bluuebunny/crossref_metadata_2025 huggingface dataset:
Escherichia coli Survival in, and Release from, White-Tailed Deer Feces
Authors: Guber Andrey K. , Fry Jessica , Ives Rebecca L. , Rose Joan B.
Published: December 2014

White-tailed deer are an important reservoir for pathogens that can contribute a large portion of microbial pollution in fragmented agricultural and forest landscapes. The scarcity of experimental data on survival of microorganisms in and release from deer feces makes prediction of their fate and transport less reliable and development of efficient strategies for environment protection more difficult. The goal of this study was to estimate parameters for modelingEscherichia colisurvival in and release from deer (Odocoileus virginianus) feces. Our objectives were as follows: (i) to measure survival ofE. coliin deer pellets at different temperatures, (ii) to measure kinetics ofE. colirelease from deer pellets at different rainfall intensities, and (iii) to estimate parameters of models describing survival and release of microorganisms from deer feces. Laboratory experiments were conducted to studyE. colisurvival in deer pellets at three temperatures and to estimate parameters of Chick's exponential model with temperature correction based on the Arrhenius equation. Kinetics ofE. colirelease from deer pellets were measured at two rainfall intensities and used to derive the parameters of Bradford-Schijven model of bacterial release. The results showed that parameters of the survival and release models obtained forE. coliin this study substantially differed from those obtained by using other source materials, e.g., feces of domestic animals and manures. This emphasizes the necessity of comprehensive studies of survival of naturally occurring populations of microorganisms in and release from wildlife animal feces in order to achieve better predictions of microbial fate and transport in fragmented agricultural and forest landscapes.
Resistance of Trichoplusia ni Populations Selected by Bacillus thuringiensis Sprays to Cotton Plants Expressing Pyramided Bacillus thuringiensis Toxins Cry1Ac and Cry2Ab
Authors: Kain Wendy , Song Xiaozhao , Janmaat Alida F. , Zhao Jian-Zhou , Myers Judith , Shelton Anthony M. , Wang Ping
Published: December 2014

Two populations of
Trichoplusia ni
that had developed resistance to
Bacillus thuringiensis
sprays (Bt sprays) in commercial greenhouse vegetable production were tested for resistance to Bt cotton (BollGard II) plants expressing pyramided Cry1Ac and Cry2Ab. The
T. ni
colonies resistant to
Bacillus thuringiensis
serovar kurstaki formulations were not only resistant to the Bt toxin Cry1Ac, as previously reported, but also had a high frequency of Cry2Ab-resistant alleles, exhibiting ca. 20% survival on BollGard II foliage. BollGard II-resistant
T. ni
strains were established by selection with BollGard II foliage to further remove Cry2Ab-sensitive alleles in the
T. ni
populations. The BollGard II-resistant strains showed incomplete resistance to BollGard II, with adjusted survival values of 0.50 to 0.78 after 7 days. The resistance to the dual-toxin cotton plants was conferred by two genetically independent resistance mechanisms: one to Cry1Ac and one to Cry2Ab. The 50% lethal concentration of Cry2Ab for the resistant strain was at least 1,467-fold that for the susceptible
T. ni
strain. The resistance to Cry2Ab in resistant
T. ni
was an autosomally inherited, incompletely recessive monogenic trait. Results from this study indicate that insect populations under selection by Bt sprays in agriculture can be resistant to multiple Bt toxins and may potentially confer resistance to multitoxin Bt crops.
Genome-Wide Identification of Genes Necessary for Biofilm Formation by Nosocomial Pathogen Stenotrophomonas maltophilia Reveals that Orphan Response Regulator FsnR Is a Critical Modulator
Authors: Kang Xiu-Min , Wang Fang-Fang , Zhang Huan , Zhang Qi , Qian Wei
Published: December 2014

Stenotrophomonas maltophilia
is a Gram-negative bacterial pathogen of increasing concern to human health. Most clinical isolates of
S. maltophilia
efficiently form biofilms on biotic and abiotic surfaces, making this bacterium resistant to a number of antibiotic treatments and therefore difficult to eliminate. To date, very few studies have investigated the molecular and regulatory mechanisms responsible for
S. maltophilia
biofilm formation. Here we constructed a random transposon insertion mutant library of
S. maltophilia
ATCC 13637 and screened 14,028 clones. A total of 46 nonredundant genes were identified. Mutants of these genes exhibited marked changes in biofilm formation, suggesting that multiple physiological pathways, including extracellular polysaccharide production, purine synthesis, transportation, and peptide and lipid synthesis, are involved in bacterial cell aggregation. Of these genes, 20 putatively contributed to flagellar biosynthesis, indicating a critical role for cell motility in
S. maltophilia
biofilm formation. Genetic and biochemical evidence demonstrated that an orphan response regulator, FsnR, activated transcription of at least two flagellum-associated operons by directly binding to their promoters. This regulatory protein plays a fundamental role in controlling flagellar assembly, cell motility, and biofilm formation. These results provide a genetic basis to systematically study biofilm formation of
S. maltophilia
.
Zoonotic Potential of Escherichia coli Isolates from Retail Chicken Meat Products and Eggs
Authors: Mitchell Natalie M. , Johnson James R. , Johnston Brian , Curtiss Roy , Mellata Melha
Published: December 2014

Chicken products are suspected as a source of extraintestinal pathogenic
Escherichia coli
(ExPEC), which causes diseases in humans. The zoonotic risk to humans from chicken-source
E. coli
is not fully elucidated. To clarify the zoonotic risk posed by ExPEC in chicken products and to fill existing knowledge gaps regarding ExPEC zoonosis, we evaluated the prevalence of ExPEC on shell eggs and compared virulence-associated phenotypes between ExPEC and non-ExPEC isolates from both chicken meat and eggs. The prevalence of ExPEC among egg-source isolates was low, i.e., 5/108 (4.7%). Based on combined genotypic and phenotypic screening results, multiple human and avian pathotypes were represented among the chicken-source ExPEC isolates, including avian-pathogenic
E. coli
(APEC), uropathogenic
E. coli
(UPEC), neonatal meningitis
E. coli
(NMEC), and sepsis-associated
E. coli
(SEPEC), as well as an undefined ExPEC group, which included isolates with fewer virulence factors than the APEC, UPEC, and NMEC isolates. These findings document a substantial prevalence of human-pathogenic ExPEC-associated genes and phenotypes among
E. coli
isolates from retail chicken products and identify key virulence traits that could be used for screening.
Genetic Mapping Reveals that Sinefungin Resistance in Toxoplasma gondii Is Controlled by a Putative Amino Acid Transporter Locus That Can Be Used as a Negative Selectable Marker
Authors: Behnke Michael S. , Khan Asis , Sibley L. David
Published: December 2014

Quantitative trait locus (QTL) mapping studies have been integral in identifying and understanding virulence mechanisms in the parasite
Toxoplasma gondii
. In this study, we interrogated a different phenotype by mapping sinefungin (SNF) resistance in the genetic cross between type 2 ME49-FUDR
r
and type 10 VAND-SNF
r
. The genetic map of this cross was generated by whole-genome sequencing of the progeny and subsequent identification of single nucleotide polymorphisms (SNPs) inherited from the parents. Based on this high-density genetic map, we were able to pinpoint the sinefungin resistance phenotype to one significant locus on chromosome IX. Within this locus, a single nonsynonymous SNP (nsSNP) resulting in an early stop codon in the TGVAND_290860 gene was identified, occurring only in the sinefungin-resistant progeny. Using CRISPR/CAS9, we were able to confirm that targeted disruption of TGVAND_290860 renders parasites sinefungin resistant. Because disruption of the
SNR1
gene confers resistance, we also show that it can be used as a negative selectable marker to insert either a positive drug selection cassette or a heterologous reporter. These data demonstrate the power of combining classical genetic mapping, whole-genome sequencing, and CRISPR-mediated gene disruption for combined forward and reverse genetic strategies in
T. gondii
.
Physical and neurodevelopmental outcomes in children with single-ventricle circulation
Authors: Davidson Joseph , Gringras Paul , Fairhurst Charlie , Simpson John
Published: December 2014

Objective

To investigate longer-term physical and neurodevelopmental outcomes of patients with hypoplastic left heart syndrome (HLHS) compared with other patients with functionally single-ventricle circulation surviving beyond the age of 10 years.

Design

A retrospective, observational study from a UK tertiary centre for paediatric cardiology.

Results

58 patients with HLHS and 44 non-HLHS patients with single-ventricle physiology were included. Subjective reduction in exercise tolerance was reported in 72% (95% CI 61% to 84%) of patients with HLHS and 45% (31% to 60%) non-HLHS patients. Compared with non-HLHS patients, educational concerns were reported more frequently in patients with HLHS, 41% (29% to 54%) vs 23% (10% to 35%), as was a diagnosis of a behaviour disorder (autism or attention deficit hyperactivity disorder) 12% (4% to 21%) vs 0%, and referral to other specialist services 67% (55% to 79%) vs 48% (33% to 63%).

Conclusions

Within a group of young people with complex congenital heart disease, those with HLHS are likely to have worse physical, psychological and educational outcomes.
Survival of patients with alcohol use disorders discharged from an emergency department: a population-based cohort study
Authors: Gunnarsdottir Anna Steinunn , Kristbjornsdottir Adalbjorg , Gudmundsdottir Ragnhildur , Gunnarsdottir Oddny Sigurborg , Rafnsson Vilhjalmur
Published: December 2014

Objectives

The aim was to study the cause-specific mortality of users of the emergency department (ED) who received a diagnosis of alcohol use disorder (AUD) in comparison with mortality of other users of the department.

Design

A population-based prospective cohort study.

Participants

All patients aged 18 years and above who were subsequently discharged home from the ED during the years 2002–2008. A total of 107 237 patients were followed by record linkage to a nationwide cause-of-death registry: 1210 patients with AUD as the main discharge diagnosis and 106 027 patients in the comparison group. HR and 95% CIs were calculated.

Setting

ED at Landspitali—the National University Hospital of Iceland, Reykjavik, Iceland. The hospital offers tertiary care and is the number one trauma centre and community hospital for the greater Reykjavik area. According to the population registry, 78% of the inhabitants of the area attended the ED during the study period.

Results

72 patients died in the AUD group and 4807 in the comparison group. The adjusted HR for all causes of death was 1.91 (95% CI 1.51 to 2.42). The HR for AUDs was 47.68 (95% CI 11.56 to 196.59) while for alcohol liver disease the HR was 19.06 (95% CI 6.07 to 59.87). The HR was also elevated for diseases of the circulatory system: HR 2.52 (95% CI 1.73 to 3.68); accidental poisoning: HR=13.64, (95% CI 3.98 to 46.73); suicide: HR=2.72 (95% CI 1.08 to 6.83); and event of undetermined intent: HR=10.89 (95% CI 4.53 to 26.16).

Conclusions

AUD as the discharge diagnosis at the ED, among patients who were not admitted to a hospital ward but discharged home, predicts increased mortality. As the results conclusively show the vulnerability of these patients, one can question whether their needs are adequately met at the ED.
A multistudy analysis investigating systematic differences in cardiovascular trial results between Europe and Asia
Authors: Hartley Louise C , Girling Alan J , Bowater Russell J , Lilford Richard J
Published: December 2014

Objective

To assess whether there are differences in the results of cardiovascular trials between Europe and Asia using data from an extensive collection of randomised controlled trials.

Study design and setting

All meta-analyses containing randomised controlled trials (RCT's) for the treatment or prevention of cardiovascular diseases were searched for in The Cochrane Library (2000–2008) and MEDLINE (2005–2008). Analysis was then conducted within and over each meta-analysis which satisfied given criteria. Separate estimates of treatment effect were calculated for Europe and Asia in each meta-analysis and then compared. Estimates of a common inter-continental difference over all meta-analyses were also calculated and meta-regression was performed. This was performed for both fatal and non-fatal end points.

Results

The literature search identified 59 meta-analyses that satisfied the inclusion criteria. After exclusion, the number of meta-analyses reporting greater effect sizes in Asia than in Europe was significantly more than would be expected by chance (fatal 12/14, p=0.013; non-fatal 23/32, p=0.020).

Conclusions

This study provides some evidence that for cardiovascular interventions treatment effect estimation differs between Europe and Asia, with respect to both fatal and non-fatal end points.
On this side of the bubble
Authors: Gaw Christopher E
Published: December 2014

I was told by many people that medical school would be a transformative period in my life. As I began my medical education, I started to grasp what this meant; medical school was not only an exhilarating academic experience, but a positive social one as well. However, my classmates and I soon realized that we were trapped in a bubble, one which separated the world of medicine from the world at large. Experiencing strain in some of my personal relationships, I tried to explore how the medical bubble could affect our lives not only as future physicians, but also as friends, family, and spouses. It is my hope that an awareness of the bubble will help those in medicine develop and maintain relationships with both their patients and those in their personal lives.
Cone-beam CT angiography (Dyna CT) for intraoperative localization of cerebral arteriovenous malformations
Authors: Srinivasan Visish M , Schafer Sebastian , Ghali Michael G Z , Arthur Adam , Duckworth Edward A M
Published: December 2014

Background

Arteriovenous malformations (AVMs) of the brain are commonly treated in multimodality fashion, with endovascular embolization followed by surgical extirpation being one of the most effective strategies. Modern endovascular suites enable rotational angiography, also known as cone-beam CT angiography (CBCT-A), using the full capability of modern C-arm digital angiography systems. This imaging modality offers a superior image quality to current options such as digital subtraction angiography, MRI, or CT angiography. Preoperative planning can be greatly aided by the resolution of angioarchitecture seen in CBCT-A images. Furthermore, these images can be used for intraoperative neuronavigation when integrated with widely used frameless stereotactic systems. The utility and outcome of the use of CBCT-A for preoperative planning and intraoperative localization of AVMs was evaluated.

Methods

A retrospective review was performed of 16 patients in which CBCT-A was performed, including radiological review and all clinical data.

Results

CBCT-A was successfully employed in all cases including those with (n=9) and without (n=7) rupture. Complete resection confirmed by postoperative angiography was achieved in all cases.

Conclusions

We present a novel application of CBCT-A in the treatment of AVMs, both for preoperative surgical planning and an intraoperative reference during neuronavigation.
A reassessment of the horned dinosaur Judiceratops tigris (Ornithischia: Ceratopsidae) from the Upper Cretaceous (Campanian) of Montana, USA
Authors: Campbell James A.
Published: December 2014

Judiceratops tigris is a recently described ceratopsid, collected from sediments of the Upper Cretaceous (middle Campanian) Judith River Formation (JRF) of northern Montana, USA. The current diagnosis for this taxon is tentative, as it is based on four fragmentary cranial specimens that have limited anatomical overlap. Although these four specimens were not found associated, they were all collected from the same localized area (Kennedy Coulee). New observations, interpretations, and reconstructions of J. tigris are presented in this study, based on the original assumption that these specimens represent the same taxon. Based on these findings, J. tigris had elongate postorbital horncores with an autapomorphic ovate (egg-shaped) cross section; squamosals with non-imbricated episquamosals, and an anterolaterally oriented anteriormost episquamosal; a wide medial parietal bar with an autapomorphic meniscus-shaped cross section; an anteroposteriorly wide posterior parietal bar, and, consequently, reduced parietal fenestrae; and at least four small, low-lying epiparietals on each side of the frill. A phylogenetic analysis incorporating the revised diagnosis of J. tigris supports the previous referral of this taxon to Chasmosaurinae, but missing anatomy prevents an understanding of how J. tigris is related to other chasmosaurines. Judiceratops tigris is retained here as a distinct taxon, and, hence, the oldest known chasmosaurine, but it has more in common with other chasmosaurines than was previously thought. Further fossil collecting in the JRF of Montana may produce more complete specimens of J. tigris and provide a means of testing the new reconstructions presented here.
Study of the boundary layer heat transfer of nanofluids over a stretching sheet: Passive control of nanoparticles at the surface
Authors: Ghalambaz M. , Izadpanahi E. , Noghrehabadi A. , Chamkha A.
Published: December 2014

The boundary layer heat and mass transfer of nanofluids over an isothermal stretching sheet is analyzed using a drift-flux model. The relative slip velocity between the nanoparticles and the base fluid is taken into account. The nanoparticles’ volume fractions at the surface of the sheet are considered to be adjusted passively. The thermal conductivity and the dynamic viscosity of the nanofluid are considered as functions of the local volume fraction of the nanoparticles. A non-dimensional parameter, heat transfer enhancement ratio, is introduced, which shows the alteration of the thermal convective coefficient of the nanofluid compared to the base fluid. The governing partial differential equations are reduced into a set of nonlinear ordinary differential equations using appropriate similarity transformations and then solved numerically using the fourth-order Runge–Kutta and Newton–Raphson methods along with the shooting technique. The effects of six non-dimensional parameters, namely, the Prandtl number of the base fluid Prbf, Lewis number Le, Brownian motion parameter Nb, thermophoresis parameter Nt, variable thermal conductivity parameter Nc and the variable viscosity parameter Nv, on the velocity, temperature, and concentration profiles as well as the reduced Nusselt number and the enhancement ratio are investigated. Finally, case studies for Al2O3 and Cu nanoparticles dispersed in water are performed. It is found that increases in the ambient values of the nanoparticles volume fraction cause decreases in both the dimensionless shear stress f″(0) and the reduced Nusselt number Nur. Furthermore, an augmentation of the ambient value of the volume fraction of nanoparticles results in an increase the heat transfer enhancement ratio hnf/hbf. Therefore, using nanoparticles produces heat transfer enhancement from the sheet.
Restoring redox balance enhances contractility in heart trabeculae from type 2 diabetic rats exposed to high glucose
Authors: Bhatt Niraj M. , Aon Miguel A. , Tocchetti Carlo G. , Shen Xiaoxu , Dey Swati , Ramirez-Correa Genaro , O′Rourke Brian , Gao Wei Dong , Cortassa Sonia
Published: December 2014

Hearts from type 2 diabetic (T2DM) subjects are chronically subjected to hyperglycemia and hyperlipidemia, both thought to contribute to oxidizing conditions and contractile dysfunction. How redox alterations and contractility interrelate, ultimately diminishing T2DM heart function, remains poorly understood. Herein we tested whether the fatty acid palmitate (Palm), in addition to its energetic contribution, rescues function by improving redox [glutathione (GSH), NAD(P)H, less oxidative stress] in T2DM rat heart trabeculae subjected to high glucose. Using cardiac trabeculae from Zucker Diabetic Fatty (ZDF) rats, we assessed the impact of low glucose (EG) and high glucose (HG), in absence or presence of Palm or insulin, on force development, energetics, and redox responses. We found that in EG ZDF and lean trabeculae displayed similar contractile work, yield of contractile work (Ycw), representing the ratio of force time integral over rate of O2 consumption. Conversely, HG had a negative impact on Ycw, whereas Palm, but not insulin, completely prevented contractile loss. This effect was associated with higher GSH, less oxidative stress, and augmented matrix GSH/thioredoxin (Trx) in ZDF mitochondria. Restoration of myocardial redox with GSH ethyl ester also rescued ZDF contractile function in HG, independently from Palm. These results support the idea that maintained redox balance, via increased GSH and Trx antioxidant activities to resist oxidative stress, is an essential protective response of the diabetic heart to keep contractile function.
Obesity superimposed on aging magnifies inflammation and delays the resolving response after myocardial infarction
Authors: Lopez Elizabeth F. , Kabarowski Janusz H. , Ingle Kevin A. , Kain Vasundhara , Barnes Stephen , Crossman David K. , Lindsey Merry L. , Halade Ganesh V.
Published: December 2014

Polyunsaturated fatty acid (PUFA) intake has increased over the last 100 yr, contributing to the current obesogenic environment. Obesity and aging are prominent risk factors for myocardial infarction (MI). How obesity interacts with aging to alter the post-MI response, however, is unclear. We tested the hypothesis that obesity in aging mice would impair the resolution of post-MI inflammation. PUFA diet (PUFA aging group) feeding to 12-mo-old C57BL/6J mice for 5 mo showed higher fat mass compared with standard lab chow (LC)-fed young (LC young group; 3–5 mo old) or aging alone control mice (LC aging group). LC young, LC aging, and PUFA aging mice were subjected to coronary artery ligation to induce MI. Despite similar infarct areas post-MI, plasma proteomic profiling revealed higher VCAM-1 in the PUFA aging group compared with LC young and LC aging groups, leading to increased neutrophil infiltration in the PUFA aging group ( P < 0.05). Macrophage inflammatory protein-1γ and CD40 were also increased at day 1, and myeloperoxidase remained elevated at day 5, an observation consistent with delayed wound healing in the PUFA aging group. Lipidomic analysis showed higher levels of arachidonic acid and 12( S)-hydroxyeicosatetraenoic acid at day 1 post-MI in the PUFA aging group compared with the LC aging group (all P < 0.05), thereby mediating neutrophil extravasation in the PUFA aging group. The inflammation-resolving enzymes 5-lipoxygenase, cyclooxygenase-2, and heme oxyegnase-1 were altered to delay wound healing post-MI in the PUFA aging group compared with LC young and LC aging groups. PUFA aging magnifies the post-MI inflammatory response and impairs the healing response by stimulating prolonged neutrophil trafficking and proinflammatory lipid mediators.
Overexpression of adenylyl cyclase type 5 (AC5) confers a proarrhythmic substrate to the heart
Authors: Zhao Zhenghang , Babu Gopal J. , Wen Hairuo , Fefelova Nadezhda , Gordan Richard , Sui Xiangzhen , Yan Lin , Vatner Dorothy E. , Vatner Stephen F. , Xie Lai-Hua
Published: December 2014

Inhibition of β-adrenergic receptor (β-AR) signaling is one of the most common therapeutic approaches for patients with arrhythmias. Adenylyl cyclase (AC) is the key enzyme responsible for transducing β-AR stimulation to increases in cAMP. The two major AC isoforms in the heart are types 5 and 6. Therefore, it is surprising that prior studies on overexpression of AC5 and AC6 in transgenic (Tg) mice have not examined mediation of arrhythmogenesis. Our goal was to examine the proarrhythmic substrate in AC5Tg hearts. Intracellular calcium ion (Ca2+i) was imaged in fluo-4 AM-loaded ventricular myocytes. The sarcoplasmic reticulum (SR) Ca2+ content, fractional Ca2+ release, and twitch Ca2+ transient were significantly higher in the AC5Tg vs. wild-type (WT) myocytes, indicating Ca2+ overload in AC5Tg myocytes. Action potential (AP) duration was significantly longer in AC5Tg than in WT myocytes. Additionally, AC5Tg myocytes developed spontaneous Ca2+ waves in a larger fraction compared with WT myocytes, particularly when cells were exposed to isoproterenol. The Ca2+ waves further induced afterdepolarizations and triggered APs. AC5Tg hearts had increased level of SERCA2a, oxidized Ca2+/calmodulin-dependent protein kinase II (CaMKII), and phosphorylation of ryanodine receptors (RyR) at the CaMKII site, especially after isoproterenol treatment. This was consistent with higher reactive oxygen species production in AC5Tg myocytes after isoproterenol treatment. Isoproterenol induced more severe arrhythmias in AC5Tg than in WT mice. We conclude that AC5 overexpression promotes arrhythmogenesis, by inducing SR Ca2+ overload and hyperactivation of RyR (phosphorylation by CaMKII), which in turn induces spontaneous Ca2+ waves and afterdepolarizations.
Diaphragmatic lymphatic vessel behavior during local skeletal muscle contraction
Authors: Moriondo Andrea , Solari Eleonora , Marcozzi Cristiana , Negrini Daniela
Published: December 2014

The mechanism through which the stresses developed in the diaphragmatic tissue during skeletal muscle contraction sustain local lymphatic function was studied in 10 deeply anesthetized, tracheotomized adult Wistar rats whose diaphragm was exposed after thoracotomy. To evaluate the direct effect of skeletal muscle contraction on the hydraulic intraluminal lymphatic pressures (Plymph) and lymphatic vessel geometry, the maximal contraction of diaphragmatic fibers adjacent to a lymphatic vessel was elicited by injection of 9.2 nl of 1 M KCl solution among diaphragmatic fibers while Plymph was recorded through micropuncture and vessel geometry via stereomicroscopy video recording. In lymphatics oriented perpendicularly to the longitudinal axis of muscle fibers and located at <300 μm from KCl injection, vessel diameter at maximal skeletal muscle contraction ( Dmc) decreased to 61.3 ± 1.4% of the precontraction value [resting diameter ( Drest)]; however, if injection was at >900 μm from the vessel, Dmc enlarged to 131.1 ± 2.3% of Drest. In vessels parallel to muscle fibers, Dmc increased to 122.8 ± 2.9% of Drest. During contraction, Plymph decreased as much as 22.5 ± 2.6 cmH2O in all submesothelial superficial vessels, whereas it increased by 10.7 ± 5.1 cmH2O in deeper vessels running perpendicular to contracting muscle fibers. Hence, the three-dimensional arrangement of the diaphragmatic lymphatic network seems to be finalized to efficiently exploit the stresses exerted by muscle fibers during the contracting inspiratory phase to promote lymph formation in superficial submesothelial lymphatics and its further propulsion in deeper intramuscular vessels.
Cardiac steatosis potentiates angiotensin II effects in the heart
Authors: Glenn Denis J. , Cardema Michelle C. , Ni Wei , Zhang Yan , Yeghiazarians Yerem , Grapov Dmitry , Fiehn Oliver , Gardner David G.
Published: December 2014

Lipid accumulation in the heart is associated with obesity and diabetes and may play an important role in the pathogenesis of heart failure. The renin-angiotensin system is also thought to contribute to cardiovascular morbidity in obese and diabetic patients. We hypothesized that the presence of lipid within the myocyte might potentiate the cardiomyopathic effects of ANG II in the cardiac diacylglycerol acyl transferase 1 (DGAT1) transgenic mouse model of myocyte steatosis. Treatment with ANG II resulted in a similar increase in blood pressure in both nontransgenic and DGAT1 transgenic mice. However, ANG II in DGAT1 transgenic mice resulted in a marked increase in interstitial fibrosis and a reduction in systolic function compared with nontransgenic littermates. Lipidomic analysis revealed that >20% of lipid species were significantly altered between nontransgenic and DGAT1 transgenic animals, whereas 3% were responsive to ANG II administration. ROS were also increased by ANG II in DGAT1 transgenic hearts. ANG II treatment resulted in increased expression of transforming growth factor (TGF)-β2and the type I TGF-β receptor as well as increased phosphorylation of Smad2 in DGAT1 transgenic hearts. Injection of neutralizing antibodies to TGF-β resulted in a reduction in fibrosis in DGAT1 transgenic hearts treated with ANG II. These results suggest that myocyte steatosis amplifies the fibrotic effects of ANG II through mechanisms that involve activation of TGF-β signaling and increased production of ROS.
l-Thyroxine promotes a proliferative airway smooth muscle phenotype in the presence of TGF-β1
Authors: Dekkers Bart G. J. , Naeimi Saeideh , Bos I. Sophie T. , Menzen Mark H. , Halayko Andrew J. , Hashjin Goudarz Sadeghi , Meurs Herman
Published: December 2014

Hypothyroidism may reduce, whereas hyperthyroidism may aggravate, asthma symptoms. The mechanisms underlying this relationship are largely unknown. Since thyroid hormones have central roles in cell growth and differentiation, we hypothesized that airway remodeling, in particular increased airway smooth muscle (ASM) mass, may be involved. To address this hypothesis, we investigated the effects of triiodothyronine (T3) and l-thyroxine (T4) in the absence and presence of the profibrotic transforming growth factor (TGF)-β1 on human ASM cell phenotype switching. T3 (1–100 nM) and T4 (1–100 nM) did not affect basal ASM proliferation. However, when combined with TGF-β1 (2 ng/ml), T4 synergistically increased the proliferative response, whereas only a minor effect was observed for T3. In line with a switch from a contractile to a proliferative ASM phenotype, T4 reduced the TGF-β1-induced contractile protein expression by ∼50%. Cotreatment with T3 reduced TGF-β1-induced contractile protein expression by ∼25%. The synergistic increase in proliferation was almost fully inhibited by the integrin αvβ3 antagonist tetrac (100 nM), whereas no significant effects of the thyroid receptor antagonist 1–850 (3 μM) were observed. Inhibition of MEK1/2, downstream of the integrin αvβ3, also inhibited the T4- and TGF-β1-induced proliferative responses. Collectively, the results indicate that T4, and to a lesser extent T3, promotes a proliferative ASM phenotype in the presence of TGF-β1, which is predominantly mediated by the membrane-bound T4 receptor αvβ3. These results indicate that thyroid hormones may enhance ASM remodeling in asthma, which could be of relevance for hyperthyroid patients with this disease.
LGL1 modulates proliferation, apoptosis, and migration of human fetal lung fibroblasts
Authors: Zhang Hui , Sweezey Neil B. , Kaplan Feige
Published: December 2014

Rapid growth and formation of new gas exchange units (alveogenesis) are hallmarks of the perinatal lung. Bronchopulmonary dysplasia (BPD), common in very premature infants, is characterized by premature arrest of alveogenesis. Mesenchymal cells (fibroblasts) regulate both lung branching and alveogenesis through mesenchymal-epithelial interactions. Temporal or spatial deficiency of late-gestation lung 1/cysteine-rich secretory protein LD2 (LGL1/CRISPLD2), expressed in and secreted by lung fibroblasts, can impair both lung branching and alveogenesis (LGL1 denotes late gestation lung 1 protein; LGL1 denotes the human gene; Lgl1 denotes the mouse/rat gene). Absence of Lgl1 is embryonic lethal. Lgl1 levels are dramatically reduced in oxygen toxicity rat models of BPD, and heterozygous Lgl1+/−mice exhibit features resembling human BPD. To explore the role of LGL1 in mesenchymal-epithelial interactions in developing lung, we developed a doxycycline (DOX)-inducible RNA-mediated LGL1 knockdown cellular model in human fetal lung fibroblasts (MRC5LGL1KD). We assessed the impact of LGL1 on cell proliferation, cell migration, apoptosis, and wound healing. DOX-induced MRC5LGL1KDsuppressed cell growth and increased apoptosis of annexin V+staining cells and caspase 3/7 activity. LGL1-conditioned medium increased migration of fetal rat primary lung epithelial cells and human airway epithelial cells. Impaired healing by MRC5LGL1KDcells of a wound model was attenuated by addition of LGL1-conditioned medium. Suppression of LGL1 was associated with dysregulation of extracellular matrix genes (downregulated MMP1, ColXVα1, and ELASTIN) and proapoptosis genes (upregulated BAD, BAK, CASP2, and TNFRSF1B) and inhibition of 44/42MAPK phosphorylation. Our findings define a role for LGL1 in fibroblast expansion and migration, epithelial cell migration, and mesenchymal-epithelial signaling, key processes in fetal lung development.
Relaxant effect of superimposed length oscillation on sensitized airway smooth muscle
Authors: Jo-Avila Miguel , Al-Jumaily Ahmed M. , Lu Jun
Published: December 2014

Asthma is associated with reductions in the airway lumen and breathing difficulties that are attributed to airway smooth muscles (ASM) hyperconstriction. Pharmaceutical bronchodilators such as salbutamol and isoproterenol are normally used to alleviate this constriction. Deep inspirations and tidal oscillations (TO) have also been reported to relax ASM in healthy airways with less response in asthmatics. Little information is available on the effect of other forms of oscillation on asthmatic airways. This study investigates the effect of length oscillations (LO), with amplitude 1 and 1.5% in the frequency range 5–20 Hz superimposed on breathing equivalent LO, on contracted ASM dissected from sensitized mice. These mice are believed to show some symptoms such as airway hyperreactivity similar to those associated with asthma in humans. In the frequency range used in this work, this study shows an increase in ASM relaxation of an average of 10% for 1.5% amplitude when compared with TO, ISO, or the combination of both. No similar finding is observed with 1% amplitude. This suggests that superimposed length oscillation acting over the interaction of myosin and actin during contraction may lead to temporal rearrangement and disturbance of the cross-bridge process in asthmatic airways.
Hypoxia-induced glucose-6-phosphate dehydrogenase overexpression and -activation in pulmonary artery smooth muscle cells: implication in pulmonary hypertension
Authors: Chettimada Sukrutha , Gupte Rakhee , Rawat Dhwajbahadur , Gebb Sarah A. , McMurtry Ivan F. , Gupte Sachin A.
Published: December 2014

Severe pulmonary hypertension is a debilitating disease with an alarmingly low 5-yr life expectancy. Hypoxia, one of the causes of pulmonary hypertension, elicits constriction and remodeling of the pulmonary arteries. We now know that pulmonary arterial remodeling is a consequence of hyperplasia and hypertrophy of pulmonary artery smooth muscle (PASM), endothelial, myofibroblast, and stem cells. However, our knowledge about the mechanisms that cause these cells to proliferate and hypertrophy in response to hypoxic stimuli is still incomplete, and, hence, the treatment for severe pulmonary arterial hypertension is inadequate. Here we demonstrate that the activity and expression of glucose-6-phosphate dehydrogenase (G6PD), the rate-limiting enzyme of the pentose phosphate pathway, are increased in hypoxic PASM cells and in lungs of chronic hypoxic rats. G6PD overexpression and -activation is stimulated by H2O2. Increased G6PD activity contributes to PASM cell proliferation by increasing Sp1 and hypoxia-inducible factor 1α (HIF-1α), which directs the cells to synthesize less contractile (myocardin and SM22α) and more proliferative (cyclin A and phospho-histone H3) proteins. G6PD inhibition with dehydroepiandrosterone increased myocardin expression in remodeled pulmonary arteries of moderate and severe pulmonary hypertensive rats. These observations suggest that altered glucose metabolism and G6PD overactivation play a key role in switching the PASM cells from the contractile to synthetic phenotype by increasing Sp1 and HIF-1α, which suppresses myocardin, a key cofactor that maintains smooth muscle cell in contractile state, and increasing hypoxia-induced PASM cell growth, and hence contribute to pulmonary arterial remodeling and pathogenesis of pulmonary hypertension.
Plasma vascular endothelial growth factor A and placental growth factor: novel biomarkers of pulmonary hypertension in congenital diaphragmatic hernia
Authors: Patel Neil , Moenkemeyer Florian , Germano Susie , Cheung Michael M. H.
Published: December 2014

Pulmonary hypertension (PH) due to abnormal pulmonary vascular development is an important determinant of illness severity in congenital diaphragmatic hernia (CDH). Vascular endothelial growth factor A (VEGFA) and placental growth factor (PLGF) may be important mediators of pulmonary vascular development in health and disease. This prospective study investigated the relationship between plasma VEGFA and PLGF and measures of pulmonary artery pressure, oxygenation, and cardiac function in CDH. A cohort of 10 infants with CDH consecutively admitted to a surgical neonatal intensive care unit (NICU) was recruited. Eighty serial plasma samples were obtained and analyzed by multiplex immunoassay to quantify VEGFA and PLGF. Concurrent assessment of pulmonary artery pressure (PAP) and cardiac function were made by echocardiography. Plasma VEGFA was higher and PLGF was lower in CDH compared with existing normative data. Combined plasma VEGFA:PLGF ratio correlated positively with measures of PAP, diastolic ventricular dysfunction, and oxygenation index. Nonsurvivors had higher VEGFA:PLGF ratio than survivors at days 3–4 of life and in the second week of life. These findings suggest that increased plasma VEGFA and reduced PLGF correlate with clinical severity of pulmonary vascular disease and may be associated with adverse outcome in CDH. This potential role for combined plasma VEGFA and PLGF in CDH as disease biomarkers, pathogenic mediators, and therapeutic targets merits further investigation.
ADAM-family metalloproteinases in lung inflammation: potential therapeutic targets
Authors: Dreymueller Daniela , Uhlig Stefan , Ludwig Andreas
Published: December 2014

Acute and chronic lung inflammation is driven and controlled by several endogenous mediators that undergo proteolytic conversion from surface-expressed proteins to soluble variants by a disintegrin and metalloproteinase (ADAM)-family members. TNF and epidermal growth factor receptor ligands are just some of the many substrates by which these proteases regulate inflammatory or regenerative processes in the lung. ADAM10 and ADAM17 are the most prominent members of this protease family. They are constitutively expressed in most lung cells and, as recent research has shown, are the pivotal shedding enzymes mediating acute lung inflammation in a cell-specific manner. ADAM17 promotes endothelial and epithelial permeability, transendothelial leukocyte migration, and inflammatory mediator production by smooth muscle and epithelial cells. ADAM10 is critical for leukocyte migration and alveolar leukocyte recruitment. ADAM10 also promotes allergic asthma by driving B cell responses. Additionally, ADAM10 acts as a receptor for Staphylococcus aureus ( S. aureus) α-toxin and is crucial for bacterial virulence. ADAM8, ADAM9, ADAM15, and ADAM33 are upregulated during acute or chronic lung inflammation, and recent functional or genetic analyses have linked them to disease development. Pharmacological inhibitors that allow us to locally or systemically target and differentiate ADAM-family members in the lung suppress acute and asthmatic inflammatory responses and S. aureus virulence. These promising results encourage further research to develop therapeutic strategies based on selected ADAMs. These studies need also to address the role of the ADAMs in repair and regeneration in the lung to identify further therapeutic opportunities and possible side effects.
Differential and opposing effects of imatinib on LPS- and ventilator-induced lung injury
Authors: Letsiou E. , Rizzo A. N. , Sammani S. , Naureckas P. , Jacobson J. R. , Garcia J. G. N. , Dudek S. M.
Published: December 2014

Endothelial dysfunction underlies the pathophysiology of vascular disorders such as acute lung injury (ALI) syndromes. Recent work has identified the Abl family kinases (c-Abl and Arg) as important regulators of endothelial cell (EC) barrier function and suggests that their inhibition by currently available pharmaceutical agents such as imatinib may be EC protective. Here we describe novel and differential effects of imatinib in regulating lung pathophysiology in two clinically relevant experimental models of ALI. Imatinib attenuates endotoxin (LPS)-induced vascular leak and lung inflammation in mice but exacerbates these features in a mouse model of ventilator-induced lung injury (VILI). We next explored these discrepant observations in vitro through investigation of the roles for Abl kinases in cultured lung EC. Imatinib attenuates LPS-induced lung EC permeability, restores VE-cadherin junctions, and reduces inflammation by suppressing VCAM-1 expression and inflammatory cytokine (IL-8 and IL-6) secretion. Conversely, in EC exposed to pathological 18% cyclic stretch (CS) (in vitro model of VILI), imatinib decreases VE-cadherin expression, disrupts cell-cell junctions, and increases IL-8 levels. Downregulation of c-Abl expression with siRNA attenuates LPS-induced VCAM-1 expression, whereas specific reduction of Arg reduces VE-cadherin expression in 18% CS-challenged ECs to mimic the imatinib effects. In summary, imatinib exhibits pulmonary barrier-protective and anti-inflammatory effects in LPS-injured mice and lung EC; however, imatinib exacerbates VILI as well as dysfunction in 18% CS-EC. These findings identify the Abl family kinases as important modulators of EC function and potential therapeutic targets in lung injury syndromes.
The cardiac protein αT-catenin contributes to chemical-induced asthma
Authors: Folmsbee Stephen Sai , Morales-Nebreda Luisa , Van Hengel Jolanda , Tyberghein Koen , Van Roy Frans , Budinger G. R. Scott , Bryce Paul J. , Gottardi Cara J.
Published: December 2014

Ten to 25% of adult asthma is occupational induced, a subtype caused by exposure to workplace chemicals. A recent genomewide association study identified single-nucleotide polymorphisms in the cardiac protein αT-catenin (αT-cat) that correlated with the incidence and severity of toluene diisocyanate (TDI) occupational asthma. αT-cat is a critical mediator of cell-cell adhesion and is predominantly expressed in cardiomyocytes, but its connection to asthma remains unknown. Therefore, we sought to determine the primary αT-cat-expressing cell type in the lung and its contribution to lung physiology in a murine model of TDI asthma. We show that αT-cat is expressed in lung within the cardiac sheath of pulmonary veins. Mechanically ventilated αT-cat knockout (KO) mice exhibit a significantly increased pressure-volume curve area compared with wild-type (WT) mice, suggesting that αT-cat loss affects lung hysteresis. Using a murine model of TDI asthma, we find that αT-cat KO mice show increased airway hyperresponsiveness to methacholine compared with WT mice. Bronchoalveolar lavage reveals only a mild macrophage-dominant inflammation that is not significantly different between WT and KO mice. These data suggest that αT-cat may contribute to asthma through a mechanism independent of inflammation and related to heart and pulmonary vein dysfunction.
PD-1/SHP-2 Inhibits Tc1/Th1 Phenotypic Responses and the Activation of T Cells in the Tumor Microenvironment
Authors: Li Jing , Jie Hyun-Bae , Lei Yu , Gildener-Leapman Neil , Trivedi Sumita , Green Tony , Kane Lawrence P. , Ferris Robert L.
Published: December 2014

Immune rejection of tumors is mediated by IFNγ production and T-cell cytolytic activity. These processes are impeded by PD-1, a coinhibitory molecule expressed on T cells that is elevated in tumor-infiltrating lymphocytes (TIL). PD-1 elevation may reflect T-cell exhaustion marked by decreased proliferation, production of type I cytokines, and poor cytolytic activity. Although anti–PD-1 antibodies enhance IFNγ secretion after stimulation of the T-cell receptor (TCR), the mechanistic link between PD-1 and its effects on T-cell help (Tc1/Th1 skewing) remains unclear. In prospectively collected cancer tissues, we found that TIL exhibited dampened Tc1/Th1 skewing and activation compared with peripheral blood lymphocytes (PBL). When PD-1 bound its ligand PD-L1, we observed a marked suppression of critical TCR target genes and Th1 cytokines. Conversely, PD-1 blockade reversed these suppressive effects of PD-1:PD-L1 ligation. We also found that the TCR-regulated phosphatase SHP-2 was expressed higher in TIL than in PBL, tightly correlating with PD-1 expression and negative regulation of TCR target genes. Overall, these results defined a PD-1/SHP-2/STAT1/T-bet signaling axis mediating the suppressive effects of PD-1 on Th1 immunity at tumor sites. Our findings argue that PD-1 or SHP-2 blockade will be sufficient to restore robust Th1 immunity and T-cell activation and thereby reverse immunosuppression in the tumor microenvironment. Cancer Res; 75(3); 508–18. ©2014 AACR.
Identification of a Functional SNP in the 3′UTR of CXCR2 That Is Associated with Reduced Risk of Lung Cancer
Authors: Ryan Bríd M. , Robles Ana I. , McClary Andrew C. , Haznadar Majda , Bowman Elise D. , Pine Sharon R. , Brown Derek , Khan Mohammed , Shiraishi Kouya , Kohno Takashi , Okayama Hirokazu , Modali Ramakrishna , Yokota Jun , Harris Curtis C.
Published: December 2014

Global changes in gene expression accompany the development of cancer. Thus, inherited variants in miRNA-binding sites are likely candidates for conferring inherited susceptibility. Using an in silico approach, we compiled a comprehensive list of SNPs predicted to modulate miRNA binding in genes from several key lung cancer pathways. We then investigated whether these SNPs were associated with lung cancer risk in two independent populations. In general, SNPs in miRNA-binding sites are rare. However, some allelic variation was observed. We found that rs1126579 in CXCR2 was associated with a reduced risk of lung cancer in both European American [ORTT vs. CC 0.56 (0.37–0.88); P = 0.008] and Japanese [ORTT vs. CC 0.62 (0.38–1.00); P = 0.049] populations. Furthermore, we found that the SNP disrupted a novel binding site for miR-516a-3p, led to a moderate increase in CXCR2 mRNA and protein expression, and increased MAPK signaling. Moreover, analysis of rs1126579 with serum levels of IL8, its endogenous ligand, supported an interaction whereby rs1126579-T and high serum IL8 conferred synergistic protection from lung cancer. Our findings demonstrate a function for a 3′UTR SNP in modulating CXCR2 expression, signaling, and susceptibility to lung cancer. Cancer Res; 75(3); 566–75. ©2014 AACR.