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Biomedical subjects

Anselm Kampik

Publications and source records attributed to Anselm Kampik.

At least 37 records · Page 2Linked to original sources
PubMed2006

Comparison of optical coherence tomography and fundus photography for measuring the optic disc size.

PURPOSE: To assess the agreement and repeatability of optic nerve head (ONH) size measurements by optical coherence tomography (OCT) as compared to conventional planimetry of fundus photographs in normal eyes. METHODS: For comparison with planimetry the absolute size of the ONH of 25 eyes from 25 normal subjects were measured by both OCT and digital fundus photography (Zeiss FF camera 450). Repeatability of automated Stratus OCT measurements were investigated by repeatedly measuring the optic disc in five normal subjects. RESULTS: Mean disc size was 1763 +/- 186 vertically and 1632 +/- 160 microm horizontally on planimetry. On OCT, values of 1772 +/- 317 microm vertically (p = 0.82) and a significantly smaller horizontal diameter of 1492 +/- 302 microm (p = 0.04) were obtained. The 95% limits of agreement were (-546 microm; +527 microm) for vertical and (-502 microm; +782 microm) for horizontal planimetric compared to OCT measurements. In some cases large discrepancies existed. Repeatability of automatic measurements of the optic disc by OCT was moderately good with intra-class correlation coefficients (ICC) of 0.78 horizontally and 0.83 vertically. The coefficient of repeatability indicating instrument precision was 80 microm for horizontal and 168 microm for vertical measurements. CONCLUSIONS: OCT can be used to determine optic disc margins in moderate agreement with planimetry in normal subjects. However, in some cases significant disagreement with photographic assessment may occur making manual inspection advisable. Automatic disc detection by OCT is moderately repeatable.

Adult↗
PubMed2006

Galectin-1 influences migration of retinal pigment epithelial cells.

PURPOSE: To determine whether the beta-galactoside-binding matricellular protein Gal-1 is expressed in human specimens of proliferative vitreoretinopathy (PVR) and to evaluate its influence on RPE migration. METHODS: RT-PCR was used to detect Gal-1-specific transcripts in PVR membranes, and the expression pattern of Gal-1 was examined by immunohistochemistry. Expression of Gal-1 in native, low- and high-density cultured RPE cells was determined by Western blot analysis. Cultured human RPE cells were treated with bFGF, TGF-beta2, PDGF-BB, or HGF. The dose-response of Gal-1 mRNA expression was measured by by real-time quantitative RT-PCR and Northern blot analysis. Induction of Gal-1 protein was confirmed by Western blot analysis. To study the effect of Gal-1 on RPE migration in vitro, Gal-1 expression was silenced by RNA interference. beta-Lactose was used to saturate extracellular galectins. RPE cell migration was assessed by a modified Boyden chamber assay, with HGF as the chemoattractant. RESULTS: Gal-1 mRNA expression was present in human specimens of PVR membranes, and staining for Gal-1 was distributed throughout the extracellular matrix (ECM) of PVR membranes. Colocalization was found with laminin and fibronectin and cells of epithelial origin. Western blot analysis revealed greater baseline expression levels in low-density cultured RPE cells than in native and high-density cultured RPE cells. Treatment with HGF caused a dose-dependent increase in Gal-1 expression. Low expression levels of Gal-1 correlated with a reduction of RPE migration to 14% of control. beta-Lactose inhibited HGF-induced RPE cell migration to 23% of control. CONCLUSIONS: Gal-1 is present in the extracellular matrix of PVR membranes and may be derived from dedifferentiated RPE cells. The expression level of Gal-1 appears to be related to a migratory RPE phenotype and stimulation by HGF, both conditions implicated in the pathogenesis of early PVR. Furthermore, HGF-induced RPE migration may be dependent, at least in part, on Gal-1- and beta-galactoside-dependent mechanisms.

Adolescent↗
PubMed2006

Inhibition of human retinal pigment epithelial cell attachment, spreading, and migration by alkylphosphocholines.

PURPOSE: To investigate the effect of alkylphosphocholines (APCs) on human retinal pigment epithelium (RPE) attachment, spreading, migration, and microfilament assembly in vitro. METHODS: Cultured RPE cells of five human donors were treated with one of four APCs (C18:1-PC, C20:1-PC, C21:1-PC, or C22:1-PC) in the presence of fetal calf serum. Cell viability was tested by the trypan blue exclusion assay. Attachment was assessed after a 2-hour incubation of RPE cells on coated 96-well-plates and subsequent MTT testing. Cellular spreading is characterized by cytoplasmic halo formation and was quantified by counting four separate fields of RPE cells allowed to spread on coated 24-well plates for 4 hours. Migration was measured by a modification of the Boyden chamber method in microchemotaxis chambers with polycarbonated filters. Microfilament assembly was assessed by immunofluorescence analysis after incubation with rhodamine-phalloidin. RESULTS: All four APCs inhibited RPE cell attachment by more than 70% of their IC50 (C18:1-PC: 30 microM; C20:1-PC: 10 microM; C21:1-PC: 10 microM; and C22:1-PC: 10 microM). Also, APCs inhibited RPE cell spreading by more than 80% and migration by more than 90% at similar concentrations. Trypan blue staining revealed a toxicity within control limits within the concentration interval tested. Microfilament organization was significantly disturbed after incubation of RPE cells with one of the four APCs close to its IC50. CONCLUSIONS: APCs inhibit RPE cell attachment and spreading in vitro at nontoxic concentrations. As a possible mechanism of action, APCs disturb microfilament assembly, since they are known to interfere with protein kinase C (PKC) function. This could represent a novel method of preventing even early stages of proliferative vitreoretinal diseases like proliferative vitreoretinopathy (PVR).

Actin Cytoskeleton↗
PubMed2006

Potential role of tissue transglutaminase in glaucoma filtering surgery.

PURPOSE: Scarring of the filtering bleb site is the main cause of failure in glaucoma filtration surgery. In the present study, the role of tissue transglutaminase (tTgase) in the accumulation of extracellular matrix (ECM) proteins in these scars was investigated. Transglutaminases are enzymes capable of cross-linking ECM proteins to proteolysis-resistant complexes. METHODS: Expression of tTgase, its reaction product epsilon-(gamma-glutamyl)-lysine, and fibronectin and their colocalization were investigated immunohistochemically in failed blebs and in an in vitro trabeculectomy model. Failed blebs were analyzed by RT-PCR for the presence of tTgase mRNA. Human Tenon fibroblasts (HTFs) were treated with transforming growth factor-beta2 (TGF-beta2). The effect was studied with immunohistochemistry, Northern blot analysis, and Western blot analysis. tTgase activity was assayed by incorporation of biotinylated cadaverine into fibronectin. RESULTS: Expression of tTgase and epsilon-(gamma-glutamyl)-lysine was present in all failed blebs. Staining was most prominent at the rim of the Tenon cyst. In the in vitro trabeculectomy model, tTgase and epsilon-(gamma-glutamyl)-lysine were barely present at the incision side of the flap but were perspicuously increased by TGF-beta2 treatment. Enzyme and its reaction product were colocalized with fibronectin. Cultured HTFs contained a basal level of tTgase mRNA. After treatment with TGF-beta2, expression and activity of tTgase significantly increased. CONCLUSIONS: The findings demonstrated that tTgase is present and functionally active in failed blebs. Expression and activity of tTgase appeared to be stimulated by TGF-beta2, a growth factor known to be increased in primary open angle glaucoma. Intervention at this pathway might open a new approach to prevent scarring after glaucoma filtration surgery.

Adult↗
PubMed2006

Administration of novel dyes for intraocular surgery: an in vivo toxicity animal study.

PURPOSE: To investigate the effect of intravitreal injections of new vital dyes on the retina, the retinal pigment epithelium (RPE) and the choroid in an in vivo rat model. METHODS: Rats were injected intravitreally with four dyes: light-green SF yellowish (LGSF), copper(II)phthalocyanine-tetrasulfonic acid (E68), bromphenol blue (BPB), and Chicago blue (CB) dissolved in physiologic saline solution (PSS) at concentrations of 0.5% and 0.02%. PSS served as the control. Additional animals were treated with single injections of 0.5%, 0.02%, 0.002%, and 0.0002% ICG or 0.002% E68 into one eye. Adverse effects on anterior and posterior segments were evaluated by slit lamp biomicroscopy and ophthalmoscopy. Retinal toxicity was assessed by histology and retinal ganglion cell (RGC) quantification 7 days after dye administration. RESULTS: Eyes treated with 0.5% E68, 0.5% ICG, or 0.5% CB showed discrete staining of both cornea and lens not seen at lower concentrations or with other dyes. Histology revealed dose-dependent reactions after E68 administration. ICG 0.5% induced significant thinning of inner retinal layers compared with PSS. ICG 0.02% caused focal degenerative changes of the outer retina in three of seven eyes, whereas 0.002% and 0.0002% ICG did not. CB led to heterogeneous morphologic alterations. BPB- or LGSF-treated eyes showed normal retinal morphology. ICG at all tested concentrations induced significant RGC loss, as did E68 at 0.5% but not at lower concentrations. CONCLUSIONS: BPB or LGSF produced no significantly detectable toxic effects on the retina in vivo. The safety of these new dyes must be established in other models and/or in preclinical studies before the clinical use of any of these dyes.

Animals↗
PubMed2006

Keratinocyte transglutaminase in proliferative vitreoretinopathy.

PURPOSE: Proliferative vitreoretinopathy (PVR) is an excessive wound-healing process and the major complication in rhegmatogenous retinal detachment. The present study was designed to investigate the expression of keratinocyte transglutaminase (kTgase) in PVR membranes and retinal pigment epithelial (RPE) cells and to evaluate its expression in response to growth factors known to be increased in PVR disease. METHODS: Distribution of kTgase and its relation to fibronectin have been investigated immunohistochemically. PVR membranes and native and cultured RPE cells were analyzed by RT-PCR for the presence of kTgase mRNA. In vitro, RPE cells were treated with transforming growth factor (TGF)-beta2, basic fibroblast growth factor, interleukin-6, and interleukin-1beta. Expression of kTgase was studied by Northern and Western blot analysis. The effect of connective tissue growth factor (CTGF) silencing on the TGF-beta2-modulated expression of kTgase was investigated by transfection with CTGF small interfering (si)RNA before TGF-beta2 treatment. RESULTS: mRNA expression of kTgase was present in all PVR membranes. Immunohistochemical staining for kTgase showed an inhomogeneous pattern with localized accumulation and little colocalization with fibronectin. Although native RPE cells contained only a basal level of kTgase mRNA, the expression of kTgase was increased under culture conditions and was further enhanced by TGF-beta2 treatment. Silencing of CTGF expression did not attenuate the TGF-beta2-mediated induction of kTgase. CONCLUSIONS: The findings demonstrate that kTgase is present in PVR membranes. Its amount is related to the differentiation state of RPE cells and stimulation by TGF-beta2. TGF-beta2-mediated increase seems to be independent of CTGF.

Adolescent↗
PubMed2005

Mapping of the retinal pigment epithelium in exudative age related macular degeneration.

PURPOSE: To evaluate a novel technique for three-dimensional mapping of the retinal pigment epithelium (RPE) layer in patients with subfoveal choroidal neovascularization (CNV) due to age-related macular degeneration. METHODS: Scanning with a recent generation retinal thickness analyzer (RTA) was performed in consecutive patients undergoing fluorescein angiography. From a 3 x 3 mm area centered on the fovea, three-dimensional area maps of the RPE level were calculated by external spreadsheet software. Included were 18 eyes with classic CNV, 18 eyes with occult CNV and 18 eyes from age-matched normal subjects. Repeatability was assessed by measuring 17 eyes with CNV 3 times. In ten additional patients, RTA imaging results were compared with cross-sections obtained by optical coherence tomography. RESULTS: By both methods, distinctive changes in RPE level maps were observed in classic and occult CNV. In classic CNV with the lesion extending over the RPE, only focal irregularities in the anteriorly displaced RPE surface were observed. In contrast, mapping of occult CNV showed a more irregular displacement of the RPE layer. The RPE map standard deviation indicating surface irregularity differed statistically significantly between the groups, with coefficients of variance of 5.9% for controls, 6.1% for classic and 8.8% for occult CNV (P < 0.001). Regarding repeatability, RPE level maps showed 1.2% coefficient of variance and an intra-class correlation coefficient of 0.87 for triplicate measurements in CNV patients. CONCLUSIONS: Topographic mapping of CNV lesions offers a fast, reproducible method for obtaining three-dimensional morphometric information on the RPE level and to quantify changes.

Adult↗
PubMed2005

Age effect on retina and optic disc normal values.

PURPOSE: To investigate retinal thickness and optic disc parameters by the Retinal Thickness Analyzer (RTA) glaucoma program in older normal subjects and to determine any age effect. METHODS: Subjects over 40 years of age without any prior history of eye diseases were recruited. Only subjects completely normal on clinical ophthalmologic examination and on visual field testing by Humphrey Field Analyzer (HFA) using the SITA 24-2 program were included. A total of 74 eyes from 74 subjects with even age distribution over the decades were enrolled and underwent topographic measurements of the posterior pole and of the optic disc by RTA. The 'glaucoma full' program in software version 4.11B was applied. RESULTS: Mean patient age was 59.9 +/- 10.3 years with a range from 40 to 80 years. The only parameter intraocular pressure (IOP) correlated with was retinal posterior pole asymmetry (r = 0.27, p = 0.02). IOP itself increased significantly with age (r = 0.341, p = 0.003). Mean defect and pattern standard deviation of the HFA did not correlate with any of the retinal or optic disc measurements. Increasing age correlated significantly with some of the morphologic measurements of the RTA: decreasing perifoveal minimum thickness (r = -0.258, p = 0.026), increased cup-to-disc area ratio (r = 0.302, p = 0.016) and increased cup area (r = 0.338 p = 0.007). CONCLUSIONS: An age effect exists for some of the retina and optic disc measurements obtained by the RTA.

Adult↗
PubMed2005

Comparison of prednisolone 1%, rimexolone 1% and ketorolac tromethamine 0.5% after cataract extraction: a prospective, randomized, double-masked study.

PURPOSE: To compare the efficacy, safety and patient comfort of two topical steroids (prednisolone 1% and rimexolone 1%) and a topical non-steroidal anti-inflammatory agent (ketorolac tromethamine 0.5%) after extracapsular cataract extraction. METHODS: Forty-five patients were enrolled in this prospective, randomized, double-blind study. They were assigned to receive topical treatment with either prednisolone, rimexolone or ketorolac tromethamine ophthalmic solution after phacoemulsification for cataract extraction. On postoperative days 1, 3, 5, 14 and 28 best-corrected visual acuity, intraocular pressure (IOP), slit-lamp examination of the anterior segment and report of the patients' comfort were assessed and compared by Friedman rank time analysis. RESULTS: Regarding the primary outcome efficacy of inflammation control the assessment of cells did not differ (p=0.165), while flare in the anterior chamber was lowest (p=0.008) in the non-steroidal anti-inflammatory drug (NSAID) group. Surface inflammation was lowest with prednisolone (p=0.002). Regarding safety, visual acuity did not differ among the groups. In the prednisolone group one patient, however, responded to steroid treatment with elevated IOP and had to be excluded. In the remaining patients IOP was even lower in the two steroidal treatment groups than with ketorolac (p=0.030). One patient receiving ketorolac had to be excluded because a corneal erosion developed. Patient comfort was highest with prednisolone (p=0.041). CONCLUSIONS: Ketorolac tromethamine provides good control of intraocular inflammation after cataract extraction without the risk of a steroidal IOP increase, which was also not observed under rimexolone therapy. The best surface inflammation control and patient comfort was observed with prednisolone, which remains a good choice.

Administration, Topical↗
PubMed2005

Pulsed electron avalanche knife (PEAK-fc) for dissection of retinal tissue.

OBJECTIVE: To evaluate the effectiveness and precision of tractionless retinal tissue dissection by the advanced version of the pulsed electron avalanche knife for fine cutting (PEAK-fc; Carl Zeiss Meditec, Jena, Germany). METHODS: Porcine retina (in vivo) and human retina (in vitro) were incised with the PEAK-fc using various pulse parameters. The globes were then processed for light microscopy. Evaluation of all specimens focused on depth of the retinal cuts and on the degree of collateral damage. RESULTS: Retinal cuts performed both in vivo on porcine eyes and on human donor eyes showed very sharp edges with only little collateral damage. With probes of 600 mum in length, the optimal pulse parameters for precise and reproducible cutting of the retina were an amplitude of 350 to 380 V, a repetition rate of 300 Hz, and 30 "minipulses" per pulse of 100-microsecond duration. With increasing voltage, cuts also affected the retinal pigment epithelium and the choroid, followed by intravitreal bleeding during in vivo application. CONCLUSION: We demonstrated that PEAK-fc is capable of precisely cutting retinal tissue in vivo and in vitro using optimal pulse parameters. Further in vivo studies will be necessary to determine the efficacy of this new tractionless cutting device in vitreoretinal surgery.

Adult↗
PubMed2005

Epiretinal pathology of diffuse diabetic macular edema associated with vitreomacular traction.

PURPOSE: To investigate the ultrastructure of the vitreomacular interface in patients with diffuse diabetic macular edema (DDME) associated with vitreomacular traction. DESIGN: Laboratory investigation. METHODS: Fifty-five consecutive patients with DDME underwent vitrectomy with en-bloc removal of the inner limiting membrane (ILM) and epimacular tissue. Six patients were operated on both eyes. Sixty-one specimens harvested during vitrectomy were analyzed by electron microscopy. RESULTS: Preoperatively, a thickened premacular cortical vitreous was present in 47 eyes. Native vitreous collagen with single cells interspersed within the collagenous layer or a cellular monolayer were the ultrastructural features in these eyes. Twenty-three eyes showed an epimacular membrane. In eyes with obvious signs of tangential vitreomacular traction, multilayered membranes situated on a layer of native vitreous collagen were found. Fibroblasts and fibrous astrocytes were the predominant cell types; myofibroblasts and macrophages were also present. Sixty of 61 specimens showed native vitreous collagen covering the ILM. Macular edema resolved in 58 eyes and persisted in 3 eyes. No recurrent fibrocellular proliferation was observed during the follow-up period of 18 months (mean, 3 to 56 months). CONCLUSIONS: The vitreomacular interface in eyes with DDME is characterized by a layer of native vitreous collagen and a varying cellular component. Tangential vitreomacular traction is associated with multilayered membranes situated on a layer of vitreous collagen. Resolution of macular edema does not depend on the presence and removal of contractile membranes. In eyes without tangential traction, complete removal of epimacular tissue also leads to fluid resorption.

Adult↗
PubMed2005

Visual loss as a first sign of adult-type chronic myeloid leukemia in a child.

PURPOSE: To report the unusual case of retinal leukemic infiltration in a child with adult-type chronic myelocytic leukemia. DESIGN: Interventional case report. METHODS: Complete ophthalmologic examination, including visual acuity measurement and funduscopy. The diagnosis was established by blood cell counts and confirmed by a positive Philadelphia-chromosome translocation (t [9,22]). Treatment consisted of hydroxyurea and stem-cell transplantation. RESULTS: After therapy, complete regression of the retinal lesion was observed with full recovery of visual acuity. CONCLUSION: This case underlines the importance of interdisciplinary cooperation between ophthalmologists and pediatric oncologists in the diagnosis and treatment of this disease.

Blindness↗
PubMed2005

Absence of scar formation in human donor cornea with prior laser in situ keratomileusis.

PURPOSE: To investigate transglutaminases (enzymes capable of cross-linking extracellular matrix proteins to proteolysis-resistant complexes during scar tissue formation) in a human donor cornea after successful laser in situ keratomileusis (LASIK) without clinical complications and to compare with the results in a human donor cornea with corneal scarring after corneal injury. SETTING: Department of Ophthalmology, Ludwig-Maximilians University, Munich, Germany. METHODS: A donor cornea with prior uneventful LASIK treatment and 1 with corneal scarring after penetrating injury were investigated. Cryostat sections were stained immunohistochemically for tissue transglutaminase (tTG), keratocyte transglutaminase (kTG), and their reaction product epsilon-(gamma-glutamyl)-lysine. RESULTS: With light microscopy, the flap interface of the LASIK-treated eye could hardly be detected, while in the injured eye, infiltration of cells and a clear margin next to the scar formation were present. Immunohistochemistry demonstrated a distinct staining for tTG, kTG, and epsilon-(gamma-glutamyl)-lysine in the corneal scar. In contrast, neither transglutaminase nor epsilon-(gamma-glutamyl)-lysine staining could be observed at the flap margin or in the interface of the LASIK-treated donor eye. CONCLUSIONS: Irreversible protein cross-linking of transglutaminases via epsilon-(gamma-glutamyl)-lysine connections seem to be indicators for scarring in corneal wound healing. The absence of transglutaminases and their reaction product epsilon-(gamma-glutamyl)-lysine in a LASIK-treated cornea supports the idea of missing scar tissue formation after LASIK surgery.

Adult↗
PubMed2005

Staining and peeling of the internal limiting membrane in the cat eye.

PURPOSE: To investigate the cat vitreomacular interface using trypan blue (TB) and indocyanine green (ICG) and to determine the validity of the cat model in terms of staining and peeling of the internal limiting membrane (ILM). METHODS: Lensectomy and vitrectomy were performed in four eyes of two cats. The ILM of two eyes was stained with TB (0.15%). ILM peeling was performed in one eye. Two eyes were stained with ICG (0.5%). One eye was illuminated for 3 min. Light and transmission electron microscopy and confocal microscopy were performed. RESULTS: Clinically, both dyes stained the cat ILM similar to human ILM. TB staining resulted in a normal ultrastructure and antigenity of the retina. ILM peeling was associated with intraretinal bleeding. There were fragments of Müller cells adherent to the retinal side of the ILM, and Müller cell endfeet were ruptured and avulsed. ICG staining of the ILM followed by illumination caused severe inner retinal damage. ICG without illumination resulted in focal ILM detachments associated with tearing of Müller cell endfeet. CONCLUSIONS: The cat can be used as a model to study the effect of TB and ICG on the central area of the cat retina, as previous results from clinical and experimental postmortem settings in human eyes were confirmed in the current study. Peeling of the ILM as a sheet as performed in human macular surgery is not feasible. Differences in the ultrastructure of the ILM and a strong adhesion of the ILM to Müller cell endfeet may account for this observation.

Animals↗