In Vitro Cytotoxicity of CdSe/ZnS Quantum Dots and Their Interaction with Biological Systems

Semiconductor nanocrystals (quantum dots, QDs) have a wide range of potential application in multiplexed tissue and cell imaging, and for in vivo molecular diagnostics and therapy. Therefore studying of the toxicity of QDs and their influence on various cellular processes in vitro is necessary to understand their interaction with living systems.; The paper presents the results of studies on the evaluation of CdSe/ZnS QD cytotoxicity, as well as the results of studying their interaction with freshly prepared human monocytes in vitro. Keywords: Quantum dots, semiconductor nanocrystals, cytotoxicity, in vitro models, monocytes

Cytotoxicity of Polyelectrolyte Microcapsules Encoded with Semiconductor Nanocrystals

Polyelectrolyte microcapsules are promising carriers of drugs and diagnostic agents for designing targeted and controlled delivery systems design. The use of quantum dots (QDs) as fluorescent labels in bioimaging is a promising approach to bioimaging tool development. The potential toxicity of QDs makes their applicability as fluorescent labels in vivo questionable. Therefore, the cytotoxicity of polyelectrolyte microcapsules encoded with semiconductor nanocrystals has been investigated. Keywords: Polyelectrolyte microcapsules, semiconductor nanocrystals, cytotoxicity, theranostic agents

Chronobiological approach to study microsymbiont catalase activity in female reproductive tract

Catalase is a heme-containing enzyme belonging to protection factors that destroys peroxide compounds. The presence of catalase activity is an important ability of microorganisms that allows them to be protected from unfavorable factors as well as adapt to macroorganism conditions. Catalase along with superoxide dismutase plays an important role in pathogen resistance to phagocyte oxygen-dependent bactericidal mechanisms. The aim of the study was to investigate microsymbiont catalase activity from female reproductive tract in normocenosis and candidiasis dysbiosis using the chronobiological approach. The study was conducted on clinical isolates, isolated from female reproductive tract microsymbiocenosis. The catalase activity was determined by spectrophotometry based on 24 hour-long hydrogen peroxide reduction with 3-hours interval in winter season. Dynamic hydrogen peroxide was assessed in 3–5 experiment replicates. In some Lactobacillus spp., catalase was found containing no heme group — pseudocatalase. Chronobiological approach allowed to reveal enzyme activity from all microsymbionts. The dominant and associative microbiota isolated from healthy females was characterized by circadian (24 hours) rhythms of catalase activity early in the morning — 5 a.m. (р 0.05). Hydrogen peroxide decomposes spontaneously or via non-enzymatic catalysts, and microorganisms cope with this situation under such conditions. In microsymbionts characteristic of female reproductive tract dysbiosis, and usually found in large numbers along with decreased Lactobacillus spp. ultradian rhythms with 12- and 8-hour harmonics of catalase activity with acrophase were recorded in the morning (8 a.m.) and evening hours (8 p.m.). The minimum values of enzyme production in all cultures were recorded at 12 p.m. and 5 p.m. Therefore, the contribution of the rhythm of the studied parameter at varying degree of vaginal sterility reflects the adaptive pathogen capabilities to the conditions of existence and can be the basis for studying related regulatory mechanisms. Mesor and amplitude phase stability are universal rhythmometric parameters used to evaluate patient’s condition independent of species assignment

Chronobiological approach to study the physiological activity of <i>Candida</i> species

Rythmometric markers can be identified within a day during the study of biological characteristics in order to be used for differential diagnostics of pathogens of different patients’ physical condition. These principles are based on analysis of clinical isolates С. albicans, С. tropicalis and C. krusei allocated from the vaginal microbiota at Candida dysbiosis condition. Control examples were the master samples from the American Type Culture Collection (ATCC). Detailed research was conducted on physiological characteristics through the formation of biofilms by yeast pathogens. Biological activity of Candida sp. biofilming was observed within 2 days with 4 hours interval in winter. Daily cultures were used for the experiment to correspond to their maximum adhesion to the glass surface. It was important to obtain 6 measurements per day with 3-5 times repetition of experiment conditions during the specified timeline. In order to determine the periodicity of the parameters studied, the data was statistically processed by Student’s t-test, using Mann–Whitney criteria and nonparametric method of least square method.It was found out that biofilming activity during 24 hours (р &lt; 0.05) of fungi exists and that all species have many principles in common. It was attested that the main rhythmometric parameters of diagnostic significance are the rhythm period and amplitude-phase stability. It was found that the daily dynamics of C. albicans 24433 biofilm formation from American Type Culture Collection was characterized by an ultradian (about 12-hours) contribution of the rhythm in the morning – 4 A.M and in the evening – 4 P.M. Significant circadian (approx. daily) rhythms of adhesion glass surface activity were revealed in C. non-albicans from American Type Culture Collection. The dynamic of biofilm formation isolates of yeast from female reproductive organs with Candida pathology was characterized by reliable ultradian (about 12-hour) harmonics which biological significance defines resistance to external impact and the ability to adaptively respond to periodic stimuli.To sum up, implementation of the chronobiological approach has opened up new prospects for studying the physiology of Сandida sp., as it enables us to predict the dynamics of microbial states and takes into account the specificity of emergency and long-term adaptation to different environmental factors. The detection of the circadian rhythm of biofilm formation activity of different Candida sp. strains provides the possibility to manage the vitality of the Society of Bacteria and Fungi and predicts its resistance to various antibiotics

Study of social network interference of memory processes in adolescence

Memory is the fundamental basis of human learning. Conceptual assessment and study of the memory mechanisms, its formation, consolidation and preservation at different levels of the structural and functional organization of the nervous system constitutes the necessary knowledge for solving many problems of practical and fundamental psychology. This article presents the study of memory, namely the process of its transition from a short-term to a more stable long-term form in a digital environment under the influence of the interference factor of social networks. The aim of the work is to study the influence of the social network interference factor on the processes of consolidation and reconsolidation of memory in adolescence. The total sample size was 68 adolescents aged 12–17 years. The authors conducted an experiment to achieve this goal. Its results showed that adolescents have difficulty remembering information in the form of short, successive videos in the digital space. It was found that videos that are characterized not only by visual accompaniment, but also by speech production are subject to better memorization. Under the influence of the interfering factor of social networks, adolescents faced difficulties in linking individual elements of stimuli with each other – they connected elements of one video with elements of another. According to one of the provisions of the theory of interference, information storage is characterized by the “unbinding” of representations of objects, followed by their reverse linking in an arbitrary combination during further reproduction

Скрининг детей и подростков на туберкулезную инфекцию в России – прошлое, настоящее, будущее

The article presents a brief overview of the establishment and development of screening system in the pediatric population for tuberculosis and latent tuberculosis infection - from Koch alt-tuberculin to modern recombinant tuberculosis allergens for intradermal administration and in vitro laboratory tests. It gives extensive data on clinical research and the introduction into practical public health of the Russian Federation of the test with recombinant tuberculosis allergen as a screening method for tuberculosis in children from 8 to 14 years old inclusively.Представлен краткий обзор становления и развития системы скрининга детского населения на туберкулез и на латентную туберкулезную инфекцию – от альт-туберкулина Коха до современных рекомбинантных аллергенов туберкулезных для внутрикожного введения и лабораторных тестов in vitro. Приведены обширные данные о клиническом исследовании и внедрении в практическое здравоохранение РФ пробы с аллергеном туберкулезным рекомбинантным в качестве скрининга на туберкулез у детей с 8 до 14 лет включительно

Лучевые методы в диагностике и стадировании рака желудка

Purpose. To assess the possibilities of methods of radiation diagnosis in the recognition and staging of gastric cancer.Material and methods. The results of inspection of 307 patients with cancer of a stomach at which endoscopic, radiological and computer tomography researches on purpose, both primary diagnosis of gastric cancer, and establishment of a staging of process have been executed have been analyzed from 2014 to 2017.Results. At a radiological research proximal cancer of a stomach is revealed at 63 (20,5%) patients, a body – at 202 (65.8%) and distally – at 42 (13.7%) patients. In all cases we managed to diagnose precisely stomach cancer, its localization and distribution on stomach walls. MSCT allowed to determine the spread of the tumor beyond the organ. Results of comprehensive examination of patients with cancer of a stomach have allowed to stage the process. The first stage has been established at 40 (13.0%) patients, second – at the 117 (38.2%), third – at the 102 (33.2%), fourth – at 48 (15.6%). Of the 307 patients with gastric cancer, various types of interventions were subsequently performed in 254 (83%), chemotherapy, as an independent type of treatment was performed in 49 (16%), refused any treatment of 4 (1%) patients.Conclusion. Complex radiation diagnosis is highly informative for the detection and staging of stomach cancer.Цель исследования: оценить возможности лучевой диагностики в распознавании и стадировании рака желудка.Материал и методы. Проанализированы результаты обследования 307 больных раком желудка, у которых были выполнены эндоскопические, рентгенологические и компьютерно-томографические исследования с целью как первичной диагностики рака желудка, так и установления стадии процесса, пролеченных за период с 2014 по 2017 г.Результаты. При рентгенологическом исследовании проксимальный рак желудка выявлен у 63 (20,5%) больных, тела – у 202 (65,8%) и дистальный – у 42 (13,7%) больных. Во всех случаях нам удалось точно диагностировать рак желудка, установить его локализацию и распространение по стенкам желудка. МСКТ позволила определить распространение опухоли за пределы органа. В результате комплексного лучевого обследования больных раком желудка удалось установить стадию процесса. I стадия была выявлена у 40 (13,0%) больных, II – у 117 (38,2%), III – у 102 (33,2%), IV – у 48 (15,6%). Из 307 больных раком желудка в последующем были выполнены различные виды хирургических вмешательств у 254 (83%), химиотерапия, как самостоятельный вид лечения выполнялась у 49 (16%), отказались от какого-либо лечения, 4 (1%) больных.Заключение. Комплексная лучевая диагностика высокоинформативна для выявления и стадирования рака желудка