bluuebunny/crossref_metadata_2025 huggingface dataset:
Binding Interactions between Soluble HIV Envelope Glycoproteins and Quaternary-Structure-Specific Monoclonal Antibodies PG9 and PG16
Authors: Davenport Thaddeus M. , Friend Della , Ellingson Katharine , Xu Hengyu , Caldwell Zachary , Sellhorn George , Kraft Zane , Strong Roland K. , Stamatatos Leonidas
Published: May 2011

PG9 and PG16 are antibodies isolated from a subject infected with HIV-1 and display broad anti-HIV neutralizing activities. They recognize overlapping epitopes, which are preferentially expressed on the membrane-anchored trimeric form of the HIV envelope glycoprotein (Env). PG9 and PG16 were reported not to bind to soluble mimetics of Env. The engineering of soluble Env proteins on which the PG9 and PG16 epitopes are optimally exposed will support efforts to elicit broad anti-HIV neutralizing antibodies by immunization. Here, we identified several soluble gp140 Env proteins that are recognized by PG9 and PG16, and we investigated the molecular details of those binding interactions. The IgG versions of PG9 and PG16 recognize the soluble trimeric gp140 form less efficiently than the corresponding monomeric gp140 form. In contrast, the Fab versions of PG9 and PG16 recognized the monomeric and trimeric gp140 forms with identical binding kinetics and with binding affinities similar to the high binding affinity of the anti-V3 antibody 447D to its epitope. Our data also indicate that, depending on the Env backbone, the interactions of PG9 and PG16 with gp140 may be facilitated by the presence of the gp41 ectodomain and are independent of the proper enzymatic cleavage of gp140 into gp120 and gp41. The identification of soluble Env proteins that express the PG9 and PG16 epitopes and the detailed characterization of the molecular interactions between these two antibodies and their ligands provide important and novel information that will assist in improving the engineering of future Env immunogens.
Canonical NF-κB Activation Is Essential for Epstein-Barr Virus Latent Membrane Protein 1 TES2/CTAR2 Gene Regulation
Authors: Gewurz Benjamin E. , Mar Jessica C. , Padi Megha , Zhao Bo , Shinners Nicholas P. , Takasaki Kaoru , Bedoya Edward , Zou James Y. , Cahir-Mcfarland Ellen , Quackenbush John , Kieff Elliott
Published: May 2011

Epstein-Barr virus (EBV) latent membrane protein 1 (LMP1) transforms rodent fibroblasts and is expressed in most EBV-associated malignancies. LMP1 (
t
ransformation
e
ffector
s
ite 2 [TES2]/C-terminal activation region 2 [CTAR2]) activates NF-κB, p38, Jun N-terminal protein kinase (JNK), extracellular signal-regulated kinase (ERK), and interferon regulatory factor 7 (IRF7) pathways. We have investigated LMP1 TES2 genome-wide RNA effects at 4 time points after LMP1 TES2 expression in HEK-293 cells. By using a false discovery rate (FDR) of <0.001 after correction for multiple hypotheses, LMP1 TES2 caused >2-fold changes in 1,916 mRNAs; 1,479 RNAs were upregulated and 437 were downregulated. In contrast to tumor necrosis factor alpha (TNF-α) stimulation, which transiently upregulates many target genes, LMP1 TES2 maintained most RNA effects through the time course, despite robust and sustained induction of negative feedback regulators, such as IκBα and A20. LMP1 TES2-regulated RNAs encode many NF-κB signaling proteins and secondary interacting proteins. Consequently, many LMP1 TES2-regulated RNAs encode proteins that form an extensive interactome. Gene set enrichment analyses found LMP1 TES2-upregulated genes to be significantly enriched for pathways in cancer, B- and T-cell receptor signaling, and Toll-like receptor signaling. Surprisingly, LMP1 TES2 and IκBα superrepressor coexpression decreased LMP1 TES2 RNA effects to only 5 RNAs, with FDRs of <0.001-fold and >2-fold changes. Thus, canonical NF-κB activation is critical for almost all LMP1 TES2 RNA effects in HEK-293 cells and a more significant therapeutic target than previously appreciated.
Identification and Expression Analysis of Herpes B Virus-Encoded Small RNAs
Authors: Amen Melanie A. , Griffiths Anthony
Published: May 2011

Herpes B virus (BV) naturally infects macaque monkeys and is genetically similar to herpes simplex virus (HSV). Zoonotic infection of humans can cause encephalitis and if untreated has a fatality rate of ∼80%. The frequent use of macaques in biomedical research emphasizes the need to understand the molecular basis of BV pathogenesis with a view toward improving safety for those working with macaques. MicroRNAs (miRNAs) are small noncoding RNAs that regulate the expression of mRNAs bearing complementary target sequences and are employed by viruses to control viral and host gene expression. Using deep sequencing and validation by expression in transfected cells, we identified 12 novel BV-encoded miRNAs expressed in lytically infected cells and 4 in latently infected trigeminal ganglia (TG). Using quantitative reverse transcription-PCR (RT-qPCR), we found that most of the miRNAs exhibited a high level of abundance throughout infection. Further analyses showed that some miRNAs could be generated from multiple transcripts with different kinetic classes, possibly explaining detection throughout infection. Interestingly, miRNAs were detected at early times in the absence of viral gene expression and were present in purified virions. In TG, despite similar amounts of viral DNA per ganglion, it was notable that the relative amount of each miRNA varied between ganglia. The majority of the miRNAs are encoded by the regions that exhibit the most sequence differences between BV and HSV. Additionally, there is no sequence conservation between BV- and HSV-encoded miRNAs, which may be important for the differences in the human diseases caused by BV and HSV.
Identification of Amino Acid Residues Important for Heparan Sulfate Proteoglycan Interaction within Variable Region 3 of the Feline Immunodeficiency Virus Surface Glycoprotein
Authors: Hu Qiong-Ying , Fink Elizabeth , Happer Meaghan , Elder John H.
Published: May 2011

Heparan sulfate proteoglycans (HSPGs) act as binding receptors or attachment factors for the viral envelope of many viruses, including strains of HIV and feline immunodeficiency virus (FIV). The FIV gp95 glycoprotein (SU) from laboratory-adapted strains (tissue culture adapted [TCA]) such as FIV-34TF10 can bind to HSPG, whereas SU from field strains (FS) such as FIV-PPR cannot. Previous studies indicate that SU-HSPG interactions occur within the V3 loop. We utilized a series of nested V3 peptides to further map the HSPG binding sites and found that both sides of the predicted V3 loop stem were critical for the binding but not the CXCR4 binding domain near the predicted tip of the V3 loop. Neutralization assays for TCA strain entry using the same set of V3 peptides showed that peptides targeting CXCR4 or HSPG binding sites can block infection, supporting the V3 loop as a critical neutralization target. Site-directed mutagenesis identified two highly conserved arginines, R379 and R389, on the N-terminal side of the V3 stem as critical for the contact between SU and HSPG. Residues K407, K409, K410, and K412 on the C-terminal side of the V3 stem form a second nonconserved domain necessary for HSPG binding, consistent with the observed specificity distinctions with FS FIV. Our findings discriminate structural determinants important for HSPG and CXCR4 binding by FIV SU and thus further define the importance of the V3 loop for virus entry and infection.
The Domain I-Domain III Linker Plays an Important Role in the Fusogenic Conformational Change of the Alphavirus Membrane Fusion Protein
Authors: Zheng Yan , Sánchez-San Martín Claudia , Qin Zhao-ling , Kielian Margaret
Published: May 2011

The alphavirus Semliki Forest virus (SFV) infects cells through a low-pH-dependent membrane fusion reaction mediated by the virus fusion protein E1. Acidic pH initiates a series of E1 conformational changes that culminate in membrane fusion and include dissociation of the E1/E2 heterodimer, insertion of the E1 fusion loop into the target membrane, and refolding of E1 to a stable trimeric hairpin conformation. A highly conserved histidine (H3) on the E1 protein was previously shown to promote low-pH-dependent E1 refolding. An SFV mutant with an alanine substitution at this position (H3A) has a lower pH threshold and reduced efficiency of virus fusion and E1 trimer formation than wild-type SFV. Here we addressed the mechanism by which H3 promotes E1 refolding and membrane fusion. We identified E1 mutations that rescue the H3A defect. These revertants implicated a network of interactions that connect the domain I-domain III (DI-DIII) linker region with the E1 core trimer, including H3. In support of the importance of these interactions, mutation of residues in the network resulted in more acidic pH thresholds and reduced efficiencies of membrane fusion.
In vitro
studies of truncated E1 proteins demonstrated that the DI-DIII linker was required for production of a stable E1 core trimer on target membranes. Together, our results suggest a critical and previously unidentified role for the DI-DIII linker region during the low-pH-dependent refolding of E1 that drives membrane fusion.
A Reassortment-Incompetent Live Attenuated Influenza Virus Vaccine for Protection against Pandemic Virus Strains
Authors: Hai Rong , García-Sastre Adolfo , Swayne David E. , Palese Peter
Published: May 2011

Although live-attenuated influenza vaccines (LAIV) are safe for use in protection against seasonal influenza strains, concerns regarding their potential to reassort with wild-type virus strains have been voiced. LAIVs have been demonstrated to induce enhanced mucosal and cell-mediated immunity better than inactivated vaccines while also requiring a smaller dose to achieve a protective immune response. To address the need for a reassortment-incompetent live influenza A virus vaccine, we have designed a chimeric virus that takes advantage of the fact that influenza A and B viruses do not reassort. Our novel vaccine prototype uses an attenuated influenza B virus that has been manipulated to express the ectodomain of the influenza A hemagglutinin protein, the major target for eliciting neutralizing antibodies. The hemagglutinin RNA segment is modified such that it contains influenza B packaging signals, and therefore it cannot be incorporated into a wild-type influenza A virus. We have applied our strategy to different influenza A virus subtypes and generated chimeric B/PR8 HA (H1), HK68 (H3), and VN (H5) viruses. All recombinant viruses were attenuated both
in vitro
and
in vivo
, and immunization with these recombinant viruses protected mice against lethal influenza A virus infection. Overall, our data indicate that the chimeric live-attenuated influenza B viruses expressing the modified influenza A hemagglutinin are effective LAIVs.
Absence of XMRV Retrovirus and Other Murine Leukemia Virus-Related Viruses in Patients with Chronic Fatigue Syndrome
Authors: Shin Clifford H. , Bateman Lucinda , Schlaberg Robert , Bunker Ashley M. , Leonard Christopher J. , Hughen Ronald W. , Light Alan R. , Light Kathleen C. , Singh Ila R.
Published: May 2011

Chronic fatigue syndrome (CFS) is a multisystem disorder characterized by prolonged and severe fatigue that is not relieved by rest. Attempts to treat CFS have been largely ineffective primarily because the etiology of the disorder is unknown. Recently, CFS has been associated with xenotropic murine leukemia virus-related virus (XMRV) as well as other murine leukemia virus (MLV)-related viruses, though not all studies have found these associations. We collected blood samples from 100 CFS patients and 200 self-reported healthy volunteers from the same geographical area. We analyzed these in a blind manner using molecular, serological, and viral replication assays. We also analyzed samples from patients in the original study that reported XMRV in CFS patients. We did not find XMRV or related MLVs either as viral sequences or infectious viruses, nor did we find antibodies to these viruses in any of the patient samples, including those from the original study. We show that at least some of the discrepancy with previous studies is due to the presence of trace amounts of mouse DNA in the
Taq
polymerase enzymes used in these previous studies. Our findings do not support an association between CFS and MLV-related viruses, including XMRV, and the off-label use of antiretrovirals for the treatment of CFS does not seem justified at present.
Heliothis zea
Nudivirus 1 Gene
hhi1
Induces Apoptosis Which Is Blocked by the
Hz-iap2
Gene and a Noncoding Gene,
pag1
Authors: Wu Yueh-Lung , Wu Carol P. , Liu Catherine Y. Y. , Lee Song-Tay , Lee Hsiao-Ping , Chao Yu-Chan
Published: May 2011

Heliothis zea
nudivirus 1 (
Hz
NV-1 or
Hz
-1 virus), previously regarded as a nonoccluded baculovirus, recently has been placed in the
Nudivirus
genus. This virus generates
Hz
NV-1 HindIII-I 1 (
hhi1
) and many other transcripts during productive viral infection; during latent viral infection, however, persistency-associated gene 1 (
pag1
) is the only gene expressed. In this report, we used transient expression assays to show that
hhi1
can trigger strong apoptosis in transfected cells, which can be blocked, at least partially, by the inhibitor of apoptosis genes
Autographa californica iap2 (Ac-iap2
) and
H. zea iap2
(
Hz-iap2)
. In addition to these two genes, unexpectedly,
pag1
, which encodes a noncoding RNA with no detectable protein product, was found to efficiently suppress
hhi1
-induced apoptosis. The assay of pro-
Sf
-caspase-1 processing by
hhi1
transfection did not detect the small P12 subunit at any of the time intervals tested, suggesting that
hhi1
of
Hz
NV-1 induces apoptosis through alternative caspase pathways.
Peptides Derived from a Distinct Region of GB Virus C Glycoprotein E2 Mediate Strain-Specific HIV-1 Entry Inhibition
Authors: Koedel Yvonne , Eissmann Kristin , Wend Holger , Fleckenstein Bernhard , Reil Heide
Published: May 2011

The nonpathogenic human GB virus C (GBV-C), a member of the
Flaviviridae
, is highly prevalent in individuals with HIV-1 infections or with parenteral and sexual risk factors. Long-term GBV-C viremia has been associated with better survival or improved diagnosis in several epidemiological studies. In a previous study we reported that the E2 glycoprotein of GBV-C interferes with HIV-1 entry
in vitro
. To address the question what region of the E2 protein is involved in suppression of HIV-1 replication, we performed an E2-derived peptide scanning and determined the HIV-inhibitory activity of each peptide in HIV replication assays. We demonstrate here that peptides representing the N-terminal part of the E2 protein from amino acids (aa) 29 to 72 are able to inhibit efficiently HIV-1 replication
in vitro
. In particular, the peptides P6-2 (representing the E2-region from aa 45 to 64) and P4762 (aa 37 to 64) showed the highest potency in HIV replication assays performed on TZM-bl cells with 50% inhibitory concentrations between 0.1 and 2 μM. However, primary HIV-1 isolates representing clades A to H showed a high variability in their sensitivity to E2 peptides. Pseudovirus inhibition assays revealed that the sensitivity is determined by the gp120/gp41 envelope proteins. Using HIV-1 BlaM-Vpr-based fusion assays, we demonstrate that the E2-derived peptides prevent HIV-1 binding or fusion, presumably via interaction with the HIV-1 particle. Together, these findings reveal a new mechanism of viral interference, suggesting that the envelope protein E2 of GBV-C target directly HIV-1 particles to avoid entry of these virions.
Role of CD4
+
and CD8
+
T-Cell Responses against JC Virus in the Outcome of Patients with Progressive Multifocal Leukoencephalopathy (PML) and PML with Immune Reconstitution Inflammatory Syndrome
Authors: Gheuens Sarah , Bord Evelyn , Kesari Santosh , Simpson David M. , Gandhi Rajesh T. , Clifford David B. , Berger Joseph R. , Ngo Long , Koralnik Igor J.
Published: May 2011

Progressive multifocal leukoencephalopathy (PML) is a severe demyelinating disease of the brain caused by JC virus (JCV). To assess the role of CD4
+
and CD8
+
T-cells against JCV in the clinical outcome of PML and PML in the setting of immune reconstitution inflammatory syndrome (IRIS), we tested gamma interferon (IFN-γ) response by enzyme-linked immunosorbent spot (ELISpot) and intracellular cytokine staining (ICS) in 117 subjects, including 66 PML patients with different clinical outcomes. Both assays were concordant and demonstrated that the cellular immune response against JCV is associated with better clinical outcome. PML survivors had an early CD8
+
T-cell response more frequently than PML progressors (100% versus 27.3%;
P
= 0.001), while only a trend was observed for the early CD4
+
T-cell response between these two groups (80% versus 45.5%;
P
= 0.18). Although IRIS itself was more frequent in the PML survivor group, there was no difference in IFN-γ-producing CD4
+
and CD8
+
T-cells between IRIS and non-IRIS PML patients, suggesting that T-cells expressing other cytokines likely have a role in the immunopathogenesis of IRIS. ELISpot and ICS assays are useful prognostic markers of PML evolution and may help in the clinical management of these patients.
Injection treatments for patellar tendinopathy
Authors: van Ark Mathijs , Zwerver Johannes , van den Akker-Scheek Inge
Published: May 2011

Objective

Injection treatments are increasingly used as treatment for patellar tendinopathy. The aim of this systematic review is to describe the different injection treatments, their rationales and the effectiveness of treating patellar tendinopathy.

Methods

A computerised search of the Medline, Embase, CINAHL and Web of Knowledge databases was conducted on 1 May 2010 to identify studies on injection treatments for patellar tendinopathy.

Results

11 articles on seven different injection treatments (dry needling, autologous blood, high-volume, platelet-rich plasma, sclerosis, steroids and aprotinin injections) were found: 4 randomised controlled trials (RCTs), 1 non-RCT, 4 prospective cohort studies and 2 retrospective cohort studies. All studies reported positive results. The Delphi scores of the four RCTs ranged from 5 to 8 out of 9. Different and sometimes contradictory rationales were used for the injection treatments.

Conclusion

All seven different injection treatments seem promising for treating patellar tendinopathy. Unlike the other injection treatments, steroid treatment often shows a relapse of symptoms in the long term. Results should be interpreted with caution as the number of studies is low, few high-quality studies have been conducted and the studies are hard to compare due to different methodology. More high-quality studies using the same cross-cultural reliable and valid outcome measure are needed, as well as further research into the pathophysiology. Finally, some implications are provided for clinicians who want to use injection treatments as a part of their treatment for patellar tendinopathy, distinguishing between reactive and degenerative phase of patellar tendinopathy.
SYNTHESIS AND MICROWAVE DIELECTRIC PROPERTIES OF Li2MgSiO4 CERAMICS PREPARED USING CITRATE GEL ROUTE
Authors: GEORGE S. , SAJITH V. K. , SEBASTIAN M. T. , RAMAN S. , MOHANAN P.
Published: May 2011

The comparison of the low temperature sintering and the microwave dielectric properties of Li2MgSiO4 (LMS) ceramics prepared by citrate gel (CG) route and solid state (SS) ceramic route are discussed in this paper. The LMS prepared using CG route sintered at 1175°C/2 h has εr = 5.3 and tan δ = 1 × 10−3 at 9 GHz. The sintering temperature of LMS is lowered to 950°C with the addition of 5 wt% lithium magnesium zinc borosilicate glass and has εr = 5.6 and tan δ = 2 × 10-3 at 9 GHz. The amount of glass required to lower the sintering temperature of ceramics prepared using CG are slightly higher than that of SS ceramic route. The LMS ceramics prepared using SS ceramic route shows excellent microwave dielectric properties with low sintering temperature compared to CG route.
EVIDENCES OF A STRUCTURAL PHASE TRANSITION IN THE NEW Pb(ZryTi1 - y)O3 MODIFIED TELLURITE GLASS-CERAMIC COMPOSITE
Authors: GUERRA J. D. S. , HATHENHER C. R.
Published: May 2011

The physical properties of the new TeO 2 – B2O3 – PbO2 (TBP)-based glass system, obtained from the usual melt-quench method, have been investigated taking into account the influence of the Pb ( Zr y Ti 1 - y) O 3 (PZT) ferroelectric system. A crystalline-like structure, which characterizes a glass-ceramic-like state, promoted by the ferroelectric phase, has been revealed from the X-ray diffraction results for the sample with higher PZT concentration. On the other hand, results on the dielectric response revealed noticeable dielectric anomalies, which until now have not been reported. In fact, the dielectric and ferroelectric properties suggest the existence of a structural phase transition induced by the PZT crystalline phase, which indeed have been related to the ferroelectric polar-phase regions embedded into the glass matrix.
Mechanosignaling to the Cell Nucleus and Gene Regulation
Authors: Shivashankar G.V.
Published: May 2011

Cells integrate physicochemical signals on the nanoscale from the local microenvironment, resulting in altered functional nuclear landscape and gene expression. These alterations regulate diverse biological processes including stem cell differentiation, establishing robust developmental genetic programs and cellular homeostatic control systems. The mechanisms by which these signals are integrated into the 3D spatiotemporal organization of the cell nucleus to elicit differential gene expression programs are poorly understood. In this review I analyze our current understanding of mechanosignal transduction mechanisms to the cell nucleus to induce differential gene regulation. A description of both physical and chemical coupling, resulting in a prestressed nuclear organization, is emphasized. I also highlight the importance of spatial dimension in chromosome assembly, as well as the temporal filtering and stochastic processes at gene promoters that may be important in understanding the biophysical design principles underlying mechanoregulation of gene transcription.
Nanoporous Gold Catalyst for Direct Ammonia Borane Fuel Cells
Authors: Nagle Lorraine C. , Rohan James F.
Published: May 2011

Nanoporous gold (NPG) electrodes were fabricated in film and wire array formats by selectively dealloying Ag from Au0.18Ag0.82. The ammonia borane (AB) oxidation reaction was studied by cyclic voltammetry at the NPG electrodes. The onset potential for the oxidation at NPG in a wire array format shifted to more negative potentials than that observed at a Au disc and higher currents were realised. An onset potential of −1.30 V vs. SCE was recorded which is 0.28 V lower than that at a Au disc. The oxidation current for 20 mM AB in 1 M NaOH increased from 2.65 mA cm−2 at a Au disc to 13.1 mA cm−2 at a NPG wire array. NPG is a viable candidate as an anode catalyst for a direct ammonia borane fuel cell.
Graphite Disk Lanthanum(III)-Selective Electrode Based on Benzo-15-crown-5
Authors: Arbab Zavar Mohammad Hossein , Heydari Somayeh , Rounaghi Gholam Hossein , Ashraf Narges
Published: May 2011

In this study, construction of a new lanthanum selective disk electrode based on benzo-15-crown-5 (B15C5) as a neutral carrier has been described. The electrode has been composed of 2.5 mg of Benzo-15-crown5 as an ionophore, 7 mg of oleic acid (OA) as an additive, 60.5 mg of ortho-nitrophenyloctyl ether (NPOE) as a plasticizer, and 30 mg of polyvinyl chloride (PVC) as the membrane supporting matrix. The electrode shows a linear dynamic response in the concentration range of 5 × 10−7 to 1 × 10−2 M with a Nernstian slope of 19.5 mV per decade and a detection limit of 8.74 × 10−7 M. It has a response time of <15 s and can be used for at least 5 months without any significant divergence in potentials. The selectivity coefficients for mono, di, and trivalent cations indicate a good selectivity for La(III) ions over a large number of interfering cations. It could be used in a pH range of 3.0−6.0. The proposed electrode was applied as an indicator electrode in potentiometric titration of fluoride ion and also used for determination of F− ion in mouthwash solution, tap water and toothpaste samples.
Vanilloid, purinergic, and CCK receptors activate glutamate release on single neurons of the nucleus tractus solitarius centralis
Authors: Browning Kirsteen N. , Wan ShuXia , Baptista Vander , Travagli R. Alberto
Published: May 2011

Baroreceptor inputs to nucleus of the tractus solitarius medialis (mNTS) neurons can be differentiated, among other features, by their response to vanilloid or purinergic agonists, active only on C- or A-fibers, respectively. A major aim of this study was to examine whether neurons of NTS centralis (cNTS), a subnucleus dominated by esophageal inputs, exhibit a similar dichotomy. Since it has been suggested that cholecystokinin (CCK), exerts its gastrointestinal (GI)-related effects via paracrine activation of vagal afferent C-fibers, we tested whether CCK-sensitive fibers impinging upon cNTS neurons are responsive to vanilloid but not purinergic agonists. Using whole cell patch-clamp recordings from cNTS, we recorded miniature excitatory postsynaptic currents (mEPSCs) to test the effects of the vanilloid agonist capsaicin, the purinergic agonist α,β-methylene-ATP (α,β-Met-ATP), and/or CCK-octapeptide (CCK-8s). α,β-Met-ATP, capsaicin; and CCK-8s increased EPSC frequency in 37, 71, and 46% of cNTS neurons, respectively. Approximately 30% of cNTS neurons were responsive to both CCK-8s and α,β-Met-ATP, to CCK-8s and capsaicin, or to α,β-Met-ATP and capsaicin, while 32% of neurons were responsive to all three agonists. All neurons responding to either α,β-Met-ATP or CCK-8s were also responsive to capsaicin. Perivagal capsaicin, which is supposed to induce a selective degeneration of C-fibers, decreased the number of cNTS neurons responding to capsaicin or CCK-8s but not those responding to α,β-Met-ATP. In summary, GI inputs to cNTS neurons cannot be distinguished on the basis of their selective responses to α,β-Met-ATP or capsaicin. Our data also indicate that CCK-8s increases glutamate release from purinergic and vanilloid responsive fibers impinging on cNTS neurons.
Chronic intermittent hypoxia increases blood pressure and expression of FosB/ΔFosB in central autonomic regions
Authors: Knight W. David , Little Joel T. , Carreno Flavia R. , Toney Glenn M. , Mifflin Steven W. , Cunningham J. Thomas
Published: May 2011

Chronic intermittent hypoxia (CIH) models repetitive bouts of arterial hypoxemia that occur in humans suffering from obstructive sleep apnea. CIH has been linked to persistent activation of arterial chemoreceptors and the renin-angiotensin system, which have been linked to chronic elevations of sympathetic nerve activity (SNA) and mean arterial pressure (MAP). Because Fos and FosB are transcription factors involved in activator protein (AP)-1 driven central nervous system neuronal adaptations, this study determined if CIH causes increased Fos or FosB staining in brain regions that regulate SNA and autonomic function. Male Sprague Dawley rats were instrumented with telemetry transmitters for continuous recording of MAP and heart rate (HR). Rats were exposed to continuous normoxia (CON) or to CIH for 8 h/day for 7 days. CIH increased MAP by 7–10 mmHg without persistently affecting HR. A separate group of rats was killed 1 day after 7 days of CIH for immunohistochemistry. CIH did not increase Fos staining in any brain region examined. Staining for FosB/ΔFosB was increased in the organum vasculosum of the lamina terminalis (CON: 9 ± 1; CIH: 34 ± 3 cells/section), subfornical organ (CON: 7 ± 2; CIH: 31 ± 3), median preoptic nucleus (CON 15 ± 1; CIH: 38 ± 3), nucleus of the solitary tract (CON: 9 ± 2; CIH: 28 ± 4), A5 (CON: 3 ± 1; CIH: 10 ± 1), and rostral ventrolateral medulla (CON: 5 ± 1; CIH: 17 ± 2). In the paraventricular nucleus, FosB/ΔFosB staining was located mainly in the dorsal and medial parvocellular subnuclei. CIH did not increase FosB/ΔFosB staining in caudal ventrolateral medulla or supraoptic nucleus. These data indicate that CIH induces an increase in FosB/ΔFosB in autonomic nuclei and suggest that AP-1 transcriptional regulation may contribute to stable adaptive changes that support chronically elevated SNA.
Statins reverse renal inflammation and endothelial dysfunction induced by chronic high salt intake
Authors: Fiore M. C. , Jimenez P. M. , Cremonezzi D. , Juncos L. I. , García N. H.
Published: May 2011

High salt intake (HS) is a risk factor for cardiovascular and kidney disease. Indeed, HS may promote blood-pressure-independent tissue injury via inflammatory factors. The lipid-lowering 3-hydroxy 3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors exert beneficial lipid-independent effects, reducing the expression and synthesis of inflammatory factors. We hypothesized that HS impairs kidney structure and function in the absence of hypertension, and these changes are reversed by atorvastatin. Four groups of rats were treated for 6 wk in metabolic cages with their diets: normal salt (NS); HS, NS plus atorvastatin and HS plus atorvastatin. We measured basal and final body weight, urinary sodium and protein excretion (UProtV), and systolic blood pressure (SBP). At the end of the experimental period, cholesterolemia, creatinine clearance, renal vascular reactivity, glomerular volume, cortical and glomerular endothelial nitric oxide synthase (eNOS), and transforming growth factor (TGF)-β1 expression were measured. We found no differences in SBP, body weight, and cholesterolemia. HS rats had increased creatinine clearence, UProtV, and glomerular volume at the end of the study. Acetylcholine-induced vasodilatation decreased by 40.4% in HS rats ( P < 0.05). HS decreased cortical and glomerular eNOS and caused mild glomerular sclerosis, interstitial mononuclear cell infiltration, and increased cortical expression of TGF-β1. All of these salt-induced changes were reversed by atorvastatin. We conclude that long-term HS induces inflammatory and hemodynamic changes in the kidney that are independent of SBP. Atorvastatin corrected all, suggesting that the nitric oxide-oxidative stress balance plays a significant role in the earlier stages of salt induced kidney damage.
Regulation of Kir4.1 and AQP4 expression and stability at the basolateral domain of epithelial MDCK cells by the extracellular matrix
Authors: Tham Daniel Kai Long , Moukhles Hakima
Published: May 2011

The proper targeting of ion channels to specialized domains is crucial for cell function. Kir4.1, the inwardly rectifying potassium channel, and aquaporin-4 (AQP4), the type 4 water-permeable channel, are localized at the basolateral domain of polarized epithelial cells; however, the mechanisms involved in their localization have yet to be determined. In this study, we investigated the role of the extracellular matrix in the localization of these channels in polarized Madin-Darby canine kidney (MDCK) cells. MDCK cells expressing green fluorescent protein-Kir4.1 or -AQP4 were cultured on laminin-1 or fibronectin and examined by confocal microscopy and cell surface biotinylation to assess plasma membrane expression of Kir4.1 and AQP4. Our data show that laminin-1 and fibronectin induce a significant increase in cell surface expression of both channels at the basolateral domain. Using fluorescence recovery after photobleaching, we demonstrate that laminin-1 and fibronectin reduce the diffusion rates of these channels. Finally, we show that the laminin receptor dystroglycan is important for cell surface expression of Kir4.1 but not AQP4. However, laminin-1 increases cell surface expression of both channels in cells deficient for dystroglycan, indicating that other receptors are involved. Indeed, RGD-containing peptides, which inhibit fibronectin binding to certain integrins, prevent the fibronectin-induced increase in Kir4.1 and AQP4 cell surface expression and reverse the laminin- and fibronectin-induced reduction in both channels' diffusion rates. Similarly, the αvβ3-integrin function-blocking antibody alters the reduction of AQP4 diffusion rates induced by both laminin and fibronectin, suggesting that αvβ3-integrin plays a role in the stabilization of APQ4 at the basolateral domain of epithelial cells.
Renal inflammation and elevated blood pressure in a mouse model of reduced β-ENaC
Authors: Drummond Heather A. , Grifoni Samira C. , Abu-Zaid Ahmed , Gousset Monette , Chiposi Rumbidayzi , Barnard John M. , Murphey Beau , Stec David E.
Published: May 2011

Previous studies suggest β-epithelial Na+channel protein (β-ENaC) may mediate myogenic constriction, a mechanism of blood flow autoregulation. A recent study demonstrated that mice with reduced levels of β-ENaC (β-ENaC m/m) have delayed correction of whole kidney blood flow responses, suggesting defective myogenic autoregulatory capacity. Reduced renal autoregulatory capacity is linked to renal inflammation, injury, and hypertension. However, it is unknown whether β-ENaC m/m mice have any complications associated with reductions in autoregulatory capacity such as renal inflammation, injury, or hypertension. To determine whether the previously observed altered autoregulatory control was associated with indicators of renal injury, we evaluated β-ENaC m/m mice for signs of renal inflammation and tissue remodeling using marker expression. We found that inflammatory and remodeling markers, such as IL-1β, IL-6, TNF-α, collagen III and transforming growth factor-β, were significantly upregulated in β-ENaC m/m mice. To determine whether renal changes were associated with changes in long-term control of blood pressure, we used radiotelemetry and found that 5-day mean arterial blood pressure (MAP) was significantly elevated in β-ENaC m/m (120 ± 3 vs. 105 ± 2 mmHg, P = 0.016). Our findings suggest loss of β-ENaC is associated with early signs of renal injury and increased MAP.
Changes in the neural control of a complex motor sequence during learning
Authors: Ölveczky Bence P. , Otchy Timothy M. , Goldberg Jesse H. , Aronov Dmitriy , Fee Michale S.
Published: May 2011

The acquisition of complex motor sequences often proceeds through trial-and-error learning, requiring the deliberate exploration of motor actions and the concomitant evaluation of the resulting performance. Songbirds learn their song in this manner, producing highly variable vocalizations as juveniles. As the song improves, vocal variability is gradually reduced until it is all but eliminated in adult birds. In the present study we examine how the motor program underlying such a complex motor behavior evolves during learning by recording from the robust nucleus of the arcopallium (RA), a motor cortex analog brain region. In young birds, neurons in RA exhibited highly variable firing patterns that throughout development became more precise, sparse, and bursty. We further explored how the developing motor program in RA is shaped by its two main inputs: LMAN, the output nucleus of a basal ganglia-forebrain circuit, and HVC, a premotor nucleus. Pharmacological inactivation of LMAN during singing made the song-aligned firing patterns of RA neurons adultlike in their stereotypy without dramatically affecting the spike statistics or the overall firing patterns. Removing the input from HVC, on the other hand, resulted in a complete loss of stereotypy of both the song and the underlying motor program. Thus our results show that a basal ganglia-forebrain circuit drives motor exploration required for trial-and-error learning by adding variability to the developing motor program. As learning proceeds and the motor circuits mature, the relative contribution of LMAN is reduced, allowing the premotor input from HVC to drive an increasingly stereotyped song.
The effect of TMS on visual motion sensitivity: an increase in neural noise or a decrease in signal strength?
Authors: Ruzzoli Manuela , Abrahamyan Arman , Clifford Colin W. G. , Marzi Carlo A. , Miniussi Carlo , Harris Justin A.
Published: May 2011

The underlying mechanisms of action of transcranial magnetic stimulation (TMS) are still a matter of debate. TMS may impair a subject's performance by increasing neural noise, suppressing the neural signal, or both. Here, we delivered a single pulse of TMS (spTMS) to V5/MT during a motion direction discrimination task while concurrently manipulating the level of noise in the motion stimulus. Our results indicate that spTMS essentially acts by suppressing the strength of the relevant visual signal. We suggest that TMS may induce a pattern of neural activity that complements the ongoing activation elicited by the sensory signal in a manner that partially impoverishes that signal.
Locomotor adaptations and aftereffects to resistance during walking in individuals with spinal cord injury
Authors: Houldin Adina , Luttin Kathryn , Lam Tania
Published: May 2011

Muscle activity during the swing phase of walking is influenced by proprioceptive feedback pathways. Previous studies have shown that feedback and anticipatory motor commands contribute to locomotor adaptive strategies to prolonged exposure to a resistance against leg movements during walking. The purpose of this study was to determine whether people with motor-incomplete spinal cord injuries (SCI) modulate flexor muscle activity in response to different levels of resistance in a similar way as uninjured controls. A second purpose was to determine whether people with motor-incomplete SCI have the capacity to form anticipatory motor commands following exposure to resistance. Subjects walked on a treadmill with the Lokomat robotic gait orthosis. The Lokomat applied different levels of a velocity-dependent resistance, normalized to each subject's maximum voluntary contraction of the hip flexors. Each condition consisted of 20 steps against resistance followed by 20 steps without. Electromyography and kinematics of the lower limb were recorded. Although both groups responded to the resistance with an overall increase in rectus femoris activity during swing, the SCI group showed weak modulation of muscle activity to different levels of resistance. Following removal of the resistance, both groups showed aftereffects, but they were manifested differently. Controls responded to the removal of resistance with a high step, whereas the SCI subjects exhibited increased step length. The size of the aftereffect was related to the amount of added resistance. In addition, the SCI group showed a negative relationship between the size of the aftereffect and locomotor function.
Task- and time-dependent modulation of Ia presynaptic inhibition during fatiguing contractions performed by humans
Authors: Baudry Stéphane , Maerz Adam H. , Gould Jeffrey R. , Enoka Roger M.
Published: May 2011

Presynaptic modulation of Ia afferents converging onto the motor neuron pool of the extensor carpi radialis (ECR) was compared during contractions (20% of maximal force) sustained to failure as subjects controlled either the angular position of the wrist while supporting an inertial load (position task) or exerted an equivalent force against a rigid restraint (force task). Test Hoffmann (H) reflexes were evoked in the ECR by stimulating the radial nerve above the elbow. Conditioned H reflexes were obtained by stimulating either the median nerve above the elbow or at the wrist (palmar branch) to assess presynaptic inhibition of homonymous (D1 inhibition) and heteronymous Ia afferents (heteronymous Ia facilitation), respectively. The position task was briefer than the force task ( P = 0.001), although the maximal voluntary force and electromyograph for ECR declined similarly at failure for both tasks. Changes in the amplitude of the conditioned H reflex were positively correlated between the two conditioning methods ( P = 0.02) and differed between the two tasks ( P < 0.05). The amplitude of the conditioned H reflex during the position task first increased (129 ± 20.5% of the initial value, P < 0.001) before returning to its initial value ( P = 0.22), whereas it increased progressively during the force task to reach 122 ± 17.4% of the initial value at failure ( P < 0.001). Moreover, changes in conditioned H reflexes were associated with the time to task failure and force fluctuations. The results suggest a task- and time-dependent modulation of presynaptic inhibition of Ia afferents during fatiguing contractions.
Hepatoprotective Effects of Orthosiphon stamineus Extract on Thioacetamide‐Induced Liver Cirrhosis in Rats
Authors: Alshawsh Mohammed A. , Abdulla Mahmood Ameen , Ismail Salmah , Amin Zahra A.
Published: May 2011

Orthosiphon stamineus as medicinal plant is commonly used in Malaysia for treatment of hepatitis and jaundice; in this study, the ethanol extracts were applied to evaluate the hepatoprotective effects in a thioacetamide‐induced hepatotoxic model in Sprague Dawley rats. Five groups of adult rats were arranged as follows: Group 1 (normal control group), Group 2 Thioacetamide (TAA) as positive control (hepatotoxic group), Group 3 Silymarin as a well‐known standard drug (hepatoprotective group), and Groups 4 and 5 as high and low dose (treatment groups). After 60‐day treatment, all rats were sacrificed. The hepatotoxic group showed a coarse granulation on the liver surface when compared to the smooth aspect observed on the liver surface of the other groups. Histopathological study confirmed the result; moreover, there was a significant increase in serum liver biochemical parameters (ALT, AST, ALP, and Bilirubin) and the level of liver Malondialdehyde (MDA), accompanied by a significant decrease in the level of total protein and Albumin in the TAA control group when compared with that of the normal group. The high‐dose treatment group (200 mg/kg) significantly restored the elevated liver function enzymes near to normal. This study revealed that 200 mg/kg extracts of O. stamineus exerted a hepatoprotective effect.
A Clinical Study of the Effectiveness of Two Different 10% Carbamide Peroxide Bleaching Products: A 6-Month Followup
Authors: Grobler S. R. , Majeed A. , Hayward R. , Rossouw R. J. , Moola M. H. , Kotze T. J. van W.
Published: May 2011

The purpose of this study was to evaluate the efficacy of two different 10% carbamide peroxide bleaching products just after treatment and after a 6-month follow-up period.Methods. Two 10% carbamide peroxide products (Opalescence PF and Nite White ACP) were applied nightly for 14 days, according to the manufacturers' instructions. The color of teeth 11 and 21 of thirty-four subjects having A2 or darker teeth were measured with a spectrophotometer (L∗;a∗;b∗) before treatment, just after treatment (14 days) and after 6 months.Results and Conclusions. Both products produced significant whitening of teeth with total color change (ΔEab∗) of approximately 5.20 units. There was a significant improvement in all 3 color coordinates (L*,a*, andb∗) for up to 6 months postbleaching (P<.05). Nite White showed a higher degree of relapse (27%) than Opalescence (18%) over the 6-month period. It is suggested that rebleaching after 6 months is not necessary.
A Case of Unresectable Rectal Necrosis
Authors: Nassif Mohammed , Ameer Ahmed , Meterissian Sarkis H. , Meguerditchian Ari-Nareg
Published: May 2011

Introduction. Necrosis of the rectum is an uncommon finding due to abundant collateral vasculature. Its management remains challenging, without clear consensus in the literature.Case Report. We describe a case of a 53-year-old woman with multiple medical comorbidities that presented in septic shock and hematochezia. Colonoscopy revealed ischemic colitis. Conservative management was instituted. At two weeks, she presented evidence of peritonitis. Exploratory laparotomy revealed extensive necrosis of the left colon and rectum. Due to dense inflammation, resection was deemed unsafe. Therefore, a transverse ostomy with mucosal fistula was preformed. Multiple drains were left in place. The patient healed uneventfully.Conclusion. This case illustrates that, if extensive dissection of the distal colon and rectum is unsafe due to the patient's critical condition or technical feasibility, then a diverting ostomy of the proximal viable bowel along with a mucus fistula and good drainage of the abdomen represents an acceptable alternative.
A Novel Control Method for Integer Orders Chaos Systems via Fractional‐Order Derivative
Authors: Zhou Ping , Kuang Fei
Published: May 2011

A fractional‐order control method is obtained to stabilize the point in chaos attractor of integer orders chaos systems. The control law has simple structure and is designed easily. Two examples are also given to illustrate the effectiveness of the theoretical result.
In VitroandEx VivoEvaluation of Smart Infra-Red Fluorescent Caspase-3 Probes for Molecular Imaging of Cardiovascular Apoptosis
Authors: Debunne Manuelle , Portal Christophe , Delest Bruno , Brakenhielm Ebba , Lallemand Françoise , Henry Jean-Paul , Ligeret Heidi , Noack Pauline , Massonneau Marc , Romieu Anthony , Renard Pierre-Yves , Thuillez Christian , Richard Vincent
Published: May 2011

Purpose. The aim of this paper is to develop new optical bioprobes for the imaging of apoptosis.Procedure. We developed quenched near-infrared probes which become fluorescent upon cleavage by caspase-3, the key regulatory enzyme of apoptosis.Results. Probes were shown to be selectively cleaved by recombinant caspase-3. Apoptosis of cultured endothelial cells was associated with an increased fluorescent signal for the cleaved probes, which colocalized with caspase-3 and was reduced by the addition of a caspase-3 inhibitor. Flow cytometry demonstrated a similar profile between the cleaved probes and annexin V.Ex vivoexperiments showed that sections of hearts obtained from mice treated with the proapoptotic drug doxorubicin displayed an increase in the fluorescent signal for the cleaved probes, which was reduced by a caspase-3 inhibitor.Conclusion. We demonstrated the capacity of these novel probes to detect apoptosis by optical imagingin vitroandex vivo.
An Environmental Friendly Procedure for Photometric Determination of Hypochlorite in Tap Water Employing a Miniaturized Multicommuted Flow Analysis Setup
Authors: Borges Sivanildo S. , Reis Boaventura F.
Published: May 2011

A photometric procedure for the determination ofClO-in tap water employing a miniaturized multicommuted flow analysis setup and an LED-based photometer is described. The analytical procedure was implemented using leucocrystal violet (LCV; 4,4′,4′′-methylidynetris (N,N-dimethylaniline), C25H31N3) as a chromogenic reagent. Solenoid micropumps employed for solutions propelling were assembled together with the photometer in order to compose a compact unit of small dimensions. After control variables optimization, the system was applied for the determination ofClO-in samples of tap water, and aiming accuracy assessment samples were also analyzed using an independent method. Applying the pairedt-test between results obtained using both methods, no significant difference at the 95% confidence level was observed. Other useful features include low reagent consumption, 2.4 μg of LCV per determination, a linear response ranging from 0.02 up to 2.0 mg L−1  ClO-, a relative standard deviation of 1.0% (n=11) for samples containing 0.2 mg L−1  ClO-, a detection limit of 6.0 μg L−1  ClO-, a sampling throughput of 84 determinations per hour, and a waste generation of 432 μL per determination.