bluuebunny/crossref_metadata_2025 huggingface dataset:
Promoting Gender Equality: The Role of Ideology, Power, and Control in the Link Between Land Ownership and Violence in Nicaragua
Authors: Grabe Shelly
Published: December 2010

Scholars have argued that institutional inequities and control over resources are linked to gender‐based violence. However, psychologists have yet to reposition their research questions to examine how structural inequities lead to power imbalances and gender‐based norms that perpetuate threats to women's health and safety. This study provides a theoretical framework for, and an examination of, hypotheses surrounding the role of land ownership in shifting gender relations and women's receipt of violence that have been posed in the literature but never empirically tested. Surveys conducted in rural Nicaragua revealed that land ownership among women challenges traditional gender ideology and increases women's power and control within the marital relationship, which in turn, reduces levels of violence. The findings have important implications for the discussion of gender‐based violence in the context of development and for initiatives that can lead to more equitable policies for women. The study puts psychology at the crossroads of women's human rights, globalization, and social change by putting forth a novel model for understanding inequality and providing an empirical framework for social justice.
Students’ Perception of Interdisciplinary, Problem‐Based Learning in a Food Biotechnology Course
Authors: Ng Betsy L.L. , Yap Kueh C. , Hoh Yin K.
Published: December 2010

Abstract:  Students’ perception of 8 criteria (rationale of the problem; interdisciplinary learning; facilitator asked essential questions; learner's skills; assessments; facilitation procedures; team's use of resources [team collaboration], and facilitator within a problem‐based learning context) were assessed for a food biotechnology course that was part of a 3rd year biotechnology program. The mean score for “perceived learner's skills” was the lowest whereas those for “facilitation” and “facilitator” were the highest. Selected qualitative comments from students were also analyzed. This study demonstrated interdisciplinary learning as the students could make meaningful connections across different science disciplines. Further investigation is needed to develop possible strategies to accommodate the challenges in making meaningful connections across science disciplines as well as to develop a defined hybrid method for analysis of students’ responses.
Development of an Evaluation Tool for Online Food Safety Training Programs
Authors: Neal Jr Jack A. , Murphy Cheryl A. , Crandall Philip G. , O’Bryan Corliss A. , Keifer Elizabeth , Ricke Steven C.
Published: December 2010

Abstract:  The objective of this study was to provide the person in charge and food safety instructors an assessment tool to help characterize, identify strengths and weaknesses, determine the completeness of the knowledge gained by the employee, and evaluate the level of content presentation and usability of current retail food safety training platforms. An existing evaluation tool was modified to assess online food safety training programs that contained 5 areas of emphasis: content and instruction, learners, job transfer, design and packaging, and operation. Participation included watching 3 food safety training modules and afterwards evaluate what degree the module content met objectives. More than 85% of the participants responded positively to the scale‐based items of the course evaluation. Items addressing the content and instruction received positive responses. The assessment tool helped panelists to objectively evaluate an online food safety training program that provided numeric data for a valid comparison.
Structural Priming as Structure‐Mapping: Children Use Analogies From Previous Utterances to Guide Sentence Production
Authors: Goldwater Micah B. , Tomlinson Marc T. , Echols Catharine H. , Love Bradley C.
Published: December 2010

What mechanisms underlie children’s language production? Structural priming—the repetition of sentence structure across utterances—is an important measure of the developing production system. We propose its mechanism in children is the same as may underlie analogical reasoning: structure‐mapping. Under this view, structural priming is the result of making an analogy between utterances, such that children map semantic and syntactic structure from previous to future utterances. Because the ability to map relationally complex structures develops with age, younger children are less successful than older children at mapping both semantic and syntactic relations. Consistent with this account, 4‐year‐old children showed priming only of semantic relations when surface similarity across utterances was limited, whereas 5‐year‐olds showed priming of both semantic and syntactic structure regardless of shared surface similarity. The priming of semantic structure without syntactic structure is uniquely predicted by the structure‐mapping account because others have interpreted structural priming as a reflection of developing syntactic knowledge.
A comparison of the biochemical modifications caused by toxic and non‐toxic protein oligomers in cells
Authors: Zampagni Mariagioia , Cascella Roberta , Casamenti Fiorella , Grossi Cristina , Evangelisti Elisa , Wright Daniel , Becatti Matteo , Liguri Gianfranco , Mannini Benedetta , Campioni Silvia , Chiti Fabrizio , Cecchi Cristina
Published: December 2010

Peptides and proteins can convert from their soluble forms into highly ordered fibrillar aggregates, giving rise to pathological conditions ranging from neurodegenerative disorders to systemic amyloidoses. It is increasingly recognized that protein oligomers forming early in the process of fibril aggregation represent the pathogenic species in protein deposition diseases. The N‐terminal domain of the HypF protein from Escherichia coli (HypF‐N) has previously been shown to form, under distinct conditions, two types of HypF‐N oligomers with indistinguishable morphologies but distinct structural features at the molecular level. Only the oligomer type exposing hydrophobic surfaces and possessing sufficient structural plasticity is toxic (type A), whereas the other type is benign to cultured cells (type B). Here we show that only type A oligomers are able to induce a Ca2+ influx from the cell medium to the cytosol, to penetrate the plasma membrane, to increase intracellular reactive oxygen species production, lipid peroxidation and release of intracellular calcein, resulting in the activation of the apoptotic pathway. Remarkably, these oligomers can also induce a loss of cholinergic neurons when injected into rat brains. By contrast, markers of cellular stress and viability were unaffected in cultured and rat neuronal cells exposed to type B oligomers. The analysis of the time scales of such effects indicates that the difference of toxicity between the two oligomer types involve the early events of the toxicity cascade, shedding new light on the mechanism of action of protein oligomers and on the molecular targets for the therapeutic intervention against protein deposition diseases.
Therapeutic effects of human STRO‐3‐selected mesenchymal precursor cells and their soluble factors in experimental myocardial ischemia
Authors: See Fiona , Seki Tetsunori , Psaltis Peter J. , Sondermeijer Hugo P. , Gronthos Stan , Zannettino Andrew C.W. , Govaert Klaas M. , Schuster Michael D. , Kurlansky Paul A. , Kelly Darren J. , Krum Henry , Itescu Silviu
Published: December 2010

Stromal precursor antigen (STRO)‐3 has previously been shown to identify a subset of adult human bone marrow (BM)‐derived mesenchymal lineage precursors, which may have cardioprotective potential. We sought to characterize STRO‐3‐immunoselected and culture‐expanded mesenchymal precursor cells (MPCs) with respect to their biology and therapeutic potential in myocardial ischemia. Immunoselection of STRO‐3+ MPCs enriched for fibroblastic colony forming units from unfractionated BM mononuclear cells (MNCs). Compared to mesenchymal stem cells conventionally isolated by plastic adherence, MPCs demonstrated increased proliferative capacity during culture expansion, expressed higher levels of early ‘stem cell’ markers and various pro‐angiogenic and cardioprotective cytokines, and exhibited greater trilineage developmental efficiency. Intramyocardial injection of MPCs into a rat model of myocardial infarction (MI) promoted left ventricular recovery and inhibited left ventricular dilatation. These beneficial effects were associated with cardioprotective and pro‐angiogenic effects at the tissue level, despite poor engraftment of cells. Treatment of MI rats with MPC‐conditioned medium (CM) preserved left ventricular function and dimensions, reduced myocyte apoptosis and fibrosis, and augmented neovascularization, involving both resident vascular cells and circulating endothelial progenitor cells (EPCs). Profiling of CM revealed various cardioprotective and pro‐angiogenic factors, which had biological activity in cultures of myocytes, tissue‐resident vascular cells and EPCs. Prospective immunoselection of STRO‐3+ MPCs from BM MNCs conferred advantage in maintaining a population of immature MPCs during ex vivo expansion. Transplantation of culture‐expanded MPCs into the post‐MI heart resulted in therapeutic benefit, attributable at least in part to paracrine mechanisms of action. Thus, MPCs represent a promising therapy for myocardial ischemia.
REIRRADIATION OF RECURRENT CANINE NASAL TUMORS
Authors: BOMMARITO DAVID A. , KENT MICHAEL S. , SELTING KIM A. , HENRY CAROLYN J. , LATTIMER JIMMY C.
Published: December 2010

Canine nasal tumors are typically treated with radiation therapy but most patients develop local recurrence. Our purpose was to evaluate tumor and normal tissue response to reirradiation in nine dogs. The median dose delivered with the first protocol was 50 Gy (range 44–55 Gy) and the median fraction number was 18 (range 15–20). For the second protocol, the median dose was lower intentionally, median of 36 Gy (range 23–44 Gy), without changing the median fraction number of 18 (range 14–20) to avoid late effects. The median time between protocols was 539 days (range 258–1652 days). Median survival was 927 days (95% confidence interval [CI] 423–1767 days). Median time to progression following the first and second courses was 513 days (95% CI 234–1180 days) and 282 days (95% CI 130–453 days), respectively. These were not significantly different (P=0.086). The qualitative response assessment was better for the first course compared with the second (P=0.018). Severity and timing of skin, mucous membrane, and ocular effects were similar for early side effects between the two courses (P>0.05 for all comparisons). All dogs experienced some late side effects, with two out of nine being classified as severe. These severe effects were blindness in each dog, possibly related to tumor recurrence. Reirradiation of canine nasal tumors resulted in a second clinical remission in eight of nine dogs, although the second response was less complete. Acute and late effects for seven of nine patients were not life threatening, indicating that reirradiation of canine nasal tumors may be a viable treatment option after recurrence.
Going beyond the author: what retellings tell us about comprehending narrative and expository texts
Authors: Kucer Stephen B.
Published: December 2010

This research examines the nature of comprehended meanings that do not match those of the author. These meanings were generated by two groups of fourth graders after reading a narrative or expository text. Readers read their respective texts aloud, followed by a recall and probes. Reading behaviours were examined to establish that processing difficulties did not significantly impact reader comprehension. Retold clauses that did not match those in the text were classified using a retelling taxonomy: substitution, addition, summary, conflict, rearrangement, omission. It was discovered that both groups of readers went beyond the information given, approximately 18 per cent of the time for the narration and 59 per cent of the time for the exposition. Additionally, the profiles of this information varied between the two groups. Narrative retellings contained a high percentage of conflicts, with very few substitutions, summaries or rearrangement of ideas. In contrast, expository retellings had significant numbers of substitutions and summaries, with fewer additions and rearrangements. It is hypothesised that reader background knowledge accounted for the variation in the retelling profiles and that this background facilitated as well as inhibited understanding. Given such variation even among these proficient readers, teachers not only need to help students develop background knowledge related to the text, but also encourage readers to cross‐check their understandings with the text. Interestingly, this cross‐checking is especially needed when there is an alignment between reader background and text content.
Enhancing the protein production levels in Escherichia coli with a strong promoter
Authors: Tegel Hanna , Ottosson Jenny , Hober Sophia
Published: December 2010

In biotechnology, the use of Escherichia coli for recombinant protein production has a long tradition, although the optimal production conditions for certain proteins are still not evident. The most favorable conditions for protein production vary with the gene product. Temperature and induction conditions represent parameters that affect total protein production, as well as the amount of soluble protein. Furthermore, the choice of promoter and bacterial strain will have large effects on the production of the target protein. In the present study, the effects of three different promoters (T7, trc and lacUV5) on E. coli production of target proteins with different characteristics are presented. The total amount of target protein as well as the amount of soluble protein were analyzed, demonstrating the benefits of using a strong promoter such as T7. To understand the underlying causes, transcription levels have been correlated with the total amount of target protein and protein solubility in vitro has been correlated with the amount of soluble protein that is produced. In addition, the effects of two different E. coli strains, BL21(DE3) and Rosetta(DE3), on the expression pattern were analyzed. It is concluded that the regulation of protein production is a combination of the transcription and translation efficiencies. Other important parameters include the nucleotide‐sequence itself and the solubility of the target protein.
Perspectives of Iranian male nursing students regarding the role of nursing education in developing a professional identity: A content analysis study
Authors: VAISMORADI Mojtaba , SALSALI Mahvash , AHMADI Fazlollah
Published: December 2010

Aim:  The purpose of the present study was to explore the perspectives of Iranian male nursing students regarding the role of nursing education in developing a professional identity.

Methods:  A qualitative design, based on the content analysis approach, was used to collect the data and analyze the perspectives of 14 Iranian male nursing students who were chosen by using a purposive sampling strategy. After the selection of the participants, semistructured interviews were held in order to collect the data.

Results:  During the data analysis, three main themes emerged: “reality–expectation incompatibility”, “being supported by the educational system”, and “nursing image rectification”. The second theme consisted of two categories: “feeling trusted” and “being defended”.

Conclusions:  This study will be useful to nurse educators and administrators in relation to what constitutes nursing students' professional identity within the Iranian culture and context and how nursing education can play an effective role in developing their professional identity in order to devise strategies to attract male students to the nursing profession and promote their retention after graduation.
The Association Between Erectile Dysfunction and Depressive Symptoms in Men Treated for Prostate Cancer
Authors: Nelson Christian J. , Mulhall John P. , Roth Andrew J.
Published: December 2010

Introduction

The relationship between erectile dysfunction (ED) and depressive symptoms is well established. However, this relationship is not well explored in men with prostate cancer. Limited data suggest men with prostate cancer may experience less ED bother than men with ED who do not have prostate cancer, implying that ED and depressive symptoms may not be associated in men with prostate cancer.

Aim

To determine if ED is associated with depressive symptoms in men with prostate cancer.

Main Outcome Measures

Assessments of quality-of-life (The Functional Assessment of Cancer Therapy [FACT-P]), anxiety/depression (Hospital Anxiety and Depression Scale [HADS]), and erectile function. Erectile function was measured with one question from the FACT-P similar to that used by the Massachusetts Male Aging Study.

Methods

Men with prostate cancer, and naïve of hormone treatment, completed the study questionnaires at a single time point.

Results

The average age of the 339 men was 67 ± 10 years. The average time since diagnosis was 3.9 ± 3 years. When answering the question, “I am able to have and maintain an erection” on a 1 to 5 scale (5 representing the best function), the mean score was 2 indicating “a little bit.” On univariate analysis, erectile function and depression were associated, r = −0.12, P < 0.05. Other variables associated with depression were marital status, r = 0.11, P < 0.05; anxiety scores, r = 0.56, P < 0.01; and social support, r = −0.42, P < 0.01. On multivariate analysis, erectile function remained a significant predictor of depression, beta = −0.10, P < 0.05.

Conclusions

Erectile function was associated with depressive symptoms in both univariate and multivariate analysis, indicating that ED is independently associated with depressive symptoms even though patients were approximately 4 years post diagnosis. These cross-sectional data suggest ED in men with prostate cancer can have lasting psychological effects.
The Noradrenergic Action in Antidepressant Treatments: Pharmacological and Clinical Aspects
Authors: Dell’Osso Bernardo , Palazzo M. Carlotta , Oldani Lucio , Altamura A. Carlo
Published: December 2010

Even though noradrenaline has been recognized as one of the key neurotransmitters in the pathophysiology of major depression (MD), noradrenergic compounds have been less extensively utilized in clinical practice, compared to selective serotonin reuptake inhibitors (SSRIs). The development of the first selective noradrenergic reuptake inhibitor (NRI), Reboxetine, has not substantially changed the state of the art. In addition, Atomoxetine, a relatively pure NRI used for the treatment of ADHD, has shown mixed results when administered in augmentation to depressed subjects. Through a Medline search from 2000 to 2010, the present article provides an updated overview of the main pharmacological and clinical aspects of antidepressant classes that, partially or selectively, act on the noradrenergic systems. The noradrenergic action plays an important clinical effect in different antidepressant classes, as confirmed by the efficacy of dual action antidepressants such as the serotonin noradrenaline reuptake inhibitors (SNRIs), the noradrenergic and dopaminergic reuptake inhibitor (NDRI) Bupropion, and other compounds (e.g., Mianserin, Mirtazapine), which enhance the noradrenergic transmission. In addition, many tricyclics, such as Desipramine and Nortriptyline, have prevalent noradrenergic effect. Monoamine oxidase inhibitors (MAOIs), moreover, block the breakdown of serotonin, noradrenaline, dopamine and increase the availability of these monoamines. A novel class of antidepressants—the triple reuptake inhibitors—is under development to selectively act on serotonin, noradrenaline, and dopamine. Finally, the antidepressant effect of the atypical antipsychotic Quetiapine, indicated for the treatment of bipolar depression, is likely to be related to the noradrenergic action of its metabolite Norquetiapine. Even though a pure noradrenergic action might not be sufficient to obtain a full antidepressant effect, a pronoradrenergic action represents an important element for increasing the efficacy of mixed action antidepressants. In particular, the noradrenergic action seemed to be related to the motor activity, attention, and arousal.
Peritoneal Dialysis in Cats with Acute Kidney Injury: 22 Cases (2001–2006)
Authors: Cooper R.L. , Labato M.A.
Published: December 2010

Background: Peritoneal dialysis (PD) has been described for use in animals with acute kidney injury refractory to fluid therapy. However, no study has examined the use of PD in a large group of cats.

Hypothesis: PD is an important adjunctive therapy to treat acute kidney injury in cats.

Animals: The medical records of 22 cats with acute kidney injury that had received PD were examined. Animals were excluded if acute uremia was a result of postrenal causes such as uroabdomen or urethral obstruction.

Methods: Medical records were reviewed for the following: indication for PD, outcome, number of cycles performed, survival time, and predialysis and postdialysis results for blood urea nitrogen (BUN), creatinine, potassium, chloride, sodium, phosphorus, total protein, and albumin concentrations, and urine output.

Results:

Indications for PD include acute‐on‐chronic kidney injury, acute kidney injury caused by toxins, bilateral ureteroliths, bilateral ureteral ligation as a complication of ovariohysterectomy, and unknown causes. The median survival time for all cats on PD was 4 days, although the median survival time for the cats that were discharged was 774 days. The most common complications were dialysate retention and sequestration of dialysate SC. There was a significant (P< .05) decrease between predialysis and postdialysis results for BUN, creatinine, potassium, phosphorus, total protein, and albumin concentrations. There was a significant (P< .05) difference in survival times between sexes.

Conclusions and Clinical Importance: PD is an effective option for treatment of cats with acute kidney injury refractory to fluid therapy.
Cosmogenic radioisotopes in the Almahata Sitta ureilite
Authors: TARICCO Carla , BHANDARI Narendra , COLOMBETTI Paolo , ROMERO Alberto , VIVALDO Gianna , SINHA Neeharika , JENNISKENS Peter , SHADDAD Muawia H. , BALLABH G. M.
Published: December 2010

Abstract– Asteroid 2008 TC3 was predicted to fall in Sudan on October 7, 2008, and 2 months later, 15 meteorite fragments were recovered from the Nubian Desert. Most of these fragments were classified as polymict ureilites. In the largest ureilitic fragment #15, weighing 75 g, we have measured six gamma emitting radionuclides (46Sc, 57Co, 54Mn, 22Na, 60Co, and 26Al) by nondestructive whole rock counting using a sensitive gamma‐ray spectrometer. The activities of 60Co, produced mainly by neutron capture in cobalt, and 26Al indicate that fragment #15 was located at a depth of 41 ± 14 cm inside the 1.5–2 m radius asteroid. The activity of other radionuclides is also consistent with this shielding depth within the asteroid. The 22Na/26Al activity ratio is higher than expected for the average cosmic ray flux, probably due to the unusually prolonged solar minimum before the fall.
Pharmacodynamic assessment of vancomycin–rifampicin combination against methicillin resistant Staphylococcus aureus biofilm: a parametric response surface analysis
Authors: Salem Ahmed H , Elkhatib Walid F , Noreddin Ayman M
Published: December 2010

Objectives

A combination of vancomycin and rifampicin (rifampin) is commonly used to treat staphylococcal infections but its efficacy against methicillin-resistant Staphylococcus aureus (MRSA) biofilm is controversial. The objective of this study was to use a recently developed quantitative methodology to characterise the killing effect of vancomycin and rifampin combination against MRSA biofilm.

Methods

MRSA biofilm was exposed to escalating concentrations of vancomycin and rifampin and the viability of the biofilm-ensconced bacteria was evaluated. ADAPT II was used to model the concentration–effect relationship and determine the optimal sampling concentrations. Combination experiments were then conducted and the observations were compared with a simulated response surface representing null interaction. Finally, the pharmacodynamic interaction index (PDI) was computed as the ratio of the volumes under the observed and simulated surfaces.

Key findings

In the combination experiments, all observations showed an inferior antibacterial effect to what is expected under null interaction assumption and the PDI was estimated to be 3.36 (95% CI, 3.25 to 3.46).

Conclusions

The results of the study demonstrate in-vitro antagonism between vancomycin and rifampin against MRSA biofilm. The quantitative approach employed to quantify the antibacterial effect of the combination provides a scientific rationale for further in-vivo investigations that should allow a better understanding of the therapeutic potential of this combination in biofilm-associated MRSA infections.
Auranofin Protects against Anthrax Lethal Toxin-Induced Activation of the Nlrp1b Inflammasome
Authors: Newman Zachary L. , Sirianni Nicole , Mawhinney Christina , Lee Margaret S. , Leppla Stephen H. , Moayeri Mahtab , Johansen Lisa M.
Published: December 2010

Anthrax lethal toxin (LT) is the major virulence factor forBacillus anthracis. The lethal factor (LF) component of this bipartite toxin is a protease which, when transported into the cellular cytoplasm, cleaves mitogen-activated protein kinase kinase (MEK) family proteins and induces rapid toxicity in mouse macrophages through activation of the Nlrp1b inflammasome. A high-throughput screen was performed to identify synergistic LT-inhibitory drug combinations from within a library of approved drugs and molecular probes. From this screen we discovered that auranofin, an organogold compound with anti-inflammatory activity, strongly inhibited LT-mediated toxicity in mouse macrophages. Auranofin did not inhibit toxin transport into cells or MEK cleavage but inhibited both LT-mediated caspase-1 activation and caspase-1 catalytic activity. Thus, auranofin inhibited LT-mediated toxicity by preventing activation of the Nlrp1b inflammasome and the downstream actions that occur in response to the toxin. Idebenone, an analog of coenzyme Q, synergized with auranofin to increase its protective effect. We found that idebenone functions as an inhibitor of voltage-gated potassium channels and thus likely mediates synergy through inhibition of the potassium fluxes which have been shown to be required for Nlrp1b inflammasome activation.
Diversity of Clavulanic Acid-Inhibited Extended-Spectrum β-Lactamases inAeromonasspp. from the Seine River, Paris, France
Authors: Girlich Delphine , Poirel Laurent , Nordmann Patrice
Published: December 2010

EnvironmentalAeromonassp. isolates resistant to ceftazidime were recovered during an environmental survey performed with water samples from the Seine River, in Paris, France, in November 2009. Selected isolates were identified by sequencing of the 16S rRNA andrpoBgenes. PCR and cloning experiments were used to identify broad-spectrum-β-lactamase-encoding genes and their genetic context. Clavulanic acid-inhibited extended-spectrum-β-lactamase (ESBL) genes were identified in 71% of theAeromonassp. isolates. A variety of ESBL genes were detected, includingblaVEB-1a,blaSHV-12,blaPER-1,blaPER-6,blaTLA-2, andblaGES-7, suggesting an aquatic reservoir of those ESBL genes. Moreover, the repeated elements and different insertion sequences were identified in association with theblaPER-6and theblaVEB-1agenes, respectively, indicating a wide diversity of mobilization events, makingAeromonasspp. a vehicle for ESBL dissemination.
Investigation of the Potential for Mutational Resistance to XF-73, Retapamulin, Mupirocin, Fusidic Acid, Daptomycin, and Vancomycin in Methicillin-Resistant
Staphylococcus aureus
Isolates during a 55-Passage Study
Authors: Farrell David J. , Robbins Marion , Rhys-Williams William , Love William G.
Published: December 2010

XF-73 is a dicationic porphyrin drug with rapid Gram-positive antibacterial activity currently undergoing clinical trials for the nasal decolonization of
Staphylococcus aureus
, including methicillin-resistant
Staphylococcus aureus
(MRSA). In multistep (55-passage) resistance selection studies in the presence of subinhibitory concentrations of XF-73, retapamulin, mupirocin, fusidic acid, and vancomycin against four Network on Antimicrobial Resistance in
Staphylococcus aureus
MRSA strains, there was no >4-fold increase in the MIC for XF-73 after 55 passages. In contrast, there was an increase in the MICs for retapamulin (from 0.25 μg/ml to 4 to 8 μg/ml), for mupirocin (from 0.12 μg/ml to 16 to 512 μg/ml), for fusidic acid (from 0.12 μg/ml to 256 μg/ml), and for vancomycin (from 1 μg/ml to 8 μg/ml in two of the four strains tested). Further investigations using
S. aureus
NRS384 (USA300) and daptomycin demonstrated a 64-fold increase in the MIC after 55 passages (from 0.5 μg/ml to 32 μg/ml) with a >4-fold increase in the MIC obtained after only five passages. Sequencing analysis of selected isolates confirmed previously reported point mutations associated with daptomycin resistance. No cross-resistance to XF-73 was observed with the daptomycin-resistant strains, suggesting that whereas the two drugs act on the bacterial cell membrane, their specific site of action differs. XF-73 thus represents the first in a new class of antibacterial drugs, which (unlike the comparator antibiotics) after 55 passages exhibited a ≤4-fold increase in MIC against the strains tested. Antibacterial drugs with a low propensity for inducing bacterial resistance are much needed for the prevention and treatment of multidrug-resistant bacteria both within and outside the hospital setting.
Biochemical and Structural Characterization of the Subclass B1 Metallo-β-Lactamase VIM-4
Authors: Lassaux Patricia , Traoré Daouda A. K. , Loisel Elodie , Favier Adrien , Docquier Jean-Denis , Sohier Jean Sébastien , Laurent Clémentine , Bebrone Carine , Frère Jean-Marie , Ferrer Jean-Luc , Galleni Moreno
Published: December 2010

The metallo-β-lactamase VIM-4, mainly found in
Pseudomonas aeruginosa
or
Acinetobacter baumannii
, was produced in
Escherichia coli
and characterized by biochemical and X-ray techniques. A detailed kinetic study performed in the presence of Zn
2+
at concentrations ranging from 0.4 to 100 μM showed that VIM-4 exhibits a kinetic profile similar to the profiles of VIM-2 and VIM-1. However, VIM-4 is more active than VIM-1 against benzylpenicillin, cephalothin, nitrocefin, and imipenem and is less active than VIM-2 against ampicillin and meropenem. The crystal structure of the dizinc form of VIM-4 was solved at 1.9 Å. The sole difference between VIM-4 and VIM-1 is found at residue 228, which is Ser in VIM-1 and Arg in VIM-4. This substitution has a major impact on the VIM-4 catalytic efficiency compared to that of VIM-1. In contrast, the differences between VIM-2 and VIM-4 seem to be due to a different position of the flapping loop and two substitutions in loop 2. Study of the thermal stability and the activity of the holo- and apo-VIM-4 enzymes revealed that Zn
2+
ions have a pronounced stabilizing effect on the enzyme and are necessary for preserving the structure.
Contribution of the Rgg Transcription Regulator to Metabolism and Virulence ofStreptococcus suisSerotype 2
Authors: Zheng Feng , Ji Hongfeng , Cao Min , Wang Changjun , Feng Youjun , Li Ming , Pan Xiuzhen , Wang Jing , Qin Yuehong , Hu Fuquan , Tang Jiaqi
Published: December 2010

The Rgg-like regulators, a family of transcription factors commonly found in many Gram-positive bacteria, play multiple roles, especially in the control of pathogen virulence. Here, we report anrgghomologue from a Chinese isolate, 05ZYH33, ofStreptococcus suisserotype 2 (SS2). Deletion of thergggene in SS2 increased its adhesion to Hep-2 cells and hemolytic activityin vitro. Significantly, inactivation of thergggene attenuated SS2 virulence in an experimental piglet infection model. Using DNA microarrays and quantitative reverse transcription-PCR, we found that the Rgg regulator affects the transcriptional profile of 15.87% (n= 345) of all of the annotated chromosomal genes, including those involved in nonglucose carbohydrate metabolism, DNA recombination, protein biosynthesis, bacterial defense mechanisms, and others. It was experimentally verified that the deletion ofrggin SS2 reduced the utilization of nonglucose carbohydrates, such as lactose and maltose. In addition, thergggene was found to be associated with changes in the bacterial microscopic phenotype and growth curve. These data suggested that Rgg in SS2 is a global transcriptional regulator that plays an important role in promoting SS2 bacterial survival during pathogen-host interaction.
Interferon Regulatory Factor 7 Contributes to the Control ofLeishmania donovaniin the Mouse Liver
Authors: Beattie Lynette , Phillips Rebecca , Brown Najmeeyah , Owens Benjamin M. J. , Chauhan Neal , Dalton Jane E. , Kaye Paul M.
Published: December 2010

Optimal hepatic resistance toLeishmania donovaniin mice requires the coordinated effort of a variety of leukocyte populations that together induce activation of local macrophages to a leishmanicidal state. Although nitric oxide and reactive oxygen intermediates are potent leishmanicidal effector molecules operating in the acquired phase of immunity, there have long been suggestions that other mechanisms of leishmanicidal activity exist. We recently discovered thatIrf-7regulates a novel innate leishmanicidal response in resident splenic macrophages that line the marginal zone. Here, we tested whether this mechanism also operates in Kupffer cells, the resident macrophage population of the liver and the major target for hepatic infection byL. donovani. Comparing the Kupffer cell responsesin situin B6 and B6.Irf-7−/−mice, we found no evidence thatIrf-7affected amastigote uptake or early survival. However, we did find thatIrf-7-deficient mice had impaired acquired resistance to hepaticL. donovaniinfection. This phenotype was attributable to a reduction in the capacity of hepatic CD4+T cells, NK cells, and NKT cells to produce gamma interferon (IFN-γ) and also to defective induction of NOS2 in infected Kupffer cells. Our data therefore add interferon regulatory factor 7 (IRF-7) to the growing list of interferon regulatory factors that have effects on downstream events in the acquired cellular immune response to nonviral pathogens.
Distinct CCR2+Gr1+Cells Control Growth of theYersinia pestisΔyopMMutant in Liver and Spleen during Systemic Plague
Authors: Ye Zhan , Uittenbogaard Annette M. , Cohen Donald A. , Kaplan Alan M. , Ambati Jayakrishna , Straley Susan C.
Published: December 2010

We are using a systemic plague model to identify the cells and pathways that are undermined by the virulence protein YopM of the plague bacteriumYersinia pestis. In this study, we pursued previous findings that Gr1+cells are required to selectively limit growth of ΔyopM Y. pestisand that CD11b+cells other than polymorphonuclear leukocytes (PMNs) are selectively lost in spleens infected with parentY. pestis. When PMNs were ablated from mice, ΔyopM Y. pestisgrew as well as the parent strain in liver but not in spleen, showing that these cells are critical for controlling growth of the mutant in liver but not spleen. In mice lacking expression of the chemokine receptor CCR2, wild-type growth was restored to ΔyopM Y. pestisin both organs. In spleen, the Gr1+cells differentially recruited by parent and ΔyopM Y. pestisinfections were CCR2+Gr1+CD11b+CD11cLo-IntMAC3+iNOS+(inducible nitric oxide synthase-positive) inflammatory dendritic cells (iDCs), and their recruitment to spleen from blood was blocked when YopM was present in the infecting strain. Consistent with influx of iDCs being affected by YopM in spleen, the growth defect of the ΔyopMmutant was relieved by the parentY. pestisstrain in a coinfection assay in which the parent strain could affect the fate of the mutant intrans. In a mouse model of bubonic plague, CCR2 also was shown to be required for ΔyopM Y. pestisto show wild-type growth in skin. The data imply that YopM's pathogenic effect indirectly undermines signaling through CCR2. We propose a model for how YopM exerts its different effects in liver and spleen.
Characterization of Diverse Subvariants of the Meningococcal Factor H (fH) Binding Protein for Their Ability To Bind fH, To Mediate Serum Resistance, and To Induce Bactericidal Antibodies
Authors: Seib Kate L. , Brunelli Brunella , Brogioni Barbara , Palumbo Emmanuelle , Bambini Stefania , Muzzi Alessandro , DiMarcello Federica , Marchi Sara , van der Ende Arie , Aricó Beatrice , Savino Silvana , Scarselli Maria , Comanducci Maurizio , Rappuoli Rino , Giuliani Marzia M. , Pizza Mariagrazia
Published: December 2010

Neisseria meningitidisis a commensal of the human nasopharynx but is also a major cause of septicemia and meningitis. The meningococcal factor H binding protein (fHbp) binds human factor H (fH), enabling downregulation of complement activation on the bacterial surface. fHbp is a component of two serogroup B meningococcal vaccines currently in clinical development. Here we characterize 12 fHbp subvariants for their level of surface exposure and ability to bind fH, to mediate serum resistance, and to induce bactericidal antibodies. Flow cytometry and Western analysis revealed that all strains examined expressed fHbp on their surface to different extents and bound fH in an fHbp-dependent manner. However, differences in fH binding did not always correlate with the level of fHbp expression, indicating that this is not the only factor affecting the amount of fH bound. To overcome the issue of strain variability in fHbp expression, the MC58ΔfHbpstrain was genetically engineered to express different subvariants from a constitutive heterologous promoter. These recombinant strains were characterized for fH binding, and the data confirmed that each subvariant binds different levels of fH. Surface plasmon resonance revealed differences in the stability of the fHbp-fH complexes that ranged over 2 orders of magnitude, indicating that differences in residues between and within variant groups can influence fH binding. Interestingly, the level of survival in human sera of recombinant MC58 strains expressing diverse subvariants did not correlate with the level of fH binding, suggesting that the interaction of fHbp with fH is not the only function of fHbp that influences serum resistance. Furthermore, cross-reactive bactericidal activity was seen within each variant group, although the degree of activity varied, suggesting that amino acid differences within each variant group influence the bactericidal antibody response.
Maternal Schistosomiasis Japonica Is Associated with Maternal, Placental, and Fetal Inflammation
Authors: Kurtis Jonathan D. , Higashi Ashley , Wu Hai-Wei , Gundogan Fusun , McDonald Emily A. , Sharma Surrendra , PondTor Sunthorn , Jarilla Blanca , Sagliba Marriane Joy , Gonzal Analisa , Olveda Remigio , Acosta Luz , Friedman Jennifer F.
Published: December 2010

Schistosomes infect ∼40 million women of childbearing age and result in the elaboration of proinflammatory cytokines that have been implicated in fetal growth restriction. In murine models and two observational studies in humans, schistosome infection during pregnancy was associated with reduced birth weight, although a recent treatment trial inSchistosoma mansonidid not detect this association. We conducted an observational study among 99 pregnant women living in an area ofSchistosoma japonicumendemicity in the Philippines. We enrolled women at 32 weeks gestation and measuredS. japonicumand geohelminth infection intensity. We collected maternal peripheral blood at 32 weeks gestation and placental and cord blood at delivery to assess inflammatory status. At delivery, we collected a placental-tissue sample and measured birth weight. In multivariate models adjusted for geohelminths, maternal schistosomiasis was associated with increased levels of inflammatory cytokines in maternal peripheral (tumor necrosis factor alpha [TNF-α] and interleukin 10 [IL-10]), placental (TNF-α, IL-6, TNF-α receptor II [RII], and IL-1β), and cord (IL-1β and TNF-α RII) blood, as well as acute subchorionitis and increased TNF-α production by syncytiotrophoblasts assessed by immunohistochemistry (allP< 0.05). After adjusting for confounders, placental IL-1β, and TNF-α production by syncytiotrophoblasts was independently associated with decreased birth weight (bothP< 0.05). Our data indicate that maternal schistosomiasis results in a proinflammatory signature that is detectable in maternal, placental, and fetal compartments, and a subset of these responses are associated with decreased birth weight. This potential mechanistic link between maternal schistosomiasis and poor birth outcomes will contribute to the debate regarding treatment of maternal schistosome infections.
The Tetraspanin CD82 Is Specifically Recruited to Fungal and Bacterial Phagosomes prior to Acidification
Authors: Artavanis-Tsakonas Katerina , Kasperkovitz Pia V. , Papa Eliseo , Cardenas Michael L. , Khan Nida S. , Van der Veen Annemarthe G. , Ploegh Hidde L. , Vyas Jatin M.
Published: December 2010

CD82 is a member of the tetraspanin superfamily, whose physiological role is best described in the context of cancer metastasis. However, CD82 also associates with components of the class II major histocompatibility complex (MHC) antigen presentation pathway, including class II MHC molecules and the peptide-loading machinery, as well as CD63, another tetraspanin, suggesting a role for CD82 in antigen presentation. Here, we observe the dynamic rearrangement of CD82 after pathogen uptake by imaging CD82-mRFP1 expressed in primary living dendritic cells. CD82 showed rapid and specific recruitment toCryptococcus neoformans-containing phagosomes compared to polystyrene-containing phagosomes, similar to CD63. CD82 was also actively recruited to phagosomes containing other pathogenic fungi, includingCandida albicansandAspergillus fumigatus. Recruitment of CD82 to fungal phagosomes occurred independently of Toll-like receptor (TLR) signaling. Recruitment was not limited to fungi, as bacterial organisms, includingEscherichia coliandStaphylococcus aureus, also induced CD82 recruitment to the phagosome. CD82 intersected the endocytic pathway used by lipopolysaccharide (LPS), implicating CD82 in trafficking of small, pathogen-associated molecules. Despite its partial overlap with lysosomal compartments, CD82 recruitment toC. neoformans-containing phagosomes occurred independently of phagosome acidification. Kinetic analysis of fluorescence imaging revealed that CD82 and class II MHC simultaneously appear in the phagosome, indicating that the two proteins may be associated. Together, these data show that the CD82 tetraspanin is specifically recruited to pathogen-containing phagosomes prior to fusion with lysosomes.
Cholera Toxin Impairs the Differentiation of Monocytes into Dendritic Cells, Inducing Professional Antigen-Presenting Myeloid Cells
Authors: Veglia Filippo , Sciaraffia Ester , Riccomi Antonella , Pinto Dora , Negri Donatella R. M. , De Magistris Maria Teresa , Vendetti Silvia
Published: December 2010

Cholera toxin (CT) is a potent adjuvant for mucosal vaccination; however, its mechanism of action has not been clarified completely. It is well established that peripheral monocytes differentiate into dendritic cells (DCs) bothin vitroandin vivoand that monocytes are thein vivoprecursors of mucosal CD103−proinflammatory DCs. In this study, we asked whether CT had any effects on the differentiation of monocytes into DCs. We found that CT-treated monocytes, in the presence of granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin 4 (IL-4), failed to differentiate into classical DCs (CD14lowCD1ahigh) and acquired a macrophage-like phenotype (CD14highCD1alow). Cells differentiated in the presence of CT expressed high levels of major histocompatibility complex class I (MHC-I) and MHC-II and CD80 and CD86 costimulatory molecules and produced larger amounts of IL-1β, IL-6, and IL-10 but smaller amounts of tumor necrosis factor alpha (TNF-α) and IL-12 than did monocytes differentiated into DCs in the absence of CT. The enzymatic activity of CT was found to be important for the skewing of monocytes toward a macrophage-like phenotype (Ma-DCs) with enhanced antigen-presenting functions. Indeed, treatment of monocytes with scalar doses of forskolin (FSK), an activator of adenylate cyclase, induced them to differentiate in a dose-dependent manner into a population with phenotype and functions similar to those found after CT treatment. Monocytes differentiated in the presence of CT induced the differentiation of naïve T lymphocytes toward a Th2 phenotype. Interestingly, we found that CT interferes with the differentiation of monocytes into DCsin vivoand promotes the induction of activated antigen-presenting cells (APCs) following systemic immunization.
Spinal injury in car crashes: crash factors and the effects of occupant age
Authors: Bilston Lynne E , Clarke Elizabeth C , Brown Julie
Published: December 2010

Objective

Motor vehicle crashes are the leading cause of serious spinal injury in most developed nations. However, since these injuries are rare, systematic analyses of the crash factors that are predictive of spinal injury have rarely been performed. This study aimed to use a population-reference crash sample to identify crash factors associated with moderate to severe spinal injury, and how these vary with occupant age.

Methods

The US National Automotive Sampling System Crashworthiness Data System (NASS) data for 1993–2007 were analysed using logistic regression to identify crash factors associated with Abbreviated Injury Scale (AIS)2+ spinal injury among restrained vehicle passengers.

Results

Risk of moderate or severe spinal injury (AIS2+) was associated with higher severity crashes (OR=3.5 (95% CI 2.6 to 4.6)), intrusion into an occupant's seating position (OR=2.7 (95% CI 1.9 to 3.7)), striking a fixed object rather than another car (OR=1.7 (95% CI 1.3 to 2.1)), and use of a shoulder-only belt (OR=2.7 (95% CI 1.5 to 4.8)). Older occupants (65 years or older) were at higher risk of spinal injury than younger adults in frontal, side and rollover crashes. Children under 16 were at a lower risk of spinal injury than adults in all crash types except frontal crashes.

Conclusions

While the risk of serious spinal injury in motor vehicle crashes is low, these injuries are more common in crashes of higher severity or into fixed objects, and in the presence of intrusion. There are elevated risks of spinal injury for older occupants compared with younger adults, which may reflect changes in biomechanical tolerances with age. Children appear to be at lower risk of serious spinal injury than adults except in frontal crashes.