bluuebunny/crossref_metadata_2025 huggingface dataset:
Plasma Asymmetric Dimethylarginine, Symmetric Dimethylarginine,l‐Arginine, and Nitrite/Nitrate Concentrations in Cats with Chronic Kidney Disease and Hypertension
Authors: Jepson R.E. , Syme H.M. , Vallance C. , Elliott J.
Published: December 2008

Background:Chronic kidney disease (CKD) and hypertension have been associated with decreased bioavailability of nitric oxide (NO) and endothelial dysfunction. Increased concentrations of the endothelial nitric oxide synthase (eNOS) inhibitor asymmetric dimethylarginine (ADMA) are implicated.

Hypothesis:Plasma ADMA concentration is increased in cats with CKD and systemic hypertension corresponding to a decrease in total plasma nitrate/nitrite (NOx) availability. Decrease in systolic blood pressure (SBP) and proteinuria during treatment of hypertension with amlodipine besylate may be associated with increased NOxavailability.

Animals:Sixty‐nine client‐owned normotensive and hypertensive cats with variable azotemia.

Methods:Plasma ADMA, symmetric dimethylarginine (SDMA), andl‐arginine were measured simultaneously by hydrophilic‐interaction liquid chromatography‐electrospray tandem mass spectrometry in cats from 6 groups: normotensive nonazotemic (n = 10), normotensive mildly azotemic (n = 10), hypertensive mildly azotemic with hypertensive retinopathy (n = 20), hypertensive mildly azotemic without hypertensive retinopathy (n = 10), normotensive moderately azotemic cats (n = 10), and hypertensive nonazotemic cats (n = 9). Plasma NOxconcentrations were measured.

Results:A moderate correlation between plasma creatinine and ADMA (n = 69,r= .608,P< .001), SDMA (n = 69,r= .741,P< .001), and NOxconcentrations (n = 69,r= .589,P< .001) was observed. There was no association among plasma ADMA, SDMA, and NOxconcentrations and SBP.

Conclusions and Clinical Importance:Plasma ADMA and SDMA concentrations are increased in cats with CKD and correlate with plasma creatinine concentration. This may imply the presence of endothelial dysfunction in cats with CKD. Plasma ADMA concentrations were not associated with systemic hypertension. Treatment of systemic hypertension with amlodipine besylate did not affect plasma ADMA or NOxconcentrations.
Risk of Hemolytic Anemia with Intravenous Administration of Famotidine to Hospitalized Cats
Authors: De Brito Galvao J.F. , Trepanier L.A.
Published: December 2008

Background: Famotidine administered IV has been associated anecdotally with hemolysis in cats, and some veterinarians recommend using injectable famotidine only by the subcutaneous (SC) route for cats. However, the actual risk of such a reaction is not known.

Hypothesis: We hypothesized that famotidine, when given IV slowly, would not be associated with a clinically significant drop in packed cell volume (PCV) in hospitalized cats.

Animals: One hundred and forty‐two hospitalized cats.

Methods: A retrospective medical record review was performed for hospitalized cats prescribed famotidine IV (n = 56), famotidine SC (n = 48), or no famotidine (n = 38) at a veterinary medical teaching hospital over the period from January 2004 through December 2006.

Results: Baseline signalment, observation times, and famotidine dosage (in treated cats) were similar among groups. Median baseline PCVs were significantly lower in the IV (31.5%) and SC (32.0%) groups compared with the control group (35.0%; P= .04). The median percent drop in PCV (3–4%), however, was no different in cats that received famotidine by either route compared with the control group (P= .90), and no cats in either famotidine group were observed to have any clinical signs of hemolysis.

Conclusions and Clinical Importance: We conclude from this retrospective study that famotidine IV was given to 56 hospitalized cats without evidence of hemolysis, and that the IV route appeared safe when famotidine was administered over 5 minutes. We could not document a safety advantage of SC versus IV administration in this group of cats.
Risk Factors for Owner‐Reported Occurrence of Equine Protozoal Myeloencephalitis in the US Equine Population
Authors: Morley P.S. , Traub‐Dargatz J.L. , Benedict K.M. , Saville W.J.A. , Voelker L.D. , Wagner B.A.
Published: December 2008

Background:Equine protozoal myeloencephalitis (EPM) is a serious and often fatal neurologic disease of horses, but few studies have investigated risk factors.

Objectives:To evaluate operation‐ and individual‐level factors associated with likelihood of the occurrence of EPM.

Animals:Data were collected as part of a study of the US equine industry from 1,178 operations representing 83.9% of horses and 51.6% of operations with ≥3 horses in 28 states.

Methods:Probability‐based sampling was used to enroll representative operations in a cross‐sectional study. Interviews were conducted to collect information regarding health and management of horses. A nested case‐control study was used to investigate risk factors among individual horses. Interview data were combined with climate data, human population density, and opossum regional ecology categories. Data were analyzed using logistic regression to identify risk factors for the occurrence of EPM.

Results:Owners reported that 95% of EPM cases included in this study were diagnosed by veterinarians. Variables associated with EPM occurrence on premises included opossum regional ecology, reported exposure to small wildlife, climate, terrain, housing, choice of bedding material, method of storing feeds, equine stocking density, and primary use of horses. Among individual horses, age was most strongly associated with disease risk. Associations also were identified with sex, breed, primary use, and participation in competitions.

Conclusions and Clinical Importance:Because the risk of EPM occurrence on operations is closely tied to factors that impact exposure to opossums, their feces, and their environment, controlling these exposures may be important in preventing the occurrence of EPM.
Comparison of 3 Ultrasound Methods for Quantifying Left Ventricular Systolic Function: Correlation with Disease Severity and Prognostic Value in Dogs with Mitral Valve Disease
Authors: Serres F. , Chetboul V. , Tissier R. , Poujol L. , Gouni V. , Carlos Sampedrano C. , Pouchelon J.‐L.
Published: December 2008

Background: End‐systolic volume index (ESVI) is a marker of systolic function, which can be assessed by the geometric (GM, based on Teichholz formula) or 2 planimetric methods (PM, Simpson's derived and length area methods).

Hypothesis: Systolic dysfunction (SyD) may be observed in dogs with mitral valve disease (MVD) and is better assessed by PM than GM, which does not take into account the longitudinal left ventricular systolic shortening.

Animals: Six healthy dogs were used to determine the variability of the tested variables (Study 1). These variables were then prospectively assessed (Study 2) in 101 small breed dogs: 77 dogs with MVD and 24 healthy controls (CD).

Methods: ESVI was measured by GM and PM in awake dogs.

Results: All within‐ and between‐day coefficients of variation were <11% (Study 1). For Study 2, a nonlinear overestimation of ESVI was observed by GM compared with PM. PM‐derived ESVI was significantly increased in ISACHC class 3 dogs compared with ISACHC class 1 dogs and exerted a significant influence on cardiac events at 5 months in dogs with MVD from ISACHC classes 2 and 3 (P < .05).

Conclusions and Clinical Importance: ESVI can be calculated by GM and PM with good repeatability and reproducibility. However, GM overestimates ESVI in a nonlinear way. Therefore, PM‐derived ESVI should be preferred for the detection of SyD that is present at the late stages of the disease.
A Simplified Approach for Predicting the Intermittent Behavior of Gas-Liquid Mixtures in Pipes
Authors: Fossa M. , Marchitto A.
Published: December 2008

A new approach to the classical slug flow model is here proposed based on an original correlation for the minimum liquid level in the stratified regions of intermittent horizontal flows. This correlation is obtained by fitting experimental data obtained from a statistical analysis of void fraction signals from ring impedance probes. The new procedure improves the original model in terms of computing time reduction and algorithm simplification. In addition, it is demonstrated that the new closure relationship can be derived with more consistent experimental results, with respect to the slug length, which is employed in the original approach. The predictions of the main flow parameters are presented with reference to the classical and new approach, and all the results are critically compared with literature experimental data. It is demonstrated that the simplified procedure is able to predict the pressure drops and average void fraction values in good agreement with experimental measurements, while only the slug frequency and slug length predictions are affected by poor reliability.
Evaluation of Boronic Acid Disk Tests for Differentiating KPC-Possessing
Klebsiella pneumoniae
Isolates in the Clinical Laboratory
Authors: Tsakris Athanassios , Kristo Ioulia , Poulou Aggeliki , Themeli-Digalaki Katerina , Ikonomidis Alexandros , Petropoulou Dimitra , Pournaras Spyros , Sofianou Danai
Published: December 2008

The worldwide increase in the occurrence and dissemination of KPC β-lactamases among gram-negative pathogens makes critical the early detection of these enzymes. Boronic acid disk tests using different antibiotic substrates were evaluated for detection of KPC-possessing
Klebsiella pneumoniae
isolates. A total of 57 genotypically confirmed KPC-possessing
K. pneumoniae
isolates with varying carbapenem MICs were examined. To measure the specificity of the tests, 106 non-KPC-possessing isolates (89
K. pneumoniae
and 17
Escherichia coli
isolates) were randomly selected among those exhibiting reduced susceptibility to cefoxitin, expanded-spectrum cephalosporins, or carbapenems. As many as 56, 53, and 40 of the non-KPC-possessing isolates harbored extended-spectrum β-lactamases, metallo-β-lactamases, and plasmid-mediated AmpC β-lactamases, respectively. By use of CLSI methodology and disks containing imipenem, meropenem, or cefepime, either alone or in combination with 400 μg of boronic acid, all 57 KPC producers gave positive results (sensitivity, 100%) whereas all 106 non-KPC producers were negative (specificity, 100%). The meropenem duplicate disk with or without boronic acid demonstrated the largest differences in inhibition zone diameters between KPC producers and non-KPC producers. By use of disks containing ertapenem, all isolates were correctly differentiated except for five AmpC producers that gave false-positive results (sensitivity, 100%; specificity, 95.3%). These practical and simple boronic acid disk tests promise to be very helpful for the accurate differentiation of KPC-possessing
K. pneumoniae
isolates, even in regions where different broad-spectrum β-lactamases are widespread.
Comparison of Commercial and In-House Real-Time PCR Assays Used for Detection of
Mycoplasma pneumoniae
Authors: Dumke Roger , Jacobs Enno
Published: December 2008

We tested two commercial and three in-house PCR assays under standardized conditions to detect
Mycoplasma pneumoniae
. All five procedures were able to demonstrate
M. pneumoniae
DNA in a concentration comparable to 1 CFU/μl, but the mean crossing points resulted in differences in the concentration of the genome copies of a factor of 20.
Herpes Simplex Virus Type 1 Thymidine Kinase Sequence Fused to the
lacZ
Gene Increases Levels of β-Galactosidase Activity per Genome of High-Capacity but Not First-Generation Adenoviral Vectors In Vitro and In Vivo
Authors: Puntel M. , Barrett R. J. , Mondkar S. , Saxena V. , Kroeger K. M. , Muhammad A. K. M. , Liu C. , Bondale N. , Sciascia S. , Xiong W. , Shi Y. , Salem A. , Zadmehr A. , Huynh P. , Palmer D. , Ng P. , Castro M. G. , Lowenstein P. R.
Published: December 2008

Increased transgene expression per vector genome is an important goal in the optimization of viral vectors for gene therapy. Herein we demonstrate that herpes simplex virus type 1 (HSV1) thymidine kinase (TK) gene sequences (1,131 bp) fused to the 3′ end of
lacZ
increase transgene expression from high-capacity adenoviral vectors (HCAd), but not from first-generation (Ad) vectors. The woodchuck hepatitis virus posttranscriptional regulatory element (WPRE), in contrast, increased transgene expression levels from Ad but not HCAd vectors. The differential activity of the HSV1 TK gene and WPRE sequences was detected both in vitro and in vivo and suggests potentially different mechanisms of action or the interaction of these elements with vector genomic sequences.
Template Usage Is Responsible for the Preferential Acquisition of the K65R Reverse Transcriptase Mutation in Subtype C Variants of Human Immunodeficiency Virus Type 1
Authors: Coutsinos Dimitrios , Invernizzi Cédric F. , Xu Hongtao , Moisi Daniela , Oliveira Maureen , Brenner Bluma G. , Wainberg Mark A.
Published: December 2008

We propose that a nucleotide template-based mechanism facilitates the acquisition of the K65R mutation in subtype C human immunodeficiency virus type 1 (HIV-1). Different patterns of DNA synthesis were observed using DNA templates from viruses of subtype B or C origin. When subtype C reverse transcriptase (RT) was employed to synthesize DNA from subtype C DNA templates, preferential pausing was seen at the nucleotide position responsible for the AAG-to-AGG K65R mutation. This did not occur when the subtype B RT and template were used. Template factors can therefore increase the probability of K65R development in subtype C HIV-1.
Binding and Relocalization of Protein Kinase R by Murine Cytomegalovirus
Authors: Child Stephanie J. , Geballe Adam P.
Published: December 2008

Many viruses have evolved mechanisms to evade the repression of translation mediated by protein kinase R (PKR). In the case of murine cytomegalovirus (MCMV), the protein products of two essential genes, m142 and m143, bind to double-stranded RNA (dsRNA) and block phosphorylation of PKR and eukaryotic initiation factor 2α. A distinctive feature of MCMV is that two proteins are required to block PKR activation whereas other viral dsRNA-binding proteins that prevent PKR activation contain all the necessary functions in a single protein. In order to better understand the mechanism by which MCMV evades the PKR response, we investigated the associations of pm142 and pm143 with each other and with PKR. Both pm142 and pm143 interact with PKR in infected and transfected cells. However, the ∼200-kDa pm142-pm143 complex that forms in these cells does not contain substantial amounts of PKR, suggesting that the interactions between pm142-pm143 and PKR are unstable or transient. The stable, soluble pm142-pm143 complex appears to be a heterotetramer consisting of two molecules of pm142 associated with each other, and each one binds to and stabilizes a monomer of pm143. MCMV infection also causes relocalization of PKR into the nucleus and to an insoluble cytoplasmic compartment. These results suggest a model in which the pm142-pm143 multimer interacts with PKR and causes its sequestration in cellular compartments where it is unable to shut off translation and repress viral replication.
ISG15 Arg151 and the ISG15-Conjugating Enzyme UbE1L Are Important for Innate Immune Control of Sindbis Virus
Authors: Giannakopoulos Nadia V. , Arutyunova Elena , Lai Caroline , Lenschow Deborah J. , Haas Arthur L. , Virgin Herbert Whiting
Published: December 2008

Interferon (IFN)-stimulated gene 15 (ISG15) is a ubiquitin-like molecule that conjugates to target proteins via a C-terminal LRLRGG motif and has antiviral function in vivo. We used structural modeling to predict human ISG15 (hISG15) residues important for interacting with its E1 enzyme, UbE1L. Kinetic analysis revealed that mutation of arginine 153 to alanine (R153A) ablated hISG15-hUbE1L binding and transthiolation of UbcH8. Mutation of other predicted UbE1L-interacting residues had minimal effects on the transfer of ISG15 from UbE1L to UbcH8. The capacity of hISG15 R153A to form protein conjugates in 293T cells was markedly diminished. Mutation of the homologous residue in mouse ISG15 (mISG15), arginine 151, to alanine (R151A) also attenuated protein ISGylation following transfection into 293T cells. We assessed the role of ISG15-UbE1L interactions in control of virus infection by constructing double subgenomic Sindbis viruses that expressed the mISG15 R151A mutant. While expression of mISG15 protected alpha/beta-IFN-receptor-deficient (IFN-αβR−/−) mice from lethality following Sindbis virus infection, expression of mISG15 R151A conferred no survival benefit. The R151A mutation also attenuated ISG15's ability to decrease Sindbis virus replication in IFN-αβR−/−mice or prolong survival of ISG15−/−mice. The importance of UbE1L was confirmed by demonstrating that mice lacking this ISG15 E1 enzyme were highly susceptible to Sindbis virus infection. Together, these data support a role for protein conjugation in the antiviral effects of ISG15.
Leader-Induced Phosphorylation of Nucleoporins Correlates with Nuclear Trafficking Inhibition by Cardioviruses
Authors: Porter Frederick W. , Palmenberg Ann C.
Published: December 2008

Picornaviruses disrupt nucleocytoplasmic trafficking pathways during infection. Poliovirus and rhinovirus inhibit nuclear protein import/export through a series of 2A protease-dependent cleavages within nuclear pore proteins (nucleoporins [Nups]), including Nup62, Nup98, and Nup153. Cardioviruses lack the same protease and instead affect trafficking inhibition through an activity mapped to their leader (L) protein, a 67- to 76-amino acid (aa) polypeptide with no known enzymatic activity. We have shown that L from encephalomyocarditis virus (EMCV) binds and inhibits the activity of Ran-GTPase, a key regulator of nucleocytoplasmic transport. We now report that recombinant EMCV L triggers the unregulated efflux of protein cargo from preloaded HeLa cell nuclei in cell-free reactions dependent upon
Xenopus
egg cytosol or HeLa cell-derived cytosol. Recombinant L was the only viral protein necessary for this activity or for nuclear protein import inhibition. Mutational disruption of the L protein zinc finger domain (C
19
A) abrogated the inhibitory activity for both import and efflux in cell extracts, but mutations in the C-terminal acidic domain of L (aa 37 to 61) did not. Notably, HeLa cell nuclei treated with L, or those from EMCV-infected cells, showed reproducibly altered patterns of nucleoporin phosphorylation. Nup62, Nup153, and Nup214 each became hyperphosphorylated in an L-dependent manner. Staurosporine, a broad-spectrum kinase inhibitor, blocked this phosphorylation and rescued nuclear import/export activity from L-dependent inhibition. Therefore, cardioviruses target the same group of nucleoporins as enteroviruses, but the effector mechanism triggered by L (or L-Ran complexes) involves a unique cytosol-dependent phosphorylation cascade rather than proteolysis.
Replication of Equine Infectious Anemia Virus in Engineered Mouse NIH 3T3 Cells
Authors: Zhang Baoshan , Montelaro Ronald C.
Published: December 2008

We employed the equine lentivirus equine infectious anemia virus (EIAV) to investigate the cellular restrictions for lentivirus replication in murine NIH 3T3 cells. The results of these studies demonstrate that NIH 3T3 cells expressing the EIAV receptor ELR1 and equine cyclin T1 supported productive replication of EIAV and produced infectious virions at levels similar to those found in a reference permissive equine cell line. The studies presented here demonstrate, for the first time, differential levels of restriction for EIAV and human immunodeficiency virus type 1 (HIV-1) replication in murine cells and suggest that these differences can be exploited to reveal critical virus-cell interactions required for HIV-1 assembly and budding of lentivirus particles.
The Hepatitis C Virus NS4B Protein Can
trans
-Complement Viral RNA Replication and Modulates Production of Infectious Virus
Authors: Jones Daniel M. , Patel Arvind H. , Targett-Adams Paul , McLauchlan John
Published: December 2008

Studies of the hepatitis C virus (HCV) life cycle have been aided by development of in vitro systems that enable replication of viral RNA and production of infectious virus. However, the functions of the individual proteins, especially those engaged in RNA replication, remain poorly understood. It is considered that NS4B, one of the replicase components, creates sites for genome synthesis, which appear as punctate foci at the endoplasmic reticulum (ER) membrane. In this study, a panel of mutations in NS4B was generated to gain deeper insight into its functions. Our analysis identified five mutants that were incapable of supporting RNA replication, three of which had defects in production of foci at the ER membrane. These mutants also influenced posttranslational modification and intracellular mobility of another replicase protein, NS5A, suggesting that such characteristics are linked to focus formation by NS4B. From previous studies, NS4B could not be
trans
-complemented in replication assays. Using the mutants that blocked RNA synthesis, defective NS4B expressed from two mutants could be rescued in
trans
-complementation replication assays by wild-type protein produced by a functional HCV replicon. Moreover, active replication could be reconstituted by combining replicons that were defective in NS4B and NS5A. The ability to restore replication from inactive replicons has implications for our understanding of the mechanisms that direct viral RNA synthesis. Finally, one of the NS4B mutations increased the yield of infectious virus by five- to sixfold. Hence, NS4B not only functions in RNA replication but also contributes to the processes engaged in virus assembly and release.
Live Attenuated Influenza Viruses Containing NS1 Truncations as Vaccine Candidates against H5N1 Highly Pathogenic Avian Influenza
Authors: Steel John , Lowen Anice C. , Pena Lindomar , Angel Matthew , Solórzano Alicia , Albrecht Randy , Perez Daniel R. , García-Sastre Adolfo , Palese Peter
Published: December 2008

Due to the high mortality associated with recent, widely circulating strains of H5N1 influenza virus in poultry, the recurring introduction of H5N1 viruses from birds to humans, and the difficulties in H5N1 eradication by elimination of affected flocks, an effective vaccine against HPAI (highly pathogenic avian influenza) is highly desirable. Using reverse genetics, a set of experimental live attenuated vaccine strains based on recombinant H5N1 influenza virus A/Viet Nam/1203/04 was generated. Each virus was attenuated through expression of a hemagglutinin protein in which the polybasic cleavage site had been removed. Viruses were generated which possessed a full-length NS1 or a C-terminally truncated NS1 protein of 73, 99, or 126 amino acids. Viruses with each NS genotype were combined with a PB2 polymerase gene which carried either a lysine or a glutamic acid at position 627. We predicted that glutamic acid at position 627 of PB2 would attenuate the virus in mammalian hosts, thus increasing the safety of the vaccine. All recombinant viruses grew to high titers in 10-day-old embryonated chicken eggs but were attenuated in mammalian cell culture. Induction of high levels of beta interferon by all viruses possessing truncations in the NS1 protein was demonstrated by interferon bioassay. The viruses were each found to be highly attenuated in a mouse model. Vaccination with a single dose of any virus conferred complete protection from death upon challenge with a mouse lethal virus expressing H5N1 hemagglutinin and neuraminidase proteins. In a chicken model, vaccination with a single dose of a selected virus encoding the NS1 1-99 protein completely protected chickens from lethal challenge with homologous HPAI virus A/Viet Nam/1203/04 (H5N1) and provided a high level of protection from a heterologous virus, A/egret/Egypt/01/06 (H5N1). Thus, recombinant influenza A/Viet Nam/1203/04 viruses attenuated through the introduction of mutations in the hemagglutinin, NS1, and PB2 coding regions display characteristics desirable for live attenuated vaccines and hold potential as vaccine candidates in poultry as well as in mammalian hosts.
Herpes Simplex Virus Type 1 ICP27 Induces p38 Mitogen-Activated Protein Kinase Signaling and Apoptosis in HeLa Cells
Authors: Gillis Peter A. , Okagaki Laura H. , Rice Stephen A.
Published: December 2008

The herpes simplex virus type 1 (HSV-1) protein ICP27 has been implicated in a variety of functions important for viral replication including host shutoff, viral gene expression, activation of mitogen-activated protein kinases p38 and Jun N-terminal protein kinase (JNK), and apoptosis inhibition. In the present study we sought to examine the functions of ICP27 in the absence of viral infection by creating stable HeLa cell lines that inducibly express ICP27. Here, we characterize two such cell lines and show that ICP27 expression is associated with a cellular growth defect. The observed defect is caused at least in part by the induction of apoptosis as indicated by caspase-3 activation, annexin V staining, and characteristic changes in cellular morphology. In an effort to identify the function of ICP27 responsible for inducing apoptosis, we show that ICP27 expression is sufficient to activate p38 signaling to a level that is similar to that observed during wild-type HSV-1 infection. However, ICP27 expression alone is unable to lead to a strong activation of JNK signaling. Using chemical inhibitors, we show that the ICP27-mediated activation of p38 signaling is responsible for the observed induction of apoptosis in the induced cell lines. Our findings suggest that during viral infection, ICP27 activates p38 and JNK signaling pathways via two distinct mechanisms. ICP27 directly activates p38 signaling, leading to stimulation of the host cell apoptotic pathways. In contrast, robust activation of JNK signaling by ICP27 requires one or more delayed early or late viral gene products and may be associated with the inhibition of apoptosis.
Attenuation of Rabies Virus Replication and Virulence by Picornavirus Internal Ribosome Entry Site Elements
Authors: Marschalek Adriane , Finke Stefan , Schwemmle Martin , Mayer Daniel , Heimrich Bernd , Stitz Lothar , Conzelmann Karl-Klaus
Published: December 2008

Gene expression of nonsegmented negative-strand RNA viruses is regulated at the transcriptional level and relies on the canonical 5′-end-dependent translation of capped viral mRNAs. Here, we have used internal ribosome entry sites (IRES) from picornaviruses to control the expression level of the phosphoprotein P of the neurotropic rabies virus (RV;
Rhabdoviridae
), which is critically required for both viral replication and escape from the host interferon response. In a dual luciferase reporter RV, the IRES elements of poliovirus (PV) and human rhinovirus type 2 (HRV2) were active in a variety of cell lines from different host species. While a generally lower activity of the HRV2 IRES was apparent compared to the PV IRES, specific deficits of the HRV2 IRES in neuronal cell lines were not observed. Recombinant RVs expressing P exclusively from a bicistronic nucleoprotein (N)-IRES-P mRNA showed IRES-specific reduction of replication in cell culture and in neurons of organotypic brain slice cultures, an increased activation of the beta interferon (IFN-β) promoter, and increased sensitivity to IFN. Intracerebral infection revealed a complete loss of virulence of both PV- and HRV2 IRES-controlled RV for wild-type mice and for transgenic mice lacking a functional IFN-α receptor (IFNAR
−/−
). The virulence of HRV2 IRES-controlled RV was most severely attenuated and could be demonstrated only in newborn IFNAR
−/−
mice. Translational control of individual genes is a promising strategy to attenuate replication and virulence of live nonsegmented negative-strand RNA viruses and vectors and to study the function of IRES elements in detail.
Effect of Preexisting Immunity on Oncolytic Adenovirus Vector INGN 007 Antitumor Efficacy in Immunocompetent and Immunosuppressed Syrian Hamsters
Authors: Dhar Debanjan , Spencer Jacqueline F. , Toth Karoly , Wold William S. M.
Published: December 2008

Immune responses against adenovirus (Ad) vectors pose a possible concern for the outcome of treatment efficacy. To address the role of preexisting immunity in oncolytic Ad vector antitumor efficacy following intratumoral injection of vector as well as tumor-to-tissue spread of the vector, we employed the Syrian hamster model. These animals are immunocompetent, and their tumors and tissues are permissive for replication of Ad type 5 (Ad5). We used the adenovirus death protein-overexpressing Ad5-based vector INGN 007. Subcutaneous tumors were established in groups of hamsters that were or were not immunized with Ad5. Half of the hamsters in these groups were immunosuppressed with cyclophosphamide. For all groups, tumors injected with INGN 007 grew significantly more slowly than those injected with buffer. Under immunocompetent conditions, there was no significant effect of preexisting immunity on vector antitumor efficacy. Soon after the tumors in naïve animals were injected with vector, the hamsters developed neutralizing antibody (NAb) and the difference in NAb titers between the naïve and immunized groups diminished. Under immunosuppressed conditions, preexisting NAb did significantly reduce vector efficacy. Thus, NAb do reduce vector efficacy to some extent, but immunosuppression is required to observe the effect. Regarding vector toxicity, there was spillover of vector from the tumor to the liver and lungs in naïve immunocompetent hamsters, and this was nearly eliminated in the immunized hamsters. Thus, preexisting immunity to Ad5 does not affect INGN 007 antitumor efficacy following intratumoral injection, but immunity prevents vector spillover from the tumor to the liver and lungs.
Role of Heparan Sulfate in Attachment to and Infection of the Murine Female Genital Tract by Human Papillomavirus
Authors: Johnson Katherine M. , Kines Rhonda C. , Roberts Jeffrey N. , Lowy Douglas R. , Schiller John T. , Day Patricia M.
Published: December 2008

The host factors required for in vivo infection have not been investigated for any papillomavirus. Using a recently developed murine cervicovaginal challenge model, we evaluated the importance of heparan sulfate proteoglycans (HSPGs) in human papillomavirus (HPV) infection of the murine female genital tract. We examined HPV type 16 (HPV16) as well as HPV31 and HPV5, for which some evidence suggests that they may differ from HPV16 in their utilization of HSPGs as their primary attachment factor in vitro. Luciferase-expressing pseudovirus of all three types infected the mouse genital tract, although HPV5, which normally infects nongenital epidermis, was less efficient. Heparinase III treatment of the genital tract significantly inhibited infection of all three types by greater than 90% and clearly inhibited virion attachment to the basement membrane and cell surfaces, establishing that HSPGs are the primary attachment factors for these three viruses in vivo. However, the pseudoviruses differed in their responses to treatment with various forms of heparin, a soluble analog of heparan sulfate. HPV16 and HPV31 infections were effectively inhibited by a highly sulfated form of heparin, but HPV5 was not, although it bound the compound. In contrast, a N-desulfated and N-acylated variant preferentially inhibited HPV5. Inhibition of infection paralleled the relative ability of the variants to inhibit basement membrane and cell surface binding. We speculate that cutaneous HPVs, such as HPV5, and genital mucosal HPVs, such as HPV16 and -31, may have evolved to recognize different forms of HSPGs to enable them to preferentially infect keratinocytes at different anatomical sites.
Limited Effects of Fasting on Hepatitis B Virus (HBV) Biosynthesis in HBV Transgenic Mice
Authors: Li Lie , Oropeza Claudia E. , Kaestner Klaus H. , McLachlan Alan
Published: December 2008

Nuclear receptors have a unique role in governing hepatitis B virus (HBV) transcription and replication. Hepatocyte nuclear factor 4α (HNF4α) and retinoid X receptor α (RXRα) plus peroxisome proliferator-activated receptor α (PPARα) have been shown to support viral biosynthesis in nonhepatoma cells in the absence of additional liver-enriched transcription factors. However, the in vivo importance of these nuclear receptors in HBV biosynthesis has been investigated only to a limited extent. Fasting has been shown to activate gluconeogenesis, in part, by activating PPARγ coactivator 1 α, which in turn leads to activation of HNF4α- and RXRα/PPARα-mediated transcription. As HBV pregenomic RNA synthesis is primarily believed to be regulated by HNF4α under normal physiological conditions, it was of interest to determine the effect of fasting on the levels of HBV RNA and DNA synthesis. Fasting was shown to rather modestly increase the levels of viral proteins, transcripts, and replication intermediates in the HBV transgenic mouse model of chronic viral infection, suggesting that caloric restriction may modulate viremia to some extent during natural infection.
Injury and social determinants among in-school adolescents in six African countries
Authors: Peltzer K
Published: December 2008

Background:

There is a lack of data on injury and its social correlates among in-school adolescents in Africa.

Objectives:

To estimate the prevalence of injury among adolescents in six African countries, and to examine the consistency of associations cross-nationally between sociodemographics, social risk factors, and the occurrence of adolescent injury in Africa.

Design:

Cross-sectional national data from the Global School-based Health Survey (GSHS) conducted in six African countries between 2003 and 2004.

Setting:

Surveys administered in classrooms.

Subjects:

The sample included 20 765 students aged 13–15 years from six African countries (Kenya, Namibia, Swaziland, Uganda, Zambia, Zimbabwe) chosen by a two-stage cluster sample design to represent all students in grades 6, 7, 8, 9, and 10 in each country.

Results:

The mean percentage over all the countries of adolescents reporting one or more serious injuries within the past 12 months was 68.2%, ranging from 38.6% in Swaziland to 71.5% in Zambia. In multivariate regression analysis, risk behaviors were associated with annual injury prevalence, with the highest odds for loneliness, followed by hunger, truancy, depression, smoking, and drug use. The observed risk for all injuries, as well as injuries related to sports, motor vehicles, fighting, and burns, increased consistently with increasing number of risk behaviors.

Conclusions:

A high annual injury prevalence was found, and risk-taking played a role in the etiology of injury. There is a need to consider an integrated approach to injury etiology in planning injury prevention and safety promotion activities for schoolchildren, paying particular attention to lifestyle factors that have the potential to influence risk of injury.
What is lost when searching only one literature database for articles relevant to injury prevention and safety promotion?
Authors: Lawrence D W
Published: December 2008

Objective:

To assess what is lost if only one literature database is searched for articles relevant to injury prevention and safety promotion (IPSP) topics.

Method:

Serial textword (keyword, free-text) searches using multiple synonym terms for five key IPSP topics (bicycle-related brain injuries, ethanol-impaired driving, house fires, road rage, and suicidal behaviors among adolescents) were conducted in four of the bibliographic databases that are most used by IPSP professionals: EMBASE, MEDLINE, PsycINFO, and Web of Science. Through a systematic procedure, an inventory of articles on each topic in each database was conducted to identify the total unduplicated count of all articles on each topic, the number of articles unique to each database, and the articles available if only one database is searched.

Results:

No single database included all of the relevant articles on any topic, and the database with the broadest coverage differed by topic. A search of only one literature database will return 16.7–81.5% (median 43.4%) of the available articles on any of five key IPSP topics. Each database contributed unique articles to the total bibliography for each topic.

Conclusion:

A literature search performed in only one database will, on average, lead to a loss of more than half of the available literature on a topic.
Cell-permeable peptide-based disruption of endogenous PKA-AKAP complexes: a tool for studying the molecular roles of AKAP-mediated PKA subcellular anchoring
Authors: Faruque Omar M. , Le-Nguyen Dung , Lajoix Anne-Dominique , Vives Eric , Petit Pierre , Bataille Dominique , Hani El-Habib
Published: December 2008

Stimulation of numerous G protein-coupled receptors leads to the elevation of intracellular concentrations of cAMP, which subsequently activates the PKA pathway. Specificity of the PKA signaling module is determined by a sophisticated subcellular targeting network that directs the spatiotemporal activation of the kinase. This specific compartmentalization mechanism occurs through high-affinity interactions of PKA with A-kinase anchoring proteins (AKAPs), the role of which is to target the kinase to discrete subcellular microdomains. Recently, a peptide designated “AKAPis” has been proposed to competitively inhibit PKA-AKAP interactions in vitro. We therefore sought to characterize a cell-permeable construct of the AKAPis inhibitor and use it as a tool to characterize the impact of PKA compartmentalization by AKAPs. Using insulin-secreting pancreatic β-cells (INS-1 cells), we showed that TAT-AKAPis (at a micromolar range) dose dependently disrupted a significant fraction of endogenous PKA-AKAP interactions. Immunoflurescent analysis also indicated that TAT-AKAPis significantly affected PKA subcellular localization. Furthermore, TAT-AKAPis markedly attenuated glucagon-induced phosphorylations of p44/p42 MAPKs and cAMP response element binding protein, which are downstream effectors of PKA. In parallel, TAT-AKAPis dose dependently inhibited the glucagon-induced potentiation of insulin release. Therefore, AKAP-mediated subcellular compartmentalization of PKA represents a key mechanism for PKA-dependent phosphorylation events and potentiation of insulin secretion in intact pancreatic β-cells. More interestingly, our data highlight the effectiveness of the cell-permeable peptide-mediated approach to monitoring in cellulo PKA-AKAP interactions and delineating PKA-dependent phosphorylation events underlying specific cellular responses.
Interaction of monocarboxylate transporter 4 with β1-integrin and its role in cell migration
Authors: Gallagher Shannon M. , Castorino John J. , Philp Nancy J.
Published: December 2008

Monocarboxylate transporter (MCT) 4 is a heteromeric proton-coupled lactate transporter that is noncovalently linked to the extracellular matrix metalloproteinase inducer CD147 and is typically expressed in glycolytic tissues. There is increasing evidence to suggest that ion transporters are part of macromolecular complexes involved in regulating β1-integrin adhesion and cell movement. In the present study we examined whether MCTs play a role in cell migration through their interaction with β1-integrin. Using reciprocal coimmunoprecipitation assays, we found that β1-integrin selectively associated with MCT4 in ARPE-19 and MDCK cells, two epithelial cell lines that express both MCT1 and MCT4. In polarized monolayers of ARPE-19 cells, MCT4 and β1-integrin colocalized to the basolateral membrane, while both proteins were found in the leading edge lamellapodia of migrating cells. In scratch-wound assays, MCT4 knockdown slowed migration and increased focal adhesion size. In contrast, silencing MCT1 did not alter the rate of cell migration or focal adhesion size. Taken together, our findings suggest that the specific interaction of MCT4 with β1-integrin may regulate cell migration through modulation of focal adhesions.
Normotensive sodium loading in conscious dogs: regulation of renin secretion during β-receptor blockade
Authors: Bie Peter , Mølstrøm Simon , Wamberg Søren
Published: December 2008

Renin secretion is regulated in part by renal nerves operating through β1-receptors of the renal juxtaglomerular cells. Slow sodium loading may decrease plasma renin concentration (PRC) and cause natriuresis at constant mean arterial blood pressure (MAP) and glomerular filtration rate (GFR). We hypothesized that in this setting, renin secretion and renin-dependent sodium excretion are controlled by via the renal nerves and therefore are eliminated or reduced by blocking the action of norepinephrine on the juxtaglomerular cells with the β1-receptor antagonist metoprolol. This was tested in conscious dogs by infusion of NaCl (20 μmol·kg−1·min−1for 180 min, NaLoad) during regular or low-sodium diet (0.03 mmol·kg−1·day−1, LowNa) with and without metoprolol (2 mg/kg plus 0.9 mg·kg−1·h−1). Vasopressin V2receptors were blocked by Otsuka compound OPC31260 to facilitate clearance measurements. Body fluid volume was maintained by servocontrolled fluid infusion. Metoprolol per se did not affect MAP, heart rate, or sodium excretion significantly, but reduced PRC and ANG II by 30–40%, increased plasma atrial natriuretic peptide (ANP), and tripled potassium excretion. LowNa per se increased PRC (+53%), ANG II (+93%), and aldosterone (+660%), and shifted the vasopressin function curve to the left. NaLoad elevated plasma [Na+] by 4.5% and vasopressin by threefold, but MAP and plasma ANP remained unchanged. NaLoad decreased PRC by ∼30%, ANG II by ∼40%, and aldosterone by ∼60%, regardless of diet and metoprolol. The natriuretic response to NaLoad was augmented during metoprolol regardless of diet. In conclusion, PRC depended on dietary sodium and β1-adrenergic control as expected; however, the acute sodium-driven decrease in PRC at constant MAP and GFR was unaffected by β1-receptor blockade demonstrating that renin may be regulated without changes in MAP, GFR, or β1-mediated effects of norepinephrine. Low-sodium diet augments vasopressin secretion, whereas ANP secretion is reduced.
Normotensive sodium loading in normal man: regulation of renin secretion during β-receptor blockade
Authors: Mølstrøm Simon , Larsen Nils H. , Simonsen Jane A. , Washington Remon , Bie Peter
Published: December 2008

Saline administration may change renin-angiotensin-aldosterone system (RAAS) activity and sodium excretion at constant mean arterial pressure (MAP). We hypothesized that such responses are elicited mainly by renal sympathetic nerve activity by β1-receptors (β1-RSNA), and tested the hypothesis by studying RAAS and renal excretion during slow saline loading at constant plasma sodium concentration (Na+loading; 12 μmol Na+·kg−1·min−1for 4 h). Normal subjects were studied on low-sodium intake with and without β1-adrenergic blockade by metoprolol. Metoprolol per se reduced RAAS activity as expected. Na+loading decreased plasma renin concentration (PRC) by one-third, plasma ANG II by one-half, and plasma aldosterone by two-thirds (all P < 0.05); surprisingly, these changes were found without, as well as during, acute metoprolol administration. Concomitantly, sodium excretion increased indistinguishably with and without metoprolol (16 ± 2 to 71 ± 14 μmol/min; 13 ± 2 to 55 ± 13 μmol/min, respectively). Na+loading did not increase plasma atrial natriuretic peptide, glomerular filtration rate (GFR by51Cr-EDTA), MAP, or cardiac output (CO by impedance cardiography), but increased central venous pressure (CVP) by ∼2.0 mmHg ( P < 0.05). During Na+loading, sodium excretion increased with CVP at an average slope of 7 μmol·min−1·mmHg−1. Concomitantly, plasma vasopressin decreased by 30–40% ( P < 0.05). In conclusion, β1-adrenoceptor blockade affects neither the acute saline-mediated deactivation of RAAS nor the associated natriuretic response, and the RAAS response to modest saline loading seems independent of changes in MAP, CO, GFR, β1-mediated effects of norepinephrine, and ANP. Unexpectedly, the results do not allow assessment of the relative importance of RAAS-dependent and -independent regulation of renal sodium excretion. The results are compatible with the notion that at constant arterial pressure, a volume receptor elicited reduction in RSNA via receptors other than β1-adrenoceptors, decreases renal tubular sodium reabsorption proximal to the macula densa leading to increased NaCl concentration at the macula densa, and subsequent inhibition of renin secretion.
Dissociating Vision and Visual Attention in the Human Pulvinar
Authors: Smith A. T. , Cotton P. L. , Bruno A. , Moutsiana C.
Published: December 2008

The pulvinar region of the thalamus has repeatedly been linked with the control of attention. However, the functions of the pulvinar remain poorly characterized, both in human and in nonhuman primates. In a functional MRI study, we examined the relative contributions to activity in the human posterior pulvinar made by visual drive (the presence of an unattended visual stimulus) and attention (covert spatial attention to the stimulus). In an event-related design, large optic flow stimuli were presented to the left and/or right of a central fixation point. When unattended, the stimuli robustly activated two regions of the pulvinar, one medial and one dorsal with respect to the lateral geniculate. The activity in both regions shows a strong contralateral bias, suggesting retinotopic organization. Primate physiology suggests that the two regions could be two portions of the same double map of the visual field. In our paradigm, attending to the stimulus enhanced the response by about 20%. Thus attention is not necessary to activate the human pulvinar and the degree of attentional enhancement matches, but does not exceed, that seen in the cortical regions with which the posterior pulvinar connects.
Generalization of Gait Adaptation for Fall Prevention: From Moveable Platform to Slippery Floor
Authors: Bhatt T. , Pai Y. C.
Published: December 2008

A person's ability to transfer the acquired improvements in the control of center of mass (COM) state stability to slips induced in everyday conditions can have profound theoretical and practical implications for fall prevention. This study investigated the extent to which such generalization could take place. A training group ( n = 8) initially experienced 24 right-side slips in blocked-and-random order (from the 1st unannounced, novel slip, S-1 to the last, S-24) resulting from release of a low-friction moveable platform in walking. They then experienced a single unannounced slip while walking on an oil-lubricated vinyl floor surface (V-T). A control group ( n = 8) received only one unannounced slip on the same slippery floor (V-C). Results demonstrated that the incidence of balance loss and fall on V-T was comparable to that on S-24. In both trials, fall and balance-loss incidence was significantly reduced in comparison with that on S-1 or on V-C, resulting from significant improvements in the COM state stability. The observed generalization indicates that the control of COM stability can be optimally acquired to accommodate alterations in environmental constraints, and it may be broadly coded and easily modifiable within the CNS. Because of such mechanisms, it is possible that the locomotor-balance skills acquired with the aid of low-friction moveable platforms can translate into resisting falls encountered in daily living.