bluuebunny/crossref_metadata_2025 huggingface dataset:
Human H7N9 and H5N1 Influenza Viruses Differ in Induction of Cytokines and Tissue Tropism
Authors: Meliopoulos Victoria A. , Karlsson Erik A. , Kercher Lisa , Cline Troy , Freiden Pamela , Duan Susu , Vogel Peter , Webby Richard J. , Guan Yi , Peiris Malik , Thomas Paul G. , Schultz-Cherry Stacey
Published: September 2014

Since emerging in 2013, the avian-origin H7N9 influenza viruses have resulted in over 400 human infections, leading to 115 deaths to date. Although the epidemiology differs from human highly pathogenic avian H5N1 influenza virus infections, there is a similar rapid progression to acute respiratory distress syndrome. The aim of these studies was to compare the pathological and immunological characteristics of a panel of human H7N9 and H5N1 viruses
in vitro
and
in vivo
. Although there were similarities between particular H5N1 and H7N9 viruses, including association between lethal disease and spread to the alveolar spaces and kidney, there were also strain-specific differences. Both H5N1 and H7N9 viruses are capable of causing lethal infections, with mortality correlating most strongly with wider distribution of viral antigen in the lungs, rather than with traditional measures of virus titer and host responses. Strain-specific differences included hypercytokinemia in H5N1 infections that was not seen with the H7N9 infections regardless of lethality. Conversely, H7N9 viruses showed a greater tropism for respiratory epithelium covering nasal passages and nasopharynx-associated lymphoid tissue than H5N1 viruses, which may explain the enhanced transmission in ferret models. Overall, these studies highlight some distinctive properties of H5N1 and H7N9 viruses in different
in vitro
and
in vivo
models.

IMPORTANCE
The novel avian-origin H7N9 pandemic represents a serious threat to public health. The ability of H7N9 to cause serious lung pathology, leading in some cases to the development of acute respiratory distress syndrome, is of particular concern. Initial reports of H7N9 infection compared them to infections caused by highly pathogenic avian (HPAI) H5N1 viruses. Thus, it is of critical importance to understand the pathology and immunological response to infection with H7N9 compared to HPAI H5N1 viruses. We compared these responses in both
in vitro
and
in vivo
models, and found that H5N1 and H7N9 infections exhibit distinct pathological, immunological, and tissue tropism differences that could explain differences in clinical disease and viral transmission.
Common Features of Mucosal and Peripheral Antibody Responses Elicited by Candidate HIV-1 Vaccines in Rhesus Monkeys
Authors: Li Hualin , Stephenson Kathryn E. , Kang Zi Han , Lavine Christy L. , Seaman Michael S. , Barouch Dan H.
Published: September 2014

Human immunodeficiency virus type 1 (HIV-1) vaccines that elicit protective antibody responses at mucosal sites would be highly desirable. Here, we report that intramuscular immunization of candidate HIV-1 vaccine vectors and purified Env proteins elicited potent and durable humoral immune responses in colorectal mucosa in rhesus monkeys. The kinetics, isotypes, functionality, and epitope specificity of these mucosal antibody responses were similar to those of peripheral responses in serum. These data suggest a close immunological relationship between mucosal and systemic antibody responses following vaccination in primates.
Induction of Broadly Reactive Anti-Hemagglutinin Stalk Antibodies by an H5N1 Vaccine in Humans
Authors: Nachbagauer Raffael , Wohlbold Teddy John , Hirsh Ariana , Hai Rong , Sjursen Haakon , Palese Peter , Cox Rebecca J. , Krammer Florian
Published: September 2014

Influenza virus infections are a major public health concern and cause significant morbidity and mortality worldwide. Current vaccines are effective but strain specific due to their focus on the immunodominant globular head domain of the hemagglutinin (HA). It has been hypothesized that sequential exposure of humans to hemagglutinins with divergent globular head domains but conserved stalk domains could refocus the immune response to broadly neutralizing epitopes in the stalk. Humans have preexisting immunity against H1 (group 1 hemagglutinin), and vaccination with H5 HA (also group 1)—which has a divergent globular head domain but a similar stalk domain—represents one such sequential-exposure scenario. To test this hypothesis, we used novel reagents based on chimeric hemagglutinins to screen sera from an H5N1 clinical trial for induction of stalk-specific antibodies by quantitative enzyme-linked immunosorbent assay (ELISA) and neutralization assays. Importantly, we also investigated the biological activity of these antibodies in a passive transfer in a mouse challenge model. We found that the H5N1 vaccine induced high titers of stalk-reactive antibodies which were biologically active and protective in the passive-transfer experiment. The induced response showed exceptional breadth toward divergent group 1 hemagglutinins but did not extend to group 2 hemagglutinins. These data provide evidence for the hypothesis that sequential exposure to hemagglutinins with divergent globular head domains but conserved stalk domains can refocus the immune response toward the conserved stalk domain. Furthermore, the results support the concept of a chimeric hemagglutinin universal influenza virus vaccine strategy that is based on the same principle.

IMPORTANCE
Influenza virus vaccines have to be reformulated and readministered on an annual basis. The development of a universal influenza virus vaccine could abolish the need for this cumbersome and costly process and would also enhance our pandemic preparedness. This study addressed the following questions, which are essential for the development of a hemagglutinin stalk-based universal influenza virus vaccine. (i) Can stalk-reactive antibodies be boosted by vaccination with divergent HAs that share conserved epitopes? (ii) How long-lived are these vaccine-induced stalk-reactive antibody responses? (iii) What is the breadth of this reactivity? (iv) Are these antibodies functional and protective? Our results further strengthen the concept of induction of stalk-reactive antibodies by sequential exposure to hemagglutinin immunogens with conserved stalk and divergent head domains. A universal influenza virus vaccine based on the same principles seems possible and might have a significant impact on global human health.
Cholesterol-Dependent Membrane Fusion Induced by the gp41 Membrane-Proximal External Region–Transmembrane Domain Connection Suggests a Mechanism for Broad HIV-1 Neutralization
Authors: Apellániz Beatriz , Rujas Edurne , Carravilla Pablo , Requejo-Isidro José , Huarte Nerea , Domene Carmen , Nieva José L.
Published: September 2014

The HIV-1 glycoprotein 41 promotes fusion of the viral membrane with that of the target cell. Structural, biochemical, and biophysical studies suggest that its membrane-proximal external region (MPER) may interact with the HIV-1 membrane and induce its disruption and/or deformation during the process. However, the high cholesterol content of the envelope (ca. 40 to 50 mol%) imparts high rigidity, thereby acting against lipid bilayer restructuring. Here, based on the outcome of vesicle stability assays, all-atom molecular dynamics simulations, and atomic force microscopy observations, we propose that the conserved sequence connecting the MPER with the N-terminal residues of the transmembrane domain (TMD) is involved in HIV-1 fusion. This junction would function by inducing phospholipid protrusion and acyl-chain splay in the cholesterol-enriched rigid envelope. Supporting the functional relevance of such a mechanism, membrane fusion was inhibited by the broadly neutralizing 4E10 antibody but not by a nonneutralizing variant with the CDR-H3 loop deleted. We conclude that the MPER-TMD junction embodies an envelope-disrupting C-terminal fusion peptide that can be targeted by broadly neutralizing antibodies.

IMPORTANCE
Fusion of the cholesterol-enriched viral envelope with the cell membrane marks the beginning of the infectious HIV-1 replicative cycle. Consequently, the Env glycoprotein-mediated fusion function constitutes an important clinical target for inhibitors and preventive vaccines. Antibodies 4E10 and 10E8 bind to one Env vulnerability site located at the gp41 membrane-proximal external region (MPER)–transmembrane domain (TMD) junction and block infection. These antibodies display broad viral neutralization, which underscores the conservation and functionality of the MPER-TMD region. In this work, we combined biochemical assays with molecular dynamics simulations and microscopy observations to characterize the unprecedented fusogenic activity of the MPER-TMD junction. The fact that such activity is dependent on cholesterol and inhibited by the broadly neutralizing 4E10 antibody emphasizes its physiological relevance. Discovery of this functional element adds to our understanding of the mechanisms underlying HIV-1 infection and its blocking by antibodies.
Early Preservation of CXCR5
+
PD-1
+
Helper T Cells and B Cell Activation Predict the Breadth of Neutralizing Antibody Responses in Chronic HIV-1 Infection
Authors: Cohen Kristen , Altfeld Marcus , Alter Galit , Stamatatos Leonidas
Published: September 2014

Much is known about the characteristics of broadly neutralizing antibodies (bNAbs) generated during HIV-1 infection, but little is known about immunological mechanisms responsible for their development in only a minority of those infected by HIV-1. By monitoring longitudinally a cohort of HIV-1-infected subjects, we observed that the preservation of CXCR5
+
CD4
+
T helper cell frequencies and activation status of B cells during the first year of infection correlates with the maximum breadth of plasma neutralizing antibody responses during chronic infection independently of viral load. Although, during the first year of infection, no differences were observed in the abilities of peripheral CXCR5
+
CD4
+
T helper cells to induce antibody secretion by autologous naive B cells, higher frequencies of class-switched antibodies were detected in cocultures of CXCR5
+
CD4
+
T and B cells from the subjects who later developed broadly neutralizing antibody responses than those who did not. Furthermore, B cells from the former subjects had higher expression of
AICDA
than B cells from the latter subjects, and transcript levels correlated with the frequency of CXCR5
+
CD4
+
T cells. Thus, the early preservation of CXCR5
+
CD4
+
T cells and B cell function are central to the development of bNAbs. Our study provides a possible explanation for their infrequent generation during HIV-1 infection.

IMPORTANCE
Broadly neutralizing antibodies are developed by HIV-1-infected subjects, but so far (and despite intensive efforts over the past 3 decades) they have not been elicited by immunization. Understanding how bNAbs are generated during natural HIV-1 infection and why only some HIV-1-infected subjects generate such antibodies will assist our efforts to elicit bNAbs by immunization. CXCR5
+
PD-1
+
CD4
+
T cells are critical for the development of high-affinity antigen-specific antibody responses. In our study, we found that the HIV-1-infected subjects who develop bNAbs have a higher frequency of peripheral CXCR5
+
PD-1
+
CD4
+
T cells in early infection and also that this frequency mirrored what was observed in uninfected subjects and correlated with the level of B cell activation across subjects. Our study highlights the critical role helper T cell function has in the elicitation of broadly neutralizing antibody responses in the context of HIV infection.
Herpes Simplex Virus Internalization into Epithelial Cells Requires Na
+
/H
+
Exchangers and p21-Activated Kinases but neither Clathrin- nor Caveolin-Mediated Endocytosis
Authors: Devadas Deepika , Koithan Thalea , Diestel Randi , Prank Ute , Sodeik Beate , Döhner Katinka
Published: September 2014

Herpes simplex virus 1 (HSV-1) is an alphaherpesvirus that has been reported to infect some epithelial cell types by fusion at the plasma membrane but others by endocytosis. To determine the molecular mechanisms of productive HSV-1 cell entry, we perturbed key endocytosis host factors using specific inhibitors, RNA interference (RNAi), or overexpression of dominant negative proteins and investigated their effects on HSV-1 infection in the permissive epithelial cell lines Vero, HeLa, HEp-2, and PtK
2
. HSV-1 internalization required neither endosomal acidification nor clathrin- or caveolin-mediated endocytosis. In contrast, HSV-1 gene expression and internalization were significantly reduced after treatment with 5-(
N
-ethyl-
N
-isopropyl)amiloride (EIPA). EIPA blocks the activity of Na
+
/H
+
exchangers, which are plasma membrane proteins implicated in all forms of macropinocytosis. HSV-1 internalization furthermore required the function of p21-activated kinases that contribute to macropinosome formation. However, in contrast to some forms of macropinocytosis, HSV-1 did not enlist the activities of protein kinase C (PKC), tyrosine kinases, C-terminal binding protein 1, or dynamin to activate its internalization. These data suggest that HSV-1 depends on Na
+
/H
+
exchangers and p21-activated kinases either for macropinocytosis or for local actin rearrangements required for fusion at the plasma membrane or subsequent passage through the actin cortex underneath the plasma membrane.

IMPORTANCE
After initial replication in epithelial cells, herpes simplex viruses (HSVs) establish latent infections in neurons innervating these regions. Upon primary infection and reactivation from latency, HSVs cause many human skin and neurological diseases, particularly in immunocompromised hosts, despite the availability of effective antiviral drugs. Many viruses use macropinocytosis for virus internalization, and many host factors mediating this entry route have been identified, although the specific perturbation profiles vary for different host and viral cargo. In addition to an established entry pathway via acidic endosomes, we show here that HSV-1 internalization depended on sodium-proton exchangers at the plasma membrane and p21-activated kinases. These results suggest that HSV-1 requires a reorganization of the cortical actin cytoskeleton, either for productive cell entry via pH-independent fusion from macropinosomes or for fusion at the plasma membrane, and subsequent cytosolic passage to microtubules that mediate capsid transport to the nucleus for genome uncoating and replication.
Transcutaneous electrical nerve stimulation as adjunct to primary care management for tennis elbow: pragmatic randomised controlled trial (TATE trial)
Authors: Chesterton Linda S , Lewis A Martyn , Sim Julius , Mallen Christian D , Mason Elizabeth E , Hay Elaine M , van der Windt Daniëlle A
Published: September 2014

STUDY QUESTION

Can transcutaneous electrical nerve stimulation (TENS), as a patient controlled adjunct to primary care management for tennis elbow, provide superior pain relief to primary care management alone.

SUMMARY ANSWER

TENS conferred no additional clinical benefit over primary care management consisting of information and advice on analgesia and exercise for patients with tennis elbow, probably partly owing to poor adherence to treatment recommendations.

WHAT IS KNOWN AND WHAT THIS PAPER ADDS

A need exists for safe, self administered interventions to provide pain relief for patients with tennis elbow. TENS as an adjunct to primary care management failed to show any additional pain relief compared with primary care management alone.
Barriers and facilitators to implementation of the Liverpool Care Pathway in the Netherlands: a qualitative study
Authors: Raijmakers Natasja , Dekkers Anneke , Galesloot Cilia , van Zuylen Lia , van der Heide Agnes
Published: September 2014

Objectives

The Liverpool Care Pathway (LCP) is a quality instrument for the dying patient. This study evaluates barriers and facilitators to its implementation in the Netherlands from the perspective of key stakeholders, to inform future implementation processes.

Methods

An interview study was conducted among 28 stakeholders involved in implementation of the LCP in the Netherlands, followed by a consecutive focus group with 8 interviewees to discuss and validate the findings of the interview study. Interviews were conducted by telephone and the notes taken during the interviews and focus group were transcribed into non-verbatim transcripts. Data collected during the interviews and focus group were evaluated using thematic analysis.

Results

According to the stakeholders, a context analysis prior to implementation was useful to find the appropriate orientation to adequately motivate healthcare professionals as well as management. The main contributing factors were the quality of the LCP (including its evidence-based character and completeness), and that it fitted the needs of healthcare professionals. During the implementation phase, a multidisciplinary project team, competent support and continuous monitoring were identified as important facilitators. Furthermore, for successful implementation, a facilitator working in liaison with others was helpful. To guarantee sustainability of the use of the LCP, it was important to disentangle tasks from the project leader and formally integrate these into the quality systems of the organisation.

Conclusions

The Dutch experience with large-scale implementation of the LCP has identified important barriers and facilitators to the implementation of a quality instrument within palliative care. To successfully implement such a promising instrument, liaison with others is important. The sense of being part of a process of improvement is valuable, while consolidation of this idea contributes to successful implementation.
Satisfiability by Maxwell-Boltzmann and Bose-Einstein Statistical Distributions
Authors: Angione Claudio , Occhipinti Annalisa , Nicosia Giuseppe
Published: September 2014

Recent studies in theoretical computer science have exploited new algorithms and methodologies based on statistical physics for investigating the structure and the properties of the Satisfiability (SAT) problem. We propose a characterization of the SAT problem as a physical system, using both quantum and classical statistical-physical models. We associate a graph to an SAT instance and we prove that a Bose-Einstein condensation occurs in the instance with higher probability if the quantum distribution is adopted in the generation of the graph. Conversely, the fit-get-rich behavior is more likely if we adopt the Maxwell-Boltzmann distribution. Our method allows a comprehensive analysis of the SAT problem based on a new definition of entropy of an instance, without requiring the computation of its truth assignments. The entropy of an SAT instance increases in the satisfiability region as the number of free variables in the instance increases. Finally, we develop six new solvers for the MaxSAT problem based on quantum and classical statistical distributions, and we test them on random SAT instances, with competitive results. We experimentally prove that the performance of the solvers based on the two distributions depends on the criterion used to flag clauses as satisfied in the SAT solving process.
Performance overhead of KVM on Linux 3.9 on ARM cortex-a15
Authors: Rasmusson Lars , Corcoran Diarmuid
Published: September 2014

A number of simple performance measurements on network, CPU and disk speed were done on a dual ARM Cortex-A15 machine running Linux inside a KVM virtual machine that uses virtio disk and networking. Unexpected behaviour was observed in the CPU and memory intensive benchmarks, and in the networking benchmarks. The average overhead of running inside KVM is between zero and 30 percent when the host is lightly loaded (running only the system software and the necessary qemu-system-arm virtualization code), but the relative overhead increases when both host and VM is busy. We conjecture that this is related to the scheduling inside the host Linux.
Oxytocin and bone
Authors: Colaianni Graziana , Sun Li , Zaidi Mone , Zallone Alberta
Published: September 2014

One of the most meaningful results recently achieved in bone research has been to reveal that the pituitary hormones have profound effect on bone, so that the pituitary-bone axis has become one of the major topics in skeletal physiology. Here, we discuss the relevant evidence about the posterior pituitary hormone oxytocin (OT), previously thought to exclusively regulate parturition and breastfeeding, which has recently been established to directly regulate bone mass. Both osteoblasts and osteoclasts express OT receptors (OTR), whose stimulation enhances bone mass. Consistent with this, mice deficient in OT or OTR display profoundly impaired bone formation. In contrast, bone resorption remains unaffected in OT deficiency because, even while OT stimulates the genesis of osteoclasts, it inhibits their resorptive function. Furthermore, in addition to its origin from the pituitary, OT is also produced by bone marrow osteoblasts acting as paracrine-autocrine regulator of bone formation modulated by estrogens. In turn, the power of estrogen to increase bone mass is OTR-dependent. Therefore, OTR−/−mice injected with 17β-estradiol do not show any effects on bone formation parameters, while the same treatment increases bone mass in wild-type mice. These findings together provide evidence for an anabolic action of OT in regulating bone mass and suggest that bone marrow OT may enhance the bone-forming action of estrogen through an autocrine circuit. This established new physiological role for OT in the maintenance of skeletal integrity further suggests the potential use of this hormone for the treatment of osteoporosis.
Effects of metabolic acidosis on intracellular pH responses in multiple cell types
Authors: Salameh Ahlam Ibrahim , Ruffin Vernon A. , Boron Walter F.
Published: September 2014

Metabolic acidosis (MAc), a decrease in extracellular pH (pHo) caused by a decrease in [HCO3−]oat a fixed [CO2]o, is a common clinical condition and causes intracellular pH (pHi) to fall. Although previous work has suggested that MAc-induced decreases in pHi(ΔpHi) differ among cell types, what is not clear is the extent to which these differences are the result of the wide variety of methodologies employed by various investigators. In the present study, we evaluated the effects of two sequential MAc challenges (MAc1and MAc2) on pHiin 10 cell types/lines: primary-cultured hippocampal (HCN) neurons and astrocytes (HCA), primary-cultured medullary raphé (MRN) neurons, and astrocytes (MRA), CT26 colon cancer, the C2C12 skeletal muscles, primary-cultured bone marrow-derived macrophages (BMDM) and dendritic cells (BMDC), Ink4a/ARF-null melanocytes, and XB-2 keratinocytes. We monitor pHiusing ratiometric fluorescence imaging of 2′,7′-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein while imposing MAc: lowering (pHo) from 7.4 to 7.2 by decreasing [HCO3−]ofrom 22 to 14 mM at 5% CO2for 7 min. After MAc1, we return cells to the control solution for 10 min and impose MAc2. Using our definition of MAc resistance [(ΔpHi/ΔpHo) ≤ 40%], during MAc1, ∼70% of CT26 and ∼50% of C2C12 are MAc-resistant, whereas the other cell types are predominantly MAc-sensitive. During MAc2, some cells adapt [(ΔpHi/ΔpHo)2< (ΔpHi/ΔpHo)1], particularly HCA, C2C12, and BMDC. Most maintain consistent responses [(ΔpHi/ΔpHo)2≅ (ΔpHi/ΔpHo)1], and a few decompensate [(ΔpHi/ΔpHo)2>(ΔpHi/ΔpHo)1], particularly HCN, C2C12, and XB-2. Thus, responses to twin MAc challenges depend both on the individual cell and cell type.
Prostasin interacts with the epithelial Na+channel and facilitates cleavage of the γ-subunit by a second protease
Authors: Carattino Marcelo D. , Mueller Gunhild M. , Palmer Lawrence G. , Frindt Gustavo , Rued Anna C. , Hughey Rebecca P. , Kleyman Thomas R.
Published: September 2014

During maturation, the α- and γ-subunits of the epithelial Na+channel (ENaC) undergo proteolytic processing by furin. Cleavage of the γ-subunit by furin at the consensus site γRKRR143and subsequent cleavage by a second protease at a distal site strongly activate the channel. For example, coexpression of prostasin with ENaC increases both channel function and cleavage at the γRKRK186site. We generated a polyclonal antibody that recognizes the region 144–186 in the γ-subunit (anti-γ43) to determine whether prostasin promotes the release of the intervening tract between the putative furin and γRKRK186cleavage sites. Anti-γ43 precipitated both full-length (93 kDa) and furin-processed (83 kDa) γ-subunits from extracts obtained from oocytes expressing αβHA-γ-V5 channels, but only the full-length (93 kDa) γ-subunit from oocytes expressing αβHA-γ-V5 channels and either wild-type or a catalytically inactive prostasin. Although both wild-type and catalytically inactive prostasin activated ENaCs in an aprotinin-sensitive manner, only wild-type prostasin bound to aprotinin beads, suggesting that catalytically inactive prostasin facilitates the cleavage of the γ-subunit by an endogenous protease in Xenopus oocytes. As dietary salt restriction increases cleavage of the renal γ-subunit, we assessed release of the 43-mer inhibitory tract on rats fed a low-Na+diet. We found that a low-Na+diet increased γ-subunit cleavage detected with the anti-γ antibody and dramatically reduced the fraction precipitated with the anti-γ43 antibody. Our results suggest that the inhibitory tract dissociates from the γ-subunit in kidneys from rats on a low-Na+diet.
Dynamic, size-selective effects of protamine sulfate and hyaluronidase on the rat glomerular filtration barrier in vivo
Authors: Sverrisson Kristinn , Axelsson Josefin , Rippe Anna , Asgeirsson Daniel , Rippe Bengt
Published: September 2014

The proteinuric actions of protamine sulfate (PS) have classically been, at least partly, attributed to alterations of the negatively charged glomerular endothelial glycocalyx. To investigate whether the charge-selective properties of the glomerular filtration barrier (GFB) would be altered by PS, we assessed the glomerular sieving of conventional, uncharged, polydispersed Ficoll (n-Ficoll) compared with charge modified, conformationally intact, anionic (carboxymethylated) Ficoll (a-Ficoll) before and after systemic infusions of PS in rats. For comparison, we also investigated the impact of hyaluronidase (hyase), which partially degrades the glycocalyx, on GFB permeability. In anaesthetized Wistar rats, blood access was achieved, and the left ureter was cannulated for urine collection. Rats were infused with either n-Ficoll or a-Ficoll before and during systemic infusions with either PS or hyase. Plasma and urine samples were taken repeatedly and analyzed by high-performance size exclusion chromatography to assess glomerular sieving coefficients (θ) for Ficoll (radius 10–80 Å). The GFB showed a significant glomerular charge selectivity for Ficoll molecules of radius 20–35 Å. PS and hyase infusions reversibly increased θ for large Ficoll molecules (Ficoll molecules of radius 50–80 Å). Thus, for PS, θ for a-Ficoll molecules of radius 70 Å increased from 2.47 × 10−5± 1.1−5to 7.25 × 10−5± 1.1−5( P < 0.05) at 15 min. For hyase, changes in a-Ficoll molecules of radius 50–80 Å were, however, not statistically significant. Neither PS nor hyase had any effect on θ for n-Ficoll molecules of radius 20–45 Å or a-Ficoll molecules of radius 20–45 Å. It is concluded that systemically administered PS and hyase in moderate doses dynamically decreased the size selectivity of the rat GFB without affecting its charge selective properties.
Functional properties and connective tissue content of pediatric human detrusor muscle
Authors: Johal Navroop , Wood Dan N. , Wagg Adrian S. , Cuckow Peter , Fry Christopher H.
Published: September 2014

The functional properties of human pediatric detrusor smooth muscle are poorly described, in contrast to those of adult tissue. Characterization is necessary for more informed management options of bladder dysfunction in children. We therefore compared the histological, contractile, intracellular Ca2+concentration responses and biomechanical properties of detrusor biopsy samples from pediatric (3–48 mo) and adults (40–60 yr) patients who had functionally normal bladders and were undergoing open surgery. The smooth muscle fraction of biopsies was isolated to measure proportions of smooth muscle and connective tissue (van Gieson stain); in muscle strips, isometric tension to contractile agonists or electrical field stimulation and their passive biomechanical properties; in isolated myocytes, intracellular Ca2+concentration responses to agonists. Pediatric detrusor tissue compared with adult tissue showed several differences: a smaller smooth muscle-to-connective tissue ratio, similar contractures to carbachol or α,β-methylene ATP when corrected for smooth muscle content, and similar intracellular Ca2+transients to carbachol, α,β-methylene ATP, raised K+concentration or caffeine, but smaller nerve-mediated contractions and greater passive stiffness with slower stress relaxation. In particular, there were significant atropine-resistant nerve-mediated contractions in pediatric samples. Detrusor smooth muscle from functionally normal pediatric human bladders is less contractile than that from adult bladders and exhibits greater passive stiffness. Reduced bladder contractile function is not due to reduced smooth muscle contractility but to greater connective tissue deposition and to functional denervation. Significant atropine resistance in pediatric detrusor, unlike in adult tissue, demonstrates a different profile of functional neurotransmitter activation. These data have implications for the management of pediatric bladder function by therapeutic approaches.
Vascular geometry and oxygen diffusion in the vicinity of artery-vein pairs in the kidney
Authors: Ngo Jennifer P. , Kar Saptarshi , Kett Michelle M. , Gardiner Bruce S. , Pearson James T. , Smith David W. , Ludbrook John , Bertram John F. , Evans Roger G.
Published: September 2014

Renal arterial-to-venous (AV) oxygen shunting limits oxygen delivery to renal tissue. To better understand how oxygen in arterial blood can bypass renal tissue, we quantified the radial geometry of AV pairs and how it differs according to arterial diameter and anatomic location. We then estimated diffusion of oxygen in the vicinity of arteries of typical geometry using a computational model. The kidneys of six rats were perfusion fixed, and the vasculature was filled with silicone rubber (Microfil). A single section was chosen from each kidney, and all arteries ( n = 1,628) were identified. Intrarenal arteries were largely divisible into two “types,” characterized by the presence or absence of a close physical relationship with a paired vein. Arteries with a close physical relationship with a paired vein were more likely to have a larger rather than smaller diameter, and more likely to be in the inner-cortex than the mid- or outer cortex. Computational simulations indicated that direct diffusion of oxygen from an artery to a paired vein can only occur when the two vessels have a close physical relationship. However, even in the absence of this close relationship oxygen can diffuse from an artery to periarteriolar capillaries and venules. Thus AV oxygen shunting in the proximal preglomerular circulation is dominated by direct diffusion of oxygen to a paired vein. In the distal preglomerular circulation, it may be sustained by diffusion of oxygen from arteries to capillaries and venules close to the artery wall, which is subsequently transported to renal veins by convection.
Transcriptional regulation of urate transportosome member SLC2A9 by nuclear receptor HNF4α
Authors: Prestin Katharina , Wolf Stephanie , Feldtmann Rico , Hussner Janine , Geissler Ingrid , Rimmbach Christian , Kroemer Heyo K. , Zimmermann Uwe , zu Schwabedissen Henriette E. Meyer
Published: September 2014

Renal tubular handling of urate is realized by a network of uptake and efflux transporters, including members of drug transporter families such as solute carrier proteins and ATP-binding cassette transporters. Solute carrier family 2, member 9 (SLC2A9), is one key factor of this so called “urate transportosome.” The aim of the present study was to understand the transcriptional regulation of SLC2A9 and to test whether identified factors might contribute to a coordinated transcriptional regulation of the transporters involved in urate handling. In silico analysis and cell-based reporter gene assays identified a hepatocyte nuclear factor (HNF)4α-binding site in the promoter of SLC2A9 isoform 1, whose activity was enhanced by transient HNF4α overexpression, whereas mutation of the binding site diminished activation. HNF4α overexpression induced endogenous SLC2A9 expression in vitro. The in vivo role of HNF4α in the modulation of renal SLC2A9 gene expression was supported by findings of quantitative real-time RT-PCR analyses and chromatin immunoprecipitation assays. Indeed, mRNA expression of SLC2A9 and HNF4α in human kidney samples was significantly correlated. We also showed that in renal clear cell carcinoma, downregulation of HNF4α mRNA and protein expression was associated with a significant decline in expression of the transporter. Taken together, our data suggest that nuclear receptor family member HNF4α contributes to the transcriptional regulation of SLC2A9 isoform 1. Since HNF4α has previously been assumed to be a modulator of several urate transporters, our findings support the notion that there could be a transcriptional network providing synchronized regulation of the functional network of the urate transportosome.
Modulation of alpha power at encoding and retrieval tracks the precision of visual short-term memory
Authors: Poliakov E. , Stokes M. G. , Woolrich M. W. , Mantini D. , Astle D. E.
Published: September 2014

Our ability to hold information in mind is strictly limited. We sought to understand the relationship between oscillatory brain activity and the allocation of resources within visual short-term memory (VSTM). Participants attempted to remember target arrows embedded among distracters and used a continuous method of responding to report their memory for a cued target item. Trial-to-trial variability in the absolute circular accuracy with which participants could report the target was predicted by event-related alpha synchronization during initial processing of the memoranda and by alpha desynchronization during the retrieval of those items from VSTM. Using a model-based approach, we were also able to explore further which parameters of VSTM-guided behavior were most influenced by alpha band changes. Alpha synchronization during item processing enhanced the precision with which an item could be retained without affecting the likelihood of an item being represented per se (as indexed by the guessing rate). Importantly, our data outline a neural mechanism that mirrors the precision with which items are retained; the greater the alpha power enhancement during encoding, the greater the precision with which that item can be retained.
New insights into short-term synaptic facilitation at the frog neuromuscular junction
Authors: Ma Jun , Kelly Lauren , Ingram Justin , Price Thomas J. , Meriney Stephen D. , Dittrich Markus
Published: September 2014

Short-term synaptic facilitation occurs during high-frequency stimulation, is known to be dependent on presynaptic calcium ions, and persists for tens of milliseconds after a presynaptic action potential. We have used the frog neuromuscular junction as a model synapse for both experimental and computer simulation studies aimed at testing various mechanistic hypotheses proposed to underlie short-term synaptic facilitation. Building off our recently reported excess-calcium-binding-site model of synaptic vesicle release at the frog neuromuscular junction (Dittrich M, Pattillo JM, King JD, Cho S, Stiles JR, Meriney SD. Biophys J 104: 2751–2763, 2013), we have investigated several mechanisms of short-term facilitation at the frog neuromuscular junction. Our studies place constraints on previously proposed facilitation mechanisms and conclude that the presence of a second class of calcium sensor proteins distinct from synaptotagmin can explain known properties of facilitation observed at the frog neuromuscular junction. We were further able to identify a novel facilitation mechanism, which relied on the persistent binding of calcium-bound synaptotagmin molecules to lipids of the presynaptic membrane. In a real physiological context, both mechanisms identified in our study (and perhaps others) may act simultaneously to cause the experimentally observed facilitation. In summary, using a combination of computer simulations and physiological recordings, we have developed a stochastic computer model of synaptic transmission at the frog neuromuscular junction, which sheds light on the facilitation mechanisms in this model synapse.
Perturbation-evoked responses in primary motor cortex are modulated by behavioral context
Authors: Omrani Mohsen , Pruszynski J. Andrew , Murnaghan Chantelle D. , Scott Stephen H.
Published: September 2014

Corrective responses to external perturbations are sensitive to the behavioral task being performed. It is believed that primary motor cortex (M1) forms part of a transcortical pathway that contributes to this sensitivity. Previous work has identified two distinct phases in the perturbation response of M1 neurons, an initial response starting ∼20 ms after perturbation onset that does not depend on the intended motor action and a task-dependent response that begins ∼40 ms after perturbation onset. However, this invariant initial response may reflect ongoing postural control or a task-independent response to the perturbation. The present study tested these two possibilities by examining if being engaged in an ongoing postural task before perturbation onset modulated the initial perturbation response in M1. Specifically, mechanical perturbations were applied to the shoulder and/or elbow while the monkey maintained its hand at a central target or when it was watching a movie and not required to respond to the perturbation. As expected, corrective movements, muscle stretch responses, and M1 population activity in the late perturbation epoch were all significantly diminished in the movie task. Strikingly, initial perturbation responses (<40 ms postperturbation) remained the same across tasks, suggesting that the initial phase of M1 activity constitutes a task-independent response that is sensitive to the properties of the mechanical perturbation but not the goal of the ongoing motor task.
Regular-spiking cells in the presubiculum are hyperexcitable in a rat model of temporal lobe epilepsy
Authors: Abbasi Saad , Kumar Sanjay S.
Published: September 2014

Temporal lobe epilepsy (TLE) is the most common form of adult epilepsy, characterized by recurrent seizures originating in the temporal lobes. Here, we examine TLE-related changes in the presubiculum (PrS), a less-studied parahippocampal structure that both receives inputs from and projects to regions affected by TLE. We assessed the state of PrS neurons in TLE electrophysiologically to determine which of the previously identified cell types were rendered hyperexcitable in epileptic rats and whether their intrinsic and/or synaptic properties were altered. Cell types were characterized based on action potential discharge profiles followed by unsupervised hierarchical clustering. PrS neurons in epileptic animals could be divided into three major groups comprising of regular-spiking (RS), irregular-spiking (IR), and fast-adapting (FA) cells. RS cells, the predominant cell type encountered in PrS, were the only cells that were hyperexcitable in TLE. These neurons were previously identified as sending long-range axonal projections to neighboring structures including medial entorhinal area (MEA), and alterations in intrinsic properties increased their propensity for sustained firing of action potentials. Frequency and amplitude of both spontaneous excitatory and inhibitory synaptic events were reduced. Further analysis of nonaction potential-dependent miniature currents (in tetrodotoxin) indicated that reduction in excitatory drive to these neurons was mediated by decreased activity of excitatory neurons that synapse with RS cells concomitant with reduced activity of inhibitory neurons. Alterations in physiological properties of PrS neurons and their ensuing hyperexcitability could entrain parahippocampal structures downstream of PrS, including the MEA, contributing to temporal lobe epileptogenesis.
Electrical coupling and innexin expression in the stomatogastric ganglion of the crabCancer borealis
Authors: Shruti Sonal , Schulz David J. , Lett Kawasi M. , Marder Eve
Published: September 2014

Gap junctions are intercellular channels that allow for the movement of small molecules and ions between the cytoplasm of adjacent cells and form electrical synapses between neurons. In invertebrates, the gap junction proteins are coded for by the innexin family of genes. The stomatogastric ganglion (STG) in the crab Cancer borealis contains a small number of identified and electrically coupled neurons. We identified Innexin 1 ( Inx1), Innexin 2 (Inx2), Innexin 3 (Inx3), Innexin 4 ( Inx4), Innexin 5 (Inx5), and Innexin 6 ( Inx6) members of the C. borealis innexin family. We also identified six members of the innexin family from the lobster Homarus americanus transcriptome. These innexins show significant sequence similarity to other arthropod innexins. Using in situ hybridization and reverse transcriptase-quantitative PCR (RT-qPCR), we determined that all the cells in the crab STG express multiple innexin genes. Electrophysiological recordings of coupling coefficients between identified pairs of pyloric dilator (PD) cells and PD-lateral posterior gastric (LPG) neurons show that the PD-PD electrical synapse is nonrectifying while the PD-LPG synapse is apparently strongly rectifying.
The effects of training breadth on motor generalization
Authors: Berniker Max , Mirzaei Hamid , Kording Konrad P.
Published: September 2014

To generate new movements, we have to generalize what we have learned from previously practiced movements. An important question, therefore, is how the breadth of training affects generalization: does practicing a broad or narrow range of movements lead to better generalization? We address this question with a force field learning experiment. One group adapted while making many reaches in a small region (narrow group), and another group adapted while making reaches in a large region (broad group). Subsequently, both groups were tested for their ability to generalize without visual feedback. Not surprisingly, the narrow group exhibited smaller adaptation errors, yet they did not generalize any better than the broad group. Path errors during generalization were indistinguishable across the two groups, whereas the broad group exhibited reduced terminal errors. These findings indicate that overall, practicing a variety of movements is advantageous for performance during generalization; movement paths are not hindered, and terminal errors are superior. Moreover, the evidence suggests a dissociation between the ability to generalize information about a novel dynamic disturbance, which generalizes narrowly, and the ability to locate the limb accurately in space, which generalizes broadly.
Afferent inputs to cortical fast-spiking interneurons organize pyramidal cell network oscillations at high-gamma frequencies (60–200 Hz)
Authors: Suffczynski Piotr , Crone Nathan E. , Franaszczuk Piotr J.
Published: September 2014

High-gamma activity, ranging in frequency between ∼60 Hz and 200 Hz, has been observed in local field potential, electrocorticography, EEG and magnetoencephalography signals during cortical activation, in a variety of functional brain systems. The origin of these signals is yet unknown. Using computational modeling, we show that a cortical network model receiving thalamic input generates high-gamma responses comparable to those observed in local field potential recorded in monkey somatosensory cortex during vibrotactile stimulation. These high-gamma oscillations appear to be mediated mostly by an excited population of inhibitory fast-spiking interneurons firing at high-gamma frequencies and pacing excitatory regular-spiking pyramidal cells, which fire at lower rates but in phase with the population rhythm. The physiological correlates of high-gamma activity, in this model of local cortical circuits, appear to be similar to those proposed for hippocampal ripples generated by subsets of interneurons that regulate the discharge of principal cells.
Framework of Resource Management for Intercloud Computing
Authors: Aazam Mohammad , Huh Eui-Nam
Published: September 2014

There has been a very rapid increase in digital media content, due to which media cloud is gaining importance. Cloud computing paradigm provides management of resources and helps create extended portfolio of services. Through cloud computing, not only are services managed more efficiently, but also service discovery is made possible. To handle rapid increase in the content, media cloud plays a very vital role. But it is not possible for standalone clouds to handle everything with the increasing user demands. For scalability and better service provisioning, at times, clouds have to communicate with other clouds and share their resources. This scenario is called Intercloud computing or cloud federation. The study on Intercloud computing is still in its start. Resource management is one of the key concerns to be addressed in Intercloud computing. Already done studies discuss this issue only in a trivial and simplistic way. In this study, we present a resource management model, keeping in view different types of services, different customer types, customer characteristic, pricing, and refunding. The presented framework was implemented using Java and NetBeans 8.0 and evaluated using CloudSim 3.0.3 toolkit. Presented results and their discussion validate our model and its efficiency.
Cognitive Restructuring and Graded Behavioural Exposure for Delusional Appraisals of Auditory Hallucinations and Comorbid Anxiety in Paranoid Schizophrenia
Authors: Mankiewicz Pawel D. , Turner Colin
Published: September 2014

The prevalence of diagnostic comorbidity between psychosis and anxiety disorders has been found to be considerable. Cognitive models of psychosis suggest that anxiety does not arise directly from positive symptoms of schizophrenia but rather from an individual interpretation of such experiences. In the United Kingdom, cognitive-behavioural therapy for psychosis (CBTp) has been recommended within clinical guidelines as a psychological treatment of choice for those diagnosed with schizophrenia. However, despite empirical evidence supporting CBTp, the treatment provision remains infrequent and not routinely available. This case describes a successful implementation of CBTp. Sixteen sessions were delivered to a 40-year-old male with diagnoses of paranoid schizophrenia and comorbid anxiety, focusing primarily on cognitive restructuring of paranoid appraisals of auditory hallucinations and behavioural experiments employed progressively via graded exposure to anxiety-inducing stimuli. Standardised measurements, behavioural frequency sampling, and subjective data indicated a considerable reduction in both paranoia and anxiety. Also, the client’s psychosocial functioning improved substantially. This report indicates that the treatment may help those with experiences of psychosis and comorbid anxiety reach a significant improvement in their quality of life and offers an encouraging and innovative perspective on direct engagement with the content of paranoia and voices at the onset of therapy.