bluuebunny/crossref_metadata_2025 huggingface dataset:
Improved Sensitivity for Molecular Detection of Bacterial and Candida Infections in Blood
Authors: Bacconi Andrea , Richmond Gregory S. , Baroldi Michelle A. , Laffler Thomas G. , Blyn Lawrence B. , Carolan Heather E. , Frinder Mark R. , Toleno Donna M. , Metzgar David , Gutierrez Jose R. , Massire Christian , Rounds Megan , Kennel Natalie J. , Rothman Richard E. , Peterson Stephen , Carroll Karen C. , Wakefield Teresa , Ecker David J. , Sampath Rangarajan
Published: June 2014

The rapid identification of bacteria and fungi directly from the blood of patients with suspected bloodstream infections aids in diagnosis and guides treatment decisions. The development of an automated, rapid, and sensitive molecular technology capable of detecting the diverse agents of such infections at low titers has been challenging, due in part to the high background of genomic DNA in blood. PCR followed by electrospray ionization mass spectrometry (PCR/ESI-MS) allows for the rapid and accurate identification of microorganisms but with a sensitivity of about 50% compared to that of culture when using 1-ml whole-blood specimens. Here, we describe a new integrated specimen preparation technology that substantially improves the sensitivity of PCR/ESI-MS analysis. An efficient lysis method and automated DNA purification system were designed for processing 5 ml of whole blood. In addition, PCR amplification formulations were optimized to tolerate high levels of human DNA. An analysis of 331 specimens collected from patients with suspected bloodstream infections resulted in 35 PCR/ESI-MS-positive specimens (10.6%) compared to 18 positive by culture (5.4%). PCR/ESI-MS was 83% sensitive and 94% specific compared to culture. Replicate PCR/ESI-MS testing from a second aliquot of the PCR/ESI-MS-positive/culture-negative specimens corroborated the initial findings in most cases, resulting in increased sensitivity (91%) and specificity (99%) when confirmed detections were considered true positives. The integrated solution described here has the potential to provide rapid detection and identification of organisms responsible for bloodstream infections.
Population Dynamics of an Acinetobacter baumannii Clonal Complex during Colonization of Patients
Authors: Wen Hanchun , Wang Ke , Liu Yang , Tay Martin , Lauro Federico M. , Huang Hong , Wu Huayu , Liang Hongjie , Ding Yichen , Givskov Michael , Chen Yiqiang , Yang Liang
Published: June 2014

Acinetobacter baumannii
has emerged as one of the leading pathogens causing hospital-acquired infection. The success of
A. baumannii
as a pathogen has to a large extent been attributed to its capacity to remodel its genome. Several major epidemic clonal complexes of
A. baumannii
spread across different health care facilities around the world, each of which contains a subset of diversified strains. However, little is known about the population dynamics during colonization of
A. baumannii
within hosts. Here, whole-genome sequencing was used to analyze population dynamics of
A. baumannii
strains isolated from a group of patients at different time points as well as from different sites of a particular patient. Seven out of nine of the sampled
A. baumannii
strains belonged to the international clone II (CC92 clonal complex). While the
A. baumannii
strains were found to be stable in three patients, there was a change of
A. baumannii
strains in one patient. Comparative genomic analysis revealed that the accessory genome of these strains contained a large set of virulence-encoding genes and these virulence factors might play a role in determining population dynamics. Microscale genome modification has been revealed by analysis of single nucleotide polymorphisms (SNPs) between
A. baumannii
strains isolated from the same patient. Parallel evolutionary traits have been observed during genome diversification when
A. baumannii
colonize in different patients. Our study suggested that both antibiotic usage and host environment might impose selective forces that drive the rapid adaptive evolution in colonizing
A. baumannii
.
Whole-Genome Analysis of Exserohilum rostratum from an Outbreak of Fungal Meningitis and Other Infections
Authors: Litvintseva Anastasia P. , Hurst Steven , Gade Lalitha , Frace Michael A. , Hilsabeck Remy , Schupp James M. , Gillece John D. , Roe Chandler , Smith David , Keim Paul , Lockhart Shawn R. , Changayil Shankar , Weil M. Ryan , MacCannell Duncan R. , Brandt Mary E. , Engelthaler David M.
Published: June 2014

Exserohilum rostratum
was the cause of most cases of fungal meningitis and other infections associated with the injection of contaminated methylprednisolone acetate produced by the New England Compounding Center (NECC). Until this outbreak, very few human cases of
Exserohilum
infection had been reported, and very little was known about this dematiaceous fungus, which usually infects plants. Here, we report using whole-genome sequencing (WGS) for the detection of single nucleotide polymorphisms (SNPs) and phylogenetic analysis to investigate the molecular origin of the outbreak using 22 isolates of
E. rostratum
retrieved from 19 case patients with meningitis or epidural/spinal abscesses, 6 isolates from contaminated NECC vials, and 7 isolates unrelated to the outbreak. Our analysis indicates that all 28 isolates associated with the outbreak had nearly identical genomes of 33.8 Mb. A total of 8 SNPs were detected among the outbreak genomes, with no more than 2 SNPs separating any 2 of the 28 genomes. The outbreak genomes were separated from the next most closely related control strain by ∼136,000 SNPs. We also observed significant genomic variability among strains unrelated to the outbreak, which may suggest the possibility of cryptic speciation in
E. rostratum
.
Detection of Methicillin-Resistant Coagulase-Negative Staphylococci by the Vitek 2 System
Authors: Johnson Kristen N. , Andreacchio Kathleen , Edelstein Paul H.
Published: June 2014

The accurate performance of the Vitek 2 GP67 card for detecting methicillin-resistant coagulase-negative staphylococci (CoNS) is not known. We prospectively determined the ability of the Vitek 2 GP67 card to accurately detect methicillin-resistant CoNS, with
mecA
PCR results used as the gold standard for a 4-month period in 2012. Included in the study were 240 consecutively collected nonduplicate CoNS isolates. Cefoxitin susceptibility by disk diffusion testing was determined for all isolates. We found that the three tested systems, Vitek 2 oxacillin and cefoxitin testing and cefoxitin disk susceptibility testing, lacked specificity and, in some cases, sensitivity for detecting methicillin resistance. The Vitek 2 oxacillin and cefoxitin tests had very major error rates of 4% and 8%, respectively, and major error rates of 38% and 26%, respectively. Disk cefoxitin testing gave the best performance, with very major and major error rates of 2% and 24%, respectively. The test performances were species dependent, with the greatest errors found for
Staphylococcus saprophyticus
. While the 2014 CLSI guidelines recommend reporting isolates that test resistant by the oxacillin MIC or cefoxitin disk test as oxacillin resistant, following such guidelines produces erroneous results, depending on the test method and bacterial species tested. Vitek 2 cefoxitin testing is not an adequate substitute for cefoxitin disk testing. For critical-source isolates,
mecA
PCR, rather than Vitek 2 or cefoxitin disk testing, is required for optimal antimicrobial therapy.
Rothia Bacteremia: a 10-Year Experience at Mayo Clinic, Rochester, Minnesota
Authors: Ramanan Poornima , Barreto Jason N. , Osmon Douglas R. , Tosh Pritish K.
Published: June 2014

Rothia
spp. are Gram-positive cocco-bacilli that cause a wide range of serious infections, especially in immunocompromised hosts. Risk factors for
Rothia mucilaginosa
(previously known as
Stomatococcus mucilaginosus
) bacteremia include prolonged and profound neutropenia, malignancy, and an indwelling vascular foreign body. Here, we describe 67 adults at the Mayo Clinic in Rochester, MN, from 2002 to 2012 with blood cultures positive for
Rothia
. Twenty-five of these patients had multiple positive blood cultures, indicating true clinical infection. Among these, 88% (22/25) were neutropenic, and 76% (19/25) had leukemia. Common sources of bacteremia were presumed gut translocation, mucositis, and catheter-related infection. One patient died with
Rothia
infection. Neutropenic patients were less likely to have a single positive blood culture than were nonneutropenic patients. Antimicrobial susceptibility testing was performed on 21% of the isolates. All of the tested isolates were susceptible to vancomycin and most beta-lactams; however, four of six tested isolates were resistant to oxacillin. There was no difference between the neutropenic and nonneutropenic patients in need of intensive care unit care, mortality, or attributable mortality.
Cluster of Escherichia coli Isolates Producing a Plasmid-Mediated OXA-48 β-Lactamase in a Spanish Hospital in 2012
Authors: Fernández Javier , Montero Ignacio , Fleites Ana , Rodicio M. Rosario
Published: June 2014

Three unrelated sequence type 131 (ST131), ST58, and ST83
Escherichia coli
isolates with low-level resistance to imipenem and resistance to ertapenem were recovered in a Spanish hospital from July to October 2012. They were positive for
bla
OXA-48
carried by an IncL/M conjugative plasmid, which may have been acquired from
Klebsiella pneumoniae
.
Development of Two Molecular Approaches for Differentiation of Clinically Relevant Yeast Species Closely Related to Candida guilliermondii and Candida famata
Authors: Feng Xiaobo , Wu Jingsong , Ling Bo , Yang Xianwei , Liao Wanqing , Pan Weihua , Yao Zhirong
Published: June 2014

The emerging pathogens
Candida palmioleophila
,
Candida fermentati
, and
Debaryomyces nepalensis
are often misidentified as
Candida guilliermondii
or
Candida famata
in the clinical laboratory. Due to the significant differences in antifungal susceptibilities and epidemiologies among these closely related species, a lot of studies have focused on the identification of these emerging yeast species in clinical specimens. Nevertheless, limited tools are currently available for their discrimination. Here, two new molecular approaches were established to distinguish these closely related species. The first approach differentiates these species by use of restriction fragment length polymorphism analysis of partial internal transcribed spacer 2 (ITS2) and large subunit ribosomal DNA with the enzymes BsaHI and XbaI in a double digestion. The second method involves a multiplex PCR based on the intron size differences of
RPL18
, a gene coding for a protein component of the large (60S) ribosomal subunit, and species-specific amplification. These two methods worked well in differentiation of these closely related yeast species and have the potential to serve as effective molecular tools suitable for laboratory diagnoses and epidemiological studies.
Isolation of West Nile Virus from Urine Samples of Patients with Acute Infection
Authors: Barzon Luisa , Pacenti Monia , Franchin Elisa , Squarzon Laura , Sinigaglia Alessandro , Ulbert Sebastian , Cusinato Riccardo , Palù Giorgio
Published: June 2014

This study demonstrated that West Nile virus (WNV) excreted in the urine of patients with acute infection can be isolated in cell cultures. In addition, the protocols for WNV isolation from urine samples were standardized, and factors that may affect the efficiency of WNV isolation were identified.
Association of lifestyle factors and suboptimal health status: a cross-sectional study of Chinese students
Authors: Bi Jianlu , Huang Ying , Xiao Ya , Cheng Jingru , Li Fei , Wang Tian , Chen Jieyu , Wu Liuguo , Liu Yanyan , Luo Ren , Zhao Xiaoshan
Published: June 2014

Objectives

Suboptimal health status (SHS) is considered to be an intermediate status between disease and health, and is characterised by a decline in vitality, in physiological function and in the capacity for adaptation. Although the incidence of SHS is high, the underlying causes remain unclear. Lifestyle is one of the most important factors affecting health status; however, the relationship between SHS and lifestyle has not been elucidated.

Design

Cross-sectional survey.

Setting

A questionnaire, based on ‘Health Promoting Lifestyle Profile-II (HPLP-II)’ and ‘Sub-Health Measurement Scale V1.0 (SHMS V1.0)’, was sent to four colleges in four districts (Guangzhou, Foshan, Zhanjiang and Shaoguan) of China between May and July 2013.

Participants

A total of 12 429 questionnaires were distributed during the study period, and 11 144 completed responses were received.

Results

The prevalence rates for the ‘healthy’, ‘SHS’ and ‘disease’ groups of respondents (students) were 22.81% (2542), 55.9% (6234) and 21.25% (2368), respectively. Most of the students reported a ‘moderate’ or ‘good’ lifestyle. There were significant differences in lifestyle and health status between the two genders. It was notable that health status was significantly positively correlated with lifestyle (r=0.563). For every dimension of the HPLP-II model, the mean values were lower for those participants who reported as ‘SHS’ or ‘disease’ than for those who reported that they were ‘healthy’. The individual dimensions of the HPLP-II model, including ‘spiritual growth’, ‘health responsibility’, ‘physical activity’, ‘interpersonal relations’ and ‘stress management’ were all related to SHS.

Conclusions

Health status is significantly positively correlated with lifestyle. Poor lifestyle is a risk factor for SHS. Conversely, adopting a healthier lifestyle can improve SHS.

Trial registration number

ChiCTR-OCH-12002317.
Lifestyle risk factors for invasive pneumococcal disease: a systematic review
Authors: Cruickshank Helen C , Jefferies Johanna M , Clarke Stuart C
Published: June 2014

Objective

To systematically review the literature for evidence of smoking and alcohol intake as independent risk factors for invasive pneumococcal disease (IPD).

Design

Systematic review.

Methods

MEDLINE (1946—May 2012) and EMBASE (1947—May 2012) were searched for studies investigating alcohol or smoking as risk factors for acquiring IPD and which reported results as relative risk. Studies conducted exclusively in clinical risk groups, those assessing risk factors for outcomes other than acquisition of IPD and studies describing risk factors without quantifying a relative risk were excluded.

Results

Seven observational studies were identified and reviewed; owing to the heterogeneity of study design, meta-analysis was not attempted. Five of six studies investigating smoking reported an increased risk of IPD in the range 2.2–4.1. Four of the six studies investigating alcohol intake reported a significant increased risk for IPD ranging from 2.9 to 11.4, while one reported a significant protective effect.

Conclusions

Overall, these observational data suggest that smoking and alcohol misuse may increase the risk of IPD in adults, but the magnitude of this risk remains unclear and should be explored with further research. The findings of this review will contribute to the debate on whether pneumococcal vaccine should be offered to smokers and people who misuse alcohol in addition to other clinically defined risk groups.
Urgent off-label use of the pipeline flow diverter stent in selected ischemic cerebrovascular conditions: thrombotic segments and tortuous arteries
Authors: Cohen José E , Gomori J Moshe , Rajz Gustavo , Itshayek Eyal , Eichel Roni , Leker Ronen R
Published: June 2014

Objective

Flow diverter stents were originally designed for the endovascular management of certain types of cerebral aneurysms; however, these devices present characteristics that make them more suitable that regular carotid stents or neurostents for the management of selected ischemic cerebrovascular conditions.

Methods

Eight patients with steno-occlusive disease of the internal carotid (ICA) or vertebral (VA) arteries underwent endovascular reconstruction by means of flow diverter stent implant at our center. Five patients presented with ICA steno-occlusive lesions that involved tortuous segments not amenable to regular carotid stent placement and three patients presented with severe and complex proximal VA dissections.

Results

In all cases the procedures were considered technically successful. Flow diverter stent implant allowed recanalization of the treated vessels (stenosis of 89±10.5% was improved to 26±13%) without procedure related complications. At the 3 month clinical and radiological follow-up, patients either improved or remained stable, and showed stent patency. One patient presented with asymptomatic occlusion of the revascularized artery at 13 months, emphasizing the need for prolonged antiplatelet therapy.

Conclusions

This preliminary series of patients with high risk steno-occlusive lesions affecting tortuous arterial segments or presenting with heavy thrombotic load managed by the implant of flow diverter stents shows that this approach is feasible, safe, and effective in achieving arterial recanalization. Further studies will elucidate the role of this technique in ischemic cerebrovascular settings.
Technical limitations of dual-energy CT in neuroradiology: 30-month institutional experience and review of literature
Authors: Dinkel Julien , Khalilzadeh Omid , Phan Catherine M , Goenka Ajit H , Yoo Albert J , Hirsch Joshua A , Gupta Rajiv
Published: June 2014

Background

Dual-energy CT (DECT) has been shown to be a useful modality in neuroradiology.

Objective

To assess failure modes and limitations of DECT in different neuroimaging applications.

Patients and methods

Dual-source DECT scans were performed in 72 patients over 30 months to differentiate contrast agent staining or extravasation from intracranial hemorrhage (ICH) (n=40); to differentiate calcium from ICH (n=2); for metal-artifact reduction (n=5); and for angiographic assessment (n=25). A three-material decomposition algorithm was used to obtain virtual non-contrast (VNC) and iodine (or calcium) overlay images. Images were analyzed in consensus by two board-certified radiologists to determine the success of the algorithm and to assess confounding factors. Furthermore, a dilution experiment using cylinders containing defined heparinized swine blood, normal saline, and selected iodine concentrations was conducted to assess other possible confounding factors.

Results

Dual-energy analysis was successful in 65 (90.2%) patients. However, the algorithm failed when images were affected by beam hardening (n=3, 4.2%), the presence of a fourth material (parenchymal calcification) (n=3, 4.2%), or motion (n=1, 1.4%). In the dilution experiment, a saturation effect was seen at high iodine concentrations (≥37 mg/ml). VNC and iodine overlay images were not reliable above this concentration, and beam-hardening artifacts were noted.

Conclusions

DECT material decomposition is usually successful in neuroradiology. However, it can only distinguish up to three preselected materials. A fourth material such as parenchymal calcium may confound the analysis. Artifacts such as beam hardening, metallic streak, or saturation effect can also impair material decomposition.
Mentorship for newly appointed consultants: what makes it work?
Authors: Harrison Reema , Anderson John , Laloë Pierre-Antoine , Santillo Marta , Lawton Rebecca , Wright John
Published: June 2014

Background

Mentorship has been identified as a beneficial practice for doctors and may be particularly valuable for newly appointed consultants. It is associated with a number of potential clinical and non-clinical gains, such as enhanced job satisfaction and well-being. Despite strong support, many formalised schemes fail to launch or gain momentum. Research to date has largely focused on the gains associated with mentorship but has lacked study of the factors that facilitate uptake and maintenance of mentoring relationships by physicians.

Objectives

To explore perceptions of mentorship, the extent to which UK doctors appear to value mentorship and factors that may contribute to its successful use.

Design

Qualitative, descriptive, multi-centre study.

Sample

30 doctors including registrars, those newly appointed to consultant grade, senior doctors and medical leaders from nine hospitals in the north of England.

Method

Semistructured individual interviews were undertaken between August and December 2013.

Results

Findings revealed a demand for mentorship for new consultants, with widely recognised benefits associated with its use. Several factors were identified as critical to successful mentorship relationships, including consistent understanding and expectations of mentorship between mentee and mentor, positive prior experiences, a suitable match between mentee and mentor, making time for people to act as mentors and the ensuring that mentors can meet a diverse and changing set of needs.

Conclusions

Mentorship for newly appointed consultants is valued, but current models of mentorship may suffer from rigid structures, mismatched expectations of participants and the absence of a culture of mentorship from training into practice. A social network approach, in which doctors have the opportunity to engage with a range of mentors through informal and naturally occurring relationships, may be one way to encourage successful and sustained mentoring relationships among doctors. An organisational culture in which mentorship is permitted and is the norm may enable such approaches to be widely adopted.
Plasmon-enhanced polarization-selective filter based on multiple holes array filled with nonlinear medium
Authors: Dai Jin , Wang Shihong , Song Gang , Yu Li , Wang Lulu , Xiao Jinghua
Published: June 2014

In this paper, a plasmon-enhanced polarization-selective filter is theoretically investigated in a structure composed of multiple holes array by filling it with nonlinear medium. The system combines the characteristics of selectable wavelength, enhanced transmission, polarization separation and output control by the intensity of incident light. As the incident light intensity approaches terawatt range, the optical bistability phenomenon appears only in y-polarization for one mode, while it appears in both x- and y-polarizations for the other mode, which is controlled by the coefficient of finesse F caused by the mirror reflectivity. Our findings demonstrate a feasible method for constructing nanoscale optical logical gates, filters, and all-optical switches; this method might be helpful for integrated optical circuits and on-chip optical interconnects.
On the modification of nuclear chronometry methods in astrophysics and geophysics induced by excited states of alpha radioactive nuclei and gamma emission
Authors: Dolinska M. E. , Doroshko N. L. , Olkhovsky V. S.
Published: June 2014

In practically all methods of nuclear chronometry known till now, were the lifetimes of only fundamental states for decaying α-radioactive nuclei usually taken into account. But in the processes of nuclear synthesis in stars and under the influence of the constant cosmic radiation on the surfaces of planets, also the excited α-radioactive nuclei appear. Between them, there are the states with the excited α-particles inside the parent nuclei. They have much smaller lifetimes relative to the Geiger and Nutall law. And inside the large masses of stellar, terrestrial and meteoric substances, the transitions between different excited radioactive nuclei are accompanied by infinite chains of the γ-radiations with the subsequent γ-absorptions, the further γ-radiations etc. We must describe the α-decay evolution, considering such excited states and multiple γ-radiations and γ-absorptions inside stars and also under the influence of the cosmic radiation on the earth surface. We present the quantum-mechanical approach, which is based on the generalized Krylov–Fock theorem. Some simple estimations are presented. They give rise to the conclusion that the usual (non-corrected) "nuclear clocks" do not really indicate the realistic values but the upper limits of the durations of the α-decay stellar and planet processes.
Age, aerobic fitness, and cerebral perfusion during exercise: role of carbon dioxide
Authors: Flück Daniela , Braz Igor D. , Keiser Stefanie , Hüppin Fabienne , Haider Thomas , Hilty Matthias P. , Fisher James P. , Lundby Carsten
Published: June 2014

Middle cerebral artery mean velocity (MCAvmean) is attenuated with increasing age both at rest and during exercise. The aim of this study was to determine the influence of the age-dependent reduction in arterial Pco2 (PaCO2) and physical fitness herein. We administered supplemental CO2 (CO2 trial) or no additional gas (control trial) to the inspired air in a blinded and randomized manner, and assessed middle cerebral artery mean flow velocity during graded exercise in 1) 21 young [Y; age 24 ± 3 yr (±SD)] volunteers of whom 11 were trained (YT) and 10 considered untrained (YUT), and 2) 17 old (O; 66 ± 4 yr) volunteers of whom 8 and 9 were considered trained (OT) and untrained (OUT), respectively. A resting hypercapnic reactivity test was also performed. MCAvmean and PaCO2 were lower in O [44.9 ± 3.1 cm/s and 30 ± 1 mmHg (±SE)] compared with Y (59.3 ± 2.3 cm/s and 34 ± 1 mmHg, P < 0.01) at rest, independent of aerobic fitness level. The age-related decreases in MCAvmean and PaCO2 persisted during exercise. Supplemental CO2 reduced the age-associated decline in MCAvmean by 50%, suggesting that PaCO2 is a major component in the decline. On the other hand, relative hypercapnic reactivity was neither influenced by age ( P = 0.46) nor aerobic fitness ( P = 0.36). Although supplemental CO2 attenuated exercise-induced reduction in cerebral oxygenation (near-infrared spectroscopy), this did not influence exercise performance. In conclusion, PaCO2 contributes to the age-associated decline in MCAvmean at rest and during exercise; however exercise capacity did not diminish this age effect.
The atypical structure and function of newborn arterial endothelium is mediated by Rho/Rho kinase signaling
Authors: Flavahan Sheila , Flavahan Nicholas A.
Published: June 2014

Endothelium of fetal or newborn arteries is atypical, displaying actin stress fibers and reduced nitric oxide (NO)-mediated dilatation. This study tested the hypothesis that Rho/Rho kinase signaling, which promotes endothelial stress fibers and inhibits endothelial dilatation, contributed to this phenotype. Carotid arteries were isolated from newborn [ postnatal day 1 (P1)], P7, and P21 mice. Endothelial dilatation to acetylcholine (pressure myograph) was minimal at P1, increased at P7, and further increased at P21. Inhibition of Rho (C3 transferase) or Rho kinase (Y27632, fasudil) significantly increased dilatation to acetylcholine in P1 arteries but had no effect in P7 or P21 arteries. After inhibition of NO synthase ( NG-nitro-l-arginine methyl ester), Rho kinase inhibition no longer increased acetylcholine responses in P1 arteries. Rho kinase inhibition did not affect dilatation to the NO donor DEA-NONOate. The endothelial actin cytoskeleton was labeled with phalloidin and visualized by laser-scanning microscopy. In P1 arteries, the endothelium had prominent transcytoplasmic stress fibers, whereas in P7 and P21 arteries, the actin fibers had a significantly reduced intensity and were restricted to cell borders. Phosphorylation of myosin light chains, a Rho kinase substrate, was highest in P1 endothelium and significantly reduced in P7 and P21 endothelium (laser-scanning microscopy). In P1 arteries, inhibition of Rho (C3 transferase) or Rho kinase (Y27632) significantly reduced the intensity of actin fibers, which were restricted to cell borders. Similarly, in P1 arteries, Rho inhibition significantly reduced endothelial levels of phosphorylated myosin light chains. These results indicate that the atypical function and morphology of newborn endothelium is mediated by Rho/Rho kinase signaling.
PKC-mediated toxicity of elevated glucose concentration on cardiomyocyte function
Authors: Sims Mark W. , Winter James , Brennan Sean , Norman Robert I. , André Ng G. , Squire Iain B. , Rainbow Richard D.
Published: June 2014

While it is well established that mortality risk after myocardial infarction (MI) increases in proportion to blood glucose concentration at the time of admission, it is unclear whether there is a direct, causal relationship. We investigated potential mechanisms by which increased blood glucose may exert cardiotoxicity. Using a Wistar rat or guinea-pig isolated cardiomyocyte model, we investigated the effects on cardiomyocyte function and electrical stability of alterations in extracellular glucose concentration. Contractile function studies using electric field stimulation (EFS), patch-clamp recording, and Ca2+ imaging were used to determine the effects of increased extracellular glucose concentration on cardiomyocyte function. Increasing glucose from 5 to 20 mM caused prolongation of the action potential and increased both basal Ca2+ and variability of the Ca2+ transient amplitude. Elevated extracellular glucose concentration also attenuated the protection afforded by ischemic preconditioning (IPC), as assessed using a simulated ischemia and reperfusion model. Inhibition of PKCα and β, using Gö6976 or specific inhibitor peptides, attenuated the detrimental effects of glucose and restored the cardioprotected phenotype to IPC cells. Increased glucose concentration did not attenuate the cardioprotective role of PKCε, but rather activation of PKCα and β masked its beneficial effect. Elevated extracellular glucose concentration exerts acute cardiotoxicity mediated via PKCα and β. Inhibition of these PKC isoenzymes abolishes the cardiotoxic effects and restores IPC-mediated cardioprotection. These data support a direct link between hyperglycemia and adverse outcome after MI. Cardiac-specific PKCα and β inhibition may be of clinical benefit in this setting.
Tongxinluo inhibits vascular inflammation and neointimal hyperplasia through blockade of the positive feedback loop between miR-155 and TNF-α
Authors: Zhang Ruo-nan , Zheng Bin , Li Li-min , Zhang Jing , Zhang Xin-hua , Wen Jin-kun
Published: June 2014

Tongxinluo (TXL), a traditional Chinese medicine, has multiple vasoprotective effects, including anti-inflammation. MicroRNA-155 (miR-155) is involved in vascular inflammation and atherosclerosis. However, a direct relationship between TXL and miR-155 in the development of vascular inflammation and remodeling had not yet been shown. The objective of the present study was to investigate whether TXL exerts an inhibitory effect on the vascular inflammatory response and neointimal hyperplasia by regulating miR-155 expression. Using the carotid artery ligation model in mice, we have shown that TXL dose dependently inhibited neointimal formation and reduced the vascular inflammatory response by inhibiting inflammatory cytokine production and macrophage infiltration. miR-155 was induced by carotid artery ligation, and neointimal hyperplasia was strongly reduced in miR-155−/− mice. In contrast, miR-155 overexpression partly reversed the inhibitory effect of TXL on neointimal hyperplasia. In bone marrow-derived macrophages, miR-155 and TNF-α formed a positive feedback loop to promote the inflammatory response, which could be blocked by TXL. Furthermore, TXL increased Akt1 protein expression and phosphorylation in TNF-α-stimulated marrow-derived macrophages, and knockdown of Akt1 abrogated the TXL-induced suppression of miR-155. In conclusion, TXL inhibits the vascular inflammatory response and neointimal hyperplasia induced by carotid artery ligation in mice. Suppression of miR-155 expression mediated by Akt1 and blockade of the feedback loop between miR-155 and TNF-α are important pathways whereby TXL exerts its vasoprotective effects.
miR-210 promotes IPF fibroblast proliferation in response to hypoxia
Authors: Bodempudi Vidya , Hergert Polla , Smith Karen , Xia Hong , Herrera Jeremy , Peterson Mark , Khalil Wajahat , Kahm Judy , Bitterman Peter B. , Henke Craig A.
Published: June 2014

Idiopathic pulmonary fibrosis (IPF) is characterized by the relentless spread of fibroblasts from scarred alveoli into adjacent alveolar units, resulting in progressive hypoxia and death by asphyxiation. Although hypoxia is a prominent clinical feature of IPF, the role of hypoxia as a driver of the progressive fibrotic nature of the disease has not been explored. Here, we demonstrate that hypoxia robustly stimulates the proliferation of IPF fibroblasts. We found that miR-210 expression markedly increases in IPF fibroblasts in response to hypoxia and that knockdown of miR-210 decreases hypoxia-induced IPF fibroblast proliferation. Silencing hypoxia-inducible factor (HIF)-2α inhibits the hypoxia-mediated increase in miR-210 expression and blocks IPF fibroblast proliferation, indicating that HIF-2α is upstream of miR-210. We demonstrate that the miR-210 downstream target MNT is repressed in hypoxic IPF fibroblasts and that knockdown of miR-210 increases MNT expression. Overexpression of MNT inhibits hypoxia-induced IPF fibroblast proliferation. Together, these data indicate that hypoxia potently stimulates miR-210 expression via HIF-2α, and high miR-210 expression drives fibroblast proliferation by repressing the c-myc inhibitor, MNT. In situ analysis of IPF lung tissue demonstrates miR-210 expression in a similar distribution with HIF-2α and the hypoxic marker carbonic anhydrase-IX in cells within the IPF fibrotic reticulum. Our results raise the possibility that a pathological feed-forward loop exists in the IPF lung, in which hypoxia promotes IPF fibroblast proliferation via stimulation of miR-210 expression, which in turn worsens hypoxia.
Severity of neonatal hyperoxia determines structural and functional changes in developing mouse airway
Authors: Wang Hua , Jafri Anjum , Martin Richard J. , Nnanabu Jerry , Farver Carol , Prakash Y. S. , MacFarlane Peter M.
Published: June 2014

Wheezing is a major long-term respiratory morbidity in preterm infants with and without bronchopulmonary dysplasia. We hypothesized that mild vs. severe hyperoxic exposure in neonatal mice differentially affects airway smooth muscle hypertrophy and resultant airway reactivity. Newborn mice were exposed to 7 days of mild (40% oxygen) or severe (70% oxygen) hyperoxia vs. room air controls. Respiratory system resistance (Rrs), compliance (Crs), and airway reactivity were measured 14 days after oxygen exposure ended under ketamine/xylazine anesthesia. Baseline Rrs increased and Crs decreased in both treatment groups. Methacholine challenge dose dependently increased Rrs and decreased Crs in 40% oxygen-exposed mice, whereas Rrs and Crs responses were similar between 70% oxygen-exposed and normoxic controls. Airway smooth muscle thickness was increased in 40%- but not 70%-exposed mice, whereas collagen increased and both alveolar number and radial alveolar counts decreased after 40% and 70% oxygen. These data indicate that severity of hyperoxia may differentially affect structural and functional changes in the developing mouse airway that contribute to longer-term hyperreactivity. These findings may be important to our understanding of the complex role of neonatal supplemental oxygen therapy in postnatal development of airway responsiveness.
Resveratrol prevents hypoxia-induced arginase II expression and proliferation of human pulmonary artery smooth muscle cells via Akt-dependent signaling
Authors: Chen Bernadette , Xue Jianjing , Meng Xiaomei , Slutzky Jessica L. , Calvert Andrea E. , Chicoine Louis G.
Published: June 2014

Pulmonary artery smooth muscle cell (PASMC) proliferation plays a fundamental role in the vascular remodeling seen in pulmonary hypertensive diseases associated with hypoxia. Arginase II, an enzyme regulating the first step in polyamine and proline synthesis, has been shown to play a critical role in hypoxia-induced proliferation of human PASMC (hPASMC). In addition, there is evidence that patients with pulmonary hypertension have elevated levels of arginase in the vascular wall. Resveratrol, a natural polyphenol found in red wine and grape skins, has diverse biochemical and physiological actions including antiproliferative properties. Furthermore, resveratrol has been shown to attenuate right ventricular and pulmonary artery remodeling, both pathological components of pulmonary hypertension. The present studies tested the hypothesis that resveratrol would prevent hypoxia-induced pulmonary artery smooth muscle cell proliferation by inhibiting hypoxia-induced arginase II expression. Our data indicate that hypoxia-induced hPASMC proliferation is abrogated following treatment with resveratrol. In addition, the hypoxic induction of arginase II was directly attenuated by resveratrol treatment. Furthermore, we found that the inhibitory effect of resveratrol on arginase II in hPASMC was mediated through the PI3K-Akt signaling pathway. Supporting these in vitro findings, resveratrol normalized right ventricular hypertrophy in an in vivo neonatal rat model of chronic hypoxia-induced pulmonary hypertension. These novel data support the notion that resveratrol may be a potential therapeutic agent in pulmonary hypertension by preventing PASMC arginase II induction and proliferation.
Angiotensin II type 2 receptor ligand PD123319 attenuates hyperoxia-induced lung and heart injury at a low dose in newborn rats
Authors: Wagenaar Gerry T. M. , Sengers Rozemarijn M. A. , Laghmani El Houari , Chen Xueyu , Lindeboom Melissa P. H. A. , Roks Anton J. M. , Folkerts Gert , Walther Frans J.
Published: June 2014

Intervening in angiotensin (Ang)-II type 2 receptor (AT2) signaling may have therapeutic potential for bronchopulmonary dysplasia (BPD) by attenuating lung inflammation and preventing arterial hypertension (PAH)-induced right ventricular hypertrophy (RVH). We first investigated the role of AT2 inhibition with PD123319 (0.5 and 2 mg·kg−1·day−1) on the beneficial effect of AT2 agonist LP2–3 (5 μg/kg twice a day) on RVH in newborn rats with hyperoxia-induced BPD. Next we determined the cardiopulmonary effects of PD123319 (0.1 mg·kg−1·day−1) in two models: early treatment during continuous exposure to hyperoxia for 10 days and late treatment starting on day 6 in rat pups exposed postnatally to hyperoxia for 9 days, followed by a 9-day recovery period in room air. Parameters investigated included lung and heart histopathology, fibrin deposition, vascular leakage, and differential mRNA expression. Ten days of coadministration of LP2–3 and PD123319 abolished the beneficial effects of LP2–3 on RVH in experimental BPD. In the early treatment model PD123319 attenuated cardiopulmonary injury by reducing alveolar septal thickness, pulmonary influx of inflammatory cells, including macrophages and neutrophils, medial wall thickness of small arterioles, and extravascular collagen III deposition, and by preventing RVH. In the late treatment model PD123319 diminished PAH and RVH, demonstrating that PAH is reversible in the neonatal period. At high concentrations PD123319 blocks the beneficial effects of the AT2-agonist LP2–3 on RVH. At low concentrations PD123319 attenuates cardiopulmonary injury by reducing pulmonary inflammation and fibrosis and preventing PAH-induced RVH but does not affect alveolar and vascular development in newborn rats with experimental BPD.
Leptospirosis in Vellore: A Clinical and Serological Study
Authors: Vimala G. , Rani A. Mary Josephine , Gopal V. Raja
Published: June 2014

Leptospirosis is a severe spirochetal zoonosis in the world. It is considered an occupational disease of persons engaged in agriculture, sewage works, forestry, and animal slaughtering. A study was conducted with an objective of assessing the seroprevalence of leptospirosis in and around Vellore district, Tamil Nadu. The study was based on the signs and symptoms of the patients reporting fever in Vellore Municipal Clinic (Urban Malarial Scheme). Blood samples were collected from 129 patients. Animal studies were conducted from 24 rodents captured form the market place of the Vellore municipality. In the ZET (Zonal Entomological Team, Vellore) Laboratory the sera were examined by macroscopic slide agglutination test (MSAT). In the MAST, totally 10 positive leptospiral cases from human beings and 10 positive leptospiral cases from rats (Rattus rattusandRattus norvegicus) were found out. Then both positive cases of leptospiral vials were labeled, sealed, and sent to the Leptospirosis Research Laboratory, Madhavaram, Chennai, for further serovars examination. Among the various serovars identifiedautumnaliswas more prevalent. Our findings showed that the age groups between 15 and 55 years showed more susceptibility. Particularly the adults were more infected. The majority of seropositive individuals in the cases had only subclinical infection. Rodents were abundant and contributed to enzootic and endemic prevalence of leptospirosis.
An Integrative Analysis of the Tumorigenic Role of TAZ in Human Non–Small Cell Lung Cancer
Authors: Noguchi Satoshi , Saito Akira , Horie Masafumi , Mikami Yu , Suzuki Hiroshi I. , Morishita Yasuyuki , Ohshima Mitsuhiro , Abiko Yoshimitsu , Mattsson Johanna Sofia Margareta , König Helena , Lohr Miriam , Edlund Karolina , Botling Johan , Micke Patrick , Nagase Takahide
Published: June 2014

Purpose: TAZ, also known as WWTR1, has recently been suggested as an oncogene in non–small cell lung cancer (NSCLC). We investigated the clinical relevance of TAZ expression and its functional role in NSCLC tumorigenesis.

Experimental Design: We characterized TAZ at the DNA (n = 192), mRNA (n = 196), and protein levels (n = 345) in an NSCLC patient cohort. Gene expression analysis was complemented by a meta-analysis of public datasets (n = 1,382). The effects of TAZ on cell proliferation and cell cycle were analyzed in cell cultures and on tumor growth in mice. TAZ-dependent microarray-based expression profiles in NSCLC cells were combined with molecular profiles in human NSCLC tissues for in silico analysis.

Results: Higher TAZ mRNA and protein levels were associated with shorter patient survival. Transduction of TAZ enhanced cell proliferation and tumorigenesis in bronchial epithelial cells, whereas TAZ silencing suppressed cell proliferation and induced cell cycle arrest in NSCLC cells. Microarray and cell culture experiments showed that ErbB ligands (amphiregulin, epiregulin, and neuregulin 1) are downstream targets of TAZ. Our in silico analysis revealed a TAZ signature that substantiated the clinical impact of TAZ and confirmed its relationship to the epidermal growth factor receptor signaling pathway.

Conclusion: TAZ expression defines a clinically distinct subgroup of patients with NSCLC. ErbB ligands are suggested to mediate the effects of TAZ on lung cancer progression. Our findings emphasize the tumorigenic role of TAZ and may serve as the basis for new treatment strategies. Clin Cancer Res; 20(17); 4660–72. ©2014 AACR.
Flutamide and Biomarkers in Women at High Risk for Ovarian Cancer: Preclinical and Clinical Evidence
Authors: Gruessner Christine , Gruessner Angelika , Glaser Katherine , AbuShahin Nisreen , Zhou Yi , Laughren Cynthia , Wright Heather , Pinkerton Samantha , Yi Xiaofang , Stoffer Jha'nae , Azodi Masoud , Zheng Wenxin , Chambers Setsuko K.
Published: June 2014

We hypothesized that (i) preclinical biologic evidence exists for the role of androgens in ovarian cancer development and (ii) flutamide treatment of women at high risk for ovarian cancer may identify meaningful tissue biomarkers of androgen action and of ovarian cancer initiation. We showed that androgen ablation of male mice led to a 24-fold decrease in tumor burden from serous ovarian cells. In a phase II study, we studied the effect of preoperative flutamide treatment (125 mg/day × 6 weeks) in 12 women versus 47 controls, 47% with BRCA mutation. We analyzed immunohistochemical scores of candidate proteins CSF-1, CSF-1R, and ErbB4 in the epithelium and stroma of fallopian tube, ovary, and ovarian endosalpingiosis. Flutamide decreased the levels, notably, of CSF-1 and ErbB4 in ovarian stroma (P ≤ 0.0006) and ovarian endosalpingiosis (P ≤ 0.01), ErbB4 in ovarian epithelium (P = 0.006), and CSF-1R in ovarian endosalpingiosis (P = 0.009). Our logistic regression model clearly distinguished the flutamide patients from controls (P ≤ 0.0001). Our analysis of the precision of this model of CSF-1 and ErbB4 expression in ovarian stroma achieved 100% sensitivity and 97% specificity (AUC = 0.99). Thus, our data suggest that a short 6-week exposure of flutamide reversed elevated levels of CSF-1 and ErbB4 (both of which we had previously found correlated with high risk status). CSF-1 and ErbB4 in ovarian stroma led to a model with high predictive value for flutamide sensitivity. The effect of flutamide on marker expression in ovarian endosalpingiosis, previously associated with BRCA carrier status, suggests that ovarian endosalpingiosis may be a latent precursor to pelvic serous cancers. Cancer Prev Res; 7(9); 896–905. ©2014 AACR.
Are Hemodynamics Surrogate End Points in Pulmonary Arterial Hypertension?
Authors: Ventetuolo Corey E. , Gabler Nicole B. , Fritz Jason S. , Smith K. Akaya , Palevsky Harold I. , Klinger James R. , Halpern Scott D. , Kawut Steven M.
Published: June 2014

Background—

Although frequently assessed in trials and clinical practice, hemodynamic response to therapy has never been validated as a surrogate end point for clinical events in pulmonary arterial hypertension (PAH).

Methods and Results—

We performed a patient-level pooled analysis of 4 randomized, placebo-controlled trials to determine whether treatment-induced changes in hemodynamic values at 12 weeks accounted for the relationship between treatment assignment and the probability of early clinical events (death, lung transplantation, atrial septostomy, PAH hospitalization, withdrawal for clinical worsening, or escalation in PAH therapy). We included 1119 subjects with PAH. The median (interquartile range) age was 48 years (37–59 years), and 23% were men. A total of 656 patients (59%) received active therapy (101 [15%] iloprost, 118 [18%] sitaxsentan, 204 [31%] sildenafil, and 233 [36%] subcutaneous treprostinil). Active treatment significantly lowered right atrial pressure, mean pulmonary artery pressure, and pulmonary vascular resistance and increased cardiac output and index (
P
<0.01 for all). Changes in hemodynamic values (except for right atrial pressure and mean pulmonary artery pressure) were significantly associated with the risk of a clinical event (
P
<0.02 for all). Although active treatment approximately halved the odds of a clinical event compared with placebo (
P
<0.001), changes in hemodynamics accounted for only 1.2% to 13.9% of the overall treatment effect.

Conclusions—

Treatment-induced changes in hemodynamics at 12 weeks only partially explain the impact of therapy on the probability of early clinical events in PAH. These findings suggest that resting hemodynamics are not valid surrogate end points for short-term events in PAH clinical trials.
Theoretical model of fiber debonding and pull-out in unidirectional hybrid-fiber-reinforced brittle-matrix composites
Authors: Meng Qinghua , Wang Zhenqing
Published: June 2014

A theoretical model is developed to study the fiber debonding and pull-out in hybrid-fiber-reinforced brittle-matrix composites. By adopting the shear-lag model which includes the matrix shear deformation in the bonding region and friction in the debonding region, the relationship between the pull-out length and the debonding length of fiber is obtained by treating the interface debonding as a particular crack propagation problem along the interface. The interface debonding criterion for the hybrid-fiber-reinforced composites is obtained by applying the energy release rate relation in an interface debonding process. The analysis is applied to hybrid carbon/glass fiber-reinforced epoxy composites, and the theoretical results have a reasonable agreement with the experimental data. The hybrid effect is studied and the effect of material parameters is discussed.