1,559 research outputs found
Viscoelastic behaviour of human mesenchymal stem cells
<p>Abstract</p> <p>Background</p> <p>In this study, we have investigated the viscoelastic behaviour of individual human adult bone marrow-derived mesenchymal stem cells (hMSCs) and the role of F-actin filaments in maintaining these properties, using micropipette aspiration technique together with a standard linear viscoelastic solid model.</p> <p>Results</p> <p>Under a room temperature of 20°C, the instantaneous and equilibrium Young's modulus, <it>E</it><sub>0 </sub>and <it>E</it><sub>∞</sub>, were found to be 886 ± 289 Pa and 372 ± 125 Pa, respectively, while the apparent viscosity, <it>μ</it>, was 2710 ± 1630 Pa·s. hMSCs treated with cytochalasin D up to 20 μM at 20°C registered significant drop of up to 84% in stiffness and increase of up to 255% in viscosity. At the physiological temperature of 37°C, <it>E</it><sub>0 </sub>and <it>E</it><sub>∞ </sub>have decreased by 42–66% whereas <it>μ </it>has increased by 95%, compared to the control. Majority of the hMSCs behave as viscoelastic solid with a rapid initial increase in aspiration length and it gradually levels out with time. Three other types of non-typical viscoelastic behavior of hMSCs were also seen.</p> <p>Conclusion</p> <p>hMSCs behave as viscoelastic solid. Its viscoelstic behaviour are dependent on the structural integrity of the F-actin filaments and temperature.</p
Investigation of therapeutic efficacy and mechanisms of polysaccharide of dendrobium officinale in alleviating cigarette-induced pulmonary inflammation
Posters: no. 13PS36Dendrobium officinale is a medicinal plant from the Orchidaceae family. It has been listed in the latest edition of the Chinese Pharmacopoeia as medicinal material Dendrobii Officinalis Caulis (Tiepishihu) because of its treatment efficacy. According to the Pharmacopoeia it benefits the stomach, promotes the production of body fluid, nourishes yin and eliminates evil-heat. Consequently it com...published_or_final_versio
Lack of Cardiac Nerve Sprouting after Intramyocardial Transplantation of Bone Marrow-Derived Stem Cells in a Swine Model of Chronic Ischemic Myocardium
Previous experimental studies suggested that mesenchymal stem cell transplantation causes cardiac nerve sprouting; however, whether bone marrow (BM)-derived mononuclear cells (MNC) and endothelial progenitor cells (EPC) can also lead to cardiac nerve sprouting and alter gap junction expression remains unclear. We investigated the effect of electroanatomical mapping-guided direct intramyocardial transplantation of BM-MNC (n = 8) and CD31+EPC (n = 8) compared with saline control (n = 8) on cardiac nerve sprouting and gap junction expression in a swine model of chronic ischemic myocardium. At 12 weeks after transplantation, the distribution and density of cardiac nerve sprouting were determined by staining of tyrosine hydroxylase (TH) and growth associated protein 43(GAP-43) and expression of connexin 43 in the targeted ischemic and remote normal myocardium. After 12 weeks, no animal developed sudden death after the transplantation. There were no significant differences in the number of cells with positive staining of TH and GAP-43 in the ischemic and normal myocardium between three groups. Furthermore, expression of connexin 43 was also similar in the ischemic and normal myocardia in each group of animals (P > 0.05). The results of this study demonstrated that intramyocardial BM-derived MNC or EPC transplantation in a large animal model of chronic myocardial ischemia was not associated with increased cardiac nerve sprouting over the ischemic myocardium
Successful Treatment of Novel H1N1 Influenza related Fulminant Myocarditis with Extracorporeal Life Support
The prevalence of myocardial involvement in influenza infection ranges from 0% to 12%. The 2009 pH1N1 influenza virus, formerly known as swine flu, first appeared in Mexico and the United States of America in March and April 2009 and has swept the globe with unprecedented speed. We report a case of fulminant myocarditis associated with this virus treated successfully using extra-corporal membrane oxygenator
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Projected WIMP sensitivity of the LUX-ZEPLIN dark matter experiment
LUX-ZEPLIN (LZ) is a next-generation dark matter direct detection experiment that will operate 4850 feet underground at the Sanford Underground Research Facility (SURF) in Lead, South Dakota, USA. Using a two-phase xenon detector with an active mass of 7 tonnes, LZ will search primarily for low-energy interactions with weakly interacting massive particles (WIMPs), which are hypothesized to make up the dark matter in our galactic halo. In this paper, the projected WIMP sensitivity of LZ is presented based on the latest background estimates and simulations of the detector. For a 1000 live day run using a 5.6-tonne fiducial mass, LZ is projected to exclude at 90% confidence level spin-independent WIMP-nucleon cross sections above 1.4×10-48 cm2 for a 40 GeV/c2 mass WIMP. Additionally, a 5σ discovery potential is projected, reaching cross sections below the exclusion limits of recent experiments. For spin-dependent WIMP-neutron(-proton) scattering, a sensitivity of 2.3×10-43 cm2 (7.1×10-42 cm2) for a 40 GeV/c2 mass WIMP is expected. With underground installation well underway, LZ is on track for commissioning at SURF in 2020
Simulations of events for the LUX-ZEPLIN (LZ) dark matter experiment
The LUX-ZEPLIN dark matter search aims to achieve a sensitivity to the WIMP-nucleon spin-independent cross-section down to (1–2)×10−12 pb at a WIMP mass of 40 GeV/c2. This paper describes the simulations framework that, along with radioactivity measurements, was used to support this projection, and also to provide mock data for validating reconstruction and analysis software. Of particular note are the event generators, which allow us to model the background radiation, and the detector response physics used in the production of raw signals, which can be converted into digitized waveforms similar to data from the operational detector. Inclusion of the detector response allows us to process simulated data using the same analysis routines as developed to process the experimental data
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Projected sensitivity of the LUX-ZEPLIN experiment to the 0νββ decay of Xe 136
The LUX-ZEPLIN (LZ) experiment will enable a neutrinoless double β decay search in parallel to the main science goal of discovering dark matter particle interactions. We report the expected LZ sensitivity to Xe136 neutrinoless double β decay, taking advantage of the significant (>600 kg) Xe136 mass contained within the active volume of LZ without isotopic enrichment. After 1000 live-days, the median exclusion sensitivity to the half-life of Xe136 is projected to be 1.06×1026 years (90% confidence level), similar to existing constraints. We also report the expected sensitivity of a possible subsequent dedicated exposure using 90% enrichment with Xe136 at 1.06×1027 years
MRI classification of interspinous ligament degeneration of the lumbar spine: intraobserver and interobserver reliability and the frequency of disagreement
Posterior spinal ligament pathology is becoming increasingly recognized as a significant cause of low back pain. Despite the growing clinical importance of interspinous ligament degeneration in low back pain patients, formal reliability studies for the magnetic resonance imaging (MRI) evaluation of interspinous ligaments have not been performed. We proposed an MRI classification system for interspinous ligament degeneration and conducted a comprehensive reliability and reproducibility assessment. Fifty patients who had low back pain with or without leg discomfort (26 males and 24 females) with a mean age of 48.8 years (range 23–85 years) were studied. The classification for lumbar interspinous ligament degeneration was developed on the basis of the literature using mid-sagittal T1- and T2-weighted images. Three spine surgeons independently graded a total of 200 interspinous ligament levels. Intraobserver and interobserver reliability were assessed by kappa statistics. The frequency of disagreement was also identified. The intraobserver agreement was excellent in all readers (kappa range 0.840–0.901). The interobserver agreement was lower as expected, and was substantial to excellent (kappa range 0.726–0.818). Overall complete agreement was obtained in 87.8% of all interspinous ligament levels. A difference of 1, 2, and 3 grades occurred in 8.1, 3.0, and 1.1% of readings, respectively. This proposed MRI classification of interspinous ligament degeneration was simple, reliable, and reproducible. Its use as a standardized nomenclature in clinical and radiographic research may be recommended
Sensitivity, specificity, and reproducibility of RNA-Seq differential expression calls
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