bluuebunny/crossref_metadata_2025_split huggingface dataset:
Low Levels of β-Lactam Antibiotics Induce Extracellular DNA Release and Biofilm Formation in Staphylococcus aureus
Authors: Kaplan Jeffrey B. , Izano Era A. , Gopal Prerna , Karwacki Michael T. , Kim Sangho , Bose Jeffrey L. , Bayles Kenneth W. , Horswill Alexander R. 
Published: August 2012

ABSTRACT

Subminimal inhibitory concentrations of antibiotics have been shown to induce bacterial biofilm formation. Few studies have investigated antibiotic-induced biofilm formation in
Staphylococcus aureus
, an important human pathogen. Our goal was to measure
S. aureus
biofilm formation in the presence of low levels of β-lactam antibiotics. Fifteen phylogenetically diverse methicillin-resistant
Staphylococcus aureus
(MRSA) and methicillin-sensitive
S. aureus
(MSSA) strains were employed. Methicillin, ampicillin, amoxicillin, and cloxacillin were added to cultures at concentrations ranging from 0× to 1× MIC. Biofilm formation was measured in 96-well microtiter plates using a crystal violet binding assay. Autoaggregation was measured using a visual test tube settling assay. Extracellular DNA was quantitated using agarose gel electrophoresis. All four antibiotics induced biofilm formation in some strains. The amount of biofilm induction was as high as 10-fold and was inversely proportional to the amount of biofilm produced by the strain in the absence of antibiotics. MRSA strains of lineages USA300, USA400, and USA500 exhibited the highest levels of methicillin-induced biofilm induction. Biofilm formation induced by low-level methicillin was inhibited by DNase. Low-level methicillin also induced DNase-sensitive autoaggregation and extracellular DNA release. The biofilm induction phenotype was absent in a strain deficient in autolysin (
atl
). Our findings demonstrate that subminimal inhibitory concentrations of β-lactam antibiotics significantly induce autolysin-dependent extracellular DNA release and biofilm formation in some strains of
S. aureus
.

IMPORTANCE
The widespread use of antibiotics as growth promoters in agriculture may expose bacteria to low levels of the drugs. The aim of this study was to investigate the effects of low levels of antibiotics on bacterial autoaggregation and biofilm formation, two processes that have been shown to foster genetic exchange and antibiotic resistance. We found that low levels of β-lactam antibiotics, a class commonly used in both clinical and agricultural settings, caused significant autoaggregation and biofilm formation by the important human pathogen
Staphylococcus aureus
. Both processes were dependent on cell lysis and release of DNA into the environment. The effect was most pronounced among multidrug-resistant strains known as methicillin-resistant
S. aureus
(MRSA). These results may shed light on the recalcitrance of some bacterial infections to antibiotic treatment in clinical settings and the evolution of antibiotic-resistant bacteria in agricultural settings.
Influenza Virus Resistance to Human Neutralizing Antibodies
Authors: Crowe James E. 
Published: August 2012

ABSTRACT
The human antibody repertoire has an exceptionally large capacity to recognize new or changing antigens through combinatorial and junctional diversity established at the time of V(D)J recombination and through somatic hypermutation. Influenza viruses exhibit a relentless capacity to escape the human antibody response by altering the amino acids of their surface proteins in hypervariable domains that exhibit a high level of structural plasticity. Both parties in this high-stakes game of shape shifting drive structural evolution of their functional proteins (the B cell receptor/antibody on one side and the viral hemagglutinin and neuraminidase proteins on the other) using error-prone polymerase systems. It is likely that most of the genetic mutations that occur in these systems are deleterious, resulting in the failure of the B cell or virus with mutations to propagate in the immune repertoire or viral quasispecies. A subset of mutations is tolerated in functional surface proteins that enter the B cell or virus progeny pool. In both cases, selection occurs in the population of mutated and unmutated species. In cases where the functional avidity of the B cell receptor is increased significantly, that clone may be selected for preferential expansion. In contrast, an influenza virus that “escapes” the inhibitory effect of secreted antibodies may represent a high proportion of the progeny virus in that host. The recent paper by O’Donnell et al. [C. D. O’Donnell et al., mBio 3(3):e00120-12, 2012] identifies a mechanism for antibody resistance that does not require escape from binding but rather achieves a greater efficiency in replication.
Species, live status, and diameter are important tree features for diversity and abundance of tree microhabitats in subnatural montane beech–fir forests1This article is one of a selection of papers from the International Symposium on Dynamics and Ecological Services of Deadwood in Forest Ecosystems.
Authors: Larrieu Laurent , Cabanettes Alain 
Published: August 2012

Because quantitative data on the distribution of whole microhabitat sets are still lacking to indirectly assess taxonomic biodiversity in forests, we studied the distribution of seven key microhabitat types in 10 montane European beech ( Fagus sylvatica L.) – silver fir ( Abies alba Mill.) forests (Pyrénées, France) that had not been harvested for several decades. We examined 2105 live trees and 526 snags. Frequencies of cavities and dendrothelms were significantly higher on live beech than on fir. Sap runs were strictly found on live fir. Frequencies of cracks and saproxylic fungi were significantly higher on snags than on live trees. Seventy percent of live beeches but only 18% of firs carried one or more microhabitats. For both beech and fir and for each microhabitat type, we found, using the recursive partitioning method, one to three diameter thresholds that each corresponded to a significant change in the probability of microhabitat presence. When considering the whole microhabitat set, the most significant diameter thresholds were 42, 60, 73, and 89 cm for beech and 99 cm for fir. We suggest that forest managers conserve (i) mixed stands and (ii) beech with a diameter at breast height >90 cm and fir >100 cm. These rules should be adapted for each forest ecosystem.
Phenology and duration of remigial moult in Surf Scoters (Melanitta perspicillata) and White-winged Scoters (Melanitta fusca) on the Pacific coast of North America
Authors: Dickson R.D. , Esler D. , Hupp J.W. , Anderson E.M. , Evenson J.R. , Barrett J. 
Published: August 2012

By quantifying phenology and duration of remigial moult in Surf Scoters ( Melanitta perspicillata (L., 1758)) and White-winged Scoters ( Melanitta fusca (L., 1758)), we tested whether timing of moult is dictated by temporal optima or constraints. Scoters (n = 3481) were captured during moult in Alaska, British Columbia, and Washington, and remigial emergence dates were determined. We provide evidence for a pre-emergence interval of 7.3 days that occurs after old primaries are shed and before new ones become visible. All age and sex classes of both scoter species exhibited a wide range of emergence dates (Surf Scoters: 26 June to 22 September; White-winged Scoters: 6 July to 21 September) suggestive of a lack of strong temporal optima for remigial moult. For both species, timing of moult was influenced by site, year, age, and sex. Relative to other waterfowl species, scoters have typical remigial growth rates (Surf Scoters: 3.9 mm·day–1; White-winged Scoters: 4.3 mm·day–1) but a long flightless period (34–49 days), in part because their relatively high wing-loading requires a greater proportion of feather regrowth to regain flight. Our data suggest that moulting scoters are not under strong selective pressure to complete moult quickly.
Sex and strain differences in isotope turnover rates and metabolism in house mice (Mus musculus)
Authors: MacAvoy S.E. , Lazaroff S. , Kraeer K. , Arneson L.S. 
Published: August 2012

The rate of nutrient incorporation into most organisms is an unknown but important factor in temporally variable systems. We investigate within-species variation in tissue turnover and metabolic rate among house mice ( Mus musculus L., 1758). By establishing a predictive relationship between tissue turnover rate and metabolic rate, field-based studies could more easily estimate tissue turnover rates using metabolic rate as a surrogate. Here, a diet change was administered using male and female mice of two strains (BALB/c and CBA/J) to test whether a predictive relationship was detectable within a species. Resting metabolic rate (mean values of 1.50–3.64 mL O2·h–1·g–1) and metabolic tissue turnover m (0.02–0.07), were significantly different between sexes, but not between strains. Females of both strains exhibited a nitrogen turnover rate significantly faster than males. Females had less mass than males, which could account for the differences in tissue replacement rates between sexes. The difference in metabolic rate within a species (between strains) may not be large enough to affect the rate of tissue turnover, suggesting that field researchers may be able to assume similar turnover rates among same-sex individuals of the same species. However, it may be important to account for sexual dimorphism when studying tissue turnover and metabolism.
Gastrointestinal parasites of coyotes (Canis latrans) in the metropolitan area of Calgary, Alberta, Canada
Authors: Liccioli S. , Catalano S. , Kutz S.J. , Lejeune M. , Verocai G.G. , Duignan P.J. , Fuentealba C. , Hart M. , Ruckstuhl K.E. , Massolo A. 
Published: August 2012

Disease ecology is a relevant but relatively unexplored subject of research in urban coyotes ( Canis latrans Say, 1823). In fact, this carnivore may play a role in the circulation of parasites that can have implications on the health of humans and domestic dogs, but can also be affected by pathogens transmitted from domestic reservoirs. To investigate the gastrointestinal parasites of urban coyotes in Calgary, Alberta, Canada, we analyzed 61 carcasses and 247 fecal samples collected within the metropolitan area, including city parks, in 2009–2010. We found nine parasite taxa: Toxascaris leonina (Linstow, 1902), Uncinaria stenocephala (Railliet, 1884), Ancylostoma caninum (Ercolani, 1859), Pterygodermatites affinis (Jägerskiöld, 1904), Trichuris vulpis (Froelich, 1789), Echinococcus multilocularis Leuckart, 1863, Taenia crassiceps (Zeder, 1800), genus Giardia Kunstler, 1882, and genus Cystoisospora Frenkel, 1977. Factors related to coyote ecology, habitat characteristics, and dog management likely influence the community of coyote parasites in an urban environment, and need to be taken into account to assess the actual role of this carnivore in the maintenance of parasites in the city landscape. Further research is needed to assess the current risk for transmission of potentially zoonotic parasites (e.g., E. multilocularis, T. crassiceps, Giardia sp.) among coyotes, dogs, and humans.
Creativity-Supporting Learning Environment---CSLE
Authors: Apiola Mikko , Lattu Matti , Pasanen Tomi A. 
Published: August 2012

Despite much public discussion about the importance of creativity and innovation-friendly teaching in Finnish higher education, the impact of the general opinion on actual teaching practices has been limited. In the Finnish computer science education the teaching mostly follows a pattern of lectures, fixed exercise sets, and exams. With this article we want to open a discussion about possibilities of enhancing the learning environment by focusing on creative problem solving. We will present results from two research experiments in which we aimed to provide computer science students with a practically oriented learning environment with an explicit intention of supporting the creative work of students. There exists a vast amount of scientific theory about creativity, yet it is unclear on how to turn that theory into practice. Thus, our main interest was to find ways of applying creativity theory in practice in the context of computer science education.
Our research experiments consist of a practically oriented computer science course, where LEGO®Mindstorms robots were used as the platform for the student work. Methodological tools used in this study included content analysis of student products, observations from our learning sessions and semi-structured interviews with the students. The course was organised two times: the first time was in spring 2009 and the second in spring 2010. The total number of attending students was 72.
In this article we argue that our approach of providing a creativity-supporting practical computer science course was a success. We gained a lot of ideas on how to support creativity, the students were clearly motivated, and they began to learn a new kind of experimental working style. The robotics kit seemed to work well both as a trigger for motivation and as a platform to support experimental learning, enhancing students’ creativity and working style.
In our opinion these findings are of great importance, and give promising practical ideas for the support of creativity in higher computer science education.
Reciprocal Metabolic Reprogramming through Lactate Shuttle Coordinately Influences Tumor-Stroma Interplay
Authors: Fiaschi Tania , Marini Alberto , Giannoni Elisa , Taddei Maria Letizia , Gandellini Paolo , De Donatis Alina , Lanciotti Michele , Serni Sergio , Cirri Paolo , Chiarugi Paola 
Published: August 2012

Abstract
Cancer-associated fibroblasts (CAF) engage in tumor progression by promoting the ability of cancer cells to undergo epithelial–mesenchymal transition (EMT), and also by enhancing stem cells traits and metastatic dissemination. Here we show that the reciprocal interplay between CAFs and prostate cancer cells goes beyond the engagement of EMT to include mutual metabolic reprogramming. Gene expression analysis of CAFs cultured ex vivo or human prostate fibroblasts obtained from benign prostate hyperplasia revealed that CAFs undergo Warburg metabolism and mitochondrial oxidative stress. This metabolic reprogramming toward a Warburg phenotype occurred as a result of contact with prostate cancer cells. Intercellular contact activated the stromal fibroblasts, triggering increased expression of glucose transporter GLUT1, lactate production, and extrusion of lactate by de novo expressed monocarboxylate transporter-4 (MCT4). Conversely, prostate cancer cells, upon contact with CAFs, were reprogrammed toward aerobic metabolism, with a decrease in GLUT1 expression and an increase in lactate upload via the lactate transporter MCT1. Metabolic reprogramming of both stromal and cancer cells was under strict control of the hypoxia-inducible factor 1 (HIF1), which drove redox- and SIRT3-dependent stabilization of HIF1 in normoxic conditions. Prostate cancer cells gradually became independent of glucose consumption, while developing a dependence on lactate upload to drive anabolic pathways and thereby cell growth. In agreement, pharmacologic inhibition of MCT1-mediated lactate upload dramatically affected prostate cancer cell survival and tumor outgrowth. Hence, cancer cells allocate Warburg metabolism to their corrupted CAFs, exploiting their byproducts to grow in a low glucose environment, symbiotically adapting with stromal cells to glucose availability. Cancer Res; 72(19); 5130–40. ©2012 AACR.
Simultaneous Control of Diabetes Mellitus, Hypertension, and Hyperlipidemia in 2 Health Systems
Authors: Schroeder Emily B. , Hanratty Rebecca , Beaty Brenda L. , Bayliss Elizabeth A. , Havranek Edward P. , Steiner John F. 
Published: August 2012

Background—
Many individuals with diabetes mellitus, hypertension, and hyperlipidemia have difficulty achieving control of all 3 conditions. We assessed the incidence and duration of simultaneous control of hyperglycemia, blood pressure, and low-density lipoprotein cholesterol in patients from 2 health care systems in Colorado.

Methods and Results—

We performed a retrospective cohort study of adults at Denver Health and Kaiser Permanente Colorado with diabetes mellitus, hypertension, and hyperlipidemia from 2000 through 2008. Over a median of 4.0 and 4.4 years, 16% and 30% of individuals at Denver Health and Kaiser Permanente achieved the primary outcome (simultaneous control with a glycosylated hemoglobin (HbA
1c
) <7.0%, blood pressure <130/80 mm Hg, and low-density lipoprotein cholesterol <100 mg/dL), respectively. With less strict goals (HbA
1c
<8.0%, blood pressure <140/90 mm Hg, and low-density lipoprotein cholesterol <130 mg/dL), 44% and 70% of individuals at Denver Health and Kaiser Permanente achieved simultaneous control. Sociodemographic characteristics (increasing age, white ethnicity), and the presence of cardiovascular disease or other comorbidities were significantly but not strongly predictive of achieving simultaneous control in multivariable models. Simultaneous control was less likely as severity of the underlying conditions increased, and more likely as medication adherence increased.

Conclusions—
Simultaneous control of diabetes mellitus, hypertension, and hyperlipidemia was uncommon and generally transient. Less stringent goals had a relatively large effect on the proportion achieving simultaneous control. Individuals who simultaneously achieve multiple treatment goals may provide insight into self-care strategies for individuals with comorbid health conditions.
Bionic Baroreceptor Corrects Postural Hypotension in Rats With Impaired Baroreceptor
Authors: Hosokawa Kazuya , Ide Tomomi , Tobushi Tomoyuki , Sakamoto Kazuo , Onitsuka Ken , Sakamoto Takafumi , Fujino Takeo , Saku Keita , Sunagawa Kenji 
Published: August 2012

Background—
Impairment of the arterial baroreflex causes orthostatic hypotension. Arterial baroreceptor sensitivity degrades with age. Thus, an impaired baroreceptor plays a pivotal role in orthostatic hypotension in most elderly patients. There is no effective treatment for orthostatic hypotension. The aims of this investigation were to develop a bionic baroreceptor (BBR) and to verify whether it corrects postural hypotension.

Methods and Results—

The BBR consists of a pressure sensor, a regulator, and a neurostimulator. In 35 Sprague-Dawley rats, we vascularly and neurally isolated the baroreceptor regions and attached electrodes to the aortic depressor nerve for stimulation. To mimic impaired baroreceptors, we maintained intracarotid sinus pressure at 60 mm Hg during activation of the BBR. Native baroreflex was reproduced by matching intracarotid sinus pressure to the instantaneous pulsatile aortic pressure. The encoding rule for translating intracarotid sinus pressure into stimulation of the aortic depressor nerve was identified by a white noise technique and applied to the regulator. The open-loop arterial pressure response to intracarotid sinus pressure (n=7) and upright tilt–induced changes in arterial pressure (n=7) were compared between native baroreceptor and BBR conditions. The intracarotid sinus pressure–arterial pressure relationships were comparable. Compared with the absence of baroreflex, the BBR corrected tilt-induced hypotension as effectively as under native baroreceptor conditions (native, −39±5 mm Hg; BBR, −41±5 mm Hg; absence, −63±5 mm Hg;
P
<0.05).

Conclusions—
The BBR restores the pressure buffering function. Although this research demonstrated feasibility of the BBR, further research is needed to verify its long-term effect and safety in larger animal models and humans.
Retrospective Multicenter Study of Solitaire FR for Revascularization in the Treatment of Acute Ischemic Stroke
Authors: Dávalos Antoni , Pereira Vitor Mendes , Chapot René , Bonafé Alain , Andersson Tommy , Gralla Jan 
Published: August 2012

Background and Purpose—
The purpose of this study was to evaluate safety and efficacy of the Solitaire FR device in the treatment of patients with acute ischemic stroke secondary to large artery occlusion.

Methods—
We conducted a retrospective study of consecutive patients presenting with acute ischemic stroke treated with Solitaire FR as the first-line device to restore blood flow in 6 experienced European centers. This study was entirely funded and supported by Coviden Neurovascular. An independent Corelab determined modified Thrombolysis in Cerebral Infarction scores on the preprocedure and postprocedure angiograms. Complete revascularization was defined as modified Thrombolysis in Cerebral Infarction 2b or 3 post-Solitaire FR device use. Symptomatic intracranial hemorrhage was defined as parenchymal hemorrhage Type 2 associated with a decline of ≥4 points in the National Institutes of Health Stroke Scale score within 24 hours or causing death. Favorable functional outcome was considered as modified Rankin Scale score ≤2 at Day 90.

Results—

We studied 141 patients (mean age, 66 years; median National Institutes of Health Stroke Scale, 18); 74 patients received intravenous tissue-type plasminogen activator before endovascular treatment. Complete revascularization was achieved in 120 of 142 occlusion sites (85%) and good outcome in 77 of 141 (55%) patients. Good outcome was more frequent in patients treated with intravenous tissue-type plasminogen activator than in those without (66% versus 42%;
P
<0.01). Symptomatic intracranial hemorrhage was reported in 5 patients (4%) and 29 of 141 (20%) patients died or were lost during follow-up (3 cases).

Conclusions—
This retrospective study with centralized evaluation shows that the use of Solitaire FR is safe and achieves good revascularization rates and functional outcomes in patients with acute ischemic stroke and large artery occlusion.
Glutamate gene polymorphisms predict brain volumes in multiple sclerosis
Authors: Strijbis Eva MM , Inkster Becky , Vounou Maria , Naegelin Yvonne , Kappos Ludwig , Radue Ernst-Wilhelm , Matthews Paul M , Uitdehaag Bernard MJ , Barkhof Frederik , Polman Chris H , Montana Giovanni , Geurts Jeroen JG 
Published: August 2012

Background: Several genetic markers have been associated with multiple sclerosis (MS) susceptibility; however, uncovering the genetic aetiology of the complex phenotypic expression of MS has been more difficult so far. The most common approach in imaging genetics is based on mass-univariate linear modelling (MULM), which faces several limitations. Objective: Here we apply a novel multivariate statistical model, sparse reduced-rank regression (sRRR), to identify possible associations of glutamate related single nucleotide polymorphisms (SNPs) and multiple MRI-derived phenotypes in MS. Methods: Seven phenotypes related to brain and lesion volumes for a total number of 326 relapsing–remitting and secondary-progressive MS patients and a total of 3809 glutamate related and control SNPs were analysed with sRRR, which resulted in a ranking of SNPs in decreasing order of importance (‘selection probability’). Lasso regression and MULM were used as comparative statistical techniques to assess consistency of the most important associations over different statistical models. Results: Five SNPs within the NMDA-receptor-2A-subunit (GRIN2A) domain were identified by sRRR in association with normalized brain volume (NBV), normalized grey matter volume and normalized white matter volume (NMWM). The association between GRIN2A and both NBV and NWMV was confirmed in MULM and Lasso analysis. Conclusions: Using a novel, multivariate regression model confirmed by two other statistical approaches we show associations between GRIN2A SNPs and phenotypic variation in NBV and NWMV in this first exploratory study. Replications in independent datasets are now necessary to validate these findings.