Publications by authors named "Liptak A"

Background: To preserve the benefit of atrial sensing without the implantation of an additional lead, a single-lead ICD system with a floating atrial dipole (DX ICD) has been developed. The purpose of this nationwide survey was to provide an overview of the current key influences of device selection focusing on DX ICD and to test the applicability of a previously published decision-making flowchart of ICD-type selection.

Methods: An online questionnaire was sent to all implanting centers in Hungary.

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Background: Physicians in internal medicine lack comfort and skills required to diagnose and treat substance use disorder (SUD). Formal training in substance use treatment within primary care training has traditionally been inconsistent and sparse. The purpose of this study is to assess the impact of a longitudinal experiential addiction curriculum on the attitudes and experiences of graduates from a primary care/internal medicine residency program that included formal addiction didactics, rotations in an outpatient addiction clinic embedded within the resident primary care clinic, and exposure to addiction medicine faculty across treatment settings.

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Background: People with a diagnosis of mild cognitive impairment (MCI) often struggle with uncertainty and fear when learning of and coping with their diagnosis. However, little is known about their experiences and perspectives, and those of their care partners, when seeking out and undergoing a diagnostic evaluation for their cognitive symptoms.

Method: This study is a secondary analysis of a focus group discussion that was initially conducted to learn the perspectives and experiences of participants and their care partners during a mock disclosure session of brain scan results.

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Dopamine neurons in the ventral tegmental area (VTA) encode reward prediction errors and can drive reinforcement learning through their projections to striatum, but much less is known about their projections to prefrontal cortex (PFC). Here, we studied these projections and observed phasic VTA-PFC fiber photometry signals after the delivery of rewards. Next, we studied how optogenetic stimulation of these projections affects behavior using conditioned place preference and a task in which mice learn associations between cues and food rewards and then use those associations to make choices.

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The D3 dopamine receptor, a member of the G-coupled D2 family of dopamine receptors, is expressed throughout limbic circuits affected in neuropsychiatric disorders, including prefrontal cortex (PFC). These receptors are important for prefrontal executive function because pharmacological and genetic manipulations that affect prefrontal D3 receptors alter anxiety, social interaction, and reversal learning. However, the mechanisms by which D3 receptors regulate prefrontal circuits and whether D3 receptors regulate specific prefrontal subnetworks remains unknown.

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G-protein-coupled receptors (GPCRs) initiate a variety of signaling cascades, depending on effector coupling. β-arrestins, which were initially characterized by their ability to "arrest" GPCR signaling by uncoupling receptor and G protein, have recently emerged as important signaling effectors for GPCRs. β-arrestins engage signaling pathways that are distinct from those mediated by G protein.

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Objective: To describe the subjective experiences of older adults with early-stage Alzheimer's disease or related cognitive disorders (ADRDs) and their family caregivers who participated in an art museum engagement activity.

Methods: Four focus groups were conducted with 10 persons with ADRD and 10 family caregivers following the completion of a 1-time, 3-hour engagement activity. Participants also completed a brief satisfaction survey, and associations were examined using nonparametric statistics.

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Purpose: The purpose of this study was to describe humor and laughter in persons with cognitive impairment (PWCI) and caregivers who were recalling a shared experience in a focus group.

Design: Twenty participants attended an Art Engagement Activity at the Andy Warhol Art Museum, which included a guided tour and an art project. All PWCI had medically diagnosed cognitive disorders and all caregiver participants did not.

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Two pentasaccharide sulfonic acids that were related to the antithrombin-binding domain of heparin were prepared, in which two or three primary sulfate esters were replaced by sodium-sulfonatomethyl moieties. The sulfonic-acid groups were formed on a monosaccharide level and the obtained carbohydrate sulfonic-acid esters were found to be excellent donors and acceptors in the glycosylation reactions. Throughout the synthesis, the hydroxy groups to be methylated were masked in the form of acetates and the hydroxy groups to be sulfated were masked with benzyl groups.

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The first sulfonic acid mimetic of the sulfated Lewis A pentasaccharide in which the natural L-fucose unit is replaced by a D-arabinose ring was synthesized. Formation of the sulfonic acid moiety at a pentasaccharide level could be successfully achieved by means of introduction of an acetylthio moiety into the terminal D-galactose residue and subsequent oxidation. The equatorial arrangement of the acetylthio group linked to C-3 of the galactose ring could be obtained by double nucleophilic substitutions; efficient formation of the gulo-triflate derivatives required low-power microwave (MW) activation.

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d-Glucuronate and l-iduronate-containing disaccharides related to the antithrombin-binding domain of heparin were prepared. The carboxylic function of the uronic acid unit was formed on a disaccharide level in the case of the glucuronate, while on a monosaccharide level in the case of the iduronate derivatives. Synthesis of their sulfonic acid analogues was carried out analoguosly applying sulfonatomethyl-containing acceptors in the form of either salts or methyl esters.

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Dioxane-type (9'-anthracenyl)methylene acetal of methyl 2,3-di-O-methyl-alpha-D-glucopyranoside was cleaved with LiAlH(4)/AlCl(3) (3:1) or with Na(CN)BH(3)-HCl regioselectively to provide the 4- or 6-O-(9'-anthracenyl)methyl ether, respectively. Hydrogenolytic reaction of the exo and endo isomers of dioxolane-type acetals proved to be directed by the configuration of the acetalic carbon as well as by the intramolecular participation of the adjacent-free hydroxyl; ring-opening reaction of the endo isomer of the methyl 2,3-O-(9'-anthracenyl)methylene-alpha-L-rhamnopyranoside took place with complete selectivity resulting in the axial (9'-anthracenyl)methyl ether, whereas a 1:1 mixture of the axial and equatorial ethers was formed upon the same reaction of the exo isomer. Catalytic hydrogenation of the sugar acetals resulted in (9',10'-dihydro-9'-anthracenyl)methylene derivatives without affecting the acetalic center.

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Persubstituted derivatives of phenyl and ethyl 2-O-sulfonyl-1-thio-alpha-D-manno- and beta-D-glucopyranosides were synthesized and reacted either with PhSNa or with MeSNa. The phenyl-1-thio compounds afforded the dithio-1,2-cis-axial/equatorial-alpha-D-glucopyranosides or dithio-1,2-cis-equatorial/axial-beta-D-mannopyranosides by means of S(N)2 type of reactions. Starting from the ethyl-1-thio derivatives intramolecular 1,2-thio-migration took place predominantly.

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D-glucuronate and l-iduronate containing disaccharides related to the antithrombin-binding pentasaccharide of heparin, in which one of the sulfate esters is systematically replaced by a sodium sulfonatomethyl moiety, were synthesized. The sulfonic acid group was introduced by stereoselective radical addition onto the exomethylene moiety of the appropriate glycoside derivatives, and the resulting sulfonatomethyl glucosides were used as acceptors.

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Synthesis of tetra- and hexasaccharides built up from a beta-(1-->6)-linked galactopyranosyl backbone with arabinofuranosyl side chains at position 3 and with a 3-aminopropyl spacer related to arabinogalactans is described. These oligosaccharides were prepared for investigation of monoclonal antibodies raised against arabinogalactan proteins (AGPs) from pressed juice of Echinacea purpurea.

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Bacteria in a biofilm are enmeshed in a self-synthesized extracellular polysaccharide matrix (PGA), which is a linear polymer of beta(1,6)-linked N-acetylglucosamine (GlcNAc) residues. Dispersin B (DspB), a soluble glycoside hydrolase produced by the periodontal pathogen Actinobacillus actinomycetemcomitans degrades PGA. The enzyme DspB is an alpha/beta TIM-barrel protein and belongs to family 20 glycosyl hydrolases members.

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A combined but independently applied NMR and QM procedure has been used to investigate the conformational properties of the exchangeable hydroxyl protons of polyalcohols. In this study, to demonstrate the applicability of such a strategy, we investigated a simple monosaccharide, i.e.

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Anomeric pairs of ketopyranosyl glycosides with various substituents at C(alpha), C(beta) and C(gamma) were synthesized from the corresponding thioglycosides, and the influence of the C(alpha)-C(beta)-C(gamma)-H(gamma) torsion angle and substituent effects on the three-bond carbon-proton couplings was studied. The cis coupling constants range from 1 to 2Hz. The trans couplings are generally as small as 2.

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To elucidate how temperature effects subsite mapping of a thermostable alpha-amylase from Bacillus licheniformis (BLA), a comparative study was performed by using 2-chloro-4-nitrophenyl (CNP) beta-maltooligosides with degree of polymerisation (DP) 4-10 as model substrates. Action patterns, cleavage frequencies and subsite binding energies were determined at 50 degrees C, 80 degrees C and 100 degrees C. Subsite map at 80 degrees C indicates more favourable bindings compared to the hydrolysis at 50 degrees C.

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The chemical synthesis of the glycopeptidolipid-type pentasaccharide hapten of Mycobacterium avium serovar 19 with a trifluoroacetamido spacer at the reducing end is described. The spacer-armed pentasaccharide 31, when conjugated to an immunogenic protein, can be applied to the serodiagnosis of mycobacterial infections. The questionable structure of the penultimate monosaccharide unit was clarified as 6-deoxy-3-C-methyl-2,4-di-O-methyl-L-mannopyranose.

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