bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental Study on the Cavitation Characteristics of an Oil Jet Pump With Multiple Nozzles for the Lubrication System in a Steam Turbine
Authors: Zhang Jun , Mao Jing-ru , Wang Shun-sen , Wu Bin , Yuan Hao , Wang Kai-ge , Zhang Jun-jie , Sun Peng
Published: June 2014

Cavitation characteristics of oil jet pumps with multiple nozzles were studied using high frequency response pressure transducers with Mobile DTE Light Oil in experiment, which has an environment the same as that in the lubrication system of the steam turbine in a power plant. The influence of working oil pressure, pressure ratio, and area ratio on cavitation characteristics were studied with the area ratio ranging from 4 to 9, and the working oil pressure ranging from 1.8 to 2.8 MPa. Results show that the cavitation erosion on the throat surface is caused by the intense shear layer of high-speed jet in the throat, which leads to the collapse of vortex cavitation bubbles near the throat surface in an oil jet pump with multiple nozzles. What is more, the vortex cavitation is difficult to eradicate in an oil jet pump with multiple nozzles for the lubrication system of a steam turbine. However, there is a working point with low cavitation intensity, which is also the high efficiency point that ensures both relative safety and high efficiency. This study provides quantitative relation for the determination of working oil pressure, area ratio, and pressure ratio of an oil jet pump with multiple nozzles, which is significant for engineering.
Science Signaling
Podcast: 10 June 2014
Authors: Hynes Nancy E. , VanHook Annalisa M.
Published: June 2014

The copper-binding enzyme Memo promotes breast cancer metastasis.
Creating Separate Channel Parts
Authors: Gough Nancy R.
Published: June 2014

Calcium-regulated cleavage of the pore-forming subunit of voltage-dependent calcium channels attenuates channel activity.
Resistance to Colistin Associated with a Single Amino Acid Change in Protein PmrB among Klebsiella pneumoniae Isolates of Worldwide Origin
Authors: Jayol Aurélie , Poirel Laurent , Brink Adrian , Villegas Maria-Virginia , Yilmaz Mesut , Nordmann Patrice
Published: June 2014

A series of colistin-resistant
Klebsiella pneumoniae
isolates recovered from different countries was investigated in order to evaluate the involvement of the PmrA/PmrB two-component system in this resistance. Six isolates possessed a mutated PmrB protein, which is encoded by the
pmrB
gene, part of the
pmrCAB
operon involved in lipopolysaccharide modification. The same amino acid substitution (Thr157Pro) in PmrB was identified in the six isolates. The six isolates belonged to four distinct clonal groups, recovered in South Africa (sequence type 14 [ST14]), Turkey (ST101), and Colombia (ST258 and ST15). Three out of the four clones produced a carbapenemase, OXA-181, OXA-48, or KPC-3, while a single isolate did not produce any carbapenemase. Expression assays revealed an overexpression of the
pmrA
(70-fold),
pmrB
(70-fold),
pmrC
(170-fold), and
pmrK
(40-fold) genes in the
pmrB
-mutated isolate compared to expression of the
pmrB
wild-type isogenic
K. pneumoniae
isolate, confirming that the PmrB substitution was responsible for increased expression levels of those genes. Complementation assays leading to the expression of a wild-type PmrB protein restored the susceptibility to colistin in all isolates, confirming that the substitution in PmrB was responsible for the resistance phenotype. This study identified a key amino acid located in the PmrB protein as being responsible for the overexpression of
pmrCAB
and
pmrHFIJKLM
operons, leading to resistance to colistin.
Treatment of Murine Cerebral Malaria by Artemisone in Combination with Conventional Antimalarial Drugs: Antiplasmodial Effects and Immune Responses
Authors: Guiguemde W. Armand , Hunt Nicholas H. , Guo Jintao , Marciano Annael , Haynes Richard K. , Clark Julie , Guy R. Kiplin , Golenser Jacob
Published: June 2014

The decreasing effectiveness of antimalarial therapy due to drug resistance necessitates constant efforts to develop new drugs. Artemisinin derivatives are the most recent drugs that have been introduced and are considered the first line of treatment, but there are already indications ofPlasmodium falciparumresistance to artemisinins. Consequently, drug combinations are recommended for prevention of the induction of resistance. The research here demonstrates the effects of novel combinations of the new artemisinin derivative, artemisone, a recently described 10-alkylamino artemisinin derivative with improved antimalarial activity and reduced neurotoxicity. We here investigate its ability to killP. falciparumin a high-throughputin vitroassay and to protect mice against lethal cerebral malaria caused byPlasmodium bergheiANKA when used alone or in combination with established antimalarial drugs. Artemisone effects againstP. falciparumin vitrowere synergistic with halofantrine and mefloquine, and additive with 25 other drugs, including chloroquine and doxycycline. The concentrations of artemisone combinations that were toxic against THP-1 cellsin vitrowere much higher than their effective antimalarial concentration. Artemisone, mefloquine, chloroquine, or piperaquine given individually mostly protected mice against cerebral malaria caused byP. bergheiANKA but did not prevent parasite recrudescence. Combinations of artemisone with any of the other three drugs did completely cure most mice of malaria. The combination of artemisone and chloroquine decreased the ratio of proinflammatory (gamma interferon, tumor necrosis factor) to anti-inflammatory (interleukin 10 [IL-10], IL-4) cytokines in the plasma ofP. berghei-infected mice. Thus, artemisone in combinations with other antimalarial drugs might have a dual action, both killing parasites and limiting the potentially deleterious host inflammatory response.
Multidisciplinary Analysis of a Nontoxigenic Clostridium difficile Strain with Stable Resistance to Metronidazole
Authors: Moura Ines , Monot Marc , Tani Chiara , Spigaglia Patrizia , Barbanti Fabrizio , Norais Nathalie , Dupuy Bruno , Bouza Emilio , Mastrantonio Paola
Published: June 2014

Stable resistance to metronidazole in a nontoxigenic
Clostridium difficile
strain was investigated at both the genomic and proteomic levels. Alterations in the metabolic pathway involving the pyruvate-ferredoxin oxidoreductase were found, suggesting that reduction of metronidazole, required for its activity, may be less efficient in this strain. Proteomic studies also showed a cellular response to oxidative stress.
Heterogeneity of Molecular Resistance Patterns in Antimony-Resistant Field Isolates of Leishmania Species from the Western Mediterranean Area
Authors: Jeddi Fakhri , Mary Charles , Aoun Karim , Harrat Zoubir , Bouratbine Aïda , Faraut Françoise , Benikhlef Rezika , Pomares Christelle , Pratlong Francine , Marty Pierre , Piarroux Renaud
Published: June 2014

Antimonials remain the first-line treatment for the various manifestations of leishmaniasis in most areas where the disease is endemic, and increasing cases of therapeutic failure associated with parasite resistance have been reported. In this study, we assessed the molecular status of 47 clinical isolates of
Leishmania
causing visceral and cutaneous leishmaniasis from Algeria, Tunisia, and southern France. In total, we examined 14 genes that have been shown to exhibit significant variations in DNA amplification, mRNA levels, or protein expression with respect to resistance to antimonials. The gene status of each clinical isolate was assessed via qPCR and qRT-PCR. We then compared the molecular pattern against the phenotype determined via an
in vitro
sensitivity test of the clinical isolates against meglumine antimoniate, which is considered the reference technique. Our results demonstrate significant DNA amplification and/or RNA overexpression in 56% of the clinical isolates with the resistant phenotype. All clinical isolates that exhibited significant overexpression of at least 2 genes displayed a resistant phenotype. Among the 14 genes investigated, 10 genes displayed either significant amplification or overexpression in at least 1 clinical isolate; these genes are involved in several metabolic pathways. Moreover, various gene associations were observed depending on the clinical isolates, supporting the multifactorial nature of
Leishmania
resistance. Molecular resistance features were found in the 3
Leishmania
species investigated (
Leishmania infantum
,
Leishmania major
, and
Leishmania killicki
). To our knowledge, this is the first report of the involvement of molecular resistance genes in field isolates of
Leishmania major
and
Leishmania killicki
with the resistance phenotype.
Scalable Preparation and Differential Pharmacologic and Toxicologic Profiles of Primaquine Enantiomers
Authors: Nanayakkara N. P. Dhammika , Tekwani Babu L. , Herath H. M. T. Bandara , Sahu Rajnish , Gettayacamin Montip , Tungtaeng Anchalee , van Gessel Yvonne , Baresel Paul , Wickham Kristina S. , Bartlett Marilyn S. , Fronczek Frank R. , Melendez Victor , Ohrt Colin , Reichard Gregory A. , McChesney James D. , Rochford Rosemary , Walker Larry A.
Published: June 2014

Hematotoxicity in individuals genetically deficient in glucose-6-phosphate dehydrogenase (G6PD) activity is the major limitation of primaquine (PQ), the only antimalarial drug in clinical use for treatment of relapsing
Plasmodium vivax
malaria. PQ is currently clinically used in its racemic form. A scalable procedure was developed to resolve racemic PQ, thus providing pure enantiomers for the first time for detailed preclinical evaluation and potentially for clinical use. These enantiomers were compared for antiparasitic activity using several mouse models and also for general and hematological toxicities in mice and dogs. (+)-(
S
)-PQ showed better suppressive and causal prophylactic activity than (−)-(
R
)-PQ in mice infected with
Plasmodium berghei
. Similarly, (+)-(
S
)-PQ was a more potent suppressive agent than (−)-(
R
)-PQ in a mouse model of
Pneumocystis carinii
pneumonia. However, at higher doses, (+)-(
S
)-PQ also showed more systemic toxicity for mice. In beagle dogs, (+)-(
S
)-PQ caused more methemoglobinemia and was toxic at 5 mg/kg of body weight/day given orally for 3 days, while (−)-(
R
)-PQ was well tolerated. In a novel mouse model of hemolytic anemia associated with human G6PD deficiency, it was also demonstrated that (−)-(
R
)-PQ was less hemolytic than (+)-(
S
)-PQ for the G6PD-deficient human red cells engrafted in the NOD-SCID mice. All these data suggest that while (+)-(
S
)-PQ shows greater potency in terms of antiparasitic efficacy in rodents, it is also more hematotoxic than (−)-(
R
)-PQ in mice and dogs. Activity and toxicity differences of PQ enantiomers in different species can be attributed to their different pharmacokinetic and metabolic profiles. Taken together, these studies suggest that (−)-(
R
)-PQ may have a better safety margin than the racemate in human.
Identification of a Novel Clone, ST736, among Enterococcus faecium Clinical Isolates and Its Association with Daptomycin Nonsusceptibility
Authors: Wang Guiqing , Kamalakaran Sitharthan , Dhand Abhay , Huang Weihua , Ojaimi Caroline , Zhuge Jian , Yee Leslie Lee , Mayigowda Pramod , Surendraiah Pavan Kumar Makam , Dimitrova Nevenka , Fallon John T.
Published: June 2014

Resistance to daptomycin in enterococcal clinical isolates remains rare but is being increasingly reported in the United States and worldwide. There are limited data on the genetic relatedness and microbiological and clinical characteristics of daptomycin-nonsusceptible enterococcal clinical isolates. In this study, we assessed the population genetics of daptomycin-nonsusceptible
Enterococcus faecium
(DNSE) clinical isolates by multilocus sequence typing (MLST) and whole-genome sequencing analysis. Forty-two nonduplicate DNSE isolates and 43 randomly selected daptomycin-susceptible
E. faecium
isolates were included in the analysis. All
E. faecium
isolates were recovered from patients at a tertiary care medical center in suburban New York City from May 2009 through December 2013. The daptomycin MICs of the DNSE isolates ranged from 6 to >256 μg/ml. Three major clones of
E. faecium
(ST18, ST412, and ST736) were identified among these clinical isolates by MLST and whole-genome sequence-based analysis. A newly recognized clone, ST736, was seen in 32 of 42 (76.2%) DNSE isolates and in only 14 of 43 (32.6%) daptomycin-susceptible
E. faecium
isolates (
P
< 0.0001). This report provides evidence of the association between
E. faecium
clone ST736 and daptomycin nonsusceptibility. The identification and potential spread of this novel
E. faecium
clone and its association with daptomycin nonsusceptibility constitute a challenge for patient management and infection control at our medical center.
KAF156 Is an Antimalarial Clinical Candidate with Potential for Use in Prophylaxis, Treatment, and Prevention of Disease Transmission
Authors: Kuhen Kelli L. , Chatterjee Arnab K. , Rottmann Matthias , Gagaring Kerstin , Borboa Rachel , Buenviaje Jennifer , Chen Zhong , Francek Carolyn , Wu Tao , Nagle Advait , Barnes S. Whitney , Plouffe David , Lee Marcus C. S. , Fidock David A. , Graumans Wouter , van de Vegte-Bolmer Marga , van Gemert Geert J. , Wirjanata Grennady , Sebayang Boni , Marfurt Jutta , Russell Bruce , Suwanarusk Rossarin , Price Ric N. , Nosten Francois , Tungtaeng Anchalee , Gettayacamin Montip , Sattabongkot Jetsumon , Taylor Jennifer , Walker John R. , Tully David , Patra Kailash P. , Flannery Erika L. , Vinetz Joseph M. , Renia Laurent , Sauerwein Robert W. , Winzeler Elizabeth A. , Glynne Richard J. , Diagana Thierry T.
Published: June 2014

Renewed global efforts toward malaria eradication have highlighted the need for novel antimalarial agents with activity against multiple stages of the parasite life cycle. We have previously reported the discovery of a novel class of antimalarial compounds in the imidazolopiperazine series that have activity in the prevention and treatment of blood stage infection in a mouse model of malaria. Consistent with the previously reported activity profile of this series, the clinical candidate KAF156 shows blood schizonticidal activity with 50% inhibitory concentrations of 6 to 17.4 nM against
P. falciparum
drug-sensitive and drug-resistant strains, as well as potent therapeutic activity in a mouse models of malaria with 50, 90, and 99% effective doses of 0.6, 0.9, and 1.4 mg/kg, respectively. When administered prophylactically in a sporozoite challenge mouse model, KAF156 is completely protective as a single oral dose of 10 mg/kg. Finally, KAF156 displays potent
Plasmodium
transmission blocking activities both
in vitro
and
in vivo
. Collectively, our data suggest that KAF156, currently under evaluation in clinical trials, has the potential to treat, prevent, and block the transmission of malaria.
Population Pharmacokinetic-Pharmacodynamic Analysis of Voriconazole and Anidulafungin in Adult Patients with Invasive Aspergillosis
Authors: Liu Ping , Mould Diane R.
Published: June 2014

To evaluate the exposure-response relationships for efficacy and safety of voriconazole and anidulafungin in adult patients with invasive aspergillosis (IA), a population pharmacokinetic-pharmacodynamic (PK-PD) analysis was performed with data from a phase 3, prospective, double-blind, comparative study evaluating voriconazole and anidulafungin combination therapy versus voriconazole (and placebo) monotherapy. Anidulafungin/placebo treatment duration was 2 to 4 weeks, and voriconazole treatment duration was 6 weeks. Efficacy (6-week all-causality mortality and 6-week global response [
n
= 176]) and safety (hepatic [
n
= 238], visual [
n
= 199], and psychiatric [
n
= 183] adverse events [AEs]) endpoints were analyzed separately using a binary logistic regression model. In IA patients receiving voriconazole monotherapy, no positive associations between voriconazole exposure and efficacy or safety were identified. In IA patients receiving combination therapy, no positive associations between voriconazole or anidulafungin exposures and efficacy were identified. The 6-week survival rate tended to increase as anidulafungin treatment duration increased; this finding should be considered with caution. Additionally, in IA patients receiving combination therapy, a positive association between voriconazole and anidulafungin exposures (area under the curve [AUC] and trough concentration [
C
min
]) and hepatic AEs was established; a weak positive association between voriconazole exposure (AUC and
C
min
) and psychiatric AEs was also established, but no association between voriconazole exposure and visual AEs was identified. Besides the drug exposures, no other covariates (i.e., CYP2C19 genotype status, age, weight, body mass index, sex, race, or neutropenia status) were identified as significant predictors of the efficacy and safety endpoints in IA patients. This study was registered on
ClinicalTrials.gov
(NCT00531479).
Safety and Pharmacokinetics of XOMA 3AB, a Novel Mixture of Three Monoclonal Antibodies against Botulinum Toxin A
Authors: Nayak S. U. , Griffiss J. M. , McKenzie R. , Fuchs E. J. , Jurao R. A. , An A. T. , Ahene A. , Tomic M. , Hendrix C. W. , Zenilman J. M.
Published: June 2014

Botulinum neurotoxin A is a category A bioterrorism agent. Current antitoxin therapies are scarce and produce adverse reactions. XOMA 3AB consists of 3 IgG1 monoclonal antibodies (MAbs), each with a distinct human or humanized variable region, which bind to distinct epitopes on botulinum neurotoxin serotype A. This first-in-human study evaluated the safety and pharmacokinetics (PK) of escalating doses of XOMA 3AB administered intravenously (i.v.) to healthy adults. In this double-blind placebo-controlled dose escalation study, 3 cohorts of 8 healthy subjects received a single intravenous dose of XOMA 3AB or placebo at a 3:1 ratio. Follow-up examinations included physical examinations, hematology and chemistry blood tests, electrocardiograms, and pharmacokinetics. Pharmacokinetic parameters were estimated using noncompartmental methods. There were no infusion discontinuations or hypersensitivity reactions. Two or more subjects experienced headache, hyperglycemia, or anemia; none was dose related. All adverse events (AEs) were mild to moderate except for an episode of exercise-induced elevation of a subject's creatine phosphokinase (CPK) level, unrelated to XOMA 3AB. Concentration-time plots demonstrated a peak in MAb concentrations 1 to 2 h after completion of the infusion, after which the levels declined in a biexponential decay pattern for all analytes. For each MAb, the maximum concentration of drug in serum (
C
max
) and the area under the concentration-time curve from 0 to infinity (AUC
inf
) increased as the dose increased. Clearance of the humanized mouse MAb was more rapid than that of the two fully human MAbs, particularly at the lowest dose. None of the MAbs was immunogenic. At the doses administered, XOMA 3AB was well tolerated. These safety findings support further investigation of XOMA 3AB as a potential agent for botulism treatment and postexposure prophylaxis. (This study has been registered at ClinicalTrials.gov under registration no. NCT01357213.)
Serratia marcescens ShlA Pore-Forming Toxin Is Responsible for Early Induction of Autophagy in Host Cells and Is Transcriptionally Regulated by RcsB
Authors: Di Venanzio Gisela , Stepanenko Tatiana M. , García Véscovi Eleonora
Published: June 2014

Serratia marcescens
is a Gram-negative bacterium that thrives in a wide variety of ambient niches and interacts with an ample range of hosts. As an opportunistic human pathogen, it has increased its clinical incidence in recent years, being responsible for life-threatening nosocomial infections.
S. marcescens
produces numerous exoproteins with toxic effects, including the ShlA pore-forming toxin, which has been catalogued as its most potent cytotoxin. However, the regulatory mechanisms that govern ShlA expression, as well as its action toward the host, have remained unclear. We have shown that
S. marcescens
elicits an autophagic response in host nonphagocytic cells. In this work, we determine that the expression of ShlA is responsible for the autophagic response that is promoted prior to bacterial internalization in epithelial cells. We show that a strain unable to express ShlA is no longer able to induce this autophagic mechanism, while heterologous expression of ShlA/ShlB suffices to confer on noninvasive
Escherichia coli
the capacity to trigger autophagy. We also demonstrate that
shlBA
harbors a binding motif for the RcsB regulator in its promoter region. RcsB-dependent control of
shlBA
constitutes a feed-forward regulatory mechanism that allows interplay with flagellar-biogenesis regulation. At the top of the circuit, activated RcsB downregulates expression of flagella by binding to the
flhDC
promoter region, preventing FliA-activated transcription of
shlBA
. Simultaneously, RcsB interaction within the
shlBA
promoter represses ShlA expression. This circuit offers multiple access points to fine-tune ShlA production. These findings also strengthen the case for an RcsB role in orchestrating the expression of
Serratia
virulence factors.
Microbiota-Driven Immune Cellular Maturation Is Essential for Antibody-Mediated Adaptive Immunity to Staphylococcus aureus Infection in the Eye
Authors: Zaidi Tanweer , Zaidi Tauqeer , Cywes-Bentley Colette , Lu Roger , Priebe Gregory P. , Pier Gerald B.
Published: June 2014

As an immune-privileged site, the eye, and particularly the outer corneal surface, lacks resident mature immune effector cells. Physical barriers and innate mediators are the best-described effectors of immunity in the cornea. When the barriers are breached, infection can result in rapid tissue destruction, leading to loss of visual acuity and frank blindness. To determine the cellular and molecular components needed for effective adaptive immunity on the corneal surface, we investigated which immune system effectors were required for protection against
Staphylococcus aureus
corneal infections in mice, which are a serious cause of human eye infections. Both systemically injected and topically applied antibodies to the conserved cell surface polysaccharide poly-
N
-acetylglucosamine (PNAG) were effective at mediating reductions in corneal pathology and bacterial levels. Additional host factors impacting protection included intercellular adhesion molecule 1 (ICAM-1)-dependent polymorphonuclear leukocyte (PMN) recruitment, functional CD4
+
T cells, signaling via the interleukin-17 (IL-17) receptor, and IL-22 production. In germfree mice, there was no protective efficacy of antibody to PNAG due to the lack of LY6G
+
inflammatory cell coeffector recruitment to the cornea. Protection was manifest after 3 weeks of exposure to conventional mice and acquisition of a resident microbiota. We conclude that in the anterior eye, ICAM-1-mediated PMN recruitment to the infected cornea along with endogenous microbiota-matured CD4
+
T cells producing both IL-17 and IL-22 is required for antibody to PNAG to protect against
S. aureus
infection.
Leucine-Responsive Regulatory Protein Lrp and PapI Homologues Influence Phase Variation of CS31A Fimbriae
Authors: Graveline Richard , Garneau Philippe , Martin Christine , Mourez Michaël , Hancock Mark A. , Lavoie Rémi , Harel Josée
Published: June 2014

CS31A, a K88-related surface antigen specified by theclpoperon, is a member of the type P family of adhesive factors and plays a key role in the establishment of disease caused by septicemic and enterotoxigenicEscherichia colistrains. Its expression is under the control of methylation-dependent transcriptional regulation, for which the leucine-responsive regulatory protein (Lrp) is essential. CS31A is preferentially in the OFF state and exhibits distinct regulatory features compared to the regulation of other P family members. In the present study, surface plasmon resonance and DNase I protection assays showed that Lrp binds to the distal moiety of theclpregulatory region with low micromolar affinity compared to its binding to the proximal moiety, which exhibits stronger, nanomolar affinity. The complex formation was also influenced by the addition of PapI or FooI, which increased the affinity of Lrp for theclpdistal and proximal regions and was required to induce phase variation. The influence of PapI or FooI, however, was predominantly associated with a more complete shutdown ofclpexpression, in contrast to what has previously been observed with AfaF (a PapI ortholog). Taken together, these results suggest that the preferential OFF state observed in CS31A cells is mainly due to the weak interaction of the leucine-responsive regulatory protein with theclpdistal region and that the PapI homolog favors the OFF phase. Within the large repertoire of fimbrial variants in the P family, our study illustrates that having a fimbrial operon that lacks its own PapI ortholog allows it to be more flexibly regulated by other orthologs in the cell.
Error-Prone Processing of Apurinic/Apyrimidinic (AP) Sites by PolX Underlies a Novel Mechanism That Promotes Adaptive Mutagenesis in Bacillus subtilis
Authors: Barajas-Ornelas Rocío del Carmen , Ramírez-Guadiana Fernando H. , Juárez-Godínez Rafael , Ayala-García Victor M. , Robleto Eduardo A. , Yasbin Ronald E. , Pedraza-Reyes Mario
Published: June 2014

In growing cells, apurinic/apyrimidinic (AP) sites generated spontaneously or resulting from the enzymatic elimination of oxidized bases must be processed by AP endonucleases before they compromise cell integrity. Here, we investigated how AP sites and the processing of these noncoding lesions by the AP endonucleases Nfo, ExoA, and Nth contribute to the production of mutations (
hisC952
,
metB5
, and
leuC427
) in starved cells of the
Bacillus subtilis
YB955 strain. Interestingly, cells from this strain that were deficient for Nfo, ExoA, and Nth accumulated a greater amount of AP sites in the stationary phase than during exponential growth. Moreover, under growth-limiting conditions, the triple
nfo exoA nth
knockout strain significantly increased the amounts of adaptive
his
,
met
, and
leu
revertants produced by the
B. subtilis
YB955 parental strain. Of note, the number of stationary-phase-associated reversions in the
his
,
met
, and
leu
alleles produced by the
nfo exoA nth
strain was significantly decreased following disruption of
polX
. In contrast, during growth, the reversion rates in the three alleles tested were significantly increased in cells of the
nfo exoA nth
knockout strain deficient for polymerase X (PolX). Therefore, we postulate that adaptive mutations in
B. subtilis
can be generated through a novel mechanism mediated by error-prone processing of AP sites accumulated in the stationary phase by the PolX DNA polymerase.
Selection of
dinB
Alleles Suppressing Survival Loss upon
dinB
Overexpression in Escherichia coli
Authors: Benson Ryan W. , Cafarelli Tiziana M. , Rands Thomas J. , Lin Ida , Godoy Veronica G.
Published: June 2014

Escherichia coli
strains overproducing DinB undergo survival loss; however, the mechanisms regulating this phenotype are poorly understood. Here we report a genetic selection revealing DinB residues essential to effect this loss-of-survival phenotype. The selection uses strains carrying both an antimutator allele of DNA polymerase III (Pol III) α-subunit (
dnaE915
) and either chromosomal or plasmid-borne
dinB
alleles. We hypothesized that
dnaE915
cells would respond to DinB overproduction differently from
dnaE

+

cells because the
dnaE915
allele is known to have an altered genetic interaction with
dinB

+

compared to its interaction with
dnaE

+

. Notably, we observe a loss-of-survival phenotype in
dnaE915
strains with either a chromosomal catalytically inactive
dinB
(
D103N
) allele or a low-copy-number plasmid-borne
dinB

+

upon DNA damage treatment. Furthermore, we find that the loss-of-survival phenotype occurs independently of DNA damage treatment in a
dnaE915
strain expressing the catalytically inactive
dinB
(
D103N
) allele from a low-copy-number plasmid. The selective pressure imposed resulted in suppressor mutations that eliminated growth defects. The
dinB
intragenic mutations examined were either base pair substitutions or those that we inferred to be loss of function (i.e., deletions and insertions). Further analyses of selected novel
dinB
alleles, generated by single-base-pair substitutions in the
dnaE915
strain, indicated that these no longer effect loss of survival upon overproduction in
dnaE

+

strains. These mutations are mapped to specific areas of DinB; this permits us to gain insights into the mechanisms underlying the DinB-mediated overproduction loss-of-survival phenotype.
A Model for the Evolution of Biological Specificity: a Cross-Reacting DNA-Binding Protein Causes Plasmid Incompatibility
Authors: Hyland Edel M. , Wallace Edward W. J. , Murray Andrew W.
Published: June 2014

Few biological systems permit rigorous testing of how changes in DNA sequence give rise to adaptive phenotypes. In this study, we sought a simplified experimental system with a detailed understanding of the genotype-to-phenotype relationship that could be altered by environmental perturbations. We focused on plasmid fitness, i.e., the ability of plasmids to be stably maintained in a bacterial population, which is dictated by the plasmid's replication and segregation machinery. Although plasmid replication depends on host proteins, the type II plasmid partitioning (Par) machinery is entirely plasmid encoded and relies solely on three components:
parC
, a centromere-like DNA sequence, ParR, a DNA-binding protein that interacts with
parC
, and ParM, which forms actin-like filaments that push two plasmids away from each other at cell division. Interactions between the Par operons of two related plasmids can cause incompatibility and the reduced transmission of one or both plasmids. We have identified segregation-dependent plasmid incompatibility between the highly divergent Par operons of plasmids pB171 and pCP301. Genetic and biochemical studies revealed that the incompatibility is due to the functional promiscuity of the DNA-binding protein ParR
pB171
, which interacts with both
parC
DNA sequences to direct plasmid segregation, indicating that the lack of DNA binding specificity is detrimental to plasmid fitness in this environment. This study therefore successfully utilized plasmid segregation to dissect the molecular interactions between genotype, phenotype, and fitness.
Robotic-assisted laparoscopic repair of a vesicovaginal fistula: a time-consuming novelty or an effective tool?
Authors: Pietersma Carsten S , Schreuder Henk W R , Kooistra Anko , Schraffordt Koops Steven E
Published: June 2014

Vesicovaginal fistulas are a rare complication of hysterectomy. When conservative therapy fails, vaginal or abdominal repair is necessary. A robotic-assisted laparoscopic approach can be a useful tool to repair complex fistulas. A 50-year-old woman with a vesicovaginal fistula located at the top of the vagina, was treated with robotic-assisted laparoscopic repair. The fistula tissue was removed from the vaginal wall and bladder, and epiploic of the sigmoid was interposed in between. The total operation time was 104 min. The hospital stay was 3 days; no complications occurred. Cystography 6 weeks and 6 months postoperative confirmed a successful repair. A review of current literature is presented regarding the application of robotic assistance during this procedure. The presented case shows that robotic-assisted laparoscopic repair of a vesicovaginal fistula seems to be a feasible technique with promising results.
Belly button piercings: a saving grace? A patent urachus presenting in a 17-year-old girl
Authors: Bannon Aidan , Black Patrick , Turner Joanna , Gray Sam , Kirk Stephen
Published: June 2014

We report the case of a 17-year-old girl who presented to the accident and emergency department with dysuria and foul smelling, bloody discharge from her umbilicus. The definitive diagnosis was that of a patent urachus, which is a fistulous communication between the bladder and the umbilicus, usually diagnosed in early infancy. The incidence of a patent urachus is approximately 1 in 70 000 in the general population. It is highly likely that removal of a recent belly button piercing resulted in the acute presentation by completing the fistulous tract to the skin. This case is of clinical relevance as the diagnosis was missed 18 months prior with a milder presentation. The recommended treatment option is surgical excision due to the potential risk of malignant change, with urachal adenocarcinoma accounting for 0.3% of all bladder cancers.
Association of birth of girls with postnatal depression and exclusive breastfeeding: an observational study
Authors: Jain Akanksha , Tyagi Prashant , Kaur Prabhjeet , Puliyel Jacob , Sreenivas Vishnu
Published: June 2014

Objectives and hypothesis

To examine the influence of gender of the baby on exclusive breastfeeding and incidence of postnatal depression (PND). We hypothesise that in a society with a male gender bias there may be more PND and less exclusive breastfeeding of the girl child.

Design

Prospective study.

Setting

The study was conducted in an urban, tertiary hospital in Delhi.

Participants

Mothers delivering normally with their babies roomed-in.1537 eligible women participated in the study.

Primary and secondary outcome measures

Exclusive breastfeeding within the first 48 h of life and score on the Edinburgh Postnatal Depression Scale (EPDS) were recorded.

Results

3466 babies were born in the hospital. There were 792 girls for every 1000 boys. Among primiparous women, the sex ratio was 901 girls per 1000 boys. For second babies, the sex ratio was 737:1000. If the first child was a girl the birth ratio fell to 632. 1026 mothers were exclusively breastfeeding. Exclusive breastfeeding of boys was significantly higher (70.8% vs 61.5%, p<0.001). The EPDS score was significantly higher with the birth of girls (EPDS 6.0±3.39 vs 5.4±2.87, p<0.01). Women with an EPDS score >11 were less likely to exclusively breastfeed (p<0.01).

Conclusions

The results point to a pro-male gender bias evidenced by a low sex ratio at birth, higher EPDS score in mothers of girls and less breastfeeding of female children.
A multidisciplinary, multifaceted improvement initiative to eliminate mislabelled laboratory specimens at a large tertiary care hospital
Authors: Seferian Edward G , Jamal Salima , Clark Kathleen , Cirricione Mary , Burnes-Bolton Linda , Amin Mahul , Romanoff Neil , Klapper Ellen
Published: June 2014

Objectives

To sustainably reduce the rate of mislabelled laboratory specimens through implementation of a series of interventions as led and coordinated by a multidisciplinary performance improvement team.

Methods

The quality improvement project was performed at Cedars-Sinai Medical Center in Los Angeles, an academic care tertiary care hospital. Phlebotomy services are provided by unit-based nursing and dedicated laboratory-based phlebotomists. Baseline mislabelled specimen rate was obtained for a 6-month period prior to the first improvement intervention. Included in the rate of mislabelled specimens were inpatient blood and body fluid specimens. Anatomic pathology and cytological specimens and outpatient specimens were excluded. Mislabelled specimens were identified preanalytically, analytically or postanalytically. A specimen was considered mislabelled under the following circumstances: (1) specimen/requisition mismatch; (2) incorrect patient identifiers and (3) unlabelled specimen. Specimen mislabels were identified and validated monthly by a multidisciplinary team composed of personnel from nursing, laboratory and performance improvement. Performance improvement initiatives were implemented over a 2-year period with control charts used to assess improvement over time.

Results

The rate of mislabelled specimens varied by clinical area and decreased significantly over a 24-month time period during the initiative from 4.39 per 10 000 specimens to 1.97 per 10 000 specimens. All clinical areas achieved a significant decrease in the rate of mislabelled specimens except for the operating room and labour and delivery.

Conclusions

A multidisciplinary unit specific approach using performance improvement methodologies focusing on human factors can reliably and sustainably reduce the rate of mislabelled laboratory specimens in a large tertiary care hospital.
Value of repeat biopsy in lupus nephritis flares
Authors: Greloni G , Scolnik M , Marin J , Lancioni E , Quiroz C , Zacariaz J , De la Iglesia Niveyro P , Christiansen S , Pierangelo M A , Varela C F , Rosa-Diez G J , Catoggio L J , Soriano E R
Published: June 2014

Objectives

Renal flares are common in lupus nephritis (LN), and class switch is thought to be characteristic. There is no agreement on indications for performing a repeat renal biopsy. Our objective was to retrospectively review patients who had more than one renal biopsy performed on clinical indications, and analyse clinical, pathological and treatment changes after successive biopsies.

Methods

Forty-five patients with LN and one or more repeat renal biopsies were included, with a total of 116 biopsies.

Results

Of the 71 repeat biopsies, pathological transition occurred in 39 (54.9%). When having a previous biopsy with a proliferative lesion, class switch occurred in 55.6%, with 24.4% evolving into non-proliferative classes. When previous biopsy was class V, transition to other classes occurred in 58.3% and changes were all into proliferative classes. Conversion from one pure proliferative form to another (class III to class IV or vice versa) happened in 11.3% of the rebiopsies, with 62 rebiopsies (87.3%) leading to a change in the treatment regimen.

Conclusions

Histological transformations were common, and they occurred when the previous biopsy had non-proliferative lesions as well as when lesions were proliferative. Treatments were modified after repeat renal biopsy in the majority of patients. In this experience, kidney repeat biopsies were useful in guiding treatment of LN flares.
Necrotising fasciitis in systemic lupus erythematosus: a case report and literature review
Authors: Tung Chen Y , Isenberg D
Published: June 2014

Necrotising fasciitis (NF) is a rare infection of the subcutaneous tissue, known to be rapidly progressive and potentially fatal. Patients with systemic lupus erythematosus (SLE) may be predisposed to this condition, and early clinical recognition can be difficult. We report a case of necrotising fasciitis in a 26-year-old woman with SLE. She presented with painful swelling of her left leg, then developed clinical features of septic shock. Emergency debridement was performed. Intraoperative findings revealed NF and cultures grewPseudomonas aeruginosa. The patient survived after a lengthy hospital admission, following several further debridements complicated by recurrent chest sepsis and multiorgan failure. We also review and discuss the published cases of NF in SLE patients.
Vitamin D deficiency is common and associated with increased C-reactive protein in children and young adults with lupus: an Atherosclerosis Prevention in Pediatric Lupus Erythematosus substudy
Authors: Robinson Angela Byun , Tangpricha Vin , Yow Eric , Gurion Reut , McComsey Grace A , Schanberg Laura E
Published: June 2014

Objective

Epidemiological associations suggest vitamin D may play a role in inflammation and atherosclerosis. Using frozen serum and data from the Atherosclerosis Prevention in Pediatric Lupus Erythematosus (APPLE) trial, we assessed associations between 25-hydroxyvitamin D [25(OH)D] and measures of systemic lupus erythematosus (SLE) disease activity and cardiovascular risk.

Methods

Baseline APPLE serum samples were used to measure 25(OH)D levels. Logistic regression models for vitamin D deficiency [25(OH)D levels <20 ng/mL] were constructed using baseline variables collected as part of the trial, including race, season, latitude, disease duration, disease activity, high-sensitivity C-reactive protein (hsCRP), proteinuria, fasting lipids and carotid intima medial thickness (CIMT).

Results

Samples were available from 201 of 221 APPLE subjects; 61/201 (30%) had vitamin D deficiency at baseline. In univariable analysis, baseline vitamin D deficiency was associated with season (p<0.01), minority status (p<0.01), body mass index (p=0.04), duration of SLE (p<0.01), SLICC damage index (p=0.04), hsCRP (p<0.01), mean–max CIMT (p=0.01), LDL-cholesterol (p=0.03) and timed urine protein (p=0.03). In multivariable modelling, vitamin D deficiency was associated with age, latitude, season, minority status, proteinuria and hsCRP.

Conclusions

Vitamin D deficiency is common in paediatric lupus and is independently associated with elevated hsCRP, a marker of inflammation that predicts cardiovascular disease risk. Although association is not proof of causation, this association is novel in the paediatric SLE population and suggests that vitamin D deficiency may contribute to heightened inflammation and cardiovascular risk in this population.

Trial register number

NCT00065806.
Ultrasonographic features of the liver with cystic echinococcosis in sheep
Authors: Hussein Hussein Awad , Elrashidy Mohammed
Published: June 2014

Objectives

The present study was designed to gain information about the ultrasonographic features of livers with cystic echinococcosis, as well as to evaluate the use of ultrasonography for diagnosis of such disease in sheep.

Design

This was a retrospective study during the period April 2011 to March 2013.

Participants

A total of 22 Baladi sheep (aged three to six years) were included in this study. Based on clear hepatic ultrasonographic findings, all animals were classified into two groups: those with hepatic cysts (n=9) and without liver cysts (healthy liver, n=13).

Results

Biochemically, serum concentrations of γ‐glutamyl transferase, aspartate aminotransferase, total bilirubin and globulins were significantly increased (P<0.01), while albumin was lowered (P<0.01) in sheep with cystic livers. Ultrasonographic findings of diseased sheep livers revealed the presence of rounded, anechoic and unilocular hydatid cysts with ellipse circumference ranged from 6–10 cm. The borders of cysts were mostly well defined. The interior of cysts contained echogenic particulate materials, septations, or fine echoes. At the 10th intercostal space, the ventral margin, size, thickness and angle of livers were higher (P<0.01), while the diameter of portal vein was lower (P<0.01) in sheep with liver cysts than control ones. Furthermore, at the 9th intercostal space, the circumference of the gall bladder was decreased in sheep with hepatic cysts (P<0.01). The sensitivity, specificity, and positive and negative predictive values of ultrasonography for diagnosis of hepatic hydatid cysts were 80 per cent and 100 per cent, and 100 per cent and 83 per cent, respectively.

Conclusions

Cystic echinococcosis is associated with a number of anatomical alterations in the liver tissues that can be easily recognised by ultrasound. Furthermore, ultrasonography alone or in combination with analysis of biochemical parameters reflecting liver function could be helpful for diagnosis of hepatic hydatid cysts in sheep.
Alterations in sclerostin protein in lesions of equine osteochondrosis
Authors: Power Jonathon , Hernandez Paula , Wardale John , Henson Frances M. D.
Published: June 2014

Osteochondrosis (OC) is a common and clinically important joint disease that occurs in many species, including humans, pigs, chickens and horses. It has been described as a focal failure of endochondral ossification (EO), but no cellular/molecular mechanisms are fully described that explain the cause of this condition. Recently a Wnt signalling inhibitor, sclerostin, has been described in osteoarthritic cartilage, where it has been proposed to protect damaged cartilage from degradation. Cartilage degradation is a key event in EO, thus, abnormalities of sclerostin in growth cartilage could, potentially, lead to a failure of EO and, thus, OC. The aim of this study was to describe the distribution of sclerostin protein in normal and OC growth cartilage.

Immunohistochemistry (IHC) was used to localise sclerostin protein in normal and OC growth cartilage. Growth cartilage was harvested from the distal femur of horses aged between 6 and 18 months. Cartilage was classified as normal or having lesions consistent with a diagnosis of early OC. IHC was used to identify sclerostin protein in cartilage sections. Sclerostin protein distribution was semiquantified using a grading system and shown to be upregulated throughout all three zones of cartilage in lesions of OC (IHC score 8.1 compared to IHC score of 0.88). These results indicate that sclerostin may be contributing to the development of OC lesions by inhibiting extracellular matrix remodelling or may reflect the response of damaged cartilage. Clearly, further work is required to fully characterise this observation but, with antisclerostin antibodies used to treat human osteoporosis, the possibility of development of a systemic treatment of OC remains a potential goal.
Serum fatty acid profiling within distinct lipid fractions provides a more robust indicator of insulin resistance in humans than total triglyceride and fatty acid profiles
Authors: Zulyniak Michael A.
Published: June 2014

The need to better predict the development of insulin resistance (IR) and type 2 diabetes (T2D) is necessary as the prevalence of T2D is projected to increase in Canada and cost Canadians ∼$18 billion by 2030. The International Diabetes Federation currently advises the use of total blood triglycerides (TGs) as a predictor for identifying individuals at risk of developing IR and T2D. However, it has been demonstrated that total TG levels do not reliably reflect IR across multiple ethnicities. This suggests that a more accurate marker of IR is required. Interestingly, recent evidence suggests that distinct fatty acids (FAs) in blood TGs can reflect an individual’s IR status more accurately than total TGs. It is therefore reasonable to postulate that an analysis of the FAs within TGs and other blood lipids could lead to the discovery of a more accurate marker of IR. Over the course of 3 studies, the following thesis aimed to demonstrate that distinct FAs within serum lipids are associated with markers of IR more robustly than total TGs or total FAs. First, a large cross-sectional cohort that comprised young adults was used to demonstrate the associations between individual serum FAs and markers of IR (e.g., fasting glucose). Second, a population of Caucasian men that varied in IR-risk was examined to demonstrate that specific serum FAs within TGs associate with markers of IR more strongly than total TG levels. Finally, a cohort of individuals was investigated to demonstrate the improved ability of phospholipid and TG FA profiles (compared with total FAs) to distinguish individuals varying in metabolic health. This thesis demonstrated that circulating FAs associate with markers of IR and that these associations vary between individuals of different sex and ethnicity. Furthermore, the findings of this thesis indicate that compared with total serum TGs, specific FAs within lipid fractions may provide a more accurate means to identify individuals at increased risk of developing IR and T2D. Collectively, this thesis encourages future investigations of FAs within serum lipid fractions to uncover an improved method for identifying individuals at risk of IR and T2D.