bluuebunny/crossref_metadata_2025 huggingface dataset:
Extended Multilocus Variable-Number Tandem-Repeat Analysis of Clostridium difficile Correlates Exactly with Ribotyping and Enables Identification of Hospital Transmission
Authors: Manzoor S. E. , Tanner H. E. , Marriott C. L. , Brazier J. S. , Hardy K. J. , Platt S. , Hawkey P. M.
Published: August 2011

PCR ribotyping is currently used in many countries for epidemiological investigation to track transmission and to identify emerging variants of
Clostridium difficile
. Although PCR ribotyping differentiates over 300 types, it is not always sufficiently discriminatory for epidemiological investigations particularly for common ribotypes, e.g., ribotypes 027, 106, and 017. Multilocus variable-number tandem-repeat analysis (MLVA) is a highly discriminatory molecular subtyping method that has been applied to a number of bacterial species for high-level subtyping. Two MLVA typing schemes for
C. difficile
have been previously published, each utilizing seven variable-number tandem-repeat (VNTR) loci on the genome with four loci common to both schemes. Although these schemes are good genotyping methods with the ability to discriminate between isolates, they do not identify the ribotype. We show here that increasing the number of VNTR loci to 15, creating the extended MLVA (eMLVA) scheme, we have successfully subtyped all clinically significant ribotypes while still clustering isolates in concordance with PCR ribotyping. The eMLVA scheme developed here provides insight into the genetic diversity of the
C. difficile
population at both global and cross-infection clusters in patient levels, with the possibility of replacing PCR ribotyping.
Analysis of Performance of a PCR-Based Assay To Detect DNA of Aspergillus fumigatus in Whole Blood and Serum: a Comparative Study with Clinical Samples
Authors: Bernal-Martínez Leticia , Gago Sara , Buitrago María J. , Gomez-Lopez Alicia , Rodríguez-Tudela Juan L. , Cuenca-Estrella Manuel
Published: August 2011

The performance of a real-time PCR-based assay was retrospectively analyzed (according to European Organization for Research and Treatment of Cancer/Mycosis Study Group criteria) in the samples of patients with invasive aspergillosis. A total of 711 serial samples (356 whole-blood and 355 serum samples) from 38 adult patients were analyzed. The
Aspergillus fumigatus
PCR assay results were positive for 89 of 356 (25%) whole-blood samples and 90 of 355 (25.35%) serum samples. Positive PCR results were seen in 29 of 31 (93.5%) patients for which serum was analyzed and in 31 of 33 (93.9%) cases with whole-blood specimens. Both blood and serum samples were available in 26 cases, and significant differences were not observed in this subgroup of cases. The average number of threshold cycles (

C
T

) for positive blood samples was 37.6, and the average

C
T

for serum was 37.4. The DNA concentration ranged between 2 and 50 fg per μl of sample, with average DNA concentrations of 10.2 and 11.7 fg in positive blood and serum samples, respectively (
P
> 0.01). The performance of this PCR-based quantitative assay was similar for both serum and blood samples. We recommend serum samples as the most convenient hematological sample to use for
Aspergillus
DNA quantification when serial determinations are done.
Performance of Xpert MTB/RIF RUO Assay and IS
6110
Real-Time PCR for Mycobacterium tuberculosis Detection in Clinical Samples
Authors: Miller Melissa B. , Popowitch Elena B. , Backlund Michael G. , Ager Edward P. C.
Published: August 2011

The Cepheid Xpert MTB/RIF research-use-only (RUO) assay and a laboratory-developed test (LDT) targeting IS
6110
were evaluated and compared to mycobacterial culture as the gold standard. The performance characteristics of both molecular assays were determined by using 112 specimens from 90 patients, including 89 pulmonary specimens and 23 extrapulmonary specimens. Of the specimens tested, 37 (33%) were culture positive for the
Mycobacterium tuberculosis
complex; 29 were pulmonary, and 8 were extrapulmonary. Of these culture-positive specimens, 83% of the pulmonary specimens and 50% of the extrapulmonary specimens were smear positive. There was complete concordance between the smear-positive culture-positive specimens, independent of the anatomical site (100% sensitivity). The sensitivity of the MTB/RIF RUO assay for smear-negative specimens was 60% for pulmonary and 75% for extrapulmonary specimens, while the IS
6110
LDT sensitivities were 40% and 0%, respectively. There was also complete concordance among the culture-negative specimens tested. Both assays showed 95% specificity, with four culture-negative specimens testing as positive. A review of patient records indicated that there was a high likelihood of the presence of
M. tuberculosis
complex DNA in the false-positive specimens. Biosafety analysis was performed and showed an acceptable reduction in organism viability using the processing methods described above. Both molecular assays are suitable for the detection of
M. tuberculosis
isolates in smear-positive pulmonary and extrapulmonary specimens, while the sensitivity of the detection of
M. tuberculosis
isolates in smear-negative specimens was variable.
Cross-Linking of Rotavirus Outer Capsid Protein VP7 by Antibodies or Disulfides Inhibits Viral Entry
Authors: Aoki Scott T. , Trask Shane D. , Coulson Barbara S. , Greenberg Harry B. , Dormitzer Philip R. , Harrison Stephen C.
Published: August 2011

Antibodies that neutralize rotavirus infection target outer coat proteins VP4 and VP7 and inhibit viral entry. The structure of a VP7-Fab complex (S. T. Aoki, et al., Science 324:1444-1447, 2009) led us to reclassify epitopes into two binding regions at inter- and intrasubunit boundaries of the calcium-dependent trimer. It further led us to show that antibodies binding at the intersubunit boundary inhibit uncoating of the virion outer layer. We have now tested representative antibodies for each of the defined structural epitope regions and find that antibodies recognizing epitopes in either binding region neutralize by cross-linking VP7 trimers. Antibodies that bind at the intersubunit junction neutralize as monovalent Fabs, while those that bind at the intrasubunit region require divalency. The VP7 structure has also allowed us to design a disulfide cross-linked VP7 mutant which recoats double-layered particles (DLPs) as efficiently as does wild-type VP7 but which yields particles defective in cell entry as determined both by lack of infectivity and by loss of α-sarcin toxicity in the presence of recoated particles. We conclude that dissociation of the VP7 trimer is an essential step in viral penetration into cells.
The Ectromelia Virus SPI-2 Protein Causes Lethal Mousepox by Preventing NK Cell Responses
Authors: Melo-Silva Carolina R. , Tscharke David C. , Lobigs Mario , Koskinen Aulikki , Wong Yik Chun , Buller R. Mark , Müllbacher Arno , Regner Matthias
Published: August 2011

Ectromelia virus (ECTV) is a natural pathogen of mice that causes mousepox, and many of its genes have been implicated in the modulation of host immune responses. Serine protease inhibitor 2 (SPI-2) is one of these putative ECTV host response modifier proteins. SPI-2 is conserved across orthopoxviruses, but results defining its mechanism of action andin vivofunction are lacking or contradictory. We studied the role of SPI-2 in mousepox by deleting theSPI-2gene or its serine protease inhibitor reactive site. We found that SPI-2 does not affect viral replication or cell-intrinsic apoptosis pathways, since mutant viruses replicatein vitroas efficiently as wild-type virus. However, in the absence of SPI-2 protein, ECTV is attenuated in mousepox-susceptible mice, resulting in lower viral loads in the liver, decreased spleen pathology, and substantially improved host survival. This attenuation correlates with more effective immune responses in the absence of SPI-2, including an earlier serum gamma interferon (IFN-γ) response, raised serum interleukin 18 (IL-18), increased numbers of granzyme B+CD8+T cells, and, most notably, increased numbers and activation of NK cells. Both virus attenuation and the improved immune responses associated with SPI-2 deletion from ECTV are lost when mice are depleted of NK cells. Consequently, SPI-2 renders mousepox lethal in susceptible strains by preventing protective NK cell defenses.
A Broadly Neutralizing Human Monoclonal Antibody That Recognizes a Conserved, Novel Epitope on the Globular Head of the Influenza H1N1 Virus Hemagglutinin
Authors: Krause Jens C. , Tsibane Tshidi , Tumpey Terrence M. , Huffman Chelsey J. , Basler Christopher F. , Crowe James E.
Published: August 2011

The conserved influenza virus hemagglutinin (HA) stem domain elicits cross-reactive antibodies, but epitopes in the globular head typically elicit strain-specific responses because of the hypervariability of this region. We isolated human monoclonal antibody 5J8, which neutralized a broad spectrum of 20th century H1N1 viruses and the 2009 pandemic H1N1 virus. Fine mapping of the interaction unexpectedly revealed a novel epitope between the receptor-binding pocket and the Ca
2
antigenic site on HA. This antibody exposes a new mechanism underlying broad immunity against H1N1 influenza viruses and identifies a conserved epitope that might be incorporated into engineered H1 virus vaccines.
Juxtaposition of Two Distant, Serine-Arginine-Rich Protein-Binding Elements Is Required for Optimal Polyadenylation in Rous Sarcoma Virus
Authors: Hudson Stephen W. , McNally Mark T.
Published: August 2011

The Rous sarcoma virus (RSV) polyadenylation site (PAS) is very poorly used
in vitro
due to suboptimal upstream and downstream elements, and yet ∼85% of viral transcripts are polyadenylated
in vivo
. The mechanisms that orchestrate polyadenylation at the weak PAS are not completely understood. It was previously shown that serine-arginine (SR)-rich proteins stimulate RSV PAS use
in vitro
and
in vivo
. It has been proposed that viral RNA polyadenylation is stimulated through a nonproductive splice complex that forms between a pseudo 5′ splice site (5′ss) within the negative regulator of splicing (NRS) and a downstream 3′ss, which repositions NRS-bound SR proteins closer to the viral PAS. This repositioning is thought to be important for long-distance poly(A) stimulation by the NRS. We report here that a 308-nucleotide deletion downstream of the
env
3′ss decreased polyadenylation efficiency, suggesting the presence of an additional element required for optimal RSV polyadenylation. Mapping studies localized the poly(A) stimulating element to a region coincident with the Env splicing enhancer, which binds SR proteins, and inactivation of the enhancer and SR protein binding decreased polyadenylation efficiency. The positive effect of the Env enhancer on polyadenylation could be uncoupled from its role in splicing. As with the NRS, the Env enhancer also stimulated use of the viral PAS
in vitro
. These results suggest that a critical threshold of SR proteins, achieved by juxtaposition of SR protein binding sites within the NRS and Env enhancer, is required for long-range polyadenylation stimulation.
Inhibition of Retromer Activity by Herpesvirus Saimiri Tip Leads to CD4 Downregulation and Efficient T Cell Transformation
Authors: Kingston Dior , Chang Heesoon , Ensser Armin , Lee Hye-Ra , Lee Jongsoo , Lee Sun-Hwa , Jung Jae Ung , Cho Nam-Hyuk
Published: August 2011

The mammalian retromer is an evolutionally conserved protein complex composed of a vacuolar protein sorting trimer (Vps 26/29/35) that participates in cargo recognition and a sorting nexin (SNX) dimer that binds to endosomal membranes. The retromer plays an important role in efficient retrograde transport for endosome-to-Golgi retrieval of the cation-independent mannose-6-phosphate receptor (CI-MPR), a receptor for lysosomal hydrolases, and other endosomal proteins. This ultimately contributes to the control of cell growth, cell adhesion, and cell migration. The herpesvirus saimiri (HVS) tyrosine kinase-interacting protein (Tip), required for the immortalization of primary T lymphocytes, targets cellular signaling molecules, including Lck tyrosine kinases and the p80 endosomal trafficking protein. Despite the pronounced effects of HVS Tip on T cell signal transduction, the details of its activity on T cell immortalization remain elusive. Here, we report that the amino-terminal conserved, glutamate-rich sequence of Tip specifically interacts with the retromer subunit Vps35 and that this interaction not only causes the redistribution of Vps35 from the early endosome to the lysosome but also drastically inhibits retromer activity, as measured by decreased levels of CI-MPR and lower activities of cellular lysosomal hydrolases. Physiologically, the inhibition of intracellular retromer activity by Tip is ultimately linked to the downregulation of CD4 surface expression and to the efficientin vitroimmortalization of primary human T cells to interleukin-2 (IL-2)-independent permanent growth. Therefore, HVS Tip uniquely targets the retromer complex to impair the intracellular trafficking functions of infected cells, ultimately contributing to efficient T cell transformation.
Reversion of PB2-627E to -627K during Replication of an H5N1 Clade 2.2 Virus in Mammalian Hosts Depends on the Origin of the Nucleoprotein
Authors: Bogs Jessica , Kalthoff Donata , Veits Jutta , Pavlova Sophia , Schwemmle Martin , Mänz Benjamin , Mettenleiter Thomas C. , Stech Jürgen
Published: August 2011

H5N1 highly pathogenic avian influenza viruses (HPAIV) of clade 2.2 spread from Southeast Asia to Europe. Intriguingly, in contrast to all common avian strains specifying glutamic acid at position 627 of the PB2 protein (PB2-627E), they carry a lysine at this position (PB2-627K), which is normally found only in human strains. To analyze the impact of this mutation on the host range of HPAIV H5N1, we altered PB2-627K to PB2-627E in the European isolate A/Swan/Germany/R65/2006 (R65). In contrast to the parental R65, multicycle growth and polymerase activity of the resulting mutant R65-PB2
K627E
were considerably impaired in mammalian but not in avian cells. Correspondingly, the 50% lethal dose (LD
50
) in mice was increased by three orders of magnitude, whereas virulence in chicken remained unchanged, resulting in 100% lethality, as was found for the parental R65. Strikingly, R65-PB2
K627E
reverted to PB2-627K after only one passage in mice but did not revert in chickens. To investigate whether additional R65 genes influence reversion, we passaged R65-PB2
K627E
reassortants containing genes from A/Hong Kong/156/97 (H5N1) (carrying PB2-627E), in avian and mammalian cells. Reversion to PB2-627K in mammalian cells required the presence of the R65 nucleoprotein (NP). This finding corresponds to results of others that during replication of avian strains in mammalian cells, PB2-627K restores an impaired PB2-NP association. Since this mutation is apparently not detrimental for virus prevalence in birds, it has not been eliminated. However, the prompt reversion to PB2-627K in MDCK cells and mice suggests that the clade 2.2 H5N1 HPAIV may have had a history of intermediate mammalian hosts.
Human Leukocyte Antigen Genotype and Risk of HIV Disease Progression before and after Initiation of Antiretroviral Therapy
Authors: Kuniholm Mark H. , Gao Xiaojiang , Xue Xiaonan , Kovacs Andrea , Anastos Kathryn , Marti Darlene , Greenblatt Ruth M. , Cohen Mardge H. , Minkoff Howard , Gange Stephen J. , Fazzari Melissa , Young Mary A. , Strickler Howard D. , Carrington Mary
Published: August 2011

While the human leukocyte antigen (HLA) genotype has been associated with the rate of HIV disease progression in untreated patients, little is known regarding these relationships in patients using highly active antiretroviral therapy (HAART). The limited data reported to date identified few HLA-HIV disease associations in patients using HAART and even occasional associations that were opposite of those found in untreated patients. We conducted high-resolution HLA class I and II genotyping in a random sample (n= 860) of HIV-seropositive women enrolled in a long-term cohort initiated in 1994. HLA-HIV disease associations before and after initiation of HAART were examined using multivariate analyses. In untreated HIV-seropositive patients, we observed many of the predicted associations, consistent with prior studies. For example, HLA-B*57 (β = −0.7; 95% confidence interval [CI] = −0.9 to −0.5;P= 5 × 10−11) and Bw4 (β = −0.2; 95% CI = −0.4 to −0.1;P= 0.009) were inversely associated with baseline HIV viral load, and B*57 was associated with a low risk of rapid CD4+decline (odds ratio [OR] = 0.2; 95% CI = 0.1 to 0.6;P= 0.002). Conversely, in treated patients, the odds of a virological response to HAART were lower for B*57:01 (OR = 0.2; 95% CI = 0.0 to 0.9;P= 0.03), and Bw4 (OR = 0.4; 95% CI = 0.1 to 1.0;P= 0.04) was associated with low odds of an immunological response. The associations of HLA genotype with HIV disease are different and sometimes even opposite in treated and untreated patients.
Phylogenetic Analysis of Murine Leukemia Virus Sequences from Longitudinally Sampled Chronic Fatigue Syndrome Patients Suggests PCR Contamination Rather than Viral Evolution
Authors: Katzourakis Aris , Hué Stéphane , Kellam Paul , Towers Greg J.
Published: August 2011

Xenotropic murine leukemia virus (MLV)-related virus (XMRV) has been amplified from human prostate cancer and chronic fatigue syndrome (CFS) patient samples. Other studies failed to replicate these findings and suggested PCR contamination with a prostate cancer cell line, 22Rv1, as a likely source. MLV-like sequences have also been detected in CFS patients in longitudinal samples 15 years apart. Here, we tested whether sequence data from these samples are consistent with viral evolution. Our phylogenetic analyses strongly reject a model of within-patient evolution and demonstrate that the sequences from the first and second time points represent distinct endogenous murine retroviruses, suggesting contamination.
The Role of the Blood-Brain Barrier during Venezuelan Equine Encephalitis Virus Infection
Authors: Schäfer Alexandra , Brooke Christopher B. , Whitmore Alan C. , Johnston Robert E.
Published: August 2011

Venezuelan equine encephalitis (VEE) virus is a mosquito-borne alphavirus associated with sporadic outbreaks in human and equid populations in the Western Hemisphere. After the bite of an infected mosquito, the virus initiates a biphasic disease: a peripheral phase with viral replication in lymphoid and myeloid tissues, followed by a neurotropic phase with infection of central nervous system (CNS) neurons, causing neuropathology and in some cases fatal encephalitis. The mechanisms allowing VEE virus to enter the CNS are currently poorly understood. Previous data have shown that the virus gains access to the CNS by infecting olfactory sensory neurons in the nasal mucosa of mice. However, at day 5 after inoculation, the infection of the brain is multifocal, indicating that virus particles are able to cross the blood-brain barrier (BBB). To better understand the role of the BBB during VEE virus infection, we used a well-characterized mouse model system. Using VEE virus replicon particles (VRP), we modeled the early events of neuroinvasion, showing that the replication of VRP in the nasal mucosa induced the opening of the BBB, allowing peripherally administered VRP to invade the brain. Peripheral VEE virus infection was characterized by a biphasic opening of the BBB. Further, inhibition of BBB opening resulted in a delayed viral neuroinvasion and pathogenesis. Overall, these results suggest that VEE virus initially enters the CNS through the olfactory pathways and initiates viral replication in the brain, which induces the opening of the BBB, allowing a second wave of invading virus from the periphery to enter the brain.
The Avian Influenza Virus NS1 ESEV PDZ Binding Motif Associates with Dlg1 and Scribble To Disrupt Cellular Tight Junctions
Authors: Golebiewski Lisa , Liu Hongbing , Javier Ronald T. , Rice Andrew P.
Published: August 2011

The influenza A virus NS1 protein contains a conserved 4-amino-acid-residue PDZ-ligand binding motif (PBM) at the carboxyl terminus that can function as a virulence determinant by targeting cellular PDZ proteins. The NS1 proteins from avian and human viral isolates have consensus PBM sequences ESEV and RSKV, respectively. Currently circulating highly pathogenic H5N1 viruses contain the ESEV PBM which specifically associates with the PDZ proteins Scribble, Dlg1, MAGI-1, MAGI-2, and MAGI-3. In this study, we found NS1 proteins from viral isolates that contain the PBM sequence RSKV, KSEV, or EPEV are unable to associate with these PDZ proteins. Other results showed that the ESEV PBM mediates an indirect association with PDZ protein, Lin7C, via an interaction with Dlg1. Infection with a virus that expresses a NS1 protein with the ESEV PBM results in colocalization of NS1, Scribble, and Dlg1 within perinuclear puncta and mislocalization of plasma membrane-associated Lin7C to the cytoplasm. Infection of polarized MDCK cells with the ESEV virus additionally results in functional disruption of the tight junction (TJ) as measured by altered localization of TJ markers ZO-1 and Occludin, decreased transepithelial electrical resistance, and increased fluorescein isothiocyanate (FITC)-inulin diffusion across the polarized cell monolayer. A similar effect on the TJ was observed in MDCK cells depleted for either Scribble or Dlg1 by small interfering RNA (siRNA). These findings indicate that ESEV PBM-mediated binding of NS1 to Scribble and Dlg1 functions to disrupt the cellular TJ and that this effect likely contributes to the severe disease associated with highly pathogenic H5N1 influenza A viruses.
Novel Reassortment of Eurasian Avian-Like and Pandemic/2009 Influenza Viruses in Swine: Infectious Potential for Humans
Authors: Zhu Huachen , Zhou Boping , Fan Xiaohui , Lam Tommy T. Y. , Wang Jia , Chen Antony , Chen Xinchun , Chen Honglin , Webster Robert G. , Webby Richard , Peiris Joseph S. M. , Smith David K. , Guan Yi
Published: August 2011

Pigs are considered to be intermediate hosts and “mixing vessels,” facilitating the genesis of pandemic influenza viruses, as demonstrated by the emergence of the 2009 H1N1 pandemic (pdm/09) virus. The prevalence and repeated introduction of the pdm/09 virus into pigs raises the possibility of generating novel swine influenza viruses with the potential to infect humans. To address this, an active influenza surveillance program was conducted with slaughtered pigs in abattoirs in southern China. Over 50% of the pigs tested were found to be seropositive for one or more H1 influenza viruses, most commonly pdm/09-like viruses. Out of 36 virus isolates detected, one group of novel reassortants had Eurasian avian-like swine H1N1 surface genes and pdm/09 internal genes. Animal experiments showed that this virus transmitted effectively from pig to pig and from pig to ferret, and it could also replicate in
ex vivo
human lung tissue. Immunization against the 2009 pandemic virus gave only partial protection to ferrets. The continuing prevalence of the pdm/09 virus in pigs could lead to the genesis of novel swine reassortant viruses with the potential to infect humans.
A Cluster of Basic Amino Acids in the Factor X Serine Protease Mediates Surface Attachment of Adenovirus/FX Complexes
Authors: Duffy Margaret R. , Bradshaw Angela C. , Parker Alan L. , McVey John H. , Baker Andrew H.
Published: August 2011

Hepatocyte transduction following intravenous administration of adenovirus 5 (Ad5) is mediated by interaction between coagulation factor X (FX) and the hexon. The FX serine protease (SP) domain tethers the Ad5/FX complex to hepatocytes through binding heparan sulfate proteoglycans (HSPGs). Here, we identify the critical HSPG-interacting residues of FX. We generated an FX mutant by modifying seven residues in the SP domain. Surface plasmon resonance demonstrated that mutations did not affect binding to Ad5. FX-mediated, HSPG-associated cell binding and transduction were abolished. A cluster of basic amino acids in the SP domain therefore mediates surface interaction of the Ad/FX complex.
Interaction of Reverse Transcriptase (RT) Mutations Conferring Resistance to Lamivudine and Etravirine: Effects on Fitness and RT Activity of Human Immunodeficiency Virus Type 1
Authors: Hu Zixin , Kuritzkes Daniel R.
Published: August 2011

Resistance to the nonnucleoside reverse transcriptase inhibitors etravirine and rilpivirine (RPV) is conferred by the E138K mutation in human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT). Clinical trials of RPV administered with lamivudine or emtricitabine showed the emergence of E138K together with M184I, which confers lamivudine and emtricitabine resistance in most patients with virologic failure. To understand why M184I was favored over M184V, we determined the drug susceptibility, infectivity, relative fitness, and reverse transcriptase activity of HIV-1 carrying E138K/M184I or E138K/M184V mutations. Whereas the replication capacity (RC) of the single mutants was reduced compared to that of the wild type (WT), the RC of the two double mutants was comparable to that of the WT in the absence of drug. The RC of the E138K/M184I mutant in the presence of etravirine was significantly greater than that of the E138K and E138K/M184V mutants; the RC of the double mutants was greater than that of the M184I or M184V mutant. Fitness profiles and growth competition experiments showed that the E138K/M184I mutant had a significant replicative advantage over the E138K/M184V mutant in the presence of etravirine and lamivudine. The virion-associated RT activity of the E138K, M184I, or M184V virus was significantly reduced compared to that of the WT, whereas the RT activity of the E138K/M184I virus was significantly greater than that of the WT or E138K/M184V virus. These results suggest that the E138K and M184I/V mutations are mutually compensatory and may explain the frequent occurrence of E138K/M184I after the virologic failure of rilpivirine-, lamivudine-, and emtricitabine-containing regimens.
The ability of a behaviour-specific patient questionnaire to identify poorly performing doctors
Authors: Fossli Jensen Bård , Dahl Fredrik A , Safran Dana Gelb , Garratt Andrew M , Krupat Edward , Finset Arnstein , Gulbrandsen Pål
Published: August 2011

Background

Doctors' ability to communicate with patients varies. Patient questionnaires are often used to assess doctors' communication skills.

Objective

To investigate whether the Four Habits Patient Questionnaire (4HPQ) can be used to assess the different skill levels of doctors.

Design

A cross-sectional study of 497 hospital encounters with 71 doctors. Encounters were videotaped and patients completed three post-visit questionnaires.

Setting

A 500-bed general teaching hospital in Norway.

Main outcome

The proportion of video-observed between-doctor variance that could be predicted by 4HPQ.

Results

There were strong correlations between all patient-reported outcomes (range 0.71–0.80 at the doctor level, p<0.01). 4HPQ correlated significantly with video-observed behaviour at the doctor level (Pearson's r=0.42, p<0.01) and the encounter level (Pearson's r=0.27, p<0.01). The proportion of between-doctor variance not detectable by 4HPQ was 88%. The reason for this discordance was large within-doctor between-encounter variance observed in the videos, and small between-patient variance in patient reports. The maximum positive predictive value for the identification of poorly performing doctors (92%) was achieved with a cut-off score for 4HPQ of 82% (ie, patient assessments were concordant with expert observers for these doctors).

Conclusion

Using a patient-reported questionnaire of doctors' communication skills, favourable assessments of doctors by patients were mostly discordant with the views of expert observers. Only very poor performance identified by patients was in agreement with the views of expert observers. The results suggest that patient reports alone may not be sufficient to identify all doctors whose communication skills need improvement training.
Feasibility study to assess the use of the Cincinnati stroke scale by emergency medical dispatchers: a pilot study: Figure 1
Authors: Govindarajan Prasanthi , Desouza Natalie T , Pierog Jessica , Ghilarducci David , Johnston S Claiborne
Published: August 2011

The emergency medical dispatcher (EMD) receiving a call via 911 is the first point of contact within the acute care system and plays an important role in early stroke recognition. Published studies show that the diagnostic accuracy of stroke of EMD needs to be improved. Therefore, the National Association of Emergency Medical Dispatchers implemented a stroke diagnostic tool modelled after the Cincinnati stroke scale across 3000 cities worldwide. This is the first time a diagnostic tool that requires callers to test physical findings and report those back to the EMD has been implemented. However, the ability of EMD and 911 callers to use this in real time has not been reported. The goal of this pilot study was to determine the feasibility of an EMD applying the Cincinnati stroke scale tool during a 911 call, and to report the time required to administer the tool.
Cationic ruthenium(III) maltolato–imidazole complexes — Synthesis, characterization, and antiproliferatory activity*Adapted from the Ph.D. thesis of D.C. Kennedy (see the References section).
Authors: Kennedy David C. , Patrick Brian O. , James Brian R.
Published: August 2011

The cationic RuIII complexes, trans-[Ru(ma)2(L)2]CF3SO3, where Hma = maltol = 3-hydroxy-2-methyl-4-pyrone; L = imidazole (Im) (complex 2), 1(N)-methylimidazole (N-MeIm) (3), 2-methylimidazole (2-MeIm) (4), and 4-methylimidazole (4-MeIm) (5), were synthesized via the known L = EtOH (complex 1a), and characterized by elemental analysis, 1H NMR and IR spectroscopies, mass spectrometry, cyclic voltammetry, and (for 3 and 4) by X-ray crystallography. The trans-[Ru(ma)2(H2O)2]CF3SO3 complex (1b) was inadvertently isolated and characterized crystallographically, and the monomaltolato species [Ru(ma)(N-MeIm)4][CF3SO3]2 (6) was also isolated and characterized. In vitro antiproliferatory activity of complexes 2−6 against human breast cancer cells (MDA-MB-435S) was tested using an MTT assay: 4 and 5 exhibit the lowest IC50 values, ~5 and ~15 µmol/L, respectively, whereas cisplatin exhibits an IC50 value of ~35 µmol/L against this cell line.
Theoretical investigation of the conformational intricacies and thermodynamic functions of noradrenaline
Authors: Lee DongJin R. , Galant Natalie J. , Lee Donghoon M. , Dawson Sean S.H. , Ding Vanna Z.Y. , Setiadi David H. , Viskolcz Bela , Csizmadia Imre G.
Published: August 2011

Noradrenaline is a neurotransmitter that is involved in various psychological processes. In the neurotransmission process, noradrenaline binds to an adrenergic receptor by forming a complex of hydrogen bonds between its two catechol ring hydroxyl groups and the amino acid residues of adrenergic receptors. Although the two catechol ring hydroxyl groups play a crucial role in making hydrogen bonds to the binding site of the adrenergic receptor, the contribution of the catechol ring hydroxyl groups to the intramolecular stability that may affect docking has not been fully studied. To reveal the specific role that the catechol ring hydroxyl groups might play in stabilizing noradrenaline, the quantum chemical computations of geometry optimization and thermodynamic functions of N-protonated noradrenaline conformers were performed at both the B3LYP/6–31G(d,p) and G3MP2B3 levels of theory, using the Gaussian 03 program. The results were compared with those of N-protonated β-hydroxy-β-phenylethylamine, which is identical to noradrenaline except it lacks two catechol ring hydroxyl groups. For the first time, post-Hartree–Fock computations were used to obtain thermodynamic functions to establish relative stabilities of all possible conformers of N-protonated noradrenaline. In this study, 18 distinct structures of N-protonated noradrenaline were revealed, and the catechol ring hydroxyl groups were found to affect noradrenaline stability positively or negatively depending on the conformational orientations. On the basis of available experimental results, the issue that the least stable conformation of two catechol ring hydroxyl groups may be involved in the docking process has been raised. These findings may be useful in synthesis of derivatives of noradrenaline in drug design.
Adjacent land-use affects amphibian community composition and species richness in managed forests in New Brunswick, Canada
Authors: Jacobs Lee , Houlahan Jeff E.
Published: August 2011

Here, we examine the effects of adjacent land use in a managed forest on pond-breeding amphibian species richness and community composition at 34 New Brunswick, Canada, ponds. Amphibian species richness was negatively correlated with the proportion of roads, precommercial thinning, and hardwood forest and positively correlated with the proportion of wetlands in adjacent lands. These land-use effects peak at 180 m from the ponds. Road density was negatively correlated with Lithobates catesbeiana and Lithobates septentrionalis presence. Precommercial thinning was negatively correlated with Ambystoma spp. presence and positively correlated with Anaxyrus americanus presence. Wetlands were positively correlated with L. septentrionalis and Notopthalamus viridescens presence. Correlations were also found between water table height and A. americanus, Lithobates palustris , and Ambystoma spp. presence. In addition, L. catesbeiana and N. viridescens presence–absence was positively correlated with the proportion of mature and overmature forest on the landscape (at scales of 500 and 1000 m, respectively). Lastly, the proportion of regenerating and sapling forest on the landscape was negatively correlated with L. palustris presence–absence but, by contrast, was positively correlated with A. americanus. These results suggest that the effects of adjacent land use may significantly impact amphibian populations in managed eastern Canadian forests.
A system of nonlinear simultaneous equations for crown length and crown radius for the forest dynamics model SORTIE-ND
Authors: Sattler Derek F. , LeMay Valerie
Published: August 2011

A system of equations was developed to predict crown length (CL) and crown radius (CRAD) for trees in structurally complex stands. The equations address two problems that often arise in crown allometry. First, relationships between the main stem and the crown are likely to change with intertree competition. Therefore, explicit measures of density were used along with main stem measurements as explanatory variables. Second, the physiological relationship between CL and CRAD is often overlooked when modeling crowns. This relationship is incorporated through the use of a simultaneous system of equations. Parameters were estimated using nonlinear three-stage least squares (N3SLS) in which first-stage equation estimates of CRAD are used to estimate CL and vice versa in the second and third stages of N3SLS. The equations were fitted and validated for four species: lodgepole pine (Pinus contorta Douglas ex Louden var. latifolia Engelm. ex S. Watson), hybrid spruce (Picea engelmannii Parry ex Engelm. × P. glauca (Moench) Voss), Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. glauca (Beissn.) Franco), and trembling aspen (Populus tremuloides Michx.). The intent is to use the equations as alternatives to the crown equations in the spatially explicit forest growth model SORTIE-ND that use only main stem variables in estimating crowns over time.
Deriving forest canopy fuel parameters for loblolly pine forests in eastern Texas
Authors: Agca Muge , Popescu Sorin C. , Harper Clinton W.
Published: August 2011

Crown fires, the fastest spreading of all forest fires, can occur in any forest type throughout the world. The overall aim of this study was to estimate forest canopy fuel parameters including canopy bulk density and canopy base height for loblolly pines ( Pinus taeda L.) at the plot level using both allometric equations and CrownMass/FMAPlus software. Allometric equation results were compared with the CrownMass outputs for validation. According to our results, the calculated average canopy bulk density values, across all 50 plots, were 0.18 and 0.07 kg/m3 for the allometric equation and the CrownMass program, respectively. Lorey’s mean height approach was used in this study to calculate canopy base height at the plot level. The average height values of canopy base height obtained from the Lorey height approach was 10.6 m and from the CrownMass program was 9.1 m. The results obtained for the two methods are relatively close to each other, with the estimate of canopy base height being 1.16 times larger than the CrownMass value. This study provides a practical method for quantifying these parameters and making them directly available to fire managers. The accuracy of these parameters is very important for realistic predictions of wildfire initiation and growth.
Temporal dynamics of nonstructural carbohydrates and xylem growth inPinus sylvestrisexposed to drought
Authors: Oberhuber Walter , Swidrak Irene , Pirkebner Daniela , Gruber Andreas
Published: August 2011

Wood formation requires a continuous supply of carbohydrates for structural growth and metabolism. In the montane belt of the central Austrian Alps, we monitored the temporal dynamics of xylem growth and nonstructural carbohydrates (NSC) in stem sapwood of Scots pine ( Pinus sylvestris L.) during the growing season of 2009, which was characterized by exceptional soil dryness within the study area. Soil water content dropped below 10% at the time of maximum xylem growth at the end of May. Histological analyses have been used to describe cambial activity and xylem growth. Determination of NSC was performed using specific enzymatic assays revealing that total NSC ranged from 0.8% to 1.7% dry matter throughout the year. Significant variations (P < 0.05) of the size of the NSC pool were observed during the growing season. Starch showed persistent abundance throughout the year, reaching a maximum shortly before onset of late wood formation in mid-July. Seasonal dynamics of NSC and xylem growth suggest that (i) high sink activity occurred at the start of the growing season in spring and during late wood formation in summer and (ii) there was no particular shortage in NSC, which caused P. sylvestris to draw upon stem reserves more heavily during the drought in 2009.
Linking climate, gross primary productivity, and site index across forests of the western United States
Authors: Weiskittel Aaron R. , Crookston Nicholas L. , Radtke Philip J.
Published: August 2011

Assessing forest productivity is important for developing effective management regimes and predicting future growth. Despite some important limitations, the most common means for quantifying forest stand-level potential productivity is site index (SI). Another measure of productivity is gross primary production (GPP). In this paper, SI is compared with GPP estimates obtained from 3-PG and NASA’s MODIS satellite. Models were constructed that predict SI and both measures of GPP from climate variables. Results indicated that a nonparametric model with two climate-related predictor variables explained over 68% and 76% of the variation in SI and GPP, respectively. The relationship between GPP and SI was limited (R2 of 36%–56%), while the relationship between GPP and climate (R2 of 76%–91%) was stronger than the one between SI and climate (R2 of 68%–78%). The developed SI model was used to predict SI under varying expected climate change scenarios. The predominant trend was an increase of 0–5 m in SI, with some sites experiencing reductions of up to 10 m. The developed model can predict SI across a broad geographic scale and into the future, which statistical growth models can use to represent the expected effects of climate change more effectively.
APPROXIMATING THE EFFECT OF VAN DER WAALS FORCE ON THE INSTABILITY OF ELECTROSTATIC NANO-CANTILEVERS
Authors: KOOCHI ALI , NOGHREHABADI AMINREZA , ABADYAN MOHAMADREZA
Published: August 2011

Beam-type nano-electromechanical system (NEMS) is one of the most components in constructing nano-devices. Herein, a distributed parameter model is used to study the influence of van der Waals (vdW) attraction on the pull-in performance of the cantilever NEMS. Homotopy perturbation method (HPM) is applied to solve the nonlinear governing equation of the actuators in the form of convergent series. Moreover, analytical results are compared with those of numerical method as well as a lumped parameter model. The pull-in voltage and critical cantilever tip deflection of NEMS are determined. Results depict that vdW attraction decreases the pull-in deflection and voltage of the NEMS. On the other hand, the fringing field increases the pull-in deflection while decreases the pull-in voltage of the system. The analytical results have good agreement with numerical results and those available in the literature.
GLOBAL WEAK SOLUTIONS FOR THE RELATIVISTIC WATERBAG CONTINUUM
Authors: BESSE NICOLAS
Published: August 2011

In this paper we consider the relativistic waterbag continuum which is a useful PDE for collisionless kinetic plasma modeling recently developed in Ref. 11. The waterbag representation of the statistical distribution function of particles can be viewed as a special class of exact weak solution of the Vlasov equation, allowing to reduce this latter into a set of hydrodynamic equations (with the complexity of a multi-fluid model) while keeping its kinetic features (Landau damping and nonlinear resonant wave-particle interaction). These models are very promising because they are very useful for analytical theory and numerical simulations of laser-plasma and gyrokinetic physics.10–16, 56, 57 The relativistic waterbag continuum is derived from two phase-space variable reductions of the relativistic Vlasov–Maxwell equations through the existence of two underlying exact invariants, one coming from physics properties of the dynamics is the canonical transverse momentum, and the second, named the "water-bag" and coming from geometric property of the phase-space is just the direct consequence of the Liouville Theorem. In this paper we prove the existence and uniqueness of global weak entropy solutions of the relativistic waterbag continuum. Existence is based on vanishing viscosity method and bounded variations (BV) estimates to get compactness while proof of uniqueness relies on kinetic formulation of the relativistic waterbag continuum and the associated kinetic entropy defect measure.
EXISTENCE RESULTS FOR A POLYMER MELT WITH AN EVOLVING NATURAL CONFIGURATION
Authors: DJOKO J. K. , REDDY B. D.
Published: August 2011

We consider a set of equations governing the behavior of a polymer melt which is modeled as a viscoelastic fluid possessing a natural, or stress-free state. The natural configuration is characterized through a symmetric, proper orthogonal intermediate deformation tensor, analogous to the left Cauchy–Green deformation tensor in continuum mechanics. This tensor is required to satisfy an evolution equation. It is shown that the constraint that the intermediate tensor be proper orthogonal is satisfied provided that its initial value satisfies this constraint. Local existence and uniqueness of solutions to the initial boundary value problem of the resulting viscoelastic fluid system are established. It is also shown that the local solutions can be extended globally provided that the data are small enough.
“Liking” and “wanting” of sweet and oily food stimuli as affected by high-fat diet-induced obesity, weight loss, leptin, and genetic predisposition
Authors: Shin Andrew C. , Townsend R. Leigh , Patterson Laurel M. , Berthoud Hans-Rudolf
Published: August 2011

Cross-sectional studies in both humans and animals have demonstrated associations between obesity and altered reward functions at the behavioral and neural level, but it is unclear whether these alterations are cause or consequence of the obese state. Reward behaviors were quantified in male, outbred Sprague-Dawley (SD) and selected line obesity-prone (OP) and obesity-resistant (OR) rats after induction of obesity by high-fat diet feeding and after subsequent loss of excess body weight by chronic calorie restriction. As measured by the brief access lick and taste-reactivity paradigms, both obese SD and OP rats “liked” low concentrations of sucrose and corn oil less, but “liked” the highest concentrations more, compared with lean rats, and this effect was fully reversed by weight loss in SD rats. Acute food deprivation was unable to change decreased responsiveness to low concentrations but eliminated increased responsiveness to high concentrations in obese SD rats, and leptin administration in weight-reduced SD rats shifted concentration-response curves toward that seen in the obese state in the brief access lick test. “Wanting” and reinforcement learning as assessed in the incentive runway and progressive ratio lever-pressing paradigms was paradoxically decreased in both obese (compared with lean SD rats) and OP (compared with OR rats). Thus, reversible, obesity-associated, reduced “liking” and “wanting” of low-calorie foods in SD rats suggest a role for secondary effects of the obese state on reward functions, while similar differences between select lines of OP and OR rats before induction of obesity indicate a genetic component.
Chronic heart failure selectively induces regional heterogeneity of insulin-responsive glucose transporters
Authors: Ware Bruce , Bevier Marie , Nishijima Yoshinori , Rogers Suzanne , Carnes Cynthia A. , Lacombe Véronique A.
Published: August 2011

Glucose uptake across the sarcolemma is regulated by a family of membrane proteins called glucose transporters (GLUTs), which includes GLUT4 (the major cardiac isoform) and GLUT12 (a novel, second insulin-sensitive isoform). Potential regional patterns in glucose transport across the cardiac chambers have not been examined; thus, we hypothesized that insulin-responsive GLUT4 and -12 protein and gene expression would be chamber specific in healthy subjects and during chronic heart failure (HF). Using a canine model of tachypacing-induced, progressive, chronic HF, total GLUT protein and messenger RNA in both ventricles and atria (free wall and appendage) were investigated by immunoblotting and real-time PCR. In controls, GLUT4, but not GLUT12, protein content was significantly higher in the atria compared with the ventricles, with the highest content in the right atrium (RA; P < 0.001). GLUT4 and GLUT12 mRNA levels were similar across the cardiac chambers. During chronic HF, GLUT4 and GLUT12 protein content was highest in the left ventricle (LV; by 2.5- and 4.2-fold, respectively, P < 0.01), with a concomitant increase in GLUT4 and GLUT12 mRNA ( P < 0.001). GLUT4, but not GLUT12, protein content was decreased in RA during chronic HF ( P = 0.001). In conclusion, GLUT4 protein was differentially expressed across the chambers in the healthy heart, and this regional pattern was reversed during HF. Our data suggest that LV was the primary site dependent on both GLUT4 and GLUT12 during chronic HF. In addition, the paradoxical decrease in GLUT4 content in RA may induce perturbations in atrial energy production during chronic HF.