Pre-hyperglycemia immune cell trafficking underlies subclinical diabetic cataractogenesis.

BACKGROUND: This work elucidates the first cellular and molecular causes of cataractogenesis. Current paradigm presupposes elevated blood glucose as a prerequisite in diabetic cataractogenesis. Novel evidence in our model of diabetic cataract challenges this notion and introduces immune cell migration to the lens and epithelial-mesenchymal transformation (EMT) of lens epithelial cells (LECs) as underlying causes. METHODS: Paucity of suitable animal models has hampered mechanistic studies of diabetic cataract, as most studies were traditionally carried out in acutely induced hyperglycemic animals. We introduced diabetic cataract in the Nile grass rat (NGR) that spontaneously develops type 2 diabetes (T2D) and showed its closeness to the human condition. Specialized stereo microscopy with dual bright-field illumination revealed novel hyperreflective dot-like microlesions in the inner cortical regions of the lens. To study immune cell migration to the lens, we developed a unique in situ microscopy technique of the inner eye globe in combination with immunohistochemistry. RESULTS: Contrary to the existing paradigm, in about half of the animals, the newly introduced hyper reflective dot-like microlesions preceded hyperglycemia. Even though the animals were normoglycemic, we found significant changes in their oral glucose tolerance test (OGTT), indicative of the prediabetic stage. The microlesions were accompanied with significant immune cell migration from the ciliary bodies to the lens, as revealed in our novel in situ microscopy technique. Immune cells adhered to the lens surface, some traversed the lens capsule, and colocalized with apoptotic nuclei of the lens epithelial cells (LECs). Extracellular degradations, amorphous material accumulations, and changes in E-cadherin expressions showed epithelial-mesenchymal transformation (EMT) in LECs. Subsequently, lens fiber disintegration and cataract progression extended into cortical, posterior, and anterior subcapsular cataracts. CONCLUSIONS: Our results establish a novel role for immune cells in LEC transformation and death. The fact that cataract formation precedes hyperglycemia challenges the prevailing paradigm that glucose initiates or is necessary for initiation of the pathogenesis. Novel evidence shows that molecular and cellular complications of diabetes start during the prediabetic state. These results have foreseeable ramifications for early diagnosis, prevention and development of new treatment strategies in patients with diabetes.

[Association, expectations and barriers of the use of exoskeletons in small and medium-sized enterprises]. / Assoziation, Erwartungen und Barrieren eines Exoskeletteinsatzes in kleinen mittelständischen Unternehmen.

Background: In the manufacturing industry, work-related musculoskeletal disorders (MSD) result in sick days and have substantial economic consequences for the enterprise and the national economy. Exoskeletons can support the body when handling heavy loads and enduring enforced postures. Exoskeletons are being piloted particularly in large companies in the automotive industry; however, exoskeletons have so far attracted little interest in small and medium-sized enterprises (SME) and their use has so far barely been scientifically examined. The aim of this work was to determine barriers to exoskeleton implementation and expectations for their use in the manufacturing sector. Method: Semi-structured guided interviews in six manufacturing companies were carried out and analyzed. Results: In the enterprises a variety of activities up to the loading limits are carried out. Exoskeletons are generally expected to facilitate work and provide economic advantages. There are concerns with respect to their use due to cost factors, uncertain benefits and wearing discomfort. Particularly uncertainties about the effects of exoskeletons become evident. Conclusion: The presented interview results are one step in an interdisciplinary process of further developing and implementing exoskeletons in the manufacturing industry. Concerns and unawareness of potential enterprises and users must be addressed, also to achieve a high user acceptance. Further studies that survey the identification of needs with better discriminatory power could provide additional insights.

In vivo imaging with a fundus camera in a rat model of laser-induced choroidal neovascularization.

PURPOSE: To investigate the use of imaging and quantitative measurement capabilities of a modified fundus camera in a rat model of laser-induced choroidal neovascularization. METHODS: Following induction of experimental choroidal neovascularization, Dark Agouti rats underwent serial in vivo imaging with a fundus camera (FF450plus, Carl Zeiss MediTec, Jena, Germany), including color, reflectance and fluorescence imaging. RESULTS: A custom-made setting allowed high-resolution imaging. Change of fluorescence intensity following intravenous or intravitreal dye injection could be quantitatively monitored over time. Hardware binning resulted in an improved signal-to-noise ratio and a reduction of flash light intensity. Simultaneous fluorescence imaging following injection of two different dendritic polygylcerol sulfate dyes could be demonstrated. CONCLUSION: This study demonstrates the use and optimizations of a fundus camera for various in vivo imaging modalities in rats. Molecular imaging of the eye may allow for better insights into cellular dysfunction and optimization of therapeutic strategies.

Spatial correlation of 2D hard-tissue histology with 3D microCT scans through 3D printed phantoms.

Hard-tissue histology-the analysis of thin two-dimensional (2D) sections-is hampered by the opaque nature of most biological specimens, especially bone. Therefore, the cutting process cannot be assigned to regions of interest. In addition, the applied cutting-grinding method is characterized by significant material loss. As a result, relevant structures might be missed or destroyed, and 3D features can hardly be evaluated. Here, we present a novel workflow, based on conventual microCT scans of the specimen prior to the cutting process, to be used for the analysis of 3D structural features and for directing the sectioning process to the regions of interest. 3D printed fiducial markers, embedded together with the specimen in resin, are utilized to retrospectively register the obtained 2D histological images into the 3D anatomical context. This not only allows to identify the cutting position, but also enables the co-registration of the cell and extracellular matrix morphological analysis to local 3D information obtained from the microCT data. We have successfully applied our new approach to assess hard-tissue specimens of different species. After matching the predicted microCT cut plane with the histology image, we validated a high accuracy of the registration process by computing quality measures namely Jaccard and Dice similarity coefficients achieving an average score of 0.90 ± 0.04 and 0.95 ± 0.02, respectively. Thus, we believe that the novel, easy to implement correlative imaging approach holds great potential for improving the reliability and diagnostic power of classical hard-tissue histology.

Current Approaches for Image Fusion of Histological Data with Computed Tomography and Magnetic Resonance Imaging.

Classical analysis of biological samples requires the destruction of the tissue's integrity by cutting or grinding it down to thin slices for (Immuno)-histochemical staining and microscopic analysis. Despite high specificity, encoded in the stained 2D section of the whole tissue, the structural information, especially 3D information, is limited. Computed tomography (CT) or magnetic resonance imaging (MRI) scans performed prior to sectioning in combination with image registration algorithms provide an opportunity to regain access to morphological characteristics as well as to relate histological findings to the 3D structure of the local tissue environment. This review provides a summary of prevalent literature addressing the problem of multimodal coregistration of hard- and soft-tissue in microscopy and tomography. Grouped according to the complexity of the dimensions, including image-to-volume (2D ⟶ 3D), image-to-image (2D ⟶ 2D), and volume-to-volume (3D ⟶ 3D), selected currently applied approaches are investigated by comparing the method accuracy with respect to the limiting resolution of the tomography. Correlation of multimodal imaging could position itself as a useful tool allowing for precise histological diagnostic and allow the a priori planning of tissue extraction like biopsies.

Atomic-resolution mapping of transcription factor-DNA interactions by femtosecond laser crosslinking and mass spectrometry.

Transcription factors (TFs) regulate target genes by specific interactions with DNA sequences. Detecting and understanding these interactions at the molecular level is of fundamental importance in biological and clinical contexts. Crosslinking mass spectrometry is a powerful tool to assist the structure prediction of protein complexes but has been limited to the study of protein-protein and protein-RNA interactions. Here, we present a femtosecond laser-induced crosslinking mass spectrometry (fliX-MS) workflow, which allows the mapping of protein-DNA contacts at single nucleotide and up to single amino acid resolution. Applied to recombinant histone octamers, NF1, and TBP in complex with DNA, our method is highly specific for the mapping of DNA binding domains. Identified crosslinks are in close agreement with previous biochemical data on DNA binding and mostly fit known complex structures. Applying fliX-MS to cells identifies several bona fide crosslinks on DNA binding domains, paving the way for future large scale ex vivo experiments.

Effect of a suction device for femtosecond laser on anterior chamber depth and crystalline lens position measured by OCT.

PURPOSE: To investigate the position and stability of the crystalline lens after application of a suction device containing a contact lens and a vacuum unit for the treatment of presbyopia using a femtosecond laser. METHODS: Twenty presbyopic (44.4+/-4.3 years) and 5 pre-presbyopic patients (31.6+/-3.8 years) were included. The anterior chamber depth, along with the position of the lens, was investigated before and after application of the suction device with optical coherence tomography (Visante OCT; Carl Zeiss Meditec AG). The type of suction device is routinely used for femtosecond LASIK with the VisuMax laser (Carl Zeiss Meditec AG). RESULTS: In both groups, there was a reduction in anterior chamber depth of approximately 700 microm due to the suction device, and the anterior chamber depth achieved was stable. The maximum variation was 160 microm. At the periphery of the crystalline lens, there were movements up to 310 microm axially and 470 microm laterally. CONCLUSIONS: The study proves that once the suction device has been applied, the crystalline lens is stable enough to undergo presbyopic laser therapy. However, the reduction in anterior chamber depth induced by the suction device showed significant individual variation. The exact position of the lens should therefore be measured immediately before laser surgery.

Lipid Emulsion-Based OCT Angiography for Ex Vivo Imaging of the Aqueous Outflow Tract.

Purpose: Contrast agents applicable for optical coherence tomography (OCT) imaging are rare. The intrascleral aqueous drainage system would be a potential application for a contrast agent, because the aqueous veins are of small diameter and located deep inside the highly scattering sclera. We tested lipid emulsions (LEs) as candidate OCT contrast agents in vitro and ex vivo, including milk and the anesthetic substance Propofol. Methods: Commercial OCT and OCT angiography (OCTA) devices were used. Maximum reflectivity and signal transmission of LE were determined in tube phantoms. Absorption spectra and light scattering was analyzed. The anterior chamber of enucleated porcine eyes was perfused with LEs, and OCTA imaging of the LEs drained via the aqueous outflow tract was performed. Results: All LEs showed a significantly higher reflectivity than water (P < 0.001). Higher milk lipid content was positively correlated with maximum reflectivity and negatively with signal transmission. Propofol exhibited the best overall performance. Due to a high degree of signal fluctuation, OCTA could be applied for detection of LE. Compared with blood, the OCTA signal of Propofol was significantly stronger (P = 0.001). As a proof of concept, time-resolved aqueous angiography of porcine eyes was performed. The three-dimensional (3D) structure and dynamics of the aqueous outflow were significantly different from humans. Conclusions: LEs induced a strong signal in OCT and OCTA. LE-based OCTA allowed the ability to obtain time-resolved 3D datasets of aqueous outflow. Possible interactions of LE with inner eye's structures need to be further investigated before in vivo application.

First efficacy and safety study of femtosecond lenticule extraction for the correction of myopia: six-month results.

PURPOSE: To prospectively study the feasibility of femtosecond lenticule extraction (FLE), a new method of refractive correction. SETTING: Department of Ophthalmology, Philipps University of Marburg and Helios Clinic, Erfurt, Germany. METHODS: A flap and a lenticule of intrastromal corneal tissue were simultaneously cut with a VisuMax femtosecond laser system. Next, the lenticule was manually removed and the flap repositioned. The target refraction in all cases was -0.75 diopter (D). RESULTS: All 10 myopic eyes in the initial treatment group completed the final 6-month follow-up. The mean patient age was 39 years. The mean spherical equivalent (SE) was -4.73 +/- 1.48 (SD) preoperatively and -0.33 +/- 0.61 D 6 months postoperatively. Ninety percent of eyes were within +/-1.00 D and 40% were within +/-0.50 D of the intended correction. No eye lost 2 or more Snellen lines. Corneal topography showed large, prolate optical zones. Aberrometry showed no significant induction of higher-order aberrations. On a standardized questionnaire, all patients said they were very satisfied with the results. CONCLUSIONS: Preliminary results indicate that FLEx [corrected] is a promising new corneal refractive procedure to correct myopia.

Automated Retinal Image Analysis for Evaluation of Focal Hyperpigmentary Changes in Intermediate Age-Related Macular Degeneration.

PURPOSE: To develop and evaluate a software tool for automated detection of focal hyperpigmentary changes (FHC) in eyes with intermediate age-related macular degeneration (AMD). METHODS: Color fundus (CFP) and autofluorescence (AF) photographs of 33 eyes with FHC of 28 AMD patients (mean age 71 years) from the prospective longitudinal natural history MODIAMD-study were included. Fully automated to semiautomated registration of baseline to corresponding follow-up images was evaluated. Following the manual circumscription of individual FHC (four different readings by two readers), a machine-learning algorithm was evaluated for automatic FHC detection. RESULTS: The overall pixel distance error for the semiautomated (CFP follow-up to CFP baseline: median 5.7; CFP to AF images from the same visit: median 6.5) was larger as compared for the automated image registration (4.5 and 5.7; P < 0.001 and P < 0.001). The total number of manually circumscribed objects and the corresponding total size varied between 637 to 1163 and 520,848 pixels to 924,860 pixels, respectively. Performance of the learning algorithms showed a sensitivity of 96% at a specificity level of 98% using information from both CFP and AF images and defining small areas of FHC ("speckle appearance") as "neutral." CONCLUSIONS: FHC as a high-risk feature for progression of AMD to late stages can be automatically assessed at different time points with similar sensitivity and specificity as compared to manual outlining. Upon further development of the research prototype, this approach may be useful both in natural history and interventional large-scale studies for a more refined classification and risk assessment of eyes with intermediate AMD. TRANSLATIONAL RELEVANCE: Automated FHC detection opens the door for a more refined and detailed classification and risk assessment of eyes with intermediate AMD in both natural history and future interventional studies.

Vector analysis of myopic astigmatism corrected by femtosecond refractive lenticule extraction.

PURPOSE: To evaluate the visual outcome of refractive lenticule extraction in eyes with myopic astigmatism using the Visumax femtosecond laser. SETTING: Department of Ophthalmology, HELIOS Klinikum Erfurt, Erfurt, Germany. DESIGN: Nonrandomized clinical trials. METHODS: The data set encompassed treatments of sphere and astigmatism. Vector analysis was performed to study the astigmatic results at each follow-up visit at 1 week and 1, 3, and 6 months. Visual outcomes were analyzed for the 6-month follow-up period. RESULTS: The data evaluated was a complete set of refractive data of 182 treatments (87 left eyes, 95 right eyes). Efficacy, predictability, and safety with regard to astigmatic correction were comparable to the results with U.S. Food and Drug Administration-approved excimer lasers. At 6 months, the mean error ratio was 0.68 ± 0.75 (SD) and the mean correction ratio was 1.11 ± 0.69. There was slight astigmatic undercorrection (approximately 10%) over time. The residuum of the linear regression analysis of the predictability plot was approximately 0.4 diopter. Ninety-six percent of the eyes had a corrected distance visual acuity (CDVA) of 20/20 or better; no eye had a CDVA worse than 20/32. CONCLUSION: Femtosecond refractive lenticule extraction is an effective procedure for correcting myopic astigmatism.