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Christos Haritoglou

Publications and source records attributed to Christos Haritoglou.

At least 19 recordsLinked to original sources
PubMed2007

Pulsed electron avalanche knife: new technology for cataract surgery.

BACKGROUND: The pulsed electron avalanche knife (PEAK-fc) is a new pulsed electrosurgical device that allows for precise, "cold" and traction-free tissue dissection. AIM: To evaluate the surgical applicability, safety and potential complications of PEAK-fc in complicated cataract surgery. METHODS: The study included five children with congenital cataracts, two patients with advanced senile cataracts, six adults with mature cataracts, three of them with posterior iris synechia, three patients with post-traumatic cataracts with zonulolysis, one patient with intumescent traumatic cataract and three patients with massive anterior capsule opacification. Anterior and posterior capsulotomies, iris synechiolysis, dissection of anterior capsule opacification and fibrotic scar tissue were performed. PEAK-fc was set at voltages of 500-700 V, pulse duration of 0.1 m and repetition rate of 40-100 Hz. RESULTS: Anterior and posterior capsulotomies were successfully and safely performed in all eyes. The edges of capsulotomies appeared sharp, showing only limited collateral damage. PEAK-fc worked best by just gently touching the capsule, thereby avoiding tractional forces or pressure on the lens capsule. Posterior iris synechiae could be released and anterior capsule opacification was dissected without complications. CONCLUSIONS: PEAK-fc is a very helpful cutting device for complicated cases of cataract surgery, especially for mature and congenital cataracts, traumatic zonulolysis or anterior segment complications after intraocular inflammation.

Adolescent↗
PubMed2006

Visual quality of life after macular hole surgery: outcome and predictive factors.

BACKGROUND: In the present study we evaluated the functional success after macular hole surgery in correlation to visual quality of life and looked for predictive factors determining surgical success. METHODS: Fifty-nine patients that underwent pars plana vitrectomy for idiopathic macular hole were included. Follow-up visits were performed in regular intervals after surgery and included a clinical examination, optical coherence tomography (OCT) and measurement of visual acuity. To assess the visual quality of life patients filled out the National Eye Institute 25-item Visual Function Questionnaire (VFQ-25) before and three months and one year after surgery. RESULTS: Macular hole closure was achieved in 57 of 59 patients (97%). Mean visual acuity increased from 20/100 preoperatively to 20/34 one year after surgery (p = 0.02). Despite good visual acuity (20/27) in the fellow eye, visual quality of life (VFQ composite score) rose from 75.9 +/- 14.4 (SD) to 81.5 +/- 14.2 one year after surgery (p<0.001). Although there was no correlation between the increase in visual quality of life and visual acuity, the increase in VFQ-25 could be well predicted: low visual acuity and significant impairment on VFQ-25 testing preoperatively made patients most likely to benefit from macular hole surgery. A relatively high retinal thickness measurement at the hole border measured on OCT further increases the predictive value. CONCLUSION: Macular hole surgery is associated with an increase in visual quality of life despite good visual acuity of the fellow eye. Preoperative visual acuity, VFQ-25 value and partly OCT may help to predict the increase in patients' vision related quality of life after surgery.

Aged↗
PubMed2006

Light absorbing properties of indocyanine green (ICG) in solution and after adsorption to the retinal surface: an ex-vivo approach.

BACKGROUND: To evaluate potential differences in light absorbing properties and stability of indocyanine green (ICG) adsorbed to the retinal surface and of ICG dissolved in water and balanced salt solution. METHODS: The retina of four human donor eyes was prepared by removing the vitreous from the retinal surface. The inner surface of the specimen was covered with two to three drops of a 0.05% or 0.15% ICG solution respectively. After 1 min, the dye was removed by careful irrigation using BSS plus. The retinal specimens were then investigated by diffuse reflection spectroscopy (UV/VIS/NIR Spectrometer Lambda 900/Perkin Elmer equipped with a PELA-1020 integrating sphere accessory) and their absorption evaluated by the Kubelka-Munk function. To control the sensitivity of the setting, diffuse reflectance spectra of ICG adsorbed to a cellulose membrane and Al(2)O(3) were measured. For comparison, absorption spectra of ICG dissolved in water and BSS plus solution were measured in relation to ICG concentration and time using an UV/VIS/NIR Spectrometer Lambda 900/Perkin Elmer. RESULTS: On the retinal surface, absorption spectra exhibited a steep increase of absorption beginning at 620 nm, with a maximum at 736 nm (0.05%) and a shoulder at 745 (0.15%) and a second maximum at approximately 800 nm for both concentrations. Repeated measurement of the retinal surface 13 days after the ICG exposure revealed no changes in the position of the maxima as compared to the initial measurements. Light absorbing properties of ICG on cellulose or Al(2)O(3) are similar to those seen on the retinal surface with respect to the pattern and location of absorption maxima. In contrast, ICG dissolved in water or BSS plus disclosed variations in absorption characteristics depending on dye concentration, solute and time of measurement. CONCLUSIONS: Absorption characteristics and stability of ICG bound to the retinal surface could be of relevance when investigating potential pathomechanisms of ICG related toxicity, which might be related not only to intraoperative but also to postoperative light exposure of patients after intravitreal use of ICG.

Acetates↗
PubMed2006

Ultrastructure of the vitreomacular interface in full-thickness idiopathic macular holes: a consecutive analysis of 100 cases.

PURPOSE: To evaluate the ultrastructure of the vitreoretinal interface in stage III and stage IV idiopathic macular holes. DESIGN: A consecutive observational case series, laboratory investigation. METHODS: Pars plana vitrectomy with en-bloc removal of the internal limiting membrane (ILM) and epimacular tissue was performed by one surgeon in 80 eyes with stage III macular holes and in 20 eyes with stage IV macular holes. In total, 218 specimens were processed for light and transmission electron microscopy. RESULTS: Fibrocellular proliferation at the vitreal side of the ILM was found in 57 cases. Native vitreous collagen (NVC) was attached to the ILM in 36 eyes. The presence of NVC was considerably more frequent in eyes with stage IV (70%) than in eyes with stage III macular holes (26%). Mono- and multilayered cellular membranes were seen more frequently in stage IV macular holes. NVC, if present, was always associated with fibrocellular proliferation. In 39 eyes with stage III and in four eyes with stage IV macular holes, the ILM was devoid of any cells and collagen. CONCLUSIONS: Fibrocellular proliferation appears to be a secondary event instead of a primary feature in macular hole development. The severity of fibrocellular proliferation is associated with the presence of NVC. Incomplete vitreoretinal separation may contribute to the development of epimacular membranes in eyes with idiopathic macular holes. Remnants of the vitreous cortex remain more often attached to the ILM in eyes with spontaneous posterior vitreous detachment (PVD) than in eyes with surgical PVD induction.

Aged↗
PubMed2006

Pulsed electron avalanche knife for capsulotomy in congenital and mature cataract.

The pulsed electron avalanche knife (PEAK-fc, Carl Zeiss Meditec) is an electrosurgical cutting device that allows precise "cold" and traction-free tissue dissection. We describe its applicability and safety for anterior capsulotomy in a child with congenital cataract and an adult patient with mature cataract. The PEAK-fc was set at a voltage of 600 V and a pulse repetition rate of 80 Hz. Anterior capsulotomies were successfully and safely performed in both cases, with the edges of capsulotomies appearing sharp and showing only limited collateral damage. The PEAK-fc appears to be a helpful cutting device for complicated cases of cataract surgery, especially for mature and congenital cataracts.

Cataract↗
PubMed2006

Evaluation of the internal limiting membrane after conventional peeling during macular hole surgery.

We evaluated the histologic features of the internal limiting membrane (ILM) of the retina removed during macular hole surgery without indocyanine green staining. Our investigation focused on the presence or absence of retinal structures adherent to the retinal surface of the ILM. Because only tiny retinal cellular fragments were observed especially in ILM folds, we conclude that conventional ILM peeling can be performed safely with a cleavage plane between the retinal surface of the ILM and Müller cell endfeet.

Aged↗
PubMed2006

Immunohistochemical findings after LASIK confirm in vitro LASIK model.

PURPOSE: To compare immunohistochemical findings in human donor corneas after successful laser in situ keratomileusis (LASIK) without clinical complications with a recently established human LASIK in vitro model. METHODS: Donor corneas with prior LASIK treatment were investigated. Cryostat sections were stained immunohistochemically for collagen types I, III, and VI and laminin and fibronectin. RESULTS: With light microscopy, the interface of the LASIK flap could hardly be detected. In all samples, fibronectin was consistently detected along the entire extent of the surgical wound. In contrast, collagen type III and laminin only stained the superficial portion of the LASIK incision site. Staining for collagen types I and VI showed no changes after LASIK. CONCLUSION: Histologic findings in donor corneas with prior LASIK treatment confirm histologic observations in a recently introduced human organ culture LASIK model. This strengthens the reliability of the latter LASIK model for further studies concerning wound healing after LASIK surgery.

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

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

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↗