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  • 1
    Electronic Resource
    Electronic Resource
    Role of the Compact Node and Its Posterior Extension in Normal Atrioventricular Nodal Conduction, Refractory, and Dual Pathway Properties (1999)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of cardiovascular electrophysiology 10 (1999), S. 0 
    Details
    ISSN: 1540-8167
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: AV Nodal Conduction and Dual Pathways. Introduction: The functional origin of AV nodal conduction, refractory, and dual pathway properties remains debated. The hypothesis that normal conduction and refractory properties of the compact node and its posterior nodal extension (PNE) play a critical role in the slow and the fast pathway, respectively, is tested with ablation lesions targeting these structures. Methods and Results: A premature atrial stimulation protocol was performed before and after PNE ablation in six isolated rabbit heart preparations. Discrete (〈300 μm) histologically controlled PNE lesions amputated the AV nodal recovery curve from its left steep portion reflecting slow pathway conduction and prevented reentry without affecting the right smooth fast pathway portion of the curve. The ablation shortened A2H2max from 159 ± 16 ms to 123 ± 11 msec (P 〈 0.01) and prolonged the effective refractory period from 104 ± 6 msec to 119 ± 11 msec (P 〈 0.01) without affecting A2H2 min (55 ± 9 msec vs 55 ± 8 msec; P = NS) and functional refractory period (174 ± 7 msec vs 175 ± 6 msec; P = NS). These results did not vary with the input reference used. In six other preparations, lesions applied to the compact node after PNE ablation shifted the fast pathway portion of the recovery curve to longer conduction times and prolonged the functional refractory period, suggesting a compact node involvement in the fast pathway. Conclusion: The normal AV nodal conduction and refractory properties reflect the net result of the interaction between a slow and a fast pathway, which primarily arise from the asymmetric properties of the PNE and compact node, respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1540-8167.1999.tb00203.x
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  • 2
    Electronic Resource
    Electronic Resource
    Characteristics, Circuit, Mechanism, and Ablation of Reentry in the Rabbit Atrioventricular Node (1999)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of cardiovascular electrophysiology 10 (1999), S. 0 
    Details
    ISSN: 1540-8167
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Functional Origin of AV Nodal Reentry. Introduction: The circuitry underlying AV nodal reentry remains debated. We developed a model of AV nodal reentry and assessed the role of nodal inputs, compact node, and its posterior nodal extension (PNE) in this phenomenon. Methods and Results: A fine scanning of short coupling interval range with an atrial premature heat consistently initiated slow-fast AV nodal reentrant heats that occurred 37 ± 31 msec (mean ± SD) after His-bundle activation in 11 of 16 consecutive rabbit heart preparations. The repeated testing (〉40 times) of a chosen coupling interval within reentry window (6 ± 9 msec, n = 11) yielded reentrant intervals that varied by 2 ± 1 msec (mean SD for 40 heats ± SD, n = 11). The breakthrough point of reentrant activation, as assessed from four perinodal sites, varied in different preparations from diffuse (4) to anterior (1), medial (3), or posterior (3); mean reentrant interval did not differ between perinodal sites. Antegrade perinodal activation pattern did not differ at reentrant versus nonreentrant coupling intervals and thus was not a primary determinant of reentry. A PNE ablation (n = 4) interrupted the slow pathway conduction and prevented reentry without affecting antegrade perinodal activation or fast pathway conduction. Conclusion: A reproducible model of AV nodal reentrant beats was developed and used to study underlying circuitry. The AV nodal reentry involves unaltered antegrade perinodal activation, slow PNE conduction and retrograde broad invasion of perinodal tissues starting at a preparation-dependent breakthrough point. A PNE ablation abolishes the reentry.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1540-8167.1999.tb01266.x
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  • 3
    Electronic Resource
    Electronic Resource
    Synthesis of a Visible-Light Active TiO2−xSx Photocatalyst by Means of Mechanochemical Doping (2004)
    Westerville, Ohio : American Ceramics Society
    Journal of the American Ceramic Society 87 (2004), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: A visible-light active TiO2−xSx in rutile structure has been synthesized by means of a mechanochemical method. The method is composed of two steps: the first is grinding the mixture of sulfur and TiO2, and the second is calcining the ground sample at 673 K in an inert gas flow. XPS analysis confirms that sulfur has been successfully doped into TiO2. The calcined sample under irradiation of visible light with wave-length over 510 nm has shown good performance for NO gas destruction, suggesting its high photograph-reactivity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1551-2916.2004.01161.x
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  • 4
    Electronic Resource
    Electronic Resource
    G Protein-Coupled Cyclic AMP Signaling in Postmortem Brain of Subjects with Mood Disorders (1999)
    Oxford UK : Blackwell Science Ltd
    Journal of neurochemistry 73 (1999), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract : Components of cyclic AMP (cAMP) signaling were examined in postmortem cerebral cortex of a well characterized group of patients with mood disorders and nonpsychiatric control subjects. We measured G protein levels, adenylyl cyclase (AC) activity, and CREB levels in cerebral cortex of the subjects with respect to diagnosis, treatment, and suicide. There was no effect of diagnosis on any measure, except for a trend toward decreased stimulated AC activity in subjects with mood disorders relative to control subjects. We also detected a significant effect of suicide on temporal cortex CREB levels in subjects that died as a result of suicide relative to those that did not, which was more evident in patients with major depressive disorder. Bipolar disorder (BD) subjects treated with anticonvulsants at the time of death had decreased temporal cortex CREB levels relative to those not receiving anticonvulsants. Furthermore, we found a trend toward decreased occipital cortex GαS (short) levels in BD subjects treated with lithium. These results support the hypothesis of altered cAMP signaling in mood disorders and raise the possibility that factors other than diagnosis, such as treatment and suicide, may be relevant to cell-signaling abnormalities reported in the literature.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1471-4159.1999.0731121.x
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  • 5
    Electronic Resource
    Electronic Resource
    Gene expression differences in bipolar disorder revealed by cDNA array analysis of post-mortem frontal cortex (2001)
    Oxford, UK : Blackwell Science Ltd
    Journal of neurochemistry 79 (2001), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Previous studies have implicated a number of biochemical pathways in the etiology of bipolar disorder (BD). However, the precise abnormalities underlying this disorder remain to be established. To investigate novel factors that may be important in the pathophysiology of BD, we utilized cDNA expression arrays to examine differences in expression of up to 1200 genes known to be involved in potentially relevant biochemical processes. This investigation was undertaken in post-mortem samples of frontal cortex tissue from patients with BD and matched controls, obtained (n = 10/group) from the Stanley Foundation Neuropathology Consortium. Results include significant (greater than 35% change in signal intensity) differences between BD and controls in a number of genes (n = 24). Selected targets were analyzed by RT-PCR, which confirmed a decrease in transforming growth factor-beta1 (TGF-β1), and an increase in both caspase-8 precursor (casp-8) and transducer of erbB2 (Tob) expression in BD. We further observed a significant decrease of TGF-β1 mRNA levels in BD by RT-PCR in individual post-mortem samples. Given the neuroprotective role attributed to this inhibitory cytokine, our results suggest that the down-regulation of TGF-β1 may lead to various neurotoxic insults potentially involved in the etiology of certain mood disorders.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1471-4159.2001.00628.x
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  • 6
    Electronic Resource
    Electronic Resource
    Unbleachable rhodopsin with an 11-cis-locked eight-membered ring retinal: The visual transduction process. [Erratum to document cited in CA120(7):74157z] (1994)
    s.l. : American Chemical Society
    Biochemistry 33 (1994), S. 4994-4994 
    Details
    ISSN: 1520-4995
    Source: ACS Legacy Archives
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/bi00182a030
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  • 7
    Electronic Resource
    Electronic Resource
    Sp1 and Sp3 activate transcription of the human dopamine transporter gene (2005)
    Oxford, UK : Blackwell Science Ltd
    Journal of neurochemistry 93 (2005), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The dopamine transporter is a plasma membrane protein that controls extracellular concentrations of the neurotransmitter dopamine. The physiological importance of the DAT provides the impetus for studies aimed at understanding the molecular mechanisms underlying regulation of the DAT gene. In this study, we identified a DAT-expressing neuroblastoma cell line (SK-N-AS) and employed it to investigate the transcriptional regulation of the human DAT gene. Two GC boxes (located at −130 and −60, respectively, relative to the transcriptional start site) were identified as important cis-acting elements mediating DAT promoter activity in dopaminergic SK-N-AS cells. Utilizing Sp-deficient Drosophila Schneider line (SL-2) cells, we showed that both Sp1 and Sp3 are strong activators of DAT transcriptional activity. Differential binding of Sp1 and Sp3 to the two GC boxes was demonstrated by electrophoretic mobility shift assays and super-shift assays. Our results indicate that the Sp1 family of proteins plays an important role in controlling the expression of the dopamine transporter gene within dopaminergic neurons.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-4159.2005.03051.x
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  • 8
    Electronic Resource
    Electronic Resource
    Glutathione S-transferase is a novel target for mood stabilizing drugs in primary cultured neurons (2004)
    Oxford, UK : Blackwell Science Ltd
    Journal of neurochemistry 88 (2004), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Oligonucleotide microarray technology was used to analyze gene expression profiles after chronic treatment with the mood stabilizing drug valproate at a therapeutically relevant concentration in primary cultured rat cerebral cortical cells. We discovered that valproate regulates expression of 28 genes, including three isoenzymes (M1, A3 and A4) of glutathione S-transferase (GST), an important protective factor against oxidative stress. Because previous studies in our laboratory found that chronic valproate treatment protected cultured neurons against oxidative stress, further experiments on the regulation of GST were performed. Regulation of GST M1, GST A3 and GST A4 was verified using northern blotting hybridization. Chronic valproate treatment increased mRNA levels of M1 and A4, but decreased the A3 mRNA level dose-dependently, indicating further complexities in the regulation of GST by valproate. The level of GST M1 protein and GST activity were also increased by chronic valproate treatment. In addition, chronic treatment with lithium, another commonly prescribed mood stabilizer, also increased levels of GST M1 mRNA and protein. The present findings suggest that regulation of GST M1, and possibly GST A4, may mediate the anti-oxidative effects of valproate treatment, and regulation of GST may be involved in the mood stabilizing effect of valproate and lithium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1471-4159.2003.02276.x
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  • 9
    Electronic Resource
    Electronic Resource
    Dopamine neurons express multiple isoforms of the nuclear receptor nurr1 with diminished transcriptional activity (2005)
    Oxford, UK : Blackwell Science Ltd
    Journal of neurochemistry 95 (2005), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Nurr1 (NR4A2) is an orphan nuclear receptor required for the development and maintenance of the dopaminergic phenotype in neurons of the ventral midbrain. This study demonstrates that multiple splice variants of nurr1 are produced in rat and human dopamine neurons. Formed by alternative RNA splicing in exon 7, nurr1a has a truncated carboxy-terminus, nurr1b has an internal deletion in the ligand-binding domain and nurr1c, newly identified in this study, has a novel carboxy-terminus produced by a frame shift downstream of the splice junction. Alternative RNA splicing in exon 3 produces the isoform known as the transcriptionally-inducible nuclear receptor (TINUR), lacking the amino-terminus. Nurr2 and the newly identified nurr2c are produced by utilization of both exon 3 and exon 7 alternative splice sites. In rat midbrain, variants other than full-length nurr1 constitute 20–35% of NR4A2 transcripts. Transfection studies in dopaminergic SK-N-AS cells demonstrate that nurr1a, nurr1b, nurr1c and TINUR have significantly reduced transcriptional activities compared with full-length nurr1, while nurr2 and nurr2c are inactive. Furthermore, in these experiments, nurr2 and nurr2c both act as dominant negatives. Production of these nurr1 variants in vivo as demonstrated here could represent a novel regulatory mechanism of nurr1 transcriptional activity and therefore, dopaminergic phenotype.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-4159.2005.03458.x
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  • 10
    Electronic Resource
    Electronic Resource
    Binding and diffusion of a Si adatom around the type A step on Si(001) c(4×2) (1995)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 66 (1995), S. 1954-1956 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The results of a simulation are described, using a density functional method, of the diffusion of adatoms on a flat Si(001)c(4×2) surface and around one type of surface step (the SA step). These indicate that there is a moderate additional energy barrier (0.2±0.1 eV) to cross the SA step as compared to the energy for diffusion on a flat surface. The dimer-top lattice site on the lower terrace adjacent to the step edge is stabilized (by 0.15±0.1 eV) with respect to the flat surface result although the most stable binding sites near the step are unaffected. This behavior can be understood based on the disruption of dimer tilt near the step. The results suggest that adatoms are more likely to stop on lattice sites at the SA step edge than on lattice sites on the open surface. This may affect the relative dimer formation rate near the step with respect to the behavior on the flat surface even in the absence of a clear change in binding energy. The effect of the SA step terrace edge on adatom behavior is very short ranged and weak. This is consistent with the relatively small strain field and lack of change in dangling bond density associated with the step edge. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.113288
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