Acid Sensitive Ion Channels as Target of Hydrogen Sulfide in Rat Trigeminal Neurons

© 2016, Springer Science+Business Media New York.Hydrogen sulfide (H2S), an endogenous gasotransmitter, was proposed to act as a signaling molecule in a wide variety of pathophysiological processes including inflammation and nociception. Acid-sensing ion channels (ASICs) are voltage-insensitive, proton-gated cation channels activated by extracellular acidosis, and are involved in various pathologies of the nervous system including ischemia, stroke, and migraine. In this study, the effect of the H2S donor-sodium hydrogen sulfide (NaHS) on the firing of trigeminal (TG) nerve was explored using suction electrode recordings in peripheral branches of the TG nerve in isolated rat meninges, and patch clamp recordings of ASIC currents in isolated TG neurons. NaHS (100 μM) increased the action potential frequency of TG nerve and bath application of NaHS increased the amplitude of ASIC currents triggered by focal application of low pH solution on isolated TG neurons. We propose that activation of ASICs by H2S during chronic inflammation process contributes to the increased excitability of the TG system and may be implicated in the generation of nociceptive firing underlying migraine pain

Hydration number: Crucial role in nuclear magnetic relaxivity of Gd(III) chelate-based nanoparticles

© 2017 The Author(s). Today, nanostructure-based contrast agents (CA) are emerging in the field of magnetic resonance imaging (MRI). Their sensitivity is reported as greatly improved in comparison to commercially used chelate-based ones. The present work is aimed at revealing the factors governing the efficiency of longitudinal magnetic relaxivity (r 1 ) in aqueous colloids of core-shell Gd(III)-based nanoparticles. We report for the first time on hyd ration number (q) of gadolinium(III) as a substantial factor in controlling r 1 values of polyelectrolyte-stabilized nanoparticles built from water insoluble complexes of Gd(III). The use of specific complex structure enables to reveal the impact of the inner-sphere hydration number on both r 1 values for the Gd(III)-based nanoparticles and the photophysical properties of their luminescent Tb(III) and Eu(III) counterparts. The low hydration of TTA-based Gd(III) complexes (q ≈ 1) agrees well with the poor relaxivity values (r 1 = 2.82 mM -1 s -1 and r 2 = 3.95 mM -1 s -1 ), while these values tend to increase substantially (r 1 = 12.41 mM -1 s -1 , r 2 = 14.36 mM -1 s -1 ) for aqueous Gd(III)-based colloids, when macrocyclic 1,3-diketonate is applied as the ligand (q ≈ 3). The regularities obtained in this work are fundamental in understanding the efficiency of MRI probes in the fast growing field of nanoparticulate contrast agents

PROSPECTS OF USING A BIOGAS PLANT FOR THE UTILIZATION OF ORGANIC WASTE FROM POULTRY FARMS

The paper considers the issue of organizing the optimal process of waste disposal at a poultry farm in an ecological way. Also, the benefits of biogas plant building are considered and the reasons for its necessity from an environmental point of view are represented.В работе рассматривается вопрос организации оптимального процесса утилизации органических отходов на птицефабрике. Рассмотрен экологический аспект применения биогазовой установки, представлены основные преимущества и недостатки

Receptor mechanisms mediating the pro-nociceptive action of hydrogen sulfide in rat trigeminal neurons and meningeal afferents

© 2017 Koroleva, Mustafina, Yakovlev, Hermann, Giniatullin and Sitdikova. Hydrogen sulfide (H 2 S), a well-established member of the gasotransmitter family, is involved in a variety of physiological functions, including pro-nociceptive action in the sensory system. Although several reports have shown that H 2 S activates sensory neurons, the molecular targets of H 2 S action in trigeminal (TG) nociception, implicated in migraine, remains controversial. In this study, using suction electrode recordings, we investigate the effect of the H 2 S donor, sodium hydrosulfide (NaHS), on nociceptive firing in rat meningeal TG nerve fibers. The effect of NaHS was also explored with p atch-clamp and calcium imaging techniques on isolated TG neurons. NaHS dramatically increased the nociceptive firing in TG nerve fibers. This effect was abolished by the TRPV1 inhibitor capsazepine but was partially prevented by the TRPA1 blocker HC 030031. In a fraction of isolated TG neurons, NaHS transiently increased amplitude of capsaicin-induced currents. Moreover, NaHS by itself induced inward currents in sensory neurons, which were abolished by the TRPV1 inhibitor capsazepine suggesting involvement of TRPV1 receptors. In contrast, the inhibitor of TRPA1 receptors HC 030031 did not prevent the NaHS-induced currents. Imaging of a large population of TG neurons revealed that NaHS induced calcium transients in 41% of tested neurons. Interestingly, this effect of NaHS in some neurons was inhibited by the TRPV1 antagonist capsazepine whereas in others it was sensitive to the TRPA1 blocker HC 030031. Our data suggest that both TRPV1 and TRPA1 receptors play a role in the pro-nociceptive action of NaHS in peripheral TG nerve endings in meninges and in somas of TG neurons. We propose that activation of TRPV1 and TRPA1 receptors by H 2 S during neuro-inflammation conditions contributes to the nociceptive firing in primary afferents underlying migraine pain

Improving the information system of university management

© 2015, Canadian Center of Science and Education. All rights reserved. University management is currently supported by information system providing storage and data structuring of information required. Managing the development and improvement of the educational process quality requires creation of a monitoring system covering all of its objects and various measurement tools, which monitors the set of all features. The paper presents the components of pedagogical management, considers indicators of pedagogical processes and methods of evaluation, which define the basis for monitoring the educational processes at the University. Also the structure of a software module is shown, that works on the principle of the expert system and identifies problem characteristics of the educational activity. The results of the experimental work show the effectiveness of the presented software, that supports management decision-making of university departments’ leadership and faculty

Methylviologen-mediated electrochemical synthesis of platinum nanoparticles in solution bulk

© 2017, Pleiades Publishing, Ltd.Platinum nanoparticles (PtNPs) are synthesized by methylviologen-mediated reduction of PtCl2 at the potentials of the MV2+/MV•+ redox couple in 40% aqueous DMF solution. In the absence of stabilizing agents and in the presence of a stabilizer in the form of spherical silica NPs or alkylamine-modified silica NPs (SiO2-NHR), a part of PtNPs (14–18%) are deposited on the electrode while the rest of particles remain in solution to form coarse aggregates which precipitate. In the latter case, PtNPs are also partly bound to form individual ultrafine NPs (3 ± 2 nm) on the SiO2-NHR surface. In the presence of polyvinylpyrrolidone (PVP), the generated PtNPs (18 ± 9 nm) neither aggregate nor deposit on the cathode but are completely stabilized in solution being encapsulated within the PVP matrix. The obtained PtNPs are characterized by the methods of dynamic light-scattering and electron microscopy

Structure impact in antenna effect of novel upper rim substituted tetra-1,3-diketone calix[4]arenes on Tb(III) green and Yb(III) NIR-luminescence

© 2016 Elsevier Ltd.Two novel calix[4]arene macrocyclic ligands functionalized with four 1,3-diketone groups at the upper and hydroxyl (3) or propyloxy-groups (6) at the lower rims were synthesized and characterized using NMR, IR spectroscopy, mass spectrometry, and elemental analysis. UV-vis spectrophotometry and ESI mass spectrometry studies indicate 1:1 complex formation of ligands 3 and 6 with Ln(III) (Ln=Tb, Yb) in alkaline DMF solutions resulted from coordination of Ln(III) with 1,3-diketonate groups. Luminescence study of Ln(III) complexes with 3 and 6 reveals significant difference in antenna effects of their deprotonated forms on both Tb(III)- and Yb(III)-centered luminescence. Comparison of ligand-centered emission for ligands 3 and 6 points to the latter as more efficient antenna for Tb(III) and Yb(III). Different conformational behavior of ligands 3 and 6 in alkaline media is assumed as a reason for the experimentally observed difference in sensitization pathways in Ln(III) complexes with 3 and 6

АМПЕРОМЕТРИЧЕСКИЕ ИММУНОСЕНСОРЫ НА ОСНОВЕ УГЛЕРОДНЫХ НАНОМАТЕРИАЛОВ И КЛАСТЕРОВ РЕНИЯ ДЛЯ ОПРЕДЕЛЕНИЯ ТРИЦИКЛИЧЕСКИХ АНТИДЕПРЕССАНТОВ В ПОСЛЕДОВАТЕЛЬНОЙ ИНЖЕКЦИОННОЙ СИСТЕМЕ

A method of sequential injection determination of tricyclic antidepressants (amitriptyline, desipramine, imipramine) using amperometric immunosensors based on screen-printed graphite electrodes modified by carbon nanomaterials (carbon nanotubes, graphene oxide or fullerene) in combination with hexarhenium chalcogenide clusters is proposed. Sequential injection analysis was performed at a sweep rate of 10 mV/s; the flow rate (supporting electrolyte – phosphate buffer solution with pH 7.0) was also varied from 20 to 40 µl/s. Composition of the modifier affects the analytical capability of immunosensors. Screening of various types of modifiers showed that the immunosensor based on graphene oxide and cyanide complexes of rhenium chalcogenide clusters exhibited the highest sensitivity of 23.9±0.9 with a range of working concentrations of 1·10–10–1·10–5 M, and even wider range of detectable concentrations, 1·10–10–1·10–4 M was observed for the immunosensor based on fullerene and cyanide complexes of rhenium chalcogenide clusters. The lowest limit of the determined contents was (4–7)·10–11 M. Relative standard deviation of repeatability (Sr) did not exceed 0.046. The results obtained show that the proposed immunosensors can be used in sequential injection determination of trace amounts of medicinal compounds (antidepressants) in biomedical objects.Keywords: immunosensor, carbon nanomaterials, hexarhenium chalcogenide clusters, tricyclic antidepressants, sequential injection analysisПредложен способ последовательного инжекционного определения трициклических антидепрессантов (амитриптилин, дезипрамин, имипрамин) с использованием амперометрических иммуносенсоров на основе печатных графитовых электродов, модифицированных углеродными наноматериалами (углеродные нанотрубки, оксид графена или фуллерен) в сочетании с гексарениевыми халькогенидными кластерами. Последовательный инжекционный анализ проводили при скорости развертки 10 мВ/с, также варьировали скорость потока (фоновый электролит - фосфатный буферный раствор с рН 7.0) от 20 до 40 мкл/с. Состав модификатора оказывает влияние на аналитические возможности иммуносенсоров. Скрининг различных вариантов модификаторов показал, что наибольшая чувствительность 23.9 ± 0.9 с диапазоном рабочих концентраций 1 ·10-10 – 1 · 10-5 М характерна для иммуносенсора на основе оксида графена и цианидных комплексов халькогенидных кластеров рения, а более широкая область определяемых содержаний 1 · 10-10 – 1 · 10-4 М наблюдается в случае иммуносенсора на основе фуллерена и цианидных комплексов халькогенидных кластеров рения. Нижняя граница определяемых содержаний находится на уровне (4 – 7)·10-11 М.Относительное стандартное отклонение повторяемости (Sr) не более 0.046. Полученные результаты показывают, что предлагаемые иммуносенсоры могут найти применение в последовательном инжекционном определении следовых содержаний лекарственных соединений (антидепрессантов) в медико-биологических объектах.Ключевые слова: иммуносенсор, углеродные наноматериалы, гексарениевые халькогенидные кластеры, трициклические антидепрессанты, последовательный инжекционный анали

Alkyl-malonate-substituted thiacalix[4]arenes as ligands for bottom-up design of paramagnetic Gd(III)-containing colloids with low cytotoxicity

© 2017 The Authors. The present work introduces thiacalix[4]arene adopting 1,3-alternate conformation with alkyl-malonate terminal substituents as ligands for Gd(III) ions. pH-dependent complex formation of Gd(III) ions via alkyl-malonate substituents in aqueous DMSO solutions results in a precipitation. The precipitated complexes were converted into hydrophilic colloids of "plum-pudding" morphology, where the Gd(III) complexes form hard small (1.5-4nm) cores included into larger (about 180nm) soft PSS shells. The precipitate-to-colloid transformation is facilitated by polystyrolsulfonate (PSS) for Gd(III) complexes with thiacalix[4] arene bearing propyl-malonate groups, while the presence of PSS triggers a dissolution of the precipitated complexes for thiacalix[4]arenes with pentyl-malonate substituents. To a lesser extent the similar tendency disturbs the formation of PSS-stabilized colloids on the basis of butyl-malonate substituted thiacalix[4] arene. The PSS-stabilized colloids exhibit high longitudinal and transverse relaxivities (r 1 =23.8 and r 2 =29.4mM -1 s -1 at 0.47T, respectively), while the recoating of the PSS-stabilized colloids with polyethyleneimine is accompanied by the dissolution of the hard cores. High relaxivity along with low cytotoxicity of PSS-stabilized colloids indicates their applicability as contrast agents in MRI

High performance magneto-fluorescent nanoparticles assembled from terbium and gadolinium 1,3-diketones

© The Author(s) 2017.Polyelectrolyte-coated nanoparticles consisting of terbium and gadolinium complexes with calix[4]arene tetra-diketone ligand were first synthesized. The antenna effect of the ligand on Tb(III) green luminescence and the presence of water molecules in the coordination sphere of Gd(III) bring strong luminescent and magnetic performance to the core-shell nanoparticles. The size and the core-shell morphology of the colloids were studied using transmission electron microscopy and dynamic light scattering. The correlation between photophysical and magnetic properties of the nanoparticles and their core composition was highlighted. The core composition was optimized for the longitudinal relaxivity to be greater than that of the commercial magnetic resonance imaging (MRI) contrast agents together with high level of Tb(III)-centered luminescence. The tuning of both magnetic and luminescent output of nanoparticles is obtained via the simple variation of lanthanide chelates concentrations in the initial synthetic solution. The exposure of the pheochromocytoma 12 (PC 12) tumor cells and periphery human blood lymphocytes to nanoparticles results in negligible effect on cell viability, decreased platelet aggregation and bright coloring, indicating the nanoparticles as promising candidates for dual magneto-fluorescent bioimaging