Kravchik, Marina V

Motylkova E., Filatova S., Subbot A., Kravchik M., Kamynin V., Osipyan G., Novikov I., Kuznetsov S., Yusef Y.

This study examines the local transmission of normal and pathological corneal tissues when exposed to coherent collimated near-infrared (NIR) radiation with a wavelength of 1061 nm, highlighting its potential advantages over ultraviolet (UV) radiation for antimicrobial photodynamic therapy (PDT). The proposed measurement method, which employs an original experimental setup with a collimated NIR laser source and a probe fiber for direct layer-by-layer depth profiling, allows for determining the transmission values at specific depths within the cornea. Considering that the affected areas are localized within 1/3 to 1/2 of the corneal thickness, the residual power of the NIR radiation in the posterior part of the affected zone (at a depth of 250–400 µm) does not exceed 20%. However, the residual power of the NIR radiation at the posterior epithelium of the affected cornea, after passing through its entire thickness, does not exceed 10%. Current UV-based antimicrobial corneal PDT suffers from limited depth penetration and low specificity, hindering effective treatment and requiring photoprotectors to shield the non-regenerating posterior epithelium. NIR-based PDT, using selective photosensitizers, offers a promising alternative. The results of our NIR corneal transmittance measurements are crucial for the development of more targeted, effective, and safer therapies.

Kravchik M., Subbot A., Bilyalov A., Novikov I., Deviatiiarov R., Yusef Y., Gusev O.

A comprehensive understanding of intercellular and cell–matrix interactions is essential for advancing our knowledge of cell biology. Existing techniques, such as fluorescence microscopy and electron microscopy, face limitations in resolution and sample preparation. Supravital lanthanoid staining provides new opportunities for detailed visualization of cellular metabolism and intercellular interactions. This study aims to describe the structure, elemental chemical, and probable origin of zones of extreme lanthanoid (neodymium) accumulation that form during preparation for scanning electron microscopy (SEM) analysis in corneal fibroblasts filopodia. The results identified three morphological patterns of neodymium staining in fibroblast filopodia, each exhibiting asymmetric staining within a thin, sharp, and extremely bright barrier zone, located perpendicular to the filopodia axis. Semi-quantitative chemical analyses showed neodymium-labeled non-linear phosphorus distribution within filopodia, potentially indicating varying phosphate anion concentrations and extreme phosphate accumulation at a physical or physicochemical barrier. Phosphorus zones labeled with neodymium did not correspond to mitochondrial clusters. During apoptosis, the number of filopodia with extreme and asymmetric phosphorus accumulation increases. Supravital lanthanoid staining coupled with SEM allows detailed visualization of intercellular and cell–matrix interactions with high contrast and resolution. These results enhance our understanding of phosphate anion accumulation and transfer mechanisms in cells under normal conditions and during apoptosis.

Avetisov S.E., Rodina E.S., Kravchik M.V., Kosova J.V., Fettser E.I., Novikov I.A.

Standard bacteriological examinations, which involve culturing microorganisms at 37 °C, are commonly used in clinical practice for diagnosing infectious diseases. However, the growth temperature of microorganisms on the ocular surface (OS) during infectious keratitis (IK) may not coincide with the laboratory standard, which is due to the characteristic features of heat exchange in the eye.

Yusef Y.N., Petrachkov D.V., Korobov E.N., Novikov I.A., Kravchik M.V.

Purpose — to study the effect of a mid-infrared laser with a wavelength of 3.0 μm on the eye tissue. Materials and methods. An experimental laser device “Laser scalpel in the middle infrared range 2–8 μm for precision surgery” was used. The range of the radiation spectrum generated by this laser coincides with the spectral absorption peaks of such biological tissue chromophores as water, proteins and cholesterol esters, which makes it possible to use this laser in precision surgery (ophthalmology, neurosurgery, vascular surgery). In this study, we chose a wavelength of 3 µm, which coincides with the peak of the spectral absorption of water. The retina, choroid, sclera of porcine and cadaveric eyes was used as biological tissue. The effect of laser radiation on tissue was carried out in air. The application of coagulates was performed in different modes: 1) single pulses, 2) continuous mode. The impact of laser radiation on eye tissues was assessed using a scanning electron microscope. Results. When exposed to a single laser pulse with an energy of even 1 mJ, a through defect of the retina was observed. When exposed to a single laser pulse on the choroid with an energy of 1 to 3 mJ, the depth of the crater was 110–130 µm, the width of the crater was 97–122 µm, and the zone of collateral damage was 22–28 µm. When exposed to a single laser pulse on the sclera with an energy of 1 to 3 mJ, the depth of the crater was 170–201 µm, the width of the crater was 260–303 µm, and the zone of collateral damage was 57–72 µm. With continuous exposure to laser radiation on the choroid and sclera, the depth, width of the coagulate, the zone of collateral damage with similar laser parameters were greater than with a single pulse. Conclusion. Using this laser at a wavelength of 3 μm, it is possible to dissect eye tissues, which can be useful in vitreoretinal surgery for retinotomy, cutting out the choroid-pigment epithelium complex, and in antiglaucoma surgery for non-penetrating deep sclerectomy. However, further research is needed to optimize such laser parameters as the number of pulses in a packet, pulse duration, and pulse energy.

Nefedova S.M., Novikov I.A., Kravchik M.V., Zolotenkov D.D., Subbot A.M., Pigolkin Y.I.

Was to assess the possibility of using chemical analysis of bone mineral content by the means of an energy dispersive X-Ray spectroscopy to determine the age of unidentified corpses for forensic identification. A semi-quantative chemical microanalysis of bone fragments of 85 male and female corpses aged between 21 and 91 was done through the use of energy dispersive X-Ray spectrometer. The association of bone tissue apatite mineral composition with age is confirmed and a formula, connecting age and chemical composition change, is proposed. The possibility of using quantitive evaluation of chemical elements content in the normative mineral to determine the unidentified corpse's age in a standard laboratory, equipped with an energy dispersive X-Ray spectrometer, was proved.Оценить возможность использования химического анализа минерального вещества костной ткани с помощью энергодисперсионной рентгеновской спектроскопии для установления возраста при судебно-медицинской идентификации личности неопознанных трупов. С помощью энергодисперсионного рентгеновского спектрометра проведен полуколичественный химический микроанализ фрагментов костной ткани от 85 трупов лиц мужского и женского полов в возрасте от 21 до 91 года. Подтверждена связь минерального состава апатита костной ткани с возрастом и предложена формула, связывающая возраст и изменение химического состава. Доказана возможность применения количественной оценки содержания химических элементов в нормативном минерале для установления возраста неопознанного трупа в условиях стандартной лаборатории, оснащенной энергодисперсионным рентгеновским спектрометром.

Antoshin A., Dubinin O., Miao L., Istranova E., Bikmulina P., Fayzullin A., Magdanov A., Kravchik M., Kosheleva N., Solovieva A., Sadchikova E., Kotova S., Efremov Y., Qu X., Butnaru D., et. al.

Collagen membranes with high robustness and a defined stable biodegradation are of a great interest for dental surgery. Electrophoretic deposition (EPD) is a perspective candidate technology for their production, and in this article, the authors demonstrated the capabilities of its modification, a semipermeable barrier-assisted EPD (SBA-EPD). The SBA-EPD process was carried out at 60 V for 1,2, or 3 cycles 20 min each, after which the obtained membranes were crosslinked with 0.625% genipin. SBA-EPD allowed for the fabrication of membranes with high collagen packing density (0.0012 g/mm3) and high robustness, which depended on the number of SBA-EPD cycles. The highest Young’s modulus, tensile strength, and strain at failure values of non-crosslinked samples corresponded to 3-cycle deposition (15.11 ± 1.78 MPa, 4.2 ± 1.6 MPa, 60 ± 12%, respectively). However, crosslinking diminished the statistical difference of these parameters among membranes of different deposition cycles (reaching for 3-cycle deposition 64 ± 5 MPa, 9.5 ± 1.1 MPa, 23.7 ± 2.0%, respectively). On day 21 after subcutaneous implantation, the non-crosslinked membranes showed a significant degree of resorption higher than that of crosslinked ones by 3.5 times in absolute values. As well, crosslinked membranes elicited a greater peri-implant pro-fibrotic and giant cell response. Overall, the mechanical characteristics of SBA-EPD membranes were mostly superior to commercially available products used for dental applications, while their biodegradation timeframes fitted the optimal window. The authors hope that their research will attract the attention to SBA-EPD as an emerging and perspective technology for the production of robust and defect-free collagen membranes for dental surgery.

Novikov I.A., Kravchik M.V., Pak O.A., Kasparova E.A., Yartsev V.D., Rodina E.S., Solodovnikov V.I., Subbot A.M.

This review describes the history of development of a new line of chemical reagents that prompts to significantly reevaluate the application of scanning electron microscopy (SEM) in medical and biological studies, particularly in ophthalmology; considers the establishing of SEM as an analytical method; covers the problems in its application associated with the needs of clinical medicine and the complexities of biological sample preparation for electron microscopy. The article also presents in chronological order the technical solutions associated with creating a unique line of reagents for supravital staining. The multitude of technical solutions allows considering SEM as a method of express diagnostics. The review discusses examples of practical application of these methods for solving certain cases in clinical ophthalmology. The niche of SEM is considered among other methods of clinical diagnostics, as well as its future development involving the use of artificial intelligence.В обзоре раскрывается история создания новой линейки реактивов, позволяющей существенно пересмотреть методы применения сканирующей электронной микроскопии в медико-биологических исследованиях, в частности в офтальмологии. Рассматривается становление электронной микроскопии в качестве аналитического метода. Освещаются проблемы применения, связанные с конфликтом потребностей клинической медицины и сложностью подготовки биологического образца для электронной микроскопии. В хронологическом порядке в обзоре рассмотрены предлагаемые технические решения, связанные с созданием уникальной линейки реактивов для суправитального применения. Совокупность технических решений позволяет рассматривать сканирующую электронную микроскопию в качестве экспресс-метода диагностики. В обзоре приведены примеры практического использования предложенных методик для решения некоторых конкретных ситуаций клинической офтальмологии. Рассматривается ниша сканирующей электронной микроскопии среди прочих методов клинической диагностики и возможное развитие метода с привлечением искусственного интеллекта.

Pakhomova N.A., Borisenko T.E., Roshchin S.V., Bursov A.I., Kravchik M.V., Novikov I.A., Avetisov S.E.

This study provides a detailed analysis of the bioinorganic chemical composition of lens substance in patients with senile cataract using classical and spatial statistics methods.The study included 30 isolated human lenses. The light scattering ability (LSA) of the lens substance was evaluated using an original method. Additionally, distribution of chemical elements in the lens substance was analyzed using a scanning electron microscope with energy dispersive spectrometer (SEM/EDS). Measurements by all methods were carried out in a single coordinate space, which made it possible to compare the spatial correlation of different parameters.Small-angle light scattering of the lens substance has been quantitatively characterized for the first time. In contrast to the conventional norm, in senile cataract the accumulation fields of the majority of ion-forming elements (including Na, P, K, Cl) are distributed along the lines repeating the geometry of the lens capsule. At the same time, the light scattering ability of certain areas of the lens is significantly correlated with changes in the concentrations of Na, P, K, Ca in these areas. In particular, one ion-forming element can be distinguished - Na: spatial change of its concentration in senile cataract is strongly associated with a local change in LSA of the lens with opacities clustering of any degree. Thus, a change in the nature of the Na accumulation in the lens volume can be considered the main marker of senile cataract formation.The distribution pattern of ion-forming elements indicates that the loss of barrier properties in the capsule plays a significant role in the development of senile cataract.Детальный анализ бионеорганического химического состава вещества хрусталиков человека при сенильной катаракте с привлечением методов классической и пространственной статистики.Объектом исследования послужили 30 изолированных хрусталиков человека. Оценивали светорассеивающую способность (СРС) вещества хрусталика оригинальным методом, а также распределение химических элементов в объеме вещества хрусталика при помощи сканирующего электронного микроскопа с энергодисперсионным спектрометром. Измерения всеми методами проводились в едином координатном пространстве, что позволило сравнить пространственную корреляцию разных параметров.Впервые количественно охарактеризовано малоугловое оптическое рассеяние света веществом хрусталика. Было показано, что при катаракте, в отличие от условной нормы, поля накопления большинства ионообразующих элементов (среди которых Na, P, K, Cl) распределяются по линиям, повторяющим геометрию капсулы хрусталика. При этом СРС определенных областей вещества хрусталика статистически значимо коррелирует с изменением в этих областях концентраций Na, P, K, Ca. Следует особо выделить один ионообразующий элемент — Na, пространственное изменение концентрации которого при катаракте статистически связано с локальным изменением СРС хрусталиков при любой степени кластеризации помутнений, что позволяет говорить об изменении характера накопления Na в объеме вещества хрусталика как о главном маркере развития сенильной катаракты.Выявленный характер распределения ионообразующих элементов свидетельствует о значимой роли потери барьерных свойств капсулы в развитии сенильной катаракты.

Kravchik M.V., Rodina E.S., Subbot A.M., Pimonova O.I., Fettser E.I., Novikov I.A.

To determine the possibilities of impression cytology (IC) with subsequent visualization of the sample on a scanning electron microscope in assessment of normal microflora of the ocular surface.The article presents a visual characteristic of the microorganisms of the ocular surface (OS) captured during impression cytology (IC) in individuals without signs of inflammatory and degenerative eye diseases. The original method of staining the sample with heavy metal salts made it possible to identify the individual signs of the microorganisms in their subsequent visualization by scanning electron microscopy (SEM).The paper presents photomicrographs of the microorganisms most common for the OS obtained with the help of SEM, confirming and supplementing the data of non-visual methods of studying the ocular microflora. It was shown that the detection frequency of the microbial component of the OS by the visual method presented in this study is comparable with the detection frequency when using the microbial cultivation method (

Sevastianov V.I., Basok Y.B., Grigoriev A.M., Nemets E.A., Kirillova A.D., Kirsanova L.A., Lazhko A.E., Subbot A., Kravchik M.V., Khesuani Y.D., Koudan E.V., Gautier S.V.

AbstractOne of the approaches to restoring the structure of damaged cartilage tissue is an intra‐articular injection of tissue‐engineered medical products (TEMPs) consisting of biocompatible matrices loaded with cells. The most interesting are the absorbable matrices from decellularized tissues, provided that the cellular material is completely removed from them with the maximum possible preservation of the structure and composition of the natural extracellular matrix. The present study investigated the mechanical, biochemical, and biological properties of decellularized porcine cartilage microparticles (DCMps) obtained by techniques, differing only in physical treatments, such as freeze–thaw cycling (Protocol 1), supercritical carbon dioxide fluid (Protocol 2) and ultrasound (Protocol 3). Full tissue decellularization was achieved, as confirmed by the histological analysis and DNA quantification, though all the resultant DCMps had reduced glycosaminoglycans (GAGs) and collagen. The elastic modulus of all DCMp samples was also significantly reduced. Most notably, DCMps prepared with Protocol 3 significantly outperformed other samples in viability and the chondroinduction of the human adipose‐derived stem cells (hADSCs), with a higher GAG production per DNA content. A positive ECM staining for type II collagen was also detected only in cartilage‐like structures based on ultrasound‐treated DCMps. The biocompatibility of a xenogenic DCMps obtained with Protocol 3 has been confirmed for a 6‐month implantation in the thigh muscle tissue of mature rats (n = 18). Overall, the results showed that the porcine cartilage microparticles decellularized by a combination of detergents, ultrasound and DNase could be a promising source of scaffolds for TEMPs for cartilage reconstruction.

Kravchik M.V., Zolotenkova G.V., Grusha Y.O., Pigolkin Y.I., Fettser E.I., Zolotenkov D.D., Gridina N.V., Badyanova L.V., Alexandrov A.A., Novikov I.A.

One of the most common scientific methods to study the chemical composition of bone matter is energy-dispersive X-ray spectroscopy (EDS). However, interpretation of the data obtained can be quite complicated and require a thorough understanding of bone structure. This is especially important when evaluating subtle changes of chemical composition, including the age-related ones. The aim of current study is to create a method of processing the obtained data that can be utilized in clinical medicine and use it to evaluate the age evolution of bone chemical composition. To achieve this goal, an elemental composition of 62 samples of cadaver compact bone, taken from the skull base (age: Me = 57.5; 21/91(min/max); Q1 = 39.5, Q3 = 73.75), was studied with EDS. We used the original method to estimate the amount of Mg2+ cations. We detected and confirmed an increase of Mg2+ cation formula amount in the bone apatite, which characterizes age-related resorption rate. Analysis of cation estimated ratio in a normative bone hydroxylapatite showed an increase of Mg2+ amount (R = 0.43, p = 0.0005). Also, Ca weight fraction was shown to decrease with age (R = − 0.43, p = 0.0005), which in turn confirmed the age-dependent bone decalcification. In addition, electron probe microanalysis (EPMA) and X-ray diffraction analysis (XRD) were performed. EDS data confirmed the EPMA results (R = 0.76, p = 0.001). In conclusion, the proposed method can be used in forensic medicine and provide additional data to the known trends of decalcification and change of density and crystallinity of mineral bone matter.

Петров С.Ю., Антонов А.А., Суббот А.М., Новиков И.А., Кравчик М.В.

Цель. Оценка процессов минерализации, происходящих в передней камере глаза при открытоугольной глаукоме.Материалы и методы. На сканирующем электронном микроскопе EVO LS 10 (Zeiss, Германия) с энергодисперсионным рентгеновским спектрометром Oxford X-Max-50 (Oxford, Великобритания) проводился химический анализ полученной интраоперационно трабекулярной ткани 29 пациентов (30 глаз) в возрасте 73 (58; 78) лет с открытоугольной глаукомой II–III стадий, а также пигментного материала, полученного из радужки 5 кадаверных глаз. Поверхность всех образцов визуализировали в СЭМ с помощью детектора обратно-рассеянных электронов (BSE) в режиме низкого вакуума (EP, 70 Па) при ускоряющем напряжении 21,5 кВ и токе на образце 20–60 пА. Валовый химический микроанализ и микрокартирование проводили для выборочных химических элементов: C, N, O, Ca, Cl P, Si, S.Результаты. В 7 из 30 образцов была выявлена значимая по площади минеральная облитерация ткани дренажной зоны: силитизация – в 3 образцах, кальцификация – в 4 образцах. Также in vitro был получен эффект автономной кальцификации гранул пигмента: на их поверхности при моделировании витальных условий выявлялась минеральная фаза, стехиометрически соответствующая дикальциевому фосфат дигидрату (ДКФД) и аморфному фосфату кальция (АФК).Заключение. Был выделен тип открытоугольной глаукомы, при которой кальциевая и кремниевая облитерация является потенциально значимым компонентом ретенции на уровне трабекулярной ткани. В эксперименте с пигментом был смоделирован механизм, способствующий кальцификации дренажный зоны. Был сделан вывод о нарушениях кислотно-основного баланса в области трабекулы, способствующих созданию минеральной облитерации. Purpose. To define mineralization processes that occur in the anterior chamber of the eye in case of open-angle glaucoma.Materials and methods. The chemical composition assessment of trabecular tissue samples from 29 patients (30 eyes) aged 73 (58;78) with open-angle glaucoma (stages II–III) as well as elemental analyses of iris pigment material obtained from 5 cadaver eyes was performed using a scanning electron microscope (SEM) "EVO LS 10" (Zeiss, Germany) with an energy-dispersive spectrometer (EDS) "Oxford-X-MAX-50" (Oxford, UK). Images were acquired using a backscattered electron detector (BSE) in the SEM in a low vacuum mode (EP, 70 Pa) at an accelerating voltage of 21.5 kV and a probe current of 20–60 pA. Bulk microanalysis and micro-mapping were performed for certain chemical elements: C, N, O, Ca, Cl, P, Si, S.Results. 7 out of 30 tissue samples obtained from the drainage area demonstrated significant mineralization: silicification in 3 samples and calcification in 4 samples. Also, the autonomous calcification effect was discovered in simulated experimental conditions (in vitro): a mineral phase was identified on pigment granules’surface with a stoichiometric correspondence to dicalcium phosphate dihydrate (DCPD) and amorphous calcium phosphate (ACP).Conclusion. A type of open-angle glaucoma associated with calcium and silicon obliteration as a potential factor for retention in trabecular meshwork tissue was determined. In a pigment experiment, a process was simulated that causes the calcification of the drainage zone. It was noted that acid-base imbalance in tissue contributes to mineral obliteration.

Musina G.R., Chernomyrdin N.V., Gafarova E.R., Gavdush A.A., Shpichka A.J., Komandin G.A., Anzin V.B., Grebenik E.A., Kravchik M.V., Istranova E.V., Dolganova I.N., Zaytsev K.I., Timashev P.S.

In this paper, terahertz (THz) pulsed spectroscopy and solid immersion microscopy were applied to study interactions between water vapor and tissue scaffolds-the decellularized bovine pericardium (DBP) collagen matrices, in intact form, cross-linked with the glutaraldehyde or treated by plasma. The water-absorbing properties of biomaterials are prognostic for future cell-mediated reactions of the recipient tissue with the scaffold. Complex dielectric permittivity of DBPs was measured in the 0.4-2.0 THz frequency range, while the samples were first dehydrated and then exposed to water vapor atmosphere with 80.0 ± 5.0% relative humidity. These THz dielectric measurements of DBPs and the results of their weighting allowed to estimate the adsorption time constants, an increase of tissue mass, as well as dispersion of these parameters. During the adsorption process, changes in the DBPs' dielectric permittivity feature an exponential character, with the typical time constant of =8-10 min, the transient process saturation at =30 min, and the tissue mass improvement by =1-3%. No statistically-relevant differences between the measured properties of the intact and treated DBPs were observed. Then, contact angles of wettability were measured for the considered DBPs using a recumbent drop method, while the observed results showed that treatments of DBP somewhat affects their surface energies, polarity, and hydrophilicity. Thus, our studies revealed that glutaraldehyde and plasma treatment overall impact the DBP-water interactions, but the resultant effects appear to be quite complex and comparable to the natural variability of the tissue properties. Such a variability was attributed to the natural heterogeneity of tissues, which was confirmed by the THz microscopy data. Our findings are important for further optimization of the scaffolds' preparation and treatment technologies. They pave the way for THz technology use as a non-invasive diagnosis tool in tissue engineering and regenerative medicine.

Kravchik M.V., Novikov I.A., Petrov S.Y., Avetisov S.E.

At present, physical methods of chemical analysis are constantly improving providing large amount of data on elemental composition of organs and tissues. However, only few works describe the correlation (or the potential connection) between the general or local bioelemental imbalances and specific biochemical reactions that are involved in pathogenesis of certain diseases. This review describes primary open-angle glaucoma (POAG) – one of the most common ophthalmic diseases – in terms of elemental chemistry. The authors look into the impact that various subgroups of elements have on passive and active processes of homeostasis regulation and hydrodynamic balance in the eye. Alkaline metals and their analogues (K, Na, Li, Rb, Cs) influence hydrostatics and hydrodynamics by means of both K-Na pumps and osmosis. Alkaline-earth elements and their analogues (Ca, Mg, Sr, Ba, Be) are involved in biomineralization and intercellular interaction in the drainage areas. Chalcophile metals and their analogues (Zn, Cu, Hg, Co, Ni, Cd, Pb, Mo, Sb) regulate redox reactions. They are the cofactors of enzymes that support structural homeostasis of the drainage area. Siderophile metals (Fe, Mn, Cr, Rh) regulate oxidation-reduction reactions, including those associated with limited nutrition of tissues in glaucoma. The role of amphoteric metals and nonmetals (Al, Si, Ga, V, TI, Sn, Ge, Zr, W) in POAG has not been described properly, but they were noted to participate in mineralization. Structure-forming non-metals and their analogues (N, S, Se, As) are directly involved in the formation of protein and non-protein aggregates that prevent aqueous humor outflow. The specific role of phosphorus in the pathogenesis of glaucoma has not been described previously. The authors analyze the involvement of phosphorus in energy-dependent processes of cellular activity, which are aimed at the reprocessing of aggregates that cause aqueous humor retention.

Kravchik M.V., Subbot A.M., Novikov I.A., Antonov A.A., Petrov S.Y., Avetisov S.E.

A new form of open-angle glaucoma has been identified, in which calcification and silicification of the trabecular meshwork is a potentially significant component of outflow obstruction. It is noted that the mineralization of this area is promoted by various disturbances in the acid–base balance in the tissue. The role of melanosomal enzymes in the initiation of the formation of mineral calcium phosphate in trabecular tissue in open-angle glaucoma is considered.

Liang B., Bai R., Wang J., Shi S., Guo Y., Wang Q., Peng H., Tang J., Liu S., Zhu J., Yi C., Hou M., Li H.

Zihna G., Kilic B., Topuz B., Gunal G., Aydin H.M.

Gavdush A.A., Zhelnov V.A., Dolganov K.B., Bogutskii A.A., Garnov S.V., Burdanova M.G., Ponomarev D.S., Shi Q., Zaytsev K.I., Komandin G.A.

Vanadium dioxide ( $$\hbox {VO}_2$$ ) is a favorable material platform of modern optoelectronics, since it manifests the reversible temperature-induced insulator-metal transition (IMT) with an abrupt and rapid changes in the conductivity and optical properties. It makes possible applications of such a phase-change material in the ultra-fast optoelectronics and terahertz (THz) technology. Despite the considerable interest to this material, data on its broadband electrodynamic response in different states are still missing in the literature. This hampers the design and implementation of the $$\hbox {VO}_2$$ -based devices. In this paper, we combine the Fourier-transform infrared (FTIR) spectroscopy, THz pulsed spectroscopy (TPS), and four-contact probe method to study the $$\hbox {VO}_2$$ films prepared by magnetron sputtering on a c-cut sapphire substrate. Considering different temperatures of a substrate and pressures of atmosphere, we reconstruct complex dielectric permittivity of $$\hbox {VO}_2$$ film in the frequency range of 0.2–150 THz, along with its static conductivity. The dielectric response is modeled using Lorentz and Drude kernels, which make possible splitting contributions from vibrational modes and free charge carriers to the total dynamic conductivity. By studying $$\hbox {VO}_2$$ at different substrate temperatures and atmosphere pressures, we show that IMT appears to be pressure-dependent, which we attribute to the different thermostatic conditions of a sample. Finally, we estimate somewhat optimal thickness and temperature of the $$\hbox {VO}_2$$ film in metallic phase for the THz optoelectronic applications. Our finding should be useful for further developments of the $$\hbox {VO}_2$$ -based devices and technologies.

Yanoff M., Sassani J.W.

This chapter contains a comprehensively revised discussion of the anatomic basis for aqueous outflow and the histopathologic correlates in glaucoma. The information on the genetics of glaucoma is revised extensively as is the discussion of pathobiology for each of the pseudoexfoliation. Much information has been added regarding the pathobiology of optic nerve damage in glaucoma.

Xu J., Jiang N., Zhu S., Alini M., Grad S., Geurts J., Li Z.

Illesinghe S.D., Sundaresan V.

Microplastics (MPs) are global pollutants found in various environmental compartments, including oceans, freshwater bodies, soils, and air. Their persistence and potential to adsorb heavy metals raise significant concerns regarding water quality and ecosystem health. Understanding the interaction between MPs and heavy metals is crucial for assessing environmental risks and developing remediation strategies. In this study, we use electroanalytical techniques to investigate the adsorption of heavy metal ions— Cr³⁺, Zn²⁺, and Ni²⁺—by polystyrene MPs with different surface functionalizations: carboxyl, amino, and unfunctionalized. We conducted electrodeposition of metal ions on a gold ultramicroelectrode both before and after mixing with MPs. Following this, we used anodic stripping voltammetry to measure the change in the electrodeposited charge (ΔQ). This charge difference, observed before and after the interaction of ions with MPs, was analyzed to understand the adsorption kinetics and dynamics. Our experiments revealed that carboxyl-functionalized MPs exhibited the highest ΔQ due to strong electrostatic attraction with the metal ions, with values 1.67 ×, 1.50 ×, and 1.22 × greater than those for amino-MPs for Cr³⁺, Zn²⁺, and Ni²⁺, respectively. Amino-MPs displayed considerable ion adsorption, suggesting poor electrostatic repulsion between two positively charged entities. Interestingly, unfunctionalized MPs, which had a negative surface charge similar to carboxyl-MPs, showed different adsorption characteristics, with lower ΔQ values for all metal ions. This study underscores the significant role of surface functionalization on the adsorption efficiency and kinetics of heavy metal ions by MPs. It also demonstrates the utility of electroanalytical techniques in understanding metal ion-MP interactions, offering insights into potential environmental impacts and remediation strategies, as well as in developing electrochemical sensors for detecting heavy metal ions adsorbed on MPs.

Sevastianov V.I., Ponomareva A.S., Baranova N.V., Belova A.D., Kirsanova L.A., Nikolskaya A.O., Kuznetsova E.G., Chuykova E.O., Skaletskiy N.N., Skaletskaya G.N., Nemets E.A., Basok Y.B., Gautier S.V.

Producing a tissue-engineered pancreas based on a tissue-specific scaffold from a decellularized pancreas, imitating the natural pancreatic tissue microenvironment and the islets of Langerhans, is one of the approaches to treating patients with type 1 diabetes mellitus (T1DM). The aim of this work was to investigate the ability of a fine-dispersed tissue-specific scaffold (DP scaffold) from decellularized human pancreas fragments to support the islets’ survival and insulin-producing function when injected in a streptozotocin-induced diabetic rat model. The developed decellularization protocol allows us to obtain a scaffold with a low DNA content (33 [26; 38] ng/mg of tissue, p < 0.05) and with the preservation of GAGs (0.92 [0.84; 1.16] µg/mg, p < 0.05) and fibrillar collagen (273.7 [241.2; 303.0] µg/mg, p < 0.05). Rat islets of Langerhans were seeded in the obtained scaffolds. The rats with stable T1DM were treated by intraperitoneal injections of rat islets alone and islets seeded on the DP scaffold. The blood glucose level was determined for 10 weeks with a histological examination of experimental animals’ pancreas. A more pronounced decrease in the recipient rats’ glycemia was detected after comparing the islets seeded on the DP scaffold with the control injection (by 71.4% and 51.2%, respectively). It has been shown that the DP scaffold facilitates a longer survival and the efficient function of pancreatic islets in vivo and can be used to engineer a pancreas.

Telyatov B.A., Barishev K.V.

Relevance. The optic nerve pit is a congenital disease manifested by a depression in the disc of the optic nerve, which affects about 0.9% of the population. Complications occur in 25–75% of patients and may include retinal detachment. The causes of detachment remain unclear, but two theories of the occurrence of this complication have been put forward. Fluorescence angiography and optical coherence tomography are used for diagnosis. The treatment of retinal detachment in ONDP is not standardized and includes laser treatment, vitrectomy and other methods for fluid drainage. It is important to differentiate ONDP from other causes of central retinal detachment.Objective. Based on a clinical case, to demonstrate an approach to the diagnosis and treatment of local retinal detachment in the macular area associated with the fossa of the optic disc.Materials and methods. This article presents a clinical case of retinal detachment in the macular area associated with the fossa of the optic disc. Results and discussions. When comparing two clinical cases, the similarity of the ophthalmoscopic picture and the differences in the OCT and FAG images were revealed.Conclusions. The accumulation of fluid under the neuroepithelium is not a pathognomic sign, therefore it is important to carry out differential diagnosis in central serous retinal detachment associated with the fossa of the optic disc.

Baranykova S., Gupta R.K., Kajdasz A., Wasilewska I., Macias M., Szybinska A., Węgierski T., Nahia K.A., Mondal S.S., Winata C.L., Kuźnicki J., Majewski L.

AbstractCalcium is involved in vision processes in the retina and implicated in various pathologies, including glaucoma. Rod cells rely on store-operated calcium entry (SOCE) to safeguard against the prolonged lowering of intracellular calcium ion concentrations. Zebrafish that lacked the endoplasmic reticulum Ca2+ sensor Stim2 (stim2 knockout [KO]) exhibited impaired vision and lower light perception-related gene expression. We sought to understand mechanisms that are responsible for vision impairment in stim2 KO zebrafish. The single-cell RNA (scRNA) sequencing of neuronal cells from brains of 5 days postfertilization larvae distinguished 27 cell clusters, 10 of which exhibited distinct gene expression patterns, including amacrine and γ-aminobutyric acid (GABA)ergic retinal interneurons and GABAergic optic tectum cells. Five clusters exhibited significant changes in cell proportions between stim2 KO and controls, including GABAergic diencephalon and optic tectum cells. Transmission electron microscopy of stim2 KO zebrafish revealed decreases in width of the inner plexiform layer, ganglion cells, and their dendrites numbers (a hallmark of glaucoma). GABAergic neuron densities in the inner nuclear layer, including amacrine cells, as well as photoreceptors significantly decreased in stim2 KO zebrafish. Our study suggests a novel role for Stim2 in the regulation of neuronal insulin expression and GABAergic-dependent vision causing glaucoma-like retinal pathology.

Yu J., Liu Z., Hu J., Wang X., Zhang X., Shen J., Zhang Y.

In this paper, the dynamic characteristics of the cylindrical bubbles under triple-frequency acoustic excitation are investigated theoretically. The analytical solution of the primary-superharmonic-subharmonic (PRI-SUPER-SUB) simultaneous resonance is obtained through the multi-scale method. Based on the analysis of the frequency response, the influencing mechanisms of the primary parameters (e.g., the total amplitude, amplitude ratio, liquid viscosity, polytropic exponent, and bubble equilibrium radius) on the resonance are investigated quantitatively. The main conclusions include: (1) The solution for the simultaneous resonance of the cylindrical bubble exhibits jumping and hysteresis phenomena in the vicinity of the resonance frequency. (2) As the total amplitude, amplitude ratio, and equilibrium radius increase, the response amplitude of the PRI-SUPER-SUB simultaneous resonance increases, while the influence of the viscosity is the opposite. (3) The regions dominated by the instability of the simultaneous resonance is significantly affected by the system parameters.

Koteneva P., Kosheleva N., Fayzullin A., Khristidis Y., Rasulov T., Kulova A., Rozhkov S., Vedyaeva A., Brailovskaya T., Timashev P.

Currently, an increasing number of patients are undergoing extensive surgeries to restore the mucosa of the gums in the area of recessions. The use of a connective tissue graft from the palate is the gold standard of such surgical treatment, but complications, especially in cases of extensive defects, have led to the development of approaches using xenogeneic collagen matrices and methods to stimulate their regenerative and vasculogenic potential. This study investigated the potential of a xenogeneic scaffold derived from porcine skin Mucoderm and injections of the pCMV-VEGF165 plasmid (‘Neovasculgen’) to enhance soft gingival tissue volume and vascularization in an experimental model in rabbits. In vitro studies demonstrated the biocompatibility of the matrix and plasmid with gingival mesenchymal stem cells, showing no toxic effects and supporting cell viability and metabolic activity. In the in vivo experiment, the combination of Mucoderm and the pCMV-VEGF165 plasmid (0.12 mg) synergistically promoted tissue proliferation and vascularization. The thickness of soft tissues at the implantation site significantly increased with the combined application (3257.8 ± 1093.5 µm). Meanwhile, in the control group, the thickness of the submucosa was 341.8 ± 65.6 µm, and after the implantation of only Mucoderm, the thickness of the submucosa was 2041.6 ± 496.8 µm. Furthermore, when using a combination of Mucoderm and the pCMV-VEGF165 plasmid, the density and diameter of blood vessels were notably augmented, with a mean value of 226.7 ± 45.9 per 1 mm2 of tissue, while in the control group, it was only 68.3 ± 17.2 per 1 mm2 of tissue. With the application of only Mucoderm, it was 131.7 ± 37.1 per 1 mm2 of tissue, and with only the pCMV-VEGF165 plasmid, it was 145 ± 37.82 per 1 mm2 of the sample. Thus, the use of the pCMV-VEGF165 plasmid (‘Neovasculgen’) in combination with the xenogeneic collagen matrix Mucoderm potentiated the pro-proliferative effect of the membrane and the pro-vascularization effect of the plasmid. These results indicate the promising potential of this innovative approach for clinical applications in regenerative medicine and dentistry.

Zheng K., Li X., Qin X., Long H., Wu A.

Abstract Background This case mainly describes a relatively rare case of an old mineral-like corneal foreign body that existed for up to 20 years, and did not significantly affect the visual quality of the patient. Case presentation A 56-year-old male miner complained of right eye vision loss for 3 years, swollen and painful for 4 months. Admission examination: Best corrected visual acuity was no light perception in the right eye and 20/20 in the left eye. Anterior segment examination: A large number of spot-like grayish-brown mineral foreign bodies in the conjunctiva of the nasal conjunctiva, emulsified silicone oil floating in the anterior chamber, Corneal foreign bodies in the right eye were widely distributed in the upper cortex and the proelastic layer. There were fewer foreign bodies in the left cornea. Previous medical history, 20 years ago due to forging and burning sulphur mine explosion, resulting in a large number of ore foreign bodies in the conjunctiva of both eyes. As these corneal foreign bodies did not affect the visual quality of the patient, we adopted a conservative treatment plan, did not remove these foreign bodies, and only carried out symptomatic treatment for the patient’s secondary ocular hypertension. The patient was followed up normally in the outpatient department, and no cornea-related complications occurred up to now. Conclusions First of all, it is necessary to understand the source and nature of the foreign body in patients with corneal and conjunctival foreign body injuries. In the second, for the old corneal metal foreign body, when the patient’s visual acuity is stable and there are no symptoms of corneal irritation and inflammatory reaction, it can be Conservative treatment or outpatient follow-up observation. In the end, corneal Optical coherence tomography imaging should not be ignored, which is very important for determining the depth of embedding and the location of the corneal foreign body.

Barrino F., Vassallo V., Cammarota M., Lepore M., Portaccio M., Schiraldi C., La Gatta A.

Collagen-based membranes are class III-medical devices widely used in dental surgical procedures to favour bone regeneration. Here, we aimed to provide biophysical and biochemical data on this type of devices to support their optimal use and design/manufacturing. To the purpose, four commercial, non-crosslinked collagen-based-membranes, obtained from various sources (equine tendon, pericardium or cortical bone tissues, and porcine skin), were characterized in vitro. The main chemical, biophysical and biochemical properties, that have significant clinical implications, were evaluated. Membranes showed similar chemical features. They greatly differed in morphology as well as in porosity and density and showed a diverse ranking in relation to these latter two parameters. Samples highly hydrated in physiological medium (swelling-ratio values in the 2.5–6.0 range) and, for some membranes, an anisotropic expansion during hydration was, for the first time, highlighted. Rheological analyses revealed great differences in deformability (150-1500kPa G’) also alerting about the marked variation in membrane mechanical behaviour upon hydration. Samples proved diverse sensitivity to collagenase, with the cortical-derived membrane showing the highest stability. Biological studies, using human-bone-derived cells, supported sample ability to allow cell proliferation and to prompt bone regeneration, while no relevant differences among membranes were recorded. Prediction of relative performance based on the findings was discussed. Overall, results represent a first wide panel of chemical/biophysical/biochemical data on collagen-based-membranes that 1) enhances our knowledge of these products, 2) aids their optimal use by providing clinicians with scientific basis for selecting products based on the specific clinical situation and 3) represents a valuable reference for optimizing their manufacturing.

Rodina E.S., Fettser E.I., Novikov I.A.

This review compares data from scientific studies on the microbial community of the ocular surface (OS) in conditionally healthy individuals using cultural methods (including culture-dependent diagnostic tests), microscopic and molecular genetic methods, and assesses the influence of research methods and sample preparation on the results. Concordance and discordance of the sets of identified microorganisms were analyzed using overlapping and non-overlapping methods of studying the microbial community of a healthy OS. The article presents tables showing the names of microorganisms that were identified in different sources. Cross-verification in taxa of different ranks helped confirm the following most frequently found microorganisms on healthy OS: coccomorphic microorganisms of the genera

Kondratenko A.A., Tovpeko D.V., Volov D.A., Kalyuzhnaya L.I., Chernov V.E., Glushakov R.I., Sirotkina M.Y., Zemlyanoy D.A., Bildyug N.B., Chebotarev S.V., Alexander-Sinclair E.I., Nashchekin A.V., Belova A.D., Grigoriev A.M., Kirsanova L.A., et. al.

The umbilical cord is a material that enhances regeneration and is devoid of age-related changes in the extracellular matrix (ECM). The aim of this work was to develop a biodegradable scaffold from a decellularized human umbilical cord (UC-scaffold) to heal full-thickness wounds. Decellularization was performed with 0.05% sodium dodecyl sulfate solution. The UC-scaffold was studied using morphological analysis methods. The composition of the UC-scaffold was studied using immunoblotting and Fourier transform infrared spectroscopy. The adhesion and proliferation of mesenchymal stromal cells were investigated using the LIVE/DEAD assay. The local reaction was determined by subcutaneous implantation in mice (n = 60). A model of a full-thickness skin wound in mice (n = 64) was used to assess the biological activity of the UC-scaffold. The proposed decellularization method showed its effectiveness in the umbilical cord, as it removed cells and retained a porous structure, type I and type IV collagen, TGF-β3, VEGF, and fibronectin in the ECM. The biodegradation of the UC-scaffold in the presence of collagenase, its stability during incubation in hyaluronidase solution, and its ability to swell by 1617 ± 120% were demonstrated. Subcutaneous scaffold implantation in mice showed gradual resorption of the product in vivo without the formation of a dense connective tissue capsule. Epithelialization of the wound occurred completely in contrast to the controls. All of these data suggest a potential for the use of the UC-scaffold.

Guan F., Wu X., Zhou J., Lin Y., He Y., Fan C., Zeng Z., Xiong W.

AbstractA century ago, the Warburg effect was first proposed, revealing that cancer cells predominantly rely on glycolysis during the process of tumorigenesis, even in the presence of abundant oxygen, shifting the main pathway of energy metabolism from the tricarboxylic acid cycle to aerobic glycolysis. Recent studies have unveiled the dynamic transfer of mitochondria within the tumor microenvironment, not only between tumor cells but also between tumor cells and stromal cells, immune cells, and others. In this review, we explore the pathways and mechanisms of mitochondrial transfer within the tumor microenvironment, as well as how these transfer activities promote tumor aggressiveness, chemotherapy resistance, and immune evasion. Further, we discuss the research progress and potential clinical significance targeting these phenomena. We also highlight the therapeutic potential of targeting intercellular mitochondrial transfer as a future anti-cancer strategy and enhancing cell-mediated immunotherapy. Graphical Abstract

Matsubayashi H.T., Mountain J., Takahashi N., Deb Roy A., Yao T., Peterson A.F., Saez Gonzalez C., Kawamata I., Inoue T.

AbstractClass IA phosphoinositide 3-kinase (PI3K) galvanizes fundamental cellular processes such as migration, proliferation, and differentiation. To enable these multifaceted roles, the catalytic subunit p110 utilizes the multi-domain, regulatory subunit p85 through its inter SH2 domain (iSH2). In cell migration, its product PI(3,4,5)P3 generates locomotive activity. While non-catalytic roles are also implicated, underlying mechanisms and their relationship to PI(3,4,5)P3 signaling remain elusive. Here, we report that a disordered region of iSH2 contains AP2 binding motifs which can trigger clathrin and dynamin-mediated endocytosis independent of PI3K catalytic activity. The AP2 binding motif mutants of p85 aberrantly accumulate at focal adhesions and increase both velocity and persistency in fibroblast migration. We thus propose the dual functionality of PI3K in the control of cell motility, catalytic and non-catalytic, arising distinctly from juxtaposed regions within iSH2.

Komiyama M.

Nikolova V., Kircheva N., Dobrev S., Angelova S., Dudev T.

Lanthanides, the 14 4f-block elements plus Lanthanum, have been extensively used to study the structure and biochemical properties of metalloproteins. The characteristics of lanthanides within the lanthanide series are similar, but not identical. The present research offers a systematic investigation of the ability of the entire Ln3+ series to substitute for Ca2+ in biological systems. A well-calibrated DFT/PCM protocol is employed in studying the factors that control the metal selectivity in biological systems by modeling typical calcium signaling/buffering binding sites and elucidating the thermodynamic outcome of the competition between the “alien” La3+/Ln3+ and “native” Ca2+, and La3+ − Ln3+ within the lanthanide series. The calculations performed reveal that the major determinant of the Ca2+/Ln3+ selectivity in calcium proteins is the net charge of the calcium binding pocket; the more negative the charge, the higher the competitiveness of the trivalent Ln3+ with respect to its Ca2+ contender. Solvent exposure of the binding site also influences the process; buried active centers with net charge of −4 or −3 are characterized by higher Ln3+ over Ca2+ selectivity, whereas it is the opposite for sites with overall charge of −1. Within the series, the competition between La3+ and its fellow lanthanides is determined by the balance between two competing effects: electronic (favoring heavier lanthanides) and solvation (generally favoring the lighter lanthanides).

Wang Y., Wang Z., Dong Y.

Safonova E., Kolomeychuk F., Gvozdev D., Tsivadze A., Gorbunova Y.

The ability of P(V) phthalocyanines (Pcs) for efficient singlet oxygen (SO) generation was demonstrated for the first time by the example of unsubstituted and α- and β-octabutoxy-substituted P(V)Pcs with hydroxy, methoxy and phenoxy ligands in the apical positions of the octahedral P centre. Variation of substituents in Pc ring and P(V) axial ligands allows careful tuning of photophysical and photochemical properties. Indeed, a combination of BuO groups in the β-positions of the Pc ring and PhO groups as axial ligands provides significant SO generation quantum yields up to 90%; meanwhile, the values of SO generation quantum yields for others investigated compounds vary from 27 to 55%. All the complexes, except α-substituted P(V)Pc, demonstrate fluorescence with moderate quantum yields (10–16%). The introduction of electron-donating butoxy groups, especially in the α-position, increases the photostability of P(V)Pcs. Moreover, it has been shown in the example of β-BuO-substituted P(V) that the photostability depends on the nature of axial ligands and increases in the next row: OPh < OMe < OH. The presence of oxy/hydroxy axial ligands on the P(V) atom makes it possible to switch the photochemical and photophysical properties of P(V)Pcs by changing the acidity of the media.

Kravchik M.V., Rodina E.S., Subbot A.M., Pimonova O.I., Fettser E.I., Novikov I.A.

To determine the possibilities of impression cytology (IC) with subsequent visualization of the sample on a scanning electron microscope in assessment of normal microflora of the ocular surface.The article presents a visual characteristic of the microorganisms of the ocular surface (OS) captured during impression cytology (IC) in individuals without signs of inflammatory and degenerative eye diseases. The original method of staining the sample with heavy metal salts made it possible to identify the individual signs of the microorganisms in their subsequent visualization by scanning electron microscopy (SEM).The paper presents photomicrographs of the microorganisms most common for the OS obtained with the help of SEM, confirming and supplementing the data of non-visual methods of studying the ocular microflora. It was shown that the detection frequency of the microbial component of the OS by the visual method presented in this study is comparable with the detection frequency when using the microbial cultivation method (

Schofield E.R.

The palladium price has been rising because emissions legislation necessitates using more palladium in catalytic converters. However, this trend will not continue as the energy transition progresses, and in the future there will be considerably more palladium available to use in other applications, including chemicals, pharmaceuticals and agrochemicals catalysts. This is both opportunity and justification for the organic chemistry research community to develop new and significant uses for palladium that can be of global benefit. Any catalyst research needs to include optimisation of circular economy, offering sustainable process and recovery options to support life cycle assessment.

Maier P., Kammrath Betancor P., Reinhard T.

Sahoo J., Krishnaraj C., Sun J., Bihari Panda B., Subramanian P.S., Sekhar Jena H.

• Wide range of coordination complexes containing lanthanide ions are discussed as luminescent probes for phosphate ions and derivatives. • Lanthanide modified carbon dots, quantum dots and polyoxometalates as luminescent probes for phosphate sensing are also highlighted. • The photophysical properties of lanthanide systems in presence of phosphate ions and nucleoside phosphates are discussed. • Effect of different set of ligands (mixed, cyclen, N-containing and carboxylate) on the luminescent mechanisms are highlighted. • A future perspectives, highlighting important points for the designing and fabricating future sensor is also discussed. Over past 15 years, lanthanide complexes have been studied in a wide range of different field of applications including biological, environmental, pharmaceuticals and etc. This review gives an introduction on how to design luminescent lanthanide complexes and use them as biological phosphate sensor e.g. phosphate ions (Pi) and phosphate containing compunds (PPi, ATP, ADP, AMP). Phosphate ions and derivatives are important for environment, health and safety, therefore their detection and removal are remain challenging. The scope of this review covers wide range of lanthanide based coordination complexes containing ligands with mixed coordination sites or mixed ligands, cyclen based ligands and N-based heterocycles, lanthanide based helicates, lanthanide modified polyoxometallates, carbon dots and quantum dots, coordination polymers and metal organic frameworks as luminescent probe for phosphate and phosphate containing compounds sensing. The role of organic linkers or building units in the energy transfer process (turn on/off) are highlighted and most important and recent examples are discussed in detail while. A conclusion is provided discussing the future perspectives of lanthanides based luminescent probes for phosphate sensing.

Fayzullin A., Vladimirov G., Kuryanova A., Gafarova E., Tkachev S., Kosheleva N., Istranova E., Istranov L., Efremov Y., Novikov I., Bikmulina P., Puzakov K., Petrov P., Vyazankin I., Nedorubov A., et. al.

AbstractOne of the severe complications occurring because of the patient’s intubation is tracheal stenosis. Its incidence has significantly risen because of the COVID-19 pandemic and tends only to increase. Here, we propose an alternative to the donor trachea and synthetic prostheses—the tracheal equivalent. To form it, we applied the donor trachea samples, which were decellularized, cross-linked, and treated with laser to make wells on their surface, and inoculated them with human gingiva-derived mesenchymal stromal cells. The fabricated construct was assessed in vivo using nude (immunodeficient), immunosuppressed, and normal mice and rabbits. In comparison with the matrix ones, the tracheal equivalent samples demonstrated the thinning of the capsule, the significant vessel ingrowth into surrounding tissues, and the increase in the submucosa resorption. The developed construct was shown to be highly biocompatible and efficient in trachea restoration. These results can facilitate its clinical translation and be a base to design clinical trials. Graphical Abstract

Martinon T.L., Pierre V.C.

Inorganic and organic phosphates-including orthophosphate, nucleotides, and DNA-are some of the most fundamental anions in cellular biology, regulating numerous processes of both medical and environmental significance. The characteristic long lifetimes of emitting lanthanides, including the brighter europium(III) and terbium(III), make them ideally suited for the development of molecular probes for the detection of phosphates directly in complex aqueous media. Moreover, given their high oxophilicity and the exquisite sensitivity of their quantum yields to their hydration number, those luminescent lanthanides are perfect for the detection of phosphates. Herein we discuss the principles that have guided the recent developments of molecular probes selective for inorganic or organic phosphates and how these lanthanide complexes facilitate the study of numerous biological processes.

Kaufman A.R., Tu E.Y.

Acanthamoeba keratitis (AK) is a severe cause of infectious keratitis and represents a significant clinical challenge. Recent literature regarding AK epidemiology , diagnosis, treatment modalities, and prognosis is reviewed and synthesized to propose an algorithmic protocol for AK management. Globally, AK outbreaks in developed countries are ongoing, and AK rates have increased. Moreover, current outbreaks may carry a worse prognosis than prior outbreaks. Despite identification of contact lens solutions implicated in AK outbreaks and the consequent market recall of these products, outbreaks persist. Acanthamoeba keratitis afflicts not only refractive soft contact lens users but also cosmetic contact lens users and gas permeable (especially orthokeratology) lens users. Innovations in in vivo confocal microscopy and PCR assays have increased the role for these adjuvant tests alongside corneal smear and culture in a multimodal diagnostic approach to suspected AK. Biguanides (such as chlorhexidine and polyhexamethylene biguanide) and diamidines (propamidine isethionate and hexamidine) remain cornerstones of AK management, and evidence for other treatment modalities continues to evolve. Voriconazole in topical and systemic forms may be useful as adjuvant therapy . The anti-leishmaniasis drug miltefosine , recently given orphan drug status by the United States Food and Drug Administration, has increasing evidence supporting a role in patients with severe/refractory disease. Prior topical corticosteroids have been consistently shown to be associated with worse outcomes in AK. Although not historically thought of as a treatment modality, benzalkonium chloride preservative may be leveraged for its anti- Acanthamoebal properties. The role of Rose-Bengal photodynamic antimicrobial therapy is evolving in selected cases of AK.

Rodina E.S., Chebotar I.V., Kravchik M.V., Lyamin A.V., Fetser E.I., Zaitsev A.V., Novikov I.A.

Relevance. In modern ophthalmology, for the diagnosis of inflammatory diseases of the ocular surface, a new technique is needed that allows significantly reducing the study time, increasing the informative value of visual data. Scanning electron microscopy can become such a method, provided that a determinant atlas is created with a set of reference cultures for preliminary identification of microorganisms detected on the ocular surface. Purpose. The purpose of our study is to create an atlas of microorganisms, samples of which were prepared by the method of lanthanide contrast for SEM. Material and methods. We used cultures of microorganisms of the following species Achromobacter xylosoxidans, Acinetobacter baumannii, Bacillus cereus, Burkholderia cepacia, Corinebacterium diphthereae, Escherichia coli, Klebsiella pneumoniae, Moraxella catarhalis, Pseudomonas aeruginosa, Rothia mucilaginosa, Salmonella enterica, Serratia marcescens, Shigella sonnei, Staphylococcus aureus, Staphylococcus epidermidis, Stenotrophomonas maltophilia, Streptococcus pneumoniae, Candida albicans, Pneumocystis jirovecii, Mycobacterium abscessus. Samples of reference cultures of microorganisms were prepared by the method of lanthanide contrast for SEM. Further, the obtained images of microorganisms were used to compile illustrations of the atlas and analyze the features that are conservative for the defined groups. Results and discussions. 45 images were obtained with a standard resolution of 58.1 nm/px at 1024x768 px and 452 images with a standard resolution of 21 nm/px at 1024x768 px. Preliminary data of typing indicate that with the help of the proposed atlas-determinant, a satisfactory diagnosis up to the genus-level clusters is possible. Conclusion. The atlas with illustrations of reference cultures, the most common microorganisms on the ocular surface, will be the first step for the introduction of a new technique as an express diagnosis of infectious diseases of the eye. Keywords: scanning electron microscopy, lanthanide contrast, rapid diagnostic method, inflammatory diseases of the ocular surface.