bluuebunny/crossref_metadata_2025_split huggingface dataset:
Antigenic Characterization of an Intrinsically Unstructured Protein, Plasmodium falciparum Merozoite Surface Protein 2
Authors: Adda Christopher G. , MacRaild Christopher A. , Reiling Linda , Wycherley Kaye , Boyle Michelle J. , Kienzle Vivian , Masendycz Paul , Foley Michael , Beeson James G. , Norton Raymond S. , Anders Robin F. 
Published: September 2012

ABSTRACTMerozoite surface protein 2 (MSP2) is an abundant glycosylphosphatidylinositol (GPI)-anchored protein ofPlasmodium falciparum, which is a potential component of a malaria vaccine. As all forms of MSP2 can be categorized into two allelic families, a vaccine containing two representative forms of MSP2 may overcome the problem of diversity in this highly polymorphic protein. Monomeric recombinant MSP2 is an intrinsically unstructured protein, but its conformational properties on the merozoite surface are unknown. This question is addressed here by analyzing the 3D7 and FC27 forms of recombinant and parasite MSP2 using a panel of monoclonal antibodies raised against recombinant MSP2. The epitopes of all antibodies, mapped using both a peptide array and by nuclear magnetic resonance (NMR) spectroscopy on full-length recombinant MSP2, were shown to be linear. The antibodies revealed antigenic differences, which indicate that the conserved N- and C-terminal regions, but not the central variable region, are less accessible in the parasite antigen. This appears to be an intrinsic property of parasite MSP2 and is not dependent on interactions with other merozoite surface proteins as the loss of some conserved-region epitopes seen using the immunofluorescence assay (IFA) on parasite smears was also seen on Western blot analyses of parasite lysates. Further studies of the structural basis of these antigenic differences are required in order to optimize recombinant MSP2 constructs being evaluated as potential vaccine components.
The Hydroxamate Siderophore Rhequichelin Is Required for Virulence of the Pathogenic Actinomycete Rhodococcus equi
Authors: Miranda-CasoLuengo Raúl , Coulson Garry B. , Miranda-CasoLuengo Aleksandra , Vázquez-Boland José A. , Hondalus Mary K. , Meijer Wim G. 
Published: September 2012

ABSTRACT

We previously showed that the facultative intracellular pathogen
Rhodococcus equi
produces a nondiffusible and catecholate-containing siderophore (rhequibactin) involved in iron acquisition during saprophytic growth. Here, we provide evidence that the
rhbABCDE
cluster directs the biosynthesis of a hydroxamate siderophore, rhequichelin, that plays a key role in virulence. The
rhbC
gene encodes a nonribosomal peptide synthetase that is predicted to produce a tetrapeptide consisting of
N

5

-formyl-
N
5
-hydroxyornithine, serine,
N
5
-hydroxyornithine, and
N

5

-acyl-
N
5
-hydroxyornithine. The other
rhb
genes encode putative tailoring enzymes mediating modification of ornithine residues incorporated into the hydroxamate product of RhbC. Transcription of
rhbC
was upregulated during growth in iron-depleted medium, suggesting that it plays a role in iron acquisition. This was confirmed by deletion of
rhbCD
, rendering the resulting strain
R. equi
SID2 unable to grow in the presence of the iron chelator 2,2-dipyridyl. Supernatant of the wild-type strain rescued the phenotype of
R. equi
SID2. The importance of rhequichelin in virulence was highlighted by the rapid increase in transcription levels of
rhbC
following infection and the inability of
R. equi
SID2 to grow within macrophages. Unlike the wild-type strain,
R. equi
SID2 was unable to replicate
in vivo
and was rapidly cleared from the lungs of infected mice. Rhequichelin is thus a key virulence-associated factor, although nonpathogenic
Rhodococcus
species also appear to produce rhequichelin or a structurally closely related compound. Rhequichelin biosynthesis may therefore be considered an example of cooption of a core actinobacterial trait in the evolution of
R. equi
virulence.
Escherichia coli Isolates That Carry
vat
,
fyuA
,
chuA
, and
yfcV
Efficiently Colonize the Urinary Tract
Authors: Spurbeck Rachel R. , Dinh Paul C. , Walk Seth T. , Stapleton Ann E. , Hooton Thomas M. , Nolan Lisa K. , Kim Kwang Sik , Johnson James R. , Mobley Harry L. T. 
Published: September 2012

ABSTRACT

Extraintestinal
Escherichia coli
(ExPEC), a heterogeneous group of pathogens, encompasses avian, neonatal meningitis, and uropathogenic
E. coli
strains. While several virulence factors are associated with ExPEC, there is no core set of virulence factors that can be used to definitively differentiate these pathotypes. Here we describe a multiplex of four virulence factor-encoding genes,
yfcV
,
vat
,
fyuA
, and
chuA
, highly associated with uropathogenic
E. coli
strains that can distinguish three groups of
E. coli
: diarrheagenic and animal-associated
E. coli
strains, human commensal and avian pathogenic
E. coli
strains, and uropathogenic and neonatal meningitis
E. coli
strains. Furthermore, human intestinal isolates that encode all four predictor genes express them during exponential growth in human urine and colonize the bladder in the mouse model of ascending urinary tract infection in higher numbers than human commensal strains that do not encode the four predictor genes (
P
= 0.02), suggesting that the presence of the predictors correlates with uropathogenic potential.
Leptospiral Outer Membrane Protein Microarray, a Novel Approach to Identification of Host Ligand-Binding Proteins
Authors: Pinne Marija , Matsunaga James , Haake David A. 
Published: September 2012

ABSTRACTLeptospirosis is a zoonosis with worldwide distribution caused by pathogenic spirochetes belonging to the genusLeptospira. The leptospiral life cycle involves transmission via freshwater and colonization of the renal tubules of their reservoir hosts. Infection requires adherence to cell surfaces and extracellular matrix components of host tissues. These host-pathogen interactions involve outer membrane proteins (OMPs) expressed on the bacterial surface. In this study, we developed anLeptospira interrogansserovar Copenhageni strain Fiocruz L1-130 OMP microarray containing all predicted lipoproteins and transmembrane OMPs. A total of 401 leptospiral genes or their fragments were transcribed and translatedin vitroand printed on nitrocellulose-coated glass slides. We investigated the potential of this protein microarray to screen for interactions between leptospiral OMPs and fibronectin (Fn). This approach resulted in the identification of the recently described fibronectin-binding protein, LIC10258 (MFn8, Lsa66), and 14 novel Fn-binding proteins, denotedMicroarrayFn-binding proteins (MFns). We confirmed Fn binding of purified recombinant LIC11612 (MFn1), LIC10714 (MFn2), LIC11051 (MFn6), LIC11436 (MFn7), LIC10258 (MFn8, Lsa66), and LIC10537 (MFn9) by far-Western blot assays. Moreover, we obtained specific antibodies to MFn1, MFn7, MFn8 (Lsa66), and MFn9 and demonstrated that MFn1, MFn7, and MFn9 are expressed and surface exposed underin vitrogrowth conditions. Further, we demonstrated that MFn1, MFn4 (LIC12631, Sph2), and MFn7 enable leptospires to bind fibronectin when expressed in the saprophyte,Leptospira biflexa. Protein microarrays are valuable tools for high-throughput identification of novel host ligand-binding proteins that have the potential to play key roles in the virulence mechanisms of pathogens.
Directional Evolution of Chlamydia trachomatis towards Niche-Specific Adaptation
Authors: Borges Vítor , Nunes Alexandra , Ferreira Rita , Borrego Maria J. , Gomes João P. 
Published: September 2012

ABSTRACT

On behalf of the host-pathogen “arms race,” a cutting-edge approach for elucidating genotype-phenotype relationships relies on the identification of positively selected loci involved in pathoadaptation. We studied the obligate intracellular bacterium
Chlamydia trachomatis
, for which same-species strains display a nearly identical core and pan genome, while presenting a wide range of tissue tropism and ecological success. We sought to evaluate the evolutionary patterns underlying species separation (divergence) and
C. trachomatis
serovar radiation (polymorphism) and to establish genotype-phenotype associations. By analyzing 60
Chlamydia
strains, we detected traces of Muller's ratchet as a result of speciation and identified positively selected genes and codons hypothetically involved in the infection of different human cell types (e.g., columnar epithelial cells of ocular or genital mucosae and mononuclear phagocytes) and also events likely driving pathogenic and ecological success dissimilarities. In general, these genes code for proteins involved in immune response elicitation, proteolysis, and the subversion of host-cell functions, and also for proteins with unknown function(s). Several genes are potentially involved in more than one adaptive process, suggesting multiple functions or a distinct
modus operandi
for a specific function, and thus should be considered as crucial research targets. In addition, six of the nine genes encoding the putative antigen/adhesin polymorphic membrane proteins seem to be under positive selection along specific serovars, which sustains an essential biological role of this extra-large paralogue family in chlamydial pathobiology. This study provides insight into how evolutionary inferences illuminate ecological processes such as adaptation to different niches, pathogenicity, or ecological success driven by arms races.
A Conserved UDP-Glucose Dehydrogenase Encoded outside the
hasABC
Operon Contributes to Capsule Biogenesis in Group A Streptococcus
Authors: Cole Jason N. , Aziz Ramy K. , Kuipers Kirsten , Timmer Anjuli M. , Nizet Victor , van Sorge Nina M. 
Published: September 2012

ABSTRACT

Group A
Streptococcus
(GAS) is a human-specific bacterial pathogen responsible for serious morbidity and mortality worldwide. The hyaluronic acid (HA) capsule of GAS is a major virulence factor, contributing to bloodstream survival through resistance to neutrophil and antimicrobial peptide killing and to
in vivo
pathogenicity. Capsule biosynthesis has been exclusively attributed to the ubiquitous
hasABC
hyaluronan synthase operon, which is highly conserved across GAS serotypes. Previous reports indicate that
hasA
, encoding hyaluronan synthase, and
hasB
, encoding UDP-glucose 6-dehydrogenase, are essential for capsule production in GAS. Here, we report that precise allelic exchange mutagenesis of
hasB
in GAS strain 5448, a representative of the globally disseminated M1T1 serotype, did not abolish HA capsule synthesis.
In silico
whole-genome screening identified a putative HasB paralog, designated HasB2, with 45% amino acid identity to HasB at a distant location in the GAS chromosome.
In vitro
enzymatic assays demonstrated that recombinant HasB2 is a functional UDP-glucose 6-dehydrogenase enzyme. Mutagenesis of
hasB2
alone slightly decreased capsule abundance; however, a Δ
hasB
Δ
hasB2
double mutant became completely acapsular. We conclude that HasB is not essential for M1T1 GAS capsule biogenesis due to the presence of a newly identified HasB paralog, HasB2, which most likely resulted from gene duplication. The identification of redundant UDP-glucose 6-dehydrogenases underscores the importance of HA capsule expression for M1T1 GAS pathogenicity and survival in the human host.
Analysis of ThiC Variants in the Context of the Metabolic Network of Salmonella enterica
Authors: Palmer Lauren D. , Dougherty Michael J. , Downs Diana M. 
Published: September 2012

ABSTRACT

In bacteria, the 4-amino-hydroxymethyl-2-methylpyrimidine (HMP) moiety of thiamine is synthesized from 5-aminoimidazole ribotide (AIR), a branch point metabolite of purine and thiamine biosynthesis. ThiC is a member of the radical
S
-adenosylmethionine (AdoMet) superfamily and catalyzes the complex chemical rearrangement of AIR to HMP-P. As reconstituted
in vitro
, the ThiC reaction requires AdoMet, AIR, and reductant. This study analyzed variants of ThiC
in vivo
and
in vitro
to probe the metabolic network surrounding AIR in
Salmonella enterica
. Several variants of ThiC that required metabolic perturbations to function
in vivo
were biochemically characterized
in vitro
. Results presented herein indicate that the subtleties of the metabolic network have not been captured in the current reconstitution of the ThiC reaction.
The Combined Effect of Acupuncture and Tanacetum parthenium on quality of life in women with headache: Randomised study
Authors: Ferro Eliane Cristina , Biagini Angelo Piva , da Silva Ícaro Eduardo Fuchs , Silva Marcelo Lourenço , Silva Josie Resende Torres 
Published: September 2012

Background The aim of the present study was to investigate the efficacy and tolerability of acupuncture (AC), Tanacetum (TAN) or combined treatment on quality of life in women with chronic migraine (CM). Methods A total of 69 women volunteers were randomly divided into 3 groups: AC, acupuncture administered in 20 sessions over 10 weeks (n=22); TAN, at 150 mg/day (n=23); and AC+TAN (n=23). The primary outcome was Short-Form 36 (SF-36) quality of life assessment score. Secondary outcomes included the Migraine Disability Assessment (MIDAS) and visual analogue scale (VAS) score experienced after randomisation. Results AC+TAN was statistically significantly more effective than AC or TAN alone in overall health-related quality of life (SF-36; p<0.05), on MIDAS score (−35.1 (10.6) AC vs −24.8 (11.7) TAN vs −42.5 (9.8) AC+TAN; p<0.05) and in reducing the mean score of pain on VAS (−5.6 (2.4) AC vs −3.7 (2.1) TAN vs −6.4 (3.1) AC+TAN; p<0.05). Conclusions The present work shows an improvement of the quality of life and better analgesic effect of acupuncture combined with TAN treatment on migraine pain in women when compared with acupuncture or TAN alone.
Epilepsies in infancy
Authors: Alam Shouja , Lux Andrew L 
Published: September 2012

To evaluate and manage epileptic seizures and other paroxysmal events in infants, it is necessary to ask five key questions: (1) Is this a type of epilepsy?; (2) What seizure type(s) are occurring?; (3) Do these seizure types, combined with factors such as age at onset and EEG features, constitute an ‘epilepsy syndrome’?; (4) What investigations do we need to do in searching for an underlying aetiology? and finally, (5) What is the prognosis for neurological and developmental state in later life?This review considers epilepsies that have an onset in infancy but after the perinatal period, outlines the commoner epilepsy syndromes occurring in this age group and describes paroxysmal events that can mimic epilepsy. Epilepsies in infancy may be the manifestation of a genetic predisposition associated with a benign course and good prognosis for neurodevelopment. In contrast, they may pose the challenging situation of ‘epileptic encephalopathy’, rare but potentially treatable metabolic conditions, or structural abnormalities with poor developmental outlook and intractable seizures. Seizures in infancy are relatively rare and there is a wide range of underlying causes, some of which require specific treatments to avoid preventable neurodevelopmental damage. Guidance from the National Institute for Health and Clinical Excellence suggests early referral of cases of infantile epilepsy to a tertiary centre.
Are boys and girls that different? An analysis of traumatic brain injury in children
Authors: Collins Niamh C , Molcho Michal , Carney Peter , McEvoy Linda , Geoghegan Lourda , Phillips Jack P , Nicholson Alf J 
Published: September 2012

IntroductionThe Phillips Report on traumatic brain injury (TBI) in Ireland found that injury was more frequent in men and that gender differences were present in childhood. This study determined when gender differences emerge and examined the effect of gender on the mechanism of injury, injury type and severity and outcome.MethodsA national prospective, observational study was conducted over a 2-year period. All patients under 17 years of age referred to a neurosurgical service following TBI were included. Data on patient demographics, events surrounding injury, injury type and severity, patient management and outcome were collected from ‘on-call’ logbooks and neurosurgical admissions records.Results342 patients were included. Falls were the leading cause of injury for both sexes. Boys’ injuries tended to involve greater energy transfer and involved more risk-prone behaviour resulting in a higher rate of other (non-brain) injury and a higher mortality rate. Intentional injury occurred only in boys. While injury severity was similar for boys and girls, significant gender differences in injury type were present; extradural haematomas were significantly higher in boys (p=0.014) and subdural haematomas were significantly higher in girls (p=0.011). Mortality was 1.8% for girls and 4.3% for boys.ConclusionsFalls were responsible for most TBI, the home is the most common place of injury and non-operable TBI was common. These findings relate to all children. Significant gender differences exist from infancy. Boys sustained injuries associated with a greater energy transfer, were less likely to use protective devices and more likely to be injured deliberately. This results in a different pattern of injury, higher levels of associated injury and a higher mortality rate.
Deliberate self-harm patients in the emergency department: who will repeat and who will not? Validation and development of clinical decision rules
Authors: Bilén Katarina , Ponzer Sari , Ottosson Carin , Castrén Maaret , Pettersson Hans 
Published: September 2012

Objectives(1) Validate an existing clinical tool for assessing risk after deliberate self-harm (DSH), Manchester Self-Harm Rule, in a new setting and new population, (2) develop a clinical decision rule based on factors associated with repeated self-harm in a Swedish population and (3) compare these rules.DesignA consecutive series of 1524 patients attending one of Scandinavia's largest emergency departments (ED) due to DSH during a 3-year period were included. Explanatory factors were collected from hospital charts and national databases. A nationwide register-based follow-up of new DSH episode or death by suicide within 6 months was used. We used logistic regression, area under the curve and classification trees to identify factors associated with repetition. To evaluate the ability of different decision rules to identify patients who will repeat DSH, we calculated the sensitivity and specificity.Main outcome measureRepeated DSH or suicide within 6 months.ResultsThe cumulative incidence for patients repeating within 6 months was 20.3% (95% CI 18.0% to 22.0%). Application of Manchester Self-Harm Rule to our material yielded a sensitivity of 89% and a specificity of 21%. The clinical decision rule based on four factors associated with repetition in the Swedish population yielded a sensitivity of 90% and a specificity of 18%.ConclusionsApplication of either rules, with high sensitivity, may facilitate assessment in the ED and help focus right resources on patients at a higher risk. Irrespective of the choice of decision rule, it is difficult to separate those who will repeat from those who will not due to low specificity.
Sensitive troponin assay predicts outcome in syncope
Authors: Reed Matthew J , Mills Nicholas L , Weir Christopher J 
Published: September 2012

AimsTo assess whether plasma troponin concentration measured by a sensitive assay can predict 1-month and 1-year serious outcome, or all-cause death in patients presenting with syncope to the emergency department (ED).MethodsProspective cohort study of admitted adult patients presenting to the ED after an episode of syncope who had plasma troponin measured 12 h after syncope using the ARCHITECTSTATsensitive troponin I assay (Abbott Diagnostics). Primary endpoints were the composite endpoint of serious outcome or all-cause death at 1 month and 1 year.ResultsBetween 1 March 2007 and 22 July 2008, 338 of 528 patients admitted from the ED with syncope had plasma troponin concentrations determined. Troponin concentrations were above the limit of detection in 261 (77%) patients. Patients numbering 120 (36%) had a troponin concentration ≥0.03 ng/ml (99th percentile of normal reference population), and 66 (20%) had concentrations ≥0.05 ng/ml (local diagnostic threshold for myocardial infarction). The proportion of patients with a composite serious outcome increased across patients stratified into quintiles based on peak troponin concentration at 1 month (0%, 9%, 13%, 26%, 70%) and at 1 year (10%, 22%, 26%, 52%, 85%).ConclusionsThe majority of patients admitted from the ED with syncope have detectable plasma troponin concentrations. Peak troponin concentration was associated with increasing risk of serious outcome and death, and this risk increases with higher troponin concentrations. Troponin may have a future role in the risk stratification of patients with syncope.
Vitamin D deficiency in children presenting to the emergency department: a growing concern. Vitamin D deficiency in Birmingham's children: presentation to the emergency department
Authors: Kehler Lisa , Verma Sapna , Krone Ruth , Roper Emily 
Published: September 2012

IntroductionThe increase in detected vitamin D deficiency appears to be multifactorial: an increasingly multicultural society, reduced exposure to sunlight due to concern about skin cancer and a more sedentary lifestyle and dietary changes within the population.MethodsThis was a retrospective survey of children found to be vitamin D deficient after attending the emergency department from March 2009 until March 2010. These data were then subdivided according to their age, ethnic origin, presenting complaint and biochemical associated features.ResultsWe identified 89 patients with a low vitamin D level (total vitamin D levels less than 50 nmol/l), with 83% of those having very low vitamin D levels (less than 25 nmol/l). The most common presenting features were abdominal pain (19%), a seizure (17%) and limb pain (15%). The most common ethnic origins in our series were Pakistani (37%) followed by black African (11.2%).ConclusionsVitamin D deficiency should be considered in children with pigmented skin presenting with a range of symptoms. The detected vitamin D deficiency probably represents only a very small proportion of the vitamin D deficiency in children in Birmingham.
A thromboembolic model for the efficacy and safety evaluation of combined mechanical and pharmacologic revascularization strategies
Authors: Gounis Matthew J , Nogueira Raul G , Mehra Manik , Chueh Juyu , Wakhloo Ajay K 
Published: September 2012

Background and purposeRecanalization strategies mediated by intra-arterial fibrinolytic therapy in combination with mechanical clot disruption may be a more effective treatment approach than either therapy used alone. There are few preclinical animal models to evaluate these strategies. Here we report on a model to simultaneously evaluate both of these treatment approaches.MethodsAllogeneic clot was injected through the 6 F guide catheter after creating >50% luminal stenosis of the common carotid arteries of New Zealand White rabbits. The stenosis was released after 1 h, allowing sufficient time for clot–vessel wall interaction. Occlusion was confirmed and each vessel was assigned to receive either balloon angioplasty alone, intra-arterial tissue plasminogen activator (tPA, Alteplase, Genentech, San Francisco, California, USA), tPA delivery through prototype balloon infusion wire (NIT Therapeutics, Pittsburgh, Pennsylvania, USA), partial stent deployment or partial stent deployment with locally delivered tPA. The negative control received no treatment.ResultsIn vivo revascularization Thrombolysis in Cerebral Infarction (TICI) score revealed that the balloon infusion wire achieved a stable and higher revascularization score of TICI 2B, with a lower dose of tPA in comparison with other treatment strategies. All treatment strategies resulted in endothelial denudation and exposure of the internal elastic lamina.ConclusionsThe proposed animal model permits reliable and consistent thromboembolic occlusion of the target vasculature and allows for an assessment of both pharmacologic and mechanical revascularization strategies for acute ischemic stroke.