1,721,078 research outputs found
Effect of Various Platelet Preparations on Retinal Muller Cells
No full textPURPOSE. Peeling of the internal limiting membrane is the treatment of choice for macular holes. Fresh platelet suspension (PS) is used to support wound healing in persistent macular holes. The concentration of growth factors in fresh, frozen, and thrombin-activated PSs were compared, to optimize their trophic potential and examine their capacity to support proliferation, migration, and contraction of human retinal Muller cells. METHODS. The concentration of various growth factors in frozen PS, thrombin-activated PS, and plasma were evaluated by ELISA. The effect of these preparations on proliferation, migration, and contraction of human Muller cells were evaluated with an ATP-assay, a colony-dispersion assay, and a detached collagen gel contraction assay respectively. Plasma was tested as a control. RESULTS. Frozen and thrombin-activated PSs contained significantly more EGF, TGF-beta 1, and PDGF than did plasma. The highest concentrations of EGF and FGF were found in frozen PS. All platelet preparations and plasma supported cell growth significantly better than the control, which was serum-free culture medium. Muller cells migrated better when incubated with thrombin-activated PS than with any other test solution. Contraction was extremely strong after incubation with fresh PS compared with plasma or thrombin-activated or frozen PSs. CONCLUSIONS. Frozen and thrombin-activated PSs may be suitable alternatives to fresh PS for persisting macular holes, due to their superior effect on Muller cell migration. (Invest Ophthalmol Vis Sci. 2009; 50:4881-4886) DOI: 10.1167/iovs.08-305
Nachhaltigkeit in der Augenheilkunde
No full textThe climate crisis is threatening the health of current and future generations and represents a particular challenge for healthcare systems. To address man-made climate change, comprehensive adaptation and mitigation strategies are crucial. Medicine and ophthalmology offer various opportunities to reduce the CO2 (carbon dioxide) footprint - these should be implemented and politically encouraged. Data-driven sustainability tools may provide options to evaluate the environmental footprint and to initiate optimization strategies. Life cycle assessments are an approach to systemically measure the environmental footprint and may facilitate sustainable decisions processes. The German health system needs to develop quantifiable and holistic strategies to reduce CO2; sustainability might become a future performance indicator. This article discusses examples of adaptation to the climate crisis and mitigation in ophthalmology and beyond
Fluorophotometrische Bestimmung der Tränenfilm-Clearance und Quantifizierung der Hornhautepithelbarriere mittels konfokaler Mikroskopie
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Development of corneal in vitro models to identify wound healing and antiinflammatory effects of human serum eye drops
No full textDie vorliegende Arbeit befasst sich mit der Entwicklung cornealer In-vitro-Modelle, um die wundheilungsfördernden und antiinflammatorischen Eigenschaften humaner allogener Serumaugentropfen, einer Therapieoption bei der Keratokonjunktivitis sicca (KCS), in präklinischen Studien zu untersuchen. Im ersten Teil der Arbeit ist ein reproduzierbares Wundheilungsmodell der KCS auf Basis eines Scratch-Assays in humanen cornealen Epithelzellen (HCE-T) etabliert worden. Dabei wurde das Modell im Hinblick auf die Scratch-Erzeugung, das Coating sowie die Serumkonzentrationen optimiert. Das Modell zeigte eine geringe Intralaborvarianz. Das Wundheilungsmodell wies Unterschiede in der Wirksamkeit der Serumproben in präklinischen Untersuchungen auf. Im zweiten Teil der Arbeit wurde ein in-vivo-nahes Entzündungsmodell der KCS erfolgreich in HCE-T Zellen etabliert. Es wurde durch Zytokin-Induktion mit Interleukin-1β und Tumornekrosefaktor-α (TNF α) die Genexpression der Matrix-Metalloprotease 9 (MMP9) erhöht und durch Serumzugabe wieder reduziert. Die Induktionsbedingungen wurden in der vorliegenden Arbeit systematisch mit Design of Experiments-Studien optimiert. Auch im Entzüdnungsmodell wurde allogenes Serum in präklinischen Assays auf seine antientzündliche Wirkung untersucht. Auf Proteinebene konnte die antientzündliche Serumwirkung bestätigt werden. Auch wurde das Entzündungsmodell an dynamische Bedingungen durch Überführung in ein mikrofluidisches System angepasst. Das Modell kann die physiologische Dynamik des Tränenfilms in vitro nachstellen. Im dritten Teil der Arbeit wurde das Entzündungsmodell zu einem Kokulturmodell erweitert durch Integration der monozytischen THP-1 Zelllinie in das bereits bestehende Hemicornea-Modell. Die THP-1 Zellen zeigten im Kollagengel und in Kokultur mit humanen corenalen Keratozyten (HCK) eine gute Viabilität. Im in-vivo-näheren Kokulturmodell war die MMP9-reduzierende Wirkung des Serums ebenfalls sichtbar. Somit konnte auch dieses Modell für die präklinische Untersuchung von Serumproben eingesetzt werden. Damit wurden in der vorliegenden Arbeit corneale In-vitro-Modelle zur Untersuchung allogener Serumaugentropfen als Tierversuchsersatzmodelle entwickelt.The present work aimed at developing corneal in vitro models to analyze the wound healing and anti-inflammatory potential of human allogeneic serum eye drops, a therapy option for Dry Eye Disease (DED), in a preclinical setting. The first part of the study established a reproducible wound healing model of DED based on a scratch assay in human corneal epithelial cells (HCE-T). The model was optimized with regard to scratch generation, coating and serum concentrations. The model showed low intralaboratory variance. Further, the wound healing model demonstrated differences in the effectiveness of serum samples in preclinical studies. In the second part of the study an in-vivo-like inflammatory model of DED was successfully established in HCE-T cells. The gene expression of matrix metalloprotease 9 (MMP9) was increased by cytokine induction with interleukin-1β and tumor necrosis factor-α (TNFα) and reduced by addition of serum. The induction conditions of the inflammatory model were systematically optimized using Design of Experiments. Allogeneic serum eye drops were examined for their anti-inflammatory effect in preclinical assays in the inflammatory model. The anti-inflammatory serum effect was confirmed at protein level. The inflammatory model was adapted to dynamic conditions by transferring it to a microfluidic system. The model can simulate the physiological dynamics of the tear film. In the third section, the inflammatory model was developed to a co-culture model by integrating the monocytic THP-1 cell line into the existing hemicornea model. The THP-1 cells showed good viability in the collagen gel and in coculture with human corneal keratocytes (HCK). The MMP9-reducing effect of the serum was visible in the in-vivo-like co-culture model. Hence, this model could also be used for the preclinical examination of serum samples. In summary, the present work developed corneal in vitro models to analyze allogeneic serum eye drops without the use of animal experiments
Quantifizierung und Lokalisation von Matrixmetalloproteinasen und TIMP-1 in Tränen, Blut und ulzeriertem Hornhautgewebe bei rheumatoider Arthritis
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