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Biomedical subjects

K Heimann

Publications and source records attributed to K Heimann.

At least 91 records · Page 5Linked to original sources
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

[Contraction of extracellular matrix by transdifferentiated retinal pigment epithelial cells, inducers and inhibitors].

Transdifferentiated retinal pigment epithelial cells (RPE) display enhanced contractile potentials and have been implicated in the development of tractional retinal detachment. This study determines the activity of contraction-promoting factors, examines some involved mechanisms and evaluates inhibitors. Using an in vitro contraction assay, we demonstrated that collagen matrix contraction by transdifferentiated RPE cells is effectively stimulated by serum, platelet-derived growth factor and insulin-like growth factor-1. Endothelin-1 and transforming growth factor-beta 1 and -beta 2 have a more discrete or marginal effect. Tractional forces promoted by these peptides are completely protein synthesis dependent. Contraction stimulated by serum is only partly dependent on de novo protein synthesis, suggesting different active factors and/or pathways. Staurosporine, a broad-spectrum kinase inhibitor, effectively inhibited collagen matrix contraction by transdifferentiated RPE cells regardless of the promoter.

Collagen↗
PubMed1996

A standardized classification of ocular trauma.

BACKGROUND: No internationally standardized classification of ocular trauma terminology has existed previously. Despite a growing interest in eye injuries, the absence of a common language continues to impede both clinical care and research. METHODS: A classification has been developed initially based on the authors' extensive personal experience. It then has undergone repeated reviews over a 3-year period by international ophthalmic audiences, incorporating suggestions from respondents in 13 countries and selected ocular trauma experts. RESULTS: By always using the entire globe as the tissue of reference, the new classification is unambiguous, consistent, and simple. It provides definitions for the commonly used eye trauma terms within the framework of a comprehensive system. CONCLUSION: The new classification has been endorse by the Board of Directors of the International Society of Ocular Trauma, the United States Eye Injury Registry, the Hungarian Eye Injury Registry, the Vitreous Society, the Retina Society, and the American Academy of Ophthalmology. It can be reasonable expected that the system eventually will become the standardized international language of ocular trauma. The authors urge ophthalmologists to begin using this terminology in both clinical practice and research.

Eye Injuries↗
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

Primary vitrectomy for pseudophakic retinal detachment.

AIM/BACKGROUND: Viewing the peripheral retina is the major problem in the repair of pseudophakic retinal detachments. Conventional buckling procedures in pseudophakic eyes are complicated by persistent retinal (re-) detachment and proliferative vitreoretinopathy (PVR) more often than in phakic eyes. METHODS: Primary vitrectomy was performed in 33 consecutive cases for pseudophakic retinal detachment with the help of liquid perfluorocarbons and a wide angle viewing system, following a standardised procedure. All eyes have passed the 12 month follow up examination. RESULTS: The primary reattachment rate was 94%. PVR was observed in one case (3%). Seventy nine per cent (26 eyes) regained vision of 20/50 or better, with a median visual acuity of 20/30. The most frequent complication was transient glaucoma during the early postoperative period in 48% (16 eyes) requiring carboanhydrase inhibitors. CONCLUSION: The main advantage of primary vitrectomy over conventional buckling seems to be the better intraoperative sight to the most peripheral retinal holes, controlled removal of vitreous traction, and focused endolaser coagulation. This may explain the low rate of PVR after primary vitrectomy. Also, visual results tended to be better compared with conventional surgical techniques possibly because of removed vitreous opacities, and because of a superior retinal reattachment rate as well as the reduced rate of PVR.

Adult↗
PubMed1996

Clinical efficacy of haemorheological treatment using plasma exchange, selective adsorption and membrane differential filtration in maculopathy, retinal vein occlusion and uveal effusion syndrome.

The aim of the study was to test the clinical efficacy of haemorheological treatment with extracorporeal techniques in ocular diseases. We treated patients suffering from maculopathies of different origin: age-related (AMD, n = 17), uveitis-associated (n = 14) and myopia-associated maculopathy (n = 5). We also treated patients with uveal effusion syndrome (n = 3) and central retinal vein occlusion (n = 4) resistant to haemodilution or steroid therapy. The treatment consisted of plasma exchange, selective adsorption with a tryptophan-polyvinylalcohol adsorber and membrane differential filtration. Maculopathy patients underwent two treatments while the other patients received between 1 and 7 treatments. Pulsatile ocular blood flow was measured in 10 patients before and after therapy. The main parameter for evaluating clinical outcome was the change in visual acuity. Severe side-effects did not occur. The rheological parameters including plasma viscosity, whole blood viscosity and erythrocyte aggregation were statistically significantly lowered. Of 36 patients suffering from maculopathy, 25 showed an improvement of at least 1 line of visual acuity after therapy, 7/17 patients in AMD, 6/14 in uveitis and 0/5 in myopia improved 3 lines or more. All patients suffering from retinal vein occlusion improved at least 1 line and two showed an improvement of 3 lines or more. In uveal effusion syndrome, an improvement of 3 lines or more was reached in all patients. Plasma exchange, selective adsorption and membrane differential filtration are effective rheological treatment approaches to improving visual acuity in patients suffering from maculopathy except myopia-associated maculopathy. Efficacy in patients suffering from central retinal vein occlusion and uveal effusion syndrome was proven, even when the patients were resistant to previous haemodilution or steroid therapy. We conclude that a rheological approach should be considered before invasive methods such as laser coagulation, radiation therapy or surgery are applied.

Hemofiltration↗
PubMed1996

Apoptotic cell death in proliferative vitreoretinopathy.

Apoptosis is a selective event of physiological cell deletion that plays a crucial role in the development of numerous tissues, including the retina. In this paper we report the occurrence of apoptosis in epiretinal membranes derived from patients with proliferative vitreoretinopathy (PVR). Detection of apoptosis was performed by an in situ DNA-end labeling technique using terminal transferase-mediated deoxyuridine triphosphate (dUTP) incorporation. Apoptotic nuclei exhibiting chromatin condensation and fragmentation were also identified by acridine orange fluorescence. Apoptosis was detected in varying numbers of cells. The typical appearance of apoptotic nuclei, including nuclear chromatin condensation, was detected scattered inhomogeneously throughout the epiretinal membranes, in clusters, or even in single cells. Induction of apoptosis in human retinal pigment epithelial (RPE) cells by daunomycin could be demonstrated by in situ DNA end labeling and by quantitative determination of cytoplasmatic histone-associated DNA fragments using a photometric enzyme immunoassay. Since apoptosis has been shown to be an important factor in the growth control of various untransformed and neoplastic cell populations, the pharmacological induction of apoptosis in epiretinal membranes could result in a new approach toward inhibiting cellular proliferation in PVR.

Adult↗
PubMed1996

CD 95 expression in traumatic proliferative vitreoretinopathy: a target for the induction of apoptosis.

Apoptotic cell death is a central mechanism underlying growth regulation in normal and pathologic neoplastic and nonneoplastic tissue formation. Apoptosis has also been detected in traction membranes of patients with proliferative vitreoretinopathy (PVR). Herein we report that CD 95 (Fas/APO-1), the cell-surface receptor for a potent proapoptotic cytokine, the CD 95 ligand, is expressed in traction membranes of patients with traumatic PVR. Retinal pigment epithelial (RPE) cells, which are thought to contribute to traction membrane formation, express CD 95 in vitro. However, these cells are resistant to CD 95 antibody-induced apoptosis, presumably because they synthesize cytoprotective proteins, which interfere with the CD 95-dependent killing cascade. Coexposure to inhibitors of RNA or protein synthesis sensitizes human RPE cells for CD 95-mediated apoptosis. In contrast, these agents have little effect on the resistance of these cells to tumor necrosis factor-alpha(TNF-alpha). Pre-exposure to TNF-alpha augments CD 95-mediated killing but not its own toxicity in the presence of inhibitors of RNA and protein synthesis. Preexposure to cycloheximide does not abrogate CD 95-mediated apoptosis, suggesting that labile, short-lived proteins do not mediate the cytotoxic effects of CD 95 antibodies. Taken together, our data indicate that immune-mediated CD 95-dependent killing of proliferating cells in vitreoretinal traction membranes might occur in vivo and could possibly be enhanced using novel approaches of immunopharmacotherapy.

Adolescent↗
PubMed1995

CD95 (Fas/APO-1) antibody-mediated apoptosis of human retinal pigment epithelial cells.

CD95 (Fas/APO-1) is a cytokine receptor protein that signals apoptosis. Here we report that human retinal pigment epithelial cells express CD95 but are rather resistant to agonistic CD95 antibodies. Resistance to CD95 antibodies is overcome by preexposure to the cytokines, tumor necrosis factor-alpha or interferon-gamma, or by coexposure to CD95 antibodies and inhibitors of RNA or protein synthesis. The cells are resistant to tumor necrosis factor-alpha even in the presence of cycloheximide and only moderately sensitized to tumor necrosis factor-alpha-mediated toxicity by coexposure to actinomycin D. CD95-mediated apoptosis is inhibited by dexamethasone both after cytokine sensitization and upon coexposure to CD95 antibodies and actinomycin D or cycloheximide. Induction of apoptosis via CD95 may be involved in the regulation of retinal pigment epithelial proliferation at the vitreoretinal interface.

Antigens, Surface↗
PubMed1995

Pathogenesis of retinal detachment associated with morning glory disc.

Pars plana vitrectomy was performed on a six-year-old boy with complete retinal detachment associated with a morning glory disc of his left eye. Perfluorodecalin was injected to unfold the retina. During surgery, perfluorodecalin leaked repeatedly under the retina. This case demonstrates that a retinal hole in tissues lying within the optic disc anomaly provides a communication for fluid and perfluorodecalin between the subretinal space and vitreous cavity resulting in a rhegmatogenous retinal detachment in the morning glory syndrome.

Child↗
PubMed1995

[Intraocular silicone lenses and silicone oil].

BACKGROUND: Foldable silicone intraocular implants are becoming more popular in conjunction with small incision phacoemulsification. PATIENTS: We observed three patients with silicone oil droplets adherent to the posterior surface of the silicone implant, following silicone oil removal after preceding vitreoretinal surgery with the installation of silicone oil. These droplets could not be dislodged intraoperatively either with focal aspiration or irrigation. They interfered with the patients subjective visual acuity. For this reason, we performed an exchange of the silicone intraocular implant against a PMMA one-piece lens in all three cases. RESULTS: This procedure resulted in an increase of the visual acuity. The mechanism of adherence between the two silicone polymers is finally not known. CONCLUSIONS: With increased use of implantable silicone intraocular lens and silicone oil this complication may be encountered more frequently. Therefore, implantation of silicone lens in vitreoretinal high risk eyes should avoided.

Aged↗
PubMed1995

[Idiopathic macular foramen: new aspects of staging and possible therapeutic concepts].

Idiopathic macular hole and its early stages raises one of the most fascinating subjects in retinal disease. In this review, we aim to summarize the current knowledge of pathogenesis, the recent classification and the strategies for therapy. Recent evidence strongly suggests tangential traction induced by a thin epiretinal membrane to be the main cause for idiopathic senile macular holes. A thickening of the epicortical vitreous membrane or the internal limiting membrane of the retina could be demonstrated in these cases. When such a precursor situation (stage I) is present, in many cases there will be a progression to a full thickness macular hole (stage II). Further traction usually causes an enlarging of the defect in these eyes and the classic appearance of macular holes (stage III-IV) can then be observed. The clinical appearance, the diagnosis and the strategies of treatment are discussed for all stages of idiopathic senile macular holes. Based on the deeper insight into macular hole development, prophylactic vitrectomy and removal of the epiretinal membrane in cases of stage I macular holes, has been considered in order to prevent a further progression of the disease. There is also evidence that in stages II-IV macular holes, a closure of the hole and a visual improvement can be gained by vitrectomy, removal of the epiretinal membrane and fluid-gas exchange. The additional application of biological modifiers (transforming growth factor-beta, human autologous serum or tissue glue) may enhance the adhesion of the detached retina and therefore lead to better anatomical and functional success rates. The results of the pilot studies are reviewed and the surgical techniques as well as the possible complications are discussed.

Blood Proteins↗
PubMed1995

Epidermal dipeptide: a new regulatory factor in proliferative vitreoretinopathy.

Proliferative vitreoretinopathy (PVR) is the most severe complication of retinal detachment surgery, occurring approximately in one out of ten operated eyes. The proliferation of retinal pigment epithelial (RPE) cells and fibroblasts is a cornerstone in the pathogenesis of PVR. Since inhibitory peptides may take a part in the feedback mechanism underlying this proliferation, we assessed the effect of synthesized epidermal dipeptide, pyroglu-glyOH (EDP), on the proliferation of RPE cells and fibroblasts in vitro. The maximum inhibitory effect of EDP on the RPE cells was reached at concentrations ranging from 1.07*10(-13) to 1.07*10(-15) M. Its inhibitory effect on fibroblasts followed a similar pattern at all concentrations applied, 1.07*10(-6) to 1.07*10(-15) M. These results enhance the possibility that PVR may be due to an imbalance of inhibition/disinhibition mechanism under participation of several regulatory molecules like EDP. EDP might have the potential for reducing the risk of PVR.

Animals↗
PubMed1995

Onset and recurrence of proliferative vitreoretinopathy in various vitreoretinal disease.

AIMS: This study aimed to evaluate both the mean time intervals between retinal disease and the development of proliferative vitreoretinopathy (PVR) and the time intervals at which recurrent PVR develops following various kinds of vitreoretinal disease and surgery. METHODS: One hundred and thirty six consecutive cases of PVR that were seen and operated on between 1991 and 1994 were evaluated retrospectively. Intervals between onset of disease and PVR or recurrent PVR were noted. Conditions leading to PVR, surgical procedures, and the final anatomical and functional results were evaluated. RESULTS: Before PVR was noted for the first time, an average of 1.06 vitreoretinal surgical procedures were performed (range 0 to 3). A mean of 1.99 surgeries were performed to control PVR or to reach an end stage where further surgery would have been unreasonable (range 0 to 5). The average (median) time interval between the onset of the retinal disease and PVR was 2.0 months (range 0.5 to 45 months). The median time intervals between surgery and recurrence for the second, third, or fourth times was also 2.0 months (range 0.5 to 34 months). CONCLUSIONS: PVR starts earliest at 2 weeks after an event and subsequently quietens down within a maximum of 45 months after treatment (median 2 months). PVR may recur more than once but the time course of the disease is likely to be the same for each recurrence.

Adolescent↗
PubMed1995

Intercellular adhesion molecule-1 levels in plasma and vitreous from patients with vitreoretinal disorders.

Intercellular adhesion molecule 1 (ICAM-1) is a member of the immunoglobulin superfamily with important functions in immune activation and inflammation. Its interaction with different cytokines [interleukin 1 (IL-1), tumor necrosis factor-alpha (TNF-alpha), interferon-gamma (IFN-gamma)] is important for lymphocyte migration into inflammatory sites. We used a sandwich enzyme immunoassay (EIA) for the quantitative determination of soluble ICAM-1 (cICAM-1) in vitreous and plasma from patients undergoing vitrectomy for a variety of proliferative vitreoretinal disorders. The values obtained were compared with the total vitreal protein. The respective concentrations of cICAM-1 in vitreous were as follows control samples, 3.47 +/- 1.84 ng/ml; proliferative diabetic retinopathy (PDR) of diabetes type I 27.43 +/- 14.72 ng/ml; PDR of diabetes type II, 32.46 +/- 10.31 ng/ml; idiopathic proliferative vitreoretinopathy 35.74 +/- 15.30 ng/ml; and traumatic PVR, 45.23 +/- 24.24 ng/ml. Plasma samples yielded the following concentrations: controls, 415 +/- 43.4 ng/ml; PDR of diabetes type I, 469 +/- 96.9 ng/ml; PDR of diabetes type II, 425 +/- 65.4 ng/ml; idiopathic PVR, 402 +/- 119.9 ng/ml; and traumatic PVR, 434 +/- 118.6 ng/ml. Our results demonstrate high levels of ICAM-1 in most proliferative vitreoretinal disorders. In PDR and in traumatic PVR, cICAM-1 levels were elevated significantly more than were total vitreal protein levels. In traumatic PVR, patients with a short interval between previous surgery or traumatic event demonstrated the highest levels of cICAM. Since plasma levels were not significantly altered, we suggest that local cICAM-1 production, possibly from macrophages, may be of importance in the early phase of PVR and PDR by enhancing immune activation and inflammation.

Diabetes Mellitus, Type 1↗