bluuebunny/crossref_metadata_2025_split huggingface dataset:
Substrates dissociate dopamine transporter oligomers
Authors: Chen Nianhang , Reith Maarten E. A. 
Published: March 2008

AbstractSubstrate‐induced endocytic trafficking of dopamine transporter (DAT) has been observed, but little is known about the regulation of DAT oligomerization by substrate. The present study investigates the effect on substrates on DAT oligomerization and explores a potential link with the presence of DAT at the cell surface in human embryonic kidney cells transiently or stably expressing N‐terminal tagged DAT constructs. Dopamine (100 μM) or amphetamine (2–10 μM) reduced Myc‐DAT coimmunoprecipitated along with Flag‐DAT (oligomeric DAT) in tandem with a reduction in surface DAT determined by biotinylation. Dopamine (10–1000 μM) and amphetamine (0.2–200 μM) reduced DAT oligomerization as assessed by cross‐linking with copper sulfate phenanthroline or Cu2+. Inhibition of endocytosis by 10 μM phenylarsine oxide or 450 mM sucrose counteracted the effect of 10 μM DA or 2 μM amphetamine in reducing DAT cross‐linking. In addition to overall similarities between the results with the two cross‐linking agents and between the results with the two different endocytosis inhibitors, some differences were noted as well, likely related to the efficiency of the cross‐linking process and the sulfhydryl‐reactive properties of phenylarsine oxide, respectively. The present results are the first to indicate regulation of oligomerization of an solute carrier family 6 transporter, the DAT, by substrates that act at DAT. In addition, the present study opens up the possibility of an important linkage between oligomerization of DAT and endocytic or other modulatory mechanisms impacting surface DAT.
Delayed neuronal preconditioning by NS1619 is independent of calcium activated potassium channels
Authors: Gáspár Tamás , Katakam Prasad , Snipes James A. , Kis Béla , Domoki Ferenc , Bari Ferenc , Busija David W. 
Published: March 2008

Abstract1,3‐Dihydro‐1‐[2‐hydroxy‐5‐(trifluoromethyl)phenyl]‐5‐(trifluoromethyl)‐2H‐benzimidazol‐2‐one (NS1619), a potent activator of the large conductance Ca2+ activated potassium (BKCa) channel, has been demonstrated to induce preconditioning (PC) in the heart. The aim of our study was to test the delayed PC effect of NS1619 in rat cortical neuronal cultures against oxygen‐glucose deprivation, H2O2, or glutamate excitotoxicity. We also investigated its actions on reactive oxygen species (ROS) generation, and on mitochondrial and plasma membrane potentials. Furthermore, we tested the activation of the phosphoinositide 3‐kinase (PI3K) signaling pathway, and the effect of NS1619 on caspase‐3/7. NS1619 dose‐dependently protected the cells against the toxic insults, and the protection was completely blocked by a superoxide dismutase mimetic and a PI3K antagonist, but not by BKCa channel inhibitors. Application of NS1619 increased ROS generation, depolarized isolated mitochondria, hyperpolarized the neuronal cell membrane, and activated the PI3K signaling cascade. However, only the effect on the cell membrane potential was antagonized by BKCa channel blockers. NS1619 inhibited the activation of capase‐3/7. In summary, NS1619 is a potent inducer of delayed neuronal PC. However, the neuroprotective effect seems to be independent of cell membrane and mitochondrial BKCa channels. Rather it is the consequence of ROS generation, activation of the PI3K pathway, and inhibition of caspase activation.
Purinergic receptor signaling regulates N‐cadherin expression in primary astrocyte cultures
Authors: Tran Minh D. , Wanner Ina B. , Neary Joseph T. 
Published: March 2008

AbstractExtracellular ATP exerts both short‐term and long‐term effects in the CNS by stimulating cell‐surface purinergic receptors. Here we have examined the effect of purinergic receptor activation on N‐cadherin expression, a calcium‐dependent cell adhesion molecule involved in many processes, including glia‐glia and axon‐glia interactions. When primary cultures of rat cortical astrocytes were treated with ATP, N‐cadherin protein expression increased in a time‐ and concentration‐dependent manner. In addition, ATP treatment caused an increase in N‐cadherin immunoreactivity in both the cytoplasm and on the cell surface membrane. Interestingly, experiments with cycloheximide revealed that relocalization of N‐cadherin to the cell surface membrane were independent of protein synthesis. The ATP‐induced increase in N‐cadherin protein expression was blocked by reactive blue 2 and 8‐(p‐sulfophenyl)‐theophylline, suggesting involvement of both P2 and P1 purinergic receptors, respectively. In addition, N‐cadherin expression was partially blocked when signaling from purinergic receptors to extracellular signal regulated protein kinase or Akt was inhibited by 1,4‐diamino‐2,3‐dicyano‐1,4‐bis(2‐aminophenylthio)butadiene or wortmannin, respectively. By using an in vitro model of traumatic CNS injury, we found that N‐cadherin expression was increased when astrocytes were subjected to rapid and reversible mechanical strain. The findings presented here demonstrate a role for extracellular ATP, purinergic receptors and protein kinase signaling in regulating N‐cadherin expression and suggest a role for this mechanism in cell‐cell interactions.
Role of autophagy in G2019S‐LRRK2‐associated neurite shortening in differentiated SH‐SY5Y cells
Authors: Plowey Edward D. , Cherra Salvatore J. , Liu Yong‐Jian , Chu Charleen T. 
Published: March 2008

AbstractNeuritic retraction represents a prominent feature of the degenerative phenotype associated with mutations in leucine rich repeat kinase 2 (LRRK2) that are implicated in autosomal dominant and some cases of sporadic Parkinson’s disease. Alterations in macroautophagy, the vacuolar catabolism of cytoplasmic constituents, have been described in Parkinson’s disease. In this study, we utilized retinoic‐acid differentiated SH‐SY5Y cells to determine whether autophagy contributes to mutant LRRK2‐associated neurite degeneration. Transfection of pre‐differentiated SH‐SY5Y cells with LRRK2 cDNA containing the common G2019S mutation resulted in significant decreases in neurite length, which were not observed in cells transfected with wild type LRRK2 or its kinase‐dead K1906M mutation. G2019S LRRK2 transfected cells also exhibited striking increases in autophagic vacuoles in both neuritic and somatic compartments, as demonstrated by fluorescence and western blot analysis of the autophagy marker green fluorescent protein‐tagged microtubule‐associated protein Light Chain 3 and by transmission electron microscopy. RNA interference knockdown of LC3 or Atg7, two essential components of the conserved autophagy machinery, reversed the effects of G2019S LRRK2 expression on neuronal process length, whereas rapamycin potentiated these effects. The mitogen activated protein kinase/extracellular signal regulated protein kinase (MAPK/ERK) kinase (MEK) inhibitor 1,4‐diamino‐2,3‐dicyano‐1,4‐bis[2‐aminophenylthio]butadiene (U0126) reduced LRRK2‐induced neuritic autophagy and neurite shortening, implicating MAPK/ERK‐related signaling. These results indicate an active role for autophagy in neurite remodeling induced by pathogenic mutation of LRRK2.
Xanthurenic acid distribution, transport, accumulation and release in the rat brain
Authors: Gobaille Serge , Kemmel Véronique , Brumaru Daniel , Dugave Christophe , Aunis Dominique , Maitre Michel 
Published: March 2008

AbstractTryptophan metabolism through the kynurenine pathway leads to several neuroactive compounds, including kynurenic and picolinic acids. Xanthurenic acid (Xa) has been generally considered as a substance with no physiological role but possessing toxic and apoptotic properties. In the present work, we present several findings which support a physiological role for endogenous Xa in synaptic signalling in brain. This substance is present in micromolar amounts in most regions of the rat brain with a heterogeneous distribution. An active vesicular synaptic process inhibited by bafilomycin and nigericin accumulates xanthurenate into pre‐synaptic terminals. A neuronal transport, partially dependant on adenosine 5′‐triphosphate (ATP), sodium and chloride ions exists in NCB‐20 neurons which could participate in the clearance of extracellular xanthurenate. Both transports (neuronal and vesicular) are greatly enhanced by the presence of micromolar amounts of zinc ions. Finally, electrical in vivo stimulation of A10‐induced Xa release in the extracellular spaces of the rat prefrontal cortex. This phenomenon is reproduced by veratrine, K+ ions and blocked by EGTA and tetrodotoxin. These results strongly argue for a role for Xa in neurotransmission/neuromodulation in the rat brain, thus providing the existence of specific Xa receptors.
Sustained saturating level of glycine induces changes in NR2B‐containing‐NMDA receptor localization in the CA1 region of the hippocampus
Authors: Imamura Yukio , Ma Chun‐Lei , Pabba Mohan , Bergeron Richard 
Published: March 2008

AbstractPost‐synaptic actions of glycine are terminated by specialized transporters. There are two genes encoding glycine transporters, GlyT1 and GlyT2. Glycine acts as a co‐agonist atN‐methyl‐d‐aspartate glutamatergic receptors (NMDARs). Blockage of GlyT1 enhances NMDAR function by controlling ambient glycine concentrations. Using whole‐cell patch‐clamp recordings of acute hippocampal slices, we investigated NMDAR kinetics of CA1 pyramidal neurons of mice expressing 50% of GlyT1 (GlyT1+/−). In this study, we report that the glycine modulatory site of the NMDAR at CA1 synapses is saturated in GlyT1+/− but not in wild‐type (WT) mice. We also found that the effect of ifenprodil, a highly selective NR2B‐containing‐NMDAR antagonist, is significantly reduced at CA1 synapses in GlyT1+/− compared to WT mice while immunoblotting experiments do not show significant differences for NR1, NR2A‐B‐C‐D subunits in both types of mice, suggesting alteration in NR2B‐containing‐NMDAR localization under a state of chronic saturating level of endogenous glycine. Using a pharmacological approach with MK‐801 and DL‐TBOA, we discriminated synapticvis‐à‐visextra‐synaptic NMDARs. We found that NR2B‐containing‐NMDARs are expressed at a higher level in the extra‐synaptic area of CA1 pyramidal neurons from GlyT1+/− compared to WT mice. Our results demonstrate that chronic saturating level of glycine induces significant changes in NMDAR localization and kinetic. Therefore, results from our study should help to gain a better understanding of the role of glycine in pathological conditions.
Characterization of signaling pathway for the translocation of neuronal nitric oxide synthase to the plasma membrane by PACAP
Authors: Ohnishi Takayuki , Okuda‐Ashitaka Emiko , Matsumura Shinji , Katano Tayo , Nishizawa Mikio , Ito Seiji 
Published: March 2008

AbstractIn the central nervous system, the activation of neuronal nitric oxide synthase (nNOS) is closely associated with activation of NMDA receptor, and trafficking of nNOS may be a prerequisite for efficient NO production at synapses. We recently demonstrated that pituitary adenylate cyclase activating polypeptide (PACAP) and NMDA synergistically caused the translocation of nNOS to the membrane and stimulated NO production in PC12 (pheochromocytoma) cells. However, the mechanisms responsible for trafficking and activation of nNOS are largely unknown. To address these issues, here we constructed a yellow fluorescent protein (YFP)‐tagged nNOS N‐terminal (1–299 a.a.) mutant, nNOSNT‐YFP, and visualized its translocation in PC12 cells stably expressing it. PACAP enhanced the translocation synergistically with NMDA in a time‐ and concentration‐dependent manner. The translocation was blocked by inhibitors of protein kinase A (PKA), protein kinase C (PKC), and Src kinase; and the effect of PACAP could be replaced with PKA and PKC activators. The β‐finger region in the PSD‐95/disc large/zonula occludens‐1 domain of nNOS was required for the translocation of nNOS and its interaction with post‐synaptic density‐95 (PSD‐95), and NO formation was attenuated by dominant negative nNOSNT‐YFP. These results demonstrate that PACAP stimulated nNOS translocation mediated by PKA and PKC via PAC1‐receptor (a PACAP receptor) and suggest cross‐talk between PACAP and NMDA for nNOS activation by Src‐dependent phosphorylation of NMDA receptors.
Helicobacter pylori Genotyping and Sequencing Using Paraffin‐Embedded Biopsies from Residents of Colombian Areas with Contrasting Gastric Cancer Risks
Authors: Sicinschi Liviu A. , Correa Pelayo , Peek Richard M. , Camargo M. Constanza , Delgado Alberto , Piazuelo M. Blanca , Romero‐Gallo Judith , Bravo Luis E. , Schneider Barbara G. 
Published: March 2008

AbstractBackground:   cagA‐positive and vacA s1 and m1 genotypes of Helicobacter pylori are associated with an elevated risk of gastric cancer (GC). We determined these genotypes using paraffin‐embedded gastric biopsy specimens harvested from infected individuals and compared genotype distributions in two Colombian populations residing in geographic regions with a high and low incidence of GC.Methods:   DNA from paraffin‐embedded gastric biopsies from 107 adults was amplified using primers specific for cagA, for the cag‘empty site’, for the s and m alleles of vacA, and for H. pylori 16S rRNA.Results:   H. pylori infection was detected by molecular assays in 97 (90.7%) biopsies. Complete genotyping of cagA and vacA was achieved in 94 (96.9%) cases. The presence of cagA was detected in 78 of 97 cases (80.4%); when considered separately, cagA and vacA s regions were not significantly associated with a particular geographic area. The vacA m1 allele and s1m1 genotypes were more common in the area of high risk for GC (p = .037 and p = .044, respectively), while the vacA m2 allele and s2m2 genotypes were more prevalent in the low‐risk area. The prevalence of the combination of cagA‐positive, vacA s1m1 genotypes was 84.3% and 60.5% for high and low risk areas, respectively (p = .011).Conclusions:  H. pylori cagA and vacA genotyping from paraffin‐embedded gastric biopsies permitted reliable typability and discrimination. The more virulent cagA‐positive s1m1 strains, as well as vacA m1 genotype, were more prevalent in high risk than in low risk areas, which may contribute to the difference in GC risk between those two regions.
Four Modes of Adhesion are Used During Helicobacter pylori Binding to Human Mucins in the Oral and Gastric Niches
Authors: Lindén Sara K. , Wickström Claes , Lindell Gert , Gilshenan Kristen , Carlstedt Ingemar 
Published: March 2008

AbstractBackground:  Helicobacter pylori causes peptic ulcer disease and gastric cancer, and the oral cavity is likely to serve as a reservoir for this pathogen. We investigated the binding of H. pylori to the mucins covering the mucosal surfaces in the niches along the oral to gastric infection route and during gastric disease and modeled the outcome of these interactions.Materials and Methods:  A panel of seven H. pylori strains with defined binding properties was used to identify binding to human mucins from saliva, gastric juice, cardia, corpus, and antrum of healthy stomachs and of stomachs affected by gastritis at pH 7.4 and 3.0 using a microtiter‐based method.Results:  H. pylori binding to mucins differed substantially with the anatomic site, mucin type, pH, gastritis status, and H. pylori strain all having effect on binding. Mucins from saliva and gastric juice displayed the most diverse binding patterns, involving four modes of H. pylori adhesion and the MUC5B, MUC7, and MUC5AC mucins as well as the salivary agglutinin. Binding occurred via the blood‐group antigen‐binding adhesin (BabA), the sialic acid‐binding adhesin (SabA), a charge/low pH‐dependent mechanism, and a novel saliva‐binding adhesin. In the healthy gastric mucus layer only BabA and acid/charge affect binding to the mucins, whereas in gastritis, the BabA/Leb‐dependent binding to MUC5AC remained, and SabA and low pH binding increased.Conclusions:  The four H. pylori adhesion modes binding to mucins are likely to play different roles during colonization of the oral to gastric niches and during long‐term infection.
Leptin Receptor Signaling is Required for Vaccine‐Induced Protection Against Helicobacter pylori
Authors: Wehrens Andrea , Aebischer Toni , Meyer Thomas F. , Walduck Anna K. 
Published: March 2008

AbstractBackground:  A vaccine against Helicobacter pylori would be a desirable alternative to antibiotic therapy. Vaccination has been shown to be effective in animal models but the mechanism of protection is poorly understood. Previous studies investigating the gene expression in stomachs of vaccinated mice showed changes in adipokine expression correlated to a protective response. In this study, we investigate a well‐characterized adipokine‐leptin, and reveal an important role for leptin receptor signaling in vaccine‐induced protection.Materials and Methods:  Leptin receptor signaling‐deficient (C57BL/Ks Leprdb), wild‐type C57BL/Ks m littermates and C57BL/6 mice were vaccinated, and then challenged with H. pylori. Levels of bacterial colonization, antibody levels, and gastric infiltrates were compared. The local gene expression pattern in the stomach of leptin receptor signaling‐deficient and wild‐type mice was also compared using microarrays.Results:  Interestingly, while vaccinated wild‐type lean C57BL/6 and C57BL/Ks m mice were able to significantly reduce colonization compared to controls, vaccinated obese C57BL/Ks Leprdb were not. All mice responded to vaccination, i.e. developed infiltrates predominantly of T lymphocytes in the gastric mucosa, and made H. pylori‐specific antibodies. A comparison of expression profiles in protected C57BL/6 and nonprotected C57BL/Ks Leprdb mice revealed a subset of inflammation‐related genes that were more strongly expressed in nonprotected mice.Conclusions:  Our data suggest that functional leptin receptor signaling is required for mediating an effective protective response against H. pylori.
Associations Between Vitamin D Status and Pain in Older Adults: The Invecchiare in Chianti Study
Authors: Hicks Gregory E. , Shardell Michelle , Miller Ram R. , Bandinelli Stefania , Guralnik Jack , Cherubini Antonio , Lauretani Fulvio , Ferrucci Luigi 
Published: March 2008

OBJECTIVES: To examine cross‐sectional associations between vitamin D status and musculoskeletal pain and whether they differ by sex.DESIGN: Population‐based study of persons living in the Chianti geographic area (Tuscany, Italy).SETTING: Community.PARTICIPANTS: Nine hundred fifty‐eight persons (aged ≥65) selected from city registries of Greve and Bagno a Ripoli.MEASUREMENTS: Pain was categorized as mild or no pain in the lower extremities and back; moderate to severe back pain, no lower extremity pain; moderate to severe lower extremity pain, no back pain; and moderate to severe lower extremity and back pain (dual region). Vitamin D was measured according to radioimmunoassay, and deficiency was defined as 25‐hydroxyvitamin D (25(OH)D) less than 25 nmol/L.RESULTS: The mean age±standard deviation was 75.1±7.3 for women and 73.9±6.8 for men. Fifty‐eight percent of women had at least moderate pain in some location, compared with 27% of men. After adjusting for potential confounders, vitamin D deficiency was not associated with lower extremity pain or dual‐region pain, although it was associated with a significantly higher prevalence of at least moderate back pain without lower extremity pain in women (odds ratio=1.96, 95% confidence interval=1.01–3.59) but not in men.CONCLUSION: Lower concentrations of 25(OH)D are associated with significant back pain in older women but not men. Because vitamin D deficiency and chronic pain are fairly prevalent in older adults, these findings suggest it may be worthwhile to query older adults about their pain and screen older women with significant back pain for vitamin D deficiency.
Do Financial Incentives of Introducing Case Mix Reimbursement Increase Feeding Tube Use in Nursing Home Residents?
Authors: Teno Joan M. , Feng Zhanlian , Mitchell Susan L. , Kuo Sylvia , Intrator Orna , Mor Vincent 
Published: March 2008

OBJECTIVES: To determine whether adoption of Medicaid case mix reimbursement is associated with greater prevalence of feeding tube use in nursing home (NH) residents.DESIGN: Secondary analysis of longitudinal administrative data about the prevalence of feeding tube insertion and surveys of states' adoption of case mix reimbursement.SETTING: NHs in the United States.PARTICIPANTS: NH residents at the time of NH inspection between 1993 and 2004.MEASUREMENTS: Facility prevalence of feeding tubes reported at the state inspection of NHs reported in the Online Survey, Certification and Reporting database and interviews with state policy makers regarding the adoption of case mix reimbursement.RESULTS: Between 1993 and 2004, 16 states adopted Resource Utilization Group case mix reimbursement. States varied in the prevalence of feeding tubes in their NHs. Although the use of feeding tube increased substantially over the years of the study, once temporal trends and facility fixed effects were accounted for, case mix reimbursement was not associated with greater prevalence of feeding tube use.CONCLUSION: The adoption of Medicaid case mix reimbursement was not associated with an increase in the prevalence of feeding tube use.
Immunohistochemical characterization of guided bone regeneration at a dehiscence‐type defect using different barrier membranes: an experimental study in dogs
Authors: Schwarz Frank , Rothamel Daniel , Herten Monika , Wüstefeld Martin , Sager Martin , Ferrari Daniel , Becker Jürgen 
Published: March 2008

AbstractObjectives: The aim of the present study was to evaluate immunohistochemically the pattern of guided bone regeneration (GBR) using different types of barrier membranes.Material and methods: Standardized buccal dehiscence defects were surgically created following implant bed preparation in 12 beagle dogs. Defects were randomly assigned to six different GBR procedures: a collagen‐coated bone grafting material (BOC) in combination with either a native, three cross‐linked, a titanium‐reinforced collagen membrane, or expanded polytetrafluorethylene (ePTFE), or BOC alone. After 1, 2, 4, 6, 9, and 12 weeks of submerged healing, dissected blocks were processed for immunohistochemical (osteocalcin – OC, transglutaminase II – angiogenesis) and histomorphometrical analysis [e.g., bone‐to‐implant contact (BIC), area of new bone fill (BF)].Results: In general, angiogenesis, OC antigen reactivity, and new bone formation mainly arose from open bone marrow spaces at the bottom of the defect and invaded the dehiscence areas along the implant surface and BOC. At 4 weeks, membranes supporting an early transmembraneous angiogenesis also exhibited some localized peripheral areas of new bone formation. However, significantly increasing BIC and BF values over time were observed in all groups. Membrane exposure after 10–12 weeks was associated with a loss of the supporting alveolar bone in the ePTFE group.Conclusion: Within the limits of the present study, it was concluded that (i) angiogenesis plays a crucial role in GBR and (ii) all membranes investigated supported bone regeneration on an equivalent level.