bluuebunny/crossref_metadata_2025_split huggingface dataset:
Factors Affecting the Initial Adhesion and Retention of the Plant Pathogen Xylella fastidiosa in the Foregut of an Insect Vector
Authors: Killiny Nabil , Almeida Rodrigo P. P. 
Published: November 2013

ABSTRACT

Vector transmission of bacterial plant pathogens involves three steps: pathogen acquisition from an infected host, retention within the vector, and inoculation of cells into susceptible tissue of an uninfected plant. In this study, a combination of plant and artificial diet systems were used to determine the importance of several genes on the initial adhesion and retention of the bacterium
Xylella fastidiosa
to an efficient insect vector. Mutant strains included fimbrial (
fimA
and
pilB
) and afimbrial (
hxfA
and
hxfB
) adhesins and three loci involved in regulatory systems (
rpfF
,
rpfC
, and
cgsA
). Transmission assays with variable retention time indicated that HxfA and HxfB were primarily important for early adhesion to vectors, while FimA was necessary for both adhesion and retention. The long pilus protein PilB was not deficient in initial adhesion but may be important for retention. Genes upregulated under the control of
rpfF
are important for both initial adhesion and retention, as transmission rates of this mutant strain were initially low and decreased over time, while disruption of
rpfC
and
cgsA
yielded trends similar to that shown by the wild-type control. Because induction of an
X. fastidiosa
transmissible state requires pectin, a series of experiments were used to test the roles of a polygalacturonase (
pglA
) and the pectin and galacturonic acid carbohydrates on the transmission of
X. fastidiosa
. Results show that galacturonic acid, or PglA activity breaking pectin into its major subunit (galacturonic acid), is required for
X. fastidiosa
vector transmission using an artificial diet system. This study shows that early adhesion and retention of
X. fastidiosa
are mediated by different factors. It also illustrates that the interpretation of results of vector transmission experiments, in the context of vector-pathogen interaction studies, is highly dependent on experimental design.
Role of the Trypanosoma brucei HEN1 Family Methyltransferase in Small Interfering RNA Modification
Authors: Shi Huafang , Barnes Rebecca L. , Carriero Nicholas , Atayde Vanessa D. , Tschudi Christian , Ullu Elisabetta 
Published: November 2013

ABSTRACT

Parasitic protozoa of the flagellate order Kinetoplastida represent one of the deepest branches of the eukaryotic tree. Among this group of organisms, the mechanism of RNA interference (RNAi) has been investigated in
Trypanosoma brucei
and to a lesser degree in
Leishmania
(
Viannia
) spp. The pathway is triggered by long double-stranded RNA (dsRNA) and in
T. brucei
requires a set of five core genes, including a single Argonaute (AGO) protein,
T. brucei
AGO1 (
Tb
AGO1). The five genes are conserved in
Leishmania
(
Viannia
) spp. but are absent in other major kinetoplastid species, such as
Trypanosoma cruzi
and
Leishmania major
. In
T. brucei
small interfering RNAs (siRNAs) are methylated at the 3′ end, whereas
Leishmania
(
Viannia
) sp. siRNAs are not. Here we report that
T. brucei
HEN1, an ortholog of the metazoan HEN1 2′-
O
-methyltransferases, is required for methylation of siRNAs. Loss of
Tb
HEN1 causes a reduction in the length of siRNAs. The shorter siRNAs in
hen1
−/−
parasites are single stranded and associated with
Tb
AGO1, and a subset carry a nontemplated uridine at the 3′ end. These findings support a model wherein
Tb
HEN1 methylates siRNA 3′ ends after they are loaded into
Tb
AGO1 and this methylation protects siRNAs from uridylation and 3′ trimming. Moreover, expression of
Tb
HEN1 in
Leishmania
(
Viannia
)
panamensis
did not result in siRNA 3′ end methylation, further emphasizing mechanistic differences in the trypanosome and
Leishmania
RNAi mechanisms.
Imaging Early Pathogenesis of Bubonic Plague: Are Neutrophils Commandeered for Lymphatic Transport of Bacteria?
Authors: Bland David M. , Anderson Deborah M. 
Published: November 2013

ABSTRACT

Vector-borne infections begin in the dermis when a pathogen is introduced by an arthropod during a blood meal. Several barriers separate an invading pathogen from its replicative niche, including phagocytic cells in the dermis that activate immunity by engulfing would-be pathogens and migrating to the lymph node. In addition, neutrophils circulating in the blood are rapidly recruited when the dermal barriers are penetrated. For flea-borne disease, no insect-encoded immune-suppressive molecules have yet been described that might influence the establishment of infection, leaving the bacteria on their own to defend against the mammalian immune system. Shortly after a flea transmits
Yersinia pestis
to a mammalian host, the bacteria are transported to the lymph node, where they grow logarithmically and later spread systemically. Even a single cell of
Y. pestis
can initiate a lethal case of plague. In their article, J. G. Shannon et al. [mBio 4(5):e00170-13, 2013, doi:10.1128/mBio.00170-13] used intravital microscopy to visualize trafficking of
Y. pestis
in transgenic mice
in vivo
, which allowed them to examine interactions between bacteria and specific immune cells. Bacteria appeared to preferentially interact with neutrophils but had no detectable interactions with dendritic cells. These findings suggest that
Y. pestis
infection of neutrophils not only prevents their activation but may even result in their return to circulation and migration to distal sites.
Fine-grained semi-supervised labeling of large shape collections
Authors: Huang Qi-Xing , Su Hao , Guibas Leonidas 
Published: November 2013

In this paper we consider the problem of classifying shapes within a given category (e.g., chairs) into finer-grained classes (e.g., chairs with arms, rocking chairs, swivel chairs). We introduce a multi-label (i.e., shapes can belong to multiple classes) semi-supervised approach that takes as input a large shape collection of a given category with associated sparse and noisy labels, and outputs cleaned and complete labels for each shape. The key idea of the proposed approach is to jointly learn a distance metric for each class which captures the underlying geometric similarity within that class, e.g., the distance metric for swivel chairs evaluates the global geometric resemblance of chair bases. We show how to achieve this objective by first geometrically aligning the input shapes, and then learning the class-specific distance metrics by exploiting the feature consistency provided by this alignment. The learning objectives consider both labeled data and the mutual relations between the distance metrics. Given the learned metrics, we apply a graph-based semi-supervised classification technique to generate the final classification results.
In order to evaluate the performance of our approach, we have created a benchmark data set where each shape is provided with a set of ground truth labels generated by Amazon's Mechanical Turk users. The benchmark contains a rich variety of shapes in a number of categories. Experimental results show that despite this variety, given very sparse and noisy initial labels, the new method yields results that are superior to state-of-the-art semi-supervised learning techniques.
OATP1A/1B Transporters Affect Irinotecan and SN-38 Pharmacokinetics and Carboxylesterase Expression in Knockout and Humanized Transgenic Mice
Authors: Iusuf Dilek , Ludwig Marion , Elbatsh Ahmed , van Esch Anita , van de Steeg Evita , Wagenaar Els , van der Valk Martin , Lin Fan , van Tellingen Olaf , Schinkel Alfred H. 
Published: November 2013

Abstract
Organic anion-transporting polypeptides (OATP) mediate the hepatic uptake of many drugs, thus codetermining their clearance. Impaired hepatic clearance due to low-activity polymorphisms in human OATP1B1 may increase systemic exposure to SN-38, the active and toxic metabolite of the anticancer prodrug irinotecan. We investigated the pharmacokinetics and toxicity of irinotecan and SN-38 in Oatp1a/1b-null mice: Plasma exposure of irinotecan and SN-38 was increased 2 to 3-fold after irinotecan dosing (10 mg/kg, i.v.) compared with wild-type mice. Also, liver-to-plasma ratios were significantly reduced, suggesting impaired hepatic uptake of both compounds. After 6 daily doses of irinotecan, Oatp1a/1b-null mice suffered from increased toxicity. However, Oatp1a/1b-null mice had increased levels of carboxylesterase (Ces) enzymes, which caused higher conversion of irinotecan to SN-38 in plasma, potentially complicating pharmacokinetic analyses. Ces inhibitors blocked this increased conversion. Interestingly, liver-specific humanized OATP1B1 and OATP1B3 transgenic mice had normalized hepatic expression of Ces1 genes. While irinotecan liver-to-plasma ratios in these humanized mice were similar to those in Oatp1a/1b-null mice, SN-38 liver-to-plasma ratios returned to wild-type levels, suggesting that human OATP1B proteins mediate SN-38, but not irinotecan uptake in vivo. Upon direct administration of SN-38 (1 mg/kg, i.v.), Oatp1a/1b-null mice had increased SN-38 plasma levels, lower liver concentrations, and decreased cumulative biliary excretion of SN-38. Mouse Oatp1a/1b transporters have a role in the plasma clearance of irinotecan and SN-38, whereas human OATP1B transporters may only affect SN-38 disposition. Oatp1a/1b-null mice have increased expression and activity of Ces1 enzymes, whereas humanized mice provide a rescue of this phenotype. Mol Cancer Ther; 13(2); 492–503. ©2013 AACR.
Myocardial Strain Analysis by 2-Dimensional Speckle Tracking Echocardiography Improves Diagnostics of Coronary Artery Stenosis in Stable Angina Pectoris
Authors: Biering-Sørensen Tor , Hoffmann Soren , Mogelvang Rasmus , Zeeberg Iversen Allan , Galatius Søren , Fritz-Hansen Thomas , Bech Jan , Jensen Jan Skov 
Published: November 2013

Background—
Two-dimensional strain echocardiography detects early signs of left ventricular dysfunction; however, it is unknown whether myocardial strain analysis at rest in patients with suspected stable angina pectoris predicts the presence of coronary artery disease (CAD).

Methods and Results—

In total, 296 consecutive patients with clinically suspected stable angina pectoris, no previous cardiac history, and normal left ventricular ejection fraction were included. All patients were examined by 2-dimensional strain echocardiography, exercise ECG, and coronary angiography. Two-dimensional strain echocardiography was performed in the 3 apical projections. Peak regional longitudinal systolic strain was measured in 18 myocardial sites and averaged to provide global longitudinal peak systolic strain. Duke score, including ST-segment depression, chest pain, and exercise capacity, was used as the outcome of the exercise test. Patients with an area stenosis ≥70% in ≥1 epicardial coronary artery were categorized as having significant CAD (n=107). Global longitudinal peak systolic strain was significantly lower in patients with CAD compared with patients without (17.1±2.5% versus 18.8±2.6%;
P
<0.001) and remained an independent predictor of CAD after multivariable adjustment for baseline data, exercise test, and conventional echocardiography (odds ratio, 1.25 [
P
=0.016] per 1% decrease). Area under receiver operating characteristic curve for exercise test and global longitudinal peak systolic strain in combination was significantly higher than that for exercise test alone (0.84 versus 0.78;
P
=0.007). Furthermore, impaired regional longitudinal systolic strain identifies which coronary artery is stenotic.

Conclusions—
In patients with suspected stable angina pectoris, global longitudinal peak systolic strain assessed at rest is an independent predictor of significant CAD and significantly improves the diagnostic performance of exercise test. Furthermore, 2-dimensional strain echocardiography seems capable of identifying high-risk patients.
Lower Hospital Volume Is Associated With Higher In-Hospital Mortality in Patients Undergoing Primary Percutaneous Coronary Intervention for ST-Segment–Elevation Myocardial Infarction
Authors: Kontos Michael C. , Wang Yongfei , Chaudhry Sarwat I. , Vetrovec George W. , Curtis Jeptha , Messenger John 
Published: November 2013

Background—
Current guidelines recommend >36 primary percutaneous coronary interventions (PCIs) per hospital per year. Whether these standards remain valid when routine coronary stenting and newer pharmacological agents are used is unclear.

Methods and Results—

We analyzed patients who underwent primary PCI from July 2006 through June 2009 included in the CathPCI Registry. Hospitals were separated into 3 groups: low (≤36 primary PCIs/y, current guideline recommendation), intermediate (>36–60 primary PCIs/y), and high volume (>60 primary PCIs/y). In-hospital mortality and door-to-balloon time were examined for each group. A total of 87 324 patient visits for 86 044 patients from 738 hospitals were included. There were 278 low- (38%), 236 (32%) intermediate-, and 224 (30%) high-volume hospitals. The majority of patients with primary PCI (54%) were treated at high-volume hospitals, with 15% at low-volume hospitals. Unadjusted mortality was significantly higher in low-volume hospitals compared with high-volume hospitals (5.6% versus 4.8%;
P
<0.001), which was maintained after multivariate adjustment (1.20; 95% confidence interval, 1.08–1.33;
P
=0.001). In contrast, mortality was not significantly different between intermediate-volume and high-volume hospitals (4.8% versus 4.8%; adjusted odds ratio, 1.02; 95% confidence interval, 0.94–1.11;
P
=0.61). Door-to-balloon times were significantly shorter in high-volume hospitals compared with low-volume hospitals (median, 72 minutes; interquartile range, [53–91] versus 77 [57–100] minutes;
P
<0.0001).

Conclusions—
Higher annual hospital volume of primary PCI continues to be associated with lower mortality, with higher mortality in hospitals performing ≤36 primary PCIs/y.
On the Correspondence between Mean Forecast Errors and Climate Errors in CMIP5 Models
Authors: Ma H.-Y. , Xie S. , Klein S. A. , Williams K. D. , Boyle J. S. , Bony S. , Douville H. , Fermepin S. , Medeiros B. , Tyteca S. , Watanabe M. , Williamson D. 
Published: November 2013

Abstract
The present study examines the correspondence between short- and long-term systematic errors in five atmospheric models by comparing the 16 five-day hindcast ensembles from the Transpose Atmospheric Model Intercomparison Project II (Transpose-AMIP II) for July–August 2009 (short term) to the climate simulations from phase 5 of the Coupled Model Intercomparison Project (CMIP5) and AMIP for the June–August mean conditions of the years of 1979–2008 (long term). Because the short-term hindcasts were conducted with identical climate models used in the CMIP5/AMIP simulations, one can diagnose over what time scale systematic errors in these climate simulations develop, thus yielding insights into their origin through a seamless modeling approach.
The analysis suggests that most systematic errors of precipitation, clouds, and radiation processes in the long-term climate runs are present by day 5 in ensemble average hindcasts in all models. Errors typically saturate after few days of hindcasts with amplitudes comparable to the climate errors, and the impacts of initial conditions on the simulated ensemble mean errors are relatively small. This robust bias correspondence suggests that these systematic errors across different models likely are initiated by model parameterizations since the atmospheric large-scale states remain close to observations in the first 2–3 days. However, biases associated with model physics can have impacts on the large-scale states by day 5, such as zonal winds, 2-m temperature, and sea level pressure, and the analysis further indicates a good correspondence between short- and long-term biases for these large-scale states. Therefore, improving individual model parameterizations in the hindcast mode could lead to the improvement of most climate models in simulating their climate mean state and potentially their future projections.
Measured and Parameterized Energy Fluxes Estimated for Atlantic Transects of R/V Polarstern
Authors: Bumke Karl , Schlundt Michael , Kalisch John , Macke Andreas , Kleta Henry 
Published: November 2013

Abstract
Sensible and latent heat fluxes were estimated from turbulence measurements gathered during several Atlantic Ocean transects of the research vessel (R/V) Polarstern. The inertial dissipation method was used to analyze the data. Resulting bulk transfer coefficients were then applied to the data from the ship’s meteorological system to get continuous time series of the heat fluxes. Combined with the measured downward solar and longwave radiation fluxes it allows for an estimate of the total energy budget at the air–sea interface. Comparing these parameterized energy fluxes to those based on the Coupled Ocean–Atmosphere Response Experiment, version 3 (COARE3.0), bulk flux algorithm shows very strong agreement.
Salivary testosterone measurement by liquid chromatography tandem mass spectrometry in adult males and females
Authors: Keevil BG , MacDonald P , Macdowall W , Lee DM , Wu FCW ,   the NATSAL Team
Published: November 2013

Background Salivary testosterone (Sal-T) may be a useful surrogate of serum free testosterone. The study aims were to use a novel liquid chromatography tandem mass spectrometry (LC-MS/MS) assay to determine whether Sal-T concentrations accurately reflect Sal-T concentrations in both sexes and to investigate practical aspects of sample collection. Methods Saliva and serum samples were collected in 104 male and 91 female subjects. A more sensitive LC-MS/MS assay was developed to enable Sal-T quantitation in the low concentrations found in females. Saliva (200 µL) was extracted with 1 mL of methyl- tert-butyl ether following the addition of D5-testosterone. Quantitation was performed using a Waters TQ-S mass spectrometer. Results The assay achieved a lower limit of quantification of 5 pmol/L, sufficiently sensitive to measure testosterone in female saliva. Sal-T showed a diurnal variation but samples taken at weekly and monthly intervals showed no significant differences. Sal-T was stable at ambient temperature for up to 5 days, after freeze-thawing and 3 years frozen storage. Reference intervals for Sal-T were 93–378 pmol/L in males and 5–46 pmol/L in females. Sal-T correlated significantly with serum calculated free-T in males ( r = 0.71, P < 0.001) and in females ( r = 0.39, P < 0.001). Conclusions These results confirm that testosterone can be reliably and accurately measured by LC-MS/MS in both adult male and female saliva samples. These results lay the foundation for further exploration of the clinical application of Sal- T as a reliable alternative to serum testosterone in the diagnosis and management of androgen disorders and assessment of androgen status in clinical research.
Clinical and echocardiographic predicators of postoperative atrial fibrillation
Authors: Elawady Mohamed Ahmed , Bashandy Mohamed 
Published: November 2013

Background Postoperative atrial fibrillation is the most common arrhythmia after coronary artery bypass grafting, with a reported incidence of 10% to 60%. Preoperative clinical and echocardiographic data, especially the atrial electromechanical interval, predict postoperative atrial fibrillation in elective coronary artery bypass patients. Methods A prospective study evaluated preoperative clinical and echocardiographic data in 192 patients who underwent elective coronary artery bypass from 2010 to 2012. Results 18 (9.37%) patients developed postoperative atrial fibrillation. Compared to patients without postoperative atrial fibrillation, these 18 had significantly longer intensive care unit and hospital stays, they were significantly older (58.62 ± 10.02 vs. 53.22 ± 8.23 years; p = 0.02), with a larger left atrial volume (83.39 ± 8.31 vs. 55.47 ± 8.37 cm3, p = 0.001), longer atrial electromechanical interval (133.67 ± 8.15 vs. 98.05 ± 6.71 ms p < 0.0001), and lower tissue Doppler imaging systolic velocity wave amplitude (6.6 ± 1 vs. 9.4 ± 2.2 cm·s−1; p = 0.001); they also had a higher prevalence of hypertension (61.11% vs. 38.5%; p = 0.04). Using 115 ms as the cutoff value of atrial electromechanical interval enabled us to detect patients who developed postoperative atrial fibrillation with 100% sensitivity, 77% specificity, 78% positive predictive value, and 100% negative predictive value. Conclusion Older hypertensive patients are at higher risk of developing postoperative atrial fibrillation. Preoperative measurement of atrial electromechanical interval by tissue Doppler echocardiography is a useful predictor of postoperative atrial fibrillation in coronary artery bypass patients.
Differential release kinetics of cardiac biomarkers in off-pump coronary bypass
Authors: Singh Satyajit , Kapoor Aditya , Agarwal Surendra Kumar , Pande Shantanu , Sinha Archana , Rai Himanshu , Kumar Sudeep , Tewari Satyendra , Garg Naveen , Majumdar Gauranga , Chandra Bipin , Goel Pravin K 
Published: November 2013

Background Differential release kinetics of the cardiac biomarkers (B-type natriuretic peptide, troponin I, and creatine kinase-MB) following off-pump coronary artery bypass are not well characterized. Methods Biomarker levels were assessed at 6, 24, 48 h, and 1 month preoperatively, in 80 patients who underwent off-pump coronary artery bypass. Results All biomarkers increased within 6 h of surgery. Peak B-type natriuretic peptide levels occurred at 24–48 h in 96% of patients, but only two-thirds had peak troponin I and creatine kinase-MB levels at this time, reflecting different release patterns. Levels of all biomarkers declined within 48 h, but 42% of patients still had B-type natriuretic peptide >100 pg·mL−1 at 1 month. Those with baseline B-type natriuretic peptide > 100 pg·mL−1 had a lower left ventricular ejection fraction (43.6% vs. 55.6%, p < 0.01) and longer inotropic (43.8 vs. 31.4 h, p = 0.03) and ventilator support (34 vs. 25.5 h, p = 0.04) than those with lower levels. B-type natriuretic peptide levels correlated positively with angiographic Syntax score ( p = 0.02) and negatively with left ventricular ejection fraction ( p < 0.001). Only baseline B-type natriuretic peptide predicted the durations of inotropic support ( p = 0.01) and ventilation ( p = 0.02). Postoperative B-type natriuretic peptide at 6, 24, and 48 h and delta B-type natriuretic peptide were significant predictors of mean ventilation time. Conclusion Even in patients undergoing off-pump surgery, there is significant natriuretic peptide and myocardial enzyme release. Only B-type natriuretic peptide levels had an association with postoperative variables.