Динамика гибели ганглиозных клеток сетчатки при глаукоме и ее функциональные маркеры

The review presents various aspects of structural and functional disorders of the visual system in humans and experimental animals associated with physiological involution and the development of glaucoma, which are organized by visual structures and types of change. Particular attention is given to alterations of retinal ganglion cells (RGC). Age-related changes in the RGCs and their central projections are compared with changes occurring in glaucoma. Literature data on the sequence of events occurring in RGC death, including changes in the inner plexiform layer of the retina (the dendritic and synaptic plasticity, reduction of the complexity of dendritic branching and degeneration of the processes), dysfunction and degeneration, a change in the morphology and apoptosis of RGC soma are discussed in the review. The problem of the sensitivity of axons and dendrites of the RGC for a variety of cell types (belonging to parvocellular and magnocellular systems) and their subclasses (on-, off- and on-off-cells) is analyzed. A comparative analysis of the possibilities of modern technologies in perimetry, structural imaging of the retina and electrophysio-logical studies in the diagnostics of primary glaucoma and their prospects in the context is presented. The necessity to standardize a set of parameters of functional and morphological examinations to identify early stages of RGC death in glaucoma patients and patients with suspected POAG is substantiated. Such a set of parameters would allow an adequate assessment changes in dendritic processes, axon dysfunction and degeneration as well as soma death, facilitating a timely and adequate choice of targeted therapy.В аналитическом обзоре представлены различные аспекты нарушения структуры и функции зрительной системы у человека и экспериментальных животных при физиологической инволюции и развитии глаукомы, которые систематизированы по зрительным структурам и типам изменений. Особое внимание уделено альтерациям самих ганглиозных клеток (ГК) сетчатки. Возрастные изменения ГК сетчатки и их центральных проекций сопоставлены с изменениями, происходящими при глаукоме. Анализируются данные литературы о последовательности событий, происходящих при гибели ГК, включая изменения во внутреннем плексиформном слое сетчатки (дендритная и синаптическая пластичность, нарушение сложности дендритного ветвления и дегенерация отростков), дисфункцию и дегенерацию аксонов ГК, изменение морфологии и апоптоз сомы ГК. Рассматривается вопрос о чувствительности аксонов и дендритов ГК для различных клеточных типов (принадлежащих парво- и магноцеллюлярной системам) и подклассов (on-, off- и on-off-клеток). Дан сравнительный анализ возможностей современных технологий периметрии, структурной визуализации сетчатки и электрофизиологических исследований в диагностике начальной глаукомы и их перспективы в свете обсуждаемой проблемы. Обосновывается необходимость стандартизировать комплекс параметров функциональных и морфологических исследований для идентификации различных этапов гибели ГК у глаукомных больных и у лиц с подозрением на ПОУГ, которые будут адекватно отражать изменения дендритных отростков, дисфункцию и дегенерацию аксонов и гибель сомы, способствуя своевременному и адекватному выбору таргетной терапии

Plants of the calcifilic flora exposition of the N.V. Tsitsin Main Botanical Garden of the Russian Academy of Sciences, listed in the regional Red Data Books of Central Russia

The results of conservation of plants of the exposition of the calciphilous flora of the Main Botanical Garden of the Russian Academy of Sciences, listed in the regional Red Data Books of Central Russia, are shown. For 12 years, in the culture of GBS RAS, in the conditions of Moscow, 118 calciphilous species listed in the regional Red Books, represented by 77 genera from 34 families, were studied. Among them, in terms of introduction resistance, resistant ones prevail - 46% and highly resistant - 35.5%, weakly resistant - 13.5%, unstable - 5%. The main groups according to ecological confinement are considered: obligate (25%) and facultative (75%) calciphilic species. The experiment proved the importance of using special agricultural techniques for the successful adaptation of representatives of this group. In total, an average of 70% of calciphilous taxa of regional protected lists were tested. The representation of calciphilic species in the regional Red Data Books of Central Russia is different and is due to the natural features of the distribution of their classical habitats. In the regions of the Chernozem region, this figure ranges from 55% in the Belgorod region to 24% in the Tambov region. In the Non-Chernozem region: Bryansk, Ryazan, Tula regions, calciphilic species in relation to the total number of protected species also represent a significant part - 25%. For Vladimir, Ivanovo, Kaluga, Kostroma, Smolensk, Tver, Yaroslavl regions and the federal city of Moscow, calciphilic taxa represent an average of 9% of protected lists. The share of calciphilous species of categories: 0, 1, 2 in the regional Red Data Books of Central Russia averages 58%, which indicates a high vulnerability of this group and the need for ex situ stud

High-spin Fe(III) Schiff based complexes with photoactive ligands. Synthesis, EPR study and magnetic properties

© 2018 Elsevier Ltd A series of three novel Fe(III) compounds of the formula [FeL2]X (where X = Cl− (1), PF6− (2), NO3– (3), and L is a photoactive ligand, (4)-4-(((2-(ethylamino)ethyl)imino)methyl)-3-hydroxyphenyl 4-bromobenzoate) was synthesized and studied by means of electron paramagnetic resonance (EPR) and pulsed laser irradiation. The Fe3+ ions in these compounds are in a high-spin state. A thorough analysis of the EPR data suggests that compounds 1 and 2 undergo an order–disorder ferroelectric phase transition, and below the phase transition temperature (Tc = 100 and 200 K for compounds 1 and 2, respectively) a nonzero average electric dipole moment appears. To get an insight into molecular structure of Fe3+ ions and their supramolecular organization in low-temperature (LT) and high-temperature (HT) phases of compounds 1 and 2, a series of density functional theory calculations was performed. On the basis of our findings, the LT- and HT-phase structures were proposed for these compounds. It was also shown that, whereas the chloride and hexafluorophosphate anions are able to form a network of hydrogen bonds between the [FeL2]X units (ionic pairs), which enable an electric dipole ordering in the sample, the nitrate anions, in contrast, tend to form hydrogen bonds inside the ionic pair. This conclusion is evidenced by the observed EPR spectra, which are different for compound 3 and are not indicative of the existence of an order–disorder ferroelectric phase transition. The EPR data obtained upon irradiation of compound 1 show that photoexcitation in the UV region at 5 K destroys hydrogen bonds and converts cationic complexes into ligand-to-metal charge transfer (LMCT) states, in which the iron is ferrous, and the unpaired electron is located on the salicylidene moieties. The LMCT states decay back to the ferric one, and ferric complexes further form the most stable (LT) phase structure

Lease or easement for a forest plot for linear objects: An economic aspect

In this article, we will consider the interesting, in our opinion, presented data of practitioners and scientists in terms of the study of more cost-effective disposal of forest plots provided for linear objects on the lands of the forest fund of Russia. In our opinion, today it is quite relevant to resolve issues around the payment for the use of forest plots for linear objects for our country: granting the right to lease or establish an easement for the considered plots, as well as conducting forecast financial calculations of these options for the provision of land for 2020. In this article, we only showed forward-looking calculations on the example of the Ural Federal District, which has almost 10% of the country's forest land (almost 60% of the district's area), for conclusions about the damage to the budget due to lost revenue due to the choice of the form of granting forest plots, a more complete study of the economic mechanism of land management of the country is necessary, such a task the authors have not yet set themselves. © The Authors, published by EDP Sciences, 2021

ОСОБЕННОСТИ ПРОБОПОДГОТОВКИ ПРИ ОПРЕДЕЛЕНИИ ФЕНОЛА В ВЫСОКОЦВЕТНЫХ ПРИРОДНЫХ ВОДАХ МЕТОДОМ ГАЗОВОЙ ХРОМАТОГРАФИИ

Existing the phenol determination methods in water suggest the use of extraction concentration combined with heating the sample and phenol derivatization in alkaline media. It is shown that humic substances of water samples is destructed by the alkaline solutions or heating. Humic substances destruction produces phenol and distorts the results of quantitative chemical analysis. The interfering effect of humic substances need to be eliminate in beginning of the analytical cycle. A method for removing humus by coagulation on the Al2O3 layer with simultaneous impregnation of the sorbent with copper (II) cations is proposed. The method allows to eliminate the interfering effect of humic substances in the phenol quantification in natural waters. The conditions of humic substances complete removal from the water samples is established, the role of copper (II) cations in this process is shown. Under optimal conditions, the native phenol adsorption on alumina surface does not exceed 3 %. For selective and sensitive gas-chromatographic determination of phenol in the eluate we used preliminary bromination. Phenol bromoderivative (2,4,6-tribromophenol) with a halogen-selective electron-capture detector was detected. A procedure was developed for phenol determination in water of 0.2 to 10 μg/dm3, the relative error of measurement in this range does not exceed 30 %. The water sample volume is 25 cm3, the analysis duration is 30 min.Keywords: phenol, gas chromatography, high-color natural water, chemical modification, humic substances, aluminum oxideDOI: http://dx.doi.org/10.15826/analitika.2019.23.2.004(Russian)I.V. Gruzdev, B.M. Kondratenok, O.M. Zueva, E.I. Lyu-Lyan-Min Institute of Biology of Komi Scientific Centre of the Ural Branch of the Russian Academy of Sciences (IB Komi SC UB RAS), Kommunisticheskaya st., 28, Syktyvkar, 167982, Russian FederationРяд методик определения фенольных соединений в водных средах предполагает использование в аналитическом цикле экстракционного концентрирования в сочетании с нагреванием пробы и проведение реакций дериватизации в щелочных средах. Показано, что такие операции, проводимые в присутствии гумусовых веществ, вызывают их деструкцию с образованием фенола. Предложен способ удаления гумуса путем коагуляции на слое Al2O3 при одновременном импрегнировании сорбента катионами меди (II). Способ позволяет устранить мешающее влияние гумусовых веществ при количественном определении фенола в природных водах. Установлены условия, при которых достигается полное удаление гумусовых веществ из анализируемой пробы воды, показана роль катионов меди в этом процессе. При установленных оптимальных условиях адсорбция нативного фенола на оксиде алюминия не превышает 3 %. С целью повышения чувствительности и селективности определения фенола в получаемом элюате проводится его химическая модификация в 2,4,6-трибромфенол с последующим газохроматографическим анализом с галогенселективным электронозахватным детектором. Диапазон определяемых концентраций фенола в воде от 0.2 до 10 мкг/дм3 с относительной погрешностью не более 30 %. Объем пробы воды, необходимый для анализа, – 25 см3, продолжительность анализа – 30 минут.Ключевые слова: фенол, газовая хроматография, высокоцветные природные воды, химическая модификация, гумусовые вещества, оксид алюминияDOI: http://dx.doi.org/10.15826/analitika.2019.23.2.00

Counterion effect on the spin-transition properties of the second generation iron(III) dendrimeric complexes

© 2017 Elsevier B.V.The magnetic properties and the influence of counterions on the spin crossover properties of two novel Fe(III) dendrimeric complexes of the second generation, namely [Fe(L)2]+X−, where L = 3,5-di(3,4,5-tris(tetradecyloxy)benzoyloxy)benzoyl-4-oxy-salicylidene-N’-ethyl-N-ethylenediamine X = Cl− (1), ClO4− (2), have been studied for the first time by magnetic susceptibility measurements and electron paramagnetic resonance (EPR) method in a wide (4.2–300 K) temperature range. EPR results showed that compound 1 contains about 98% of high-spin (HS, S = 5/2) and ∼2% of low-spin (LS, S = 1/2) Fe(III) centers, and undergoes an antiferromagnetic ordering below 7 K. The EPR integrated intensity of a broad line (g ≈ 2), corresponding to the HS iron(III) centers, passes through a broad maximum at Tmax ≈ 100 K, which is indicative of short-range correlation effects. The anomalous broadening of this EPR line at low temperatures with the critical exponent β = 1.5 upon approaching the long-range ordering transition (TNEPR = 7 K) from above indicates the quasi-two-dimensional antiferromagnetic nature of magnetism in complex 1. The spin-crossover effect is completely suppressed in compound 1. The complex with ClO4− counterion demonstrates a different magnetic behavior. EPR data showed that compound 2 contains about 77% of LS and ∼23% of HS Fe(III) centers at TNEPR = 10.2 K. It displays a partial spin crossover (S = 5/2 ↔ 1/2) above 150 K and undergoes the antiferromagnetic ordering below 10.2 K. The obtained results and the results of DFT calculations allowed us to conclude that a bilayered packing with a chain structure of Fe(III) centers in ionic bilayers is formed in compound 1, whereas a dimeric structure of Fe(III) centers is formed in compound 2. Thus, the ability of the counterion to form an effective network of hydrogen bonds and its size define the packing motif of the [Fe(L)2]+ complexes. Therefore, the replacing of the counterion has a significant impact on the magnetic properties of the compound

STepwise Magnetic Behavior of the Liquid Crystal Iron(Iii) Complex

EPR and Mossbauer spectroscopy is used to study a new liquid crystal complex of iron(III) with a Schiff base: 4,4'S-dodecyloxybenzoyloxybenzoyl-4- oxysalicylidene-2-aminopyridine with a PF6'{ counterion. It is shown that Fe(III) ions exist only in the high-spin (HS, S = 5/2) state. It is found that under the influence of temperature the system demonstrates the stepwise behavior of the product of the integrated intensity of EPR lines (I ) and temperature (proportional to "where" is the magnetic susceptibility) with an inflection point at "80 K. Above 80 K a new EPR spectrum is detected due to the excited S = 2 state and the formation of dimeric molecules (through oxygen bridges) with a strong intramolecular antiferromagnetic exchange interaction J1 = 162.1 cm-V1. Below 80 K iron(III) complexes are organized in 1D chains where the exchange value J2 = 2.1 cm-V1. At 80 K there is a structural phase transition in the system: the transition from a 1D chain organization of HS Fe(III) centers to dimeric molecules. Based on quantum chemical calculations a model of the binuclear iron(III) complex is proposed. Copyright © 2013 by N. E. Domracheva, V. E. Vorob'eva, A. V. Pyataev, R. A. Manapov, E. M. Zueva, M. S. Gruzdev, U. V. Chervonova

Specific inhibition of acetylcholinesterase as an approach to decrease muscarinic side effects during myasthenia gravis treatment

© 2017 The Author(s). Non-selective inhibitors of cholinesterases (ChEs) are clinically used for treatment of myasthenia gravis (MG). While being generally safe, they cause numerous adverse effects including induction of hyperactivity of urinary bladder and intestines affecting quality of patients life. In this study we have compared two ChEs inhibitors, a newly synthesized compound C547 and clinically used pyridostigmine bromide, by their efficiency to reduce muscle weakness symptoms and ability to activate contractions of urinary bladder in a rat model of autoimmune MG. We found that at dose effectively reducing MG symptoms, C547 did not affect activity of rat urinary bladder. In contrast, at equipotent dose, pyridostigmine caused a significant increase in tonus and force of spontaneous contractions of bladder wall. We also found that this profile of ChEs inhibitors translates into the preparation of human urinary bladder. The difference in action observed for C547 and pyridostigmine we attribute to a high level of pharmacological selectivity of C547 in inhibiting acetylcholinesterase as compared to butyrylcholinesterase. These results raise reasonable hope that selective acetylcholinesterase inhibitors should show efficacy in treating MG in human patients with a significant reduction in adverse effects related to hyperactivation of smooth muscles

Slow-binding inhibition of acetylcholinesterase by an alkylammonium derivative of 6-methyluracil: Mechanism and possible advantages for myasthenia gravis treatment

© 2016 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.Inhibition of human AChE (acetylcholinesterase) and BChE (butyrylcholinesterase) by an alkylammonium derivative of 6-methyluracil, C-547, a potential drug for the treatment of MG (myasthenia gravis) was studied. Kinetic analysis of AChE inhibition showed that C-547 is a slow-binding inhibitor of type B, i.e. after formation of the initial enzyme•inhibitor complex (Ki = 140 pM), an induced-fit step allows establishment of the final complex (Ki = 22 pM). The estimated koff is low, 0.05 -1 . On the other hand, reversible inhibition of human BChE is a fast-binding process of mixed-type (Ki = 1.77 μM; Ki = 3.17 μM). The crystal structure of mouse AChE complexed with C-547 was solved at 3.13 Å resolution. The complex is stabilized by cation-π , stacking and hydrogenbonding interactions. Molecular dynamics simulations of the binding/dissociation processes of C-547 and C-35 (a noncharged analogue) to mouse and human AChEs were performed. Molecular modelling on mouse and human AChE showed that the slow step results from an enzyme conformational change that allows C-547 to cross the bottleneck in the active-site gorge, followed by formation of tight complex, as observed in the crystal structure. In contrast, the related non-charged compound C-35 is not a slow-binding inhibitor. It does not cross the bottleneck because it is not sensitive to the electrostatic driving force to reach the bottom of the gorge. Thus C-547 is one of the most potent and selective reversible inhibitors of AChE with a long residence time, τ; = 20 min, longer than for other reversible inhibitors used in the treatment of MG. This makes C-547 a promising drug for the treatment of this disease