bluuebunny/crossref_metadata_2025_split huggingface dataset:
Antagonistic Interactions of Pseudomonas aeruginosa Antibiotic Resistance Mechanisms in Planktonic but Not Biofilm Growth
Authors: Mulet Xavier , Moyá Bartolomé , Juan Carlos , Macià María D. , Pérez José L. , Blázquez Jesús , Oliver Antonio 
Published: August 2011

ABSTRACTPseudomonas aeruginosahas an extraordinary capacity to evade the activity of antibiotics through a complex interplay of intrinsic and mutation-driven resistance pathways, which are, unfortunately, often additive or synergistic, leading to multidrug (or even pandrug) resistance. However, we show that one of these mechanisms, overexpression of the MexCD-OprJ efflux pump (driven by inactivation of its negative regulator NfxB), causes major changes in the cell envelope physiology, impairing the backbone ofP. aeruginosaintrinsic resistance, including the major constitutive (MexAB-OprM) and inducible (MexXY-OprM) efflux pumps and the inducible AmpC β-lactamase. Moreover, it also impaired the most relevant mutation-driven β-lactam resistance mechanism (constitutive AmpC overexpression), through a dramatic decrease in periplasmic β-lactamase activity, apparently produced by an abnormal permeation of AmpC out of the cell. While these results could delineate future strategies for combating antibiotic resistance in cases of acute nosocomial infections, a major drawback for the potential exploitation of the described antagonistic interaction between resistance mechanisms came from the differential bacterial physiology characteristics of biofilm growth, a hallmark of chronic infections. Although the failure to concentrate AmpC activity in the periplasm dramatically limits the protection of the targets (penicillin-binding proteins [PBPs]) of β-lactams at the individual cell level, the expected outcome for cells growing as biofilm communities, which are surrounded by a thick extracellular matrix, was less obvious. Indeed, our results showed that AmpC produced bynfxBmutants is protective in biofilm growth, suggesting that the permeation of AmpC into the matrix protects biofilm communities against β-lactams.
d
-Ala-
d
-Ser VanN-Type Transferable Vancomycin Resistance in Enterococcus faecium
Authors: Lebreton François , Depardieu Florence , Bourdon Nancy , Fines-Guyon Marguerite , Berger Pierre , Camiade Sabine , Leclercq Roland , Courvalin Patrice , Cattoir Vincent 
Published: August 2011

ABSTRACT

Enterococcus faecium
UCN71, isolated from a blood culture, was resistant to low levels of vancomycin (MIC, 16 μg/ml) but susceptible to teicoplanin (MIC, 0.5 μg/ml). No amplification was observed with primers specific for the previously described glycopeptide resistance ligase genes, but a PCR product corresponding to a gene called
vanN
was obtained using degenerate primers and was sequenced. The deduced VanN protein was related (65% identity) to the
d
-alanine:
d
-serine VanL ligase. The organization of the
vanN
gene cluster, determined using degenerate primers and by thermal asymmetric interlaced (TAIL)-PCR, was similar to that of the
vanC
operons. A single promoter upstream from the resistance operon was identified by rapid amplification of cDNA ends (RACE)-PCR. The presence of peptidoglycan precursors ending in
d
-serine and
d
,
d
-peptidase activities in the absence of vancomycin indicated constitutive expression of the resistance operon. VanN-type resistance was transferable by conjugation to
E. faecium
. This is the first report of transferable
d
-Ala-
d
-Ser-type resistance in
E. faecium
.
Prevention of Experimental Cerebral Malaria by Flt3 Ligand during Infection with Plasmodium berghei ANKA
Authors: Tamura Takahiko , Kimura Kazumi , Yuda Masao , Yui Katsuyuki 
Published: August 2011

ABSTRACTDendritic cells are the most potent antigen-presenting cells, but their roles in blood-stage malaria infection are not fully understood. We examined the effects of Flt3 ligand, a cytokine that induces dendritic cell production,in vivoon the course of infection withPlasmodium bergheiANKA. Mice treated with Flt3 ligand showed preferential expansion of CD8+dendritic cells and granulocytes, as well as lower levels of parasitemia, and were protected from the development of lethal experimental cerebral malaria (ECM). Rag2 knockout mice treated with Flt3 ligand also showed inhibition of parasitemia, suggesting that this protection was due, at least in part, to the stimulation of innate immunity. However, it was unlikely that the inhibition of ECM was due simply to the reduction in the level of parasitemia. In the peripheral T cell compartment, CD8+T cell levels were markedly increased in Flt3 ligand-treated mice after infection. These CD8+T cells expressed CD11c and upregulated CXCR3, while the expression of CD137, CD25, and granzyme B was reduced. In the brain, the number of sequestered CD8+T cells was not significantly different for treated versus untreated mice, while the proportion of CD8+T cells that produce gamma interferon (IFN-γ) and granzyme B was significantly reduced in treated mice. In addition, sequestration of parasitized red blood cells (RBCs) in the brain was reduced, suggesting that altered CD8+T cell activation and reduced sequestration of parasitized RBCs culminated in inhibition of ECM development. These results suggest that the quantitative and qualitative changes in the dendritic cell compartment are important for the pathogenesis of ECM.
The Burkholderia pseudomallei Δ
asd
Mutant Exhibits Attenuated Intracellular Infectivity and Imparts Protection against Acute Inhalation Melioidosis in Mice
Authors: Norris Michael H. , Propst Katie L. , Kang Yun , Dow Steven W. , Schweizer Herbert P. , Hoang Tung T. 
Published: August 2011

ABSTRACT

Burkholderia pseudomallei
, the cause of serious and life-threatening diseases in humans, is of national biodefense concern because of its potential use as a bioterrorism agent. This microbe is listed as a select agent by the CDC; therefore, development of vaccines is of significant importance. Here, we further investigated the growth characteristics of a recently created
B. pseudomallei
1026b Δ
asd
mutant
in vitro
, in a cell model, and in an animal model of infection. The mutant was typified by an inability to grow in the absence of exogenous diaminopimelate (DAP); upon single-copy complementation with a wild-type copy of the
asd
gene, growth was restored to wild-type levels. Further characterization of the
B. pseudomallei
Δ
asd
mutant revealed a marked decrease in RAW264.7 murine macrophage cytotoxicity compared to the wild type and the complemented Δ
asd
mutant. RAW264.7 cells infected by the Δ
asd
mutant did not exhibit signs of cytopathology or multinucleated giant cell (MNGC) formation, which were observed in wild-type
B. pseudomallei
cell infections. The Δ
asd
mutant was found to be avirulent in BALB/c mice, and mice vaccinated with the mutant were protected against acute inhalation melioidosis. Thus, the
B. pseudomallei
Δ
asd
mutant may be a promising live attenuated vaccine strain and a biosafe strain for consideration of exclusion from the select agent list.
Regulation of Chlamydial Infection by Host Autophagy and Vacuolar ATPase-Bearing Organelles
Authors: Yasir Muhammad , Pachikara Niseema D. , Bao Xiaofeng , Pan Zui , Fan Huizhou 
Published: August 2011

ABSTRACTAs arguably the most successful parasite,Chlamydiais an obligate intracellular bacterium replicating inside a vacuole of eukaryotic host cells. The chlamydial vacuole does not fuse with the defense cell organelle lysosome. We previously showed that chlamydial infection increases markers of autophagy, an innate antimicrobial activity requiring lysosomal function. However, the work presented here demonstrates that p62, an autophagy protein that is degraded in lysosomes, either remained unchanged or increased in chlamydia-infected human epithelial, mouse fibroblast, and mouse macrophage cell lines. In addition, the activities of three lysosomal enzymes analyzed were diminished in chlamydia-infected macrophages. Bafilomycin A1 (BafA), a specific inhibitor of vacuolar ATPase (vATPase) required for lysosomal function, increased the growth of the human pathogenChlamydia trachomatis(L2) in wild-type murine fibroblasts and macrophages but inhibited growth in the autophagy-deficient ATG5−/−fibroblasts. BafA exhibited only slight inhibition or no effect on L2 growth in multiple human genital epithelial cell lines. In contrast to L2, the mouse pathogenChlamydia muridarum(MoPn) was consistently inhibited by BafA in all cell lines examined, regardless of species origin and autophagy status. Finally, L2 but not MoPn grew more efficiently in the ATG5−/−cells than in wild-type cells. These results suggest that there are two types of vATPase-bearing organelles that regulate chlamydial infection: one supports chlamydial infection, while the other plays a defensive role through autophagy when cells are artificially infected with certain chlamydiae that have not been adapted to the host species.
Salmonella enterica Serovar Enteritidis Core O Polysaccharide Conjugated to H:g,m Flagellin as a Candidate Vaccine for Protection against Invasive Infection withS.Enteritidis
Authors: Simon Raphael , Tennant Sharon M. , Wang Jin Y. , Schmidlein Patrick J. , Lees Andrew , Ernst Robert K. , Pasetti Marcela F. , Galen James E. , Levine Myron M. 
Published: August 2011

ABSTRACTNontyphoidalSalmonella entericaserovars Enteritidis and Typhimurium are a common cause of gastroenteritis but also cause invasive infections and enteric fever in certain hosts (young children in sub-Saharan Africa, the elderly, and immunocompromised individuals).SalmonellaO polysaccharides (OPS) and flagellar proteins are virulence factors and protective antigens. The surface polysaccharides ofSalmonellaare poorly immunogenic and do not confer immunologic memory, limitations overcome by covalently attaching them to carrier proteins. We conjugated core polysaccharide-OPS (COPS) ofSalmonellaEnteritidis lipopolysaccharide (LPS) to flagellin protein from the homologous strain. COPS and flagellin were purified from a genetically attenuated (ΔguaBA) “reagent strain” (derived from an isolate from a patient with clinical bacteremia) engineered for increased flagellin production (ΔclpPX). Conjugates were constructed by linking flagellin monomers or polymers at random COPS hydroxyls with various polysaccharide/protein ratios by 1-cyano-4-dimethylaminopyridinium tetrafluoroborate (CDAP) or at the 3-deoxy-d-manno-octulosonic acid (KDO) terminus by thioether chemistry. Mice immunized on days 0, 28, and 56 with COPS-flagellin conjugates mounted higher anti-LPS IgG levels than mice receiving unconjugated COPS and exhibited high antiflagellin IgG; anti-LPS and antiflagellin IgG levels increased following booster doses. Antibodies generated by COPS-flagellin conjugates mediated opsonophagocytosis ofS.Enteritidis cells into mouse macrophages. Mice immunized with flagellin alone, COPS-CRM197, or COPS-flagellin conjugates were significantly protected from lethal challenge with wild-typeS.Enteritidis (80 to 100% vaccine efficacy).
The quality of websites addressing fibromyalgia: an assessment of quality and readability using standardised tools
Authors: Daraz Lubna , MacDermid Joy C , Wilkins Seanne , Gibson Jane , Shaw Lynn 
Published: August 2011

BackgroundPatients living with fibromyalgia strongly prefer to access health information on the web. However, the majority of subjects in previous studies strongly expressed their concerns about the quality of online information resources.ObjectivesThe purpose of this study was to evaluate existing online fibromyalgia information resources for content, quality and readability by using standardised quality and readability tools.MethodsThe first 25 websites were identified using Google and the search keyword ‘fibromyalgia’. Pairs of raters independently evaluated website quality using two structured tools (DISCERN and a quality checklist). Readability was assessed using the Flesch Reading Ease score maps.ResultsRanking of the websites' quality varied by the tool used, although there was general agreement about the top three websites (Fibromyalgia Information, Fibromyalgia Information Foundation and National Institute of Arthritis and Musculoskeletal and Skin Diseases). Content analysis indicated that 72% of websites provided information on treatment options, 68% on symptoms, 60% on diagnosis and 40% on coping and resources. DISCERN ratings classified 32% websites as ‘very good’, 32% as ‘good and 36% as ‘marginal’. The mean overall DISCERN score was 36.88 (good). Only 16% of websites met the recommended literacy level grade of 6–8 (range 7–15).ConclusionHigher quality websites tended to be less readable. Online fibromyalgia information resources do not provide comprehensive information about fibromyalgia, and have low quality and poor readability. While information is very important for those living with fibromyalgia, current resources are unlikely to provide necessary or accurate information, and may not be usable for most people.
Vitamin D3 Enhances the Apoptotic Response of Epithelial Tumors to Aminolevulinate-Based Photodynamic Therapy
Authors: Anand Sanjay , Wilson Clara , Hasan Tayyaba , Maytin Edward V. 
Published: August 2011

Abstract
Photodynamic therapy, mediated by exogenously administered aminolevulinic acid (ALA-PDT), followed by exposure to a laser or broadband light source, is a promising modality for treatment of many types of cancers; however, it remains inadequate to treat large, deep, solid tumors. In this article, we report that calcitriol, the active form of vitamin D3, can be administered before ALA as a nontoxic preconditioning regimen to markedly increase the efficacy of ALA-PDT. Using mouse models of squamous cell skin cancer for preclinical proof of concept, we showed that calcitriol, delivered topically or intraperitoneally, increased tumoral accumulation of the PDT-activated ALA product protoporphyrin-IX (PpIX) up to 10-fold, mainly by altering expression of the porphyrin-synthesis enzymes coproporphyrinogen oxidase (increased) and ferrochelatase (decreased). Calcitriol-pretreated tumors underwent enhanced apoptotic cell death after ALA-based PDT. Mechanistic studies have documented activation of the extrinsic apoptotic pathway, with specific cleavage of caspase-8 and increased production of TNF-α in tumors preconditioned by calcitriol treatment before receiving ALA-PDT. Very low doses of calcitriol (0.1–1 μg/kg body weight) were sufficient to elicit tumor-selective enhancement to ALA-PDT efficacy, rendering toxicity concerns negligible. Our findings define a simple, nontoxic, and highly effective preconditioning regimen to enhance the response of epithelial tumors to ALA-PDT, possibly broadening its clinical applications by selectively enhancing accumulation of photosensitizer PpIX together with TNF-α in tumors. Cancer Res; 71(18); 6040–50. ©2011 AACR.
KRAS and BRAF Mutation Analysis in Metastatic Colorectal Cancer: A Cost-effectiveness Analysis from a Swiss Perspective
Authors: Blank Patricia R. , Moch Holger , Szucs Thomas D. , Schwenkglenks Matthias 
Published: August 2011

Abstract
Purpose: Monoclonal antibodies against the epidermal growth factor receptor (EGFR), such as cetuximab, have led to significant clinical benefits for metastatic colorectal cancer (mCRC) patients but have also increased treatment costs considerably. Recent evidence associates KRAS and BRAF mutations with resistance to EGFR antibodies. We assessed the cost-effectiveness of predictive testing for KRAS and BRAF mutations, prior to cetuximab treatment of chemorefractory mCRC patients.
Experimental Design: A life-long Markov simulation model was used to estimate direct medical costs (€) and clinical effectiveness [quality-adjusted life-years (QALY)] of the following strategies: KRAS testing, KRAS testing with subsequent BRAF testing of KRAS wild-types (KRAS/BRAF), cetuximab treatment without testing. Comparison was against no cetuximab treatment (reference strategy). In the testing strategies, cetuximab treatment was initiated if no mutations were detected. Best supportive care was given to all patients. Survival times/utilities were derived from published randomized clinical trials. Costs were assessed from the perspective of the Swiss health system.
Results: Average remaining lifetime costs ranged from €3,983 (no cetuximab) to €38,662 (no testing). Cetuximab treatment guided by KRAS/BRAF achieved gains of 0.491 QALYs compared with the reference strategy. The KRAS testing strategy achieved an additional gain of 0.002 QALYs compared with KRAS/BRAF. KRAS/BRAF testing was the most cost-effective approach when compared with the reference strategy (incremental cost-effectiveness ratio: €62,653/QALY).
Conclusion: New predictive tests for KRAS and BRAF status are currently being introduced in pathology. Despite substantial costs of predictive testing, it is economically favorable to identify patients with KRAS and BRAF wild-type status. Clin Cancer Res; 17(19); 6338–46. ©2011 AACR.
Prognostic Impact of ΔTAp73 Isoform Levels and Their Target Genes in Colon Cancer Patients
Authors: Soldevilla Beatriz , Díaz Raquel , Silva Javier , Campos-Martín Yolanda , Muñoz Concepción , García Vanesa , García José M , Peña Cristina , Herrera Mercedes , Rodriguez Marta , Gómez Irene , Mohamed Nagat , Marques Margarita M. , Bonilla Félix , Domínguez Gemma 
Published: August 2011

Abstract
Purpose: Cumulative data support the role of ΔTAp73 variants in tumorigenic processes such as drug resistance. We evaluate the impact of TP73 isoforms and their putative target genes ABCB1, HMGB1, and CASP1 on the survival of colon cancer patients and the correlation between their expressions.
Experimental Design: We determined in 77 colon cancer patients the expression of ΔEx2p73, ΔEx2/3p73, ΔNp73, TAp73, ABCB1, HMGB1, and CASP1 by quantitative real-time reverse transcriptase-PCR. Tumor characteristics, disease-free survival, and overall survival (OS) were examined in each patient. Functional experiments were carried out to check whether ectopic expression of ΔNp73 modifies the proliferation, drug resistance, migration, and invasion properties of colon tumor cells and the expression of ABCB1, HMGB1, and CASP1.
Results: Positive correlations were observed between the expression levels of ΔTAp73 variants and HMGB1. Furthermore, a trend was observed for ABCB1. Overexpression of ΔEx2/3p73 and ΔNp73 isoforms was significantly associated with advanced stages (P = 0.04 and P = 0.03, respectively) and predicted shortened OS (P = 0.04 and P = 0.05, respectively). High levels of ABCB1 and HMGB1 were associated with shorter OS (P = 0.04 and P = 0.05, respectively). Multivariate analysis showed that, in addition to the tumor stage, ABCB1 and HMGB1 had independent relationships with OS (P = 0.008). Ectopic expression of ΔNp73 was associated with an increase in proliferation and drug resistance.
Conclusions: The positive correlation between ΔTAp73 variants and HMGB1 and ABCB1 expression supports them as TP73 targets. The fact that upregulation of ΔTAp73 isoforms was associated with shortened OS, increase in proliferation, and drug resistance confirms their oncogenic role and plausible value as prognostic markers. ABCB1 and HMGB1, putative ΔTAp73 target genes, strongly predict OS in an independent manner, making clear the importance of studying downstream TP73 targets that could predict the outcome of colon cancer patients better than ΔTAp73 variants themselves do. Clin Cancer Res; 17(18); 6029–39. ©2011 AACR.
Resection of Non–Small Cell Lung Cancers Reverses Tumor-Induced Gene Expression Changes in the Peripheral Immune System
Authors: Kossenkov Andrew V. , Vachani Anil , Chang Celia , Nichols Calen , Billouin Shere , Horng Wenhwai , Rom William N. , Albelda Steven M. , Showe Michael K. , Showe Louise C. 
Published: August 2011

Abstract
Purpose: To characterize the interactions of non–small cell lung cancer (NSCLC) tumors with the immune system at the level of mRNA and microRNA (miRNA) expression and to define expression signatures that characterize the presence of a malignant tumor versus a nonmalignant nodule.
Experimental Design: We have examined the changes of both mRNA and miRNA expression levels in peripheral blood mononuclear cells (PBMC) between paired samples collected from NSCLC patients before and after tumor removal using Illumina gene expression arrays.
Results: We found that malignant tumor removal significantly changes expression of more than 3,000 protein-coding genes, especially genes in pathways associated with suppression of the innate immune response, including natural killer cell signaling and apoptosis-associated ceramide signaling. Binding sites for the ETS domain transcription factors ELK1, ELK4, and SPI1 were enriched in promoter regions of genes upregulated in the presence of a tumor. Additional important regulators included five miRNAs expressed at significantly higher levels before tumor removal. Repressed protein-coding targets of those miRNAs included many transcription factors, several involved in immunologically important pathways. Although there was a significant overlap in the effects of malignant tumors and benign lung nodules on PBMC gene expression, we identified one gene panel which indicates a tumor or nodule presence and a second panel that can distinguish malignant from nonmalignant nodules.
Conclusions: A tumor presence in the lung influences mRNA and miRNA expression in PBMC and this influence is reversed by tumor removal. These results suggest that PBMC gene expression signatures could be used for lung cancer diagnosis. Clin Cancer Res; 17(18); 5867–77. ©2011 AACR.
Suppression of Autophagy by FIP200 Deletion Impairs DNA Damage Repair and Increases Cell Death upon Treatments with Anticancer Agents
Authors: Bae Heekyong , Guan Jun-Lin 
Published: August 2011

Abstract
Autophagy is a lysosomal bulk degradation process for intracellular protein and organelles. FIP200 (200 kDa FAK-family interacting protein) is an essential component of mammalian autophagy that is implicated in breast cancer in recent studies. Here we show that inactivation of FIP200 resulted in deficient repair of DNA damage induced by ionizing radiation and anticancer agents in mouse embryonic fibroblasts (MEF). The persistent DNA damage correlated to increased apoptosis and reduced survival of FIP200 knockout (KO) MEFs after treatments with camptothecin (CPT), a topoisomerase I inhibitor and chemotherapeutic agent. Reexpression of FIP200 in FIP200 KO MEFs restored both efficient DNA damage repair and cell survival. Furthermore, knockdown of the increased p62 expression in FIP200 KO MEFs rescued the impaired DNA damage repair and CPT-induced cell death. In contrast, treatment of cells with N-acetyl cysteine did not affect these defects in FIP200 KO MEFs. Finally, FIP200 KO MEFs also showed deficient DNA damage repair and increased cell death compared with control MEFs, when treated with etoposide, a topoisomerase II inhibitor and another anticancer agent. Together, these results identify a new function for FIP200 in the regulation of DNA damage response and cell survival through its activity in autophagy and suggest the possibility of FIP200 or other autophagy proteins as a potential target for treatment to enhance the efficiency of cancer therapy using DNA damage–inducing agents. Mol Cancer Res; 9(9); 1232–41. ©2011 AACR.