[Radiotherapy in treatment of sub-foveal choroid neovascularization].
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Choroid↗
Biomedical subjects
M Spitznas
Publications and source records attributed to M Spitznas.
Distribution pattern of nervous tissue and peptidergic nerve fibers in accessory lacrimal glands.
PURPOSE: Demonstration of the distribution pattern of nervous tissue and the occurrence of neuropept human accessory lacrimal glands by means of immunohistochemical methods. METHODS: Paraffin sections of tissue samples were incubated with antisera against protein gene product (PGP), S-100 protein (S-100), calcitonin gene-related peptide (CGRP) and substance P (SP). The immunoreactions were visualized using both species-specific secondary antibodies and a streptavidin-biotin-peroxidase complex (ABC method). RESULTS: PGP- and S-100-immunoreactive nerve fibers were distributed in the entire intertubular stroma. In addition, myoepithelial cells, a few clusters of tubulus cells, groups of wandering cells, and scattered cells of the excretory duct system were S-100-immunoreactive. CGRP- and SP-immunoreactivity was found in a few nerve fibers in the intertubular glandular stroma with an association to secretory tubules, blood vessels, intralobular ducts and excretory duct. CONCLUSIONS: These observations are in agreement with findings in the main lacrimal gland.
Adult↗
Detection of eicosanoids in epiretinal membranes of patients suffering from proliferative vitreoretinal diseases.
AIM: Arachidonic acid is metabolised via lipoxygenase to 15-HETE (15-hydroxyeicosatetraenoic acid) and 15-HPETE (15-hydroperoxyeicosatetraenoic acid), which are believed to influence proliferation in tissue culture. 15-HETE is the reduction product of 15-HPETE. Cell proliferation is believed to be decreased by 15-HPETE and increased by 15-HETE. The aim of this study was to investigate epiretinal membranes for the presence of these lipoxygenase products and to compare membranes from different disease processes. METHODS: Epiretinal membranes of 15 patients suffering from proliferative vitreoretinopathy (PVR, n = 7) and proliferative diabetic retinopathy (PDR; n = 8) were removed during vitrectomy and analysed by means of thin layer chromatography. The plates were evaluated by digital image analysis. RESULTS: Both 15-HETE and 15-HPETE were identified in membranes from eyes of patients with PVR and PDR with HETE values significantly higher (p < 0.05) than HPETE values (HETE/HPETE ratio = 5.2). CONCLUSION: This study demonstrates that eicosanoids are present in the epiretinal membrane tissue of patients with PVR and PDR. Considering that HETE increases cell proliferation while HPETE inhibits it, it is conceivable that eicosanoids are an additional factor contributing to the regulation of membrane growth in proliferative retinal disorders. Thus, inhibition of lipoxygenase could be a therapeutic approach in these diseases.
Biomarkers↗
Organ culture of human main and accessory lacrimal glands and their secretory behaviour.
The purpose of this study was to investigate the in vitro viability and secretory behaviour of human main and accessory lacrimal glands using an organ culture technique. We evaluated the influence of the second messengers cAMP and cGMP on secretion. Fragments less than 1 mm3 of main and accessory lacrimal glands as well as conjunctiva were cultured for 2-72 hr at 37 degrees C in an atmosphere consisting of 50% O2, 45% N2 and 5% CO2, using a specially devised culture medium (+/- cAMP or cGMP). The conjunctival tissue served as negative control. Supernatants were assayed for secretory-component-bound IgA, lactoferrin and lysozyme using ELISA. Cultured tissue pieces were embedded in paraffin, serially sectioned, stained and their volumes calculated using an image-analysis system. This enabled us to differentiate between secretory, connective and fatty tissue. Secreted exudate was correlated to the volume of secretory tissue. Viability of cultured organ pieces was determined by electron microscopic examination. Suitable organ culture conditions for human lacrimal glands were successfully established. Electron microscopic examinations proved that the structural characteristics of the organ and the polarity of the individual cells were well preserved up to 22 days of culture. Culture supernatants were assayed for secretory-component-bound IgA, lactoferrin, and lysozyme and showed that the amount of protein secreted increased with time. Upon addition of cAMP (1 x 10(-3) M) and cGMP (4 x 10(-3) M), secretion was elevated in both main and accessory lacrimal glands. An organ culture system for lacrimal glands was developed that maintains their structural and cellular characteristics as well as their secretory function for up to 22 days. We believe that this system mimics the in vitro state of the organ better than monolayer cultures and thus proves to be a valuable tool when examining lacrimal function in vitro. The fact that both cAMP and cGMP enhance secretion may help to shed some light on the cellular pathways human main and accessory lacrimal glands use for signal transduction.
Animals↗
Retino-choroidal oxygen imaging through a fundus camera.
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Animals↗
Immunocytochemical and ultrastructural evaluation of the distribution of nervous tissue and neuropeptides in the meibomian gland.
BACKGROUND: The ultrastructure of the meibomian gland, of its innervation and the localization of neuropeptides in the glandular tissue of the guinea pig and humans are incompletely known. Therefore they have been investigated in the present study. METHODS: The ultrastructure of the tissue was examined using standard transmission electron microscopic techniques. Additional scanning electron microscopy was carried out on rabbit tissue. Antisera against the neuronal marker protein gene product were used to demonstrate the distribution pattern of the nerve fibers. The neuropeptides substance P (SP) and neuropeptide Y (NPY), vasoactive intestinal polypeptide (VIP) and calcitonin gene-related peptide (CGRP) and the neuronal enzyme tyrosine hydroxylase (TH) were identified by their specific antisera. RESULTS: The glands were found to be composed of arrays of alveoli. The outer cells of the alveoli form a germinal layer. Toward the inside of the alveolus the cells are laden with a secretory substance. The cells disintegrate as they approach the excretory duct. Nerve fibers form a plexus around the alveoli. These nerve fibers form synapses à distance to the basal alveolar cells and enter the basal lamina of the capillaries. In guinea pigs many nerve fibers were positive for the neuropeptides SP and NPY and for VIP, and fewer for CGRP and TH; in humans only SP and CGRP were demonstrated. CONCLUSION: Both the density of nerve fibers and the presence of various neuropeptides suggest that the stimulation of the meibomian gland is subject to nervous control.
Animals↗
Influence of oxygen free radicals and free radical scavengers on the growth behaviour and oxidative tissue damage of bovine retinal pigment epithelium cells in vitro.
PURPOSE: This investigation was carried out to ascertain whether oxygen free radicals can influence the growth behaviour and consecutive lipid peroxidation of retinal pigment epithelium (RPE) cells in vitro and whether scavengers can counteract these effects. METHODS: The experimental model was based on calf RPE cells. Hypoxanthine/xanthine oxidase (HX/XO) and superoxide dismutase/ catalase (SOD/CAT) served as the radical generating system and scavengers, respectively. The components were tested alone and in combination. Lipid peroxides were determined in culture supernatants by a thiobarbituric acid assay. RESULTS: Concentrations of up to 100 mumol/l of HX alone and 500/ 1000 microU of XO alone, as well as the application of the scavengers without the radical generating system (HX/XO), had no effect. Dose-related reduction of cell growth and increase of lipid peroxidation were found with HX/XO treatment (single dose of 500 and 1000 microU/ml 24 h after seeding). After application of 500 or 1000 microU/ml of XO, CAT, when given alone (1200 U/ ml), counteracted the effect of the radicals on cell growth and lipid peroxidation; SOD (300 U/ml) had no effect. A combination of SOD and CAT was no better than the effect of CAT alone. CONCLUSION: The prevention of radical-induced reduction of cell growth and lipid peroxidation by scavengers supports trials of therapy using antioxidants and/or free radical scavengers for various ocular syndromes with RPE involvement.
Animals↗
Differential distribution of neuronal markers and neuropeptides in the human lacrimal gland.
BACKGROUND: The present study was undertaken in an attempt to broaden the spectrum of known neuronal markers and neuropeptides in the main lacrimal gland of the human by light-microscopic immunohistochemistry. METHODS: Using antisera against the neuronal markers protein gene product (PGP) and S-100 protein (S-100), the distribution of nerve fibers in the human main lacrimal gland was studied. Vasoactive intestinal polypeptide (VIP), calcitonin gene-related peptide (CGRP), neuropeptide Y (NPY) and tyrosine hydroxylase (TH) were identified by their specific antisera. RESULTS: The nerve fibers are distributed throughout the interstice between the glandular tubules. Associations were also found between nerve fibers and both the interlobular ductal system and blood vessels (mainly arterioles). Within the glandular lobules isolated groups of secretory cells stained positive for S-100 protein. Nerve fibers situated in the glandular interstice between the tubules showed predominantly positive immunoreactions for the neuropeptide VIP, while only very few fibers stained positive for CGRP, NPY and the catecholamine marker TH. Nerve fibers associated with interlobular blood vessels were mainly CGRP and NPY positive and stained only very rarely for VIP. The epithelia of interlobular ducts and excretory ducts were associated with CGRP-immunoreactive nerve fibers. CONCLUSION: The neuropeptides identified in the lacrimal gland indicate the complexity with which a variety of biologic signals regulate and modulate the lacrimal gland.
Animals↗
Effects of allopurinol and steroids on inflammation and oxidative tissue damage in experimental lens induced uveitis: a biochemical and morphological study.
AIMS: To evaluate the effects of allopurinol in lens induced uveitis (LIU) by morphological methods and to compare these effects with those of steroids and a combination of both drugs biochemically and morphologically. METHODS: Lipid peroxides (LPO) of the retinal tissue were determined by two different methods (thiobarbituric acid assay (TBA) and high performance liquid chromatography expressed as malondialdehyde-like substances). Myeloperoxidase (MPO) activity in the iris/ciliary body complex was analysed spectrophotometrically. Histological changes on three morphological levels of LIU eyes were evaluated. RESULTS: Both allopurinol and the combination of allopurinol/prednisolone led to a significant reduction in the increaed retinal LPO values. Prednisolone only revealed significant effects on retinal LPO when being measured with the TBA method. MPO activity in iris and ciliary body was significantly reduced in all therapy groups. The morphological evaluation of the sections by two masked investigators revealed a significant reduction (p < 0.05) in the inflammation score in all therapy groups. Morphometric studies using the QUANTIMED system (Leica, Cambridge) showed significantly reduced values (p < 0.05) in the allopurinol group and in the group receiving prednisolone and allopurinol. Prednisolone alone did not lead to a significant reduction in the values. CONCLUSIONS: The findings show that both allopurinol and steroids exert positive effects on the variables determined in LIU. The effects of steroids are believed to be mostly due to their direct action on inflammatory cells. The recently reported scavenging effects of methylprednisolone should play a minor role in this disease model. Allopurinol and oxypurinol act as direct scavengers of free radicals and hypochlorous acid, which is produced via MPO catalysis, thus leading to a reduction in tissue inflammation and tissue damage.
Allopurinol↗
Effects of different antioxidants on lens-induced uveitis.
For evaluation of the effects of different free-radical scavengers on biochemical changes in lens-induced uveitis (LIU), ten male Wistar rats were sensitized for 8 weeks using bovine lens protein and Freund's adjuvant. The uveitis was induced by disruption of the lens capsule. One group of animals received superoxide dismutase and catalase (SOD/CAT); a second group of animals was treated with vitamin E. Lipid peroxides (LPO) of the retinal tissue and aqueous humor served as parameter of oxidative tissue damage. Glutathione (GSH/GSSG) of the aqueous humor was evaluated as a parameter of the tissue's redox state. For evaluation of the inflammatory response, myeloperoxidase activity (MPO) was determined in the iris/ciliary-body complex. SOD/CAT produced no improvement in the significantly (P < 0.05) elevated MPO and LPO values recorded for untreated control animals. Following vitamin E treatment the GSH/GSSG and LPO values in aqueous humor were markedly improved as compared with controls. Retinal LPO values were significantly (P < 0.05) reduced as compared with controls. No change in MPO levels was observed. The results demonstrate that enzymes such as SOD and CAT do not influence tissue damage at a significant level, whereas radical chain breakers such as vitamin E can do so. However, the inflammatory response itself is not reduced. To achieve global results, drugs are necessary that act on both free radicals produced by noninflammatory pathways and those originating from inflammation.
Animals↗
Oxidative reactions in the tear fluid of patients suffering from dry eyes.
PURPOSE: To evaluate whether products of oxidative and inflammatory reactions are detectable in the tear fluid of patients suffering from dry eyes. METHODS: The tear fluid of 217 patients (397 eyes) was sampled. Criteria for grouping of the patients were (1) basic secretion test ("sicca 1": BST = 0-5 mm, n = 78 eyes; "sicca 2": BST = 6-10 mm, n = 109 eyes) and (2) subjective symptoms (normal BST, burning, foreign body sensations, tearing, dryness of the eyes: n = 78 eyes). One group of healthy patients (normal BST, n = 132 eyes) served as controls. Lipid peroxide levels and myeloperoxidase activity, as parameters for oxidative tissue damage and inflammatory activity, were determined in the tear fluid. Those patients whose consent could be obtained were subjected to the rose bengal test (sicca 1: 56 eyes; sicca 2: 97 eyes; subjective symptoms: 44 eyes; controls: 49 eyes). The correlation between BST and rose bengal test results was calculated. RESULTS: Lipid peroxides were significantly (P < 0.05) higher in the groups sicca 1 and subjective symptoms than in healthy controls, as was the inflammatory activity in groups sicca 1, sicca 2 and subjective symptoms. Additionally, the inflammatory activity in the group sicca 1 was significantly (P < 0.05) higher than in the groups sicca 2 and subjective symptoms. No evidence of a significant correlation between BST and rose bengal test results was observed. CONCLUSIONS: Both oxidative tissue damage and polymorphonuclear leukocytes indicating an oxidative potential occur in the tear film of patients suffering from dry eyes. These reactions lead to severe damage of the involved tissue. Free radicals and inflammation may be involved in the pathogenesis or in the self-propagation of the disease.
Dry Eye Syndromes↗
Local effects of different perfluorochemical agents.
PURPOSE: To clarify whether the prolonged presence of perfluorochemicals (PFC) in the vitreous cavity causes oxidative tissue damage and inflammatory response of the retina and, if so, what the process is. METHODS: After three different perfluorochemicals [perfluorodecalin (C10F18), perfluorooctane (C8F18) and Fluosol-DA (corresponding to a 20% emulsion of 70% PFD and 30% perfluorotripropylamine, C9F21N)] had been in the vitreous cavity of rabbits for 2 weeks, lipid peroxide concentration and myeloperoxidase activity in the retina were determined. RESULTS: Whereas only Fluosol-DA showed significant oxidative damage, the inflammatory activity was significantly increased in all groups. CONCLUSION: The increased myeloperoxidase activity and the observed oxidative damage of the retina seem to be the effect of both perfluorochemical-loaded macrophages and inflammatory-induced lipid peroxidation.
Animals↗
Systemic effects of different perfluorochemical agents.
PURPOSE: An intravitreal injection of Fluosol-DA leads to a higher alteration of the macrophage system of the retina than perfluorooctane and perfluorodecalin administered by the same route. The difference may be due to different kinds of oxidative damage caused by the three chemicals. To test the validity of this assumption, the degree of cell alteration, expressed as reduction of cytoplasmic motility, caused by these three perfluorochemicals was examined. METHODS: Using the hepatic macrophage system of the rat, cell alteration was examined by magnetometry after intravenous application of various perfluorochemicals [emulsified perfluorodecalin (C10F18), perfluorooctane (C8F17Br) and Fluosol-DA (corresponding to a 20% emulsion of 70% perfluorodecalin and 30% perfluorotripropylamine, C9F21N)]. RESULTS: After administration of high doses, all perfluorochemicals led to cytoskeleton alteration. This alteration, expressed as retardation of the relaxation period of ferromagnetic iron oxide particles, was most pronounced after administration of Fluosol-DA. CONCLUSION: The compromising effect of perfluorochemicals is dose dependent and differs among the three compounds tested, with Fluosol-DA showing the greatest decrease in cytoplasmic motility.
Animals↗
Intraocular lens removal from eyes with chronic low-grade endophthalmitis.
Intraocular lenses (IOLs) were removed from 11 eyes with chronic low-grade endophthalmitis after cataract extraction to restore useful vision and prevent recurrence. One anterior chamber lens, one iris-supported lens, and nine posterior chamber lenses were removed. In the eyes with posterior chamber lenses, the posterior capsule was intact; total (n = 7) or partial (n = 2) capsulectomy was performed in these eyes. Aqueous humor specimens obtained at surgery were positive for bacteria in five eyes, but scanning electron microscopy showed bacteria on all removed IOLs and capsular bags. Final best corrected visual acuity was 20/40 or better in seven eyes. Reduced visual acuity, between 20/50 and 20/400 in three eyes and counting fingers in one eye, was related to retinal detachment (n = 2) and age-related macular degeneration (n = 2). Transient hyphema was seen in one eye. With a mean follow-up of 21 months (range 10 to 31 months), no recurrence of inflammation was observed. The results show that negative cultures do not preclude a bacterial cause for infection and that primary IOL removal with partial or total capsulectomy provides a surgical approach to the treatment of chronic low-grade endophthalmitis not responsive to medical therapy.
Aged↗
Pars plana incisions of four patients: histopathology and electron microscopy.
The pathology of pars plana incisions of four patients is described: three with light microscopy and one with light and electron microscopy. Two eyes were removed because of choroidal melanoma, immediately and 8 days after vitrectomy and transvitreous retinal biopsy. Considerable disruption of tissues surrounding the pars plana incisions was observed. Vitreous was incarcerated in the wounds, which healed with granulation tissue. One eye was examined 4 months after vitrectomy for diabetic retinopathy and a failed pars plana filtering operation. It contained fibrovascular ingrowth from all the incisions, infiltrating the vitreous base with granulation tissue and causing vitreous haemorrhage and retinal detachment. One eye was removed 1 year after vitrectomy for anterior hyaloidal fibrovascular proliferation and early phthisis. The wound had fibrous ingrowth histologically and evidence of active fibroplasia.
Adult↗
Indicators of oxidative tissue damage and inflammatory activity in epiretinal membranes of proliferative diabetic retinopathy, proliferative vitreoretinopathy and macular pucker.
PURPOSE: To evaluate whether oxidative tissue damage and inflammatory reactions occur in epiretinal membranes of eyes suffering from proliferative diabetic retinopathy (PDR), proliferative vitreoretinopathy (PVR), and macular pucker (MP). METHODS: Epiretinal membranes were removed during surgery and frozen at -80 degrees C (PDR, n = 26; PVR, n = 24; MP, n = 15), and oxidative tissue damage and inflammatory activity (MPO) of the membrane tissue were determined. The values are expressed as means of thiobarbituric acid-reactive substances (TBARS, nmol/mg) and MPO (units/mg). RESULTS: Both TBARS and MPO activity were significantly elevated (P < 0.05) in membranes of eyes suffering from PVR and PDR compared to MP. The myeloperoxidase activity in PDR membranes was significantly increased (P < 0.05) compared to PVR. CONCLUSIONS: Inflammatory cells and oxidative metabolites lead to oxidative reactions in PDR and PVR. The proliferation of membrane tissue may be enhanced through products of the lipoxygenase pathway, which is active in inflammatory cells and leads to oxidative tissue damage. Chemoattraction of leukocytes by oxidative metabolites renders the process self-progagating. Since patients suffering from MP have an intact vitreous body with an intact antioxidative system, this reaction occurs to a lesser degree, resulting in less membrane-growth activity. The cell-growth-enhancing properties of inflammatory cells should be further investigated in PDR and PVR with regard to new therapeutic interventions.
Cell Membrane↗
Ultrasound biomicroscopy for examination of the sclerotomy site after pars plana vitrectomy.
PURPOSE/METHODS: The pars plana sclerotomy has been considered to be a potential site for complications. Ultrasound biomicroscopy was used for in vivo examination of the entry sites in 20 eyes of 19 patients after vitrectomy. RESULTS/CONCLUSIONS: In all patients the entry sites were identified by ultrasound biomicroscopy. Extensive membranes at the sclerotomy were found in eyes treated for complications after vitrectomy. Ultrasound biomicroscopy allows in vivo examination of the pars plana sclerotomy and gives further insight into postoperative complications.
Ciliary Body↗
Bacterial growth is significantly enhanced on foldable intraocular lenses.
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Bacterial Adhesion↗