bluuebunny/crossref_metadata_2025_split huggingface dataset:
Substrate Competition Studies Using Whole-Cell Accumulation Assays with the Major Tripartite Multidrug Efflux Pumps of
Escherichia coli
Authors: Elkins Christopher A. , Mullis Lisa B. 
Published: January 2007

ABSTRACT

AcrAB-TolC is the major, constitutively expressed tripartite multidrug efflux system in
Escherichia coli
that recognizes various structurally unrelated molecules, including many antibiotics, dyes, and steroids. The AcrB inner membrane pump portion of the efflux system has been shown in recent structural studies to bind substrates at multiple sites, suggesting that particular substrate “sets” may compete for efflux by interfering with a certain binding site(s). However, our data indicate that the general structural class does not appear to dictate a particular substrate binding site that can be competitively inhibited in whole cells. In our study, substrate competition failed to increase cell-associated levels of steroids or dyes to levels characteristic of AcrB- or AcrB/EmrAB-deficient genomic mutants or achieved with the pump inhibitor carbonyl cyanide
m
-chlorophenylhydrazone. In addition, this general observation was sustained even with (i) a cocktail containing seven-pump substrates supplied slightly below their respective wild-type MIC levels, (ii) competing drug substrates of the same structural class (steroids or macrolides), and (iii) hyper-MIC levels of the exogenously supplied agents. Thus, this pump system (and possibly EmrAB-TolC) may have an extraordinary capacity to simultaneously handle multiple-drug substrates that is not necessarily reflected in MIC analyses. In addition, our study has extended the range of substrates recognized by the AcrAB- and EmrAB-TolC systems.
Azithromycin Selectively Reduces Tumor Necrosis Factor Alpha Levels in Cystic Fibrosis Airway Epithelial Cells
Authors: Cigana Cristina , Assael Baroukh Maurice , Melotti Paola 
Published: January 2007

ABSTRACTAzithromycin (AZM) ameliorates lung function in cystic fibrosis (CF) patients. This macrolide has been suggested to have anti-inflammatory properties as well as other effects potentially relevant for therapy of CF. In this study, we utilized three CF (IB3-1, 16HBE14o- AS3, and 2CFSMEo-) and two isogenic non-CF (C38 and 16HBE14o- S1) airway epithelial cell lines to investigate whether AZM could reduce tumor necrosis factor alpha (TNF-α) mRNA and protein levels by real-time quantitative PCR analysis and an enzyme-linked immunosorbent assay (ELISA), respectively. We studied the effects on the DNA binding of NF-κB and specificity protein 1 (Sp1) by an ELISA. Non-CF cells express significantly lower TNF-α mRNA and protein levels than an isogenic CF cell line. In CF cells, AZM treatment causes a 30% reduction of TNF-α mRNA levels (P< 0.05) and a 45% decrease in TNF-α secretion (P< 0.05), reaching approximately the levels of the untreated isogenic non-CF cells. In CF cells, NF-κB and Sp1 DNA binding activities were also significantly decreased (about 45 and 60%, respectively;P< 0.05) after AZM treatment. Josamycin, a macrolide lacking clinically described anti-inflammatory effects, was ineffective. Finally, AZM did not alter the mRNA expression levels of interleukin-6, a proinflammatory molecule not differentially expressed in CF and isogenic non-CF cells. The results of our study support the anti-inflammatory activities of this macrolide, since we show that AZM reduced the levels of TNF-α and propose inhibitions of NF-κB and Sp1 DNA binding as possible mechanisms of this effect.
Molecular Analysis of the Subgingival Microbiota in Health and Disease
Authors: Ledder Ruth G. , Gilbert Peter , Huws Sharon A. , Aarons Leon , Ashley Martin P. , Hull Peter S. , McBain Andrew J. 
Published: January 2007

ABSTRACT

This investigation provides molecular analyses of the periodontal microbiota in health and disease. Subgingival samples from 47 volunteers with healthy gingivae or clinically diagnosed chronic periodontitis were characterized by PCR-denaturing gradient gel electrophoresis (DGGE) with primers specific for the V2-V3 region of the eubacterial 16S rRNA gene. A hierarchical dendrogram was constructed from band patterns. All unique PCR amplicons (DGGE bands) were sequenced for identity. Samples were also analyzed for the presence of
Actinobacillus actinomycetemcomitans
,
Porphyromonas gingivalis
, and
Tannerella forsythensis
by multiplex PCR. Associations of patient age, gender, and smoking status together with the presence of each unique band and putative periodontal pathogens with disease were assessed by logistic regression. Periodontal pockets were colonized by complex eubacterial communities (10 to 40 distinct DGGE bands) with substantial individual variation in the community profile. Species diversity in health and disease was determined by the Shannon-Weaver index of diversity and compared by the Mann-Whitney U test. Sequence analyses of DGGE amplicons indicated the occurrence of many nontypical oral species and eubacteria previously associated with this environment. With the exception of
T. forsythensis
, the putative pathogens were not detected by DGGE. Multiplex PCR, however, detected
T. forsythensis
,
A. actinomycetemcomitans
, and
P. gingivalis
in 9% 16%, and 29% of the patients with disease, respectively. The presence of
A. actinomycetemcomitans
was significantly associated with disease (
P
< 0.01). Statistical analyses indicated that the presence of
Treponema socranskii
and
Pseudomonas
sp. was a significant predictor of disease (
P
< 0.05) and that there was no significant difference (
P
> 0.05) in terms of eubacterial species diversity between health and disease.
Peritoneal Lavage Cells of Indonesian Thin-Tail Sheep Mediate Antibody-Dependent Superoxide Radical Cytotoxicity In Vitro against Newly Excysted Juvenile
Fasciola gigantica
but Not Juvenile
Fasciola hepatica
Authors: Piedrafita David , Estuningsih Endah , Pleasance Jill , Prowse Rhoda , Raadsma Herman W. , Meeusen Els N. T. , Spithill Terry W. 
Published: January 2007

ABSTRACT

Indonesian thin-tail (ITT) sheep resist infection by
Fasciola gigantica
by an immunological mechanism within 2 to 4 weeks of infection yet are susceptible to
F. hepatica
infection. Studies of ITT sheep show that little liver damage occurs following
F. gigantica
infection, suggesting that the invading parasites are killed within the peritoneum or shortly after reaching the liver. We investigated whether cells isolated from the peritoneums of ITT sheep could kill newly excysted juvenile
F. gigantica
in vitro and act as a potential mechanism of resistance against
F. gigantica
infection. Peritoneal cells from
F. gigantica
-infected sheep, rich in macrophages and eosinophils, mediated antibody-dependent cytotoxicity against juvenile
F. gigantica
in vitro. Cytotoxicity was dependent on contact between the parasite and effector cells. Isolated mammary gland eosinophils of
F. gigantica
-infected sheep, or resident peritoneal monocytes/macrophages from uninfected sheep, also killed the juvenile parasites in vitro. By using inhibitors, we show that the molecular mechanism of killing in these assays was dependent on the production of superoxide radicals by macrophages and eosinophils. In contrast, this cytotoxic mechanism was ineffective against juvenile
F. hepatica
parasites in vitro. Analysis of superoxide dismutase activity and mRNA levels showed that activity and gene expression were higher in
F. hepatica
than in
F. gigantica
, suggesting a possible role for this enzyme in the resistance of
F. hepatica
to superoxide-mediated killing. We suggest that ovine macrophages and eosinophils, acting in concert with a specific antibody, may be important effector cells involved in the resistance of ITT sheep to
F. gigantica
.
Sprint training reduces urinary purine loss following intense exercise in humans
Authors: Stathis Christos G. , Carey Michael F. , Hayes Alan , Garnham Andrew P. , Snow Rodney J. 
Published: January 2007

The influence of sprint training on endogenous urinary purine loss was examined in 7 active male subjects (age, 23.1 ± 1.8 y; body mass, 76.1 ± 3.1 kg; VO2 peak, 56.3 ± 4.0 mL·kg–1·min–1). Each subject performed a 30 s sprint performance test (PT), before and after 7 d of sprint training. Training consisted of 15 sprints, each lasting 10 s, on an air-braked cycle ergometer performed twice each day. A rest period of 50 s separated each sprint during training. Sprint training resulted in a 20% higher muscle ATP immediately after PT, a lower IMP (57% and 89%, immediately after and 10 min after PT, respectively), and inosine accumulation (53% and 56%, immediately after and 10 min after the PT, respectively). Sprint training also attenuated the exercise-induced increases in plasma inosine, hypoxanthine (Hx), and uric acid during the first 120 min of recovery and reduced the total urinary excretion of purines (inosine + Hx + uric acid) in the 24 h recovery period following intense exercise. These results show that intermittent sprint training reduces the total urinary purine excretion after a 30 s sprint bout.
Combinations of Tomato and Broccoli Enhance Antitumor Activity in Dunning R3327-H Prostate Adenocarcinomas
Authors: Canene-Adams Kirstie , Lindshield Brian L. , Wang Shihua , Jeffery Elizabeth H. , Clinton Steven K. , Erdman John W. 
Published: January 2007

Abstract
The consumption of diets containing 5 to 10 servings of fruits and vegetables daily is the foundation of public health recommendations for cancer prevention, yet this concept has not been tested in experimental models of prostate cancer. We evaluated combinations of tomato and broccoli in the Dunning R3327-H prostate adenocarcinoma model. Male Copenhagen rats (n = 206) were fed diets containing 10% tomato, 10% broccoli, 5% tomato plus 5% broccoli (5:5 combination), 10% tomato plus 10% broccoli (10:10 combination) powders, or lycopene (23 or 224 nmol/g diet) for ∼22 weeks starting 1 month prior to receiving s.c. tumor implants. We compared the effects of diet to surgical castration (2 weeks before termination) or finasteride (5 mg/kg body weight orally, 6 d/wk). Castration reduced prostate weights, tumor areas, and tumor weight (62%, P &lt; 0.001), whereas finasteride reduced prostate weights (P &lt; 0.0001), but had no effect on tumor area or weight. Lycopene at 23 or 224 nmol/g of the diet insignificantly reduced tumor weights by 7% or 18%, respectively, whereas tomato reduced tumor weight by 34% (P &lt; 0.05). Broccoli decreased tumor weights by 42% (P &lt; 0.01) whereas the 10:10 combination caused a 52% decrease (P &lt; 0.001). Tumor growth reductions were associated with reduced proliferation and increased apoptosis, as quantified by proliferating cell nuclear antigen immunohistochemistry and the ApopTag assay. The combination of tomato and broccoli was more effective at slowing tumor growth than either tomato or broccoli alone and supports the public health recommendations to increase the intake of a variety of plant components. [Cancer Res 2007;67(2):836–43]
Do Global Models Properly Represent the Feedback between Land and Atmosphere?
Authors: Dirmeyer Paul A. , Koster Randal D. , Guo Zhichang 
Published: January 2007

Abstract
The Global Energy and Water Cycle Experiment/Climate Variability and Predictability (GEWEX/CLIVAR) Global Land–Atmosphere Coupling Experiment (GLACE) has provided an estimate of the global distribution of land–atmosphere coupling strength during boreal summer based on the results from a dozen weather and climate models. However, there is a great deal of variation among models, attributable to a range of sensitivities in the simulation of both the terrestrial and atmospheric branches of the hydrologic cycle. It remains an open question whether any of the models, or the multimodel estimate, reflects the actual pattern and strength of land–atmosphere coupling in the earth’s hydrologic cycle. The authors attempt to diagnose this by examining the local covariability of key atmospheric and land surface variables both in models and in those few locations where comparable, relatively complete, long-term measurements exist. Most models do not encompass well the observed relationships between surface and atmospheric state variables and fluxes, suggesting that these models do not represent land–atmosphere coupling correctly. Specifically, there is evidence that systematic biases in near-surface temperature and humidity among all models may contribute to incorrect surface flux sensitivities. However, the multimodel mean generally validates better than most or all of the individual models. Regional precipitation behavior (lagged autocorrelation and predisposition toward maintenance of extremes) between models and observations is also compared. Again a great deal of variation is found among the participating models, but remarkably accurate behavior of the multimodel mean.
Onset of Snowmelt and Streamflow in 2004 in the Western United States: How Shading May Affect Spring Streamflow Timing in a Warmer World
Authors: Lundquist Jessica D. , Flint Alan L. 
Published: January 2007

Abstract
Historic streamflow records show that the onset of snowfed streamflow in the western United States has shifted earlier over the past 50 yr, and March 2004 was one of the earliest onsets on record. Record high temperatures occurred throughout the western United States during the second week of March, and U.S. Geological Survey (USGS) stream gauges throughout the area recorded early onsets of streamflow at this time. However, a set of nested subbasins in Yosemite National Park, California, told a more complicated story. In spite of high air temperatures, many streams draining high-elevation basins did not start flowing until later in the spring. Temperatures during early March 2004 were as high as temperatures in late March 2002, when streams at all of the monitored Yosemite basins began flowing at the same time. However, the March 2004 onset occurred before the spring equinox, when the sun was lower in the sky. Thus, shading and solar radiation differences played a much more important role in 2004, leading to differences in streamflow timing. These results suggest that as temperatures warm and spring melt shifts earlier in the season, topographic effects will play an even more important role than at present in determining snowmelt timing.
Comparison of the Scaling Characteristics of Rainfall Derived from Space-Based and Ground-Based Radar Observations
Authors: Gebremichael Mekonnen , Over Thomas M. , Krajewski Witold F. 
Published: January 2007

Abstract
In view of the importance of tropical rainfall and the ubiquitous need for its estimates in climate modeling, the authors assess the ability of the Tropical Rainfall Measuring Mission (TRMM) precipitation radar (PR) to characterize the scaling characteristics of rainfall by comparing the derived results with those obtained from the ground-based radar (GR) data. The analysis is based on 59 months of PR and GR rain rates at three TRMM ground validation (GV) sites: Houston, Texas; Melbourne, Florida; and Kwajalein Atoll, Republic of the Marshall Islands. The authors consider spatial scales ranging from about 4 to 64 km at a fixed temporal scale corresponding to the sensor “instantaneous” snapshots (∼15 min). The focus is on the scaling of the marginal moments, which allows estimation of the scaling parameters from a single scene of data. The standard rainfall products of the PR and the GR are compared in terms of distributions of the scaling parameter estimates, the connection between the scaling parameters and the large-scale spatial average rain rate, and deviations from scale invariance. The five main results are as follows: 1) the PR yields values of the rain intermittence scaling parameter within 20% of the GR estimate; 2) both the PR and GR data show a one-to-one relationship between the intermittence scaling parameter and the large-scale spatial average rain rate that can be fit with the same functional form; 3) the PR underestimates the curvature of the scaling function from 20% to 50%, implying that high rain-rate extremes would be missed in a downscaling procedure; 4) the majority of the scenes (&gt;85%) from both the PR and GR are scale invariant at the moment orders q = 0 and 2; and 5) the scale-invariance property tends to break down more likely over ocean than over land; the rainfall regimes that are not scale invariant are dominated by light storms covering large areas. Our results further show that for a sampling size of one year of data, the TRMM temporal sampling does not significantly affect the derived scaling characteristics. The authors conclude that the TRMM PR has the ability to characterize the basic scaling properties of rainfall, though the resulting parameters are subject to some degree of uncertainty.
Assimilation of Disaggregated Microwave Soil Moisture into a Hydrologic Model Using Coarse-Scale Meteorological Data
Authors: Merlin O. , Chehbouni A. , Boulet G. , Kerr Y. 
Published: January 2007

AbstractNear-surface soil moisture retrieved from Soil Moisture and Ocean Salinity (SMOS)-type data is downscaled and assimilated into a distributed soil–vegetation–atmosphere transfer (SVAT) model with the ensemble Kalman filter. Because satellite-based meteorological data (notably rainfall) are not currently available at finescale, coarse-scale data are used as forcing in both the disaggregation and the assimilation. Synthetic coarse-scale observations are generated from the Monsoon ‘90 data by aggregating the Push Broom Microwave Radiometer (PBMR) pixels covering the eight meteorological and flux (METFLUX) stations and by averaging the meteorological measurements. The performance of the disaggregation/assimilation coupling scheme is then assessed in terms of surface soil moisture and latent heat flux predictions over the 19-day period of METFLUX measurements. It is found that the disaggregation improves the assimilation results, and vice versa, the assimilation of the disaggregated microwave soil moisture improves the spatial distribution of surface soil moisture at the observation time. These results are obtainable regardless of the spatial scale at which solar radiation, air temperature, wind speed, and air humidity are available within the microwave pixel and for an assimilation frequency varying from 1/1 day to 1/5 days.
Stress and depression in family carers following traumatic brain injury: the influence of beliefs about difficult behaviours
Authors: Riley Gerard A 
Published: January 2007

Objective: Difficult behaviours are significant contributors to the distress experienced by carers of people with a traumatic brain injury. This study investigated whether the beliefs carers hold about such behaviours also contribute to the distress. Design: Questionnaire survey. Participants: Forty family carers recruited from Headway, a traumatic brain injury support organization. Main measures: Zung's Self-Rating Depression Scale, Perceived Stress Scale, Social Support Questionnaire, a measure of the severity of difficult behaviours shown by the person cared for and two measures of carer beliefs about the behaviour (including the Controlling Beliefs Scale). Results: Higher depression and stress scores were associated with more severe behaviours and less social support. Carer belief in their own ability to control the behaviours was associated with less stress. Belief that the behaviour was under the control of the person with traumatic brain injury and/or was motivated by hostile intentions was associated with more depression but less stress. Taken together, severity of behaviour and social support accounted for about 19% of the variance in both depression and stress scores. Carer beliefs accounted for another 5% of the depression scores, and another 11% of the stress scores. Conclusions: The results were consistent with the idea that carer beliefs about difficult behaviour contribute to carer distress, but longitudinal and treatment studies are needed to establish causality.
Development of the Adelaide Driving Self-Efficacy Scale
Authors: George Stacey , Clark Michael , Crotty Maria 
Published: January 2007

Objective: To describe the development of the Adelaide Driving Self-Efficacy Scale (ADSES) and to report on its reliability and validity. Methods: A set of 12 driving behaviours, developed through literature review, clinical experience and expert review, were rated for self-efficacy using a Likert scale. Internal consistency was investigated using a Cronbach's alpha coefficient and construct validity by comparing ADSES scores of stroke and non-stroke drivers. Criterion-related validity was examined by comparing ADSES scores with the result on a standardized on-road assessment. Setting: A rehabilitation hospital in Adelaide, South Australia. Participants: Staff from the hospital and stroke patients from the rehabilitation unit. Data from a non-stroke sample (n -/ 79) and stroke patients (n -/ 81) were used to test internal consistency and construct validity. A separate group of 45 people recommended for a driving assessment, of whom 34 were stroke patients, were used to test criterion validity. Results: Cronbach's alpha coefficient was 0.98, indicating high internal consistency. The non-stroke and stroke groups showed significant differences in ADSES scores (t(158)-/ 5.5, P B < 0.05), demonstrating construct validity. Differences in ADSES scores for those participants who passed or failed the on-road assessment were significant for both the entire driving assessment group (t(43)-/ 3.2, P B < 0.05) and the stroke subgroup (t(43)-/ 3.2, P B < 0.05), indicating criterion validity. Conclusion: The ADSES has demonstrated internal consistency and construct validity with the stroke and non-stroke population. The scale demonstrated criterion validity in its relationship with outcome of an on-road driving assessment. It appears to be a reliable and valid measure of driving self-efficacy.
Tobacco use among students aged 13–15 years in Greece: the GYTS project
Authors: Kyrlesi Athina , Soteriades Elpidoforos S , Warren Charles W , Kremastinou Jeni , Papastergiou Panagiotis , Jones Nathan R , Hadjichristodoulou Christos 
Published: January 2007

Abstract

Background
Data on the prevalence of tobacco use among teenagers in Greece are limited. We examined the prevalence of smoking among middle-school students in Greece using the Global Youth Tobacco Survey (GYTS).

Methods
The Global Youth Tobacco Survey was implemented in Greece during the academic year 2004 – 2005 by the University of Thessaly and the National School of Public Health. Data were collected using the GYTS self-administered anonymous questionnaire, which was distributed by specifically trained field workers to a nationally representative sample of middle-school students aged 13–15 years (through randomly selected schools and classes), randomly selected through a two-stage cluster sample design. Data processing and statistical analyses were performed at the Centers for Disease Control and Prevention (CDC).

Results
About one third of the students 32.1% (29.4 – 35.0) reported that they had tried tobacco in the past, while 16.2% (14.3 – 18.4) reported being current users of tobacco products. In addition, 1 in 4 of ever smokers reported that they began smoking before the age of 10 years old. Almost 1 in 5 never smokers reported being susceptible to initiate smoking in the next year and about 89.8% (88.3 – 91.1) of the respondents were exposed to environmental tobacco smoke in their homes and 94.1% (93.2 – 94.9) in public places. Finally, a strikingly high number of students 95% (89.5 – 97.7) reported that they were able to buy their own cigarettes without restrictions.

Conclusion
The results of the GYTS show that the prevalence of smoking in middle-school children is alarmingly high in Greece. Smoking among young people constitutes a significant problem that is destined to worsen in the absence of any comprehensive efforts focused on strict anti-smoking legislation, policies and tobacco control interventions targeting children at a young age.