is described. All age groups were involved in both benign and malignant epithelial gland tumors. A fast growing lesion with bone destruction of the lacrimal fossa in association with pain was found to be highly suspicious of a malignant epithelial tumor. Prior to surgery, inflammatory lesions and lymphomas should be ruled out by clinical history, examination, diagnostic imaging techniques, and, occasionally, by a short course of oral corticosteroids. A diagnostic biopsy prior to tumor excision and a transfrontal surgical approach via craniotomy has a negative impact on the prognosis. Thus it is mandatory to remove epithelial lacrimal gland tumors completely at the time of the initial surgical procedure. Craniotomies facilitate recurrences of lacrimal gland tumors by infiltration into the central nervous system. Lateral orbitotomies using the Krönlein technique are the best surgical approach for successful removal of these unusual tumors.
Silicone oil injection in conjunction with pars plana vitrectomy was carried out by five surgeons in 415 consecutive patients using the same surgical equipment, the same surgical techniques and the same highly purified silicone oil (viscosity, 5000 mPa.s). Indications for silicone oil injection after vitrectomy included advanced stages of proliferative vitreoretinopathy following rhegmatogenous retinal detachment (49%), severe proliferative diabetic retinopathy (38%), and proliferative vitreoretinopathy following retinal detachment due to ocular trauma (13%). Postoperative complications were noted in a 6- to 30-month follow-up period. Cataractous changes of varying degree were seen in all phakic eyes. Silicone oil entered the anterior chamber in 6% of all phakic and pseudophakic eyes. Subretinal silicone oil was noted in 4%. Other complications associated with the use of intravitreal silicone oil included biomicroscopically visible silicone oil emulsification (0.7%), keratopathy (5.5%), glaucoma (6%), closure of the inferior iridectomy (6%), and reproliferation of epiretinal and subretinal fibrous membranes (40%). We anticipate that the physico-chemical characteristics of the highly purified silicone oil (viscosity, 5000 mPa.s) and the routine performance of an inferior iridectomy in all aphakic eyes had a positive impact on the low incidence of silicone-oil-related complications such as emulsification, keratopathy and secondary glaucoma.
Case reports of two patients who developed a sudden hypotony with visual loss after an uneventful extracapsular cataract-extraction with posterior chamber lens implantation. There is evidence for the reason to be a contraction of the posterior capsule. This may lead to a traction at the ciliary body and a ciliochoroidal detachment. The rapid improvement of vision and intraocular pressure after Nd-YAG-Laser capsulotomy supports the postulated theory of this rarely discussed complication of intraocular lens implantation after extracapsular cataract-extraction. In this situation we recommend a capsulotomy in due time.
Macrophages and macrophage-like cells have been reported as cellular components of epiretinal and vitreous membranes. The origin and function of these versatile cells in the membranes are not fully understood. In the present study we used monoclonal antibodies reacting with macrophages, HLA-DR and monocytes (OKM5) to investigate cells in 52 specimens of various human epiretinal and vitreous membranes collected by vitrectomy. The results show that more than 80% of all membranes are positive for macrophage and HLA-DR antigen. HLA-DR is considered to be expressed by the macrophages. Cells reacting with antimonocyte (OKM5) are seen sporadically only in proliferative diabetic retinopathy. These results are discussed with respect to the possible origin of the macrophages and their important role in the development and formation of epiretinal and vitreal membranes.
In this study we evaluated the impact of preoperative factors on the choice of intraocular tamponades (balanced salt solution and gas or silicone oil) and postsurgical visual function in cases of vitrectomy for proliferative diabetic retinopathy. We studied 150 consecutive vitrectomies for proliferative diabetic retinopathy, which were carried out from October 1987 to February 1989. The extent of central or peripheral traction and retinal detachment were found to have a major influence on the choice of intraocular tamponades. Different types of diabetes, renal failure, and the time interval since the last vitreous hemorrhage showed no influence on the choice of intraocular tamponades. Visual acuity was improved after vitrectomy in the group with silicone oil tamponade, as well as in the control group with BSS or gas tamponade. Patients receiving silicone oil had more advanced stages of proliferative diabetic retinopathy and therefore more complicated postsurgical courses. Silicone oil is more likely to be avoided in cases without retinal detachment, where the risk of further vitreous hemorrhage is felt to be low and in cases with complete panretinal photocoagulation. The present study supports the therapeutic value of complete panretinal photocoagulation for proliferative diabetic retinopathy--even in cases where the proliferative retinopathy progresses and a vitrectomy is needed. It is demonstrated that many patients requiring vitrectomy did not receive sufficient photocoagulation earlier.
The stability of intraocularly applied silicone oils plays an important role in their biocompatibility. The clinically used silicone oils are not a unique group of materials. There are important differences regarding viscosity and the amount of low molecular and ionic components. A sign of bioinstability of silicone oils is silicone oil emulsification. According to clinical experience and experimental studies, less viscous silicone oils seem to emulsify earlier then more viscous oils. Therefore, we investigated three highly purified polydimethylsiloxanes with defined physicochemical characteristics and viscosities of 1,000 cs, 5,000 cs and 10,000 cs for their in vitro stability. As detergents, we used fibrin, fibrinogen, gammaglobulins, acidic alpha-1-glycoprotein, very-low-density lipoprotein (VLDL), and serum. The oil with a viscosity of 1000 cs was the most unstable silicone oil whereas the oils of 5,000 cs and 10,000 cs reacted similarly. The most effective detergents were fibrin, fibrinogen and serum-causing emulsification for all silicone oils investigated whereas gamma-globulins, acidic alpha-1-glycoprotein and VLDL only emulsified the less viscous oil of 1,000 cs. Our results show the importance of viscosity for the stability of silicone oils and the effect of biologically potential detergents.
A total of 42 cases (42 eyes) with silicone oil in the anterior chamber after pars plana vitrectomy (PPV) and after silicone oil injection into the vitreous cavity (SIV) were analyzed. The main complications caused by silicone oil were corneal endothelial cell damage and secondary glaucoma. Specular microscopy showed decreased cell density, apparent pleomorphism of endothelial cells, and increased corneal thickness. In some cases, edematous and necrotic endothelial cells were found. The characteristic optical artifacts resulting from silicone oil coming into contact with the endothelium, such as a bright reflex, reversed pattern of illumination, and interference fringes, were also observed. There was a definite correlation between elevated intraocular pressure (IOP) and the presence of silicone oil in the anterior chamber; the IOP dropped significantly on removal of the oil. The treatment and prevention of conditions involving silicone oil in the anterior chamber are briefly discussed.
In five children aged between 8 and 14, suffering from chronic recurrent uveitis of undetermined etiology, pars plana vitrectomy was performed in order to halt progression of the disease. Postoperatively there was a clear improvement in vision in all five patients, and in the follow-up period of 5 to 26 months there were no further recurrences of uveitis in the eyes which had been treated. These observations support the assumption that vitrectomy has a favorable effect not only in adults but also in children with therapy-resistant uveitis.
The success rate of pancreas transplantation allows us to study in more detail the potential beneficial effects of normoglycemia on secondary complications in diabetes mellitus. We report a prospective follow-up (mean 26 mo) of metabolic control, neuropathy, retinopathy, and peripheral microcirculation in 31 patients with type I (insulin-dependent) diabetes (mean age 33 +/- 1 yr; mean duration of diabetes 21 +/- 1 yr) after combined kidney and segmental pancreas grafting. All patients had normal HbA1 levels. Glucose tolerance (GT), insulin, C-peptide, and glucagon were normal in 22 patients, and impaired oral GT with reduced insulin secretory capacity was seen in 9 patients. During follow-up, there was no deterioration of GT and insulin release. Vascular risk factors, e.g., hypertension, cholesterol, and triglycerides, decreased after grafting. Autonomic neuropathy improved clinically, and R-R variation increased significantly in 3 of 18 patients. Peripheral neuropathy improved clinically in 46% of patients and did not deteriorate in the others. Motor nerve conduction velocity increased greater than 20% in 8, less than 20% in 12, and was unchanged in 8 of 28 recipients. Most of the patients (n = 30) had pretransplant laser treatment of their advanced retinopathy. Posttransplant visual acuity improved at least more than one line in 56%, stabilized in 32%, and deteriorated in 12% of patients. Patients with functioning grafts for greater than 1 yr had no further deterioration of visual acuity. Vitreous hemorrhage frequency and severity dropped markedly from pretransplant (from 69 to 24%) 10 mo after grafting. Retinal morphology remained stable in all eyes except two.(ABSTRACT TRUNCATED AT 250 WORDS)
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Epiretinal and vitreous membranes of different etiology, e.g., in diabetic retinopathy, following retinal detachment, trauma or inflammatory processes, show a similar morphology. The exact composition of the extracellular matrix and the pathogenesis of these membranes remain uncertain. The presence of collagens, type I-IV, laminin, and fibronectin can be shown by means of immunofluorescence with affinity-purified antibodies. Collagen type V was revealed by SDS-polyacrylamide-gel electrophoresis. These proteins of the extracellular matrix have diverse properties and functions in the membranes, as is discussed. Despite great similarities in morphology, there are some differences in the matrix, seemingly dependent upon the etiology of the membrane.
The orbital teratoma is a rare congenital neoplasm. It develops from ectopic pluripotential germinal cells. In none of the cases so far described in the literature were there any signs of malignancy. The clinical appearance of the tumor is very typical; it can be diagnosed by means of ultrasound and CT scan, as shown in the present paper. Fewer than 20% of all published cases of congenital orbital teratoma were treated by methods aimed at preserving the ocular bulb. The reason why so many cases were treated by exenteration of the entire orbit was the fear of malignancy which seemed to derive from the rapid growth of the tumor. However, not a single confirmed case of malignant orbital teratoma has been described in the literature. Hence an attempt should be made to perform a local excision of the tumor without sacrificing the ocular bulb. There is then a chance that some vision will be preserved and that development of the bony structures of the orbit will be improved.
Complications during the intraocular use of silicone oil can be caused by two factors: first, mechanical interaction with the surrounding tissue and, second, the physiochemical properties of the oil itself. The properties of 14 oils of various origins in clinical use were investigated: 12 of the 14 oils contained various amounts of low-molecular-weight components (cyclosiloxanes and molecules with a molecular weight of less than 2,400), which are able to diffuse into the surrounding tissue and may incite toxic or inflammatory reactions. Some of the samples had a ten-fold lower volume resistivity than others, an indicator of the presence of ionic impurities, such as catalyst remnants, which may also be responsible for adverse reactions.
Silicone oil with a higher specific gravity than that of intraocular fluid or polydimethylsiloxane may have special indications in vitreoretinal surgery. Trifluorsiloxane is such a substance, and therefore its biological compatibility was investigated in rabbit eyes. It was found that this substance was clinically well tolerated within the observation time of up to 6 months, even if there was some neovascularisation from the inferior limbus. Histologically both an inflammatory response and tissue impregnation were more pronounced than with normal polydimethylsiloxane.
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