bluuebunny/crossref_metadata_2025 huggingface dataset:
The UL12 Protein of Herpes Simplex Virus 1 Is Regulated by Tyrosine Phosphorylation
Authors: Fujii Hikaru , Kato Akihisa , Mugitani Michio , Kashima Yukie , Oyama Masaaki , Kozuka-Hata Hiroko , Arii Jun , Kawaguchi Yasushi
Published: July 2014

The herpes simplex virus 1 (HSV-1) UL12 protein (pUL12) is a nuclease that is critical for viral replication
in vitro
and neurovirulence
in vivo
. In this study, mass spectrometric analysis of pUL12 and phosphate-affinity SDS-polyacrylamide gel electrophoresis analysis identified tyrosine at pUL12 residue 371 (Tyr-371) as a pUL12 phosphorylation site: Tyr-371 is conserved in pUL12 homologs in herpesviruses in all
Herpesviridae
subfamilies. Replacement of Tyr-371 with phenylalanine (Y371F) in pUL12 (i) abolished its exonuclease activity in HSV-1-infected Vero, HEL, and A549 cells, (ii) reduced viral replication, cell-cell spread, and pUL12 expression in infected cells in a cell type-dependent manner, (iii) led to aberrant subcellular localization of pUL12 in infected cells in a cell type-dependent manner, and (iv) reduced HSV-1 neurovirulence in mice. The effects of the pUL12 Y371F mutation in cell cultures and mice were similar to those of a nuclease-dead double mutation in pUL12, although the Y371F mutation reduced viral replication severalfold more than the nuclease-dead double mutation in a cell type- and multiplicity-of-infection-dependent manner. Replacement of Tyr-371 with glutamic acid, which mimics constitutive phosphorylation, restored the wild-type phenotype in cell cultures and mice. These results suggested that phosphorylation of pUL12 Tyr-371 was essential for pUL12 to express its nuclease activity in HSV-1-infected cells and that this phosphorylation promoted viral replication and cell-cell spread in cell cultures and neurovirulence in mice mainly by upregulating pUL12 nuclease activity and, in part, by regulating the subcellular localization and expression of pUL12 in HSV-1-infected cells.

IMPORTANCE
Herpesviruses encode a considerable number of enzymes for their replication. Like cellular enzymes, the viral enzymes need to be properly regulated in infected cells. Although the functional aspects of herpesvirus enzymes have gradually been clarified, information on how most of these enzymes are regulated in infected cells is lacking. In the present study, we report that the enzymatic activity of the herpes simplex virus 1 alkaline nuclease pUL12 was regulated by phosphorylation of pUL12 Tyr-371 in infected cells and that this phosphorylation promoted viral replication and cell-cell spread in cell cultures and neurovirulence in mice, mainly by upregulating pUL12 nuclease activity. Interestingly, pUL12 and tyrosine at pUL12 residue 371 appeared to be conserved in all herpesviruses in the family
Herpesviridae
, raising the possibility that the herpesvirus pUL12 homologs may also be regulated by phosphorylation of the conserved tyrosine residue.
Genomic Diversity of Epstein-Barr Virus Genomes Isolated from Primary Nasopharyngeal Carcinoma Biopsy Samples
Authors: Kwok H. , Wu C. W. , Palser A. L. , Kellam P. , Sham P. C. , Kwong D. L. W. , Chiang A. K. S.
Published: July 2014

Undifferentiated nasopharyngeal carcinoma (NPC) has a 100% association with Epstein-Barr virus (EBV). However, only three EBV genomes isolated from NPC patients have been sequenced to date, and the role of EBV genomic variations in the pathogenesis of NPC is unclear. We sought to obtain the sequences of EBV genomes in multiple NPC biopsy specimens in the same geographic location in order to reveal their sequence diversity. Three published EBV (B95-8, C666-1, and HKNPC1) genomes were first resequenced using the sequencing workflow of target enrichment of EBV DNA by hybridization, followed by next-generation sequencing,
de novo
assembly, and joining of contigs by Sanger sequencing. The sequences of eight NPC biopsy specimen-derived EBV (NPC-EBV) genomes, designated HKNPC2 to HKNPC9, were then determined. They harbored 1,736 variations in total, including 1,601 substitutions, 64 insertions, and 71 deletions, compared to the reference EBV. Furthermore, genes encoding latent, early lytic, and tegument proteins and glycoproteins were found to contain nonsynonymous mutations of potential biological significance. Phylogenetic analysis showed that the HKNPC6 and -7 genomes, which were isolated from tumor biopsy specimens of advanced metastatic NPC cases, were distinct from the other six NPC-EBV genomes, suggesting the presence of at least two parental lineages of EBV among the NPC-EBV genomes. In conclusion, much greater sequence diversity among EBV isolates derived from NPC biopsy specimens is demonstrated on a whole-genome level through a complete sequencing workflow. Large-scale sequencing and comparison of EBV genomes isolated from NPC and normal subjects should be performed to assess whether EBV genomic variations contribute to NPC pathogenesis.

IMPORTANCE
This study established a sequencing workflow from EBV DNA capture and sequencing to
de novo
assembly and contig joining. We reported eight newly sequenced EBV genomes isolated from primary NPC biopsy specimens and revealed the sequence diversity on a whole-genome level among these EBV isolates. At least two lineages of EBV strains are observed, and recombination among these lineages is inferred. Our study has demonstrated the value of, and provided a platform for, genome sequencing of EBV.
A Non-SUMOylated Tax Protein Is Still Functional for NF-κB Pathway Activation
Authors: Pène Sabrina , Waast Laetitia , Bonnet Amandine , Bénit Laurence , Pique Claudine
Published: July 2014

Whether NF-κB promoter transactivation by the human T-cell leukemia virus type 1 (HTLV-1) Tax protein requires Tax SUMOylation is still a matter of debate. In this study, we revisited the role of Tax SUMOylation using a strategy based on the targeting of Ubc9, the unique E2 SUMO-conjugating enzyme. We show that either a catalytically inactive form of Ubc9 (Ubc9-C93S) or Ubc9 small interfering RNA (siRNA) dramatically reduces Tax conjugation to endogenous SUMO-1 or SUMO-2/3, demonstrating that as expected, Tax SUMOylation is under the control of the catalytic activity of Ubc9. We further report that a non-SUMOylated Tax protein produced in 293T cells is still able to activate either a transfected or an integrated NF-κB reporter promoter and to induce expression of an NF-κB-regulated endogenous gene. Importantly, blocking Ubc9 activity in T cells also results in the production of a non-SUMOylated Tax that is still fully functional for the activation of a NF-κB promoter. These results provide the definitive evidence that Tax SUMOylation is not required for NF-κB-driven gene induction.

IMPORTANCE
Human T-cell leukemia virus type 1 is able to transform CD4
+
T lymphocytes. The viral oncoprotein Tax plays a key role in this process by promoting cell proliferation and survival, mainly through permanent activation of the NF-κB pathway. Elucidating the molecular mechanisms involved in NF-κB pathway activation by Tax is therefore a key issue to understand HTLV-1-mediated transformation. Tax SUMOylation was initially proposed to be critical for Tax-induced NF-κB promoter activation, which was challenged by our later observation that a low-level-SUMOylated Tax mutant was still functional for activation of NF-κB promoters. To clarify the role of Tax SUMOylation, we set up a new approach based on the inhibition of the SUMOylation machinery in Tax-expressing cells. We show that blocking the SUMO-conjugating enzyme Ubc9 abolishes Tax SUMOylation and that a non-SUMOylated Tax still activates NF-κB promoters in either adherent cells or T cells.
A Feasibility Study to Examine the Role of Acupuncture to Reduce Symptoms of Lymphoedema after Breast Cancer: A Randomised Controlled Trial
Authors: Smith Caroline A , Pirotta Marie , Kilbreath Sharon
Published: July 2014

Objective

To determine the feasibility, acceptability and safety of using acupuncture to treat arm lymphoedema in women following treatment for breast cancer.

Methods

We conducted a randomised controlled trial of acupuncture compared with treatment as usual. Twenty women with stable unilateral intransient lymphoedema present for at least 6 months were recruited from Sydney, Australia. The women received 12 acupuncture treatments administered to body and arm points on the non-lymphoedematous limb over 8 weeks, twice weekly for 4 weeks then once weekly for 4 weeks. Outcome measures included an assessment of interest to participate in the trial, identification of successful recruitment strategies, the appropriateness of eligibility criteria and compliance with treatment attendance. Clinical outcomes were assessed at baseline and 8 weeks and included extracellular fluid, lymphoedema symptoms, well-being and safety.

Results

Acupuncture was an acceptable intervention in women with upper limb lymphoedema. Compliance with the treatment protocol was high, with nine women completing all 12 treatments. Outcome forms were completed by 17 women at 8 weeks. No major adverse occurrences, as defined by the study protocol, were reported from the acupuncture group although one woman found the needling uncomfortable, and no study participant experienced an increase in swelling of >10%. There was no change in extracellular fluid or any patient-reported outcome measurement.

Conclusions

Lymphoedema is a persistent symptom experienced by women recovering from breast cancer. Our study suggests that acupuncture may stabilise symptoms and no major safety concerns were identified, so further research is needed.

Trial Registration Number

Australian New Zealand Clinical Trials Registry, http://www.anzctr.org.au ACTRN12612000607875.
Recurrent pneumonia due to endobronchial foreign body
Authors: Madsen Anne , Madsen Poul Henning
Published: July 2014

Endobronchial foreign body is a well-known but rare diagnosis when encountering adult patients with unexplained recurring pneumonias. Often, the symptoms are subtle and can be mistaken for other more common conditions. A high degree of clinical suspicion is essential in diagnosing these patients. In the presented case of recurrent pneumonia and prolonged coughing, an endobronchial foreign body was revealed several months after the aspiration when a thorough medical history was taken. An almond was found by flexible bronchoscopy and removed by emergency rigid bronchoscopy; the symptoms later resolved. We discuss the importance of taking a thorough medical history, which in many cases is the clue to correct diagnosis and treatment. In addition, we discuss the diagnostic workup and therapy in cases of endobronchial foreign bodies.
A case of disseminated recurrent retroperitoneal plasmacytoma with left obstructive hydronephrosis
Authors: Mainali Naba Raj , Jalota Leena , Pathak Ranjan , Jain Shashank
Published: July 2014

Retroperitoneal extramedullary plasmacytoma (EMP) is a rare condition that often poses a diagnostic challenge. This is mainly due to its unusual location and non-specific symptoms especially in its early stages. Retroperitoneal plasmacytoma with renal involvement is an extremely rare entity and to date, less than 25 cases have been reported in the literature. We describe a case of a 65-year-old woman with primary retroperitoneal plasmacytoma, confirmed by ultrasound-guided biopsy and histopathological examination, with unilateral left obstructive hydronephrosis and metastasis to the lungs. Our patient was started on chemotherapy to which she did not respond. Subsequently, she resorted to palliative measures. Our case highlights key aspects of clinical presentation, diagnosis and treatment options available for management of retroperitoneal plasmacytoma.
Understanding how self-management interventions work for disadvantaged populations living with chronic conditions: protocol for a realist synthesis
Authors: Mills Susan L , Pumarino Javiera , Clark Nancy , Carroll Simon , Dennis Sarah , Koehn Sharon , Yu Tricia , Davis Connie , Fong Maylene
Published: July 2014

Introduction

Self-management programmes are complex interventions aimed at improving the way individuals self-manage chronic conditions, but there are questions about the overall impact of these programmes on disadvantaged populations, in terms of their capacity to engage with and receive the benefits from these initiatives. Given the increased resources being directed towards self-management initiatives, clinicians and policy makers need knowledge on how self-management interventions work for these populations. Most systematic reviews of self-management interventions do not consider the complex interactions between implementation contexts, intervention strategies, and mechanisms that influence how self-management interventions work in real life for disadvantaged groups.

Methods

To address the need for better understanding of these mechanisms and to create context-relevant knowledge, we are conducting a realist synthesis of evidence on self-management interventions for disadvantaged populations living with chronic conditions. The primary research question is: What are the key mechanisms operating in chronic condition self-management interventions among disadvantaged populations? In this protocol, we outline the steps we will take to identify the programme theory for self-management interventions and candidate middle-range theories; to search for evidence in academic and grey literature; to appraise and extract the collected evidence; to synthesise and interpret the findings to generate key context-mechanism-outcome configurations and to disseminate results to relevant stakeholder and to peer-review publications.

Dissemination

Understandings of how chronic conditions self-management interventions work among disadvantaged populations is essential knowledge for clinicians and other decision makers who need to know which programmes they should implement for which groups. Results will also benefit medical researchers who want to direct effort towards current gaps in knowledge in order to advance the self-management field. In addition, the study will make a contribution to the evolving body of knowledge on the realist synthesis method and, in particular, to its application to behaviour change interventions for disadvantaged populations.
Alfaxalone as an induction agent for anaesthesia in terrapins and tortoises
Authors: Knotek Z.
Published: July 2014

The aim of this study was to evaluate short‐term intravenous anaesthesia with alfaxalone in chelonians. In the first part of the study, alfaxalone at a dose rate of 5 mg/kg was administered intravenously to 10 adult female red‐eared terrapins (Trachemys scripta elegans) following 24 hours of fasting. The induction time, tracheal tube insertion time, surgical plane of anaesthesia interval, and full recovery time were recorded. The head, neck and leg withdrawal reflex was lost within 21.09±8.07 seconds. The mean tracheal tube insertion time, the time of surgical plane of anaesthesia and full recovery time were 27.50±12.96 seconds, 26.40±4.72 minutes and 33.70±4.76 minutes, respectively. In the second part of the study, 50 chelonians (20 red‐eared terrapins, 10 Hermann's tortoises, eight spur‐thighed tortoises, six marginated tortoises and six Russian tortoises) were treated intravenously with 5 mg/kg alfaxalone after administration of 1 mg/kg meloxicam and 2 mg/kg butorphanol intramuscularly. The head, neck and leg withdrawal reflex was lost within 21.52±6.57 seconds, the endotracheal tube could be inserted within 25.76±8.24 seconds, and the time to deep pain sensation loss was 29.46±9.67 seconds. Intravenous use of alfaxalone proved to be a suitable method of induction for inhalation anaesthesia in terrapins and tortoises.
EXTRACTION OF NEURAL CONTROL COMMANDS USING MYOELECTRIC PATTERN RECOGNITION: A NOVEL APPLICATION IN ADULTS WITH CEREBRAL PALSY
Authors: LIU JIE , LI XIAOYAN , MARCINIAK CHRISTINA , RYMER WILLIAM ZEV , ZHOU PING
Published: July 2014

This study investigates an electromyogram (EMG)-based neural interface toward hand rehabilitation for patients with cerebral palsy (CP). Forty-eight channels of surface EMG signals were recorded from the forearm of eight adult subjects with CP, while they tried to perform six different hand grasp patterns. A series of myoelectric pattern recognition analyses were performed to identify the movement intention of each subject with different EMG feature sets and classifiers. Our results indicate that across all subjects high accuracies (average overall classification accuracy > 98%) can be achieved in classification of six different hand movements, suggesting that there is substantial motor control information contained in paretic muscles of the CP subjects. Furthermore, with a feature selection analysis, it was found that a small number of ranked EMG features can maintain high classification accuracies comparable to those obtained using all the EMG features (average overall classification accuracy > 96% with 16 selected EMG features). The findings of the study suggest that myoelectric pattern recognition may be a useful control strategy for promoting hand rehabilitation in CP patients.
RETRIEVAL OF NOISY FINGERPRINT PATTERNS USING METRIC ATTRACTOR NETWORKS
Authors: GONZÁLEZ MARIO , DOMINGUEZ DAVID , RODRÍGUEZ FRANCISCO B. , SÁNCHEZ ÁNGEL
Published: July 2014

This work experimentally analyzes the learning and retrieval capabilities of the diluted metric attractor neural network when applied to collections of fingerprint images. The computational cost of the network decreases with the dilution, so we can increase the region of interest to cover almost the complete fingerprint. The network retrieval was successfully tested for different noisy configurations of the fingerprints, and proved to be robust with a large basin of attraction. We showed that network topologies with a 2D-Grid arrangement adapt better to the fingerprints spatial structure, outperforming the typical 1D-Ring configuration. An optimal ratio of local connections to random shortcuts that better represent the intrinsic spatial structure of the fingerprints was found, and its influence on the retrieval quality was characterized in a phase diagram. Since the present model is a set of nonlinear equations, it is possible to go beyond the naïve static solution (consisting in matching two fingerprints using a fixed distance threshold value), and a crossing evolution of similarities was shown, leading to the retrieval of the right fingerprint from an apparently more distant candidate. This feature could be very useful for fingerprint verification to discriminate between fingerprints pairs.
Triple Higgs boson production at ILC in the Higgs triplet model
Authors: Cao Jun , Shen Jie-Fen
Published: July 2014

Besides the Standard Model (SM)-like Higgs boson h, the Higgs Triplet Model (HTM) predicts the existence of charged and doubly charged Higgs bosons (H±and H±±). In this paper, we focus on the study of the triple Higgs production at the International Linear Collider (ILC): e-e+→hH+H-and e-e+→hH++H–. We present the production cross-sections and discuss the relevant SM backgrounds. Our numerical results show that, with reasonable parameter values, the values of the cross-sections for two processes can reach the level several fb and tens of fb, respectively. Due to large production cross-section and small SM background, the possible signals of H±and H±±might be detected via these processes in the future ILC experiments.
Analysis of fusion excitation functions of 11Be+209Bi and 15C+232Th reaction through quantum diffusion approach
Authors: Kumari Anju , Kharab Rajesh
Published: July 2014

We have studied the fusion of 11 Be with 209 Bi and 15 C with 232 Th in the energy region around the barrier within the framework of quantum diffusion approach and have found enhancement in fusion cross-section in deep sub-barrier region and a very minor suppression in the above barrier energy region with respect to the corresponding experimental observations. The fusion cross-section is found to be slightly increased for reactions involving 11 Be and 15 C nuclei in comparison to those involving the stable 10 Be and 12 C isotopes, respectively.
Phase-space description of a particle in a quartic double-well potential
Authors: Ceausu-Velcescu Adina , Blaise Paul , Kalmykov Yuri P.
Published: July 2014

The stationary Wigner functions (WFs) have been calculated for particles evolving in a quartic double-well potential V(x) = ax2/2+bx4/4(a < 0 and b > 0), at temperature T. In the high temperature limit, the results totally agree with those obtained using Wigner's perturbative method of deriving quantum corrections to the classical distribution function. Comparison with the perturbative approach allows one to establish the range of applicability of the latter. For illustration, the second moments of the position and momentum have been calculated for the double-well potential. Furthermore, the time-evolution of the WFs for a state initially located at one of the wells has been also investigated to show the tunneling effect.
Effect of oxygen vacancy on the improved photocatalytic activity of Cr-doped TiO2
Authors: Khan Matiullah , Li Jing , Cao Wenbin , Mansoor Bilal , Rehman Fida
Published: July 2014

We employed ab initio calculations to study the effect of various defects on the structural, electronic and optical properties of anatase TiO 2. Single Cr doping at Ti sites introduced isolated Cr  3d states in the band gap of TiO 2. Charge compensated Cr doped model was introduced by simultaneously doping two Cr atoms at Ti sites along with one oxygen vacancy ( Ti 14 O 31 Cr 2). It has been found that Ti 14 O 31 Cr 2 can narrow the band gap significantly and passivate gap states. Removal of the isolated Cr  3d states from the band gap and improved visible light absorption would effectively enhance the photocatalytic activity of Cr doped TiO 2. Our calculations provide reasonable explanation for the previously reported experimental findings.
Characterization ofCaenorhabditis elegansbehavior in response to chemical stress by using hidden Markov model
Authors: Choi Yeontaek , Sim Seungwoo , Lee Sang-Hee
Published: July 2014

The locomotion behavior of Caenorhabditis elegans has been extensively studied to understand the relationship between the changes in the organism's neural activity and the biomechanics. However, so far, we have not yet achieved the understanding. This is because the worm complicatedly responds to the environmental factors, especially chemical stress. Constructing a mathematical model is helpful for the understanding the locomotion behavior in various surrounding conditions. In the present study, we built three hidden Markov models for the crawling behavior of C. elegans in a controlled environment with no chemical treatment and in a polluted environment by formaldehyde, toluene, and benzene (0.1 ppm and 0.5 ppm for each case). The organism's crawling activity was recorded using a digital camcorder for 20 min at a rate of 24 frames per second. All shape patterns were quantified by branch length similarity entropy and classified into five groups by using the self-organizing map. To evaluate and establish the hidden Markov models, we compared correlation coefficients between the simulated behavior (i.e. temporal pattern sequence) generated by the models and the actual crawling behavior. The comparison showed that the hidden Markov models are successful to characterize the crawling behavior. In addition, we briefly discussed the possibility of using the models together with the entropy to develop bio-monitoring systems for determining water quality.
Tunable localized surface plasmon resonances of asymmetricAu/SiO2/Aucross-shape nanobars
Authors: Wan M. L. , Du H. J. , Song Y. L. , Zhou F. Q. , Dai K. J.
Published: July 2014

The plasmonic properties of asymmetric Au / SiO2/ Au sandwiched cross-shape nanobars are investigated theoretically using the discrete dipole approximation (DDA) method. Two localized surface plasmon resonances are observed in the extinction spectra, which perform extreme sensitivity to the length and width of the nanobar and can be tuned easily throughout visible and into near-infrared spectral regions. The local electric fields around the nanobar are calculated and a pure electromagnetic Raman enhancement factor of about 106can be achieved. In addition, compared to a monolayer gold nanobar, it exhibits more "hot spots" and stronger localized electric field enhancements. This plasmonic substrate provides potential applications in surface enhanced Raman scattering (SERS) and nonlinear optical devices.
Noncommutative Bell polynomials, quasideterminants and incidence Hopf algebras
Authors: Ebrahimi-Fard Kurusch , Lundervold Alexander , Manchon Dominique
Published: July 2014

Bell polynomials appear in several combinatorial constructions throughout mathematics. Perhaps most naturally in the combinatorics of set partitions, but also when studying compositions of diffeomorphisms on vector spaces and manifolds, and in the study of cumulants and moments in probability theory. We construct commutative and noncommutative Bell polynomials and explain how they give rise to Faà di Bruno Hopf algebras. We use the language of incidence Hopf algebras, and along the way provide a new description of antipodes in noncommutative incidence Hopf algebras, involving quasideterminants. We also discuss Möbius inversion in certain Hopf algebras built from Bell polynomials.
Classification of genus 1 virtual knots having at most five classical crossings
Authors: Andreevna Akimova Alena , Matveev Sergei Vladimirovich
Published: July 2014

The goal of this paper is to tabulate all genus one prime virtual knots having diagrams with ≤ 5 classical crossings. First, we construct all nonlocal prime knots in the thickened torus T × I which have diagrams with ≤ 5 crossings and admit no destabilizations. Then we use a generalized version of the Kauffman polynomial to prove that all those knots are different. Finally, we convert the knot diagrams in T thus obtained into virtual knot diagrams in the plane.
Energy Harvesting in the Nonlinear Piezoelastic Systems Driven by Harmonic Excitations with Asymmetrical Shape of the Potential Energy
Authors: Kucab Krzysztof , Paśko Wioletta , Majchrowski Klaudiusz , Górski Grzegorz
Published: July 2014

We examine the influence of potential energy asymmetry on the power generated by energy harvesting system. We present results for the system consisting of two masses (magnets) attached to piezoelastic oscillators which vibrate in the magnetic field produced by the magnets attached directly to the harvesting device. The nonlinearity of the system is achieved by the variable strength of the magnetic fields produced by the static magnets. We additionally examine the influence of disproportion between piezoelastic beams stiffness, which is described by the mistuning parameter.
On the geometry of the energy operator in quantum mechanics
Authors: Tejero Prieto Carlos , Vitolo Raffaele
Published: July 2014

We analyze the different ways to define the energy operator in geometric theories of quantum mechanics. In some formulations, the operator contains the scalar curvature as a multiplicative term. We show that such term can be cancelled or added with an arbitrary constant factor, both in the mainstream geometric quantization and in the covariant quantum mechanics developed by Jadczyk and Modugno with several contributions from many authors.
Nonstandard limit theorems and large deviations for the Jacobi beta ensemble
Authors: Nagel Jan
Published: July 2014

In this paper, we show weak convergence of the empirical eigenvalue distribution and of the weighted spectral measure of the Jacobi ensemble, when one or both parameters grow faster than the dimension n. In these cases, the limit measure is given by the Marchenko–Pastur law and the semicircle law, respectively. For the weighted spectral measure, we also prove large deviation principles under this scaling, where the rate functions are those of the other classical ensembles.
Hypoxia-elicited catecholamine release is controlled by L-type as well as N/PQ types of calcium channels in rat embryo chromaffin cells
Authors: Fernández-Morales José-Carlos , Padín Juan-Fernando , Arranz-Tagarro Juan-Alberto , Vestring Stefan , García Antonio G. , de Diego Antonio Miguel G.
Published: July 2014

At early life, the adrenal chromaffin cells respond with a catecholamine surge under hypoxic conditions. This response depends on Ca2+ entry through voltage-activated calcium channels (VACCs). We have investigated here three unresolved questions that concern this response in rat embryo chromaffin cells (ECCs): 1) the relative contribution of L (α1D, Cav1.3), N (α1B, Cav2.2), and PQ (α1A, Cav2.1) to the whole cell Ca2+ current ( ICa); 2) the relative contribution of L and N/PQ channels to the cytosolic Ca2+ elevations triggered by hypoxia (Δ[Ca2+]c); and 3) the role of L and non-L high-VACCs in the regulation of the catecholamine surge occurring during prolonged (1 min) hypoxia exposure of ECCs. Nimodipine halved peak ICa and blocked 60% the total Ca2+ entry during a 50-ms depolarizing pulse to 0 mV (QCa). Combined ω-agatoxin IVA plus ω-conotoxin GVIA (Aga/GVIA) blocked 30% of both ICa peak and QCa. This relative proportion of L- and non-L VACCs was corroborated by Western blot that indicated 55, 23, and 25% relative expression of L, N, and PQ VACCs. Exposure of ECCs to hypoxia elicited a mild but sustained Δ[Ca2+]c; the area of Δ[Ca2+]c was blocked 50% by nifedipine and 10% by Aga/GVIA. Exposure of ECCs to 1-min hypoxia elicited an initial transient burst of amperometric secretory spikes followed by scattered spikes along the time of cell exposure to hypoxia. This bulk response was blocked 85% by nimodipine and 35% by Aga/GVIA. Histograms on secretory spike frequency vs. time indicated a faster initial inactivation when Ca2+ entry took place through N/PQ channels; more sustained secretion but at a lower rate was associated to Ca2+ entry through L channels. The results suggest that the HIS response may initially be controlled by L and P/Q channels, but later on, N/PQ channels inactivate and the delayed HIS response is maintained at lower rate by slow-inactivating L channels.
The CNS glucagon-like peptide-2 receptor in the control of energy balance and glucose homeostasis
Authors: Guan Xinfu
Published: July 2014

The gut-brain axis plays a key role in the control of energy balance and glucose homeostasis. In response to luminal stimulation of macronutrients and microbiota-derived metabolites (secondary bile acids and short chain fatty acids), glucagon-like peptides (GLP-1 and -2) are cosecreted from endocrine L cells in the gut and coreleased from preproglucagonergic neurons in the brain stem. Glucagon-like peptides are proposed as key mediators for bariatric surgery-improved glycemic control and energy balance. Little is known about the GLP-2 receptor (Glp2r)-mediated physiological roles in the control of food intake and glucose homeostasis, yet Glp1r has been studied extensively. This review will highlight the physiological relevance of the central nervous system (CNS) Glp2r in the control of energy balance and glucose homeostasis and focuses on cellular mechanisms underlying the CNS Glp2r-mediated neural circuitry and intracellular PI3K signaling pathway. New evidence (obtained from Glp2r tissue-specific KO mice) indicates that the Glp2r in POMC neurons is essential for suppressing feeding behavior, gastrointestinal motility, and hepatic glucose production. Mice with Glp2r deletion selectively in POMC neurons exhibit hyperphagic behavior, accelerated gastric emptying, glucose intolerance, and hepatic insulin resistance. GLP-2 differentially modulates postsynaptic membrane excitability of hypothalamic POMC neurons in Glp2r- and PI3K-dependent manners. GLP-2 activates the PI3K-Akt-FoxO1 signaling pathway in POMC neurons by Glp2r-p85α interaction. Intracerebroventricular GLP-2 augments glucose tolerance, suppresses glucose production, and enhances insulin sensitivity, which require PI3K (p110α) activation in POMC neurons. Thus, the CNS Glp2r plays a physiological role in the control of food intake and glucose homeostasis. This review will also discuss key questions for future studies.
Oxytocin in the ventromedial hypothalamic nucleus reduces feeding and acutely increases energy expenditure
Authors: Noble Emily E. , Billington Charles J. , Kotz Catherine M. , Wang ChuanFeng
Published: July 2014

Central oxytocin reduces food intake and increases energy expenditure. The ventromedial hypothalamic nucleus (VMN) is associated with energy balance and contains a high density of oxytocin receptors. We hypothesized that oxytocin in the VMN is a negative regulator of energy balance acting to reduce feeding and increase energy expenditure. To test this idea, oxytocin or vehicle was injected directly into the VMN of Sprague-Dawley rats during fasted and nonfasted conditions. Energy expenditure (via indirect calorimetry) and spontaneous physical activity (SPA) were recorded simultaneously. Animals were also exposed to a conditioned taste aversion test, to determine whether oxytocin's effects on food intake were associated with malaise. When food was available during testing, oxytocin-induced elevations in energy expenditure lasted for 1 h, after which overall energy expenditure was reduced. In the absence of food during the testing period, oxytocin similarly increased energy expenditure during the first hour, but differences in 12-h energy expenditure were eliminated, implying that the differences may have been due to the thermic effects of feeding (digestion, absorption, and metabolic processing). Oxytocin acutely elevated SPA and reduced feeding at doses that did not cause a conditioned taste aversion during both the fed and fasted states. Together, these data suggest that oxytocin in the VMN promotes satiety and acutely elevates energy expenditure and SPA and implicates the VMN as a relevant site for the antiobesity effects of oxytocin.
Central role of the BK channel in urinary bladder smooth muscle physiology and pathophysiology
Authors: Petkov Georgi V.
Published: July 2014

The physiological functions of the urinary bladder are to store and periodically expel urine. These tasks are facilitated by the contraction and relaxation of the urinary bladder smooth muscle (UBSM), also known as detrusor smooth muscle, which comprises the bladder wall. The large-conductance voltage- and Ca2+-activated K+(BK, BKCa, MaxiK, Slo1, or KCa1.1) channel is highly expressed in UBSM and is arguably the most important physiologically relevant K+channel that regulates UBSM function. Its significance arises from the fact that the BK channel is the only K+channel that is activated by increases in both voltage and intracellular Ca2+. The BK channels control UBSM excitability and contractility by maintaining the resting membrane potential and shaping the repolarization phase of the spontaneous action potentials that determine UBSM spontaneous rhythmic contractility. In UBSM, these channels have complex regulatory mechanisms involving integrated intracellular Ca2+signals, protein kinases, phosphodiesterases, and close functional interactions with muscarinic and β-adrenergic receptors. BK channel dysfunction is implicated in some forms of bladder pathologies, such as detrusor overactivity, and related overactive bladder. This review article summarizes the current state of knowledge of the functional role of UBSM BK channels under normal and pathophysiological conditions and provides new insight toward the BK channels as targets for pharmacological or genetic control of UBSM function. Modulation of UBSM BK channels can occur by directly or indirectly targeting their regulatory mechanisms, which has the potential to provide novel therapeutic approaches for bladder dysfunction, such as overactive bladder and detrusor underactivity.
Long-term recording of external urethral sphincter EMG activity in unanesthetized, unrestrained rats
Authors: LaPallo Brandon K. , Wolpaw Jonathan R. , Chen Xiang Yang , Carp Jonathan S.
Published: July 2014

The external urethral sphincter muscle (EUS) plays an important role in urinary function and often contributes to urinary dysfunction. EUS study would benefit from methodology for longitudinal recording of electromyographic activity (EMG) in unanesthetized animals, but this muscle is a poor substrate for chronic intramuscular electrodes, and thus the required methodology has not been available. We describe a method for long-term recording of EUS EMG by implantation of fine wires adjacent to the EUS that are secured to the pubic bone. Wires pass subcutaneously to a skull-mounted plug and connect to the recording apparatus by a flexible cable attached to a commutator. A force transducer-mounted cup under a metabolic cage collected urine, allowing recording of EUS EMG and voided urine weight without anesthesia or restraint. Implant durability permitted EUS EMG recording during repeated (up to 3 times weekly) 24-h sessions for more than 8 wk. EMG and voiding properties were stable over weeks 2–8. The degree of EUS phasic activity (bursting) during voiding was highly variable, with an average of 25% of voids not exhibiting bursting. Electrode implantation adjacent to the EUS yielded stable EMG recordings over extended periods and eliminated the confounding effects of anesthesia, physical restraint, and the potential for dislodgment of the chronically implanted intramuscular electrodes. These results show that micturition in unanesthetized, unrestrained rats is usually, but not always, associated with EUS bursting. This methodology is applicable to studying EUS behavior during progression of gradually evolving disease and injury models and in response to therapeutic interventions.
Do large pores in the glomerular capillary wall account for albuminuria in nephrotic states?
Authors: Vuchkova Julijana , Koltun Maria , Greive Kerryn , Comper Wayne D.
Published: July 2014

Albuminuria in nephrotic states is thought to arise from the formation of large pores in the glomerular capillary wall as large hydrodynamic probes, like Ficoll, have increased fractional clearance. In the present study, we tested for large pore formation in a novel manner. We accounted for the rates of plasma elimination as determined for tritium-labeled tracers of uncharged polydisperse Ficoll (radii range: 35–85 Å) and two globular14C-labeled proteins, albumin (radius: 36 Å) and IgG (radius: 55 Å), in control and puromycin aminonucleoside nephrotic (PAN) Sprague-Dawley rats. The plasma elimination rates were then matched to the urinary excretion of these labeled materials ( n = 7). Albumin and IgG plasma retention rates were identical and far enhanced compared with the retention rates of inert transport markers of equivalent hydrodynamic radius; their elimination rate corresponded to the elimination of a 75-Å radius Ficoll ( n = 5) and >105-Å radius dextran ( n = 5). In PAN, they were eliminated as ∼36- and ∼55-Å radii Ficoll, respectively, equivalent to their hydrodynamic radii. In contrast, there was no comparable increase in the elimination rate of Ficoll in PAN. The total plasma clearance of Ficoll in control and PAN rats and the urinary clearance in PAN rats were essentially the same for all radii. On the other hand, the urinary clearance of >45-Å radii Ficoll in controls was considerably lower with increasing radii, demonstrating a postfiltration cellular uptake in controls, which, when inhibited in nephrotic states, would account for apparent large pore formation.
Interactive roles of CD73 and tissue nonspecific alkaline phosphatase in the renal vascular metabolism of 5′-AMP
Authors: Jackson Edwin K. , Cheng Dongmei , Verrier Jonathan D. , Janesko-Feldman Keri , Kochanek Patrick M.
Published: July 2014

CD73 metabolizes extracellular 5′-AMP to adenosine; yet recent experiments in brain tissue suggest that CD73 is not required for the metabolism of 5′-AMP to adenosine because of tissue nonspecific alkaline phosphatase (TNAP), which like CD73 is a GPI-anchored ecto-enyzme with 5′-nucleotidase activity. Because adenosine importantly regulates renovascular function, we investigated whether both TNAP and CD73 are involved in the renovascular metabolism of 5′-AMP. To test this, we examined in isolated, perfused mouse kidneys the metabolism of 5′-AMP (applied to the lumen of the renal vasculature via intrarenal artery administration) to adenosine by measuring renal venous levels of 5′-AMP, adenosine, and inosine (adenosine metabolite) by mass spectrometry. In one study, we compared 5′-AMP metabolism in naive CD73+/+ (wild-type, n = 16) vs. CD73−/− (knockout, n = 16) kidneys; and in a second study, we compared 5′-AMP metabolism in CD73+/+ ( n = 9) vs. CD73−/− ( n = 8) kidneys pretreated with levamisole (1 mmol/l; TNAP inhibitor). In naive kidneys, 5′-AMP increased renal venous 5′-AMP, adenosine, and inosine, and these responses were similar in CD73+/+ vs. CD73−/− kidneys. Levamisole per se did not inhibit renovascular 5′-AMP metabolism; however, in the presence of levamisole, 5′-AMP increased renal venous 5′-AMP threefold more in CD73−/− vs. CD73+/+ kidneys and knockout of CD73 inhibited 5′-induced adenosine and inosine by 81 and 86%, respectively. TNAP mRNA, protein, and activity were similar in CD73+/+ vs. CD73−/− kidneys. In conclusion, CD73 and TNAP play interactive roles to metabolize luminally applied 5′-AMP in the renal vasculature such that inhibition of both is required to inhibit the production of adenosine.
Insights into acidosis-induced regulation of SLC26A4 (pendrin) and SLC4A9 (AE4) transporters using three-dimensional morphometric analysis of β-intercalated cells
Authors: Purkerson Jeffrey M. , Heintz Eric V. , Nakamori Aya , Schwartz George J.
Published: July 2014

The purpose of this study was to examine the three-dimensional (3-D) expression and distribution of anion transporters pendrin (SLC26A4) and anion exchanger (AE)4 (SLC4A9) in β-intercalated cells (β-ICs) of the rabbit cortical collecting duct (CCD) to better characterize the adaptation to acid-base disturbances. Confocal analysis and 3-D reconstruction of β-ICs, using identifiers of the nucleus and zona occludens, permitted the specific orientation of cells from normal, acidotic, and recovering rabbits, so that adaptive changes could be quantified and compared. The pendrin cap likely mediates apical Cl−/HCO3−exchange, but it was also found beneath the zona occludens and in early endosomes, some of which may recycle back to the apical membrane via Rab11a+vesicles. Acidosis reduced the size of the pendrin cap, observed as a large decrease in cap volume above and below the zona occludens, and the volume of the Rab11a+apical recycling compartment. Correction of the acidosis over 12–18 h reversed these changes. Consistent with its proposed function in the basolateral exit of Na+via Na+-HCO3−cotransport, AE4 was expressed as a barrel-like structure in the lateral membrane of β-ICs. Acidosis reduced AE4 expression in β-ICs, but this was rapidly reversed during the recovery from acidosis. The coordinate regulation of pendrin and AE4 during acidosis and recovery is likely to affect the magnitude of acid-base and possibly Na+transport across the CCD. In conclusion, acidosis induces a downregulation of AE expression in β-ICs and a diminished presence of pendrin in apical recycling endosomes.
Motor unit recruitment and firing rate in medial gastrocnemius muscles during external perturbations in standing in humans
Authors: Pollock C. L. , Ivanova T. D. , Hunt M. A. , Garland S. J.
Published: July 2014

There is limited investigation of the interaction between motor unit recruitment and rate coding for modulating force during standing or responding to external perturbations. Fifty-seven motor units were recorded from the medial gastrocnemius muscle with intramuscular electrodes in response to external perturbations in standing. Anteriorly directed perturbations were generated by applying loads in 0.45-kg increments at the pelvis every 25–40 s until 2.25 kg was maintained. Motor unit firing rate was calculated for the initial recruitment load and all subsequent loads during two epochs: 1) dynamic response to perturbation directly following each load drop and 2) maintenance of steady state between perturbations. Joint kinematics and surface electromyography (EMG) from lower extremities and force platform measurements were assessed. Application of the external loads resulted in a significant forward progression of the anterior-posterior center of pressure (AP COP) that was accompanied by modest changes in joint angles (<3°). Surface EMG increased more in medial gastrocnemius than in the other recorded muscles. At initial recruitment, motor unit firing rate immediately after the load drop was significantly lower than during subsequent load drops or during the steady state at the same load. There was a modest increase in motor unit firing rate immediately after the load drop on subsequent load drops associated with regaining balance. There was no effect of maintaining balance with increased load and forward progression of the AP COP on steady-state motor unit firing rate. The medial gastrocnemius utilized primarily motor unit recruitment to achieve the increased levels of activation necessary to maintain standing in the presence of external loads.
Region-specific regulation of voltage-gated intrinsic currents in the developing optic tectum of theXenopustadpole
Authors: Hamodi Ali S. , Pratt Kara G.
Published: July 2014

Across the rostrocaudal (RC) axis of the Xenopus tadpole optic tectum exists a developmental gradient. This gradient has served as a useful model to study many aspects of synapse and dendrite maturation. To compliment these studies, we characterized how the intrinsic excitability, the ease in which a neuron can fire action potentials, might also be changing across the same axis. Whole-cell recordings from tectal neurons at different points along the RC axis revealed a graded increase in intrinsic excitability: compared with neurons at the caudal end of the tectum, neurons at the rostral end fired more action potentials in response to current injection and expressed greater peak Na+and K+currents, the major intrinsic currents in these neurons that underlie the action potential. We also observed, along the same axis and in the same direction, a previously described increase in the amount of synaptic drive received by individual neurons (Wu GY, Malinow R, Cline HT. Science 274: 972–976, 1996). Thus as synaptic activity ramps up across the RC axis, so does intrinsic excitability. The reduction of overall circuit activity induced a compensatory scaling up of peak Na+and K+currents only in the caudal portion of the tectum, suggesting a region-specific, compensatory form of plasticity.
The parietal cortices participate in encoding, short-term memory, and decision-making related to tactile shape
Authors: Rojas-Hortelano Eduardo , Concha Luis , de Lafuente Victor
Published: July 2014

We routinely identify objects with our hands, and the physical attributes of touched objects are often held in short-term memory to aid future decisions. However, the brain structures that selectively process tactile information to encode object shape are not fully identified. In this article we describe the areas within the human cerebral cortex that specialize in encoding, short-term memory, and decision-making related to the shape of objects explored with the hand. We performed event-related functional magnetic resonance imaging in subjects performing a shape discrimination task in which two sequentially presented objects had to be explored to determine whether they had the same shape or not. To control for low-level and nonspecific brain activations, subjects performed a temperature discrimination task in which they compared the temperature of two spheres. Our results show that although a large network of brain structures is engaged in somatosensory processing, it is the areas lining the intraparietal sulcus that selectively participate in encoding, maintaining, and deciding on tactile information related to the shape of objects.