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Biomedical subjects

A Kampik

Publications and source records attributed to A Kampik.

At least 145 records · Page 8Linked to original sources
PubMed1994

Growth hormone (GH), insulin-like growth factors (IGFs), and IGF-binding protein-3 (IGFBP-3) in a child with Proteus syndrome.

Proteus syndrome is a congenital hamartomatous disorder characterized by partial overgrowth involving all germ layers. A somatic mutation model has been proposed since familial cases are extremely rare. We report on a 3-year-old girl with typical manifestations of Proteus syndrome, including local, asymmetric hypertrophy of various parts of the body. Total body length was reduced. Serum levels of IGF-I and especially IGF-II and their major growth hormone dependent binding protein (IGFBP-3) were significantly reduced, although growth hormone secretion after a pharmacological stimulus was normal. In vitro studies of fibroblasts derived from hypertrophied tissue showed normal IGF-I production and somewhat reduced IGF-II and IGFBP-3 production as compared to normal human skin fibroblasts. Affinity cross-linking experiments showed that fibroblasts of the affect tissue in Proteus syndrome produced an unusual pattern of IGF bindings proteins containing large amounts of an IGFBP with high affinity to IGF-II. The data suggest that IGF production is generally disturbed in Proteus syndrome with imbalanced levels of specific IGFBP in affected tissue.

Adult↗
PubMed1994

[Pathogenesis and therapy of central serous retinopathy].

UNLABELLED: There is no consensus in the literature on the etiology and therapy of central serous retinopathy. We conducted a retrospective study to find out whether patients treated with argon laser coagulation (ALK) experienced long-term visual acuity improvement. We were also concerned to find whether choroidal perfusion was involved in the etiology. PATIENTS: In all, 28 patients (4 women/24 men) with RCS confirmed by angiography were analyzed. All patients were followed up from 1988 to 1992. Patients with chronic recurrent RCS were not considered. Angiography was performed to examine the type and localization of the leakage and also the choroidal perfusion. Patients who were treated with ALK were compared with patients who were not. RESULTS: Only 9 patients were treated with carefully directed ALK. Their mean visual acuity was 0.5 (STD 0.09) before therapy. After treatment the mean visual acuity was improved to an average of 0.8 (0.23). The follow-up time was up to 56 weeks. The patients without ALK had an initial visual acuity of 0.6 (0.21) which improved to 0.8 (0.22) during an observation period of 60 weeks. By the end of the study the visual acuity was the same in both groups. In 46% of all patients delayed choroidal perfusion was seen on angiography. CONCLUSION: There was no difference in visual acuity between patients treated with and without ALK. The angiographic examinations suggest general changes in choroidal perfusion in patients with RCS.

Adult↗
PubMed1994

[Risk of retinal detachment in pseudophakia and axial myopia].

The incidence of retinal detachment on axial myopic pseudophakic eyes after Nd:Yag laser capsulotomy or intraoperative complications varies in the literature. In this study we analysed the incidence of retinal detachment in 136 pseudophakic myopic eyes (axial length > or = 26.0 mm) with and without capsulotomy and after intraopertive complications. These results were compared with those published in the literature and those obtained in a control group of 136 pseudophakic eyes with an axial length of less than 26.0 mm. Both groups were followed up for 2 years following operations in 1989 and 1990. The incidence of retinal detachment in eyes with axial myopia > or = 26.0 mm was 3.6% (5/136), without capsulotomy 3.3% (3/90) and with capsulotomy 2.5% (1/40). Intraoperative defects of the posterior capsule occurred in 6 cases, and in 1 case retinal detachment (1/6) developed. No retinal detachment occurred in the control group. The risk of retinal detachment does not seem to be significantly higher after uncomplicated extracapsular cataract extraction in eyes with axial myopia than in myopic eyes in which cataract extraction has not been performed. The combination of capsulotomy and axial myopia does not seem to increase the risk of retinal detachment. However, intraoperative complications do increase the risk of retinal detachment. Retinal detachment is three times as likely to develop in pseudophakic myopic eyes as in eyes with normal axial length.

Adult↗
PubMed1994

Prognostic factors in vitreous surgery for proliferative diabetic retinopathy.

A total of 25 proliferative diabetic eyes of 24 patients scheduled for vitrectomy were examined. The overall preoperative visual acuity was below 0.1, corresponding to hand movement in most patients because of intravitreal hemorrhage. Hence, funduscopy was not possible. The following tests were performed in addition to standard clinical examination: Purkinje entoptic phenomenon, laser interferometry, perception of color flashes, and flicker-VEP using 1.8, 7.6, 15, and 30 Hz as stimulating frequencies. Only the flicker-VEP revealed results predicting reliably the functional visual outcome at 6 months after vitrectomy. Patients with a positive preoperative response to 15 or 30 Hz had a significantly (P < 0.05) better visual outcome at 6 months after vitrectomy (mean postoperative visual acuity 0.11; 95% confidence interval, 1/25-0.32) as compared with patients showing a positive preoperative VEP-response to only 1.8 and 7.6 Hz (mean postoperative visual acuity, hand movement; 95% confidence interval, light without projection--1/35). The flicker-VEP can give additional information about the integrity of the retina and the function of the optic nerve and can therefore help the surgeon to predict the functional result after vitrectomy.

Adult↗
PubMed1994

[Results of pars plana vitrectomy with intraocular SF-6 gas tamponade in complicated retinal detachment].

Vitrectomy following complicated retinal detachment (PVR, giant tears, persistent retinal detachments or redetachments) has become standard in ophthalmic surgery. Intraocular tamponade is performed with gas (e.g. SF-6) or silicone oil. We retrospectively analyzed our functional and anatomical results after vitrectomy with SF-6 gas tamponade in complicated cases of retinal detachment. Ninety-four severe retinal detachments in 85 patients were treated by vitrectomy using SF-6 gas tamponade in the period from July 1990 to June 1991. In 68% of eyes complete retinal reattachment was achieved with the use of SF-6 gas. Thirty-two per cent of the operated eyes developed retinal redetachment an average of 3.4 weeks after initial surgery; 27% of those eyes were treated again with the use of silicone oil. The success rate using vitrectomy with SF-6 gas ranged between 46% and 74%, depending on pathogenetic factors. The best results were obtained in patients receiving primary vitrectomy for complicated retinal detachment. It is concluded that SF-6 gas is a successful tool in the treatment of severe retinal detachment with primary vitrectomy. In cases of persistent or recurrent detachment of the retina the results are not equally good and these cases merit consideration of silicone oil tamponade, depending on the severity of the disease process. However, no definite preoperative criteria for the success of vitrectomy and gas tamponade were identified.

Follow-Up Studies↗
PubMed1993

[Calculating and development of refraction in theoretical intraocular lens implantation in early childhood].

BACKGROUND: For various reasons the implantation of an intraocular lens in very young children remains a controversial matter. Although an intraocular lens might solve the problems of aniseiconia and amblyopia better then other forms of correction, the growth of the eyeball remains a major problem for constant refraction. MATERIAL AND METHODS: Therefore we theoretically analysed the biometric data from small children with regard to the development of refraction in 29 children (40 eyes). RESULTS: These theoretic calculations demonstrate that with an aimed refraction of -2.0 diopters at the time of cataract-operation, refraction at an age of 10 years varies from -2.75 diopters to -32.0 diopters (mean -11.75 diopters). The calculated aniseiconia at the age of 10 varies between 1 and 76% (mean 11%). In analysing these biometric data according to the age of the children at the time of surgery it is evident, that refraction at an age of 10 years would be more within a normal range if the age at the time of operation was certainly above 12 month of age. CONCLUSIONS: According to this theoretical analysis implantation of an intraocular lens appears not to be meaningful at an age of less than 12 months at the time of operation. If lens implantation in older children is considered the further growth of the eyeball should be taken into account when calculating the power of an intraocular lens.

Anthropometry↗
PubMed1993

[Does combined pancreas-kidney transplantation modify diabetic retinopathy in type-1 diabetic patients?].

The study group consisted of 30 patients with a functioning pancreas graft of at least 12 months. Fifty-seven eyes were examined; 26 eyes from 15 patients with a non-functioning pancreas graft made up the control group. Three patients were in both groups because their graft was rejected after a 12-month period. The mean age in the study group was 37 years, the mean observation time 38 months. The mean duration of diabetes before transplantation was 24 years and all patients were on kidney dialysis. Retinal coagulation for diabetic retinopathy had previously been performed in 80.7% of the patients. The mean age (38 years), observation time (36 months), duration of diabetes before transplantation (24 years), and incidence of retinal coagulation (84.6%) were comparable in the control group. All patients had regular ophthalmological examinations every 6 to 12 months. This included best-corrected visual acuity, applanation tonometry, slit-lamp examination and dilated binocular funduscopy. Seven 30 degrees fundus pictures of the posterior pole were taken: The images were graded by comparing them with the ETDRS (Early Treatment Diabetic Retinopathy Study) Group standard photographs. The original Airlie House grading scale was changed because we did not take stereoscopic pictures. Evaluation and grading were done independently by two examiners. The retinopathy score was graded from 0 (no retinopathy) to 11 (no evaluation possible due to opaque media). Visual acuity remained stable in both the study and control groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Intercellular adhesion molecule-1 (ICAM-1) and leukocyte function-associated antigen-1 (LFA-1) expression in human epiretinal membranes.

Various histogenetically different cell types such as macrophages, retinal pigment epithelial cells, glial cells, and fibroblasts are involved in the formation of epiretinal membranes. In the development of such multicellular tissues, cellular adhesion molecules (CAMs) are necessary for cell migration, proliferation, and localization, and the transfer of information between the cells. We investigated the expression of the intercellular adhesion molecule 1 (ICAM-1) and the leukocyte function-associated antigen 1 (LFA-1) in frozen sections of epiretinal membranes in proliferative vitreoretinopathy (PVR), proliferative diabetic retinopathy (PDR), macular pucker, and recurrent membranes after intraocular silicone oil tamponade using the indirect immunoperoxidase method. ICAM-1 forms a receptor-ligand pair with LFA-1 and is involved in a number of significant cellular interactions, e.g. in providing dynamic position-specific information to guide lymphocyte and leukocyte localization in the immune response. ICAM-1 is a member of the immunoglobulin gene super-family of CAMs. LFA-1 is a member of the integrin family of cell membrane receptors. It mediates a wide range of lymphocyte, monocyte, natural killer cell, and granulocyte interactions with other cells in immunity and inflammation, and it is a receptor for ICAM-1. The LFA-1 interaction with its ligand ICAM-1 mediates not only cell adhesion but also signal transduction in immunologic and inflammatory cell responses. Basal ICAM-1 expression is normally low on nonhematopoietic cells, but it can be subject to an up-and-down regulation by various cytokines.(ABSTRACT TRUNCATED AT 250 WORDS)

Antigens, CD↗
PubMed1992

Problems and timing in the removal of silicone oil.

The risk associated with silicone oil removal after complex vitreoretinal surgery is unclear. Therefore, a cohort of 87 consecutive cases of silicone oil removal were analyzed. Eyes with attached retina before silicone oil removal with a follow-up of at least 5 months were included into the study. Forty-eight eyes had severe proliferative diabetic retinopathy; 39 eyes had complex proliferative vitreoretinopathy or giant retinal tears after trauma. Additional clinical features included the presence of a secondary cataract or secondary glaucoma in some eyes. The rate of postoperative complications was different in the two groups: 75% of proliferative diabetic retinopathy patients remained attached; of proliferative vitreoretinopathy patients, only 48.5% remained stable. Whereas success was independent of the duration of intraocular silicone oil tamponade in proliferative diabetic retinopathy, removal of silicone oil was more successful in cases of proliferative vitreoretinopathy in which there was a longer period of silicone oil tamponade. Complications occurring usually were severe and led to a loss of visual acuity. The removal of silicone oil from eyes with secondary glaucoma resulted in an improvement in 68% of patients. The rate of vitreoretinal complications after silicone oil removal, even in cases with a clinically stable-appearing retina, is rather high. Silicone oil removal therefore has to be considered a procedure posing new and ill-defined risks, especially if the indications for the use of silicone oil as an internal tamponade are rather strict. Exact criteria for the timing and safe removal of silicone oil in these complex vitreoretinal disorders still need to be defined.

Adult↗
PubMed1992

Experimental evaluation of in vitro stability of purified polydimethylsiloxanes (silicone oil) in viscosity ranges from 1000 to 5000 centistokes.

One of the main problems in the clinical use of silicone oil in vitreoretinal surgery is the instability of the material in terms of emulsification. Fine silicone oil droplets can cause a secondary glaucoma by blocking aqueous outflow. Intravitreally applicable silicone oils comprise an inhomogeneous group of materials, and the rate of emulsification depends on the physicochemical properties of the silicone oils. Clinically most frequently used silicone oils are highly purified polydimethylsiloxanes with a viscosity of 1000 centistokes (cs) to 5000 cs. Low-viscosity silicone oils are preferred by some surgeons because of easier surgical handling and easier removal out of the vitreous. The authors investigated highly purified polydimethylsiloxanes in viscosity ranges of 1000 cs, 2000 cs, 3000 cs, 4000 cs, and 5000 cs with regard to their in vitro stability to evaluate the optimal range of viscosity with acceptable material stability. The comparative stability tests were performed with 0.1% salt solutions of albumin, acidic alpha-1-glycoprotein, fibrin, fibrinogen, gamma globulins, and very-low-density lipoprotein as emulsifiers. Silicone oil at 5000 cs was in all cases distinctly more stable than the silicone oils with a viscosity up to 4000 cs. A positive correlation between the degree of viscosity and an increase of material stability was not found with all emulsifiers. When very-low-density lipoprotein, albumin, and fibrin served as detergents, a remarkable stability gain was achieved only at 5000 cs.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Proteins↗
PubMed1992

Proliferative activity and immunohistochemical cell differentiation in human epiretinal membranes.

Epiretinal membranes are a complex tissue mainly formed by the proliferation of retinal pigment epithelial cells, macrophages, glial cells, and fibroblasts. The proliferative contribution of these cells in regard of the formation of an epiretinal membrane is not yet clear. We determined the cellular proliferative activity by the use of the monoclonal antibody Ki-67 in 46 epiretinal membranes of proliferative vitreoretinopathy (PVR), PVR recurrences after intraocular silicone oil tamponade, proliferative diabetic retinopathy, and macular pucker. The proliferative activity of each membrane was indicated by the proliferative index (PI), which is the ratio of the actively proliferating Ki-67-positive cells and the total cell number in a cross-section of the membrane. The PI of each membrane was combined with the expression pattern of cell type associated antigens like cytokeratin for epithelial-like cells, KiM7 for macrophages, and glial fibrillary acidic protein for glial cells. Such a membrane typing revealed distinct interindividual differences, but no strict correlation with the underlying disease process. Our findings support the idea of an individual "fingerprint-like" membrane typing at the time of surgery combining the information about the antigen expression pattern of the participating cells and their functional proliferative state. Individual membrane typing for each patient might become clinically significant as soon as the dominating cells for tissue proliferation become key targets for specific pharmacological interventions.

Cell Differentiation↗
PubMed1992

Proliferative activity in epiretinal membranes. The use of the monoclonal antibody Ki-67 in proliferative vitreoretinal diseases.

Epiretinal membranes occur in a number of pathogenetically different diseases, such as proliferative vitreoretinopathy (PVR), proliferative diabetic retinopathy (PDR), macular pucker, and ischemic, inflammatory, and degenerative vitreoretinal disorders. The formation of epiretinal membranes is characterized by the proliferation of histogenetically different cell types. Knowledge of the proliferating potential of surgically excised epiretinal membrane tissue might be clinically relevant to determine which patients face a high risk of recurrences. The monoclonal antibody Ki-67 specifically stains a cell-cycle associated nuclear antigen that is only expressed by cells in the G1, S, and G2/M phases of the cell cycle. With this antibody, the actively proliferating growth fraction can be stained in frozen tissue samples of surgically removed epiretinal membranes by the indirect immunoperoxidase method. In this study, the monoclonal antibody Ki-67 was used to screen 37 epiretinal membranes in PVR, PDR, macular pucker, and in recurrences after intraocular silicone oil tamponade for the presence of actively proliferating cells. Additionally, the number of Ki-67 positive cells in a section of the membrane was quantitatively set in relation to the total cell number of this section. Thus a proliferative index (PI) was ascribed to each membrane as a decimal quotient. The proliferative indices can be graded into four subgroups for missing or very low (PI less than 0.1), low (PI 0.1-0.3), moderate (PI 0.3-0.6), and high (PI greater than 0.6) proliferative activities. High proliferative activities were found in 4 of 5 PVR membranes, in 9 of 14 PDR membranes, in 6 of 11 recurrent membranes after intraocular silicone oil tamponade, and in 2 of 6 macular pucker membranes.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Monoclonal↗
PubMed1991

Immunohistochemical localization of epidermal growth factor receptor in a human epiretinal membrane.

Cell growth in proliferative vitreoretinopathy (PVR) is activated by naturally occurring mitogenic substances; thus, growth factors seem to play an important role in PVR. Cell activation by growth factors requires the presence of specific cell-bound receptors by which the mitogenic signal is transmitted. Using the indirect immunoperoxidase method, we investigated frozen sections of 15 epiretinal membranes in PVR for the presence of epidermal growth factor receptor (EGFR), which is commonly utilized by epidermal growth factor (EGF) and transforming growth factor-alpha (TGF-alpha). This receptor could be localized only in one epiretinal membrane. The receptor-bearing cells stained positively for vimentin, cytokeratin, and macrophage marker Ki-M7, indicating that they most probably correspond to transformed macrophages. They stained negatively for desmin and glial fibrillary acidic protein. The cells were embedded in a fibronectin-positive intercellular matrix and were in an actively proliferating state as demonstrated by positive staining for the nuclear proliferation marker Ki-67. We propose that EGFR might be expressed only in certain as yet undefined stages of PVR.

Autoantigens↗
PubMed1991

Long-term follow-up of diabetic retinopathy for up to 71 months after combined renal and pancreatic transplantation.

This study reports the course of diabetic retinopathy in 25 patients (41 eyes, 9 one-eyed patients) who had undergone successful renal and pancreatic transplantation. The mean duration of follow-up was 38 months (range, 15-71 months). Visual acuity improved in 13 eyes (32%), remained stable in 19 (46%) and deteriorated in 9 (22%); only 2 of the latter 9 eyes (5%) sustained severe visual loss according to the definition of the Diabetic Retinopathy Study Group. The frequency and severity of vitreous hemorrhage improved in 19 eyes (46%), remained unchanged in 18 (44%) and worsened in 4 (10%). In comparison with other modes of treatment such as intensified conventional insulin therapy and artificial insulin-delivery systems, the combined renal and pancreatic transplantation seems to have advantages concerning the course of proliferative diabetic retinopathy.

Adult↗
PubMed1991

Emulsification of silicone oils with specific physicochemical characteristics.

To determine the exact role of various factors in silicone-oil emulsification, we investigated eight different silicone oils with specific physicochemical characteristics in terms of their rate of emulsification. The silicone oils were defined by viscosity, volatility, amount of low-molecular components, electrical resistivity, degree of purification and chemical composition. The viscosities differed between the ranges of 1000 and 10,000 cs. The silicone oils included purified polydimethylsiloxane (PDMS), hydroxyl-enriched PDMS and trimethylsiloxy-terminated polydiphenylsiloxane (PDPS). As emulsifiers we used 0.1% solutions of fibrinogen, fibrin, gamma globulins, acidic alpha-1-glycoprotein, very-low-density lipoprotein and serum dissolved in sterile, distilled water as well as in balanced salt solution. The group of low-viscosity silicone oils (1000 cs) was least stable. The greatest difference in stability was found among purified PDMS, having viscosities between 1000 and 5000 cs. The most stable oil was purified PDMS, whose emulsification rate was almost identical at 5000 and 10,000 cs. High contents of hydroxyl end groups enhanced silicone-oil emulsification to a greater extent than did phenyl side groups. The strongest emulsifiers were fibrinogen, fibrin and serum, followed by gamma globulins, very-low-density lipoprotein and acidic alpha-1-glycoprotein. Balanced salt solution accelerated silicone oil emulsification in all cases. For reduction of emulsification in vivo, purified PDMS of high viscosity should be used. Biologically active emulsifiers found in hemorrhages or inflammatory situations might be lowered in vivo by hemostasis and sufficient postoperative anti-inflammatory therapy.

Electrolytes↗
PubMed1991

[Clinical use and results of trans-scleral Nd-YAG cyclophotocoagulation in therapy-refractory glaucoma].

We report on our results of transscleral Nd-YAG-cyclophotocoagulation on 27 eyes with refractory glaucoma. Cyclophotocoagulation was performed with similar parameters according to our findings of morphological investigation in normal human donor eyes. 9 eyes had hemorrhagic glaucoma, 10 eyes had secondary glaucoma after intraocular silicone oil tamponade because of proliferative diabetic retinopathy or because of complicated retinal detachment with proliferative vitreoretinopathy. None of the patients in this group had silicone oil in the anterior chamber, silicone oil emulsification and only one eye had rubeosis iridis. The third group of 8 eyes had glaucoma with aniridia, post-traumatic or postinflammatory glaucoma, glaucoma after extraction of a congenital cataract and one eye with an absolute painful pseudoexfoliation glaucoma. The effects were applied coaxially through the conjunctiva at 1 to 1.5 mm distance from the limbus. The energy was between 3.8 and 4.2 Joules, the exposure time was 10 ms. The focus of the laser beam was placed 3.6 mm posteriorly with a focus adjustment of 9 at the LASAG Microruptur 2. The mean postoperative observation period was 7.5 months. Among the group of hemorrhagic glaucomas the intraocular pressure could in 78% be lowered below 22 mmHg, in 60% among the secondary glaucomas after intraocular silicone oil application and in 50% among the heterogenous third group. In eyes with preceding cyclocryocoagulation 82% fulfilled this criterion. The intraocular pressure stayed stable after 4 weeks at a mean level of 40% below the preoperative values. In all cases the intraocular pressure was at least lowered by 14 mmHg. Vision was reduced in three eyes by the underlying disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗