Search

Abstract: Several lines of evidence suggest that imidazoline receptors mediate various physiological processes. It is rather difficult, however, to distinguish the imidazoline receptor-mediated effects from the alpha2-adrenoceptor-mediated ones due to the reasonable affinity of most imidazoline ligands for the alpha2-adrenoceptors. In the present study the effects of different imidazoline ligands were tested on the electrical field stimulation (EFS)-induced gastric contractions in wild-type (WT), alpha2A-, alpha2B- and alpha2C-adrenoceptor knockout (KO) mice in order to analyze, whether imidazoline I 1 and I 2 receptors take part in the regulation of gastric motor activity. Clonidine, moxonidine and rilmenidine inhibited the EFS-induced gastric contractions in a concentration dependent manner in WT, alpha2B- and alpha2C-adrenoceptor KO mice, whereas they had no or only weak effect in alpha2A-adrenoceptor KO mice. Their effects in WT mice were inhibited by idazoxan and BRL 44408, but not by ARC 239, AGN 192403 and BU 224. The endogenous imidazoline receptor ligand agmatine failed to affect the EFS-induced contractions, while harmane (an other endogenous imidazoline receptor ligand) and 2-BFI (a selective imidazoline I 2 receptor agonist) exerted a slight effect in both WT and alpha2A-adrenoceptor KO mice, but this was not reversible by idazoxan, AGN 192403 and BU 224. It can be concluded, that the inhibitory effect of the tested imidazoline compounds on cholinergic gastric contractions is mediated mainly by alpha2A-adrenoceptors. Although at higher concentrations other receptors may also contribute to their effects, the lack of inhibition by AGN 192403 and BU 224 suggests that these are not imidazoline I 1 and I 2 receptors. [Copyright &y& Elsevier]

The reactions of 5-chloro-6-phenyl-,4,5-dichloro-6-phenyl- and 5-chloro-6-(2,4-dichlorophenyl)-2-methylpyridazin-3(2H)-ones with 57% aqueous hydrogen iodide or sodium iodide in dimethyl formamide, respectively, are described. Upon treatment of chloro compounds with 57% hydrogen iodide, besides nucleophilic substitution of chloro- by iodo substituent, subsequent hydrodeiodination also occurred. Thus, e.g. 4,5-dichloro-2-methyl-6-phenylpyridazin-3(2H)-one gave first 5-chloro-4-iodo-2-methyl-6-phenylpyridazin-3(2H)-one and in the next step, 5-chloro-2-methyl-6-phenylpyridazin-3(2H)-one. Similarly, treatment of 5-chloro-2-methyl-6-phenylpyridazin-3(2H)-one led to the formation of 5-iodo-2-methyl-6-phenylpyridazin-3(2H)-one and 2-methyl-6-phenylpyridazin-3(2H)-one. The structure of each new product was proved by ¹H, 13C and partly by 15N NMR spectroscopy. [ABSTRACT FROM AUTHOR]

Abstract: α2-Adrenoceptors are involved in various physiological functions, particularly in the cardiovascular system and the central nervous system. Different adrenoceptor subtypes (α2A, α2B and α2C) have been recognised and the different subtypes may have role in activation of distinct physiological and pharmacological pathways. Some of the actions of α2-adrenoceptor stimulants are likely to be mediated exclusively by α2A-adrenoceptor subtype, like antihypertensive and bradycardic effects. α2A-Adrenoceptor may have dominant role in sedative and hypothermic actions, in inhibition of gastric acid secretion and gastric motor activity, as well as in stabilisation of thrombus. Besides α2A-adrenergic receptors α2B and α2C-adrenoceptor subtypes may also be involved in some of the classical effects of α2-adrenoceptor stimulants, like in presynaptic regulation of transmitter release and antinociceptive action. α2B-Adrenoceptor has dominant role in the vasoconstrictor effect of α2-adrenoceptor agonists, and its activation induces contraction of rat uterus in late pregnancy. α2B-Adrenoceptor mediates gastric mucosal protective action initiated centrally in the rat, as well as it may have role also in developmental or reproductive processes. α2C-Adrenoceptor subtypes may be involved in stress-dependent depression and other psychiatric illnesses like attention deficit hyperactivity disorder—together with α2A-adrenoceptor. α2C-Adrenergic receptors seem to mediate peripheral actions as well, like venous vasoconstriction. Identification of separate physiological roles for different α2-adrenergic receptor subtypes could improve design of novel compounds for specific therapeutic goals. [Copyright &y& Elsevier]

Abstract: The therapeutic usefulness of current agents that activate the three α2-adrenoceptors, α2A, α2B and α2C is limited by their lack of subtype selectivity. One approach to the development of subtype-selective agents is the in silico docking of potential ligands to the receptors in quantitative molecular modeling studies. Because the crystal structure of the α2-adrenoceptors is not known, we used homology modeling based on the published structure of bovine rhodopsin. We developed individual models for each of the three receptors, which were found to accurately represent published data from both radioligand binding mutagenesis experiments. Using 18 non-subtype-selective agents to validate the models, the calculated transformed and the experimental binding free energies were satisfactory correlated (r 2 A =0.888, r 2 B =0.887, r 2 C =0.790). The binding pockets differed in size (482–619Å3) with the α2B receptor subtype having the largest and the α2c the smallest cavity. The binding sites for all three subtypes were found to be essentially identical with the exception of two subtype-specific residues, and thus we were unable to identify any significant differences in the interactions of ligands with the three receptor subtypes. Although, the binding properties of all three receptors are very similar, the differences in pocket volume and two subtype-specific residues in the binding pocket might play an as yet undocumented role in subtype selectivity. [Copyright &y& Elsevier]

Abstract: We sought an isolated vascular preparation and experimental setting where the function of α2B-adrenoceptors could be demonstrated by non-recombinant technique. ST-91 (2-[2,6-diethylphenylamino]-2-imidazoline), an α2B-adrenoceptor agonist with a mixed α adrenergic receptor type/subtype selection profile antagonized the relaxant effect of isoproterenol in endothelium-denuded rat mesenteric artery rings precontracted with phenylephrine. At 10−7 M of ST-91, the antagonism was characterized by a rightward shift of isoproterenol dose–response curve (A 50 =6.81±1.40 e−7 (n =4) vs the control 1.29±0.25 e−7 M (n =4)) with no E max depression. At 10−6 M the E max depression was prevalent (36.1±7.0% (n =4) vs the control 79.9±5.1% (n =4)); both actions could be antagonized by the α2-adrenoceptor antagonist yohimbine. The not subtype-selective α2-adrenoceptor agonist xylazine (10−7 M) did not affect the relaxant action of isoproterenol. Present findings are discussed in the light of previously reported hemodynamic effects attributed to α2B-adrenoceptors in receptor subtype-knockout animals. [Copyright &y& Elsevier]

1,5-hydride transfer-triggered cyclization reactions offering a robust method for C(sp 3 )-C(sp 3 ) coupling and the synthesis of e.g. tetrahydroquinolines have been thoroughly investigated in the literature. Catalysts allowing milder reaction conditions or the development of enantioselective processes were important recent contributions to the field, as well as the studies on subtrates with oxygen or sulfur heteroatoms (besides the originally described nitrogen heterocycles). In a series of studies, we focused on expanded, higher order H-transfers/cyclizations by positioning the interacting substituents on distanced rings. Cyclizations of appropriately functionalized biaryl and fused bicyclic systems led to 7-9 membered rings. In the frame of this research, we set out to study the feasibility of the cyclization and the factors affecting it by in silico methods. The conclusions drawn from computational studies were complemented by cyclization screens on 2-(2-vinyl)phenoxy- tert -anilines and their CH 2 -expanded analogues, the results of which are presented here. Besides isolating the expected oxazonine products in several cases, we also observed a unique dimer formation, leading to an interesting 5-6-5 ring system., Competing Interests: There are no conflicts of interest to declare., (This journal is © The Royal Society of Chemistry.)

The one disease - one target - one drug paradigm was an almost dominant principle in drug discovery from the 1960s to the 2000s. The stagnation and even decline in the productivity of drug innovation around the turn of the millennium and beyond, the realization of limitations of the one-target approach, especially in the treatment of multifactorial diseases, have drawn attention considerably to the one disease - multiple target - one drug multi-targeting drug concept. In this review, we outline old and new molecular design strategies and their practical implementation with own and other examples that also demonstrate unique therapeutic and diagnostic values and benefits of the multi-targeting approach. Finally, we point out that the full potential of the multi-targeting concept can emerge through data analytics and association methods (such as artificial intelligence) and system-based approach, preferably by linking it to quantitative systems pharmacology. This new systems pharmacology drug approach may also lead to novel breakthrough drugs, drug combinations and drug repositioning. Orv Hetil. 2020; 161(14): 523-531.

Domino cyclization reactions of N -aryl-1,4- and 1,5-benzoxazepine derivatives involving [1,5]-hydride shift or C(sp 2 )-H functionalization were investigated. Neuroprotective and acetylcholinesterase activities of the products were studied. Domino Knoevenagel-[1,5]-hydride shift-cyclization reaction of N -aryl-1,4-benzoxazepine derivatives with 1,3-dicarbonyl reagents having active methylene group afforded the 1,2,8,9-tetrahydro-7b H -quinolino [1,2- d ][1,4]benzoxazepine scaffold with different substitution pattern. The C(sp 3 )-H activation step of the tertiary amine moiety occurred with complete regioselectivity and the 6- endo cyclization took place in a complete diastereoselective manner. In two cases, the enantiomers of the chiral condensed new 1,4-benzoxazepine systems were separated by chiral HPLC, HPLC-ECD spectra were recorded, and absolute configurations were determined by time-dependent density functional theory- electronic circular dichroism (TDDFT-ECD) calculations. In contrast, the analogue reaction of the regioisomeric N -aryl-1,5-benzoxazepine derivative did not follow the above mechanism but instead the Knoevenagel intermediate reacted in an S E Ar reaction [C(sp 2 )-H functionalization] resulting in a condensed acridane derivative. The AChE inhibitory assays of the new derivatives revealed that the acridane derivative had a 6.98 μM IC 50 value.

Cloxyquin has been reported as a specific activator of TRESK [TWIK-related spinal cord K + channel (also known as K 2P 18.1)] background potassium channel. In this study, we have synthetized chemically modified analogs of cloxyquin and tested their effects on TRESK and other K 2P channels. The currents of murine K 2P channels, expressed heterologously in Xenopus oocytes, were measured by two-electrode voltage clamp, whereas the native background K + conductance of mouse dorsal root ganglion (DRG) neurons was examined by the whole-cell patch-clamp method. Some of the analogs retained the activator character of the parent compound, but, more interestingly, other derivatives inhibited mouse TRESK current. The inhibitor analogs (A2764 and A2793) exerted state-dependent effects. The degree of inhibition by 100 µ M A2764 (77.8% ± 3.5%, n = 6) was larger in the activated state of TRESK (i.e., after calcineurin-dependent stimulation) than in the resting state of the channel (42.8% ± 11.5% inhibition, n = 7). The selectivity of the inhibitor compounds was tested on several K 2P channels. A2793 inhibited TWIK-related acid-sensitive K + channel (TASK)-1 (100 µ M, 53.4% ± 13, 5%, n = 5), while A2764 was more selective for TRESK, it only moderately influenced TREK-1 and TWIK-related alkaline pH-activated K + channel. The effect of A2764 was also examined on the background K + currents of DRG neurons. A subpopulation of DRG neurons, prepared from wild-type animals, expressed background K + currents sensitive to A2764, whereas the inhibitor did not affect the currents in the DRG neurons of TRESK-deficient mice. Accordingly, A2764 may prove to be useful for the identification of TRESK current in native cells, and for the investigation of the role of the channel in nociception and migraine. SIGNIFICANCE STATEMENT: TRESK background potassium channel is a potential pharmacological target in migraine and neuropathic pain. In this study, we have identified a selective inhibitor of TRESK, A2764. This compound can inhibit TRESK in native cells, leading to cell depolarization and increased excitability. This new inhibitor may be of use to probe the role of TRESK channel in migraine and nociception., (Copyright © 2019 by The American Society for Pharmacology and Experimental Therapeutics.)

Introduction: Data during routine patient care are created in multiple digital and paper-based hardcopy systems, therefore their retrieval is cumbersome in the follow-up of patients. Multiple sclerosis is the most prevalent neurological disorder in the young age, with major consequences on health and socio-economic status., Aim: We set forth to create a user-friendly, detailed local database where it is easy to access, register and analyze data. Based on our experiences during building this registry, we develop the model of a modern type of database., Method: First we established a local registry in Excel, then data were transferred to the worldwide used iMed system. Separate pages were used to register basic data, follow-up visits, relapses, accompanying diseases, results of neuroimaging, cerebrospinal fluid, evoked response and other tests, pharmacological and non-pharmacological treatments., Results: The database currently contains data of 316 patients. MRI was performed in 96%, cerebrospinal fluid examination in 45% of the patients. The rate of primary progressive disease at disease onset is 9%. Disease modifying treatments were applied in 82% of the patients., Conclusion: The traditional manual data entry and data export in PDF format is obsolete and time-consuming. The development of local disease-specific databases appropriate for clinical and research purposes requires continuous and mostly automatic data entry. In future local registries the establishment of uniform documentational language and structure, and automatic transfer of information among different digital systems are required. We present the model of such a registry, which is based on a healthcare data lake. Orv Hetil. 2019; 160(4): 131-137.

Vast amounts of data are created during routine patient care which are stored in unstructured digital and hardcopy formats in healthcare institutions. Analysis of large databases help to define the healthcare needs of the population and to organize healthcare services for specific diseases. As a model, we selected multiple sclerosis (MS), a disease with well-defined diagnostic criteria, a usually inpatient initial diagnosis, and a need for regular outpatient check-up. Using multiple sclerosis as an example, we set forth to screen and analyze international and Hungarian databases. In the framework of the initiation of the data lake system of Semmelweis University, we aim to define features of the data system needed for disease-specific databases for future applications. To determine essential data-entry criteria for such a database, we review the most important multiple sclerosis registries. We evaluate the type of registered data, structure of database, privacy issues, the availability and ways of application of the databases. Initially, the MS databases were created locally, aiming for better care of patients. As a further step, data were collected for scientific research by national and international co-operations. Disease-specific databases have become of high priority for national healthcare providers, and long-term information on a population ("real-world" data) is extremely important to assess the effectivity and safety of a treatment at the population level. Our analysis contributes to a project which focuses on the aspects of developing a data lake at a service provider level including clinical, diagnostic and digital healthcare departments of Semmelweis University, Budapest, Hungary. Orv Hetil. 2019; 160(4): 123-130.

The rapidly accumulating, heterogeneous, numerous biomedical data and the increasing knowledge represent both the key areas and the major bottleneck in the complete realization of personalized medicine. Traditional clinical aims as well as decision-making processes in drug research need systems-based integration of data and their analyses, which require a wide range of new mathematical approaches and application of information technologies. In the world of biomarkers, all such tasks correspond to three types of biomarkers, namely, endpoint, target and diagnostic biomarkers, which together form a complex network. To decipher the networks, probabilistic graphical models are introduced. Briefly, the authors illustrate their use for exploration and visualization of direct dependencies among biomarkers. Finally, construction of decision networks and their application to structural and quantitative optimization of biomarkers are discussed to provide a novel type of supporting tools for clinical practice.

Despite famous serendipitous drug repositioning success stories, systematic projects have not yet delivered the expected results. However, repositioning technologies are gaining ground in different phases of routine drug development, together with new adaptive strategies. We demonstrate the power of the compound information pool, the ever-growing heterogeneous information repertoire of approved drugs and candidates as an invaluable catalyzer in this transition. Systematic, computational utilization of this information pool for candidates in early phases is an open research problem; we propose a novel application of the enrichment analysis statistical framework for fusion of this information pool, specifically for the prediction of indications. Pharmaceutical consequences are formulated for a systematic and continuous knowledge recycling strategy, utilizing this information pool throughout the drug-discovery pipeline.

The aim of this study is to determine the efficacy of a potent and specific vascular adhesive protein-1/semicarbazide-sensitive amine oxidase (VAP-1/SSAO) inhibitor, LJP 1207, as a potential antiangiogenic and anti-inflammatory agent in the therapy of corneal neovascularization. Corneal neovascularization was induced with intrastromal suturing in rabbits (n = 20). Topical treatment with VAP-1/SSAO inhibitor LJP 1207 (n = 5, 4 times a day), bevacizumab (n = 5, daily), their combination (n = 5) and vehicle only (n = 5, 4 times a day) were applied postoperatively for 2 weeks. The development and extent of corneal neovascularization were evaluated by digital image analysis. At the end of the observation period, the level of corneal and serum VAP-1/SSAO activity was measured fluorometrically and radiochemically. The corneal VAP-1/SSAO activity was significantly elevated in the suture-challenged vehicle-treated group (3,075 ± 1,009 pmol/mg/h) as compared to unoperated controls (464.2 ± 135 pmol/mg/h, p < 0.001). Treatment with LJP 1207 resulted in slower early phase neovascularization compared to vehicle-treated animals (not significant). At days 7-14, there was no significant difference in the extent of corneal neovascularization between inhibitor- and vehicle-treated corneas, even though inhibitor treatment caused a normalization of corneal VAP-1/SSAO activity (885 ± 452 pmol/mg/h). Our results demonstrate that the significant elevation of VAP-1/SSAO activity due to corneal injury can be prevented with VAP-1/SSAO inhibitor LJP 1207 treatment. However, normalization of VAP-1/SSAO activity in this model does not prevent the development of corneal neovascularization.

SSAO/VAP-1 participates in the accumulation of leukocytes at the site of inflammation. A new SSAO inhibitor, SzV-1287 was demonstrated to inhibit both acute and chronic inflammation in rats more effectively than the known enzyme inhibitor, LJP-1207. Surprisingly, the SSAO activity was not increased, but decreased both in acute and chronic inflammation. Though experiments are in progress to clarify these findings, the enzyme might play a role in the very early phase of inflammation and be inactivated during leukocyte extravasation.

Aim: The effects of vitamin D3 have been investigated on various tumors, including colorectal cancer (CRC). 25-hydroxyvitamin-D3-24-hydroxylase (CYP24A1), the enzyme that inactivates the active vitamin D3 metabolite 1,25-dihydroxyvitamin D3 (1,25-D3), is considered to be the main enzyme determining the biological half-life of 1,25-D3. During colorectal carcinogenesis, the expression and concentration of CYP24A1 increases significantly, suggesting that this phenomenon could be responsible for the proposed efficacy of 1,25-D3 in the treatment of CRC. The aim of this study was to investigate the anti-tumor effects of vitamin D3 on the human CRC cell line Caco-2 after inhibition of the cytochrome P450 component of CYP24A1 activity., Methods: We examined the expression of CYP24A1 mRNA and the effects of 1,25-D3 on the cell line Caco-2 after inhibition of CYP24A1. Cell viability and proliferation were determined by means of sulforhodamine-B staining and bromodeoxyuridine incorporation, respectively, while cytotoxicity was estimated via the lactate dehydrogenase content of the cell culture supernatant. CYP24A1 expression was measured by real-time reverse transcription polymerase chain reaction. A number of tetralone compounds were synthesized to investigate their CP24A1 inhibitory activity., Results: In response to 1,25-D3, CYP24A1 mRNA expression was enhanced significantly, in a time- and dose-dependent manner. Caco-2 cell viability and proliferation were not influenced by the administration of 1,25-D3 alone, but were markedly reduced by co-administration of 1,25-D3 and KD-35, a CYP24A1-inhibiting tetralone. Our data suggest that the mechanism of action of co-administered KD-35 and 1,25-D3 does not involve a direct cytotoxic effect, but rather the inhibition of cell proliferation., Conclusion: These findings demonstrate that the selective inhibition of CYP24A1 by compounds such as KD-35 may be a new approach for enhancement of the anti-tumor effect of 1,25-D3 on CRC.

Several lines of evidence suggest that imidazoline receptors mediate various physiological processes. It is rather difficult, however, to distinguish the imidazoline receptor-mediated effects from the alpha₂-adrenoceptor-mediated ones due to the reasonable affinity of most imidazoline ligands for the alpha₂-adrenoceptors. In the present study the effects of different imidazoline ligands were tested on the electrical field stimulation (EFS)-induced gastric contractions in wild-type (WT), alpha₂A-, alpha₂B- and alpha₂C-adrenoceptor knockout (KO) mice in order to analyze, whether imidazoline I₁ and I₂ receptors take part in the regulation of gastric motor activity. Clonidine, moxonidine and rilmenidine inhibited the EFS-induced gastric contractions in a concentration dependent manner in WT, alpha₂B- and alpha₂C-adrenoceptor KO mice, whereas they had no or only weak effect in alpha₂A-adrenoceptor KO mice. Their effects in WT mice were inhibited by idazoxan and BRL 44408, but not by ARC 239, AGN 192403 and BU 224. The endogenous imidazoline receptor ligand agmatine failed to affect the EFS-induced contractions, while harmane (an other endogenous imidazoline receptor ligand) and 2-BFI (a selective imidazoline I2 receptor agonist) exerted a slight effect in both WT and alpha2A-adrenoceptor KO mice, but this was not reversible by idazoxan, AGN 192403 and BU 224. It can be concluded, that the inhibitory effect of the tested imidazoline compounds on cholinergic gastric contractions is mediated mainly by alpha₂A-adrenoceptors. Although at higher concentrations other receptors may also contribute to their effects, the lack of inhibition by AGN 192403 and BU 224 suggests that these are not imidazoline I₁ and I₂ receptors., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Enantiomers of 2,3-dihydro-1,4-benzodioxine derivatives possessing both thrombin and fibrinogen GPIIb/IIIa binding inhibitory activities were prepared from (R)- and (S)-glycidol as potential dual antithrombotic compounds. The influence of chirality and substitution pattern on thrombin inhibition and on inhibition of fibrinogen binding to GPIIb/IIIa was analyzed. Docking studies were used in an attempt to rationalize the results. The (S)-isomers of both 2,3-dihydro-1,4-benzodioxine regioisomers at positions 6 and 7 were found to be better thrombin inhibitors than the corresponding (R)-enantiomers, whereas we observed that stereochemistry does not display a consistent influence on fibrinogen GPIIb/IIIa binding inhibitory activity. Compound 11b, the (S)-isomer of the 6-substituted regioisomer, possessed the best balanced dual activity, with Ki(thrombin) = 1.67 ± 0.27 μM and IC50(GPIIb/IIIa) = 0.665 ± 0.26 μM, raising the hope that merging anticoagulant and platelet antiaggregatory activities in the same molecule could lead to successful multitarget antithrombotic agents., (Copyright © 2013 Elsevier Masson SAS. All rights reserved.)

Esters of 1,4-benzoxazine and 1,4-benzodioxine compounds 1 and 10, which combine thrombin inhibitory and GPIIb/IIIa antagonistic activity in one molecule are shown to inhibit endothelial cell migration and tube formation in vitro and angiogenesis in the chicken chorioallantoic membrane (CAM) assay. The corresponding carboxylic acids 1 (R(2) = H) and 11 were devoid of anti-angiogenic activity, most probably due to their insufficient entry into the cell. Although thrombin inhibition remains the most probable explanation for their inhibition of angiogenesis, VEGFR2 kinase assay suggest that other targets such as VEGFR2 might be involved., (Copyright © 2012 Elsevier Masson SAS. All rights reserved.)

Vascular adhesion protein-1 (VAP-1) controls the adhesion of lymphocytes to endothelial cells and is upregulated at sites of inflammation. Moreover, it expresses amine oxidase activity, due to the sequence identity with semicarbazide-sensitive amine oxidase. Recent studies indicate a significant role for VAP-1 in neovascularization, besides its contribution to inflammation. Pathological blood vessel development in severe ocular diseases (such as diabetes, age-related macula degeneration, trauma and infections) might lead to decreased visual acuity and finally to blindness, yet there is no clear consensus as to its appropriate treatment. In the present case study, the effects of two VAP-1 inhibitors on experimentally induced corneal neovascularization in rabbits were compared with the effects of a known inhibitor of angiogenesis, bevacizumab, an anti-vascular endothelial growth factor antibody. In accordance with recent literature data, the results of the preliminary study reported here indicate that the administration of VAP-1 inhibitors is a potentially valuable therapeutic option in the treatment of corneal neovascularization.

Background: Benzylamine exerts insulin-like effects in adipocytes (e.g., glucose uptake and antilipolysis) and improves glucose handling in rodents., Results: In murine adipocytes, benzylamine mimics another insulin action: it enhances apelin expression in a manner that is blocked by the semicarbazide-sensitive amine oxidase/vascular adhesion protein-1 (SSAO/VAP-1) inhibitor semicarbazide. It is shown that in human adipocytes, benzylamine activates glucose transport, but its effects are not additive to maximal insulin stimulation. Benzylamine effects are hydrogen peroxide dependent. They can be reproduced by novel substrates, but not by benzaldehyde., Conclusion: Owing to the parallelism between the in vitro insulin mimicry and the in vivo improvement of glucose handling elicited by benzylamine in rodents, the SSAO/VAP-1 substrates, with stronger effects on human adipocytes than benzylamine, show promising applications for the treatment of insulin resistance.

The therapeutic usefulness of current agents that activate the three alpha(2)-adrenoceptors, alpha(2A), alpha(2B) and alpha(2C) is limited by their lack of subtype selectivity. One approach to the development of subtype-selective agents is the in silico docking of potential ligands to the receptors in quantitative molecular modeling studies. Because the crystal structure of the alpha(2)-adrenoceptors is not known, we used homology modeling based on the published structure of bovine rhodopsin. We developed individual models for each of the three receptors, which were found to accurately represent published data from both radioligand binding mutagenesis experiments. Using 18 non-subtype-selective agents to validate the models, the calculated transformed and the experimental binding free energies were satisfactory correlated (r(2)(A)=0.888, r(2)(B)=0.887, r(2)(C)=0.790). The binding pockets differed in size (482-619A(3)) with the alpha(2B) receptor subtype having the largest and the alpha(2c) the smallest cavity. The binding sites for all three subtypes were found to be essentially identical with the exception of two subtype-specific residues, and thus we were unable to identify any significant differences in the interactions of ligands with the three receptor subtypes. Although, the binding properties of all three receptors are very similar, the differences in pocket volume and two subtype-specific residues in the binding pocket might play an as yet undocumented role in subtype selectivity.

Based on the indoloquinoline alkaloids cryptolepine (1), neocryptolepine (2), isocryptolepine (3) and isoneocryptolepine (4), used as lead compounds for new antimalarial agents, a series of tricyclic and bicyclic analogues, including carbolines, azaindoles, pyrroloquinolines and pyrroloisoquinolines was synthesized and biologically evaluated. None of the bicyclic compounds was significantly active against the chloroquine-resistant strain Plasmodium falciparum K1, in contrast to the tricyclic derivatives. The tricyclic compound 2-methyl-2H-pyrido[3,4-b]indole (9), or 2-methyl-beta-carboline, showed the best in vitro activity, with an IC(50) value of 0.45 microM against P. falciparum K1, without apparent cytotoxicity against L6 cells (SI>1000). However, this compound was not active in the Plasmodium berghei mouse model. Structure-activity relationships are discussed and compared with related naturally occurring compounds.

Isoflavones are suitable guest molecules for inclusion complex formation with cyclodextrins (CDs). The molecular encapsulation with CDs results in a solid, molecularly dispersed form and in a significantly improved aqueous solubility of isoflavones. Genistein, a key isoflavone constituent of Ononidis spinosae radix was found to form a supramolecular, non-covalent inclusion complex with both beta-cyclodextrin (beta-CD) and gamma-cyclodextrin (gamma-CD), while it did not form a stable complex with alpha-CD. The guest genistein was found to spatially located in the less polar cavity of cyclodextrin. The isolated binary genistein/CD complexes appeared novel crystalline lattices. The in vitro dissolution of genistein entrapped into both beta- and gamma-CD, significantly surpassed that of the plain isoflavone.

The present study confirmed our previous assumption on the crucial role of central alpha2B-like adrenoceptor subtype in gastric mucosal defense. It was found that beside clonidine, rilmenidine, an alpha2/imidazoline receptor agonist and ST-91, an alpha2B-adrenoceptor preferring agonist inhibited the mucosal lesions induced by ethanol given intracerebroventricularly (i.c.v.). The ED50 values for clonidine, rilmenidine and ST-91 are 0.2, 0.01 and 16 nmol/rat i.c.v., respectively. The effect was reversed by the intracerebroventricularly injected alpha2B/2C-adrenoceptor antagonists prazosin and ARC-239, indicating the potential involvement of central alpha2B/2C-adrenoceptor subtype in the protective action. The gastroprotective effect of adrenoceptor stimulants was reversed by bilateral cervical vagotomy, suggesting that vagal nerve is likely to convey the central action to the periphery. In gastric mucosa both nitric oxide and prostaglandins may mediate the centrally-induced effect, since both indomethacin and N(G)-nitro-L-arginine reversed the protective effect of alpha2-adrenergic stimulants. Though expression of mRNA of alpha2B-, as well as alpha2A- and alpha2C-adrenoceptor subtypes was demonstrated in gastric mucosa of the rat, the hydrophilic ST-91, given peripherally (orally, subcutaneously), failed to exert mucosal protection, in contrast with clonidine and rilmenidine which were also effective. Consequently, while peripheral alpha2B-adrenoceptors are not likely to be involved in gastric mucosal protection, activation of central alpha2B-like adrenoceptor subtype may initiate a chain of events, which result in a vagal dependent gastroprotective action.

Three-dimensional structure-activity relationship studies of alpha2a-adrenoceptor agonists were carried out by Distance Comparison (DISCOthech) and Comparative Molecular Field Analysis (CoMFA) methods to define the pharmacophore and a quantitative model, respectively, of this class of compounds. The statistical validation of the CoMFA model indicates its high predictive performance for binding affinities of new alpha2a-adrenoceptor agonists.

Background and Purpose: 2,3,5-Triphenyltetrazolium chloride (TTC) staining measures tissue viability used to evaluate infarct size. The goal of this study was to compare viability of neuronal tissue during the early phases of ischemia-reperfusion assessed either by perfusion of the brain with TTC solution transcardially, in vivo, or by staining brain slices, in vitro., Methods: The middle cerebral artery was occluded for 1 h in male SPRD rats and then reperfused for 0, 1, 4, 8, 16 and 24 h. Ischemic damage was evaluated by TTC staining, in vivo and in vitro, and by histology (Luxol Fast Blue and Fluoro-Jade staining, electron microscopy)., Results: Core volume of tissue injury measured in vivo was large at 0 h and steadily decreased by 50% (p<0.001) up to 16 h, but substantially increased from 16 to 24 h of reperfusion. In contrast, a significant core volume appeared at 4 h only, in vitro, and gradually increased up to 24 h. Core volume was larger in vivo than in vitro at all times except at 16 h when the opposite was observed. Evans blue administered intracardially stained TTC-negative areas at 1 and 24 h. Histology covered the evolution of serious tissue injury but also demonstrated some morphologically preserved neurons in the infracted area at 24 h., Conclusions: Formation of formazan from TTC can depend on both the staining method and the metabolic burden of the brain tissue causing uncertainties in the volume of ischemia-induced brain injury measured by TTC staining.

One possible mechanism of action of the available K-channel blocking agents used to treat arrhythmias is to selectively inhibit the HERG plus MIRP channels, which carry the rapid delayed rectifier outward potassium current (I(Kr)). These antiarrhythmics, like sotalol, dofetilide and ibutilide, have been classified as Class III antiarrhythmics. However, in addition to their beneficial effect, they substantially lengthen ventricular repolarization in a reverse-rate dependent manner. This latter effect, in certain situations, can result in life-threatening polymorphic ventricular tachycardia (torsades de pointes). Selective blockers (chromanol 293B, HMR-1556, L-735,821) of the KvLQT1 plus minK channel, which carriy the slow delayed rectifier potassium current (I(Ks)), were also considered to treat arrhythmias, including atrial fibrillation (AF). However, I(Ks) activates slowly and at a more positive voltage than the plateau of the action potential, therefore it remains uncertain how inhibition of this current would result in a therapeutically meaningful repolarization lengthening. The transient outward potassium current (I(to)), which flows through the Kv 4.3 and Kv 4.2 channels, is relatively large in the atrial cells, which suggests that inhibition of this current may cause substantial prolongation of repolarization predominantly in the atria. Although it was reported that some antiarrhythmic drugs (quinidine, disopyramide, flecainide, propafenone, tedisamil) inhibit I(to), no specific blockers for I(to) are currently available. Similarly, no specific inhibitors for the Kir 2.1, 2.2, 2.3 channels, which carry the inward rectifier potassium current (I(kl)), have been developed making difficult to judge the possible beneficial effects of such drugs in both ventricular arrhythmias and AF. Recently, a specific potassium channel (Kv 1.5 channel) has been described in human atrium, which carries the ultrarapid, delayed rectifier potassium current (I(Kur)). The presence of this current has not been observed in the ventricular muscle, which raises the possibility that by specific inhibition of this channel, atrial repolarization can be lengthened without similar effect in the ventricle. Therefore, AF could be terminated and torsades de pointes arrhythmia avoided. Several compounds were reported to inhibit I(Kur)(flecainide, tedisamil, perhexiline, quinidine, ambasilide, AVE 0118), but none of them can be considered as specific for Kv 1.5 channels. Similarly to Kv 1.5 channels, acetylcholine activated potassium channels carry repolarizing current (I(KAch)) in the atria and not in the ventricle during normal vagal tone and after parasympathetic activation. Specific blockers of I(KAch) can, therefore, also be a possible candidate to treat AF without imposing proarrhythmic risk on the ventricle. At present several compounds (amiodarone, dronedarone, aprindine, pirmenol, SD 3212) were shown to inhibit I(KAch) but none of them proved to be selective. Further research is needed to develop specific K-channel blockers, such as I(Kur)and I(KAch) inhibitors, and to establish their possible therapeutic value.

Cardiac arrhythmias represent a major area of cardiovascular research, and for drug therapy, a large choice of antiarrhythmic agents have been available. However, clinical trials with antiarrhythmic drugs have recently indicated that serious side effects may considerably limit the use of various antiarrhythmic agents, in particular, for preventing arrhythmia-related mortality. Amiodarone with its complex mode of action, while exerting a strong and favorable antiarrhythmic action, posseses extracardiac untoward side effects originating from its chemical structure. In this paper, we report on our attempt to develop conceptually new, therapeutically valuable antiarrhythmic compounds, in which Class I/B and Class III features were combined into single molecules bearing no structural resemblance to amiodarone. Synthesis and pharmacological screening of series of N-(phenylalkyl)-N-(phenoxyalkyl)amines led us to discover some new promising compounds with the required dual mode of action. GYKI-16638, selected for further investigation, was also found to possess a remarkable in vivo antiarrhythmic effect, and it is now considered as a safe new antiarrhythmic drug candidate.

The synthesis, in vitro/in vivo antifungal evaluation and a structure-activity relationship (SAR) study of 3(2H)-pyridazinones was carried out. The results reported here may be helpful in the structural identification and understanding of the minimum structural requirements for these molecules acting as antifungal agents. In addition, the most active structure in this series was tested for its capacity of inhibiting Saccharomyces cerevisiae beta 1,3-glucan synthase and chitin synthase, enzymes that catalyze the synthesis of the major polymers of the fungal cell wall.