Synthesis and Structure-Activity Relationships of Pyridoxal-6-arylazo-5'-phosphate and Phosphonate Derivatives as P2 Receptor Antagonists.

Novel analogs of the P2 receptor antagonist pyridoxal-5'-phosphate-6-phenylazo-2',4'-disulfonate (PPADS) were synthesized. Modifications were made through functional group substitution on the sulfophenyl ring and at the phosphate moiety through the inclusion of phosphonates, demonstrating that a phosphate linkage is not required for P2 receptor antagonism. Substituted 6-phenylazo and 6-naphthylazo derivatives were also evaluated. Among the 6-phenylazo derivatives, 5'-methyl, ethyl, propyl, vinyl, and allyl phosphonates were included. The compounds were tested as antagonists at turkey erythrocyte and guinea-pig taenia coli P2Y(1) receptors, in guinea-pig vas deferens and bladder P2X(1) receptors, and in ion flux experiments by using recombinant rat P2X(2) receptors expressed in Xenopus oocytes. Competitive binding assay at human P2X(1) receptors in differentiated HL-60 cell membranes was carried out by using [(35)S]ATP-?-S. A 2'-chloro-5'-sulfo analog of PPADS (C(14)H(12)O(9)N(3)ClPSNa), a vinyl phosphonate derivative (C(15)H(12)O(11)N(3)PS(2)Na(3)), and a naphthylazo derivative (C(18)H(14)O(12)N(3)PS(2)Na(2)), were particularly potent in binding to human P2X(1) receptors. The potencies of phosphate derivatives at P2Y(1) receptors were generally similar to PPADS itself, except for the p-carboxyphenylazo phosphate derivative C(15)H(13)O(8)N(3)PNa and its m-chloro analog C(15)H(12)O(8)N(3)ClPNa, which were selective for P2X vs. P2Y(1) receptors. C(15)H(12)O(8)N(3)ClPNa was very potent at rat P2X(2) receptors with an IC(50) value of 0.82 ?M. Among the phosphonate derivatives, [4-formyl-3-hydroxy-2-methyl-6-(2-chloro-5-sulfonylphenylazo)-pyrid-5-yl]methylphosphonic acid (C(14)H(12)-O(8)N(3)ClPSNa) showed high potency at P2Y(1) receptors with an IC(50) of 7.23 ?M. The corresponding 2,5-disulfonylphenyl derivative was nearly inactive at turkey erythrocyte P2Y(1) receptors, whereas at recombinant P2X(2) receptors had an IC(50) value of 1.1 ?M. An ethyl phosphonate derivative (C(15)H(15)O(11)N(3)PS(2)Na(3)), whereas inactive at turkey erythrocyte P2Y(1) receptors, was particularly potent at recombinant P2X(2) receptors

Protective Allele for Multiple Sclerosis HLA-DRB1*01:01 Provides Kinetic Discrimination of Myelin and Exogenous Antigenic Peptides.

Risk of the development of multiple sclerosis (MS) is known to be increased in individuals bearing distinct class II human leukocyte antigen (HLA) variants, whereas some of them may have a protective effect. Here we analyzed distribution of a highly polymorphous HLA-DRB1 locus in more than one thousand relapsing-remitting MS patients and healthy individuals of Russian ethnicity. Carriage of HLA-DRB1*15 and HLA-DRB1*03 alleles was associated with MS risk, whereas carriage of HLA-DRB1*01 and HLA-DRB1*11 was found to be protective. Analysis of genotypes revealed the compensatory effect of risk and resistance alleles in trans. We have identified previously unknown MBP153−161 peptide located at the C-terminus of MBP protein and MBP90−98 peptide that bound to recombinant HLA-DRB1*01:01 protein with affinity comparable to that of classical antigenic peptide 306-318 from the hemagglutinin (HA) of the influenza virus demonstrating the ability of HLA-DRB1*01:01 to present newly identified MBP153−161 and MBP90−98 peptides. Measurements of kinetic parameters of MBP and HA peptides binding to HLA-DRB1*01:01 catalyzed by HLA-DM revealed a significantly lower rate of CLIP exchange for MBP153−161 and MBP90−98 peptides as opposed to HA peptide. Analysis of the binding of chimeric MBP-HA peptides demonstrated that the observed difference between MBP153−161, MBP90−98, and HA peptide epitopes is caused by the lack of anchor residues in the C-terminal part of the MBP peptides resulting in a moderate occupation of P6/7 and P9 pockets of HLA-DRB1*01:01 by MBP153−161 and MBP90−98 peptides in contrast to HA308−316 peptide. This leads to the P1 and P4 docking failure and rapid peptide dissociation and release of empty HLA-DM–HLA-DR complex. We would like to propose that protective properties of the HLA-DRB1*01 allele could be directly linked to the ability of HLA-DRB1*01:01 to kinetically discriminate between antigenic exogenous peptides and endogenous MBP derived peptides

Detrusor overactivity induced by intravesical application of adenosine 5 '-triphosphate under different delivery conditions in rats

Objectives. We investigate the effects of intravesical application of adenosine 5'-triphosphate (ATP) on bladder activity to elucidate the role of urothelial barrier function and ecto-ATPase activity in the ATP-mediated mechanism inducing detrusor overactivity. Methods. Continuous cystometry by an intravesical catheter inserted from the bladder dome was performed in conscious female rats. Results. ATP solutions adjusted to pH 6.0 did not elicit significant detrusor overactivity at a concentration of 60 mM. However, in bladders pretreated with protamine sulfate (10 mg/mL) to increase urothelial permeability, ATP solution (pH 6.0) induced detrusor overactivity by decreasing the intercontraction intervals. These irritant effects of ATIP after protamine treatment were antagonized by P2X receptor antagonists, such as pyridoxal-5-phosphate-6-azophenyl-2',4-disulfonic acid (70 mu mol/kg) and 2',3'-O-(2,4,6, trinitrophenyl) ATP (30 mu mol/kg). These were also suppressed in rats pretreated with systemic capsaicin (125 mg/kg subcutaneously). Alpha,beta-methylene ATP (5 mM, pH 6.0) or ATP (60 mM, pH6) after intravesical infusion of 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (5 mM, pH 6.0), an ecto-ATPase inhibitor, induced detrusor overactivity without protamine pretreatment, but the reduction in intercontraction intervals was smaller compared with that with ATP after protamine treatment. Conclusions. Low permeability of bladder epithelium and ecto-ATPase activity can prevent ATP activation of subepithelial P2X receptors to induce bladder overactivity. Thus, enhanced penetration of endogenous ATIP owing to urothelial damage may contribute to urinary frequency and bladder pain in hypersensitive bladder disorders such as interstitial cystitis.</p

Temperature-Dependent Effects of ATP on Smooth and Skeletal Muscles

ATP acting via different subtypes of P2X and P2Y receptors induces contractions or relaxation of mammalian smooth muscles, while in skeletal muscles, ATP can pre- and postsynaptically modulate effect of acetylcholine. It was shown that effects of ATP on both types of the muscle are significantly changed when the temperature shifts from physiological condition. For example, contractile responses of rodent urinary bladder and vas deferens mediated by P2X receptors are markedly increased with the decrease of the temperature. Similarly, in frog skeletal muscles, ATP-induced inhibition of acetylcholine release became more pronounced at low temperatures. In case of mammalian skeletal muscle, effect of temperature on ATP-induced responses depends on the type of muscle—slow and fast. In this chapter, we will discuss temperature-dependent effects of ATP on different muscle contractility and their possible mechanisms

Neural network analysis of vibration signals in the diagnostics of pipelines

The article is devoted to the improvement of heat network calculation and diagnostics methods. Currently used instruments have many shortcomings for the diagnosis of pipelines, including low reliability of defect detection and subjective decision-making. The authors created an experimental stand, which allows to conduct the diagnostics of pipelines by a vibration-acoustic method. They studied steel pipes filled with water, the surface of which 50x50 mm defect and the depth of thinning of 2 mm, 3 mm, and 5 mm. Using the vibrationacoustic sensors fixed on an outer surface, the vibration signals generated by the water flow in the pipe were obtained. In order to process the large volumes of data obtained as the result of experiments, it is proposed to use artificial neural networks. Among all considered types of neural networks, the authors prefer Kohonen's networks due to the best effectiveness of a defect determination. The program for an acoustic signal processing and analyzing through a neural network was implemented in LabView 8.5 work environment. Depending on the accuracy of a problem being solved, and the details of a training sample, the program is able to produce the results of sample classification of samples for a defect-free and defective pipes of different depth of damage. The results of the classification by Kohonen's trained neural network show good abilities for the analysis of unknown samples and a high degree of their recognition reliability.Keywords: diagnosis, corrosion, defect, pipelines, acoustic signal, neural networ

A Novel Microwave Sensor to Detect Specific Biomarkers in Human Cerebrospinal Fluid and Their Relationship to Cellular Ischemia During Thoracoabdominal Aortic Aneurysm Repair

Thoraco-abdominal aneurysms (TAAA) represents a particularly lethal vascular disease that without surgical repair carries a dismal prognosis. However, there is an inherent risk from surgical repair of spinal cord ischaemia that can result in paraplegia. One method of reducing this risk is cerebrospinal fluid (CSF) drainage. We believe that the CSF contains clinically significant biomarkers that can indicate impending spinal cord ischaemia. This work therefore presents a novel measurement method for proteins, namely albumin, as a precursor to further work in this area. The work uses an interdigitated electrode (IDE) sensor and shows that it is capable of detecting various concentrations of albumin (from 0 to 100 g/L) with a high degree of repeatability at 200 MHz (R2 = 0.991) and 4 GHz (R2 = 0.975)

Оптимальний вибір профілю лопаті ротора вітроенергетичної установки

The paperis devoted to vertical axis wind turbine combined rotor blade profile optimalselection. It includes the description of wind turbine optimization parameters, the statement ofmulticriteria optimization problem and the description of hybrid optimization algorithmРазработан алгоритм оптимального выбора профиля лопасти комбинированного ротора с вертикальной осью вращения. В работе приведено описание параметров оптимизации ротора, поставлена задача многокритериальной оптимизации и приведен гибридный алгоритм многокритериальной оптимизацииРозроблено алгоритм оптимального вибору профілю лопаті комбінованого ротора вітроенергетичної установкиз вертикальною віссю обертання. У роботі наведено опис параметрів оптимізації ротора, поставлено задачу багатокритеріальної оптимізації та наведено гібридний алгоритм багатокритеріальної оптимізаці

Автоматизоване проектування вітроенергетичних установок з комбінованим ротором

The paper is devoted to the vertical axis wind turbine combined rotor computer-aided design. Itincludes the description of main types of vertical axis rotors and their structural parameters. It is solved theproblem of combined rotor structural and parameter synthesisРассмотрено проектирование автоматизированных ветроэнергетических установок с вертикальной осью вращения и комбинированным ротором. Описаны основные типы роторов с вертикальной осью вращения и ихструктурные параметры. Решена задача структурного и параметрического синтеза комбинированного ротораРозглянуто проектування автоматизованих вітроенергетичних установок з вертикальною віссю обертання такомбінованим ротором. Описано основні типи роторів з вертикальною віссю обертання та їх структурні параметри. Розв’язано задачу структурного та параметричного синтезу комбінованого ротор

Експериментальна перевірка теореми оборотності для осесиметричного тіла з оперенням

Wind tunnel tests were implemented for experimental verification of the reversibility theoremfor three various shapes of fore body for an axially symmetric thin body in direct and reverse streams. Besides,such tests were implemented for UAV models with three types of wings. Results of investigationsshowed that the error of execution reversibility theorem consequence can achieve 12.5% at the range ofangles of attack from 0 to 20° (accordingly, from 180° to 200°)Проведены испытания в аэродинамической трубе для экспериментальной проверки теоремы обратимости длятрех различных форм носовой части осесимметричного тела в прямом и обратном потоках. Кроме того, такиеиспытания проведены для моделей БПЛА с тремя типами крыльев. Результаты исследований показали, что ошибка выполнения следствия из теоремы обратимости может достигать 12.5% в диапазоне углов атаки от 0 до20° (соответственно, от 180° до 200°)Проведено випробування в аеродинамічній трубі для експериментальної перевірки теореми оборотності длятрьох різних форм носової частини осесиметричного тіла в прямому і зворотному потоках. Крім того, такі випробування проведено для моделей БПЛА з трьома типами крил. Результати досліджень показали, що помилка виконання слідства з теореми оборотності може досягати 12.5% у діапазоні кутів атаки від 0 до 20° (відповідно,від 180° до 200°

Interaction of hydrocortisone with ATP and adenosine on nerve-mediated contractions of frog skeletal muscle

The inhibitory effects of ATP and adenosine on the nerve-mediated contractile responses of isolated sartorius muscle of the frog, Rana ridibunda, evoked by electrical field stimulation (EFS) were studied using pharmacological organ-bath technique. The effects of hydrocortisone applied in vitro and in vivo on contractility of sartorius muscle were also examined. ATP (100 μM) significantly reduced the amplitude of contraction to EFS of sartorius muscle, while pyridoxalphosphate-6-azonphenyl-2′,4′-disulfonic acid (PPADS; 10 μM), a P2 receptor antagonist, abolished inhibitory effect of ATP. A similar inhibitory effect of adenosine (100 μM) was fully antagonized by 8-(p-sulfophenyl)-theophylline (8-SPT, 100 μM), a P1 receptor antagonist. Incubation of the tissue with hydrocortisone (10 μM) caused a slight, but significant, decrease of muscle contractions. After incubation of muscle preparations with both hydrocortisone and ATP, no inhibition of muscle contractility was registered. A single injection of hydrocortisone (100 mg/kg) 12 h prior to experiments to frogs did not significantly change the nerve-mediated contractility of isolated sartorius muscle; however, it abolished the inhibitory action of ATP without changing inhibitory activity of adenosine. After treatment of frogs with hydrocortisone for 14 days (100 mg/kg/day), both ATP and adenosine retained their inhibitory action on EFS-induced contractions of the muscle, and their effects were antagonized by PPADS and 8-SPT, respectively. It is concluded that hydrocortisone has antagonistic actions against the inhibitory effects of ATP at the frog neuromuscular junction, although this effect is lost following long-term treatment with hydrocortisone. © 2009 Elsevier B.V