1
|
Generalized super-resolution 4D Flow MRI $\unicode{x2013}$ using ensemble learning to extend across the cardiovascular system. ARXIV 2023:arXiv:2311.11819v2. [PMID: 38045482 PMCID: PMC10690302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
4D Flow Magnetic Resonance Imaging (4D Flow MRI) is a non-invasive measurement technique capable of quantifying blood flow across the cardiovascular system. While practical use is limited by spatial resolution and image noise, incorporation of trained super-resolution (SR) networks has potential to enhance image quality post-scan. However, these efforts have predominantly been restricted to narrowly defined cardiovascular domains, with limited exploration of how SR performance extends across the cardiovascular system; a task aggravated by contrasting hemodynamic conditions apparent across the cardiovasculature. The aim of our study was to explore the generalizability of SR 4D Flow MRI using a combination of heterogeneous training sets and dedicated ensemble learning. With synthetic training data generated across three disparate domains (cardiac, aortic, cerebrovascular), varying convolutional base and ensemble learners were evaluated as a function of domain and architecture, quantifying performance on both in-silico and acquired in-vivo data from the same three domains. Results show that both bagging and stacking ensembling enhance SR performance across domains, accurately predicting high-resolution velocities from low-resolution input data in-silico. Likewise, optimized networks successfully recover native resolution velocities from downsampled in-vivo data, as well as show qualitative potential in generating denoised SR-images from clinical level input data. In conclusion, our work presents a viable approach for generalized SR 4D Flow MRI, with ensemble learning extending utility across various clinical areas of interest.
Collapse
|
2
|
Measurement of the Positive Muon Anomalous Magnetic Moment to 0.20 ppm. PHYSICAL REVIEW LETTERS 2023; 131:161802. [PMID: 37925710 DOI: 10.1103/physrevlett.131.161802] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 09/05/2023] [Indexed: 11/07/2023]
Abstract
We present a new measurement of the positive muon magnetic anomaly, a_{μ}≡(g_{μ}-2)/2, from the Fermilab Muon g-2 Experiment using data collected in 2019 and 2020. We have analyzed more than 4 times the number of positrons from muon decay than in our previous result from 2018 data. The systematic error is reduced by more than a factor of 2 due to better running conditions, a more stable beam, and improved knowledge of the magnetic field weighted by the muon distribution, ω[over ˜]_{p}^{'}, and of the anomalous precession frequency corrected for beam dynamics effects, ω_{a}. From the ratio ω_{a}/ω[over ˜]_{p}^{'}, together with precisely determined external parameters, we determine a_{μ}=116 592 057(25)×10^{-11} (0.21 ppm). Combining this result with our previous result from the 2018 data, we obtain a_{μ}(FNAL)=116 592 055(24)×10^{-11} (0.20 ppm). The new experimental world average is a_{μ}(exp)=116 592 059(22)×10^{-11} (0.19 ppm), which represents a factor of 2 improvement in precision.
Collapse
|
3
|
Comprehensive Analysis of Scientific Output in Hip and Knee Arthroscopy. ACTA CHIRURGIAE ORTHOPAEDICAE ET TRAUMATOLOGIAE CECHOSLOVACA 2023; 90:233-238. [PMID: 37690036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
PURPOSE OF THE STUDY A global bibliometric comparison of the level of scientific interest and output in the two research areas hip and knee arthroscopy (H-ASC and K-ASC) was carried out. In addition, the different degrees of publication activity in the countries and institutes performing this research were investigated. MATERIAL AND METHODS Publications from 1945-2020 listed in the Web of Science Core Collection were included in the study. Using the web application Science Performance Evaluation (SciPE), quantitative and qualitative aspects were evaluated. Subsequently, the date of publication, author information, and other metadata were analysed. RESULTS Since 1945, 3,924 studies have been published on K-ASC and 2,163 on H-ASC. The majority of the publications which have appeared since 2016 dealt with the topic of H-ASC (H-ASC: 241.2 publications/year; K-ASC: 217.4 publications/year). The USA published the most on both topics (H-ASC: 1,123 publications; K-ASC: 1,078 publications). More countries and institutes participated in K-ASC (3,008 institutes, 82 countries) than in H-ASC (103 institutes, 57 countries). The ten institutes with the most publications accounted for 36.71% and 12.34% of all publications on H-ASC and K-ASC, respectively. H-ASC received 78.12% of its funding from private sponsors while K-ASC was supported mainly by governmental/nonprofit sponsors (70.92%). CONCLUSIONS This study provides the first scientific comparison between H-ASC and K-ASC. Measured by qualitative and quantitative aspects, K-ASC was the most flourishing research area overall. In the last ten to five years, interest has shifted towards HASC with an increasing number of publications and a higher rate of citations. Key words: knee arthroscopy, hip arthroscopy, bibliometric comparison.
Collapse
|
4
|
Measurement of the Positive Muon Anomalous Magnetic Moment to 0.46 ppm. PHYSICAL REVIEW LETTERS 2021; 126:141801. [PMID: 33891447 DOI: 10.1103/physrevlett.126.141801] [Citation(s) in RCA: 111] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Accepted: 03/25/2021] [Indexed: 06/12/2023]
Abstract
We present the first results of the Fermilab National Accelerator Laboratory (FNAL) Muon g-2 Experiment for the positive muon magnetic anomaly a_{μ}≡(g_{μ}-2)/2. The anomaly is determined from the precision measurements of two angular frequencies. Intensity variation of high-energy positrons from muon decays directly encodes the difference frequency ω_{a} between the spin-precession and cyclotron frequencies for polarized muons in a magnetic storage ring. The storage ring magnetic field is measured using nuclear magnetic resonance probes calibrated in terms of the equivalent proton spin precession frequency ω[over ˜]_{p}^{'} in a spherical water sample at 34.7 °C. The ratio ω_{a}/ω[over ˜]_{p}^{'}, together with known fundamental constants, determines a_{μ}(FNAL)=116 592 040(54)×10^{-11} (0.46 ppm). The result is 3.3 standard deviations greater than the standard model prediction and is in excellent agreement with the previous Brookhaven National Laboratory (BNL) E821 measurement. After combination with previous measurements of both μ^{+} and μ^{-}, the new experimental average of a_{μ}(Exp)=116 592 061(41)×10^{-11} (0.35 ppm) increases the tension between experiment and theory to 4.2 standard deviations.
Collapse
|
5
|
Simultaneous measurements of 3D wall shear stress and pulse wave velocity in the murine aortic arch. J Cardiovasc Magn Reson 2021; 23:34. [PMID: 33731147 PMCID: PMC7972216 DOI: 10.1186/s12968-021-00725-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 02/03/2021] [Indexed: 11/16/2022] Open
Abstract
PURPOSE Wall shear stress (WSS) and pulse wave velocity (PWV) are important parameters to characterize blood flow in the vessel wall. Their quantification with flow-sensitive phase-contrast (PC) cardiovascular magnetic resonance (CMR), however, is time-consuming. Furthermore, the measurement of WSS requires high spatial resolution, whereas high temporal resolution is necessary for PWV measurements. For these reasons, PWV and WSS are challenging to measure in one CMR session, making it difficult to directly compare these parameters. By using a retrospective approach with a flexible reconstruction framework, we here aimed to simultaneously assess both PWV and WSS in the murine aortic arch from the same 4D flow measurement. METHODS Flow was measured in the aortic arch of 18-week-old wildtype (n = 5) and ApoE-/- mice (n = 5) with a self-navigated radial 4D-PC-CMR sequence. Retrospective data analysis was used to reconstruct the same dataset either at low spatial and high temporal resolution (PWV analysis) or high spatial and low temporal resolution (WSS analysis). To assess WSS, the aortic lumen was labeled by semi-automatically segmenting the reconstruction with high spatial resolution. WSS was determined from the spatial velocity gradients at the lumen surface. For calculation of the PWV, segmentation data was interpolated along the temporal dimension. Subsequently, PWV was quantified from the through-plane flow data using the multiple-points transit-time method. Reconstructions with varying frame rates and spatial resolutions were performed to investigate the influence of spatiotemporal resolution on the PWV and WSS quantification. RESULTS 4D flow measurements were conducted in an acquisition time of only 35 min. Increased peak flow and peak WSS values and lower errors in PWV estimation were observed in the reconstructions with high temporal resolution. Aortic PWV was significantly increased in ApoE-/- mice compared to the control group (1.7 ± 0.2 versus 2.6 ± 0.2 m/s, p < 0.001). Mean WSS magnitude values averaged over the aortic arch were (1.17 ± 0.07) N/m2 in wildtype mice and (1.27 ± 0.10) N/m2 in ApoE-/- mice. CONCLUSION The post processing algorithm using the flexible reconstruction framework developed in this study permitted quantification of global PWV and 3D-WSS in a single acquisition. The possibility to assess both parameters in only 35 min will markedly improve the analyses and information content of in vivo measurements.
Collapse
|
6
|
Evaluation of Plaque Characteristics and Inflammation Using Magnetic Resonance Imaging. Biomedicines 2021; 9:185. [PMID: 33673124 PMCID: PMC7917750 DOI: 10.3390/biomedicines9020185] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2021] [Revised: 02/08/2021] [Accepted: 02/09/2021] [Indexed: 12/19/2022] Open
Abstract
Atherosclerosis is an inflammatory disease of large and medium-sized arteries, characterized by the growth of atherosclerotic lesions (plaques). These plaques often develop at inner curvatures of arteries, branchpoints, and bifurcations, where the endothelial wall shear stress is low and oscillatory. In conjunction with other processes such as lipid deposition, biomechanical factors lead to local vascular inflammation and plaque growth. There is also evidence that low and oscillatory shear stress contribute to arterial remodeling, entailing a loss in arterial elasticity and, therefore, an increased pulse-wave velocity. Although altered shear stress profiles, elasticity and inflammation are closely intertwined and critical for plaque growth, preclinical and clinical investigations for atherosclerosis mostly focus on the investigation of one of these parameters only due to the experimental limitations. However, cardiovascular magnetic resonance imaging (MRI) has been demonstrated to be a potent tool which can be used to provide insights into a large range of biological parameters in one experimental session. It enables the evaluation of the dynamic process of atherosclerotic lesion formation without the need for harmful radiation. Flow-sensitive MRI provides the assessment of hemodynamic parameters such as wall shear stress and pulse wave velocity which may replace invasive and radiation-based techniques for imaging of the vascular function and the characterization of early plaque development. In combination with inflammation imaging, the analyses and correlations of these parameters could not only significantly advance basic preclinical investigations of atherosclerotic lesion formation and progression, but also the diagnostic clinical evaluation for early identification of high-risk plaques, which are prone to rupture. In this review, we summarize the key applications of magnetic resonance imaging for the evaluation of plaque characteristics through flow sensitive and morphological measurements. The simultaneous measurements of functional and structural parameters will further preclinical research on atherosclerosis and has the potential to fundamentally improve the detection of inflammation and vulnerable plaques in patients.
Collapse
|
7
|
Rapid T1rho dispersion imaging for improved characterization of myocardial tissue using synthetic dispersion reconstruction. Eur Heart J 2020. [DOI: 10.1093/ehjci/ehaa946.0201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Introduction
Over the past decade, CMRI has become the method of choice for characterizing fibrotic scars. Native T1ρ mapping offers an alternative to conventional T1 and T2 quantification techniques due to its high sensitivity to low-frequency processes. In addition, there is the possibility of T1ρ dispersion imaging, which could be used as a sensitive biomarker for assessing myocardial fibrosis [1]. However, due to a very long measurement time, T1ρ dispersion quantification in myocardium can hardly be done in the limited time of a small animal study. In this work we present a concept for rapid T1ρ dispersion quantification based on the new approach of synthetic dispersion reconstruction (SynDR).
Theory
A T1ρ map is calculated by measuring Nt T1ρ weighted images using different spin lock (SL) times. T1ρ dispersion quantification requires Nf T1ρ maps with different SL amplitudes. Hence the measurement time is very time consuming, because it requires the acquisition of Nt*Nf images (full mapping). With our new approach (SynDR), only a single T1ρ reference map and a series of dispersion weighted images need to be acquired. The T1ρ dispersion can be reconstructed by synthetically generated maps, whereby each map is calculated from the reference map and the dispersion weighted images, only requiring Nt+Nf images.
Methods
All measurements were performed on a 7T small animal scanner. The method was based on an optional cartesian/radial gradient echo sequence using large flip angles (45°) and an optimized readout sorting. The quantification accuracy of SynDR was compared with full mapping measurements in a phantom experiment and validated in vivo on mice. The synthetic T1ρ maps were used to perform a dispersion analysis in myocardium.
Results
The comparison between SynDR and the full mapping reference in phantoms showed a very high quantification accuracy with a mean/maximum deviation of 1.1% and 1.7%. Fig. 1 shows synthetic T1ρ maps (a) in healthy mice and the obtained dispersion map (b) using SynDR. In the dispersion analysis (c) a T1ρ slope of 5.6±1.5ms/kHz was obtained for myocardium. Here an acceleration factor of 4 could be realized in comparison to full mapping. In further measurements, an acceleration of 7.4 could be reached using a radial readout with KWIC filter view sharing.
Discussion
In this work, a novel T1ρ dispersion imaging method was presented that far exceeds the speed of conventional full mapping methods. The acceleration is based on avoiding unnecessary measurements of T1ρ weighted images through more efficient mathematical modeling. Further acceleration could be achieved using an optimized radial data acquisition. The method shows good image quality and high quantification accuracy both in phantom and in vivo. Based on the promising results, further studies in mice are planned to investigate the dispersion character of healthy and diseased tissues.
Reference
[1] Yin Q et al. Magn Reson Imaging. 2017 Oct; 42:69–73.
SynDR method and T1ρ dispersion analysis
Funding Acknowledgement
Type of funding source: Public grant(s) – National budget only. Main funding source(s): BRD, Bundesministerium für Bildung und Forschung
Collapse
|
8
|
Should Data Structures Look Flat for End Users? INFORMATION SYSTEMS MANAGEMENT 2020. [DOI: 10.1080/10580530.2020.1731883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
|
9
|
Fast self-navigated wall shear stress measurements in the murine aortic arch using radial 4D-phase contrast cardiovascular magnetic resonance at 17.6 T. J Cardiovasc Magn Reson 2019; 21:64. [PMID: 31610777 PMCID: PMC6792269 DOI: 10.1186/s12968-019-0566-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Accepted: 07/23/2019] [Indexed: 11/10/2022] Open
Abstract
PURPOSE 4D flow cardiovascular magnetic resonance (CMR) and the assessment of wall shear stress (WSS) are non-invasive tools to study cardiovascular risks in vivo. Major limitations of conventional triggered methods are the long measurement times needed for high-resolution data sets and the necessity of stable electrocardiographic (ECG) triggering. In this work an ECG-free retrospectively synchronized method is presented that enables accelerated high-resolution measurements of 4D flow and WSS in the aortic arch of mice. METHODS 4D flow and WSS were measured in the aortic arch of 12-week-old wildtype C57BL/6 J mice (n = 7) with a radial 4D-phase-contrast (PC)-CMR sequence, which was validated in a flow phantom. Cardiac and respiratory motion signals were extracted from the radial CMR signal and were used for the reconstruction of 4D-flow data. Rigid motion correction and a first order B0 correction was used to improve the robustness of magnitude and velocity data. The aortic lumen was segmented semi-automatically. Temporally averaged and time-resolved WSS and oscillatory shear index (OSI) were calculated from the spatial velocity gradients at the lumen surface at 14 locations along the aortic arch. Reproducibility was tested in 3 animals and the influence of subsampling was investigated. RESULTS Volume flow, cross-sectional areas, WSS and the OSI were determined in a measurement time of only 32 min. Longitudinal and circumferential WSS and radial stress were assessed at 14 analysis planes along the aortic arch. The average longitudinal, circumferential and radial stress values were 1.52 ± 0.29 N/m2, 0.28 ± 0.24 N/m2 and - 0.21 ± 0.19 N/m2, respectively. Good reproducibility of WSS values was observed. CONCLUSION This work presents a robust measurement of 4D flow and WSS in mice without the need of ECG trigger signals. The retrospective approach provides fast flow quantification within 35 min and a flexible reconstruction framework.
Collapse
|
10
|
Treatment of discontinuous emission of sewage sludge odours by a full scale biotrickling filter with an activated carbon polishing unit. WATER SCIENCE AND TECHNOLOGY : A JOURNAL OF THE INTERNATIONAL ASSOCIATION ON WATER POLLUTION RESEARCH 2018; 77:2482-2490. [PMID: 29893737 DOI: 10.2166/wst.2018.203] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
A SULPHUSTM biotrickling filter (BTF) and an ACTUSTM polishing activated carbon filter (ACF) were used at a wastewater treatment plant to treat 2,432 m3·h-1 of air extracted from sewage sludge processes. The project is part of Thames Water's strategy to reduce customer odour impact and, in this case, is designed to achieve a maximum discharge concentration of 1,000 ouE·m-3. The odour and hydrogen sulphide concentration in the input air was more influenced by the operation of the sludge holding tank mixers than by ambient temperature. Phosphorus was found to be limiting the performance of the BTF during peak conditions, hence requiring additional nutrient supply. Olfactometry and pollutant measurements demonstrated that during the high rate of change of intermittent odour concentrations the ACF was required to reach compliant stack values. The two stage unit outperformed design criteria, with 139 ouE·m-3 measured after 11 months of operation. At peak conditions and even at very low temperatures, the nutrient addition considerably increased the performance of the BTF, extending the time before activated carbon replacement over the one year design time. During baseline operation, the BTF achieved values between 266-1,647 ouE·m-3 even during a 6 day irrigation failure of the biofilm.
Collapse
|
11
|
Assessment of local pulse wave velocity distribution in mice using k-t BLAST PC-CMR with semi-automatic area segmentation. J Cardiovasc Magn Reson 2017; 19:77. [PMID: 29037199 PMCID: PMC5641989 DOI: 10.1186/s12968-017-0382-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 08/22/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Local aortic pulse wave velocity (PWV) is a measure for vascular stiffness and has a predictive value for cardiovascular events. Ultra high field CMR scanners allow the quantification of local PWV in mice, however these systems are yet unable to monitor the distribution of local elasticities. METHODS In the present study we provide a new accelerated method to quantify local aortic PWV in mice with phase-contrast cardiovascular magnetic resonance imaging (PC-CMR) at 17.6 T. Based on a k-t BLAST (Broad-use Linear Acquisition Speed-up Technique) undersampling scheme, total measurement time could be reduced by a factor of 6. The fast data acquisition enables to quantify the local PWV at several locations along the aortic blood vessel based on the evaluation of local temporal changes in blood flow and vessel cross sectional area. To speed up post processing and to eliminate operator bias, we introduce a new semi-automatic segmentation algorithm to quantify cross-sectional areas of the aortic vessel. The new methods were applied in 10 eight-month-old mice (4 C57BL/6J-mice and 6 ApoE (-/-)-mice) at 12 adjacent locations along the abdominal aorta. RESULTS Accelerated data acquisition and semi-automatic post-processing delivered reliable measures for the local PWV, similiar to those obtained with full data sampling and manual segmentation. No statistically significant differences of the mean values could be detected for the different measurement approaches. Mean PWV values were elevated for the ApoE (-/-)-group compared to the C57BL/6J-group (3.5 ± 0.7 m/s vs. 2.2 ± 0.4 m/s, p < 0.01). A more heterogeneous PWV-distribution in the ApoE (-/-)-animals could be observed compared to the C57BL/6J-mice, representing the local character of lesion development in atherosclerosis. CONCLUSION In the present work, we showed that k-t BLAST PC-MRI enables the measurement of the local PWV distribution in the mouse aorta. The semi-automatic segmentation method based on PC-CMR data allowed rapid determination of local PWV. The findings of this study demonstrate the ability of the proposed methods to non-invasively quantify the spatial variations in local PWV along the aorta of ApoE (-/-)-mice as a relevant model of atherosclerosis.
Collapse
|
12
|
MRI-based quantification of renal perfusion in mice: Improving sensitivity and stability in FAIR ASL. Z Med Phys 2017; 27:334-339. [PMID: 28431859 DOI: 10.1016/j.zemedi.2017.02.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 01/11/2017] [Accepted: 02/06/2017] [Indexed: 11/16/2022]
Abstract
PURPOSE The importance of the orientation of the selective inversion slice in relation to the anatomy in flow-sensitive alternating inversion recovery arterial spin labeling (FAIR ASL) kidney perfusion measurements is demonstrated by comparing the standard FAIR scheme to a scheme with an improved slice selective control experiment. METHODS A FAIR ASL method is used. The selective inversion preparation slice is set perpendicular to the measurement slice to decrease the unintended labeling of arterial spins in the control experiment. A T1*-based quantification method compensates for the effects of the imperfect inversion on the edge of the selective inversion slice. The quantified perfusion values are compared to the standard experiment with parallel orientation of imaging and selective inversion slice. RESULTS Perfusion maps acquired with the perpendicular inversion slice orientation show higher sensitivity compared to the parallel orientation. The T1*-based quantification method removes artifacts arising from imperfect inversion slice profiles. The stability is improved. CONCLUSION Adjusting the labeling technique to the anatomy is of high importance. Improved sensitivity and reproducibility could be demonstrated. The proposed method provides a solution to the problem of FAIR ASL measurements of renal perfusion in coronal view.
Collapse
|
13
|
Local versus global aortic pulse wave velocity in early atherosclerosis: An animal study in ApoE-/--mice using ultrahigh field MRI. PLoS One 2017; 12:e0171603. [PMID: 28207773 PMCID: PMC5313136 DOI: 10.1371/journal.pone.0171603] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2016] [Accepted: 01/23/2017] [Indexed: 11/25/2022] Open
Abstract
Increased aortic stiffness is known to be associated with atherosclerosis and has a predictive value for cardiovascular events. This study aims to investigate the local distribution of early arterial stiffening due to initial atherosclerotic lesions. Therefore, global and local pulse wave velocity (PWV) were measured in ApoE-/- and wild type (WT) mice using ultrahigh field MRI. For quantification of global aortic stiffness, a new multi-point transit-time (TT) method was implemented and validated to determine the global PWV in the murine aorta. Local aortic stiffness was measured by assessing the local PWV in the upper abdominal aorta, using the flow/area (QA) method. Significant differences between age matched ApoE-/- and WT mice were determined for global and local PWV measurements (global PWV: ApoE-/-: 2.7±0.2m/s vs WT: 2.1±0.2m/s, P<0.03; local PWV: ApoE-/-: 2.9±0.2m/s vs WT: 2.2±0.2m/s, P<0.03). Within the WT mouse group, the global PWV correlated well with the local PWV in the upper abdominal aorta (R2 = 0.75, P<0.01), implying a widely uniform arterial elasticity. In ApoE-/- animals, however, no significant correlation between individual local and global PWV was present (R2 = 0.07, P = 0.53), implying a heterogeneous distribution of vascular stiffening in early atherosclerosis. The assessment of global PWV using the new multi-point TT measurement technique was validated against a pressure wire measurement in a vessel phantom and showed excellent agreement. The experimental results demonstrate that vascular stiffening caused by early atherosclerosis is unequally distributed over the length of large vessels. This finding implies that assessing heterogeneity of arterial stiffness by multiple local measurements of PWV might be more sensitive than global PWV to identify early atherosclerotic lesions.
Collapse
|
14
|
Self-navigation under non-steady-state conditions: Cardiac and respiratory self-gating of inversion recovery snapshot FLASH acquisitions in mice. Magn Reson Med 2016; 76:1887-1894. [PMID: 26743137 DOI: 10.1002/mrm.26068] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Revised: 10/06/2015] [Accepted: 11/02/2015] [Indexed: 01/30/2023]
Abstract
PURPOSE An algorithm is presented to enable cardiac and respiratory self-gating in combination with Inversion Recovery Look-Locker read-outs. METHODS A radial inversion recovery snapshot FLASH sequence was adapted for retrospective cardiac T1 measurements in mice. Cardiac and respiratory data were extracted from the k-space center of radial projections and an adapted method for retrospective cardiac synchronization is introduced. Electrocardiogram (ECG) data was acquired concurrently for validation of the proposed self-gating technique. T1 maps generated by the proposed technique were compared with maps reconstructed with the ECG reference. RESULTS Respiratory gating and cardiac trigger points could be obtained for the whole time course of the relaxation dynamic and correlate very well to the ECG signal. T1 maps reconstructed with the self-gating technique are in very good agreement with maps reconstructed with the external reference. CONCLUSION The proposed method extends "wireless" cardiac MRI to non-steady-state inversion recovery measurements. T1 maps were generated with a quality comparable to ECG based reconstructions. As the method does not rely on an ECG trigger signal it provides easier animal handling. Magn Reson Med 76:1887-1894, 2016. © 2016 International Society for Magnetic Resonance in Medicine.
Collapse
|
15
|
On the relevance of reports—Integrating an automated archiving component into a business intelligence system. INTERNATIONAL JOURNAL OF INFORMATION MANAGEMENT 2015. [DOI: 10.1016/j.ijinfomgt.2015.07.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
|
16
|
Quantification of perfusion in murine myocardium: A retrospectively triggered T1 -based ASL method using model-based reconstruction. Magn Reson Med 2014; 74:1705-15. [PMID: 25446550 DOI: 10.1002/mrm.25526] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Revised: 10/06/2014] [Accepted: 10/20/2014] [Indexed: 11/12/2022]
Abstract
PURPOSE A method for the quantification of perfusion in murine myocardium is demonstrated. The method allows for the reconstruction of perfusion maps on arbitrary time points in the heart cycle while addressing problems that arise due to the irregular heart beat of mice. METHODS A flow-sensitive alternating inversion recovery arterial spin labeling method using an untriggered FLASH-read out with random sampling is used. Look-Locker conditions are strictly maintained. No dummy pulses or mechanism to reduce deviation from Look-Locker conditions are needed. Electrocardiogram and respiratory data are recorded for retrospective gating and triggering. A model-based technique is used to reconstruct missing k-space data to cope with the undersampling inherent in retrospectively gated methods. Acquisition and reconstruction were validated numerically and in phantom measurements before in vivo experimentation. RESULTS Quantitative perfusion maps were acquired within a single slice measurement time of 11 min. Perfusion values are in good accordance to literature values. Myocardial infarction could be clearly visualized and results were confirmed with histological results. CONCLUSION The proposed method is capable of producing quantitative perfusion maps on arbitrary positions in the heart cycle within a short measurement time. The method is robust against irregular breathing patterns and heart rate changes and can be implemented on all scanners.
Collapse
|
17
|
494 LPA6 promotes growth and tumorigenicity of hepatocellular carcinoma via activation of PIM-3 proto-oncogene kinase. Eur J Cancer 2014. [DOI: 10.1016/s0959-8049(14)70620-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
|
18
|
Molecular Imaging at Nanoscale with Magnetic Resonance Imaging. Nanomedicine (Lond) 2014. [DOI: 10.1201/b17246-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
|
19
|
Two subgroups of CRLF2-overexpressing pediatric acute lymphoblastic leukemias differ in outcome and gene expression. KLINISCHE PADIATRIE 2014. [DOI: 10.1055/s-0034-1374826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
20
|
Alkalisierung des Harns zur Metaphylaxe bei Kalziumoxalatsteinen: K-Zitrat vs. Na-K-Zitrat. ACTA ACUST UNITED AC 2014. [DOI: 10.1007/s001310050051] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
21
|
A Five-Base-Pair-Deletion in the Gene for the Large Subunit Causes the Lesion in the Ribulose Bisphosphate Carboxylase/Oxygenase-Deficient Plastome Mutant Sigma ofOenothera hookeri. ACTA ACUST UNITED AC 2014. [DOI: 10.1111/j.1438-8677.1988.tb00013.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
22
|
Abstract
The exploitation of DNA polymorphisms by an ever-increasing number of molecular marker technologies has begun to have an impact on plant genome research and breeding. Restriction fragment length polymorphisms, micro- and mini-satellites and PCR-based approaches are used to determine inter- and intra-specific genetic diversity and construct molecular maps of crops using specially designed mapping populations. Resistance genes and other agronomically important loci are tagged with tightly linked DNA markers and the genes isolated by magabase DNA technology and cloning into yeast artificial chromosomes (YAC). This review discusses some recent developments and results in this field.
Collapse
|
23
|
Abstract
Plant genetic engineering has long since left its experimental stage: transgenic plants with resistance to viruses, bacteria, fungi, various pests and abiotic stresses have already been released in their hundreds. Transgenic plants can produce better fruits and food of higher quality than wild-types, and can be used as bioreactors for the synthesis of pharmaceutically important compounds. This review portrays some of the achievements in this field of plant molecular biology.
Collapse
|
24
|
Fast retrospectively triggered local pulse-wave velocity measurements in mice with CMR-microscopy using a radial trajectory. J Cardiovasc Magn Reson 2013; 15:88. [PMID: 24083810 PMCID: PMC3850985 DOI: 10.1186/1532-429x-15-88] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Accepted: 09/03/2013] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND The aortic pulse-wave velocity (PWV) is an important indicator of cardiovascular risk. In recent studies MRI methods have been developed to measure this parameter noninvasively in mice. Present techniques require additional hardware for cardiac and respiratory gating. In this work a robust self-gated measurement of the local PWV in mice without the need of triggering probes is proposed. METHODS The local PWV of 6-months-old wild-type C57BL/6J mice (n=6) was measured in the abdominal aorta with a retrospectively triggered radial Phase Contrast (PC) MR sequence using the flow-area (QA) method. A navigator signal was extracted from the CMR data of highly asymmetric radial projections with short repetition time (TR=3 ms) and post-processed with high-pass and low-pass filters for retrospective cardiac and respiratory gating. The self-gating signal was used for a reconstruction of high-resolution Cine frames of the aortic motion. To assess the local PWV the volume flow Q and the cross-sectional area A of the aorta were determined. The results were compared with the values measured with a triggered Cartesian and an undersampled triggered radial PC-Cine sequence. RESULTS In all examined animals a self-gating signal could be extracted and used for retrospective breath-gating and PC-Cine reconstruction. With the non-triggered measurement PWV values of 2.3±0.2 m/s were determined. These values are in agreement with those measured with the triggered Cartesian (2.4±0.2 m/s) and the triggered radial (2.3±0.2 m/s) measurement. Due to the strong robustness of the radial trajectory against undersampling an acceleration of more than two relative to the prospectively triggered Cartesian sampling could be achieved with the retrospective method. CONCLUSION With the radial flow-encoding sequence the extraction of a self-gating signal is feasible. The retrospective method enables a robust and fast measurement of the local PWV without the need of additional trigger hardware.
Collapse
|
25
|
Myocardial perfusion quantification using the T
1
-based FAIR-ASL method: The influence of heart anatomy, cardiopulmonary blood flow and look-locker readout. Magn Reson Med 2013; 71:1784-97. [DOI: 10.1002/mrm.24843] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2012] [Revised: 05/07/2013] [Accepted: 05/22/2013] [Indexed: 11/11/2022]
|
26
|
Detection of haemophilia A during quality assurance of fresh frozen plasma. Transfus Med 2013; 23:206. [DOI: 10.1111/tme.12019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2012] [Revised: 10/17/2012] [Accepted: 01/30/2013] [Indexed: 11/30/2022]
|
27
|
Genetic diseases and molecular genetics. Nephrol Dial Transplant 2013. [DOI: 10.1093/ndt/gft126] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
|
28
|
Measurement of muon capture on the proton to 1% precision and determination of the pseudoscalar coupling gP. PHYSICAL REVIEW LETTERS 2013; 110:012504. [PMID: 23383785 DOI: 10.1103/physrevlett.110.012504] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2012] [Indexed: 06/01/2023]
Abstract
The MuCap experiment at the Paul Scherrer Institute has measured the rate Λ(S) of muon capture from the singlet state of the muonic hydrogen atom to a precision of 1%. A muon beam was stopped in a time projection chamber filled with 10-bar, ultrapure hydrogen gas. Cylindrical wire chambers and a segmented scintillator barrel detected electrons from muon decay. Λ(S) is determined from the difference between the μ(-) disappearance rate in hydrogen and the free muon decay rate. The result is based on the analysis of 1.2 × 10(10) μ(-) decays, from which we extract the capture rate Λ(S) = (714.9 ± 5.4(stat) ± 5.1(syst)) s(-1) and derive the proton's pseudoscalar coupling g(P)(q(0)(2) = -0.88 m(μ)(2)) = 8.06 ± 0.55.
Collapse
|
29
|
|
30
|
Cardiovascular complications in CKD 5D. Nephrol Dial Transplant 2012. [DOI: 10.1093/ndt/gfs225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
31
|
Trauma Association of Canada Annual Scientific Meeting abstractsErythroopoietin resuscitated with normal saline, Ringer’s lactate and 7.5% hypertonic saline reduces small intestine injury in a hemorrhagic shock and resuscitation rat model.Analgesia in the management of pediatric trauma in the resuscitative phase: the role of the trauma centre.Multidisciplinary trauma team care in Kandahar, Afghanistan: current injury patterns and care practices.Does computed tomography for penetrating renal injury reduce renal exploration? An 8-year review at a Canadian level 1 trauma centre.The other side of pediatric trauma: violence and intent injury.Upregulation of activated protein C leads to factor V deficiency in early trauma coagulopathy.A provincial integrated model of improved care for patients following hip fracture.Sports concussion: an Olympic boxing model comparing sex with biomechanics and traumatic brain injury.A multifaceted quality improvement strategy to optimize monitoring and management of delirium in trauma patients: results of a clinician survey.Risk factors for severe all-terrain vehicle injuries in Alberta.Evaluating potential spatial access to trauma centre care by severely injured patients.Incidence of brain injury in facial fractures.Surgical outcomes and the acute care surgery service.The acute care general surgery population and prognostic factors for morbidity and mortality.Disaster preparedness of trauma.What would you like to know and how can we help you? Assessing the needs of regional trauma centres.Posttraumatic stress disorder screening for trauma patients at a level 1 trauma centre.Physical and finite element model reconstruction of a subdural hematoma event.Abdominal wall reconstruction in the trauma patient with an open abdomen.Development and pilot testing of a survey to measure patient and family experiences with injury care.Occult shock in trauma: What are Canadian traumatologists missing?Timeliness in obtaining emergent percutaneous procedures for the severely injured patient: How long is too long?97% of massive transfusion protocol activations do not include a complete hemorrhage panel.Trauma systems in Canada: What system components facilitate access to definitive care?The role of trauma team leaders in missed injuries: Does specialty matter?The adverse consequences of dabigatran among trauma and acute surgical patients.A descriptive study of bicycle helmet use in Montréal.Factor XIII, desmopressin and permissive hypotension enhance clot formation compared with normotensive resuscitation: uncontrolled hemorrhagic shock model.Negative pressure wound therapy for critically ill adults with open abdominal wounds: a systematic review.The “weekend warrior:” Fact or fiction for major trauma?Canadian injury preventon curriculum: a means to promote injury prevention.Penetrating splenic trauma: Safe for nonoperative management?The pediatric advanced trauma life support course: a national initiative.The effectiveness of a psycho-educational program among outpatients with burns or complex trauma.Trauma centre performance indicators for nonfatal outcomes: a scoping review.The evaluation of short track speed skating helmet performance.Complication rates as a trauma care performance indicator: a systematic review.Unplanned readmission following admission for traumatic injury: When, where and why?Reconstructions of concussive impacts in ice hockey.How does head CT correlate with ICP monitoring and impact monitoring discontinuation in trauma patients with a Marshall CT score of I–II?Impact of massive transfusion protocol and exclusion of plasma products from female donors on outcome of trauma patients in Calgary region of Alberta Health Services.Primary impact arthrodesis for a neglected open Weber B ankle fracture dislocation.Impact of depression on neuropsychological functioning in electrical injury patients.Predicting the need for tracheostomy in patients with cervical spinal cord injury.Predicting crumping during computed tomography imaging using base deficit.Feasibility of using telehomecare technology to support patients with an acquired brain injury and family care-givers.Program changes impact the outcomes of severely injured patients.Do trauma performance indicators accurately reflect changes in a maturing trauma program?One-stop falls prevention information for clinicians: a multidisciplinary interactive algorithm for the prevention of falls in older adults.Use of focused assessment with sonography for trauma (FAST) for combat casualties in forward facilities.Alberta All-terrain Vehicle Working Group: a call to action.Observations and potential role for the rural trauma team development course (RTTDC) in India.An electronic strategy to facilitate information-sharing among trauma team leaders.Development of quality indicators of trauma care by a consensus panel.An evaluation of a proactive geriatric trauma consultation service.Celebrity injury-related deaths: Is a gangster rapper really gangsta?Prevention of delirium in trauma patients: Are we giving thiamine prophylaxis a fair chance?Intra-abdominal injury in patients who sustain more than one gunshot wound to the abdomen: Should non-operative management be used?Retrospective review of blunt thoracic aortic injury management according to current treatment recommendations.Telemedicine for trauma resuscitation: developing a regional system to improve access to expert trauma care in Ontario.Comparing trauma quality indicator data between a pediatric and an adult trauma hospital.Using local injury data to influence injury prevention priorities.Systems saving lives: a structured review of pediatric trauma systems.What do students think of the St. Michael’s Hospital ThinkFirst Injury Prevention Strategy for Youth?An evidence-based method for targeting a shaken baby syndrome prevention media campaign.The virtual mentor: cost-effective, nurse-practitioner performed, telementored lung sonography with remote physician guidance.Quality indicators used by teaching versus nonteaching international trauma centres.Compliance to advanced trauma life support protocols in adult trauma patients in the acute setting.Closing the quality improvement loop: a collaborative approach.National Trauma Registry: “collecting” it all in New Brunswick.Does delay to initial reduction attempt affect success rates for anterior shoulder dislocation (pilot study)?Use of multidisciplinary, multi-site morbidity and mortality rounds in a provincial trauma system.Caring about trauma care: public awareness, knowledge and perceptions.Assessing the quality of admission dictation at a level 1 trauma centre.Trauma trends in older adults: a decade in review.Blunt splenic injury in patients with hereditary spherocytosis: a population-based analysis.Analysis of trauma team activation in severe head injury: an institutional experience.ROTEM results correlate with fresh frozen plasma transfusion in trauma patients.10-year trend of assault in Alberta.10-year trend in alcohol use in major trauma in Alberta.10-year trend in major trauma injury related to motorcycles compared with all-terrain vehicles in Alberta.Referral to a community program for youth injured by violence: a feasibility study.New impaired driving laws impact on the trauma population at level 1 and 3 trauma centres in British Columbia, Canada.A validation study of the mobile medical unit/polyclinic team training for the Vancouver 2010 Winter Games.Inferior vena cava filter use in major trauma: the Sunny-brook experience, 2000–2011.Relevance of cellular microparticles in trauma-induced coagulopathy: a systemic review.Improving quality through trauma centre collaboratives.Predictors of acute stress response in adult polytrauma patients following injury.Patterns of outdoor recreational injury in northern British Columbia.Risk factors for loss-to-follow up among trauma patients include functional, socio-economic, and geographic determinants: Would mandating opt-out consent strategies minimize these risks?Med-evacs and mortality rates for trauma from Inukjuak, Nunavik, Quebec.Review of open abdomens in McGill University Health Centre.Are surgical interventions for trauma associated with the development of posttraumatic retained hemothorax and empyema?A major step in understanding the mechanisms of traumatic coagulopathy: the possible role of thrombin activatable fibrinolysis inhibitor.Access to trauma centre care for patients with major trauma.Repeat head computed tomography in anticoagulated traumatic brain injury patients: still warranted.Improving trauma system governance. Can J Surg 2012. [DOI: 10.1503/cjs.006312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
|
32
|
Immune and inflammatory mechanisms. Clin Kidney J 2011. [DOI: 10.1093/ndtplus/4.s2.53] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
|
33
|
Measurement of the positive muon lifetime and determination of the Fermi constant to part-per-million precision. PHYSICAL REVIEW LETTERS 2011; 106:041803. [PMID: 21405320 DOI: 10.1103/physrevlett.106.041803] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2010] [Indexed: 05/30/2023]
Abstract
We report a measurement of the positive muon lifetime to a precision of 1.0 ppm; it is the most precise particle lifetime ever measured. The experiment used a time-structured, low-energy muon beam and a segmented plastic scintillator array to record more than 2×10(12) decays. Two different stopping target configurations were employed in independent data-taking periods. The combined results give τ(μ(+)) (MuLan)=2 196 980.3(2.2) ps, more than 15 times as precise as any previous experiment. The muon lifetime gives the most precise value for the Fermi constant: G(F) (MuLan)=1.166 378 8(7)×10(-5) GeV(-2) (0.6 ppm). It is also used to extract the μ(-)p singlet capture rate, which determines the proton's weak induced pseudoscalar coupling g(P).
Collapse
|
34
|
Genetic analysis of clinical mastitis and somatic cell count traits in Austrian Fleckvieh cows. J Dairy Sci 2010; 93:5987-95. [DOI: 10.3168/jds.2010-3451] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2010] [Accepted: 08/12/2010] [Indexed: 11/19/2022]
|
35
|
Celecoxib treatment restores pharmacosensitivity in a rat model of pharmacoresistant epilepsy. Br J Pharmacol 2010; 160:1062-71. [PMID: 20590600 DOI: 10.1111/j.1476-5381.2010.00765.x] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
BACKGROUND AND PURPOSE A functional link between seizure-induced P-glycoprotein overexpression at the blood-brain barrier and therapeutic failure has been suggested by several studies using rodent epilepsy models and human epileptic tissue. Recently, we reported that interference with the mechanisms that up-regulate P-glycoprotein in response to seizure activity might provide a novel approach to control its expression in the epileptic brain. Based on these data, we hypothesized that blocking the appropriate signalling cascade by cyclooxygenase-2 inhibition should improve brain penetration of antiepileptic drugs and help to overcome drug resistance. EXPERIMENTAL APPROACH Effects of the selective cyclooxygenase-2 inhibitor celecoxib on the response to the P-glycoprotein substrate, phenobarbital, was evaluated in a chronic model of drug-resistant temporal lobe epilepsy in rats. Drug-resistant rats selected from this model exhibit a marked overexpression of P-glycoprotein in the hippocampus and other limbic brain regions. KEY RESULTS Responders and non-responders were selected from a group of rats with spontaneous recurrent seizures after prolonged treatment with phenobarbital at maximum tolerated doses. The efficacy of phenobarbital was re-evaluated following a 6 day treatment with celecoxib and the frequency of spontaneous recurrent seizures was significantly reduced in both groups of rats, phenobarbital responders or non-responders selected from the previous drug trial. CONCLUSIONS AND IMPLICATIONS Pretreatment with the cyclooxygenase-2 inhibitor restored the anticonvulsant activity of phenobarbital in rats that failed to exhibit a relevant response before celecoxib treatment. Our data provide further support for a novel therapeutic approach to overcome transporter-mediated drug resistance in epilepsies.
Collapse
|
36
|
A consensus genetic map of chickpea (Cicer arietinum L.) based on 10 mapping populations. EUPHYTICA 2010. [PMID: 0 DOI: 10.1007/s10681-010-0157-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
|
37
|
Mastitis hervorgerufen durch Mycobacterium smegmatis bei einem Rind. Tierarztl Prax Ausg G Grosstiere Nutztiere 2010. [DOI: 10.1055/s-0038-1621620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
|
38
|
Desensitization of endothelial P2Y1 receptors by PKC-dependent mechanisms in pressurized rat small mesenteric arteries. Br J Pharmacol 2009; 158:1609-20. [PMID: 19845669 DOI: 10.1111/j.1476-5381.2009.00456.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND AND PURPOSE Extracellular nucleotides play a crucial role in the regulation of vascular tone and blood flow. Stimulation of endothelial cell P2Y1 receptors evokes concentration-dependent full dilatation of resistance arteries. However, this GPCR can desensitize upon prolonged exposure to the agonist. Our aim was to determine the extent and nature of P2Y1 desensitization in isolated and pressurized rat small mesenteric arteries. EXPERIMENTAL APPROACH The non-hydrolyzable selective P2Y1 agonist ADPbetaS (3 microM) was perfused through the lumen of arteries pressurized to 70 mmHg. Changes in arterial diameter and endothelial cell [Ca(2+)](i) were obtained in the presence and absence of inhibitors of protein kinase C (PKC). KEY RESULTS ADPbetaS evoked rapid dilatation to the maximum arterial diameter but faded over time to a much-reduced plateau closer to 35% dilatation. This appeared to be due to desensitization of the P2Y1 receptor, as subsequent endothelium-dependent dilatation to acetylcholine (1 microM) remained unaffected. Luminal treatment with the PKC inhibitors BIS-I (1 microM) or BIS-VIII (1 microM) tended to augment concentration-dependent dilatation to ADPbetaS (0.1-3 microM) and prevented desensitization. Another PKC inhibitor, Gö 6976 (1 microM), was less effective in preventing desensitization. Measurements of endothelial cell [Ca(2+)](i) in pressurized arteries confirmed the P2Y1 receptor but not M(3) muscarinic receptor desensitization. CONCLUSIONS AND IMPLICATIONS These data demonstrate for the first time the involvement of PKC in the desensitization of endothelial P2Y1 receptors in pressurized rat mesenteric arteries, which may have important implications in the control of blood flow by circulating nucleotides.
Collapse
|
39
|
Effects of feed particle size at dietary presence of added organic acids on caecal parameters and the prevalence ofSalmonellain fattening pigs on farm and at slaughter. J Anim Physiol Anim Nutr (Berl) 2009; 93:423-30. [DOI: 10.1111/j.1439-0396.2008.00821.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
40
|
Haemodynamic changes and stress responses of piglets to surgery during total intravenous anaesthesia with propofol and fentanyl. Lab Anim 2009; 43:243-8. [DOI: 10.1258/la.2008.0080026] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The purpose of the study was to assess the haemodynamic (blood pressure and heart rate) changes and stress responses (serum cortisol and serum amyloid A [SAA] concentrations) to surgery in piglets during total intravenous anaesthesia (TIVA) with propofol and fentanyl. After preanaesthetic medication with intramuscular midazolam (0.5 mg/kg body mass), ketamine (10 mg/kg) and butorphanol (0.5 mg/kg) anaesthesia was induced in five piglets, with intravenous propofol (1 mg/kg) followed by tracheal intubation and mechanical lung ventilation. Soft tissue surgery was performed in the jugular and inguinal regions during TIVA with propofol (8 mg/kg/h) and fentanyl (35 μg/kg/h). Anaesthesia was maintained for 300 min after surgery as the piglets were the control group of a project involving extracorporeal membrane oxygenation. Mean plasma cortisol concentration decreased significantly ( P < 0.05) from 59 ± 39.9 nmol/L (mean ± 1 SD) before surgery to 7.5 ± 2.5 nmol/L 300 min after end of surgical procedure. The mean SAA concentrations increased over the same period from 1.6 ± 2.3 μg/mL to 4.2 ± 5.6 μg/mL without statistical significance. The baseline (presurgery) mean arterial pressure (MAP) was 72 ± 9 mmHg compared with 72 ± 11 mmHg 300 min after end of surgery. Neither heart rate nor lactate concentrations changed significantly over the same time points: heart rate was 104 ± 11 and 103 ± 15 beats/min whereas mean lactate concentrations were reduced from 1.14 ± 0.45 mmol/L to 0.90 ± 0.22 mmol/L. Haemodynamic stability, a decrease in serum cortisol and a non-statistically significant rise in mean SAA concentrations suggest that the anaesthetic described suppresses the stress response of piglets to surgery without adverse cardiovascular effects. Therefore, it may prove useful in cardiovascular research.
Collapse
|
41
|
Detection of estrogenically active substances in diets for sows by an in vitro bioassay supported by HPLC analysis. J Anim Physiol Anim Nutr (Berl) 2008; 92:337-44. [DOI: 10.1111/j.1439-0396.2007.00797.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
42
|
|
43
|
Hirnmetastasen beim Hodentumor. Aktuelle Urol 2008. [DOI: 10.1055/s-2008-1061378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
44
|
Das Skrotälhamatom als seltene Komplikation nach angiographischen und angioplastischen Eingriffen. Aktuelle Urol 2008. [DOI: 10.1055/s-2008-1061206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
45
|
Metastase eines Prostatakarzinoms im Hoden. Aktuelle Urol 2008. [DOI: 10.1055/s-2008-1060599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
46
|
Palliation von Knochenmetastasen mit Rhenium (Re-186 HEDP). Aktuelle Urol 2008. [DOI: 10.1055/s-2008-1054298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
47
|
Is 3D MR molecular imaging of neovasculature prognostic of tumor response to antiangiogenic therapy? FASEB J 2008. [DOI: 10.1096/fasebj.22.1_supplement.898.40] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
48
|
Measurement of Upsilon production for p + p and p + d interactions at 800 GeV/c. PHYSICAL REVIEW LETTERS 2008; 100:062301. [PMID: 18352463 DOI: 10.1103/physrevlett.100.062301] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2007] [Indexed: 05/26/2023]
Abstract
We report a high statistics measurement of Upsilon production with an 800 GeV/c proton beam on hydrogen and deuterium targets. The dominance of the gluon-gluon fusion process for Upsilon production at this energy implies that the cross section ratio, sigma(p+d-->Upsilon)/2sigma(p+p-->Upsilon), is sensitive to the gluon content in the neutron relative to that in the proton. Over the kinematic region 0<x(F)<0.6, this ratio is found to be consistent with unity, in striking contrast to the behavior of the Drell-Yan cross section ratio sigma(p+d)(DY)/2sigma(p+p)(DY). This result shows that the gluon distributions in the proton and neutron are very similar. The Upsilon production cross sections are also compared with the p+d and p+Cu cross sections from earlier measurements.
Collapse
|
49
|
Abstract
INTRODUCTION Cognitive complaints, such as poor concentration and memory deficits, are frequent after whiplash injury and play an important role in disability. The origin of these complaints is discussed controversially. Some authors postulate brain lesions as a consequence of whiplash injuries. Potential diffuse axonal injury (DAI) with subsequent atrophy of the brain and ventricular expansion is of particular interest as focal brain lesions have not been documented so far in whiplash injury. OBJECTIVE To investigate whether traumatic brain injury can be identified using a magnetic resonance (MR)-based quantitative analysis of normalized ventricle-brain ratios (VBR) in chronic whiplash patients with subjective cognitive impairment that cannot be objectively confirmed by neuropsychological testing. MATERIALS AND METHODS MR examination was performed in 21 patients with whiplash injury and symptom persistence for 9 months on average and in 18 matched healthy controls. Conventional MR imaging (MRI) was used to assess the volumes of grey and white matter and of ventricles. The normalized VBR was calculated. RESULTS The values of normalized VBR did not differ in whiplash patients when compared with that in healthy controls (F = 0.216, P = 0.645). CONCLUSIONS This study does not support loss of brain tissue following whiplash injury as measured by VBR. On this basis, traumatic brain injury with subsequent DAI does not seem to be the underlying mechanism for persistent concentration and memory deficits that are subjectively reported but not objectively verifiable as neuropsychological deficits.
Collapse
|
50
|
Improved measurement of the positive-muon lifetime and determination of the Fermi constant. PHYSICAL REVIEW LETTERS 2007; 99:032001. [PMID: 17678280 DOI: 10.1103/physrevlett.99.032001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2007] [Indexed: 05/16/2023]
Abstract
The mean life of the positive muon has been measured to a precision of 11 ppm using a low-energy, pulsed muon beam stopped in a ferromagnetic target, which was surrounded by a scintillator detector array. The result, tau(micro)=2.197 013(24) micros, is in excellent agreement with the previous world average. The new world average tau(micro)=2.197 019(21) micros determines the Fermi constant G(F)=1.166 371(6)x10(-5) GeV-2 (5 ppm). Additionally, the precision measurement of the positive-muon lifetime is needed to determine the nucleon pseudoscalar coupling g(P).
Collapse
|