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Find video protocols related to scientific articles indexed in Pubmed.
Did Hospital Engagement Networks Actually Improve Care?
N. Engl. J. Med.
PUBLISHED: 11-20-2014
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To the Editor: The Partnership for Patients model test (PfP), discussed in a Perspective article by Pronovost and Jha (Aug. 21 issue),(1) is a large-scale quality-improvement program designed to make hospital care safer, more reliable, and less costly by engaging the nation's hospitals in work to reduce 30-day all-cause readmissions and preventable all-cause harm. We are writing to respond to several points made in the article. First, the test model, like all models from the Centers for Medicare and Medicaid Services (CMS) Innovation Center, does have an independent evaluation. The first evaluation report is posted publicly.(2),(3) Second, the evaluation . . .
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Intraluminal Thrombus, Intraplaque Hemorrhage, Plaque Thickness, and Current Smoking Optimally Predict Carotid Stroke.
Stroke
PUBLISHED: 11-20-2014
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Intraplaque hemorrhage (IPH) is associated with acute and future stroke. IPH is also associated with lumen markers of stroke risk including stenosis, plaque thickness, and ulceration. Whether IPH adds further predictive value to these other variables is unknown. The purpose of this study was to determine whether IPH improves carotid-source stroke prediction.
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The Synthesis of Fused Bicyclic Piperidines: Potential Bioactive Templates for Medicinal Chemistry.
J. Org. Chem.
PUBLISHED: 11-19-2014
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An array of six pyridyl-substituted fused bicyclic piperidines was prepared as novel cores for medicinal chemistry. For maximum diversity, the size of the fused ring varied from three to six atoms, and contained up to two oxygen atoms. The pyridine ring was incorporated to improve physicochemical properties and to challenge the robustness of the chemistry. The presence of the pyridine did interfere with our initial approaches to these molecules, and in several instances, a blocking strategy had to be employed. These new scaffolds possess high sp3 character and may prove useful in multiple medicinal chemistry applications.
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A METHOD FOR INDUCING AND DETERMINING BIOMECHANICS ASSOCIATED WITH ENDPLATE FRACTURES IN THE LUMBAR SPINE.
Biomed Sci Instrum
PUBLISHED: 11-19-2014
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Lumbar spine endplate fracture is not easily detectible using medical imaging, but can lead to pain symptoms. Understanding endplate fracture mechanics can lead to more informed clinical diagnosis and more appropriate safety enhancements for civilian and military vehicles. Lumbar motion segments obtained from PMHS were prepared using two methods. Group 1 (n=6) was potted preserving the natural segmental lordosis while Group 2 (n=4) removed the curvature. Specimens were compressed at 0.5 mm/sec until fracture, observed via real-time fluoroscopy video as radio-opaque dye transferred from the intervertebral disc nucleus into the vertebral body. Fracture was confirmed using CT and dissection. Force, bony acoustics and disc pressure were correlates of fracture. Fractures in Group 1 (5 of 6 specimens) were concentrated in the posterior cortex of the inferior vertebral body whereas Group 2 experienced endplate fractures. The mean sagittal plane angle between endplates for specimens with cortical fracture was 5.1±1.2 degrees, compared to 1.0±0.5 degrees for endplate fracture. The average peak force for cortical fracture was 10.0±1.9 kN and 4.5±0.8 kN for endplate fracture. Pre-positioning during compressive loading has a significant role in determining whether a motion segment sustains a cortical or endplate fracture. Likewise, an appropriately oriented segment can sustain endplate fracture at approximately 45% of the load for cortex fracture.
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DEVELOPMENT AND VERIFICATION OF A HYDROSTATIC PRESSURE CHAMBER FOR DETERMINING THE EFFFECT OF PRESSURE ON LIVER PROGENITOR CELLS.
Biomed Sci Instrum
PUBLISHED: 11-19-2014
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Hepatic progenitor cells (HPCs) have regenerative properties that could aid the development of treatments for severe liver disease. To study how pressure influences HPC fate, a hydrostatic pressure-controlled cell culture chamber was developed. The design incorporates custom LabView scripting for enhanced pressure regulation and data acquisition. Pressure can be controlled within ±0.2mmHg. Continuous airflow permits gas exchange, and CO2 is maintained at 5%±0.2%. Applied pressures range from 5 to 20 mmHg, reflecting interstitial pressure conditions in healthy and diseased livers, respectively. Bipotential Murine Oval Liver (BMOL) cells, an HPC-like cell line, were cultured in the chamber to test for maintenance of cell viability, adequate CO2 regulation, and maintenance of adequate media volume over 24 hours. Cultured cells were exposed to 5 or 19 mmHg. After 24 hours, media pH was measured, viable cells were counted (Trypan Blue, n=3), and plates were weighed to assess fluid loss. The number of live cells cultured under pressure vs. control conditions was not statistically different (p>.05). The pH remained constant at 7.0 for all conditions, suggesting adequate gas exchange. Evaporation of media was minimal at 3.97%. Results indicate that the pressure chamber provides appropriate environmental conditions for future studies on HPC pressure sensitivity.
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Polyunsaturated Fatty Acid Metabolites as Novel Lipidomic Biomarkers for Noninvasive Diagnosis of Nonalcoholic Steatohepatitis.
J. Lipid Res.
PUBLISHED: 11-19-2014
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Non-invasive diagnosis of nonalcoholic steatohepatitis (NASH) is a major unmet clinical need, and we hypothesized that polyunsaturated fatty acid (PUFA) metabolites, in particular the arachidonic acid (AA) derived eicosanoids, in the plasma would differentiate patients with nonalcoholic fatty liver (NAFL) from those with NASH. Therefore, we aimed to assess the differences in the plasma eicosanoid lipidomic profile between patients with biopsy-proven NAFL versus NASH versus non-NAFLD normal controls (based upon MRI fat fraction <5%). We carried out a cross-sectional analysis of a prospective nested case-control study including 10 patients with biopsy-proven NAFL, 9 patients with biopsy-proven NASH and 10 non-NAFLD MRI-phenotyped normal controls. We quantitatively compared the plasma eicosanoid and other PUFA metabolite levels between NAFL, versus NASH versus normal controls. Utilizing a uniquely well-characterized cohort, we demonstrated that plasma eicosanoid and other PUFA metabolite profiling can differentiate between NAFL and NASH. The top candidate as a single biomarker for differentiating NAFL from NASH was 11,12-dihydroxy-eicosatrienoic acid (11,12-diHETrE) with an AUROC of 1. In addition, we also found a panel including 13,14-dihydro-15-keto prostaglandin D2 (dkPGD2) and 20-carboxy arachidonic acid (20-COOH AA) that demonstrated an AUROC of 1. This proof of concept study provides early evidence that 11,12-diHETrE , dkPGD2 and 20-COOH AA are the leading eicosanoid candidate biomarkers for the non-invasive diagnosis of NASH.
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Is response to price equal for those with higher alcohol consumption?
Eur J Health Econ
PUBLISHED: 10-27-2014
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To determine if taxation policies that increase the price of alcohol differentially reduce alcohol consumption for heavy drinkers in Australia.
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Crash Characteristics and Injury Patterns of Restrained Front Seat Occupants in Far-side Impacts.
Traffic Inj Prev
PUBLISHED: 10-14-2014
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The study was conducted to determine the association between vehicle-, crash-, and demographic-related factors and injuries to front seat far-side occupants in modern environments.
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Three-dimensional enhanced lipidomics analysis combining UPLC, differential ion mobility spectrometry, and mass spectrometric separation strategies.
J. Lipid Res.
PUBLISHED: 09-15-2014
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Phospholipids serve as central structural components in cellular membranes and as potent mediators in numerous signaling pathways. There are six main classes of naturally occurring phospholipids distinguished by their distinct polar head groups that contain many unique molecular species with distinct fatty acid composition. Phospholipid molecular species are often expressed as isobaric species that are denoted by the phospholipid class and the total number of carbon atoms and double bonds contained in the esterified fatty acyl groups (e.g., phosphatidylcholine 34:2). Techniques to separate these molecules exist, and each has positive and negative attributes. Hydrophilic interaction liquid chromatography uses polar bonded silica to separate lipids by polar head group but not by specific molecular species. Reversed phase (RP) chromatography can separate by fatty acyl chain composition but not by polar head group. Herein we describe a new strategy called differential ion mobility spectrometry (DMS), which separates phospholipid classes by their polar head group. Combining DMS with current LC methods enhances phospholipid separation by increasing resolution, specificity, and signal-to-noise ratio. Additional application of specialized information-dependent acquisition methodologies along with RP chromatography allows full isobaric resolution, identification, and compositional characterization of specific phospholipids at the molecular level.
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A Phase III study of radiation therapy (RT) and O(6)-benzylguanine + BCNU versus RT and BCNU alone and methylation status in newly diagnosed glioblastoma and gliosarcoma: Southwest Oncology Group (SWOG) study S0001.
Int. J. Clin. Oncol.
PUBLISHED: 09-09-2014
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To determine the efficacy of methylguanine methyltransferase (MGMT) depletion + BCNU [1,3-bis(2-chloroethyl)-1- nitrosourea: carmustine] therapy and the impact of methylation status in adults with glioblastoma multiforme (GBM) and gliosarcoma.
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Sampling strategies for subsampled segmented EPI PRF thermometry in MR guided high intensity focused ultrasound.
Med Phys
PUBLISHED: 09-05-2014
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To investigate k-space subsampling strategies to achieve fast, large field-of-view (FOV) temperature monitoring using segmented echo planar imaging (EPI) proton resonance frequency shift thermometry for MR guided high intensity focused ultrasound (MRgHIFU) applications.
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Inhibition of group IVA cytosolic phospholipase A2 by thiazolyl ketones in vitro, ex vivo, and in vivo.
J. Med. Chem.
PUBLISHED: 09-03-2014
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Group IVA cytosolic phospholipase A2 (GIVA cPLA2) is the rate-limiting provider of pro-inflammatory mediators in many tissues and is thus an attractive target for the development of novel anti-inflammatory agents. In this work, we present the synthesis of new thiazolyl ketones and the study of their activities in vitro, in cells, and in vivo. Within this series of compounds, methyl 2-(2-(4-octylphenoxy)acetyl)thiazole-4-carboxylate (GK470) was found to be the most potent inhibitor of GIVA cPLA2, exhibiting an XI(50) value of 0.011 mole fraction in a mixed micelle assay and an IC50 of 300 nM in a vesicle assay. In a cellular assay using SW982 fibroblast-like synoviocytes, it suppressed the release of arachidonic acid with an IC50 value of 0.6 ?M. In a prophylactic collagen-induced arthritis model, it exhibited an anti-inflammatory effect comparable to the reference drug methotrexate, whereas in a therapeutic model, it showed results comparable to those of the reference drug Enbrel. In both models, it significantly reduced plasma PGE2 levels.
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Phospholipase A2 regulates eicosanoid class switching during inflammasome activation.
Proc. Natl. Acad. Sci. U.S.A.
PUBLISHED: 08-19-2014
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Initiation and resolution of inflammation are considered to be tightly connected processes. Lipoxins (LX) are proresolution lipid mediators that inhibit phlogistic neutrophil recruitment and promote wound-healing macrophage recruitment in humans via potent and specific signaling through the LXA4 receptor (ALX). One model of lipoxin biosynthesis involves sequential metabolism of arachidonic acid by two cell types expressing a combined transcellular metabolon. It is currently unclear how lipoxins are efficiently formed from precursors or if they are directly generated after receptor-mediated inflammatory commitment. Here, we provide evidence for a pathway by which lipoxins are generated in macrophages as a consequence of sequential activation of toll-like receptor 4 (TLR4), a receptor for endotoxin, and P2X7, a purinergic receptor for extracellular ATP. Initial activation of TLR4 results in accumulation of the cyclooxygenase-2-derived lipoxin precursor 15-hydroxyeicosatetraenoic acid (15-HETE) in esterified form within membrane phospholipids, which can be enhanced by aspirin (ASA) treatment. Subsequent activation of P2X7 results in efficient hydrolysis of 15-HETE from membrane phospholipids by group IVA cytosolic phospholipase A2, and its conversion to bioactive lipoxins by 5-lipoxygenase. Our results demonstrate how a single immune cell can store a proresolving lipid precursor and then release it for bioactive maturation and secretion, conceptually similar to the production and inflammasome-dependent maturation of the proinflammatory IL-1 family cytokines. These findings provide evidence for receptor-specific and combinatorial control of pro- and anti-inflammatory eicosanoid biosynthesis, and potential avenues to modulate inflammatory indices without inhibiting downstream eicosanoid pathways.
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Differential expression and regulation of vitamin D hydroxylases and inflammatory genes in prostate stroma and epithelium by 1,25-dihydroxyvitamin D in men with prostate cancer and an in vitro model.
J. Steroid Biochem. Mol. Biol.
PUBLISHED: 08-15-2014
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Previous work on vitamin D in the prostate has focused on the prostatic epithelium, from which prostate cancer arises. Prostatic epithelial cells are surrounded by stroma, which has well-established regulatory control over epithelial proliferation, differentiation, and the inflammatory response. Here we examined the regulation of vitamin D-related genes and inflammatory genes by 1?,25-dihydroxyvitamin D3 (1,25(OH)2D) in laser-capture microdissected prostate tissue from a vitamin D3 clinical trial and in an in vitro model that facilitates stromal-epithelial crosstalk. Analysis of the trial tissues showed that VDR was present in both cell types, whereas expression of the hydroxylases was the highest in the epithelium. Examination of gene expression by prostatic (1,25(OH)2D) concentrations showed that VDR was significantly lower in prostate tissues with the highest concentration of 1,25(OH)2D, and down-regulation of VDR by 1,25(OH) 2D was confirmed in the primary cell cultures. Analysis of inflammatory genes in the patient tissues revealed that IL-6 expression was the highest in the prostate stroma while PTGS2 (COX2) levels were lowest in the prostate cancer tissues from men in the highest tertile of prostatic 1,25(OH)2D. In vitro, TNF-?, IL-6 and IL-8 were suppressed by 1,25 (OH)2D in the primary epithelial cells, whereas TNF-? and PTGS2 were suppressed by 1,25(OH) 2D in the stromal cells. Importantly, the ability of 1,25(OH)2D to alter pro-inflammatory-induced changes in epithelial cell growth were dependent on the presence of the stromal cells. In summary, whereas both stromal and epithelial cells of the prostate express VDR and can presumably respond to 1,25(OH)2D, which appears to be primarily produced by the prostatic epithelium. Further, while the prostate epithelium was more responsive to the anti-inflammatory activity of 1,25 (OH)2D than stromal cells, stroma-epithelial crosstalk enhanced the phenotypic effects of 1,25(OH)2D and the inflammatory process in the prostate gland.
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An overview of measurement activities in the partnership for patients.
J Patient Saf
PUBLISHED: 08-15-2014
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The Partnership for Patients, launched in April 2011, is a national quality improvement initiative from the Department of Health and Human Services that has set ambitious goals for U.S. providers to improve patient safety and care transitions. This paper outlines the initiative's measurement strategy, describing four measurement-related objectives: (1) to track national progress toward the program goals that U.S. hospitals reduce preventable adverse events by 40% and readmissions by 20%; (2) to support local quality improvement measurement in participating hospitals by providing the appropriate tools, training, and programmatic structure; (3) to obtain feedback on hospital and contractor progress, in close to real time, so the project can be effectively managed; and (4) to evaluate the program's impact on adverse event and readmission rates.
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Severe hypoglycemia and mortality after cardiovascular events for type 1 diabetic patients in sweden.
Diabetes Care
PUBLISHED: 08-04-2014
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To examine whether previous severe hypoglycemic events were associated with the risk of all-cause mortality after major cardiovascular events (myocardial infarction [MI] or stroke) in patients with type 1 diabetes.
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Mechanical yield of the lumbar annulus: a possible contributor to instability: Laboratory investigation.
J Neurosurg Spine
PUBLISHED: 08-01-2014
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Segmental instability in the lumbar spine can result from a number of mechanisms including intervertebral disc degeneration and facet joint degradation. Under traumatic circumstances, elevated loading may lead to mechanical yield of the annular fibers, which can decrease load-carrying capacity and contribute to instability. The purpose of this study was to quantify the biomechanics of intervertebral annular yield during tensile loading with respect to spinal level and anatomical region within the intervertebral disc.
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Targeted Deletion and Lipidomic Analysis Identify Epithelial Cell COX-2 as a Major Driver of Chemically Induced Skin Cancer.
Mol. Cancer Res.
PUBLISHED: 07-25-2014
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Pharmacologic and global gene deletion studies demonstrate that cyclooxygenase-2 (PTGS2/COX-2) plays a critical role in DMBA/TPA-induced skin tumor induction. Although many cell types in the tumor microenvironment express COX-2, the cell types in which COX-2 expression is required for tumor promotion are not clearly established. Here, cell type-specific Cox-2 gene deletion reveals a vital role for skin epithelial cell COX-2 expression in DMBA/TPA tumor induction. In contrast, myeloid Cox-2 gene deletion has no effect on DMBA/TPA tumorigenesis. The infrequent, small tumors that develop on mice with an epithelial cell-specific Cox-2 gene deletion have decreased proliferation and increased cell differentiation properties. Blood vessel density is reduced in tumors with an epithelial cell-specific Cox-2 gene deletion, compared with littermate control tumors, suggesting a reciprocal relationship in tumor progression between COX-2-expressing tumor epithelial cells and microenvironment endothelial cells. Lipidomics analysis of skin and tumors from DMBA/TPA-treated mice suggests that the prostaglandins PGE2 and PGF2? are likely candidates for the epithelial cell COX-2-dependent eicosanoids that mediate tumor progression. This study both illustrates the value of cell type-specific gene deletions in understanding the cellular roles of signal-generating pathways in complex microenvironments and emphasizes the benefit of a systems-based lipidomic analysis approach to identify candidate lipid mediators of biologic responses.
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Cancer therapy. Ex vivo culture of circulating breast tumor cells for individualized testing of drug susceptibility.
Science
PUBLISHED: 07-12-2014
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Circulating tumor cells (CTCs) are present at low concentrations in the peripheral blood of patients with solid tumors. It has been proposed that the isolation, ex vivo culture, and characterization of CTCs may provide an opportunity to noninvasively monitor the changing patterns of drug susceptibility in individual patients as their tumors acquire new mutations. In a proof-of-concept study, we established CTC cultures from six patients with estrogen receptor-positive breast cancer. Three of five CTC lines tested were tumorigenic in mice. Genome sequencing of the CTC lines revealed preexisting mutations in the PIK3CA gene and newly acquired mutations in the estrogen receptor gene (ESR1), PIK3CA gene, and fibroblast growth factor receptor gene (FGFR2), among others. Drug sensitivity testing of CTC lines with multiple mutations revealed potential new therapeutic targets. With optimization of CTC culture conditions, this strategy may help identify the best therapies for individual cancer patients over the course of their disease.
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Capecitabine and oxaliplatin in the preoperative multimodality treatment of rectal cancer: surgical end points from National Surgical Adjuvant Breast and Bowel Project trial R-04.
J. Clin. Oncol.
PUBLISHED: 05-05-2014
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The optimal chemotherapy regimen administered concurrently with preoperative radiation therapy (RT) for patients with rectal cancer is unknown. National Surgical Adjuvant Breast and Bowel Project trial R-04 compared four chemotherapy regimens administered concomitantly with RT.
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Comprehensive ultra-performance liquid chromatographic separation and mass spectrometric analysis of eicosanoid metabolites in human samples.
J Chromatogr A
PUBLISHED: 05-01-2014
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Over the past decade, the number of known eicosanoids has expanded immensely and we have now developed an ultra-performance liquid chromatography-electrospray ionization triple quadrupole mass spectrometric (UPLC-QTRAP/MS/MS) method to monitor and quantify numerous eicosanoids. The UPLC-QTRAP/MS/MS approach utilizes scheduled multiple reaction monitoring (MRM) to optimize sensitivity, number of metabolites that can be analyzed and the time requirement of the analysis. A total of 184 eicosanoids including 26 deuterated internal standards can be separated and monitored in a single 5min UPLC run. To demonstrate a practical application, human plasma samples were analyzed following solid-phase extraction (SPE) and the recovery rate and matrix effects were determined for the 26 deuterated internal standards added to the plasma. The method was validated and shown to be sensitive with the limit of quantitation at pg levels for most compounds, accurate with recovery rates of 70-120%, and precise with a CV<30 for all compounds. Also, the method showed a linear response over a range spanning several orders of magnitude. In a QC human plasma sample, we identified and rigorously quantified over 120 eicosanoids.
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Convergent loss of PTEN leads to clinical resistance to a PI(3)K? inhibitor.
Nature
PUBLISHED: 04-29-2014
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Broad and deep tumour genome sequencing has shed new light on tumour heterogeneity and provided important insights into the evolution of metastases arising from different clones. There is an additional layer of complexity, in that tumour evolution may be influenced by selective pressure provided by therapy, in a similar fashion to that occurring in infectious diseases. Here we studied tumour genomic evolution in a patient (index patient) with metastatic breast cancer bearing an activating PIK3CA (phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit alpha, PI(3)K?) mutation. The patient was treated with the PI(3)K? inhibitor BYL719, which achieved a lasting clinical response, but the patient eventually became resistant to this drug (emergence of lung metastases) and died shortly thereafter. A rapid autopsy was performed and material from a total of 14 metastatic sites was collected and sequenced. All metastatic lesions, when compared to the pre-treatment tumour, had a copy loss of PTEN (phosphatase and tensin homolog) and those lesions that became refractory to BYL719 had additional and different PTEN genetic alterations, resulting in the loss of PTEN expression. To put these results in context, we examined six other patients also treated with BYL719. Acquired bi-allelic loss of PTEN was found in one of these patients, whereas in two others PIK3CA mutations present in the primary tumour were no longer detected at the time of progression. To characterize our findings functionally, we examined the effects of PTEN knockdown in several preclinical models (both in cell lines intrinsically sensitive to BYL719 and in PTEN-null xenografts derived from our index patient), which we found resulted in resistance to BYL719, whereas simultaneous PI(3)K p110? blockade reverted this resistance phenotype. We conclude that parallel genetic evolution of separate metastatic sites with different PTEN genomic alterations leads to a convergent PTEN-null phenotype resistant to PI(3)K? inhibition.
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Carotid MRI Detection of Intraplaque Hemorrhage at 3T and 1.5T.
J Neuroimaging
PUBLISHED: 03-27-2014
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Carotid intraplaque hemorrhage leads to plaque progression and ischemic events. Detection can be accomplished with 3T T1w sequences, but may be limited by false-positive lipid/necrosis. The purpose of this study was threefold: (1) to determine if magnetization-prepared rapid acquisition with gradient-echo (MPRAGE) detects intraplaque hemorrhage versus lipid/necrosis; (2) if 3T MPRAGE image quality is retained at 1.5T; and (3) to determine observer agreement.
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Relative health performance in BRICS over the past 20 years: the winners and losers.
Bull. World Health Organ.
PUBLISHED: 03-23-2014
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To determine whether the health performance of Brazil, the Russian Federation, India, China and South Africa--the countries known as BRICS--has kept in step with their economic development.
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Intervertebral disc height loss demonstrates the threshold of major pathological changes during degeneration.
Eur Spine J
PUBLISHED: 03-04-2014
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Quantitative MRI techniques were utilized to study intervertebral disc degeneration. Main focus was to develop a novel approach to quantify disc height loss associated with disc degeneration. Currently there is no universally accepted metric of degeneration based on measurement of disc height. Such quantitative imaging methods would complement qualitative visual assessment methods currently used and offer a valuable diagnostic tool.
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The effectiveness of community action in reducing risky alcohol consumption and harm: a cluster randomised controlled trial.
PLoS Med.
PUBLISHED: 03-01-2014
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The World Health Organization, governments, and communities agree that community action is likely to reduce risky alcohol consumption and harm. Despite this agreement, there is little rigorous evidence that community action is effective: of the six randomised trials of community action published to date, all were US-based and focused on young people (rather than the whole community), and their outcomes were limited to self-report or alcohol purchase attempts. The objective of this study was to conduct the first non-US randomised controlled trial (RCT) of community action to quantify the effectiveness of this approach in reducing risky alcohol consumption and harms measured using both self-report and routinely collected data.
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Release and capture of bioactive oxidized phospholipids and oxidized cholesteryl esters during percutaneous coronary and peripheral arterial interventions in humans.
J. Am. Coll. Cardiol.
PUBLISHED: 01-27-2014
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This study sought to assess whether oxidized lipids are released downstream from obstructive plaques after percutaneous coronary and peripheral interventions using distal protection devices.
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Cell-type-specific roles for COX-2 in UVB-induced skin cancer.
Carcinogenesis
PUBLISHED: 01-27-2014
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In human tumors, and in mouse models, cyclooxygenase-2 (COX-2) levels are frequently correlated with tumor development/burden. In addition to intrinsic tumor cell expression, COX-2 is often present in fibroblasts, myofibroblasts and endothelial cells of the tumor microenvironment, and in infiltrating immune cells. Intrinsic cancer cell COX-2 expression is postulated as only one of many sources for prostanoids required for tumor promotion/progression. Although both COX-2 inhibition and global Cox-2 gene deletion ameliorate ultraviolet B (UVB)-induced SKH-1 mouse skin tumorigenesis, neither manipulation can elucidate the cell type(s) in which COX-2 expression is required for tumorigenesis; both eliminate COX-2 activity in all cells. To address this question, we created Cox-2(flox/flox) mice, in which the Cox-2 gene can be eliminated in a cell-type-specific fashion by targeted Cre recombinase expression. Cox-2 deletion in skin epithelial cells of SKH-1 Cox-2(flox/flox);K14Cre(+) mice resulted, following UVB irradiation, in reduced skin hyperplasia and increased apoptosis. Targeted epithelial cell Cox-2 deletion also resulted in reduced tumor incidence, frequency, size and proliferation rate, altered tumor cell differentiation and reduced tumor vascularization. Moreover, Cox-2(flox/flox);K14Cre(+) papillomas did not progress to squamous cell carcinomas. In contrast, Cox-2 deletion in SKH-1 Cox-2(flox/flox); LysMCre(+) myeloid cells had no effect on UVB tumor induction. We conclude that (i) intrinsic epithelial COX-2 activity plays a major role in UVB-induced skin cancer, (ii) macrophage/myeloid COX-2 plays no role in UVB-induced skin cancer and (iii) either there may be another COX-2-dependent prostanoid source(s) that drives UVB skin tumor induction or there may exist a COX-2-independent pathway(s) to UVB-induced skin cancer.
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Modeling of eicosanoid fluxes reveals functional coupling between cyclooxygenases and terminal synthases.
Biophys. J.
PUBLISHED: 01-10-2014
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Eicosanoids, including prostaglandins (PG) and leukotrienes, are lipid mediators derived from arachidonic acid. A quantitative and biochemical level understanding of eicosanoid metabolism would aid in understanding the mechanisms that govern inflammatory processes. Here, we present a combined experimental and computational approach to understanding the biochemical basis of eicosanoid metabolism in macrophages. Lipidomic and transcriptomic measurements and analyses reveal temporal and dynamic changes of the eicosanoid metabolic network in mouse bone marrow-derived macrophages (BMDM) upon stimulation of the Toll-like receptor 4 with Kdo2-Lipid A (KLA) and stimulation of the P2X7 purinergic receptor with adenosine 5'-triphosphate. Kinetic models were developed for the cyclooxygenase (COX) and lipoxygenase branches of arachidonic acid metabolism, and then the rate constants were estimated with a data set from ATP-stimulated BMDM, using a two-step matrix-based approach employing a constrained least-squares method followed by nonlinear optimization. The robustness of the model was validated through parametric sensitivity, uncertainty analysis, and predicting an independent dataset from KLA-primed ATP-stimulated BMDM by allowing the parameters to vary within the uncertainty range of the calculated parameters. We analyzed the functional coupling between COX isozymes and terminal enzymes by developing a PGH2-divided model. This provided evidence for the functional coupling between COX-2 and PGE2 synthase, between COX-1/COX-2 and PGD2 synthase, and also between COX-1 and thromboxane A2 synthase. Further, these functional couplings were experimentally validated using COX-1 and COX-2 selective inhibitors. The resulting fluxomics analysis demonstrates that the "multi-omics" systems biology approach can define the complex machinery of eicosanoid networks.
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Discrimination of Influenza Infection (A/2009 H1N1) from Prior Exposure by Antibody Protein Microarray Analysis.
PLoS ONE
PUBLISHED: 01-01-2014
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Reliable discrimination of recent influenza A infection from previous exposure using hemagglutination inhibition (HI) or virus neutralization tests is currently not feasible. This is due to low sensitivity of the tests and the interference of antibody responses generated by previous infections. Here we investigate the diagnostic characteristics of a newly developed antibody (HA1) protein microarray using data from cross-sectional serological studies carried out before and after the pandemic of 2009. The data are analysed by mixture models, providing a probabilistic classification of sera (susceptible, prior-exposed, recently infected). Estimated sensitivity and specificity for identifying A/2009 infections are low using HI (66% and 51%), and high when using A/2009 microarray data alone or together with A/1918 microarray data (96% and 95%). As a heuristic, a high A/2009 to A/1918 antibody ratio (>1.05) is indicative of recent infection, while a low ratio is indicative of a pre-existing response, even if the A/2009 titer is high. We conclude that highly sensitive and specific classification of individual sera is possible using the protein microarray, thereby enabling precise estimation of age-specific infection attack rates in the population even if sample sizes are small.
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Treatment envelope evaluation in transcranial magnetic resonance-guided focused ultrasound utilizing 3D MR thermometry.
J Ther Ultrasound
PUBLISHED: 01-01-2014
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Current clinical targets for transcranial magnetic resonance-guided focused ultrasound (tcMRgFUS) are all located close to the geometric center of the skull convexity, which minimizes challenges related to focusing the ultrasound through the skull bone. Non-central targets will have to be reached to treat a wider variety of neurological disorders and solid tumors. Treatment envelope studies utilizing two-dimensional (2D) magnetic resonance (MR) thermometry have previously been performed to determine the regions in which therapeutic levels of FUS can currently be delivered. Since 2D MR thermometry was used, very limited information about unintended heating in near-field tissue/bone interfaces could be deduced.
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25-hydroxycholesterol activates the integrated stress response to reprogram transcription and translation in macrophages.
J. Biol. Chem.
PUBLISHED: 11-04-2013
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25-Hydroxycholesterol (25OHC) is an enzymatically derived oxidation product of cholesterol that modulates lipid metabolism and immunity. 25OHC is synthesized in response to interferons and exerts broad antiviral activity by as yet poorly characterized mechanisms. To gain further insights into the basis for antiviral activity, we evaluated time-dependent responses of the macrophage lipidome and transcriptome to 25OHC treatment. In addition to altering specific aspects of cholesterol and sphingolipid metabolism, we found that 25OHC activates integrated stress response (ISR) genes and reprograms protein translation. Effects of 25OHC on ISR gene expression were independent of liver X receptors and sterol-response element-binding proteins and instead primarily resulted from activation of the GCN2/eIF2?/ATF4 branch of the ISR pathway. These studies reveal that 25OHC activates the integrated stress response, which may contribute to its antiviral activity.
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Lipidomics technologies at the end of the first decade and the beginning of the next.
Adv Nutr
PUBLISHED: 09-17-2013
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The lipidome is composed of all of the biomolecules defined as lipids, which encompass compounds of amazing structural diversity and complexity. It has been ?1 decade since the study of "lipidomics" was begun in earnest, and the technologies and tools for data analysis have advanced considerably over this period. This workshop summarized the scope of the lipidome and technologies for its analysis, lipidomics databases and other online tools, and examples of the application of lipidomics to nutritional research. The slides from the workshop, online lipidomics tools, and databases are available at http://www.lipidmaps.org.
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A lipidomic perspective on inflammatory macrophage eicosanoid signaling.
Adv Biol Regul
PUBLISHED: 09-15-2013
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Macrophages are central to essential physiological processes including the regulation of innate and adaptive immunity, but they are also central to a number of inflammatory disease states. These immune cells also possess remarkable plasticity and display various shades of functionalities based on changes in the surrounding molecular environment. Macrophage biology has defined various phenotypes and roles in inflammation based primarily on cytokine and chemokine profiles of cells in different activation states. Importantly, macrophages are elite producers of eicosanoids and other related lipid mediators during inflammation, but specific roles of these molecules have not generally been incorporated into the larger context of macrophage biology. In this review, we discuss the current classification of macrophage types and their roles in inflammation and disease, along with the practical challenges of studying biologically relevant phenotypes ex vivo. Using the latest advances in eicosanoid lipidomics, we highlight several key studies from our laboratory that provide a comprehensive understanding of how eicosanoid metabolism differs between macrophage phenotypes, along with how this metabolism is altered by changes in membrane fatty acid distribution and varied durations of Toll-like receptor (TLR) priming. In conclusion, we summarize several examples of the benefit of macrophage plasticity to develop accurate cellular mechanisms of lipid metabolism, and insights from lipidomic analyses about the differences in eicosanoid pathway enzyme activity in vitro vs. in cells ex vivo. Examples of new techniques to further understand the role of macrophage eicosanoid signaling in vivo are also discussed.
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UNDERSTANDING THE VERTICAL EQUITY JUDGEMENTS UNDERPINNING HEALTH INEQUALITY MEASURES.
Health Econ
PUBLISHED: 07-04-2013
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The choice of income-related health inequality measures in comparative studies is often determined by custom and analytical concerns, without much explicit consideration of the vertical equity judgements underlying alternative measures. This note employs an inequality map to illustrate how these judgements determine the ranking of populations by health inequality. In particular, it is shown that relative indices of inequality in health attainments and shortfalls embody distinct vertical equity judgments, where each may represent ethically defensible positions in specific contexts. Further research is needed to explore peoples preferences over distributions of income and health. Copyright © 2013 John Wiley & Sons, Ltd.
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Insertion of the Ca²?-independent phospholipase A? into a phospholipid bilayer via coarse-grained and atomistic molecular dynamics simulations.
PLoS Comput. Biol.
PUBLISHED: 07-01-2013
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Group VI Ca²?-independent phospholipase A? (iPLA?) is a water-soluble enzyme that is active when associated with phospholipid membranes. Despite its clear pharmaceutical relevance, no X-ray or NMR structural information is currently available for the iPLA? or its membrane complex. In this paper, we combine homology modeling with coarse-grained (CG) and all-atom (AA) molecular dynamics (MD) simulations to build structural models of iPLA? in association with a phospholipid bilayer. CG-MD simulations of the membrane insertion process were employed to provide a starting point for an atomistic description. Six AA-MD simulations were then conducted for 60 ns, starting from different initial CG structures, to refine the membrane complex. The resulting structures are shown to be consistent with each other and with deuterium exchange mass spectrometry (DXMS) experiments, suggesting that our approach is suitable for the modeling of iPLA? at the membrane surface. The models show that an anchoring region (residues 710-724) forms an amphipathic helix that is stabilized by the membrane. In future studies, the proposed iPLA? models should provide a structural basis for understanding the mechanisms of lipid extraction and drug-inhibition. In addition, the dual-resolution approach discussed here should provide the means for the future exploration of the impact of lipid diversity and sequence mutations on the activity of iPLA? and related enzymes.
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Toward real-time temperature monitoring in fat and aqueous tissue during magnetic resonance-guided high-intensity focused ultrasound using a three-dimensional proton resonance frequency T1 method.
Magn Reson Med
PUBLISHED: 07-01-2013
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To present a three-dimensional (3D) segmented echoplanar imaging (EPI) pulse sequence implementation that provides simultaneously the proton resonance frequency shift temperature of aqueous tissue and the longitudinal relaxation time (T1 ) of fat during thermal ablation.
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Longitudinal methods to investigate the role of health determinants in the dynamics of income-related health inequality.
J Health Econ
PUBLISHED: 06-30-2013
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The usual starting point for understanding changes in income-related health inequality (IRHI) over time has been regression-based decomposition procedures for the health concentration index. However the reliance on repeated cross-sectional analysis for this purpose prevents both the appropriate specification of the health function as a dynamic model and the identification of important determinants of the transition processes underlying IRHI changes such as those relating to mortality. This paper overcomes these limitations by developing alternative longitudinal procedures to analyse the role of health determinants in driving changes in IRHI through both morbidity changes and mortality, with our dynamic modelling framework also serving to identify their contribution to long-run or structural IRHI. The approach is illustrated by an empirical analysis of the causes of the increase in IRHI in Great Britain between 1999 and 2004.
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NCoR repression of LXRs restricts macrophage biosynthesis of insulin-sensitizing omega 3 fatty acids.
Cell
PUBLISHED: 06-18-2013
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Macrophage-mediated inflammation is a major contributor to obesity-associated insulin resistance. The corepressor NCoR interacts with inflammatory pathway genes in macrophages, suggesting that its removal would result in increased activity of inflammatory responses. Surprisingly, we find that macrophage-specific deletion of NCoR instead results in an anti-inflammatory phenotype along with robust systemic insulin sensitization in obese mice. We present evidence that derepression of LXRs contributes to this paradoxical anti-inflammatory phenotype by causing increased expression of genes that direct biosynthesis of palmitoleic acid and ?3 fatty acids. Remarkably, the increased ?3 fatty acid levels primarily inhibit NF-?B-dependent inflammatory responses by uncoupling NF-?B binding and enhancer/promoter histone acetylation from subsequent steps required for proinflammatory gene activation. This provides a mechanism for the in vivo anti-inflammatory insulin-sensitive phenotype observed in mice with macrophage-specific deletion of NCoR. Therapeutic methods to harness this mechanism could lead to a new approach to insulin-sensitizing therapies.
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Analysis of inflammatory and lipid metabolic networks across RAW264.7 and thioglycolate-elicited macrophages.
J. Lipid Res.
PUBLISHED: 06-17-2013
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Studies of macrophage biology have been significantly advanced by the availability of cell lines such as RAW264.7 cells. However, it is unclear how these cell lines differ from primary macrophages such as thioglycolate-elicited peritoneal macrophages (TGEMs). We used the inflammatory stimulus Kdo2-lipid A (KLA) to stimulate RAW264.7 and TGEM cells. Temporal changes of lipid and gene expression levels were concomitantly measured and a systems-level analysis was performed on the fold-change data. Here we present a comprehensive comparison between the two cell types. Upon KLA treatment, both RAW264.7 and TGEM cells show a strong inflammatory response. TGEM (primary) cells show a more rapid and intense inflammatory response relative to RAW264.7 cells. DNA levels (fold-change relative to control) are reduced in RAW264.7 cells, correlating with greater downregulation of cell cycle genes. The transcriptional response suggests that the cholesterol de novo synthesis increases considerably in RAW264.7 cells, but 25-hydroxycholesterol increases considerably in TGEM cells. Overall, while RAW264.7 cells behave similarly to TGEM cells in some ways and can be used as a good model for inflammation- and immune function-related kinetic studies, they behave differently than TGEM cells in other aspects of lipid metabolism and phenotypes used as models for various disorders such as atherosclerosis.
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Phase reconstruction from multiple coil data using a virtual reference coil.
Magn Reson Med
PUBLISHED: 06-12-2013
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This study develops a method to obtain optimal estimates of absolute magnetization phase from multiple-coil MRI data.
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Breast cancer index identifies early-stage estrogen receptor-positive breast cancer patients at risk for early- and late-distant recurrence.
Clin. Cancer Res.
PUBLISHED: 06-11-2013
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Residual risk of relapse remains a substantial concern for patients with hormone receptor-positive breast cancer, with approximately half of all disease recurrences occurring after five years of adjuvant antiestrogen therapy.
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Three-dimensional dynamic contrast enhanced imaging of the carotid artery with direct arterial input function measurement.
Magn Reson Med
PUBLISHED: 06-04-2013
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Kinetic analysis using dynamic contrast enhanced MRI to assess neovascularization of carotid plaque requires images with high spatial and temporal resolution. This work demonstrates a new three-dimensional (3D) dynamic contrast enhanced imaging sequence, which directly measures the arterial input function with high temporal resolution yet maintains the high spatial resolution required to identify areas of increased adventitial neovascularity.
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In vivo evaluation of multi-echo hybrid PRF/T1 approach for temperature monitoring during breast MR-guided focused ultrasound surgery treatments.
Magn Reson Med
PUBLISHED: 05-24-2013
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To evaluate the precision of in vivo temperature measurements in adipose and glandular breast tissue using a multi-echo hybrid PRF/T1 pulse sequence.
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New potent and selective polyfluoroalkyl ketone inhibitors of GVIA calcium-independent phospholipase A2.
Bioorg. Med. Chem.
PUBLISHED: 05-17-2013
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Group VIA calcium-independent phospholipase A2 (GVIA iPLA2) has recently emerged as an important pharmaceutical target. Selective and potent GVIA iPLA2 inhibitors can be used to study its role in various neurological disorders. In the current work, we explore the significance of the introduction of a substituent in previously reported potent GVIA iPLA2 inhibitors. 1,1,1,2,2-Pentafluoro-7-(4-methoxyphenyl)heptan-3-one (GK187) is the most potent and selective GVIA iPLA2 inhibitor ever reported with a XI(50) value of 0.0001, and with no significant inhibition against GIVA cPLA2 or GV sPLA2. We also compare the inhibition of two difluoromethyl ketones on GVIA iPLA2, GIVA cPLA2, and GV sPLA2.
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Cervical spine injury biomechanics: Applications for under body blast loadings in military environments.
Clin Biomech (Bristol, Avon)
PUBLISHED: 05-03-2013
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While cervical spine injury biomechanics reviews in motor vehicle and sports environments are available, there is a paucity of studies in military loadings. This article presents an analysis on the biomechanics and applications of cervical spine injury research with an emphasis on human tolerance for underbody blast loadings in the military.
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Planning cancer control in Latin America and the Caribbean.
Lancet Oncol.
PUBLISHED: 05-01-2013
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Non-communicable diseases, including cancer, are overtaking infectious disease as the leading health-care threat in middle-income and low-income countries. Latin American and Caribbean countries are struggling to respond to increasing morbidity and death from advanced disease. Health ministries and health-care systems in these countries face many challenges caring for patients with advanced cancer: inadequate funding; inequitable distribution of resources and services; inadequate numbers, training, and distribution of health-care personnel and equipment; lack of adequate care for many populations based on socioeconomic, geographic, ethnic, and other factors; and current systems geared toward the needs of wealthy, urban minorities at a cost to the entire population. This burgeoning cancer problem threatens to cause widespread suffering and economic peril to the countries of Latin America. Prompt and deliberate actions must be taken to avoid this scenario. Increasing efforts towards prevention of cancer and avoidance of advanced, stage IV disease will reduce suffering and mortality and will make overall cancer care more affordable. We hope the findings of our Commission and our recommendations will inspire Latin American stakeholders to redouble their efforts to address this increasing cancer burden and to prevent it from worsening and threatening their societies.
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Tumor suppressor microRNAs, miR-100 and -125b, are regulated by 1,25-dihydroxyvitamin D in primary prostate cells and in patient tissue.
Cancer Prev Res (Phila)
PUBLISHED: 03-15-2013
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MiR-100 and miR-125b are lost in many cancers and have potential function as tumor suppressors. Using both primary prostatic epithelial cultures and laser capture-microdissected prostate epithelium from 45 patients enrolled in a vitamin D3 randomized trial, we identified miR-100 and -125b as targets of 1,25-dihydroxyvitamin D3 (1,25D). In patients, miR-100 and -125b levels were significantly lower in tumor tissue than in benign prostate. Similarly, miR-100 and -125b were lower in primary prostate cancer cells than in cells derived from benign prostate. Prostatic concentrations of 1,25D positively correlated with these miRNA levels in both prostate cancer and benign epithelium, showing that patients with prostate cancer may still benefit from vitamin D3. In cell assays, upregulation of these miRNAs by 1,25D was vitamin D receptor dependent. Transfection of pre-miR-100 and pre-miR-125b in the presence or absence of 1,25D decreased invasiveness of cancer cell, RWPE-2. Pre-miR-100 and pre-miR-125b decreased proliferation in primary cells and cancer cells respectively. Pre-miR-125b transfection suppressed migration and clonal growth of prostate cancer cells, whereas knockdown of miR-125b in normal cells increased migration indicates a tumor suppressor function. 1,25D suppressed expression of previously bona fide mRNA targets of these miRNAs, E2F3 and Plk1, in a miRNA-dependent manner. Together, these findings show that vitamin D3 supplementation augments tumor suppressive miRNAs in patient prostate tissue, providing evidence that miRNAs could be key physiologic mediators of vitamin D3 activity in prevention and early treatment of prostate cancer.
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Lipidomic profiling of influenza infection identifies mediators that induce and resolve inflammation.
Cell
PUBLISHED: 03-07-2013
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Bioactive lipid mediators play a crucial role in the induction and resolution of inflammation. To elucidate their involvement during influenza infection, liquid chromatography/mass spectrometry lipidomic profiling of 141 lipid species was performed on a mouse influenza model using two viruses of significantly different pathogenicity. Infection by the low-pathogenicity strain X31/H3N2 induced a proinflammatory response followed by a distinct anti-inflammatory response; infection by the high-pathogenicity strain PR8/H1N1 resulted in overlapping pro- and anti-inflammatory states. Integration of the large-scale lipid measurements with targeted gene expression data demonstrated that 5-lipoxygenase metabolites correlated with the pathogenic phase of the infection, whereas 12/15-lipoxygenase metabolites were associated with the resolution phase. Hydroxylated linoleic acid, specifically the ratio of 13- to 9-hydroxyoctadecadienoic acid, was identified as a potential biomarker for immune status during an active infection. Importantly, some of the findings from the animal model were recapitulated in studies of human nasopharyngeal lavages obtained during the 2009-2011 influenza seasons.
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Highly accelerated cardiac cine phase-contrast mri using an undersampled radial acquisition and temporally constrained reconstruction.
J Magn Reson Imaging
PUBLISHED: 03-06-2013
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PURPOSE: To evaluate a method to enable single-slice or multiple-slice cine phase contrast (cine-PC) acquisition during a single breath-hold using a highly sparsified radial acquisition ordering and temporally constrained image reconstruction with a spatially varying temporal constraint. MATERIALS AND METHODS: Simulated and in vivo cine-PC datasets of the proximal ascending aorta were obtained at different acceleration factors using a view projection acquisition order optimized for temporally constrained reconstruction (TCR). Reconstruction of the sparse cine-PC data performed with TCR was compared to reconstructions using zero-filled regridding and temporal interpolation. RESULTS: TCR resulted in more accurate velocity measurements than regridding or temporal interpolation. In one dataset, TCR of undersampled in vivo data (16 views per cardiac phase) resulted in a peak systolic velocity within 3.3% of the value measured by Doppler ultrasound while shortening the scan time to 13 seconds. High temporal-resolution undersampled TCR was also compared lower temporal-resolution, more highly sampled, regridding in three normal volunteers. CONCLUSION: TCR proved to be an effective method for reconstructing undersampled radial PC data. Although TCR utilizes a temporal constraint, temporal blurring was minimized by using appropriate constraint weights in addition to a spatially varying temporal constraint. TCR allowed for the acquisition time to be reduced to the duration of a breath-hold, while still resulting in accurate velocity measurements.J. Magn. Reson. Imaging 2013;00:000-000. © 2013 Wiley Periodicals, Inc.
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Randomized clinical trial of vitamin D3 doses on prostatic vitamin D metabolite levels and ki67 labeling in prostate cancer patients.
J. Clin. Endocrinol. Metab.
PUBLISHED: 03-05-2013
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Vitamin D3 might benefit prostate cancer (PCa) patients because prostate cells can locally synthesize the active hormone calcitriol.
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Assessing phospholipase A2 activity toward cardiolipin by mass spectrometry.
PLoS ONE
PUBLISHED: 02-13-2013
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Cardiolipin, a major component of mitochondria, is critical for mitochondrial functioning including the regulation of cytochrome c release during apoptosis and proper electron transport. Mitochondrial cardiolipin with its unique bulky amphipathic structure is a potential substrate for phospholipase A2 (PLA2) in vivo. We have developed mass spectrometric methodology for analyzing PLA2 activity toward various cardiolipin forms and demonstrate that cardiolipin is a substrate for sPLA2, cPLA2 and iPLA2, but not for Lp-PLA2. Our results also show that none of these PLA2s have significant PLA1 activities toward dilyso-cardiolipin. To understand the mechanism of cardiolipin hydrolysis by PLA2, we also quantified the release of monolyso-cardiolipin and dilyso-cardiolipin in the PLA2 assays. The sPLA2s caused an accumulation of dilyso-cardiolipin, in contrast to iPLA2 which caused an accumulation of monolyso-cardiolipin. Moreover, cardiolipin inhibits iPLA2 and cPLA2, and activates sPLA2 at low mol fractions in mixed micelles of Triton X-100 with the substrate 1-palmitoyl-2-arachidonyl-sn-phosphtidylcholine. Thus, cardiolipin functions as both a substrate and a regulator of PLA2 activity and the ability to assay the various forms of PLA2 is important in understanding its function.
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Diffusion tensor imaging of extraocular muscle using two-dimensional single-shot interleaved multiple inner volume imaging diffusion-weighted EPI at 3 tesla.
J Magn Reson Imaging
PUBLISHED: 02-05-2013
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To evaluate the feasibility of diffusion tensor imaging (DTI) for the medial and lateral rectus extraocular muscle (EOM) evaluation, to investigate the normal DTI parameters of the medial and lateral rectus EOM, and to compare with other skeletal muscle.
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Systematic analysis of rat 12/15-lipoxygenase enzymes reveals critical role for spinal eLOX3 hepoxilin synthase activity in inflammatory hyperalgesia.
FASEB J.
PUBLISHED: 02-04-2013
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Previously, we observed significant increases in spinal 12-lipoxygenase (LOX) metabolites, in particular, hepoxilins, which contribute to peripheral inflammation-induced tactile allodynia. However, the enzymatic sources of hepoxilin synthase (HXS) activity in rats remain elusive. Therefore, we overexpressed each of the 6 rat 12/15-LOX enzymes in HEK-293T cells and measured by LC-MS/MS the formation of HXB3, 12-HETE, 8-HETE, and 15-HETE from arachidonic acid (AA) at baseline and in the presence of LOX inhibitors (NDGA, AA-861, CDC, baicalein, and PD146176) vs. vehicle-treated and mock-transfected controls. We detected the following primary intrinsic activities: 12-LOX (Alox12, Alox15), 15-LOX (Alox15b), and HXS (Alox12, Alox15). Similar to human and mouse orthologs, proteins encoded by rat Alox12b and Alox12e possessed minimal 12-LOX activity with AA as substrate, while eLOX3 (encoded by Aloxe3) exhibited HXS without 12-LOX activity when coexpressed with Alox12b or supplemented with 12-HpETE. CDC potently inhibited HXS and 12-LOX activity in vitro (relative IC50s: CDC, ~0.5 and 0.8 ?M, respectively) and carrageenan-evoked tactile allodynia in vivo. Notably, peripheral inflammation significantly increased spinal eLOX3; intrathecal pretreatment with either siRNA targeting Aloxe3 or an eLOX3-selective antibody attenuated the associated allodynia. These findings implicate spinal eLOX3-mediated hepoxilin synthesis in inflammatory hyperesthesia and underscore the importance of developing more selective 12-LOX/HXS inhibitors.
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Circulating breast tumor cells exhibit dynamic changes in epithelial and mesenchymal composition.
Science
PUBLISHED: 02-02-2013
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Epithelial-mesenchymal transition (EMT) of adherent epithelial cells to a migratory mesenchymal state has been implicated in tumor metastasis in preclinical models. To investigate its role in human cancer, we characterized EMT in circulating tumor cells (CTCs) from breast cancer patients. Rare primary tumor cells simultaneously expressed mesenchymal and epithelial markers, but mesenchymal cells were highly enriched in CTCs. Serial CTC monitoring in 11 patients suggested an association of mesenchymal CTCs with disease progression. In an index patient, reversible shifts between these cell fates accompanied each cycle of response to therapy and disease progression. Mesenchymal CTCs occurred as both single cells and multicellular clusters, expressing known EMT regulators, including transforming growth factor (TGF)-? pathway components and the FOXC1 transcription factor. These data support a role for EMT in the blood-borne dissemination of human breast cancer.
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Determination of peak deflections from human surrogates using chestbands in side impact tests.
Med Eng Phys
PUBLISHED: 01-26-2013
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To understand the biomechanics of the human body in motor vehicle environments, physical models including anthropomorphic test devices (ATD) and biological models (postmortem human surrogates) are used, and sled tests are conducted. Deflection is often used as a biomechanical variable to characterize the effects of impact loading and derive injury criteria. The objective of the present study was to evaluate different techniques and recommend a methodology to determine the peak thorax and abdominal deflections from temporal contours using chestbands in oblique lateral impacts. The side impact ATD WorldSID representing human surrogates was positioned on a seat. The seat was rigidly fixed to the platform of an acceleration sled. The oblique load-wall fixed to the sled consisted of separate and adjustable plates to contact the shoulder, thorax, abdomen, and pelvis. Two 59-gage chestbands were wrapped on the thorax and abdomen. Tests were conducted at low, medium, and high velocities (3.4, 6.7, and 7.5m/s) and three methods, termed the spine-sternum, bilateral, and spine-box, were used to determine the global peak deflection and its angulation. Results indicated that all three methods produced very similar angulations, for all velocity tests, and at both thorax and abdominal regions. However, maximum deflections were the lowest in the spine-sternum, followed by bilateral and spine-box methods, with one exception. Based on the development of deflection contours, locations used in the definitions of the origin, and accuracy in identifying critical locations/points in time-varying contours, results of the present study indicate that the bilateral method is the optimum procedure to determine the oblique peak deflection vector in biomechanical tests.
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A 3 T sodium and proton composite array breast coil.
Magn Reson Med
PUBLISHED: 01-18-2013
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The objective of this study was to determine whether a sodium phased array would improve sodium breast MRI at 3 T. The secondary objective was to create acceptable proton images with the sodium phased array in place.
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Fluoroketone inhibition of Ca(2+)-independent phospholipase A2 through binding pocket association defined by hydrogen/deuterium exchange and molecular dynamics.
J. Am. Chem. Soc.
PUBLISHED: 01-16-2013
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The mechanism of inhibition of group VIA Ca(2+)-independent phospholipase A(2) (iPLA(2)) by fluoroketone (FK) ligands is examined by a combination of deuterium exchange mass spectrometry (DXMS) and molecular dynamics (MD). Models for iPLA(2) were built by homology with the known structure of patatin and equilibrated by extensive MD simulations. Empty pockets were identified during the simulations and studied for their ability to accommodate FK inhibitors. Ligand docking techniques showed that the potent inhibitor 1,1,1,3-tetrafluoro-7-phenylheptan-2-one (PHFK) forms favorable interactions inside an active-site pocket, where it blocks the entrance of phospholipid substrates. The polar fluoroketone headgroup is stabilized by hydrogen bonds with residues Gly486, Gly487, and Ser519. The nonpolar aliphatic chain and aromatic group are stabilized by hydrophobic contacts with Met544, Val548, Phe549, Leu560, and Ala640. The binding mode is supported by DXMS experiments showing an important decrease of deuteration in the contact regions in the presence of the inhibitor. The discovery of the precise binding mode of FK ligands to the iPLA(2) should greatly improve our ability to design new inhibitors with higher potency and selectivity.
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Toward real-time availability of 3D temperature maps created with temporally constrained reconstruction.
Magn Reson Med
PUBLISHED: 01-15-2013
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PURPOSE: To extend the previously developed temporally constrained reconstruction (TCR) algorithm to allow for real-time availability of three-dimensional (3D) temperature maps capable of monitoring MR-guided high intensity focused ultrasound applications. METHODS: A real-time TCR (RT-TCR) algorithm is developed that only uses current and previously acquired undersampled k-space data from a 3D segmented EPI pulse sequence, with the image reconstruction done in a graphics processing unit implementation to overcome computation burden. Simulated and experimental data sets of HIFU heating are used to evaluate the performance of the RT-TCR algorithm. RESULTS: The simulation studies demonstrate that the RT-TCR algorithm has subsecond reconstruction time and can accurately measure HIFU-induced temperature rises of 20°C in 15 s for 3D volumes of 16 slices (RMSE = 0.1°C), 24 slices (RMSE = 0.2°C), and 32 slices (RMSE = 0.3°C). Experimental results in ex vivo porcine muscle demonstrate that the RT-TCR approach can reconstruct temperature maps with 192 × 162 × 66 mm 3D volume coverage, 1.5 × 1.5 × 3.0 mm resolution, and 1.2-s scan time with an accuracy of ±0.5°C. CONCLUSION: The RT-TCR algorithm offers an approach to obtaining large coverage 3D temperature maps in real-time for monitoring MR-guided high intensity focused ultrasound treatments. Magn Reson Med, 2013. © 2013 Wiley Periodicals, Inc.
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New head gradient coil design and construction techniques.
J Magn Reson Imaging
PUBLISHED: 01-11-2013
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To design and build a head insert gradient coil to use in conjunction with body gradients for superior imaging.
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Polyoxygenated Cholesterol Ester Hydroperoxide Activates TLR4 and SYK Dependent Signaling in Macrophages.
PLoS ONE
PUBLISHED: 01-01-2013
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Oxidation of low-density lipoprotein (LDL) is one of the major causative mechanisms in the development of atherosclerosis. In previous studies, we showed that minimally oxidized LDL (mmLDL) induced inflammatory responses in macrophages, macropinocytosis and intracellular lipid accumulation and that oxidized cholesterol esters (OxCEs) were biologically active components of mmLDL. Here we identified a specific OxCE molecule responsible for the biological activity of mmLDL and characterized signaling pathways in macrophages in response to this OxCE. Using liquid chromatography - tandem mass spectrometry and biological assays, we identified an oxidized cholesteryl arachidonate with bicyclic endoperoxide and hydroperoxide groups (BEP-CE) as a specific OxCE that activates macrophages in a TLR4/MD-2-dependent manner. BEP-CE induced TLR4/MD-2 binding and TLR4 dimerization, phosphorylation of SYK, ERK1/2, JNK and c-Jun, cell spreading and uptake of dextran and native LDL by macrophages. The enhanced macropinocytosis resulted in intracellular lipid accumulation and macrophage foam cell formation. Bone marrow-derived macrophages isolated from TLR4 and SYK knockout mice did not respond to BEP-CE. The presence of BEP-CE was demonstrated in human plasma and in the human plaque material captured in distal protection devices during percutaneous intervention. Our results suggest that BEP-CE is an endogenous ligand that activates the TLR4/SYK signaling pathway. Because BEP-CE is present in human plasma and human atherosclerotic lesions, BEP-CE-induced and TLR4/SYK-mediated macrophage responses may contribute to chronic inflammation in human atherosclerosis.
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Essential role of ELOVL4 protein in very long chain fatty acid synthesis and retinal function.
J. Biol. Chem.
PUBLISHED: 12-24-2011
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Very long chain polyunsaturated fatty acid (VLC-PUFA)-containing glycerophospholipids are highly enriched in the retina; however, details regarding the specific synthesis and function of these highly unusual retinal glycerophospholipids are lacking. Elongation of very long chain fatty acids-4 (ELOVL4) has been identified as a fatty acid elongase protein involved in the synthesis of VLC-PUFAs. Mutations in ELOVL4 have also been implicated in an autosomal dominant form of Stargardt disease (STGD3), a type of juvenile macular degeneration. We have generated photoreceptor-specific conditional knock-out mice and used high performance liquid chromatography-mass spectrometry (HPLC-MS) to examine and analyze the fatty acid composition of retinal membrane glycerophosphatidylcholine and glycerophosphatidylethanolamine species. We also used immunofluorescent staining and histology coupled with electrophysiological data to assess retinal morphology and visual response. The conditional knock-out mice showed a significant decrease in retinal glycerophospholipids containing VLC-PUFAs, specifically contained in the sn-1 position of glycerophosphatidylcholine, implicating the role of Elovl4 in their synthesis. Conditional knock-out mice were also found to have abnormal accumulation of lipid droplets and lipofuscin-like granules while demonstrating photoreceptor-specific abnormalities in visual response, indicating the critical role of Elovl4 for proper rod or cone photoreceptor function. Altogether, this study demonstrates the essential role of ELOVL4 in VLC-PUFA synthesis and retinal function.
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Demographics, Velocity Distributions, and Impact Type as Predictors of AIS 4+ Head Injuries in Motor Vehicle Crashes.
Ann Adv Automot Med
PUBLISHED: 11-23-2011
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The objective of the study was to determine differences between the United States-based NASS and CIREN and Australia-based ANCIS databases in occupant-, crash-, and vehicle-related parameters for AIS 4+ head injuries in motor vehicle crashes. Logistic regression analysis was performed to examine roles of the change in velocity (DV), crash type (frontal, far-side, nearside, rear impact), seatbelt use, and occupant position, gender, age, stature, and body mass in cranial traumas. Belted and unbelted non-ejected occupant (age >16 years) data from 1997-2006 were used for the NASS and CIREN datasets, and 2000-2010 for ANCIS. Vehicle model year, and occupant position and demographics including body mass index (BMI) data were obtained. Injuries were coded using AIS 1990-1998 update. Similarities were apparent across all databases: mean demographics were close to the mid-size anthropometry, mean BMI was in the normal to overweight range, and representations of extreme variations were uncommon. Side impacts contributed to over one-half of the ensemble, implying susceptibility to head trauma in this mode. Odds of sustaining head injury increased by 4% per unit increase in DV (OR: 1.04, 95% CI: 1.03-1.04, p<0.001; adjusted for other variables); one-half for belted compared to unbelted occupants (OR: 0.48, 95% CI: 0.37-0.61, p<0.001); nearside, then far-side had significantly higher odds than frontal, and no difference by gender or position (front-left, front-right). Similar crash- and occupant-related outcomes from the two continents indicate a worldwide need to revise the translation acceleration-based head injury criterion to include the angular component in an appropriate format for improved injury assessment and mitigation.
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Comparison of head-neck responses in frontal impacts using restrained human surrogates.
Ann Adv Automot Med
PUBLISHED: 11-23-2011
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The objective of the study was to evaluate the head and neck kinetics of three-point belted Hybrid III dummy and Test Device for Human Occupant Restraint (THOR) in frontal impacts, and compare their responses with data from post mortem human subjects (PMHS). Surrogates were placed on a buck, capable of accommodating different anthropometry with similar initial positioning. Duplicate tests were conducted at low, medium, and high (3.6, 6.9, and 15.8 m/s) velocities. Upper and lower neck forces and moments were determined from load cell measures and its locations with respect to the ends of the neck. Head excursion-time responses were more repeatable in the Hybrid III dummy than the THOR dummy. Hybrid III dummy response was more rigid in the sagittal plane. Peak THOR motions were closer to PMHS. Based on times of occurrences of peak excursions, THOR was closer to PMHS at all velocities, while Hybrid III dummy showed biofidelity at the medium and high velocities. Controlled positioning and testing with different surrogates provide an evaluation of inter-subject responses. THOR was more likely to "get the head where and when it needs to be" in frontal impacts. With the importance of testing at lower speeds due to recent recognition of real-world injuries, these data suggest that THOR may be an optimal dummy for frontal impacts. Comparisons of head-neck kinetic data with PMHS are valuable in frontal impact injury assessments.
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Lateral neck injury assessments in side impact using post mortem human subject tests.
Ann Adv Automot Med
PUBLISHED: 11-23-2011
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Current neck injury criteria are based on matching upper cervical spine injuries from piglet tests to airbag deployment loads and pairing kinematics from child dummies. These "child-based" scaled data together with adult human cadaver tolerances in axial loading are used to specify neck injury thresholds in axial compression and tension, and flexion and extension moment about the occipital condyles; no thresholds are specified for any other force or moment including lateral bending. The objective of this study was to develop a testing methodology and to determine the lateral bending moment injury threshold under coronal loading. Post mortem human subjects (PMHS) were used. Specimens consisted of whole body and isolated head-neck complexes with intact musculature. Intact specimen positioning included: sitting PMHS upright on a rigid seat, supporting the torso by a plate, maintaining Frankfurt plane horizontal. Isolated head-neck complexes were fixed at T1 with the occiput connected via a custom apparatus to a testing device to induce lateral bending motion. Head angular and linear accelerations and angular velocities were computed using a pyramid nine accelerometer package on the head; specimen-specific physical properties including center of gravity and moments of inertia in the three-dimensions; and equations of equilibrium. These data were used to determine neck loads at the occipital condyles. No specimens sustained injuries, identified by palpation, x-rays, CT, and autopsy. Results from 24 tests indicated that PMHS head-neck complexes can tolerate 75 Nm of coronal moment at low axial load without failure, and this level may be used as an initial estimate of the injury reference value under lateral loading to the human head-neck complex.
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Injury differences between small and large overlap frontal crashes.
Ann Adv Automot Med
PUBLISHED: 11-23-2011
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Because small overlap impacts have recently emerged as a crash mode posing great injury risk to occupants, a detailed analysis of US crash data was conducted using the NASS/CDS and CIREN databases. Frontal crashes were subcategorized into small overlap impact (SOI) and large overlap impact (LOI) using crash and crush characteristics from the datasets. Injuries to head, spine, chest, hip and pelvis, and lower extremities were parsed and compared between crash types. MAIS 3+ occupants in NASS/CDS and CIREN demonstrated increased incidence of head, chest, spine, and hip/pelvis injuries in SOI compared to LOI. In NASS/CDS, subgaleal hematoma represented 48.6% of SOI head injury codes but 27.6% in LOI. Cervical spine posterior element fractures also represented greater proportions of SOI spine injuries (e.g., facet fractures: 27.8 vs. 14.0%), and proximal femur fractures represented a greater proportion of hip/pelvis injuries (e.g., intertrochanteric fracture: 32.5 vs. 11.8%). Tarsal/metatarsal fractures were a lesser proportion of lower extremity injuries in SOI compared to LOI. Occupant contact points inducing these injuries were observed in CIREN cases in some instances without compartment intrusion. These injuries suggest the substantial role of occupant kinematics in SOI which may induce suboptimal occupant restraint interaction.
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Medical record and imaging evaluation to identify arterial tortuosity phenotype in populations at risk for intracranial aneurysms.
AMIA Annu Symp Proc
PUBLISHED: 10-22-2011
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High arterial tortuosity may signify early arterial pathology which may precede development of intracranial aneurysms. We measured arterial tortuosity of intracranial vessels and reviewed the medical records of three groups of patients: with intracranial aneurysms, without aneurysms but at increased clinical risk, and controls without aneurysms or associated risk factors. There was significant but inconsistent evidence of increased arterial tortuosity in aneurysm cases and high-risk cases across different arteries. Medical records review identified that a subset of aneurysm cases carried a diagnosis of Loeys-Dietz syndrome that is often misdiagnosed as Marfan syndrome. We found increased arterial tortuosity in the Loeys-Dietz syndrome cases. A combination of medical record screening for Marfan syndrome or Loeys-Dietz symptoms such as aneurysms and evaluation of arterial tortuosity by a curve of scores from medical images may identify previously undiagnosed cases of Loeys-Dietz syndrome.
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Validation of an arterial tortuosity measure with application to hypertension collection of clinical hypertensive patients.
BMC Bioinformatics
PUBLISHED: 10-18-2011
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Hypertension may increase tortuosity or twistedness of arteries. We applied a centerline extraction algorithm and tortuosity metric to magnetic resonance angiography (MRA) brain images to quantitatively measure the tortuosity of arterial vessel centerlines. The most commonly used arterial tortuosity measure is the distance factor metric (DFM). This study tested a DFM based measurements ability to detect increases in arterial tortuosity of hypertensives using existing images. Existing images presented challenges such as different resolutions which may affect the tortuosity measurement, different depths of the area imaged, and different artifacts of imaging that require filtering.
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The effect of electronically steering a phased array ultrasound transducer on near-field tissue heating.
Med Phys
PUBLISHED: 10-08-2011
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This study presents the results obtained from both simulation and experimental techniques that show the effect of mechanically or electronically steering a phased array transducer on proximal tissue heating.
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What is Visualize?

JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

How does it work?

We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.

Video X seems to be unrelated to Abstract Y...

In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.