Relentless placoid chorioretinitis - A case report

© 2016, Serbia Medical Society. All rights reserved. Introduction Relentless placoid chorioretinitis is an entity which belongs to the group of an atypical intermediate form of primary inflammatory choriocapillaropathies, resembling both acute posterior multifocal placoid pigment epitheliopathy and serpiginous choroiditis, but the retinal distribution and clinical course are not the same. Because of this similarity this entity was termed AMPPiginous. This entity was first described by Jones et al. in 2000. The aim of our case report is to present a very specific case where the clinical course was progressive, with loss of vision in the affected eye. Case Outline A 31-year-old man, with no previous ophthalmic diseases, was hospitalized at the Clinic of Ophthalmology, Clinical Center Kragujevac, because of a reduction of vision in the right eye, and scotoma and metamorphopsia in the left eye. The clinical course of retinal lesions in the left eye resembled the changes observed in acute posterior multifocal placoid pigment epitheliopathy, and the right eye changes were between acute posterior multifocal placoid pigment epitheliopathy and serpiginous choroiditis. The diagnosis of relentless placoid chorioretinitis was confirmed after clinical, laboratory, immunological, virological, and angiography examinations. Conclusion The progressive clinical course of the disease, complemented by multimodal imaging and extensive laboratory diagnostics, has led us to the diagnosis of relentless placoid chorioretinitis. The combined anti-inflammatory and immunomodulatory therapy led to the stabilization of visual acuity of the left eye as opposed to the right, where there has been no recovery

Environmentally friendly method for S, N functionalization of graphene quantum dots

Graphene quantum dots (GQDs) show exceptional optical and physical properties. To enable their wider application and improve their optical properties, it is usually necessary to modify them with different functional groups and heteroatoms. Toxic reagents that are potentially harmful to human health and the environment are often used for these procedures. One of the methods that have been successfully used is gamma radiation. In this study, gamma irradiation was employed to achieve structural modification of GQDs without the usage of reactive, toxic chemicals. In this way, an eco-friendly and simple procedure for the incorporation of S and N atoms into the GQDs structure is developed

Two cases of uveitis masquerade syndrome caused by bilateral intraocular large B-cell lymphoma

Introduction. Sometimes it is not easy to clinically recognize subtle differences between intraocular lymphoma and non-infectious uveitis. The most common lymphoma subtype involving the eye is B-cell lymphoma. Case report. We presented two patients aged 59 and 58 years with infiltration of the subretinal space with a large B-cell non-Hodgkin intraocular lymphoma. The patients originally had clinically masked syndrome in the form of intermediate uveitis. As it was a corticosteroid-resistant uveitis, we focused on the possible diagnosis of neoplastic causes of this syndrome. During hospitalization, the neurological symptoms emerged and multiple subretinal changes accompanied by yellowish white patches of retinal pigment epithelium with signs of vitritis, which made us suspect the intraocular lymphoma. Endocra-nial magnetic resonance imaging established tumorous infiltration in the region of the left hemisphere of the cerebellum. The histopathological finding confirmed the diagnosis of large B-cell non-Hodgkin lymphoma of risk moderate degree, immunoblast - centroblast cytological type. The other patient had clinical chronic uveitis accompanied by yellowish shaped white echographic changes of the retina and localized changes in the level of the subretina. The diagnosis of lymphoma was made by brain biopsy. Conclusion. Uveitis masquerade syndrome should be considered in all patients over 40 years with idiopathic steroid-resistant uveitis. Treatment begun on time can affect the course and improve the prognosis of uveitis masquerade syndrome (UMS) and systemic disease

The impact of silicone hydrogel contact lenses on the measurement of intraocular pressure using non-contact tonometry

© 2017, Institut za Vojnomedicinske Naucne Informacije/Documentaciju. All rights reserved. Background/Aim. Measurement of intraocular pressure (IOP) over therapeutic silicone hydrogel soft contact lenses by a non-contact method of tonometry could be applied in opthalmologic practice but the results obtained are still controversial. The aim of this study was to evaluate the effect of spherically designed silicone hydrogel soft contact lenses and their power on values of IOP measured by using a non-contact tonometry method. Methods. We measured IOP with and without spherical silicone hydrogel soft contact lenses on 143 eyes of 80 subjects who did not have any ocular or systemic diseases. Results. The Wilcoxon statistical analysis test for ranking average values of IOP measured on 143 eyes over a spherical silicone hydrogel soft contact lenses showed significantly higher values compared to those measured with no contact lenses (15.81 ± 3.46 mm Hg vs 14.54 ± 3.19 mm Hg; respectively; Z = -5.224, p = 0.001). Refractive power analysis of the contact lenses of -9.00D to +6.00 D showed a significant difference of IOP in the range from 0.00D to -6.00D. Conclusion. Non-contact tonometry is not an accurate method of IOP measuring over spherical silicone hydrogel soft contact lenses which belong to therapeutic contact lenses

N-doped graphene quantum dots for detection of palladium(II) ions and carbofuran

We produced Graphene Quantum Dots (GQDs) by electrochemical oxidation of graphite rods and exposed them to gamma irradiation at a dose of 200 kGy, in the presence of ethylenediamine. Before irradiation, oxygen was removed from the GQDs dispersion by purging with Ar. These conditions induced both chemical reduction as well as the incorporation of N atoms in the structure of GQDs. Thus, N-doped GQDs were produced. The morphology of dots was investigated using atomic force microscopy. UV-Vis and photoluminescence spectroscopy were used to investigate the optical properties of modified GQDs. The changes in the intensities of PL emission spectra were studied in the presence of different concentrations of Pd2+ and pesticide carbofuran. We observed promising results for the application of N-doped GQDs for non-enzymatic PL detection of selected metal ions and molecules of pesticide

Application of graphene quantum dots in heavy metals and pesticides detection

Graphene Quantum Dots (GQDs) were produced using electrochemical oxidation of graphite rods. Obtained GQDs were gamma-irradiated in the presence of the N atoms source, ethylenediamine. Both structural and morphological changes were investigated using UV-Vis, X-ray photoelectron and photoluminescence (PL) spectroscopy as well as atomic force microscopy. The ability of both types of dots to change PL intensity in the presence of pesticides such as malathion and glyphosate, as well as copper (II) ions was detected. These preliminary results indicated a high potential of produced GQDs to be applied as non-enzymatic PL sensors for the detection of selected pesticides and metal ions

Gamma irradiation as a tool for modification of graphene oxide-silver nanowires composites

Graphene oxide (GO) was produced using the Hummers' method while silver nanowires (AgNWs) were obtained by polyol synthesis. Composite was produced by simple mixing of GO and AgNWs dispersions. The composite was produced in a form of free/standing films by vacuum filtration and exposed to gamma irradiation in an oxygen-free atmosphere. After irradiation, without any additional cleaning, the structure, morphology and electrical properties were investigated. Gamma irradiation was shown to be an efficient tool to induce a chemical reduction of GO, and it was able to improve the electrical conductivity of produced composites. Due to avoiding the usage of reagents and solvents, this method belongs to green chemical approaches

Amino functionalized graphene quantum dots - new fluorescent sensor for Co2+ ions

Graphene quantum dots (GQDs) were fabricated by simple electrochemical oxidation of graphite electrodes. Modified GQDs were obtained by gamma irradiation of GQDs, EDA, and IPA mixture at a dose of 25 kGy. In this approach, GQDs with the amino groups were produced (25γ-GQDs). These GQDs have shown a high uniformity, good dispersibility in water, and strong photoluminescence in the blue part of the electromagnetic spectrum. Modified GQDs were studied in the optical detection of Co2+ ions. The PL intensities of GQDs were measured in the presence of Co2+ ions in the concentration range 0-7.5 µmol L-1 . It was demonstrated that PL intensities decreased linearly in the concentration range 0-2.5 µmol L-1 . The value of the coefficient of determination (R2= 0.95949) indicates the potential of 25γ-GQDs for application in optical sensing of Co2+ ions

The mechanism behind Pd(II) and carbofuran-induced change of graphene quantum dots photoluminescence intensity

The increasing presence of pesticides and heavy metals in the environment and their negative impact on human, animal, and plant health, demand green, low-cost, and simple methods for their monitoring. Due to photoluminescence (PL) in the visible part of the spectrum, biocompatibility, and ecological acceptability, graphene quantum dots (GQDs) are at the center of attention in the field of optical sensing. GQDs show great potential as PL sensors for Pd(II) ions and insecticide carbofuran. In this work, FTIR spectroscopy and Density Functional Theory (DFT) calculation were used to resolve the mechanism of PL change in the presence of these analytes

Graphene oxide-silver nanowires composites for protection against modern pollution - electromagnetic waves

With the development of the electronic industry, telecommunication, transportation, energy storage devices, and wireless technologies, the need for materials that are able to block electromagnetic waves (EMWs) in low-frequency regions of the spectrum is increasing. A new type of pollution named pollution by EMWs is an inevitable component of modern life. Although materials efficient in blocking the propagation of EMWs are developed, these materials show drawbacks regarding durability and mechanical properties, as well as a high production price and processability. Thus, new eco-friendly and durable materials are needed. Herein, we produced composites based on graphene oxide and silver nanowires to create an efficient shielding barrier for low frequencies (0-15 GHz) EMWs