47 research outputs found
Complications After Anti-VEGF Therapy in Patients with Wet Form of AMD
Anti-VEGF therapy is the main treatment in patients with the wet form of AMD. Although successful in most cases, prolonged use of intravitreal therapy can lead to serious complications. The aim of this study is to present the possible longterm complications of anti-VEGF therapy in patients with the wet form of AMD, as well as the ways to prevent them. Methods: In our study, we included 32 patients with a wet form of AMD. They were all examined ophthalmologically in detail for VA, fundus color photography, OCT (Revue, Optovue) and OCT-A (Angiophlex, Zeiss). All patients were treated with aflibercept (Eylea) - according to the Treat and Extend scheme for a period of 2 years. They were followed for complications for a period of 2 years. Results: In the long run we observed the following complications expressed in %: tachyphylaxis to the drug substance – 20%; tears of RPE-10%; fibrosis and scarring - 45%; retinal atrophy 25%. In 20% of the observed patients we found tachyphylaxis after the first year, which led to a decrease in the effectiveness of treatment. In 10% of cases we observed rupture of RPE. This occurred mainly in patients with previous detachment of RPE with a large area and height. Retinal fibrosis developed in patients with macular hemorrhage, low VA, refractory retinal cysts, or cases of RAP. Retinal fibrosis usually appeared after 10 injections. These are patients with low initial visual acuity, thin choroid especially subfoveolar and usually occurred after a small number of intravitreal injections. Conclusion: Complications after anti-VEGF therapy are relatively rare, but always associated with very serious visual impairment. The stronger the effect of the anti-VEGF drug, the more common the complications, especially retinal fibrosis. Early detection of risk factors such as low initial vision, refractory retinal cysts, macular hemorrhage, large neovascular membrane, are a prerequisite for successful prevention and treatment of these complications
Comparative Analysis Of The Results Of Anti-VEGF Therapy In Patients With AMD
Intravitreal injections are one of the most common procedures in ophthalmology. It is connected with direct delivery of drugs in the vitreous body. The aim of our survey is to show our comparative analysis of the results in the treatment of AMD patients with Lucentis and Eylea. Material and methods: We enrolled 24 patients with wet AMD, diagnosed and treated in the ophthalmic department of MMA for a period of 2 years. In 7 of the patients we used Lucentis and in the rest 17 Eylea. All patients were examined for VA, OCT central retinal thickness and FA (Topcon 3D OCT – FA +). The patients were treated according to the Treat and extend protocol with period of extension of 2 weeks. Results: Our results point out that patients treated with Lucentis had an increase of the VA with two lines. They had also a reduction of retinal thickness. In RAP patients Lucentis gave better results than other medications. The Eylea treated patients showed also improvement of the VA, which was more significant than in the previous group. The decrease in the CRT was from approximately 400±130 μm to 288±74 μm in the 6-month follow up. Conclusion: Our survey points out that both Lucentis and Eylea are effective in the treatment of AMD, although aflibercept shows slightly better results in terms of VA and CRT. The treatment of this multifactorial disease is complex and has to be individualized in order to meet the specific needs of the patients. We have to adjust the treatment in each case to be maximum effective
The State and Moods of Civil Society on the Example of a Sociological Study of Public Organizations
The article presents the results of a study of the state and mood of civil society from the standpoint of a political and sociological approach. The definition of the state of civil society, its features and components is proposed. The complexity and inconsistency of attitudes among young people as a reference group is analyzed.The study also compared some indicators with previous similar studies and some dynamics of the state of the reference group in connection with the conduct of ITS. The competitive parameters that have received dynamics and their connection with the general mood in the youth environment are determined.The study was conducted in order to identify the parameters of subjects exclusively within the framework of civil society and did not consider the marginalizing component and processes outside civil society.For further research, a reference group is provided with a description of the properties of the group and parameters for segmentation and identification of related processes
Causative factors for hyperopia regression in excimer keratorefractive surgery
Регресът и хипокорекцията са специфични усложнения в кераторефрактивната хирургия, които трудно се диференцират, пряко зависят от роговичната биомеханика и обуславят икономически значима тенденция към повторна корекция. Научен интерес буди въпросът кои са и от какво естество са факторите, предразполагащи към неочаквани или нетрайни рефрактивни резултати. Не по-малко важен въпрос е дали регресът е хирургична усложнение или само проблем на селекцията на пациенти, на избора на неподходяща процедура или на лазерна платформа. Настоящото изследване предлага напълно нов подход в измерването на регpеса, както и статистически обосновани резултати по отношение на възможните причини за него.Regression and hypocorrection are specific complications in refractive surgery that frequently lead to unexpected or perishable refractive results. They develop due to unforeseen alteration in corneal biomechanics and are hard to differentiate and presume. Their ethiology and pathogenesis are still vague and no statistical evidence on predisposing factors is present. Once more familiar, the regression might be controlled by patient selection, procedure planning or laser platform opting. This study offers a completely new approach to the measurement of regression and statistically sound results in terms of the possible reasons and biomarkers
Экспериментальная оценка состязательных атак на глубокие нейронные сети при решении задач распознавания медицинских изображений
This paper addresses the problem of dependence of the success rate of adversarial attacks to the deep neural networks on the biomedical image type and control parameters of generation of adversarial examples. With this work we are going to contribute towards accumulation of experimental results on adversarial attacks for the community dealing with biomedical images. The white-box Projected Gradient Descent attacks were examined based on 8 classification tasks and 13 image datasets containing more than 900 000 chest X-ray and histology images of malignant tumors. An increase of the amplitude and the number of iterations of adversarial perturbations in generating malicious adversarial images leads to a growth of the fraction of successful attacks for the majority of image types examined in this study. Histology images tend to be less sensitive to the growth of amplitude of adversarial perturbations. It was found that the success of attacks was dropping dramatically when the original confidence of predicting image class exceeded 0,95.Исследуются обнаруженные несколько лет назад проблемы уязвимости глубоких нейронных сетей к так называемым состязательным атакам, которые заставляют сеть принимать ошибочные классификационные решения. Состязательные атаки осуществляются с помощью «атакующих» изображений – незначительно модифицированных версий исходных. Целью работы является изучение зависимости успеха состязательных атак от типа распознаваемых биомедицинских изображений и значений управляющих параметров алгоритмов генерации их атакующих версий. Экспериментальные исследования проводились на примере решения восьми типичных задач медицинской диагностики с использованием глубокой нейронной сети InceptionV3, а также 13 наборов, содержащих более чем 900 000 рентгеновских изображений грудной клетки и гистологических изображений злокачественных опухолей. С увеличением амплитуды вредоносного возмущения и количества итераций генерации зловредного шума вероятность ошибки классификации растет. В то же время различные типы изображений демонстрируют разную чувствительность к данном параметрам. Изображения, которые изначально классифицировались сетью с уверенностью более 95 %, гораздо более устойчивы к атакам. Нейронные сети, обученные для классификации гистологических изображений, оказались более устойчивы к состязательным атакам нежели сети, обученные для классификации рентгеновских изображений
Компьютеризированная диагностика рака простаты на основе полнослайдовых гистологических изображений и методов глубокого обучения
This paper presents the results of an experimental study and the development of tools for automatic analysis and recognition of histological images in order to obtain quantitative estimates of the presence and degree of aggressiveness of prostate cancer in the commonly used Gleason and ISUP scales. The input data consisted of 10 616 whole-slide histological images with the size of the largest side up to 100 000 pixels and22 089 of their image tiles of 256×256 pixels in size. Two solutions were chosen as the final ones. The first solution is based on sequential analysis of image fragments and includes feature extraction using the ResNet50 network and the subsequent generalization of particular recognition results using a small convolutional network. The second solution is based on the simultaneous analysis of the selected informative sections, presented in the form of an intermediate pseudo-image, and its subsequent recognition using an ensemble of four variants of convolutional networks with the EfficientNetB0 architecture. Being independently tested on an unknown image dataset that was not available for authors, these approaches achieved the prediction accuracy of 0,9277 according to the ISUP scale.Представлены результаты экспериментальных исследований и разработки средств автоматического анализа и распознавания гистологических изображений с целью получения количественных оценок наличия и степени агрессивности рака простаты в общепринятых шкалах Глисона и ISUP. В качестве исходных данных использовались 10 616 полнослайдовых гистологических изображений с размером большей стороны до 100 000 пикселов и 22 089 их фрагментов размером 256×256 пикселов. Проведена оценка эффективности решения задачи с применением как традиционных методов, так и методов глубокого обучения. В качестве финальных выбраны два решения. Первое решение основано на последовательном анализе фрагментов изображений и включает выделение признаков с использованием сети ResNet50 и последующим обобщением частных результатов распознавания с помощью небольшой сверточной сети. Второе решение базируется на одновременном анализе отобранных информативных участков, представленных в виде промежуточного псевдоизображения, и последующем его распознавании с использованием ансамбля из четырех вариантов сверточных сетей с архитектурой EfficientNetB0. В результате независимого тестирования на закрытом наборе изображений, недоступных авторам, достигнута точность предсказания финальной оценки по шкале ISUP, равная 0,9277
INVESTIGATION OF THE DOSE DEPENDENCE OF DETECTORS BASED ON Аl2O3
Thermostimulated luminescence occurs when a solid is heated, which is previously irradiated by ionizing radiation. Dose limit is proportional to the maximum number of electrons captured by detector traps. Thermooptical processing allows to change concentration of oxygen vacancies
Genome Instability and Transcription Elongation Impairment in Human Cells Depleted of THO/TREX
THO/TREX connects transcription with genome integrity in yeast, but a role of mammalian THO in these processes is uncertain, which suggests a differential implication of mRNP biogenesis factors in genome integrity in yeast and humans. We show that human THO depletion impairs transcription elongation and mRNA export and increases instability associated with DNA breaks, leading to hyper-recombination and γH2AX and 53BP1 foci accumulation. This is accompanied by replication alteration as determined by DNA combing. Genome instability is R-loop–dependent, as deduced from the ability of the AID enzyme to increase DNA damage and of RNaseH to reduce it, or from the enhancement of R-loop–dependent class-switching caused by THOC1-depletion in CH12 murine cells. Therefore, mammalian THO prevents R-loop formation and has a role in genome dynamics and function consistent with an evolutionary conservation of the functional connection between these mRNP biogenesis factors and genome integrity that had not been anticipated
Radiotherapeutic alternatives for previously irradiated recurrent gliomas
Re-irradiation for recurrent gliomas has been discussed controversially in the past. This was mainly due to only marginal palliation while being associated with a high risk for side effects using conventional radiotherapy
Tailor-Made Zinc-Finger Transcription Factors Activate FLO11 Gene Expression with Phenotypic Consequences in the Yeast Saccharomyces cerevisiae
Cys2His2 zinc fingers are eukaryotic DNA-binding motifs, capable of distinguishing different DNA sequences, and are suitable for engineering artificial transcription factors. In this work, we used the budding yeast Saccharomyces cerevisiae to study the ability of tailor-made zinc finger proteins to activate the expression of the FLO11 gene, with phenotypic consequences. Two three-finger peptides were identified, recognizing sites from the 5′ UTR of the FLO11 gene with nanomolar DNA-binding affinity. The three-finger domains and their combined six-finger motif, recognizing an 18-bp site, were fused to the activation domain of VP16 or VP64. These transcription factor constructs retained their DNA-binding ability, with the six-finger ones being the highest in affinity. However, when expressed in haploid yeast cells, only one three-finger recombinant transcription factor was able to activate the expression of FLO11 efficiently. Unlike in the wild-type, cells with such transcriptional activation displayed invasive growth and biofilm formation, without any requirement for glucose depletion. The VP16 and VP64 domains appeared to act equally well in the activation of FLO11 expression, with comparable effects in phenotypic alteration. We conclude that the functional activity of tailor-made transcription factors in cells is not easily predicted by the in vitro DNA-binding activity