bluuebunny/crossref_metadata_2025_split huggingface dataset:
High Proportion of False-Positive Clostridium difficile Enzyme Immunoassays for Toxin A and B in Pediatric Patients
Authors: Toltzis Philip , Nerandzic Michelle M. , Saade Elie , O'Riordan Mary Ann , Smathers Sarah , Zaoutis Theoklis , Kim Jason , Donskey Curtis J. 
Published: January 2012

Objectives.To determine the frequency of false-positive Clostridium difficile toxin enzyme immunoassay (EIA) results in hospitalized children and to examine potential reasons for this false positivity.Design.Nested case-control.Setting.Two tertiary care pediatric hospitals.Methods.As part of a natural history study, prospectively collected EIA-positive stools were cultured for toxigenic C. difficile, and characteristics of children with false-positive and true-positive EIA results were compared. EIA-positive/culture-negative samples were recultured after dilution and enrichment steps, were evaluated for presence of the tcdB gene by polymerase chain reaction (PCR), and were further cultured for Clostridium sordellii, a cause of false-positive EIA toxin assays.Results.Of 112 EIA-positive stools cultured, 72 grew toxigenic C. difficile and 40 did not, indicating a positive predictive value of 64% in this population. The estimated prevalence of C. difficile infection (CDI) in the study sites among children tested for this pathogen was 5%–7%. Children with false-positive EIA results were significantly younger than those with true-positive tests but did not differ in other characteristics. No false-positive specimens yielded C. difficile when cultured after enrichment or serial dilution, 1 specimen was positive for tcdB by PCR, and none grew C. sordellii.Conclusions.Approximately one-third of EIA tests used to evaluate pediatric inpatients for CDI were falsely positive. This finding was likely due to the low prevalence of CDI in pediatric hospitals, which diminishes the test's positive predictive value. These data raise concerns about the use of EIA assays to diagnosis CDI in children.Infect Control Hosp Epidemiol 2012;33(2):175-179
Initiation and channelling of a microwave discharge by a plasma filament created in atmospheric air by an intense femtosecond laser pulse
Authors: Bodrov S B , Kulagin D I , Malkov Yu A , Murzanev A A , Smirnov A I , Stepanov A N 
Published: January 2012

Abstract
We study the initiation of a pulsed microwave discharge in atmospheric air by a plasma channel induced by intense femtosecond laser pulses. It is shown that the electric field threshold for the initiated discharge is lowered compared with the self-discharge by about a factor of two, from 25 to 12 kV cm−1. Channelling of the atmospheric-pressure microwave discharge in the direction of the plasma filament has been detected. The time of existence of the initiated discharge plasma was determined by the duration of the microwave pulse and amounted to 1–2 µs for the maximum electron density estimated as about 4 × 1015 cm−3. The developed theory of propagation of the microwave radiation along the plasma channel created by a femtosecond laser pulse predicts that the relatively low conductivity of the plasma and its rapid decay limit the characteristic scale of decay of the microwave fields confined by the plasma channel to a few centimetres.
The role of the seasonal and semi-diurnal tidal cycle on mesozooplankton variability in a shallow mixed estuary (Bahía Blanca, Argentina)
Authors: Menéndez M. Clara , Dutto M. Sofía , Piccolo M. Cintia , Hoffmeyer Mónica S. 
Published: January 2012

AbstractMenéndez, M. C., Dutto, M. S., Piccolo, M. C., and Hoffmeyer, M. S. 2012. The role of the seasonal and semi-diurnal tidal cycle on mesozooplankton variability in a shallow mixed estuary (Bahía Blanca, Argentina). – ICES Journal of Marine Science, 69: 389–398. The role of the seasonal and semi-diurnal tidal cycle on mesozooplankton dynamics was investigated in the inner zone of the Bahía Blanca Estuary (BBE), Argentina. Hydrological data and mesozooplankton samples were obtained bimonthly from December 2004 to April 2006, during 14 h tidal cycles. The mesozooplankton community was represented by 33 taxa. Taxa richness was greater near the bottom, where the contribution of benthic forms was notable. Abundances were greatest during summer (>5500 ind. m−3) and lowest during winter (<70 ind. m−3). The mesozooplankton community was dominated by Acartia tonsa and Eurytemora americana. Multivariate analyses revealed significant seasonal differences in community structure, especially in terms of density. Seasonal differences in community structure are well explained by the natural change of abiotic and biotic conditions, but temperature played a key role in structuring the mesozooplankton community. The zooplankton was significantly more abundant during the ebb, suggesting that local hydrological conditions are responsible for the spatial variations. The results demonstrate how variable the mesozooplankton community structure can be over different time-scales and provide a better understanding of zooplankton variability in the BBE and other temperate, turbid, mixed systems.
Distinct Gut Microbiota in Southeastern African and Northern European Infants
Authors: Grześkowiak Łukasz , Collado Maria Carmen , Mangani Charles , Maleta Kenneth , Laitinen Kirsi , Ashorn Per , Isolauri Erika , Salminen Seppo 
Published: January 2012

ABSTRACTBackground and Objective:The intestinal microbiota composition in infants reflects the early environment. Our objective was to compare the gut microbiota in 6‐month‐old infants living in rural Malawi with children of the same age living in urban Finland, both being breast‐fed and having an age‐appropriate diet typical for each area.Methods:Malawian 6‐month‐old infants (n = 44) were compared with Finnish infants (n = 31) of the same age. In both cohorts, infant stool samples were available for microbiota characterization by flow cytometry‐fluorescent in situ hybridization and quantitative polymerase chain reaction methods.Results:Bifidobacteria were dominant at 6 months of age in all of the infants, although in greater proportions in Malawian (70.8%) than in Finnish infants (46.8%; P < 0.001). Additional distinctions in bacterial group composition comprised Bacteroides‐Prevotella (17.2% vs 4.7%; P < 0.001) and Clostridium histolyticum (4.4% vs 2.8%; P = 0.01), respectively. The species Bifidobacterium adolescentis, Clostridium perfringens, and Staphylococcus aureus were absent in Malawian but detected in Finnish infants.Conclusions:The gut microbiota of 6‐month‐old infants in a low‐income country differs significantly from that in a high‐income country. This may have an effect on both the energy harvest from the diet typifying malnutrition and diarrheal diseases in low‐income countries and Western lifestyle diseases in high‐income countries.
Untargeted Metabolic Quantitative Trait Loci Analyses Reveal a Relationship between Primary Metabolism and Potato Tuber Quality
Authors: Carreno-Quintero Natalia , Acharjee Animesh , Maliepaard Chris , Bachem Christian W.B. , Mumm Roland , Bouwmeester Harro , Visser Richard G.F. , Keurentjes Joost J.B. 
Published: January 2012

Abstract
Recent advances in -omics technologies such as transcriptomics, metabolomics, and proteomics along with genotypic profiling have permitted dissection of the genetics of complex traits represented by molecular phenotypes in nonmodel species. To identify the genetic factors underlying variation in primary metabolism in potato (Solanum tuberosum), we have profiled primary metabolite content in a diploid potato mapping population, derived from crosses between S. tuberosum and wild relatives, using gas chromatography-time of flight-mass spectrometry. In total, 139 polar metabolites were detected, of which we identified metabolite quantitative trait loci for approximately 72% of the detected compounds. In order to obtain an insight into the relationships between metabolic traits and classical phenotypic traits, we also analyzed statistical associations between them. The combined analysis of genetic information through quantitative trait locus coincidence and the application of statistical learning methods provide information on putative indicators associated with the alterations in metabolic networks that affect complex phenotypic traits.
Low prevalence of Helicobacter pylori infection among patients with inflammatory bowel disease
Authors: Sonnenberg A. , Genta R. M. 
Published: January 2012

SummaryBackgroundThere is some preliminary evidence to suggest that patients with inflammatory bowel disease (IBD) are less frequently infected with Helicobacter pylori than the general population.AimTo examine whether the prevalence of Helicobacter pylori (H. pylori) is lower among IBD patients compared with non‐IBD individuals based on results from surgical pathology.MethodsFrom a database of surgical pathology reports, we recruited a sample of unique patients who underwent a same‐day bidirectional gastrointestinal endoscopy with biopsies. Of the total 65 515 patients, 1061 served as cases with IBD and 64 451 as controls without IBD. The histological presence of H. pylori was correlated with the patients’ demographic characteristics and histological presence of any oesophageal disease, Crohn's disease (CD), ulcerative colitis (UC) and indeterminate colitis (IND). Results were expressed as odds ratios (OR), using multivariate logistic regression to adjust for the cofounding influence of comorbidities and demographic characteristics.ResultsThe presence of H. pylori was inversely associated with IBD, the adjusted OR and their 95% confidence intervals being 0.48 (0.27–0.79) for CD, 0.59 (0.39–0.84) for UC and 0.43 (0.15–0.95) for IND. In contradistinction, H. pylori – negative gastritis was positively associated with IBD, the adjusted OR being 11.06 (7.98–15.02) for CD, 2.25 (1.31–3.60) for UC and 6.91 (3.50–12.30) for IND.ConclusionsOur study confirms an inverse association between H. pylori and IBD and a positive association between the H. pylori – negative gastritis and IBD. These relationships may open new avenues to study the pathogenesis of IBD.
Agricultural encroachment: implications for carbon sequestration in tropical African wetlands
Authors: Saunders Matthew J. , Kansiime Frank , Jones Michael B. 
Published: January 2012

AbstractTropical wetlands have been shown to exhibit high rates of net primary productivity and may therefore play an important role in global climate change mitigation through carbon assimilation and sequestration. Many permanently flooded areas of tropical East Africa are dominated by the highly productive C4 emergent macrophyte sedge, Cyperus papyrus L. (papyrus). However, increasing population densities around wetland margins in East Africa are reducing the extent of papyrus coverage due to the planting of subsistence crops such as Colocasia esculenta (cocoyam). In this paper, we assess the impact of this land use change on the carbon cycle and in particular the impacts of land conversion on net ecosystem carbon dioxide exchange. Eddy covariance techniques were used, on a campaign basis, to measure fluxes of carbon dioxide over both papyrus and cocoyam dominated wetlands located on the Ugandan shore of Lake Victoria. Peak rates of net photosynthetic CO2 assimilation, derived from monthly diurnal averages of net ecosystem exchange, of 28–35 μmol CO2 m−2 s−1 and 15–20 μmol CO2 m−2 s−1 were recorded in the papyrus and cocoyam wetlands, respectively, whereas night‐time respiratory losses ranged between 10 and 15 μmol CO2 m−2 s−1 at the papyrus wetland and 5–10 μmol CO2 m−2 s−1 at the cocoyam site. The integration of the flux data suggests that papyrus wetlands have the potential to act as a sink for significant amounts of carbon, in the region of 10 t C ha−1 yr−1. The cocoyam vegetation assimilated ~7 t C ha−1 yr−1 but when carbon exports from crop biomass removal were accounted for these wetlands represent a significant net loss of carbon of similar magnitude. The development of sustainable wetland management strategies are therefore required to promote the dual wetland function of crop production and the mitigation of greenhouse gas emissions especially under future climate change scenarios.
Deregulation of the CXCL12/CXCR4 axis in methotrexate chemotherapy–induced damage and recovery of the bone marrow microenvironment
Authors: Georgiou Kristen R. , Scherer Michaela A. , King Tristan J. , Foster Bruce K. , Xian Cory J. 
Published: January 2012

SummaryCancer chemotherapy disrupts the bone marrow (BM) microenvironment affecting steady‐state proliferation, differentiation and maintenance of haematopoietic (HSC) and stromal stem and progenitor cells; yet the underlying mechanisms and recovery potential of chemotherapy‐induced myelosuppression and bone loss remain unclear. While the CXCL12/CXCR4 chemotactic axis has been demonstrated to be critical in maintaining interactions between cells of the two lineages and progenitor cell homing to regions of need upon injury, whether it is involved in chemotherapy‐induced BM damage and repair is not clear. Here, a rat model of chemotherapy treatment with the commonly used antimetabolite methotrexate (MTX) (five once‐daily injections at 0.75 mg/kg/day) was used to investigate potential roles of CXCL12/CXCR4 axis in damage and recovery of the BM cell pool. Methotrexate treatment reduced marrow cellularity, which was accompanied by altered CXCL12 protein levels (increased in blood plasma but decreased in BM) and reduced CXCR4 mRNA expression in BM HSC cells. Accompanying the lower marrow CXCL12 protein levels (despite its increased mRNA expression in stromal cells) was increased gene and protein levels of metalloproteinase MMP‐9 in bone and BM. Furthermore, recombinant MMP‐9 was able to degrade CXCL12 in vitro. These findings suggest that MTX chemotherapy transiently alters BM cellularity and composition and that the reduced cellularity may be associated with increased MMP‐9 expression and deregulated CXCL12/CXCR4 chemotactic signalling.
Epigenetic regulation of the nitrosative stress response and intracellular macrophage survival by extraintestinal pathogenic Escherichia coli
Authors: Bateman Stacey L. , Seed Patrick C. 
Published: January 2012

SummaryExtraintestinal pathogenic Escherichia coli (ExPEC) reside in the enteric tract as a commensal reservoir, but can transition to a pathogenic state by invading normally sterile niches, establishing infection and disseminating to invasive sites like the bloodstream. Macrophages are required for ExPEC dissemination, suggesting the pathogen has developed mechanisms to persist within professional phagocytes. Here, we report that FimX, an ExPEC‐associated DNA invertase that regulates the major virulence factor type 1 pili (T1P), is also an epigenetic regulator of a LuxR‐like response regulator HyxR. FimX regulated hyxR expression through bidirectional phase inversion of its promoter region at sites different from the type 1 pili promoter and independent of integration host factor (IHF). In vitro, transition from high to low HyxR expression produced enhanced tolerance of reactive nitrogen intermediates (RNIs), primarily through de‐repression of hmpA, encoding a nitric oxide‐detoxifying flavohaemoglobin. However, in the macrophage, HyxR produced large effects on intracellular survival in the presence and absence of RNI and independent of Hmp. Collectively, we have shown that the ability of ExPEC to survive in macrophages is contingent upon the proper transition from high to low HyxR expression through epigenetic regulatory control by FimX.
Development of Purkinje Cells in the Ovine Brain
Authors: Salouci M. , Engelen V. , Gyan M. , Antoine N. , Jacqmot O. , Mignon Y. , Kirschvink N. , Gabriel A. 
Published: January 2012

SummaryPurkinje cells are involved in many vital functions within the body. Twenty ovine fetuses ranging from 2 to 5 months of gestation, two lambs in the first week after birth and three adult sheep were studied. Sections of the cerebellum were stained with haematoxylin and eosin, cresyl violet and Klüver–Barrera. This study indicates that Purkinje cells began to appear after the 15th week of gestation. There were varying degrees of development of Purkinje cells in different zones of the cerebellum. Our findings in sheep fetuses suggest that the maturation of Purkinje cells starts in the caudal regions of the cerebellum and that the process begins in the vermis before it does in the cerebellar hemispheres. The alignment of Purkinje cells was found to be very regular in the caudal regions of the cerebellum. A partial absence of Purkinje cells in the rostral regions of the cerebellum was observed in both sheep fetuses and adult sheep. In the first post‐natal week, some ectopic Purkinje cells were found in the white matter of the cerebellum.
Do Feeding Resources Induce the Adoption of Resource Defence Polygyny in a Lekking Butterfly?
Authors: Peixoto Paulo E. C. , Muniz Danilo , Benson Woodruff W. 
Published: January 2012

AbstractAmong polygynous species, males often compete for the possession of mating sites to increase their reproductive success. Weaker individuals frequently adopt alternative non‐territorial mate‐locating tactics, but the adoption of alternative territorial tactics may also occur. Although alternative tactics with territory defence are less common in arthropods, factors that drive its adoption may provide information to understand the organization of different territorial mating systems in the group. Here we investigate the adoption of resource‐based territoriality as an alternative to a non‐resource‐based one by males of the butterfly Paryphthimoides phronius. Male P. phronius commonly defend sunny clearings lacking feeding resources in the forest edge (non‐resource‐based territoriality). However, after experimentally offering fermenting fruit in previously undefended sites, we showed that males also adopt a resource defence tactic. Males in territories with fermenting fruits apparently feed on this resource when they are not defending the territory. However, males in sites without resources did not migrate to territories with resources when given the opportunity. To our knowledge, this is the first experimental investigation to show a non‐resource‐ and an alternative resource‐based mate‐locating tactic in a butterfly. We suggest that this behavioural flexibility may represent an important step to understand the ecological factors responsible for the organization and evolution of different territorial mating systems in insects.
Susceptibility to Phytophthora cinnamomi of the commonest morphotypes of Holm oak in southern Spain
Authors: Serrano M. S. , De Vita P. , Carbonero M. D. , Fernández F. , Fernández‐Rebollo P. , Sánchez M. E. 
Published: January 2012

SummaryThe four main morphotypes of Holm oak (Quercus ilex subsp. ballota) present in Andalusia (expansa, macrocarpa, microcarpa and rotundifolia) were infected with Phytophthora cinnamomi to determine their susceptibility to the root pathogen. No large differences were found among the four morphotypes in the infection of roots, which always showed a high degree of necrosis. However, the different responses of the foliage to infection separated the four morphotypes of Holm oak into three groups: very susceptible (microcarpa), susceptible (expansa) and moderately susceptible (rotundifolia and macrocarpa). The natural hybrid Q. ilex ballota–Q. faginea exhibited a low level of root and foliar symptoms when infected with P. cinnamomi. Quercus faginea could be considered as a source of resistance to P. cinnamomi in future breeding programmes.
The rapid onset of multiple squamous cell carcinomas in two patients commenced on ustekinumab as treatment of psoriasis
Authors: Young Lauren , Czarnecki D 
Published: January 2012

ABSTRACTWe report the cases of two patients who developed eruptive cutaneous squamous cell carcinomas (SCC) soon after commencement of ustekinumab, as treatment of moderate to severe plaque type psoriasis. Ustekinumab is a human monoclonal antibody with a novel mechanism, selectively targeting the shared p40 subunit of interleukin‐12 (IL‐12) and IL‐23. Its efficacy has been well documented in three large phase‐III trials (PHOENIX I, PHEONIX 2, ACCEPT). Safety data on this new biological agent continue to grow. To date, no link between ustekinumab and cutaneous carcinogenesis has been demonstrated and, to our knowledge, these cases are the first of their kind. Importantly, both these patients had independent risk factors for developing non‐melanoma skin cancers; however, the specific time correlation with the administration of ustekinumab is of note. Our report suggests that ustekinumab may allow the development of cutaneous carcinomata in predisposed individuals.
Epiphyte grazing enhances productivity of remnant seagrass patches
Authors: VERHOEVEN MIRELLA P. C. , KELAHER BRENDAN P. , BISHOP MELANIE J. , RALPH PETER J. 
Published: January 2012

AbstractAnthropogenic nutrient enrichment is increasingly modifying community structure and ecosystem functioning in terrestrial and aquatic ecosystems. In marine ecosystems, the paradigm is that nutrient enrichment leads to a decline of seagrasses by stimulating epiphytic algal growth, which shades and overgrows seagrasses. This ignores the potential for herbivores, which graze upon epiphytic algae, to partially or wholly counter such nutrient effects. We conducted a field experiment to assess the role that the trochid gastropod Calthalotia fragum plays in reducing nutrient impacts on the seagrass, Posidonia australis, in an urbanized Australian estuary, Botany Bay, Sydney. In a field experiment, where nutrient loading and grazer density were orthogonally manipulated, nutrient enrichment failed to promote epiphyte biomass or diminish growth and primary productivity of P. australis. To the contrary, nutrient enrichment enhanced photosynthesis of the seagrass in plots where the grazer was present at higher density. Epiphytic growth was negatively affected by increased C. fragum density, while P. australis shoot growth was positively influenced. Thus, in this study system, grazing appears to play a much greater role in determining seagrass primary productivity and above‐ground growth than moderate nutrient loading, suggesting that the interaction between grazers and nutrients depends on the relative levels of each. Our study contributes to a growing body of literature suggesting that effects of nutrient loading on benthic assemblages are not universally negative, but are dependent on the biotic and abiotic setting.