bluuebunny/crossref_metadata_2025 huggingface dataset:
Outbreak of Human Metapneumovirus Detected by Use of the Vero E6 Cell Line in Isolates Collected in Yamagata, Japan, in 2004 and 2005
Authors: Abiko C. , Mizuta K. , Itagaki T. , Katsushima N. , Ito S. , Matsuzaki Y. , Okamoto M. , Nishimura H. , Aoki Y. , Murata T. , Hoshina H. , Hongo S. , Ootani K.
Published: April 2007

A number of epidemiological studies have shown human metapneumovirus (hMPV) to be one of the most important viral agents associated with acute respiratory infections in humans. However, due to the difficulty in growing the virus, all epidemiological studies of hMPV infection have been performed on the basis of the molecular method. Thus, the development of a cell line suitable for the isolation of hMPV from clinical specimens is a crucial step for further research. Using the Vero E6 cell line, which could be stably maintained for 1 month without passage or medium change, we succeeded in isolating 79 strains from 4,112 specimens obtained in Yamagata, Japan, in 2004 and 2005. The total isolation rate was 1.9% (79/4,112). The monthly distribution revealed that hMPV infections occurred between February and April in 2004 and throughout most of the year in 2005. Phylogenetic analysis indicated that subgenogroup B2 was predominant in 2004, whereas three subgenogroups, A2, B1, and B2, had cocirculated in 2005. Although multiple subgenogroups cocirculated in 2005, each individual subgenogroup strain was found to predominate at specific sites. An infectivity assay of hMPV strains also indicated that the infection efficiency in Vero E6 cells was better than that in LLC-MK2 cells. Finally, we found that Vero E6 cells are useful for the isolation of hMPVs and that this utility might aid further research into hMPVs beyond the epidemiological data shown in this study.
A Cluster of
Legionella
-Associated Pneumonia Cases in a Population of Military Recruits
Authors: McDonough Erin A. , Metzgar David , Hansen Christian J. , Myers Christopher A. , Russell Kevin L.
Published: April 2007

A
Legionella
cluster was identified through retrospective PCR analysis of 240 throat swab samples from X-ray-confirmed pneumonia cases. These were identified among young and otherwise healthy U.S. military recruits during population-based surveillance for pneumonia pathogens. Results were confirmed by sequence analysis. Cases clustered tightly, suggesting a local environmental etiology.
In Vitro Analysis of Transneuronal Spread of an Alphaherpesvirus Infection in Peripheral Nervous System Neurons
Authors: Feierbach B. , Bisher M. , Goodhouse J. , Enquist L. W.
Published: April 2007

The neurotropic alphaherpesviruses invade and spread in the nervous system in a directional manner between synaptically connected neurons. Until now, this property has been studied only in living animals and has not been accessible to in vitro analysis. In this study, we describe an in vitro system in which cultured peripheral nervous system neurons are separated from their neuron targets by an isolator chamber ring. Using pseudorabies virus (PRV), an alphaherpesvirus capable of transneuronal spread in neural circuits of many animals, we have recapitulated in vitro all known genetic requirements for retrograde and anterograde transneuronal spread as determined previously in vivo. We show that in vitro transneuronal spread requires intact axons and the presence of the viral proteins gE, gI, and Us9. We also show that transneuronal spread is dependent on the viral glycoprotein gB, which is required for membrane fusion, but not on gD, which is required for extracellular spread. We demonstrate ultrastructural differences between anterograde- and retrograde-traveling virions. Finally, we show live imaging of dynamic fluorescent virion components in axons and postsynaptic target neurons.
Marek's Disease Virus Type 2 (MDV-2)-Encoded MicroRNAs Show No Sequence Conservation with Those Encoded by MDV-1
Authors: Yao Yongxiu , Zhao Yuguang , Xu Hongtao , Smith Lorraine P. , Lawrie Charles H. , Sewer Alain , Zavolan Mihaela , Nair Venugopal
Published: April 2007

MicroRNAs (miRNAs) are increasingly being recognized as major regulators of gene expression in many organisms, including viruses. Among viruses, members of the familyHerpesviridaeaccount for the majority of the currently known virus-encoded miRNAs. The highly oncogenic Marek's disease virus type 1 (MDV-1), an avian herpesvirus, has recently been shown to encode eight miRNAs clustered in the MEQ and LAT regions of the viral genome. The genusMardivirus, to which MDV-1 belongs, also includes the nononcogenic but antigenically related MDV-2. As MDV-1 and MDV-2 are evolutionarily very close, we sought to determine if MDV-2 also encodes miRNAs. For this, we cloned, sequenced, and analyzed a library of small RNAs from the lymphoblastoid cell line MSB-1, previously shown to be coinfected with both MDV-1 and MDV-2. Among the 5,099 small RNA sequences determined from the library, we identified 17 novel MDV-2-specific miRNAs. Out of these, 16 were clustered in a 4.2-kb long repeat region that encodes R-LORF2 to R-LORF5. The single miRNA outside the cluster was located in the short repeat region, within the C-terminal region of the ICP4 homolog. The expression of these miRNAs in MSB-1 cells and infected chicken embryo fibroblasts was further confirmed by Northern blotting analysis. The identification of miRNA clusters within the repeat regions of MDV-2 demonstrates conservation of the relative genomic positions of miRNA clusters in MDV-1 and MDV-2, despite the lack of sequence homology among the miRNAs of the two viruses. The identification of these novel miRNAs adds to the growing list of virus-encoded miRNAs.
Essential Role of Dengue Virus Envelope Protein N Glycosylation at Asparagine-67 during Viral Propagation
Authors: Mondotte Juan A. , Lozach Pierre-Yves , Amara Ali , Gamarnik Andrea V.
Published: April 2007

Dengue virus envelope protein (E) contains two N-linked glycosylation sites, at Asn-67 and Asn-153. The glycosylation site at position 153 is conserved in most flaviviruses, while the site at position 67 is thought to be unique for dengue viruses. N-linked oligosaccharide side chains on flavivirus E proteins have been associated with viral morphogenesis, infectivity, and tropism. Here, we examined the relevance of each N-linked glycan on dengue virus E protein by removing each site in the context of infectious viral particles. Dengue viruses lacking Asn-67 were able to infect mammalian cells and translate and replicate the viral genome, but production of new infectious particles was abolished. In addition, dengue viruses lacking Asn-153 in the E showed reduced infectivity. In contrast, ablation of one or both glycosylation sites yielded viruses that replicate and propagate in mosquito cells. Furthermore, we found a differential requirement of N-linked glycans for E secretion in mammalian and mosquito cells. While secretion of E lacking Asn-67 was efficient in mosquito cells, secretion of the same protein expressed in mammalian cells was dramatically impaired. Finally, we found that viruses lacking the carbohydrate at position 67 showed reduced infection of immature dendritic cells, suggesting interaction between this glycan and the lectin DC-SIGN. Overall, our data defined different roles for the two glycans present at the E protein during dengue virus infection, highlighting the involvement of distinct host functions from mammalian and mosquito cells during dengue virus propagation.
Inefficient Transmission of H5N1 Influenza Viruses in a Ferret Contact Model
Authors: Yen Hui-Ling , Lipatov Aleksandr S. , Ilyushina Natalia A. , Govorkova Elena A. , Franks John , Yilmaz Neziha , Douglas Alan , Hay Alan , Krauss Scott , Rehg Jerold E. , Hoffmann Erich , Webster Robert G.
Published: April 2007

The abilities to infect and transmit efficiently among humans are essential for a novel influenza A virus to cause a pandemic. To evaluate the pandemic potential of widely disseminated H5N1 influenza viruses, a ferret contact model using experimental groups comprised of one inoculated ferret and two contact ferrets was used to study the transmissibility of four human H5N1 viruses isolated from 2003 to 2006. The effects of viral pathogenicity and receptor binding specificity (affinity to synthetic sialosaccharides with α2,3 or α2,6 linkages) on transmissibility were assessed. A/Vietnam/1203/04 and A/Vietnam/JP36-2/05 viruses, which possess “avian-like” α2,3-linked sialic acid (SA) receptor specificity, caused neurological symptoms and death in ferrets inoculated with 10
3
50% tissue culture infectious doses. A/Hong Kong/213/03 and A/Turkey/65-596/06 viruses, which show binding affinity for “human-like” α2,6-linked SA receptors in addition to their affinity for α2,3-linked SA receptors, caused mild clinical symptoms and were not lethal to the ferrets. No transmission of A/Vietnam/1203/04 or A/Turkey/65-596/06 virus was detected. One contact ferret developed neutralizing antibodies to A/Hong Kong/213/03 but did not exhibit any clinical signs or detectable virus shedding. In two groups, one of two naïve contact ferrets had detectable virus after 6 to 8 days when housed together with the A/Vietnam/JP36-2/05 virus-inoculated ferrets. Infected contact ferrets showed severe clinical signs, although little or no virus was detected in nasal washes. This limited virus shedding explained the absence of secondary transmission from the infected contact ferret to the other naïve ferret that were housed together. Our results suggest that despite their receptor binding affinity, circulating H5N1 viruses retain molecular determinants that restrict their spread among mammalian species.
Dominance of a Nonpathogenic Glycoprotein Gene over a Pathogenic Glycoprotein Gene in Rabies Virus
Authors: Faber Milosz , Faber Marie-Luise , Li Jianwei , Preuss Mirjam A. R. , Schnell Matthias J. , Dietzschold Bernhard
Published: April 2007

The nonpathogenic phenotype of the live rabies virus (RV) vaccine SPBNGAN is determined by an Arg→Glu exchange at position 333 in the glycoprotein, designated GAN. We recently showed that after several passages of SPBNGAN in mice, an Asn→Lys mutation arose at position 194 of GAN, resulting in GAK, which was associated with a reversion to the pathogenic phenotype. Because an RV vaccine candidate containing two GAN genes (SPBNGAN-GAN) exhibits increased immunogenicity in vivo compared to the single-GAN construct, we tested whether the presence of two GAN genes might also enhance the probability of reversion to pathogenicity. Comparison of SPBNGAN-GAN with RVs constructed to contain either both GAN and GAK genes (SPBNGAN-GAK and SPBNGAK-GAN) or two GAK genes (SPBNGAK-GAK) showed that while SPBNGAK-GAK was pathogenic, SPBNGAN-GAN and SPBNGAN-GAK were completely nonpathogenic and SPBNGAK-GAN showed strongly reduced pathogenicity. Analysis of genomic RV RNA in mouse brain tissue revealed significantly lower virus loads in SPBNGAN-GAK- and SPBNGAK-GAN-infected brains than those detected in SPBNGAK-GAK-infected brains, indicating the dominance of the nonpathogenic phenotype determined by GAN over the GAK-associated pathogenic phenotype. Virus production and viral RNA synthesis were markedly higher in SPBNGAN-, SPBNGAK-GAN-, and SPBNGAN-GAK-infected neuroblastoma cells than in the SPBNGAK- and SPBNGAK-GAK-infected counterparts, suggesting control of GAN dominance at the level of viral RNA synthesis. These data point to the lower risk of reversion to pathogenicity of a recombinant RV carrying two identical GAN genes compared to that of an RV carrying only a single GAN gene.
Bystander Attenuation of Neuronal and Astrocyte Intercellular Communication by Murine Cytomegalovirus Infection of Glia
Authors: Ho Winson S. C. , van den Pol Anthony N.
Published: April 2007

Astrocytes are the first cells infected by murine cytomegalovirus (MCMV) in primary cultures of brain. These cells play key roles in intercellular signaling and neuronal development, and they modulate synaptic activity within the nervous system. Using ratiometric fura-2 digital calcium imaging of >8,000 neurons and glia, we found that MCMV-infected astrocytes showed an increase in intracellular basal calcium levels and an enhanced response to neuroactive substances, including glutamate and ATP, and to high potassium levels. Cultured neurons with no sign of MCMV infection showed attenuated synaptic signaling after infection of the underlying astrocyte substrate, and intercellular communication between astrocytes with no sign of infection was reduced by the presence of infected glia. These bystander effects would tend to cause further deterioration of cellular communication in the brain in addition to the problems caused by the loss of directly infected cells.
Multiple Restrictions of Human Immunodeficiency Virus Type 1 in Feline Cells
Authors: Münk Carsten , Zielonka Jörg , Constabel Hannelore , Kloke Björn-Philipp , Rengstl Benjamin , Battenberg Marion , Bonci Francesca , Pistello Mauro , Löchelt Martin , Cichutek Klaus
Published: April 2007

The productive replication of human immunodeficiency virus type 1 (HIV-1) occurs exclusively in defined cells of human or chimpanzee origin, explaining why heterologous animal models for HIV replication, pathogenesis, vaccination, and therapy are not available. This lack of an animal model for HIV-1 studies prompted us to examine the susceptibility of feline cells in order to evaluate the cat (Felis catus) as an animal model for studying HIV-1. Here, we report that feline cell lines harbor multiple restrictions with respect to HIV-1 replication. The feline CD4 receptor does not permit virus infection. Feline T-cell lines MYA-1 and FeT-1C showed postentry restrictions resulting in low HIV-1 luciferase reporter activity and low expression of viral Gag-Pol proteins when pseudotyped vectors were used. Feline fibroblastic CrFK and KE-R cells, expressing human CD4 and CCR5, were very permissive for viral entry and HIV-long terminal repeat-driven expression but failed to support spreading infection. KE-R cells displayed a profound block with respect to release of HIV-1 particles. In contrast, CrFK cells allowed very efficient particle production; however, the CrFK cell-derived HIV-1 particles had low specific infectivity. We subsequently identified feline apolipoprotein B-editing catalytic polypeptide 3 (feAPOBEC3) proteins as active inhibitors of HIV-1 particle infectivity. CrFK cells express at least three different APOBEC3s: APOBEC3C, APOBEC3H, and APOBEC3CH. While the feAPOBEC3C did not significantly inhibit HIV-1, the feAPOBEC3H and feAPOBEC3CH induced G to A hypermutations of the viral cDNA and reduced the infectivity ∼10- to ∼40-fold.
POINTWISE CONSTRUCTION OF LIPSCHITZ AGGREGATION OPERATORS WITH SPECIFIC PROPERTIES
Authors: BELIAKOV GLEB , CALVO TOMASA , LAZARO JESUS
Published: April 2007

This paper describes an approach to pointwise construction of general aggregation operators, based on monotone Lipschitz approximation. The aggregation operators are constructed from a set of desired values at certain points, or from empirically collected data. It establishes tight upper and lower bounds on Lipschitz aggregation operators with a number of different properties, as well as the optimal aggregation operator, consistent with the given values. We consider conjunctive, disjunctive and idempotent n-ary aggregation operators; p-stable aggregation operators; various choices of the neutral element and annihilator; diagonal, opposite diagonal and marginal sections; bipolar and double aggregation operators. In all cases we provide either explicit formulas or deterministic numerical procedures to determine the bounds. The findings of this paper are useful for construction of aggregation operators with specified properties, especially using interpolation schemata.
Carbonic anhydrase XIV in skeletal muscle: subcellular localization and function from wild-type and knockout mice
Authors: Wetzel Petra , Scheibe Renate J. , Hellmann Bernd , Hallerdei Janine , Shah Gul N. , Waheed Abdul , Gros Gerolf , Sly William S.
Published: April 2007

The expression of carbonic anhydrase (CA) XIV was investigated in mouse skeletal muscles. Sarcoplasmic reticulum (SR) and sarcolemmal (SL) membrane fractions were isolated from wild-type (WT) and CA XIV knockout (KO) mice. The CA XIV protein of 54 kDa was present in SR and SL membrane fractions as shown by Western blot analysis. CA activity measurements of WT and KO membrane fractions showed that CA XIV accounts for ∼50% and 66% of the total CA activities determined in the SR and SL fractions, respectively. This indicates the presence of at least one other membrane-associated CA isoform in these membranes, e.g., CA IV, CA IX, or CA XII. Muscle fibers of the extensor digitorum longus (EDL) muscle were immunostained with anti-CA XIV/FITC and anti-sarco(endo)plasmic reticulum Ca2+-ATPase 1/TRITC, with anti-CA XIV/FITC and anti-ryanodine receptor/TRITC, or with anti-CA XIV/FITC and anti-monocarboxylate transporter-4/TRITC. CA XIV was expressed in the plasma membrane and in the longitudinal SR but not in the terminal SR. Isometric contraction measurements of single twitches and tetani and a fatigue protocol applied to fiber bundles of the fast-twitch EDL and of the slow-twitch soleus muscle from WT and KO mice showed that the lack of SR membrane-associated CA XIV did not affect maximum force, rise and relaxation times, and fatigue behavior. Thus, it is concluded that a reduction of the total SR CA activity by ∼50% in CA XIV KO mice does not lead to an impairment of SR function.
MicroRNA-206 is overexpressed in the diaphragm but not the hindlimb muscle of mdx mouse
Authors: McCarthy John J. , Esser Karyn A. , Andrade Francisco H.
Published: April 2007

MicroRNAs are highly conserved, noncoding RNAs involved in posttranscriptional gene silencing. MicroRNAs have been shown to be involved in a range of biological processes, including myogenesis and muscle regeneration. The objective of this study was to test the hypothesis that microRNA expression is altered in dystrophic muscle, with the greatest change occurring, of the muscles examined, in the diaphragm. The expression of the muscle-enriched microRNAs was determined in the soleus, plantaris, and diaphragm muscles of control and dystrophin-deficient ( mdx) mice by semiquantitative PCR. In the soleus and plantaris, expression of the mature microRNA 133a (miR-133a) and miR-206, respectively, was decreased by ∼25%, whereas in the diaphragm, miR-206 expression increased by 4.5-fold relative to control. The increased expression of miR-206 in the mdx diaphragm was paralleled by a 4.4-fold increase in primary miRNA-206 (pri-miRNA-206) transcript level. Expression of Myod1 was elevated 2.7-fold only in the mdx diaphragm, consistent with an earlier finding demonstrating Myod1 can activate pri-miRNA-206 transcription. Transcript levels of Drosha and Dicer, major components of microRNA biogenesis pathway, were unchanged in mdx muscle, suggesting the pathway is not altered under dystrophic conditions. Previous in vitro analysis found miR-206 was capable of repressing utrophin expression; however, under dystrophic conditions, both utrophin transcript and protein levels were significantly increased by 69% and 3.9-fold, respectively, a finding inconsistent with microRNA regulation. These results are the first to report alterations in expression of muscle-enriched microRNAs in skeletal muscle of the mdx mouse, suggesting microRNAs may have a role in the pathophysiology of muscular dystrophy.
Insulin increases the expression of contractile phenotypic markers in airway smooth muscle
Authors: Schaafsma Dedmer , McNeill Karol D. , Stelmack Gerald L. , Gosens Reinoud , Baarsma Hoeke A. , Dekkers Bart G. J. , Frohwerk Erin , Penninks Jelte-Maarten , Sharma Pawan , Ens Karen M. , Nelemans S. Adriaan , Zaagsma Johan , Halayko Andrew J. , Meurs Herman
Published: April 2007

We have previously demonstrated that long-term exposure of bovine tracheal smooth muscle (BTSM) strips to insulin induces a functional hypercontractile phenotype. To elucidate molecular mechanisms by which insulin might induce maturation of contractile phenotype airway smooth muscle (ASM) cells, we investigated effects of insulin stimulation in serum-free primary BTSM cell cultures on protein accumulation of specific contractile phenotypic markers and on the abundance and stability of mRNA encoding these markers. In addition, we used microscopy to assess insulin effects on ASM cell morphology, phenotype, and induction of phosphatidylinositol (PI) 3-kinase signaling. It was demonstrated that protein and mRNA levels of smooth muscle-specific contractile phenotypic markers, including sm-myosin, are significantly increased after stimulation of cultured BTSM cells with insulin (1 μM) for 8 days compared with cells treated with serum-free media, whereas mRNA stability was unaffected. In addition, insulin treatment promoted the formation of large, elongate ASM cells, characterized by dramatic accumulation of contractile phenotype marker proteins and phosphorylated p70S6K (downstream target of PI 3-kinase associated with ASM maturation). Insulin effects on protein accumulation and cell morphology were abrogated by combined pretreatment with the Rho kinase inhibitor Y-27632 (1 μM) or the PI 3-kinase inhibitor LY-294002 (10 μM), indicating that insulin increases the expression of contractile phenotypic markers in BTSM in a Rho kinase- and PI 3-kinase-dependent fashion. In conclusion, insulin increases transcription and protein expression of contractile phenotypic markers in ASM. This could have important implications for the use of recently approved aerosolized insulin formulations in diabetes mellitus.
Ferritin: a novel mechanism for delivery of iron to the brain and other organs
Authors: Fisher J. , Devraj K. , Ingram J. , Slagle-Webb B. , Madhankumar A. B. , Liu X. , Klinger M. , Simpson I. A. , Connor J. R.
Published: April 2007

Traditionally, transferrin has been considered the primary mechanism for cellular iron delivery, despite suggestive evidence for additional iron delivery mechanisms. In this study we examined ferritin, considered an iron storage protein, as a possible delivery protein. Ferritin consists of H- and L-subunits, and we demonstrated iron uptake by ferritin into multiple organs and that the uptake of iron is greater when the iron is delivered via H-ferritin compared with L-ferritin. The delivery of iron via H-ferritin but not L-ferritin was significantly decreased in mice with compromised iron storage compared with control, indicating that a feedback mechanism exists for H-ferritin iron delivery. To further evaluate the mechanism of ferritin iron delivery into the brain, we used a cell culture model of the blood-brain barrier to demonstrate that ferritin is transported across endothelial cells. There are receptors that prefer H-ferritin on the endothelial cells in culture and on rat brain microvasculature. These studies identify H-ferritin as an iron transport protein and suggest the presence of an H-ferritin receptor for mediating iron delivery. The relative amount of iron that could be delivered via H-ferritin could make this protein a predominant player in cellular iron delivery.
Wnt5a secretion stimulated by the extracellular calcium-sensing receptor inhibits defective Wnt signaling in colon cancer cells
Authors: MacLeod R. John , Hayes Madeline , Pacheco Ivan
Published: April 2007

To understand the role of the colonic extracellular calcium-sensing receptor (CaSR) in calcium chemoprotection against colon cancer, we activated the CaSR with 5 mM Ca2+ on HT-29 cells, an adenocarcinoma cell line. High Ca2+ stimulated the upregulation (as assessed by RT-PCR) and the secretion of Wnt5a (assessed by Western blot), a noncanonical Wnt family member. Inhibiting CaSR activity with a short interfering RNA (siRNA) duplex against the CaSR reduced CaSR protein and prevented the secretion of Wnt5a. Dominant negative CaSR (R185Q) or siRNA blocked the high Ca2+-mediated inhibition of the β-catenin reporter TOPflash. The CaSR/Wnt5a inhibition of β-catenin reporter was prevented by dominant negative ubiquitin ligase seven in absentia homolog 2 (Siah2). In low-calcium medium, overexpressing Wnt5a increased Siah2 amplicons and protein. Inducing the expression of full-length adenomatous polyposis coli (APC) prevented CaSRmediated increases of Siah2 and Wnt5a. Overexpressing the receptor tyrosine kinase-like orphan receptor 2 (Ror2) increased Wnt5a and CaSR-mediated inhibition of TOPflash. Conditioned medium from Wnt5a-transfected cells added to HT-29 cells in low-Ca2+ medium inhibited the β-catenin reporter. This inhibition was blocked dose responsively by Frizzled-8/Fc chimeric antibody. Overexpression of Ror2 in HT-29 cells in low-Ca2+ medium increased the inhibition of β-catenin reporter caused by recombinant Wnt5a protein compared with addition of Wnt5a protein alone. Our findings demonstrate that APC status plays a key role as a determinant of Wnt5a secretion and suggest that CaSR-mediated secretion of Wnt5a will inhibit defective Wnt signaling in APC-truncated cells in an autocrine manner.
S100A1: a novel inotropic regulator of cardiac performance. Transition from molecular physiology to pathophysiological relevance
Authors: Most Patrick , Remppis Andrew , Pleger Sven T. , Katus Hugo A. , Koch Walter J.
Published: April 2007

Here we review the considerable body of evidence that has accumulated to support the notion of S100A1, a cardiac-specific Ca2+-sensor protein of the EF-hand type, as a physiological regulator of excitation-contraction coupling and inotropic reserve mechanisms in the mammalian heart. In particular, molecular mechanisms will be discussed conveying the Ca2+-dependent inotropic actions of S100A1 protein in cardiomyocytes occurring independently of β-adrenergic signaling. Moreover, we will shed light on the molecular structure-function relationship of S100A1 with its cardiac target proteins at the sarcoplasmic reticulum, the sarcomere, and the mitochondria. Furthermore, pathophysiological consequences of disturbed S100A1 protein expression on altered Ca2+handling and intertwined systems in failing myocardium will be highlighted. Subsequently, therapeutic options by means of genetic manipulation of cardiac S100A1 expression will be discussed, aiming to complete our current understanding of the role of S100A1 in diseased myocardium.
Role of huddling on the energetic of growth in a newborn altricial mammal
Authors: Gilbert Caroline , Blanc Stéphane , Giroud Sylvain , Trabalon Marie , Maho Yvon Le , Perret Martine , Ancel André
Published: April 2007

Huddling is considered as a social strategy to reduce thermal stress and promote growth in newborn altricial mammals. So far, the role of huddling on the allocation of saved energy has not been quantified nor have the related impacts on body temperature rhythms. To determine the energy partitioning of rabbit pups either raised alone or in groups of eight, four, or two individuals, when thermoregulatory inefficient (TI) and efficient (TE), we first investigated their total energy expenditure and body composition. We then monitored body temperature and activity rhythms to test whether huddling may impact these rhythms, centered on the suckling event. Pups in a group of eight utilized 40% less energy for thermogenesis when TI than did pups alone and 32% less energy when TE. Pups in groups of eight and four had significantly lower thermoregulatory costs in the TI period, whereas pups in groups of two, four, and eight had lower costs during the TE period. Huddling pups could therefore channel the energy saved into processes of growth and accrued more fat mass (on average 4.5 ± 1.4 g) than isolated pups, which lost 0.7 g of fat. Pups in groups of four and eight had a body temperature significantly higher by 0.8°C than pups in groups of two and one when TI, whereas no more differences were noted when the TE period was reached. Moreover, pups alone showed an endogenous circadian body temperature rhythm that differed when compared with that of huddling pups, with no rise before suckling. Thus huddling enables pups to invest the saved energy into growth and to regulate their body temperature to be more competitive during nursing, particularly at the early time when they are TI.
Skeletal muscle nNOSμ protein content is increased by exercise training in humans
Authors: McConell Glenn K. , Bradley Scott J. , Stephens Terry J. , Canny Benedict J. , Kingwell Bronwyn A. , Lee-Young Robert S.
Published: April 2007

The major isoform of nitric oxide synthase (NOS) in skeletal muscle is the splice variant of neuronal NOS, termed nNOSμ. Exercise training increases nNOSμ protein levels in rat skeletal muscle, but data in humans are conflicting. We performed two studies to determine 1) whether resting nNOSμ protein expression is greater in skeletal muscle of 10 endurance-trained athletes compared with 11 sedentary individuals ( study 1) and 2) whether intense short-term (10 days) exercise training increases resting nNOSμ protein (within whole muscle and also within types I, IIa, and IIx fibers) in eight sedentary individuals ( study 2). In study 1, nNOSμ protein was ∼60% higher ( P < 0.05) in endurance-trained athletes compared with the sedentary participants. In study 2, nNOSμ protein expression was similar in types I, IIa, and IIx fibers before training. Ten days of intense exercise training significantly ( P < 0.05) increased nNOSμ protein levels in types I, IIa, and IIx fibers, a finding that was validated by using whole muscle samples. Endothelial NOS and inducible NOS protein were barely detectable in the skeletal muscle samples. In conclusion, nNOSμ protein expression is greater in endurance-trained individuals when compared with sedentary individuals. Ten days of intense exercise is also sufficient to increase nNOSμ expression in untrained individuals, due to uniform increases of nNOSμ within types I, IIa, and IIx fibers.
Identification and localization of BK-β subunits in the distal nephron of the mouse kidney
Authors: Grimm P. Richard , Foutz Ruth M. , Brenner Robert , Sansom Steven C.
Published: April 2007

Large-conductance, Ca2+-activated K+channels (BK), comprised of pore-forming α- and accessory β-subunits, secrete K+in the distal nephron under high-flow and high-K+diet conditions. BK channels are detected by electrophysiology in many nephron segments; however, the accessory β-subunit associated with these channels has not been determined. We performed RT-PCR, Western blotting, and immunohistochemical staining to determine whether BK-β1 is localized to the connecting tubule's principal-like cells (CNT) or intercalated cells (ICs), and whether BK-β2-4 are present in other distal nephron segments. RT-PCR and Western blots revealed that the mouse kidney expresses BK-β1, BK-β2, and BK-β4. Available antibodies in conjunction with BK-β1−/−and BK-β4−/−mice allowed the specific localization of BK-β1 and BK-β4 in distal nephron segments. Immunohistochemical staining showed that BK-β1 is localized in the CNT but not ICs of the connecting tubule. The localization of BK-β4 was discerned using an anti-BK-β4 antibody on wild-type tissue and anti-GFP on GFP-replaced BK-β4 mouse (BK-β4−/−) tissue. Both antibodies (anti-BK-β4 and anti-GFP) localized BK-β4 to the thick ascending limb (TAL), distal convoluted tubule (DCT), and ICs of the distal nephron. It is concluded that BK-β1 is narrowly confined to the apical membrane of CNTs in the mouse, whereas BK-β4 is expressed in the TAL, DCT, and ICs.
Oxidative stress reduces renal dopamine D1 receptor-Gq/11α G protein-phospholipase C signaling involving G protein-coupled receptor kinase 2
Authors: Banday Anees Ahmad , Lokhandwala Mustafa F.
Published: April 2007

The dopamine D1 receptors (D1R), expressed in renal proximal tubules, participate in the regulation of sodium transport. A defect in the coupling of the D1R to its G protein/effector complex in renal tubules has been reported in various conditions associated with oxidative stress. Because G protein-coupled receptor kinases (GRKs) are known to play an important role in D1R desensitization, we tested the hypothesis that increased oxidative stress in obese Zucker rats may cause GRK2 upregulation and, subsequently, D1R dysfunction. Lean and obese rats were given normal diet or diet supplemented with antioxidant lipoic acid for 2 wk. Compared with lean rats, obese rats exhibited oxidative stress, D1R were uncoupled from Gq/11α at basal level, and SKF-38393 failed to elicit D1R-G protein coupling, stimulate phospholipase C (PLC), and inhibit Na-K-ATPase activity. These animals showed increased basal protein kinase C (PKC) activity and membranous translocation of GRK2 and increased GKR2-Gq/11α interaction and D1R serine phosphorylation. Enzymatic dephosphorylation of D1R restored SKF-38393-induced adenylyl cyclase stimulation but not PLC activation. Treatment of obese rats with lipoic acid restored D1R-G protein coupling and SKF-38393-induced PLC stimulation and Na-K-ATPase inhibition. Lipoic acid treatment also normalized PKC activity, GRK2 sequestration, and GKR2-Gq/11α interaction. In conclusion, these data show that oxidative stress increases PKC activity causing GRK2 membranous translocation. GRK2 interacts with Gq/11α and acts, at least in part, as a regulator of G protein signaling leading to the D1R-Gq/11α uncoupling, causing inability of SKF-38393 to stimulate PLC and inhibit Na/K-ATPase. Lipoic acid, while reducing oxidative stress, normalized PKC activity and restored D1R-Gq/11α-PLC signaling and the ability of SKF-38393 to inhibit Na-K-ATPase activity.
Chronic intermittent hypoxia modulates eosinophil- and neutrophil-platelet aggregation and inflammatory cytokine secretion caused by strenuous exercise in men
Authors: Wang Jong-Shyan , Lin Hung-Yu , Cheng Mei-Ling , Wong May-Kuen
Published: April 2007

Although acclimatization to intermittent hypoxia (IH) improves exercise performance by increasing oxygen delivery and utilization, the effects of chronic IH on platelet-leukocyte interaction and inflammation-related cytokine secretion caused by strenuous exercise remain unclear. This investigation elucidates how two intensities of IH influence eosinophil- and neutrophil-platelet aggregation (EPA and NPA) as well as pro- and anti-inflammatory cytokines mediated by strenuous exercise. Twenty healthy sedentary men were randomly divided into severe (SIH) and moderate (MIH) IH groups; groups were exposed to 12% O2 (SIH) and 15% O2 (MIH) for 1 h/day, respectively, for 5 days/wk for 8 wk in a normobaric hypoxia chamber. Before IH intervention, 1) exercise up to maximal oxygen consumption promoted shear stress-, LPS-, and N-formyl-methionyl-leucyl-phenylalanine-induced EPA, increased IL-1β and malondialdehyde levels, and decreased total antioxidant levels in plasma and 2) exposure to 12% O2, but not to 15% O2 for 1 h, enhanced LPS-induced EPA and reduced plasma total antioxidant levels. After IH for 8 wk, hypoxia- and exercise-promoted EPA, IL-1β, or malondialdehyde levels were suppressed in both MIH and SIH groups, and plasma IL-6 and IL-10 levels in the SIH group were increased. However, the NPA induced by the shear force and chemical agonists was not changed under the two IH regimens. Therefore, both MIH and SIH regimens ameliorate eosinophil- and platelet-related thrombosis, proinflammatory IL-1β secretion, and lipid peroxidation enhanced by strenuous exercise. Furthermore, SIH simultaneously increases circulatory anti-inflammatory IL-6 and IL-10 concentrations. These findings can help to develop effective IH regimens that improve aerobic fitness and minimize risk of thromboinflammation.
Thermic effect of food and β-adrenergic thermogenic responsiveness in habitually exercising and sedentary healthy adult humans
Authors: Stob Nicole R. , Bell Christopher , van Baak Marleen A. , Seals Douglas R.
Published: April 2007

The thermic effect of food (TEF) is an important physiological determinant of total daily energy expenditure (EE) and energy balance. TEF is believed to be mediated in part by sympathetic nervous system activation and consequent β-adrenergic receptor (β-AR) stimulation of metabolism. TEF is greater in habitually exercising than in sedentary adults, despite similar postprandial sympathetic nervous system activation. We determined whether augmented TEF in habitually exercising adults is associated with enhanced peripheral thermogenic responsiveness to β-AR stimulation. In separate experiments in 22 sedentary and 29 habitually exercising adults, we measured the increase in EE (indirect calorimetry, ventilated hood) during β-AR stimulation (intravenous isoproterenol: 6, 12, and 24 ng·kg fat-free mass−1·min−1) and EE before and after a liquid meal (40% of resting EE; 53% carbohydrate, 32% fat, 15% protein). The increase in EE during incremental isoproterenol administration was greater ( P = 0.01) in habitual exercisers (0.34 ± 0.03, 0.54 ± 0.04, 0.81 ± 0.05 kJ/min; means ± SE) than in sedentary adults (0.26 ± 0.03, 0.40 ± 0.03, 0.64 ± 0.04 kJ/min). The area under the TEF response curve was also greater ( P = 0.04) in habitual exercisers (160 ± 9 kJ) than in sedentary adults (130 ± 11 kJ) and was positively related to β-AR thermogenic responsiveness ( r = 0.32, P = 0.02). We conclude that TEF is related to β-AR thermogenic responsiveness and that the greater TEF in habitual exercisers is attributable in part to their augmented β-AR thermogenic responsiveness. Our results also suggest that peripheral thermogenic responsiveness to β-AR stimulation is a physiological determinant of TEF and hence energy balance in healthy adult humans.
Rapid and Precise Control of Sniffing During Olfactory Discrimination in Rats
Authors: Kepecs Adam , Uchida Naoshige , Mainen Zachary F.
Published: April 2007

Olfactory perception relies on an active sampling process, sniffing, to rapidly deliver odorants from the environment to the olfactory receptors. The respiration cycle strongly patterns the flow of information into the olfactory systems, but the behavioral significance of particular sniffing patterns is not well understood. Here, we monitored the frequency and timing of nasal respiration in rats performing an odor-mixture–discrimination task that allowed us to test subjects near psychophysical limits and to quantify the precise timing of their behavior. We found that respiration frequencies varied widely from 2 to 12 Hz, but odor discrimination was dependent on 6- to 9-Hz sniffing: rats almost always entered and maintained this frequency band during odor sampling and their accuracy on difficult discrimination dropped when they did not. Moreover, the switch from baseline respiration to sniffing occurred not in response to odor delivery but in anticipation of odor sampling and was executed rapidly, almost always within a single cycle. Interestingly, rats also switched from respiration to rapid sniffing in anticipation of reward delivery, but in a distinct frequency band, 9–12 Hz. These results demonstrate the speed and precision of control over respiration and its significance for olfactory behavioral performance.
Postural Responses Evoked by Platform Pertubations Are Dominated by Continuous Feedback
Authors: van der Kooij Herman , de Vlugt Erwin
Published: April 2007

Is human balance control dominated by time invariant continuous feedback mechanisms or do noncontinuous mechanisms play a significant role like intermittent control? The goal of this paper is to quantify how much of the postural responses evoked by pseudorandom external periodic perturbations can be explained by continuous time invariant feedback control. Nine healthy subjects participated in this study. Center of mass and ankle torque responses were elicited by periodic platform perturbations in forward-backward directions containing energy in the 0.06- to 4.5-Hz frequency band. Subjects had their eyes open (EO) or eyes closed (EC). Responses were decomposed into a periodic component and a remnant (stochastic) component using spectral analysis. It is concluded that periodic responses can explain most of the evoked responses, although the remnant power spectral densities (PSDs) were significant especially for slow responses (<0.2 Hz) and largest for EC. The found remnant PSD did depend on the sensory condition but not on the platform perturbation amplitude. The ratio of the body sway and ankle torque remnant PSD reflects the body dynamics. Both findings are consistent with the idea that estimation of body orientation is part of a continuous feedback loop and that (stochastic) estimation errors increase when one source of sensory information is removed. The findings are not consistent with the idea that discrete or discontinuous intermittent feedback mechanisms significantly shape postural responses.
Role of the Cerebellum in Externally Paced Rhythmic Finger Movements
Authors: Del Olmo Miguel Fernandez , Cheeran Binith , Koch Giacomo , Rothwell John C.
Published: April 2007

Several studies have suggested that the cerebellum has an important role in timing of subsecond intervals. Previous studies using transcranial magnetic stimulation (TMS) to test this hypothesis directly have produced inconsistent results. Here we used 1-Hz repetitive TMS (rTMS) for 10 min over the right or left cerebellar hemisphere to interfere transiently with cerebellar processing to assess its effect on the performance of a finger-tapping task. Subjects tapped with their right index finger for 1 min (synchronization phase) with an auditory or visual cue at 0.5, 1, or 2 Hz; they continued for a further 1 min at the same rate with no cues (continuation phase). The blocks of trials were performed in a random order. rTMS of the cerebellum ipsilateral to the movement increased the variability of the intertap interval but only for movements at 2 Hz that were made while subjects were synchronizing with an auditory cue. There was no effect on the continuation phase of the task when the cues were no longer present or on synchronization with a visual cue. Similar results were seen after stimulation over the contralateral dorsal premotor cortex but not after rTMS over supplementary motor area. There was no effect after rTMS over the ipsilateral right cervical nerve roots or over the ipsilateral primary motor cortex. The results support the hypothesis of neural network for event-related timing in the subsecond range that involves a cerebellar-premotor network.
Eigenvalue problems for a quasilinear elliptic equation on ℝN
Authors: Poulou Marilena N. , Stavrakakis Nikolaos M.
Published: April 2007

We prove the existence of a simple, isolated, positive principal eigenvalue for the quasilinear elliptic equation −Δpu = λg(x)|u|p−2u, x ∈ ℝN, lim|x|→+∞u(x) = 0, where Δpu = div(|∇u|p−2∇u) is the p‐Laplacian operator and the weight function g(x), being bounded, changes sign and is negative and away from zero at infinity.
More on reverse triangle inequality in inner product spaces
Authors: Ansari A. H. , Moslehian M. S.
Published: April 2007

Refining some results of Dragomir, several new reverses of the generalized triangle inequality in inner product spaces are given. Among several results, we establish some reverses for the Schwarz inequality. In particular, it is proved that if a is a unit vector in a real or complex inner product space (H; 〈..〉), r, s > 0, p ∈ (0, s], D = {x ∈ H, ‖rx − sa‖ ≤ p}, x1, x2 ∈ D − {0}, and , then .
Transitional vortices in wide‐gap spherical annulus flow
Authors: Ifidon E. O.
Published: April 2007

We develop a semianalytic formulation suitable for solving the Navier‐Stokes equations governing the induced steady, axially symmetric motion of an incompressible viscous fluid confined in a wide gap between two differentially rotating concentric spheres. The method is valid for arbitrarily high Reynolds number and aids in the presentation of multiple steady‐state flow patterns and their bifurcations. In the case of a rotating inner sphere and a stationary outer sphere, linear stability analysis is conducted to determine whether or not the computed solutions are stable. It is found that the solution transforms smoothly into an unstable solution beginning with asymmetric vortex pairs identified near the point of a symmetry‐breaking bifurcation which occurs at Reynolds number 589. This solution transforms smoothly into an unstable asymmetric vortex solution as the Reynolds number increases. Flow modes whose branches have not been previously reported are found using this method. The origin of the flow modes obtained are discussed using bifurcation theory.
Weakly tight functions and their decomposition
Authors: Khare Mona , Singh Bhawna
Published: April 2007

The present paper deals with the study of a weakly tight function and its relation to tight functions. We obtain a Jordan‐decomposition‐type theorem for a locally bounded weakly tight real‐valued function defined on a sublattice of IX, followed by the notion of a total variation.
On the Lebedev transformation in Hardy′s spaces
Authors: Yakubovich Semyon B.
Published: April 2007

We establish the inverse Lebedev expansion with respect to
parameters and arguments of the modified Bessel functions for an
arbitrary function from Hardy′s space H2,A, A > 0. This gives another version of the Fourier‐integral‐type theorem for
the Lebedev transform. The result is generalized for a weighted
Hardy space , 0 < A < 1, of analytic functions f(z), z = Rez + iτ, in the strip |Rez| ≤ A. Boundedness and inversion properties
of the Lebedev transformation from this space into the space
L2(ℝ+; x−1dx) are considered. When Rez = 0, we derive the familiar Plancherel theorem for the
Kontorovich‐Lebedev transform.
On starlikeness and close‐to‐convexity of certain analyticfunctions
Authors: Kwon Oh Sang , Cho Nak Eun
Published: April 2007

Our purpose is to derive some sufficient conditions for
starlikeness and close‐to‐convexity of order α of certain analytic functions in the open unit disk.
Marcinkiewicz integrals along subvarieties on product domains
Authors: Al-Salman Ahmad
Published: April 2007

We study the Lp mapping properties of a class of Marcinkiewicz integral operators on product domains with rough kernels supported by subvarieties.
Properties of some ∗‐dense‐in‐itself subsets
Authors: Devi V. Renuka , Sivaraj D. , Chelvam T. Tamizh
Published: April 2007

ℐ‐open sets were introduced and studied by Janković and Hamlett (1990) to generalize the well‐known Banach category theorem. Quasi‐ℐ‐openness was introduced and studied by Abd El‐Monsef et al. (2000). These are ∗‐dense‐in‐itself sets of the ideal spaces. In this note, properties of these sets are further investigated and characterizations of these sets are given. Also, their relation with ℐ‐dense sets and ℐ‐locally closed sets is discussed. Characterizations of completely codense ideals are given in terms of semi‐preopen sets.
Combination of anti‐optimization and fuzzy‐set‐based analysis for structural optimization under uncertainty
Authors: Fang J. , Smith S. M. , Elishakoff I.
Published: April 2007

An approach to the optimum design of structures, in which uncertainties with a fuzzy nature in the magnitude of the loads are considered, is proposed in this study. The optimization process under fuzzy loads is transformed into a fuzzy optimization problem based on the notion of
Werners′ maximizing set by defining membership functions of the objective function and constraints. In this paper, Werner′s maximizing set is defined using the results obtained by first conducting an optimization through anti‐optimization modeling of the uncertain loads. An example of a ten‐bar truss is used to illustrate the present optimization process. The results are compared with those yielded by other optimization methods.
Another point of view on proportional navigation
Authors: Duflos E. , Penel P. , Vanbeeghe P. , Borne P.
Published: April 2007

Proportional navigation is one of the most popular and one of the most used of the guidance laws. But the way it is studied is always the same: the acceleration needed to reach a known
target is derived or analyzed. This way of studying guidance laws is called “the direct problem” by the authors. On the contrary, the problem considered here is to find, from the knowledge of a part of the trajectory of a maneuvering object, the target of this object. The authors call this way of studying guidance laws “the inverse problem”.