bluuebunny/crossref_metadata_2025_split huggingface dataset:
In vitro modelling of rat mucosal mast cell function in Trichinella spiralis infection
Authors: Thrasher S. M. , Scalfone L. K. , Holowka D. , Appleton J. A. 
Published: October 2012

SummaryIntestinal infection with the parasitic nematode, Trichinella spiralis, provides a robust context for the study of mucosal mast cell function. In rats, mucosal mast cells are exposed to parasites during the earliest stage of infection, affording an opportunity for mast cells to contribute to an innate response to infection. During secondary infection, degranulation of rat mucosal mast cells coincides with expulsion of challenge larvae from the intestine. The goal of this study was to evaluate the rat bone marrow‐derived mast cells (BMMC) and the rat basophilic leukaemia cell line (RBL‐2H3) as models for mucosal mast cells, using parasite glycoproteins and antibody reagents that have been tested extensively in rats in vivo. We found that BMMC displayed a more robust mucosal phenotype. Although T. spiralis glycoproteins bound to mast cell surfaces in the absence of antibodies, they did not stimulate degranulation, nor did they inhibit degranulation triggered by immune complexes. Parasite glycoproteins complexed with specific monoclonal IgGs provoked release of rat mast cell protease II (RMCPII) and β‐hexosaminidase from both cell types in a manner that replicated results observed previously in passively immunized rats. Our results document that RBL‐2H3 cells and BMMC model rat mucosal mast cells in the contexts of innate and adaptive responses to T. spiralis.
Comparison of Procedure Cost for Thrombectomy of Arteriovenous Fistulas and Grafts
Authors: Schon Donald , DeLozier Tammy , Patel Nina 
Published: October 2012

AbstractExpenditures on dialysis vascular access now exceed $2.5 Billion annually in the US. Studies suggest that significant savings could be achieved by increasing arteriovenous fistula (AVF) prevalence to >65%. It is common but unsubstantiated opinion that AVF have lower maintenance costs than arteriovenous grafts (AVG). This manuscript tests this hypothesis by direct comparison. Equipment utilization time and supply utilization on 110 thrombectomy procedures on AVF and 258 on AVG were compared. Procedures techniques were standardized within one facility and procedures performed by a multiple but limited number of operators. There were no significant differences in demographic variables and comorbid factors between groups. Time to complete AVF thrombectomy was 1.7 times that for AVG. In addition, major supplies used such as wires and balloons were also significantly greater. Interventionists who took longer than average to thrombectomize AVF took longer than average to thrombectomize AVG. The prevalence of arterial inflow lesions was 1.5 greater in thrombosed AVF versus Thrombosed AVG. Procedure costs when analyzed in terms of procedure time, room utilization, staff, and equipment are significantly greater for thrombosed AVF than thrombosed AVG.
Serological survey of HIV and syphilis in pregnant women in Madagascar
Authors: Frickmann Hagen , Schwarz Norbert G. , Girmann Mirko , Hagen Ralf M. , Poppert Sven , Crusius Sabine , Podbielski Andreas , Heriniaina Jean N. , Razafindrabe Tsiriniaina , Rakotondrainiarivelo Jean P. , May Jürgen , Rakotozandrindrainy Raphaël 
Published: October 2012

AbstractObjectives  Peripartal transmission of human immunodeficiency virus (HIV) and Treponema pallidum, the causative agent of syphilis, leads to severe consequences for newborns. Preventive measures require awareness of the maternal infection. Although HIV and syphilis testing in Madagascar could be theoretically carried out within the framework of the national pregnancy follow‐up scheme, the required test kits are rarely available at peripheral health centres. In this study, we screened blood samples of pregnant Madagascan women for HIV and syphilis seroprevalence to estimate the demand for systemic screening in pregnancy.Methods  Retrospective anonymous serological analysis for HIV and syphilis was performed in plasma samples from 1232 pregnant women that were taken between May and July 2010 in Ambositra, Ifanadiana, Manakara, Mananjary, Moramanga and Tsiroanomandidy (Madagascar) during pregnancy follow‐up. Screening was based on Treponema pallidum haemagglutination tests for syphilis and rapid tests for HIV, with confirmation of positive screening results on line assays.Results  Out of 1232 pregnant women, none were seropositive for HIV and 37 (3%) were seropositive for Treponema pallidum.Conclusions  Our findings are in line with previous studies that describe considerable syphilis prevalence in the rural Madagascan population. The results suggest a need for screening to prevent peripartal Treponema pallidum transmission, while HIV is still rare. If they are known, Treponema pallidum infections can be easily, safely and inexpensively treated even in pregnancy to reduce the risk of transmission.
High β-Lactamase Levels Change the Pharmacodynamics of β-Lactam Antibiotics in Pseudomonas aeruginosa Biofilms
Authors: Hengzhuang Wang , Ciofu Oana , Yang Liang , Wu Hong , Song Zhijun , Oliver Antonio , Høiby Niels 
Published: October 2012

ABSTRACT

Resistance to β-lactam antibiotics is a frequent problem in
Pseudomonas aeruginosa
lung infection of cystic fibrosis (CF) patients. This resistance is mainly due to the hyperproduction of chromosomally encoded β-lactamase and biofilm formation. The purpose of this study was to investigate the role of β-lactamase in the pharmacokinetics (PK) and pharmacodynamics (PD) of ceftazidime and imipenem on
P. aeruginosa
biofilms.
P. aeruginosa
PAO1 and its corresponding β-lactamase-overproducing mutant, PAΔDDh2Dh3, were used in this study. Biofilms of these two strains in flow chambers, microtiter plates, and on alginate beads were treated with different concentrations of ceftazidime and imipenem. The kinetics of antibiotics on the biofilms was investigated
in vitro
by time-kill methods. Time-dependent killing of ceftazidime was observed in PAO1 biofilms, but concentration-dependent killing activity of ceftazidime was observed for β-lactamase-overproducing biofilms of
P. aeruginosa
in all three models. Ceftazidime showed time-dependent killing on planktonic PAO1 and PAΔDDh2Dh3. This difference is probably due to the special distribution and accumulation in the biofilm matrix of β-lactamase, which can hydrolyze the β-lactam antibiotics. The PK/PD indices of the AUC/MBIC and
C
max
/MBIC (AUC is the area under concentration-time curve, MBIC is the minimal biofilm-inhibitory concentration, and
C
max
is the maximum concentration of drug in serum) are probably the best parameters to describe the effect of ceftazidime in β-lactamase-overproducing
P. aeruginosa
biofilms. Meanwhile, imipenem showed time-dependent killing on both PAO1 and PAΔDDh2Dh3 biofilms. An inoculum effect of β-lactams was found for both planktonic and biofilm
P. aeruginosa
cells. The inoculum effect of ceftazidime for the β-lactamase-overproducing mutant PAΔDDh2Dh3 biofilms was more obvious than for PAO1 biofilms, with a requirement of higher antibiotic concentration and a longer period of treatment.
Inhibition of Chikungunya Virus Replication by Harringtonine, a Novel Antiviral That Suppresses Viral Protein Expression
Authors: Kaur Parveen , Thiruchelvan Meerra , Lee Regina Ching Hua , Chen Huixin , Chen Karen Caiyun , Ng Mah Lee , Chu Justin Jang Hann 
Published: October 2012

ABSTRACT

Chikungunya virus (CHIKV) is a mosquito-transmitted virus that has reemerged as a significant public health threat in the last decade. Since the 2005-2006 chikungunya fever epidemic in the Indian Ocean island of La Réunion, millions of people in more than 40 countries have been infected. Despite this, there is currently no antiviral treatment for chikungunya infection. In this study, an immunofluorescence-based screening platform was developed to identify potential inhibitors of CHIKV infection. A primary screen was performed using a highly purified natural product compound library, and 44 compounds exhibiting ≥70% inhibition of CHIKV infection were identified as positive hits. Among these, four were selected for dose-dependent inhibition assays to confirm their anti-CHIKV activity. Harringtonine, a cephalotaxine alkaloid, displayed potent inhibition of CHIKV infection (50% effective concentration [EC
50
] = 0.24 μM) with minimal cytotoxicity and was selected for elucidation of its antiviral mechanism. Time-of-addition studies, cotreatment assays, and direct transfection of viral genomic RNA indicated that harringtonine inhibited an early stage of the CHIKV replication cycle which occurred after viral entry into cells. In addition, quantitative reverse transcription-PCR (qRT-PCR) and Western blot analyses indicated that harringtonine affects CHIKV RNA production as well as viral protein expression. Treatment of harringtonine against Sindbis virus, a related alphavirus, suggested that harringtonine could inhibit other alphaviruses. This study suggests for the first time that harringtonine exerts its antiviral effects by inhibiting CHIKV viral protein synthesis.
Increased Survival of Antibiotic-Resistant Escherichia coli inside Macrophages
Authors: Miskinyte Migla , Gordo Isabel 
Published: October 2012

ABSTRACT

Mutations causing antibiotic resistance usually incur a fitness cost in the absence of antibiotics. The magnitude of such costs is known to vary with the environment. Little is known about the fitness effects of antibiotic resistance mutations when bacteria confront the host's immune system. Here, we study the fitness effects of mutations in the
rpoB
,
rpsL
, and
gyrA
genes, which confer resistance to rifampin, streptomycin, and nalidixic acid, respectively. These antibiotics are frequently used in the treatment of bacterial infections. We measured two important fitness traits—growth rate and survival ability—of 12
Escherichia coli
K-12 strains, each carrying a single resistance mutation, in the presence of macrophages. Strikingly, we found that 67% of the mutants survived better than the susceptible bacteria in the intracellular niche of the phagocytic cells. In particular, all
E. coli
streptomycin-resistant mutants exhibited an intracellular advantage. On the other hand, 42% of the mutants incurred a high fitness cost when the bacteria were allowed to divide outside of macrophages. This study shows that single nonsynonymous changes affecting fundamental processes in the cell can contribute to prolonged survival of
E. coli
in the context of an infection.
In Vitro
Activity of Daclatasvir on Hepatitis C Virus Genotype 3 NS5A
Authors: Wang Chunfu , Valera Lourdes , Jia Lingling , Kirk Melissa J. , Gao Min , Fridell Robert A. 
Published: October 2012

ABSTRACT

The NS5A replication complex inhibitor daclatasvir (DCV; BMS-790052) inhibits hybrid replicons containing hepatitis C virus (HCV) genotype 3a (HCV3a) NS5A genes with 50% effective concentrations (EC
50
s) ranging from 120 to 870 pM. Selection studies with a hybrid HCV3a replicon identified NS5A residues 31 and 93 as sites for DCV-selected resistance. Our results support the potential use of DCV as a component in combination therapies for HCV3a chronic infection.
Cytotoxic Necrotizing Factor 1 and Hemolysin from Uropathogenic Escherichia coli Elicit Different Host Responses in the Murine Bladder
Authors: Garcia Tamako A. , Ventura Christy L. , Smith Mark A. , Merrell D. Scott , O'Brien Alison D. 
Published: October 2012

ABSTRACTCytotoxic necrotizing factor 1 (CNF1) and hemolysin (HlyA1) are toxins produced by uropathogenicEscherichia coli(UPEC). We previously showed that these toxins contribute to the inflammation and tissue damage seen in a mouse model of ascending urinary tract infection. CNF1 constitutively activates small Rho GTPases by deamidation of a conserved glutamine residue, and HlyA1 forms pores in eukaryotic cell membranes. In this study, we used cDNA microarrays of bladder tissue isolated from mice infected intraurethrally with wild-type CP9, CP9cnf1, or CP9ΔhlyAto further evaluate the role that each toxin plays in the host response to UPEC. Regardless of the strain used, we found that UPEC itself elicited a significant change in host gene expression 24 h after inoculation. The largest numbers of upregulated genes were in the cytokine and chemokine signaling and Toll-like receptor signaling pathways. CNF1 exerted a strong positive influence on expression of genes involved in innate immunity and signal transduction and a negative impact on metabolism- and transport-associated genes. HlyA1 evoked an increase in expression of genes that encode innate immunity factors and a decrease in expression of genes involved in cytoskeletal and metabolic processes. Multiplex cytokine and myeloperoxidase assays corroborated our finding that a strong proinflammatory response was elicited by all strains tested. Bladders challenged intraurethrally with purified CNF1 displayed pathology similar to but significantly less intense than the pathology that we observed in CP9-challenged mice. Our data demonstrate substantial roles for CNF1 and HlyA1 in initiation of a strong proinflammatory response to UPEC in the bladder.
Role of YopK in Yersinia pseudotuberculosis Resistance against Polymorphonuclear Leukocyte Defense
Authors: Thorslund Sara E. , Ermert David , Fahlgren Anna , Erttmann Saskia F. , Nilsson Kristina , Hosseinzadeh Ava , Urban Constantin F. , Fällman Maria 
Published: October 2012

ABSTRACTThe enteropathogenYersinia pseudotuberculosiscan survive in the harsh environment of lymphoid compartments that abounds in immune cells. This capacity is dependent on the plasmid-encodedYersiniaouter proteins (Yops) that are delivered into the host cell via a mechanism involving theYersiniatype III secretion system. We show that the virulence protein YopK has a role in the mechanism by whichY. pseudotuberculosisavoids the polymorphonuclear leukocyte or neutrophil (PMN) defense. AyopKmutant, which is attenuated in the mouse infection model, where it fails to cause systemic infection, was found to colonize Peyer's patches and mesenteric lymph nodes more rapidly than the wild-type strain. Further, in mice lacking PMNs, theyopKmutant caused full disease with systemic spread and typical symptoms. Analyses of effects on PMNs revealed that both the wild-type strain and theyopKmutant inhibited internalization and reactive oxygen species production, as well as neutrophil extracellular trap formation by PMNs. However, the wild-type strain effectively avoided induction of PMN death, whereas the mutant caused a necrosis-like PMN death. Taken together, our results indicate that YopK is required for the ability ofYersiniato resist the PMN defense, which is critical for the virulence of the pathogen. We suggest a mechanism whereby YopK functions to prevent unintended Yop delivery and thereby PMN disruption, resulting in necrosis-like cell death, which would enhance the inflammatory response favoring the host.
Inactivation of Epidermal Growth Factor by Porphyromonas gingivalis as a Potential Mechanism for Periodontal Tissue Damage
Authors: Pyrc Krzysztof , Milewska Aleksandra , Kantyka Tomasz , Sroka Aneta , Maresz Katarzyna , Kozieł Joanna , Nguyen Ky-Anh , Enghild Jan J. , Knudsen Anders Dahl , Potempa Jan 
Published: October 2012

ABSTRACT

Porphyromonas gingivalis
is a Gram-negative bacterium associated with the development of periodontitis. The evolutionary success of this pathogen results directly from the presence of numerous virulence factors, including peptidylarginine deiminase (PPAD), an enzyme that converts arginine to citrulline in proteins and peptides. Such posttranslational modification is thought to affect the function of many different signaling molecules. Taking into account the importance of tissue remodeling and repair mechanisms for periodontal homeostasis, which are orchestrated by ligands of the epidermal growth factor receptor (EGFR), we investigated the ability of PPAD to distort cross talk between the epithelium and the epidermal growth factor (EGF) signaling pathway. We found that EGF preincubation with purified recombinant PPAD, or a wild-type strain of
P. gingivalis
, but not with a PPAD-deficient isogenic mutant, efficiently hindered the ability of the growth factor to stimulate epidermal cell proliferation and migration. In addition, PPAD abrogated EGFR-EGF interaction-dependent stimulation of expression of suppressor of cytokine signaling 3 and interferon regulatory factor 1. Biochemical analysis clearly showed that the PPAD-exerted effects on EGF activities were solely due to deimination of the C-terminal arginine. Interestingly, citrullination of two internal Arg residues with human endogenous peptidylarginine deiminases did not alter EFG function, arguing that the C-terminal arginine is essential for EGF biological activity. Cumulatively, these data suggest that the PPAD-activity-abrogating EGF function in gingival pockets may at least partially contribute to tissue damage and delayed healing within
P. gingivalis
-infected periodontia.
Vitamin D and the Human Antimicrobial Peptide LL-37 Enhance Group AStreptococcusResistance to Killing by Human Cells
Authors: Love John F. , Tran-Winkler Hien J. , Wessels Michael R. 
Published: October 2012

ABSTRACTThe CsrRS two-component regulatory system of group AStreptococcus(GAS;Streptococcus pyogenes) responds to subinhibitory concentrations of the human antimicrobial peptide LL-37. LL-37 signaling through CsrRS results in upregulation of genes that direct synthesis of virulence factors, including the hyaluronic acid capsule and streptolysin O (SLO). Here, we demonstrate that a consequence of this response is augmented GAS resistance to killing by human oropharyngeal keratinocytes, neutrophils, and macrophages. LL-37-induced upregulation of SLO and hyaluronic acid capsule significantly reduced internalization of GAS by keratinocytes and phagocytic killing by neutrophils and macrophages. Because vitamin D induces LL-37 production by macrophages, we tested its effect on macrophage killing of GAS. In contrast to the reported enhancement of macrophage function in relation to other pathogens, treatment of macrophages with 1α,25-dihydroxy-vitamin D3 paradoxically reduced the ability of macrophages to control GAS infection. These observations demonstrate that LL-37 signals through CsrRS to induce a virulence phenotype in GAS characterized by heightened resistance to ingestion and killing by both epithelial cells and phagocytes. By inducing LL-37 production in macrophages, vitamin D may contribute to this paradoxical exacerbation of GAS infection.IMPORTANCEIt remains poorly understood why group AStreptococcus(GAS) causes asymptomatic colonization or localized throat inflammation in most individuals but rarely progresses to invasive infection. The human antimicrobial peptide LL-37, which is produced as part of the innate immune response to GAS infection, signals through the GAS CsrRS two-component regulatory system to upregulate expression of multiple virulence factors. This study reports that two CsrRS-regulated GAS virulence factors—streptolysin O and the hyaluronic acid capsule—are critical in LL-37-induced resistance of GAS to killing by human throat epithelial cells and by neutrophils and macrophages. Vitamin D, which increases LL-37 production in macrophages, has the paradoxical effect of increasing GAS resistance to macrophage-mediated killing. In this way, the human innate immune response may promote the transition from GAS colonization to invasive infection.
Assessing the effect of regional deprivation on mortality avoiding compositional bias: a natural experiment
Authors: Reiss Katharina , Berger Ursula , Winkler Volker , Voigtländer Sven , Becher Heiko , Razum Oliver 
Published: October 2012

Background and objectiveWe assessed the effect of regional deprivation on individual mortality by making use of a natural experiment: we followed up ethnic German resettlers from Former Soviet Union countries who were quasi-randomly distributed across the socioeconomically heterogeneous counties of Germany's federal state North Rhine-Westphalia (NRW).MethodsWe used data from the retrospective cohort study ‘AMOR’ on the mortality of resettlers in NRW (n=34 393). Based on the postcode of the last known residence we linked study participants to the 54 counties of NRW, which were aggregated in six deprivation clusters. Mortality rates and standardised mortality ratios (SMRs) were calculated for each cluster. After a mean follow-up of 10 years, 2580 resettlers were deceased.ResultsFor male and female cohort members, mortality rates and SMRs were highest in the cluster ‘poverty poles’ (SMR men: 1.21, 95% CI 1.04 to 1.41; SMR women: 1.17, 95% CI 0.99 to 1.37), whereas they were lowest in the cluster ‘prospering regions and suburban counties’ (SMR women: 0.86, 95% CI 0.70 to 1.05) as well as in the cluster ‘heterogeneous counties’ (SMR men: 0.73, 95% CI 0.61 to 0.88).ConclusionsThe population which was quasi-randomly distributed to counties of differing socioeconomic status experienced different levels of mortality. It was highest in regions with the highest level of regional deprivation. Previous studies describing this positive relationship between mortality and regional deprivation could not differentiate between compositional and contextual effects. Thus, our findings indicate that in terms of mortality, regional deprivation does matter.
Comparison of self-obtained penile-meatal swabs to urine for the detection ofC. trachomatis,N. gonorrhoeaeandT. vaginalis
Authors: Dize Laura , Agreda Patricia , Quinn Nicole , Barnes Mathilda R , Hsieh Yu-Hsiang , Gaydos Charlotte A 
Published: October 2012

BackgroundSelf-obtained penile-meatal swabs and urine specimens have been used forChlamydia trachomatis(CT),Neisseria gonorrhoeae(NG) andTrichomonas vaginalis(TV) for outreach screening in men.ObjectiveTo compare the sensitivity of self-collected male penile-meatal swabs and urine for the detection ofCT,NGandTV.MethodsMatching penile-meatal swabs and urines were collected at home after recruitment to the study; via the internet programme,http://www.iwantthekit.org. The instructions directed the participant to place the tip of a Copan flocked swab at the meatal opening of the urethra to collect the penile-meatal sample. Two ml of urine was collected after the swab onto a Copan sponge-on-a-shaft collection device. Both swab and urine were placed into individual Aptima transport media tubes and mailed to the laboratory for testing. All specimens were tested for CT and NG using the GenProbe Aptima Combo2 Assay and for TV using GenProbe Aptima Analyte Specific Reagents with TV oligonucleotides.ResultsOf 634 men, 86 (13.6%) were positive for CT, 9 (1.4%) were positive for NG and 56 (9.3%) positive for TV. For CT, swab sensitivity was 81/86 (94.2%), and urine sensitivity was 66/86 (76.7%). For NG, swab sensitivity was 9/9 (100%) and urine sensitivity was 8/9 (88.9%). For TV, swab sensitivity was 45/56 (80.4%) and urine sensitivity was 22/56 (39.3%).ConclusionsSelf-obtained penile-meatal swabs provided for the detection of more CT, NG and TV, than urine specimens.