bluuebunny/crossref_metadata_2025 huggingface dataset:
Different effects of arsenate and phosphonoformate on Pi transport adaptation in opossum kidney cells
Authors: Villa-Bellosta Ricardo , Sorribas Víctor
Published: June 2009

The main nonhormonal mechanism for controlling inorganic phosphate (Pi) homeostasis is renal adaptation of the proximal tubular Pi transport rate to changes in dietary phosphate content. Opossum kidney (OK) cell line is an in vitro renal model that maintains the ability of renal adaptation to the extracellular Pi concentration. We have studied how two competitive inhibitors of Pi transport, arsenate [As(V)] and phosphonoformate (PFA), affect adaptation to low and high Pi concentrations. OK cells show very high affinity for As(V) (inhibitory constant, Ki 0.12 mM) when compared with the rat kidney. As(V) very efficiently reversed the adaptation of OK cells to low Pi (0.1 mM), whereas PFA induced adaptation similar to 0.1 mM Pi. Adaptation with 2 mM Pi or As(V) was characterized by decreases in the maximal velociy ( Vmax) of Pi transport and an abundance of the NaPi-IIa Pi transporter in the plasma membrane, shown by the protein biotinylation. Conversely, PFA and 0.1 mM Pi increased the Vmax and transporter abundance. Changes in the Vmax were limited to a 50% variation, which was not paralleled by changes in the concentration of Pi or of the inhibitor. OK cells are very sensitive to As(V), but the effects are reversible and noncytotoxic. These effects can be interpreted as As(V) being transported into the cell, thereby mimicking a high Pi concentration. PFA blocks the uptake of Pi but is not transported, and it therefore simulates a low Pi concentration inside the cell. To conclude, a mathematical definition of the adaptation process is reported, thereby explaining the limited changes in Pi transport Vmax.
PGC-1α attenuates neointimal formation via inhibition of vascular smooth muscle cell migration in the injured rat carotid artery
Authors: Qu Aijuan , Jiang Changtao , Xu Mingjiang , Zhang Yan , Zhu Yi , Xu Qingbo , Zhang Chenyu , Wang Xian
Published: June 2009

Oxidative stress contributes significantly to the migration of vascular smooth muscle cells (VSMCs), the major pathogenic process of vascular diseases, but the mechanism remains unclear. In the present study, we explored the role of peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α), a major regulator of mitochondrial biogenesis and energy balance, in VSMC migration in vitro and in vivo. Overexpression of PGC-1α in cultured VSMCs led to a 74.5% reduction of migration activity and mitochondrial ROS generation by the increased expression of antioxidative proteins such as SOD-2 in the mitochondria. The knockdown of PGC-1α by specific small interfering (si)RNA markedly augmented VSMC migration activity and greatly reduced mitochondrial antioxidative protein expression. Furthermore, knockdown of SOD-2 expression by siRNA greatly reversed the inhibitory effect of PGC-1α overexpression on VSMC migration. In a rat carotid balloon injury model, adenovirus-mediated overexpression of PGC-1α greatly reduced neointimal formation (ratio of intima to media: 0.78 ± 0.09 vs. 1.45 ± 0.18 in the adenovirus + green fluorescent protein gene- transfected group). Moreover, the expression of SOD-2 was significantly increased in vivo in local vessels after injury in the PGC-1α-overexpressing group. These data strongly suggest that PGC-1α inhibits VSMC migration and neointimal formation after vascular injury in rats, mainly by upregulating the expression of the mitochondrial antioxidant enzyme SOD-2.
FoxO1 induces apoptosis in skeletal myotubes in a DNA-binding-dependent manner
Authors: McLoughlin Thomas J. , Smith Sierra M. , DeLong Alissa D. , Wang Hengbing , Unterman Terry G. , Esser Karyn A.
Published: June 2009

Recent studies indicate that FoxO transcription factors play an important role in promoting muscle atrophy. To study mechanisms mediating effects of FoxO proteins on muscle wasting, FoxO1-estrogen receptor fusion proteins that are activated by treatment with 4-hydroxytamoxifen (4-OH-T) were stably transfected in C2C12 skeletal myoblasts using the pBABE retroviral system and grown into multinucleated skeletal myotubes. Activation of FoxO1 resulted in significant muscle atrophy, which was accompanied by DNA fragmentation, evidenced by terminal deoxynucleotidyl transferase dUTP-mediated nick end labeling. Cells expressing a DNA-binding-deficient form of FoxO1 also exhibited significant atrophy on FoxO1 activation but no hallmark signs of apoptosis. FoxO1 activation resulted in a significant increase in muscle atrophy F-box (MAFbx)/atrogin-1, muscle-specific RING finger protein 1 (MuRF-1), and Bcl-2-interacting mediator of cell death (Bim) gene expression, with no significant increase in Bcl-2/adenovirus E1B 19-kDa-interacting protein 3 (BNip3) gene expression. Although the ability of FoxO1 to induce MuRF-1 gene expression appeared to be independent of DNA binding, expression of MAFbx/atrogin-1 and Bim was significantly blunted in cells expressing DNA-binding-deficient FoxO1. BNip3 gene expression was significantly elevated in DNA-binding-deficient mutant cells. These findings indicate that FoxO1 promotes skeletal muscle atrophy through induction of proteolytic and apoptotic machinery via DNA-binding-dependent and -independent mechanisms.
Slow synaptic transmission in myenteric AH neurons from the inflamed guinea pig ileum
Authors: Nurgali Kulmira , Nguyen Trung V. , Thacker Michelle , Pontell Louise , Furness John B.
Published: June 2009

We investigated the effect of inflammation on slow synaptic transmission in myenteric neurons in the guinea pig ileum. Inflammation was induced by the intraluminal injection of trinitrobenzene sulfonate, and tissues were taken for in vitro investigation 6–7 days later. Brief tetanic stimulation of synaptic inputs (20 Hz, 1 s) induced slow excitatory postsynaptic potentials (EPSPs) in 49% and maintained postsynaptic excitation that lasted from 27 min to 3 h in 13% of neurons from the inflamed ileum. These neurons were classified electrophysiologically as AH neurons; 10 were morphological type II neurons, and one was type I. Such long-term hyperexcitability after a brief stimulus is not encountered in enteric neurons of normal intestine. Electrophysiological properties of neurons with maintained postsynaptic excitation were similar to those of neurons with slow EPSPs. Another form of prolonged excitation, sustained slow postsynaptic excitation (SSPE), induced by 1-Hz, 4-min stimulation, in type II neurons from the inflamed ileum reached its peak earlier but had lower amplitude than that in control. Unlike slow EPSPs and similar to SSPEs, maintained excitation was not inhibited by neurokinin-1 or neurokinin-3 receptor antagonists. Maintained postsynaptic excitation was not influenced by PKC inhibitors, but the PKA inhibitor, H-89, caused further increase in neuronal excitability. In conclusion, maintained excitation, observed only in neurons from the inflamed ileum, may contribute to the dysmotility, pain, and discomfort associated with intestinal inflammation.
Electrophysiological responses of sympathetic preganglionic neurons to ANG II and aldosterone
Authors: Minoura Yoshino , Onimaru Hiroshi , Iigaya Kamon , Homma Ikuo , Kobayashi Youichi
Published: June 2009

The intermediolateral cell column (IML) of the spinal cord is an important area where sympathetic impulses propagate to peripheral sympathetic organs. ANG II and aldosterone are important components of the renin-angiotensin-aldosterone system (RAAS), which activate the sympathetic nervous system. Each is partly synthesized in the brain and plays a paracrine role in the regulation of blood pressure independently of RAAS in the periphery. Our purpose in the present study was to clarify the contributions of sympathetic preganglionic neurons in the IML (IML neurons) and the effects of ANG II and aldosterone on the sympathetic nervous system. To examine responses to ANG II and aldosterone, we intracellularly recorded 104 IML neurons using a whole cell patch-clamp technique in spinal cord slice preparations. IML neurons were classified into two types: silent and firing. Both neuron types were significantly depolarized by ANG II, and candesartan inhibited this depolarization. After pretreatment with TTX, firing neurons (but not silent neurons) were significantly depolarized by ANG II. Aldosterone significantly increased the number of excitatory postsynaptic potentials (EPSPs) in both neuron types, but this response disappeared after pretreatment with TTX. ANG II and aldosterone had no synergistic effects on the IML neurons. The silent neurons had large cell soma, and many more dendrites than the firing neurons. These results suggest that ANG II acts presynaptically and postsynaptically in IML neurons, while aldosterone acts mainly presynaptically. Thus, the physiological effects of these substances are likely to be transmitted via specific membrane receptors of IML and/or presynaptic neurons.
Neuronostatin inhibits cardiac contractile function via a protein kinase A- and JNK-dependent mechanism in murine hearts
Authors: Hua Yinan , Ma Heng , Samson Willis K. , Ren Jun
Published: June 2009

Neuronostatin, a newly identified peptide hormone sharing the same precursor with somatostatin, exerts multiple pharmacological effects in gastrointestinal tract, hypothalamus, and cerebellum. However, the cardiovascular effect of neuronostatin is unknown. The aim of this study was to elucidate the impact of neuronostatin on cardiac contractile function in murine hearts and isolated cardiomyocytes. Short-term exposure of neuronostatin depressed left ventricular developed pressure (LVDP), maximal velocity of pressure development (±dP/d t), and heart rate in Langendorff heart preparation. Consistently, neuronostatin inhibited peak shortening (PS) and maximal velocity of shortening/relengthening (±dL/d t) without affecting time-to-PS (TPS) and time-to-90% relengthening (TR90) in cardiomyocytes. The neuronostatin-elicited cardiomyocyte mechanical responses were mimicked by somatostatin, the other posttranslational product of preprosomatostatin. Furthermore, the neuronostatin-induced cardiomyocyte mechanical effects were ablated by the PKA inhibitor H89 (1 μM) and the Jun N-terminal kinase (JNK) inhibitor SP600125 (20 μM). The PKC inhibitor chelerythrine (1 μM) failed to alter neuronostatin-induced cardiomyocyte mechanical responses. To the contrary, chelerythrine, but not H89, abrogated somatostatin-induced cardiomyocyte contractile responses. Our results also showed enhanced c-fos and c-jun expression in response to neuronostatin exposure (0.5 to 2 h). Taken together, our data suggest that neuronostatin is a peptide hormone with overt cardiac depressant action. The neuronostatin-elicited cardiac contractile response appears to be mediated, at least in part, through a PKA- and/or JNK-dependent mechanism.
Pressure-induced constriction is inhibited in a mouse model of reduced βENaC
Authors: VanLandingham Lauren G. , Gannon Kimberly P. , Drummond Heather A.
Published: June 2009

Recent studies suggest certain epithelial Na+channel (ENaC) proteins may be components of mechanosensitive ion channel complexes in vascular smooth muscle cells that contribute to pressure-induced constriction in middle cerebral arteries (MCA). However, the role of a specific ENaC protein, βENaC, in pressure-induced constriction of MCAs has not been determined. The goal of this study was to determine whether pressure-induced constriction in the MCA is altered in a mouse model with reduced levels of βENaC. Using quantitative immunofluorescence, we found whole cell βENaC labeling in cerebral vascular smooth muscle cells (VSMCs) was suppressed 46% in βENaC homozygous mutant (m/m) mice compared with wild-type littermates (+/+). MCAs from βENaC +/+ and m/m mice were isolated and placed in a vessel chamber for myographic analysis. Arteries from βENaC+/+ mice constricted to stepwise increases in perfusion pressure and developed maximal tone of 10 ± 2% at 90 mmHg ( n = 5). In contrast, MCAs from βENaC m/m mice developed significantly less tone (4 ± 1% at 90 mmHg, n = 5). Vasoconstrictor responses to KCl (4–80 mM) were identical between genotypes and responses to phenylephrine (10−7-10−4M) were marginally altered, suggesting that reduced levels of VSMC βENaC specifically inhibit pressure-induced constriction. Our findings indicate βENaC is required for normal pressure-induced constriction in the MCA and provide further support for the hypothesis that βENaC proteins are components of a mechanosensor in VSMCs.
Chronic ethanol attenuates circadian photic phase resetting and alters nocturnal activity patterns in the hamster
Authors: Ruby Christina L. , Brager Allison J. , DePaul Marc A. , Prosser Rebecca A. , Glass J. David
Published: June 2009

Acute ethanol (EtOH) administration impairs circadian clock phase resetting, suggesting a mode for the disruptive effect of alcohol abuse on human circadian rhythms. Here, we extend this research by characterizing the chronobiological effects of chronic alcohol consumption. First, daily profiles of EtOH were measured in the suprachiasmatic nucleus (SCN) and subcutaneously using microdialysis in hamsters drinking EtOH. In both cases, EtOH peaked near lights-off and declined throughout the dark-phase to low day-time levels. Drinking bouts preceded EtOH peaks by ∼20 min. Second, hamsters chronically drinking EtOH received a light pulse during the late dark phase [Zeitgeber time (ZT) 18.5] to induce photic phase advances. Water controls had shifts of 1.2 ± 0.2 h, whereas those drinking 10% and 20% EtOH had much reduced shifts (0.5 ± 0.1 and 0.3 ± 0.1 h, respectively; P < 0.001 vs. controls). Third, incremental decreases in light intensity (270 lux to 0.5 lux) were used to explore chronic EtOH effects on photic entrainment and rhythm stability. Activity onset was unaffected by 20% EtOH at all light intensities. Conversely, the 24-h pattern of activity bouts was disrupted by EtOH under all light intensities. Finally, replacement of chronic EtOH with water was used to examine withdrawal effects. Water controls had photic phase advances of 1.1 ± 0.3 h, while hamsters deprived of EtOH for 2–3 days showed enhanced shifts (2.1 ± 0.3 h; P < 0.05 vs. controls). Thus, in chronically drinking hamsters, brain EtOH levels are sufficient to inhibit photic phase resetting and disrupt circadian activity. Chronic EtOH did not impair photic entrainment; however, its replacement with water potentiated photic phase resetting.
Cyclophilin D gene ablation protects mice from ischemic renal injury
Authors: Devalaraja-Narashimha Kishor , Diener Alicia M. , Padanilam Babu J.
Published: June 2009

Increased oxidative stress and intracellular calcium levels and mitochondrial overloading of calcium during ischemic renal injury (IRI) favor mitochondrial membrane permeability transition pore (MPTP) opening and subsequent necrotic cell death. Cyclophilin D (CypD) is an essential component of MPTP, and recent findings implicate its role in necrotic, but not apoptotic, cell death. To evaluate the role of CypD following IRI, we tested the hypothesis that CypD gene ablation protects mice from IRI. Renal function as assessed by plasma levels of both creatinine and blood urea nitrogen was significantly reduced in CypD knockout (CypD−/−) mice compared with wild-type mice during the 5-day post-ischemia period. Erythrocyte trapping, tubular cell necrosis, tubular dilatation, and neutrophil infiltration were significantly decreased in CypD−/− mice. To define the mechanisms by which CypD deficiency protect the kidneys, an in vitro model of IRI was employed. Inhibition of CypD using Cyclosporin A in oxidant-injured cultured proximal tubular cells (PTC) prevented mitochondrial membrane depolarization, reduced LDH release, ATP depletion and necrotic cell death. Similarly, oxidant-injured CypD−/− PTC primary cultures were protected from cytotoxicity and necrosis. To conclude, CypD gene ablation offers both functional and morphological protection in mice following IRI by decreasing necrotic cell death possibly via inhibition of MPTP and ATP depletion.
Human immunodeficiency virus downregulates podocyteapoEexpression
Authors: Arora Shitij , Husain Mohammad , Kumar Dileep , Patni Hitesh , Pathak Shresh , Mehrotra Devi , Reddy Vivek Kathi , Reddy Lalit Rajeev , Salhan Divya , Yadav Anju , Mathieson Peter W. , Saleem Moin A. , Chander Praveen N. , Singhal Pravin C.
Published: June 2009

Apolipoprotein E ( apoE) has been demonstrated to play an important role in providing protection against mesangial cell injury. In the present study, we evaluated the role of apoE and its associated downstream effects in human immunodeficiency virus (HIV)-associated nephropathy (HIVAN). Control ( n = 6) and age- and sex-matched HIV-1 transgenic mice (Tg26, n = 6) were evaluated for their renal cortical expression of apoE. Renal tissue from Tg26 mice not only showed decreased apoE expression but also displayed downregulation of perlecan mRNA expression. In in vitro studies, conditionally immortalized human podocytes (CIHPs) were transduced with either NL4-3HIV (an HIV-1 construct lacking gag and pol, used for the development of Tg26 mouse model; NL4-3/CIHP) or empty vector (EV/CIHP); NL4-3/CIHPs and EV/CIHPs were studied for apoE mRNA expression. NL4-3/CIHPs showed reduction in apoE expression compared with EV/CIHPs. To evaluate the role of HIV-1 genes in the modulation of apoE expression, conditionally immortalized mouse podocytes (CIMPs) were transduced with individual HIV-1 gene constructs. Only nef-transduced CIMPs showed a decrease in apoE expression. To confirm this effect of nef in CIHPs, microarray analysis was performed in stable colonies of nef/CIHPs and EV/CIHPs. nef/CIHPs showed a 60% decrease in apoE and a 90% reduction in heparan sulfate mRNA expression. Moreover, nef transgenic mice showed a decrease in renal tissue expression of both apoE and perlecan. Both Tg26 and nef transgenic mice also showed areas of mesangial cell proliferation. These findings suggest that HIV-1-induced reduction in podocyte apoE expression and associated downregulation of podocyte perlecan might be contributing to mesangial cell (MC) phenotype in HIVAN.
Direction-Dependent Control of Balance During Walking and Standing
Authors: O'Connor Shawn M. , Kuo Arthur D.
Published: June 2009

Human walking has previously been described as “controlled falling.” Some computational models, however, suggest that gait may also have self-stabilizing aspects requiring little CNS control. The fore–aft component of walking may even be passively stable from step to step, whereas lateral motion may be unstable and require motor control for balance, as through active foot placement. If this is the case, walking humans might rely less on integrative sensory feedback, such as vision, for anteroposterior (AP) than for mediolateral (ML) balance. We tested whether healthy humans ( n = 10) exhibit such direction-dependent control, by applying low-frequency perturbations to the visual field (a projected virtual hallway) and measuring foot placement during treadmill walking. We found step variability to be nearly 10 times more sensitive to ML than to AP perturbations, as quantified by the increase in root-mean-square step variability per unit change in perturbation amplitude. This is not simply due to poorer physiological sensitivity of vision in the AP direction: similar perturbations applied to quiet standing produced reversed direction dependence, with an AP sensitivity 2.3-fold greater than that of ML. Tandem (heel-to-toe) standing yielded ML sensitivity threefold greater than that of AP, suggesting that the base of support influences the stability of standing. Postural balance nevertheless appears to require continuous, integrative motor control for balance in all directions. In contrast, walking balance requires step-by-step, integrative control for balance, but mainly in the lateral direction. In the fore–aft direction, balance may be maintained through an “uncontrolled,” yet passively stabilized, series of falls.
Effects of 17β-Estradiol on Responses of Viscerosomatic Convergent Thalamic Neurons in the Ovariectomized Female Rat
Authors: Reed William R. , Chadha Harpreet K. , Hubscher Charles H.
Published: June 2009

Ovarian hormones have been shown to exert multiple effects on CNS function and viscerosomatic convergent activity. Ovariectomized (OVX) female rats were used in the present study to examine the long-term effects of proestrus levels of 17β-estradiol (EB) delivered by a 60-day time-released subcutaneous pellet on the response properties of viscerosomatic convergent thalamic neurons. In addition, avoidance thresholds to mechanical stimulation for one of the convergent somatic territories, the trunk, was assessed using an electro–von Frey anesthesiometer before and at the end of the 6-wk post-OVX/implant period prior to the terminal electrophysiological experiments, which were done under urethane anesthesia. Rats implanted with an EB-containing pellet, relative to placebo controls, demonstrated 1) altered thalamic response frequencies and thresholds for cervix and vaginal but not colon stimulation; 2) some response variations for just the lateral group of thalamic subnuclei; and 3) altered thalamic response frequencies and thresholds for trunk stimulation. Thalamic response thresholds for trunk pressure in EB versus placebo rats were consistent with the avoidance thresholds obtained from the same groups. In addition, EB replacement affected visceral and somatic thresholds in opposite ways (i.e., reproductive-related structures were less sensitive to pressure, whereas somatic regions showed increased sensitivity). These results have obvious reproductive advantages (i.e., decreased reproductive organ sensitivity for copulation and increased trunk sensitivity for lordosis posturing), as well as possible clinical implications in women suffering from chronic pelvic pain syndromes and/or neuropathic pain.
Intrinsic Membrane Properties and Inhibitory Synaptic Input of Kenyon Cells as Mechanisms for Sparse Coding?
Authors: Demmer Heike , Kloppenburg Peter
Published: June 2009

The insect mushroom bodies (MBs) are multimodal signal processing centers and are essential for olfactory learning. Electrophysiological recordings from the MBs' principal component neurons, the Kenyon cells (KCs), showed a sparse representation of olfactory signals. It has been proposed that the intrinsic and synaptic properties of the KC circuitry combine to reduce the firing of action potentials and to generate relatively brief windows for synaptic integration in the KCs, thus causing them to operate as coincidence detectors. To better understand the ionic mechanisms that mediate the KC intrinsic firing properties, we used whole cell patch-clamp recordings from KCs in the adult, intact brain of Periplaneta americana to analyze voltage- and/or Ca2+-dependent inward ( ICa, INa) and outward currents [ IA, IK(V), IK,ST, IO(Ca)]. In general the currents had properties similar to those of currents in other insect neurons. Certain functional parameters of ICaand IO(Ca), however, had unusually high values, allowing them to assist sparse coding. ICahad a low-activation threshold and a very high current density compared with those of ICain other insect neurons. Together these parameters make ICasuitable for boosting and sharpening the excitatory postsynaptic potentials as reported in previous studies. IO(Ca)also had a large current density and a very depolarized activation threshold. In combination, the large ICaand IO(Ca)are likely to mediate the strong spike frequency adaptation. These intrinsic properties of the KCs are likely to be supported by their tonic, inhibitory synaptic input, which was revealed by specific GABA antagonists and which contributes significantly to the hyperpolarized membrane potential at rest.
TNFα Mechanically Sensitizes Masseter Muscle Afferent Fibers of Male Rats
Authors: Hakim Akhlaq W. , Dong Xu-Dong , Svensson Peter , Kumar Ujendra , Cairns Brian E.
Published: June 2009

Behavioral evidence in rats indicates that injection of tumor necrosis factor alpha (TNFα) into skeletal muscle results in a prolonged mechanical sensitization without gross inflammation. To investigate whether a peripheral mechanism could underlie this effect, in the present study, TNFα (1 or 0.1 μg) was injected into the rat masseter muscle to assess its effect on the excitability and mechanical threshold (MT) of muscle nociceptors as well as on inflammation. Expression of TNFR1 (P55 receptors) and TNFR2 (P75 receptors) by the masseter muscle and trigeminal ganglion neurons that innervate that muscle was determined by Western blot and immunohistochemistry, respectively. The Evans blue dye technique was used at the end of the TNFα experiments to assess for plasma protein extravasation. In subsequent experiments to confirm the involvement of receptor activation in TNFα-induced effects, P55 or P75 receptor antibody was co-injected with TNFα. Intramuscular injection of 1 μg TNFα did not excite nociceptors but did significantly decrease MT compared with vehicle control. There was no evidence of gross inflammation 3 h after injection of TNFα. Co-injection of TNFα with P55 or P75 receptor antibodies attenuated TNFα-induced mechanical sensitization. P55 and P75 receptors were expressed by 29 and 62% of masseter nociceptors, respectively. These findings indicate that TNFα induces mechanical sensitization of masseter nociceptors that is mediated through activation of peripheral P55 and P75 receptors. These results support the hypothesis that a peripheral receptor mechanism could contribute to TNFα-induced noninflammatory mechanical sensitization of skeletal muscle previously reported in behaving rats.
Neural Activity in the Human Brain Signals Logical Rule Identification
Authors: Tachibana Kaori , Suzuki Kyoko , Mori Etsuro , Miura Naoki , Kawashima Ryuta , Horie Kaoru , Sato Shigeru , Tanji Jun , Mushiake Hajime
Published: June 2009

To select an appropriate action, we conform to a behavioral rule determined uniquely in each behavioral context. If the rule is not predetermined and must be discovered, we often test hypotheses concerning rules by applying one candidate rule after another. The neural mechanisms underlying such rule identification are still unknown. To explore which brain areas are involved in the process of logical rule identification and to determine whether such areas differ from those taking part in implementing the rule to find a suitable action, we measured brain activation using functional magnetic resonance imaging while subjects performed a rule-identification task. The subjects were required to select a red or blue square on a screen based on either a “sequence rule” or a “probability rule.” Positive or negative feedback to the subject's choice led the subject to identify the correct rule. We found that the posterior medial frontal cortex (pMFC), caudate nucleus, fusiform gyrus, and middle temporal cortex exhibited significant activation during the period when subjects underwent the hypothesis testing. Among these brain areas, the pMFC and caudate nucleus were also activated in response to the critical feedback signals selectively during the trials when the subjects identified a rule. Furthermore, we found a significant enhancement in effective connectivity between the active regions in the pMFC and caudate regions.
Differential Effects of Cognitive Demand on Human Cortical Activation Associated With Vibrotactile Stimulation
Authors: Albanese M.-C. , Duerden E. G. , Bohotin V. , Rainville P. , Duncan G. H.
Published: June 2009

This event-related functional MRI study examines the neural correlates of vibrotactile sensation within the context of different psychophysical demands. Nine subjects received vibrotactile stimuli on the right volar forearm during detection, localization, and passive tasks. In the detection task, subjects indicated the offset (end) of each stimulus by pressing a response key with their left hand. In the localization task, subjects identified the location of the stimulus (“distal?” or “proximal?”) by pressing the appropriate response key 4 s after the end of the stimulus. In the passive task, subjects received the same vibrotactile stimuli, but no response was required. Analysis of stimulus-evoked activity compared with the resting baseline period revealed significant bilateral secondary somatosensory cortex activation for all three tasks. However, only in the offset-detection and localization tasks was stimulus-evoked activation observed in other expected areas of tactile processing, such as contralateral primary somatosensory cortex neighboring the posterior parietal cortex (SI/PPC) and in bilateral anterior insular cortex (aIC). During the localization task, we identified vibrotactile-evoked activation in the right aIC, which was maintained after the termination of the stimulus. Results suggest that vibrotactile-related activation within SI/PPC and aIC is enhanced by the increased levels of attention and cognitive demands required by the detection and localization tasks. Activation of aIC not only during vibrotactile stimulation, but also during the poststimulus delay in the localization trials, is consistent with the growing literature linking this area with the perception and short-term memory of tactile information.
Regulation of the Benzamil-Insensitive Salt Taste Receptor by Intracellular Ca2+, Protein Kinase C, and Calcineurin
Authors: Lyall Vijay , Phan Tam-Hao T. , Mummalaneni Shobha , Melone Pamela , Mahavadi Sunila , Murthy Karnam S. , DeSimone John A.
Published: June 2009

The regulation of the benzamil (Bz)-insensitive salt taste receptor was investigated by intracellular Ca2+ ([Ca2+]i), protein kinase C (PKC), and the Ca2+-dependent serine-threonine phosphatase, calcineurin (PP2B), by monitoring chorda tympani taste nerve responses to 0.1 M NaCl solutions containing Bz (5 × 10−6 M) and resiniferatoxin (RTX; 0–10 × 10−6 M) in Sprague–Dawley rats and in wild-type (WT) and transient receptor potential vanilloid-1 knockout (TRPV1 KO) mice. In rats and WT mice, RTX increased the NaCl + Bz chorda tympani responses between 0.25 × 10−6 and 1 × 10−6 M and inhibited the responses above 1 × 10−6 M. Decreasing taste receptor cell (TRC) [Ca2+]i with BAPTA loading, activation of PKC with 4α-phorbol-12,13-didecanoate (PMA), or inhibition of PP2B by cyclosporin A or FK-506, enhanced the magnitude of the Bz-insensitive NaCl chorda tympani responses in the presence of RTX and either minimized or completely eliminated the decrease in the chorda tympani response >1 × 10−6 M RTX. In contrast, increasing TRC [Ca2+]i with ionomycin inhibited Bz-insensitive NaCl chorda tympani responses in the presence of RTX. No effect of the cited modulators was observed on the chorda tympani responses in WT mice and rats in the presence of TRPV1 blocker SB-366791 (1 × 10−6 M) or in TRPV1 KO mice. 32P-labeling demonstrated direct phosphorylation of TRPV1 or TRPV1t in anterior lingual epithelium by PMA, cyclosporin A, or FK-506. PMA also enhanced the RTX-sensitive unilateral apical Na+ flux in polarized fungiform TRC in vitro. We conclude that TRPV1 or its variant TRPV1t is phosphorylated and dephosphorylated by PKC and PP2B, respectively, and either sensitizes or desensitizes the Bz-insensitive NaCl chorda tympani responses to RTX stimulation.
Aggressive Angiomyxoma of the Scrotum Mimicking Huge Hydrocele: Case Report and Literature Review
Authors: Morag Roy , Fridman Eduard , Mor Yoram
Published: June 2009

Aggressive Angiomyxoma (AAM) is a rare mesenchymal benign myxoid tumor of the pelvis and perineum which occurs almost exclusively in adult females. We are presenting a case of 64 year old male patient with a slowly growing scrotal swelling which has been regarded as hydrocele for 2 years. The patient was referred to scrotal exploration. At surgery a huge mass adjacent to the bulbar urethra was found, not involving the testicles. The morphological picture and the special stains were compatible with aggressive angiomyxoma of the scrotum and peritoneum.
Synchronization of Discrete‐Time Chaotic Systems in Bandlimited Channels
Authors: Eisencraft Marcio , Fanganiello Renato D. , Baccala Luiz A.
Published: June 2009

Over the last couple of decades, many methods for synchronizing chaotic systems have been proposed with communications applications in view. Yet their performance has proved disappointing in face of the nonideal character of usual channels linking transmitter and receiver, that is, due to both noise and signal propagation distortion. Here we consider a discrete‐time master‐slave system that synchronizes despite channel bandwidth limitations and an allied communication system. Synchronization is achieved introducing a digital filter that limits the spectral content of the feedback loop responsible for producing the transmitted signal.
Small Scale Spatial Variability of Apparent Electrical Conductivity within a Paddy Field
Authors: Aimrun W. , Amin M. S. M. , Ezrin M. H.
Published: June 2009

Quick variability description is an important component for zone management practices. Precision farming requires topping up of only the nutrients that are lacking in the soil to attain the highest yield with the least input. The apparent soil electrical conductivity (ECa) sensor is a useful tool in mapping to identify areas of contrasting soil properties. In nonsaline soils,ECais a substitute measurement for soil texture. It is directly related to both water holding capacity and Cation Exchange Capacity (CEC), which are key ingredients of productivity. This sensor measures theECaacross a field quickly and gives detailed soil features (one-second interval) with few operators. Hence, a dense sampling is possible and therefore a high-resolutionECamap can be produced. This study aims to characterize the variability of soilECawithin a Malaysian paddy field with respect to the spatial and seasonal variability. The study was conducted at Block C, Sawah Sempadan, Selangor, Malaysia, for three continuous seasons. SoilECawas collected after harvesting period. The results showed that deepECavisualized the pattern of the former river routes clearly as continuous lines (about 45 m width) at the northern and central regions of the study area. This exploration has shown different maps with higher contrast as compared to the existing soil series map for the study area. Seasonal variability test showed that theECathat was acquired during rainy season (collected after harvest in December to January) has the highest value as compared to another season.
SGRs and AXPs: Evidence for Delayed Amplification of Magnetic Field after Neutron Star Formation?
Authors: Leahy Denis , Ouyed Rachid
Published: June 2009

We present new analysis of the birth rate of AXPs and SGRS and their associated SNRs. Using
Kolmogorov‐Smirnov statistics together with parametric fits based on a robust estimator, we find a birth rate of ~1/(1000 years) for AXPs/SGRs and their associated SNRs. These high rates suggest that all massive stars (greater
than ~(23–32)M⊙) give rise to remnants with magnetar‐like fields. Observations indicate a limited fraction of
high magnetic fields in these progenitors; thus our study is suggestive of magnetic field amplification. Dynamo
mechanisms during the birth of the neutron stars require spin rates much faster than either observations or theory
indicate. We propose that massive stars produce neutron stars with normal (~1012 G) magnetic fields, which are
then amplified to 1014‐1015 G after a delay of hundreds of years. The amplification is speculated to be a consequence
of color ferromagnetism and to occur with a delay after the neutron star core reaches quark deconfinement density
(i.e., the quark‐nova scenario). The delayed amplification allows one to interpret simultaneously the high birth
rate and high magnetic fields of AXPs/SGRs and their link to massive stars.
Investigation of CMOS Varactors for High‐GHz‐Range Applications
Authors: Li Ming , Amaya Rony E. , Harrison Robert G. , Tarr N. Garry
Published: June 2009

This paper explores a variety of different CMOS varactor structures for RF and MMICs. A typical 0.18 μm CMOS foundry process was used as the study platform. The varactors′ capacitance‐voltage characteristics and cutoff frequencies have been examined up to 55 GHz. The primary aim of this work is to design varactors that can improve nonlinear‐transmission‐line (NLTL) pulse‐compression circuits. The results should also be valuable for other applications up to millimeter wavelengths.
Rapid Diagnosis of Intestinal Parasitic Protozoa, with a Focus onEntamoeba histolytica
Authors: Singh Anjana , Houpt Eric , Petri William A.
Published: June 2009

Entamoeba histolyticais an invasive intestinal pathogenic parasitic protozoan that causes amebiasis. It must be distinguished fromEntamoeba disparandE. moshkovskii, nonpathogenic commensal parasites of the human gut lumen that are morphologically identical toE. histolytica. Detection of specificE. histolyticaantigens in stools is a fast, sensitive technique that should be considered as the method of choice. Stool real-time PCR is a highly sensitive and specific technique but its high cost make it unsuitable for use in endemic areas where there are economic constraints. Serology is an important component of the diagnosis of intestinal and especially extraintestinal amebiasis as it is a sensitive test that complements the detection of the parasite antigens or DNA. Circulating Gal/GalNac lectin antigens can be detected in the serum of patients with untreated amoebic liver abscess. On the horizon are multiplex real-time PCR assays which permit the identification of multiple enteropathogens with high sensitivity and specificity.
A Reconfigurable and Biologically Inspired Paradigm for Computation Using Network‐On‐Chip and Spiking Neural Networks
Authors: Harkin Jim , Morgan Fearghal , McDaid Liam , Hall Steve , McGinley Brian , Cawley Seamus
Published: June 2009

FPGA devices have emerged as a popular platform for the rapid prototyping of biological Spiking Neural Networks (SNNs) applications, offering the key requirement of reconfigurability. However, FPGAs do not efficiently realise the biologically plausible neuron and synaptic models of SNNs, and current FPGA routing structures cannot accommodate the high levels of interneuron connectivity inherent in complex SNNs. This paper highlights and discusses the current challenges of implementing scalable SNNs on reconfigurable FPGAs. The paper proposes a novel field programmable neural network architecture (EMBRACE), incorporating low‐power analogue spiking neurons, interconnected using a Network‐on‐Chip architecture. Results on the evaluation of the EMBRACE architecture using the XOR benchmark problem are presented, and the performance of the architecture is discussed. The paper also discusses the adaptability of the EMBRACE architecture in supporting fault tolerant computing.
Prehospital Use of the Intubating Laryngeal Mask Airway in Patients with Severe Polytrauma: A Case Series
Authors: Mason Andrew M.
Published: June 2009

A case series of five patients is described demonstrating the utility of the intubating laryngeal mask airway in the prehospital setting, both as a primary airway rescue device and as a bridge to tracheal intubation. All patients were hypoxaemic, had sustained severe polytrauma and were trapped in their vehicles following road traffic collisions. A probability of survival study showed better-than-predicted outcomes for the group as a whole.
Nanosized TiO2 Photocatalyst Powder via Sol‐Gel Method: Effect of Hydrolysis Degree on Powder Properties
Authors: Hafizah Nor , Sopyan Iis
Published: June 2009

Nanosized TiO2 powder was synthesized via sol‐gel method using titanium tetraisopoxide (TPT) as the precursor. Mol ratios of water to TPT were varied from 1 (Powder A), 2 (Powder B), 3 (Powder C), and 4 (Powder D) to evaluate effect of hydrolysis degree. TG/DTA curves showed that amorphous phase turned to anatase crystal structure at ca. 415, 337, 310, and 339∘C for Powders A, B, C, and D, respectively. XRD analysis showed that all the synthesized TiO2 powders were 100% in anatase form with Powders B and C showing considerably higher crystallinities. The powders obtained at lower water to TPT mol ratios were spherical in shape and they became bar‐like shapes higher mol ratios. The lower hydrolysis degree led to higher surface area of the Powder A (24.8 m2/g) compared to Powder B (14.6 m2/g). From phenol photocatalytic measurement, Powder B was the most efficient attributed to its higher crystallinity.
An Analysis of Eye Scanpath Entropy in a Progressively Forming Virtual Environment
Authors: Jordan Joel , Slater Mel
Published: June 2009

A sign of presence in virtual environments is that people respond to situations and events as if they were real, where response may be considered at many different levels, ranging from unconscious physiological responses through to overt behavior, emotions, and thoughts. In this paper we consider two responses that gave different indications of the onset of presence in a gradually forming environment. Two aspects of the response of people to an immersive virtual environment were recorded: their eye scanpath, and their skin conductance response (SCR). The scenario was formed over a period of 2 min, by introducing an increasing number of its polygons in random order in a head-tracked head-mounted display. For one group of experimental participants (n = 8) the environment formed into one in which they found themselves standing on top of a 3 m high column. For a second group of participants (n = 6) the environment was otherwise the same except that the column was only 1 cm high, so that they would be standing at normal ground level. For a third group of participants (n = 14) the polygons never formed into a meaningful environment. The participants who stood on top of the tall column exhibited a significant decrease in entropy of the eye scanpath and an increase in the number of SCR by 99 s into the scenario, at a time when only 65% of the polygons had been displayed. The ground level participants exhibited a similar decrease in scanpath entropy, but not the increase in SCR. The random scenario grouping did not exhibit this decrease in eye scanpath entropy. A drop in scanpath entropy indicates that the environment had cohered into a meaningful perception. An increase in the rate of SCR indicates the perception of an aversive stimulus. These results suggest that on these two dimensions (scanpath entropy and rate of SCR) participants were responding realistically to the scenario shown in the virtual environment. In addition, the response occurred well before the entire scenario had been displayed, suggesting that once a set of minimal cues exists within a scenario, it is enough to form a meaningful perception. Moreover, at the level of the sympathetic nervous system, the participants who were standing on top of the column exhibited arousal as if their experience might be real. This is an important practical aspect of the concept of presence.
Aristotle on Soul and Soul-'Parts' in Semen (GA 2.1, 735a4-22)
Authors: Bos Abraham
Published: June 2009

Aristotle,

Generation of Animals

2.1, 735a4-22 speaks about semen and soul. The passage speaks about 'the soul' and 'the parts'. Against all current interpretations it is argued that Aristotle means 'the soul in its entirety' and 'the parts

of the soul

'. It is proposed that the Greek text edited by Drossaart Lulofs in 735a22 be corrected by accepting the reading of ms Z.
Gaia Gets to Know Herself: Proclus on the World's Self-Perception
Authors: Baltzly Dirk
Published: June 2009

Proclus' interpretation of the Timaeus confronts the question of whether the living being that is the Platonic cosmos perceives itself. Since sense perception is a mixed blessing in the Platonic tradition, Proclus solves this problem by differentiating different gradations of perception. The cosmos has only the highest kind. This paper contrasts Proclus' account of the world's perception of itself with James Lovelock's notion that the planet Earth, or Gaia, is aware of things going on within itself. This contrast illuminates several key differences between contemporary theories of perception and the neoplatonic world view. In particular, it argues that the neoplatonists had a radically different view of these matters because they assigned the property of truth not only to representations, but to objects as well.
Knowing by Likeness in Empedocles
Authors: Kamtekar Rachana
Published: June 2009

Contrary to the Aristotelian interpretation of Empedocles' views about cognition, according to which all cognition, like perception, is due to the compositional likeness between subject and object of cognition, this paper argues that when Empedocles says that we know one thing 'by' another (e.g. earth by earth or love by love), he is characterizing analogical reasoning, an intellectual activity quite different from perception (which is explained by the fit between effluences and pores). The paper also explores the idea that strife and love describe, in addition to physical separation and composition, the mental activities of analyzing and composing.
Towards a Theology of Place in the South African Context: Some Reflections from the Perspective of Ecotheology
Authors: Conradie Ernst
Published: June 2009

A theology of place has deep roots within the Jewish-Christian tradition. However, a theology of place has become obscured as a result of various trends in modernity. It has re-emerged through a number of theological strands over the past few decades, including various branches of ecotheology. Indeed, it would not be inappropriate to identify a widespread “spatial turn” in current intellectual discourse, including Christian theology. Such developments are specifically important within the South African context where, in the theme of the 2008 annual meeting of the Theological Society of South Africa, “grace, race and space” have become deeply entangled with each other.
Re-enchanting a Disenchanted Universe – Post Modern Projects in Theologies of Space
Authors: Balcomb Anthony
Published: June 2009

'Disenchantment' was an expression coined by Max Weber to describe a process whereby the world was rid of all spiritual reality and subjected to the power of the calculating and rational human mind. An enchanted universe was one in which space was presenced with spiritual agency, where things were subjects, not objects, and in which an epistemology of engagement, not disengagement, operated. Disenchantment involved, amongst other things, the emptying of space, the objectification of being, and the linearizing of time. Christian theology from the seventeenth century became associated with a disenchanted, modernizing agenda through early Christian scientists such as Bacon, Newton, and Descartes. While modernity has brought unprecedented levels of supremacy over nature the association of Christian theology with the modern agenda of disenchantment has been questioned in the postmodern context. Theologies of place and space are now being sought that take seriously an agenda that places God and spirituality back in the world and not beyond the world, that emphasizes an organic and not a mechanistic universe, and that resuscitates the notion of agency in the world.
Die ,,Wissenschaft des Judentums“ und die Anfänge der kritischen Koranforschung Perspektiven einer modernen Koranhermeneutik
Authors: Hartwig Dirk
Published: June 2009

This article traces the beginnings of critical Qur'anic Studies to the nineteenth-century scholars of the so-called Science of Judaism school (Wissenschaft des Judentums). Until the 1930s, when the rise of the Nazis violently suppressed Jewish scholarly activities in Germany and elsewhere, generations of scholars such as Abraham Geiger, who is better known as an early leader of the Jewish Reform Movement, dedicated their lives to the study of the Qur'an and established a new discipline: Qur'anic Studies. These scholars, in many ways pioneers in their fields, authored a series of significant studies that contextualized the foundational documents of Islam with Rabbinic literature and were the first to undertake an unbiased study of early Islamic writings.