Ultrastructural and morphohistochemical study of the influence of benzalkonium chloride on human corneal limbal epithelial cells in vitro

Within the corneal limbal epithelium there exist limbal stem cells (LSC) which under suitable conditions can regenerate their population or differentiate into corneal epithelial cells. However, upon limbal damage, the cells differentiate irreversibly and do not self-renew. One of the causes of the damage of progenitor cells and their niche is a long-term use of eye drops containing preservatives. While the side effects are related to the antimicrobial activity of such eye drops, damage to cellular and cytoplasmic membranes as well as enzymatic reactions can concurrently cause disorders of normal ocular surface tissue. The aim of this study was to evaluate the toxic effects of the preservative used in eye drops – benzalkonium chloride (BAK) – on human corneal limbal epithelial cells in vitro, and to define the mechanisms of acute limbal cell damage caused by the action of BAK. Ten corneoscleras rims, which were not qualified for transplantation by the Eye Tissue Bank, were obtained from 5 deceased donors aged 39 to 43 years. The tissue fragments (explants) containing corneal limbal epithelial cells were immediately after the explantation subjected to the action of the experimental substance being benzalkonium chloride (BAK) in concentrations of 0.005% and 0.01%. The qualitative analysis of microscopic images of the corneal limbus specimens was performed on tissue sections stained with hematoxylin and eosin using the immunohistochemical method for vimentin and with the use of a transmission electron microscope. The structure of the area of corneal limbus, as well as the morphological characteristics and the ultrastructure of the very limbal cells were evaluated with careful attention to the basal epithelial cells of the limbus. The BAK-treated groups of explants in sections stained by H & E featured characteristics of severe structural disorders of the corneal limbus area. Depletion of the epithelial cells was visible and involved both superficial and deep layers. Immunohistochemical staining for vimentin did not show the expression of this protein. This might have been connected with the damage to the cytoskeleton of limbal epithelial cells and large depletion of cells reaching down to the basement membrane. The images obtained with electron microscopy demonstrate serious defects of cell ultrastructure and, indirectly, abnormal cellular metabolism, including water and electrolyte balance and energy metabolism.This experiment confirmed the significant adverse effect of benzalkonium chloride on the limbal epithelial cells and the possibility of their damage

Report from the AWA conference (23–24 February 2018, Jachranka)

Konferencja naukowa „Akademia Witrektomii Alcon” koncentruje się na nowych rozwiązaniach technologicznych i ich praktycznym wykorzystaniu w chirurgii witreoretinalnej. Jedną z najciekawszych sesji poświęcono NGENUITY® 3D Visualization System (Alcon), który dzięki zastosowaniu najbardziej zaawansowanych obecnie technologii tworzy wrażenie głębi obrazu. Ważnymi elementami konferencji były prezentacja praktycznego wykorzystania innowacyjnych rozwiązań technologicznych w leczeniu chorych oraz obszerne i owocne dyskusje.The scientific conference “Akademia Witrektomii Alcon” is the presentation of the new technological solutions and their practical use in vitreoretinal surgery. One of the most interesting session was dedicated NGENUITY® 3D Visualization System (Alcon), which through the application of the most advanced technologies, creates the impression of depth in vision. Important parts of the conference were the presentation of practical use of innovative technological solutions in patients treatments and abundant discussions

Lawn mower injuries as a cause of serious visual acuity impairment – Case reports

Objective The aim of the study is to present four cases of lawn mowers injuries as a cause of serious visual acuity impairment. Material and Methods A retrospective study of four patients admitted in 2013–2015 to the Department of Vitreoretinal Surgery in Lublin with severe open or closed globe injury, one with an intraocular foreign body (IOFB). The presence of eye protective equipment was assessed, as well as visual acuity, eye tissue condition before and after treatment, and applied therapy. Results In all cases an improvement was achieved in local conditions. The intraocular foreign body was removed, wounds sutured and damaged tissues placed in position. All eyeballs were saved. In three cases, visual acuity was improved to a usable level. Three patients underwent pars plana vitrectomy, one with IOFB removal from the vitreous cavity. Conclusions Lawn mower induced eye injuries are a significant cause of serious visual acuity impairment or blindness. The presented study shows that lawn mower eye injuries are still a therapeutic, social and economic problem, yet are very preventable with proper eye protection and patients’ education. Current prevention strategies are inadequate, and therefore should be updated

Appropriate patient estimation – clinical features improving success ratio for ocriplasmin treatment regarding Vitreomacular Interface Classification

Wprowadzenie witreolizy enzymatycznej jako metody leczenia patologii szklistkowo- plamkowych znacznie poszerzyło możliwości terapeutyczne. Nowa klasyfikacja przestrzeni witreoretinalnej (VMI) w oparciu o badanie OCT (tomografii optycznej) umożliwia precyzyjne zakwalifikowanie chorego do leczenia okryplazminą. Wskazania do tego typu leczenia obejmują: symptomatyczne przyleganie szklistkowo-plamkowe (VMA), często związane z trakcją szklistkowo-plamkową (VMT) i otworem w plamce (MH). Na podstawie dotychczasowych danych można stwierdzić, że najlepszych wyników w leczeniu VMT za pomocą okryplazminy możemy się spodziewać w przypadkach, gdy VMA nie przekracza 1500 μm, a otwór w plamce (MH) jest mniejszy niż 250 μm.Approval of ocriplasmin for the treatment of symptomatic vitreomacular adhesion widened therapeutic options. New classification of VMI based on OCT allows to precisely enroll patient for ocriplasmin treatment. Indications for treatment include: symptomatic VMA, often connected with VMT and MH. Based on multicentered clinical trial best outcome is expected in cases with VMA < 1500 μm and MH < 250 μm

Open Globe Injury (OGI) with a Presence of an Intraocular Foreign Body (IOFB)—Epidemiology, Management, and Risk Factors in Long Term Follow-Up

The purpose of the study was to evaluate visual outcomes and consider management strategies in the eyes with an intraocular foreign body (IOFB). In a single-center, retrospective case-control study, 36 eyes of 36 patients who suffered from open globe injury (OGI) with IOFB were admitted to the Department of Vitreoretinal Surgery of Medical University of Lublin, Poland from January 2015 to December 2020. Most frequent primary procedure was the pars plana vitrectomy (PPV) with IOFB removal (n = 28). Retinal detachment (RD) developed in nine eyes soon after injury or as a further complication. Recurrent retinal detachment occurred in eight of these nine cases. Final VA 0.1 or better was observed in 21 eyes (58%). Fifteen patients had BCVA of less than 0.1. One eye was not included in the final VA assessment due to the short follow-up period. In 25 out of 28 patients who underwent any kind of pars plana vitrectomy (ppV) a BCVA of <0.4 was observed. The prognosis after an IOFB injury is uncertain due to multiple factors in a peri- and postoperative period. Factors predisposing to poor visual outcomes are: IOFB localization in the posterior segment, retinal detachment, vitreous hemorrhage and prolonged silicone oil tamponade

Study of various machine learning approaches for Sentinel-2 derived bathymetry.

In recent years precise and up-to-date information regarding seabed depth has become more and more important for companies and institutions that operate on coastlines. While direct, in-situ measurements are performed regularly, they are expensive, time-consuming and impractical to be performed in short time intervals. At the same time, an ever-increasing amount of satellite imaging data becomes available. With these images, it became possible to develop bathymetry estimation algorithms that can predict seabed depth and utilize them systematically. Since there are a number of theoretical approaches, physical models, and empirical techniques to use satellite observations in order to estimate depth in the coastal zone, the presented article compares the performance and precision of the most common one to modern machine learning algorithms. More specifically, the models based on shallow neural networks, decision trees and Random Forest algorithms have been proposed, investigated and confronted with the performance of pure analytical models. The particular proposed machine learning models differ also in a set of satellite data bands used as an input as well as in applying or not geographical weighting in the learning process. The obtained results point towards the best performance of the regression tree algorithm that incorporated as inputs information about data localization, raw reflectance data from four satellite data bands and a quotient of logarithms of B2 and B3 bands. The study for the paper was performed in relatively optically difficult and spatially variant conditions of the south Baltic coastline starting at Szczecin, Poland on the west (53°26'17'' N, 14°32'32'' E) to Hel peninsula (54°43'04,3774'' N 18°37'56,9175'' E). The reference bathymetry data was acquired from Polish Marine Administration. It was obtained through profile probing with single-beam sonar or direct in-situ probing

Thermal Stability and Flammability of Styrene-Butadiene Rubber-Based (SBR) Ceramifiable Composites

Ceramifiable styrene-butadiene (SBR)-based composites containing low-softening-point-temperature glassy frit promoting ceramification, precipitated silica, one of four thermally stable refractory fillers (halloysite, calcined kaolin, mica or wollastonite) and a sulfur-based curing system were prepared. Kinetics of vulcanization and basic mechanical properties were analyzed and added as Supplementary Materials. Combustibility of the composites was measured by means of cone calorimetry. Their thermal properties were analyzed by means of thermogravimetry and specific heat capacity determination. Activation energy of thermal decomposition was calculated using the Flynn-Wall-Ozawa method. Finally, compression strength of the composites after ceramification was measured and their micromorphology was studied by scanning electron microscopy. The addition of a ceramification-facilitating system resulted in the lowering of combustibility and significant improvement of the thermal stability of the composites. Moreover, the compression strength of the mineral structure formed after ceramification is considerably high. The most promising refractory fillers for SBR-based ceramifiable composites are mica and halloysite

Scatter plot of percentage of points that acquire certain precision for given test data.

Scatter plot of percentage of points that acquire certain precision for given test data.</p

Comparison of RMSE and coefficients of determination obtained using presented models.

Comparison of RMSE and coefficients of determination obtained using presented models.</p