Effects of Perchlorate on Organic Molecules under Simulated Mars Conditions

NASA Astrophysics Data System (ADS)

Carrier, B. L.; Kounaves, S. P.

2014-12-01

Perchlorate (ClO4-) was discovered in the northern polar region of Mars by the Mars Phoenix Lander in 2008 and has also been recently detected by the Curiosity Rover in Gale Crater [1,2]. Perchlorate has also been shown to be formed under current Mars conditions via the oxidation of mineral chlorides, further supporting the theory that perchlorate is present globally on Mars [3]. The discovery of perchlorate on Mars has raised important questions about the effects of perchlorate on the survival and detection of organic molecules. Although it has been shown that pyrolysis in the presence of perchlorate results in the alteration or destruction of organic molecules [4], few studies have been conducted on the potential effects of perchlorate on organic molecules under martian surface conditions. Although perchlorate is typically inert under Mars-typical temperatures [5], perchlorate does absorb high energy UV radiation, and has been shown to decompose to form reactive oxychlorine species such as chlorite (ClO2-) when exposed to martian conditions including UV or ionizing radiation [6,7]. Here we investigate the effects of perchlorate on the organic molecules tryptophan, benzoic acid and mellitic acid in order to determine how perchlorate may alter these compounds under Mars conditions. Experiments are performed in a Mars Simulation Chamber (MSC) capable of reproducing the temperature, pressure, atmospheric composition and UV flux found on Mars. Soil simulants are prepared consisting of SiO2 and each organic, as well as varying concentrations of perchlorate salts, and exposed in the MSC. Subsequent to exposure in the MSC samples are leached and the leachate analyzed by HPLC and LC-MS to determine the degree of degradation of the original organic and the identity of any potential decomposition products formed by oxidation or chlorination. References: [1] Kounaves et al., J. Geophys. Res. Planets, Vol. 115, p. E00E10, 2010 [2] Glavin et al., J. Geophys. Res. Planets, Vol. 118, p. 1955, 2013 [3] Carrier & Kounaves (2014), Abstract #2570, 45th Lunar and Planetary Science Conference, [4] Kerr, Science, Vol. 340, p. 138, 2013 [5] Catling et al., J. Geophys. Res., Vol. 115, p. E00E11, 2010 [6] Martucci (2012), National Conference of Undergraduate Research [7] Quinn et al, Astrobiology, Vol. 13(6) p. 515-20, 2013

Stochastic Simulation Tool for Aerospace Structural Analysis

NASA Technical Reports Server (NTRS)

Knight, Norman F.; Moore, David F.

2006-01-01

Stochastic simulation refers to incorporating the effects of design tolerances and uncertainties into the design analysis model and then determining their influence on the design. A high-level evaluation of one such stochastic simulation tool, the MSC.Robust Design tool by MSC.Software Corporation, has been conducted. This stochastic simulation tool provides structural analysts with a tool to interrogate their structural design based on their mathematical description of the design problem using finite element analysis methods. This tool leverages the analyst's prior investment in finite element model development of a particular design. The original finite element model is treated as the baseline structural analysis model for the stochastic simulations that are to be performed. A Monte Carlo approach is used by MSC.Robust Design to determine the effects of scatter in design input variables on response output parameters. The tool was not designed to provide a probabilistic assessment, but to assist engineers in understanding cause and effect. It is driven by a graphical-user interface and retains the engineer-in-the-loop strategy for design evaluation and improvement. The application problem for the evaluation is chosen to be a two-dimensional shell finite element model of a Space Shuttle wing leading-edge panel under re-entry aerodynamic loading. MSC.Robust Design adds value to the analysis effort by rapidly being able to identify design input variables whose variability causes the most influence in response output parameters.

Vaccination efficacy with marrow mesenchymal stem cell against cancer was enhanced under simulated microgravity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Jing; Chen, Jun; Li, Xiuyu

Stem cell vaccination can induce consistent and strong anti-tumor immunity against cancer in mice model. The antigenic similarity between tumors and embryos has been appreciated for many years and reflects the expression of embryonic gene products by cancer cells and/or cancer-initiating stem cells. Taking advantage of this similarity, we have tested a prophylactic lung cancer vaccine composed of allogeneic murine MSCs. Based on this conception, we first compared their tumor vaccines intervention effects of adult MSCs and MSCs under simulated microgravity (MSC/SMG). In this study, BALB/c mice were vaccinated with MSCs or MSC/SMG, compared with mice vaccinated with phosphate bufferedmore » saline (PBS) as negative controls. We then subcutaneously implanted the A549 human lung cancer cell line into vaccinated mice and monitored tumor growth potential in vivo. The smaller tumor size and less tumor weight were observed in mice vaccinated with MSCs or MSC/SMG, compared with that of the Control group. Particularly, it was much more significant in the group of MSC/SMG than that group of the MSCs. Vaccination with SMG treated MSCs inhibited proliferation and promoted apoptosis of tumor tissue. SMG/MSC vaccination induced bothTh1-mediated cytokine response; CD8-dependent cytotoxic response which reduced the proportion of Treg cells. Furthermore, SMG/MSC vaccination significantly increased MHC1 and HSPs proteins expression. In conclusion, we demonstrated the SMG could improve tumor-suppressive activity of MSC. The enhanced anti-tumor immune response of MSCs/SMG was strongly associated with the higher expression of MHC class I molecule on DCs, and the abundance of HSPs in the SMG treated MSCs may make antigens in the MSC more cross-presentable to the host DCs for generating protective antitumor activity. This study gains an insight into the mechanism of MSCs anti-tumor efficacy and gives a new strategy for cancer therapies in the future. - Highlights: • Vaccination with SMG treated MSCs inhibited tumor growth. • SMG/MSC vaccination induced Th1-mediated cytokine response, elicited CD8-dependent cytotoxic response and reduced the proportion of Treg cells. • SMG/MSC vaccination increased MHC1 and HSPs proteins expression.« less

Rainfall simulation in education

NASA Astrophysics Data System (ADS)

Peters, Piet; Baartman, Jantiene; Gooren, Harm; Keesstra, Saskia

2016-04-01

Rainfall simulation has become an important method for the assessment of soil erosion and soil hydrological processes. For students, rainfall simulation offers an year-round, attractive and active way of experiencing water erosion, while not being dependent on (outdoors) weather conditions. Moreover, using rainfall simulation devices, they can play around with different conditions, including rainfall duration, intensity, soil type, soil cover, soil and water conservation measures, etc. and evaluate their effect on erosion and sediment transport. Rainfall simulators differ in design and scale. At Wageningen University, both BSc and MSc student of the curriculum 'International Land and Water Management' work with different types of rainfall simulation devices in three courses: - A mini rainfall simulator (0.0625m2) is used in the BSc level course 'Introduction to Land Degradation and Remediation'. Groups of students take the mini rainfall simulator with them to a nearby field location and test it for different soil types, varying from clay to more sandy, slope angles and vegetation or litter cover. The groups decide among themselves which factors they want to test and they compare their results and discuss advantage and disadvantage of the mini-rainfall simulator. - A medium sized rainfall simulator (0.238 m2) is used in the MSc level course 'Sustainable Land and Water Management', which is a field practical in Eastern Spain. In this course, a group of students has to develop their own research project and design their field measurement campaign using the transportable rainfall simulator. - Wageningen University has its own large rainfall simulation laboratory, in which a 15 m2 rainfall simulation facility is available for research. In the BSc level course 'Land and Water Engineering' Student groups will build slopes in the rainfall simulator in specially prepared containers. Aim is to experience the behaviour of different soil types or slope angles when (heavy) rain occurs. The MSc level course 'Fundamentals of Land Management' students carry out a hands-on practical in which they compare soil type and design and evaluate the effect of soil and water conservation measures. Also, MSc thesis research is being carried out using this facility. For instance, the distribution and movement of pesticide Glyphosate with sediment transportation was being quantified using the rainfall simulation facility.

NUMERICAL SIMULATION OF NANOINDENTATION AND PATCH CLAMP EXPERIMENTS ON MECHANOSENSITIVE CHANNELS OF LARGE CONDUCTANCE IN ESCHERICHIA COLI

PubMed Central

Tang, Yuye; Chen, Xi; Yoo, Jejoong; Yethiraj, Arun; Cui, Qiang

2010-01-01

A hierarchical simulation framework that integrates information from all-atom simulations into a finite element model at the continuum level is established to study the mechanical response of a mechanosensitive channel of large conductance (MscL) in bacteria Escherichia Coli (E.coli) embedded in a vesicle formed by the dipalmitoylphosphatidycholine (DPPC) lipid bilayer. Sufficient structural details of the protein are built into the continuum model, with key parameters and material properties derived from molecular mechanics simulations. The multi-scale framework is used to analyze the gating of MscL when the lipid vesicle is subjective to nanoindentation and patch clamp experiments, and the detailed structural transitions of the protein are obtained explicitly as a function of external load; it is currently impossible to derive such information based solely on all-atom simulations. The gating pathways of E.coli-MscL qualitatively agree with results from previous patch clamp experiments. The gating mechanisms under complex indentation-induced deformation are also predicted. This versatile hierarchical multi-scale framework may be further extended to study the mechanical behaviors of cells and biomolecules, as well as to guide and stimulate biomechanics experiments. PMID:21874098

Three Dimensional Architecture of Membrane-Embedded MscS in the Closed Conformation

PubMed Central

Vásquez, Valeria; Sotomayor, Marcos; Cortes, D. Marien; Roux, Benoît; Schulten, Klaus; Perozo, Eduardo

2009-01-01

The mechanosensitive channel of small conductance (MscS) is part of a coordinated response to osmotic challenges in E. coli. MscS opens as a result of membrane tension changes, thereby releasing small solutes and effectively acting as an osmotic safety valve. Both, the functional state depicted by its crystal structure and its gating mechanism remain unclear. Here, we combine site-directed spin labeling, electron paramagnetic resonance (EPR) spectroscopy, and molecular dynamics simulations with novel energy restraints based on experimental EPR data to investigate the native transmembrane and periplasmic molecular architecture of closed MscS in a lipid bilayer. In the closed conformation, MscS shows a more compact transmembrane domain than in the crystal structure, characterized by a realignment of the transmembrane segments towards the normal of the membrane. The previously unresolved NH2-terminus forms a short helical hairpin capping the extracellular ends of TM1 and TM2 and in close interaction with the bilayer interface. The present three-dimensional model of membrane-embedded MscS in the closed state represents a key step in determining the molecular mechanism of MscS gating. PMID:18343404

Design and efficacy of a single-use bioreactor for heart valve tissue engineering.

PubMed

Converse, Gabriel L; Buse, Eric E; Neill, Kari R; McFall, Christopher R; Lewis, Holley N; VeDepo, Mitchell C; Quinn, Rachael W; Hopkins, Richard A

2017-02-01

Heart valve tissue engineering offers the promise of improved treatments for congenital heart disorders; however, widespread clinical availability of a tissue engineered heart valve (TEHV) has been hindered by scientific and regulatory concerns, including the lack of a disposable, bioreactor system for nondestructive valve seeding and mechanical conditioning. Here we report the design for manufacture and the production of full scale, functional prototypes of such a system. To evaluate the efficacy of this bioreactor as a tool for seeding, ovine aortic valves were decellularized and subjected to seeding with human mesenchymal stem cells (hMSC). The effects of pulsatile conditioning using cyclic waveforms tuned to various negative and positive chamber pressures were evaluated, with respect to the seeding of cells on the decellularized leaflet and the infiltration of seeded cells into the interstitium of the leaflet. Infiltration of hMSCs into the aortic valve leaflet was observed following 72 h of conditioning under negative chamber pressure. Additional conditioning under positive pressure improved cellular infiltration, while retaining gene expression within the MSC-valve interstitial cell phenotype lineage. This protocol resulted in a subsurface pilot population of cells, not full tissue recellularization. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 249-259, 2017. © 2015 Wiley Periodicals, Inc.

Influence of long-term gravity vector changes on mesenchymal stem cells in vitro

NASA Astrophysics Data System (ADS)

Buravkova, L. B.; Merzlikina, N. V.; Romanov, Yu. A.; Buravkov, S. V.

2005-08-01

In vivo and in vitro studies have identified the bone marrow as the primary source of a multipotential mesenchymal stem cells (MSC) that give rise to progenitors for several mesenchymal tissues, including bone, cartilage, tendon, adipose, muscle and hematopoietic-supporting stroma. It is known that MSC are sensitive to chemical signals and mechanical stimuli. It was also suggested that microgravity may influence on progenitor cells and induce abnormalities in cellular differentiation in muscle and skeletal components leading to the changes in physiological regeneration of these tissues. To prove gravitational sensitivity of MSC, we studied the effects of prolonged clinorotation on cultured human MSC (hMSC) morphology, actin cytoskeleton organization and phenotype. It was found that the proliferation rate was significantly decreased during clinorotation but augmented during recovery. The cell cytoskeleton displayed actin filament thinning and altered morphology at clinorotation. The production of interleukin-6 was increased and expression of surface molecules was modified by simulated microgravity. Observed changes of cultured hMSC behavior suggest the gravitational sensitivity of human stromal progenitor cells.

Evaluation of chemical simulations from EMEP4ASIA

NASA Astrophysics Data System (ADS)

Pommier, M.; Gauss, M.; Fagerli, H.; Benedictow, A.; Nyiri, A.; Valdebenito, Á.; Wind, P.

2016-12-01

The EMEP/MSC-W chemistry transport model (CTM) has been used for decades to simulate concentrations of surface air pollutants over Europe and to calculate source-receptor relationships between European countries. Within the framework of the operational air pollution forecasts for East Asia, being offered by the EU project PANDA, this study aims to evaluate the EMEP/MSC-W CTM in simulating high pollution events over Asian cities. This work is the first attempt to use this CTM with a fine horizontal resolution (0.1°×0.1°) over Asia and to simulate the pollution over urban regions. The main part of the work has been to focus on the evaluation of the EMEP/MSC-W CTM with measurements from different platforms (satellite, ground-based, in situ) and to identify the biases or the errors in the simulation. This evaluation is important in order to establish the capabilities of the model to identify air pollution sources. Regional distributions and temporal variation of main pollutants are thus discussed. For example, the daily variation in Ox is well captured while the NOx is under-predicted and the O3 is overestimated, especially in winter. The CTM performs also very well on day-to-day variation in PM25 or on the regional distribution in CO total column as over Beijing.

Impact Testing and Simulation of a Crashworthy Composite Fuselage Section with Energy-Absorbing Seats and Dummies

NASA Technical Reports Server (NTRS)

Fasanella, Edwin L.; Jackson, Karen E.

2002-01-01

A 25-ft/s vertical drop test of a composite fuselage section was conducted with two energy-absorbing seats occupied by anthropomorphic dummies to evaluate the crashworthy features of the fuselage section and to determine its interaction with the seats and dummies. The 5-ft. diameter fuselage section consists of a stiff structural floor and an energy-absorbing subfloor constructed of Rohacel foam blocks. The experimental data from this test were analyzed and correlated with predictions from a crash simulation developed using the nonlinear, explicit transient dynamic computer code, MSC.Dytran. The anthropomorphic dummies were simulated using the Articulated Total Body (ATB) code, which is integrated into MSC.Dytran.

Impact Testing and Simulation of a Crashworthy Composite Fuselage Section with Energy-Absorbing Seats and Dummies

NASA Technical Reports Server (NTRS)

Fasanella, Edwin L.; Jackson, Karen E.

2002-01-01

A 25-ft/s vertical drop test of a composite fuselage section was conducted with two energy-absorbing seats occupied by anthropomorphic dummies to evaluate the crashworthy features of the fuselage section and to determine its interaction with the seats and dummies. The 5-ft diameter fuselage section consists of a stiff structural floor and an energy-absorbing subfloor constructed of Rohacel foam blocks. The experimental data from this test were analyzed and correlated with predictions from a crash simulation developed using the nonlinear, explicit transient dynamic computer code, MSC.Dytran. The anthropomorphic dummies were simulated using the Articulated Total Body (ATB) code, which is integrated into MSC.Dytran.

A Finite Element Framework for Studying the Mechanical Response of Macromolecules: Application to the Gating of the Mechanosensitive Channel MscL

PubMed Central

Tang, Yuye; Cao, Guoxin; Chen, Xi; Yoo, Jejoong; Yethiraj, Arun; Cui, Qiang

2006-01-01

The gating pathways of mechanosensitive channels of large conductance (MscL) in two bacteria (Mycobacterium tuberculosis and Escherichia coli) are studied using the finite element method. The phenomenological model treats transmembrane helices as elastic rods and the lipid membrane as an elastic sheet of finite thickness; the model is inspired by the crystal structure of MscL. The interactions between various continuum components are derived from molecular-mechanics energy calculations using the CHARMM all-atom force field. Both bacterial MscLs open fully upon in-plane tension in the membrane and the variation of pore diameter with membrane tension is found to be essentially linear. The estimated gating tension is close to the experimental value. The structural variations along the gating pathway are consistent with previous analyses based on structural models with experimental constraints and biased atomistic molecular-dynamics simulations. Upon membrane bending, neither MscL opens substantially, although there is notable and nonmonotonic variation in the pore radius. This emphasizes that the gating behavior of MscL depends critically on the form of the mechanical perturbation and reinforces the idea that the crucial gating parameter is lateral tension in the membrane rather than the curvature of the membrane. Compared to popular all-atom-based techniques such as targeted or steered molecular-dynamics simulations, the finite element method-based continuum-mechanics framework offers a unique alternative to bridge detailed intermolecular interactions and biological processes occurring at large spatial scales and long timescales. It is envisioned that such a hierarchical multiscale framework will find great value in the study of a variety of biological processes involving complex mechanical deformations such as muscle contraction and mechanotransduction. PMID:16731564

Comparative effects of mesenchymal stem cell therapy in distinct stages of chronic renal failure.

PubMed

Caldas, Heloisa Cristina; de Paula Couto, Thaís Amarante Peres; Fernandes, Ida Maria Maximina; Baptista, Maria Alice Sperto Ferreira; Kawasaki-Oyama, Rosa Sayoko; Goloni-Bertollo, Eny Maria; Braile, Domingo Marcolino; Abbud-Filho, Mario

2015-10-01

The therapeutic potential of adult stem cells in the treatment of chronic diseases is becoming increasingly evident. In the present study, we sought to assess whether treatment with mesenchymal stem cells (MSCs) efficiently retards progression of chronic renal failure (CRF) when administered to experimental models of less severe CRF. We used two renal mass reduction models to simulate different stages of CRF (5/6 or 2/3 mass renal reduction). Renal functional parameters measured were serum creatinine (SCr), creatinine clearance (CCr), rate of decline in CCr (RCCr), and 24-h proteinuria (PT24h). We also evaluated renal morphology by histology and immunohistochemistry. MSCs were obtained from bone marrow aspirates and injected into the renal parenchyma of the remnant kidneys of both groups of rats with CRF (MSC5/6 or MSC2/3). Animals from groups MSC5/6 and CRF2/3 seemed to benefit from MSC therapy because they showed significantly reduction in SCr and PT24h, increase in CCr and slowed the RCCr after 90 days. Treatment reduced glomerulosclerosis but significant improvement did occur in the tubulointerstitial compartment with much less fibrosis and atrophy. MSC therapy reduced inflammation by decreasing macrophage accumulation proliferative activity (PCNA-positive cells) and fibrosis (α-SM-actin). Comparisons of renal functional and morphological parameters responses between the two groups showed that rats MSC2/3 were more responsive to MSC therapy than MSC5/6. This study showed that MSC therapy is efficient to retard CRF progression and might be more effective when administered during less severe stages of CRF.

Modeling and analysis of dynamic characteristics of carrier system of machining center in MSC.Adams

NASA Astrophysics Data System (ADS)

Grinek, A. V.; Rybina, A. V.; Boychuk, I. P.; Dantsevich, I. M.; Hurtasenko, A. V.

2018-03-01

The simulation model with the help of vibration analysis was developed in MSC.Adams/Vibration and experimental research of the dynamic characteristics of a five-axis machining center was carried out. The amplitude-frequency characteristics, resonant frequencies in various directions are investigated. Dynamic and static rigidity, damping intensity and the coefficient of dynamism of the center are determined.

Simulation of an Impact Test of the All-Composite Lear Fan Aircraft

NASA Technical Reports Server (NTRS)

Stockwell, Alan E.; Jones, Lisa E. (Technical Monitor)

2002-01-01

An MSC.Dytran model of an all-composite Lear Fan aircraft fuselage was developed to simulate an impact test conducted at the NASA Langley Research Center Impact Dynamics Research Facility (IDRF). The test was the second of two Lear Fan impact tests. The purpose of the second test was to evaluate the performance of retrofitted composite energy-absorbing floor beams. A computerized photogrammetric survey was performed to provide airframe geometric coordinates, and over 5000 points were processed and imported into MSC.Patran via an IGES file. MSC.Patran was then used to develop the curves and surfaces and to mesh the finite element model. A model of the energy-absorbing floor beams was developed separately and then integrated into the Lear Fan model. Structural responses of components such as the wings were compared with experimental data or previously published analytical data wherever possible. Comparisons with experimental results were used to guide structural model modifications to improve the simulation performance. This process was based largely on qualitative (video and still camera images and post-test inspections) rather than quantitative results due to the relatively few accelerometers attached to the structure.

Water Dynamics and Dewetting Transitions in the Small Mechanosensitive Channel MscS

PubMed Central

Anishkin, Andriy; Sukharev, Sergei

2004-01-01

The dynamics of confined water in capillaries and nanotubes suggests that gating of ion channels may involve not only changes of the pore geometry, but also transitions between water-filled and empty states in certain locations. The recently solved heptameric structure of the small mechanosensitive channel of Escherichia coli, MscS, has revealed a relatively wide (7–15 Å) yet highly hydrophobic transmembrane pore. Continuum estimations based on the properties of pore surface suggest low conductance and a thermodynamic possibility of dewetting. To test the predictions we performed molecular dynamics simulations of MscS filled with flexible TIP3P water. Irrespective to the initial conditions, several independent 6-ns simulations converged to the same stable state with the pore water-filled in the wider part, but predominantly empty in the narrow hydrophobic part, displaying intermittent vapor-liquid transitions. The polar gain-of-function substitution L109S in the constriction resulted in a stable hydration of the entire pore. Steered passages of Cl− ions through the narrow part of the pore consistently produced partial ion dehydration and required a force of 200–400 pN to overcome an estimated barrier of 10–20 kcal/mole, implying negligibly low conductance. We conclude that the crystal structure of MscS does not represent an open state. We infer that MscS gate, which is similar to that of the nicotinic ACh receptor, involves a vapor-lock mechanism where limited changes of geometry or surface polarity can locally switch the regime between water-filled (conducting) and empty (nonconducting) states. PMID:15111405

Astronaut Alan Bean participates in lunar surface simulation

NASA Image and Video Library

1969-10-29

S69-56059 (24 Oct. 1969) --- Astronaut Alan L. Bean, lunar module pilot of the Apollo 12 lunar landing mission, participates in lunar surface simulation training in Building 29 at the Manned Spacecraft Center (MSC). Bean is strapped to a one-sixth gravity simulator.

Apollo 13 Astronaut Fred Haise during lunar surface simulation training

NASA Image and Video Library

1970-01-19

S70-24012 (19 Jan. 1970) --- Astronaut Fred W. Haise Jr., lunar module pilot of the Apollo 13 lunar landing mission, participates in lunar surface simulation training at the Manned Spacecraft Center (MSC). Haise is attached to a Six Degrees of Freedom Simulator.

Probabilistic structural analysis using a general purpose finite element program

NASA Astrophysics Data System (ADS)

Riha, D. S.; Millwater, H. R.; Thacker, B. H.

1992-07-01

This paper presents an accurate and efficient method to predict the probabilistic response for structural response quantities, such as stress, displacement, natural frequencies, and buckling loads, by combining the capabilities of MSC/NASTRAN, including design sensitivity analysis and fast probability integration. Two probabilistic structural analysis examples have been performed and verified by comparison with Monte Carlo simulation of the analytical solution. The first example consists of a cantilevered plate with several point loads. The second example is a probabilistic buckling analysis of a simply supported composite plate under in-plane loading. The coupling of MSC/NASTRAN and fast probability integration is shown to be orders of magnitude more efficient than Monte Carlo simulation with excellent accuracy.

Mental skills training effectively minimizes operative performance deterioration under stressful conditions: Results of a randomized controlled study.

PubMed

Anton, N E; Beane, J; Yurco, A M; Howley, L D; Bean, E; Myers, E M; Stefanidis, D

2018-02-01

Stress can negatively impact surgical performance, but mental skills may help. We hypothesized that a comprehensive mental skills curriculum (MSC) would minimize resident performance deterioration under stress. Twenty-four residents were stratified then randomized to receive mental skills and FLS training (MSC group), or only FLS training (control group). Laparoscopic suturing skill was assessed on a live porcine model with and without external stressors. Outcomes were compared with t-tests. Twenty-three residents completed the study. The groups were similar at baseline. There were no differences in suturing at posttest or transfer test under normal conditions. Both groups experienced significantly decreased performance when stress was applied, but the MSC group significantly outperformed controls under stress. This MSC enabled residents to perform significantly better than controls in the simulated OR under unexpected stressful conditions. These findings support the use of psychological skills as an integral part of a surgical resident training. Copyright © 2017 Elsevier Inc. All rights reserved.

Ang II-AT2R increases mesenchymal stem cell migration by signaling through the FAK and RhoA/Cdc42 pathways in vitro.

PubMed

Xu, Xiu-Ping; He, Hong-Li; Hu, Shu-Ling; Han, Ji-Bin; Huang, Li-Li; Xu, Jing-Yuan; Xie, Jian-Feng; Liu, Ai-Ran; Yang, Yi; Qiu, Hai-Bo

2017-07-12

Mesenchymal stem cells (MSCs) migrate via the bloodstream to sites of injury and are possibly attracted by inflammatory factors. As a proinflammatory mediator, angiotensin II (Ang II) reportedly enhances the migration of various cell types by signaling via the Ang II receptor in vitro. However, few studies have focused on the effects of Ang II on MSC migration and the underlying mechanisms. Human bone marrow MSCs migration was measured using wound healing and Boyden chamber migration assays after treatments with different concentrations of Ang II, an AT1R antagonist (Losartan), and/or an AT2R antagonist (PD-123319). To exclude the effect of proliferation on MSC migration, we measured MSC proliferation after stimulation with the same concentration of Ang II. Additionally, we employed the focal adhesion kinase (FAK) inhibitor PF-573228, RhoA inhibitor C3 transferase, Rac1 inhibitor NSC23766, or Cdc42 inhibitor ML141 to investigate the role of cell adhesion proteins and the Rho-GTPase protein family (RhoA, Rac1, and Cdc42) in Ang II-mediated MSC migration. Cell adhesion proteins (FAK, Talin, and Vinculin) were detected by western blot analysis. The Rho-GTPase family protein activities were assessed by G-LISA and F-actin levels, which reflect actin cytoskeletal organization, were detected by using immunofluorescence. Human bone marrow MSCs constitutively expressed AT1R and AT2R. Additionally, Ang II increased MSC migration in an AT2R-dependent manner. Notably, Ang II-enhanced migration was not mediated by Ang II-mediated cell proliferation. Interestingly, Ang II-enhanced migration was mediated by FAK activation, which was critical for the formation of focal contacts, as evidenced by increased Talin and Vinculin expression. Moreover, RhoA and Cdc42 were activated by FAK to increase cytoskeletal organization, thus promoting cell contraction. Furthermore, FAK, Talin, and Vinculin activation and F-actin reorganization in response to Ang II were prevented by PD-123319 but not Losartan, indicating that FAK activation and F-actin reorganization were downstream of AT2R. These data indicate that Ang II-AT2R regulates human bone marrow MSC migration by signaling through the FAK and RhoA/Cdc42 pathways. This study provides insights into the mechanisms by which MSCs home to injury sites and will enable the rational design of targeted therapies to improve MSC engraftment.

n/a

NASA Image and Video Library

1971-08-01

The Apollo Telescope Mount (ATM), designed and developed by the Marshall Space Flight Center, was one of four major components comprising the Skylab (1973-1979). The ATM housed the first manned scientific telescope in space. This photograph is of the ATM thermal systems unit undergoing testing in the Space Environment Simulation Laboratory of the Manned Spacecraft Center (MSC). The ATM thermal systems unit was used to control the temperatures of space instrument's subsystems during a mission. The MSC was renamed the Johnson Space Center (JSC) in early 1973.

Softwaremodule voor het Simuleren van de Gevolgen van Raketonderschepping (The Dutch Program for the Simulation of Missile Intercept Effects)

DTIC Science & Technology

2007-07-01

effects (Softwaremodule voor het simuleren van de gevolgen van raketonderschepping) 11 . AUTHOR(S) Dr E. Abadjieva, MSc R.P. Sterkenburg, MSc F. Bouquet...Softwaremnodule voor het simuleren van de gevolgen van raketonderschepping D)attini Juli 2007 Auteur(s) dr. F. Abadjicva ir. R.P Sterkenburg ir. F. Bouquet ir...P.W. D)ouip Rubricering rapport O)ngerubri ceerd Vastgesteld door Maj R. 11 . Jongkinid Vastgesteld d.d. 12 juni 2007 (Deze nitining mizil-4 sict

[Influence of human mesenchymal stem cells on hyperoxia-exposed newborn rats by RAGE-NF-κB signaling in lung].

PubMed

Tian, Zhao-fang; Ji, Ping; Li, Yu-hong; Zhao, Sai; Wang, Xiang

2012-05-01

To investigate the influence of high oxygen exposure on signaling pathway of the receptor for advanced glycation end products (RAGE)-NF-κB of lung in newborn rats and the mechanisms of protecting lung injury for human mesenchymal stem cells (hMSC). Twenty-four newborn Sprague-Dawley rats from three litters were randomly divided into three groups, as hyperoxia exposed + hMSC group (group A), hyperoxia exposed group (group B), and air-exposed group (group C). The rats from the group A and B were placed in a sealed Plexiglas chamber with a minimal in-and outflow, providing six to seven exchanges per hour of the chamber volume and maintaining O(2) levels above 95%, while rats in the group C only exposed to air simultaneously. Seven days later, rats in the group A were injected intravenously with hMSC (5×10(4)) after hyperoxia exposure, but rats in group B and C received subcutaneous injection with PBS alone at the same time point. Then all the rats were exposed to air, and were sacrificed three days later. Immunohistochemistry was used to evaluate the expression of RAGE in lung tissue. The levels of TNF-α and sRAGE in bronchoalveolar lavage fluid (BALF) and in serum were detected by ELASA, RAGE mRNA and NF-κB mRNA in tissue homogenates were detected by RT-PCR, RAGE and NF-κB by Western blotting; also the value of lung damage score were calculated with histology under light microscope. There were significant differences among three groups in the fields of lung damage score (F = 51.59, P = 0.000), mRNA and protein of RAGE (F = 37.21, P = 0.000; F = 15.88, P = 0.000) and NF-κB (F = 5.695, P = 0.011; F = 4.223, P = 0.0288) in lung tissue homogenates, and the level of TNF-α (F = 38.29, P = 0.000) in BALF, all these parameters in group A and group B were higher than that in group C. While sRAGE in BALF in group A and group B were less than that in group C (F = 4.804, P = 0.0191). There were also significant differences between group A and group B in these parameters (P < 0.05). There were also no significant differences neither in TNF-α nor in sRAGE in serum among three groups. hMSC protects hyperoxia-induced lung injury via downregulating the signaling pathway of RAGE-NF-κB.

Mechanosensitive Channel MscS in the Open State: Modeling of the Transition, Explicit Simulations, and Experimental Measurements of Conductance

PubMed Central

Anishkin, Andriy; Kamaraju, Kishore; Sukharev, Sergei

2008-01-01

Mechanosensitive channels of small conductance (MscS) are ubiquitous turgor pressure regulators found in many walled cells and some intracellular organelles. Escherichia coli MscS acting as a tension-activated osmolyte release valve shows a nonsaturable conductance (1.2 nS in a 39 mS/cm electrolyte) and weak preference for anions. Pursuing the transition pathways in this channel, we applied the extrapolated motion protocol (cycles of displacements, minimizations, and short simulations) to the previously generated compact resting conformation of MscS. We observed tilting and straightening of the kinked pore-forming TM3 helices during the barrel expansion. Extended all-atom simulations confirmed the stability of the open conformation in the bilayer. A 53° spontaneous axial rotation of TM3s observed after equilibration increased the width and polarity of the pore allowing for stable voltage-independent hydration and presence of both cations and anions throughout the pore. The resultant open state, characterized by a pore 1.6 nm wide, satisfied the experimental conductance and in-plane expansion. Applied transmembrane electric field (±100 to ±200 mV) in simulations produced a flow of both K+ and Cl−, with Cl− current dominating at higher voltages. Electroosmotic water flux strongly correlated with the chloride current (∼8 waters per Cl−). The selectivity and rectification were in agreement with the experimental measurements performed in the same range of voltages. Among the charged residues surrounding the pore, only K169 was found to contribute noticeably in the rectification. We conclude that (a) the barrel expansion involving tilting, straightening, and rotation of TM3s provides the geometry and electrostatics that accounts for the conductive properties of the open pore; (b) the observed regimen of ion passage through the pore is similar to electrodiffusion, thus macroscopic estimations closely approximate the experimental and molecular dynamics-simulated conductances; (c) increased interaction of the opposing ionic fluxes at higher voltages may result in selectivities stronger than measured near the reversal potential. PMID:18591417

Gating Mechanisms of Mechanosensitive Channels of Large Conductance, I: A Continuum Mechanics-Based Hierarchical Framework

PubMed Central

Chen, Xi; Cui, Qiang; Tang, Yuye; Yoo, Jejoong; Yethiraj, Arun

2008-01-01

A hierarchical simulation framework that integrates information from molecular dynamics (MD) simulations into a continuum model is established to study the mechanical response of mechanosensitive channel of large-conductance (MscL) using the finite element method (FEM). The proposed MD-decorated FEM (MDeFEM) approach is used to explore the detailed gating mechanisms of the MscL in Escherichia coli embedded in a palmitoyloleoylphosphatidylethanolamine lipid bilayer. In Part I of this study, the framework of MDeFEM is established. The transmembrane and cytoplasmic helices are taken to be elastic rods, the loops are modeled as springs, and the lipid bilayer is approximated by a three-layer sheet. The mechanical properties of the continuum components, as well as their interactions, are derived from molecular simulations based on atomic force fields. In addition, analytical closed-form continuum model and elastic network model are established to complement the MDeFEM approach and to capture the most essential features of gating. In Part II of this study, the detailed gating mechanisms of E. coli-MscL under various types of loading are presented and compared with experiments, structural model, and all-atom simulations, as well as the analytical models established in Part I. It is envisioned that such a hierarchical multiscale framework will find great value in the study of a variety of biological processes involving complex mechanical deformations such as muscle contraction and mechanotransduction. PMID:18390626

Force transduction and lipid binding in MscL: A continuum-molecular approach

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vanegas, Juan M.; Arroyo, Marino; Fotiadis, Dimitrios

2014-12-01

The bacterial mechanosensitive channel MscL, a small protein mainly activated by membrane tension, is a central model system to study the transduction of mechanical stimuli into chemical signals. Mutagenic studies suggest that MscL gating strongly depends on both intra-protein and interfacial lipid-protein interactions. However, there is a gap between this detailed chemical information and current mechanical models of MscL gating. Here, we investigate the MscL bilayer-protein interface through molecular dynamics simulations, and take a combined continuum-molecular approach to connect chemistry and mechanics. We quantify the effect of membrane tension on the forces acting on the surface of the channel, andmore » identify interactions that may be critical in the force transduction between the membrane and MscL. We find that the local stress distribution on the protein surface is largely asymmetric, particularly under tension, with the cytoplasmic side showing significantly larger and more localized forces, which pull the protein radially outward. The molecular interactions that mediate this behavior arise from hydrogen bonds between the electronegative oxygens in the lipid headgroup and a cluster of positively charged lysine residues on the amphipathic S1 domain and the C-terminal end of the second trans-membrane helix. We take advantage of this strong interaction (estimated to be 10–13 kT per lipid) to actuate the channel (by applying forces on protein-bound lipids) and explore its sensitivity to the pulling magnitude and direction. We conclude by highlighting the simple motif that confers MscL with strong anchoring to the bilayer, and its presence in various integral membrane proteins including the human mechanosensitive channel K2P1 and bovine rhodopsin.« less

Representing the Seasonal Variation of Marine Stratus and Stratocumulus near the Western Coast of Continents

NASA Astrophysics Data System (ADS)

He, Y.; Dickinson, R.

2005-12-01

The seasonal variation of marine stratus and stratocumulus (MSC) plays a significant role in ocean- atmosphere-land interaction during the seasonal transition of basic climate in the Eastern Pacific. A key factor in parameterization of MSC cloud cover is atmospheric stability. In this study, we examine the importance of lower troposphere stability for Marine Stratus and Stratocumulus (MSC) cloud cover variations over subtropical oceans on monthly and seasonal timescales. Our approach is to consider a two-layer conceptual model with moist denser boundary layer air topped by dry lighter free air beneath a trade wind inversion at around 700 mb.The vertical integrated dry static energy is of central importance in the lower troposphere. The variation of dry static energy transport and latent heat release leads to the variation of cloud top radiative forcing, which is a function of low cloud cover. A diagnostic cloud cover scheme derived from the model is a nonlinear function of lower troposphere stability and large-scale subsidence. Use ERA-40 and ISCCP-FD data as input, the scheme reproduces well the seasonal variation of low cloud cover in four MSC regions near the western coast of continents. NCAR CAM linear empirical cloud cover scheme could explain 16% of the observed ISCCP monthly covariance in the southeast subtropical Pacific during 1990 to 2000 period; while the new cloud cover scheme could explain 50% of the total covariance. When implementing new scheme into NCAR CAM3.1, it is found that the seasonal phase of MSC is better simulated near the Peruvian region, but the seasonal amplitudes of MSC cloud cover in four MSC regions using both schemes have systematic problems. Possible causes for model cloud biases are investigated through numerical experiments. The importance of MSC cloud cover in the eastern Pacific on local mean climate is also discussed.

A prediction of cell differentiation and proliferation within a collagen-glycosaminoglycan scaffold subjected to mechanical strain and perfusive fluid flow.

PubMed

Stops, A J F; Heraty, K B; Browne, M; O'Brien, F J; McHugh, P E

2010-03-03

Mesenchymal stem cell (MSC) differentiation can be influenced by biophysical stimuli imparted by the host scaffold. Yet, causal relationships linking scaffold strain magnitudes and inlet fluid velocities to specific cell responses are thus far underdeveloped. This investigation attempted to simulate cell responses in a collagen-glycosaminoglycan (CG) scaffold within a bioreactor. CG scaffold deformation was simulated using micro-computed tomography (CT) and an in-house finite element solver (FEEBE/linear). Similarly, the internal fluid velocities were simulated using the afore-mentioned microCT dataset with a computational fluid dynamics solver (ANSYS/CFX). From the ensuing cell-level mechanics, albeit octahedral shear strain or fluid velocity, the proliferation and differentiation of the representative cells were predicted from deterministic functions. Cell proliferation patterns concurred with previous experiments. MSC differentiation was dependent on the level of CG scaffold strain and the inlet fluid velocity. Furthermore, MSC differentiation patterns indicated that specific combinations of scaffold strains and inlet fluid flows cause phenotype assemblies dominated by single cell types. Further to typical laboratory procedures, this predictive methodology demonstrated loading-specific differentiation lineages and proliferation patterns. It is hoped these results will enhance in-vitro tissue engineering procedures by providing a platform from which the scaffold loading applications can be tailored to suit the desired tissue. Copyright 2009 Elsevier Ltd. All rights reserved.

FEM and Multiphysics Applications at NASA/GSFC

NASA Technical Reports Server (NTRS)

Loughlin, James

2004-01-01

FEM software available to the Mechanical Systems Analysis and Simulation Branch at Goddard Space Flight Center (GSFC) include: 1) MSC/Nastran; 2) Abaqus; 3) Ansys/Multiphysics; 4) COSMOS/M; 5) 'Home-grown' programs; 6) Pre/post processors such as Patran and FEMAP. This viewgraph presentation provides additional information on MSC/Nastran and Ansys/Multiphysics, and includes screen shots of analyzed equipment, including the Wilkinson Microwave Anistropy Probe, a micro-mirror, a MEMS tunable filter, and a micro-shutter array. The presentation also includes information on the verification of results.

Skylab (SL)-4 Astronauts - "Open House" Press Day - SL Mockup - MSC

NASA Image and Video Library

1972-01-20

S72-17512 (19 Jan. 1972) --- These three men are the crewmen for the first manned Skylab mission. They are astronaut Charles Conrad Jr., commander, standing left; scientist-astronaut Joseph P. Kerwin, seated; and astronaut Paul J. Weitz, pilot. They were photographed and interviewed during an "open house" press day in the realistic atmosphere of the Multiple Docking Adapter (MDA) trainer in the Mission Simulation and Training Facility at the Manned Spacecraft Center (MSC). The control and display panel for the Apollo Telescope Mount (ATM) is at right. Photo credit: NASA

Evaluating the feasibility of global climate models to simulate cloud cover effect controlled by Marine Stratocumulus regime transitions

NASA Astrophysics Data System (ADS)

Goren, Tom; Muelmenstaedt, Johannes; Rosenfeld, Daniel; Quaas, Johannes

2017-04-01

Marine stratocumulus clouds (MSC) occur in two main cloud regimes of open and closed cells that differ significantly by their cloud cover. Closed cells gradually get cleansed of high CCN concentrations in a process that involves initiation of drizzle that breaks the full cloud cover into open cells. The drizzle creates downdrafts that organize the convection along converging gust fronts, which in turn produce stronger updrafts that can sustain more cloud water that compensates the depletion of the cloud water by the rain. In addition, having stronger updrafts allow the clouds to grow relatively deep before rain starts to deplete its cloud water. Therefore, lower droplet concentrations and stronger rain would lead to lower cloud fraction, but not necessary also to lower liquid water path (LWP). The fundamental relationships between these key variables derived from global climate model (GCM) simulations are analyzed with respect to observations in order to determine whether the GCM parameterizations can represent well the governing physical mechanisms upon MSC regime transitions. The results are used to evaluate the feasibility of GCM's for estimating aerosol cloud-mediated radiative forcing upon MSC regime transitions, which are responsible for the largest aerosol cloud-mediated radiative forcing.

Theory and Application of Photoelectron Diffraction for Complex Oxide Systems

NASA Astrophysics Data System (ADS)

Chassé, Angelika; Chassé, Thomas

2018-06-01

X-ray photoelectron diffraction (XPD) has been used to investigate film structures and local sites of surface and dopant atoms in complex oxide materials. We have performed angular-resolved measurements of intensity distribution curves (ADCs) and patterns (ADPs) of elemental core level intensities from binary to quaternary mixed oxide samples and compared them to multiple-scattering cluster (MSC) calculations in order to derive information on structural models and related parameters. MSC calculations permitted to describe both bulk diffraction features of binary oxide MnO(001) and the thickness-dependence of the tetragonal distortion of epitaxial MnO films on Ag(001). XPD was further used to investigate the surface termination of perovskite SrTiO3 and BaTiO3 substrates in order to evaluate influence of different ex situ and in situ preparation procedures on the surface layers, which are crucial for quality of following film growth. Despite the similarity of local environments of Sr (Ba) and Ti atoms in the perovskite film structure an angular region in the ADCs was identified as a fingerprint with the help of MSC simulations which provided clear conclusions on the perovskite oxide surfaces. Dopant sites in quaternary perovskite manganites La1-xCaxMnO3, La1-xSrxMnO3, and La1-xCexMnO3 were studied with polar angle scans of the photoemission intensities of host and dopant atoms. Both direct comparison of experimental ADCs and to the simulations within MSC models confirm the occupation of A sites by the dopants and the structural quality of the complex oxide films.

LUNAR SAMPLES - APOLLO 11 - MSC

NASA Image and Video Library

1969-07-28

S69-45025 (27 July 1969) --- This is the first lunar sample that was photographed in detail in the Lunar Receiving Laboratory at the Manned Spacecraft Center. The photograph shows a granular, fine-grained, mafic (iron magnesium rich) rock. At this early stage of the examination, this rock appears similar to several igneous rock types found on Earth. The scale is printed backwards due to the photographic configuration in the Vacuum Chamber. The sample number is 10003. This rock was among the samples collected by astronauts Neil A. Armstrong and Edwin E. Aldrin Jr. during their lunar surface extravehicular activity on July 20, 1969.

FAST Mast Structural Response to Axial Loading: Modeling and Verification

NASA Technical Reports Server (NTRS)

Knight, Norman F., Jr.; Elliott, Kenny B.; Templeton, Justin D.; Song, Kyongchan; Rayburn, Jeffery T.

2012-01-01

The International Space Station s solar array wing mast shadowing problem is the focus of this paper. A building-block approach to modeling and analysis is pursued for the primary structural components of the solar array wing mast structure. Starting with an ANSYS (Registered Trademark) finite element model, a verified MSC.Nastran (Trademark) model is established for a single longeron. This finite element model translation requires the conversion of several modeling and analysis features for the two structural analysis tools to produce comparable results for the single-longeron configuration. The model is then reconciled using test data. The resulting MSC.Nastran (Trademark) model is then extended to a single-bay configuration and verified using single-bay test data. Conversion of the MSC. Nastran (Trademark) single-bay model to Abaqus (Trademark) is also performed to simulate the elastic-plastic longeron buckling response of the single bay prior to folding.

Skylab 2 crew during "open house" press day at Manned Spacecraft Center (MSC)

NASA Image and Video Library

1972-01-19

S72-17509 (19 Jan. 1972) --- These three men are the crewmen for the first manned Skylab mission. They are astronaut Charles Conrad Jr., commander, standing left; scientist-astronaut Joseph P. Kerwin, seated; and astronaut Paul J. Weitz, pilot. They were photographed and interviewed during an "open house" press day in the realistic atmosphere of the Multiple Docking Adapter (MDA) trainer in the Mission Simulation and Training Facility at the Manned Spacecraft Center (MSC). The control and display panel for the Apollo Telescope Mount (ATM) is at right. Photo credit: NASA

Computational fluid dynamic (CFD) investigation of thermal uniformity in a thermal cycling based calibration chamber for MEMS

NASA Astrophysics Data System (ADS)

Gui, Xulong; Luo, Xiaobing; Wang, Xiaoping; Liu, Sheng

2015-12-01

Micro-electrical-mechanical system (MEMS) has become important for many industries such as automotive, home appliance, portable electronics, especially with the emergence of Internet of Things. Volume testing with temperature compensation has been essential in order to provide MEMS based sensors with repeatability, consistency, reliability, and durability, but low cost. Particularly, in the temperature calibration test, temperature uniformity of thermal cycling based calibration chamber becomes more important for obtaining precision sensors, as each sensor is different before the calibration. When sensor samples are loaded into the chamber, we usually open the door of the chamber, then place fixtures into chamber and mount the samples on the fixtures. These operations may affect temperature uniformity in the chamber. In order to study the influencing factors of sample-loading on the temperature uniformity in the chamber during calibration testing, numerical simulation work was conducted first. Temperature field and flow field were simulated in empty chamber, chamber with open door, chamber with samples, and chamber with fixtures, respectively. By simulation, it was found that opening chamber door, sample size and number of fixture layers all have effects on flow field and temperature field. By experimental validation, it was found that the measured temperature value was consistent with the simulated temperature value.

Multi-stage high cell continuous fermentation for high productivity and titer.

PubMed

Chang, Ho Nam; Kim, Nag-Jong; Kang, Jongwon; Jeong, Chang Moon; Choi, Jin-dal-rae; Fei, Qiang; Kim, Byoung Jin; Kwon, Sunhoon; Lee, Sang Yup; Kim, Jungbae

2011-05-01

We carried out the first simulation on multi-stage continuous high cell density culture (MSC-HCDC) to show that the MSC-HCDC can achieve batch/fed-batch product titer with much higher productivity to the fed-batch productivity using published fermentation kinetics of lactic acid, penicillin and ethanol. The system under consideration consists of n-serially connected continuous stirred-tank reactors (CSTRs) with either hollow fiber cell recycling or cell immobilization for high cell-density culture. In each CSTR substrate supply and product removal are possible. Penicillin production is severely limited by glucose metabolite repression that requires multi-CSTR glucose feeding. An 8-stage C-HCDC lactic acid fermentation resulted in 212.9 g/L of titer and 10.6 g/L/h of productivity, corresponding to 101 and 429% of the comparable lactic acid fed-batch, respectively. The penicillin production model predicted 149% (0.085 g/L/h) of productivity in 8-stage C-HCDC with 40 g/L of cell density and 289% of productivity (0.165 g/L/h) in 7-stage C-HCDC with 60 g/L of cell density compared with referring batch cultivations. A 2-stage C-HCDC ethanol experimental run showed 107% titer and 257% productivity of the batch system having 88.8 g/L of titer and 3.7 g/L/h of productivity. MSC-HCDC can give much higher productivity than batch/fed-batch system, and yield a several percentage higher titer as well. The productivity ratio of MSC-HCDC over batch/fed-batch system is given as a multiplication of system dilution rate of MSC-HCDC and cycle time of batch/fed-batch system. We suggest MSC-HCDC as a new production platform for various fermentation products including monoclonal antibody.

Compact, Automated Centrifugal Slide-Staining System

NASA Technical Reports Server (NTRS)

Feeback, Daniel L.; Clarke, Mark S. F.

2004-01-01

The Directional Acceleration Vector-Driven Displacement of Fluids (DAVD-DOF) system, under development at the time of reporting the information for this article, would be a relatively compact, automated, centrifugally actuated system for staining blood smears and other microbiological samples on glass microscope slides in either a microgravitational or a normal Earth gravitational environment. The DAVD-DOF concept is a successor to the centrifuge-operated slide stainer (COSS) concept, which was reported in Slide-Staining System for Microgravity or Gravity (MSC-22949), NASA Tech Briefs, Vol. 25, No. 1 (January, 2001), page 64. The COSS includes reservoirs and a staining chamber that contains a microscope slide to which a biological sample is affixed. The staining chamber is sequentially filled with and drained of staining and related liquids from the reservoirs by use of a weighted plunger to force liquid from one reservoir to another at a constant level of hypergravity maintained in a standard swing-bucket centrifuge. In the DAVD-DOF system, a staining chamber containing a sample would also be sequentially filled and emptied, but with important differences. Instead of a simple microscope slide, one would use a special microscope slide on which would be fabricated a network of very small reservoirs and narrow channels connected to a staining chamber (see figure). Unlike in the COSS, displacement of liquid would be effected by use of the weight of the liquid itself, rather than the weight of a plunger.

Discharge Chamber Primary Electron Modeling Activities in Three-Dimensions

NASA Technical Reports Server (NTRS)

Steuber, Thomas J.

2004-01-01

Designing discharge chambers for ion thrusters involves many geometric configuration decisions. Various decisions will impact discharge chamber performance with respect to propellant utilization efficiency, ion production costs, and grid lifetime. These hardware design decisions can benefit from the assistance of computational modeling. Computational modeling for discharge chambers has been limited to two-dimensional codes that leveraged symmetry for interpretation into three-dimensional analysis. This paper presents model development activities towards a three-dimensional discharge chamber simulation to aid discharge chamber design decisions. Specifically, of the many geometric configuration decisions toward attainment of a worthy discharge chamber, this paper focuses on addressing magnetic circuit considerations with a three-dimensional discharge chamber simulation as a tool. With this tool, candidate discharge chamber magnetic circuit designs can be analyzed computationally to gain insight into factors that may influence discharge chamber performance such as: primary electron loss width in magnetic cusps, cathode tip position with respect to the low magnetic field volume, definition of a low magnetic field region, and maintenance of a low magnetic field region across the grid span. Corroborating experimental data will be obtained from mockup hardware tests. Initially, simulated candidate magnetic circuit designs will resemble previous successful thruster designs. To provide opportunity to improve beyond previous performance benchmarks, off-design modifications will be simulated and experimentally tested.

Apollo 16 astronauts in Apollo Command Module Mission Simulator

NASA Technical Reports Server (NTRS)

1972-01-01

Astronaut Thomas K. Mattingly II, command module pilot of the Apollo 16 lunar landing mission, participates in extravehicular activity (EVA) training in bldg 5 at the Manned Spacecraft Center (MSC). In the right background is Astronaut Charles M. Duke Jr., lunar module pilot. They are inside the Apollo Command Module Mission Simulator (31046); Mattingly (right foreground) and Duke (right backgroung) in the Apollo Command Module Mission Simulator for EVA simulation and training. Astronaut John W. Young, commander, can be seen in the left background (31047).

[Basic biological characteristics of mesenchymal stem cells derived from bone marrow and human umbilical cord].

PubMed

Han, Zhen-Xia; Shi, Qing; Wang, Da-Kun; Li, Dong; Lyu, Ming

2013-10-01

Bone marrow (BM) and umbilical cord (UC) are the major sources of mesenchymal stem cells for therapeutics. This study was aimed to compare the basic biologic characteristics of bone marrow-derived and umbilical cord derived-mesenchymal stem cells (BM-MSC and UC-MSC) and their immunosuppressive capability in vitro. The BM-MSC and UC-MSC were cultured and amplified under same culture condition. The growth kinetics, phenotypic characteristics and immunosuppressive effects of UC-MSC were compared with those of BM-MSC.Gene chip was used to compare the genes differentially expressed between UC-MSC and BM-MSC. The results showed that UC-MSC shared most of the characteristics of BM-MSC, including morphology and immunophenotype. UC-MSC could be ready expanded for 30 passages without visible changes. However, BM-MSC grew slowly, and the mean doubling time increased notably after passage 6. Both UC-MSC and BM-MSC could inhibit phytohemagglutinin-stimulated peripheral blood mononuclear cell proliferation, in which BM-MSC mediated more inhibitory effect. Compared with UC-MSC, BM-MSC expressed more genes associated with immune response. Meanwhile, the categories of up-regulated genes in UC-MSC were concentrated in organ development and growth. It is concluded that the higher proliferation capacity, low human leukocyte antigen-ABC expression and immunosuppression make UC-MSC an excellent alternative to BM-MSC for cell therapy. The differences between BM-MSC and UC-MSC gene expressions can be explained by their ontogeny and different microenvironment in origin tissue. These differences can affect their efficacy in different therapeutic applications.

Ovariectomized Rats with Established Osteopenia have Diminished Mesenchymal Stem Cells in the Bone Marrow and Impaired Homing, Osteoinduction and Bone Regeneration at the Fracture Site.

PubMed

Tewari, Deepshikha; Khan, Mohd Parvez; Sagar, Nitin; China, Shyamsundar P; Singh, Atul K; Kheruka, Subhash C; Barai, Sukanta; Tewari, Mahesh C; Nagar, Geet K; Vishwakarma, Achchhe L; Ogechukwu, Omeje E; Bellare, Jayesh R; Gambhir, Sanjay; Chattopadhyay, Naibedya

2015-04-01

We investigated deleterious changes that take place in mesenchymal stem cells (MSC) and its fracture healing competence in ovariectomy (Ovx)-induced osteopenia. MSC from bone marrow (BM) of ovary intact (control) and Ovx rats was isolated. (99m)Tc-HMPAO (Technitium hexamethylpropylene amine oxime) labeled MSC was systemically transplanted to rats and fracture tropism assessed by SPECT/CT. PKH26 labeled MSC (PKH26-MSC) was bound in scaffold and applied to fracture site (drill-hole in femur metaphysis). Osteoinduction was quantified by calcein binding and microcomputed tomography. Estrogen receptor (ER) antagonist, fulvestrant was used to determine ER dependence of osteo-induction by MSC. BM-MSC number was strikingly reduced and doubling time increased in Ovx rats compared to control. SPECT/CT showed reduced localization of (99m)Tc-HMPAO labeled MSC to the fracture site, 3 h post-transplantation in Ovx rats as compared with controls. Post-transplantation, Ovx MSC labeled with PKH26 (Ovx PKH26-MSC) localized less to fracture site than control PKH26-MSC. Transplantation of either control or Ovx MSC enhanced calcein binding and bone volume at the callus of control rats over placebo group however Ovx MSC had lower efficacy than control MSC. Fulvestrant blocked osteoinduction by control MSC. When scaffold bound MSC was applied to fracture, osteoinduction by Ovx PKH26-MSC was less than control PKH26-MSC. In Ovx rats, control MSC/E2 treatment but not Ovx MSC showed osteoinduction. Regenerated bone was irregularly deposited in Ovx MSC group. In conclusion, Ovx is associated with diminished BM-MSC number and its growth, and Ovx MSC displays impaired engraftment to fracture and osteoinduction besides disordered bone regeneration.

Astronaut Robert Crippen holds training model of Skylab experiment

NASA Image and Video Library

1972-06-15

S72-43280 (15 June 1972) --- Astronaut Robert L. Crippen, Skylab Medical Experiment Altitude Test (SMEAT) commander, holds the training model of Skylab experiment T003, the aerosol analysis test, in this preview of SMEAT activity. He is part of a three-man SMEAT crew who will spend up to 56 days in the Crew Systems Division's 20-foot altitude chamber at the NASA Manned Spacecraft Center (MSC) beginning in mid-July to obtain medical data and evaluate medical experiment equipment for Skylab. The two crew members not shown in this view are astronauts Karol J. Bobko, SMEAT pilot, and Dr. William E. Thornton, SMEAT science pilot. Photo credit: NASA

The Mobile Chamber

NASA Technical Reports Server (NTRS)

Scharfstein, Gregory; Cox, Russell

2012-01-01

A document discusses a simulation chamber that represents a shift from the thermal-vacuum chamber stereotype. This innovation, currently in development, combines the capabilities of space simulation chambers, the user-friendliness of modern-day electronics, and the modularity of plug-and-play computing. The Mobile Chamber is a customized test chamber that can be deployed with great ease, and is capable of bringing payloads at temperatures down to 20 K, in high vacuum, and with the desired metrology instruments integrated to the systems control. Flexure plans to lease Mobile Chambers, making them affordable for smaller budgets and available to a larger customer base. A key feature of this design will be an Apple iPad-like user interface that allows someone with minimal training to control the environment inside the chamber, and to simulate the required extreme environments. The feedback of thermal, pressure, and other measurements is delivered in a 3D CAD model of the chamber's payload and support hardware. This GUI will provide the user with a better understanding of the payload than any existing thermal-vacuum system.

Small hydrogen/oxygen rocket flowfield behavior from heat flux measurements

NASA Technical Reports Server (NTRS)

Reed, Brian D.

1993-01-01

The mixing and heat transfer phenomena in small rocket flow fields with fuel film cooling is not well understood. An instrumented, water-cooled chamber with a gaseous hydrogen/gaseous oxygen injector was used to gather steady-state inner and outer wall temperature profiles. The chamber was tested at 414 kPa (60 psia) chamber pressure, from mixture ratios of 3.41 to 8.36. Sixty percent of the fuel was used for film cooling. These temperature profiles were used as boundary conditions in a finite element analysis program, MSC/NASTRAN, to calculate the local radial and axial heat fluxes in the chamber wall. The normal heat fluxes were then calculated and used as a diagnostic of the rocket's flow field behavior. The normal heat fluxes determined were on the order of 1.0 to 3.0 MW/meters squared (0.6 to 1.8 Btu/sec-inches squared). In the cases where mixture ratio was 5 or above, there was a sharp local heat flux maximum in the barrel section of the chamber. This local maximum seems to indicate a reduction or breakdown of the fuel film cooling layer, possibly due to increased mixing in the shear layer between the film and core flows. However, the flow was thought to be completely laminar, as the throat Reynolds numbers were below 50,000 for all the cases. The increased mixing in the shear layer in the higher mixture ratio cases appeared not to be due to the transition of the flow from laminar to turbulent, but rather due to increased reactions between the hydrogen film and oxidizer-rich core flows.

Ultra-Wide Field Imaging in Paradoxical Worsening of Tubercular Multifocal Serpiginoid Choroiditis after the Initiation of Anti-Tubercular Therapy.

PubMed

Aggarwal, Kanika; Agarwal, Aniruddha; Deokar, Ankit; Singh, Ramandeep; Bansal, Reema; Sharma, Aman; Sharma, Kusum; Dogra, Mangat R; Gupta, Vishali

2017-10-11

To evaluate role of ultra-wide field (UWF) versus conventional imaging in the follow-up and paradoxical worsening (PW) of tubercular (TB) multifocal serpiginoid choroiditis (MSC). Prospective observational study of patients with TB MSC undergoing UWF imaging, autofluorescence and fluorescein angiography was performed. A circle simulating central 75° field representing conventional imaging was drawn on UWF images. The information yielded by the two modalities, progression of choroiditis lesions and PW was compared. 44 eyes (29 patients, mean age: 30.7 ± 9 years; 23 males) were included. UWF imaging showed additional lesions in 39/44 eyes (88.6%). Overall, 16/44 eyes (36.4%) showed PW; 3/16 eyes (18.7%) showed only peripheral PW, while 10/16 eyes showed both central and peripheral PW. Management was altered in 11 patients (37.93%) based on UWF imaging. UWF is more useful than conventional imaging in identifying additional choroiditis lesions, PW and altering the course of therapy in TB MSC.

TLR4 plays a crucial role in MSC-induced inhibition of NK cell function

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lu, Ying; Liu, Jin; Liu, Yang

2015-08-21

Mesenchymal stem cells (MSC) are a kind of stromal cell within the tumor microenvironment. In our research, MSC derived from acute myeloid leukemia patients' bone marrow (AML-MSC) and lung cancer tissues (LC-MSC) as well as normal bone marrow-derived MSC (BM-MSC) cultured in conditioned medium of HeLa cells were found to have higher expressions of Toll-like receptor (TLR4) mRNA compared with BM-MSC. The sorted TLR4-positive MSC (TLR4+ MSC) differed in cytokine (interleukin-6, interleukin-8, and monocyte chemoattractant protein-1) secretion from those of unsorted MSC. MSC was reported to inhibit natural killer (NK) cell proliferation and function. In this research, we confirmed thatmore » TLR4+ MSC aggravate this suppression. Furthermore, when TLR4 in the sorted cells were stimulated by LPS or following blocked by antibody, the suppression on NK cell proliferation and cytotoxicity were more intensive or recovered respectively. Compared to unsorted MSC, NKG2D receptor expression on NK cells were also inhibited by TLR4+ MSC. These findings suggest that activation of TLR4 pathway is important for TLR4+ MSC and MSC to obstruct anti-tumor immunity by inhibiting NK cell function, which may provide a potential stroma-targeted tumor therapy. - Highlights: • TLR4+ MSC inhibit NK cell proliferation in vivo and in vitro. • TLR4+ MSC inhibit NKG2D expression on NK cells and NK cell cytotoxicity. • The distinguished cytokine expression of TLR4+ MSC may contribute to the inhibition on NK cell function.« less

A new plant chamber facility PLUS coupled to the atmospheric simulation chamber SAPHIR

NASA Astrophysics Data System (ADS)

Hohaus, T.; Kuhn, U.; Andres, S.; Kaminski, M.; Rohrer, F.; Tillmann, R.; Wahner, A.; Wegener, R.; Yu, Z.; Kiendler-Scharr, A.

2015-11-01

A new PLant chamber Unit for Simulation (PLUS) for use with the atmosphere simulation chamber SAPHIR (Simulation of Atmospheric PHotochemistry In a large Reaction Chamber) has been build and characterized at the Forschungszentrum Jülich GmbH, Germany. The PLUS chamber is an environmentally controlled flow through plant chamber. Inside PLUS the natural blend of biogenic emissions of trees are mixed with synthetic air and are transferred to the SAPHIR chamber where the atmospheric chemistry and the impact of biogenic volatile organic compounds (BVOC) can be studied in detail. In PLUS all important enviromental parameters (e.g. temperature, PAR, soil RH etc.) are well-controlled. The gas exchange volume of 9.32 m3 which encloses the stem and the leafes of the plants is constructed such that gases are exposed to FEP Teflon film and other Teflon surfaces only to minimize any potential losses of BVOCs in the chamber. Solar radiation is simulated using 15 LED panels which have an emission strength up to 800 μmol m-2 s-1. Results of the initial characterization experiments are presented in detail. Background concentrations, mixing inside the gas exchange volume, and transfer rate of volatile organic compounds (VOC) through PLUS under different humidity conditions are explored. Typical plant characteristics such as light and temperature dependent BVOC emissions are studied using six Quercus Ilex trees and compared to previous studies. Results of an initial ozonolysis experiment of BVOC emissions from Quercus Ilex at typical atmospheric concentrations inside SAPHIR are presented to demonstrate a typical experimental set up and the utility of the newly added plant chamber.

Position of the prosthesis and the incidence of dislocation following total hip replacement.

PubMed

He, Rong-xin; Yan, Shi-gui; Wu, Li-dong; Wang, Xiang-hua; Dai, Xue-song

2007-07-05

Dislocation is the second most common complication of hip replacement surgery, and impact of the prosthesis is believed to be the fundamental reason. The present study employed Solidworks 2003 and MSC-Nastran software to analyze the three dimensional variables in order to investigate how to prevent dislocation following hip replacement surgery. Computed tomography (CT) imaging was used to collect femoral outline data and Solidworks 2003 software was used to construct the cup model with variabilities. Nastran software was used to evaluate dislocation at different prosthesis positions and different geometrical shapes. Three dimensional movement and results from finite element method were analyzed and the values of dislocation resistance index (DRI), range of motion to impingement (ROM-I), range of motion to dislocation (ROM-D) and peak resisting moment (PRM) were determined. Computer simulation was used to evaluate the range of motion of the hip joint at different prosthesis positions. Finite element analysis showed: (1) Increasing the ratio of head/neck increased the ROM-I values and moderately increased ROM-D and PRM values. Increasing the head size significantly increased PRM and to some extent ROM-I and ROM-D values, which suggested that there would be a greater likelihood of dislocation. (2) Increasing the anteversion angle increased the ROM-I, ROM-D, PRM, energy required for dislocation (ENERGY-D) and DRI values, which would increase the stability of the joint. (3) As the chamber angle was increased, ROM-I, ROM-D, PRM, Energy-D and DRI values were increased, resulting in improved joint stability. Chamber angles exceeding 55 degrees resulted in increases in ROM-I and ROM-D values, but decreases in PRM, Energy-D, and DRI values, which, in turn, increased the likelihood of dislocation. (4) The cup, which was reduced posteriorly, reduced ROM-I values (2.1 -- 5.3 degrees ) and increased the DRI value (0.073). This suggested that the posterior high side had the effect of 10 degrees anteversion angle. Increasing the head/neck ratio increases joint stability. Posterior high side reduced the range of motion of the joint but increased joint stability; Increasing the anteversion angle increases DRI values and thus improve joint stability; Increasing the chamber angle increases DRI values and improves joint stability. However, at angles exceeding 55 degrees , further increases in the chamber angle result in decreased DRI values and reduce the stability of the joint.

Space Simulation Chamber Rescues Water Damaged Books.

ERIC Educational Resources Information Center

American School and University, 1981

1981-01-01

More than 4,000 valuable water-damaged books were restored by using a space-simulation chamber at the Lockheed Missile and Space Company. It was the fifth time that the chamber has been used for the restoration of valuable books and documents. (Author/MLF)

Simulation of Hydrodynamic Ram Phenomenon Using MSC Dytran

DTIC Science & Technology

2014-09-01

impact is unlikely to have detrimental effects on the exit wall of tank due to its rapid extinction in the fluid. The presence of free surface with lower...unlikely to have detrimental effects on the exit wall of tank due to its rapid extinction in the fluid. The presence of free surface with lower...ALE and SPH simulation of the different phases of HRAM, from [13

Animal serum-free culture conditions for isolation and expansion of multipotent mesenchymal stromal cells from human BM.

PubMed

Müller, I; Kordowich, S; Holzwarth, C; Spano, C; Isensee, G; Staiber, A; Viebahn, S; Gieseke, F; Langer, H; Gawaz, M P; Horwitz, E M; Conte, P; Handgretinger, R; Dominici, M

2006-01-01

Multipotent mesenchymal stromal cells (MSC) have become important tools in regenerative and transplantation medicine. Rapidly increasing numbers of patients are receiving in vitro-expanded MSC. Culture conditions typically include FSC because human serum does not fully support growth of human MSC in vitro (MSC(FCS)). Concerns regarding BSE, other infectious complications and host immune reactions have fueled investigation of alternative culture supplements. As PDGF has long been identified as a growth factor for MSC, we tested media supplementation with platelet lysate for support of MSC proliferation. We found that primary cultures of BM-derived MSC can be established with animal serum-free media containing fresh frozen plasma and platelets (MSC(FFPP)). Moreover, MSC(FFPP) showed vigorous proliferation that was superior to classical culture conditions containing FCS. MSC(FFPP) morphology was equivalent to MSC(FCS), and MSC(FFPP) expressed CD73, CD90, CD105, CD106, CD146 and HLA-ABC while being negative for CD34, CD45 and surface HLA-DR, as expected. In addition to being phenotypically identical, MSC(FFPP) could efficiently differentiate into adipocytes and osteoblasts. In terms of immune regulatory properties, MSC(FFPP) were indistinguishable from MSC(FCS). Proliferation of PBMC induced by IL-2 in combination with OKT-3 or by PHA was inhibited in the presence of MSC(FFPP). Taken together, FCS can be replaced safely by FFPP in cultures of MSC for clinical purposes.

A new plant chamber facility, PLUS, coupled to the atmosphere simulation chamber SAPHIR

NASA Astrophysics Data System (ADS)

Hohaus, T.; Kuhn, U.; Andres, S.; Kaminski, M.; Rohrer, F.; Tillmann, R.; Wahner, A.; Wegener, R.; Yu, Z.; Kiendler-Scharr, A.

2016-03-01

A new PLant chamber Unit for Simulation (PLUS) for use with the atmosphere simulation chamber SAPHIR (Simulation of Atmospheric PHotochemistry In a large Reaction Chamber) has been built and characterized at the Forschungszentrum Jülich GmbH, Germany. The PLUS chamber is an environmentally controlled flow-through plant chamber. Inside PLUS the natural blend of biogenic emissions of trees is mixed with synthetic air and transferred to the SAPHIR chamber, where the atmospheric chemistry and the impact of biogenic volatile organic compounds (BVOCs) can be studied in detail. In PLUS all important environmental parameters (e.g., temperature, photosynthetically active radiation (PAR), soil relative humidity (RH)) are well controlled. The gas exchange volume of 9.32 m3 which encloses the stem and the leaves of the plants is constructed such that gases are exposed to only fluorinated ethylene propylene (FEP) Teflon film and other Teflon surfaces to minimize any potential losses of BVOCs in the chamber. Solar radiation is simulated using 15 light-emitting diode (LED) panels, which have an emission strength up to 800 µmol m-2 s-1. Results of the initial characterization experiments are presented in detail. Background concentrations, mixing inside the gas exchange volume, and transfer rate of volatile organic compounds (VOCs) through PLUS under different humidity conditions are explored. Typical plant characteristics such as light- and temperature- dependent BVOC emissions are studied using six Quercus ilex trees and compared to previous studies. Results of an initial ozonolysis experiment of BVOC emissions from Quercus ilex at typical atmospheric concentrations inside SAPHIR are presented to demonstrate a typical experimental setup and the utility of the newly added plant chamber.

Ionization chamber correction factors for MR-linacs

NASA Astrophysics Data System (ADS)

Pojtinger, Stefan; Steffen Dohm, Oliver; Kapsch, Ralf-Peter; Thorwarth, Daniela

2018-06-01

Previously, readings of air-filled ionization chambers have been described as being influenced by magnetic fields. To use these chambers for dosimetry in magnetic resonance guided radiotherapy (MRgRT), this effect must be taken into account by introducing a correction factor k B. The purpose of this study is to systematically investigate k B for a typical reference setup for commercially available ionization chambers with different magnetic field strengths. The Monte Carlo simulation tool EGSnrc was used to simulate eight commercially available ionization chambers in magnetic fields whose magnetic flux density was in the range of 0–2.5 T. To validate the simulation, the influence of the magnetic field was experimentally determined for a PTW30013 Farmer-type chamber for magnetic flux densities between 0 and 1.425 T. Changes in the detector response of up to 8% depending on the magnetic flux density, on the chamber geometry and on the chamber orientation were obtained. In the experimental setup, a maximum deviation of less than 2% was observed when comparing measured values with simulated values. Dedicated values for two MR-linac systems (ViewRay MRIdian, ViewRay Inc, Cleveland, United States, 0.35 T/ 6 MV and Elekta Unity, Elekta AB, Stockholm, Sweden, 1.5 T/7 MV) were determined for future use in reference dosimetry. Simulated values for thimble-type chambers are in good agreement with experiments as well as with the results of previous publications. After further experimental validation, the results can be considered for definition of standard protocols for purposes of reference dosimetry in MRgRT.

Ionization chamber correction factors for MR-linacs.

PubMed

Pojtinger, Stefan; Dohm, Oliver Steffen; Kapsch, Ralf-Peter; Thorwarth, Daniela

2018-06-07

Previously, readings of air-filled ionization chambers have been described as being influenced by magnetic fields. To use these chambers for dosimetry in magnetic resonance guided radiotherapy (MRgRT), this effect must be taken into account by introducing a correction factor k B . The purpose of this study is to systematically investigate k B for a typical reference setup for commercially available ionization chambers with different magnetic field strengths. The Monte Carlo simulation tool EGSnrc was used to simulate eight commercially available ionization chambers in magnetic fields whose magnetic flux density was in the range of 0-2.5 T. To validate the simulation, the influence of the magnetic field was experimentally determined for a PTW30013 Farmer-type chamber for magnetic flux densities between 0 and 1.425 T. Changes in the detector response of up to 8% depending on the magnetic flux density, on the chamber geometry and on the chamber orientation were obtained. In the experimental setup, a maximum deviation of less than 2% was observed when comparing measured values with simulated values. Dedicated values for two MR-linac systems (ViewRay MRIdian, ViewRay Inc, Cleveland, United States, 0.35 T/ 6 MV and Elekta Unity, Elekta AB, Stockholm, Sweden, 1.5 T/7 MV) were determined for future use in reference dosimetry. Simulated values for thimble-type chambers are in good agreement with experiments as well as with the results of previous publications. After further experimental validation, the results can be considered for definition of standard protocols for purposes of reference dosimetry in MRgRT.

The Outdoor Atmospheric Simulation Chamber of Orleans-France (HELIOS)

NASA Astrophysics Data System (ADS)

Mellouki, A.; Véronique, D.; Grosselin, B.; Peyroux, F.; Benoit, R.; Ren, Y.; Idir, M.

2016-12-01

Atmospheric simulation chambers are among the most advanced tools for investigating the atmospheric processes to derive physico-chemical parameters which are required for air quality and climate models. Recently, the ICARE-CNRS at Orléans (France) has set up a new large outdoor simulation chamber, HELIOS. HELIOS is one of the most advanced simulation chambers in Europe. It is one of the largest outdoor chambers and is especially suited to processes studies performed under realistic atmospheric conditions. HELIOS is a large hemispherical outdoor simulation chamber (volume of 90 m3) positioned on the top of ICARE-CNRS building at Orléans (47°50'18.39N; 1°56'40.03E). The chamber is made of FEP film ensuring more than 90 % solar light transmission. The chamber is protected against severe meteorological conditions by a moveable "box" which contains a series of Xenon lamps enabling to conduct experiments using artificial light. This special design makes HELIOS a unique platform where experiments can be made using both types of irradiations. HELIOS is dedicated mainly to the investigation of the chemical processes under different conditions (sunlight, artificial light and dark). The platform allows conducting the same type of experiments under both natural and artificial light irradiation. The available large range of complementary and highly sensitive instruments allows investigating the radical chemistry, gas phase processes and aerosol formation under realistic conditions. The characteristics of HELIOS will be presented as well as the first series of experimental results obtained so far.

A facility for long-term Mars simulation experiments: the Mars Environmental Simulation Chamber (MESCH).

PubMed

Jensen, Lars Liengaard; Merrison, Jonathan; Hansen, Aviaja Anna; Mikkelsen, Karina Aarup; Kristoffersen, Tommy; Nørnberg, Per; Lomstein, Bente Aagaard; Finster, Kai

2008-06-01

We describe the design, construction, and pilot operation of a Mars simulation facility comprised of a cryogenic environmental chamber, an atmospheric gas analyzer, and a xenon/mercury discharge source for UV generation. The Mars Environmental Simulation Chamber (MESCH) consists of a double-walled cylindrical chamber. The double wall provides a cooling mantle through which liquid N(2) can be circulated. A load-lock system that consists of a small pressure-exchange chamber, which can be evacuated, allows for the exchange of samples without changing the chamber environment. Fitted within the MESCH is a carousel, which holds up to 10 steel sample tubes. Rotation of the carousel is controlled by an external motor. Each sample in the carousel can be placed at any desired position. Environmental data, such as temperature, pressure, and UV exposure time, are computer logged and used in automated feedback mechanisms, enabling a wide variety of experiments that include time series. Tests of the simulation facility have successfully demonstrated its ability to produce temperature cycles and maintain low temperature (down to -140 degrees C), low atmospheric pressure (5-10 mbar), and a gas composition like that of Mars during long-term experiments.

A Facility for Long-Term Mars Simulation Experiments: The Mars Environmental Simulation Chamber (MESCH)

NASA Astrophysics Data System (ADS)

Jensen, Lars Liengaard; Merrison, Jonathan; Hansen, Aviaja Anna; Mikkelsen, Karina Aarup; Kristoffersen, Tommy; Nørnberg, Per; Lomstein, Bente Aagaard; Finster, Kai

2008-06-01

We describe the design, construction, and pilot operation of a Mars simulation facility comprised of a cryogenic environmental chamber, an atmospheric gas analyzer, and a xenon/mercury discharge source for UV generation. The Mars Environmental Simulation Chamber (MESCH) consists of a double-walled cylindrical chamber. The double wall provides a cooling mantle through which liquid N2 can be circulated. A load-lock system that consists of a small pressure-exchange chamber, which can be evacuated, allows for the exchange of samples without changing the chamber environment. Fitted within the MESCH is a carousel, which holds up to 10 steel sample tubes. Rotation of the carousel is controlled by an external motor. Each sample in the carousel can be placed at any desired position. Environmental data, such as temperature, pressure, and UV exposure time, are computer logged and used in automated feedback mechanisms, enabling a wide variety of experiments that include time series. Tests of the simulation facility have successfully demonstrated its ability to produce temperature cycles and maintain low temperature (down to -140°C), low atmospheric pressure (5 10 mbar), and a gas composition like that of Mars during long-term experiments.

WE-G-BRA-06: Calibrating an Ionisation Chamber: Gaining Experience Using a Dosimetry 'flight Simulator'.

PubMed

Beavis, A; Saunderson, J; Ward, J

2012-06-01

Recently there has been great interest in the use of simulation training, with the view to enhance safety within radiotherapy practice. We have developed a Virtual Environment for Radiotherapy Training (VERT) which facilitates this, including the simulation of a number of 'Physics practices'. One such process is the calibration of an ionisation chamber for use in Linac photon beams. The VERT system was used to provide a life sized 3D virtual environment within which we were able to simulate the calibration of a departmental chamber for 6MV and 15 MV beams following the UK 1990 Code of Practice. The characteristics of the beams are fixed parameters in the simulation, whereas default (Absorbed dose to water) correction factors of the chambers are configurable thereby dictating their response in the virtual x-ray beam. When the simulation is started, a random, realistic temperature and pressure is assigned to the bunker. Measurement and chamber positional errors are assigned to the chambers. A virtual water phantom was placed on the Linac couch and irradiated through the side using a 10 × 10 field. With a chamber at the appropriate depths and irradiated iso-centrically, the Quality Indices (QI) of the beams were obtained. The two chambers were 'inter-compared', allowing the departmental chamber calibration factor to be calculated from that of the reference chamber. For the virtual 6/15 MV beams, the QI were found to be 0.668/ 0.761 and the inter-comparison ratios 0.4408/ 0.4402 respectively. The departmental chamber calibration factors were calculated; applying these and appropriate environmental corrections allowed the output of the Linac to be confirmed. We have shown how a virtual training environment can be used to demonstrate practical processes and reinforce learning. The UK CoP was used here, however any relevant protocol could be demonstrated. Two of the authors (Beavis and Ward) are Founders of Vertual Ltd, a spin-out company created to commercialise the research presented in this abstract. © 2012 American Association of Physicists in Medicine.

Monte Carlo calculation of energy deposition in ionization chambers for tritium measurements

NASA Astrophysics Data System (ADS)

Zhilin, Chen; Shuming, Peng; Dan, Meng; Yuehong, He; Heyi, Wang

2014-10-01

Energy deposition in ionization chambers for tritium measurements has been theoretically studied using Monte Carlo code MCNP 5. The influence of many factors, including carrier gas, chamber size, wall materials and gas pressure, has been evaluated in the simulations. It is found that β rays emitted by tritium deposit much more energy into chambers flowing through with argon than with deuterium in them, as much as 2.7 times higher at pressure 100 Pa. As chamber size gets smaller, energy deposition decreases sharply. For an ionization chamber of 1 mL, β rays deposit less than 1% of their energy at pressure 100 Pa and only 84% even if gas pressure is as high as 100 kPa. It also indicates that gold plated ionization chamber results in the highest deposition ratio while aluminum one leads to the lowest. In addition, simulations were validated by comparison with experimental data. Results show that simulations agree well with experimental data.

Superconducting-Magnet-Based Faraday Rotation Spectrometer for Real Time in Situ Measurement of OH Radicals at 106 Molecule/cm3 Level in an Atmospheric Simulation Chamber.

PubMed

Zhao, Weixiong; Fang, Bo; Lin, Xiaoxiao; Gai, Yanbo; Zhang, Weijun; Chen, Wenge; Chen, Zhiyou; Zhang, Haifeng; Chen, Weidong

2018-03-20

Atmospheric simulation chambers play vital roles in the validation of chemical mechanisms and act as a bridge between field measurements and modeling. Chambers operating at atmospheric levels of OH radicals (10 6 -10 7 molecule/cm 3 ) can significantly enhance the possibility for investigating the discrepancies between the observation and model predications. However, few chambers can directly detect chamber OH radicals at ambient levels. In this paper, we report on the first combination of a superconducting magnet with midinfrared Faraday rotation spectroscopy (FRS) for real time in situ measurement of the OH concentration in an atmospheric simulation chamber. With the use of a multipass enhanced FRS, a detection limit of 3.2 × 10 6 OH/cm 3 (2σ, 4 s) was achieved with an absorption path length of 108 m. The developed FRS system provided a unique, self-calibrated analytical instrument for in situ direct measurement of chamber OH concentration.

Crosstalk between immune cells and mesenchymal stromal cells in a 3D bioreactor system.

PubMed

Seifert, Martina; Lubitz, Annika; Trommer, Jeanne; Könnig, Darja; Korus, Gabriela; Marx, Uwe; Volk, Hans-Dieter; Duda, Georg; Kasper, Grit; Lehmann, Kerstin; Stolk, Meaghan; Giese, Christoph

2012-11-01

Mesenchymal stromal cells (MSC), known for their high immune modulatory capacity are promising tools for several cell-based therapies. To better mimic the in vivo situation of MSC interactions with immune cells, we applied an artificial lymph node (ALN)-bioreactor culture system combining a miniaturized perfusion bioreactor with a 3D matrix-based cell culture of immune competent cells forming micro-organoids. Rat lymph node cells and allogeneic bone marrow-derived MSCs were seeded in a 20:1 ratio within the agarose matrix of the ALN-reactor. Lymphocytes were pre-incubated with Concanavalin A (ConA) and then co-cultured with MSC in the matrix with additional ConA in the perfusing medium. Live/dead staining showed survival of the co-cultures during the 8-day ALN-reactor run. Paraffin sections of bioreactor matrices were analyzed by proliferating cell nuclear antigen (PCNA)-specific stai-ning to determine MSC proliferation. Immune modulatory capacity was defined by daily analysis of cytokine secretion profiles (TNFa, IFNy, IL-1a, IL-1ß, IL-2, IL-4, IL-6, IL-10, IL-12p40/p70, GM-CSF). Cytokine peak secretion at day 2 was significantly inhibited by MSCs for TNFa (96.8 ± 4.8%) and IFNy (88.7 ± 12.0%) in 3D co-cultures. In contrast, other cytokines (IL-1, IL-6, IL-12) were induced. Furthermore, we detected a significantly higher (58.8%) fraction of proliferating MSCs in the presence of immune cells compared to control bioreactors loaded with MSCs only. In the future, this system might be an excellent tool to investigate the mechanisms of MSC-mediated immune modulation during simulated in vivo conditions.

The EMEP MSC-W chemical transport model - technical description

NASA Astrophysics Data System (ADS)

Simpson, D.; Benedictow, A.; Berge, H.; Bergström, R.; Emberson, L. D.; Fagerli, H.; Flechard, C. R.; Hayman, G. D.; Gauss, M.; Jonson, J. E.; Jenkin, M. E.; Nyíri, A.; Richter, C.; Semeena, V. S.; Tsyro, S.; Tuovinen, J.-P.; Valdebenito, Á.; Wind, P.

2012-08-01

The Meteorological Synthesizing Centre-West (MSC-W) of the European Monitoring and Evaluation Programme (EMEP) has been performing model calculations in support of the Convention on Long Range Transboundary Air Pollution (CLRTAP) for more than 30 years. The EMEP MSC-W chemical transport model is still one of the key tools within European air pollution policy assessments. Traditionally, the model has covered all of Europe with a resolution of about 50 km × 50 km, and extending vertically from ground level to the tropopause (100 hPa). The model has changed extensively over the last ten years, however, with flexible processing of chemical schemes, meteorological inputs, and with nesting capability: the code is now applied on scales ranging from local (ca. 5 km grid size) to global (with 1 degree resolution). The model is used to simulate photo-oxidants and both inorganic and organic aerosols. In 2008 the EMEP model was released for the first time as public domain code, along with all required input data for model runs for one year. The second release of the EMEP MSC-W model became available in mid 2011, and a new release is targeted for summer 2012. This publication is intended to document this third release of the EMEP MSC-W model. The model formulations are given, along with details of input data-sets which are used, and a brief background on some of the choices made in the formulation is presented. The model code itself is available at www.emep.int, along with the data required to run for a full year over Europe.

The EMEP MSC-W chemical transport model - Part 1: Model description

NASA Astrophysics Data System (ADS)

Simpson, D.; Benedictow, A.; Berge, H.; Bergström, R.; Emberson, L. D.; Fagerli, H.; Hayman, G. D.; Gauss, M.; Jonson, J. E.; Jenkin, M. E.; Nyíri, A.; Richter, C.; Semeena, V. S.; Tsyro, S.; Tuovinen, J.-P.; Valdebenito, Á.; Wind, P.

2012-02-01

The Meteorological Synthesizing Centre-West (MSC-W) of the European Monitoring and Evaluation Programme (EMEP) has been performing model calculations in support of the Convention on Long Range Transboundary Air Pollution (CLRTAP) for more than 30 yr. The EMEP MSC-W chemical transport model is still one of the key tools within European air pollution policy assessments. Traditionally, the EMEP model has covered all of Europe with a resolution of about 50 × 50 km2, and extending vertically from ground level to the tropopause (100 hPa). The model has undergone substantial development in recent years, and is now applied on scales ranging from local (ca. 5 km grid size) to global (with 1 degree resolution). The model is used to simulate photo-oxidants and both inorganic and organic aerosols. In 2008 the EMEP model was released for the first time as public domain code, along with all required input data for model runs for one year. Since then, many changes have been made to the model physics, and input data. The second release of the EMEP MSC-W model became available in mid 2011, and a new release is targeted for early 2012. This publication is intended to document this third release of the EMEP MSC-W model. The model formulations are given, along with details of input data-sets which are used, and brief background on some of the choices made in the formulation are presented. The model code itself is available at www.emep.int, along with the data required to run for a full year over Europe.

The role of oxygen as a regulator of stem cell fate during fracture repair in TSP2-null mice.

PubMed

Burke, Darren; Dishowitz, Michael; Sweetwyne, Mariya; Miedel, Emily; Hankenson, Kurt D; Kelly, Daniel J

2013-10-01

It is often difficult to decouple the relative importance of different factors in regulating MSC differentiation. Genetically modified mice provide model systems whereby some variables can be manipulated while others are kept constant. Fracture repair in thrombospondin-2 (TSP2)-null mice is characterized by reduced endochondral ossification and enhanced intramembranous bone formation. The proposed mechanism for this shift in MSC fate is that increased vascular density and hence oxygen availability in TSP2-null mice regulates differentiation. However, TSP2 is multifunctional and regulates other aspects of the regenerative cascade, such as MSC proliferation. The objective of this study is to use a previously developed computational model of tissue differentiation, in which substrate stiffness and oxygen tension regulate stem cell differentiation, to simulate potential mechanisms which may drive alterations in MSC fate in TSP2-null mice. Four models (increased cell proliferation, increased numbers of MSCs in the marrow decreased cellular oxygen consumption, and an initially stiffer callus) were not predictive of experimental observations in TSP2-null mice. In contrast, increasing the rate of angiogenic progression led to a prediction of greater intramembranous ossification, diminished endochondral ossification, and a reduced region of hypoxia in the fracture callus similar to that quantified experimentally by the immunohistochemical detection of pimonidazole adducts that develop with hypoxia. This study therefore provides further support for the hypothesis that oxygen availability during early fracture healing is a key regulator of MSC bipotential differentiation, and furthermore, it highlights the advantages of integrating computational models with genetically modified mouse studies for further elucidating mechanisms regulating stem cell fate. Copyright © 2013 Orthopaedic Research Society.

Mutagenicity in Salmonella of a Simulated Urban-Smog Atmosphere Generated Using a Mobile Reaction Chamber

EPA Science Inventory

The EPA Mobile Reaction Chamber (MRC) is a 24-foot trailer containing a 14.3-m3 Teflon lined photochemical chamber used to generate simulated urban atmospheres. Photochemistry in the MRC is catalyzed by 120 fluorescent bulbs evenly mixed with black light bulbs and UV bulbs (300 &...

A Bioactive Hydrogel and 3D Printed Polycaprolactone System for Bone Tissue Engineering.

PubMed

Hernandez, Ivan; Kumar, Alok; Joddar, Binata

2017-09-01

In this study, a hybrid system consisting of 3D printed polycaprolactone (PCL) filled with hydrogel was developed as an application for reconstruction of long bone defects, which are innately difficult to repair due to large missing segments of bone. A 3D printed gyroid scaffold of PCL allowed a larger amount of hydrogel to be loaded within the scaffolds as compared to 3D printed mesh and honeycomb scaffolds of similar volumes and strut thicknesses. The hydrogel was a mixture of alginate, gelatin, and nano-hydroxyapatite, infiltrated with human mesenchymal stem cells (hMSC) to enhance the osteoconductivity and biocompatibility of the system. Adhesion and viability of hMSC in the PCL/hydrogel system confirmed its cytocompatibility. Biomineralization tests in simulated body fluid (SBF) showed the nucleation and growth of apatite crystals, which confirmed the bioactivity of the PCL/hydrogel system. Moreover, dissolution studies, in SBF revealed a sustained dissolution of the hydrogel with time. Overall, the present study provides a new approach in bone tissue engineering to repair bone defects with a bioactive hybrid system consisting of a polymeric scaffold, hydrogel, and hMSC.

An Integrated Solution for Performing Thermo-fluid Conjugate Analysis

NASA Technical Reports Server (NTRS)

Kornberg, Oren

2009-01-01

A method has been developed which integrates a fluid flow analyzer and a thermal analyzer to produce both steady state and transient results of 1-D, 2-D, and 3-D analysis models. The Generalized Fluid System Simulation Program (GFSSP) is a one dimensional, general purpose fluid analysis code which computes pressures and flow distributions in complex fluid networks. The MSC Systems Improved Numerical Differencing Analyzer (MSC.SINDA) is a one dimensional general purpose thermal analyzer that solves network representations of thermal systems. Both GFSSP and MSC.SINDA have graphical user interfaces which are used to build the respective model and prepare it for analysis. The SINDA/GFSSP Conjugate Integrator (SGCI) is a formbase graphical integration program used to set input parameters for the conjugate analyses and run the models. The contents of this paper describes SGCI and its thermo-fluids conjugate analysis techniques and capabilities by presenting results from some example models including the cryogenic chill down of a copper pipe, a bar between two walls in a fluid stream, and a solid plate creating a phase change in a flowing fluid.

Genetically-modified pig mesenchymal stromal cells: xenoantigenicity and effect on human T-cell xenoresponses.

PubMed

Ezzelarab, Mohamed; Ezzelarab, Corin; Wilhite, Tyler; Kumar, Goutham; Hara, Hidetaka; Ayares, David; Cooper, David K C

2011-01-01

Mesenchymal stromal cells (MSC) are being investigated as immunomodulatory therapy in the field of transplantation, particularly islet transplantation. While MSC can regenerate across species barriers, the immunoregulatory influence of genetically modified pig MSC (pMSC) on the human and non-human primate T-cell responses has not been studied. Mesenchymal stromal cells from wild-type (WT), α1,3-galactosyltransferase gene knockout (GTKO) and GTKO pigs transgenic for the human complement-regulatory protein CD46 (GTKO/CD46) were isolated and tested for differentiation. Antibody binding and T-cell responses to WT and GTKO pMSC in comparison with GTKO pig aortic endothelial cells (pAEC) were investigated. The expression of swine leukocyte antigen (SLA) class II (SLA II) was tested. Costimulatory molecules CD80 and CD86 mRNA levels were measured. Human T-cell proliferation and the production of pro-inflammatory cytokines in response to GTKO and GTKO/CD46 pMSC in comparison with human MSC (hMSC) were evaluated. α1,3-galactosyltransferase gene knockout and GTKO/CD46 pMSC isolation and differentiation were achieved in vitro. Binding of human antibodies and T-cell responses were lower to GTKO than those to WT pMSC. Human and baboon (naïve and sensitized) antibody binding were significantly lower to GTKO pMSC than to GTKO pAEC. Before activation, <1% of GTKO pMSC expressed SLA II, compared with 2.5% of GTKO pAEC. After pig interferon-gamma (pIFN-γ) activation, 99% of GTKO pAEC upregulated SLA II expression, compared with 49% of GTKO pMSC. Only 3% of GTKO pMSC expressed CD80 compared with 80% of GTKO pAEC without activation. After pIFN-γ activation, GTKO pAEC upregulated CD86 mRNA level stronger than GTKO pMSC. The human CD4(+) T-cell response to GTKO pMSC was significantly weaker than that to GTKO pAEC, even after pIFN-γ activation. More than 99% of GTKO/CD46 pMSC expressed hCD46. Human peripheral blood mononuclear cells and CD4(+) T-cell responses to GTKO and GTKO/CD46 pMSC were comparable with those to hMSC, and all were significantly lower than to GTKO pAEC. GTKO/CD46 pMSC downregulated human T-cell proliferation as efficiently as hMSC. The level of proinflammatory cytokines IL-2, IFN-γ, TNF-α, and sCD40L correlated with the downregulation of T-cell proliferation by all types of MSC. Genetically modified pMSC is significantly less immunogenic than WT pMSC. GTKO/CD46 pMSC downregulates the human T-cell responses to pig antigens as efficiently as human MSC, which can be advantageous for therapeutic cell xenotransplantation. © 2011 John Wiley & Sons A/S.

Infusion of Trx-1-Overexpressing hucMSC Prolongs the Survival of Acutely Irradiated NOD/SCID Mice by Decreasing Excessive Inflammatory Injury

PubMed Central

Wang, Jun; Tang, YongYong; Liu, Hao; Zhang, Bin; Chen, Hu

2013-01-01

A protective reagent for ARI should have the ability to repair injured tissue caused by radiation and prevent continuous damage from secondary risk factors. Trx-1 was explored as a candidate therapy for ARI, as it scavenges reactive oxygen species, regulates cell growth and differentiation, participates in immune reactions, and inhibits apoptosis by acting inside and/or outside cells. Trx-1 can also decrease excessive inflammation in ARI by regulating the creation of inflamed media, by inhibiting the activation of complement, and by reducing the chemotaxis, adhesion, and migration of inflammatory cells. As effectively and stably expressing exogenous genes in the long term and regulating immune inflammation and tissue repair, MSC are a good choice for Trx-1 gene therapy. In this study, Trx-1-overexpressing hucMSC-Trx-1 were obtained by adenoviral vector-mediated infection. We first measured the redox capacity of hucMSC-Trx-1 with an antioxidant capacity (T-AOC) assay, a hydrogen peroxide (H2O2) content determination assay in vivo, a H2O2-induced oxidation hemolysis assay, and a lipid peroxidation assay in vitro. Then, we measured survival time, the protection of the hematopoietic system, and the regulation of inflammation in important organs in three treatment groups of NOD/SCID mice (treated with hucMSC-Trx-1, with hucMSC, and with saline) that were exposed to 4.5 Gy 60Co-γ-ray radiation. The hucMSC-Trx-1 group achieved superior antioxidation results, protecting bone marrow hematopoietic stem cells (Lin−CD117+: hucMSC-Trx-1 vs. hucMSC, P<0.05; hucMSC-Trx-1 vs. NS, P<0.01), promoting the formation of red blood cells and hemoglobin (hucMSC-Trx-1 vs. hucMSC or NS, P<0.05), reducing inflammation and damage in important organs (Bone marrow and lung: hucMSC-Trx-1 vs. NS, P<0.01; hucMSC-Trx-1 vs. hucMSC, P<0.05. Liver and intestine: hucMSC-Trx-1 vs. NS, P<0.05; hucMSC-Trx-1 vs. hucMSC, P<0.05), and prolonging survival (hucMSC-Trx-1 vs. hucMSC or NS, P<0.01). Therefore, hucMSC-Trx-1 combines the merits of gene and cell therapy as a multifunctional radioprotector for ARI. PMID:24223778

Infusion of Trx-1-overexpressing hucMSC prolongs the survival of acutely irradiated NOD/SCID mice by decreasing excessive inflammatory injury.

PubMed

Hu, JiangWei; Yang, ZaiLiang; Wang, Jun; Tang, YongYong; Liu, Hao; Zhang, Bin; Chen, Hu

2013-01-01

A protective reagent for ARI should have the ability to repair injured tissue caused by radiation and prevent continuous damage from secondary risk factors. Trx-1 was explored as a candidate therapy for ARI, as it scavenges reactive oxygen species, regulates cell growth and differentiation, participates in immune reactions, and inhibits apoptosis by acting inside and/or outside cells. Trx-1 can also decrease excessive inflammation in ARI by regulating the creation of inflamed media, by inhibiting the activation of complement, and by reducing the chemotaxis, adhesion, and migration of inflammatory cells. As effectively and stably expressing exogenous genes in the long term and regulating immune inflammation and tissue repair, MSC are a good choice for Trx-1 gene therapy. In this study, Trx-1-overexpressing hucMSC-Trx-1 were obtained by adenoviral vector-mediated infection. We first measured the redox capacity of hucMSC-Trx-1 with an antioxidant capacity (T-AOC) assay, a hydrogen peroxide (H2O2) content determination assay in vivo, a H2O2-induced oxidation hemolysis assay, and a lipid peroxidation assay in vitro. Then, we measured survival time, the protection of the hematopoietic system, and the regulation of inflammation in important organs in three treatment groups of NOD/SCID mice (treated with hucMSC-Trx-1, with hucMSC, and with saline) that were exposed to 4.5 Gy (60)Co-γ-ray radiation. The hucMSC-Trx-1 group achieved superior antioxidation results, protecting bone marrow hematopoietic stem cells (Lin(-)CD117(+): hucMSC-Trx-1 vs. hucMSC, P<0.05; hucMSC-Trx-1 vs. NS, P<0.01), promoting the formation of red blood cells and hemoglobin (hucMSC-Trx-1 vs. hucMSC or NS, P<0.05), reducing inflammation and damage in important organs (Bone marrow and lung: hucMSC-Trx-1 vs. NS, P<0.01; hucMSC-Trx-1 vs. hucMSC, P<0.05. Liver and intestine: hucMSC-Trx-1 vs. NS, P<0.05; hucMSC-Trx-1 vs. hucMSC, P<0.05), and prolonging survival (hucMSC-Trx-1 vs. hucMSC or NS, P<0.01). Therefore, hucMSC-Trx-1 combines the merits of gene and cell therapy as a multifunctional radioprotector for ARI.

Cytokine treatment optimises the immunotherapeutic effects of umbilical cord-derived MSC for treatment of inflammatory liver disease.

PubMed

de Witte, Samantha F H; Merino, Ana M; Franquesa, Marcella; Strini, Tanja; van Zoggel, Johanna A A; Korevaar, Sander S; Luk, Franka; Gargesha, Madhu; O'Flynn, Lisa; Roy, Debashish; Elliman, Steve J; Newsome, Philip N; Baan, Carla C; Hoogduijn, Martin J

2017-06-08

Mesenchymal stromal cells (MSC) possess immunomodulatory properties and low immunogenicity, both crucial properties for their development into an effective cellular immunotherapy. They have shown benefit in clinical trials targeting liver diseases; however the efficacy of MSC therapy will benefit from improvement of the immunomodulatory and immunogenic properties of MSC. MSC derived from human umbilical cords (ucMSC) were treated for 3 days in vitro with various inflammatory factors, interleukins, vitamins and serum deprivation. Their immunogenicity and immunomodulatory capacity were examined by gene-expression analysis, surface-marker expressions, IDO activity, PGE 2 secretion and inhibition of T cell proliferation and IFNγ production. Furthermore, their activation of NK cell cytotoxicity was investigated via CD107a expression on NK cells. The immunomodulatory capacity, biodistribution and survival of pre-treated ucMSC were investigated in a CCl 4 -induced liver disease mouse model. In addition, capacity of pre-treated MSC to ameliorate liver inflammation was examined in an ex vivo liver inflammation co-culture model. IFN-γ and a multiple cytokine cocktail (MC) consisting of IFN-γ, TGFβ and retinoic acid upregulated the expression of immunomodulatory factor PD-L1 and IDO activity. Subsequently, both treatments enhanced the capacity of ucMSC to inhibit CD4 and CD8 T cell proliferation and IFN-γ production. The susceptibility of ucMSC for NK cell lysis was decreased by IFN-β, TGFβ and MC treatment. In vivo, no immunomodulation was observed by the ucMSC. Four hours after intravenous infusion in mice with CCl 4 -induced inflammatory liver injury, the majority of ucMSC were trapped in the lungs. Rapid clearance of ucMSC(VitB 6 ), ucMSC(Starv + VitB 6 ) and ucMSC(MC) and altered bio-distribution of ucMSC(TGFβ) compared to untreated ucMSC was observed. In the ex vivo co-culture system with inflammatory liver slices ucMSC(MC) showed significantly enhanced modulatory capacity compared to untreated ucMSC. The present study demonstrates the responsiveness of ucMSC to in vitro optimisation treatment. The observed improvements in immunomodulatory capacity as well as immunogenicity after MC treatment may improve the efficacy of ucMSC as immunotherapy targeted towards liver inflammation.

Activity of a C-terminal plant homeodomain (PHD) of Msc1 is essential for function.

PubMed

Qiu, Xinxing; Dul, Barbara E; Walworth, Nancy C

2010-11-19

Msc1, a member of the Jarid1 family of putative histone demethylases, is required for chromosome stability in fission yeast. Msc1 associates with the Swr1 complex that facilitates deposition of histone H2A.Z into chromatin. To assess the function of Msc1 in the Swr1 complex, domains of Msc1 necessary for interaction with Swr1 were identified. The C-terminal plant homeodomain (PHD) 2 and PHD3 of Msc1 are sufficient to confer association with Swr1 and allow Msc1 to function in the context of kinetochore mutants. On the other hand, a mutant with a single amino acid substitution in PHD2 within the full-length Msc1 protein retains the ability to bind to Swr1 but eliminates the function of Msc1 in combination with kinetochore mutants. Thus, Swr1 association is critical but not sufficient for Msc1 function. An activity of Msc1 that depends on the cysteine residue within PHD2 of Msc1 is likewise critical for function. On the basis of our observation that the PHDs of Msc1 act as E3 ubiquitin ligases and that mutations of cysteine residues within those domains abolish ligase activity, we speculate that the ability of Msc1 to facilitate ubiquitin transfer is critical for the function it mediates through its association with Swr1.

Activity of a C-terminal Plant Homeodomain (PHD) of Msc1 Is Essential for Function*

PubMed Central

Qiu, Xinxing; Dul, Barbara E.; Walworth, Nancy C.

2010-01-01

Msc1, a member of the Jarid1 family of putative histone demethylases, is required for chromosome stability in fission yeast. Msc1 associates with the Swr1 complex that facilitates deposition of histone H2A.Z into chromatin. To assess the function of Msc1 in the Swr1 complex, domains of Msc1 necessary for interaction with Swr1 were identified. The C-terminal plant homeodomain (PHD) 2 and PHD3 of Msc1 are sufficient to confer association with Swr1 and allow Msc1 to function in the context of kinetochore mutants. On the other hand, a mutant with a single amino acid substitution in PHD2 within the full-length Msc1 protein retains the ability to bind to Swr1 but eliminates the function of Msc1 in combination with kinetochore mutants. Thus, Swr1 association is critical but not sufficient for Msc1 function. An activity of Msc1 that depends on the cysteine residue within PHD2 of Msc1 is likewise critical for function. On the basis of our observation that the PHDs of Msc1 act as E3 ubiquitin ligases and that mutations of cysteine residues within those domains abolish ligase activity, we speculate that the ability of Msc1 to facilitate ubiquitin transfer is critical for the function it mediates through its association with Swr1. PMID:20858896

Antimicrobial peptides secreted by equine mesenchymal stromal cells inhibit the growth of bacteria commonly found in skin wounds.

PubMed

Harman, Rebecca M; Yang, Steven; He, Megan K; Van de Walle, Gerlinde R

2017-07-04

The prevalence of chronic skin wounds in humans is high, and treatment is often complicated by the presence of pathogenic bacteria. Therefore, safe and innovative treatments to reduce the bacterial load in cutaneous wounds are needed. Mesenchymal stromal cells (MSC) are known to provide paracrine signals that act on resident skin cells to promote wound healing, but their potential antibacterial activities are not well described. The present study was designed to examine the antibacterial properties of MSC from horses, as this animal model offers a readily translatable model for MSC therapies in humans. Specifically, we aimed to (i) evaluate the in vitro effects of equine MSC on the growth of representative gram-negative and gram-positive bacterial species commonly found in skin wounds and (ii) define the mechanisms by which MSC inhibit bacterial growth. MSC were isolated from the peripheral blood of healthy horses. Gram-negative E. coli and gram-positive S. aureus were cultured in the presence of MSC and MSC conditioned medium (CM), containing all factors secreted by MSC. Bacterial growth was measured by plating bacteria and counting viable colonies or by reading the absorbance of bacterial cultures. Bacterial membrane damage was detected by incorporation of N-phenyl-1-naphthylamine (NPN). Antimicrobial peptide (AMP) gene and protein expression by equine MSC were determined by RT-PCR and Western blot analysis, respectively. Blocking of AMP activity of MSC CM was achieved using AMP-specific antibodies. We found that equine MSC and MSC CM inhibit the growth of E. coli and S. aureus, and that MSC CM depolarizes the cell membranes of these bacteria. In addition, we found that equine MSC CM contains AMPs, and blocking these AMPs with antibodies reduces the effects of MSC CM on bacteria. Our results demonstrate that equine MSC inhibit bacterial growth and secrete factors that compromise the membrane integrity of bacteria commonly found in skin wounds. We also identified four specific AMPs produced by equine MSC. The secretion of AMPs may contribute to the value of MSC as a therapy for cutaneous wounds in both horses and humans.

Inhibition of AQP1 Hampers Osteosarcoma and Hepatocellular Carcinoma Progression Mediated by Bone Marrow-Derived Mesenchymal Stem Cells.

PubMed

Pelagalli, Alessandra; Nardelli, Anna; Fontanella, Raffaela; Zannetti, Antonella

2016-07-11

The complex cross-talk between tumor cells and their surrounding stromal environment plays a key role in the pathogenesis of cancer. Among several cell types that constitute the tumor stroma, bone marrow-derived mesenchymal stem cells (BM-MSCs) selectively migrate toward the tumor microenvironment and contribute to the active formation of tumor-associated stroma. Therefore, here we elucidate the involvement of BM-MSCs to promote osteosarcoma (OS) and hepatocellular carcinoma (HCC) cells migration and invasion and deepening the role of specific pathways. We analyzed the function of aquaporin 1 (AQP1), a water channel known to promote metastasis and neoangiogenes. AQP1 protein levels were analyzed in OS (U2OS) and HCC (SNU-398) cells exposed to conditioned medium from BM-MSCs. Tumor cell migration and invasion in response to BM-MSC conditioned medium were evaluated through a wound healing assay and Boyden chamber, respectively. The results showed that the AQP1 level was increased in both tumor cell lines after treatment with BM-MSC conditioned medium. Moreover, BM-MSCs-mediated tumor cell migration and invasion were hampered after treatment with AQP1 inhibitor. These data suggest that the recruitment of human BM-MSCs into the tumor microenvironment might cause OS and HCC cell migration and invasion through involvement of AQP1.

Effects of Freeze-Thawing and Intravenous Infusion on Mesenchymal Stromal Cell Gene Expression.

PubMed

Hoogduijn, Martin J; de Witte, Samantha F H; Luk, Franka; van den Hout-van Vroonhoven, Mirjam C G N; Ignatowicz, Lech; Catar, Rusan; Strini, Tanja; Korevaar, Sander S; van IJcken, Wilfred F J; Betjes, Michiel G H; Franquesa, Marcella; Moll, Guido; Baan, Carla C

2016-04-15

Mesenchymal stromal cells (MSC) are increasingly used as an investigative therapeutic product for immune disorders and degenerative disease. Typically, MSC are isolated from human tissue, expanded in culture, and cryopreserved until usage. The safety and efficacy of MSC therapy will depend on the phenotypical and functional characteristics of MSC. The freeze-thawing procedure may change these characteristics. Furthermore, the cells encounter a microenvironment after administration that may impact their properties. It has been demonstrated that the majority of MSC localize to the lungs after intravenous infusion, making this the site to study the effects of the in vivo milieu on administered MSC. In this study, we investigated the effect of freeze-thawing and the mouse lung microenvironment on human adipose tissue-derived MSC. There were effects of freeze-thawing on the whole genome expression profile of MSC, although the effects did not exceed interdonor differences. There were no major changes in the expression of hemostatic regulators on transcriptional level, but significantly increased expression of procoagulant tissue factor on the surface of thawed adipose MSC, correlating with increased procoagulant activity of thawed cells. Exposure for 2 h to the lung microenvironment had a major effect on MSC gene expression and affected several immunological pathways. This indicates that MSC undergo functional changes shortly after infusion and this may influence the efficacy of MSC to modulate inflammatory responses. The results of this study demonstrate that MSC rapidly alter in response to the local milieu and disease-specific conditions may shape MSC after administration.

The heterogeneity of human mesenchymal stem cell preparations--evidence from simultaneous analysis of proteomes and transcriptomes.

PubMed

Wagner, Wolfgang; Feldmann, Robert E; Seckinger, Anja; Maurer, Martin H; Wein, Frederik; Blake, Jonathon; Krause, Ulf; Kalenka, Armin; Bürgers, Heinrich F; Saffrich, Rainer; Wuchter, Patrick; Kuschinsky, Wolfgang; Ho, Anthony D

2006-04-01

Mesenchymal stem cells (MSC) raise high hopes in clinical applications. However, the lack of common standards and a precise definition of MSC preparations remains a major obstacle in research and application of MSC. Whereas surface antigen markers have failed to precisely define this population, a combination of proteomic data and microarray data provides a new dimension for the definition of MSC preparations. In our continuing effort to characterize MSC, we have analyzed the differential transcriptome and proteome expression profiles of MSC preparations isolated from human bone marrow under two different expansion media (BM-MSC-M1 and BM-MSC-M2). In proteomics, 136 protein spots were unambiguously identified by MALDI-TOF-MS and corresponding cDNA spots were selected on our "Human Transcriptome cDNA Microarray." Combination of datasets revealed a correlation in differential gene expression and protein expression of BM-MSC-M1 vs BM-MSC-M2. Genes involved in metabolism were more highly expressed in BM-MSC-M1, whereas genes involved in development, morphogenesis, extracellular matrix, and differentiation were more highly expressed in BM-MSC-M2. Interchanging culture conditions for 8 days revealed that differential expression was retained in several genes whereas it was altered in others. Our results have provided evidence that homogeneous BM-MSC preparations can reproducibly be isolated under standardized conditions, whereas culture conditions exert a prominent impact on transcriptome, proteome, and cellular organization of BM-MSC.

The influence of macrophages on mesenchymal stromal cell therapy: passive or aggressive agents?

PubMed Central

Carty, F.; English, K.

2017-01-01

Summary Mesenchymal stromal cells (MSC) have emerged as promising cell therapies for multiple conditions based on demonstrations of their potent immunomodulatory and regenerative capacities in models of inflammatory disease. Understanding the effects of MSC on T cells has dominated the majority of work carried out in this field to date; recently, however, a number of studies have shown that the therapeutic effect of MSC requires the presence of macrophages. It is timely to review the mechanisms and manner by which MSC modulate macrophage populations in order to design more effective MSC therapies and clinical studies. A complex cross‐talk exists through which MSC and macrophages communicate, a communication that is not controlled exclusively by MSC. Here, we examine the evidence that suggests that MSC not only respond to inflammatory macrophages and adjust their secretome accordingly, but also that macrophages respond to encounters with MSC, creating a feedback loop which contributes to the immune regulation observed following MSC therapy. Future studies examining the effects of MSC on macrophages should consider the antagonistic role that macrophages play in this exchange. PMID:28108980

Hypobaric chamber for the study of oral health problems in a simulated spacecraft environment

NASA Technical Reports Server (NTRS)

Brown, L. R.

1974-01-01

A hypobaric chamber was constructed to house two marmo-sets simultaneously in a space-simulated environment for periods of 14, 28 and 56 days which coincided with the anticipated Skylab missions. This report details the fabrication, operation, and performance of the chamber and very briefly reviews the scientific data from nine chamber trials involving 18 animals. The possible application of this model system to studies unrelated to oral health or space missions is discussed.

Chondrogenic induction of mesenchymal stromal/stem cells from Wharton's jelly embedded in alginate hydrogel and without added growth factor: an alternative stem cell source for cartilage tissue engineering.

PubMed

Reppel, Loïc; Schiavi, Jessica; Charif, Naceur; Leger, Léonore; Yu, Hao; Pinzano, Astrid; Henrionnet, Christel; Stoltz, Jean-François; Bensoussan, Danièle; Huselstein, Céline

2015-12-30

Due to their intrinsic properties, stem cells are promising tools for new developments in tissue engineering and particularly for cartilage tissue regeneration. Although mesenchymal stromal/stem cells from bone marrow (BM-MSC) have long been the most used stem cell source in cartilage tissue engineering, they have certain limits. Thanks to their properties such as low immunogenicity and particularly chondrogenic differentiation potential, mesenchymal stromal/stem cells from Wharton's jelly (WJ-MSC) promise to be an interesting source of MSC for cartilage tissue engineering. In this study, we propose to evaluate chondrogenic potential of WJ-MSC embedded in alginate/hyaluronic acid hydrogel over 28 days. Hydrogels were constructed by the original spraying method. Our main objective was to evaluate chondrogenic differentiation of WJ-MSC on three-dimensional scaffolds, without adding growth factors, at transcript and protein levels. We compared the results to those obtained from standard BM-MSC. After 3 days of culture, WJ-MSC seemed to be adapted to their new three-dimensional environment without any detectable damage. From day 14 and up to 28 days, the proportion of WJ-MSC CD73(+), CD90(+), CD105(+) and CD166(+) decreased significantly compared to monolayer marker expression. Moreover, WJ-MSC and BM-MSC showed different phenotype profiles. After 28 days of scaffold culture, our results showed strong upregulation of cartilage-specific transcript expression. WJ-MSC exhibited greater type II collagen synthesis than BM-MSC at both transcript and protein levels. Furthermore, our work highlighted a relevant result showing that WJ-MSC expressed Runx2 and type X collagen at lower levels than BM-MSC. Once seeded in the hydrogel scaffold, WJ-MSC and BM-MSC have different profiles of chondrogenic differentiation at both the phenotypic level and matrix synthesis. After 4 weeks, WJ-MSC, embedded in a three-dimensional environment, were able to adapt to their environment and express specific cartilage-related genes and matrix proteins. Today, WJ-MSC represent a real alternative source of stem cells for cartilage tissue engineering.

[Development of a microenvironment test chamber for airborne microbe research].

PubMed

Zhan, Ningbo; Chen, Feng; Du, Yaohua; Cheng, Zhi; Li, Chenyu; Wu, Jinlong; Wu, Taihu

2017-10-01

One of the most important environmental cleanliness indicators is airborne microbe. However, the particularity of clean operating environment and controlled experimental environment often leads to the limitation of the airborne microbe research. This paper designed and implemented a microenvironment test chamber for airborne microbe research in normal test conditions. Numerical simulation by Fluent showed that airborne microbes were evenly dispersed in the upper part of test chamber, and had a bottom-up concentration growth distribution. According to the simulation results, the verification experiment was carried out by selecting 5 sampling points in different space positions in the test chamber. Experimental results showed that average particle concentrations of all sampling points reached 10 7 counts/m 3 after 5 minutes' distributing of Staphylococcus aureus , and all sampling points showed the accordant mapping of concentration distribution. The concentration of airborne microbe in the upper chamber was slightly higher than that in the middle chamber, and that was also slightly higher than that in the bottom chamber. It is consistent with the results of numerical simulation, and it proves that the system can be well used for airborne microbe research.

Biologic and immunomodulatory properties of mesenchymal stromal cells derived from human pancreatic islets

PubMed Central

KIM, JAEHYUP; BREUNIG, MELISSA J.; ESCALANTE, LEAH E.; BHATIA, NEEHAR; DENU, RYAN A.; DOLLAR, BRIDGET A.; STEIN, ANDREW P.; HANSON, SUMMER E.; NADERI, NADIA; RADEK, JAMES; HAUGHY, DERMOT; BLOOM, DEBRA D.; ASSADI-PORTER, FARIBA M.; HEMATTI, PEIMAN

2012-01-01

Background aims Mesenchymal stromal cells (MSC) have now been shown to reside in numerous tissues throughout the body, including the pancreas. Ex vivo culture-expanded MSC derived from many tissues display important interactions with different types of immune cells in vitro and potentially play a significant role in tissue homeostasis in vivo. In this study, we investigated the biologic and immunomodulatory properties of human pancreatic islet-derived MSC. Methods We culture-expanded MSC from cadaveric human pancreatic islets and characterized them using flow cytometry, differentiation assays and nuclear magnetic resonance-based metabolomics. We also investigated the immunologic properties of pancreatic islet-derived MSC compared with bone marrow (BM) MSC. Results Pancreatic islet and BM-derived MSC expressed the same cell-surface markers by flow cytometry, and both could differentiate into bone, fat and cartilage. Metabolomics analysis of MSC from BM and pancreatic islets also showed a similar set of metabolic markers but quantitative polymerase chain reactions showed that pancreatic islet MSC expressed more interleukin(IL)-1b, IL-6, STAT3 and FGF9 compared with BM MSC, and less IL-10. However, similar to BM MSC, pancreatic islet MSC were able to suppress proliferation of allogeneic T lymphocytes stimulated with anti-CD3 and anti-CD28 antibodies. Conclusions Our in vitro analysis shows pancreatic islet-derived MSC have phenotypic, biologic and immunomodulatory characteristics similar, but not identical, to BM-derived MSC. We propose that pancreatic islet-derived MSC could potentially play an important role in improving the outcome of pancreatic islet transplantation by promoting engraftment and creating a favorable immune environment for long-term survival of islet allografts. PMID:22571381

Establishment and characterization of fetal and maternal mesenchymal stem/stromal cell lines from the human term placenta.

PubMed

Qin, Sharon Q; Kusuma, Gina D; Al-Sowayan, Batla; Pace, Rishika A; Isenmann, Sandra; Pertile, Mark D; Gronthos, Stan; Abumaree, Mohamed H; Brennecke, Shaun P; Kalionis, Bill

2016-03-01

Human placental mesenchymal stem/stromal cells (MSC) are an attractive source of MSC with great therapeutic potential. However, primary MSC are difficult to study in vitro due to their limited lifespan and patient-to-patient variation. Fetal and maternal MSC were prepared from cells of the chorionic and basal plates of the placenta, respectively. Fetal and maternal MSC were transduced with the human telomerase reverse transcriptase (hTERT). Conventional stem cell assays assessed the MSC characteristics of the cell lines. Functional assays for cell proliferation, cell migration and ability to form colonies in soft agar were used to assess the whether transduced cells retained properties of primary MSC. Fetal chorionic and maternal MSC were successfully transduced with hTERT to create the cell lines CMSC29 and DMSC23 respectively. The lifespans of CMSC29 and DMSC23 were extended in cell culture. Both cell lines retained important MSC characteristics including cell surface marker expression and multipotent differentiation potential. Neither of the cell lines was tumourigenic in vitro. Gene expression differences were observed between CMSC29 and DMSC23 cells and their corresponding parent, primary MSC. Both cell lines show similar migration potential to their corresponding primary, parent MSC. The data show that transduced MSC retained important functional properties of the primary MSC. There were gene expression and functional differences between cell lines CMSC29 and DMSC23 that reflect their different tissue microenvironments of the parent, primary MSC. CMSC29 and DMSC23 cell lines could be useful tools for optimisation and functional studies of MSC. Copyright © 2016 Elsevier Ltd. All rights reserved.

Impact of bacteria and bacterial components on osteogenic and adipogenic differentiation of adipose-derived mesenchymal stem cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fiedler, Tomas, E-mail: tomas.fiedler@med.uni-rostock.de; Salamon, Achim; Adam, Stefanie

Adult mesenchymal stem cells (MSC) are present in several tissues, e.g. bone marrow, heart muscle, brain and subcutaneous adipose tissue. In invasive infections MSC get in contact with bacteria and bacterial components. Not much is known about how bacterial pathogens interact with MSC and how contact to bacteria influences MSC viability and differentiation potential. In this study we investigated the impact of three different wound infection relevant bacteria, Escherichia coli, Staphylococcus aureus, and Streptococcus pyogenes, and the cell wall components lipopolysaccharide (LPS; Gram-negative bacteria) and lipoteichoic acid (LTA; Gram-positive bacteria) on viability, proliferation, and osteogenic as well as adipogenic differentiationmore » of human adipose tissue-derived mesenchymal stem cells (adMSC). We show that all three tested species were able to attach to and internalize into adMSC. The heat-inactivated Gram-negative E. coli as well as LPS were able to induce proliferation and osteogenic differentiation but reduce adipogenic differentiation of adMSC. Conspicuously, the heat-inactivated Gram-positive species showed the same effects on proliferation and adipogenic differentiation, while its cell wall component LTA exhibited no significant impact on adMSC. Therefore, our data demonstrate that osteogenic and adipogenic differentiation of adMSC is influenced in an oppositional fashion by bacterial antigens and that MSC-governed regeneration is not necessarily reduced under infectious conditions. - Highlights: • Staphylococcus aureus, Streptococcus pyogenes and Escherichia coli bind to and internalize into adMSC. • Heat-inactivated cells of these bacterial species trigger proliferation of adMSC. • Heat-inactivated E. coli and LPS induce osteogenic differentiation of adMSC. • Heat-inactivated E. coli and LPS reduce adipogenic differentiation of adMSC. • LTA does not influence adipogenic or osteogenic differentiation of adMSC.« less

Morphological features of IFN-γ–stimulated mesenchymal stromal cells predict overall immunosuppressive capacity

PubMed Central

Klinker, Matthew W.; Marklein, Ross A.; Lo Surdo, Jessica L.; Wei, Cheng-Hong

2017-01-01

Human mesenchymal stromal cell (MSC) lines can vary significantly in their functional characteristics, and the effectiveness of MSC-based therapeutics may be realized by finding predictive features associated with MSC function. To identify features associated with immunosuppressive capacity in MSCs, we developed a robust in vitro assay that uses principal-component analysis to integrate multidimensional flow cytometry data into a single measurement of MSC-mediated inhibition of T-cell activation. We used this assay to correlate single-cell morphological data with overall immunosuppressive capacity in a cohort of MSC lines derived from different donors and manufacturing conditions. MSC morphology after IFN-γ stimulation significantly correlated with immunosuppressive capacity and accurately predicted the immunosuppressive capacity of MSC lines in a validation cohort. IFN-γ enhanced the immunosuppressive capacity of all MSC lines, and morphology predicted the magnitude of IFN-γ–enhanced immunosuppressive activity. Together, these data identify MSC morphology as a predictive feature of MSC immunosuppressive function. PMID:28283659

No evidence for circulating mesenchymal stem cells in patients with organ injury.

PubMed

Hoogduijn, Martin J; Verstegen, Monique M A; Engela, Anja U; Korevaar, Sander S; Roemeling-van Rhijn, Marieke; Merino, Ana; Franquesa, Marcella; de Jonge, Jeroen; Ijzermans, Jan N; Weimar, Willem; Betjes, Michiel G H; Baan, Carla C; van der Laan, Luc J W

2014-10-01

Mesenchymal stem cells (MSC) are present in the bone marrow, from where they are thought to migrate through the blood stream to the sites of injury. However, virtually all tissues contain resident MSC that may contribute to local regenerative and immunomodulatory processes, thereby hypothetically preempting the need for recruiting MSC through the bloodstream. Although there is some indication for circulating MSC in animal models, there is little solid evidence for the mobilization and migration of MSC in the human circulation. In the present study, we were unable to detect MSC in the blood of healthy individuals. We then searched for MSC in the blood of ten patients with end-stage renal disease, ten patients with end-stage liver disease, and in eight heart transplant patients with biopsy-proven rejection by culturing of mononuclear cells under MSC-supporting culture conditions. In none of these patient categories, MSC were identified in the blood. MSC were, however, found in the blood of a severe trauma patient with multiple fractures, suggesting that disruption of bone marrow leads to the release of MSC into the blood stream. The conclusion of this study is that MSC are not recruited into the circulation in patients with injured solid organs and during aggressive immune responses after transplantation.

Mimicking Mars: a vacuum simulation chamber for testing environmental instrumentation for Mars exploration.

PubMed

Sobrado, J M; Martín-Soler, J; Martín-Gago, J A

2014-03-01

We have built a Mars environmental simulation chamber, designed to test new electromechanical devices and instruments that could be used in space missions. We have developed this environmental system aiming at validating the meteorological station Rover Environment Monitoring Station of NASA's Mars Science Laboratory mission currently installed on Curiosity rover. The vacuum chamber has been built following a modular configuration and operates at pressures ranging from 1000 to 10(-6) mbars, and it is possible to control the gas composition (the atmosphere) within this pressure range. The device (or sample) under study can be irradiated by an ultraviolet source and its temperature can be controlled in the range from 108 to 423 K. As an important improvement with respect to other simulation chambers, the atmospheric gas into the experimental chamber is cooled at the walls by the use of liquid-nitrogen heat exchangers. This chamber incorporates a dust generation mechanism designed to study Martian-dust deposition while modifying the conditions of temperature, and UV irradiated.

INVESTIGATION OF THE HUMIDITY EFFECT ON THE FAC-IR-300 IONIZATION CHAMBER RESPONSE.

PubMed

Mohammadi, Seyed Mostafa; Tavakoli-Anbaran, Hossein

2018-02-01

The free-air ionization chamber is communicating with the ambient air, therefore, the atmospheric parameters such as temperature, pressure and humidity effect on the ionization chamber performance. The free-air ionization chamber, entitled as FAC-IR-300, that design at the Atomic Energy Organization of Iran, AEOI, is required the atmospheric correction factors for correct the chamber reading. In this article, the effect of humidity on the ionization chamber response was investigated. For this reason, was introduced the humidity correction factor, kh. In this article, the Monte Carlo simulation was used to determine the kh factor. The simulation results show in relative humidities between 30% to 80%, the kh factor is equal 0.9970 at 20°C and 0.9975 at 22°C. From the simulation results, at low energy the energy dependence of the kh factor is significant and with increasing energy this dependence is negligible. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Survival of endospores of Bacillus subtilis on spacecraft surfaces under simulated martian environments: implications for the forward contamination of Mars

NASA Technical Reports Server (NTRS)

Schuerger, Andrew C.; Mancinelli, Rocco L.; Kern, Roger G.; Rothschild, Lynn J.; McKay, Christopher P.

2003-01-01

Experiments were conducted in a Mars simulation chamber (MSC) to characterize the survival of endospores of Bacillus subtilis under high UV irradiation and simulated martian conditions. The MSC was used to create Mars surface environments in which pressure (8.5 mb), temperature (-80, -40, -10, or +23 degrees C), gas composition (Earth-normal N2/O2 mix, pure N2, pure CO2, or a Mars gas mix), and UV-VIS-NIR fluence rates (200-1200 nm) were maintained within tight limits. The Mars gas mix was composed of CO2 (95.3%), N2 (2.7%), Ar (1.7%), O2 (0.2%), and water vapor (0.03%). Experiments were conducted to measure the effects of pressure, gas composition, and temperature alone or in combination with Mars-normal UV-VIS-NIR light environments. Endospores of B. subtilis, were deposited on aluminum coupons as monolayers in which the average density applied to coupons was 2.47 x 10(6) bacteria per sample. Populations of B. subtilis placed on aluminum coupons and subjected to an Earth-normal temperature (23 degrees C), pressure (1013 mb), and gas mix (normal N2/O2 ratio) but illuminated with a Mars-normal UV-VIS-NIR spectrum were reduced by over 99.9% after 30 sec exposure to Mars-normal UV fluence rates. However, it required at least 15 min of Mars-normal UV exposure to reduce bacterial populations on aluminum coupons to non-recoverable levels. These results were duplicated when bacteria were exposed to Mars-normal environments of temperature (-10 degrees C), pressure (8.5 mb), gas composition (pure CO2), and UV fluence rates. In other experiments, results indicated that the gas composition of the atmosphere and the temperature of the bacterial monolayers at the time of Mars UV exposure had no effects on the survival of bacterial endospores. But Mars-normal pressures (8.5 mb) were found to reduce survival by approximately 20-35% compared to Earth-normal pressures (1013 mb). The primary implications of these results are (a) that greater than 99.9% of bacterial populations on sun-exposed surfaces of spacecraft are likely to be inactivated within a few tens of seconds to a few minutes on the surface of Mars, and (b) that within a single Mars day under clear-sky conditions bacterial populations on sun-exposed surfaces of spacecraft will be sterilized. Furthermore, these results suggest that the high UV fluence rates on the martian surface can be an important resource in minimizing the forward contamination of Mars. c2003 Elsevier Inc. All rights reserved.

[Mesenchymal stem cells: weapons or dangers for cancer treatment?].

PubMed

Lazennec, Gwendal

2011-03-01

Mesenchymal stem cells (MSC) have attracted recent attention for their cell therapy potential, based in particular on their immunosuppressive properties, which have served as the basis for the treatment of autoimmune diseases. Interestingly, MSC have been used in cell therapy strategies to deliver therapeutical genes. Cell therapy approaches taking advantages of MSC have been proposed, as MSC display a potential tropsim for tumors. However, all these strategies raise a series of questions about the safety of MSC, as MSC could enhance tumor growth and metastasis. This review summarizes recent findngs about MSC in carcinogenesis. © 2011 médecine/sciences - Inserm / SRMS.

Receptor control in mesenchymal stem cell engineering

NASA Astrophysics Data System (ADS)

Dalby, Matthew J.; García, Andrés J.; Salmeron-Sanchez, Manuel

2018-03-01

Materials science offers a powerful tool to control mesenchymal stem cell (MSC) growth and differentiation into functional phenotypes. A complex interplay between the extracellular matrix and growth factors guides MSC phenotypes in vivo. In this Review, we discuss materials-based bioengineering approaches to direct MSC fate in vitro and in vivo, mimicking cell-matrix-growth factor crosstalk. We first scrutinize MSC-matrix interactions and how the properties of a material can be tailored to support MSC growth and differentiation in vitro, with an emphasis on MSC self-renewal mechanisms. We then highlight important growth factor signalling pathways and investigate various materials-based strategies for growth factor presentation and delivery. Integrin-growth factor crosstalk in the context of MSC engineering is introduced, and bioinspired material designs with the potential to control the MSC niche phenotype are considered. Finally, we summarize important milestones on the road to MSC engineering for regenerative medicine.

Transcriptome Analyses of Mosaic (MSC) Mitochondrial Mutants of Cucumber in a Highly Inbred Nuclear Background

PubMed Central

Mróz, Tomasz L.; Eves-van den Akker, Sebastian; Bernat, Agata; Skarzyńska, Agnieszka; Pryszcz, Leszek; Olberg, Madeline; Havey, Michael J.; Bartoszewski, Grzegorz

2018-01-01

Cucumber (Cucumis sativus L.) has a large, paternally transmitted mitochondrial genome. Cucumber plants regenerated from cell cultures occasionally show paternally transmitted mosaic (MSC) phenotypes, characterized by slower growth, chlorotic patterns on the leaves and fruit, lower fertility, and rearrangements in their mitochondrial DNAs (mtDNAs). MSC lines 3, 12, and 16 originated from different cell cultures all established using the highly inbred, wild-type line B. These MSC lines possess different rearrangements and under-represented regions in their mtDNAs. We completed RNA-seq on normalized and non-normalized cDNA libraries from MSC3, MSC12, and MSC16 to study their nuclear gene-expression profiles relative to inbred B. Results from both libraries indicated that gene expression in MSC12 and MSC16 were more similar to each other than MSC3. Forty-one differentially expressed genes (DEGs) were upregulated and one downregulated in the MSC lines relative to B. Gene functional classifications revealed that more than half of these DEGs are associated with stress-response pathways. Consistent with this observation, we detected elevated levels of hydrogen peroxide throughout leaf tissue in all MSC lines compared to wild-type line B. These results demonstrate that independently produced MSC lines with different mitochondrial polymorphisms show unique and shared nuclear responses. This study revealed genes associated with stress response that could become selection targets to develop cucumber cultivars with increased stress tolerance, and further support of cucumber as a model plant to study nuclear-mitochondrial interactions. PMID:29330162

Mesenchymal stromal cells (MSC) from JAK2+ myeloproliferative neoplasms differ from normal MSC and contribute to the maintenance of neoplastic hematopoiesis

PubMed Central

Sánchez-Abarca, Luis Ignacio; Rosón-Burgo, Beatriz; Redondo, Alba; Rico, Ana; Preciado, Silvia; Ortega, Rebeca; Rodríguez, Concepción; Muntión, Sandra; Hernández-Hernández, Ángel; De Las Rivas, Javier; González, Marcos; González Porras, José Ramón; del Cañizo, Consuelo; Sánchez-Guijo, Fermín

2017-01-01

There is evidence of continuous bidirectional cross-talk between malignant cells and bone marrow-derived mesenchymal stromal cells (BM-MSC), which favors the emergence and progression of myeloproliferative neoplastic (MPN) diseases. In the current work we have compared the function and gene expression profile of BM-MSC from healthy donors (HD-MSC) and patients with MPN (JAK2V617F), showing no differences in the morphology, proliferation and differentiation capacity between both groups. However, BM-MSC from MPN expressed higher mean fluorescence intensity (MIF) of CD73, CD44 and CD90, whereas CD105 was lower when compared to controls. Gene expression profile of BM-MSC showed a total of 169 genes that were differentially expressed in BM-MSC from MPN patients compared to HD-MSC. In addition, we studied the ability of BM-MSC to support the growth and survival of hematopoietic stem/progenitor cells (HSPC), showing a significant increase in the number of CFU-GM colonies when MPN-HSPC were co-cultured with MPN-MSC. Furthermore, MPN-MSC showed alteration in the expression of genes associated to the maintenance of hematopoiesis, with an overexpression of SPP1 and NF-kB, and a downregulation of ANGPT1 and THPO. Our results suggest that BM-MSC from JAK2+ patients differ from their normal counterparts and favor the maintenance of malignant clonal hematopoietic cells. PMID:28796790

On the acoustic wedge design and simulation of anechoic chamber

NASA Astrophysics Data System (ADS)

Jiang, Changyong; Zhang, Shangyu; Huang, Lixi

2016-10-01

This study proposes an alternative to the classic wedge design for anechoic chambers, which is the uniform-then-gradient, flat-wall (UGFW) structure. The working mechanisms of the proposed structure and the traditional wedge are analyzed. It is found that their absorption patterns are different. The parameters of both structures are optimized for achieving minimum absorber depth, under the condition of absorbing 99% of normal incident sound energy. It is found that, the UGFW structure achieves a smaller total depth for the cut-off frequencies ranging from 100 Hz to 250 Hz. This paper also proposes a modification for the complex source image (CSI) model for the empirical simulation of anechoic chambers, originally proposed by Bonfiglio et al. [J. Acoust. Soc. Am. 134 (1), 285-291 (2013)]. The modified CSI model considers the non-locally reactive effect of absorbers at oblique incidence, and the improvement is verified by a full, finite-element simulation of a small chamber. With the modified CSI model, the performance of both decorations with the optimized parameters in a large chamber is simulated. The simulation results are analyzed and checked against the tolerance of 1.5 dB deviation from the inverse square law, stipulated in the ISO standard 3745(2003). In terms of the total decoration depth and anechoic chamber performance, the UGFW structure is better than the classic wedge design.

3D Bioprinted Artificial Trachea with Epithelial Cells and Chondrogenic-Differentiated Bone Marrow-Derived Mesenchymal Stem Cells.

PubMed

Bae, Sang-Woo; Lee, Kang-Woog; Park, Jae-Hyun; Lee, JunHee; Jung, Cho-Rok; Yu, JunJie; Kim, Hwi-Yool; Kim, Dae-Hyun

2018-05-31

Tracheal resection has limited applicability. Although various tracheal replacement strategies were performed using artificial prosthesis, synthetic stents and tissue transplantation, the best method in tracheal reconstruction remains to be identified. Recent advances in tissue engineering enabled 3D bioprinting using various biocompatible materials including living cells, thereby making the product clinically applicable. Moreover, clinical interest in mesenchymal stem cell has dramatically increased. Here, rabbit bone marrow-derived mesenchymal stem cells (bMSC) and rabbit respiratory epithelial cells were cultured. The chondrogenic differentiation level of bMSC cultured in regular media (MSC) and that in chondrogenic media (d-MSC) were compared. Dual cell-containing artificial trachea were manufactured using a 3D bioprinting method with epithelial cells and undifferentiated bMSC (MSC group, n = 6) or with epithelial cells and chondrogenic-differentiated bMSC (d-MSC group, n = 6). d-MSC showed a relatively higher level of glycosaminoglycan (GAG) accumulation and chondrogenic marker gene expression than MSC in vitro. Neo-epithelialization and neo-vascularization were observed in all groups in vivo but neo-cartilage formation was only noted in d-MSC. The epithelial cells in the 3D bioprinted artificial trachea were effective in respiratory epithelium regeneration. Chondrogenic-differentiated bMSC had more neo-cartilage formation potential in a short period. Nevertheless, the cartilage formation was observed only in a localized area.

Human adipose mesenchymal stem cells as potent anti-fibrosis therapy for systemic sclerosis.

PubMed

Maria, Alexandre T J; Toupet, Karine; Maumus, Marie; Fonteneau, Guillaume; Le Quellec, Alain; Jorgensen, Christian; Guilpain, Philippe; Noël, Danièle

2016-06-01

Displaying immunosuppressive and trophic properties, mesenchymal stem/stromal cells (MSC) are being evaluated as promising therapeutic options in a variety of autoimmune and degenerative diseases. Although benefits may be expected in systemic sclerosis (SSc), a rare autoimmune disease with fibrosis-related mortality, MSC have yet to be evaluated in this specific condition. While autologous approaches could be inappropriate because of functional alterations in MSC from patients, the objective of the present study was to evaluate allogeneic and xenogeneic MSC in the HOCl-induced model of diffuse SSc. We also questioned the source of human MSC and compared bone marrow- (hBM-MSC) and adipose-derived MSC (hASC). HOCl-challenged BALB/c mice received intravenous injection of BM-MSC from syngeneic BALB/c or allogeneic C57BL/6 mice, and xenogeneic hBM-MSC or hASC (3 donors each). Skin thickness was measured during the experiment. At euthanasia, histology, immunostaining, collagen determination and RT-qPCR were performed in skin and lungs. Xenogeneic hBM-MSC were as effective as allogeneic or syngeneic BM-MSC in decreasing skin thickness, expression of Col1, Col3, α-Sma transcripts, and collagen content in skin and lungs. This anti-fibrotic effect was not associated with MSC migration to injured skin or with long-term MSC survival. Interestingly, compared with hBM-MSC, hASC were significantly more efficient in reducing skin fibrosis, which was related to a stronger reduction of TNFα, IL1β, and enhanced ratio of Mmp1/Timp1 in skin and lung tissues. Using primary cells isolated from 3 murine and 6 human individuals, this preclinical study demonstrated similar therapeutic effects using allogeneic or xenogeneic BM-MSC while ASC exerted potent anti-inflammatory and remodeling properties. This sets the proof-of-concept prompting to evaluate the therapeutic efficacy of allogeneic ASC in SSc patients. Copyright © 2016 Elsevier Ltd. All rights reserved.

S. aureus MscL is a pentamer in vivo but of variable stoichiometries in vitro: implications for detergent-solubilized membrane proteins.

PubMed

Dorwart, Michael R; Wray, Robin; Brautigam, Chad A; Jiang, Youxing; Blount, Paul

2010-12-07

While the bacterial mechanosensitive channel of large conductance (MscL) is the best studied biological mechanosensor and serves as a paradigm for how a protein can sense and respond to membrane tension, the simple matter of its oligomeric state has led to debate, with models ranging from tetramers to hexamers. Indeed, two different oligomeric states of the bacterial mechanosensitive channel MscL have been resolved by X-ray crystallography: The M. tuberculosis channel (MtMscL) is a pentamer, while the S. aureus protein (SaMscL) forms a tetramer. Because several studies suggest that, like MtMscL, the E. coli MscL (EcoMscL) is a pentamer, we re-investigated the oligomeric state of SaMscL. To determine the structural organization of MscL in the cell membrane we developed a disulfide-trapping approach. Surprisingly, we found that virtually all SaMscL channels in vivo are pentameric, indicating this as the physiologically relevant and functional oligomeric state. Complementing our in vivo results, we purified SaMscL and assessed its oligomeric state using three independent approaches (sedimentation equilibrium centrifugation, crosslinking, and light scattering) and established that SaMscL is a pentamer when solubilized in Triton X-100 and C(8)E(5) detergents. However, performing similar experiments on SaMscL solubilized in LDAO, the detergent used in the crystallographic study, confirmed the tetrameric oligomerization resolved by X-ray crystallography. We further demonstrate that this stoichiometric shift is reversible by conventional detergent exchange experiments. Our results firmly establish the pentameric organization of SaMscL in vivo. Furthermore they demonstrate that detergents can alter the subunit stoichiometry of membrane protein complexes in vitro; thus, in vivo assays are necessary to firmly establish a membrane protein's true functionally relevant oligomeric state.

Method and apparatus for simulating atomospheric absorption of solar energy due to water vapor and CO.sub.2

DOEpatents

Sopori, Bhushan L.

1995-01-01

A method and apparatus for improving the accuracy of the simulation of sunlight reaching the earth's surface includes a relatively small heated chamber having an optical inlet and an optical outlet, the chamber having a cavity that can be filled with a heated stream of CO.sub.2 and water vapor. A simulated beam comprising infrared and near infrared light can be directed through the chamber cavity containing the CO.sub.2 and water vapor, whereby the spectral characteristics of the beam are altered so that the output beam from the chamber contains wavelength bands that accurately replicate atmospheric absorption of solar energy due to atmospheric CO.sub.2 and moisture.

Method and apparatus for simulating atmospheric absorption of solar energy due to water vapor and CO{sub 2}

DOEpatents

Sopori, B.L.

1995-06-20

A method and apparatus for improving the accuracy of the simulation of sunlight reaching the earth`s surface includes a relatively small heated chamber having an optical inlet and an optical outlet, the chamber having a cavity that can be filled with a heated stream of CO{sub 2} and water vapor. A simulated beam comprising infrared and near infrared light can be directed through the chamber cavity containing the CO{sub 2} and water vapor, whereby the spectral characteristics of the beam are altered so that the output beam from the chamber contains wavelength bands that accurately replicate atmospheric absorption of solar energy due to atmospheric CO{sub 2} and moisture. 8 figs.

ASPEN+ and economic modeling of equine waste utilization for localized hot water heating via fast pyrolysis

USDA-ARS?s Scientific Manuscript database

ASPEN Plus based simulation models have been developed to design a pyrolysis process for the on-site production and utilization of pyrolysis oil from equine waste at the Equine Rehabilitation Center at Morrisville State College (MSC). The results indicate that utilization of all available Equine Reh...

Global phenotypic characterisation of human platelet lysate expanded MSCs by high-throughput flow cytometry.

PubMed

Reis, Monica; McDonald, David; Nicholson, Lindsay; Godthardt, Kathrin; Knobel, Sebastian; Dickinson, Anne M; Filby, Andrew; Wang, Xiao-Nong

2018-03-02

Mesenchymal stromal cells (MSCs) are a promising cell source to develop cell therapy for many diseases. Human platelet lysate (PLT) is increasingly used as an alternative to foetal calf serum (FCS) for clinical-scale MSC production. To date, the global surface protein expression of PLT-expended MSCs (MSC-PLT) is not known. To investigate this, paired MSC-PLT and MSC-FCS were analysed in parallel using high-throughput flow cytometry for the expression of 356 cell surface proteins. MSC-PLT showed differential surface protein expression compared to their MSC-FCS counterpart. Higher percentage of positive cells was observed in MSC-PLT for 48 surface proteins, of which 13 were significantly enriched on MSC-PLT. This finding was validated using multiparameter flow cytometry and further confirmed by quantitative staining intensity analysis. The enriched surface proteins are relevant to increased proliferation and migration capacity, as well as enhanced chondrogenic and osteogenic differentiation properties. In silico network analysis revealed that these enriched surface proteins are involved in three distinct networks that are associated with inflammatory responses, carbohydrate metabolism and cellular motility. This is the first study reporting differential cell surface protein expression between MSC-PLT and MSC-FSC. Further studies are required to uncover the impact of those enriched proteins on biological functions of MSC-PLT.

Matrix-associated implantation of predifferentiated mesenchymal stem cells versus articular chondrocytes: in vivo results of cartilage repair after 1 year.

PubMed

Marquass, Bastian; Schulz, Ronny; Hepp, Pierre; Zscharnack, Matthias; Aigner, Thomas; Schmidt, Stefanie; Stein, Frank; Richter, Robert; Osterhoff, Georg; Aust, Gabriele; Josten, Christoph; Bader, Augustinus

2011-07-01

The use of predifferentiated mesenchymal stem cells (MSC) leads to better histological results compared with undifferentiated MSC in sheep. This raises the need for a longer term follow-up study and comparison with a clinically established method. We hypothesized that chondrogenic in vitro predifferentiation of autologous MSC embedded in a collagen I hydrogel leads to better structural repair of a chronic osteochondral defect in an ovine stifle joint after 1 year. We further hypothesized that resulting histological results would be comparable with those of chondrocyte-seeded matrix-associated autologous chondrocyte transplantation (MACT). Controlled laboratory study. Predifferentiation period of ovine MSC within collagen gel in vitro was defined by assessment of several cellular and molecular biological parameters. For the animal study, 2 osteochondral lesions (7-mm diameter) were created at the medial femoral condyles of the hind legs in 9 sheep. Implantation of MSC gels was performed 6 weeks after defect creation. Thirty-six defects were divided into 4 treatment groups: (1) chondrogenically predifferentiated MSC gels (pre-MSC gels), (2) undifferentiated MSC gels (un-MSC gels), (3) MACT gels, and (4) untreated controls (UC). Histological, immunohistochemical, and radiological evaluations followed after 12 months. After 12 months in vivo, pre-MSC gels showed significantly better histological outcome compared with un-MSC gels and UC. Compared with MACT gels, the overall scores were higher for O'Driscoll and International Cartilage Repair Society (ICRS). The repair tissue of the pre-MSC group showed immunohistochemical detection of interzonal collagen type II staining. Radiological evaluation supported superior bonding of pre-MSC gels to perilesional native cartilage. Compared with previous work by our group, no degradation of the repair tissue between 6 and 12 months in vivo, particularly in pre-MSC gels, was observed. Repair of chronic osteochondral defects with collagen hydrogels composed of chondrogenically predifferentiated MSC shows no signs of degradation after 1 year in vivo. In addition, pre-MSC gels lead to partially superior histological results compared with articular chondrocytes. The results suggest an encouraging method for future treatment of focal osteochondral defects without donor site morbidity by harvesting articular chondrocytes.

Evaluation of Heat Recuperation in a Concentric Hydrogen Reduction Reactor

NASA Technical Reports Server (NTRS)

Linne, Diane; Kleinhenz, Julie; Hegde, Uday

2012-01-01

Heat recuperation in an ISRU reactor system involves the recovery of heat from a reacted regolith batch by transferring this energy into a batch of fresh regolith. One concept for a hydrogen reduction reactor is a concentric chamber design where heat is transferred from the inner, reaction chamber into fresh regolith in the outer, recuperation chamber. This concept was tested and analyzed to define the overall benefit compared to a more traditional single chamber batch reactor. Data was gathered for heat-up and recuperation in the inner chamber alone, simulating a single chamber design, as well as recuperation into the outer chamber, simulating a dual chamber design. Experimental data was also used to improve two analytical models, with good agreement for temperature behavior during recuperation, calculated mass of the reactor concepts, and energy required during heat-up. The five tests, performed using JSC-1A regolith simulant, also explored the effectiveness of helium gas fluidization, hydrogen gas fluidization, and vibrational fluidization. Results indicate that higher hydrogen volumetric flow rates are required compared to helium for complete fluidization and mixing, and that vibrational fluidization may provide equivalent mixing while eliminating the need to flow large amounts of excess hydrogen. Analysis of the total energy required for heat-up and steady-state operations for a variety of conditions and assumptions shows that the dual-chamber concept requires the same or more energy than the single chamber concept. With no clear energy savings, the added mass and complexity of the dual-chamber makes it unlikely that this design concept will provide any added benefit to the overall ISRU oxygen production system.

EFFECTIVENESS OF A COMPREHENSIVE MENTAL SKILLS CURRICULUM IN ENHANCING SURGICAL PERFORMANCE: RESULTS OF A RANDOMIZED CONTROLLED TRIAL

PubMed Central

Stefanidis, Dimitrios; Anton, Nicholas E; Howley, Lisa D; Bean, Eric; Yurco, Ashley; Pimentel, Manuel E; Davis, Cameron K

2016-01-01

Introduction We hypothesized that the implementation of a novel mental skills curriculum (MSC) during laparoscopic simulator training would improve mental skills and performance, and decrease stress. Methods Sixty volunteer novices were randomized into intervention and control groups. All participants received FLS training while the intervention group also participated in the MSC. Skill transfer and retention were assessed on a live porcine model after training and 2 months later, respectively. Performance was assessed using the Test of Performance Strategies-2 (TOPS-2) for mental skills, FLS metrics for laparoscopic performance, and the State Trait Anxiety Inventory (STAI-6) and heart rate (HR) for stress. Results Fifty-five participants (92%) completed training and the transfer test, and 46 (77%) the retention test. There were no significant differences between groups at baseline. Compared to controls the intervention group significantly improved their mental skill use, demonstrated higher laparoscopic skill improvement during retention, and reported less stress during the transfer test. Conclusions The MSC implemented in this study effectively enhanced participants’ mental skill use, reduced cognitive stress in the operating room with a small impact on laparoscopic performance. PMID:27908500

Pathogen-free, plasma-poor platelet lysate and expansion of human mesenchymal stem cells.

PubMed

Iudicone, Paola; Fioravanti, Daniela; Bonanno, Giuseppina; Miceli, Michelina; Lavorino, Claudio; Totta, Pierangela; Frati, Luigi; Nuti, Marianna; Pierelli, Luca

2014-01-27

Supplements to support clinical-grade cultures of mesenchymal stem cells (MSC) are required to promote growth and expansion of these cells. Platelet lysate (PL) is a human blood component which may replace animal serum in MSC cultures being rich in various growth factors. Here, we describe a plasma poor pathogen-free platelet lysate obtained by pooling 12 platelet (PLT) units, to produce a standardized and safe supplement for clinical-grade expansion of MSC. PL lots were obtained by combining 2 6-unit PLT pools in additive solution (AS) following a transfusional-based procedure including pathogen inactivation (PI) by Intercept technology and 3 cycles of freezing/thawing, followed by membrane removal. Three PI-PL and 3 control PL lots were produced to compare their ability to sustain bone marrow derived MSC selection and expansion. Moreover, two further PL, subjected to PI or not, were also produced starting from the same initial PLT pools to evaluate the impact of PI on growth factor concentration and capacity to sustain cell growth. Additional PI-PL lots were used for comparison with fetal bovine serum (FBS) on MSC expansion. Immunoregulatory properties of PI-PL-generated MSC were documented in vitro by mixed lymphocyte culture (MLC) and peripheral blood mononuclear cells (PBMC) mitogen induced proliferation. PI-PL and PL control lots had similar concentrations of 4 well-described growth factors endowed with MSC stimulating ability. Initial growth and MSC expansion by PI-PL and PL controls were comparable either using different MSC populations or in head to head experiments. Moreover, PI-PL and PL control sustained similar MSC growth of frozen/thawed MSC. Multilineage differentiation of PI-derived and PI-PL-derived MSC were maintained in any MSC cultures as well as their immunoregulatory properties. Finally, no direct impact of PI on growth factor concentration and MSC growth support was observed, whereas the capacity of FBS to sustain MSC expansion in basic medium was irrelevant as compared to PL and PI-PL. The replacement of animal additives with human supplements is a basic issue in MSC ex vivo production. PI-PL represents a standardized, plasma-poor, human preparation which appears as a safe and good candidate to stimulate MSC growth in clinical-scale cultures.

Pathogen-free, plasma-poor platelet lysate and expansion of human mesenchymal stem cells

PubMed Central

2014-01-01

Background Supplements to support clinical-grade cultures of mesenchymal stem cells (MSC) are required to promote growth and expansion of these cells. Platelet lysate (PL) is a human blood component which may replace animal serum in MSC cultures being rich in various growth factors. Here, we describe a plasma poor pathogen-free platelet lysate obtained by pooling 12 platelet (PLT) units, to produce a standardized and safe supplement for clinical-grade expansion of MSC. Methods PL lots were obtained by combining 2 6-unit PLT pools in additive solution (AS) following a transfusional-based procedure including pathogen inactivation (PI) by Intercept technology and 3 cycles of freezing/thawing, followed by membrane removal. Three PI-PL and 3 control PL lots were produced to compare their ability to sustain bone marrow derived MSC selection and expansion. Moreover, two further PL, subjected to PI or not, were also produced starting from the same initial PLT pools to evaluate the impact of PI on growth factor concentration and capacity to sustain cell growth. Additional PI-PL lots were used for comparison with fetal bovine serum (FBS) on MSC expansion. Immunoregulatory properties of PI-PL-generated MSC were documented in vitro by mixed lymphocyte culture (MLC) and peripheral blood mononuclear cells (PBMC) mitogen induced proliferation. Results PI-PL and PL control lots had similar concentrations of 4 well-described growth factors endowed with MSC stimulating ability. Initial growth and MSC expansion by PI-PL and PL controls were comparable either using different MSC populations or in head to head experiments. Moreover, PI-PL and PL control sustained similar MSC growth of frozen/thawed MSC. Multilineage differentiation of PI-derived and PI-PL-derived MSC were maintained in any MSC cultures as well as their immunoregulatory properties. Finally, no direct impact of PI on growth factor concentration and MSC growth support was observed, whereas the capacity of FBS to sustain MSC expansion in basic medium was irrelevant as compared to PL and PI-PL. Conclusion The replacement of animal additives with human supplements is a basic issue in MSC ex vivo production. PI-PL represents a standardized, plasma-poor, human preparation which appears as a safe and good candidate to stimulate MSC growth in clinical-scale cultures. PMID:24467837

Development of the AFRL Aircrew Perfomance and Protection Data Bank

DTIC Science & Technology

2007-12-01

Growth model and statistical model of hypobaric chamber simulations. It offers a quick and readily accessible online DCS risk assessment tool for...are used for the DCS prediction instead of the original model. ADRAC is based on more than 20 years of hypobaric chamber studies using human...prediction based on the combined Bubble Growth model and statistical model of hypobaric chamber simulations was integrated into the Data Bank. It

Numerical Investigation of the Impact of the Compressor Operation Mode on Working Process of the Combustion Chamber

NASA Astrophysics Data System (ADS)

Orlov, M. Yu; Lukachev, S. V.; Anisimov, V. M.

2018-01-01

The method of integrated compressor/combustor simulation was used to investigate the impact of flow distortion, appeared due to compressor blades, during the combustion chamber workflow. The method was improved in terms of generating a common grid and of principles of the boundary conditions settings. The geometric model includes four geometric volume bodies: guide vanes of the penultimate stage of high-pressure compressor, the impeller and guide vanes of the last stage and the flow path of combustion chamber. The calculation was carried out for some operation mode of the engine (nominal, 0.7 of nominal and 0.5 of nominal regimes) with and without compressor. The results were compared with the results of combustion chamber simulation without the compressor. Simulations showed that blade wakes extend up to the flame tube head. These wakes influence on the flame tongue, pressure field, temperature and velocity in the recirculation-mixing zone. It can influence on combustion efficiency, ecological performance and on temperature field at the combustor outlet. Thus, the simulations, which take into account combustion chamber and compressor, are more fully represent the characteristics of the working process of the combustion chamber and increase the efficiency of the design of new products.

Plasmid-based genetic modification of human bone marrow-derived stromal cells: analysis of cell survival and transgene expression after transplantation in rat spinal cord

PubMed Central

Ronsyn, Mark W; Daans, Jasmijn; Spaepen, Gie; Chatterjee, Shyama; Vermeulen, Katrien; D'Haese, Patrick; Van Tendeloo, Viggo FI; Van Marck, Eric; Ysebaert, Dirk; Berneman, Zwi N; Jorens, Philippe G; Ponsaerts, Peter

2007-01-01

Background Bone marrow-derived stromal cells (MSC) are attractive targets for ex vivo cell and gene therapy. In this context, we investigated the feasibility of a plasmid-based strategy for genetic modification of human (h)MSC with enhanced green fluorescent protein (EGFP) and neurotrophin (NT)3. Three genetically modified hMSC lines (EGFP, NT3, NT3-EGFP) were established and used to study cell survival and transgene expression following transplantation in rat spinal cord. Results First, we demonstrate long-term survival of transplanted hMSC-EGFP cells in rat spinal cord under, but not without, appropriate immune suppression. Next, we examined the stability of EGFP or NT3 transgene expression following transplantation of hMSC-EGFP, hMSC-NT3 and hMSC-NT3-EGFP in rat spinal cord. While in vivo EGFP mRNA and protein expression by transplanted hMSC-EGFP cells was readily detectable at different time points post-transplantation, in vivo NT3 mRNA expression by hMSC-NT3 cells and in vivo EGFP protein expression by hMSC-NT3-EGFP cells was, respectively, undetectable or declined rapidly between day 1 and 7 post-transplantation. Further investigation revealed that the observed in vivo decline of EGFP protein expression by hMSC-NT3-EGFP cells: (i) was associated with a decrease in transgenic NT3-EGFP mRNA expression as suggested following laser capture micro-dissection analysis of hMSC-NT3-EGFP cell transplants at day 1 and day 7 post-transplantation, (ii) did not occur when hMSC-NT3-EGFP cells were transplanted subcutaneously, and (iii) was reversed upon re-establishment of hMSC-NT3-EGFP cell cultures at 2 weeks post-transplantation. Finally, because we observed a slowly progressing tumour growth following transplantation of all our hMSC cell transplants, we here demonstrate that omitting immune suppressive therapy is sufficient to prevent further tumour growth and to eradicate malignant xenogeneic cell transplants. Conclusion In this study, we demonstrate that genetically modified hMSC lines can survive in healthy rat spinal cord over at least 3 weeks by using adequate immune suppression and can serve as vehicles for transgene expression. However, before genetically modified hMSC can potentially be used in a clinical setting to treat spinal cord injuries, more research on standardisation of hMSC culture and genetic modification needs to be done in order to prevent tumour formation and transgene silencing in vivo. PMID:18078525

Plasmid-based genetic modification of human bone marrow-derived stromal cells: analysis of cell survival and transgene expression after transplantation in rat spinal cord.

PubMed

Ronsyn, Mark W; Daans, Jasmijn; Spaepen, Gie; Chatterjee, Shyama; Vermeulen, Katrien; D'Haese, Patrick; Van Tendeloo, Viggo Fi; Van Marck, Eric; Ysebaert, Dirk; Berneman, Zwi N; Jorens, Philippe G; Ponsaerts, Peter

2007-12-14

Bone marrow-derived stromal cells (MSC) are attractive targets for ex vivo cell and gene therapy. In this context, we investigated the feasibility of a plasmid-based strategy for genetic modification of human (h)MSC with enhanced green fluorescent protein (EGFP) and neurotrophin (NT)3. Three genetically modified hMSC lines (EGFP, NT3, NT3-EGFP) were established and used to study cell survival and transgene expression following transplantation in rat spinal cord. First, we demonstrate long-term survival of transplanted hMSC-EGFP cells in rat spinal cord under, but not without, appropriate immune suppression. Next, we examined the stability of EGFP or NT3 transgene expression following transplantation of hMSC-EGFP, hMSC-NT3 and hMSC-NT3-EGFP in rat spinal cord. While in vivo EGFP mRNA and protein expression by transplanted hMSC-EGFP cells was readily detectable at different time points post-transplantation, in vivo NT3 mRNA expression by hMSC-NT3 cells and in vivo EGFP protein expression by hMSC-NT3-EGFP cells was, respectively, undetectable or declined rapidly between day 1 and 7 post-transplantation. Further investigation revealed that the observed in vivo decline of EGFP protein expression by hMSC-NT3-EGFP cells: (i) was associated with a decrease in transgenic NT3-EGFP mRNA expression as suggested following laser capture micro-dissection analysis of hMSC-NT3-EGFP cell transplants at day 1 and day 7 post-transplantation, (ii) did not occur when hMSC-NT3-EGFP cells were transplanted subcutaneously, and (iii) was reversed upon re-establishment of hMSC-NT3-EGFP cell cultures at 2 weeks post-transplantation. Finally, because we observed a slowly progressing tumour growth following transplantation of all our hMSC cell transplants, we here demonstrate that omitting immune suppressive therapy is sufficient to prevent further tumour growth and to eradicate malignant xenogeneic cell transplants. In this study, we demonstrate that genetically modified hMSC lines can survive in healthy rat spinal cord over at least 3 weeks by using adequate immune suppression and can serve as vehicles for transgene expression. However, before genetically modified hMSC can potentially be used in a clinical setting to treat spinal cord injuries, more research on standardisation of hMSC culture and genetic modification needs to be done in order to prevent tumour formation and transgene silencing in vivo.

Inflight - Apollo XI (Mission Control Center [MCC]) - MSC

NASA Image and Video Library

1969-07-24

S69-40302 (24 July 1969) --- A group of NASA and Manned Spacecraft Center (MSC) officials join in with the flight controllers in the Mission Operations Control Room (MOCR) in the Mission Control Center (MCC), Building 30, in celebrating the successful conclusion of the Apollo 11 lunar landing mission. From left foreground are Dr. Maxime A. Faget, MSC Director of Engineering and Development; George S. Trimble, MSC Deputy Director; Dr. Christopher C. Kraft Jr., MSC Director of Flight Operations; Julian Scheer (in back), Assistant Administrator, Office of Public Affairs, NASA Headquarters; George M. Low, Manager, Apollo Spacecraft Program, MSC; Dr. Robert R. Gilruth, MSC Director; and Charles W. Mathews, Deputy Associate Administrator, Office of Manned Space Flight, NASA Headquarters.

Three MSC officials hold discussion in Mission Control room during Gemini 11

NASA Image and Video Library

1966-09-12

S66-52754 (12 Sept. 1966) --- Three key Manned Spacecraft Center (MSC) officials hold discussion in the Mission Control room during Gemini-11 activity. Left to right, are Donald K. Slayton, MSC Director of Flight Crew Operations; astronaut Alan B. Shepard Jr., Chief, MSC Astronaut Office; and George M. Low, MSC Deputy Director. Photo credit: NASA

Zero-valent iron particles embedded on the mesoporous silica-carbon for chromium (VI) removal from aqueous solution

NASA Astrophysics Data System (ADS)

Xiong, Kun; Gao, Yuan; Zhou, Lin; Zhang, Xianming

2016-09-01

Nanoscale zero-valent iron (nZVI) particles were embedded on the walls of mesoporous silica-carbon (MSC) under the conditions of high-temperature carbonization and reduction and used to remove chromium (VI) from aqueous solution. The structure and textural properties of nZVI-MSC were characterized by the powder X-ray diffraction, transmission electron microscopy and N2 adsorption and desorption. The results show that nZVI-MSC has highly ordered mesoporous structure and large surface area, indistinguishable with that of MSC. Compared with the support MSC and iron particles supported on the activated carbon (nZVI/AC), nZVI-MSC exhibited much higher Cr(VI) removal efficiency with about 98 %. The removal process obeys a pseudo first-order model. Such excellent performance of nZVI-MSC could be ascribed to the large surface and iron particles embedded on the walls of the MSC, forming an intimate contact with the MSC. It is proposed that this feature might create certain micro-electrode on the interface of iron particles and MSC, which prevented the formation of metal oxide on the surface and provided fresh Fe surface for Cr(VI) removal.

Targeting Murine Mesenchymal Stem Cells to Kidney Injury Molecule-1 Improves Their Therapeutic Efficacy in Chronic Ischemic Kidney Injury.

PubMed

Zou, Xiangyu; Jiang, Kai; Puranik, Amrutesh S; Jordan, Kyra L; Tang, Hui; Zhu, Xiangyang; Lerman, Lilach O

2018-05-01

Mesenchymal stem cells (MSC) have been experimentally used for kidney repair, but modest retention limits their efficacy. Cell-surface coating allows modulating MSC homing and interaction with target cells. We coated mouse adipose tissue-derived MSC with antibodies directed against kidney injury molecule-1 (ab-KIM1), which is upregulated in injured kidneys, and tested the hypothesis that this would enhance their therapeutic effects in ischemic kidney injury. Untreated MSC, ab-KIM1-coated MSC (KIM-MSC), or vehicle, were injected systemically into the carotid artery of 2-kidneys, 1-clip mice 2 weeks after surgery. MSC retention in different organs was explored 24 hours, 48 hours, or 2 weeks after injection. Renal volume, perfusion, and oxygenation were studied 2 weeks after injection using magnetic resonance imaging in vivo, and renal inflammation, apoptosis, capillary density, and fibrosis ex vivo. The ab-KIM1 coating had little effect on MSC viability or proliferation. The stenotic kidney showed upregulated KIM1 expression, selective homing, and greater retention of KIM-MSC compared to untreated MSC and compared to other organs. KIM-MSC-injected mice improved renal perfusion and capillary density, and attenuated oxidative damage, apoptosis, and fibrosis compared to mice treated with vehicle or with native MSC. In conclusion, MSC coating with ab-KIM1 increased their retention in the ischemic kidney and enhanced their therapeutic efficacy. This novel method may be useful to selectively target injured kidneys, and supports further development of strategies to enhance cell-based treatment of ischemic kidney injury. Stem Cells Translational Medicine 2018;7:394-403. © 2018 The Authors Stem Cells Translational Medicine published by Wiley Periodicals, Inc. on behalf of AlphaMed Press.

Mechano-growth factor induces migration of rat mesenchymal stem cells by altering its mechanical properties and activating ERK pathway

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Jiamin; Wu, Kewen; Lin, Feng

2013-11-08

Highlights: •MGF induced the migration of rat MSC in a concentration-dependent manner. •MGF enhanced the mechanical properties of rMSC in inducing its migration. •MGF activated the ERK 1/2 signaling pathway of rMSC in inducing its migration. •rMSC mechanics may synergy with ERK 1/2 pathway in MGF-induced rMSC migration. -- Abstract: Mechano-growth factor (MGF) generated by cells in response to mechanical stimulation has been identified as a mechano effector molecule, playing a key role in regulating mesenchymal stem cell (MSC) function, including proliferation and migration. However, the mechanism(s) underlying how MGF-induced MSC migration occurs is still unclear. In the present study,more » MGF motivated migration of rat MSCs (rMSCs) in a concentration-dependent manner and optimal concentration of MGF at 50 ng/mL (defined as MGF treatment in this paper) was demonstrated. Notably, enhancement of mechanical properties that is pertinent to cell migration, such as cell traction force and cell stiffness were found to respond to MGF treatment. Furthermore, MGF increased phosphorylation of extracellular signal-regulated kinase (ERK), ERK inhibitor (i.e., PD98059) suppressed ERK phosphorylation, and abolished MGF-induced rMSC migration were found, demonstrating that ERK is involved molecule for MGF-induced rMSC migration. These in vitro evidences of MGF-induced rMSC migration and its direct link to altering rMSC mechanics and activating the ERK pathway, uncover the underlying biomechanical and biological mechanisms of MGF-induced rMSC migration, which may help find MGF-based application of MSC in clinical therapeutics.« less

Anti-Inflammatory Effects of Adult Stem Cells in Sustained Lung Injury: A Comparative Study

PubMed Central

Moodley, Yuben; Vaghjiani, Vijesh; Chan, James; Baltic, Svetlana; Ryan, Marisa; Tchongue, Jorge; Samuel, Chrishan S.; Murthi, Padma; Parolini, Ornella; Manuelpillai, Ursula

2013-01-01

Lung diseases are a major cause of global morbidity and mortality that are treated with limited efficacy. Recently stem cell therapies have been shown to effectively treat animal models of lung disease. However, there are limitations to the translation of these cell therapies to clinical disease. Studies have shown that delayed treatment of animal models does not improve outcomes and that the models do not reflect the repeated injury that is present in most lung diseases. We tested the efficacy of amnion mesenchymal stem cells (AM-MSC), bone marrow MSC (BM-MSC) and human amniotic epithelial cells (hAEC) in C57BL/6 mice using a repeat dose bleomycin-induced model of lung injury that better reflects the repeat injury seen in lung diseases. The dual bleomycin dose led to significantly higher levels of inflammation and fibrosis in the mouse lung compared to a single bleomycin dose. Intravenously infused stem cells were present in the lung in similar numbers at days 7 and 21 post cell injection. In addition, stem cell injection resulted in a significant decrease in inflammatory cell infiltrate and a reduction in IL-1 (AM-MSC), IL-6 (AM-MSC, BM-MSC, hAEC) and TNF-α (AM-MSC). The only trophic factor tested that increased following stem cell injection was IL-1RA (AM-MSC). IL-1RA levels may be modulated by GM-CSF produced by AM-MSC. Furthermore, only AM-MSC reduced collagen deposition and increased MMP-9 activity in the lung although there was a reduction of the pro-fibrogenic cytokine TGF-β following BM-MSC, AM-MSC and hAEC treatment. Therefore, AM-MSC may be more effective in reducing injury following delayed injection in the setting of repeated lung injury. PMID:23936322

Mesenchymal Stromal Cell Therapy in Crohn's Disease.

PubMed

Forbes, Geoffrey M

2017-01-01

Mesenchymal stromal cells (MSC) are multipotent adult stem cells with immunomodulatory properties. They uniquely express HLA class I antigen at a low level, and do not express HLA class II. Hence, for allogeneic administration, donor to recipient matching is not required; yet a prolonged chimeric state does not occur. Contrary to haematopoietic stem cell transplantation, cytotoxic drug therapy is not required to harvest, or administer, cells. Key Messages: MSC are obtained from marrow, adipose tissue or placenta. In our centre, MSC are isolated from a 10 ml donor marrow aspirate, by virtue of their adherence to plastic. They are expanded in culture, cryopreserved, and subjected to strict quality controls before release for intravenous administration. These activities occur in a dedicated, nationally accredited, laboratory. Initial observations of allogeneic MSC efficacy were in graft-versus-host disease. Both autologous and allogeneic MSC have since been evaluated in biologic refractory luminal and fistulising Crohn's disease (CD). Data from early-phase studies have suggested efficacy for luminal disease when allogeneic MSC were given intravenously and also suggested efficacy for fistulising disease when either allogeneic or autologous MSC were administered into fistulas. MSC treatment is not reported to have caused serious adverse events. Although in vitro criteria for defining MSC exist, a major challenge lies in how to define MSC for clinical use. MSC function in vivo is likely to be dependent upon donor immunological characteristics, and widely varying manufacturing processes between laboratories. MSC dose, frequency of administration, stage of disease, and presence of concomitant immunosuppression also require to be defined. MSC therapy may have future utility in CD, but considerable work is first required to determine appropriate phenotypic and functional characteristics of administered cells. © 2017 S. Karger AG, Basel.

Intercellular cytosolic transfer correlates with mesenchymal stromal cell rescue of umbilical cord blood cell viability during ex vivo expansion

PubMed Central

Chu, Pat P. Y.; Bari, Sudipto; Fan, Xiubo; Gay, Florence P. H.; Ang, Justina M. L.; Chiu, Gigi N. C.; Lim, Sai K.; Hwang, William Y. K.

2012-01-01

Background aims. Mesenchymal stromal cells (MSC) have been observed to participate in tissue repair and to have growth-promoting effects on ex vivo co-culture with other stem cells. Methods. In order to evaluate the mechanism of MSC support on ex vivo cultures, we performed co-culture of MSC with umbilical cord blood (UCB) mononuclear cells (MNC) (UCB-MNC). Results. Significant enhancement in cell growth correlating with cell viability was noted with MSC co-culture (defined by double-negative staining for Annexin-V and 7-AAD; P<0.01). This was associated with significant enhancement of mitochondrial membrane potential (P<0.01). We postulated that intercellular transfer of cytosolic substances between MSC and UCB-MNC could be one mechanism mediating the support. Using MSC endogenously expressing green fluorescent protein (GFP) or labeled with quantum dots (QD), we performed co-culture of UCB-MNC with these MSC. Transfer of these GFP and QD was observed from MSC to UCB-MNC as early as 24 h post co-culture. Transwell experiments revealed that direct contact between MSC and UCB-MNC was necessary for both transfer and viability support. UCB-MNC tightly adherent to the MSC layer exhibited the most optimal transfer and rescue of cell viability. DNA analysis of the viable, GFP transfer-positive UCB-MNC ruled out MSC transdifferentiation or MSC-UCB fusion. In addition, there was statistical correlation between higher levels of cytosolic transfer and enhanced UCB-MNC viability (P< 0.0001). Conclusions. Collectively, the data suggest that intercellular transfer of cytosolic materials could be one novel mechanism for preventing UCB cell death in MSC co-culture. PMID:22775077

Mimicking Mars: A vacuum simulation chamber for testing environmental instrumentation for Mars exploration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sobrado, J. M., E-mail: sobradovj@inta.es; Martín-Soler, J.; Martín-Gago, J. A.

We have built a Mars environmental simulation chamber, designed to test new electromechanical devices and instruments that could be used in space missions. We have developed this environmental system aiming at validating the meteorological station Rover Environment Monitoring Station of NASA's Mars Science Laboratory mission currently installed on Curiosity rover. The vacuum chamber has been built following a modular configuration and operates at pressures ranging from 1000 to 10{sup −6} mbars, and it is possible to control the gas composition (the atmosphere) within this pressure range. The device (or sample) under study can be irradiated by an ultraviolet source andmore » its temperature can be controlled in the range from 108 to 423 K. As an important improvement with respect to other simulation chambers, the atmospheric gas into the experimental chamber is cooled at the walls by the use of liquid-nitrogen heat exchangers. This chamber incorporates a dust generation mechanism designed to study Martian-dust deposition while modifying the conditions of temperature, and UV irradiated.« less

The association of human mesenchymal stem cells with BMP-7 improves bone regeneration of critical-size segmental bone defects in athymic rats.

PubMed

Burastero, Giorgio; Scarfì, Sonia; Ferraris, Chiara; Fresia, Chiara; Sessarego, Nadia; Fruscione, Floriana; Monetti, Francesco; Scarfò, Francesca; Schupbach, Peter; Podestà, Marina; Grappiolo, Guido; Zocchi, Elena

2010-07-01

Critical size segmental bone defects are still a major challenge in reconstructive orthopedic surgery. Transplantation of human mesenchymal stem cells (hMSC) has been proposed as an alternative to autogenous bone graft, as MSC can be expanded in vitro and induced to differentiate into bone-regenerating osteoblasts by several bone morphogenetic proteins (BMP). The aim of this study was to investigate whether the association of hMSC and BMP-7, with providing the necessary scaffold to fill the bone loss, improved bone regeneration in a rat model of critical size segmental bone defect, compared to treatment with either hMSC or BMP-7 and the matrix. In addition, we tested whether pre-treatment of hMSC with cyclic ADP-ribose (cADPR), an intracellular Ca2+ mobilizer previously shown to accelerate the in vitro expansion of hMSC (Scarfì S et al, Stem Cells, 2008), affected the osteoinductive capacity of the cells in vivo. X-ray analysis, performed 2, 10 and 16 weeks after transplantation, revealed a significantly higher score in the rats treated with hMSC and BMP-7 compared to controls, receiving either hMSC or BMP-7. Microtomography and histological analysis, performed 16weeks after transplantation, confirmed the improved bone regeneration in the animals treated with the association of hMSC and BMP-7 compared to controls. Pre-treatment with cADPR to stimulate hMSC proliferation in vitro did not affect the bone regenerating capacity of the cells in vivo. These results indicate that the association of in vitro expanded hMSC with BMP-7 provide a better osteoinductive graft compared to either hMSC or BMP-7 alone. Moreover, cADPR may be used to stimulate hMSC proliferation in vitro in order to reduce the time required to obtain a transplantable number of cells, with no adverse effect on the bone regenerating capacity of hMSC. 2010 Elsevier Inc. All rights reserved.

Hypoxic Preconditioning Results in Increased Motility and Improved Therapeutic Potential of Human Mesenchymal Stem Cells

PubMed Central

Rosová, Ivana; Dao, Mo; Capoccia, Ben; Link, Daniel; Nolta, Jan A.

2010-01-01

Mesenchymal stem cells (MSC) are adult multipotent cells found in bone marrow, adipose tissue, and other adult tissues. MSC have been shown to improve regeneration of injured tissues in vivo, but the mechanisms remain unclear. Typically, MSC are cultured under ambient, or normoxic, conditions (21% oxygen). However, the physiological niches for MSC in the bone marrow and other sites have much lower oxygen tension. When used as a therapeutic tool to repair tissue injuries, MSC cultured in standard conditions must adapt from 21% oxygen in culture to less than 1% oxygen in the ischemic tissue. We therefore examined the effects of preculturing human bone marrow-derived MSC in hypoxic conditions (1%–3% oxygen) to elucidate the best conditions that enhance their tissue regenerative potential. We demonstrated that MSC cultured in hypoxia activate the Akt signaling pathway while maintaining their viability and cell cycle rates. We also showed that MSC cultured in hypoxia induced expression of cMet, the major receptor for hepatocyte growth factor (HGF), and enhanced cMet signaling. MSC cultured in hypoxic conditions increased their migration rates. Since migration and HGF responsiveness are thought to be key mediators of MSC recruitment and/or activation in vivo, we next examined the tissue regenerative potential of MSC cultured under hypoxic conditions, using a murine hind limb ischemia model. We showed that local expression of HGF is increased in ischemic muscle in this model. Intra-arterial injection of MSC cultured in either normoxic or hypoxic conditions 24 hours after surgical induction of hind limb ischemia enhanced revascularization compared with saline controls. However, restoration of blood flow was observed significantly earlier in mice that had been injected with hypoxic preconditioned MSC. Collectively, these data suggest that preculturing MSC under hypoxic conditions prior to transplantation improves their tissue regenerative potential. PMID:18511601

Secretomes from bone marrow-derived mesenchymal stromal cells enhance periodontal tissue regeneration.

PubMed

Kawai, Takamasa; Katagiri, Wataru; Osugi, Masashi; Sugimura, Yukiko; Hibi, Hideharu; Ueda, Minoru

2015-04-01

Periodontal tissue regeneration with the use of mesenchymal stromal cells (MSCs) has been regarded as a future cell-based therapy. However, low survival rates and the potential tumorigenicity of implanted MSCs could undermine the efficacy of cell-based therapy. The use of conditioned media from MSCs (MSC-CM) may be a feasible approach to overcome these limitations. The aim of this study was to confirm the effect of MSC-CM on periodontal regeneration. MSC-CM were collected during their cultivation. The concentrations of the growth factors in MSC-CM were measured with the use of enzyme-linked immunoassay. Rat MSCs (rMSCs) and human umbilical vein endothelial cells cultured in MSC-CM were assessed on wound-healing and angiogenesis. The expressions of osteogenetic- and angiogenic-related genes of rMSCs cultured in MSC-CM were quantified by means of real-time reverse transcriptase-polymerase chain reaction analysis. In vivo, periodontal defects were prepared in the rat models and the collagen sponges with MSC-CM were implanted. MSC-CM includes insulin-like growth factor-1, vascular endothelial growth factor, transforming growth factor-β1 and hepatocyte growth factor. In vitro, wound-healing and angiogenesis increased significantly in MSC-CM. The levels of expression of osteogenetic- and angiogenic-related genes were significantly upregulated in rMSCs cultured with MSC-CM. In vivo, in the MSC-CM group, 2 weeks after implantation, immunohistochemical analysis showed several CD31-, CD105-or FLK-1-positive cells occurring frequently. At 4 weeks after implantation, regenerated periodontal tissue was observed in MSC-CM groups. The use of MSC-CM may be an alternative therapy for periodontal tissue regeneration because several cytokines included in MSC-CM will contribute to many processes of complicated periodontal tissue regeneration. Copyright © 2015 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

Inflammation and Toll-like receptor ligation differentially affect the osteogenic potential of human mesenchymal stromal cells depending on their tissue origin.

PubMed

Raicevic, Gordana; Najar, Mehdi; Pieters, Karlien; De Bruyn, Cecile; Meuleman, Nathalie; Bron, Dominique; Toungouz, Michel; Lagneaux, Laurence

2012-07-01

Mesenchymal stromal cells (MSCs) can be isolated not only from bone marrow (BM) but also from other tissues, including adipose tissue (AT) and umbilical cord Wharton's Jelly (WJ). Thanks to their ability to differentiate into various cell types, MSC are considered attractive candidates for cell-based regenerative therapy. In degenerative clinical settings, inflammation or infection is often involved. In the present work, we hypothesized that an inflammatory environment and/or Toll-like receptor (TLR) ligation could affect the MSC differentiation potential. MSC were isolated from BM, AT, and WJ. Inflammation was mimicked by a cytokine cocktail, and TLR activation was induced through TLR3 and TLR4 ligation. Osteogenesis was chosen as a model for differentiation. Osteogenic parameters were evaluated by measuring Ca2+ deposits and alkaline phosphatase (ALP) activity at day 7, 14, and 21 of the culture in an osteogenic medium. Our results show that WJ-MSC exhibit a much lower osteogenic potential than the other two MSC types. However, inflammation was able to strongly increase the osteogenic differentiation of WJ-MSC as calcification, and ALP activity appeared as early as day 7. However, this latter enzymatic activity remained much lower than that disclosed by BM-MSC. TLR3 or TLR4 triggering increased the osteogenesis in AT- and, to lesser extent, in BM-MSC. In conclusion, WJ-MSC constitutively disclose a lower osteogenic potential as compared with BM and AT-MSC, which is not affected by TLR triggering but is strongly increased by inflammation, then reaching the level of BM-MSC. These observations suggest that WJ-MSC could constitute an alternative of BM-MSC for bone regenerative applications, as WJ is an easy access source of large amounts of MSC that can effectively differentiate into osteoblasts in an inflammatory setting.

p53 regulates the proliferation, differentiation and spontaneous transformation of mesenchymal stem cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Armesilla-Diaz, Alejandro, E-mail: aarmesilla@cib.csic.es; Elvira, Gema; Silva, Augusto

2009-12-10

Mesenchymal stem cells (MSC) have been extensively studied and gained wide popularity due to their therapeutic potential. Spontaneous transformation of MSC, from both human and murine origin, has been reported in many studies. MSC transformation depends on the culture conditions, the origin of the cells and the time on culture; however, the precise biological characteristics involved in this process have not been fully defined yet. In this study, we investigated the role of p53 in the biology and transformation of murine bone marrow (BM)-derived MSC. We demonstrate that the MSC derived from p53KO mice showed an augmented proliferation rate, amore » shorter doubling time and also morphologic and phenotypic changes, as compared to MSC derived from wild-type animals. Furthermore, the MSC devoid of p53 had an increased number of cells able to generate colonies. In addition, not only proliferation but also MSC differentiation is controlled by p53 since its absence modifies the speed of the process. Moreover, genomic instability, changes in the expression of c-myc and anchorage independent growth were also observed in p53KO MSC. In addition, the absence of p53 implicates the spontaneous transformation of MSC in long-term cultures. Our results reveal that p53 plays a central role in the biology of MSC.« less

Evidence for Transfer of Membranes from Mesenchymal Stem Cells to HL-1 Cardiac Cells.

PubMed

Boomsma, Robert A; Geenen, David L

2014-01-01

This study examined the interaction of mouse bone marrow mesenchymal stem cells (MSC) with cardiac HL-1 cells during coculture by fluorescent dye labeling and then flow cytometry. MSC were layered onto confluent HL-1 cell cultures in a 1 : 4 ratio. MSC gained gap junction permeant calcein from HL-1 cells after 4 hours which was partially reduced by oleamide. After 20 hours, 99% MSC gained calcein, unaffected by oleamide. Double-labeling HL-1 cells with calcein and the membrane dye DiO resulted in transfer of both calcein and DiO to MSC. When HL-1 cells were labeled with calcein and MSC with DiO, MSC gained calcein while HL-1 cells gained DiO. Very little fusion was observed since more than 90% Sca-1 positive MSC gained DiO from HL-1 cells while less than 9% gained gap junction impermeant CMFDA after 20 hours with no Sca-1 transfer to HL-1 cells. Time dependent transfer of membrane DiD was observed from HL-1 cells to MSC (100%) and vice versa (50%) after 20 hours with more limited transfer of CMFDA. These results demonstrate that MSC and HL-1 cells exchange membrane components which may account for some of the beneficial effect of MSC in the heart after myocardial infarction.

Human Umbilical Cord MSC-Derived Exosomes Suppress the Development of CCl4-Induced Liver Injury through Antioxidant Effect.

PubMed

Jiang, Wenqian; Tan, Youwen; Cai, Mengjie; Zhao, Ting; Mao, Fei; Zhang, Xu; Xu, Wenrong; Yan, Zhixin; Qian, Hui; Yan, Yongmin

2018-01-01

Mesenchymal stem cells (MSCs) have been increasingly applied into clinical therapy. Exosomes are small (30-100 nm in diameter) membrane vesicles released by different cell types and possess the similar functions with their derived cells. Human umbilical cord MSC-derived exosomes (hucMSC-Ex) play important roles in liver repair. However, the effects and mechanisms of hucMSC-Ex on liver injury development remain elusive. Mouse models of acute and chronic liver injury and liver tumor were induced by carbon tetrachloride (CCl 4 ) injection, followed by administration of hucMSC-Ex via the tail vein. Alleviation of liver injury by hucMSC-Ex was determined. We further explored the production of oxidative stress and apoptosis in the development of liver injury and compared the antioxidant effects of hucMSC-Ex with frequently used hepatic protectant, bifendate (DDB) in liver injury. hucMSC-Ex alleviated CCl 4 -induced acute liver injury and liver fibrosis and restrained the growth of liver tumors. Decreased oxidative stress and apoptosis were found in hucMSC-Ex-treated mouse models and liver cells. Compared to bifendate (DDB) treatment, hucMSC-Ex presented more distinct antioxidant and hepatoprotective effects. hucMSC-Ex may suppress CCl 4 -induced liver injury development via antioxidant potentials and could be a more effective antioxidant than DDB in CCl 4 -induced liver tumor development.

Novel application of stem cell-derived factors for periodontal regeneration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Inukai, Takeharu, E-mail: t-inukai@med.nagoya-u.ac.jp; Katagiri, Wataru, E-mail: w-kat@med.nagoya-u.ac.jp; Yoshimi, Ryoko, E-mail: lianzi@med.nagoya-u.ac.jp

Highlights: Black-Right-Pointing-Pointer Mesenchymal stem cells (MSCs) secrete a variety of cytokines. Black-Right-Pointing-Pointer Cytokines were detected in conditioned medium from cultured MSCs (MSC-CM). Black-Right-Pointing-Pointer MSC-CM enhanced activation of dog MSCs and periodontal ligament cells. Black-Right-Pointing-Pointer MSC-CM significantly promoted alveolar bone and cementum regeneration. Black-Right-Pointing-Pointer Multiple cytokines contained in MSC-CM promote periodontal regeneration. -- Abstract: The effect of conditioned medium from cultured mesenchymal stem cells (MSC-CM) on periodontal regeneration was evaluated. In vitro, MSC-CM stimulated migration and proliferation of dog MSCs (dMSCs) and dog periodontal ligament cells (dPDLCs). Cytokines such as insulin-like growth factor, vascular endothelial growth factor, transforming growth factor-{beta}1, andmore » hepatocyte growth factor were detected in MSC-CM. In vivo, one-wall critical-size, intrabony periodontal defects were surgically created in the mandible of dogs. Dogs with these defects were divided into three groups that received MSC-CM, PBS, or no implants. Absorbable atelo-collagen sponges (TERUPLUG Registered-Sign ) were used as a scaffold material. Based on radiographic and histological observation 4 weeks after transplantation, the defect sites in the MSC-CM group displayed significantly greater alveolar bone and cementum regeneration than the other groups. These findings suggest that MSC-CM enhanced periodontal regeneration due to multiple cytokines contained in MSC-CM.« less

Analysis of migration rate and chemotaxis of human adipose-derived mesenchymal stem cells in response to LPS and LTA in vitro

DOE Office of Scientific and Technical Information (OSTI.GOV)

Herzmann, Nicole; Salamon, Achim; Fiedler, Tomas

Mesenchymal stem cells (MSC) are able to stimulate the regeneration of injured tissue. Since bacterial infections are common complications in wound healing, bacterial pathogens and their components come into direct contact with MSC. The interaction with bacterial structures influences the proliferation, differentiation and migratory activity of the MSC, which might be of relevance during regeneration. Studies on MSC migration in response to bacterial components have shown different results depending on the cell type. Here, we analyzed the migration rate and chemotaxis of human adipose-derived MSC (adMSC) in response to the basic cell-wall components lipopolysaccharide (LPS) of Gram-negative bacteria and lipoteichoicmore » acid (LTA) of Gram-positive bacteria in vitro. To this end, we used transwell and scratch assays, as well as a specific chemotaxis assay combined with live-cell imaging. We found no significant influence of LPS or LTA on the migration rate of adMSC in transwell or scratch assays. Furthermore, in the µ-slide chemotaxis assay, the stimulation with LPS did not exert any chemotactic effect on adMSC. - Highlights: • LPS increased the release of IL-6 and IL-8 in adMSC significantly. • The migration rate of adMSC was not influenced by LPS or LTA. • LPS or LTA did not exert a chemotactic effect on adMSC.« less

Identification of Intracellular β-Barrel Residues Involved in Ion Selectivity in the Mechanosensitive Channel of Thermoanaerobacter tengcongensis

PubMed Central

Song, Yingcai; Zhang, Bing; Guo, Fei; Yang, Maojun; Li, Yang; Liu, Zhi-Qiang

2017-01-01

The mechanosensitive channel of small conductance (MscS) is a bacterial membrane pore that senses membrane tension and protects cells from lysis by releasing osmolytes. MscS is a homoheptameric channel with a cytoplasmic domain with seven portals and a β-barrel opening to the cytoplasm. TtMscS, an MscS channel from Thermoanaerobacter tengcongensis, is an anion-selective channel. A previous study from our laboratory has defined the crucial role of β-barrel in the anion selectivity of TtMscS (Zhang et al., 2012). However, the mechanistic details by which the β-barrel determines anion selectivity remain unclear. Here, using mutagenesis and patch-clamp recordings, we investigated the function and structural correlations between β-barrels and the anion selectivity of TtMscS at the atomic level. Our results indicated that mutation of V274, a residue at the center of the inner wall of the β-barrel in TtMscS, caused the anion selectivity of TtMscS reverse to cation selectivity. Moreover, the electrostatic potential (T272) and physical size (L276) of residues in the inner wall of β-barrel also determine the anion selectivity of TtMscS. In summary, the present study confirmed that the β-barrel region of TtMscS acts as a “selective filter” that renders TtMscS anion selectivity. PMID:29118717

Blast from pressurized carbon dioxide released into a vented atmospheric chamber

NASA Astrophysics Data System (ADS)

Hansen, P. M.; Gaathaug, A. V.; Bjerketvedt, D.; Vaagsaether, K.

2018-03-01

This study describes the blast from pressurized carbon dioxide (CO2) released from a high-pressure reservoir into an openly vented atmospheric chamber. Small-scale experiments with pure vapor and liquid/vapor mixtures were conducted and compared with simulations. A motivation was to investigate the effects of vent size and liquid content on the peak overpressure and impulse response in the atmospheric chamber. The comparison of vapor-phase CO2 test results with simulations showed good agreement. This numerical code described single-phase gas dynamics inside a closed chamber, but did not model any phase transitions. Hence, the simulations described a vapor-only test into an unvented chamber. Nevertheless, the simulations reproduced the incident shock wave, the shock reflections, and the jet release inside the atmospheric chamber. The rapid phase transition did not contribute to the initial shock strength in the current test geometry. The evaporation rate was too low to contribute to the measured peak overpressure that was in the range of 15-20 kPa. The simulation results produced a calculated peak overpressure of 12 kPa. The liquid tests showed a significantly higher impulse compared to tests with pure vapor. Reducing the vent opening from 0.1 to 0.01 m2 resulted in a slightly higher impulse calculated at 100 ms. The influence of the vent area on the calculated impulse was significant in the vapor-phase tests, but not so clear in the liquid/vapor mixture tests.

Optimizing patient derived mesenchymal stem cells as virus carriers for a Phase I clinical trial in ovarian cancer

PubMed Central

2013-01-01

Background Mesenchymal stem cells (MSC) can serve as carriers to deliver oncolytic measles virus (MV) to ovarian tumors. In preparation for a clinical trial to use MSC as MV carriers, we obtained cells from ovarian cancer patients and evaluated feasibility and safety of this approach. Methods MSC from adipose tissues of healthy donors (hMSC) and nine ovarian cancer patients (ovMSC) were characterized for susceptibility to virus infection and tumor homing abilities. Results Adipose tissue (range 0.16-3.96 grams) from newly diagnosed and recurrent ovarian cancer patients yielded about 7.41×106 cells at passage 1 (range 4–9 days). Phenotype and doubling times of MSC were similar between ovarian patients and healthy controls. The time to harvest of 3.0×108 cells (clinical dose) could be achieved by day 14 (range, 9–17 days). Two of nine samples tested had an abnormal karyotype represented by trisomy 20. Despite receiving up to 1.6×109 MSC/kg, no tumors were seen in SCID beige mice and MSC did not promote the growth of SKOV3 human ovarian cancer cells in mice. The ovMSC migrated towards primary ovarian cancer samples in chemotaxis assays and to ovarian tumors in athymic mice. Using non-invasive SPECT-CT imaging, we saw rapid co-localization, within 5–8 minutes of intraperitoneal administration of MV infected MSC to the ovarian tumors. Importantly, MSC can be pre-infected with MV, stored in liquid nitrogen and thawed on the day of infusion into mice without loss of activity. MV infected MSC, but not virus alone, significantly prolonged the survival of measles immune ovarian cancer bearing animals. Conclusions These studies confirmed the feasibility of using patient derived MSC as carriers for oncolytic MV therapy. We propose an approach where MSC from ovarian cancer patients will be expanded, frozen and validated to ensure compliance with the release criteria. On the treatment day, the cells will be thawed, washed, mixed with virus, briefly centrifuged and incubated for 2 hours with virus prior to infusion of the virus/MSC cocktail into patients. PMID:23347343

Hepatogenic and neurogenic differentiation of bone marrow mesenchymal stem cells from abattoir-derived bovine fetuses

PubMed Central

2014-01-01

Background Mesenchymal stem cells (MSC) are multipotent progenitor cells characterized by their ability to both self-renew and differentiate into tissues of mesodermal origin. The plasticity or transdifferentiation potential of MSC is not limited to mesodermal derivatives, since under appropriate cell culture conditions and stimulation by bioactive factors, MSC have also been differentiated into endodermal (hepatocytes) and neuroectodermal (neurons) cells. The potential of MSC for hepatogenic and neurogenic differentiation has been well documented in different animal models; however, few reports are currently available on large animal models. In the present study we sought to characterize the hepatogenic and neurogenic differentiation and multipotent potential of bovine MSC (bMSC) isolated from bone marrow (BM) of abattoir-derived fetuses. Results Plastic-adherent bMSC isolated from fetal BM maintained a fibroblast-like morphology under monolayer culture conditions. Flow cytometric analysis demonstrated that bMSC populations were positive for MSC markers CD29 and CD73 and pluripotency markers OCT4 and NANOG; whereas, were negative for hematopoietic markers CD34 and CD45. Levels of mRNA of hepatic genes α-fetoprotein (AFP), albumin (ALB), alpha1 antitrypsin (α1AT), connexin 32 (CNX32), tyrosine aminotransferase (TAT) and cytochrome P450 (CYP3A4) were up-regulated in bMSC during a 28-Day period of hepatogenic differentiation. Functional analyses in differentiated bMSC cultures evidenced an increase (P < 0.05) in albumin and urea production and glycogen storage. bMSC cultured under neurogenic conditions expressed NESTIN and MAP2 proteins at 24 h of culture; whereas, at 144 h also expressed TRKA and PrPC. Levels of MAP2 and TRKA mRNA were up-regulated at the end of the differentiation period. Conversely, bMSC expressed lower levels of NANOG mRNA during both hepatogenic and neurogenic differentiation processes. Conclusion The expression patterns of linage-specific markers and the production of functional metabolites support the potential for hepatogenic and neurogenic differentiation of bMSC isolated from BM of abattoir-derived fetuses. The simplicity of isolation and the potential to differentiate into a wide variety of cell lineages lays the foundation for bMSC as an interesting alternative for investigation in MSC biology and eventual applications for regenerative therapy in veterinary medicine. PMID:25011474

Contamination Control Assessment of the World's Largest Space Environment Simulation Chamber

NASA Technical Reports Server (NTRS)

Snyder, Aaron; Henry, Michael W.; Grisnik, Stanley P.; Sinclair, Stephen M.

2012-01-01

The Space Power Facility s thermal vacuum test chamber is the largest chamber in the world capable of providing an environment for space simulation. To improve performance and meet stringent requirements of a wide customer base, significant modifications were made to the vacuum chamber. These include major changes to the vacuum system and numerous enhancements to the chamber s unique polar crane, with a goal of providing high cleanliness levels. The significance of these changes and modifications are discussed in this paper. In addition, the composition and arrangement of the pumping system and its impact on molecular back-streaming are discussed in detail. Molecular contamination measurements obtained with a TQCM and witness wafers during two recent integrated system tests of the chamber are presented and discussed. Finally, a concluding remarks section is presented.

Neuroprotective effects of intravitreally transplanted adipose tissue and bone marrow-derived mesenchymal stem cells in an experimental ocular hypertension model.

PubMed

Emre, Esra; Yüksel, Nurşen; Duruksu, Gökhan; Pirhan, Dilara; Subaşi, Cansu; Erman, Gülay; Karaöz, Erdal

2015-05-01

The purpose of this study was to investigate the neuroprotective effects of bone marrow bone marrow-derived and adipose tissue-derived mesenchymal stromal cells (MSCs) that were intravitreally transplanted in an experimental ocular hypertension (OHT) model. An OHT rat model was generated by means of intracameral injection of hyaluronic acid into the anterior chamber. MSCs labeled with green fluorescence protein were transplanted intravitreally 1 week after OHT induction. At the end of the second and fourth weeks, retinal ganglion cells were visualized with the use of a flat-mount retina method and were evaluated by means of immunofluorescence staining against green fluorescence protein, vimentin, CD105, and cytokines (interleukin [IL]-1Ra, prostaglandin E2 receptor, IL-6, transforming growth factor-β1, interferon-γ and tumor necrosis factor-α). The retinal ganglion cell numbers per area were significantly improved in stem cell-treated OHT groups compared with that in the non-treated OHT group (P < 0.05). The results of immunohistochemical analyses indicated that a limited number of stem cells had integrated into the ganglion cell layer and the inner nuclear layer. The number of cells expressing proinflammatory cytokines (interferon-γ and tumor necrosis factor-α) decreased in the MSC-transferred group compared with that in the OHT group after 4 weeks (P < 0.01). On the other hand, IL-1Ra and prostaglandin E2 receptor expressions were increased in the rat bone marrow-derived MSC group but were more significant in the rat adipose tissue-derived MSC group (P < 0.01). After intravitreal transplantation, MSCs showed a neuroprotective effect in the rat OHT model. Therefore, MSCs promise an alternative therapy approach for functional recovery in the treatment of glaucoma. Copyright © 2015 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

Europlanet Research Infrastructure: Planetary Simulation Facilities

NASA Astrophysics Data System (ADS)

Davies, G. R.; Mason, N. J.; Green, S.; Gómez, F.; Prieto, O.; Helbert, J.; Colangeli, L.; Srama, R.; Grande, M.; Merrison, J.

2008-09-01

EuroPlanet The Europlanet Research Infrastructure consortium funded under FP7 aims to provide the EU Planetary Science community greater access for to research infrastructure. A series of networking and outreach initiatives will be complimented by joint research activities and the formation of three Trans National Access distributed service laboratories (TNA's) to provide a unique and comprehensive set of analogue field sites, laboratory simulation facilities, and extraterrestrial sample analysis tools. Here we report on the infrastructure that comprises the second TNA; Planetary Simulation Facilities. 11 laboratory based facilities are able to recreate the conditions found in the atmospheres and on the surfaces of planetary systems with specific emphasis on Martian, Titan and Europa analogues. The strategy has been to offer some overlap in capabilities to ensure access to the highest number of users and to allow for progressive and efficient development strategies. For example initial testing of mobility capability prior to the step wise development within planetary atmospheres that can be made progressively more hostile through the introduction of extreme temperatures, radiation, wind and dust. Europlanet Research Infrastructure Facilties: Mars atmosphere simulation chambers at VUA and OU These relatively large chambers (up to 1 x 0.5 x 0.5 m) simulate Martian atmospheric conditions and the dual cooling options at VUA allows stabilised instrument temperatures while the remainder of the sample chamber can be varied between 220K and 350K. Researchers can therefore assess analytical protocols for instruments operating on Mars; e.g. effect of pCO2, temperature and material (e.g., ± ice) on spectroscopic and laser ablation techniques while monitoring the performance of detection technologies such as CCD at low T & variable p H2O & pCO2. Titan atmosphere and surface simulation chamber at OU The chamber simulates Titan's atmospheric composition under a range of pressures and temperatures and through provision of external UV light and or electrical discharge can be used to form the well known Titan Aerosol species, which can subsequently be analysed using one of several analytical techniques (UV-Vis, FTIR and mass spectrometry). Simulated surfaces can be produced (icy surfaces down to 15K) and subjected to a variety of light and particles (electron and ion) sources. Chemical and physical changes in the surface may be explored using remote spectroscopy. Planetary Simulation chamber for low density atmospheres INTA-CAB The planetary simulation chamber-ultra-high vacuum equipment (PSC-UHV) has been designed to study planetary surfaces and low dense atmospheres, space environments or any other hypothetic environment at UHV. Total pressure ranges from 7 mbar (Martian conditions) to 5x10-9 mbar. A residual gas analyzer regulates gas compositions to ppm precision. Temperature ranges from 4K to 325K and most operations are computer controlled. Radiation levels are simulated using a deuterium UV lamp, and ionization sources. 5 KV electron and noble-gas discharge UV allows measurement of IR and UV spectra and chemical compositions are determined by mass spectroscopy. Planetary Simulation chamber for high density planetary atmospheres at INTA-CAB The facility allows experimental study of planetary environments under high pressure, and was designed to include underground, seafloor and dense atmosphere environments. Analytical capabilities include Raman spectra, physicochemical properties of materials, e.a. thermal conductivity. P-T can be controlled as independent variables to allow monitoring of the tolerance of microorganisms and the stability of materials and their phase changes. Planetary Simulation chamber for icy surfaces at INTA-CAB This chamber is being developed to the growth of ice samples to simulate the chemical and physical properties of ices found on both planetary bodies and their moons. The goal is to allow measurement of the physical properties of ice samples formed under planetary conditions to assess how rheology varies with pressure and temperature and grain size to gain a far better understanding of how tectonics may operate on icy moons. Hot planetary surfaces simulation chamber at DLR The planetary simulation chamber is to study the behaviour of planetary analogue materials on the surface of hot (airless) bodies in the solar system. Samples can be heated up to temperatures of 500°C simulating conditions found on the surface of Mercury and Venus. This enables highly accurate thermal emission measurements using the integrated infrared spectrometer and calibrated sources. Thermal gradients can be applied to samples to simulate diurnal thermal cycles and examine thermal stresses in materials. The chamber can be placed under vacuum or purged with gas. In addition, to the high temperature chamber a number of further planetary simulation chambers are available equipped with LIBS and Raman-spectroscopy equipment. Dust analogue simulation chamber at INAF/OACN This facility produces and characterises dust analogues (arc discharge, laser ablation, grinding of minerals, ices) in a variety of simulation chambers under variable pressure (10-6 - 10-3 mbar), temperature (80 - 330 K) and gas composition. Dust and analogues are characterised by a variety of Spectroscopic (absorption, transmission, diffuse-specular reflectance) and imaging techniques (SEM) and can be subjected to thermal annealing, ion bombardment and UV irradiation. Dust accelerator facility at Max Planck Institüt Nuclear Physics, Heidelberg. This facility allows the investigation of hypervelocity dust impacts onto various materials. Dust grain materials from nano to micron sizes are accelerated using a 2 MV Vande- Graaff to velocities between 1 and 60 km/s comparable to the planetary rings of the giant gas planets and impact ejecta processes on the surface of small bodies (asteroids, comets) as well as moons and planetary surfaces. Potential phenomena for study include dust charging, dust magentosphere interactions, dust impact flashes and the possibility of obtaining compositional measurements of impact plasma plumes. Mars surface simulation Laboratory, Aberystwyth University. A Planetary Analogue Terrain Laboratory facilitates comprehensive mission operations emulation experiments designed to interpret and maximise scientific data return from robotic instruments. This facility includes Mars Soil Simulant and `science target' rocks that have been fully characterised. The terrain also has an area for sub-surface sampling. An Access Grid Node allows simulation of remote control operation and diminishes the need for direct onsite attendance. PAT Lab has a large selection of software tools for rover, robot arm and instrument modelling and simulation, and for the processing and visualisation of captured instrument data. Instrument motion is measured using a Vicon motion capture system with a resolution < 0.1 mm. Dusty wind tunnel at Aarhus University, Denmark The Aarhus wind tunnel simulates wind driven dust exposure on Mars. This allows study into analogue materials, dust/surface processes, meteorological condition and microbiological survival under Martian conditions. The multipurpose facility is used to quantify dust deposition (i.e. on optical surfaces, electrical or mechanical components) and examine the operation of instrumentation in dusty/windy environment under Martian conditions (pressure, gas composition & temperature). This includes calibration of wind flow instrumentation and dust sensors.

Atlas-Centaur Separation Test in the Space Power Chambers

NASA Image and Video Library

1963-11-21

An Atlas/Centaur mass model undergoes a separation test inside the Space Power Chambers at NASA Lewis Research Center. Lewis was in the midst of an extensive effort to prepare the Centaur second-stage rocket for its missions to send the Surveyor spacecraft to the moon as a precursor to the Apollo missions. As part of these preparations, Lewis management decided to convert its Altitude Wind Tunnel into two large test chambers—the Space Power Chambers. The conversion included the removal of the tunnel’s internal components and the insertion of bulkheads to seal off the new chambers within the tunnel. One chamber could simulate conditions found at 100 miles altitude, while this larger chamber simulated the upper atmosphere. In this test series, researchers wanted to verify that the vehicle’s retrorockets would properly separate the Centaur from the Atlas. The model was suspended horizontally on a trolley system inside chamber. A net was hung at one end to catch the jettisoned Atlas model. The chamber atmosphere was reduced to a pressure altitude of 100,000 feet, and high-speed cameras were synchronized to the ignition of the retrorockets. The simulated Centaur is seen here jettisoning from the Atlas out of view to the right. The study resulted in a new jettison method that would significantly reduce the separation time and thus minimize the danger of collision between the two stages during separation.

Engineering mesenchymal stem cells for regenerative medicine and drug delivery.

PubMed

Park, Ji Sun; Suryaprakash, Smruthi; Lao, Yeh-Hsing; Leong, Kam W

2015-08-01

Researchers have applied mesenchymal stem cells (MSC) to a variety of therapeutic scenarios by harnessing their multipotent, regenerative, and immunosuppressive properties with tropisms toward inflamed, hypoxic, and cancerous sites. Although MSC-based therapies have been shown to be safe and effective to a certain degree, the efficacy remains low in most cases when MSC are applied alone. To enhance their therapeutic efficacy, researchers have equipped MSC with targeted delivery functions using genetic engineering, therapeutic agent incorporation, and cell surface modification. MSC can be genetically modified virally or non-virally to overexpress therapeutic proteins that complement their innate properties. MSC can also be primed with non-peptidic drugs or magnetic nanoparticles for enhanced efficacy and externally regulated targeting, respectively. Furthermore, MSC can be functionalized with targeting moieties to augment their homing toward therapeutic sites using enzymatic modification, chemical conjugation, or non-covalent interactions. These engineering techniques are still works in progress, requiring optimization to improve the therapeutic efficacy and targeting effectiveness while minimizing any loss of MSC function. In this review, we will highlight the advanced techniques of engineering MSC, describe their promise and the challenges of translation into clinical settings, and suggest future perspectives on realizing their full potential for MSC-based therapy. Copyright © 2015 Elsevier Inc. All rights reserved.

OVERALL MASS TRANSFER COEFFICIENT FOR POLLUTANT EMISSIONS FROM SMALL WATER POOLS UNDER SIMULATED INDOOR ENVIRONMENTAL CONDITIONS

EPA Science Inventory

Small chamber tests were conducted to experimentally determine the overall mass transfer coefficient for pollutant emissions from still water under simulated indoor-residential or occupational-environmental conditions. Fourteen tests were conducted in small environmental chambers...

Msc1 acts through histone H2A.Z to promote chromosome stability in Schizosaccharomyces pombe.

PubMed

Ahmed, Shakil; Dul, Barbara; Qiu, Xinxing; Walworth, Nancy C

2007-11-01

As a central component of the DNA damage checkpoint pathway, the conserved protein kinase Chk1 mediates cell cycle progression when DNA damage is generated. Msc1 was identified as a multicopy suppressor capable of facilitating survival in response to DNA damage of cells mutant for chk1. We demonstrate that loss of msc1 function results in an increased rate of chromosome loss and that an msc1 null allele exhibits genetic interactions with mutants in key kinetochore components. Multicopy expression of msc1 robustly suppresses a temperature-sensitive mutant (cnp1-1) in the centromere-specific histone H3 variant CENP-A, and localization of CENP-A to the centromere is compromised in msc1 null cells. We present several lines of evidence to suggest that Msc1 carries out its function through the histone H2A variant H2A.Z, encoded by pht1 in fission yeast. Like an msc1 mutant, a pht1 mutant also exhibits chromosome instability and genetic interactions with kinetochore mutants. Suppression of cnp1-1 by multicopy msc1 requires pht1. Likewise, suppression of the DNA damage sensitivity of a chk1 mutant by multicopy msc1 also requires pht1. We present the first genetic evidence that histone H2A.Z may participate in centromere function in fission yeast and propose that Msc1 acts through H2A.Z to promote chromosome stability and cell survival following DNA damage.

Msc1 Acts Through Histone H2A.Z to Promote Chromosome Stability in Schizosaccharomyces pombe

PubMed Central

Ahmed, Shakil; Dul, Barbara; Qiu, Xinxing; Walworth, Nancy C.

2007-01-01

As a central component of the DNA damage checkpoint pathway, the conserved protein kinase Chk1 mediates cell cycle progression when DNA damage is generated. Msc1 was identified as a multicopy suppressor capable of facilitating survival in response to DNA damage of cells mutant for chk1. We demonstrate that loss of msc1 function results in an increased rate of chromosome loss and that an msc1 null allele exhibits genetic interactions with mutants in key kinetochore components. Multicopy expression of msc1 robustly suppresses a temperature-sensitive mutant (cnp1-1) in the centromere-specific histone H3 variant CENP-A, and localization of CENP-A to the centromere is compromised in msc1 null cells. We present several lines of evidence to suggest that Msc1 carries out its function through the histone H2A variant H2A.Z, encoded by pht1 in fission yeast. Like an msc1 mutant, a pht1 mutant also exhibits chromosome instability and genetic interactions with kinetochore mutants. Suppression of cnp1-1 by multicopy msc1 requires pht1. Likewise, suppression of the DNA damage sensitivity of a chk1 mutant by multicopy msc1 also requires pht1. We present the first genetic evidence that histone H2A.Z may participate in centromere function in fission yeast and propose that Msc1 acts through H2A.Z to promote chromosome stability and cell survival following DNA damage. PMID:17947424

Avoidance of Maternal Cell Contamination and Overgrowth in Isolating Fetal Chorionic Villi Mesenchymal Stem Cells from Human Term Placenta

PubMed Central

Sardesai, Varda S.; Shafiee, Abbas; Fisk, Nicholas M.

2017-01-01

Abstract Human placenta is rich in mesenchymal stem/stromal cells (MSC), with their origin widely presumed fetal. Cultured placental MSCs are confounded by a high frequency of maternal cell contamination. Our recent systematic review concluded that only a small minority of placental MSC publications report fetal/maternal origin, and failed to discern a specific methodology for isolation of fetal MSC from term villi. We determined isolation conditions to yield fetal and separately maternal MSC during ex vivo expansion from human term placenta. MSCs were isolated via a range of methods in combination; selection from various chorionic regions, different commercial media, mononuclear cell digest and/or explant culture. Fetal and maternal cell identities were quantitated in gender‐discordant pregnancies by XY chromosome fluorescence in situ hybridization. We first demonstrated reproducible maternal cell contamination in MSC cultures from all chorionic anatomical locations tested. Cultures in standard media rapidly became composed entirely of maternal cells despite isolation from fetal villi. To isolate pure fetal cells, we validated a novel isolation procedure comprising focal dissection from the cotyledonary core, collagenase/dispase digestion and explant culture in endothelial growth media that selected, and provided a proliferative environment, for fetal MSC. Comparison of MSC populations within the same placenta confirmed fetal to be smaller, more osteogenic and proliferative than maternal MSC. We conclude that in standard media, fetal chorionic villi‐derived MSC (CV‐MSC) do not grow readily, whereas maternal MSC proliferate to result in maternal overgrowth during culture. Instead, fetal CV‐MSCs require isolation under specific conditions, which has implications for clinical trials using placental MSC. Stem Cells Translational Medicine 2017;6:1070–1084 PMID:28205414

Mesenchymal stem cells induce epithelial proliferation within the inflamed stomach.

PubMed

Donnelly, Jessica M; Engevik, Amy; Feng, Rui; Xiao, Chang; Boivin, Gregory P; Li, Jing; Houghton, JeanMarie; Zavros, Yana

2014-06-15

Bone marrow-derived mesenchymal stem cells (MSCs) sustain cancer cells by creating a microenvironment favorable for tumor growth. In particular, MSCs have been implicated in gastric cancer development. There is extensive evidence suggesting that Hedgehog signaling regulates tumor growth. However, very little is known regarding the precise roles of Hedgehog signaling and MSCs in tumor development within the stomach. The current study tests that hypothesis that Sonic Hedgehog (Shh), secreted from MSCs, provides a proliferative stimulus for the gastric epithelium in the presence of inflammation. Red fluorescent protein-expressing MSCs transformed in vitro (stMSCs) were transduced with lentiviral constructs containing a vector control (stMSC(vect)) or short hairpin RNA (shRNA) targeting the Shh gene (stMSC(ShhKO)). Gastric submucosal transplantation of wild-type MSCs (wtMSCs), wild-type MSCs overexpressing Shh (wtMSC(Shh)), stMSC(vect), or stMSC(ShhKO) cells in C57BL/6 control (BL/6) or gastrin-deficient (GKO) mice was performed and mice analyzed 30 and 60 days posttransplantation. Compared with BL/6 mice transplanted with wtMSC(Shh) and stMSC(vect) cells, inflamed GKO mice developed aggressive gastric tumors. Tumor development was not observed in mouse stomachs transplanted with wtMSC or stMSC(ShhKO) cells. Compared with stMSC(ShhKO)-transplanted mice, within the inflamed GKO mouse stomach, Shh-expressing stMSC(vect)- and wtMSC(Shh)-induced proliferation of CD44-positive cells. CD44-positive cells clustered in gland-like structures within the tumor stroma and were positive for Patched (Ptch) expression. We conclude that Shh, secreted from MSCs, provides a proliferative stimulus for the gastric epithelium that is associated with tumor development, a response that is sustained by chronic inflammation. Copyright © 2014 the American Physiological Society.

Targeting Murine Mesenchymal Stem Cells to Kidney Injury Molecule‐1 Improves Their Therapeutic Efficacy in Chronic Ischemic Kidney Injury

PubMed Central

Zou, Xiangyu; Jiang, Kai; Puranik, Amrutesh S.; Jordan, Kyra L.; Tang, Hui

2018-01-01

Abstract Mesenchymal stem cells (MSC) have been experimentally used for kidney repair, but modest retention limits their efficacy. Cell‐surface coating allows modulating MSC homing and interaction with target cells. We coated mouse adipose tissue‐derived MSC with antibodies directed against kidney injury molecule‐1 (ab‐KIM1), which is upregulated in injured kidneys, and tested the hypothesis that this would enhance their therapeutic effects in ischemic kidney injury. Untreated MSC, ab‐KIM1‐coated MSC (KIM‐MSC), or vehicle, were injected systemically into the carotid artery of 2‐kidneys, 1‐clip mice 2 weeks after surgery. MSC retention in different organs was explored 24 hours, 48 hours, or 2 weeks after injection. Renal volume, perfusion, and oxygenation were studied 2 weeks after injection using magnetic resonance imaging in vivo, and renal inflammation, apoptosis, capillary density, and fibrosis ex vivo. The ab‐KIM1 coating had little effect on MSC viability or proliferation. The stenotic kidney showed upregulated KIM1 expression, selective homing, and greater retention of KIM‐MSC compared to untreated MSC and compared to other organs. KIM‐MSC‐injected mice improved renal perfusion and capillary density, and attenuated oxidative damage, apoptosis, and fibrosis compared to mice treated with vehicle or with native MSC. In conclusion, MSC coating with ab‐KIM1 increased their retention in the ischemic kidney and enhanced their therapeutic efficacy. This novel method may be useful to selectively target injured kidneys, and supports further development of strategies to enhance cell‐based treatment of ischemic kidney injury. Stem Cells Translational Medicine 2018;7:394–403 PMID:29446551

Exosomes of human placenta-derived mesenchymal stem cells stimulate angiogenesis.

PubMed

Komaki, Motohiro; Numata, Yuri; Morioka, Chikako; Honda, Izumi; Tooi, Masayuki; Yokoyama, Naoki; Ayame, Hirohito; Iwasaki, Kengo; Taki, Atsuko; Oshima, Noriko; Morita, Ikuo

2017-10-03

The therapeutic potential of mesenchymal stem cells (MSCs) may be attributed partly to humoral factors such as growth factors, cytokines, and chemokines. Human term placental tissue-derived MSCs (PlaMSCs), or conditioned medium left over from cultures of these cells, have been reported to enhance angiogenesis. Recently, the exosome, which can transport a diverse suite of macromolecules, has gained attention as a novel intercellular communication tool. However, the potential role of the exosome in PlaMSC therapeutic action is not well understood. The purpose of this study was to evaluate PlaMSC-derived exosome angiogenesis promotion in vitro and in vivo. MSCs were isolated from human term placental tissue by enzymatic digestion. Conditioned medium was collected after 48-h incubation in serum-free medium (PlaMSC-CM). Angiogenic factors present in PlaMSC-CM were screened by a growth factor array. Exosomes were prepared by ultracentrifugation of PlaMSC-CM, and confirmed by transmission electron microscopy, dynamic light scattering, and western blot analyses. The proangiogenic activity of PlaMSC-derived exosomes (PlaMSC-exo) was assessed using an endothelial tube formation assay, a cell migration assay, and reverse transcription-PCR analysis. The in-vivo angiogenic activity of PlaMSC-exo was evaluated using a murine auricle ischemic injury model. PlaMSC-CM contained both angiogenic and angiostatic factors, which enhanced endothelial tube formation. PlaMSC-exo were incorporated into endothelial cells; these exosomes stimulated both endothelial tube formation and migration, and enhanced angiogenesis-related gene expression. Laser Doppler blood flow analysis showed that PlaMSC-exo infusion also enhanced angiogenesis in an in-vivo murine auricle ischemic injury model. PlaMSC-exo enhanced angiogenesis in vitro and in vivo, suggesting that exosomes play a role in the proangiogenic activity of PlaMSCs. PlaMSC-exo may be a novel therapeutic approach for treating ischemic diseases.

Mesenchymal stem cells ameliorate podocyte injury and proteinuria in a type 1 diabetic nephropathy rat model.

PubMed

Wang, Shuai; Li, Yi; Zhao, Jinghong; Zhang, Jingbo; Huang, Yunjian

2013-04-01

Mesenchymal stem cells (MSC) attenuate albuminuria and preserve normal renal histology in diabetic mice. However, the effects of MSC on glomerular podocyte injury remain uncertain. The aim of this study was to evaluate the effects of MSC on podocyte injury in streptozotocin (STZ)-induced diabetic rats. Thirty days after diabetes induction by STZ injection (65 mg/kg, intraperitoneally) in Sprague-Dawley rats, the diabetic rats received medium or 2 × 10(6) enhanced green fluorescent protein-labeled MSC via the renal artery. In vivo tracking of MSC was followed by immunofluorescence analysis. Diabetes-related physical and biochemical parameters were measured on day 60 after the MSC infusion. The expression of podocyte markers (nephrin and podocin), podocyte survival factors (VEGF and BMP-7), and the ultrastructural pathology of podocytes were also assessed. MSC were only detected in the glomeruli from the left kidney receiving MSC infusion. Compared with medium-treated diabetic rats, rats treated with MSC showed a suppressed increase in kidney weight, kidney to body weight index, creatinine clearance rate, and urinary albumin to creatinine ratio; however, the treatment had no effect on blood glucose or body weight levels. Furthermore, the MSC treatment reduced the loss of podocytes, effacement of foot processes, widening of foot processes, thickening of glomerular basal membrane (GBM), and loss of glomerular nephrin and podocin. Most important, MSC-injected kidneys expressed higher levels of BMP-7 but not of VEGF. Our results clearly demonstrated that intra-arterial administration of MSC prevented the development of albuminuria as well as any damage to or loss of podocytes, though there was no improvement in blood sugar levels. The protective effects of MSC may be mediated in part by increasing BMP-7 secretion. Copyright © 2013 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.

DSP30 enhances the immunosuppressive properties of mesenchymal stromal cells and protects their suppressive potential from lipopolysaccharide effects: A potential role of adenosine.

PubMed

Sangiorgi, Bruno; De Freitas, Helder Teixeira; Schiavinato, Josiane Lilian Dos Santos; Leão, Vitor; Haddad, Rodrigo; Orellana, Maristela Delgado; Faça, Vitor Marcel; Ferreira, Germano Aguiar; Covas, Dimas Tadeu; Zago, Marco Antônio; Panepucci, Rodrigo Alexandre

2016-07-01

Multipotent mesenchymal stromal cells (MSC) are imbued with an immunosuppressive phenotype that extends to several immune system cells. In this study, we evaluated how distinct Toll-like receptor (TLR) agonists impact immunosuppressive properties of bone marrow (BM)-MSC and explored the potential mechanisms involved. We show that TLR4 stimulation by lipopolysaccharide (LPS) restricted the ability of MSC to suppress the proliferation of T lymphocytes, increasing the gene expression of interleukin (IL)-1β and IL-6. In contrast, stimulation of TLR9 by DSP30 induced proliferation and the suppressive potential of BM-MSC, coinciding with reducing tumor necrosis factor (TNF)-α expression, increased expression of transforming growth factor (TGF)-β1, increased percentages of BM-MSC double positive for the ectonucleotidases CD39+CD73+ and adenosine levels. Importantly, following simultaneous stimulation with LPS and DSP30, BM-MSC's ability to suppress T lymphocyte proliferation was comparable with that of non-stimulated BM-MSC levels. Moreover, stimulation of BM-MSC with LPS reduced significantly the gene expression levels, on co-cultured T lymphocyte, of IL-10 and interferon (IFN)γ, a cytokine with potential to enhance the immunosuppression mediated by MSC and ameliorate the clinical outcome of patients with graft-versus-host disease (GVHD). Altogether, our findings reiterate the harmful effects of LPS on MSC immunosuppression, besides indicating that DSP30 could provide a protective effect against LPS circulating in the blood of GVHD patients who receive BM-MSC infusions, ensuring a more predictable immunosuppressive effect. The novel effects and potential mechanisms following the stimulation of BM-MSC by DSP30 might impact their clinical use, by allowing the derivation of optimal "licensing" protocols for obtaining therapeutically efficient MSC. Copyright © 2016 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

CHAMBER SIMULATION OF FINE PARTICLE PENETRATION INTO HOUSES

EPA Science Inventory

the paper discusses chamber simulation of fine particle penetration into houses. (NOTE: A number of recent studies have shown a correlation of negative health effects with increases in outdoor fine particles. Since people spend up to 90% of their time indoors, the relationship be...

[Experimental study on dog's bone marrow stem cells transfected by pIRES2-EGFP-IGF-1 gene].

PubMed

Zhu, Guo-qiang; Wu, Zhi-fen; Li, Yuan-fei; Hu, De-hua; Wang, Qin-tao

2006-12-01

To establish the bone marrow stem cells (MSC) model which could highly express the insulin-like growth factor 1 (IGF-1) transfected by dog's IGF-1 gene. pIRES2-EGFP-IGF-1 was transfected into MSC by lipofectamine. Positive clones were selected with G418. The expression of IGF-1 protein in the MSC was determined by immunohistochemistry and Western blot analysis. The IGF-1 in the supernatant of the transfected MSC was detected by sandwich-in ELISA. The periodontal ligament cells (PDLC) were cultured in the supernatant of the transfected MSC. The changes of PDLC' proliferation were observed by MTT. IGF-1-transfected MSC could apparently express IGF-1. The IGF-1 protein in the supernatant of the transfected MSC was confirmed by sandwich-in ELISA. IGF-1 could promote the PDLC' proliferation. The MSC transfected by dog's IGF-1 gene can highly express IGF-1, which may lay the foundation for further study on periodontal regeneration.

[Construction of fetal mesenchymal stem cell cDNA subtractive library].

PubMed

Yang, Li; Wang, Dong-Mei; Li, Liang; Bai, Ci-Xian; Cao, Hua; Li, Ting-Yu; Pei, Xue-Tao

2002-04-01

To identify differentially expressed genes between fetal mesenchymal stem cell (MSC) and adult MSC, especially specified genes expressed in fetal MSC, a cDNA subtractive library of fetal MSC was constructed using suppression subtractive hybridization (SSH) technique. At first, total RNA was isolated from fetal and adult MSC. Using SMART PCR synthesis method, single-strand and double-strand cDNAs were synthesized. After Rsa I digestion, fetal MSC cDNAs were divided into two groups and ligated to adaptor 1 and adaptor 2 respectively. Results showed that the amplified library contains 890 clones. Analysis of 890 clones with PCR demonstrated that 768 clones were positive. The positive rate is 86.3%. The size of inserted fragments in these positive clones was between 0.2 - 1 kb, with an average of 400 - 600 bp. SSH is a convenient and effective method for screening differentially expressed genes. The constructed cDNA subtractive library of fetal MSC cDNA lays solid foundation for screening and cloning new and specific function related genes of fetal MSC.

Auto-transplanted mesenchymal stromal cell fate in periodontal tissue of beagle dogs.

PubMed

Wei, Na; Gong, Ping; Liao, Dapeng; Yang, Xingmei; Li, Xiaoyu; Liu, Yurong; Yuan, Quan; Tan, Zhen

2010-07-01

Mesenchymal stromal cells (MSC) possess multilineage differentiation potential and characteristics of self-renewal. It has been reported that MSC can acquire characteristics of cells in the periodontal ligament (PDL) in vitro. Moreover, the transplantation of MSC has been shown to be a promising strategy for treating periodontal defects. However, little is known about the fate of MSC in periodontal tissue in vivo. The aim of this study was to trace the paths of MSC after transplantation into periodontal tissues in vivo. MSC labeled with bromodeoxyuridine (BrdU) were transplanted into periodontal defects of beagle dogs. Six weeks after surgery, the animals were killed and decalcified specimens were prepared. Migration and differentiation of MSC were detected by single/double immunohistochemistry and a combination of immunohistochemistry and in situ hybridization. BrdU-labeled MSC were observed distributing into periodontal tissue that included alveolar bone, PDL, cementum and blood vessels and expressing surface markers typical of osteoblasts and fibroblasts. Cumulatively, our data suggest that MSC migrate throughout periodontal tissue and differentiate into osteoblasts and fibroblasts after transplantation into periodontal defects at 6 weeks in vivo, and have the potential to regenerate periodontal tissue.

Hepatocyte Growth Factor Is Required for Mesenchymal Stromal Cell Protection Against Bleomycin-Induced Pulmonary Fibrosis

PubMed Central

Cahill, Emer F.; Kennelly, Helen; Carty, Fiona; Mahon, Bernard P.

2016-01-01

The incidence of idiopathic pulmonary fibrosis is on the rise and existing treatments have failed to halt or reverse disease progression. Mesenchymal stromal cells (MSCs) have potent cytoprotective effects, can promote tissue repair, and have demonstrated efficacy in a range of fibrotic lung diseases; however, the exact mechanisms of action remain to be elucidated. Chemical antagonists and short hairpin RNA knockdown were used to identify the mechanisms of action used by MSCs in promoting wound healing, proliferation, and inhibiting apoptosis. Using the bleomycin induced fibrosis model, the protective effects of early or late MSC administration were examined. The role for hepatocyte growth factor (HGF) in MSC protection against bleomycin lung injury was examined using HGF knockdown MSC. Terminal deoxynucleotidyl transferase (TdT) dUTP nick-end labeling assay was performed on ex vivo lung sections to examine the effects of MSC on apoptosis. MSC conditioned media (CM) enhanced wound closure and inhibited apoptosis of pulmonary cells in vitro. HGF was required for MSC CM enhancement of epithelial cell proliferation and inhibition of apoptosis. In contrast, MSC required COX-2 for CM to inhibit fibroblast proliferation. In a murine model, early administration of MSC protected against bleomycin induced lung fibrosis and correlated with reduced levels of the proinflammatory cytokine interleukin-1β, reduced levels of apoptosis, and significantly increased levels of HGF. These protective effects were in part mediated by MSC derived HGF as HGF knockdown MSC were unable to protect against fibrosis in vivo. These findings delineate the mechanisms of MSC protection in a preclinical model of fibrotic lung disease. Significance The mechanisms used by mesenchymal stromal cells (MSCs) in mediating protective effects in chronic models of lung disease are not understood and remain to be elucidated. These findings from in vitro studies highlight an important role for the MSC-derived soluble factors hepatocyte growth factor (HGF) and prostaglandin E2 in promoting wound healing and inhibiting apoptosis. Furthermore, this study translates these findings demonstrating an important role for HGF in the protective effects mediated by MSC in vivo in the bleomycin model. These findings support a targeted approach to enhancing MSC therapy for fibrotic disease and highlight the importance of timing of MSC therapy. PMID:27388243

Geometric optimization of microreactor chambers to increase the homogeneity of the velocity field

NASA Astrophysics Data System (ADS)

Pálovics, Péter; Ender, Ferenc; Rencz, Márta

2018-06-01

In this work microfluidic flow-through chambers are investigated. They are filled with magnetic nanoparticle (MNP) suspension in order to facilitate enzymatic reactions. The enzyme is immobilized on the surface of the MNPs. These reactions have been found to be flow rate dependent. To overcome this issue various chamber geometries have been examined and optimized geometries have been designed and tested experimentally. The investigation is supported with dedicated CFD simulations using the open source software OpenFOAM. The paper presents the theoretical background and the results of the simulations. The simulations have been verified with measurements and these too are presented in the paper.

Experimental and simulation study of a Gaseous oxygen/Gaseous hydrogen vortex cooling thrust chamber

NASA Astrophysics Data System (ADS)

Yu, Nanjia; Zhao, Bo; Li, Gongnan; Wang, Jue

2016-01-01

In this paper, RNG k-ε turbulence model and PDF non-premixed combustion model are used to simulate the influence of the diameter of the ring of hydrogen injectors and oxidizer-to-fuel ratio on the specific impulse of the vortex cooling thrust chamber. The simulation results and the experimental tests of a 2000 N Gaseous oxygen/Gaseous hydrogen vortex cooling thrust chamber reveal that the efficiency of the specific impulse improves significantly with increasing of the diameter of the ring of hydrogen injectors. Moreover, the optimum efficiency of the specific impulse is obtained when the oxidizer-to-fuel ratio is near the stoichiometric ratio.

Three-dimensional numerical simulation of a continuously rotating detonation in the annular combustion chamber with a wide gap and separate delivery of fuel and oxidizer

NASA Astrophysics Data System (ADS)

Frolov, S. M.; Dubrovskii, A. V.; Ivanov, V. S.

2016-07-01

The possibility of integrating the Continuous Detonation Chamber (CDC) in a gas turbine engine (GTE) is demonstrated by means of three-dimensional (3D) numerical simulations, i. e., the feasibility of the operation process in the annular combustion chamber with a wide gap and with separate feeding of fuel (hydrogen) and oxidizer (air) is proved computationally. The CDC with an upstream isolator damping pressure disturbances propagating towards the compressor is shown to exhibit a gain in the total pressure of 15% as compared with the same combustion chamber operating in the deflagration mode.

In-Situ Bioreduction and Removal of Ammonium Perchlorate

DTIC Science & Technology

2006-05-09

Ader, PhD. Max Coleman, PhD. Swades Chaudhuri, PhD. Susan O’Connor MSc, MSc Royce Bruce, MSc. Urania Michaelidou, MSc. Melissa Rice, MSc. Sarah...1993. SeqApp, 1.9a157 ed. Biocomputing Office, Biology Dept., Indiana University, Bloomington, IN. 44. Giordano , G., L. Saracino, and L. Grillet. 1985...Mutant of E. coli K-12. Biocimica et Biophysica Acta 839:181-190. 45. Guigliarelli, B., A. Magalon, M. Asso, P. Bertrand, C. Frixon, G. Giordano

Characterization and Simulation of a New Design Parallel-Plate Ionization Chamber for CT Dosimetry at Calibration Laboratories

NASA Astrophysics Data System (ADS)

Perini, Ana P.; Neves, Lucio P.; Maia, Ana F.; Caldas, Linda V. E.

2013-12-01

In this work, a new extended-length parallel-plate ionization chamber was tested in the standard radiation qualities for computed tomography established according to the half-value layers defined at the IEC 61267 standard, at the Calibration Laboratory of the Instituto de Pesquisas Energéticas e Nucleares (IPEN). The experimental characterization was made following the IEC 61674 standard recommendations. The experimental results obtained with the ionization chamber studied in this work were compared to those obtained with a commercial pencil ionization chamber, showing a good agreement. With the use of the PENELOPE Monte Carlo code, simulations were undertaken to evaluate the influence of the cables, insulator, PMMA body, collecting electrode, guard ring, screws, as well as different materials and geometrical arrangements, on the energy deposited on the ionization chamber sensitive volume. The maximum influence observed was 13.3% for the collecting electrode, and regarding the use of different materials and design, the substitutions showed that the original project presented the most suitable configuration. The experimental and simulated results obtained in this work show that this ionization chamber has appropriate characteristics to be used at calibration laboratories, for dosimetry in standard computed tomography and diagnostic radiology quality beams.

Human mesenchymal stromal cell-secreted lactate induces M2-macrophage differentiation by metabolic reprogramming

PubMed Central

Civini, Sara; Pacelli, Consiglia; Dieng, Mame Massar; Lemieux, William; Jin, Ping; Bazin, Renée; Patey, Natacha; Marincola, Francesco M.; Moldovan, Florina; Zaouter, Charlotte; Trudeau, Louis-Eric; Benabdhalla, Basma; Louis, Isabelle; Beauséjour, Christian; Stroncek, David; Le Deist, Françoise; Haddad, Elie

2016-01-01

Human mesenchymal stromal cells (MSC) have been shown to dampen immune response and promote tissue repair, but the underlying mechanisms are still under investigation. Herein, we demonstrate that umbilical cord-derived MSC (UC-MSC) alter the phenotype and function of monocyte-derived dendritic cells (DC) through lactate-mediated metabolic reprogramming. UC-MSC can secrete large quantities of lactate and, when present during monocyte-to-DC differentiation, induce instead the acquisition of M2-macrophage features in terms of morphology, surface markers, migratory properties and antigen presentation capacity. Microarray expression profiling indicates that UC-MSC modify the expression of metabolic-related genes and induce a M2-macrophage expression signature. Importantly, monocyte-derived DC obtained in presence of UC-MSC, polarize naïve allogeneic CD4+ T-cells into Th2 cells. Treatment of UC-MSC with an inhibitor of lactate dehydrogenase strongly decreases lactate concentration in culture supernatant and abrogates the effect on monocyte-to-DC differentiation. Metabolic analysis further revealed that UC-MSC decrease oxidative phosphorylation in differentiating monocytes while strongly increasing the spare respiratory capacity proportional to the amount of secreted lactate. Because both MSC and monocytes are recruited in vivo at the site of tissue damage and inflammation, we propose the local increase of lactate concentration induced by UC-MSC and the consequent enrichment in M2-macrophage generation as a mechanism to achieve immunomodulation. PMID:27070086

Safety and immune regulatory properties of canine induced pluripotent stem cell-derived mesenchymal stem cells.

PubMed

Chow, Lyndah; Johnson, Valerie; Regan, Dan; Wheat, William; Webb, Saiphone; Koch, Peter; Dow, Steven

2017-12-01

Mesenchymal stem cells (MSCs) exhibit broad immune modulatory activity in vivo and can suppress T cell proliferation and dendritic cell activation in vitro. Currently, most MSC for clinical usage are derived from younger donors, due to ease of procurement and to the superior immune modulatory activity. However, the use of MSC from multiple unrelated donors makes it difficult to standardize study results and compare outcomes between different clinical trials. One solution is the use of MSC derived from induced pluripotent stem cells (iPSC); as iPSC-derived MSC have nearly unlimited proliferative potential and exhibit in vitro phenotypic stability. Given the value of dogs as a spontaneous disease model for pre-clinical evaluation of stem cell therapeutics, we investigated the functional properties of canine iPSC-derived MSC (iMSC), including immune modulatory properties and potential for teratoma formation. We found that canine iMSC downregulated expression of pluripotency genes and appeared morphologically similar to conventional MSC. Importantly, iMSC retained a stable phenotype after multiple passages, did not form teratomas in immune deficient mice, and did not induce tumor formation in dogs following systemic injection. We concluded therefore that iMSC were phenotypically stable, immunologically potent, safe with respect to tumor formation, and represented an important new source of cells for therapeutic modulation of inflammatory disorders. Copyright © 2017. Published by Elsevier B.V.

Osteoblastic mesenchymal stem cell sheet combined with Choukroun platelet-rich fibrin induces bone formation at an ectopic site.

PubMed

Wang, Zhifa; Weng, Yanming; Lu, Shengjun; Zong, Chunlin; Qiu, Jianyong; Liu, Yanpu; Liu, Bin

2015-08-01

To analyze the effects of platelet-rich fibrin (PRF) on mesenchymal stem cells (MSCs) in vitro and investigate in vivo bone formation by MSC sheets with PRF. Cell proliferation and expression of osteogenesis-related genes within MSC sheets were assessed upon exposure to PRF from the same donors. We then injected MSC sheet fragments with or without PRF subcutaneously in nude mice and assessed bone formation by micro-computed tomography and histological analyses. PRF significantly stimulated MSC proliferation and osteogenesis in vitro. MSC sheets injected with or without PRF formed new bone, but those with PRF produced significantly more and denser bone. MSC sheets can be used to generate tissue engineered bone upon injection, and PRF increases the osteogenic capacity of MSC sheets in vitro and in vivo. © 2014 Wiley Periodicals, Inc.

Lipopolysaccharide induces proliferation and osteogenic differentiation of adipose-derived mesenchymal stromal cells in vitro via TLR4 activation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Herzmann, Nicole; Salamon, Achim; Fiedler, Tomas

Multipotent mesenchymal stromal cells (MSC) are capable of multi-lineage differentiation and support regenerative processes. In bacterial infections, resident MSC can come intocontact with and need to react to bacterial components. Lipopolysaccharide (LPS), a typical structure of Gram-negative bacteria, increases the proliferation and osteogenic differentiation of MSC. LPS is usually recognized by the toll-like receptor (TLR) 4 and induces pro-inflammatory reactions in numerous cell types. In this study, we quantified the protein expression of TLR4 and CD14 on adipose-derived MSC (adMSC) in osteogenic differentiation and investigated the effect of TLR4 activation by LPS on NF-κB activation, proliferation and osteogenic differentiation ofmore » adMSC. We found that TLR4 is expressed on adMSC whereas CD14 is not, and that osteogenic differentiation induced an increase of the amount of TLR4 protein whereas LPS stimulation did not. Moreover, we could show that NF-κB activation via TLR4 occurs upon LPS treatment. Furthermore, we were able to show that competitive inhibition of TLR4 completely abolished the stimulatory effect of LPS on the proliferation and osteogenic differentiation of adMSC. In addition, the inhibition of TLR4 leads to the complete absence of osteogenic differentiation of adMSC, even when osteogenically stimulated. Thus, we conclude that LPS induces proliferation and osteogenic differentiation of adMSC in vitro through the activation of TLR4 and that the TLR4 receptor seems to play a role during osteogenic differentiation of adMSC.« less

Phenotypic and functional characterisation of ovine mesenchymal stem cells: application to a cartilage defect model.

PubMed

Mrugala, D; Bony, C; Neves, N; Caillot, L; Fabre, S; Moukoko, D; Jorgensen, C; Noël, D

2008-03-01

Multipotent mesenchymal stromal cells (MSC) are of particular interest for their potential clinical use in cartilage engineering, but a consistent model is missing in large animals. In the absence of any detailed study reporting a complete characterisation of the mesenchymal cells isolated from sheep bone marrow, we fully characterised adherent stromal cells and developed a pre-clinical model of cartilage engineering by implantation of autologous MSC in the Merinos sheep. Ovine MSC (oMSC) were isolated from bone marrow, expanded and further characterised according to the recently proposed definition of the MSC. The experimental model consists of partial-thickness lesions created in the inner part of the patellae of the posterior legs. Lesions were filled with oMSC with or without chitosan, with or without transforming growth factor (TGF)beta-3, in a fibrin clot. oMSC were shown to display the three main characteristics of MSC: adherence to plastic, phenotypic profile (positive for CD44, CD105, vimentin and negative for CD34 and CD45), and trilineage differentiation potential. We also report two other important functional characteristics of MSC: support of long-term haematopoiesis and immunosuppressive capacity. In vivo, 2 months after implantation the histological analysis revealed chondrocyte-like cells surrounded by a hyaline-like cartilaginous matrix that was integrated to the host cartilage when oMSC were combined with chitosan and TGFbeta-3. This study provides for the first time a strong characterisation of oMSC and establishes the basis for a model of cartilage engineering in a large animal.

78 FR 29387 - Government-Owned Inventions, Available for Licensing

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-20

....: MSC-24919-1: Systems and Methods for RFID-Enables Information Collection; NASA Case No.: MSC-25632-1... Methods for RFID-Enabled Dispenser; NASA Case No.: MSC-25313-1: Hydrostatic Hyperbaric Apparatus and...; NASA Case No: MSC-25590-1: Systems and Methods for RFID-Enabled Pressure Sensing Apparatus; NASA Case...

Numerical Simulation of Earth Pressure on Head Chamber of Shield Machine with FEM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li Shouju; Kang Chengang; Sun, Wei

2010-05-21

Model parameters of conditioned soils in head chamber of shield machine are determined based on tree-axial compression tests in laboratory. The loads acting on tunneling face are estimated according to static earth pressure principle. Based on Duncan-Chang nonlinear elastic constitutive model, the earth pressures on head chamber of shield machine are simulated in different aperture ratio cases for rotating cutterhead of shield machine. Relationship between pressure transportation factor and aperture ratio of shield machine is proposed by using aggression analysis.

Reliability Analysis of the MSC System

NASA Astrophysics Data System (ADS)

Kim, Young-Soo; Lee, Do-Kyoung; Lee, Chang-Ho; Woo, Sun-Hee

2003-09-01

MSC (Multi-Spectral Camera) is the payload of KOMPSAT-2, which is being developed for earth imaging in optical and near-infrared region. The design of the MSC is completed and its reliability has been assessed from part level to the MSC system level. The reliability was analyzed in worst case and the analysis results showed that the value complies the required value of 0.9. In this paper, a calculation method of reliability for the MSC system is described, and assessment result is presented and discussed.

Umbilical cord fibroblasts: Could they be considered as mesenchymal stem cells?

PubMed Central

Zeddou, Mustapha; Relic, Biserka; Malaise, Michel G

2014-01-01

In cell therapy protocols, many tissues were proposed as a source of mesenchymal stem cells (MSC) isolation. So far, bone marrow (BM) has been presented as the main source of MSC despite the invasive isolation procedure related to this source. During the last years, the umbilical cord (UC) matrix was cited in different studies as a reliable source from which long term ex vivo proliferating fibroblasts were isolated but with contradictory data about their immunophenotype, gene expression profile, and differentiation potential. Hence, an interesting question emerged: Are cells isolated from cord matrix (UC-MSC) different from other MSCs? In this review, we will summarize different studies that isolated and characterized UC-MSC. Considering BM-MSC as gold standard, we will discuss if UC-MSC fulfill different criteria that define MSC, and what remain to be done in this issue. PMID:25126385

Use of Small Fluorescent Molecules to Monitor Channel Activity

NASA Astrophysics Data System (ADS)

Jones, Sharon; Stringer, Sarah; Naik, Rajesh; Stone, Morley

2001-03-01

The Mechanosensitive channel of Large conductance (MscL) allows bacteria to rapidly adapt to changing environmental conditions such as osmolarity. The MscL channel opens in response to increases in membrane tension, which allows for the efflux of cytoplasmic constituents. Here we describe the cloning and expression of Salmonella typhimurium MscL (St-MscL). Using a fluorescence efflux assay, we demonstrate that efflux through the MscL channel during hypoosmotic shock can be monitored using endogenously produced fluorophores. In addition, we observe that thermal stimulation, i.e., heat shock, can also induce efflux through MscL. We present the first evidence of thermal activation of MscL efflux by heat shocking cells expressing the S. typhimurium protein variant. This finding has significant biosensor implications, especially for investigators exploring the use of channel proteins in biosensor applications. Thermal biosensors are relatively unexplored, but would have considerable commercial and military utility.

Tetrandrine identified in a small molecule screen to activate mesenchymal stem cells for enhanced immunomodulation.

PubMed

Yang, Zijiang; Concannon, John; Ng, Kelvin S; Seyb, Kathleen; Mortensen, Luke J; Ranganath, Sudhir; Gu, Fangqi; Levy, Oren; Tong, Zhixiang; Martyn, Keir; Zhao, Weian; Lin, Charles P; Glicksman, Marcie A; Karp, Jeffrey M

2016-07-26

Pre-treatment or priming of mesenchymal stem cells (MSC) prior to transplantation can significantly augment the immunosuppressive effect of MSC-based therapies. In this study, we screened a library of 1402 FDA-approved bioactive compounds to prime MSC. We identified tetrandrine as a potential hit that activates the secretion of prostaglandin E2 (PGE2), a potent immunosuppressive agent, by MSC. Tetrandrine increased MSC PGE2 secretion through the NF-κB/COX-2 signaling pathway. When co-cultured with mouse macrophages (RAW264.7), tetrandrine-primed MSC attenuated the level of TNF-α secreted by RAW264.7. Furthermore, systemic transplantation of primed MSC into a mouse ear skin inflammation model significantly reduced the level of TNF-α in the inflamed ear, compared to unprimed cells. Screening of small molecules to pre-condition cells prior to transplantation represents a promising strategy to boost the therapeutic potential of cell therapy.

Persistence of human parvovirus B19 in multipotent mesenchymal stromal cells expressing the erythrocyte P antigen: implications for transplantation

PubMed Central

Sundin, Mikael; Lindblom, Anna; Örvell, Claes; Barrett, A.John; Sundberg, Berit; Watz, Emma; Wikman, Agneta; Broliden, Kristina; Le Blanc, Katarina

2014-01-01

Multipotent mesenchymal stromal cells (MSC) are used to improve the outcome of hematopoietic stem cell transplantation and in regenerative medicine. However, MSC may harbor persistent viruses that may compromise their clinical benefit. Retrospectively screened, 1 of 20 MSC from healthy donors contained parvovirus B19 (B19) DNA. We found that MSC express the B19 receptor (the globoside P antigen) and a co-receptor (Ku 80), and can transmit B19 to bone marrow cells in vitro, suggesting that the virus can persist in the marrow stroma of healthy individuals. Two stem cell transplant patients received the B19 positive MSC as treatment for graft-versus-host disease. Neither developed viremia nor symptomatic B19 infection. These results demonstrate for the first time that persistent B19 in MSC can infect hematopoietic cells and underscore the importance of monitoring B19 transmission by MSC products. PMID:18804048

View of Mission Control Center celebrating conclusion of Apollo 11 mission

NASA Technical Reports Server (NTRS)

1969-01-01

Overall view of the Mission Operations Control Room in the Mission Control Center, bldg 30, Manned Spacecraft Center (MSC), at the conclusion of the Apollo 11 lunar landing mission. The television monitor shows President Richard M. Nixon greeting the Apollo 11 astronauts aboard the U.S.S. Hornet in the Pacific recovery area (40301); NASA and MSC Officials join the flight controllers in celebrating the conclusion of the Apollo 11 mission. From left foreground Dr. Maxime A. Faget, MSC Director of Engineering and Development; George S. Trimble, MSC Deputy Director; Dr. Christopher C. Kraft Jr., MSC Director fo Flight Operations; Julian Scheer (in back), Assistant Adminstrator, Offic of Public Affairs, NASA HQ.; George M. Low, Manager, Apollo Spacecraft Program, MSC; Dr. Robert R. Gilruth, MSC Director; and Charles W. Mathews, Deputy Associate Administrator, Office of Manned Space Flight, NASA HQ (40302).

Manufacture of Cryoshroud Surfaces for Space Simulation Chambers

NASA Technical Reports Server (NTRS)

Ash, Gary S.

2008-01-01

Environmental test chambers for space applications use internal shrouds to simulate temperature conditions encountered in space. Shroud temperatures may range from +150 C to -253 C (20 K), and internal surfaces are coated with special high emissivity/absorptivity paints. To obtain temperature uniformity over large areas, detailed thermal design is required for placement of tubing for gaseous or liquid nitrogen and helium and other exotic heat exchange fluids. The recent increase in space simulation activity related to the James Webb Space Telescope has led to the design of new cryogenic shrouds to meet critical needs in instrument package testing. This paper will review the design and manufacturing of shroud surfaces for several of these programs, including fabrication methods and the selection and application of paints for simulation chambers.

Predicted performance of an integrated modular engine system

NASA Technical Reports Server (NTRS)

Binder, Michael; Felder, James L.

1993-01-01

Space vehicle propulsion systems are traditionally comprised of a cluster of discrete engines, each with its own set of turbopumps, valves, and a thrust chamber. The Integrated Modular Engine (IME) concept proposes a vehicle propulsion system comprised of multiple turbopumps, valves, and thrust chambers which are all interconnected. The IME concept has potential advantages in fault-tolerance, weight, and operational efficiency compared with the traditional clustered engine configuration. The purpose of this study is to examine the steady-state performance of an IME system with various components removed to simulate fault conditions. An IME configuration for a hydrogen/oxygen expander cycle propulsion system with four sets of turbopumps and eight thrust chambers has been modeled using the Rocket Engine Transient Simulator (ROCETS) program. The nominal steady-state performance is simulated, as well as turbopump thrust chamber and duct failures. The impact of component failures on system performance is discussed in the context of the system's fault tolerant capabilities.

Human umbilical cord mesenchymal stem cells increase interleukin-9 production of CD4+ T cells

PubMed Central

Yang, Zhou Xin; Chi, Ying; Ji, Yue Ru; Wang, You Wei; Zhang, Jing; Luo, Wei Feng; Li, Li Na; Hu, Cai Dong; Zhuo, Guang Sheng; Wang, Li Fang; Han, Zhi-Bo; Han, Zhong Chao

2017-01-01

Mesenchymal stem cells (MSC) are able to differentiate into cells of multiple lineage, and additionally act to modulate the immune response. Interleukin (IL)-9 is primarily produced by cluster of differentiation (CD)4+ T cells to regulate the immune response. The present study aimed to investigate the effect of human umbilical cord derived-MSC (UC-MSC) on IL-9 production of human CD4+ T cells. It was demonstrated that the addition of UC-MSC to the culture of CD4+ T cells significantly enhanced IL-9 production by CD4+ T cells. Transwell experiments suggested that UC-MSC promotion of IL-9 production by CD4+ T cells was dependent on cell-cell contact. Upregulated expression of CD106 was observed in UC-MSC co-cultured with CD4+ T cells, and the addition of a blocking antibody of CD106 significantly impaired the ability of UC-MSC to promote IL-9 production by CD4+ T cells. Therefore, the results of the present study demonstrated that UC-MSC promoted the generation of IL-9 producing cells, which may be mediated, in part by CD106. The findings may act to expand understanding and knowledge of the immune modulatory role of UC-MSC. PMID:29042945

Transplantation of mesenchymal stem cells overexpressing IL10 attenuates cardiac impairments in rats with myocardial infarction.

PubMed

Meng, Xin; Li, Jianping; Yu, Ming; Yang, Jian; Zheng, Minjuan; Zhang, Jinzhou; Sun, Chao; Liang, Hongliang; Liu, Liwen

2018-01-01

Mesenchymal stem cell (MSC) has been well known to exert therapeutic potential for patients with myocardial infarction (MI). In addition, interleukin-10 (IL10) could attenuate MI through suppressing inflammation. Thus, the combination of MSC implantation with IL10 delivery may extend health benefits to ameliorate cardiac injury after MI. Here we established overexpression of IL10 in bone marrow-derived MSC through adenoviral transduction. Cell viability, apoptosis, and IL10 secretion under ischemic challenge in vitro were examined. In addition, MSC was transplanted into the injured hearts in a rat model of MI. Four weeks after the MI induction, MI, cardiac functions, apoptotic cells, and inflammation cytokines were assessed. In response to in vitro oxygen-glucose deprivation (OGD), IL10 overexpression in MSC (Ad.IL10-MSC) enhanced cell viability, decreased apoptosis, and increased IL10 secretion. Consistently, the implantation of Ad.IL10-MSCs into MI animals resulted in more reductions in myocardial infarct size, cardiac impairment, and cell apoptosis, compared to the individual treatments of either MSC or IL10 administration. Moreover, the attenuation of both systemic and local inflammations was most prominent for Ad.IL10-MSC treatment. IL10 overexpression and MSC may exert a synergistic anti-inflammatory effect to alleviate cardiac injury after MI. © 2017 Wiley Periodicals, Inc.

Synergistic Effects of GDNF and VEGF on Lifespan and Disease Progression in a Familial ALS Rat Model

PubMed Central

Krakora, Dan; Mulcrone, Patrick; Meyer, Michael; Lewis, Christina; Bernau, Ksenija; Gowing, Genevieve; Zimprich, Chad; Aebischer, Patrick; Svendsen, Clive N; Suzuki, Masatoshi

2013-01-01

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by the progressive loss of motor neurons in the brain and spinal cord. We have recently shown that human mesenchymal stem cells (hMSCs) modified to release glial cell line-derived neurotrophic factor (GDNF) decrease disease progression in a rat model of ALS when delivered to skeletal muscle. In the current study, we determined whether or not this effect could be enhanced by delivering GDNF in concert with other trophic factors. hMSC engineered to secrete GDNF (hMSC-GDNF), vascular endothelial growth factor (hMSC-VEGF), insulin-like growth factor-I (hMSC-IGF-I), or brain-derived neurotrophic factor (hMSC-BDNF), were prepared and transplanted bilaterally into three muscle groups. hMSC-GDNF and hMSC-VEGF prolonged survival and slowed the loss of motor function, but hMSC-IGF-I and hMSC-BDNF did not have any effect. We then tested the efficacy of a combined ex vivo delivery of GDNF and VEGF in extending survival and protecting neuromuscular junctions (NMJs) and motor neurons. Interestingly, the combined delivery of these neurotrophic factors showed a strong synergistic effect. These studies further support ex vivo gene therapy approaches for ALS that target skeletal muscle. PMID:23712039

Long-term efficiency of mesenchymal stromal cell-mediated CD-MSC/5FC therapy in human melanoma xenograft model.

PubMed

Kucerova, L; Skolekova, S; Demkova, L; Bohovic, R; Matuskova, M

2014-10-01

Mesenchymal stromal cells (MSC) can be exploited as cellular delivery vehicles for the enzymes converting non-toxic prodrugs to toxic substances. Because of their inherent chemoresistance, they exert potent bystander and antitumor effect. Here we show that the human adipose tissue-derived MSC expressing fusion yeast cytosine deaminase::uracil phosphoribosyltransferase (CD-MSC) in combination with 5-fluorocytosine (5FC) mediated a long-term tumor-free survival in the 83.3% of tumor-bearing animals. CD-MSC/5FC treatment induced cytotoxicity against model human melanoma cells EGFP-A375. Only 4% of the therapeutic CD-MSC cells eliminated >98.5% of the tumor cells in vitro. Long-term tumor-free survival was confirmed in 15 out of the 18 animals. However, repeatedly used CD-MSC/5FC therapeutic regimen generated more aggressive and metastatic variant of the melanoma cells EGFP-A375/Rel3. These cells derived from the refractory xenotransplants exhibited increased resistance to the CD-MSC/5FC treatment, altered cell adhesion, migration, tumorigenic and metastatic properties. However, long-term curative effect was achieved by the augmentation of the CD-MSC/5FC regimen along with the inhibition of c-Met/hepatocyte growth factor signaling axis in this aggressive melanoma derivative. In summary, the CD-MSC/5FC regimen can be regarded as a very effective antitumor approach to achieve long-term tumor-free survival as demonstrated on a mouse model of aggressive human melanoma xenografts.

Nanog reverses the effects of organismal aging on mesenchymal stem cell proliferation and myogenic differentiation potential

PubMed Central

Han, Juhee; Mistriotis, Panagiotis; Lei, Pedro; Wang, Dan; Liu, Song; Andreadis, Stelios T.

2012-01-01

Although the therapeutic potential of mesenchymal stem cells (MSC) is widely accepted, loss of cell function due to donor aging or culture senescence are major limiting factors hampering their clinical application. Our laboratory recently showed that MSC originating from older donors suffer from limited proliferative capacity and significantly reduced myogenic differentiation potential. This is a major concern, as the patients most likely to suffer from cardiovascular disease are elderly. Here we tested the hypothesis that a single pluripotency associated transcription factor, namely Nanog, may reverse the proliferation and differentiation potential of BM-MSC from adult donors. Microarray analysis showed that adult (a)BM-MSC expressing Nanog clustered close to Nanog-expressing neonatal cells. Nanog markedly upregulated genes involved in cell cycle, DNA replication and DNA damage repair and enhanced the proliferation rate and clonogenic capacity of aBM-MSC. Notably, Nanog reversed the myogenic differentiation potential and restored the contractile function of aBM-MSC to a similar level as that of neonatal (n)BM-MSC. The effect of Nanog on contractility was mediated – at least in part - through activation of the TGF-β pathway by diffusible factors secreted in the conditioned medium of Nanog-expressing BM-MSC. Overall, our results suggest that Nanog may be used to overcome the effects of organismal aging on aBM-MSC, thereby increasing the potential of MSC from aged donors for cellular therapy and tissue regeneration. PMID:22949105

Exosomes Derived from Mesenchymal Stromal Cells Promote Axonal Growth of Cortical Neurons.

PubMed

Zhang, Yi; Chopp, Michael; Liu, Xian Shuang; Katakowski, Mark; Wang, Xinli; Tian, Xinchu; Wu, David; Zhang, Zheng Gang

2017-05-01

Treatment of brain injury with exosomes derived from mesenchymal stromal cells (MSCs) enhances neurite growth. However, the direct effect of exosomes on axonal growth and molecular mechanisms underlying exosome-enhanced neurite growth are not known. Using primary cortical neurons cultured in a microfluidic device, we found that MSC-exosomes promoted axonal growth, whereas attenuation of argonaut 2 protein, one of the primary microRNA (miRNA) machinery proteins, in MSC-exosomes abolished their effect on axonal growth. Both neuronal cell bodies and axons internalized MSC-exosomes, which was blocked by botulinum neurotoxins (BoNTs) that cleave proteins of the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex. Moreover, tailored MSC-exosomes carrying elevated miR-17-92 cluster further enhanced axonal growth compared to native MSC-exosomes. Quantitative RT-PCR and Western blot analysis showed that the tailored MSC-exosomes increased levels of individual members of this cluster and activated the PTEN/mTOR signaling pathway in recipient neurons, respectively. Together, our data demonstrate that native MSC-exosomes promote axonal growth while the tailored MSC-exosomes can further boost this effect and that tailored exosomes can deliver their selective cargo miRNAs into and activate their target signals in recipient neurons. Neuronal internalization of MSC-exosomes is mediated by the SNARE complex. This study reveals molecular mechanisms that contribute to MSC-exosome-promoted axonal growth, which provides a potential therapeutic strategy to enhance axonal growth.

Immunomodulatory Properties of Induced Pluripotent Stem Cell-Derived Mesenchymal Cells.

PubMed

Ng, Jia; Hynes, Kim; White, Gregory; Sivanathan, Kisha Nandini; Vandyke, Kate; Bartold, Peter Mark; Gronthos, Stan

2016-12-01

MSC-like populations derived from induced pluripotent stem cells (iPSC-MSC) serve as an alternative stem cell source due to their high proliferative capacity. In this study, we assessed the immunomodulatory potential of iPSC-MSC generated from periodontal ligament (PDL) and gingival (GF) tissue. The iPSC-MSC lines exhibited a similar level of suppression of mitogen-stimulated peripheral blood mononuclear cells (PBMNC) proliferation compared to their respective parental fibroblast populations in vitro. Moreover, iPSC-MSC demonstrated the ability to suppress T-cells effector cells, Th1/Th2/Th17 populations, and increase levels of Treg cells. In order to investigate the mechanisms involved, expression of common MSC-derived soluble factors known to supress lymphocyte proliferation were assessed in iPSC-MSC cultured with PBMNC with direct cell-cell contact or separated in transwells. Real-time PCR analysis of factors known to be involved in MSC mediated immune regulation, found a general trend of elevated IDO1 and IL6 transcript levels in iPSC-MSC lines and their respective primary cells co-cultured with activated PBMNC, with a wide range of gene expression levels between the different mesenchymal cell types. The results suggest that different iPSC-MSC may be useful as a potential alternative source of cells for future clinical use in therapeutic applications because of their potent immunosuppressive properties. J. Cell. Biochem. 117: 2844-2853, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Estrogenic effects of marijuana smoke condensate and cannabinoid compounds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Soo Yeun; Sungkyunkwan University, 300 Cheoncheon-dong, Jangan-gu, Suwon, Gyeonggi-do 440-746; Oh, Seung Min

Chronic exposure to marijuana produces adverse effects on the endocrine and reproductive systems in humans; however, the experimental evidence for this presented thus far has not been without controversy. In this study, the estrogenic effect of marijuana smoke condensate (MSC) was evaluated using in vitro bioassays, viz., the cell proliferation assay, the reporter gene assay, and the ER competitive binding assay. The results of these assays were compared with those of three major cannabinoids, i.e., THC, CBD, and CBN. The estrogenic effect of MSC was further confirmed by the immature female rat uterotrophic assay. MSC stimulated the estrogenicity related tomore » the ER-mediated pathway, while neither THC, CBD, nor CBN did. Moreover, treatment with 10 and 25 mg/kg MSC induced significant uterine response, and 10 mg/kg MSC resulted in an obvious change in the uterine epithelial cell appearance. MSC also enhanced the IGFBP-1 gene expression in a dose-dependent manner. To identify the constituents of MSC responsible for its estrogenicity, the MSC fractionated samples were examined using another cell proliferation assay, and the estrogenic active fraction was analyzed using GC-MS. In the organic acid fraction that showed the strongest estrogenic activity among the seven fractions of MSC, phenols were identified. Our results suggest that marijuana abuse is considered an endocrine-disrupting factor. Furthermore, these results suggest that the phenolic compounds contained in MSC play a role in its estrogenic effect.« less

Attenuation of aortic aneurysms with stem cells from different genders.

PubMed

Davis, John P; Salmon, Morgan; Pope, Nicolas H; Lu, Guanyi; Su, Gang; Sharma, Ashish K; Ailawadi, Gorav; Upchurch, Gilbert R

2015-11-01

No medical therapies are yet available to slow abdominal aortic aneurysm (AAA) growth. This study sought to investigate the effect of different genders of bone marrow-derived mesenchymal stem cells (MSC) on AAA growth in a murine AAA model. Given the decreased rate of AAA in women, it is hypothesized that female MSC would attenuate AAA growth more so than male MSC. Aortas of 8-10-wk-old male C57Bl/6 mice were perfused with purified porcine pancreatic elastase to induce AAA formation. Bone marrow-derived MSC from male and female mice were dosed via tail vein injection (3 million cells per dose, 500 μL of volume per injection) on postaortic perfusion days 1, 3, and 5. Aortas were harvested after 14 d. Mean aortic dilation in the elastase group was 121 ± 5.2% (mean ± standard error of the mean), while male MSC inhibited AAA growth (87.8 ± 6.9%, P = 0.008) compared with that of elastase. Female MSC showed the most marked attenuation of AAA growth (75.2 ± 8.3% P = 0.0004). Proinflammatory cytokines tumor necrosis factor α, interleukin 1β, and monocyte chemotactic protein-1 (MCP-1) were only decreased in tissues treated with female MSC (P = 0.017, P = 0.001, and P < 0.0001, respectively, when compared with elastase). These data exhibit that female MSC more strongly attenuate AAA growth in the murine model. Furthermore, female MSC and male MSC inhibit proinflammatory cytokines at varying levels. The effects of MSC on aortic tissue offer a promising insight into biologic therapies for future medical treatment of AAAs in humans. Copyright © 2015 Elsevier Inc. All rights reserved.

Multimodality Molecular Imaging of Cardiac Cell Transplantation: Part I. Reporter Gene Design, Characterization, and Optical in Vivo Imaging of Bone Marrow Stromal Cells after Myocardial Infarction

PubMed Central

Parashurama, Natesh; Ahn, Byeong-Cheol; Ziv, Keren; Ito, Ken; Paulmurugan, Ramasamy; Willmann, Jürgen K.; Chung, Jaehoon; Ikeno, Fumiaki; Swanson, Julia C.; Merk, Denis R.; Lyons, Jennifer K.; Yerushalmi, David; Teramoto, Tomohiko; Kosuge, Hisanori; Dao, Catherine N.; Ray, Pritha; Patel, Manishkumar; Chang, Ya-fang; Mahmoudi, Morteza; Cohen, Jeff Eric; Goldstone, Andrew Brooks; Habte, Frezghi; Bhaumik, Srabani; Yaghoubi, Shahriar; Robbins, Robert C.; Dash, Rajesh; Yang, Phillip C.; Brinton, Todd J.; Yock, Paul G.; McConnell, Michael V.

2016-01-01

Purpose To use multimodality reporter-gene imaging to assess the serial survival of marrow stromal cells (MSC) after therapy for myocardial infarction (MI) and to determine if the requisite preclinical imaging end point was met prior to a follow-up large-animal MSC imaging study. Materials and Methods Animal studies were approved by the Institutional Administrative Panel on Laboratory Animal Care. Mice (n = 19) that had experienced MI were injected with bone marrow–derived MSC that expressed a multimodality triple fusion (TF) reporter gene. The TF reporter gene (fluc2-egfp-sr39ttk) consisted of a human promoter, ubiquitin, driving firefly luciferase 2 (fluc2), enhanced green fluorescent protein (egfp), and the sr39tk positron emission tomography reporter gene. Serial bioluminescence imaging of MSC-TF and ex vivo luciferase assays were performed. Correlations were analyzed with the Pearson product-moment correlation, and serial imaging results were analyzed with a mixed-effects regression model. Results Analysis of the MSC-TF after cardiac cell therapy showed significantly lower signal on days 8 and 14 than on day 2 (P = .011 and P = .001, respectively). MSC-TF with MI demonstrated significantly higher signal than MSC-TF without MI at days 4, 8, and 14 (P = .016). Ex vivo luciferase activity assay confirmed the presence of MSC-TF on days 8 and 14 after MI. Conclusion Multimodality reporter-gene imaging was successfully used to assess serial MSC survival after therapy for MI, and it was determined that the requisite preclinical imaging end point, 14 days of MSC survival, was met prior to a follow-up large-animal MSC study. © RSNA, 2016 Online supplemental material is available for this article. PMID:27308957

Advanced Small Rocket Chambers. Basic Program and Option 2: Fundamental Processes and Material Evaluation

NASA Technical Reports Server (NTRS)

Jassowski, Donald M.

1993-01-01

Propellants, chamber materials, and processes for fabrication of small high performance radiation cooled liquid rocket engines were evaluated to determine candidates for eventual demonstration in flight-type thrusters. Both storable and cryogenic propellant systems were considered. The storable propellant systems chosen for further study were nitrogen tetroxide oxidizer with either hydrazine or monomethylhydrazine as fuel. The cryogenic propellants chosen were oxygen with either hydrogen or methane as fuel. Chamber material candidates were chemical vapor deposition (CVD) rhenium protected from oxidation by CVD iridium for the chamber hot section, and film cooled wrought platinum-rhodium or regeneratively cooled stainless steel for the front end section exposed to partially reacted propellants. Laser diagnostics of the combustion products near the hot chamber surface and measurements at the surface layer were performed in a collaborative program at Sandia National Laboratories, Livermore, CA. The Material Sample Test Apparatus, a laboratory system to simulate the combustion environment in terms of gas and material temperature, composition, and pressure up to 6 Atm, was developed for these studies. Rocket engine simulator studies were conducted to evaluate the materials under simulated combustor flow conditions, in the diagnostic test chamber. These tests used the exhaust species measurement system, a device developed to monitor optically species composition and concentration in the chamber and exhaust by emission and absorption measurements.

Bone marrow-derived mesenchymal stem/stromal cells reverse the sensorial diabetic neuropathy via modulation of spinal neuroinflammatory cascades.

PubMed

Evangelista, Afrânio Ferreira; Vannier-Santos, Marcos André; de Assis Silva, Gessica Sabrina; Silva, Daniela Nascimento; Juiz, Paulo José Lima; Nonaka, Carolina Kymie Vasques; Dos Santos, Ricardo Ribeiro; Soares, Milena Botelho Pereira; Villarreal, Cristiane Flora

2018-06-22

Diabetic neuropathy (DN) is a frequent and debilitating manifestation of diabetes mellitus, to which there are no effective therapeutic approaches. Mesenchymal stem/stromal cells (MSC) have a great potential for the treatment of this syndrome, possibly through regenerative actions on peripheral nerves. Here, we evaluated the therapeutic effects of MSC on spinal neuroinflammation, as well as on ultrastructural aspects of the peripheral nerve in DN-associated sensorial dysfunction. C57Bl/6 mice were treated with bone marrow-derived MSC (1 × 10 6 ), conditioned medium from MSC cultures (CM-MSC) or vehicle by endovenous route following the onset of streptozotocin (STZ)-induced diabetes. Paw mechanical and thermal nociceptive thresholds were evaluated by using von Frey filaments and Hargreaves test, respectively. Morphological and morphometric analysis of the sciatic nerve was performed by light microscopy and transmission electron microscopy. Mediators and markers of neuroinflammation in the spinal cord were measured by radioimmunoassay, real-time PCR, and immunofluorescence analyses. Diabetic mice presented behavioral signs of sensory neuropathy, mechanical allodynia, and heat hypoalgesia, which were completely reversed by a single administration of MSC or CM-MSC. The ultrastructural analysis of the sciatic nerve showed that diabetic mice exhibited morphological and morphometric alterations, considered hallmarks of DN, such as degenerative changes in axons and myelin sheath, and reduced area and density of unmyelinated fibers. In MSC-treated mice, these structural alterations were markedly less commonly observed and/or less pronounced. Moreover, MSC transplantation inhibited multiple parameters of spinal neuroinflammation found in diabetic mice, causing the reduction of activated astrocytes and microglia, oxidative stress signals, galectin-3, IL-1β, and TNF-α production. Conversely, MSC increased the levels of anti-inflammatory cytokines, IL-10, and TGF-β. The present study described the modulatory effects of MSC on spinal cord neuroinflammation in diabetic mice, suggesting new mechanisms by which MSC can improve DN.

Comparison of exosomes secreted by induced pluripotent stem cell-derived mesenchymal stem cells and synovial membrane-derived mesenchymal stem cells for the treatment of osteoarthritis.

PubMed

Zhu, Yu; Wang, Yuchen; Zhao, Bizeng; Niu, Xin; Hu, Bin; Li, Qing; Zhang, Juntao; Ding, Jian; Chen, Yunfeng; Wang, Yang

2017-03-09

Osteoarthritis (OA) is the most common joint disease worldwide. In the past decade, mesenchymal stem cells (MSCs) have been used widely for the treatment of OA. A potential mechanism of MSC-based therapies has been attributed to the paracrine secretion of trophic factors, in which exosomes may play a major role. In this study, we aimed to compare the effectiveness of exosomes secreted by synovial membrane MSCs (SMMSC-Exos) and exosomes secreted by induced pluripotent stem cell-derived MSCs (iMSC-Exos) on the treatment of OA. Induced pluripotent stem cell-derived MSCs and synovial membrane MSCs were characterized by flow cytometry. iMSC-Exos and SMMSC-Exos were isolated using an ultrafiltration method. Tunable resistive pulse-sensing analysis, transmission electron microscopy, and western blots were used to identify exosomes. iMSC-Exos and SMMSC-Exos were injected intra-articularly in a mouse model of collagenase-induced OA and the efficacy of exosome injections was assessed by macroscopic, histological, and immunohistochemistry analysis. We also evaluated the effects of iMSC-Exos and SMMSC-Exos on proliferation and migration of human chondrocytes by cell-counting and scratch assays, respectively. The majority of iMSC-Exos and SMMSC-Exos were approximately 50-150 nm in diameter and expressed CD9, CD63, and TSG101. The injection of iMSC-Exos and SMMSC-Exos both attenuated OA in the mouse OA model, but iMSC-Exos had a superior therapeutic effect compared with SMMSC-Exos. Similarly, chondrocyte migration and proliferation were stimulated by both iMSC-Exos and SMMSC-Exos, with iMSC-Exos exerting a stronger effect. The present study demonstrated that iMSC-Exos have a greater therapeutic effect on OA than SMMSC-Exos. Because autologous iMSCs are theoretically inexhaustible, iMSC-Exos may represent a novel therapeutic approach for the treatment of OA.

Genetically engineered mesenchymal stromal cells producing TNFα have tumour suppressing effect on human melanoma xenograft.

PubMed

Tyciakova, Silvia; Matuskova, Miroslava; Bohovic, Roman; Polakova, Katarina; Toro, Lenka; Skolekova, Svetlana; Kucerova, Lucia

2015-01-01

Mesenchymal stromal cells (MSC) are a promising tool for targeted cancer therapy due to their tumour-homing ability. Intrinsic resistance enables the MSC to longer tolerate therapeutic factors, such as prodrug converting enzymes, cytokines and pro-apoptotic proteins. Tumour necrosis factor alpha (TNFα) is known to be cytotoxic to a variety of cancer cells and exert a tumour-destructive capacity. MSC were retrovirally transduced to stable express an exogenous gene encoding the desired therapeutic agent hTNFα. The effect of a TNFα-producing adipose tissue-derived MSC (AT-MSC/hTNFα) was tested on the tumour cell lines of different origins: melanoma (A375), breast carcinoma (SKBR3, MDA-MB-231), colon carcinoma (HT29), ovarian carcinoma (SKOV3) and glioblastoma (U87-MG) cells. The tumour suppressing effect of AT-MSC/hTNFα on A375 melanoma xenografts was monitored in an immunodeficient mouse model in vivo. Engineered AT-MSC are able to constitutively secrete human TNFα protein, induce apoptosis of tumour cell lines via caspase 3/7 activation and inhibit the tumour cell proliferation in vitro. Melanoma A375 and breast carcinoma SKBR3 cells were the most sensitive, and their proliferation in vitro was reduced by conditioned media produced by AT-MSC/hTNFα to 60% and 40%, respectively. The previously reported tumour supportive effect of AT-MSC on subcutaneous A375 melanoma xenograft growth was neutralised and suppressed by engineered AT-MSC stably producing hTNFα. When AT-MSC/hTNFα were coinjected with A375 melanoma cells, the tumour mass inhibition was up to 97.5%. The results of the present study demonstrate that tumour cells respond to hTNFα-based treatment mediated by genetically engineered AT-MSC/hTNFα both in vitro and in vivo. Copyright © 2015 John Wiley & Sons, Ltd.

Modeling and simulation of flow field in giant magnetostrictive pump

NASA Astrophysics Data System (ADS)

Zhao, Yapeng; Ren, Shiyong; Lu, Quanguo

2017-09-01

Recent years, there has been significant research in the design and analysis of giant magnetostrictive pump. In this paper, the flow field model of giant magnetostrictive pump was established and the relationship between pressure loss and working frequency of piston was studied by numerical simulation method. Then, the influence of different pump chamber height on pressure loss in giant magnetostrictive pump was studied by means of flow field simulation. Finally, the fluid pressure and velocity vector distribution in giant magnetostrictive pump chamber were simulated.

Tension-activated channels in the mechanism of osmotic fitness in Pseudomonas aeruginosa

PubMed Central

Rowe, Ian; Schams, Anthony; Mayhew, Christina

2017-01-01

Pseudomonas aeruginosa (PA) is an opportunistic pathogen with an exceptional ability to adapt to a range of environments. Part of its adaptive potential is the ability to survive drastic osmolarity changes. Upon a sudden dilution of external medium, such as during exposure to rain, bacteria evade mechanical rupture by engaging tension-activated channels that act as osmolyte release valves. In this study, we compare fast osmotic permeability responses in suspensions of wild-type PA and Escherichia coli (EC) strains in stopped-flow experiments and provide electrophysiological descriptions of osmotic-release channels in PA. Using osmotic dilution experiments, we first show that PA tolerates a broader range of shocks than EC. We record the kinetics of cell equilibration reported by light scattering responses to osmotic up- and down-shocks. PA exhibits a lower water permeability and faster osmolyte release rates during large osmotic dilutions than EC, which correlates with better survival. To directly characterize the PA tension-activated channels, we generate giant spheroplasts from this microorganism and record current responses in excised patches. Unlike EC, which relies primarily on two types of channels, EcMscS and EcMscL, to generate a distinctive two-wave pressure ramp response, PA exhibits a more gradual response that is dominated by MscL-type channels. Genome analysis, cloning, and expression reveal that PA possesses one MscL-type (PaMscL) and two MscS-type (PaMscS-1 and 2) proteins. In EC spheroplasts, both PaMscS channels exhibit a slightly earlier activation by pressure compared with EcMscS. Unitary currents reveal that PaMscS-2 has a smaller conductance, higher anionic preference, stronger inactivation, and slower recovery compared with PaMscS-1. We conclude that PA relies on MscL as the major valve defining a high rate of osmolyte release sufficient to curb osmotic swelling under extreme shocks, but it still requires MscS-type channels with a strong propensity to inactivation to properly terminate massive permeability response. PMID:28424229

A Novel Corynebacterium glutamicum l-Glutamate Exporter.

PubMed

Wang, Yu; Cao, Guoqiang; Xu, Deyu; Fan, Liwen; Wu, Xinyang; Ni, Xiaomeng; Zhao, Shuxin; Zheng, Ping; Sun, Jibin; Ma, Yanhe

2018-03-15

Besides metabolic pathways and regulatory networks, transport systems are also pivotal for cellular metabolism and hyperproduction of biochemicals using microbial cell factories. The identification and characterization of transporters are therefore of great significance for the understanding and engineering of transport reactions. Herein, a novel l-glutamate exporter, MscCG2, which exists extensively in Corynebacterium glutamicum strains but is distinct from the only known l-glutamate exporter, MscCG, was discovered in an industrial l-glutamate-producing C. glutamicum strain. MscCG2 was predicted to possess three transmembrane helices in the N-terminal region and located in the cytoplasmic membrane, which are typical structural characteristics of the mechanosensitive channel of small conductance. MscCG2 has a low amino acid sequence identity (23%) to MscCG and evolved separately from MscCG with four transmembrane helices. Despite the considerable differences between MscCG2 and MscCG in sequence and structure, gene deletion and complementation confirmed that MscCG2 also functioned as an l-glutamate exporter and an osmotic safety valve in C. glutamicum Besides, transcriptional analysis showed that MscCG2 and MscCG genes were transcribed in similar patterns and not induced by l-glutamate-producing conditions. It was also demonstrated that MscCG2-mediated l-glutamate excretion was activated by biotin limitation or penicillin treatment and that constitutive l-glutamate excretion was triggered by a gain-of-function mutation of MscCG2 (A151V). Discovery of MscCG2 will enrich the understanding of bacterial amino acid transport and provide additional targets for exporter engineering. IMPORTANCE The exchange of matter, energy, and information with surroundings is fundamental for cellular metabolism. Therefore, studying transport systems that are essential for these processes is of great significance. Besides, transport systems of bacterial cells are usually related to product excretion as well as product reuptake, making transporter engineering a useful strategy for strain improvement. The significance of our research is in identifying and characterizing a novel l-glutamate exporter from the industrial workhorse Corynebacterium glutamicum , which will enrich the understanding of l-glutamate excretion and provide a new target for studying bacterial amino acid transport and engineering transport reactions. Copyright © 2018 American Society for Microbiology.

Large-scale expansion of Wharton's jelly-derived mesenchymal stem cells on gelatin microbeads, with retention of self-renewal and multipotency characteristics and the capacity for enhancing skin wound healing.

PubMed

Zhao, Guifang; Liu, Feilin; Lan, Shaowei; Li, Pengdong; Wang, Li; Kou, Junna; Qi, Xiaojuan; Fan, Ruirui; Hao, Deshun; Wu, Chunling; Bai, Tingting; Li, Yulin; Liu, Jin Yu

2015-03-19

Successful stem cell therapy relies on large-scale generation of stem cells and their maintenance in a proliferative multipotent state. This study aimed to establish a three-dimension culture system for large-scale generation of hWJ-MSC and investigated the self-renewal activity, genomic stability and multi-lineage differentiation potential of such hWJ-MSC in enhancing skin wound healing. hWJ-MSC were seeded on gelatin microbeads and cultured in spinning bottles (3D). Cell proliferation, karyotype analysis, surface marker expression, multipotent differentiation (adipogenic, chondrogenic, and osteogenic potentials), and expression of core transcription factors (OCT4, SOX2, NANOG, and C-MYC), as well as their efficacy in accelerating skin wound healing, were investigated and compared with those of hWJ-MSC derived from plate cultres (2D), using in vivo and in vitro experiments. hWJ-MSC attached to and proliferated on gelatin microbeads in 3D cultures reaching a maximum of 1.1-1.30×10(7) cells on 0.5 g of microbeads by days 8-14; in contrast, hWJ-MSC derived from 2D cultures reached a maximum of 6.5 -11.5×10(5) cells per well in a 24-well plate by days 6-10. hWJ-MSC derived by 3D culture incorporated significantly more EdU (P<0.05) and had a significantly higher proliferation index (P<0.05) than those derived from 2D culture. Immunofluorescence staining, real-time PCR, flow cytometry analysis, and multipotency assays showed that hWJ-MSC derived from 3D culture retained MSC surface markers and multipotency potential similar to 2D culture-derived cells. 3D culture-derived hWJ-MSC also retained the expression of core transcription factors at levels comparable to their 2D culture counterparts. Direct injection of hWJ-MSC derived from 3D or 2D cultures into animals exhibited similar efficacy in enhancing skin wound healing. Thus, hWJ-MSC can be expanded markedly in gelatin microbeads, while retaining MSC surface marker expression, multipotent differential potential, and expression of core transcription factors. These cells also efficiently enhanced skin wound healing in vivo, in a manner comparable to that of hWJ-MSC obtained from 2D culture.

Performance of the Satellite Test Assistant Robot in JPL's Space Simulation Facility

NASA Technical Reports Server (NTRS)

Mcaffee, Douglas; Long, Mark; Johnson, Ken; Siebes, Georg

1995-01-01

An innovative new telerobotic inspection system called STAR (the Satellite Test Assistant Robot) has been developed to assist engineers as they test new spacecraft designs in simulated space environments. STAR operates inside the ultra-cold, high-vacuum, test chambers and provides engineers seated at a remote Operator Control Station (OCS) with high resolution video and infrared (IR) images of the flight articles under test. STAR was successfully proof tested in JPL's 25-ft (7.6-m) Space Simulation Chamber where temperatures ranged from +85 C to -190 C and vacuum levels reached 5.1 x 10(exp -6) torr. STAR's IR Camera was used to thermally map the entire interior of the chamber for the first time. STAR also made several unexpected and important discoveries about the thermal processes occurring within the chamber. Using a calibrated test fixture arrayed with ten sample spacecraft materials, the IR camera was shown to produce highly accurate surface temperature data. This paper outlines STAR's design and reports on significant results from the thermal vacuum chamber test.

The numerical modelling and process simulation for the fault diagnosis of rotary kiln incinerator.

PubMed

Roh, S D; Kim, S W; Cho, W S

2001-10-01

The numerical modelling and process simulation for the fault diagnosis of rotary kiln incinerator were accomplished. In the numerical modelling, two models applied to the modelling within the kiln are the combustion chamber model including the mass and energy balance equations for two combustion chambers and 3D thermal model. The combustion chamber model predicts temperature within the kiln, flue gas composition, flux and heat of combustion. Using the combustion chamber model and 3D thermal model, the production-rules for the process simulation can be obtained through interrelation analysis between control and operation variables. The process simulation of the kiln is operated with the production-rules for automatic operation. The process simulation aims to provide fundamental solutions to the problems in incineration process by introducing an online expert control system to provide an integrity in process control and management. Knowledge-based expert control systems use symbolic logic and heuristic rules to find solutions for various types of problems. It was implemented to be a hybrid intelligent expert control system by mutually connecting with the process control systems which has the capability of process diagnosis, analysis and control.

Coarse-grained discrete particle simulations of particle segregation in rotating fluidized beds in vortex chambers [Discrete particle simulations of particle segregation in rotating fluidized beds in vortex chambers

DOE PAGES

Verma, Vikrant; Li, Tingwen; De Wilde, Juray

2017-05-26

Vortex chambers allow the generation of rotating fluidized beds, offering high-G intensified gas-solid contact, gas-solids separation and solids-solids segregation. Focusing on binary particle mixtures and fixing the density and diameter of the heavy/large particles, transient batch CFD-coarse-grained DPM simulations were carried out with varying densities or sizes of the light/small particles to evaluate to what extent combining these three functionalities is possible within a vortex chamber of given design. Both the rate and quality of segregation were analyzed. Within a relatively wide density and size range, fast and efficient segregation takes place, with an inner and slower rotating bed ofmore » the lighter/small particles forming within the outer and faster rotating bed of the heavier/large particles. Simulations show that the contamination of the outer bed with lighter particles occurs more easily than contamination of the inner bed with heavier particles and increases with decreasing difference in size or density of the particles. Bubbling in the inner bed is observed with an inner bed of very low density or small particles. Porosity plots show that vortex chambers with a sufficient number of gas inlet slots have to be used to guarantee a uniform gas distribution and particle bed. Lastly, the flexibility of particle segregation in vortex chambers with respect to the gas flow rate is demonstrated.« less

Coarse-grained discrete particle simulations of particle segregation in rotating fluidized beds in vortex chambers [Discrete particle simulations of particle segregation in rotating fluidized beds in vortex chambers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Verma, Vikrant; Li, Tingwen; De Wilde, Juray

Vortex chambers allow the generation of rotating fluidized beds, offering high-G intensified gas-solid contact, gas-solids separation and solids-solids segregation. Focusing on binary particle mixtures and fixing the density and diameter of the heavy/large particles, transient batch CFD-coarse-grained DPM simulations were carried out with varying densities or sizes of the light/small particles to evaluate to what extent combining these three functionalities is possible within a vortex chamber of given design. Both the rate and quality of segregation were analyzed. Within a relatively wide density and size range, fast and efficient segregation takes place, with an inner and slower rotating bed ofmore » the lighter/small particles forming within the outer and faster rotating bed of the heavier/large particles. Simulations show that the contamination of the outer bed with lighter particles occurs more easily than contamination of the inner bed with heavier particles and increases with decreasing difference in size or density of the particles. Bubbling in the inner bed is observed with an inner bed of very low density or small particles. Porosity plots show that vortex chambers with a sufficient number of gas inlet slots have to be used to guarantee a uniform gas distribution and particle bed. Lastly, the flexibility of particle segregation in vortex chambers with respect to the gas flow rate is demonstrated.« less

Planetary Atmosphere and Surfaces Chamber (PASC): A Platform to Address Various Challenges in Astrobiology

NASA Astrophysics Data System (ADS)

Mateo-Marti, Eva

2014-08-01

The study of planetary environments of astrobiological interest has become a major challenge. Because of the obvious technical and economical limitations on in situ planetary exploration, laboratory simulations are one of the most feasible research options to make advances both in planetary science and in developing a consistent description of the origin of life. With this objective in mind, we applied vacuum technology to the design of versatile vacuum chambers devoted to the simulation of planetary atmospheres' conditions. These vacuum chambers are able to simulate atmospheres and surface temperatures representative of the majority of planetary objects, and they are especially appropriate for studying the physical, chemical and biological changes induced in a particular sample by in situ irradiation or physical parameters in a controlled environment. Vacuum chambers are a promising potential tool in several scientific and technological fields, such as engineering, chemistry, geology and biology. They also offer the possibility of discriminating between the effects of individual physical parameters and selected combinations thereof. The implementation of our vacuum chambers in combination with analytical techniques was specifically developed to make feasible the in situ physico-chemical characterization of samples. Many wide-ranging applications in astrobiology are detailed herein to provide an understanding of the potential and flexibility of these experimental systems. Instruments and engineering technology for space applications could take advantage of our environment-simulation chambers for sensor calibration. Our systems also provide the opportunity to gain a greater understanding of the chemical reactivity of molecules on surfaces under different environments, thereby leading to a greater understanding of interface processes in prebiotic chemical reactions and facilitating studies of UV photostability and photochemistry on surfaces. Furthermore, the stability and presence of certain minerals on planetary surfaces and the potential habitability of microorganisms under various planetary environmental conditions can be studied using our apparatus. Therefore, these simulation chambers can address multiple different challenging and multidisciplinary astrobiological studies.

Aging of bone marrow mesenchymal stromal/stem cells: Implications on autologous regenerative medicine.

PubMed

Charif, N; Li, Y Y; Targa, L; Zhang, L; Ye, J S; Li, Y P; Stoltz, J F; Han, H Z; de Isla, N

2017-01-01

With their proliferation, differentiation into specific cell types, and secretion properties, mesenchymal stromal/stem cells (MSC) are very interesting tools to be used in regenerative medicine. Bone marrow (BM) was the first MSC source characterized. In the frame of autologous MSC therapy, it is important to detect donor's parameters affecting MSC potency. Age of the donors appears as one parameter that could greatly affect MSC properties. Moreover, in vitro cell expansion is needed to obtain the number of cells necessary for clinical developments. It will lead to in vitro cell aging that could modify cell properties. This review recapitulates several studies evaluating the effect of in vitro and in vivo MSC aging on cell properties.

The atmosphere simulation chamber SAPHIR: a tool for the investigation of photochemistry.

NASA Astrophysics Data System (ADS)

Brauers, T.; Bohn, B.; Johnen, F.-J.; Rohrer, R.; Rodriguez Bares, S.; Tillmann, R.; Wahner, A.

2003-04-01

On the campus of the Forschungszentrum Jülich we constructed SAPHIR (Simulation of Atmospheric PHotochemistry In a large Reaction Chamber) which was accomplished in fall 2001. The chamber consists of a 280-m^3 double-wall Teflon bag of cylindrical shape that is held by a steel frame. Typically 75% of the outside actinic flux (290~nm~--~420~nm) is available inside the chamber. A louvre system allows switching between full sun light and dark within 40 s giving the opportunity to study relaxation processes of the photo chemical system. The SAPHIR chamber is equipped with a comprehensive set of sensitive instruments including the measurements of OH, HO_2, CO, hydrocarbons, aldehydes, nitrogen-oxides and solar radiation. Moreover, the modular concept of SAPHIR allows fast and flexible integration of new instruments and techniques. In this paper we will show the unique and new features of the SAPHIR chamber, namely the clean air supply and high purity water vapor supply providing a wide range of trace gas concentrations being accessible through the experiments. We will also present examples from the first year of SAPHIR experiment showing the scope of application from high quality instrument inter-comparison and kinetic studies to the simulation of complex mixtures of trace gases at ambient concentrations.

Design and laboratory testing of a chamber device to measure total flux of volatile organic compounds from the unsaturated zone under natural conditions.

PubMed

Tillman, Fred D; Smith, James A

2004-11-01

To determine if an aquifer contaminated with volatile organic compounds (VOCs) has potential for natural remediation, all natural processes affecting the fate and transport of VOCs in the subsurface must be identified and quantified. This research addresses the quantification of air-phase volatile organic compounds (VOCs) leaving the unsaturated zone soil gas and entering the atmosphere-including the additional flux provided by advective soil-gas movement induced by barometric pumping. A simple and easy-to-use device for measuring VOC flux under natural conditions is presented. The vertical flux chamber (VFC) was designed using numerical simulations and evaluated in the laboratory. Mass-balance numerical simulations based on continuously stirred tank reactor equations (CSTR) provided information on flux measurement performance of several sampling configurations with the final chamber configuration measuring greater than 96% of model-simulated fluxes. A laboratory device was constructed to evaluate the flux chamber under both diffusion-only and advection-plus-diffusion transport conditions. The flux chamber measured an average of 82% of 15 diffusion-only fluxes and an average of 95% of 15 additional advection-plus-diffusion flux experiments. The vertical flux chamber has the capability of providing reliable measurement of VOC flux from the unsaturated zone under both diffusion and advection transport conditions.

Investigation of the Effect of the Non-uniform Flow Distribution After Compressor of Gas Turbine Engine on Inlet Parameters of the Turbine

NASA Astrophysics Data System (ADS)

Orlov, M. Yu; Lukachev, S. V.; Anisimov, V. M.

2018-01-01

The position of combustion chamber between compressor and turbine and combined action of these elements imply that the working processes of all these elements are interconnected. One of the main requirements of the combustion chamber is the formation of the desirable temperature field at the turbine inlet, which can realize necessary durability of nozzle assembly and blade wheel of the first stage of high-pressure turbine. The method of integrated simulation of combustion chamber and neighboring nodes (compressor and turbine) was developed. On the first stage of the study, this method was used to investigate the influence of non-uniformity of flow distribution, occurred after compressor blades on combustion chamber workflow. The goal of the study is to assess the impact of non-uniformity of flow distribution after the compressor on the parameters before the turbine. The calculation was carried out in a transient case for some operation mode of the engine. The simulation showed that the inclusion of compressor has an effect on combustion chamber workflow and allows us to determine temperature field at the turbine inlet and assesses its durability more accurately. In addition, the simulation with turbine showed the changes in flow velocity distribution and pressure in combustion chamber.

Clinicopathologic findings following intra-articular injection of autologous and allogeneic placentally derived equine mesenchymal stem cells in horses.

PubMed

Carrade, Danielle D; Owens, Sean D; Galuppo, Larry D; Vidal, Martin A; Ferraro, Gregory L; Librach, Fred; Buerchler, Sabine; Friedman, Michael S; Walker, Naomi J; Borjesson, Dori L

2011-04-01

The development of an allogeneic mesenchymal stem cell (MSC) product to treat equine disorders would be useful; however, there are limited in vivo safety data for horses. We hypothesized that the injection of self (autologous) and non-self (related allogeneic or allogeneic) MSC would not elicit significant alterations in physical examination, gait or synovial fluid parameters when injected into the joints of healthy horses. Sixteen healthy horses were used in this study. Group 1 consisted of foals (n = 6), group 2 consisted of their dams (n = 5) and group 3 consisted of half-siblings (n = 5) to group 1 foals. Prior to injection, MSC were phenotyped. Placentally derived MSC were injected into contralateral joints and MSC diluent was injected into a separate joint (control). An examination, including lameness evaluation and synovial fluid analysis, was performed at 0, 24, 48 and 72 h post-injection. MSC were major histocompatibility complex (MHC) I positive, MHC II negative and CD86 negative. Injection of allogeneic MSC did not elicit a systemic response. Local responses such as joint swelling or lameness were minimal and variable. Intra-articular MSC injection elicited marked inflammation within the synovial fluid (as measured by nucleated cell count, neutrophil number and total protein concentration). However, there were no significant differences between the degree and type of inflammation elicited by self and non-self-MSC. The healthy equine joint responds similarly to a single intra-articular injection of autologous and allogeneic MSC. This pre-clinical safety study is an important first step in the development of equine allogeneic stem cell therapies.

Involvement of PI3K and ROCK signaling pathways in migration of bone marrow-derived mesenchymal stem cells through human brain microvascular endothelial cell monolayers.

PubMed

Lin, Mei-Na; Shang, De-Shu; Sun, Wei; Li, Bo; Xu, Xin; Fang, Wen-Gang; Zhao, Wei-Dong; Cao, Liu; Chen, Yu-Hua

2013-06-04

Bone marrow-derived mesenchymal stem cells (MSC) represent an important and easily available source of stem cells for potential therapeutic use in neurological diseases. The entry of circulating cells into the central nervous system by intravenous administration requires, firstly, the passage of the cells across the blood-brain barrier (BBB). However, little is known of the details of MSC transmigration across the BBB. In the present study, we employed an in vitro BBB model constructed using a human brain microvascular endothelial cell monolayer to study the mechanism underlying MSC transendothelial migration. Transmigration assays, transendothelial electrical resistance (TEER) and horseradish peroxidase (HRP) flux assays showed that MSC could transmigrate through human brain microvascular endothelial cell monolayers by a paracellular pathway. Cell fractionation and immunofluorescence assays confirmed the disruption of tight junctions. Inhibition assays showed that a Rho-kinase (ROCK) inhibitor (Y27632) effectively promoted MSC transendothelial migration; conversely, a PI3K inhibitor (LY294002) blocked MSC transendothelial migration. Interestingly, adenovirus-mediated interference with ROCK in MSC significantly increased MSC transendothelial migration, and overexpression of a PI3K dominant negative mutant in MSC cells could block transendothelial migration. Our findings provide clear evidence that the PI3K and ROCK pathways are involved in MSC migration through human brain microvascular endothelial cell monolayers. The information yielded by this study may be helpful in constructing gene-modified mesenchymal stem cells that are able to penetrate the BBB effectively for cell therapy. Copyright © 2013 Elsevier B.V. All rights reserved.

Transduction of Wnt11 promotes mesenchymal stem cell transdifferentiation into cardiac phenotypes.

PubMed

He, Zhisong; Li, Hongxia; Zuo, Shi; Pasha, Zeeshan; Wang, Yigang; Yang, Yueting; Jiang, Wenping; Ashraf, Muhammad; Xu, Meifeng

2011-10-01

Transplantation of mesenchymal stem cells (MSCs) has emerged as a potential treatment for ischemic heart repair. Previous studies have suggested that Wnt11 plays a critical role in cardiac specification and morphogenesis. In this study, we examined whether transduction of Wnt11 directly increases MSC differentiation into cardiac phenotypes. MSCs harvested from rat bone marrow were transduced with both Wnt11 and green fluorescent protein (GFP) (MSC(Wnt11)) using the murine stem cell virus (pMSCV) retroviral expression system; control cells were only GFP-transfected (MSC(Null)). Compared with control cells, MSC(Wnt11) was shown to have higher expression of Wnt11 by immunofluorescence, real-time polymerase chain reaction, and western blotting. MSC(Wnt11) shows a higher expression of cardiac-specific genes, including GATA-4, brain natriuretic peptide (BNP), islet-1, and α-actinin, after being cultured with cardiomyocytes (CMs) isolated from ventricles of neonatal (1-3 day) SD rats. Some MSC(Wnt11) were positive for α-actinin when MSCs were cocultured with native CMs for 7 days. Electron microscopy further confirmed the appearance of sarcomeres in MSC(Wnt11). Connexin 43 was found between GFP-positive MSCs and neonatal rat CMs labeled with red fluorescent probe PKH26. The transdifferentiation rate was significantly higher in MSC(Wnt11) than in MSC(Null), as assessed by flow cytometry. Functional studies indicated that the differentiation of MSC(Wnt11) was diminished by knockdown of GATA-4 with GATA-4-siRNA. Transduction of Wnt11 into MSCs increases their differentiation into CMs by upregulating GATA-4.

β1 Integrins Mediate Attachment of Mesenchymal Stem Cells to Cartilage Lesions

PubMed Central

Zwolanek, Daniela; Flicker, Magdalena; Kirstätter, Elisabeth; Zaucke, Frank; van Osch, Gerjo J.V.M.; Erben, Reinhold G.

2015-01-01

Abstract Mesenchymal stem cells (MSC) may have great potential for cell-based therapies of osteoarthritis. However, after injection in the joint, only few cells adhere to defective articular cartilage and contribute to cartilage regeneration. Little is known about the molecular mechanisms of MSC attachment to defective articular cartilage. Here, we developed an ex vivo attachment system, using rat osteochondral explants with artificially created full-thickness cartilage defects in combination with genetically labeled MSC isolated from bone marrow of human placental alkaline phosphatase transgenic rats. Binding of MSC to full-thickness cartilage lesions was improved by serum, but not hyaluronic acid, and was dependent on the presence of divalent cations. Additional in vitro tests showed that rat MSC attach, in a divalent cation-dependent manner, to collagen I, collagen II, and fibronectin, but not to collagen XXII or cartilage oligomeric matrix protein (COMP). RGD peptides partially blocked the adhesion of MSC to fibronectin in vitro and to cartilage lesions ex vivo. Furthermore, the attachment of MSC to collagen I and II in vitro and to cartilage lesions ex vivo was almost completely abolished in the presence of a β1 integrin blocking antibody. In conclusion, our data suggest that attachment of MSC to ex vivo full-thickness cartilage lesions is almost entirely β1 integrin-mediated, whereby both RGD- and collagen-binding integrins are involved. These findings suggest a key role of integrins during MSC attachment to defective cartilage and may pave the way for improved MSC-based therapies in the future. PMID:26309781

Mesenchymal Stem Cell-Conditioned Medium Reduces Disease Severity and Immune Responses in Inflammatory Arthritis.

PubMed

Kay, Alasdair G; Long, Grace; Tyler, George; Stefan, Andrei; Broadfoot, Stephen J; Piccinini, Anna M; Middleton, Jim; Kehoe, Oksana

2017-12-21

We evaluated the therapeutic potential of mesenchymal stem cell-conditioned medium (CM-MSC) as an alternative to cell therapy in an antigen-induced model of arthritis (AIA). Disease severity and cartilage loss were evaluated by histopathological analysis of arthritic knee joints and immunostaining of aggrecan neoepitopes. Cell proliferation was assessed for activated and naïve CD4+ T cells from healthy mice following culture with CM-MSC or co-culture with MSCs. T cell polarization was analysed in CD4+ T cells isolated from spleens and lymph nodes of arthritic mice treated with CM-MSC or MSCs. CM-MSC treatment significantly reduced knee-joint swelling, histopathological signs of AIA, cartilage loss and suppressed TNFα induction. Proliferation of CD4+ cells from spleens of healthy mice was not affected by CM-MSC but reduced when cells were co-cultured with MSCs. In the presence of CM-MSC or MSCs, increases in IL-10 concentration were observed in culture medium. Finally, CD4+ T cells from arthritic mice treated with CM-MSC showed increases in FOXP3 and IL-4 expression and positively affected the Treg:Th17 balance in the tissue. CM-MSC treatment reduces cartilage damage and suppresses immune responses by reducing aggrecan cleavage, enhancing Treg function and adjusting the Treg:Th17 ratio. CM-MSC may provide an effective cell-free therapy for inflammatory arthritis.

Human Umbilical Cord Mesenchymal Stem Cell Exosomes Enhance Angiogenesis Through the Wnt4/β-Catenin Pathway

PubMed Central

Zhang, Bin; Wu, Xiaodan; Zhang, Xu; Sun, Yaoxiang; Yan, Yongmin; Shi, Hui; Zhu, Yanhua; Wu, Lijun; Pan, Zhaoji; Zhu, Wei

2015-01-01

Human umbilical cord mesenchymal stem cells (hucMSCs) and their exosomes have been considered as potential therapeutic tools for tissue regeneration; however, the underlying mechanisms are still not well understood. In this study, we isolated and characterized the exosomes from hucMSCs (hucMSC-Ex) and demonstrated that hucMSC-Ex promoted the proliferation, migration, and tube formation of endothelial cells in a dose-dependent manner. Furthermore, we demonstrated that hucMSC-Ex promoted wound healing and angiogenesis in vivo by using a rat skin burn model. We discovered that hucMSC-Ex promoted β-catenin nuclear translocation and induced the increased expression of proliferating cell nuclear antigen, cyclin D3, N-cadherin, and β-catenin and the decreased expression of E-cadherin. The activation of Wnt/β-catenin is critical in the induction of angiogenesis by hucMSC-Ex, which could be reversed by β-catenin inhibitor ICG-001. Wnt4 was delivered by hucMSC-Ex, and the knockdown of Wnt4 in hucMSC-Ex abrogated β-catenin nuclear translocation in endothelial cells. The in vivo proangiogenic effects were also inhibited by interference of Wnt4 expression in hucMSC-Ex. Taken together, these results suggest that hucMSC-Ex-mediated Wnt4 induces β-catenin activation in endothelial cells and exerts proangiogenic effects, which could be an important mechanism for cutaneous wound healing. PMID:25824139

Crew report. [on Skylab altitude simulation tests

NASA Technical Reports Server (NTRS)

Bobko, K. J.; Crippen, R. L.; Thornton, W. E.

1973-01-01

A 56-day chamber simulation of Skylab was successfully completed. The atmosphere (5 psi, 70 percent oxygen, 30 percent nitrogen, 5 mm carbon dioxide) and medical features including a 21-day pre- and 18-day post-test medical protocols were closely simulated. No apparent crew health problems were induced by the atmosphere, semiclosed environment, or other test features; and no appreciable crew degradation appeared over this period. The chamber and associated systems performed without major problems.

Performance-enhanced mesenchymal stem cells via intracellular delivery of steroids

NASA Astrophysics Data System (ADS)

Ankrum, James A.; Dastidar, Riddhi G.; Ong, Joon Faii; Levy, Oren; Karp, Jeffrey M.

2014-04-01

Inadequate immunomodulatory potency of mesenchymal stem cells (MSC) may limit their therapeutic efficacy. We report glucocorticoid steroids augment MSC expression and activity of indoleamine-2,3-dioxygenase (IDO), a primary mediator of MSC immunomodulatory function. This effect depends on signaling through the glucocorticoid receptor and is mediated through up-regulation of FOXO3. Treatment of MSCs with glucocorticoids, budesonide or dexamethasone, enhanced IDO expression following IFN-γ stimulation in multiple donors and was able to restore IDO expression in over-passaged MSCs. As IDO enhancement was most notable when cells were continuously exposed to budesonide, we engineered MSC with budesonide loaded PLGA microparticles. MSC efficiently internalized budesonide microparticles and exhibited 4-fold enhanced IDO activity compared to budesonide preconditioned and naïve MSC, resulting in a 2-fold improvement in suppression of stimulated peripheral blood mononuclear cells in an IDO-dependent manner. Thus, the augmentation of MSC immune modulation may abrogate challenges associated with inadequate potency and enhance their therapeutic efficacy.

Performance-enhanced mesenchymal stem cells via intracellular delivery of steroids

PubMed Central

Ankrum, James A.; Dastidar, Riddhi G.; Ong, Joon Faii; Levy, Oren; Karp, Jeffrey M.

2014-01-01

Inadequate immunomodulatory potency of mesenchymal stem cells (MSC) may limit their therapeutic efficacy. We report glucocorticoid steroids augment MSC expression and activity of indoleamine-2,3-dioxygenase (IDO), a primary mediator of MSC immunomodulatory function. This effect depends on signaling through the glucocorticoid receptor and is mediated through up-regulation of FOXO3. Treatment of MSCs with glucocorticoids, budesonide or dexamethasone, enhanced IDO expression following IFN-γ stimulation in multiple donors and was able to restore IDO expression in over-passaged MSCs. As IDO enhancement was most notable when cells were continuously exposed to budesonide, we engineered MSC with budesonide loaded PLGA microparticles. MSC efficiently internalized budesonide microparticles and exhibited 4-fold enhanced IDO activity compared to budesonide preconditioned and naïve MSC, resulting in a 2-fold improvement in suppression of stimulated peripheral blood mononuclear cells in an IDO-dependent manner. Thus, the augmentation of MSC immune modulation may abrogate challenges associated with inadequate potency and enhance their therapeutic efficacy. PMID:24717973

Generation of immunosuppressive mesenchymal stem cells in allogeneic human serum.

PubMed

Le Blanc, Katarina; Samuelsson, Håkan; Lönnies, Lena; Sundin, Mikael; Ringdén, Olle

2007-10-27

Mesenchymal stem cells (MSC) may be used to treat acute graft-versus-host disease and for tissue repair. In vitro expansion of MSC has been achieved in the presence of fetal calf serum (FCS). For safety and regulatory reasons, we explored if FCS could be replaced by human blood group AB serum. Proliferation and fold increase of MSC was higher in the presence of AB-serum, compared to FCS. Similar to cells generated in FCS media, MSC from AB-serum media were more than 95% positive for CD90, CD105 and human leukocyte antigen (HLA) class I, and negative for hematopoietic and endothelial markers CD14, CD31, CD34, CD45, and CD80. HLA class II expression was higher in MSC generated in AB-serum, but decreased with higher passage numbers. MSC generated in AB-serum suppressed lymphocyte proliferation in mixed lymphocyte cultures and after stimulation with phytohemagglutinin. MSC expanded in AB-serum and FCS have similar in vitro properties.

Genetically engineered suicide gene in mesenchymal stem cells using a Tet-On system for anaplastic thyroid cancer.

PubMed

Kalimuthu, Senthilkumar; Oh, Ji Min; Gangadaran, Prakash; Zhu, Liya; Lee, Ho Won; Jeon, Yong Hyun; Jeong, Shin Young; Lee, Sang-Woo; Lee, Jaetae; Ahn, Byeong-Cheol

2017-01-01

Anaplastic thyroid cancer (ATC) is the most aggressive malignancy of the thyroid, during which undifferentiated tumors arise from the thyroid follicular epithelium. ATC has a very poor prognosis due to its aggressive behavior and poor response to conventional therapies. Gene-directed enzyme/prodrug therapy using genetically engineered mesenchymal stromal cells (MSC) is a promising therapeutic strategy. The doxycycline (DOX)-controlled Tet inducible system is the most widely utilized regulatory system and could be a useful tool for therapeutic gene-based therapies. For example, use a synthetic "tetracycline-on" switch system to control the expression of the therapeutic gene thymidine kinase, which converts prodrugs to active drugs. The aim of this study was to develop therapeutic MSCs, harboring an inducible suicide gene, and to validate therapeutic gene expression using optical molecular imaging of ATC. We designed the Tet-On system using a retroviral vector expressing herpes simplex virus thymidine kinase (HSV1-sr39TK) with dual reporters (eGFP-Fluc2). Mouse bone marrow-derived mesenchymal stromal cells (BM-MSC) were transduced using this system with (MSC-Tet-TK/Fluc2) or without (MSC-TK/Fluc) the Tet-On system. Transduced cells were screened and characterized. Engineered MSCs were co-cultured with ATC (CAL62/Rluc) cells in the presence of the prodrug ganciclovir (GCV) and stimulated with DOX. The efficiency of cell killing monitored by assessing Rluc (CAL62/Rluc) and Fluc (MSC-Tet-TK/Fluc and MSC-TK/Fluc) activities using IVIS imaging. Fluc activity increased in MSC-Tet-TK/Fluc cells in a dose dependent manner following DOX treatment (R2 = 0.95), whereas no signal was observed in untreated cells. eGFP could also be visualized after induction with DOX, and the HSV1-TK protein could be detected by western blotting. In MSC-TK/Fluc cells, the Fluc activity increased with increasing cell number (R2 = 0.98), and eGFP could be visualized by fluorescence microscopy. The Fluc activity and cell viability of MSC-Tet-TK/Fluc and MSC-TK/Fluc cells decreased significantly following GCV treatment. A bystander effect of the therapeutic cells confirmed in co-cultures of CAL62 cells, an anaplastic thyroid cancer cell line, with either MSC-Tet-TK/Fluc cells or MSC-TK/Fluc cells. The Rluc activity in MSC-Tet-TK/Fluc co-cultures, derived from the CAL62/Rluc cells, decreased significantly with GCV treatment of DOX treated cultures, whereas no significant changes were observed in untreated cultures. In addition, the Fluc activity of MSC-Tet-TK/Fluc cells also decreased significantly with DOX treatment whereas no signal was present in untreated cultures. A bystander effect also be demonstrated in co-cultures with MSC-TK/Fluc cells and CAL62/Rluc; both the Rluc activity and the Fluc activity were significantly decreased following GCV treatment. We have successfully developed a Tet-On system of gene-directed enzyme/prodrug delivery using MSCs. We confirmed the therapeutic bystander effect in CAL62/Rluc cells with respect to MSC-Tet-TK/Fluc and MSC-TK/Fluc cells after GCV treatment with and without DOX. Our results confirm the therapeutic efficiency of a suicide gene, with or without the Tet-On system, for ATC therapy. In addition, our findings provide an innovative therapeutic approach for using the Tet-On system to eradicate tumors by simple, repeated administration of MSC-Tet-TK/Fluc cells with DOX and GCV.

Photosynthetic Activity and Adaptation Capacities of Lichens and Cyanobacteria to Martian Surface Conditions

NASA Astrophysics Data System (ADS)

De Vera, Jean-Pierre; Schulze-Makuch, D.; Khan, A.; Lorek, A.; Koncz, A.; Stivaletta, N.; Möhlmann, D.; Spohn, T.

2012-05-01

We observed an increase in photosynthetic activity in the lichen Pleopsidium chlorophanum but a strong negative effect on the photosynthetic activity of endolithic cyanobacteria when subjected for 34 days to environmental stresses likely to be encountered in semi-protected habitats on the Martian surface. Stresses were simulated in a Mars Simulation Chamber (MSC) and included high UV fluxes, low temperatures, low water activity, high atmospheric CO2 concentrations, and an atmospheric pressure of about 6 mbar. P. chlorophanum is an extremophile: it lives in very cold, dry, high-altitude habitats which are Earth's best approximation of the Martian surface. Our lichen samples came from North Victoria Land in Antarctica whereas the investigated samples of cyanobacteria came from tropic regions in the Sahara. Three samples of each group of organisms were exposed uninterruptedly to simulated conditions (as above) of the naked, unprotected Martian surface for 34 days, receiving the full Martian solar spectrum (200 - 2500 nm) for a cumulative UV dose of 6343.6 kJm-2. For a second sample set - containing also three lichen thalli and three endolithic cyanobacteria communities - the cumulative (34-day) UV dose was reduced to 268.8 kJm-2, to reasonably simulate the amount the microorganisms might receive in (semi-) protected surface sites (e.g., fissures, cracks and micro-caves within rocks or permafrost soil). In the 'unprotected' experiment it was unclear if the lichen was still actively photosynthesizing but still clear that the cyanobacteria were affected. However, under 'protected site' conditions, the cyanobacteria had no clear photosynthetic response under and after simulated Martian conditions but the lichen not only survived and remained photosynthetically active, it even adapted physiologically by increasing its photosynthetic activity over 34 days. Comparison with other Mars simulation experiments on exposure platforms in space and in the laboratory with other investigated species show results of remarkable survival rates and maintained photosynthesizing activity which strongly supports the interconnected notions (1) that terrestrial life most likely can adapt physiologically to live on Mars (hence justifying stringent measures to prevent human activities from contaminating/infecting Mars with terrestrial organisms); (2) that in searching for extant life on Mars we should focus on "protected" habitats; and (3) that early-originating (Noachian Period) indigenous Martian life might still survive in such habitats despite Mars' cooling and drying during the last 4 billion years.

Water Impact Test and Simulation of a Composite Energy Absorbing Fuselage Section

NASA Technical Reports Server (NTRS)

Fasanella, Edwin L.; Jackson, Karen E.; Sparks, Chad; Sareen, Ashish

2003-01-01

In March 2002, a 25-ft/s vertical drop test of a composite fuselage section was conducted onto water. The purpose of the test was to obtain experimental data characterizing the structural response of the fuselage section during water impact for comparison with two previous drop tests that were performed onto a rigid surface and soft soil. For the drop test, the fuselage section was configured with ten 100-lb. lead masses, five per side, that were attached to seat rails mounted to the floor. The fuselage section was raised to a height of 10-ft. and dropped vertically into a 15-ft. diameter pool filled to a depth of 3.5-ft. with water. Approximately 70 channels of data were collected during the drop test at a 10-kHz sampling rate. The test data were used to validate crash simulations of the water impact that were developed using the nonlinear, explicit transient dynamic codes, MSC.Dytran and LS-DYNA. The fuselage structure was modeled using shell and solid elements with a Lagrangian mesh, and the water was modeled with both Eulerian and Lagrangian techniques. The fluid-structure interactions were executed using the fast general coupling in MSC.Dytran and the Arbitrary Lagrange-Euler (ALE) coupling in LS-DYNA. Additionally, the smooth particle hydrodynamics (SPH) meshless Lagrangian technique was used in LS-DYNA to represent the fluid. The simulation results were correlated with the test data to validate the modeling approach. Additional simulation studies were performed to determine how changes in mesh density, mesh uniformity, fluid viscosity, and failure strain influence the test-analysis correlation.

RANS Simulation (Actuator Disk Model[ADM]) of the NREL Phase VI wind turbine modeled as MHK Turbine

DOE Data Explorer

Javaherchi, Teymour

2016-06-08

Attached are the .cas and .dat files for the Reynolds Averaged Navier-Stokes (RANS) simulation of a single lab-scaled DOE RM1 turbine implemented in ANSYS FLUENT CFD-package. In this case study the flow field around and in the wake of the NREL Phase VI wind turbine, modeled is MHK turbine, is simulated using Actuator Disk Model (a.k.a Porous Media) by solving RANS equations coupled with a turbulence closure model. It should be highlighted that in this simulation the actual geometry of the rotor blade is not modeled. The effect of turbine rotating blades are modeled using the Actuator Disk Theory (see the stated section of attached M.Sc. thesis for more details).

An electromagnetic compressive force by cell exciter stimulates chondrogenic differentiation of bone marrow-derived mesenchymal stem cells.

PubMed

Park, Sang-Hyug; Sim, Woo Young; Park, Sin Wook; Yang, Sang Sik; Choi, Byung Hyune; Park, So Ra; Park, Kwideok; Min, Byoung-Hyun

2006-11-01

In this study, we present a biological micro-electromechanical system and its application to the chondrogenic differentiation of rabbit bone marrow-derived mesenchymal stem cells (MSCs). Actuated by an electromagnetic force, the micro cell exciter was designed to deliver a cyclic compressive load (CCL) with various magnitudes. Two major parts in the system are an actuator and a cartridge-type chamber. The former has a permanent magnet and coil, and the latter is equipped with 7 sample dishes and 7 metal caps. Mixed with a 2.4% alginate solution, the alginate/MSC layers were positioned in the sample dishes; the caps contained chondrogenic defined medium without transforming growth factor-beta (TGF-beta). Once powered, the actuator coil-derived electromagnetic force pulled the metal caps down, compressing the samples. The cyclic load was given at 1-Hz frequency for 10 min twice a day. Samples in the dishes without a cap served as a control. The samples were analyzed at 3, 5, and 7 days after stimulation for cell viability, biochemical assays, histologic features, immunohistochemistry, and gene expression of the chondrogenic markers. Applied to the alginate/MSC layer, the CCL system enhanced the synthesis of cartilage-specific matrix proteins and the chondrogenic markers, such as aggrecan, type II collagen, and Sox9. We found that the micromechanically exerted CCL by the cell exciter was very effective in enhancing the chondrogenic differentiation of MSCs, even without using exogenous TGF-beta.

An oil-based model of inhalation anesthetic uptake and elimination.

PubMed

Loughlin, P J; Bowes, W A; Westenskow, D R

1989-08-01

An oil-based model was developed as a physical simulation of inhalation anesthetic uptake and elimination. It provides an alternative to animal models in testing the performance of anesthesia equipment. A 7.5-1 water-filled manometer simulates pulmonary mechanics. Nitrogen and carbon dioxide flowing into the manometer simulate oxygen consumption and carbon dioxide production. Oil-filled chambers (180 ml and 900 ml) simulate the uptake and washout of halothane by the vessel-rich and muscle tissue groups. A 17.2-1 air-filled chamber simulates uptake by the lung group. Gas circulates through the chambers (3.7, 13.8, and 25 l/min) to simulate the transport of anesthetic to the tissues by the circulatory system. Results show that during induction and washout, the rate of rise in endtidal halothane fraction simulated by the model parallels that measured in patients. The model's end-tidal fraction changes correctly with changes in cardiac output and alveolar ventilation. The model has been used to test anesthetic controllers and to evaluate gas sensors, and should be useful in teaching principles underlying volatile anesthetic uptake.

Biodistribution and Immunogenicity of Allogeneic Mesenchymal Stem Cells in a Rat Model of Intraarticular Chondrocyte Xenotransplantation.

PubMed

Marquina, Maribel; Collado, Javier A; Pérez-Cruz, Magdiel; Fernández-Pernas, Pablo; Fafián-Labora, Juan; Blanco, Francisco J; Máñez, Rafael; Arufe, María C; Costa, Cristina

2017-01-01

Xenogeneic chondrocytes and allogeneic mesenchymal stem cells (MSC) are considered a potential source of cells for articular cartilage repair. We here assessed the immune response triggered by xenogeneic chondrocytes when injected intraarticularly, as well as the immunoregulatory effect of allogeneic bone marrow-derived MSC after systemic administration. To this end, a discordant xenotransplantation model was established by injecting three million porcine articular chondrocytes (PAC) into the femorotibial joint of Lewis rats and monitoring the immune response. First, the fate of MSC injected using various routes was monitored in an in vivo imaging system. The biodistribution revealed a dependency on the injection route with MSC injected intravenously (i.v.) succumbing early after 24 h and MSC injected intraperitoneally (i.p.) lasting locally for at least 5 days. Importantly, no migration of MSC to the joint was detected in rats previously injected with PAC. MSC were then administered either i.v. 1 week before PAC injection or i.p. 3 weeks after to assess their immunomodulatory function on humoral and adaptive immune parameters. Anti-PAC IgM and IgG responses were detected in all PAC-injected rats with a peak at week 2 postinjection and reactivity remaining above baseline levels by week 18. IgG2a and IgG2b were the predominant and long-lasting IgG subtypes. By contrast, no anti-MSC antibody response was detected in the cohort injected with MSC only, but infusion of MSC before PAC injection temporarily augmented the anti-PAC antibody response. Consistent with a cellular immune response to PAC in PAC-injected rats, cytokine/chemokine profiling in serum by antibody array revealed a distinct pattern relative to controls characterized by elevation of multiple markers at week 2, as well as increases in proliferation in draining lymph nodes. Notably, systemic administration of allogeneic MSC under the described conditions did not diminish the immune response. IL-2 measurements in cocultures of rat peripheral blood lymphocytes with PAC indicated that PAC injection induced some T-cell hyporesponsiveness that was not enhanced in the cohorts additionally receiving MSC. Thus, PAC injected intraarticularly in Lewis rats induced a cellular and humoral immune response that was not counteracted by the systemic administration of allogeneic MSC under the described conditions.

Comparative outcomes of open-wedge high tibial osteotomy with platelet-rich plasma alone or in combination with mesenchymal stem cell treatment: a prospective study.

PubMed

Koh, Yong-Gon; Kwon, Oh-Ryong; Kim, Yong-Sang; Choi, Yun-Jin

2014-11-01

This study compared the clinical results and second-look arthroscopic findings of patients undergoing open-wedge high tibial osteotomy (HTO) for varus deformity, with or without mesenchymal stem cell (MSC) therapy. This prospective, comparative observational study was designed to evaluate the effectiveness of MSC therapy. The patients were divided into 2 groups: HTO with platelet-rich plasma (PRP) injection only (n = 23) or HTO in conjunction with MSC therapy and PRP injection (n = 21). Prospective evaluations of both groups were performed using the Lysholm score, Knee Injury and Osteoarthritis Outcome Score (KOOS), and a visual analog scale (VAS) score for pain. Second-look arthroscopy was carried out in all patients at the time of metal removal. The patients in the MSC-PRP group showed significantly greater improvements in the KOOS subscales for pain (PRP only, 74.0 ± 5.7; MSC-PRP, 81.2 ± 6.9; P < .001) and symptoms (PRP only, 75.4 ± 8.5; MSC-PRP, 82.8 ± 7.2; P = .006) relative to the PRP-only group. Although the mean Lysholm score was similarly improved in both groups (PRP only, 80.6 ± 13.5; MSC-PRP, 84.7 ± 16.2; P = .357), the MSC-PRP group showed a significantly greater improvement in the VAS pain score (PRP only, 16.2 ± 4.6; MSC-PRP, 10.2 ± 5.7; P < .001). There were no differences in the preoperative (PRP only, varus 2.8° ± 1.7°; MSC-PRP, varus 3.4° ± 3.0°; P = .719) and postoperative (PRP only, valgus 9.8° ± 2.4°; MSC-PRP, valgus 8.7° ± 2.3°; P = .678) femorotibial angles or weight-bearing lines between the groups. Arthroscopic evaluation, at plate removal, showed that partial or even fibrocartilage coverage was achieved in 50% of the MSC-PRP group patients but in only 10% of the patients in the PRP-only group (P < .001). MSC therapy, in conjunction with HTO, mildly improved cartilage healing and showed good clinical results in some KOOS subscores and the VAS pain score compared with PRP only. Level II, prospective comparative study. Copyright © 2014 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

Mesenchymal Stem Cells from Fetal Heart Attenuate Myocardial Injury after Infarction: An In Vivo Serial Pinhole Gated SPECT-CT Study in Rats

PubMed Central

Garikipati, Venkata Naga Srikanth; Jadhav, Sachin; Pal, Lily; Prakash, Prem; Dikshit, Madhu; Nityanand, Soniya

2014-01-01

Mesenchymal stem cells (MSC) have emerged as a potential stem cell type for cardiac regeneration after myocardial infarction (MI). Recently, we isolated and characterized mesenchymal stem cells derived from rat fetal heart (fC-MSC), which exhibited potential to differentiate into cardiomyocytes, endothelial cells and smooth muscle cells in vitro. In the present study, we investigated the therapeutic efficacy of intravenously injected fC-MSC in a rat model of MI using multi-pinhole gated SPECT-CT system. fC-MSC were isolated from the hearts of Sprague Dawley (SD) rat fetuses at gestation day 16 and expanded ex vivo. One week after induction of MI, 2×106 fC-MSC labeled with PKH26 dye (n = 6) or saline alone (n = 6) were injected through the tail vein of the rats. Initial in vivo tracking of 99mTc-labeled fC-MSC revealed a focal uptake of cells in the anterior mid-ventricular region of the heart. At 4 weeks of fC-MSC administration, the cells labeled with PKH26 were located in abundance in infarct/peri-infarct region and the fC-MSC treated hearts showed a significant increase in left ventricular ejection fraction and a significant decrease in the end diastolic volume, end systolic volume and left ventricular myo-mass in comparison to the saline treated group. In addition, fC-MSC treated hearts had a significantly better myocardial perfusion and attenuation in the infarct size, in comparison to the saline treated hearts. The engrafted PKH26-fC-MSC expressed cardiac troponin T, endothelial CD31 and smooth muscle sm-MHC, suggesting their differentiation into all major cells of cardiovascular lineage. The fC-MSC treated hearts demonstrated an up-regulation of cardio-protective growth factors, anti-fibrotic and anti-apoptotic molecules, highlighting that the observed left ventricular functional recovery may be due to secretion of paracrine factors by fC-MSC. Taken together, our results suggest that fC-MSC therapy may be a new therapeutic strategy for MI and multi-pinhole gated SPECT-CT system may be a useful tool to evaluate cardiac perfusion, function and cell tracking after stem cell therapy in acute myocardial injury setting. PMID:24971627

Biodistribution and Immunogenicity of Allogeneic Mesenchymal Stem Cells in a Rat Model of Intraarticular Chondrocyte Xenotransplantation

PubMed Central

Marquina, Maribel; Collado, Javier A.; Pérez-Cruz, Magdiel; Fernández-Pernas, Pablo; Fafián-Labora, Juan; Blanco, Francisco J.; Máñez, Rafael; Arufe, María C.; Costa, Cristina

2017-01-01

Xenogeneic chondrocytes and allogeneic mesenchymal stem cells (MSC) are considered a potential source of cells for articular cartilage repair. We here assessed the immune response triggered by xenogeneic chondrocytes when injected intraarticularly, as well as the immunoregulatory effect of allogeneic bone marrow-derived MSC after systemic administration. To this end, a discordant xenotransplantation model was established by injecting three million porcine articular chondrocytes (PAC) into the femorotibial joint of Lewis rats and monitoring the immune response. First, the fate of MSC injected using various routes was monitored in an in vivo imaging system. The biodistribution revealed a dependency on the injection route with MSC injected intravenously (i.v.) succumbing early after 24 h and MSC injected intraperitoneally (i.p.) lasting locally for at least 5 days. Importantly, no migration of MSC to the joint was detected in rats previously injected with PAC. MSC were then administered either i.v. 1 week before PAC injection or i.p. 3 weeks after to assess their immunomodulatory function on humoral and adaptive immune parameters. Anti-PAC IgM and IgG responses were detected in all PAC-injected rats with a peak at week 2 postinjection and reactivity remaining above baseline levels by week 18. IgG2a and IgG2b were the predominant and long-lasting IgG subtypes. By contrast, no anti-MSC antibody response was detected in the cohort injected with MSC only, but infusion of MSC before PAC injection temporarily augmented the anti-PAC antibody response. Consistent with a cellular immune response to PAC in PAC-injected rats, cytokine/chemokine profiling in serum by antibody array revealed a distinct pattern relative to controls characterized by elevation of multiple markers at week 2, as well as increases in proliferation in draining lymph nodes. Notably, systemic administration of allogeneic MSC under the described conditions did not diminish the immune response. IL-2 measurements in cocultures of rat peripheral blood lymphocytes with PAC indicated that PAC injection induced some T-cell hyporesponsiveness that was not enhanced in the cohorts additionally receiving MSC. Thus, PAC injected intraarticularly in Lewis rats induced a cellular and humoral immune response that was not counteracted by the systemic administration of allogeneic MSC under the described conditions. PMID:29163532

Canine Platelet Lysate Is Inferior to Fetal Bovine Serum for the Isolation and Propagation of Canine Adipose Tissue- and Bone Marrow-Derived Mesenchymal Stromal Cells

PubMed Central

Russell, Keith A.; Gibson, Thomas W. G.; Chong, Andrew; Co, Carmon; Koch, Thomas G.

2015-01-01

Background Mesenchymal stromal cells (MSC) are increasingly investigated for their clinical utility in dogs. Fetal bovine serum (FBS) is a common culture supplement used for canine MSC expansion. However, FBS content is variable, its clinical use carries risk of an immune response, and its cost is increasing due to global demand. Platelet lysate (PL) has proven to be a suitable alternative to FBS for expansion of human MSC. Hypothesis and Objectives We hypothesized that canine adipose tissue (AT) and bone marrow (BM) MSC could be isolated and expanded equally in PL and FBS at conventionally-used concentrations with differentiation of these MSC unaffected by choice of supplement. Our objectives were to evaluate the use of canine PL in comparison with FBS at four stages: 1) isolation, 2) proliferation, 3) spontaneous differentiation, and 4) directed differentiation. Results 1) Medium with 10% PL was unable to isolate MSC. 2) MSC, initially isolated in FBS-supplemented media, followed a dose-dependent response with no significant difference between PL and FBS cultures at up to 20% (AT) or 30% (BM) enrichment. Beyond these respective peaks, proliferation fell in PL cultures only, while a continued dose-dependent proliferation response was noted in FBS cultures. 3) Further investigation indicated PL expansion culture was inducing spontaneous adipogenesis in concentrations as low as 10% and as early as 4 days in culture. 4) MSC isolated in FBS, but expanded in either FBS or PL, maintained ability to undergo directed adipogenesis and osteogenesis, but not chondrogenesis. Conclusions/Significance Canine PL did not support establishment of MSC colonies from AT and BM, nor expansion of MSC, which appear to undergo spontaneous adipogenesis in response to PL exposure. In vivo studies are warranted to determine if concurrent use of MSC with any platelet-derived products such as platelet-rich plasma are associated with synergistic, neutral or antagonistic effects. PMID:26353112

Identification of IL-1β and LPS as optimal activators of monolayer and alginate-encapsulated mesenchymal stromal cell immunomodulation using design of experiments and statistical methods.

PubMed

Gray, Andrea; Maguire, Timothy; Schloss, Rene; Yarmush, Martin L

2015-01-01

Induction of therapeutic mesenchymal stromal cell (MSC) function is dependent upon activating factors present in diseased or injured tissue microenvironments. These functions include modulation of macrophage phenotype via secreted molecules including prostaglandin E2 (PGE2). Many approaches aim to optimize MSC-based therapies, including preconditioning using soluble factors and cell immobilization in biomaterials. However, optimization of MSC function is usually inefficient as only a few factors are manipulated in parallel. We utilized fractional factorial design of experiments to screen a panel of 6 molecules (lipopolysaccharide [LPS], polyinosinic-polycytidylic acid [poly(I:C)], interleukin [IL]-6, IL-1β, interferon [IFN]-β, and IFN-γ), individually and in combinations, for the upregulation of MSC PGE2 secretion and attenuation of macrophage secretion of tumor necrosis factor (TNF)-α, a pro-inflammatory molecule, by activated-MSC conditioned medium (CM). We used multivariable linear regression (MLR) and analysis of covariance to determine differences in functions of optimal factors on monolayer MSCs and alginate-encapsulated MSCs (eMSCs). The screen revealed that LPS and IL-1β potently activated monolayer MSCs to enhance PGE2 production and attenuate macrophage TNF-α. Activation by LPS and IL-1β together synergistically increased MSC PGE2, but did not synergistically reduce macrophage TNF-α. MLR and covariate analysis revealed that macrophage TNF-α was strongly dependent on the MSC activation factor, PGE2 level, and macrophage donor but not MSC culture format (monolayer versus encapsulated). The results demonstrate the feasibility and utility of using statistical approaches for higher throughput cell analysis. This approach can be extended to develop activation schemes to maximize MSC and MSC-biomaterial functions prior to transplantation to improve MSC therapies. © 2015 American Institute of Chemical Engineers.

Articular cartilage-derived cells hold a strong osteogenic differentiation potential in comparison to mesenchymal stem cells in vitro

DOE Office of Scientific and Technical Information (OSTI.GOV)

Salamon, Achim, E-mail: achim.salamon@med.uni-rostock.de; Jonitz-Heincke, Anika, E-mail: anika.jonitz@med.uni-rostock.de; Adam, Stefanie, E-mail: stefanie.adam@med.uni-rostock.de

Cartilaginous matrix-degenerative diseases like osteoarthritis (OA) are characterized by gradual cartilage erosion, and also by increased presence of cells with mesenchymal stem cell (MSC) character within the affected tissues. Moreover, primary chondrocytes long since are known to de-differentiate in vitro and to be chondrogenically re-differentiable. Since both findings appear to conflict with each other, we quantitatively assessed the mesenchymal differentiation potential of OA patient cartilage-derived cells (CDC) towards the osteogenic and adipogenic lineage in vitro and compared it to that of MSC isolated from adipose tissue (adMSC) of healthy donors. We analyzed expression of MSC markers CD29, CD44, CD105, andmore » CD166, and, following osteogenic and adipogenic induction in vitro, quantified their expression of osteogenic and adipogenic differentiation markers. Furthermore, CDC phenotype and proliferation were monitored. We found that CDC exhibit an MSC CD marker expression pattern similar to adMSC and a similar increase in proliferation rate during osteogenic differentiation. In contrast, the marked reduction of proliferation observed during adipogenic differentiation of adMSC was absent in CDC. Quantification of differentiation markers revealed a strong osteogenic differentiation potential for CDC, however almost no capacity for adipogenic differentiation. Since in the pathogenesis of OA, cartilage degeneration coincides with high bone turnover rates, the high osteogenic differentiation potential of OA patient-derived CDC may affect clinical therapeutic regimens aiming at autologous cartilage regeneration in these patients. - Highlights: • We analyze the mesenchymal differentiation capacity of cartilage-derived cells (CDC). • CDC express mesenchymal stem cell (MSC) markers CD29, CD44, CD105, and CD166. • CDC and MSC proliferation is reduced in adipogenesis and increased in osteogenesis. • Adipogenic differentiation is virtually absent in CDC, but strong in MSC. • Osteogenic differentiation is significantly stronger for CDC than for MSC.« less

Clinical-scale expansion of mesenchymal stromal cells: a large banking experience.

PubMed

Lechanteur, Chantal; Briquet, Alexandra; Giet, Olivier; Delloye, Olivier; Baudoux, Etienne; Beguin, Yves

2016-05-20

Mesenchymal stromal cells (MSC) are largely investigated in clinical trials aiming to control inappropriate immune reactions (GVHD, Crohn's disease, solid organ transplantation). As the percentage of MSC precursors in bone marrow is very low, these must be expanded in vitro to obtain therapeutic cell doses. We describe here the constitution of an allogeneic human third-party MSC bank from screened healthy volunteer donors in compliance with quality specifications and ISCT-release criteria and report follow-up of different aspects of this activity since 2007. 68 clinical-grade large-scale MSC cultures were completed and analyzed. The whole process was described, including volunteer donor screening, bone marrow collection, mononuclear cell isolation and expansion over 4 weeks, harvesting, cryopreservation, release, administration and quality controls of the cells (including microbiology, phenotype, and potency assays). From 59 validated donors, 68 cultures were completed (mean of final yields: 886 × 10(6) cells/culture) and a total of 464 MSC aliquots have been produced and stored in liquid nitrogen (mean of 132.8 × 10(6) cells/bag). Each MSC batch underwent extensive testing to verify its conformity with EBMT and ISCT release criteria and was individually validated. As of June 1 2015, 314 bags have been released and infused to patients included in 6 different clinical protocols. All thawed MSC units satisfied to release criteria and no infusion-related toxicity was reported. In conclusion, despite low passage cultures, we have been able to create an allogeneic "off-the-shelf" MSC bank with a large number of frozen aliquots and report here an efficient clinical-grade MSC banking activity in place for more than 7 years. Our challenge now is to produce MSC in compliance with good manufacturing practices (GMP) as, in the meantime, MSC have become considered as advanced therapy medicinal products (ATMP). Another significant challenge remains the development of relevant potency assay.

Directly auto-transplanted mesenchymal stem cells induce bone formation in a ceramic bone substitute in an ectopic sheep model

PubMed Central

Boos, Anja M; Loew, Johanna S; Deschler, Gloria; Arkudas, Andreas; Bleiziffer, Oliver; Gulle, Heinz; Dragu, Adrian; Kneser, Ulrich; Horch, Raymund E; Beier, Justus P

2011-01-01

Abstract Bone tissue engineering approaches increasingly focus on the use of mesenchymal stem cells (MSC). In most animal transplantation models MSC are isolated and expanded before auto cell transplantation which might be critical for clinical application in the future. Hence this study compares the potential of directly auto-transplanted versus in vitro expanded MSC with or without bone morphogenetic protein-2 (BMP-2) to induce bone formation in a large volume ceramic bone substitute in the sheep model. MSC were isolated from bone marrow aspirates and directly auto-transplanted or expanded in vitro and characterized using fluorescence activated cell sorting (FACS) and RT-PCR analysis before subcutaneous implantation in combination with BMP-2 and β-tricalcium phosphate/hydroxyapatite (β-TCP/HA) granules. Constructs were explanted after 1 to 12 weeks followed by histological and RT-PCR evaluation. Sheep MSC were CD29+, CD44+ and CD166+ after selection by Ficoll gradient centrifugation, while directly auto-transplanted MSC-populations expressed CD29 and CD166 at lower levels. Both, directly auto-transplanted and expanded MSC, were constantly proliferating and had a decreasing apoptosis over time in vivo. Directly auto-transplanted MSC led to de novo bone formation in a heterotopic sheep model using a β-TCP/HA matrix comparable to the application of 60 μg/ml BMP-2 only or implantation of expanded MSC. Bone matrix proteins were up-regulated in constructs following direct auto-transplantation and in expanded MSC as well as in BMP-2 constructs. Up-regulation was detected using immunohistology methods and RT-PCR. Dense vascularization was demonstrated by CD31 immunohistology staining in all three groups. Ectopic bone could be generated using directly auto-transplanted or expanded MSC with β-TCP/HA granules alone. Hence BMP-2 stimulation might become dispensable in the future, thus providing an attractive, clinically feasible approach to bone tissue engineering. PMID:20636333

Computation of Neutral Gas Flow from a Hall Thruster into a Vacuum Chamber

DTIC Science & Technology

2002-10-18

try to quantify these effects, the direct simulation Monte Carlo method is applied to model a cold flow of xenon gas expanding from a Hall thruster into...a vacuum chamber. The simulations are performed for the P5 Hall thruster operating in a large vacuum tank at the University of Michigan. Comparison

Human platelet lysate in mesenchymal stromal cell expansion according to a GMP grade protocol: a cell factory experience.

PubMed

Becherucci, Valentina; Piccini, Luisa; Casamassima, Serena; Bisin, Silvia; Gori, Valentina; Gentile, Francesca; Ceccantini, Riccardo; De Rienzo, Elena; Bindi, Barbara; Pavan, Paola; Cunial, Vanessa; Allegro, Elisa; Ermini, Stefano; Brugnolo, Francesca; Astori, Giuseppe; Bambi, Franco

2018-05-02

The use of platelet lysate (PL) for the ex-vivo expansion of mesenchymal stromal/stem cells (MSCs) was initially proposed by Doucet et al. in 2005, as an alternative to animal serum. Moreover, regulatory authorities discourage the use of fetal bovine serum (FBS) or other animal derivatives, to avoid risk of zoonoses and xenogeneic immune reactions. Even if many studies investigated PL composition, there still are some open issues related to its use in ex-vivo MSC expansion, especially according to good manufacturing practice (GMP) grade protocols. As an authorized cell factory, we report our experience using standardized PL produced by Azienda Ospedaliero Universitaria Meyer Transfusion Service for MSC expansion according to a GMP grade clinical protocol. As suggested by other authors, we performed an in-vitro test on MSCs versus MSCs cultured with FBS that still represents the best way to test PL batches. We compared 12 MSC batches cultured with DMEM 5% PL with similar batches cultured with DMEM 10% FBS, focusing on the MSC proliferation rate, MSC surface marker expression, MSC immunomodulatory and differentiation potential, and finally MSC relative telomere length. Results confirmed the literature data as PL increases cell proliferation without affecting the MSC immunophenotype, immunomodulatory potential, differentiation potential and relative telomere length. PL can be considered a safe alternative to FBS for ex-vivo expansion of MSC according to a GMP grade protocol. Our experience confirms the literature data: a large number of MSCs for clinical applications can be obtained by expansion with PL, without affecting the MSC main features. Our experience underlines the benefits of a close collaboration between the PL producers (transfusion service) and the end users (cell factory) in a synergy of skills and experiences that can lead to standardized PL production.

Circulating microRNA signature as liquid-biopsy to monitor lung cancer in low-dose computed tomography screening.

PubMed

Sestini, Stefano; Boeri, Mattia; Marchiano, Alfonso; Pelosi, Giuseppe; Galeone, Carlotta; Verri, Carla; Suatoni, Paola; Sverzellati, Nicola; La Vecchia, Carlo; Sozzi, Gabriella; Pastorino, Ugo

2015-10-20

Liquid biopsies can detect biomarkers carrying information on the development and progression of cancer. We demonstrated that a 24 plasma-based microRNA signature classifier (MSC) was capable of increasing the specificity of low dose computed tomography (LDCT) in a lung cancer screening trial. In the present study, we tested the prognostic performance of MSC, and its ability to monitor disease status recurrence in LDCT screening-detected lung cancers.Between 2000 and 2010, 3411 heavy smokers enrolled in two screening programmes, underwent annual or biennial LDCT. During the first five years of screening, 84 lung cancer patients were classified according to one of the three MSC levels of risk: high, intermediate or low. Kaplan-Meier survival analysis was performed according to MSC and clinico-pathological information. Follow-up MSC analysis was performed on longitudinal plasma samples (n = 100) collected from 31 patients before and after surgical resection.Five-year survival was 88.9% for low risk, 79.5% for intermediate risk and 40.1% for high risk MSC (p = 0.001). The prognostic power of MSC persisted after adjusting for tumor stage (p = 0.02) and when the analysis was restricted to LDCT-detected cases after exclusion of interval cancers (p < 0.001). The MSC risk level decreased after surgery in 76% of the 25 high-intermediate subjects who remained disease free, whereas in relapsing patients an increase of the MSC risk level was observed at the time of detection of second primary tumor or metastatic progression.These results encourage exploiting the MSC test for lung cancer monitoring in LDCT screening for lung cancer.

Combined enzyme/prodrug treatment by genetically engineered AT-MSC exerts synergy and inhibits growth of MDA-MB-231 induced lung metastases.

PubMed

Matuskova, Miroslava; Kozovska, Zuzana; Toro, Lenka; Durinikova, Erika; Tyciakova, Silvia; Cierna, Zuzana; Bohovic, Roman; Kucerova, Lucia

2015-04-09

Metastatic spread of tumor cells remains a serious problem in cancer treatment. Gene-directed enzyme/prodrug therapy mediated by tumor-homing genetically engineered mesenchymal stromal cells (MSC) represents a promising therapeutic modality for elimination of disseminated cells. Efficacy of gene-directed enzyme/prodrug therapy can be improved by combination of individual systems. We aimed to define the combination effect of two systems of gene therapy mediated by MSC, and evaluate the ability of systemically administered genetically engineered mesenchymal stromal cells to inhibit the growth of experimental metastases derived from human breast adenocarcinoma cells MDA-MB-231/EGFP. Human adipose tissue-derived mesenchymal stromal cells (AT-MSC) were retrovirally transduced with fusion yeast cytosine deaminase::uracil phosphoribosyltransferase (CD::UPRT) or with Herpes simplex virus thymidine kinase (HSVtk). Engineered MSC were cocultured with tumor cells in the presence of prodrugs 5-fluorocytosin (5-FC) and ganciclovir (GCV). Combination effect of these enzyme/prodrug approaches was calculated. SCID/bg mice bearing experimental lung metastases were treated with CD::UPRT-MSC, HSVtk-MSC or both in combination in the presence of respective prodrug(s). Treatment efficiency was evaluated by EGFP-positive cell detection by flow cytometry combined with real-time PCR quantification of human cells in mouse organs. Results were confirmed by histological and immunohistochemical examination. We demonstrated various extent of synergy depending on tested cell line and experimental setup. The strongest synergism was observed on breast cancer-derived cell line MDA-MB-231/EGFP. Systemic administration of CD::UPRT-MSC and HSVtk-MSC in combination with 5-FC and GCV inhibited growth of MDA-MB-231 induced lung metastases. Combined gene-directed enzyme/prodrug therapy mediated by MSC exerted synergic cytotoxic effect and resulted in high therapeutic efficacy in vivo.

Canine and Equine Mesenchymal Stem Cells Grown in Serum Free Media Have Altered Immunophenotype.

PubMed

Clark, Kaitlin C; Kol, Amir; Shahbenderian, Salpi; Granick, Jennifer L; Walker, Naomi J; Borjesson, Dori L

2016-04-01

Mesenchymal stem cell (MSC) therapy is being increasingly used to treat dogs and horses with naturally-occurring diseases. However these animals also serve as critical large animal models for ongoing translation of cell therapy products to the human market. MSC manufacture for clinical use mandates improvement in cell culture systems to meet demands for higher MSC numbers and removal of xeno-proteins (i.e. fetal bovine serum, FBS). While serum-free media (SFM) is commercially available, its affects on MSC phenotype and immunomodulatory functions are not fully known. The objective of this study was to determine if specific MSC culture conditions, MSC expansion in HYPERFlasks® or MSC expansion in a commercially available SFM, would alter MSC proliferation, phenotype or immunomodulatory properties in vitro. MSCs cultured in HYPERFlasks® were similar in phenotype, proliferative capacity and immunomodulatory functions to MSCs grown in standard flasks however MSC yield was markedly increased. HYPERFlasks® therefore provide a viable option to generate greater cell numbers in a streamlined manner. Canine and equine MSCs expanded in SFM displayed similar proliferation, surface phenotype and inhibitory effect on lymphocyte proliferation in vitro. However, MSCs cultured in the absence of FBS secreted significantly less PGE2, and were significantly less able to inhibit IFNγ secretion by activated T-cells. Immunomodulatory functions altered by expansion in SFM were species dependent. Unlike equine MSCs, in canine adipose-derived MSCs, the inhibition of lymphocyte proliferation was not principally modulated by PGE2. The removal of FBS from both canine and equine MSC culture systems resulted in altered immunomodulatory properties in vitro and warrants further investigation prior to moving towards FBS-free culture conditions.

Intra-articular administration of xenogeneic neonatal Mesenchymal Stromal Cells early after meniscal injury down-regulates metalloproteinase gene expression in synovium and prevents cartilage degradation in a rabbit model of osteoarthritis.

PubMed

Saulnier, N; Viguier, E; Perrier-Groult, E; Chenu, C; Pillet, E; Roger, T; Maddens, S; Boulocher, C

2015-01-01

The anti-inflammatory and anti-catabolic effects of neonatal Mesenchymal Stromal Cell (MSC) were investigated in a xenogeneic model of mild osteoarthritis (OA). The paracrine properties of MSC on synoviocytes were further investigated in vitro. OA was induced by medial meniscal release (MMR) in 30 rabbit knees. A single early (day 3) or delayed (day 15) intra-articular (IA) injection of MSC isolated from equine Umbilical Cord Wharton's jelly (UC-MSC) was performed. Rabbits were euthanized on days 15 or 56. OA grading was performed and gene expression of inflammatory cytokines and metalloproteinases was measured in synovial tissue. Paracrine effects of UC-MSC were investigated using UC-conditioned vs control medium on rabbit primary synoviocytes stimulated with interleukin 1 beta in vitro. No adverse local or systemic responses were observed clinically after xenogeneic UC-MSC injection. At study end point, cartilage fibrillation was lower in early treatment than in delayed treatment group. Cellular infiltrate was observed in the synovium of both UC-MSC groups. OA synovium exhibited a reduced expression of metalloproteinases-1, -3, -13 in the early cell-treated group at d56. In vitro, UC-conditioned medium exerted anti-inflammatory and anti-catabolic effects on synoviocytes exposed to pro-inflammatory stimulus. Early IA injection of equine UC-MSC was effective in preventing OA signs in rabbit knees following MMR. UC-MSC target the synovium and modulate the gene expression pattern of synoviocytes to promote an anti-catabolic environment. This confirms the synovium is a major target and mediator of MSC therapy, modulating the expression of matrix-degrading enzymes. Copyright © 2014 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

Reconstruction of cartilage with clonal mesenchymal stem cell-acellular dermal matrix in cartilage defect model in nonhuman primates.

PubMed

Ma, Anlun; Jiang, Li; Song, Lijun; Hu, Yanxin; Dun, Hao; Daloze, Pierre; Yu, Yonglin; Jiang, Jianyuan; Zafarullah, Muhammad; Chen, Huifang

2013-07-01

Articular cartilage defects are commonly associated with trauma, inflammation and osteoarthritis. Mesenchymal stem cell (MSC)-based therapy is a promising novel approach for repairing articular cartilage. Direct intra-articular injection of uncommitted MSCs does not regenerate high-quality cartilage. This study explored utilization of a new three-dimensional, selected chondrogenic clonal MSC-loaded monkey acellular dermal matrix (MSC-ADM) scaffold to repair damaged cartilage in an experimental model of knee joint cartilage defect in Cynomolgus monkeys. MSCs were characterized for cell size, cell yield, phenotypes, proliferation and chondrogenic differentiation capacity. Chondrogenic differentiation assays were performed at different MSC passages by sulfated glycosaminoglycans (sGAG), collagen, and fluorescence activated cell sorter (FACS) analysis. Selected chondrogenic clonal MSCs were seeded onto ADM scaffold with the sandwich model and MSC-loaded ADM grafts were analyzed by confocal microscopy and scanning electron microscopy. Cartilage defects were treated with normal saline, clonal MSCs and clonal MSC-ADM grafts, respectively. The clinical parameters, and histological and immunohistochemical examinations were evaluated at weeks 8, 16, 24 post-treatment, respectively. Polyclonal and clonal MSCs could differentiate into the chondrogenic lineage after stimulation with suitable chondrogenic factors. They expressed mesenchymal markers and were negative for hematopoietic markers. Articular cartilage defects were considerably improved and repaired by selected chondrogenic clonal MSC-based treatment, particularly, in MSC-ADM-treated group. The histological scores in MSC-ADM-treated group were consistently higher than those of other groups. Our results suggest that selected chondrogenic clonal MSC-loaded ADM grafts could improve the cartilage lesions in Cynomolgus monkey model, which may be applicable for repairing similar human cartilage defects. Copyright © 2013 Elsevier B.V. All rights reserved.

Chondrogenesis in a hyaluronic acid scaffold: comparison between chondrocytes and MSC from bone marrow and adipose tissue.

PubMed

Jakobsen, Rune B; Shahdadfar, Aboulghassem; Reinholt, Finn P; Brinchmann, Jan E

2010-10-01

Treatment of focal lesions of the articular cartilage of the knee using chondrocytes in a hyaluronic acid (HA) scaffold is already being investigated in clinical trials. An alternative may be to use mesenchymal stem cells (MSC). We have compared articular chondrocytes with MSC from human bone marrow (BM) and adipose tissue (AT), all cultured in HA scaffolds, for their ability to express genes and synthesize proteins associated with chondrogenesis. The cells were expanded in monolayer cultures. After seeding into the scaffold, the chondrocytes were maintained in medium, while the two MSC populations were given a chondrogenic differentiation medium. Chondrogenesis was assessed by real-time RT-PCR for chondrocyte-associated genes, by immunohistochemistry and by ELISA for collagens in the supernatant. Redifferentiation of the dedifferentiated chondrocytes in the HA scaffold was shown by a modest increase in type II collagen mRNA (COL2A1) and reduction in COL1A1. BM-MSC expressed 600-fold higher levels of COL2A1 than chondrocytes after 3 weeks in the scaffold. The levels of aggrecan (AGC1) and COL1A1 were similar for chondrocyte and BM-MSC scaffold cultures, while COL10A1 was higher in the BM-MSC. AT-MSC expressed levels of COL2A1 and COL1A1 similar to chondrocytes, but less AGC1 and COL10A1. Surprisingly, little collagen II protein was observed in the scaffold. Instead, collagen II was found in the culture medium. Chondrogenesis in HA scaffolds was more efficient using BM-MSC than AT-MSC or chondrocytes. Some of the secreted collagen II escaped entrapment in the extracellular space and was detected in the culture medium.

Stem cell conditioned medium improves acute lung injury in mice: in vivo evidence for stem cell paracrine action.

PubMed

Ionescu, Lavinia; Byrne, Roisin N; van Haaften, Tim; Vadivel, Arul; Alphonse, Rajesh S; Rey-Parra, Gloria J; Weissmann, Gaia; Hall, Adam; Eaton, Farah; Thébaud, Bernard

2012-12-01

Mortality and morbidity of acute lung injury and acute respiratory distress syndrome remain high because of the lack of pharmacological therapies to prevent injury or promote repair. Mesenchymal stem cells (MSCs) prevent lung injury in various experimental models, despite a low proportion of donor-derived cell engraftment, suggesting that MSCs exert their beneficial effects via paracrine mechanisms. We hypothesized that soluble factors secreted by MSCs promote the resolution of lung injury in part by modulating alveolar macrophage (AM) function. We tested the therapeutic effect of MSC-derived conditioned medium (CdM) compared with whole MSCs, lung fibroblasts, and fibroblast-CdM. Intratracheal MSCs and MSC-CdM significantly attenuated lipopolysaccharide (LPS)-induced lung neutrophil influx, lung edema, and lung injury as assessed by an established lung injury score. MSC-CdM increased arginase-1 activity and Ym1 expression in LPS-exposed AMs. In vivo, AMs from LPS-MSC and LPS-MSC CdM lungs had enhanced expression of Ym1 and decreased expression of inducible nitric oxide synthase compared with untreated LPS mice. This suggests that MSC-CdM promotes alternative macrophage activation to an M2 "healer" phenotype. Comparative multiplex analysis of MSC- and fibroblast-CdM demonstrated that MSC-CdM contained several factors that may confer therapeutic benefit, including insulin-like growth factor I (IGF-I). Recombinant IGF-I partially reproduced the lung protective effect of MSC-CdM. In summary, MSCs act through a paracrine activity. MSC-CdM promotes the resolution of LPS-induced lung injury by attenuating lung inflammation and promoting a wound healing/anti-inflammatory M2 macrophage phenotype in part via IGF-I.

Stem cell conditioned medium improves acute lung injury in mice: in vivo evidence for stem cell paracrine action

PubMed Central

Ionescu, Lavinia; Byrne, Roisin N.; van Haaften, Tim; Vadivel, Arul; Alphonse, Rajesh S.; Rey-Parra, Gloria J.; Weissmann, Gaia; Hall, Adam; Eaton, Farah

2012-01-01

Mortality and morbidity of acute lung injury and acute respiratory distress syndrome remain high because of the lack of pharmacological therapies to prevent injury or promote repair. Mesenchymal stem cells (MSCs) prevent lung injury in various experimental models, despite a low proportion of donor-derived cell engraftment, suggesting that MSCs exert their beneficial effects via paracrine mechanisms. We hypothesized that soluble factors secreted by MSCs promote the resolution of lung injury in part by modulating alveolar macrophage (AM) function. We tested the therapeutic effect of MSC-derived conditioned medium (CdM) compared with whole MSCs, lung fibroblasts, and fibroblast-CdM. Intratracheal MSCs and MSC-CdM significantly attenuated lipopolysaccharide (LPS)-induced lung neutrophil influx, lung edema, and lung injury as assessed by an established lung injury score. MSC-CdM increased arginase-1 activity and Ym1 expression in LPS-exposed AMs. In vivo, AMs from LPS-MSC and LPS-MSC CdM lungs had enhanced expression of Ym1 and decreased expression of inducible nitric oxide synthase compared with untreated LPS mice. This suggests that MSC-CdM promotes alternative macrophage activation to an M2 “healer” phenotype. Comparative multiplex analysis of MSC- and fibroblast-CdM demonstrated that MSC-CdM contained several factors that may confer therapeutic benefit, including insulin-like growth factor I (IGF-I). Recombinant IGF-I partially reproduced the lung protective effect of MSC-CdM. In summary, MSCs act through a paracrine activity. MSC-CdM promotes the resolution of LPS-induced lung injury by attenuating lung inflammation and promoting a wound healing/anti-inflammatory M2 macrophage phenotype in part via IGF-I. PMID:23023971

SU-F-18C-09: Assessment of OSL Dosimeter Technology in the Validation of a Monte Carlo Radiation Transport Code for CT Dosimetry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carver, D; Kost, S; Pickens, D

Purpose: To assess the utility of optically stimulated luminescent (OSL) dosimeter technology in calibrating and validating a Monte Carlo radiation transport code for computed tomography (CT). Methods: Exposure data were taken using both a standard CT 100-mm pencil ionization chamber and a series of 150-mm OSL CT dosimeters. Measurements were made at system isocenter in air as well as in standard 16-cm (head) and 32-cm (body) CTDI phantoms at isocenter and at the 12 o'clock positions. Scans were performed on a Philips Brilliance 64 CT scanner for 100 and 120 kVp at 300 mAs with a nominal beam width ofmore » 40 mm. A radiation transport code to simulate the CT scanner conditions was developed using the GEANT4 physics toolkit. The imaging geometry and associated parameters were simulated for each ionization chamber and phantom combination. Simulated absorbed doses were compared to both CTDI{sub 100} values determined from the ion chamber and to CTDI{sub 100} values reported from the OSLs. The dose profiles from each simulation were also compared to the physical OSL dose profiles. Results: CTDI{sub 100} values reported by the ion chamber and OSLs are generally in good agreement (average percent difference of 9%), and provide a suitable way to calibrate doses obtained from simulation to real absorbed doses. Simulated and real CTDI{sub 100} values agree to within 10% or less, and the simulated dose profiles also predict the physical profiles reported by the OSLs. Conclusion: Ionization chambers are generally considered the standard for absolute dose measurements. However, OSL dosimeters may also serve as a useful tool with the significant benefit of also assessing the radiation dose profile. This may offer an advantage to those developing simulations for assessing radiation dosimetry such as verification of spatial dose distribution and beam width.« less

The role of simulation chambers in the development of spectroscopic techniques: campaigns at EUPHORE

NASA Astrophysics Data System (ADS)

Ródenas, Milagros; Muñoz, Amalia; Euphore Team

2016-04-01

Simulation chambers represent a very useful tool for the study of chemical reactions and their products, but also to characterize instruments. The development of spectroscopic techniques throughout the last decades has benefited from tests and intercomparison exercises carried out in chambers. In fact, instruments can be exposed to various controlled atmospheric scenarios that account for different environmental conditions, eliminating the uncertainties associated to fluctuations of the air mass, which must be taken into account when extrapolating results to the real conditions. Hence, a given instrument can be characterized by assessing its precision, accuracy, detection limits, time response and potential interferences in the presence of other chemical compounds, aerosols, etc. This implies that the instrument can be calibrated and validated, which allows to enhance the features of the instrument. Moreover, chambers are also the scenario of intercomparison trials, permitting multiple instruments to sample from the same well-mixed air mass simultaneously. An overview of different campaigns to characterize and/or intercompare spectroscopic techniques that have taken place in simulation chambers will be given; in particular, those carried out at EUPHORE (two twin domes, 200 m3 each, Spain), where various intercomparison exercises have been deployed under the frame of European projects (e.g. TOXIC, FIONA, PSOA campaigns supported by EUROCHAMP-II). With the common aim of measuring given compounds (e.g. HONO, NO2, OH, glyoxal, m-glyoxal, etc), an important number of spectroscopic instruments and institutions have been involved in chamber experiments, having the chance to intercompare among them and also with other non-spectroscopic systems (e.g. monitors, cromatographs, etc) or model simulations.

Enhanced neuro-therapeutic potential of Wharton's Jelly-derived mesenchymal stem cells in comparison with bone marrow mesenchymal stem cells culture.

PubMed

Drela, Katarzyna; Lech, Wioletta; Figiel-Dabrowska, Anna; Zychowicz, Marzena; Mikula, Michał; Sarnowska, Anna; Domanska-Janik, Krystyna

2016-04-01

Substantial inconsistencies in mesenchymal stem (stromal) cell (MSC) therapy reported in early translational and clinical studies may indicate need for selection of the proper cell population for any particular therapeutic purpose. In the present study we have examined stromal stem cells derived either from umbilical cord Wharton's Jelly (WJ-MSC) or bone marrow (BM-MSC) of adult, healthy donors. The cells characterized in accordance with the International Society for Cellular Therapy (ISCT) indications as well as other phenotypic and functional parameters have been compared under strictly controlled culture conditions. WJ-MSC, in comparison with BM-MSC, exhibited a higher proliferation rate, a greater expansion capability being additionally stimulated under low-oxygen atmosphere, enhanced neurotrophic factors gene expression and spontaneous tendency toward a neural lineage differentiation commitment confirmed by protein and gene marker induction. Our data suggest that WJ-MSC may represent an example of immature-type "pre-MSC," where a substantial cellular component is embryonic-like, pluripotent derivatives with the default neural-like differentiation. These cells may contribute in different extents to nearly all classical MSC populations adversely correlated with the age of cell donors. Our data suggest that neuro-epithelial markers, like nestin, stage specific embryonic antigens-4 or α-smooth muscle actin expressions, may serve as useful indicators of MSC culture neuro-regeneration-associated potency. Copyright © 2016 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

Simulated airplane headache: a proxy towards identification of underlying mechanisms.

PubMed

Bui, Sebastian Bao Dinh; Petersen, Torben; Poulsen, Jeppe Nørgaard; Gazerani, Parisa

2017-12-01

Airplane Headache (AH) occurs during flights and often appears as an intense, short lasting headache during take-off or landing. Reports are limited on pathological mechanisms underlying the occurrence of this headache. Proper diagnosis and treatments would benefit from identification of potential pathways involved in AH pathogenesis. This study aimed at providing a simulated airplane headache condition as a proxy towards identification of its underlying mechanisms. Fourteen participants including 7 volunteers suffering from AH and 7 healthy matched controls were recruited after meeting the diagnostic and safety criteria based on an approved study protocol. Simulation of AH was achieved by entering a pressure chamber with similar characteristics of an airplane flight. Selected potential biomarkers including salivary prostaglandin E 2 (PGE 2 ), cortisol, facial thermo-images, blood pressure, pulse, and saturation pulse oxygen (SPO) were defined and values were collected before, during and after flight simulation in the pressure chamber. Salivary samples were analyzed with ELISA techniques, while data analysis and statistical tests were handled with SPSS version 22.0. All participants in the AH-group experienced a headache attack similar to AH experience during flight. The non-AH-group did not experience any headaches. Our data showed that the values for PGE 2 , cortisol and SPO were significantly different in the AH-group in comparison with the non-AH-group during the flight simulation in the pressure chamber. The pressure chamber proved useful not only to provoke AH-like attack but also to study potential biomarkers for AH in this study. PGE 2 , and cortisol levels together with SPO presented dysregulation during the simulated AH-attack in affected individuals compared with healthy controls. Based on these findings we propose to use pressure chamber as a model to induce AH, and thus assess new potential biomarkers for AH in future studies.

Velocity Plume Profiles for Hall Thrusters Using Laser Diagnostic

DTIC Science & Technology

2010-06-01

53 Collecting LIF Using Fiber Optics .............................................................................58 Vacuum ...54 Figure 40. Etalon Issue Through Vacuum Chamber Window [25]. ................................. 55 Figure 41. Collimator with Adapter in a...Methodology Facility Set-up Vacuum Chamber Testing took place within a vacuum chamber located at the AFIT Space Propulsion Analysis and System Simulation

46 CFR 160.028-4 - Approval and production tests.

Code of Federal Regulations, 2013 CFR

2013-10-01

... the chamber and bore dimensions is not required. (2) Inspections and tests by an independent... the chamber and bore dimensions of the pistol. (2) Fire a dummy cartridge simulating a normal signal....009 (4) Recheck the chamber and bore dimensions. (5) The pistol must fire the signal properly, must...

46 CFR 160.028-4 - Approval and production tests.

Code of Federal Regulations, 2011 CFR

2011-10-01

... the chamber and bore dimensions is not required. (2) Inspections and tests by an independent... the chamber and bore dimensions of the pistol. (2) Fire a dummy cartridge simulating a normal signal....009 (4) Recheck the chamber and bore dimensions. (5) The pistol must fire the signal properly, must...

46 CFR 160.028-4 - Approval and production tests.

Code of Federal Regulations, 2014 CFR

2014-10-01

... the chamber and bore dimensions is not required. (2) Inspections and tests by an independent... the chamber and bore dimensions of the pistol. (2) Fire a dummy cartridge simulating a normal signal....009 (4) Recheck the chamber and bore dimensions. (5) The pistol must fire the signal properly, must...

46 CFR 160.028-4 - Approval and production tests.

Code of Federal Regulations, 2012 CFR

2012-10-01

... the chamber and bore dimensions is not required. (2) Inspections and tests by an independent... the chamber and bore dimensions of the pistol. (2) Fire a dummy cartridge simulating a normal signal....009 (4) Recheck the chamber and bore dimensions. (5) The pistol must fire the signal properly, must...

Polarity effects and apparent ion recombination in microionization chambers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, Jessica R., E-mail: miller@humonc.wisc.edu; Hooten, Brian D.; Micka, John A.

Purpose: Microchambers demonstrate anomalous voltage-dependent polarity effects. Existing polarity and ion recombination correction factors do not account for these effects. As a result, many commercial microchamber models do not meet the specification of a reference-class ionization chamber as defined by the American Association of Physicists in Medicine. The purpose of this investigation is to determine the cause of these voltage-dependent polarity effects. Methods: A series of microchamber prototypes were produced to isolate the source of the voltage-dependent polarity effects. Parameters including ionization-chamber collecting-volume size, stem and cable irradiation, chamber assembly, contaminants, high-Z materials, and individual chamber components were investigated. Measurementsmore » were performed with electrodes coated with graphite to isolate electrode conductivity. Chamber response was measured as the potential bias of the guard electrode was altered with respect to the collecting electrode, through the integration of additional power supplies. Ionization chamber models were also simulated using COMSOL Multiphysics software to investigate the effect of a potential difference between electrodes on electric field lines and collecting volume definition. Results: Investigations with microchamber prototypes demonstrated that the significant source of the voltage-dependent polarity effects was a potential difference between the guard and collecting electrodes of the chambers. The voltage-dependent polarity effects for each prototype were primarily isolated to either the guard or collecting electrode. Polarity effects were reduced by coating the isolated electrode with a conductive layer of graphite. Polarity effects were increased by introducing a potential difference between the electrodes. COMSOL simulations further demonstrated that for a given potential difference between electrodes, the collecting volume of the chamber changed as the applied voltage was altered, producing voltage-dependent polarity effects in the chamber response. Ionization chamber measurements and COMSOL simulations demonstrated an inverse relationship between the chamber collecting volume size and the severity of voltage-dependent polarity effects on chamber response. The effect of a given potential difference on chamber polarity effects was roughly ten times greater for microchambers as compared to Farmer-type chambers. Stem and cable irradiations, chamber assembly, contaminants, and high-Z materials were not found to be a significant source of the voltage-dependent polarity effects. Conclusions: A potential difference between the guard and collecting electrodes was found to be the primary source of the voltage-dependent polarity effects demonstrated by microchambers. For a given potential difference between electrodes, the relative change in the collecting volume is smaller for larger-volume chambers, illustrating why these polarity effects are not seen in larger-volume chambers with similar guard and collecting electrode designs. Thus, for small-volume chambers, it is necessary to reduce the potential difference between the guard and collecting electrodes in order to reduce polarity effects for reference dosimetry measurements.« less

A Contact-Based Method for Differentiation of Human Mesenchymal Stem Cells into an Endothelial Cell-Phenotype.

PubMed

Joddar, Binata; Kumar, Shweta Anil; Kumar, Alok

2018-06-01

Adult stem cells such as mesenchymal stem cells (MSC) are known to possess the ability to augment neovascularization processes and are thus widely popular as an autologous source of progenitor cells. However there is a huge gap in our current knowledge of mechanisms involved in differentiating MSC into endothelial cells (EC), essential for lining engineered blood vessels. To fill up this gap, we attempted to differentiate human MSC into EC, by culturing the former onto chemically fixed layers of EC or its ECM, respectively. We expected direct contact of MSC when cultured atop fixed EC or its ECM, would coax the former to differentiate into EC. Results showed that human MSC cultured atop chemically fixed EC or its ECM using EC-medium showed enhanced expression of CD31, a marker for EC, compared to other cases. Further in all human MSC cultured using EC-medium, typically characteristic cobble stone shaped morphologies were noted in comparison to cells cultured using MSC medium, implying that the differentiated cells were sensitive to soluble VEGF supplementation present in the EC-medium. Results will enhance and affect therapies utilizing autologous MSC as a cell source for generating vascular cells to be used in a variety of tissue engineering applications.

Gene expression profiling of human mesenchymal stem cells derived from bone marrow during expansion and osteoblast differentiation.

PubMed

Kulterer, Birgit; Friedl, Gerald; Jandrositz, Anita; Sanchez-Cabo, Fatima; Prokesch, Andreas; Paar, Christine; Scheideler, Marcel; Windhager, Reinhard; Preisegger, Karl-Heinz; Trajanoski, Zlatko

2007-03-12

Human mesenchymal stem cells (MSC) with the capacity to differentiate into osteoblasts provide potential for the development of novel treatment strategies, such as improved healing of large bone defects. However, their low frequency in bone marrow necessitate ex vivo expansion for further clinical application. In this study we asked if MSC are developing in an aberrant or unwanted way during ex vivo long-term cultivation and if artificial cultivation conditions exert any influence on their stem cell maintenance. To address this question we first developed human oligonucleotide microarrays with 30.000 elements and then performed large-scale expression profiling of long-term expanded MSC and MSC during differentiation into osteoblasts. The results showed that MSC did not alter their osteogenic differentiation capacity, surface marker profile, and the expression profiles of MSC during expansion. Microarray analysis of MSC during osteogenic differentiation identified three candidate genes for further examination and functional analysis: ID4, CRYAB, and SORT1. Additionally, we were able to reconstruct the three developmental phases during osteoblast differentiation: proliferation, matrix maturation, and mineralization, and illustrate the activation of the SMAD signaling pathways by TGF-beta2 and BMPs. With a variety of assays we could show that MSC represent a cell population which can be expanded for therapeutic applications.

Exosomes derived from human mesenchymal stem cells confer drug resistance in gastric cancer

PubMed Central

Ji, Runbi; Zhang, Bin; Zhang, Xu; Xue, Jianguo; Yuan, Xiao; Yan, Yongmin; Wang, Mei; Zhu, Wei; Qian, Hui; Xu, Wenrong

2015-01-01

Mesenchymal stem cells (MSCs) play an important role in chemoresistance. Exosomes have been reported to modify cellular phenotype and function by mediating cell-cell communication. In this study, we aimed to investigate whether exosomes derived from MSCs (MSC-exosomes) are involved in mediating the resistance to chemotherapy in gastric cancer and to explore the underlying molecular mechanism. We found that MSC-exosomes significantly induced the resistance of gastric cancer cells to 5-fluorouracil both in vivo and ex vivo. MSC-exosomes antagonized 5-fluorouracil-induced apoptosis and enhanced the expression of multi-drug resistance associated proteins, including MDR, MRP and LRP. Mechanistically, MSC-exosomes triggered the activation of calcium/calmodulin-dependent protein kinases (CaM-Ks) and Raf/MEK/ERK kinase cascade in gastric cancer cells. Blocking the CaM-Ks/Raf/MEK/ERK pathway inhibited the promoting role of MSC-exosomes in chemoresistance. Collectively, MSC-exosomes could induce drug resistance in gastric cancer cells by activating CaM-Ks/Raf/MEK/ERK pathway. Our findings suggest that MSC-exosomes have profound effects on modifying gastric cancer cells in the development of drug resistance. Targeting the interaction between MSC-exosomes and cancer cells may help improve the efficacy of chemotherapy in gastric cancer. PMID:26091251

Exosomes derived from human mesenchymal stem cells confer drug resistance in gastric cancer.

PubMed

Ji, Runbi; Zhang, Bin; Zhang, Xu; Xue, Jianguo; Yuan, Xiao; Yan, Yongmin; Wang, Mei; Zhu, Wei; Qian, Hui; Xu, Wenrong

2015-08-03

Mesenchymal stem cells (MSCs) play an important role in chemoresistance. Exosomes have been reported to modify cellular phenotype and function by mediating cell-cell communication. In this study, we aimed to investigate whether exosomes derived from MSCs (MSC-exosomes) are involved in mediating the resistance to chemotherapy in gastric cancer and to explore the underlying molecular mechanism. We found that MSC-exosomes significantly induced the resistance of gastric cancer cells to 5-fluorouracil both in vivo and ex vivo. MSC-exosomes antagonized 5-fluorouracil-induced apoptosis and enhanced the expression of multi-drug resistance associated proteins, including MDR, MRP and LRP. Mechanistically, MSC-exosomes triggered the activation of calcium/calmodulin-dependent protein kinases (CaM-Ks) and Raf/MEK/ERK kinase cascade in gastric cancer cells. Blocking the CaM-Ks/Raf/MEK/ERK pathway inhibited the promoting role of MSC-exosomes in chemoresistance. Collectively, MSC-exosomes could induce drug resistance in gastric cancer cells by activating CaM-Ks/Raf/MEK/ERK pathway. Our findings suggest that MSC-exosomes have profound effects on modifying gastric cancer cells in the development of drug resistance. Targeting the interaction between MSC-exosomes and cancer cells may help improve the efficacy of chemotherapy in gastric cancer.

Biomimetic chimeric peptide-tethered hydrogels for human mesenchymal stem cell delivery.

PubMed

Shim, Gayong; Kim, Gunwoo; Choi, Junhyeok; Yi, TacGhee; Cho, Yun Kyoung; Song, Sun Uk; Byun, Youngro; Oh, Yu-Kyoung

2015-12-01

Here, we report a chimeric peptide-tethered fibrin hydrogel scaffold for delivery of human mesenchymal stem cells (hMSC). Osteopontin-derived peptide (OP) was used as an hMSC-tethering moiety. OP showed hMSC adhesion properties and enhanced hMSC proliferation. A natural fibrin-binding protein-derived peptide (FBP) was tested for its ability to tether hMSC to the fibrin gel matrix. FBP loading on fibrin gels was 8.2-fold higher than that of a scrambled peptide (scFBP). FBP-loaded fibrin gels were retained at injection sites longer than scFBP-loaded fibrin gels, showing a 15.9-fold higher photon intensity of fluorescent FBP-grafted fibrin gels than fluorescent scFBP-loaded fibrin gels 48 h after injection. On the basis of the fibrin gel-binding properties of FBP and the hMSC-binding and proliferation-supporting properties of OP, we constructed chimeric peptides containing FBP and OP linked with a spacer (FBPsOP). Four days after transplantation, the survival of hMSC in FBPsOP-grafted fibrin gels was 3.9-fold higher than hMSC in fibrin gels alone. Our results suggest the potential of FBPsOP-grafted fibrin gels as a bioactive delivery system for enhanced survival of stem cells. Copyright © 2015 Elsevier B.V. All rights reserved.

Ballistic Deficits for Ionization Chamber Pulses in Pulse Shaping Amplifiers

NASA Astrophysics Data System (ADS)

Kumar, G. Anil; Sharma, S. L.; Choudhury, R. K.

2007-04-01

In order to understand the dependence of the ballistic deficit on the shape of rising portion of the voltage pulse at the input of a pulse shaping amplifier, we have estimated the ballistic deficits for the pulses from a two-electrode parallel plate ionization chamber as well as for the pulses from a gridded parallel plate ionization chamber. These estimations have been made using numerical integration method when the pulses are processed through the CR-RCn (n=1-6) shaping network as well as when the pulses are processed through the complex shaping network of the ORTEC Model 472 spectroscopic amplifier. Further, we have made simulations to see the effect of ballistic deficit on the pulse-height spectra under different conditions. We have also carried out measurements of the ballistic deficits for the pulses from a two-electrode parallel plate ionization chamber as well as for the pulses from a gridded parallel plate ionization chamber when these pulses are processed through the ORTEC 572 linear amplifier having a simple CR-RC shaping network. The reasonable matching of the simulated ballistic deficits with the experimental ballistic deficits for the CR-RC shaping network clearly establishes the validity of the simulation technique

First Apollo 11 sample return containers arrive at Ellington AFB

NASA Technical Reports Server (NTRS)

1969-01-01

The first Apollo 11 sample return container, containing lunar surface material, arrives at Ellington Air Force Base by air from the Pacific recovery area. Happily posing for photographs with the rock box are (left to right) George M. Low, Manager, Apollo Spacecraft Program, Manned Spacecraft Center (MSC); U.S. Air Force Lt. Gen. Samuel C. Phillips, Apollo Program Director, Office of Manned Space Flight, NASA HQ.; George S. Trimble, MSC Deputy Director (almost obscured); Eugene G. Edmonds, MSC Photographic Technology Laboratory; RIchard S. Johnston (in back), Special Assistant to the MSC Director; Dr. Thomas O. Paine, NASA Administrator; and Dr. Robert R. Gilruth, MSC Director.

Development and validation of a GEANT4 radiation transport code for CT dosimetry

PubMed Central

Carver, DE; Kost, SD; Fernald, MJ; Lewis, KG; Fraser, ND; Pickens, DR; Price, RR; Stabin, MG

2014-01-01

We have created a radiation transport code using the GEANT4 Monte Carlo toolkit to simulate pediatric patients undergoing CT examinations. The focus of this paper is to validate our simulation with real-world physical dosimetry measurements using two independent techniques. Exposure measurements were made with a standard 100-mm CT pencil ionization chamber, and absorbed doses were also measured using optically stimulated luminescent (OSL) dosimeters. Measurements were made in air, a standard 16-cm acrylic head phantom, and a standard 32-cm acrylic body phantom. Physical dose measurements determined from the ionization chamber in air for 100 and 120 kVp beam energies were used to derive photon-fluence calibration factors. Both ion chamber and OSL measurement results provide useful comparisons in the validation of our Monte Carlo simulations. We found that simulated and measured CTDI values were within an overall average of 6% of each other. PMID:25706135

Development and validation of a GEANT4 radiation transport code for CT dosimetry.

PubMed

Carver, D E; Kost, S D; Fernald, M J; Lewis, K G; Fraser, N D; Pickens, D R; Price, R R; Stabin, M G

2015-04-01

The authors have created a radiation transport code using the GEANT4 Monte Carlo toolkit to simulate pediatric patients undergoing CT examinations. The focus of this paper is to validate their simulation with real-world physical dosimetry measurements using two independent techniques. Exposure measurements were made with a standard 100-mm CT pencil ionization chamber, and absorbed doses were also measured using optically stimulated luminescent (OSL) dosimeters. Measurements were made in air with a standard 16-cm acrylic head phantom and with a standard 32-cm acrylic body phantom. Physical dose measurements determined from the ionization chamber in air for 100 and 120 kVp beam energies were used to derive photon-fluence calibration factors. Both ion chamber and OSL measurement results provide useful comparisons in the validation of the Monte Carlo simulations. It was found that simulated and measured CTDI values were within an overall average of 6% of each other.

Simulating synchrotron radiation in accelerators including diffuse and specular reflections

DOE PAGES

Dugan, G.; Sagan, D.

2017-02-24

An accurate calculation of the synchrotron radiation flux within the vacuum chamber of an accelerator is needed for a number of applications. These include simulations of electron cloud effects and the design of radiation masking systems. To properly simulate the synchrotron radiation, it is important to include the scattering of the radiation at the vacuum chamber walls. To this end, a program called synrad3d has been developed which simulates the production and propagation of synchrotron radiation using a collection of photons. Photons generated by a charged particle beam are tracked from birth until they strike the vacuum chamber wall wheremore » the photon is either absorbed or scattered. Both specular and diffuse scattering is simulated. If a photon is scattered, it is further tracked through multiple encounters with the wall until it is finally absorbed. This paper describes the synrad3d program, with a focus on the details of its scattering model, and presents some examples of the program’s use.« less

Characterization and Application of a Disposable Rotating Bed Bioreactor for Mesenchymal Stem Cell Expansion.

PubMed

Neumann, Anne; Lavrentieva, Antonina; Heilkenbrinker, Alexandra; Loenne, Maren; Kasper, Cornelia

2014-11-27

Recruitment of mesenchymal stromal cells (MSC) into the field of tissue engineering is a promising development since these cells can be expanded vivo to clinically relevant numbers and, after expansion, retain their ability to differentiate into various cell lineages. Safety requirements and the necessity to obtain high cell numbers without frequent subcultivation of cells raised the question of the possibility of expanding MSC in one-way (single-use) disposable bioreactors. In this study, umbilical cord-derived MSC (UC-MSC) were expanded in a disposable Z 2000 H bioreactor under dynamic conditions. Z was characterized regarding residence time and mixing in order to evaluate the optimal bioreactor settings, enabling optimal mass transfer in the absence of shear stress, allowing an reproducible expansion of MSC, while maintaining their stemness properties. Culture of the UC-MSC in disposable Z 2000 H bioreactor resulted in a reproducible 8-fold increase of cell numbers after 5 days. Cells were shown to maintain specific MSC surface marker expression as well as trilineage differentiation potential and lack stress-induced premature senescence.

Mechano-Signal Transduction in Mesenchymal Stem Cells Induces Prosaposin Secretion to Drive the Proliferation of Breast Cancer Cells.

PubMed

Ishihara, Seiichiro; Inman, David R; Li, Wan-Ju; Ponik, Suzanne M; Keely, Patricia J

2017-11-15

In response to chemical stimuli from cancer cells, mesenchymal stem cells (MSC) can differentiate into cancer-associated fibroblasts (CAF) and promote tumor progression. How mechanical stimuli such as stiffness of the extracellular matrix (ECM) contribute to MSC phenotype in cancer remains poorly understood. Here, we show that ECM stiffness leads to mechano-signal transduction in MSC, which promotes mammary tumor growth in part through secretion of the signaling protein prosaposin. On a stiff matrix, MSC cultured with conditioned media from mammary cancer cells expressed increased levels of α-smooth muscle actin, a marker of CAF, compared with MSC cultured on a soft matrix. By contrast, MSC cultured on a stiff matrix secreted prosaposin that promoted proliferation and survival of mammary carcinoma cells but inhibited metastasis. Our findings suggest that in addition to chemical stimuli, increased stiffness of the ECM in the tumor microenvironment induces differentiation of MSC to CAF, triggering enhanced proliferation and survival of mammary cancer cells. Cancer Res; 77(22); 6179-89. ©2017 AACR . ©2017 American Association for Cancer Research.

Hencky's model for elastomer forming process

NASA Astrophysics Data System (ADS)

Oleinikov, A. A.; Oleinikov, A. I.

2016-08-01

In the numerical simulation of elastomer forming process, Henckys isotropic hyperelastic material model can guarantee relatively accurate prediction of strain range in terms of large deformations. It is shown, that this material model prolongate Hooke's law from the area of infinitesimal strains to the area of moderate ones. New representation of the fourth-order elasticity tensor for Hencky's hyperelastic isotropic material is obtained, it possesses both minor symmetries, and the major symmetry. Constitutive relations of considered model is implemented into MSC.Marc code. By calculating and fitting curves, the polyurethane elastomer material constants are selected. Simulation of equipment for elastomer sheet forming are considered.

Electromagnetic Compatibility Testing Studies

NASA Technical Reports Server (NTRS)

Trost, Thomas F.; Mitra, Atindra K.

1996-01-01

This report discusses the results on analytical models and measurement and simulation of statistical properties from a study of microwave reverberation (mode-stirred) chambers performed at Texas Tech University. Two analytical models of power transfer vs. frequency in a chamber, one for antenna-to-antenna transfer and the other for antenna to D-dot sensor, were experimentally validated in our chamber. Two examples are presented of the measurement and calculation of chamber Q, one for each of the models. Measurements of EM power density validate a theoretical probability distribution on and away from the chamber walls and also yield a distribution with larger standard deviation at frequencies below the range of validity of the theory. Measurements of EM power density at pairs of points which validate a theoretical spatial correlation function on the chamber walls and also yield a correlation function with larger correlation length, R(sub corr), at frequencies below the range of validity of the theory. A numerical simulation, employing a rectangular cavity with a moving wall shows agreement with the measurements. The determination that the lowest frequency at which the theoretical spatial correlation function is valid in our chamber is considerably higher than the lowest frequency recommended by current guidelines for utilizing reverberation chambers in EMC testing. Two suggestions have been made for future studies related to EMC testing.

The use of decompression to simulate the effect of extravehicular activity on human lymphocyte transformation

NASA Technical Reports Server (NTRS)

Meehan, R. T.; Duncan, U.; Neale, L.; Waligora, J.; Taylor, G. R.

1986-01-01

Lymphocytes from 35 subjects participating in a chamber study simulating extravehicular activity (EVA) conditions were studied. No significant differences in H3 thymidine uptake between pre chamber and post chamber response to any mitogens autologous plasma, or among circulating mononuclear cells by flow cytometry are observed. The studies could not identify the subjects who developed venous bubbles. Data from eight subjects suggests that acute stress associated with participating in the study augments in vitro lymphocyte proliferation. Results indicate EVA exposure does not greatly influence space-flight induced alterations in immune effector cell function.

Nanotechnology for mesenchymal stem cell therapies.

PubMed

Corradetti, Bruna; Ferrari, Mauro

2016-10-28

Mesenchymal stem cells (MSC) display great proliferative, differentiative, chemotactic, and immune-modulatory properties required to promote tissue repair. Several clinical trials based on the use of MSC are currently underway for therapeutic purposes. The aim of this article is to examine the current trends and potential impact of nanotechnology in MSC-driven regenerative medicine. Nanoparticle-based approaches are used as powerful carrier systems for the targeted delivery of bioactive molecules to ensure MSC long-term maintenance in vitro and to enhance their regenerative potential. Nanostructured materials have been developed to recapitulate the stem cell niche within a tissue and to instruct MSC toward the creation of regeneration-permissive environment. Finally, the capability of MSC to migrate toward the site of injury/inflammation has allowed for the development of diagnostic imaging systems able to monitor transplanted stem cell bio-distribution, toxicity, and therapeutic effectiveness. Copyright © 2015 Elsevier B.V. All rights reserved.

Role of aryl hydrocarbon receptor in mesenchymal stromal cell activation: A minireview.

PubMed

de Almeida, Danilo Candido; Evangelista, Laura Sibele Martins; Câmara, Niels Olsen Saraiva

2017-09-26

Mesenchymal stromal cells (MSCs) possess great therapeutic advantages due to their ability to produce a diverse array of trophic/growth factors related to cytoprotection and immunoregulation. MSC activation via specific receptors is a crucial event for these cells to exert their immunosuppressive response. The aryl-hydrocarbon receptor (AhR) is a sensitive molecule for external signals and it is expressed in MSCs and, upon positive activation, may potentially regulate the MSC-associated immunomodulatory function. Consequently, signalling pathways linked to AhR activation can elucidate some of the molecular cascades involved in MSC-mediated immunosuppression. In this minireview, we have noted some important findings concerning MSC regulation via AhR, highlighting that its activation is associated with improvement in migration and immunoregulation, as well as an increase in pro-regenerative potential. Thus, AhR-mediated MSC activation can contribute to new perspectives on MSC-based therapies, particularly those directed at immune-associated disorders.

BMP2 repression and optimized culture conditions promote human bone marrow-derived mesenchymal stem cell isolation.

PubMed

Kay, Alasdair Gawain; Dale, Tina Patricia; Akram, Khondoker Mehedi; Mohan, Param; Hampson, Karen; Maffulli, Nicola; Spiteri, Monica A; El Haj, Alicia Jennifer; Forsyth, Nicholas Robert

2015-01-01

Human mesenchymal stem cells (hMSC) are multipotent progenitor cells. We propose the optimization of hMSC isolation and recovery using the application of a controlled hypoxic environment. We evaluated oxygen, glucose and serum in the recovery of hMSC from bone marrow (BMhMSC). Colony forming units-fibroblastic, cell numbers, tri-lineage differentiation, immunofluorescence and microarray were used to confirm and characterize BMhMSC. In an optimized (2% O(2), 4.5 g/l glucose and 5% serum) environment both colony forming units-fibroblastic (p = 0.01) and cell numbers (p = 0.0001) were enhanced over standard conditions. Transcriptional analysis identified differential expression of bone morphogenetic protein 2 (BMP2) and, putatively, chemokine (C-X-C motif) receptor 2 (CXCR2) signaling pathways. We have detailed a potential milestone in the process of refinement of the BMhMSC isolation process.

Lignin-rich biomass of cotton by-products for biorefineries via pyrolysis.

PubMed

Chen, Jiao; Liang, Jiajin; Wu, Shubin

2016-10-01

Pyrolysis was demonstrated to investigate the thermal decomposition characteristics and potential of lignin-rich cotton by-products cotton exocarp (CE) and spent mushroom substrate consisted of cotton by-products (MSC) for biorefineries. The chemical component and structure alteration of CE and MSC was found to affect their thermochemical behaviors. The bio-oil yield from CE was 58.13wt% while the maximum yield from MSC was 45.01% at 600°C. The phenolic compounds obtained from CE and MSC were 33.9% and 39.2%, respectively. The yield of acetic acid from MSC between 400 and 600°C was about 30-38% lower than that from CE, which suggests the high quality of bio-oil was obtained. Biochar from MSC via slow pyrolysis had a high mass yield (44.38wt%) with well-developed pore structure. Copyright © 2016 Elsevier Ltd. All rights reserved.

Agonism of Wnt/β-catenin signaling promotes mesenchymal stem cell (MSC) expansion

PubMed Central

Hoffman, Michael D.; Benoit, Danielle S.W.

2014-01-01

Promoting mesenchymal stem cell (MSC) proliferation has numerous applications in stem cell therapies, particularly in the area of regenerative medicine. In order for cell-based regenerative approaches to be realized, MSC proliferation must be achieved in a controlled manner without compromising stem cell differentiation capacities. Here we demonstrate that 6-bromoindirubin-3’-oxime (BIO) increases MSC β-catenin activity 106-fold and stem cell-associated gene expression ~33-fold respectively over untreated controls. Subsequently, BIO treatment increases MSC populations 1.8-fold in typical 2D culture conditions, as well as 1.3-fold when encapsulated within hydrogels compared to untreated cells. Furthermore, we demonstrate that BIO treatment does not reduce MSC multipotency, where MSCs maintain their ability to differentiate into osteoblasts, chondrocytes, and adipocytes using standard conditions. Taken together, our results demonstrate BIOs potential utility as a proliferative agent for cell transplantation and tissue regeneration. PMID:23554411

[Mesenchymal stem/stroma cells : Therapeutic potential in the treatment of autoimmune diseases].

PubMed

Schäfer, R; Daikeler, T

2016-10-01

Mesenchymal stem and stromal cells (MSC) are propagated for the treatment of autoimmune and autoinflammatory processes. These cells can be relatively easily obtained from various tissues. The MSC feature anti-inflammatory and immunosuppressive properties in vitro as well as in animal models. Initial reports on the clinical application of MSC for various diseases are available, some with promising results and so far no reported toxicity; however, data from phase III studies are still lacking and crucial questions are still unanswered. The MSC preparations used are heterogeneous and also differ depending on the source and it is unclear whether autologous (own) or allogeneic (foreign) MSC are more suitable for therapeutic use. Long-term consequences, such as possible malignant transformation and possible endogenous tumor growth stimulation cannot be completely excluded. Ultimately, these questions can only be answered through randomized controlled trials for defined clinical indications with defined MSC.

Visualisation of the mechanosensitive channel of large conductance in bacteria using confocal microscopy.

PubMed

Norman, Christel; Liu, Zhen-Wei; Rigby, Paul; Raso, Albert; Petrov, Yevgeniy; Martinac, Boris

2005-07-01

The mechanosensitive channel of large conductance (MscL) plays an important role in the survival of bacterial cells to hypo-osmotic shock. This channel has been extensively studied and its sequence, structure and electrophysiological characteristics are well known. Here we present a method to visualise MscL in living bacteria using confocal microscopy. By creating a gene fusion between mscl and the gene encoding the green fluorescent protein (GFP) we were able to express the fusion protein MscL-GFP in bacteria. We show that MscL-GFP is present in the cytoplasmic membrane and forms functional channels. These channels have the same characteristics as wild-type MscL, except that they require more pressure to open. This method could prove an interesting, non-invasive, tool to study the localisation and the regulation of expression of MscL in bacteria.

Design of a hydraulic analog of the circulatory system for evaluating artificial hearts.

PubMed

Donovan, F M

1975-01-01

A major problem in improving artificial heart designs is the absence of methods for accurate in vitro testing of artificial heart systems. A mock circulatory system has been constructed which hydraulically simulates the systemic and pulmonary circulations of the normal human. The device is constructed of 1/2 in. acrylic sheet and has overall dimensions of 24 in. wide, 16 in. tall, and 8 in. deep. The artificial heart to be tested is attached to the front of the device, and pumps fluid from the systemic venous chamber into the pulmonary arterial chamber and from the pulmonary venous chamber into the systemic arterial chamber. Each of the four chambers is hermetically sealed. The compliance of each chamber is determined by the volume of air trapped above the fluid in that chamber. The pulmonary and systemic resistances are set automatically by bellows-operated valves to simulate the barroreceptor response in the systemic arteries and the passive pulmonary resistance response in the pulmonary arteries. Cardiac output is measured by a turbine flowmeter in the systemic circulation. Results using the Kwan-Gett artificial heart show a good comparison between the mock circulatory system response and the calf response.

Astronaut Russell Schweickart inside simulator for EVA training

NASA Image and Video Library

1968-12-11

S68-55391 (11 Dec. 1968) --- Astronaut Russell L. Schweickart, lunar module pilot of the Apollo 9 (Spacecraft 104/Lunar Module 3/Saturn 504) space mission, is seen inside Chamber "A," Space Environment Simulation Laboratory, Building 32, participating in dry run activity in preparation for extravehicular activity which is scheduled in Chamber "A." The purpose of the scheduled training is to familiarize the crewmen with the operation of EVA equipment in a simulated space environment. In addition, metabolic and workload profiles will be simulated on each crewman. Astronauts Schweickart and Alan L. Bean, backup lunar module pilot, are scheduled to receive thermal-vacuum training simulating Earth-orbital EVA.

The mechanoelectrical response of the cytoplasmic membrane of Vibrio cholerae.

PubMed

Rowe, Ian; Elahi, Merina; Huq, Anwar; Sukharev, Sergei

2013-07-01

Persistence of Vibrio cholerae in waters of fluctuating salinity relies on the capacity of this facultative enteric pathogen to adapt to varying osmotic conditions. In an event of osmotic downshift, osmolytes accumulated inside the bacterium can be quickly released through tension-activated channels. With the newly established procedure of giant spheroplast preparation from V. cholerae, we performed the first patch-clamp characterization of its cytoplasmic membrane and compared tension-activated currents with those in Esherichia coli. Saturating pressure ramps revealed two waves of activation belonging to the ∼1-nS mechanosensitive channel of small conductance (MscS)-like channels and ∼3-nS mechanosensitive channel of large conductance (MscL)-like channels, with a pressure midpoint ratio p0.5MscS/p0.5MscL of 0.48. We found that MscL-like channels in V. cholerae present at a density three times higher than in E. coli, and yet, these vibrios were less tolerant to large osmotic downshocks. The Vibrio MscS-like channels exhibit characteristic inward rectification and subconductive states at depolarizing voltages; they also adapt and inactivate at subsaturating tensions and recover within 2 s upon tension release, just like E. coli MscS. Trehalose, a compatible internal osmolyte accumulated under hypertonic conditions, significantly shifts activation curves of both MscL- and MscS-like channels toward higher tensions, yet does not freely partition into the channel pore. Direct electrophysiology of V. cholerae offers new avenues for the in situ analysis of membrane components critical for osmotic survival and electrogenic transport in this pathogen.

The mechanoelectrical response of the cytoplasmic membrane of Vibrio cholerae

PubMed Central

Rowe, Ian; Elahi, Merina; Huq, Anwar

2013-01-01

Persistence of Vibrio cholerae in waters of fluctuating salinity relies on the capacity of this facultative enteric pathogen to adapt to varying osmotic conditions. In an event of osmotic downshift, osmolytes accumulated inside the bacterium can be quickly released through tension-activated channels. With the newly established procedure of giant spheroplast preparation from V. cholerae, we performed the first patch-clamp characterization of its cytoplasmic membrane and compared tension-activated currents with those in Esherichia coli. Saturating pressure ramps revealed two waves of activation belonging to the ∼1-nS mechanosensitive channel of small conductance (MscS)-like channels and ∼3-nS mechanosensitive channel of large conductance (MscL)-like channels, with a pressure midpoint ratio p0.5MscS/p0.5MscL of 0.48. We found that MscL-like channels in V. cholerae present at a density three times higher than in E. coli, and yet, these vibrios were less tolerant to large osmotic downshocks. The Vibrio MscS-like channels exhibit characteristic inward rectification and subconductive states at depolarizing voltages; they also adapt and inactivate at subsaturating tensions and recover within 2 s upon tension release, just like E. coli MscS. Trehalose, a compatible internal osmolyte accumulated under hypertonic conditions, significantly shifts activation curves of both MscL- and MscS-like channels toward higher tensions, yet does not freely partition into the channel pore. Direct electrophysiology of V. cholerae offers new avenues for the in situ analysis of membrane components critical for osmotic survival and electrogenic transport in this pathogen. PMID:23797422

Viscoelastic and histologic properties in scarred rabbit vocal folds after mesenchymal stem cell injection.

PubMed

Hertegård, S; Cedervall, J; Svensson, B; Forsberg, K; Maurer, F H J; Vidovska, D; Olivius, P; Ahrlund-Richter, L; Le Blanc, K

2006-07-01

The aim of this study was to analyze the short-term viscoelastic and histologic properties of scarred rabbit vocal folds after injection of human mesenchymal stem cells (MSC) as well as the degree of MSC survival. Because MSCs are antiinflammatory and regenerate mesenchymal tissues, can MSC injection reduce vocal fold scarring after injury? Twelve vocal folds from 10 New Zealand rabbits were scarred by a localized resection and injected with human MSC or saline. Eight vocal folds were left as controls. After 4 weeks, 10 larynges were stained for histology and evaluation of the lamina propria thickness. Collagen type I content was analyzed from six rabbits. MSC survival was analyzed by fluorescent in situ hybridization staining from three rabbits. Viscoelasticity for 10 vocal folds was analyzed in a parallel-plate rheometer. The rheometry on fresh-frozen samples showed decreased dynamic viscosity and lower elastic modulus (P<.01) in the scarred samples injected with MSC as compared with the untreated scarred group. Normal controls had lower dynamic viscosity and elastic modulus as compared with the scarred untreated and treated vocal folds (P<.01). Histologic analysis showed a higher content of collagen type 1 in the scarred samples as compared with the normal vocal folds and with the scarred folds treated with MSC. MSCs remained in all samples analyzed. The treated scarred vocal folds showed persistent MSC. Injection of scarred rabbit vocal folds with MSC rendered improved viscoelastic parameters and less signs of scarring expressed as collagen content in comparison to the untreated scarred vocal folds.

Therapeutic Potential of Mesenchymal Stem Cell-Derived Exosomes in the Treatment of Eye Diseases.

PubMed

Harrell, C Randall; Simovic Markovic, Bojana; Fellabaum, Crissy; Arsenijevic, Aleksandar; Djonov, Valentin; Arsenijevic, Nebojsa; Volarevic, Vladislav

2018-05-18

Mesenchymal stem cells (MSCs) were, due to their immunomodulatory and pro-angiogenic characteristics, extensively explored as new therapeutic agents in cell-based therapy of uveitis, glaucoma, retinal and ocular surface diseases.Since it was recently revealed that exosomes play an important role in biological functions of MSCs, herewith we summarized current knowledge about the morphology, structure, phenotype and functional characteristics of MSC-derived exosomes emphasizing their therapeutic potential in the treatment of eye diseases.MSC-derived exosomes were as efficient as transplanted MSCs in limiting the extent of eye injury and inflammation. Immediately after intravitreal injection, MSC-derived exosomes, due to nano-dimension, diffused rapidly throughout the retina and significantly attenuated retinal damage and inflammation. MSC-derived exosomes successfully delivered trophic and immunomodulatory factors to the inner retina and efficiently promoted survival and neuritogenesis of injured retinal ganglion cells. MSC-derived exosomes efficiently suppressed migration of inflammatory cells, attenuated detrimental Th1 and Th17 cell-driven immune response and ameliorated experimental autoimmune uveitis. MSC-derived exosomes were able to fuse with the lysosomes within corneal cells, enabling delivering of MSC-derived active β-glucuronidase and consequent catabolism of accumulated glycosaminoglycans, indicating their therapeutic potential in the treatment of Mucopolysaccharidosis VII (Sly Syndrome). Importantly, beneficent effects were noticed only in animals that received MSC-derived exosomes and were not seen after therapy with fibroblasts-derived exosomes confirming specific therapeutic potential of MSCs and their products in the treatment of eye diseases.In conclusion, MSC-derived exosomes represent potentially new therapeutic agents in the therapy of degenerative and inflammatory ocular diseases.

BLDG. 29 - INTERIOR (CLOSEUP) - GONDOLA - MSC

NASA Image and Video Library

1966-01-01

The new centrifuge at MSC, located in the Flight Acceleration Facility (FAF), Bldg. 29. The 50-ft. arm can swing the 3-man gondola to create G-Forces Astronauts will experience during liftoffs and re-entry conditions. MSC, HOUSTON, TX CN

Intra-EVA Space-to-Ground Interactions when Conducting Scientific Fieldwork Under Simulated Mars Mission Constraints

NASA Technical Reports Server (NTRS)

Beaton, Kara H.; Chappell, Steven P.; Abercromby, Andrew F. J.; Lim, Darlene S. S.

2018-01-01

The Biologic Analog Science Associated with Lava Terrains (BASALT) project is a four-year program dedicated to iteratively designing, implementing, and evaluating concepts of operations (ConOps) and supporting capabilities to enable and enhance scientific exploration for future human Mars missions. The BASALT project has incorporated three field deployments during which real (non-simulated) biological and geochemical field science have been conducted at two high-fidelity Mars analog locations under simulated Mars mission conditions, including communication delays and data transmission limitations. BASALT's primary Science objective has been to extract basaltic samples for the purpose of investigating how microbial communities and habitability correlate with the physical and geochemical characteristics of chemically altered basalt environments. Field sites include the active East Rift Zone on the Big Island of Hawai'i, reminiscent of early Mars when basaltic volcanism and interaction with water were widespread, and the dormant eastern Snake River Plain in Idaho, similar to present-day Mars where basaltic volcanism is rare and most evidence for volcano-driven hydrothermal activity is relict. BASALT's primary Science Operations objective has been to investigate exploration ConOps and capabilities that facilitate scientific return during human-robotic exploration under Mars mission constraints. Each field deployment has consisted of ten extravehicular activities (EVAs) on the volcanic flows in which crews of two extravehicular and two intravehicular crewmembers conducted the field science while communicating across time delay and under bandwidth constraints with an Earth-based Mission Support Center (MSC) comprised of expert scientists and operators. Communication latencies of 5 and 15 min one-way light time and low (0.512 Mb/s uplink, 1.54 Mb/s downlink) and high (5.0 Mb/s uplink, 10.0 Mb/s downlink) bandwidth conditions were evaluated. EVA crewmembers communicated with the MSC via voice and text messaging. They also provided scientific instrument data, still imagery, video streams from chest-mounted cameras, GPS location tracking information. The MSC monitored and reviewed incoming data from the field across delay and provided recommendations for pre-sampling and sampling tasks based on their collective expertise. The scientists used dynamic priority ranking lists, referred to as dynamic leaderboards, to track and rank candidate samples relative to one another and against the science objectives for the current EVA and the overall mission. Updates to the dynamic leaderboards throughout the EVA were relayed regularly to the IV crewmembers. The use of these leaderboards enabled the crew to track the dynamic nature of the MSC recommendations and helped minimize crew idle time (defined as time spent waiting for input from Earth during which no other productive tasks are being performed). EVA timelines were strategically designed to enable continuous (delayed) feedback from an Earth-based Science Team while simultaneously minimizing crew idle time. Such timelines are operationally advantageous, reducing transport costs by eliminating the need for crews to return to the same locations on multiple EVAs while still providing opportunities for recommendations from science experts on Earth, and scientifically advantageous by minimizing the potential for cross-contamination across sites. This paper will highlight the space-to-ground interaction results from the three BASALT field deployments, including planned versus actual EVA timeline data, ground assimilation times (defined as the amount of time available to the MSC to provide input to the crew), and idle time. Furthermore, we describe how these results vary under the different communication latency and bandwidth conditions. Together, these data will provide a basis for guiding and prioritizing capability development for future human exploration missions.

Wenckebach upper rate response in single chamber pacemaker.

PubMed

Barold, S S

2000-07-01

The Medtronic Minix pacemaker during normal function in the VVT mode was found to exhibit a Wenckenbach upper rate response similar to that of dual chamber devices. This behavior occurred only when the upper rate interval was longer than the pacemaker refractory period. In a single chamber device this response may simulate pacemaker malfunction.

The response of a scintillation counter below an emulsion chamber to heavy nucleus interactions in the chamber

NASA Technical Reports Server (NTRS)

Burnett, T. H.; Dake, S.; Derrickson, J. H.; Fountain, W. F.; Fuki, M.; Gregory, J. C.; Hayashi, T.; Hayashi, T.; Holynski, R.; Iwai, J.;

The effect of mesenchymal stem cell sheets on structural allograft healing of critical-sized femoral defects in mice

PubMed Central

Long, Teng; Zhu, Zhenan; Awad, Hani A.; Schwarz, Edward M.; Hilton, Matthew J.; Dong, Yufeng

2014-01-01

Structural bone allografts are widely used in the clinic to treat critical sized bone defects, despite lacking the osteoinductive characteristics of live autografts. To address this, we generated revitalized structural allografts wrapped with mesenchymal stem/progenitor cell (MSC) sheets, which were produced by expanding primary syngenic bone marrow derived cells on temperature-responsive plates, as a tissue engineered periosteum. In vitro assays demonstrated maintenance of the MSC phenotype in the sheets, suggesting that short-term culturing of MSC sheets is not detrimental. To test their efficacy in vivo, allografts wrapped with MSC sheets were transplanted into 4-mm murine femoral defects and compared to allografts with direct seeding of MSCs and allografts without cells. Evaluations consisted of x-ray plain radiography, 3D microCT, histology, and biomechanical testing at 4- and 6-weeks post-surgery. Our findings demonstrate that MSC sheets induce prolonged cartilage formation at the graft-host junction and enhanced bone callus formation, as well as graft-host osteointegration. Moreover, a large periosteal callus was observed spanning the allografts with MSC sheets, which partially mimics live autograft healing. Finally, biomechanical testing showed a significant increase in the structural and functional properties of MSC sheet grafted femurs. Taken together, MSC sheets exhibit enhanced osteogenicity during critical sized bone defect repair, demonstrating the feasibility of this tissue engineering solution for massive allograft healing. PMID:24393269

Interannual variability in stratiform cloudiness and sea surface temperature

NASA Technical Reports Server (NTRS)

Norris, Joel R.; Leovy, Conway B.

1994-01-01

Marine stratiform cloudiness (MSC)(stratus, stratocumulus, and fog) is widespread over subtropical oceans west of the continents and over midlatitude oceans during summer, the season when MSC has maximum influence on surface downward radiation and is most influenced by boundary-layer processes. Long-term datasets of cloudiness and sea surface teperature (SST) from surface observations from 1952 to 1981 are used to examine interannual variations in MSC and SST. Linear correlations of anomalies in seasonal MSC amount with seasonal SST anomalies are negative and significant in midlatitude and eastern subtropical oceans, especially during summer. Significant negative correlations between SST and nimbostratus and nonprecipitating midlevel cloudiness are also observed at midlatitudes during summer, suggesting that summer storm tracks shift from year to year following year-to-year meridional shifts in the SST gradient. Over the 30-yr period, there are significant upward trends in MSC amount over the northern midlatitude oceans and a significant downward trend off the coast of California. The highest correlations and trends occur where gradients in MSC and SST are strongest. During summer, correlations between SST and MSC anomalies peak at zero lag in midlatitudes where warm advection prevails, but SST lags MSC in subtropical regions where cold advection predominates. This difference is attributed to a tendency for anomalies in latent heat flux to compensate anomalies in surface downward radiation in warm advection regions but not in cold advection regions.

Effective treatment of steroid and therapy-refractory acute graft-versus-host disease with a novel mesenchymal stromal cell product (MSC-FFM).

PubMed

Bader, Peter; Kuçi, Zyrafete; Bakhtiar, Shahrzad; Basu, Oliver; Bug, Gesine; Dennis, Michael; Greil, Johann; Barta, Aniko; Kállay, Krisztián M; Lang, Peter; Lucchini, Giovanna; Pol, Raj; Schulz, Ansgar; Sykora, Karl-Walter; von Luettichau, Irene; Herter-Sprie, Grit; Uddin, Mohammad Ashab; Jenkin, Phil; Alsultan, Abdulrahman; Buechner, Jochen; Stein, Jerry; Kelemen, Agnes; Jarisch, Andrea; Soerensen, Jan; Salzmann-Manrique, Emilia; Hutter, Martin; Schäfer, Richard; Seifried, Erhard; Klingebiel, Thomas; Bonig, Halvard; Kuçi, Selim

2018-01-29

The inability to generate mesenchymal stromal cells (MSCs) of consistent potency likely is responsible for inconsistent clinical outcomes of patients with aGvHD receiving MSC products. We developed a novel MSC manufacturing protocol characterized by high in vitro potency and near-identity of individual doses, referred to as "MSC-Frankfurt am Main (MSC-FFM)". Herein, we report outcomes of the 69 patients who have received MSC-FFM. These were 51 children and 18 adults with refractory aGvHD grade II (4%), III (36%) or IV (59%). Patients were refractory either to frontline therapy (steroids) (29%) or to steroids and 1-5 additional lines of immunosuppressants (71%) were given infusions in four weekly intervals. The day 28 overall response rate was 83%; at the last follow-up, 61% and 25% of patients were in complete or partial remission. The median follow-up was 8.1 months. Six-month estimate for cumulative incidence of non-relapse mortality was 27% (range, 16-38); leukemia relapse mortality was 2% (range, 0-5). This was associated with a superior six-month overall survival (OS) probability rate of 71% (range, 61-83), compared to the outcome of patients not treated with MSC-FFM. This novel product was effective in children and adults, suggesting that MSC-FFM represents a promising therapy for steroid refractory aGvHD.

Mesenchymal stem cell sheets exert anti-stenotic effects in a rat arterial injury model.

PubMed

Homma, Jun; Sekine, Hidekazu; Matsuura, Katsuhisa; Kobayashi, Eiji; Shimizu, Tatsuya

2018-05-04

Restenosis after catheter or surgical intervention substantially affects the prognosis of arterial occlusive disease. Mesenchymal stem cells (MSCs) may have anti-stenotic effects on injured arteries. MSC transplantation from the adventitial side of an artery is safer than endovascular transplantation but has not been extensively examined. In this study, a rat model of femoral artery injury was used to compare the anti-stenotic effects of transplanted cell sheets and transplanted cell suspensions. Rat adipose-derived stem cells (ASCs) were used as the source of MSCs. For both cell sheets and suspensions, 6×106 MSCs were transplanted on the day of arterial injury. MSC sheets attenuated neointimal hyperplasia more than MSC suspensions (intima-to-media ratio in haematoxylin/eosin-stained sections: 0.55±0.13 vs. 1.14±0.12; P<0.05). Cell engraftment (assessed by immunohistochemistry or bioluminescence imaging of luciferase-expressing cells), arterial re-endothelialisation (evaluated by immunohistochemical staining for rat endothelial cell antigen-1) and restriction of vascular smooth muscle cell proliferation in the neointima (double-staining of alpha-smooth muscle actin and phospho-histone H3) were greater when MSC sheets were applied than when MSC suspensions were used. In conclusion, MSC sheets exhibited better anti-stenotic and cell engraftment properties than MSC suspensions. MSC sheet transplantation from the adventitial side is a promising therapy for prevention of arterial restenosis.

Characterization of bone marrow mesenchymal stromal cells in aplastic anaemia.

PubMed

Hamzic, Edita; Whiting, Karen; Gordon Smith, Edward; Pettengell, Ruth

2015-06-01

In aplastic anaemia (AA), haemopoietic activity is significantly reduced and generally attributed to failure of haemopoietic stem cells (HSC) within the bone marrow (BM). The regulation of haemopoiesis depends on the interaction between HSC and various cells of the BM microenvironment, including mesenchymal stromal cells (MSC). MSC involvement in the functional restriction of HSC in AA is largely unknown and therefore, the physical and functional properties of AA MSC were studied in vitro. MSC were characterized by their phenotype and ability to form adherent stromal layers. The functional properties of AA MSC were assessed through proliferative, clonogenic and cross-over culture assays. Results indicate that although AA MSC presented typical morphology and distinctive mesenchymal markers, stromal formation was reduced, with 50% of BM samples failing to produce adherent layers. Furthermore, their proliferative and clonogenic capacity was markedly decreased (P = 0·03 and P = 0·04 respectively) and the ability to sustain haemopoiesis was significantly reduced, as assessed by total cell proliferation (P = 0·032 and P = 0·019 at Week 5 and 6, respectively) and clonogenic potential of HSC (P = 0·02 at Week 6). It was concluded that the biological characteristics of AA MSC are different from those of control MSC and their in vitro haemopoiesis-supporting ability is significantly reduced. © 2015 John Wiley & Sons Ltd.

Priming Adipose-Derived Mesenchymal Stem Cells with Hyaluronan Alters Growth Kinetics and Increases Attachment to Articular Cartilage

PubMed Central

Succar, Peter; Medynskyj, Michael; Breen, Edmond J.; Batterham, Tony; Molloy, Mark P.; Herbert, Benjamin R.

2016-01-01

Background. Biological therapeutics such as adipose-derived mesenchymal stem cell (MSC) therapy are gaining acceptance for knee-osteoarthritis (OA) treatment. Reports of OA-patients show reductions in cartilage defects and regeneration of hyaline-like-cartilage with MSC-therapy. Suspending MSCs in hyaluronan commonly occurs in animals and humans, usually without supporting data. Objective. To elucidate the effects of different concentrations of hyaluronan on MSC growth kinetics. Methods. Using a range of hyaluronan concentrations, we measured MSC adherence and proliferation on culture plastic surfaces and a novel cartilage-adhesion assay. We employed time-course and dispersion imaging to assess MSC binding to cartilage. Cytokine profiling was also conducted on the MSC-secretome. Results. Hyaluronan had dose-dependent effects on growth kinetics of MSCs at concentrations of entanglement point (1 mg/mL). At higher concentrations, viscosity effects outweighed benefits of additional hyaluronan. The cartilage-adhesion assay highlighted for the first time that hyaluronan-primed MSCs increased cell attachment to cartilage whilst the presence of hyaluronan did not. Our time-course suggested patients undergoing MSC-therapy for OA could benefit from joint-immobilisation for up to 8 hours. Hyaluronan also greatly affected dispersion of MSCs on cartilage. Conclusion. Our results should be considered in future trials with MSC-therapy using hyaluronan as a vehicle, for the treatment of OA. PMID:26981136

Mesenchymal stromal cell derived extracellular vesicles rescue radiation damage to murine marrow hematopoietic cells

PubMed Central

Wen, Sicheng; Dooner, Mark; Cheng, Yan; Papa, Elaine; Del Tatto, Michael; Pereira, Mandy; Deng, Yanhui; Goldberg, Laura; Aliotta, Jason; Chatterjee, Devasis; Stewart, Connor; Carpanetto, Andrea; Collino, Federica; Bruno, Stefania; Camussi, Giovanni; Quesenberry, Peter

2016-01-01

Mesenchymal stromal cells (MSC) have been shown to reverse radiation damage to marrow stem cells. We have evaluated the capacity of MSC-derived extracellular vesicles (MSC-EVs) to mitigate radiation injury to marrow stem cells at 4 hours to 7 days after irradiation. Significant restoration of marrow stem cell engraftment at 4, 24 and 168 hours post-irradiation by exposure to MSC-EVs was observed at 3 weeks to 9 months after transplant and further confirmed by secondary engraftment. Intravenous injection of MSC-EVs to 500cGy exposed mice led to partial recovery of peripheral blood counts and restoration of the engraftment of marrow. The murine hematopoietic cell line, FDC-P1 exposed to 500 cGy, showed reversal of growth inhibition, DNA damage and apoptosis on exposure to murine or human MSC-EVs. Both murine and human MSC-EVs reverse radiation damage to murine marrow cells and stimulate normal murine marrow stem cell/progenitors to proliferate. A preparation with both exosomes and microvesicles was found to be superior to either microvesicles or exosomes alone. Biologic activity was seen in freshly isolated vesicles and in vesicles stored for up to 6 months in 10% DMSO at −80°C. These studies indicate that MSC-EVs can reverse radiation damage to bone marrow stem cells. PMID:27150009

Growth Factor-Reinforced ECM Fabricated from Chemically Hypoxic MSC Sheet with Improved In Vivo Wound Repair Activity.

PubMed

Du, Hui-Cong; Jiang, Lin; Geng, Wen-Xin; Li, Jing; Zhang, Rui; Dang, Jin-Ge; Shu, Mao-Guo; Li, Li-Wen

2017-01-01

MSC treatment can promote cutaneous wound repair through multiple mechanisms, and paracrine mediators secreted by MSC are responsible for most of its therapeutic benefits. Recently, MSC sheet composed of live MSCs and their secreted ECMs was reported to promote wound healing; however, whether its ECM alone could accelerate wound closure remained unknown. In this study, Nc-ECM and Cc-ECM were prepared from nonconditioned and CoCl 2 -conditioned MSC sheets, respectively, and their wound healing properties were evaluated in a mouse model of full-thickness skin defect. Our results showed that Nc-ECM can significantly promote wound repair through early adipocyte recruitment, rapid reepithelialization, enhanced granulation tissue growth, and augmented angiogenesis. Moreover, conditioning of MSC sheet with CoCl 2 dramatically enriched its ECM with collagen I, collagen III, TGF- β 1, VEGF, and bFGF via activation of HIF-1 α and hence remarkably improved its ECM's in vivo wound healing potency. All the Cc-ECM-treated wounds completely healed on day 7, while Nc-ECM-treated wounds healed about 85.0% ± 8.6%, and no-treatment wounds only healed 69.8% ± 9.6% ( p < 0.05). Therefore, we believe that such growth factor-reinforced ECM fabricated from chemically hypoxic MSC sheet has the potential for clinical translation and will lead to a MSC-derived, cost-effective, bankable biomaterial for wound management.

Investigation of particle and vapor wall-loss effects on controlled wood-smoke smog-chamber experiments

NASA Astrophysics Data System (ADS)

Bian, Q.; May, A. A.; Kreidenweis, S. M.; Pierce, J. R.

2015-10-01

Smog chambers are extensively used to study processes that drive gas and particle evolution in the atmosphere. A limitation of these experiments is that particles and gas-phase species may be lost to chamber walls on shorter timescales than the timescales of the atmospheric processes being studied in the chamber experiments. These particle and vapor wall losses have been investigated in recent studies of secondary organic aerosol (SOA) formation, but they have not been systematically investigated in experiments of primary emissions from combustion. The semi-volatile nature of combustion emissions (e.g. from wood smoke) may complicate the behavior of particle and vapor wall deposition in the chamber over the course of the experiments due to the competition between gas/particle and gas/wall partitioning. Losses of vapors to the walls may impact particle evaporation in these experiments, and potential precursors for SOA formation from combustion may be lost to the walls, causing underestimations of aerosol yields. Here, we conduct simulations to determine how particle and gas-phase wall losses contributed to the observed evolution of the aerosol during experiments in the third Fire Lab At Missoula Experiment (FLAME III). We use the TwO-Moment Aerosol Sectional (TOMAS) microphysics algorithm coupled with the organic volatility basis set (VBS) and wall-loss formulations to examine the predicted extent of particle and vapor wall losses. We limit the scope of our study to the dark periods in the chamber before photo-oxidation to simplify the aerosol system for this initial study. Our model simulations suggest that over one-third of the initial particle-phase organic mass (41 %) was lost during the experiments, and over half of this particle-organic mass loss was from direct particle wall loss (65 % of the loss) with the remainder from evaporation of the particles driven by vapor losses to the walls (35 % of the loss). We perform a series of sensitivity tests to understand uncertainties in our simulations. Uncertainty in the initial wood-smoke volatility distribution contributes 18 % uncertainty to the final particle-organic mass remaining in the chamber (relative to base-assumption simulation). We show that the total mass loss may depend on the effective saturation concentration of vapor with respect to the walls as these values currently vary widely in the literature. The details of smoke dilution during the filling of smog chambers may influence the mass loss to the walls, and a dilution of ~ 25:1 during the experiments increased particle-organic mass loss by 33 % compared to a simulation where we assume the particles and vapors are initially in equilibrium in the chamber. Finally, we discuss how our findings may influence interpretations of emission factors and SOA production in wood-smoke smog-chamber experiments.

Investigation of particle and vapor wall-loss effects on controlled wood-smoke smog-chamber experiments

NASA Astrophysics Data System (ADS)

Bian, Q.; May, A. A.; Kreidenweis, S. M.; Pierce, J. R.

2015-06-01

Smog chambers are extensively used to study processes that drive gas and particle evolution in the atmosphere. A limitation of these experiments is that particles and gas-phase species may be lost to chamber walls on shorter timescales than the timescales of the atmospheric processes being studied in the chamber experiments. These particle and vapor wall losses have been investigated in recent studies of secondary organic aerosol (SOA) formation, but they have not been systematically investigated in experiments of primary emissions from combustion. The semi-volatile nature of combustion emissions (e.g. from wood smoke) may complicate the behavior of particle and vapor wall deposition in the chamber over the course of the experiments due to the competition between gas/particle and gas/wall partitioning. Losses of vapors to the walls may impact particle evaporation in these experiments, and potential precursors for SOA formation from combustion may be lost to the walls, causing underestimates of aerosol yields. Here, we conduct simulations to determine how particle and gas-phase wall losses contributed to the observed evolution of the aerosol during experiments in the third Fire Lab At Missoula Experiment (FLAME III). We use the TwO-Moment Aerosol Sectional (TOMAS) microphysics algorithm coupled with the organic volatility basis set (VBS) and wall-loss formulations to examine the predicted extent of particle and vapor wall losses. We limit the scope of our study to the dark periods in the chamber before photo-oxidation to simplify the aerosol system for this initial study. Our model simulations suggest that over one third of the initial particle-phase organic mass (36%) was lost during the experiments, and roughly half of this particle organic mass loss was from direct particle wall loss (56% of the loss) with the remainder from evaporation of the particles driven by vapor losses to the walls (44% of the loss). We perform a series of sensitivity tests to understand uncertainties in our simulations. Uncertainty in the initial wood-smoke volatility distribution contributes 23% uncertainty to the final particle organic mass remaining in the chamber (relative to base-assumptions simulation). We show that the total mass loss may depend on the effective saturation concentration of vapor with respect to the walls as these values currently vary widely in the literature. The details of smoke dilution during the filling of smog chambers may influence the mass loss to the walls, and a dilution of ~ 25:1 during the experiments increased particle organic mass loss by 64% compared to a simulation where we assume the particles and vapors are initially in equilibrium in the chamber. Finally, we discuss how our findings may influence interpretations of emission factors and SOA production in wood-smoke smog-chamber experiments.

Biomimetic Multispiked Connecting Ti-Alloy Scaffold Prototype for Entirely-Cementless Resurfacing Arthroplasty Endoprostheses-Exemplary Results of Implantation of the Ca-P Surface-Modified Scaffold Prototypes in Animal Model and Osteoblast Culture Evaluation.

PubMed

Uklejewski, Ryszard; Rogala, Piotr; Winiecki, Mariusz; Tokłowicz, Renata; Ruszkowski, Piotr; Wołuń-Cholewa, Maria

2016-06-29

We present here-designed, manufactured, and tested by our research team-the Ti-alloy prototype of the multispiked connecting scaffold (MSC-Scaffold) interfacing the components of resurfacing arthroplasty (RA) endoprostheses with bone. The spikes of the MSC-Scaffold prototype mimic the interdigitations of the articular subchondral bone, which is the natural biostructure interfacing the articular cartilage with the periarticular trabecular bone. To enhance the osteoinduction/osteointegration potential of the MSC-Scaffold, the attempts to modify its bone contacting surfaces by the process of electrochemical cathodic deposition of Ca-P was performed with further immersion of the MSC-Scaffold prototypes in SBF in order to transform the amorphous calcium-phosphate coating in hydroxyapatite-like (HA-like) coating. The pilot experimental study of biointegration of unmodified and Ca-P surface-modified MSC-Scaffold prototypes was conducted in an animal model (swine) and in osteoblast cell culture. On the basis of a microscope-histological method the biointegration was proven by the presence of trabeculae in the interspike spaces of the MSC-Scaffold prototype on longitudinal and cross-sections of bone-implant specimens. The percentage of trabeculae in the area between the spikes of specimen containing Ca-P surface modified scaffold prototype observed in microCT reconstructions of the explanted joints was visibly higher than in the case of unmodified MSC-Scaffold prototypes. Significantly higher Alkaline Phosphatase (ALP) activity and the cellular proliferation in the case of Ca-P-modified MSC-Scaffold pre-prototypes, in comparison with unmodified pre-prototypes, was found in osteoblast cell cultures. The obtained results of experimental implantation in an animal model and osteoblast cell culture evaluations of Ca-P surface-modified and non-modified biomimetic MSC-Scaffold prototypes for biomimetic entirely-cementless RA endoprostheses indicate the enhancement of the osteoinduction/osteointegration potential by the Ca-P surface modification of the Ti-alloy MSC-Scaffold prototype. Planned further research on the prototype of this biomimetic MSC-Scaffold for a new generation of RA endoprostheses is also given.

Interdisciplinary MSc and Doctoral Education in Climate System Science at the University of Hamburg

NASA Astrophysics Data System (ADS)

Dilly, Oliver; Stammer, Detlef; Pfeiffer, Eva-Maria

2010-05-01

Modern education in climate system sciences is based on a number of disciplines such as meteorology, geophysics, oceanography, geosciences and also economics and social sciences. Facts across these disciplines are required to address the faced key issues related to climate change effectively. Climate experts need to have profound knowledge that can only be achieved in interdisciplinary MSc and PhD programs. In Europe, graduate students who completed a BSc degree are typically proceeding with MSc programs to increase knowledge and qualification. Afterwards, the participation in a doctoral program may follow. Many doctoral programs include courses supporting disciplinary methodological and scientific background in particular. Those courses derive either from advanced MSc programs or specific trainings. Typically, interdisciplinary exchange is difficult to achieve at any stage of disciplinary graduate programs. Recent developments showed the need to educate climate experts in interdisciplinary MSc programs in climate system sciences for both researchers and professionals outside the university. The University of Hamburg offers an interdisciplinary 2-yr MSc program in Integrated System Sciences with 120 ECTS (30 compulsory, 90 eligible) in English language. If the MSc student decides to proceed with a PhD thesis, he/she may not necessarily complete the MSc program but may start to work on a specific and disciplinary doctoral thesis for 3 years. Each doctoral student is guided by an advisory panel (AP) which meets at least bi-annually. The AP consists of a Principal Advisor, a Co-Advisor and a Chair of the panel who come from neighboring disciplines. The structured doctoral program with only 12 CPs includes interdisciplinary compulsory courses and tailor-made eligible expert courses. Summer schools and soft skill courses add to both MSc and doctoral programs. Accordingly, the new graduate school concepts in climate system sciences at the University of Hamburg supports starting with the interdisciplinary MSc program Integrated Climate System Sciences and then get in-depth disciplinary expertise during PhD studies. The completion of the total MSc curriculum may not be essential. Advantages and limitations of this concept will be discussed.

MiR-133b promotes neural plasticity and functional recovery after treatment of stroke with multipotent mesenchymal stromal cells in rats via transfer of exosome-enriched extracellular particles

PubMed Central

Xin, Hongqi; Li, Yi; Liu, Zhongwu; Wang, Xinli; Shang, Xia; Cui, Yisheng; Zhang, Zheng Gang; Chopp, Michael

2013-01-01

To test, in vivo, the hypothesis that exosomes from multipotent mesenchymal stromal cells (MSCs) mediate microRNA 133b (miR-133b) transfer which promotes neurological recovery from stroke, we employed knock-in and knock-down technologies to up-regulate or down-regulate the miR-133b level in MSCs (miR-133b+MSCs or miR-133b−MSCs) and their corresponding exosomes, respectively. Rats were subjected to middle cerebral artery occlusion (MCAo) and were treated with naïve MSCs, miR-133b+MSCs, or miR-133b−MSC at one day after MCAo. Compared with controls, rats receiving naïve MSC treatment significantly improved functional recovery, and exhibited increased axonal plasticity and neurite remodeling in the ischemic boundary zone (IBZ) at day 14 after MCAo. The outcomes were significantly enhanced with miR-133b+MSC treatment, and were significantly decreased with miR-133b−MSC treatment, compared to naïve MSC treatment. The miR-133b level in exosomes collected from the cerebral spinal fluid was significantly increased after miR-133b+MSC treatment, and was significantly decreased after miR-133b−MSC treatment at day 14 after MCAo, compared to naïve MSC treatment. Tagging exosomes with green fluorescent protein demonstrated that exosomes-enriched extracellular particles were released from MSCs and transferred to adjacent astrocytes and neurons. The expression of selective targets for miR-133b, connective tissue growth factor and ras homolog gene family member A, were significantly decreased in the IBZ after miR-133b+MSC treatment, while their expression remained at similar elevated levels after miR-133b−MSC treatment, compared to naïve MSC treatment. Collectively, our data suggest that exosomes from MSCs mediate the miR-133b transfer to astrocytes and neurons, which regulate gene expression, subsequently benefit neurite remodeling and functional recovery after stroke. PMID:23630198

Directly auto-transplanted mesenchymal stem cells induce bone formation in a ceramic bone substitute in an ectopic sheep model.

PubMed

Boos, Anja M; Loew, Johanna S; Deschler, Gloria; Arkudas, Andreas; Bleiziffer, Oliver; Gulle, Heinz; Dragu, Adrian; Kneser, Ulrich; Horch, Raymund E; Beier, Justus P

2011-06-01

Bone tissue engineering approaches increasingly focus on the use of mesenchymal stem cells (MSC). In most animal transplantation models MSC are isolated and expanded before auto cell transplantation which might be critical for clinical application in the future. Hence this study compares the potential of directly auto-transplanted versus in vitro expanded MSC with or without bone morphogenetic protein-2 (BMP-2) to induce bone formation in a large volume ceramic bone substitute in the sheep model. MSC were isolated from bone marrow aspirates and directly auto-transplanted or expanded in vitro and characterized using fluorescence activated cell sorting (FACS) and RT-PCR analysis before subcutaneous implantation in combination with BMP-2 and β-tricalcium phosphate/hydroxyapatite (β-TCP/HA) granules. Constructs were explanted after 1 to 12 weeks followed by histological and RT-PCR evaluation. Sheep MSC were CD29(+), CD44(+) and CD166(+) after selection by Ficoll gradient centrifugation, while directly auto-transplanted MSC-populations expressed CD29 and CD166 at lower levels. Both, directly auto-transplanted and expanded MSC, were constantly proliferating and had a decreasing apoptosis over time in vivo. Directly auto-transplanted MSC led to de novo bone formation in a heterotopic sheep model using a β-TCP/HA matrix comparable to the application of 60 μg/ml BMP-2 only or implantation of expanded MSC. Bone matrix proteins were up-regulated in constructs following direct auto-transplantation and in expanded MSC as well as in BMP-2 constructs. Up-regulation was detected using immunohistology methods and RT-PCR. Dense vascularization was demonstrated by CD31 immunohistology staining in all three groups. Ectopic bone could be generated using directly auto-transplanted or expanded MSC with β-TCP/HA granules alone. Hence BMP-2 stimulation might become dispensable in the future, thus providing an attractive, clinically feasible approach to bone tissue engineering. © 2011 The Authors Journal of Cellular and Molecular Medicine © 2011 Foundation for Cellular and Molecular Medicine/Blackwell Publishing Ltd.

Biomimetic Multispiked Connecting Ti-Alloy Scaffold Prototype for Entirely-Cementless Resurfacing Arthroplasty Endoprostheses—Exemplary Results of Implantation of the Ca-P Surface-Modified Scaffold Prototypes in Animal Model and Osteoblast Culture Evaluation

PubMed Central

Uklejewski, Ryszard; Rogala, Piotr; Winiecki, Mariusz; Tokłowicz, Renata; Ruszkowski, Piotr; Wołuń-Cholewa, Maria

2016-01-01

We present here—designed, manufactured, and tested by our research team—the Ti-alloy prototype of the multispiked connecting scaffold (MSC-Scaffold) interfacing the components of resurfacing arthroplasty (RA) endoprostheses with bone. The spikes of the MSC-Scaffold prototype mimic the interdigitations of the articular subchondral bone, which is the natural biostructure interfacing the articular cartilage with the periarticular trabecular bone. To enhance the osteoinduction/osteointegration potential of the MSC-Scaffold, the attempts to modify its bone contacting surfaces by the process of electrochemical cathodic deposition of Ca-P was performed with further immersion of the MSC-Scaffold prototypes in SBF in order to transform the amorphous calcium-phosphate coating in hydroxyapatite-like (HA-like) coating. The pilot experimental study of biointegration of unmodified and Ca-P surface-modified MSC-Scaffold prototypes was conducted in an animal model (swine) and in osteoblast cell culture. On the basis of a microscope-histological method the biointegration was proven by the presence of trabeculae in the interspike spaces of the MSC-Scaffold prototype on longitudinal and cross-sections of bone-implant specimens. The percentage of trabeculae in the area between the spikes of specimen containing Ca-P surface modified scaffold prototype observed in microCT reconstructions of the explanted joints was visibly higher than in the case of unmodified MSC-Scaffold prototypes. Significantly higher Alkaline Phosphatase (ALP) activity and the cellular proliferation in the case of Ca-P-modified MSC-Scaffold pre-prototypes, in comparison with unmodified pre-prototypes, was found in osteoblast cell cultures. The obtained results of experimental implantation in an animal model and osteoblast cell culture evaluations of Ca-P surface-modified and non-modified biomimetic MSC-Scaffold prototypes for biomimetic entirely-cementless RA endoprostheses indicate the enhancement of the osteoinduction/osteointegration potential by the Ca-P surface modification of the Ti-alloy MSC-Scaffold prototype. Planned further research on the prototype of this biomimetic MSC-Scaffold for a new generation of RA endoprostheses is also given. PMID:28773652

The Transcriptional Profile of Mesenchymal Stem Cell Populations in Primary Osteoporosis Is Distinct and Shows Overexpression of Osteogenic Inhibitors

PubMed Central

Benisch, Peggy; Schilling, Tatjana; Klein-Hitpass, Ludger; Frey, Sönke P.; Seefried, Lothar; Raaijmakers, Nadja; Krug, Melanie; Regensburger, Martina; Zeck, Sabine; Schinke, Thorsten; Amling, Michael; Ebert, Regina; Jakob, Franz

2012-01-01

Primary osteoporosis is an age-related disease characterized by an imbalance in bone homeostasis. While the resorptive aspect of the disease has been studied intensely, less is known about the anabolic part of the syndrome or presumptive deficiencies in bone regeneration. Multipotent mesenchymal stem cells (MSC) are the primary source of osteogenic regeneration. In the present study we aimed to unravel whether MSC biology is directly involved in the pathophysiology of the disease and therefore performed microarray analyses of hMSC of elderly patients (79–94 years old) suffering from osteoporosis (hMSC-OP). In comparison to age-matched controls we detected profound changes in the transcriptome in hMSC-OP, e.g. enhanced mRNA expression of known osteoporosis-associated genes (LRP5, RUNX2, COL1A1) and of genes involved in osteoclastogenesis (CSF1, PTH1R), but most notably of genes coding for inhibitors of WNT and BMP signaling, such as Sclerostin and MAB21L2. These candidate genes indicate intrinsic deficiencies in self-renewal and differentiation potential in osteoporotic stem cells. We also compared both hMSC-OP and non-osteoporotic hMSC-old of elderly donors to hMSC of ∼30 years younger donors and found that the transcriptional changes acquired between the sixth and the ninth decade of life differed widely between osteoporotic and non-osteoporotic stem cells. In addition, we compared the osteoporotic transcriptome to long term-cultivated, senescent hMSC and detected some signs for pre-senescence in hMSC-OP. Our results suggest that in primary osteoporosis the transcriptomes of hMSC populations show distinct signatures and little overlap with non-osteoporotic aging, although we detected some hints for senescence-associated changes. While there are remarkable inter-individual variations as expected for polygenetic diseases, we could identify many susceptibility genes for osteoporosis known from genetic studies. We also found new candidates, e.g. MAB21L2, a novel repressor of BMP-induced transcription. Such transcriptional changes may reflect epigenetic changes, which are part of a specific osteoporosis-associated aging process. PMID:23028809

Crystalline heterogeneities and instabilities in thermally convecting magma chamber

NASA Astrophysics Data System (ADS)

Culha, C.; Suckale, J.; Qin, Z.

2016-12-01

A volcanic vent can supply different densities of crystals over an eruption time period. This has been seen in Hawai'i's Kilauea Iki 1959 eruption; however it is not common for all Kilauea or basaltic eruptions. We ask the question: Under what conditions can homogenous magma chamber cultivate crystalline heterogeneities? In some laboratory experiments and numerical simulations, a horizontal variation is observed. The region where crystals reside is identified as a retention zone: convection velocity balances settling velocity. Simulations and experiments that observe retention zones assume crystals do not alter the convection in the fluid. However, a comparison of experiments and simulations of convecting magma with crystals suggest that large crystal volume densities and crystal sizes alter fluid flow considerably. We introduce a computational method that fully resolves the crystalline phase. To simulate basaltic magma chambers in thermal convection, we built a numerical solver of the Navier-Stoke's equation, continuity equation, and energy equation. The modeled magma is assumed to be a viscous, incompressible fluid with a liquid and solid phase. Crystals are spherical, rigid bodies. We create Rayleigh-Taylor instability through a cool top layer and hot bottom layer and update magma density while keeping crystal temperature and size constant. Our method provides a detailed picture of magma chambers, which we compare to other models and experiments to identify when and how crystals alter magma chamber convection. Alterations include stratification, differential settling and instabilities. These characteristics are dependent on viscosity, convection vigor, crystal volume density and crystal characteristics. We reveal that a volumetric crystal density variation may occur over an eruption time period, if right conditions are met to form stratifications and instabilities in magma chambers. These conditions are realistic for Kilauea Iki's 1959 eruption.

Monte Carlo calculations of electron beam quality conversion factors for several ion chamber types.

PubMed

Muir, B R; Rogers, D W O

2014-11-01

To provide a comprehensive investigation of electron beam reference dosimetry using Monte Carlo simulations of the response of 10 plane-parallel and 18 cylindrical ion chamber types. Specific emphasis is placed on the determination of the optimal shift of the chambers' effective point of measurement (EPOM) and beam quality conversion factors. The EGSnrc system is used for calculations of the absorbed dose to gas in ion chamber models and the absorbed dose to water as a function of depth in a water phantom on which cobalt-60 and several electron beam source models are incident. The optimal EPOM shifts of the ion chambers are determined by comparing calculations of R50 converted from I50 (calculated using ion chamber simulations in phantom) to R50 calculated using simulations of the absorbed dose to water vs depth in water. Beam quality conversion factors are determined as the calculated ratio of the absorbed dose to water to the absorbed dose to air in the ion chamber at the reference depth in a cobalt-60 beam to that in electron beams. For most plane-parallel chambers, the optimal EPOM shift is inside of the active cavity but different from the shift determined with water-equivalent scaling of the front window of the chamber. These optimal shifts for plane-parallel chambers also reduce the scatter of beam quality conversion factors, kQ, as a function of R50. The optimal shift of cylindrical chambers is found to be less than the 0.5 rcav recommended by current dosimetry protocols. In most cases, the values of the optimal shift are close to 0.3 rcav. Values of kecal are calculated and compared to those from the TG-51 protocol and differences are explained using accurate individual correction factors for a subset of ion chambers investigated. High-precision fits to beam quality conversion factors normalized to unity in a beam with R50 = 7.5 cm (kQ (')) are provided. These factors avoid the use of gradient correction factors as used in the TG-51 protocol although a chamber dependent optimal shift in the EPOM is required when using plane-parallel chambers while no shift is needed with cylindrical chambers. The sensitivity of these results to parameters used to model the ion chambers is discussed and the uncertainty related to the practical use of these results is evaluated. These results will prove useful as electron beam reference dosimetry protocols are being updated. The analysis of this work indicates that cylindrical ion chambers may be appropriate for use in low-energy electron beams but measurements are required to characterize their use in these beams.

SU‐C‐105‐05: Reference Dosimetry of High‐Energy Electron Beams with a Farmer‐Type Ionization Chamber

DOE Office of Scientific and Technical Information (OSTI.GOV)

Muir, B; Rogers, D

2013-06-15

Purpose: To investigate gradient effects and provide Monte Carlo calculated beam quality conversion factors to characterize the Farmer‐type NE2571 ion chamber for high‐energy reference dosimetry of clinical electron beams. Methods: The EGSnrc code system is used to calculate the absorbed dose to water and to the gas in a fully modeled NE2571 chamber as a function of depth in a water phantom. Electron beams incident on the surface of the phantom are modeled using realistic BEAMnrc accelerator simulations and electron beam spectra. Beam quality conversion factors are determined using calculated doses to water and to air in the chamber inmore » high‐energy electron beams and in a cobalt‐60 reference field. Calculated water‐to‐air stopping power ratios are employed for investigation of the overall ion chamber perturbation factor. Results: An upstream shift of 0.3–0.4 multiplied by the chamber radius, r-cav, both minimizes the variation of the overall ion chamber perturbation factor with depth and reduces the difference between the beam quality specifier (R{sub 5} {sub 0}) calculated using ion chamber simulations and that obtained with simulations of dose‐to‐water in the phantom. Beam quality conversion factors are obtained at the reference depth and gradient effects are optimized using a shift of 0.2r-cav. The photon‐electron conversion factor, k-ecal, amounts to 0.906 when gradient effects are minimized using the shift established here and 0.903 if no shift of the data is used. Systematic uncertainties in beam quality conversion factors are investigated and amount to between 0.4 to 1.1% depending on assumptions used. Conclusion: The calculations obtained in this work characterize the use of an NE2571 ion chamber for reference dosimetry of high‐energy electron beams. These results will be useful as the AAPM continues to review their reference dosimetry protocols.« less

Numerical simulation of magma chamber dynamics.

NASA Astrophysics Data System (ADS)

Longo, Antonella; Papale, Paolo; Montagna, Chiara Paola; Vassalli, Melissa; Giudice, Salvatore; Cassioli, Andrea

2010-05-01

Magma chambers are characterized by periodic arrivals of deep magma batches that give origin to complex patterns of magma convection and mixing, and modify the distribution of physical quantities inside the chamber. We simulate the transient, 2D, multi-component homogeneous dynamics in geometrically complex dyke+chamber systems, by means of GALES, a finite element parallel C++ code solving mass, momentum and energy equations for multi-component homogeneous gas-liquid (± crystals) mixtures in compressible-to-incompressible flow conditions. Code validation analysis includes several cases from the classical engineering literature, corresponding to a variety of subsonic to supersonic gas-liquid flow regimes (see http://www.pi.ingv.it/~longo/gales/gales.html). The model allows specification of the composition of the different magmas in the domain, in terms of ten major oxides plus the two volatile species H2O and CO2. Gas-liquid thermodynamics are modeled by using the compositional dependent, non-ideal model in Papale et al. (Chem.. Geol., 2006). Magma properties are defined in terms of local pressure, temperature, and composition including volatiles. Several applications are performed within domains characterized by the presence of one or more magma chambers and one or more dykes, with different geometries and characteristic size from hundreds of m to several km. In most simulations an initial compositional interface is placed at the top of a feeding dyke, or at larger depth, with the deeper magma having a lower density as a consequence of larger volatile content. The numerical results show complex patterns of magma refilling in the chamber, with alternating phases of magma ingression and magma sinking from the chamber into the feeding dyke. Intense mixing takes place in feeding dykes, so that the new magma entering the chamber is always a mixture of the deep and the initially resident magma. Buoyant plume rise occurs through the formation of complex convective patterns, giving origin to a density-stratified magma chamber.

Combustion-chamber Performance Characteristics of a Python Turbine-propeller Engine Investigated in Altitude Wind Tunnel

NASA Technical Reports Server (NTRS)

Campbell, Carl E

1951-01-01

Combustion-chamber performance characteristics of a Python turbine-propeller engine were determined from investigation of a complete engine over a range of engine speeds and shaft horsepowers at simulated altitudes. Results indicated the effect of engine operating conditions and altitude on combustion efficiency and combustion-chamber total pressure losses. Performance of this vaporizing type combustion chamber was also compared with several atomizing type combustion chambers. Over the range of test conditions investigated, combustion efficiency varied from approximately 0.95 to 0.99.

Mesenchymal stem cells expressing insulin-like growth factor-I (MSCIGF) promote fracture healing and restore new bone formation in Irs1 knockout mice: analyses of MSCIGF autocrine and paracrine regenerative effects.

PubMed

Granero-Moltó, Froilán; Myers, Timothy J; Weis, Jared A; Longobardi, Lara; Li, Tieshi; Yan, Yun; Case, Natasha; Rubin, Janet; Spagnoli, Anna

2011-10-01

Failures of fracture repair (nonunions) occur in 10% of all fractures. The use of mesenchymal stem cells (MSC) in tissue regeneration appears to be rationale, safe, and feasible. The contributions of MSC to the reparative process can occur through autocrine and paracrine effects. The primary objective of this study is to find a novel mean, by transplanting primary cultures of bone marrow-derived MSCs expressing insulin-like growth factor-I (MSC(IGF)), to promote these seed-and-soil actions of MSC to fully implement their regenerative abilities in fracture repair and nonunions. MSC(IGF) or traceable MSC(IGF)-Lac-Z were transplanted into wild-type or insulin-receptor-substrate knockout (Irs1(-/-)) mice with a stabilized tibia fracture. Healing was assessed using biomechanical testing, microcomputed tomography (μCT), and histological analyses. We found that systemically transplanted MSC(IGF) through autocrine and paracrine actions improved the fracture mechanical strength and increased new bone content while accelerating mineralization. We determined that IGF-I adapted the response of transplanted MSC(IGF) to promote their differentiation into osteoblasts. In vitro and in vivo studies showed that IGF-I-induced osteoglastogenesis in MSCs was dependent of an intact IRS1-PI3K signaling. Furthermore, using Irs1(-/-) mice as a nonunion fracture model through altered IGF signaling, we demonstrated that the autocrine effect of IGF-I on MSC restored the fracture new bone formation and promoted the occurrence of a well-organized callus that bridged the gap. A callus that was basically absent in Irs1(-/-) left untransplanted or transplanted with MSCs. We provided evidence of effects and mechanisms for transplanted MSC(IGF) in fracture repair and potentially to treat nonunions. Copyright © 2011 AlphaMed Press.

Extracellular Vesicles Released from Human Umbilical Cord-Derived Mesenchymal Stromal Cells Prevent Life-Threatening Acute Graft-Versus-Host Disease in a Mouse Model of Allogeneic Hematopoietic Stem Cell Transplantation.

PubMed

Wang, Li; Gu, Zhenyang; Zhao, Xiaoli; Yang, Nan; Wang, Feiyan; Deng, Ailing; Zhao, Shasha; Luo, Lan; Wei, Huaping; Guan, Lixun; Gao, Zhe; Li, Yonghui; Wang, Lili; Liu, Daihong; Gao, Chunji

2016-12-15

Mesenchymal stromal cells (MSCs) are attractive agents for the prophylaxis of acute graft-versus-host disease (aGVHD) after allogeneic hematopoietic stem cell transplantation (allo-HSCT). However, safety concerns remain about their clinical application. In this study, we explored whether extracellular vesicles released from human umbilical cord-derived MSCs (hUC-MSC-EVs) could prevent aGVHD in a mouse model of allo-HSCT. hUC-MSC-EVs were intravenously administered to recipient mice on days 0 and 7 after allo-HSCT, and the prophylactic effects of hUC-MSC-EVs were assessed by observing the in vivo manifestations of aGVHD, histologic changes in target organs, and recipient mouse survival. We evaluated the effects of hUC-MSC-EVs on immune cells and inflammatory cytokines by flow cytometry and ProcartaPlex™ Multiplex Immunoassays, respectively. The in vitro effects of hUC-MSC-EVs were determined by mitogen-induced proliferation assays. hUC-MSC-EVs alleviated the in vivo manifestations of aGVHD and the associated histologic changes and significantly reduced the mortality of the recipient mice. Recipients treated with hUC-MSC-EVs had significantly lower frequencies and absolute numbers of CD3 + CD8 + T cells; reduced serum levels of IL-2, TNF-α, and IFN-γ; a higher ratio of CD3 + CD4 + and CD3 + CD8 + T cells; and higher serum levels of IL-10. An in vitro experiment demonstrated that hUC-MSC-EVs inhibited the mitogen-induced proliferation of splenocytes in a dose-dependent manner, and the cytokine changes were similar to those observed in vivo. This study indicated that hUC-MSC-EVs can prevent life-threatening aGVHD by modulating immune responses. These data provide the first evidence that hUC-MSC-EVs represent an ideal alternative in the prophylaxis of aGVHD after allo-HSCT.

Human Umbilical Cord Mesenchymal Stem Cells: Subpopulations and Their Difference in Cell Biology and Effects on Retinal Degeneration in RCS Rats.

PubMed

Wang, L; Li, P; Tian, Y; Li, Z; Lian, C; Ou, Q; Jin, C; Gao, F; Xu, J-Y; Wang, J; Wang, F; Zhang, J; Zhang, J; Li, W; Tian, H; Lu, L; Xu, G-T

2017-01-01

Human umbilical cord mesenchymal stem cells (hUC-MSCs) are potential candidates for treating retinal degeneration (RD). To further study the biology and therapeutic effects of the hUC-MSCs on retinal degeneration. Two hUC-MSC subpopulations, termed hUC-MSC1 and hUC-MSC2, were isolated by single-cell cloning method and their therapeutic functions were compared in RCS rat, a RD model. Although both subsets satisfied the basic requirements for hUC-MSCs, they were significantly different in morphology, proliferation rate, differentiation capacity, phenotype and gene expression. Furthermore, only the smaller, fibroblast-like, faster growing subset hUC-MSC1 displayed stronger colony forming potential as well as adipogenic and osteogenic differentiation capacities. When the two subsets were respectively transplanted into the subretinal spaces of RCS rats, both subsets survived, but only hUC-MSC1 expressed RPE cell markers Bestrophin and RPE65. More importantly, hUC-MSC1 showed stronger rescue effect on the retinal function as indicated by the higher b-wave amplitude on ERG examination, thicker retinal nuclear layer, and decreased apoptotic photoreceptors. When both subsets were treated with interleukin-6, mimicking the inflammatory environment when the cells were transplanted into the eyes with degenerated retina, hUC-MSC1 expressed much higher levels of trophic factors in comparison with hUC-MSC2. The data here, in addition to prove the heterogeneity of hUC-MSCs, confirmed that the stronger therapeutic effects of hUC-MSC1 were attributed to its stronger anti-apoptotic effect, paracrine of trophic factors and potential RPE cell differentiation capacity. Thus, the subset hUC-MSC1, not the other subset or the ungrouped hUC-MSCs should be used for effective treatment of RD. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Mesenchymal Stromal Cells Modulate Monocytes Trafficking in Coxsackievirus B3‐Induced Myocarditis

PubMed Central

Miteva, Kapka; Pappritz, Kathleen; El‐Shafeey, Muhammad; Dong, Fengquan; Ringe, Jochen; Tschöpe, Carsten

2017-01-01

Abstract Mesenchymal stromal cell (MSC) application in Coxsackievirus B3 (CVB3)‐induced myocarditis reduces myocardial inflammation and fibrosis, exerts prominent extra‐cardiac immunomodulation, and improves heart function. Although the abovementioned findings demonstrate the benefit of MSC application, the mechanism of the MSC immunomodulatory effects leading to a final cardioprotective outcome in viral myocarditis remains poorly understood. Monocytes are known to be a trigger of myocardial tissue inflammation. The present study aims at investigating the direct effect of MSC on the mobilization and trafficking of monocytes to the heart in CVB3‐induced myocarditis. One day post CVB3 infection, C57BL/6 mice were intravenously injected with 1 x 106 MSC and sacrificed 6 days later for molecular biology and flow cytometry analysis. MSC application reduced the severity of myocarditis, and heart and blood pro‐inflammatory Ly6Chigh and Ly6Cmiddle monocytes, while those were retained in the spleen. Anti‐inflammatory Ly6Clow monocytes increased in the blood, heart, and spleen of MSC‐treated CVB3 mice. CVB3 infection induced splenic myelopoiesis, while MSC application slightly diminished the spleen myelopoietic activity in CVB3 mice. Left ventricular (LV) mRNA expression of the chemokines monocyte chemotactic protein‐1 (MCP)−1, MCP‐3, CCL5, the adhesion molecules intercellular adhesion molecule‐1, vascular cell adhesion molecule‐1, the pro‐inflammatory cytokines interleukin‐6, interleukin‐12, tumor necrosis factor‐α, the pro‐fibrotic transforming growth factorβ1, and circulating MCP‐1 and MCP‐3 levels decreased in CVB3 MSC mice, while LV stromal cell‐derived factor‐1α RNA expression and systemic levels of fractalkine were increased in CVB3 MSC mice. MSC application in CVB3‐induced myocarditis modulates monocytes trafficking to the heart and could be a promising strategy for the resolution of cardiac inflammation and prevention of the disease progression. Stem Cells Translational Medicine 2017;6:1249–1261 PMID:28186704

Anti-Donor Immune Responses Elicited by Allogeneic Mesenchymal Stem Cells and Their Extracellular Vesicles: Are We Still Learning?

PubMed Central

Lohan, Paul; Treacy, Oliver; Griffin, Matthew D.; Ritter, Thomas; Ryan, Aideen E.

2017-01-01

Mesenchymal stromal cells (MSC) have been used to treat a broad range of disease indications such as acute and chronic inflammatory disorders, autoimmune diseases, and transplant rejection due to their potent immunosuppressive/anti-inflammatory properties. The breadth of their usage is due in no small part to the vast quantity of published studies showing their ability to modulate multiple immune cell types of both the innate and adaptive immune response. While patient-derived (autologous) MSC may be the safer choice in terms of avoiding unwanted immune responses, factors including donor comorbidities may preclude these cells from use. In these situations, allogeneic MSC derived from genetically unrelated individuals must be used. While allogeneic MSC were initially believed to be immune-privileged, substantial evidence now exists to prove otherwise with multiple studies documenting specific cellular and humoral immune responses against donor antigens following administration of these cells. In this article, we will review recent published studies using non-manipulated, inflammatory molecule-activated (licensed) and differentiated allogeneic MSC, as well as MSC extracellular vesicles focusing on the immune responses to these cells and whether or not such responses have an impact on allogeneic MSC-mediated safety and efficacy. PMID:29225601

Mesenchymal Stem Cell Derived Secretome and Extracellular Vesicles for Acute Lung Injury and Other Inflammatory Lung Diseases

PubMed Central

Monsel, Antoine; Zhu, Ying-gang; Gudapati, Varun; Lim, Hyungsun; Lee, Jae W.

2017-01-01

Introduction Acute respiratory distress syndrome is a major cause of respiratory failure in critically ill patients. Despite extensive research into its pathophysiology, mortality remains high. No effective pharmacotherapy exists. Based largely on numerous preclinical studies, administration of mesenchymal stem or stromal cell (MSC) as a therapeutic for acute lung injury holds great promise, and clinical trials are currently underway. However, concern for the use of stem cells, specifically the risk of iatrogenic tumor formation, remains unresolved. Accumulating evidence now suggest that novel cell-free therapies including MSC-derived conditioned medium and extracellular vesicles released from MSCs might constitute compelling alternatives. Areas covered The current review summarizes the preclinical studies testing MSC conditioned medium and/or MSC extracellular vesicles as treatment for acute lung injury and other inflammatory lung diseases. Expert opinion While certain logistical obstacles limit the clinical applications of MSC conditioned medium such as the volume required for treatment, the therapeutic application of MSC extracellular vesicles remains promising, primarily due to ability of extracellular vesicles to maintain the functional phenotype of the parent cell. However, utilization of MSC extracellular vesicles will require large-scale production and standardization concerning identification, characterization and quantification. PMID:27011289

Mesenchymal Stem Cells Respond to Hypoxia by Increasing Diacylglycerols.

PubMed

Lakatos, Kinga; Kalomoiris, Stefanos; Merkely, Béla; Nolta, Jan A; Fierro, Fernando A

2016-02-01

Mesenchymal stem cells (MSC) are currently being tested clinically for a plethora of conditions, with most approaches relying on the secretion of paracrine signals by MSC to modulate the immune system, promote wound healing, and induce angiogenesis. Hypoxia has been shown to affect MSC proliferation, differentiation, survival and secretory profile. Here, we investigate changes in the lipid composition of human bone marrow-derived MSC after exposure to hypoxia. Using mass spectrometry, we compared the lipid profiles of MSC derived from five different donors, cultured for two days in either normoxia (control) or hypoxia (1% oxygen). Hypoxia induced a significant increase of total triglycerides, fatty acids and diacylglycerols (DG). Remarkably, reduction of DG levels using the phosphatidylcholine-specific phospholipase C inhibitor D609 inhibited the secretion of VEGF and Angiopoietin-2, but increased the secretion of interleukin-8, without affecting significantly their respective mRNA levels. Functionally, incubation of MSC in hypoxia with D609 inhibited the potential of the cells to promote migration of human endothelial cells in a wound/scratch assay. Hence, we show that hypoxia induces in MSC an increase of DG that may affect the angiogenic potential of these cells. © 2015 Wiley Periodicals, Inc.

Interactions of Human Endothelial and Multipotent Mesenchymal Stem Cells in Cocultures

PubMed Central

Ern, Christina; Krump-Konvalinkova, Vera; Docheva, Denitsa; Schindler, Stefanie; Rossmann, Oliver; Böcker, Wolfgang; Mutschler, Wolf; Schieker, Matthias

2010-01-01

Current strategies for tissue engineering of bone rely on the implantation of scaffolds, colonized with human mesenchymal stem cells (hMSC), into a recipient. A major limitation is the lack of blood vessels. One approach to enhance the scaffold vascularisation is to supply the scaffolds with endothelial cells (EC). The main goal of this study was to establish a coculture system of hMSC and EC for the purposes of bone tissue engineering. Therefore, the cell behaviour, proliferation and differentiation capacity in various cell culture media as well as cell interactions in the cocultures were evaluated. The differentiation capacity of hMSC along osteogenic, chondrogenic, and adipogenic lineage was impaired in EC medium while in a mixed EC and hMSC media, hMSC maintained osteogenic differentiation. In order to identify and trace EC in the cocultures, EC were transduced with eGFP. Using time-lapse imaging, we observed that hMSC and EC actively migrated towards cells of their own type and formed separate clusters in long term cocultures. The scarcity of hMSC and EC contacts in the cocultures suggest the influence of growth factor-mediated cell interactions and points to the necessity of further optimization of the coculture conditions. PMID:21625373

Numerical and experimental analysis of heat transfer in injector plate of hydrogen peroxide hybrid rocket motor

NASA Astrophysics Data System (ADS)

Cai, Guobiao; Li, Chengen; Tian, Hui

2016-11-01

This paper is aimed to analyze heat transfer in injector plate of hydrogen peroxide hybrid rocket motor by two-dimensional axisymmetric numerical simulations and full-scale firing tests. Long-time working, which is an advantage of hybrid rocket motor over conventional solid rocket motor, puts forward new challenges for thermal protection. Thermal environments of full-scale hybrid rocket motors designed for long-time firing tests are studied through steady-state coupled numerical simulations of flow field and heat transfer in chamber head. The motor adopts 98% hydrogen peroxide (98HP) oxidizer and hydroxyl-terminated poly-butadiene (HTPB) based fuel as the propellants. Simulation results reveal that flowing liquid 98HP in head oxidizer chamber could cool the injector plate of the motor. The cooling of 98HP is similar to the regenerative cooling in liquid rocket engines. However, the temperature of the 98HP in periphery portion of the head oxidizer chamber is higher than its boiling point. In order to prevent the liquid 98HP from unexpected decomposition, a thermal protection method for chamber head utilizing silica-phenolics annular insulating board is proposed. The simulation results show that the annular insulating board could effectively decrease the temperature of the 98HP in head oxidizer chamber. Besides, the thermal protection method for long-time working hydrogen peroxide hybrid rocket motor is verified through full-scale firing tests. The ablation of the insulating board in oxygen-rich environment is also analyzed.

The effect of municipal sludge compost on the mobility and bioavailability of Cd in a sierozem-wheat system in an arid region northwest of China.

PubMed

Liu, Zheng; Yang, Yang; Bai, Ying; Huang, Yu; Nan, Zhongren; Zhao, Chuanyan; Ma, Jianmin; Wang, Houcheng

2016-10-01

The effect of sewage sludge on the mobility and the bioavailability of trace metals in plant-soil systems have aroused wide interested and been widely explored. Based on a wheat-cultivating experiment, the effect of municipal sludge compost (MSC) on the mobility and bioavailability of Cd in a soil-wheat system was studied. With the application of MSC, soil organic matter (SOM), total nitrogen (TN), and total phosphorus (TP) in the soil increased significantly, while concentrations of trace metals (Cu, Zn, Ni, Pb, Cd) were below the China's minimum thresholds. The application of MSC could improve wheat growth. The application of MSC at the rate of 0.5 % had no significant effect on the chemical fraction distribution of Cd in soil. In two soil treatments, Cd mainly existed in the labile chemical fractions (exchangeable chemical fraction (EXCF) and carbonate chemical fraction (CABF)). However, the application of MSC could reduce accumulation of Cd by wheat. Cd contents in each part of the MSC-applied wheat were significantly less than that of non-MSC-applied wheat. In the tested soils, the extractable concentrations decreased in the order: EDTA > MgCl 2 ≈ NH 4 OAc > DTPA. There were no significant differences between soil treatments in the amounts of extractable Cd when the extraction was done under neutral conditions, although significant differences were observed when the extraction was done under alkaline conditions. In this study, the DTPA extraction procedure provided a good indication of Cd bioavailability. Our results suggest that, in the short term at least, amending soils with MSC may benefit crop dry matter production while not increasing the risk of human exposure to Cd through consumption of wheat grown on MSC-amended soils.

Defining the role of mesenchymal stromal cells on the regulation of matrix metalloproteinases in skeletal muscle cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sassoli, Chiara; Nosi, Daniele; Tani, Alessia

Recent studies indicate that mesenchymal stromal cell (MSC) transplantation improves healing of injured and diseased skeletal muscle, although the mechanisms of benefit are poorly understood. In the present study, we investigated whether MSCs and/or their trophic factors were able to regulate matrix metalloproteinase (MMP) expression and activity in different cells of the muscle tissue. MSCs in co-culture with C2C12 cells or their conditioned medium (MSC-CM) up-regulated MMP-2 and MMP-9 expression and function in the myoblastic cells; these effects were concomitant with the down-regulation of the tissue inhibitor of metalloproteinases (TIMP)-1 and -2 and with increased cell motility. In the singlemore » muscle fiber experiments, MSC-CM administration increased MMP-2/9 expression in Pax-7{sup +} satellite cells and stimulated their mobilization, differentiation and fusion. The anti-fibrotic properties of MSC-CM involved also the regulation of MMPs by skeletal fibroblasts and the inhibition of their differentiation into myofibroblasts. The treatment with SB-3CT, a potent MMP inhibitor, prevented in these cells, the decrease of α-smooth actin and type-I collagen expression induced by MSC-CM, suggesting that MSC-CM could attenuate the fibrogenic response through mechanisms mediated by MMPs. Our results indicate that growth factors and cytokines released by these cells may modulate the fibrotic response and improve the endogenous mechanisms of muscle repair/regeneration. - Highlights: • MSC-CM contains paracrine factors that up-regulate MMP expression and function in different skeletal muscle cells. • MSC-CM promotes myoblast and satellite cell migration, proliferation and differentiation. • MSC-CM negatively interferes with fibroblast-myoblast transition in primary skeletal fibroblasts. • Paracrine factors from MSCs modulate the fibrotic response and improve the endogenous mechanisms of muscle regeneration.« less

Distinct spatial distribution of microglia and macrophages following mesenchymal stem cell implantation in mouse brain.

PubMed

Le Blon, Debbie; Hoornaert, Chloé; Daans, Jasmijn; Santermans, Eva; Hens, Niel; Goossens, Herman; Berneman, Zwi; Ponsaerts, Peter

2014-09-01

Although implantation of cellular material in the central nervous system (CNS) is a key direction in CNS regenerative medicine, this approach is currently limited by the occurrence of strong endogenous immune cell responses. In a model of mesenchymal stem cell (MSC) grafting in the CNS of immune-competent mice, we previously described that MSC grafts become highly surrounded and invaded by Iba1(+) myeloid cells (microglia and/or macrophages). Here, following grafting of blue fluorescent protein (BFP)-expressing MSC in the CNS of CX3CR1(+/-) and CX3CR1(-/-) mice, our results indicate: (1) that the observed inflammatory response is independent of the fractalkine signalling axis, and (2) that a significant spatial distribution of Iba1(+) inflammatory cells occurs, in which Iba1(+) CX3CR1(+) myeloid cells mainly surround the MSC graft and Iba1(+) CX3CR1(-) myeloid cells mainly invade the graft at 10 days post transplantation. Although Iba1(+) CX3CR1(+) myeloid cells are considered to be of resident microglial origin, Iba1(+) CX3CR1(-) myeloid cells are most likely of peripheral monocyte/macrophage origin. In order to confirm the latter, we performed MSC-BFP grafting experiments in the CNS of eGFP(+) bone marrow chimeric C57BL/6 mice. Analysis of MSC-BFP grafts in the CNS of these mice confirmed our observation that peripheral monocytes/macrophages invade the MSC graft and that resident microglia surround the MSC graft site. Furthermore, analysis of major histocompatibility complex class II (MHCII) expression revealed that mainly macrophages, but not microglia, express this M1 pro-inflammatory marker in the context of MSC grafting in the CNS. These results again highlight the complexity of cell implantation immunology in the CNS.

Equine platelet lysate as an alternative to fetal bovine serum in equine mesenchymal stromal cell culture - too much of a good thing?

PubMed

Russell, K A; Koch, T G

2016-03-01

Multipotent mesenchymal stromal cells (MSC) are often culture-expanded in vitro. Presently, expansion medium (EM) for MSC is supplemented with fetal bovine serum (FBS). However, increasing cost, variable composition and potential risks associated with bovine antigens call for alternatives. Platelet lysate (PL) has shown promise as an alternative supplement. To determine how equine umbilical cord blood (CB) MSC proliferate in EM enriched with PL or FBS at various concentrations. Randomised dose escalation study. Platelet concentrate was generated from 5 equine whole blood samples through a double centrifugation method and standardised to 1 × 10(12) platelets/l prior to a freeze/thaw cycle to produce PL. Pooled PL or pooled FBS was added to EM at concentrations of 5% to 60%. Proliferation of 4 equine CB-MSC cultures was determined after 4 days using a resazurin semiquantitative assay. Cord blood-MSC proliferated with a dose-dependent response with no significant difference found between PL and FBS up to a 30% concentration. Beyond 30%, proliferation fell in the PL-cultured cells, while continued dose-dependent proliferation was noted in the FBS-cultured cells. Despite reduced cell numbers in high PL concentrations, live/dead staining revealed that adherent cells remained viable. Expansion medium enriched with PL can support short-term equine CB-MSC proliferation at conventional culture concentrations. Based on the unexpected suppression of CB-MSC at higher PL concentrations, an in vivo dose study is indicated to investigate if combinational therapies of CB-MSC and platelet-rich plasma are associated with synergistic or antagonistic effect on CB-MSC function. © 2015 EVJ Ltd.

Selective sensitiveness of mesenchymal stem cells to shock waves leads to anticancer effect in human cancer cell co-cultures.

PubMed

Foglietta, Federica; Duchi, Serena; Canaparo, Roberto; Varchi, Greta; Lucarelli, Enrico; Dozza, Barbara; Serpe, Loredana

2017-03-15

Mesenchymal stem cells (MSC) possess the distinctive feature of homing in on and engrafting into the tumor stroma making their therapeutic applications in cancer treatment very promising. Research into new effectors and external stimuli, which can selectively trigger the release of cytotoxic species from MSC toward the cancer cells, significantly raises their potential. Shock waves (SW) have recently gained recognition for their ability to induce specific biological effects, such as the local generation of cytotoxic reactive oxygen species (ROS) in a non-invasive and tunable manner. We thus investigate whether MSC are able to generate ROS and, in turn, affect cancer cell growth when in co-culture with human glioblastoma (U87) or osteosarcoma (U2OS) cells and exposed to SW. MSC were found to be the cell line that was most sensitive to SW treatment as shown by SW-induced ROS production and cytotoxicity. Notably, U87 and U2OS cancer cell growth was unaffected by SW exposure. However, significant decreases in cancer cell growth, 1.8 fold for U87 and 2.3 fold for U2OS, were observed 24h after the SW treatment of MSC co-cultures with cancer cells. The ROS production induced in MSC by SW exposure was then responsible for lipid peroxidation and cell death in U87 and U2OS cells co-cultured with MSC. This experiment highlights the unique ability of MSC to generate ROS upon SW treatment and induce the cell death of co-cultured cancer cells. SW might therefore be proposed as an innovative tool for MSC-mediated cancer treatment. Copyright © 2017 Elsevier Inc. All rights reserved.

Combined administration of mesenchymal stem cells overexpressing IGF-1 and HGF enhances neovascularization but moderately improves cardiac regeneration in a porcine model.

PubMed

Gómez-Mauricio, Guadalupe; Moscoso, Isabel; Martín-Cancho, María-Fernanda; Crisóstomo, Verónica; Prat-Vidal, Cristina; Báez-Díaz, Claudia; Sánchez-Margallo, Francisco M; Bernad, Antonio

2016-07-16

Insulin-like growth factor 1 (IGF-1) and hepatocyte growth factor (HGF) are among the most promising growth factors for promoting cardiorepair. Here, we evaluated the combination of cell- and gene-based therapy using mesenchymal stem cells (MSC) genetically modified to overexpress IGF-1 or HGF to treat acute myocardial infarction (AMI) in a porcine model. Pig MSC from adipose tissue (paMSC) were genetically modified for evaluation of different therapeutic strategies to improve AMI treatment. Three groups of infarcted Large White pigs were compared (I, control, non-transplanted; II, transplanted with paMSC-GFP (green fluorescent protein); III, transplanted with paMSC-IGF-1/HGF). Cardiac function was evaluated non-invasively using magnetic resonance imaging (MRI) for 1 month. After euthanasia and sampling of the animal, infarcted areas were studied by histology and immunohistochemistry. Intramyocardial transplant in a porcine infarct model demonstrated the safety of paMSC in short-term treatments. Treatment with paMSC-IGF-1/HGF (1:1) compared with the other groups showed a clear reduction in inflammation in some sections analyzed and promoted angiogenic processes in ischemic tissue. Although cardiac function parameters were not significantly improved, cell retention and IGF-1 overexpression was confirmed within the myocardium. The simultaneous administration of IGF-1- and HGF-overexpressing paMSC appears not to promote a synergistic effect or effective repair. The combined enhancement of neovascularization and fibrosis in paMSC-IGF-1/HGF-treated animals nonetheless suggests that sustained exposure to high IGF-1 + HGF levels promotes beneficial as well as deleterious effects that do not improve overall cardiac regeneration.

Human mesenchymal stem cells suppress donor CD4(+) T cell proliferation and reduce pathology in a humanized mouse model of acute graft-versus-host disease.

PubMed

Tobin, L M; Healy, M E; English, K; Mahon, B P

2013-05-01

Acute graft-versus-host disease (aGVHD) is a life-threatening complication following allogeneic haematopoietic stem cell transplantation (HSCT), occurring in up to 30-50% of patients who receive human leucocyte antigen (HLA)-matched sibling transplants. Current therapies for steroid refractory aGVHD are limited, with the prognosis of patients suboptimal. Mesenchymal stem or stromal cells (MSC), a heterogeneous cell population present in many tissues, display potent immunomodulatory abilities. Autologous and allogeneic ex-vivo expanded human MSC have been utilized to treat aGVHD with promising results, but the mechanisms of therapeutic action remain unclear. Here a robust humanized mouse model of aGVHD based on delivery of human peripheral blood mononuclear cells (PBMC) to non-obese diabetic (NOD)-severe combined immunodeficient (SCID) interleukin (IL)-2rγ(null) (NSG) mice was developed that allowed the exploration of the role of MSC in cell therapy. MSC therapy resulted in the reduction of liver and gut pathology and significantly increased survival. Protection was dependent upon the timing of MSC therapy, with conventional MSC proving effective only after delayed administration. In contrast, interferon (IFN)-γ-stimulated MSC were effective when delivered with PBMC. The beneficial effect of MSC therapy in this model was not due to the inhibition of donor PBMC chimerism, as CD45(+) and T cells engrafted successfully in this model. MSC therapy did not induce donor T cell anergy, FoxP3(+) T regulatory cells or cause PBMC apoptosis in this model; however, it was associated with the direct inhibition of donor CD4(+) T cell proliferation and reduction of human tumour necrosis factor-α in serum. © 2012 British Society for Immunology.

Different wound healing properties of dermis, adipose, and gingiva mesenchymal stromal cells.

PubMed

Boink, Mireille A; van den Broek, Lenie J; Roffel, Sanne; Nazmi, Kamran; Bolscher, Jan G M; Gefen, Amit; Veerman, Enno C I; Gibbs, Susan

2016-01-01

Oral wounds heal faster and with better scar quality than skin wounds. Deep skin wounds where adipose tissue is exposed, have a greater risk of forming hypertrophic scars. Differences in wound healing and final scar quality might be related to differences in mesenchymal stromal cells (MSC) and their ability to respond to intrinsic (autocrine) and extrinsic signals, such as human salivary histatin, epidermal growth factor, and transforming growth factor beta1. Dermis-, adipose-, and gingiva-derived MSC were compared for their regenerative potential with regards to proliferation, migration, and matrix contraction. Proliferation was assessed by cell counting and migration using a scratch wound assay. Matrix contraction and alpha smooth muscle actin was assessed in MSC populated collagen gels, and also in skin and gingival full thickness tissue engineered equivalents (reconstructed epithelium on MSC populated matrix). Compared to skin-derived MSC, gingiva MSC showed greater proliferation and migration capacity, and less matrix contraction in full thickness tissue equivalents, which may partly explain the superior oral wound healing. Epidermal keratinocytes were required for enhanced adipose MSC matrix contraction and alpha smooth muscle actin expression, and may therefore contribute to adverse scarring in deep cutaneous wounds. Histatin enhanced migration without influencing proliferation or matrix contraction in all three MSC, indicating that salivary peptides may have a beneficial effect on wound closure in general. Transforming growth factor beta1 enhanced contraction and alpha smooth muscle actin expression in all three MSC types when incorporated into collagen gels. Understanding the mechanisms responsible for the superior oral wound healing will aid us to develop advanced strategies for optimal skin regeneration, wound healing and scar formation. © 2015 by the Wound Healing Society.

CD146/MCAM defines functionality of human bone marrow stromal stem cell populations.

PubMed

Harkness, Linda; Zaher, Walid; Ditzel, Nicholas; Isa, Adiba; Kassem, Moustapha

2016-01-11

Identification of surface markers for prospective isolation of functionally homogenous populations of human skeletal (stromal, mesenchymal) stem cells (hMSCs) is highly relevant for cell therapy protocols. Thus, we examined the possible use of CD146 to subtype a heterogeneous hMSC population. Using flow cytometry and cell sorting, we isolated two distinct hMSC-CD146(+) and hMSC-CD146(-) cell populations from the telomerized human bone marrow-derived stromal cell line (hMSC-TERT). Cells were examined for differences in their size, shape and texture by using high-content analysis and additionally for their ability to differentiate toward osteogenesis in vitro and form bone in vivo, and their migrational ability in vivo and in vitro was investigated. In vitro, the two cell populations exhibited similar growth rate and differentiation capacity to osteoblasts and adipocytes on the basis of gene expression and protein production of lineage-specific markers. In vivo, hMSC-CD146(+) and hMSC-CD146(-) cells formed bone and bone marrow organ when implanted subcutaneously in immune-deficient mice. Bone was enriched in hMSC-CD146(-) cells (12.6 % versus 8.1 %) and bone marrow elements enriched in implants containing hMSC-CD146(+) cells (0.5 % versus 0.05 %). hMSC-CD146(+) cells exhibited greater chemotactic attraction in a transwell migration assay and, when injected intravenously into immune-deficient mice following closed femoral fracture, exhibited wider tissue distribution and significantly increased migration ability as demonstrated by bioluminescence imaging. Our studies demonstrate that CD146 defines a subpopulation of hMSCs capable of bone formation and in vivo trans-endothelial migration and thus represents a population of hMSCs suitable for use in clinical protocols of bone tissue regeneration.

Direct head-to-head comparison of cationic liposome-mediated gene delivery to mesenchymal stem/stromal cells of different human sources: a comprehensive study.

PubMed

Boura, Joana S; Santos, Francisco Dos; Gimble, Jeffrey M; Cardoso, Carla M P; Madeira, Catarina; Cabral, Joaquim M S; Silva, Cláudia Lobato da

2013-02-01

Nonviral gene delivery to human mesenchymal stem/stromal cells (MSC) can be considered a very promising strategy to improve their intrinsic features, amplifying the therapeutic potential of these cells for clinical applications. In this work, we performed a comprehensive comparison of liposome-mediated gene transfer efficiencies to MSC derived from different human sources-bone marrow (BM MSC), adipose tissue-derived cells (ASC), and umbilical cord matrix (UCM MSC). The results obtained using a green fluorescent protein (GFP)-encoding plasmid indicated that MSC isolated from BM and UCM are more amenable to genetic modification when compared to ASC as they exhibited superior levels of viable, GFP(+) cells 48 hr post-transfection, 58 ± 7.1% and 54 ± 3.8%, respectively, versus 33 ± 4.7%. For all cell sources, high cell recoveries (≈50%) and viabilities (>85%) were achieved, and the transgene expression was maintained for 10 days. Levels of plasmid DNA uptake, as well as kinetics of transgene expression and cellular division, were also determined. Importantly, modified cells were found to retain their characteristic immunophenotypic profile and multilineage differentiation capacity. By using the lipofection protocol optimized herein, we were able to maximize transfection efficiencies to human MSC (maximum of 74% total GFP(+) cells) and show that lipofection is a promising transfection strategy for MSC genetic modification, especially when a transient expression of a therapeutic gene is required. Importantly, we also clearly demonstrated that intrinsic features of MSC from different sources should be taken into consideration when developing and optimizing strategies for MSC engineering with a therapeutic gene.

Effects of platelet rich plasma and chondrocyte co-culture on MSC chondrogenesis, hypertrophy and pathological responses

PubMed Central

Ramezanifard, Rouhallah; Kabiri, Mahboubeh; Hanaee Ahvaz, Hana

2017-01-01

Regarding the inadequate healing capability of cartilage tissue, cell-based therapy is making the future of cartilage repair and regeneration. Mesenchymal stem cells (MSC) have shown great promise in cartilage regeneration. However, a yet-unresolved issue is the emergence of hypertrophic and pathologic markers during in vitro MSC chondrogenesis. Articular chondrocytes (AC) can suppress the undesired hypertrophy when co-cultured with MSC. On the other hand, platelet rich plasma (PRP), is considered potentially effective for cartilage repair and in-vitro chondrogenesis. We thus aimed to harness chondro-promotive effects of PRP and hypertrophic-suppressive effects of AC:MSC co-culture to achieve a more functional cartilage neo-tissue. We used PRP or conventional-differentiation chondrogenic media (ConvDiff) in MSC mono-cultures and AC:MSC co-cultures. We assessed gene expression of chondrogenic and hypertrophic markers using real-time RT-PCR and immunostaining. Alkaline-phosphatase activity (ALP) and calcium content of the pellets were quantified. We also measured VEGF and TNF-α secretion via ELISA. We showed PRP had higher chondrogenic potential (in mRNA and protein level) and hypertrophic-suppressive effects than Conv-Diff (mRNA level). Co-culturing reduced ALP while PRP increased calcium deposition. In all four groups, TNF-α was down-regulated compared to MSC controls, with co-cultures receiving ConvDiff media secreting the least. Meanwhile, the only group with increased VEGF secretion was PRP-mono-cultures. We observed synergistic effects for PRP and AC:MSC co-culture in enhancing chondrogenesis. Inclusion of AC reduced hypertrophic markers and angiogenic potential in PRP groups. We thus propose that combination of PRP and co-culture would favor chondrogenesis while alleviate but not totally eradicate undesired hypertrophic and pathologic responses. PMID:28900383

25th Space Simulation Conference. Environmental Testing: The Earth-Space Connection

NASA Technical Reports Server (NTRS)

Packard, Edward

2008-01-01

Topics covered include: Methods of Helium Injection and Removal for Heat Transfer Augmentation; The ESA Large Space Simulator Mechanical Ground Support Equipment for Spacecraft Testing; Temperature Stability and Control Requirements for Thermal Vacuum/Thermal Balance Testing of the Aquarius Radiometer; The Liquid Nitrogen System for Chamber A: A Change from Original Forced Flow Design to a Natural Flow (Thermo Siphon) System; Return to Mercury: A Comparison of Solar Simulation and Flight Data for the MESSENGER Spacecraft; Floating Pressure Conversion and Equipment Upgrades of Two 3.5kw, 20k, Helium Refrigerators; Affect of Air Leakage into a Thermal-Vacuum Chamber on Helium Refrigeration Heat Load; Special ISO Class 6 Cleanroom for the Lunar Reconnaissance Orbiter (LRO) Project; A State-of-the-Art Contamination Effects Research and Test Facility Martian Dust Simulator; Cleanroom Design Practices and Their Influence on Particle Counts; Extra Terrestrial Environmental Chamber Design; Contamination Sources Effects Analysis (CSEA) - A Tool to Balance Cost/Schedule While Managing Facility Availability; SES and Acoustics at GSFC; HST Super Lightweight Interchangeable Carrier (SLIC) Static Test; Virtual Shaker Testing: Simulation Technology Improves Vibration Test Performance; Estimating Shock Spectra: Extensions beyond GEVS; Structural Dynamic Analysis of a Spacecraft Multi-DOF Shaker Table; Direct Field Acoustic Testing; Manufacture of Cryoshroud Surfaces for Space Simulation Chambers; The New LOTIS Test Facility; Thermal Vacuum Control Systems Options for Test Facilities; Extremely High Vacuum Chamber for Low Outgassing Processing at NASA Goddard; Precision Cleaning - Path to Premier; The New Anechoic Shielded Chambers Designed for Space and Commercial Applications at LIT; Extraction of Thermal Performance Values from Samples in the Lunar Dust Adhesion Bell Jar; Thermal (Silicon Diode) Data Acquisition System; Aquarius's Instrument Science Data System (ISDS) Automated to Acquire, Process, Trend Data and Produce Radiometric System Assessment Reports; Exhaustive Thresholds and Resistance Checkpoints; Reconfigurable HIL Testing of Earth Satellites; FPGA Control System for the Automated Test of MicroShutters; Ongoing Capabilities and Developments of Re-Entry Plasma Ground Tests at EADS-ASTRIUM; Operationally Responsive Space Standard Bus Battery Thermal Balance Testing and Heat Dissipation Analysis; Galileo - The Serial-Production AIT Challenge; The Space Systems Environmental Test Facility Database (SSETFD), Website Development Status; Simulated Reentry Heating by Torching; Micro-Vibration Measurements on Thermally Loaded Multi-Layer Insulation Samples in Vacuum; High Temperature Life Testing of 80Ni-20Cr Wire in a Simulated Mars Atmosphere for the Sample Analysis at Mars (SAM) Instrument Suit Gas Processing System (GPS) Carbon Dioxide Scrubber; The Planning and Implementation of Test Facility Improvements; and Development of a Silicon Carbide Molecular Beam Nozzle for Simulation Planetary Flybys and Low-Earth Orbit.

Mesenchymal Stem Cells – Sources and Clinical Applications

PubMed Central

Klingemann, Hans; Matzilevich, David; Marchand, James

2008-01-01

Summary Although mesenchymal stem cells (MSC) from different tissue sources share many characteristics and generally fulfill accepted criteria for MSC (plastic adherence, certain surface marker expression, and ability to differentiate into mesenchymal tissues), we are increasingly learning that they can be distinguished at the level of cytokine production and gene expression profiles. Their ability to differentiate into different tissues including endodermal and ectodermal lineages, also varies according to tissue origin. Importantly, MSC from fetal sources can undergo more cell divisions before they reach senescence than MSC from adult tissue such as bone marrow or adipose tissue. As we learn more about the differentiation and plasticity of MSC from different sources, health care providers in the future will use them tailored to different medical indications. PMID:21512642

NSLS II Vacuum System

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ferreira, M.; Doom, L.; Hseuh, H.

2009-09-13

National Synchrotron Light Source II, being constructed at Brookhaven, is a 3-GeV, 500 mA, 3rd generation synchrotron radiation facility with ultra low emittance electron beams. The storage ring vacuum system has a circumference of 792 m and consists of over 250 vacuum chambers with a simulated average operating pressure of less than 1 x 10{sup -9} mbar. A summary of the update design of the vacuum system including girder supports of the chambers, gauges, vacuum pumps, bellows, beam position monitors and simulation of the average pressure will be shown. A brief description of the techniques and procedures for cleaning andmore » mounting the chambers are given.« less

Dynamic of distribution of human bone marrow-derived mesenchymal stem cells after transplantation into adult unconditioned mice.

PubMed

Allers, Carolina; Sierralta, Walter D; Neubauer, Sonia; Rivera, Francisco; Minguell, José J; Conget, Paulette A

2004-08-27

The use of mesenchymal stem cells (MSC) for cell therapy relies on their capacity to engraft and survive long-term in the appropriate target tissue(s). Animal models have demonstrated that the syngeneic or xenogeneic transplantation of MSC results in donor engraftment into the bone marrow and other tissues of conditioned recipients. However, there are no reliable data showing the fate of human MSC infused into conditioned or unconditioned adult recipients. In the present study, the authors investigated, by using imaging, polymerase chain reaction (PCR), and in situ hybridization, the biodistribution of human bone marrow-derived MSC after intravenous infusion into unconditioned adult nude mice. As assessed by imaging (gamma camera), PCR, and in situ hybridization analysis, the authors' results demonstrate the presence of human MSC in bone marrow, spleen, and mesenchymal tissues of recipient mice. These results suggest that human MSC transplantation into unconditioned recipients represents an option for providing cellular therapy and avoids the complications associated with drugs or radiation conditioning.

Mesenchymal stem cell mechanobiology and emerging experimental platforms

PubMed Central

MacQueen, Luke; Sun, Yu; Simmons, Craig A.

2013-01-01

Experimental control over progenitor cell lineage specification can be achieved by modulating properties of the cell's microenvironment. These include physical properties of the cell adhesion substrate, such as rigidity, topography and deformation owing to dynamic mechanical forces. Multipotent mesenchymal stem cells (MSCs) generate contractile forces to sense and remodel their extracellular microenvironments and thereby obtain information that directs broad aspects of MSC function, including lineage specification. Various physical factors are important regulators of MSC function, but improved understanding of MSC mechanobiology requires novel experimental platforms. Engineers are bridging this gap by developing tools to control mechanical factors with improved precision and throughput, thereby enabling biological investigation of mechanics-driven MSC function. In this review, we introduce MSC mechanobiology and review emerging cell culture platforms that enable new insights into mechanobiological control of MSCs. Our main goals are to provide engineers and microtechnology developers with an up-to-date description of MSC mechanobiology that is relevant to the design of experimental platforms and to introduce biologists to these emerging platforms. PMID:23635493

A microbial "bloom" at the onset of the Messinian Salinity Crisis in the Piedmont Basin (NW Italy)

NASA Astrophysics Data System (ADS)

Natalicchio, Marcello; Birgel, Daniel; Dela Pierre, Francesco; Lozar, Francesca; Liu, Xiaolei; Hinrichs, Kai-Uwe; Peckmann, Jörn

2015-04-01

The Messinian Salinity Crisis (MSC), a severe ecological crisis that occurred in the Mediterranean Basin about 6 myr ago, had drastic consequences for both freshwater and marine ecosystems (Roveri et al., 2014). The response of prokaryotes to the changing conditions at the MSC onset is virtually unknown. In a lipid biomarker study of sediments straddling the MSC onset from the Pollenzo section (NW Italy), we aim to evaluate the response of microbial communities at the transition from normal marine to extreme conditions. In this section, the advent of the MSC does not coincide with the deposition of gypsum; instead shales and intercalated carbonate-rich beds deposited. These deposits are considered as the deep water counterparts of gypsum layers that formed in the shallower parts of the basin (Dela Pierre et al., 2012). In both pre-MSC and MSC deposits, the molecular fossil inventory is sourced from all three domains of life and is mainly represented by isoprenoidal alcohols, fatty acids, sterols, long chain n-alkanes and n-alcohols. However, after the MSC onset, a sharp increase of the long chains n-alkanes, n-alcohols and fatty acids occurs, indicating a significant increase of terrigenous organic matter, most likely sourced by enhanced riverine runoff. Remarkably, this coincides with an increase of sterols (sitosterol and dinosterol), that are typically interpreted as markers of phytoplankton. The same strata contain filamentous fossils, which have been interpreted as remains of sulfide-oxidizing bacteria (cf., Dela Pierre et al., 2012). The basal MSC deposits are also typified by an increase of isoprenoidal alcohols, including glycerol dibiphytanyl glycerol tetraethers (GDGTs) and diphytanyl glycerol diethers (DGD). Caldarchaeol and crenarchaeol are the overall most abundant GDGTs. Their almost equal distribution in pre-MSC deposits suggests that they derived from planktic Thaumarchaeota, which are abundant picoplanktonic organisms in modern oceans. In contrast, caldarchaeol predominates over crenarchaeol in the MSC deposits, indicating a change towards harsh environmental conditions. A prominent spread of δ13C values between caldarchaeol- and crenarchaeol-derived biphytanes (Δδ13C: 9) in the MSC deposits agrees with a profound modification of the archaeal community structure. This is further confirmed by the sharp increase of the DGD archaeol and the appearance of the DGD extended archaeol. The latter is only sourced by halophilic archaea, confirming an increase of seawater salinity after the MSC onset. In conclusion, this study reveals that lipid biomarkers are excellent recorders of the MSC onset. Moreover, they help to reconstruct the Messinian microbial ecosystems in the course of changing environmental conditions. References Dela Pierre, F., et al., 2012. Palaeogeography, Palaeoclimatology, Palaeoecology 344/345, 78-93. Roveri et al., 2014. Marine Geology 352, 25-58.

KA-111, Phase C, M-1 Propellant Tests: Deflagration in Partial Confinement.

DTIC Science & Technology

1991-07-01

DNA Test Director and Mr. R. !. Flory, Washington Research Center, was Program Coordinator. The DDESB, NDCS , and SSO Technical Monitors for Phase C...to simulate the chamber and access tunnel proportions of the Shallow Underground Tunnel /Chamber Explosion Test conducted at China Lake, CA, in 1988...The chamber and access tunnel at China Lake had the following dimensions (volume, cross-sectional area and length): Chamber: V. - 331.2 m 3 Tunnel : Vt

A novel approach to predict the stability limits of combustion chambers with large eddy simulation

NASA Astrophysics Data System (ADS)

Pritz, B.; Magagnato, F.; Gabi, M.

2010-06-01

Lean premixed combustion, which allows for reducing the production of thermal NOx, is prone to combustion instabilities. There is an extensive research to develop a reduced physical model, which allows — without time-consuming measurements — to calculate the resonance characteristics of a combustion system consisting of Helmholtz resonator type components (burner plenum, combustion chamber). For the formulation of this model numerical investigations by means of compressible Large Eddy Simulation (LES) were carried out. In these investigations the flow in the combustion chamber is isotherm, non-reacting and excited with a sinusoidal mass flow rate. Firstly a combustion chamber as a single resonator subsequently a coupled system of a burner plenum and a combustion chamber were investigated. In this paper the results of additional investigations of the single resonator are presented. The flow in the combustion chamber was investigated without excitation at the inlet. It was detected, that the mass flow rate at the outlet cross section is pulsating once the flow in the chamber is turbulent. The fast Fourier transform of the signal showed that the dominant mode is at the resonance frequency of the combustion chamber. This result sheds light on a very important source of self-excited combustion instabilities. Furthermore the LES can provide not only the damping ratio for the analytical model but the eigenfrequency of the resonator also.

Microgrid Design Toolkit (MDT) Technical Documentation and Component Summaries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Arguello, Bryan; Gearhart, Jared Lee; Jones, Katherine A.

2015-09-01

The Microgrid Design Toolkit (MDT) is a decision support software tool for microgrid designers to use during the microgrid design process. The models that support the two main capabilities in MDT are described. The first capability, the Microgrid Sizing Capability (MSC), is used to determine the size and composition of a new microgrid in the early stages of the design process. MSC is a mixed-integer linear program that is focused on developing a microgrid that is economically viable when connected to the grid. The second capability is focused on refining a microgrid design for operation in islanded mode. This secondmore » capability relies on two models: the Technology Management Optimization (TMO) model and Performance Reliability Model (PRM). TMO uses a genetic algorithm to create and refine a collection of candidate microgrid designs. It uses PRM, a simulation based reliability model, to assess the performance of these designs. TMO produces a collection of microgrid designs that perform well with respect to one or more performance metrics.« less

Investigation of electron-loss and photon scattering correction factors for FAC-IR-300 ionization chamber

NASA Astrophysics Data System (ADS)

Mohammadi, S. M.; Tavakoli-Anbaran, H.; Zeinali, H. Z.

2017-02-01

The parallel-plate free-air ionization chamber termed FAC-IR-300 was designed at the Atomic Energy Organization of Iran, AEOI. This chamber is used for low and medium X-ray dosimetry on the primary standard level. In order to evaluate the air-kerma, some correction factors such as electron-loss correction factor (ke) and photon scattering correction factor (ksc) are needed. ke factor corrects the charge loss from the collecting volume and ksc factor corrects the scattering of photons into collecting volume. In this work ke and ksc were estimated by Monte Carlo simulation. These correction factors are calculated for mono-energy photon. As a result of the simulation data, the ke and ksc values for FAC-IR-300 ionization chamber are 1.0704 and 0.9982, respectively.

The effect of mesenchymal stem cell sheets on structural allograft healing of critical sized femoral defects in mice.

PubMed

Long, Teng; Zhu, Zhenan; Awad, Hani A; Schwarz, Edward M; Hilton, Matthew J; Dong, Yufeng

2014-03-01

Structural bone allografts are widely used in the clinic to treat critical sized bone defects, despite lacking the osteoinductive characteristics of live autografts. To address this, we generated revitalized structural allografts wrapped with mesenchymal stem/progenitor cell (MSC) sheets, which were produced by expanding primary syngenic bone marrow derived cells on temperature-responsive plates, as a tissue-engineered periosteum. In vitro assays demonstrated maintenance of the MSC phenotype in the sheets, suggesting that short-term culturing of MSC sheets is not detrimental. To test their efficacy in vivo, allografts wrapped with MSC sheets were transplanted into 4-mm murine femoral defects and compared to allografts with direct seeding of MSCs and allografts without cells. Evaluations consisted of X-ray plain radiography, 3D microCT, histology, and biomechanical testing at 4- and 6-weeks post-surgery. Our findings demonstrate that MSC sheets induce prolonged cartilage formation at the graft-host junction and enhanced bone callus formation, as well as graft-host osteointegration. Moreover, a large periosteal callus was observed spanning the allografts with MSC sheets, which partially mimics live autograft healing. Finally, biomechanical testing showed a significant increase in the structural and functional properties of MSC sheet grafted femurs. Taken together, MSC sheets exhibit enhanced osteogenicity during critical sized bone defect repair, demonstrating the feasibility of this tissue engineering solution for massive allograft healing. Copyright © 2013 Elsevier Ltd. All rights reserved.

Gastro-intestinal autoimmunity: preclinical experiences and successful therapy of fistulizing bowel diseases and gut Graft versus host disease by mesenchymal stromal cells.

PubMed

Voswinkel, Jan; Francois, Sabine; Gorin, Norbert-Claude; Chapel, Alain

2013-07-01

Mesenchymal stromal cells (MSC) are multipotent adult stem cells with the potential to regenerate tissue damage and inhibit inflammation and fibrosis in parallel. As they are non-immunogenic, MSC can be safely auto- and allotransplanted and consequently represent a therapeutic option for refractory connective tissue diseases and fistulizing colitis like Crohn's disease. Actually, there are more than 200 registered clinical trial sites for evaluating MSC therapy, 22 are on autoimmune diseases and 27 are actually recruiting bowel disease' patients. More than 1,500 patients with bowel diseases like Crohn's disease were treated in clinical trials by local as well as systemic MSC therapy. Phase I and II trials on fistula documented the feasibility and safety of MSC therapy, and a significant superiority compared to fibrin glue in fistulizing bowel diseases was demonstrated. Autologous as well as allogeneic use of Bone marrow as well as of adipose tissue-derived MSC are feasible. In refractory Graft versus host disease, especially in refractory gut Graft versus host diseases, encouraging results were reported using MSC. Systemic MSC therapy of refractory irradiation-induced colitis was safe and effective on pain, diarrhea, hemorrhage, inflammation and fistulization accompanied by modulation of the lymphocyte subsets toward an increase in T regulatory cells and a decrease in activated effector T cells. Mesenchymal stem cells represent a safe therapy for patients with refractory inflammatory bowel diseases.

Postnatal extra-embryonic tissues as a source of multiple cell types for regenerative medicine applications.

PubMed

Gubar, O S; Rodnichenko, A E; Vasyliev, R G; Zlatska, A V; Zubov, D O

2017-09-01

We aimed to isolate and characterize the cell types which could be obtained from postnatal extra-embryonic tissues. Fresh tissues (no more than 12 h after delivery) were used for enzymatic or explants methods of cell isolation. Obtained cultures were further maintained at 5% oxygen. At P3 cell phenotype was assessed by fluorescence-activated cell sorting, population doubling time was calculated and the multilineage differentiation assay was performed. We have isolated multiple cell types from postnatal tissues. Namely, placental mesenchymal stromal cells from placenta chorionic disc, chorionic membrane mesenchymal stromal cells (ChM-MSC) from free chorionic membrane, umbilical cord MSC (UC-MSC) from whole umbilical cord, human umbilical vein endothelial cells (HUVEC) from umbilical vein, amniotic epithelial cells (AEC) and amniotic MSC (AMSC) from amniotic membrane. All isolated cell types displayed high proliferation rate together with the typical MSC phenotype: CD73 + CD90 + CD105 + CD146 + CD166+CD34 - CD45 - HLA-DR - . HUVEC constitutively expressed key markers CD31 and CD309. Most MSC and AEC were capable of osteogenic and adipogenic differentiation. We have shown that a wide variety of cell types can be easily isolated from extra-embryonic tissues and expanded ex vivo for regenerative medicine applications. These cells possess typical MSC properties and can be considered an alternative for adult MSC obtained from bone marrow or fat, especially for allogeneic use.

The analysis on the relation between the compression method and the performance enhancement of MSC (Multi-Spectral Camera) image data

NASA Astrophysics Data System (ADS)

Yong, Sang-Soon; Ra, Sung-Woong

2007-10-01

Multi-Spectral Camera(MSC) is a main payload on the KOMPSAT-2 satellite to perform the earth remote sensing. The MSC instrument has one(1) channel for panchromatic imaging and four(4) channel for multi-spectral imaging covering the spectral range from 450nm to 900nm using TDI CCD Focal Plane Array (FPA). The instrument images the earth using a push-broom motion with a swath width of 15 km and a ground sample distance (GSD) of 1 m over the entire field of view (FOV) at altitude 685 Km. The instrument is designed to have an on-orbit operation duty cycle of 20% over the mission lifetime of 3 years with the functions of programmable gain/ offset and on-board image data compression/ storage. The compression method on KOMPSAT-2 MSC was selected and used to match EOS input rate and PDTS output data rate on MSC image data chain. At once the MSC performance was carefully handled to minimize any degradation so that it was analyzed and restored in KGS(KOMPSAT Ground Station) during LEOP and Cal./Val.(Calibration and Validation) phase. In this paper, on-orbit image data chain in MSC and image data processing on KGS including general MSC description is briefly described. The influences on image performance between on-board compression algorithms and between performance restoration methods in ground station are analyzed, and the relation between both methods is to be analyzed and discussed.

PVA-chitosan composite hydrogel versus alginate beads as a potential mesenchymal stem cell carrier for the treatment of focal cartilage defects.

PubMed

Dashtdar, Havva; Murali, Malliga Raman; Abbas, Azlina Amir; Suhaeb, Abdulrazzaq Mahmod; Selvaratnam, Lakshmi; Tay, Liang Xin; Kamarul, Tunku

2015-05-01

To investigate whether mesenchymal stem cells (MSCs) seeded in novel polyvinyl alcohol (PVA)-chitosan composite hydrogel can provide comparable or even further improve cartilage repair outcomes as compared to previously established alginate-transplanted models. Medial femoral condyle defect was created in both knees of twenty-four mature New Zealand white rabbits, and the animals were divided into four groups containing six animals each. After 3 weeks, the right knees were transplanted with PVA-chitosan-MSC, PVA-chitosan scaffold alone, alginate-MSC construct or alginate alone. The left knee was kept as untreated control. Animals were killed at the end of 6 months after transplantation, and the cartilage repair was assessed through Brittberg morphological score, histological grading by O'Driscoll score and quantitative glycosaminoglycan analysis. Morphological and histological analyses showed significant (p < 0.05) tissue repair when treated with PVA-chitosan-MSC or alginate MSC as compared to the scaffold only and untreated control. In addition, safranin O staining and the glycosaminoglycan (GAG) content were significantly higher (p < 0.05) in MSC treatment groups than in scaffold-only or untreated control group. No significant difference was observed between the PVA-chitosan-MSC- and alginate-MSC-treated groups. PVA-chitosan hydrogel seeded with mesenchymal stem cells provides comparable treatment outcomes to that of previously established alginate-MSC construct implantation. This study supports the potential use of PVA-chitosan hydrogel seeded with MSCs for clinical use in cartilage repair such as traumatic injuries.

Effects of Exendin-4 on bone marrow mesenchymal stem cell proliferation, migration and apoptosis in vitro

PubMed Central

Zhou, Hao; Li, Dandan; Shi, Chen; Xin, Ting; Yang, Junjie; Zhou, Ying; Hu, Shunyin; Tian, Feng; Wang, Jing; Chen, Yundai

2015-01-01

Mesenchymal stem cells (MSC) are regarded as an attractive source of therapeutic stem cells for myocardial infarction. However, their limited self-renewal capacity, low migration capacity and poor viability after transplantation hamper the clinical use of MSC; thus, a strategy to enhance the biological functions of MSC is required. Exendin-4 (Ex-4), a glucagon-like peptide-1 receptor agonist, exerts cell-protective effects on many types of cells. However, little information is available regarding the influence of Ex-4 on MSC. In our study, MSC were isolated from bone marrow and cultured in vitro. After treatment with Ex-4, MSC displayed a higher proliferative capacity, increased C-X-C motif receptor 4 (CXCR4) expression and an enhanced migration response. Moreover, in H2O2-induced apoptosis, Ex-4 preserved mitochondrial function through scavenging ROS and balancing the expression of anti- and pro-apoptotic proteins, leading to the inhibition of the mitochondria-dependent cell death pathways and increased cell survival. Moreover, higher phospho-Akt (p-Akt) expression was observed after Ex-4 intervention. However, blockade of the PI3K/Akt pathway with inhibitors suppressed the above cytoprotective effects of Ex-4, suggesting that the PI3K/Akt pathway is partly responsible for Ex-4-mediated MSC growth, mobilization and survival. These findings provide an attractive method of maximizing the effectiveness of MSC-based therapies in clinical applications. PMID:26250571

Mechanosensitive channels of Escherichia coli: the MscL gene, protein, and activities

NASA Technical Reports Server (NTRS)

Sukharev, S. I.; Blount, P.; Martinac, B.; Kung, C.

1997-01-01

Although mechanosensory responses are ubiquitous and diverse, the molecular bases of mechanosensation in most cases remain mysterious MscL, a mechanosensitive channel of large conductance of Escherichia coli and its bacterial homologues are the first and currently only channel molecules shown to directly sense mechanical stretch of the membrane. In response to the tension conveyed via the lipid bilayer, MscL increases its open probability by several orders of magnitude. In the present review we describe the identification, cloning, and first sets of biophysical and structural data on this simplest mechanosensory molecule. We discovered a 2.5-ns mechanosensitive conductance in giant E. coli spheroplasts. Using chromatographies to enrich the target and patch clamp to assay the channel activity in liposome-reconstituted fractions, we identified the MscL protein and cloned the mscL gene. MscL comprises 136 amino acid residues (15 kDa), with two highly hydrophobic regions, and resides in the inner membrane of the bacterium. PhoA-fusion experiments indicate that the protein spans the membrane twice with both termini in the cytoplasm. Spectroscopic techniques show that it is highly helical. Expression of MscL tandems and covalent cross-linking suggest that the active channel complex is a homo-hexamer. We have identified several residues, which when deleted or substituted, affect channel kinetics or mechanosensitivity. Although unique when discovered, highly conserved MscL homologues in both gram-negative and gram-positive bacteria have been found, suggesting their ubiquitous importance among bacteria.

Recipient Glycemic Micro-environments Govern Therapeutic Effects of Mesenchymal Stem Cell Infusion on Osteopenia

PubMed Central

Sui, Bing-Dong; Hu, Cheng-Hu; Zheng, Chen-Xi; Shuai, Yi; He, Xiao-Ning; Gao, Ping-Ping; Zhao, Pan; Li, Meng; Zhang, Xin-Yi; He, Tao; Xuan, Kun; Jin, Yan

2017-01-01

Therapeutic effects of mesenchymal stem cell (MSC) infusion have been revealed in various human disorders, but impacts of diseased micro-environments are only beginning to be noticed. Donor diabetic hyperglycemia is reported to impair therapeutic efficacy of stem cells. However, whether recipient diabetic condition also affects MSC-mediated therapy is unknown. We and others have previously shown that MSC infusion could cure osteopenia, particularly in ovariectomized (OVX) mice. Here, we discovered impaired MSC therapeutic effects on osteopenia in recipient type 1 diabetes (T1D). Through intensive glycemic control by daily insulin treatments, therapeutic effects of MSCs on osteopenia were maintained. Interestingly, by only transiently restoration of recipient euglycemia using single insulin injection, MSC infusion could also rescue T1D-induced osteopenia. Conversely, under recipient hyperglycemia induced by glucose injection in OVX mice, MSC-mediated therapeutic effects on osteopenia were diminished. Mechanistically, recipient hyperglycemic micro-environments reduce anti-inflammatory capacity of MSCs in osteoporotic therapy through suppressing MSC interaction with T cells via the Adenosine monophosphate-activated protein kinase (AMPK) pathway. We further revealed in diabetic micro-environments, double infusion of MSCs ameliorated osteopenia by anti-inflammation, attributed to the first transplanted MSCs which normalized the recipient glucose homeostasis. Collectively, our findings uncover a previously unrecognized role of recipient glycemic conditions controlling MSC-mediated therapy, and unravel that fulfillment of potent therapeutic effects of MSCs requires tight control of recipient micro-environments. PMID:28435461

Creating the Deep Space Environment for Testing the James Webb Space Telescope (JWST) at NASA Johnson Space Center's Chamber A

NASA Technical Reports Server (NTRS)

Homan, Jonathan L.; Cerimele, Mary P.; Montz, Michael E.; Bachtel, Russell; Speed, John; O'Rear, Patrick

2013-01-01

Chamber A is the largest thermal vacuum chamber at the Johnson Space Center and is one of the largest space environment chambers in the world. The chamber is 19.8 m (65 ft) in diameter and 36.6 m (120 ft) tall and is equipped with cryogenic liquid nitrogen panels (shrouds) and gaseous helium shrouds to create a simulated space environment. It was originally designed and built in the mid 1960 s to test the Apollo Command and Service Module and several manned tests were conducted on that spacecraft, contributing to the success of the program. The chamber has been used since that time to test spacecraft active thermal control systems, Shuttle DTO, DOD, and ESA hardware in simulated Low Earth Orbit (LEO) conditions. NASA is now moving from LEO towards exploration of locations with environments approaching those of deep space. Therefore, Chamber A has undergone major modifications to enable it to simulate these deeper space environments. Environmental requirements were driven, and modifications were funded by the James Webb Space Telescope program, and this telescope which will orbit Solar/Earth L2, will be the first test article to benefit from the chamber s new capabilities. To accommodate JWST, the Chamber A high vacuum system has been modernized, additional LN2 shrouds have been installed, the liquid nitrogen system has been modified to remove dependency on electrical power and increase its reliability, a new helium shroud/refrigeration system has been installed to create a colder more stable and uniform heat sink, and the controls have been updated to increase the level of automation and improve operator interfaces. Testing of these major modifications was conducted in August of 2012 and this initial test was very successful, with all major systems exceeding their performance requirements. This paper will outline the changes in overall environmental requirements, discuss the technical design data that was used in the decisions leading to the extensive modifications, and describe the new capabilities of the chamber.

Creating the Deep Space Environment for Testing the James Webb Space Telescope at NASA Johnson Space Center's Chamber A

NASA Technical Reports Server (NTRS)

Homan, Jonathan L.; Cerimele, Mary P.; Montz, Michael E.; Bachtel, Russell; Speed, John; O'Rear, Patrick

2013-01-01

Chamber A is the largest thermal vacuum chamber at the Johnson Space Center and is one of the largest space environment chambers in the world. The chamber is 19.8 m (65 ft.) in diameter and 36.6 m (120 ft.) tall and is equipped with cryogenic liquid nitrogen panels (shrouds) and gaseous helium shrouds to create a simulated space environment. It was originally designed and built in the mid 1960 s to test the Apollo Command and Service Module and several manned tests were conducted on that spacecraft, contributing to the success of the program. The chamber has been used since that time to test spacecraft active thermal control systems, Shuttle DTO, DOD, and ESA hardware in simulated Low Earth Orbit (LEO) conditions. NASA is now moving from LEO towards exploration of locations with environments approaching those of deep space. Therefore, Chamber A has undergone major modifications to enable it to simulate these deeper space environments. Environmental requirements were driven, and modifications were funded by the James Webb Space Telescope program, and this telescope, which will orbit Solar/Earth L2, will be the first test article to benefit from the chamber s new capabilities. To accommodate JWST, the Chamber A high vacuum system has been modernized, additional LN2 shrouds have been installed, the liquid nitrogen system has been modified to minimize dependency on electrical power and increase its reliability, a new helium shroud/refrigeration system has been installed to create a colder more stable and uniform heat sink, and the controls have been updated to increase the level of automation and improve operator interfaces. Testing of these major modifications was conducted in August of 2012 and this initial test was very successful, with all major systems exceeding their performance requirements. This paper will outline the changes in overall environmental requirements, discuss the technical design data that was used in the decisions leading to the extensive modifications, and describe the new capabilities of the chamber.

Creating the Deep Space Environment for Testing the James Webb Space Telescope at the Johnson Space Center's Chamber A

NASA Technical Reports Server (NTRS)

Homan, Jonathan L.; Cerimele, Mary P.; Montz, Michael E.

2012-01-01

Chamber A is the largest thermal vacuum chamber at the Johnson Space Center and is one of the largest space environment chambers in the world. The chamber is 19.8 m (65 ft) in diameter and 36.6 m (120 ft) tall and is equipped with cryogenic liquid nitrogen panels (shrouds) and gaseous helium shrouds to create a simulated space environment. It was originally designed and built in the mid 1960's to test the Apollo Command and Service Module and several manned tests were conducted on that spacecraft, contributing to the success of the program. The chamber has been used since that time to test spacecraft active thermal control systems, Shuttle DTO, DOD, and ESA hardware in simulated Low Earth Orbit (LEO) conditions. NASA is now moving from LEO towards exploration of locations with environments approaching those of deep space. Therefore, Chamber A has undergone major modifications to enable it to simulate these deeper space environments. Environmental requirements were driven, and the modifications were funded, by the James Webb Space Telescope program, and this telescope which will orbit Solar/Earth L2, will be the first test article to benefit from the chamber s new capabilities. To accommodate JWST, the Chamber A high vacuum system has been modernized, additional LN2 shrouds have been installed, the liquid nitrogen system has been modified to remove dependency on electrical power and increase its reliability, a new helium shroud/refrigeration system has been installed to create a colder more stable and uniform heat sink and, the controls have been updated to increase the level of automation and improve operator interfaces. Testing of these major modifications was conducted in August 2012 and this initial test was very successful, with all major systems exceeding their performance requirements. This paper will outline the changes in the overall environmental requirements, discuss the technical design data that was used in the decisions leading to the extensive modifications, and describe the new capabilities of the chamber.

Influence of ion chamber response on in-air profile measurements in megavoltage photon beams.

PubMed

Tonkopi, E; McEwen, M R; Walters, B R B; Kawrakow, I

2005-09-01

This article presents an investigation of the influence of the ion chamber response, including buildup caps, on the measurement of in-air off-axis ratio (OAR) profiles in megavoltage photon beams using Monte Carlo simulations with the EGSnrc system. Two new techniques for the calculation of OAR profiles are presented. Results of the Monte Carlo simulations are compared to measurements performed in 6, 10 and 25 MV photon beams produced by an Elekta Precise linac and shown to agree within the experimental and simulation uncertainties. Comparisons with calculated in-air kerma profiles demonstrate that using a plastic mini phantom gives more accurate air-kerma measurements than using high-Z material buildup caps and that the variation of chamber response with distance from the central axis must be taken into account.

Geant4 simulation of ion chambers response to 60Co spectrum of LNMRI/IRD Shepherd 81-14D Radiator

NASA Astrophysics Data System (ADS)

Queiroz Filho, P. P.; Da Silva, C. N. M.

2018-03-01

The National Ionizing Radiation Metrology Laboratory of the Radioprotection and Dosimetry Institute (LNMRI / IRD) has recently acquired a Shepherd 81-14D Radiator. In this work we simulate, using Geant4, the behavior with the inverse square law radiation for 3 models of PTW spherical chambers used in radioprotection, a relevant information to planning the measurements. We did the corrections for the attenuation and scattering in the air for each distance, where we used the 60Co spectrum simulated previously.

Integrated Design and Analysis Tools for Reduced Weight, Affordable Fiber Steered Composites

DTIC Science & Technology

2004-09-15

110 3.3.5 FEA Package: MSC/PATRAN and MSC/ NASTRAN ...3.10 APPENDIX D: FIBER STEERING CONCEPTUAL DESIGN OF PRELIMINARY STUDIES USING MSC/ NASTRAN SOL 200...and Boundary Conditions ......................................................... 366 Figure 5.3.10 Nastran Analysis Results for Off-Axis Flaws

Mesenchymal Stem Cells Stabilize Atherosclerotic Vulnerable Plaque by Anti-Inflammatory Properties.

PubMed

Wang, Shuang-shuang; Hu, Si-wang; Zhang, Qing-hua; Xia, Ai-xiang; Jiang, Zhi-xin; Chen, Xiao-min

2015-01-01

Formation and progression of atherosclerotic vulnerable plaque (VP) is the primary cause of many cardio-cerebrovascular diseases such as acute coronary syndrome and stroke. It has been reported that bone marrow mesenchymal stem cells (MSC) exhibit protective effects against many kinds of diseases including myocardial infarction. Here, we examined the effects of intravenous MSC infusion on a VP model and provide novel evidence of its influence as a therapy in this animal disease model. Thirty healthy male New Zealand white rabbits were randomly divided into a MSC, VP or stable plaque (SP) group (n = 10/group) and received high fat diet and cold-induced common carotid artery intimal injury with liquid nitrogen to form atherosclerotic plaques. Serum hs-CRP, TNF-α, IL-6 and IL-10 levels were measured by ELISA at 1, 2, 3, 7, 14, 21 and 28 days after MSC transplantation. The animals were sacrificed at 4 weeks after MSC transplantation. Lesions in the right common carotid were observed using H&E and Masson staining, and the fibrous cap/lipid core ratio of atherosclerotic plaques were calculated. The expression of nuclear factor κB (NF-κB) and matrix metalloproteinase 1, 2, 9 (MMP-1,2,9) in the plaque were detected using immunohistochemistry, and apoptotic cells in the plaques were detected by TUNEL. In addition, the level of TNF-α stimulated gene/protein 6 (TSG-6) mRNA and protein were measured by quantitative Real-Time PCR and Western blotting, respectively. Two rabbits in the VP group died of lung infection and cerebral infarction respectively at 1 week after plaque injury by liquid nitrogen. Both H&E and Masson staining revealed that the plaques from the SP and MSC groups had more stable morphological structure and a larger fibrous cap/lipid core ratio than the VP group. Serum hs-CRP, TNF-α and IL-6 were significantly down-regulated, whereas IL-10 was significantly up-regulated in the MSC group compared with the VP group. .Immunohistochemistry analysis revealed that NF-κB and MMP expression was reduced in the MSC and SP groups compared to the VP group. Cell apoptosis decreased significantly in both the MSC and SP groups in comparison to the VP group. TSG-6 mRNA and protein expression were higher in the plaques of the MSC group compared to the VP and SP groups. Our study results suggest that MSC transplantation can effectively stabilize vulnerable plaques in atherosclerotic rabbits. This may potentially offer a new clinical application of MSC in atherosclerosis.

Astronaut Gene Cernan poses in front of Gemini Mission Simulator

NASA Image and Video Library

1966-08-09

S66-32698 (17 June 1966) --- Astronaut Eugene A. Cernan discusses his Gemini-9A extravehicular activity before a gathering of news media representatives in the MSC auditorium. In the background is an Astronaut Maneuvering Unit (AMU) mock-up mounted in a mock-up of a Gemini spacecraft adapter equipment section. Astronauts Cernan and Thomas P. Stafford completed their three-day mission in space on June 6, 1966. Photo credit: NASA

Simbol-X Background Minimization: Mirror Spacecraft Passive Shielding Trade-off Study

NASA Astrophysics Data System (ADS)

Fioretti, V.; Malaguti, G.; Bulgarelli, A.; Palumbo, G. G. C.; Ferri, A.; Attinà, P.

2009-05-01

The present work shows a quantitative trade-off analysis of the Simbol-X Mirror Spacecraft (MSC) passive shielding, in the phase space of the various parameters: mass budget, dimension, geometry and composition. A simplified physical (and geometrical) model of the sky screen, implemented by means of a GEANT4 simulation, has been developed to perform a performance-driven mass optimization and evaluate the residual background level on Simbol-X focal plane.

Assessing multiscale complexity of short heart rate variability series through a model-based linear approach

NASA Astrophysics Data System (ADS)

Porta, Alberto; Bari, Vlasta; Ranuzzi, Giovanni; De Maria, Beatrice; Baselli, Giuseppe

2017-09-01

We propose a multiscale complexity (MSC) method assessing irregularity in assigned frequency bands and being appropriate for analyzing the short time series. It is grounded on the identification of the coefficients of an autoregressive model, on the computation of the mean position of the poles generating the components of the power spectral density in an assigned frequency band, and on the assessment of its distance from the unit circle in the complex plane. The MSC method was tested on simulations and applied to the short heart period (HP) variability series recorded during graded head-up tilt in 17 subjects (age from 21 to 54 years, median = 28 years, 7 females) and during paced breathing protocols in 19 subjects (age from 27 to 35 years, median = 31 years, 11 females) to assess the contribution of time scales typical of the cardiac autonomic control, namely in low frequency (LF, from 0.04 to 0.15 Hz) and high frequency (HF, from 0.15 to 0.5 Hz) bands to the complexity of the cardiac regulation. The proposed MSC technique was compared to a traditional model-free multiscale method grounded on information theory, i.e., multiscale entropy (MSE). The approach suggests that the reduction of HP variability complexity observed during graded head-up tilt is due to a regularization of the HP fluctuations in LF band via a possible intervention of sympathetic control and the decrement of HP variability complexity observed during slow breathing is the result of the regularization of the HP variations in both LF and HF bands, thus implying the action of physiological mechanisms working at time scales even different from that of respiration. MSE did not distinguish experimental conditions at time scales larger than 1. Over a short time series MSC allows a more insightful association between cardiac control complexity and physiological mechanisms modulating cardiac rhythm compared to a more traditional tool such as MSE.

14CO2 analysis of soil gas: Evaluation of sample size limits and sampling devices

NASA Astrophysics Data System (ADS)

Wotte, Anja; Wischhöfer, Philipp; Wacker, Lukas; Rethemeyer, Janet

2017-12-01

Radiocarbon (14C) analysis of CO2 respired from soils or sediments is a valuable tool to identify different carbon sources. The collection and processing of the CO2, however, is challenging and prone to contamination. We thus continuously improve our handling procedures and present a refined method for the collection of even small amounts of CO2 in molecular sieve cartridges (MSCs) for accelerator mass spectrometry 14C analysis. Using a modified vacuum rig and an improved desorption procedure, we were able to increase the CO2 recovery from the MSC (95%) as well as the sample throughput compared to our previous study. By processing series of different sample size, we show that our MSCs can be used for CO2 samples of as small as 50 μg C. The contamination by exogenous carbon determined in these laboratory tests, was less than 2.0 μg C from fossil and less than 3.0 μg C from modern sources. Additionally, we tested two sampling devices for the collection of CO2 samples released from soils or sediments, including a respiration chamber and a depth sampler, which are connected to the MSC. We obtained a very promising, low process blank for the entire CO2 sampling and purification procedure of ∼0.004 F14C (equal to 44,000 yrs BP) and ∼0.003 F14C (equal to 47,000 yrs BP). In contrast to previous studies, we observed no isotopic fractionation towards lighter δ13C values during the passive sampling with the depth samplers.

Multiphase flow modeling in centrifugal partition chromatography.

PubMed

Adelmann, S; Schwienheer, C; Schembecker, G

2011-09-09

The separation efficiency in Centrifugal Partition Chromatography (CPC) depends on selection of a suitable biphasic solvent system (distribution ratio, selectivity factor, sample solubility) and is influenced by hydrodynamics in the chambers. Especially the stationary phase retention, the interfacial area for mass transfer and the flow pattern (backmixing) are important parameters. Their relationship with physical properties, operating parameters and chamber geometry is not completely understood and predictions are hardly possible. Experimental flow visualization is expensive and two-dimensional only. Therefore we simulated the flow pattern using a volume-of-fluid (VOF) method, which was implemented in OpenFOAM®. For the three-dimensional simulation of a rotating FCPC®-chamber, gravitational centrifugal and Coriolis forces were added to the conservation equation. For experimental validation the flow pattern of different solvent systems was visualized with an optical measurement system. The amount of mobile phase in a chamber was calculated from gray scale values of videos recorded by an image processing routine in ImageJ®. To visualize the flow of the stationary phase polyethylene particles were used to perform a qualitative particle image velocimetry (PIV) analysis. We found a good agreement between flow patterns and velocity profiles of experiments and simulations. By using the model we found that increasing the chamber depth leads to higher specific interfacial area. Additionally a circular flow in the stationary phase was identified that lowers the interfacial area because it pushes the jet of mobile phase to the chamber wall. The Coriolis force alone gives the impulse for this behavior. As a result the model is easier to handle than experiments and allows 3D prediction of hydrodynamics in the chamber. Additionally it can be used for optimizing geometry and operating parameters for given physical properties of solvent systems. Copyright © 2011 Elsevier B.V. All rights reserved.

48 CFR 247.573-1 - Ocean transportation incidental to a contract for supplies, services, or construction.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Business Management Directorate, MSC; or (ii) The Commander, Military Surface Deployment and Distribution... Commander, MSC, through the Contracts and Business Management Directorate, MSC; or (B) The Commander... MANAGEMENT TRANSPORTATION Ocean Transportation by U.S.-Flag Vessels 247.573-1 Ocean transportation incidental...

MISSION CONTROL CENTER (MCC) VIEW - CONCLUSION APOLLO 11 CELEBRATION - MSC

NASA Image and Video Library

1969-07-24

S69-40024 (24 July 1969) --- NASA and Manned Spacecraft Center (MSC) officials join in with the flight controllers, in the Mission Operations Control Room (MOCR) in the Mission Control Center (MCC), in celebrating the successful conclusion of the Apollo 11 lunar landing mission. Identifiable in the picture, starting in foreground, are Dr. Robert R. Gilruth, MSC Director; George M. Low, Manager, Apollo Spacecraft Program, MSC; Dr. Christopher C. Kraft Jr., MSC Director of Flight Operation; U.S. Air Force Lt. Gen. Samuel C. Phillips (with glasses, looking downward), Apollo Program Director, Office of Manned Space Flight, NASA Headquarters; and Dr. George E. Mueller (with glasses, looking toward left), Associate Administrator, Office of Manned Space Flight, NASA Headquarters. Former astronaut John H. Glenn Jr. is standing behind Mr. Low.

Mesenchymal stem cells display hepato-protective activity in lymphoma bearing xenografts.

PubMed

Secchiero, Paola; Corallini, Federica; Zavan, Barbara; Tripodo, Claudio; Vindigni, Vincenzo; Zauli, Giorgio

2012-04-01

A disseminated model of non-Hodgkin's lymphoma with prevalent liver metastasis was generated by intraperitoneal (i.p.) injection of EBV(+) B lymphoblastoid SKW6.4 in nude-SCID mice. The survival of SKW6.4 xenografts (median survival = 27 days) was significantly improved when hyaluronan scaffolds embedded with mesenchimal stem cells (MSC) were implanted in the abdominal area 4 days after SKW6.4 injection (median survival = 39.5 days). Mice implanted with MSC showed a significant improvement of hepatic functionality in lymphoma xenografts, as demonstrated by measurement of serum ALT/AST levels. Co-culture of MSC with lymphoma cells enhanced the release of hepatocyte growth factor (HGF) by MSC. These data suggest that hyaluronan-embedded MSC exert anti-lymphoma activity by ameliorating hepatic functionality.

Marrow-derived mesenchymal stem cells: role in epithelial tumor cell determination.

PubMed

Fierro, Fernando A; Sierralta, Walter D; Epuñan, Maria J; Minguell, José J

2004-01-01

Marrow stroma represents an advantageous environment for development of micrometastatic cells. Within the cellular structure of marrow stroma, mesenchymal stem cells (MSC) have been postulated as an interacting target for disseminated cancer cells. The studies reported here were performed to gain more information on the interaction of the human breast cancer cell line MCF-7 with human bone marrow-derived MSC cells and to investigate whether this interaction affects tumor cell properties. The results showed that after co-culture with MSC, changes were detected in the morphology, proliferative capacity and aggregation pattern of MCF-7 cells, but these parameters were not affected after the co-culture of MSC cells with a non-tumorigenic breast epithelial cell line, MCF-10. Since the indirect culture of MCF-7 with MSC or its products also resulted in functional changes in the tumor cells, we evaluated whether these effects could be attributed to growth factors produced by MSC cells. It was found that VEGF and IL-6 mimic the effects produced by MSC or its products on the proliferation and aggregation properties of MCF-7, cells, respectively. Thus, it seems that after entry of disseminated tumor cells into the marrow space, their proliferative and morphogenetic organization patterns are modified after interaction with distinct stromal cells and/or with specific signals from the marrow microenvironment.

Finding and tracing human MSC in 3D microenvironments with the photoconvertible protein Dendra2

NASA Astrophysics Data System (ADS)

Caires, Hugo R.; Gomez-Lazaro, Maria; Oliveira, Carla M.; Gomes, David; Mateus, Denisa D.; Oliveira, Carla; Barrias, Cristina C.; Barbosa, Mário A.; Almeida, Catarina R.

2015-05-01

Mesenchymal Stem/Stromal Cells (MSC) are a promising cell type for cell-based therapies - from tissue regeneration to treatment of autoimmune diseases - due to their capacity to migrate to damaged tissues, to differentiate in different lineages and to their immunomodulatory and paracrine properties. Here, a simple and reliable imaging technique was developed to study MSC dynamical behavior in natural and bioengineered 3D matrices. Human MSC were transfected to express a fluorescent photoswitchable protein, Dendra2, which was used to highlight and follow the same group of cells for more than seven days, even if removed from the microscope to the incubator. This strategy provided reliable tracking in 3D microenvironments with different properties, including the hydrogels Matrigel and alginate as well as chitosan porous scaffolds. Comparison of cells mobility within matrices with tuned physicochemical properties revealed that MSC embedded in Matrigel migrated 64% more with 5.2 mg protein/mL than with 9.6 mg/mL and that MSC embedded in RGD-alginate migrated 51% faster with 1% polymer concentration than in 2% RGD-alginate. This platform thus provides a straightforward approach to characterize MSC dynamics in 3D and has applications in the field of stem cell biology and for the development of biomaterials for tissue regeneration.

Morphological and Functional Attenuation of Degeneration of Peripheral Neurons by Mesenchymal Stem Cell-Conditioned Medium in Spinocerebellar Ataxia Type 1-Knock-in Mice.

PubMed

Suto, Nana; Mieda, Tokue; Iizuka, Akira; Nakamura, Kazuhiro; Hirai, Hirokazu

2016-08-01

Spinocerebellar ataxia type 1 (SCA1) is caused by the ataxin-1 protein (ATXN1) with an abnormally expanded polyglutamine tract and is characterized by progressive neurodegeneration. We previously showed that intrathecal injection of mesenchymal stem cells (MSCs) during the nonsymptomatic stage mitigates the degeneration of the peripheral nervous system (PNS) neurons in SCA1-knock-in (SCA1-KI) mice. We tested in this study whether the therapeutic effects of MSCs in SCA1-KI mice could be reproduced with MSC-releasing factor(s). To test the effects of MSC-releasing factor(s), we used MSC-conditioned medium (MSC-CM). MSC-CM was intrathecally and/or intravenously injected into young SCA1-KI mice, and the therapeutic effects were assessed in the PNS at later ages using immunostaining, electrophysiology, and behavioral tests. MSC-CM attenuated the degeneration of axons and myelin of spinal motor neurons. Consequently, the injected SCA1-KI mice exhibited smaller reductions in nerve conduction velocity in spinal motor neurons and reduced motor incoordination than the untreated mice. These results suggest that factors released from MSC mitigate the morphological and functional abnormalities in the PNS that are observed in SCA1-KI mice in a paracrine manner. © 2016 John Wiley & Sons Ltd.

Antitumor Activity of a Mesenchymal Stem Cell Line Stably Secreting a Tumor-Targeted TNF-Related Apoptosis-Inducing Ligand Fusion Protein

PubMed Central

Marini, Irene; Siegemund, Martin; Hutt, Meike; Kontermann, Roland E.; Pfizenmaier, Klaus

2017-01-01

Mesenchymal stem cells (MSCs) are currently exploited as gene delivery systems for transient in situ expression of cancer therapeutics. As an alternative to the prevailing viral expression, we here describe a murine MSC line stably expressing a therapeutic protein for up to 42 passages, yet fully maintaining MSC features. Because of superior antitumoral activity of hexavalent TNF-related apoptosis-inducing ligand (TRAIL) formats and the advantage of a tumor-targeted action, we choose expression of a dimeric EGFR-specific diabody single-chain TRAIL (Db-scTRAIL) as a model. The bioactivity of Db-scTRAIL produced from an isolated clone (MSC.TRAIL) was revealed from cell death induction in Colo205 cells treated with either culture supernatants from or cocultured with MSC.TRAIL. In vivo, therapeutic activity of MSC.TRAIL was shown upon peritumoral injection in a Colo205 xenograft tumor model. Best antitumor activity in vitro and in vivo was observed upon combined treatment of MSC.TRAIL with bortezomib. Importantly, in vivo combination treatment did not cause apparent hepatotoxicity, weight loss, or behavioral changes. The development of well characterized stocks of stable drug-producing human MSC lines has the potential to establish standardized protocols of cell-based therapy broadly applicable in cancer treatment. PMID:28553285

A fat option for the pig: Hepatocytic differentiated mesenchymal stem cells for translational research

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brückner, Sandra, E-mail: sandra.brueckner@medizin.uni-leipzig.de; Tautenhahn, Hans-Michael, E-mail: hans-michael.tautenhahn@medizin.uni-leipzig.de; TRM, Translational Centre for Regenerative Medicine, Philipp-Rosenthal-Str. 55, Leipzig D-04103

Study background: Extended liver resection is the only curative treatment option of liver cancer. Yet, the residual liver may not accomplish the high metabolic and regenerative capacity needed, which frequently leads to acute liver failure. Because of their anti-inflammatory and -apoptotic as well as pro-proliferative features, mesenchymal stem cells differentiated into hepatocyte-like cells might provide functional and regenerative compensation. Clinical translation of basic research requires pre-clinical approval in large animals. Therefore, we characterized porcine mesenchymal stem cells (MSC) from adipose tissue and bone marrow and their hepatocyte differentiation potential for future assessment of functional liver support after surgical intervention inmore » the pig model. Methods: Mesenchymal surface antigens and multi-lineage differentiation potential of porcine MSC isolated by collagenase digestion either from bone marrow or adipose tissue (subcutaneous/visceral) were assessed by flow cytometry. Morphology and functional properties (urea-, glycogen synthesis and cytochrome P450 activity) were determined during culture under differentiation conditions and compared with primary porcine hepatocytes. Results: MSC from porcine adipose tissue and from bone marrow express the typical mesenchymal markers CD44, CD29, CD90 and CD105 but not haematopoietic markers. MSC from both sources displayed differentiation into the osteogenic as well as adipogenic lineage. After hepatocyte differentiation, expression of CD105 decreased significantly and cells adopted the typical polygonal morphology of hepatocytes. Glycogen storage was comparable in adipose tissue- and bone marrow-derived cells. Urea synthesis was about 35% lower in visceral than in subcutaneous adipose tissue-derived MSC. Cytochrome P450 activity increased significantly during differentiation and was twice as high in hepatocyte-like cells generated from bone marrow as from adipose tissue. Conclusion: The hepatocyte differentiation of porcine adipose tissue-derived MSC was shown for the first time yielding hepatocyte-like cells with specific functions similar in bone marrow and subcutaneous adipose tissue-derived MSC. That makes them good pre-clinical candidates for supportive approaches after liver resection in the pig. - Highlights: • First time to show hepatocytic differentiation of porcine adipose tissue-derived MSC. • Hepatocytic-differentiated MSC display metabolic qualities of primary hepatocytes. • Metabolic potency varies between differentiated MSC from different tissues. • MSC are good candidates for pre-clinical evaluation of stem cell-based therapies.« less

Culture-expanded mesenchymal stem cell sheets enhance extraction-site alveolar bone growth: An animal study.

PubMed

Mu, S; Tee, B C; Emam, H; Zhou, Y; Sun, Z

2018-04-06

Impaired bone formation of the buccal alveolar plate after tooth extraction during adolescence increases the difficulty of future implant restoration. This study was undertaken to assess the feasibility and efficacy of transplanting autogenous scaffold-free culture-expanded mesenchymal stem cell (MSC) sheets to the buccal alveolar bone surface to stimulate local bone growth. Mandibular bone marrow was aspirated from 3-month-old pigs (n = 5), from which MSCs were isolated and culture expanded. Triple-layer MSC sheets were then fabricated using temperature-responsive tissue culture plates. One month after bone marrow aspirations, the same pigs underwent bilateral extraction of mandibular primary molars, immediately followed by transplantation of 3 autogenous triple-layer MSC sheets on to the subperiosteal buccal alveolar surface of 1 randomly chosen side. The contralateral side (control) underwent the same periosteal reflection surgery without receiving MSC sheet transplantation. Six weeks later, the animals were killed and specimens from both sides were immediately harvested for radiographic and histological analysis. Buccal alveolar bone thickness, tissue mineral density (TMD), mineral apposition and bone volume fraction (BV/TV) were quantified and compared between the MSC sheet and control sides using paired t-tests. Triple-layer MSC sheets were reliably fabricated and the majority of cells remained vital before transplantation. The thickness of buccal bone tended to increase with MSC sheet transplantation (P = .18), with 4 of 5 animals showing an average of 1.82 ± 0.73 mm thicker bone on the MSC sheet side than the control side. After being normalized by the TMD of intracortical bone, the TMD of surface cortical bone was 0.5-fold higher on the MSC sheet side than the control side (P < .05). Likewise, the BV/TV measurements of the buccal surface region were also 0.4-fold higher on the MSC sheet side than the control side (P < .05) after being normalized by measurements from the intracortical region. Mineral apposition measurements were not different between the 2 sides. Mandibular marrow-derived MSCs can be fabricated into cell sheets and autogenous transplantation of MSC sheets onto the subperiosteal buccal alveolar bone surface at the tooth-extraction site may increase local bone density. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Mesenchymal Stromal Cell-Derived Extracellular Vesicles Protect the Fetal Brain After Hypoxia-Ischemia.

PubMed

Ophelders, Daan R M G; Wolfs, Tim G A M; Jellema, Reint K; Zwanenburg, Alex; Andriessen, Peter; Delhaas, Tammo; Ludwig, Anna-Kristin; Radtke, Stefan; Peters, Vera; Janssen, Leon; Giebel, Bernd; Kramer, Boris W

2016-06-01

Preterm neonates are susceptible to perinatal hypoxic-ischemic brain injury, for which no treatment is available. In a preclinical animal model of hypoxic-ischemic brain injury in ovine fetuses, we have demonstrated the neuroprotective potential of systemically administered mesenchymal stromal cells (MSCs). The mechanism of MSC treatment is unclear but suggested to be paracrine, through secretion of extracellular vesicles (EVs). Therefore, we investigated in this study the protective effects of mesenchymal stromal cell-derived extracellular vesicles (MSC-EVs) in a preclinical model of preterm hypoxic-ischemic brain injury. Ovine fetuses were subjected to global hypoxia-ischemia by transient umbilical cord occlusion, followed by in utero intravenous administration of MSC-EVs. The therapeutic effects of MSC-EV administration were assessed by analysis of electrophysiological parameters and histology of the brain. Systemic administration of MSC-EVs improved brain function by reducing the total number and duration of seizures, and by preserving baroreceptor reflex sensitivity. These functional protections were accompanied by a tendency to prevent hypomyelination. Cerebral inflammation remained unaffected by the MSC-EV treatment. Our data demonstrate that MSC-EV treatment might provide a novel strategy to reduce the neurological sequelae following hypoxic-ischemic injury of the preterm brain. Our study results suggest that a cell-free preparation comprising neuroprotective MSC-EVs could substitute MSCs in the treatment of preterm neonates with hypoxic-ischemic brain injury, thereby circumventing the potential risks of systemic administration of living cells. Bone marrow-derived mesenchymal stromal cells (MSCs) show promise in treating hypoxic-ischemic injury of the preterm brain. Study results suggest administration of extracellular vesicles, rather than intact MSCs, is sufficient to exert therapeutic effects and avoids potential concerns associated with administration of living cells. The therapeutic efficacy of systemically administered mesenchymal stromal cell-derived extracellular vesicles (MSC-EVs) on hypoxia-ischemia-induced injury was assessed in the preterm ovine brain. Impaired function and structural injury of the fetal brain was improved following global hypoxia-ischemia. A cell-free preparation of MSC-EVs could substitute for the cellular counterpart in the treatment of preterm neonates with hypoxic-ischemic brain injury. This may open new clinical applications for "off-the-shelf" interventions with MSC-EVs. ©AlphaMed Press.

Intravenous adipose-derived mesenchymal stem cell therapy for the treatment of feline asthma: a pilot study.

PubMed

Trzil, Julie E; Masseau, Isabelle; Webb, Tracy L; Chang, Chee-Hoon; Dodam, John R; Liu, Hong; Quimby, Jessica M; Dow, Steven W; Reinero, Carol R

2016-12-01

The aim of this study was to evaluate the feasibility and efficacy of serially administered adipose-derived mesenchymal stem cells (MSCs) in an experimental feline asthma model. Allergic asthma was acutely induced with Bermuda grass allergen in six purpose-bred cats. Five intravenous infusions of allogeneic MSCs (n = 4; MSC-treated) or saline (n = 2; placebo-treated) were administered over the first 130 days after asthma induction. Infusions contained 2 × 10 6 , 4 × 10 6 , 4.7 × 10 6 , 1 × 10 7 and 1 × 10 7 cryopreserved MSCs/cat. For thoracic imaging additional cats were enrolled as control groups: four untreated, experimentally asthmatic cats (combined with placebo-treated cats), and six healthy, non-asthmatic cats. Outcome measures included airway eosinophilia, pulmonary mechanics, thoracic computed tomography and several immunologic assays. Cats were assessed for 9 months after treatment. At early points, airway eosinophil percentage was not affected by MSC administration (post-treatment average of days 12, 26, 47, 108 and 133 in MSC-treated cats was 41 ± 15% and in placebo-treated cats it was 34 ± 16%). By month 9, eosinophil percentages in all MSC-treated cats decreased to normal reference intervals (MSC-treated 6%; placebo-treated 20%; normal <17%). Diminished airway hyper-responsiveness was noted in all MSC-treated compared with placebo-treated cats at day 133 (dose of methacholine to double baseline airway resistance: MSC-treated median 22.9 mg/ml [range 6.4-64.0]; individual placebo-treated cats 1.1 and 5.0 mg/ml). Lung attenuation (mean ± SEM MSC-treated -865 ± 12 Hounsfield units [HU]; untreated asthmatics -820 ± 11 HU; P = 0.004) and bronchial wall thickening scores (median [interquartile range] MSC-treated 0 [0-1.5]; untreated asthmatic 11.6 [7.3-27.3]; P = 0.010) were significantly reduced in MSC-treated vs untreated asthmatic cats, consistent with decreased airway remodeling at month 9. No clear immunologic mechanisms by which MSCs act were determined. MSCs may have a delayed effect in reducing airway inflammation, airway hyper-responsiveness and remodeling in experimentally induced asthmatic cats. Results warrant additional investigation of MSC therapy for asthma in cats. © The Author(s) 2015.

16. NBS TOPSIDE CONTROL ROOM, THE NBS HYPERBARIC CHAMBER IS ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

16. NBS TOPSIDE CONTROL ROOM, THE NBS HYPERBARIC CHAMBER IS VERY CLOSE TO THE WATER'S EDGE AND HERE FOR DIVER EMERGENCY SUPPORT. A MEDICAL STAFF IS LOCATED ON THE MARSHALL SPACE FLIGHT CENTER (MSFC) AND SUPPORTS THE NBS PERSONNEL WHEN HYPERBARIC CHAMBER OPERATION IS NECESSARY. - Marshall Space Flight Center, Neutral Buoyancy Simulator Facility, Rideout Road, Huntsville, Madison County, AL

Shock-Induced Heating In A Rocket Engine

NASA Technical Reports Server (NTRS)

Lagnado, Ronald R.; Raiszadeh, Farhad

1989-01-01

Misalignments give rise to hotspots on walls. Report discusses numerical simulation of flow in and near small, ringlike cavity in wall of Space Shuttle main engine at junction of main combustion chamber and nozzle. Purpose to study effects of misalignments between combustion chamber and nozzle on transfer of heat into surfaces chamber, cavity, and nozzle. Depending on specific misalignment flow encounters forward-or backward-facing step leaving chamber and entering nozzle. Results in serious losses of performance and excessive heating of walls.

Study of low speed flow cytometry for diffraction imaging with different chamber and nozzle designs.

PubMed

Sa, Yu; Feng, Yuanming; Jacobs, Kenneth M; Yang, Jun; Pan, Ran; Gkigkitzis, Ioannis; Lu, Jun Q; Hu, Xin-Hua

2013-11-01

Achieving effective hydrodynamic focusing and flow stability at low speed presents a challenging design task in flow cytometry for studying phenomena such as cell adhesion and diffraction imaging of cells with low-cost cameras. We have developed different designs of flow chamber and sheath nozzle to accomplish the above goal. A 3D computational model of the chambers has been established to simulate the fluid dynamics in different chamber designs and measurements have been performed to determine the velocity and size distributions of the core fluid from the nozzle. Comparison of the simulation data with experimental results shows good agreement. With the computational model significant insights were gained for optimization of the chamber design and improvement of the cell positioning accuracy for study of slow moving cells. The benefit of low flow speed has been demonstrated also by reduced blurring in the diffraction images of single cells. Based on these results, we concluded that the new designs of chamber and sheath nozzle produce stable hydrodynamic focusing of the core fluid at low speed and allow detailed study of cellular morphology under various rheological conditions using the diffraction imaging method. © 2013 International Society for Advancement of Cytometry.

Deployment and testing of a second prototype expandable surgical chamber in microgravity

NASA Technical Reports Server (NTRS)

Markham, Sanford M.; Rock, John A.

1991-01-01

During microgravity exposure, two separate expandable surgical chambers were tested. Both chambers had been modified to fit the microgravity work station without extending over the sides of the table. Both chambers were attached to a portable laminar flow generator which served two purposes: to keep the chambers expanded during use; and to provide an operative area environment free of contamination. During the tests, the chambers were placed on various parts of a total body moulage to simulate management of several types of trauma. The tests consisted of cleansing contusions, debridement of burns, and suturing of lacerations. Also, indigo carmine dye was deliberately injected into the chamber during the tests to determine the ease of cleansing the chamber walls after contamination by escaping fluids. Upon completion of the tests, the expandable surgical chambers were deflated, folded, and placed in a flattened state back into their original containers for storage and later disposal. Results are briefly discussed.

Investigation of particle and vapor wall-loss effects on controlled wood-smoke smog-chamber experiments

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bian, Q.; May, A. A.; Kreidenweis, Sonia M.

Here, smog chambers are extensively used to study processes that drive gas and particle evolution in the atmosphere. A limitation of these experiments is that particles and gas-phase species may be lost to chamber walls on shorter timescales than the timescales of the atmospheric processes being studied in the chamber experiments. These particle and vapor wall losses have been investigated in recent studies of secondary organic aerosol (SOA) formation, but they have not been systematically investigated in experiments of primary emissions from combustion. The semi-volatile nature of combustion emissions (e.g. from wood smoke) may complicate the behavior of particle andmore » vapor wall deposition in the chamber over the course of the experiments due to the competition between gas/particle and gas/wall partitioning. Losses of vapors to the walls may impact particle evaporation in these experiments, and potential precursors for SOA formation from combustion may be lost to the walls, causing underestimations of aerosol yields. Here, we conduct simulations to determine how particle and gas-phase wall losses contributed to the observed evolution of the aerosol during experiments in the third Fire Lab At Missoula Experiment (FLAME III). We use the TwO-Moment Aerosol Sectional (TOMAS) microphysics algorithm coupled with the organic volatility basis set (VBS) and wall-loss formulations to examine the predicted extent of particle and vapor wall losses. We limit the scope of our study to the dark periods in the chamber before photo-oxidation to simplify the aerosol system for this initial study. Our model simulations suggest that over one-third of the initial particle-phase organic mass (41 %) was lost during the experiments, and over half of this particle-organic mass loss was from direct particle wall loss (65 % of the loss) with the remainder from evaporation of the particles driven by vapor losses to the walls (35 % of the loss). We perform a series of sensitivity tests to understand uncertainties in our simulations. Uncertainty in the initial wood-smoke volatility distribution contributes 18 % uncertainty to the final particle-organic mass remaining in the chamber (relative to base-assumption simulation). We show that the total mass loss may depend on the effective saturation concentration of vapor with respect to the walls as these values currently vary widely in the literature. The details of smoke dilution during the filling of smog chambers may influence the mass loss to the walls, and a dilution of ~ 25:1 during the experiments increased particle-organic mass loss by 33 % compared to a simulation where we assume the particles and vapors are initially in equilibrium in the chamber. Finally, we discuss how our findings may influence interpretations of emission factors and SOA production in wood-smoke smog-chamber experiments.« less

Exosomal Signaling during Hypoxia Mediates Microvascular Endothelial Cell Migration and Vasculogenesis

PubMed Central

Salomon, Carlos; Ryan, Jennifer; Sobrevia, Luis; Kobayashi, Miharu; Ashman, Keith; Mitchell, Murray; Rice, Gregory E.

2013-01-01

Vasculogenesis and angiogenesis are critical processes in fetal circulation and placental vasculature development. Placental mesenchymal stem cells (pMSC) are known to release paracrine factors (some of which are contained within exosomes) that promote angiogenesis and cell migration. The aims of this study were: to determine the effects of oxygen tension on the release of exosomes from pMSC; and to establish the effects of pMSC-derived exosomes on the migration and angiogenic tube formation of placental microvascular endothelial cells (hPMEC). pMSC were isolated from placental villi (8–12 weeks of gestation, n = 6) and cultured under an atmosphere of 1%, 3% or 8% O2. Cell-conditioned media were collected and exosomes (exo-pMSC) isolated by differential and buoyant density centrifugation. The dose effect (5–20 µg exosomal protein/ml) of pMSC-derived exosomes on hPMEC migration and tube formation were established using a real-time, live-cell imaging system (Incucyte™). The exosome pellet was resuspended in PBS and protein content was established by mass spectrometry (MS). Protein function and canonical pathways were identified using the PANTHER program and Ingenuity Pathway Analysis, respectively. Exo-pMSC were identified, by electron microscopy, as spherical vesicles, with a typical cup-shape and diameters around of 100 nm and positive for exosome markers: CD63, CD9 and CD81. Under hypoxic conditions (1% and 3% O2) exo-pMSC released increased by 3.3 and 6.7 folds, respectively, when compared to the controls (8% O2; p<0.01). Exo-pMSC increased hPMEC migration by 1.6 fold compared to the control (p<0.05) and increased hPMEC tube formation by 7.2 fold (p<0.05). MS analysis identified 390 different proteins involved in cytoskeleton organization, development, immunomodulatory, and cell-to-cell communication. The data obtained support the hypothesis that pMSC-derived exosomes may contribute to placental vascular adaptation to low oxygen tension under both physiological and pathological conditions. PMID:23861904

Platelet-Derived Growth Factor-BB Protects Mesenchymal Stem Cells (MSCs) Derived From Immune Thrombocytopenia Patients Against Apoptosis and Senescence and Maintains MSC-Mediated Immunosuppression

PubMed Central

Zhang, Jia-min; Feng, Fei-er; Wang, Qian-ming; Zhu, Xiao-lu; Fu, Hai-xia; Xu, Lan-ping; Liu, Kai-yan

2016-01-01

Immune thrombocytopenia (ITP) is characterized by platelet destruction and megakaryocyte dysfunction. Mesenchymal stem cells (MSCs) from ITP patients (MSC-ITP) do not exhibit conventional proliferative abilities and thus exhibit defects in immunoregulation, suggesting that MSC impairment might be a mechanism involved in ITP. Platelet-derived growth factor (PDGF) improves growth and survival in various cell types. Moreover, PDGF promotes MSC proliferation. The aim of the present study was to analyze the effects of PDGF-BB on MSC-ITP. We showed that MSC-ITP expanded more slowly and appeared flattened and larger. MSC-ITP exhibited increased apoptosis and senescence compared with controls. Both the intrinsic and extrinsic pathways account for the enhanced apoptosis. P53 and p21 expression were upregulated in MSC-ITP, but inhibition of p53 with pifithrin-α markedly inhibited apoptosis and senescence. Furthermore, MSCs from ITP patients showed a lower capacity for inhibiting the proliferation of activated T cells inducing regulatory T cells (Tregs) and suppressing the synthesis of anti-glycoprotein (GP)IIb-IIIa antibodies. PDGF-BB treatment significantly decreased the expression of p53 and p21 and increased survivin expression in MSC-ITP. In addition, the apoptotic rate and number of senescent cells in ITP MSCs were reduced. Their impaired ability for inhibiting activated T cells, inducing Tregs, and suppressing the synthesis of anti-GPIIb-IIIa antibodies was restored after PDGF-BB treatment. In conclusion, we have demonstrated that PDGF-BB protects MSCs derived from ITP patients against apoptosis, senescence, and immunomodulatory defects. This protective effect of PDGF-BB is likely mediated via the p53/p21 pathway, thus potentially providing a new therapeutic approach for ITP. Significance Immune thrombocytopenia (ITP) is characterized by platelet destruction and megakaryocyte dysfunction. Platelet-derived growth factor (PDGF) improves growth and survival in various cell types and promotes mesenchymal stem cell (MSC) proliferation. PDGF-BB protects MSCs derived from ITP patients against apoptosis, senescence, and immunomodulatory defects. This protective effect of PDGF-BB is likely mediated via the p53/p21 pathway, thus potentially providing a new therapeutic approach for ITP. PMID:27471307

Study on optimization of multiionization-chamber system for BNCT.

PubMed

Fujii, T; Tanaka, H; Maruhashi, A; Ono, K; Sakurai, Y

2011-12-01

In order to monitor stability of doses from the four components such as thermal, epi-thermal, fast neutron and gamma-ray during BNCT irradiation, we are developing a multiionization-chamber system. This system is consisted of four kinds of ionization chamber, which have specific sensitivity for each component, respectively. Since a suitable structure for each chamber depends on the energy spectrum of the irradiation field, the optimization study of the chamber structures for the epi-thermal neutron beam of cyclotron-based epi-thermal neutron source (C-BENS) was performed by using a Monte Carlo simulation code "PHITS" and suitable chamber-structures were determined. Copyright © 2011 Elsevier Ltd. All rights reserved.

Dynamic Finite Element Predictions for Mars Sample Return Cellular Impact Test #4

NASA Technical Reports Server (NTRS)

Fasanella, Edwin L.; Billings, Marcus D.

2001-01-01

The nonlinear finite element program MSC.Dytran was used to predict the impact pulse for (he drop test of an energy absorbing cellular structure. This pre-test simulation was performed to aid in the design of an energy absorbing concept for a highly reliable passive Earth Entry Vehicle (EEV) that will directly impact the Earth without a parachute. In addition, a goal of the simulation was to bound the acceleration pulse produced and delivered to the simulated space cargo container. EEV's are designed to return materials from asteroids, comets, or planets for laboratory analysis on Earth. The EEV concept uses an energy absorbing cellular structure designed to contain and limit the acceleration of space exploration samples during Earth impact. The spherical shaped cellular structure is composed of solid hexagonal and pentagonal foam-filled cells with hybrid graphite-epoxy/Kevlar cell walls. Space samples fit inside a smaller sphere at the enter of the EEV's cellular structure. The material models and failure criteria were varied to determine their effect on the resulting acceleration pulse. Pre-test analytical predictions using MSC.Dytran were compared with the test results obtained from impact test #4 using bungee accelerator located at the NASA Langley Research Center Impact Dynamics Research Facility. The material model used to represent the foam and the proper failure criteria for the cell walls were critical in predicting the impact loads of the cellular structure. It was determined that a FOAMI model for the foam and a 20% failure strain criteria for the cell walls gave an accurate prediction of the acceleration pulse for drop test #4.

Simulated annealing algorithm for solving chambering student-case assignment problem

NASA Astrophysics Data System (ADS)

Ghazali, Saadiah; Abdul-Rahman, Syariza

2015-12-01

The problem related to project assignment problem is one of popular practical problem that appear nowadays. The challenge of solving the problem raise whenever the complexity related to preferences, the existence of real-world constraints and problem size increased. This study focuses on solving a chambering student-case assignment problem by using a simulated annealing algorithm where this problem is classified under project assignment problem. The project assignment problem is considered as hard combinatorial optimization problem and solving it using a metaheuristic approach is an advantage because it could return a good solution in a reasonable time. The problem of assigning chambering students to cases has never been addressed in the literature before. For the proposed problem, it is essential for law graduates to peruse in chambers before they are qualified to become legal counselor. Thus, assigning the chambering students to cases is a critically needed especially when involving many preferences. Hence, this study presents a preliminary study of the proposed project assignment problem. The objective of the study is to minimize the total completion time for all students in solving the given cases. This study employed a minimum cost greedy heuristic in order to construct a feasible initial solution. The search then is preceded with a simulated annealing algorithm for further improvement of solution quality. The analysis of the obtained result has shown that the proposed simulated annealing algorithm has greatly improved the solution constructed by the minimum cost greedy heuristic. Hence, this research has demonstrated the advantages of solving project assignment problem by using metaheuristic techniques.

Magnetic Search Coil (MSC) of Plasma Wave Experiment (PWE) aboard the Arase (ERG) satellite

NASA Astrophysics Data System (ADS)

Ozaki, Mitsunori; Yagitani, Satoshi; Kasahara, Yoshiya; Kojima, Hirotsugu; Kasaba, Yasumasa; Kumamoto, Atsushi; Tsuchiya, Fuminori; Matsuda, Shoya; Matsuoka, Ayako; Sasaki, Takashi; Yumoto, Takahiro

2018-05-01

This paper presents detailed performance values of the Magnetic Search Coil (MSC) that is part of the Plasma Wave Experiment on board the Arase (ERG) satellite. The MSC consists of a three-axis search coil magnetometer with a 200-mm-long magnetic core. The MSC plays a central role in the magnetic field observations, particularly for whistler mode chorus and hiss waves in a few kHz frequency range, which may cause local acceleration and/or rapid loss of radiation belt electrons. Accordingly, the MSC was carefully designed and developed to operate well in harsh radiation environments. To ascertain the wave-normal vectors, polarizations, and refractive indices of the plasma waves in a wide frequency band, the output signals detected by the MSC are fed into the two different wave receivers: one is the WaveForm Capture/Onboard Frequency Analyzer for waveform and spectrum observations in the frequency range from a few Hz up to 20 kHz, and the other is the High Frequency Analyzer for spectrum observations in the frequency range from 10 to 100 kHz. The noise equivalent magnetic induction of the MSC is 20 {fT/Hz}^{1/2} at a frequency of 2 kHz, and the null depth of directionality is - 40 dB, which is equivalent to an angular error less than 1°. The MSC on board the Arase satellite is the first experiment using a current-sensitive preamplifier for probing the plasma waves in the radiation belts.[Figure not available: see fulltext.

Cardiac mesenchymal stromal cells are a source of adipocytes in arrhythmogenic cardiomyopathy

PubMed Central

Sommariva, E.; Brambilla, S.; Carbucicchio, C.; Gambini, E.; Meraviglia, V.; Dello Russo, A.; Farina, F.M.; Casella, M.; Catto, V.; Pontone, G.; Chiesa, M.; Stadiotti, I.; Cogliati, E.; Paolin, A.; Ouali Alami, N.; Preziuso, C.; d'Amati, G.; Colombo, G.I.; Rossini, A.; Capogrossi, M.C.; Tondo, C.; Pompilio, G.

2016-01-01

Abstract Aim Arrhythmogenic cardiomyopathy (ACM) is a genetic disorder mainly due to mutations in desmosomal genes, characterized by progressive fibro-adipose replacement of the myocardium, arrhythmias, and sudden death. It is still unclear which cell type is responsible for fibro-adipose substitution and which molecular mechanisms lead to this structural change. Cardiac mesenchymal stromal cells (C-MSC) are the most abundant cells in the heart, with propensity to differentiate into several cell types, including adipocytes, and their role in ACM is unknown. The aim of the present study was to investigate whether C-MSC contributed to excess adipocytes in patients with ACM. Methods and results We found that, in ACM patients' explanted heart sections, cells actively differentiating into adipocytes are of mesenchymal origin. Therefore, we isolated C-MSC from endomyocardial biopsies of ACM and from not affected by arrhythmogenic cardiomyopathy (NON-ACM) (control) patients. We found that both ACM and control C-MSC express desmosomal genes, with ACM C-MSC showing lower expression of plakophilin (PKP2) protein vs. controls. Arrhythmogenic cardiomyopathy C-MSC cultured in adipogenic medium accumulated more lipid droplets than controls. Accordingly, the expression of adipogenic genes was higher in ACM vs. NON-ACM C-MSC, while expression of cell cycle and anti-adipogenic genes was lower. Both lipid accumulation and transcription reprogramming were dependent on PKP2 deficiency. Conclusions Cardiac mesenchymal stromal cells contribute to the adipogenic substitution observed in ACM patients' hearts. Moreover, C-MSC from ACM patients recapitulate the features of ACM adipogenesis, representing a novel, scalable, patient-specific in vitro tool for future mechanistic studies. PMID:26590176

HDAC8 overexpression in mesenchymal stromal cells from JAK2+ myeloproliferative neoplasms: a new therapeutic target?

PubMed Central

Ramos, Teresa L.; Sánchez-Abarca, Luis Ignacio; Redondo, Alba; Hernández-Hernández, Ángel; Almeida, Antonio M.; Puig, Noemí; Rodríguez, Concepción; Ortega, Rebeca; Preciado, Silvia; Rico, Ana; Muntión, Sandra; González Porras, José Ramón; Cañizo, Consuelo Del; Sánchez-Guijo, Fermín

2017-01-01

Histone deacetylases (HDACs) are involved in epigenetic modulation and their aberrant expression has been demonstrated in myeloproliferative neoplasms (MPN). HDAC8 inhibition has been shown to inhibit JAK2/STAT5 signaling in hematopoietic cells from MPN. Nevertheless, the role of HDAC8 expression in bone marrow-mesenchymal stromal cells (BM-MSC) has not been assessed. In the current work we describe that HDAC8 is significantly over-expressed in MSC from in JAK-2 positive MPN compared to those from healthy-donors (HD-MSC). Using a selective HDAC8 inhibitor (PCI34051), we verified that the subsequent decrease in the protein and mRNA expression of HDAC8 is linked with an increased apoptosis of malignant MSC whereas it has no effects on normal MSC. In addition, HDAC8 inhibition in MPN-MSC also decreased their capacity to maintain neoplastic hematopoiesis, by increasing the apoptosis, cell-cycle arrest and colony formation of JAK2+-hematopoietic cells. Mechanistic studies using different MPN cell lines revealed that PCI34051 induced their apoptosis, which is enhanced when were co-cultured with JAK2V617F-MSC, decreased their colony formation and the phosphorylation of STAT3 and STAT5. In summary, we show for the first time that the inhibition of HDAC8 in MSC from JAK2+ MPN patients selectively decreases their hematopoietic-supporting ability, suggesting that HDAC8 may be a potential therapeutic target in this setting by acting not only on hematopoietic cells but also on the malignant microenvironment. PMID:28390197

EFFECTS OF PLATING DENSITY AND CULTURE TIME ON BONE MARROW STROMAL CELL CHARACTERISTICS

PubMed Central

Neuhuber, Birgit; Swanger, Sharon A.; Howard, Linda; Mackay, Alastair; Fischer, Itzhak

2008-01-01

Objective Bone marrow stromal cells (MSC) are multipotent adult stem cells that have emerged as promising candidates for cell therapy in disorders including cardiac infarction, stroke and spinal cord injury. While harvesting methods used by different laboratories are relatively standard, MSC culturing protocols vary widely. This study is aimed at evaluating the effects of initial plating density and total time in culture on proliferation, cell morphology, and differentiation potential of heterogeneous MSC cultures and more homogeneous cloned subpopulations. Methods Rat MSC were plated at 20, 200 and 2000 cells/cm2 and grown to 50% confluency. The numbers of population doublings and doubling times were determined within and across multiple passages. Changes in cell morphology and differentiation potential to adipogenic, chondrogenic, and osteogenic lineages were evaluated and compared among early, intermediate and late passages, as well as between heterogeneous and cloned MSC populations. Results We found optimal cell growth at a plating density of 200 cells/cm2. Cultures derived from all plating densities developed increased proportions of flat cells over time. Assays for chondrogenesis, osteogenesis and adipogenesis showed that heterogeneous MSC plated at all densities sustained the potential for all three mesenchymal phenotypes through at least passage 5; the flat subpopulation lost adipogenic and chondrogenic potential. Conclusion Our findings suggest that the initial plating density is not critical for maintaining a well-defined, multipotent MSC population. Time in culture, however, affects cell characteristics, suggesting that cell expansion should be limited, especially until the specific characteristics of different MSC subpopulations are better understood. PMID:18495329

The plant homeodomain fingers of fission yeast Msc1 exhibit E3 ubiquitin ligase activity.

PubMed

Dul, Barbara E; Walworth, Nancy C

2007-06-22

The DNA damage checkpoint pathway governs how cells regulate cell cycle progression in response to DNA damage. A screen for suppressors of a fission yeast chk1 mutant defective in the checkpoint pathway identified a novel Schizosaccharomyces pombe protein, Msc1. Msc1 contains 3 plant homeodomain (PHD) finger motifs, characteristically defined by a C4HC3 consensus similar to RING finger domains. PHD finger domains in viral proteins and in the cellular protein kinase MEKK1 (mitogen-activated protein kinase/extracellular signal-regulated kinase kinase kinase 1) have been implicated as ubiquitin E3 protein ligases that affect protein stability. The close structural relationship of PHD fingers to RING fingers suggests that other PHD domain-containing proteins might share this activity. We show that each of the three PHD fingers of Msc1 can act as ubiquitin E3 ligases, reporting for the first time that PHD fingers from a nuclear protein exhibit E3 ubiquitin ligase activity. The function of the PHD fingers of Msc1 is needed to rescue the DNA damage sensitivity of a chk1Delta strain. Msc1 co-precipitates Rhp6, the S. pombe homologue of the human ubiquitin-conjugating enzyme Ubc2. Strikingly, deletion of msc1 confers complete suppression of the slow growth phenotype, UV and hydroxyurea sensitivities of an rhp6 deletion strain and restores deficient histone H3 methylation observed in the rhp6Delta mutant. We speculate that the target of the E3 ubiquitin ligase activity of Msc1 is likely to be a chromatin-associated protein.

Differentiation of human umbilical cord mesenchymal stromal cells into low immunogenic hepatocyte-like cells.

PubMed

Zhao, Qinjun; Ren, Hongying; Li, Xiyuan; Chen, Zhong; Zhang, Xiangyu; Gong, Wei; Liu, Yongjun; Pang, Tianxiang; Han, Zhong Chao

2009-01-01

Mesenchymal stromal cells (MSC) isolated from several human tissues have been known to differentiate into the hepatic lineage in vitro, but the immunogenicity of the differentiated hepatocyte-like cells (DHC) has not been reported. Umbilical cord (UC) MSC are thought to be an attractive cell source for cell therapy because of their young age and low infection rate compared with adult tissue MSC. Hepatic differentiation of UC-MSC was induced with a 2-step protocol. The expressions of hepatic markers were detected by RT-PCR and immunofluorescence staining. Albumin production and urea secretion were measured by ELISA and colorimetric assay respectively. The immunosuppressive properties of DHC was detected by mixed lymphocyte culture. After incubation with specific growth factors, including hepatocyte growth factor (HGF) and basic fibroblast growth factor (bFGF), UC MSC exhibited a high hepatic differentiation ability in an adherent culture condition. The differentiated UC MSC showed hepatocyte-like morphology and expressed several liver-specific markers at gene and protein levels. Furthermore, the DHC exhibited hepatocyte-specific functions, including albumin secretion, low-density lipoprotein uptake and urea production. More importantly, DHC did not express major histocompatibility complex (MHC) II antigen and were not able to induce lymphocyte proliferation in mixed lymphocyte culture, as undifferentiated UC MSC did. Our results indicate that UC MSC are able to differentiate into functional hepatocyte-like cells that still retain their low immunogenicity in vitro. More importantly, DHC incorporated into the parenchyma of liver when transplanted into mice with CCl(4)-induced liver injury. Therefore, DHC may be an ideal source for cell therapy of liver diseases.

A Reproducible Immunopotency Assay to Measure Mesenchymal Stromal Cell Mediated T cell Suppression

PubMed Central

Bloom, Debra D.; Centanni, John M.; Bhatia, Neehar; Emler, Carol A.; Drier, Diana; Leverson, Glen E.; McKenna, David H.; Gee, Adrian P.; Lindblad, Robert; Hei, Derek J.; Hematti, Peiman

2014-01-01

Background The T cell suppressive property of bone marrow derived mesenchymal stromal cells (MSCs) has been considered a major mode of action and basis for their utilization in a number of human clinical trials. However, there is no well-established reproducible assay to measure MSC-mediated T cell suppression. Methods At the University of Wisconsin-Madison Production Assistance for Cellular Therapy (PACT) Center we developed an in vitro quality control T cell suppression immunopotency assay (IPA) which utilizes anti-CD3 and anti-CD28 antibodies to stimulate T cell proliferation. We measured MSC-induced suppression of CD4+ T cell proliferation at various effector to target cell ratios using defined peripheral blood mononuclear cells and in parallel compared to a reference standard MSC product. We calculated an IPA value for suppression of CD4+ T cells for each MSC product. Results Eleven MSC products generated at three independent PACT centers were evaluated for cell surface phenotypic markers and T cell suppressive properties. Flow cytometry results demonstrated typical MSC cell surface marker profiles. There was significant variability in the level of suppression of T cell proliferation with IPA values ranging from 27% to 88%. However, MSC suppression did not correlate with HLA-DR expression. Discussion We have developed a reproducible immunopotency assay to measure allogeneic MSC-mediated suppression of CD4+ T cells. Additional studies may be warranted to determine how these in vitro assay results may correlate with other immunomodulatory properties of MSCs, in addition to evaluating the ability of this assay to predict in vivo efficacy. PMID:25455739

Conditioned medium from human bone marrow-derived mesenchymal stem cells promotes skin moisturization and effacement of wrinkles in UVB-irradiated SKH-1 hairless mice.

PubMed

Kwon, Tae-Rin; Oh, Chang Taek; Choi, Eun Ja; Kim, Soon Re; Jang, Yu-Jin; Ko, Eun Jung; Yoo, Kwang Ho; Kim, Beom Joon

2016-05-01

Mesenchymal stem cells (MSCs) are promising therapeutic agents for various diseases. To investigate the effects of conditioned medium from human bone marrow-derived mesenchymal stem cells (MSC-CdM) on pro-collagen production and wrinkle formation, we performed in vitro and in vivo experiments. We assessed the effects of MSC-CdM on proliferation and photo-aging in human dermal fibroblasts after UVB exposure using enzyme activity assays for collagen type I secretion and MMP-1. To determine the effect of topically applied MSC-CdM on wrinkle formation, MSC-CdM (1% and 10%) and vehicle (propylene glycol: ethanol, 7 : 3) were applied to the dorsal skin of UVB-irradiated hairless mice for 8 weeks. We examined the effects on wrinkle formation by assessing visual skin grading, replica, tape stripping, transepidermal water loss (TEWL), and skin hydration measurement. We also examined histology of the lesions using hematoxylin-eosin, Masson's trichrome, and immunohistochemical staining. MSC-CdM markedly reduced UV-induced matrix metalloproteinase-1 expression and increased pro-collagen synthesis in a dose-dependent manner. Our findings suggest that MSC-CdM induces repair of dermal damage and effacement of wrinkles on UVB-irradiated hairless mice through protective effect of hydration. These results support an anti-wrinkle effect of MSC-CdM that involves increased collagen synthesis and suggest that MSC-CdM might be a potential candidate for preventing UV-induced skin damage. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

A large high vacuum, high pumping speed space simulation chamber for electric propulsion

NASA Technical Reports Server (NTRS)

Grisnik, Stanley P.; Parkes, James E.

1994-01-01

Testing high power electric propulsion devices poses unique requirements on space simulation facilities. Very high pumping speeds are required to maintain high vacuum levels while handling large volumes of exhaust products. These pumping speeds are significantly higher than those available in most existing vacuum facilities. There is also a requirement for relatively large vacuum chamber dimensions to minimize facility wall/thruster plume interactions and to accommodate far field plume diagnostic measurements. A 4.57 m (15 ft) diameter by 19.2 m (63 ft) long vacuum chamber at NASA Lewis Research Center is described. The chamber utilizes oil diffusion pumps in combination with cryopanels to achieve high vacuum pumping speeds at high vacuum levels. The facility is computer controlled for all phases of operation from start-up, through testing, to shutdown. The computer control system increases the utilization of the facility and reduces the manpower requirements needed for facility operations.

Shielding Effectiveness in a Two-Dimensional Reverberation Chamber Using Finite-Element Techniques

NASA Technical Reports Server (NTRS)

Bunting, Charles F.

2006-01-01

Reverberation chambers are attaining an increased importance in determination of electromagnetic susceptibility of avionics equipment. Given the nature of the variable boundary condition, the ability of a given source to couple energy into certain modes and the passband characteristic due the chamber Q, the fields are typically characterized by statistical means. The emphasis of this work is to apply finite-element techniques at cutoff to the analysis of a two-dimensional structure to examine the notion of shielding-effectiveness issues in a reverberating environment. Simulated mechanical stirring will be used to obtain the appropriate statistical field distribution. The shielding effectiveness (SE) in a simulated reverberating environment is compared to measurements in a reverberation chamber. A log-normal distribution for the SE is observed with implications for system designers. The work is intended to provide further refinement in the consideration of SE in a complex electromagnetic environment.

Induced Pluripotent Stem Cell Derived Mesenchymal Stem Cells for Attenuating Age-Related Bone Loss

DTIC Science & Technology

2012-07-01

Mesenchymal stem cell (MSC) differentiation towards the bone forming osteoblastic lineage decreases as a function of age and may contribute to age-related...problem of age-related reduced availability of MSC we propose to examine the bone anabolic potential of induced pluripotent stem cell (iPS) derived MSC

Dr. Gilruth and Dr. Kraft - Mission Control Center (MCC) - Apollo V Launch - MSC

NASA Image and Video Library

1968-01-22

S68-18733 (22 Jan. 1968) --- Dr. Robert R. Gilruth (right), MSC Director, sits with Dr. Christopher C. Kraft Jr., MSC director of flight operations, at his flight operations director console in the Mission Control Center, Building 30, during the Apollo 5 (LM-1/Saturn 204) unmanned space mission.

76 FR 35480 - Notice of Intent To Grant Partially Exclusive License

Federal Register 2010, 2011, 2012, 2013, 2014

2011-06-17

..., Endothelium Preserving Microwave Treatment For Atherosclerosis, NASA Case No. MSC- 22724-1, USPN 6,226,553, Endothelium Preserving Microwave Treatment For Atherosclerosis, NASA Case No. MSC-22724-2, USPN 6,223,086, Endothelium Preserving Microwave Treatment For Atherosclerosis, NASA Case No. MSC- 22724-3, and USPN 6,496,736...

Bi-directional activation between mesenchymal stem cells and CLL B-cells: implication for CLL disease progression.

PubMed

Ding, Wei; Nowakowski, Grzegorz S; Knox, Traci R; Boysen, Justin C; Maas, Mary L; Schwager, Susan M; Wu, Wenting; Wellik, Linda E; Dietz, Allan B; Ghosh, Asish K; Secreto, Charla R; Medina, Kay L; Shanafelt, Tait D; Zent, Clive S; Call, Timothy G; Kay, Neil E

2009-11-01

It was hypothesized that contact between chronic lymphocytic leukaemia (CLL) B-cells and marrow stromal cells impact both cell types. To test this hypothesis, we utilized a long-term primary culture system from bone biopsies that reliably generates a mesenchymal stem cell (MSC). Co-culture of MSC with CLL B-cells protected the latter from both spontaneous apoptosis and drug-induced apoptosis. The CD38 expression in previously CD38 positive CLL B-cells was up-regulated with MSC co-culture. Upregulation of CD71, CD25, CD69 and CD70 in CLL B-cells was found in the co-culture. CD71 upregulation was more significantly associated with high-risk CLL, implicating CD71 regulation in the microenvironment predicting disease progression. In MSC, rapid ERK and AKT phosphorylation (within 30 min) were detected when CLL B-cells and MSC were separated by transwell; indicating that activation of MSC was mediated by soluble factors. These findings support a bi-directional activation between bone marrow stromal cells and CLL B-cells.

Intramyocardial injection of autologous bone marrow-derived ex vivo expanded mesenchymal stem cells in acute myocardial infarction patients is feasible and safe up to 5 years of follow-up.

PubMed

Rodrigo, Sander F; van Ramshorst, Jan; Hoogslag, Georgette E; Boden, Helèn; Velders, Matthijs A; Cannegieter, Suzanne C; Roelofs, Helene; Al Younis, Imad; Dibbets-Schneider, Petra; Fibbe, Willem E; Zwaginga, Jaap Jan; Bax, Jeroen J; Schalij, Martin J; Beeres, Saskia L; Atsma, Douwe E

2013-10-01

In experimental studies, mesenchymal stem cell (MSC) transplantation in acute myocardial infarction (AMI) models has been associated with enhanced neovascularization and myogenesis. Clinical data however, are scarce. Therefore, the present study evaluates the safety and feasibility of intramyocardial MSC injection in nine patients, shortly after AMI during short-term and 5-year follow-up. Periprocedural safety analysis demonstrated one transient ischemic attack. No other adverse events related to MSC treatment were observed during 5-year follow-up. Clinical events were compared to a nonrandomized control group comprising 45 matched controls. A 5-year event-free survival after MSC-treatment was comparable to controls (89 vs. 91 %, P = 0.87). Echocardiographic imaging for evaluation of left ventricular function demonstrated improvements up to 5 years after MSC treatment. These findings were not significantly different when compared to controls. The present safety and feasibility study suggest that intramyocardial injection of MSC in patients shortly after AMI is feasible and safe up to 5-year follow-up.

Adaptation of MSC/NASTRAN to a supercomputer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gloudeman, J.F.; Hodge, J.C.

1982-01-01

MSC/NASTRAN is a large-scale general purpose digital computer program which solves a wider variety of engineering analysis problems by the finite element method. The program capabilities include static and dynamic structural analysis (linear and nonlinear), heat transfer, acoustics, electromagnetism and other types of field problems. It is used worldwide by large and small companies in such diverse fields as automotive, aerospace, civil engineering, shipbuilding, offshore oil, industrial equipment, chemical engineering, biomedical research, optics and government research. The paper presents the significant aspects of the adaptation of MSC/NASTRAN to the Cray-1. First, the general architecture and predominant functional use of MSC/NASTRANmore » are discussed to help explain the imperatives and the challenges of this undertaking. The key characteristics of the Cray-1 which influenced the decision to undertake this effort are then reviewed to help identify performance targets. An overview of the MSC/NASTRAN adaptation effort is then given to help define the scope of the project. Finally, some measures of MSC/NASTRAN's operational performance on the Cray-1 are given, along with a few guidelines to help avoid improper interpretation. 17 references.« less

The effects of axial displacement on fracture callus morphology and MSC homing depend on the timing of application.

PubMed

Weaver, Aaron S; Su, Yu-Ping; Begun, Dana L; Miller, Joshua D; Alford, Andrea I; Goldstein, Steven A

2010-07-01

The local mechanical environment and the availability of mesenchymal stem cells (MSC) have both been shown to be important factors in bone fracture healing. This study was designed to investigate how the timing of an applied axial displacement across a healing fracture affects callus properties as well as the migration of systemically introduced MSC. Bilateral osteotomies were created in male, Sprague-Dawley rats. Exogenous MSC were injected via the tail vein, and a controlled micro-motion was applied to one defect starting 0, 3, 10, or 24 days after surgery. The results showed that fractures stimulated 10 days after surgery had more mineral, less cartilage, and greater mechanical properties at 48 days than other groups. Populations of MSC were found in osteotomies 48 days after surgery, with the exception of the group that was stimulated 10 days after surgery. These results demonstrate that the timing of mechanical stimulation affects the physical properties of the callus and the migration of MSC to the fracture site. Published by Elsevier Inc.

Quantitative ionization chamber alignment to a water surface: Theory and simulation.

PubMed

Siebers, Jeffrey V; Ververs, James D; Tessier, Frédéric

2017-07-01

To examine the response properties of cylindrical cavity ionization chambers (ICs) in the depth-ionization buildup region so as to obtain a robust chamber-signal - based method for definitive water surface identification, hence absolute ionization chamber depth localization. An analytical model with simplistic physics and geometry is developed to explore the theoretical aspects of ionization chamber response near a phantom water surface. Monte Carlo simulations with full physics and ionization chamber geometry are utilized to extend the model's findings to realistic ion chambers in realistic beams and to study the effects of IC design parameters on the entrance dose response. Design parameters studied include full and simplified IC designs with varying central electrode thickness, wall thickness, and outer chamber radius. Piecewise continuous fits to the depth-ionization signal gradient are used to quantify potential deviation of the gradient discontinuity from the chamber outer radius. Exponential, power, and hyperbolic sine functional forms are used to model the gradient for chamber depths of zero to the depth of the gradient discontinuity. The depth-ionization gradient as a function of depth is maximized and discontinuous when a submerged IC's outer radius coincides with the water surface. We term this depth the gradient chamber alignment point (gCAP). The maximum deviation between the gCAP location and the chamber outer radius is 0.13 mm for a hypothetical 4 mm thick wall, 6.45 mm outer radius chamber using the power function fit, however, the chamber outer radius is within the 95% confidence interval of the gCAP determined by this fit. gCAP dependence on the chamber wall thickness is possible, but not at a clinically relevant level. The depth-ionization gradient has a discontinuity and is maximized when the outer-radius of a submerged IC coincides with the water surface. This feature can be used to auto-align ICs to the water surface at the time of scanning and/or be applied retrospectively to scan data to quantify absolute IC depth. Utilization of the gCAP should yield accurate and reproducible depth calibration for clinical depth-ionization measurements between setups and between users. © 2017 American Association of Physicists in Medicine.

Response of the first wetted wall of an IFE reactor chamber to the energy release from a direct-drive DT capsule

DOE Office of Scientific and Technical Information (OSTI.GOV)

Medin, Stanislav A.; Basko, Mikhail M.; Orlov, Yurii N.

2012-07-11

Radiation hydrodynamics 1D simulations were performed with two concurrent codes, DEIRA and RAMPHY. The DEIRA code was used for DT capsule implosion and burn, and the RAMPHY code was used for computation of X-ray and fast ions deposition in the first wall liquid film of the reactor chamber. The simulations were run for 740 MJ direct drive DT capsule and Pb thin liquid wall reactor chamber of 10 m diameter. Temporal profiles for DT capsule leaking power of X-rays, neutrons and fast {sup 4}He ions were obtained and spatial profiles of the liquid film flow parameter were computed and analyzed.

From diffusion pumps to cryopumps: The conversion of GSFC's space environment simulator

NASA Technical Reports Server (NTRS)

Cary, Ron

1992-01-01

The SES (Space Environmental Simulator), largest of the Thermal Vacuum Facilities at The Goddard Space Flight Center, recently was converted from an oil diffusion pumped chamber to a Cryopumped chamber. This modification was driven by requirements of flight projects. The basic requirement was to retain or enhance the operational parameters of the chamber such as pumping speed, ultimate vacuum, pump down time, and thermal system performance. To accomplish this task, seventeen diffusion pumps were removed and replaced with eight 1.2 meter (48 inch) diameter cryopumps and one 0.5 meter (20 inch) turbomolecular pump. The conversion was accomplished with a combination of subcontracting and in-house efforts to maximize the efficiency of implementation.

Effect of trichlorofluoromethane and molecular chlorine on ozone formation by simulated solar radiation

NASA Technical Reports Server (NTRS)

Bittker, D. A.; Wong, E. L.

1977-01-01

Mixtures of air with either Cl2 or CFCl3 were photolyzed in a reaction chamber by simulated solar radiation. Ozone formation was temporarily inhibited by Cl2 and permanently inhibited by CFCl3. A chemical mechanism including gas phase and wall reactions is proposed to explain these results. The CFCl3 is assumed to be adsorbed on the chamber walls and to poison the sites for Cl destruction.

Dosimetry in MARS spectral CT: TOPAS Monte Carlo simulations and ion chamber measurements.

PubMed

Lu, Gray; Marsh, Steven; Damet, Jerome; Carbonez, Pierre; Laban, John; Bateman, Christopher; Butler, Anthony; Butler, Phil

2017-06-01

Spectral computed tomography (CT) is an up and coming imaging modality which shows great promise in revealing unique diagnostic information. Because this imaging modality is based on X-ray CT, it is of utmost importance to study the radiation dose aspects of its use. This study reports on the implementation and evaluation of a Monte Carlo simulation tool using TOPAS for estimating dose in a pre-clinical spectral CT scanner known as the MARS scanner. Simulated estimates were compared with measurements from an ionization chamber. For a typical MARS scan, TOPAS estimated for a 30 mm diameter cylindrical phantom a CT dose index (CTDI) of 29.7 mGy; CTDI was measured by ion chamber to within 3% of TOPAS estimates. Although further development is required, our investigation of TOPAS for estimating MARS scan dosimetry has shown its potential for further study of spectral scanning protocols and dose to scanned objects.

Multi-injector modeling of transverse combustion instability experiments

NASA Astrophysics Data System (ADS)

Shipley, Kevin J.

Concurrent simulations and experiments are used to study combustion instabilities in a multiple injector element combustion chamber. The experiments employ a linear array of seven coaxial injector elements positioned atop a rectangular chamber. Different levels of instability are driven in the combustor by varying the operating and geometry parameters of the outer driving injector elements located near the chamber end-walls. The objectives of the study are to apply a reduced three-injector model to generate a computational test bed for the evaluation of injector response to transverse instability, to apply a full seven-injector model to investigate the inter-element coupling between injectors in response to transverse instability, and to further develop this integrated approach as a key element in a predictive methodology that relies heavily on subscale test and simulation. To measure the effects of the transverse wave on a central study injector element two opposing windows are placed in the chamber to allow optical access. The chamber is extensively instrumented with high-frequency pressure transducers. High-fidelity computational fluid dynamics simulations are used to model the experiment. Specifically three-dimensional, detached eddy simulations (DES) are used. Two computational approaches are investigated. The first approach models the combustor with three center injectors and forces transverse waves in the chamber with a wall velocity function at the chamber side walls. Different levels of pressure oscillation amplitudes are possible by varying the amplitude of the forcing function. The purpose of this method is to focus on the combustion response of the study element. In the second approach, all seven injectors are modeled and self-excited combustion instability is achieved. This realistic model of the chamber allows the study of inter-element flow dynamics, e.g., how the resonant motions in the injector tubes are coupled through the transverse pressure waves in the chamber. The computational results are analyzed and compared with experiment results in the time, frequency and modal domains. Results from the three injector model show how applying different velocity forcing amplitudes change the amplitude and spatial location of heat release from the center injector. The instability amplitudes in the simulation are able to be tuned to experiments and produce similar modal combustion responses of the center injector. The reaction model applied was found to play an important role in the spatial and temporal heat release response. Only when the model was calibrated to ignition delay measurements did the heat release response reflect measurements in the experiment. While insightful the simulations are not truly predictive because the driving frequency and forcing function amplitude are input into the simulation. However, the use of this approach as a tool to investigate combustion response is demonstrated. Results from the seven injector simulations provide an insightful look at the mechanisms driving the instability in the combustor. The instability was studied over a range of pressure fluctuations, up to 70% of mean chamber pressure produced in the self-exited simulation. At low amplitudes the transverse instability was found to be supported by both flame impingement with the side wall as well as vortex shedding at the primary acoustic frequency. As instability level grew the primary supporting mechanism shifted to just vortex impingement on the side walls and the greatest growth was seen as additional vortices began impinging between injector elements at the primary acoustic frequency. This research reveals the advantages and limitations of applying these two modeling techniques to simulate multiple injector experiments. The advantage of the three injector model is a simplified geometry which results in faster model development and the ability to more rapidly study the injector response under varying velocity amplitudes. The possibly faster run time is offset though by the need to run multiple cases to calibrate the model to the experiment. The model is also limited to studying the central injector effect and lacks heat release sources from the outer injectors and additional vortex interactions as shown in the seven injector simulation. The advantage of the seven injector model is that the whole domain can be explored to provide a better understanding about influential processes but does require longer development and run time due to the extensive gridding requirement. Both simulations have proven useful in exploring transverse combustion instability and show the need to further develop subscale experiments and companions simulations in developing a full-scale combustion instability prediction capability.

26th Space Simulation Conference Proceedings. Environmental Testing: The Path Forward

NASA Technical Reports Server (NTRS)

Packard, Edward A.

2010-01-01

Topics covered include: A Multifunctional Space Environment Simulation Facility for Accelerated Spacecraft Materials Testing; Exposure of Spacecraft Surface Coatings in a Simulated GEO Radiation Environment; Gravity-Offloading System for Large-Displacement Ground Testing of Spacecraft Mechanisms; Microscopic Shutters Controlled by cRIO in Sounding Rocket; Application of a Physics-Based Stabilization Criterion to Flight System Thermal Testing; Upgrade of a Thermal Vacuum Chamber for 20 Kelvin Operations; A New Approach to Improve the Uniformity of Solar Simulator; A Perfect Space Simulation Storm; A Planetary Environmental Simulator/Test Facility; Collimation Mirror Segment Refurbishment inside ESA s Large Space; Space Simulation of the CBERS 3 and 4 Satellite Thermal Model in the New Brazilian 6x8m Thermal Vacuum Chamber; The Certification of Environmental Chambers for Testing Flight Hardware; Space Systems Environmental Test Facility Database (SSETFD), Website Development Status; Wallops Flight Facility: Current and Future Test Capabilities for Suborbital and Orbital Projects; Force Limited Vibration Testing of JWST NIRSpec Instrument Using Strain Gages; Investigation of Acoustic Field Uniformity in Direct Field Acoustic Testing; Recent Developments in Direct Field Acoustic Testing; Assembly, Integration and Test Centre in Malaysia: Integration between Building Construction Works and Equipment Installation; Complex Ground Support Equipment for Satellite Thermal Vacuum Test; Effect of Charging Electron Exposure on 1064nm Transmission through Bare Sapphire Optics and SiO2 over HfO2 AR-Coated Sapphire Optics; Environmental Testing Activities and Capabilities for Turkish Space Industry; Integrated Circuit Reliability Simulation in Space Environments; Micrometeoroid Impacts and Optical Scatter in Space Environment; Overcoming Unintended Consequences of Ambient Pressure Thermal Cycling Environmental Tests; Performance and Functionality Improvements to Next Generation Thermal Vacuum Control System; Robotic Lunar Lander Development Project: Three-Dimensional Dynamic Stability Testing and Analysis; Thermal Physical Properties of Thermal Coatings for Spacecraft in Wide Range of Environmental Conditions: Experimental and Theoretical Study; Molecular Contamination Generated in Thermal Vacuum Chambers; Preventing Cross Contamination of Hardware in Thermal Vacuum Chambers; Towards Validation of Particulate Transport Code; Updated Trends in Materials' Outgassing Technology; Electrical Power and Data Acquisition Setup for the CBER 3 and 4 Satellite TBT; Method of Obtaining High Resolution Intrinsic Wire Boom Damping Parameters for Multi-Body Dynamics Simulations; and Thermal Vacuum Testing with Scalable Software Developed In-House.

Preclinical Biosafety Evaluation of Genetically Modified Human Adipose Tissue-Derived Mesenchymal Stem Cells for Clinical Applications to Brainstem Glioma.

PubMed

Choi, Seung Ah; Yun, Jun-Won; Joo, Kyeung Min; Lee, Ji Yeoun; Kwak, Pil Ae; Lee, Young Eun; You, Ji-Ran; Kwon, Euna; Kim, Woo Ho; Wang, Kyu-Chang; Phi, Ji Hoon; Kang, Byeong-Cheol; Kim, Seung-Ki

2016-06-15

Stem-cell based gene therapy is a promising novel therapeutic approach for inoperable invasive tumors, including brainstem glioma. Previously, we demonstrated the therapeutic potential of human adipose tissue-derived mesenchymal stem cells (hAT-MSC) genetically engineered to express a secreted form of tumor necrosis factor-related apoptosis-inducing ligand (sTRAIL) against brainstem glioma. However, safety concerns should be comprehensively investigated before clinical applications of hAT-MSC.sTRAIL. At first, we injected stereotactically low (1.2 × 10(5) cells/18 μL), medium (2.4 × 10(5)/18 μL), or high dose (3.6 × 10(5)/18 μL) of hAT-MSC.sTRAIL into the brainstems of immunodeficient mice reflecting the plan of the future clinical trial. Local toxicity, systemic toxicity, secondary tumor formation, and biodistribution of hAT-MSC.sTRAIL were investigated. Next, presence of hAT-MSC.sTRAIL was confirmed in the brain and major organs at 4, 9, and 14 weeks in brainstem glioma-bearing mice. In the 15-week subchronic toxicity test, no serious adverse events in terms of body weight, food consumption, clinical symptom, urinalysis, hematology, clinical chemistry, organ weight, and histopathology were observed. In the 26-week tumorigenicity test, hAT-MSC.sTRAIL made no detectable tumors, whereas positive control U-87 MG cells made huge tumors in the brainstem. No remaining hAT-MSC.sTRAIL was observed in any organs examined, including the brainstem at 15 or 26 weeks. In brainstem glioma-bearing mice, injected hAT-MSC.sTRAIL was observed, but gradually decreased over time in the brain. The mRNA of human specific GAPDH and TRAIL was not detected in all major organs. These results indicate that the hAT-MSC.sTRAIL could be applicable to the future clinical trials in terms of biosafety.

Intranasally administered mesenchymal stem cells promote a regenerative niche for repair of neonatal ischemic brain injury.

PubMed

Donega, Vanessa; Nijboer, Cora H; van Tilborg, Geralda; Dijkhuizen, Rick M; Kavelaars, Annemieke; Heijnen, Cobi J

2014-11-01

Previous work from our group has shown that intranasal MSC-treatment decreases lesion volume and improves motor and cognitive behavior after hypoxic-ischemic (HI) brain damage in neonatal mice. Our aim was to determine the kinetics of MSC migration after intranasal administration, and the early effects of MSCs on neurogenic processes and gliosis at the lesion site. HI brain injury was induced in 9-day-old mice and MSCs were administered intranasally at 10days post-HI. The kinetics of MSC migration were investigated by immunofluorescence and MRI analysis. BDNF and NGF gene expression was determined by qPCR analysis following MSC co-culture with HI brain extract. Nestin, Doublecortin, NeuN, GFAP, Iba-1 and M1/M2 phenotypic expression was assessed over time. MRI and immunohistochemistry analyses showed that MSCs reach the lesion site already within 2h after intranasal administration. At 12h after administration the number of MSCs at the lesion site peaks and decreases significantly at 72h. The number of DCX(+) cells increased 1 to 3days after MSC administration in the SVZ. At the lesion, GFAP(+)/nestin(+) and DCX(+) expression increased 3 to 5days after MSC-treatment. The number of NeuN(+) cells increased within 5days, leading to a dramatic regeneration of the somatosensory cortex and hippocampus at 18days after intranasal MSC administration. Interestingly, MSCs expressed significantly more BDNF gene when exposed to HI brain extract in vitro. Furthermore, MSC-treatment resulted in the resolution of the glial scar surrounding the lesion, represented by a decrease in reactive astrocytes and microglia and polarization of microglia towards the M2 phenotype. In view of the current lack of therapeutic strategies, we propose that intranasal MSC administration is a powerful therapeutic option through its functional repair of the lesion represented by regeneration of the cortical and hippocampal structure and decrease of gliosis. Copyright © 2014. Published by Elsevier Inc.

An MSC2 Promoter-lacZ Fusion Gene Reveals Zinc-Responsive Changes in Sites of Transcription Initiation That Occur across the Yeast Genome

PubMed Central

Wu, Yi-Hsuan; Taggart, Janet; Song, Pamela Xiyao; MacDiarmid, Colin; Eide, David J.

2016-01-01

The Msc2 and Zrg17 proteins of Saccharomyces cerevisiae form a complex to transport zinc into the endoplasmic reticulum. ZRG17 is transcriptionally induced in zinc-limited cells by the Zap1 transcription factor. In this report, we show that MSC2 mRNA also increases (~1.5 fold) in zinc-limited cells. The MSC2 gene has two in-frame ATG codons at its 5’ end, ATG1 and ATG2; ATG2 is the predicted initiation codon. When the MSC2 promoter was fused at ATG2 to the lacZ gene, we found that unlike the chromosomal gene this reporter showed a 4-fold decrease in lacZ mRNA in zinc-limited cells. Surprisingly, β-galactosidase activity generated by this fusion gene increased ~7 fold during zinc deficiency suggesting the influence of post-transcriptional factors. Transcription of MSC2ATG2-lacZ was found to start upstream of ATG1 in zinc-replete cells. In zinc-limited cells, transcription initiation shifted to sites just upstream of ATG2. From the results of mutational and polysome profile analyses, we propose the following explanation for these effects. In zinc-replete cells, MSC2ATG2-lacZ mRNA with long 5’ UTRs fold into secondary structures that inhibit translation. In zinc-limited cells, transcripts with shorter unstructured 5’ UTRs are generated that are more efficiently translated. Surprisingly, chromosomal MSC2 did not show start site shifts in response to zinc status and only shorter 5’ UTRs were observed. However, the shifts that occur in the MSC2ATG2-lacZ construct led us to identify significant transcription start site changes affecting the expression of ~3% of all genes. Therefore, zinc status can profoundly alter transcription initiation across the yeast genome. PMID:27657924

Role of SDF‐1:CXCR4 in Impaired Post‐Myocardial Infarction Cardiac Repair in Diabetes

PubMed Central

Mayorga, Maritza E.; Kiedrowski, Matthew; McCallinhart, Patricia; Forudi, Farhad; Ockunzzi, Jeremiah; Weber, Kristal; Chilian, William; Penn, Marc S.

2017-01-01

Abstract Diabetes is a risk factor for worse outcomes following acute myocardial infarction (AMI). In this study, we tested the hypothesis that SDF‐1:CXCR4 expression is compromised in post‐AMI in diabetes, and that reversal of this defect can reverse the adverse effects of diabetes. Mesenchymal stem cells (MSC) isolated from green fluorescent protein (GFP) transgenic mice (control MSC) were induced to overexpress stromal cell‐derived factor‐1 (SDF‐1). SDF‐1 expression in control MSC and SDF‐1‐overexpressing MSC (SDF‐1:MSC) were quantified using enzyme‐linked immunosorbent assay (ELISA). AMI was induced on db/db and control mice. Mice were randomly selected to receive infusion of control MSC, SDF‐1:MSC, or saline into the border zone after AMI. Serial echocardiography was used to assess cardiac function. SDF‐1 and CXCR4 mRNA expression in the infarct zone of db/db mice and control mice were quantified. Compared to control mice, SDF‐1 levels were decreased 82%, 91%, and 45% at baseline, 1 day and 3 days post‐AMI in db/db mice, respectively. CXCR4 levels are increased 233% at baseline and 54% 5 days post‐AMI in db/db mice. Administration of control MSC led to a significant improvement in ejection fraction (EF) in control mice but not in db/db mice 21 days after AMI. In contrast, administration of SDF‐1:MSC produced a significant improvement in EF in both control mice and db/db mice 21 days after AMI. The SDF‐1:CXCR4 axis is compromised in diabetes, which appears to augment the deleterious consequences of AMI. Over‐express of SDF‐1 expression in diabetes rescues cardiac function post AMI. Our results suggest that modulation of SDF‐1 may improve post‐AMI cardiac repair in diabetes. stem cells translational medicine 2018;7:115–124 PMID:29119710

Biologic injections for osteoarthritis and articular cartilage damage: can we modify disease?

PubMed

Shi, Weilong J; Tjoumakaris, Fotios P; Lendner, Mayan; Freedman, Kevin B

2017-09-01

The purpose of the present investigation is to conduct a systematic review of the literature to review the clinical results of platelet rich plasma (PRP) and mesenchymal stem cell treatments (MSC) (biologics) for articular cartilage lesions and osteoarthritis of the knee. A search of the PubMed, EMBASE, and Cochrane databases was performed to identify studies involving biologic therapy for osteoarthritis or osteochondral defects. Only Level I-III clinical trials with at least 3-month follow-up were included. Outcome data was gathered on any patient-completed surveys, 2nd look arthroscopy, follow-up imaging, biopsy/histology results, and any adverse effects of treatment. Thirty-three articles met our inclusion criteria. There was a total of 21 PRP studies in the study. All PRP studies showed clinical improvement with PRP therapies in outcomes surveys measuring patient satisfaction, pain, and function. Two studies reported no significant difference in improvement compared to hyaluronic acid (HA). Similarly, the 7/9 MSC studies showed improvement. One study found BM-MSC implantation was not significantly superior to matrix assisted chondrocyte implantation (MACI), while one reported peripheral blood stem cells (PBSC) did not significantly improve outcomes over HA. Of the three studies looking at a combination of MSC/PRP, two found MSC/PRP combination did not improve outcomes compared to MSC or PRP therapy alone. The one PRP study that had a 2nd look arthroscopy reported increases cartilage regeneration with PRP. All 8 MSC studies with follow-up MRI and all 7 MSC studies with 2nd look arthroscopy showed improvement in cartilage regeneration in terms of coverage, fill of the defect, and/or firmness of the new cartilage. Current data suggests that, of the two treatments, MSC provides more significant disease modifying effect; however, further research needs to be done to compare these two treatments and determine if there is a synergetic effect when combined.

An investigation of air inlet velocity in simulating the dispersion of indoor contaminants via computational fluid dynamics.

PubMed

Lee, Eungyoung; Feigley, Charles E; Khan, Jamil

2002-11-01

Computational fluid dynamics (CFD) is potentially a valuable tool for simulating the dispersion of air contaminants in workrooms. However, CFD-estimated airflow and contaminant concentration patterns have not always shown good agreement with experimental results. Thus, understanding the factors affecting the accuracy of such simulations is critical for their successful application in occupational hygiene. The purposes of this study were to validate CFD approaches for simulating the dispersion of gases and vapors in an enclosed space at two air flow rates and to demonstrate the impact of one important determinant of simulation accuracy. The concentration of a tracer gas, isobutylene, was measured at 117 points in a rectangular chamber [1 (L) x 0.3 (H) x 0.7 m (W)] using a photoionization analyzer. Chamber air flow rates were scaled using geometric and kinematic similarity criteria to represent a full-sized room at two Reynolds numbers (Re = 5 x 10(2) and 5 x 10(3)). Also, CFD simulations were conducted to estimate tracer gas concentrations throughout the chamber. The simulation results for two treatments of air inlet velocity (profiled inlet velocity measured in traverses across the air inlet and the assumption that air velocity is uniform across the inlet) were compared with experimental observations. The CFD-simulated 3-dimensional distribution of tracer gas concentration using the profiled inlet velocity showed better agreement qualitatively and quantitatively with measured chamber concentration, while the concentration estimated using the uniform inlet velocity showed poor agreement for both comparisons. For estimating room air contaminant concentrations when inlet velocities can be determined, this study suggests that using the inlet velocity distribution to define inlet boundary conditions for CFD simulations can provide more reliable estimates. When the inlet velocity distribution is not known, for instance for prospective design of dilution ventilation systems, the trials of several velocity profiles with different source, air inlet and air outlet locations may be useful for determining the most efficient workroom layout.

CFD simulation of coaxial injectors

NASA Technical Reports Server (NTRS)

Landrum, D. Brian

1993-01-01

The development of improved performance models for the Space Shuttle Main Engine (SSME) is an important, ongoing program at NASA MSFC. These models allow prediction of overall system performance, as well as analysis of run-time anomalies which might adversely affect engine performance or safety. Due to the complexity of the flow fields associated with the SSME, NASA has increasingly turned to Computational Fluid Dynamics (CFD) techniques as modeling tools. An important component of the SSME system is the fuel preburner, which consists of a cylindrical chamber with a plate containing 264 coaxial injector elements at one end. A fuel rich mixture of gaseous hydrogen and liquid oxygen is injected and combusted in the chamber. This process preheats the hydrogen fuel before it enters the main combustion chamber, powers the hydrogen turbo-pump, and provides a heat dump for nozzle cooling. Issues of interest include the temperature and pressure fields at the turbine inlet and the thermal compatibility between the preburner chamber and injector plate. Performance anomalies can occur due to incomplete combustion, blocked injector ports, etc. The performance model should include the capability to simulate the effects of these anomalies. The current approach to the numerical simulation of the SSME fuel preburner flow field is to use a global model based on the MSFC sponsored FNDS code. This code does not have the capabilities of modeling several aspects of the problem such as detailed modeling of the coaxial injectors. Therefore, an effort has been initiated to develop a detailed simulation of the preburner coaxial injectors and provide gas phase boundary conditions just downstream of the injector face as input to the FDNS code. This simulation should include three-dimensional geometric effects such as proximity of injectors to baffles and chamber walls and interaction between injectors. This report describes an investigation into the numerical simulation of GH2/LOX coaxial injectors. The following sections will discuss the physical aspects of injectors, the CFD code employed, and preliminary results of a simulation of a single coaxial injector for which experimental data is available. It is hoped that this work will lay the foundation for the development of a unique and useful tool to support the SSME program.

Modelling the effect of diffuse light on canopy photosynthesis in controlled environments

NASA Technical Reports Server (NTRS)

Cavazzoni, James; Volk, Tyler; Tubiello, Francesco; Monje, Oscar; Janes, H. W. (Principal Investigator)

2002-01-01

A layered canopy model was used to analyze the effects of diffuse light on canopy gross photosynthesis in controlled environment plant growth chambers, where, in contrast to the field, highly diffuse light can occur at high irradiance. The model suggests that high diffuse light fractions (approximately 0.7) and irradiance (1400 micromoles m-2 s-1) may enhance crop life-cycle canopy gross photosynthesis for hydroponic wheat by about 20% compared to direct light at the same irradiance. Our simulations suggest that high accuracy is not needed in specifying diffuse light fractions in chambers between approximately 0.7 and 1, because simulated photosynthesis for closed canopies plateau in this range. We also examined the effect of leaf angle distribution on canopy photosynthesis under growth chamber conditions, as these distributions determine canopy extinction coefficients for direct and diffuse light. We show that the spherical leaf angle distribution is not suitable for modeling photosynthesis of planophile canopies (e.g., soybean and peanut) in growth chambers. Also, the absorption of the light reflected from the surface below the canopy should generally be included in model simulations, as the corresponding albedo values in the photosynthetically active range may be quite high in growth chambers (e.g., approximately 0.5). In addition to the modeling implications, our results suggest that diffuse light conditions should be considered when drawing conclusions from experiments in controlled environments.

Technical Note: Intercomparison of formaldehyde measurements at the atmosphere simulation chamber SAPHIR

NASA Astrophysics Data System (ADS)

Wisthaler, A.; Apel, E. C.; Bossmeyer, J.; Hansel, A.; Junkermann, W.; Koppmann, R.; Meier, R.; Müller, K.; Solomon, S. J.; Steinbrecher, R.; Tillmann, R.; Brauers, T.

2008-04-01

The atmosphere simulation chamber SAPHIR at the Research Centre Jülich was used to test the suitability of state-of-the-art analytical instruments for the measurement of gas-phase formaldehyde (HCHO) in air. Five analyzers based on four different sensing principles were deployed: a differential optical absorption spectrometer (DOAS), cartridges for 2,4-dinitrophenylhydrazine (DNPH) derivatization followed by off-line high pressure liquid chromatography (HPLC) analysis, two different types of commercially available wet chemical sensors based on Hantzsch fluorimetry, and a proton-transfer-reaction mass spectrometer (PTR-MS). A new optimized mode of operation was used for the PTR-MS instrument which significantly enhanced its performance for online HCHO detection at low absolute humidities. The instruments were challenged with typical ambient levels of HCHO ranging from zero to several ppb. Synthetic air of high purity and particulate-filtered ambient air were used as sample matrices in the atmosphere simulation chamber onto which HCHO was spiked under varying levels of humidity and ozone. Measurements were compared to mixing ratios calculated from the chamber volume and the known amount of HCHO injected into the chamber; measurements were also compared between the different instruments. The formal and blind intercomparison exercise was conducted under the control of an independent referee. A number of analytical problems associated with the experimental set-up and with individual instruments were identified, the overall agreement between the methods was fair.

Mesenchymal Stem Cells Stabilize Atherosclerotic Vulnerable Plaque by Anti-Inflammatory Properties

PubMed Central

Wang, Shuang-shuang; Hu, Si-wang; Zhang, Qing-hua; Xia, Ai-xiang

2015-01-01

Background and objectives Formation and progression of atherosclerotic vulnerable plaque (VP) is the primary cause of many cardio-cerebrovascular diseases such as acute coronary syndrome and stroke. It has been reported that bone marrow mesenchymal stem cells (MSC) exhibit protective effects against many kinds of diseases including myocardial infarction. Here, we examined the effects of intravenous MSC infusion on a VP model and provide novel evidence of its influence as a therapy in this animal disease model. Subjects and methods Thirty healthy male New Zealand white rabbits were randomly divided into a MSC, VP or stable plaque (SP) group (n = 10/group) and received high fat diet and cold-induced common carotid artery intimal injury with liquid nitrogen to form atherosclerotic plaques. Serum hs-CRP, TNF-α, IL-6 and IL-10 levels were measured by ELISA at 1, 2, 3, 7, 14, 21 and 28 days after MSC transplantation. The animals were sacrificed at 4 weeks after MSC transplantation. Lesions in the right common carotid were observed using H&E and Masson staining, and the fibrous cap/lipid core ratio of atherosclerotic plaques were calculated. The expression of nuclear factor κB (NF-κB) and matrix metalloproteinase 1, 2, 9 (MMP-1,2,9) in the plaque were detected using immunohistochemistry, and apoptotic cells in the plaques were detected by TUNEL. In addition, the level of TNF-α stimulated gene/protein 6 (TSG-6) mRNA and protein were measured by quantitative Real-Time PCR and Western blotting, respectively. Results Two rabbits in the VP group died of lung infection and cerebral infarction respectively at 1 week after plaque injury by liquid nitrogen. Both H&E and Masson staining revealed that the plaques from the SP and MSC groups had more stable morphological structure and a larger fibrous cap/lipid core ratio than the VP group. Serum hs-CRP, TNF-α and IL-6 were significantly down-regulated, whereas IL-10 was significantly up-regulated in the MSC group compared with the VP group. .Immunohistochemistry analysis revealed that NF-κB and MMP expression was reduced in the MSC and SP groups compared to the VP group. Cell apoptosis decreased significantly in both the MSC and SP groups in comparison to the VP group. TSG-6 mRNA and protein expression were higher in the plaques of the MSC group compared to the VP and SP groups. Conclusions Our study results suggest that MSC transplantation can effectively stabilize vulnerable plaques in atherosclerotic rabbits. This may potentially offer a new clinical application of MSC in atherosclerosis. PMID:26288013

Human Mesenchymal Stem Cell Transfusion Is Safe and Improves Liver Function in Acute-on-Chronic Liver Failure Patients

PubMed Central

Shi, Ming; Zhang, Zheng; Xu, Ruonan; Lin, Hu; Fu, Junliang; Zou, Zhengsheng; Zhang, Aimin; Shi, Jianfei; Chen, Liming; Lv, Sa; He, Weiping; Geng, Hua; Jin, Lei; Liu, Zhenwen

2012-01-01

Acute-on-chronic liver failure (ACLF) is a severe, life-threatening complication, and new and efficient therapeutic strategies for liver failure are urgently needed. Mesenchymal stem cell (MSC) transfusions have been shown to reverse fulminant hepatic failure in mice and to improve liver function in patients with end-stage liver diseases. We assessed the safety and initial efficacy of umbilical cord-derived MSC (UC-MSC) transfusions for ACLF patients associated with hepatitis B virus (HBV) infection. A total of 43 ACLF patients were enrolled for this open-labeled and controlled study; 24 patients were treated with UC-MSCs, and 19 patients were treated with saline as controls. UC-MSC therapy was given three times at 4-week intervals. The liver function, adverse events, and survival rates were evaluated during the 48-week or 72-week follow-up period. No significant side effects were observed during the trial. The UC-MSC transfusions significantly increased the survival rates in ACLF patients; reduced the model for end-stage liver disease scores; increased serum albumin, cholinesterase, and prothrombin activity; and increased platelet counts. Serum total bilirubin and alanine aminotransferase levels were significantly decreased after the UC-MSC transfusions. UC-MSC transfusions are safe in the clinic and may serve as a novel therapeutic approach for HBV-associated ACLF patients. PMID:23197664

Therapeutic potential of mesenchymal stem cell transplantation in a nitrofen-induced congenital diaphragmatic hernia rat model.

PubMed

Yuniartha, Ratih; Alatas, Fatima Safira; Nagata, Kouji; Kuda, Masaaki; Yanagi, Yusuke; Esumi, Genshiro; Yamaza, Takayoshi; Kinoshita, Yoshiaki; Taguchi, Tomoaki

2014-09-01

The aim of this study was to evaluate the efficacy of mesenchymal stem cells (MSCs) in a nitrofen-induced congenital diaphragmatic hernia (CDH) rat model. Pregnant rats were exposed to nitrofen on embryonic day 9.5 (E9.5). MSCs were isolated from the enhanced green fluorescent protein (eGFP) transgenic rat lungs. The MSCs were transplanted into the nitrofen-induced E12.5 rats via the uterine vein, and the E21 lung explants were harvested. The study animals were divided into three: the control group, the nitrofen-induced left CDH (CDH group), and the MSC-treated nitrofen-induced left CDH (MSC-treated CDH group). The specimens were morphologically analyzed using HE and immunohistochemical staining with proliferating cell nuclear antigen (PCNA), surfactant protein-C (SP-C), and α-smooth muscle actin. The alveolar and medial walls of the pulmonary arteries were significantly thinner in the MSC-treated CDH group than in the CDH group. The alveolar air space areas were larger, while PCNA and the SP-C positive cells were significantly higher in the MSC-treated CDH group, than in the CDH group. MSC engraftment was identified on immunohistochemical staining of the GFP in the MSC-treated CDH group. MSC transplantation potentially promotes alveolar and pulmonary artery development, thereby reducing the severity of pulmonary hypoplasia.

Genetically modified mesenchymal stem cells (MSCs) promote axonal regeneration and prevent hypersensitivity after spinal cord injury.

PubMed

Kumagai, Gentaro; Tsoulfas, Pantelis; Toh, Satoshi; McNiece, Ian; Bramlett, Helen M; Dietrich, W Dalton

2013-10-01

Neurotrophins and the transplantation of bone marrow-derived stromal cells (MSCs) are both candidate therapies targeting spinal cord injury (SCI). While some studies have suggested the ability of MSCs to transdifferentiate into neural cells, other SCI studies have proposed anti-inflammatory and other mechanisms underlying established beneficial effects. We grafted rat MSCs genetically modified to express MNTS1, a multineurotrophin that binds TrkA, TrkB and TrkC, and p75(NTR) receptors or MSC-MNTS1/p75(-) that binds mainly to the Trk receptors. Seven days after contusive SCI, PBS-only, GFP-MSC, MSC-MNTS1/GFP or MSC-MNTS1/p75(-)/GFP were delivered into the injury epicenter. All transplanted groups showed reduced inflammation and cystic cavity size compared to control SCI rats. Interestingly, transplantation of the MSC-MNTS1 and MSC-MNTS1/p75(-), but not the naïve MSCs, enhanced axonal growth and significantly prevented cutaneous hypersensitivity after SCI. Moreover, transplantation of MSC-MNTS1/p75(-) promoted angiogenesis and modified glial scar formation. These findings suggest that MSCs transduced with a multineurotrophin are effective in promoting cell growth and improving sensory function after SCI. These novel data also provide insight into the neurotrophin-receptor dependent mechanisms through which cellular transplantation leads to functional improvement after experimental SCI. © 2013.

Additive effect of mesenchymal stem cells and defibrotide in an arterial rat thrombosis model.

PubMed

Dilli, Dilek; Kılıç, Emine; Yumuşak, Nihat; Beken, Serdar; Uçkan Çetinkaya, Duygu; Karabulut, Ramazan; Zenciroğlu, Ayşegu L

2017-06-01

In this study, we aimed to investigate the additive effect of mesenchymal stem cells (MSC) and defibrotide (DFT) in a rat model of femoral arterial thrombosis. Thirty Sprague Dawley rats were included. An arterial thrombosis model by ferric chloride (FeCl3) was developed in the left femoral artery. The rats were equally assigned to 5 groups: Group 1-Sham-operated (without arterial injury); Group 2-Phosphate buffered saline (PBS) injected; Group 3-MSC; Group 4-DFT; Group 5-MSC + DFT. All had two intraperitoneal injections of 0.5 ml: the 1st injection was 4 h after the procedure and the 2nd one 48 h after the 1st injection. The rats were sacrificed 7 days after the 2nd injection. Although the use of human bone marrow-derived (hBM) hBM-MSC or DFT alone enabled partial resolution of the thrombus, combining them resulted in near-complete resolution. Neovascularization was two-fold better in hBM-MSC + DFT treated rats (11.6 ± 2.4 channels) compared with the hBM-MSC (3.8 ± 2.7 channels) and DFT groups (5.5 ± 1.8 channels) (P < 0.0001 and P= 0.002, respectively). The combined use of hBM-MSC and DFT in a rat model of arterial thrombosis showed additive effect resulting in near-complete resolution of the thrombus.

[Effects of rapamycin on biological characteristics of bone marrow mesenchymal stem cells from patients with aplastic anemia].

PubMed

Wang, Xin; Ma, Feng-Xia; Lu, Shi-Hong; Chi, Ying; Chen, Fang; Li, Xue; Li, Juan-Juan; Du, Wen-Jing; Feng, Ying; Cui, Jun-Jie; Song, Bao-Quan; Han, Zhong-Chao

2014-06-01

This study was aimed to investigate the effects of rapamycin on biological function and autophagy of bone marrow mesenchymal stem cells (BM-MSC) from patients with aplastic anemia so as to provide experimental basis for the clinical treatment of aplastic anemia (AA) with rapamycin. BM-MSC were treated with different concentrations of rapamycin (0, 10, 50, 100 nmol/L) for 48 h, the expression of LC3B protein was detected by Western blot to observe the effect of rapamycin on cell autophagy; cell apoptosis and cell cycles were detected by flow cytometry; the proliferation of BM-MSC of AA patients was measured by cell counting kit-8; the adipogenic differentiation of BM-MSC were tested by oil red O staining after adipogenic induction for 2 weeks; the adipogenic related genes (LPL, CFD, PPARγ) were detected by real-time PCR. The results showed that the proliferation and adipogenesis of BM-MSC of AA patients were inhibited by rapamycin. Moreover, the autophagy and apoptosis of BM-MSC were increased by rapamycin in a dose-dependent way.Rapamycin arrested the BM-MSC in G0/G1 phase and prevented them into S phase (P < 0.05). It is concluded that rapamycin plays an critical role in inhibiting cell proliferation, cell cycles, and adipogenesis, these effects may be related with the autophagy activation and mTOR inhibition resulting from rapamycin.

Gilz-Activin A as a Novel Signaling Axis Orchestrating Mesenchymal Stem Cell and Th17 Cell Interplay

PubMed Central

Luz-Crawford, Patricia; Espinosa-Carrasco, Gabriel; Ipseiz, Natacha; Contreras, Rafael; Tejedor, Gautier; Medina, Daniel A.; Vega-Letter, Ana-Maria; Ngo, Devi; Morand, Eric F.; Pène, Jérôme; Hernandez, Javier; Jorgensen, Christian; Djouad, Farida

2018-01-01

Mesenchymal stem cells (MSC) are highly immunosuppressive cells able to reduce chronic inflammation through the active release of mediators. Recently, we showed that glucocorticoid-induced leucine zipper (Gilz) expression by MSC is involved in their therapeutic effect by promoting the generation of regulatory T cells. However, the mechanisms underlying this pivotal role of Gilz remain elusive. Methods and Results In this study, we have uncovered evidence that Gilz modulates the phenotype and function of Th1 and Th17 cells likely by upregulating the level of Activin A and NO2 secreted by MSC. Adoptive transfer experiments sustained this Gilz-dependent suppressive effect of MSC on Th1 and Th17 cell functions. In immunoregulatory MSC, obtained by priming with IFN-γ and TNF-α, Gilz was translocated to the nucleus and bound to the promoters of inos and Activin βA to induce their expression. The increased expression of Activin A directly impacted on Th17 cells fate by repressing their differentiation program through the activation of Smad3/2 and enhancing IL-10 production. Conclusion Our results reveal how Gilz controls inos and Activin βA gene expression to ultimately assign immunoregulatory status to MSC able to repress the pathogenic Th17 cell differentiation program and uncover Activin A as a novel mediator of MSC in this process. PMID:29344311

Gilz-Activin A as a Novel Signaling Axis Orchestrating Mesenchymal Stem Cell and Th17 Cell Interplay.

PubMed

Luz-Crawford, Patricia; Espinosa-Carrasco, Gabriel; Ipseiz, Natacha; Contreras, Rafael; Tejedor, Gautier; Medina, Daniel A; Vega-Letter, Ana-Maria; Ngo, Devi; Morand, Eric F; Pène, Jérôme; Hernandez, Javier; Jorgensen, Christian; Djouad, Farida

2018-01-01

Mesenchymal stem cells (MSC) are highly immunosuppressive cells able to reduce chronic inflammation through the active release of mediators. Recently, we showed that glucocorticoid-induced leucine zipper (Gilz) expression by MSC is involved in their therapeutic effect by promoting the generation of regulatory T cells. However, the mechanisms underlying this pivotal role of Gilz remain elusive. Methods and Results In this study, we have uncovered evidence that Gilz modulates the phenotype and function of Th1 and Th17 cells likely by upregulating the level of Activin A and NO 2 secreted by MSC. Adoptive transfer experiments sustained this Gilz-dependent suppressive effect of MSC on Th1 and Th17 cell functions. In immunoregulatory MSC, obtained by priming with IFN-γ and TNF-α, Gilz was translocated to the nucleus and bound to the promoters of inos and Activin βA to induce their expression. The increased expression of Activin A directly impacted on Th17 cells fate by repressing their differentiation program through the activation of Smad3/2 and enhancing IL-10 production. Conclusion Our results reveal how Gilz controls inos and Activin βA gene expression to ultimately assign immunoregulatory status to MSC able to repress the pathogenic Th17 cell differentiation program and uncover Activin A as a novel mediator of MSC in this process.

Mechanisms of kidney repair by human mesenchymal stromal cells after ischemia: a comprehensive view using label-free MS(E).

PubMed

da Costa, Milene R; Pizzatti, Luciana; Lindoso, Rafael S; Sant'Anna, Julliana Ferreira; DuRocher, Barbara; Abdelhay, Eliana; Vieyra, Adalberto

2014-06-01

Acute kidney injury (AKI) is one of the more frequent and lethal pathological conditions seen in intensive care units. Currently available treatments are not totally effective but stem cell-based therapies are emerging as promising alternatives, especially the use of mesenchymal stromal cells (MSC), although the signaling pathways involved in their beneficial actions are not fully understood. The objective of this study was to identify signaling networks and key proteins involved in the repair of ischemia by MSC. Using an in vitro model of AKI to investigate paracrine interactions and label-free high definition 2D-NanoESI-MS(E) , differentially expressed proteins were identified in a human renal proximal tubule cell lineage (HK-2) exposed to human MSC (hMSC) after an ischemic insult. In silico analysis showed that hMSC stimulated antiapoptotic activity, normal ROS handling, energy production, cytoskeleton organization, protein synthesis, and cell proliferation. The proteomic data were validated by parallel experiments demonstrating reduced apoptosis in HK-2 cells and recovery of intracellular ATP levels. qRT-PCR for proteins implicated in the above processes revealed that hMSC exerted their effects by stimulating translation, not transcription. Western blotting of proteins associated with ROS and energy metabolism confirmed their higher abundance in HK-2 cells exposed to hMSC. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

First Apollo 11 Lunar Samples Arrive at the Manned Spacecraft Center (MSC)

NASA Technical Reports Server (NTRS)

1969-01-01

The Apollo 11 mission, the first manned lunar mission, launched from the Kennedy Space Center, Florida via the Marshall Space Flight Center (MSFC) developed Saturn V launch vehicle on July 16, 1969 and safely returned to Earth on July 24, 1969. Aboard the space craft were astronauts Neil A. Armstrong, commander; Michael Collins, Command Module (CM) pilot; and Edwin E. Aldrin Jr., Lunar Module (LM) pilot. The CM, piloted by Michael Collins remained in a parking orbit around the Moon while the LM, named 'Eagle'', carrying astronauts Neil Armstrong and Edwin Aldrin, landed on the Moon. During 2½ hours of surface exploration, the crew collected 47 pounds of lunar surface material for analysis back on Earth. This photograph was taken as the mission's first loaded sample return container arrived at Ellington Air Force Base by air from the Pacific recovery area. The rock box was immediately taken to the Lunar Receiving Laboratory at the Manned Spacecraft Center (MSC) in Houston, Texas. Happily posing for the photograph with the rock container are (L-R) Richard S. Johnston (back), special assistant to the MSC Director; George M. Low, MSC Apollo Spacecraft Program manager; George S. Trimble (back), MSC Deputy Director; Lt. General Samuel C. Phillips, Apollo Program Director, Office of Manned Spaceflight at NASA headquarters; Eugene G. Edmonds, MSC Photographic Technology Laboratory; Dr. Thomas O. Paine, NASA Administrator; and Dr. Robert R. Gilruth, MSC Director.

Cell therapy in joint disorders.

PubMed

Counsel, Peter D; Bates, Daniel; Boyd, Richard; Connell, David A

2015-01-01

Articular cartilage possesses poor natural healing mechanisms, and a variety of non-cell-based and cell-based treatments aim to promote regeneration of hyaline cartilage. A review of the literature to December 2013 using PubMed with search criteria including the keywords stem cell, cell therapy, cell transplantation, cartilage, chondral, and chondrogenic. Forty-five articles were identified that employed local mesenchymal stem cell (MSC) therapy for joint disorders in humans. Nine comparative studies were identified, consisting of 3 randomized trials, 5 cohort studies, and 1 case-control study. Clinical review. Level 4. Studies were assessed for stem cell source, method of implantation, comparison groups, and concurrent surgical techniques. Two studies comparing MSC treatment to autologous chondrocyte implantation found similar efficacy. Three studies reported clinical benefits with intra-articular MSC injection over non-MSC controls for cases undergoing debridement with or without marrow stimulation, although a randomized study found no significant clinical difference at 2-year follow-up but reported better 18-month magnetic resonance imaging and histologic scores in the MSC group. No human studies have compared intra-articular MSC therapy to non-MSC techniques for osteoarthritis in the absence of surgery. Mesenchymal stem cell-based therapies appear safe and effective for joint disorders in large animal preclinical models. Evidence for use in humans, particularly, comparison with more established treatments such as autologous chondrocyte implantation and microfracture, is limited.

Combination therapy with intra-articular injection of mesenchymal stem cells and articulated joint distraction for repair of a chronic osteochondral defect in the rabbit.

PubMed

Harada, Yohei; Nakasa, Tomoyuki; Mahmoud, Elhussein Elbadry; Kamei, Goki; Adachi, Nobuo; Deie, Masataka; Ochi, Mitsuo

2015-10-01

The present study investigated intra-articular injection of bone-marrow-derived mesenchymal stem cells (MSCs) combined with articulated joint distraction as treatment for osteochondral defects. Large osteochondral defects were created in the weight-bearing area of the medial femoral condyle in rabbit knees. Four weeks after defect creation, rabbits were divided into six groups: control group, MSC group, distraction group, distraction + MSC group, temporary distraction group, and temporary distraction + MSC group. Groups with MSC received intra-articular injection of MSCs. Groups with distraction underwent articulated distraction arthroplasty. Groups with temporary distraction discontinued the distraction after 4 weeks. The rabbits were euthanized at 4, 8, and 12 weeks after treatment except temporary distraction groups which were euthanized at only 12 weeks. Histological scores in the distraction + MSC group were significantly better than in the control, MSC group or distraction group at 4 and 8 weeks, but showed no further improvement. At 12 weeks, the temporary distraction + MSC group showed the best results, demonstrating hyaline cartilage repair with regeneration of the osteochondral junction. In conclusion, joint distraction with intra-articular injection of MSCs promotes early cartilage repair, and compressive loading of the repair tissue after temporary distraction stimulates articular cartilage regeneration. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Assessing the containment efficiency of a microbiological safety cabinet during the simultaneous generation of a nanoaerosol and a tracer gas.

PubMed

Cesard, V; Belut, E; Prevost, C; Taniere, A; Rimbert, N

2013-04-01

The intention of this article is to compare the containment performance of a Type II microbiological safety cabinet (MSC) confronted with the simultaneous generation of a saline nanoparticle aerosol and a tracer gas (SF(6)). The back dissemination coefficient, defined as the ratio of the pollutant concentration measured outside the enclosure to the pollutant flow rate emitted inside the enclosure, is calculated in order to quantify the level of protection of each airborne contaminant tested for three enclosure operating configurations: an initial configuration (without perturbations), a configuration exposing a dummy in front of the enclosure (simulation of an operator), and a configuration employing the movement of a plate in front of the enclosure (simulation of human movement). Based on the results of this study, we observed that nanoparticulate and gaseous behaviours are strongly correlated, thus showing the predominance of air-driven transport over particle-specific behaviour. The average level of protection afforded by the MSC was found systematically slightly higher for the nanoaerosol than for the gas in the studied configurations (emission properties of the source, operating conditions, and measurement protocols). This improved protection efficiency, however, cannot be considered as a warrant of protection for operators since operating condition and ventilation parameters are still more influential on the containment than the pollutant nature (i.e. nanoaerosol or gas).

Application test of a Detection Method for the Enclosed Turbine Runner Chamber

NASA Astrophysics Data System (ADS)

Liu, Yunlong; Shen, Dingjie; Xie, Yi; Yang, Xiangwei; Long, Yi; Li, Wenbo

2017-06-01

At present, for the existing problems of the testing methods for the key hidden metal components of the turbine runner chamber, such as the poor reliability, the inaccurate locating and the larger detection blind spots of the detection device, under the downtime without opening the cover of the hydropower turbine runner chamber, an automatic detection method based on real-time image acquisition and simulation comparison techniques was proposed. By using the permanent magnet wheel, the magnetic crawler which carry the real-time image acquisition device, could complete the crawling work on the inner surface of the enclosed chamber. Then the image acquisition device completed the real-time collection of the scene image of the enclosed chamber. According to the obtained location by using the positioning auxiliary device, the position of the real-time detection image in a virtual 3D model was calibrated. Through comparing of the real-time detection images and the computer simulation images, the defects or foreign matter fall into could be accurately positioning, so as to repair and clean up conveniently.

Note: The design of thin gap chamber simulation signal source based on field programmable gate array.

PubMed

Hu, Kun; Lu, Houbing; Wang, Xu; Li, Feng; Liang, Futian; Jin, Ge

2015-01-01

The Thin Gap Chamber (TGC) is an important part of ATLAS detector and LHC accelerator. Targeting the feature of the output signal of TGC detector, we have designed a simulation signal source. The core of the design is based on field programmable gate array, randomly outputting 256-channel simulation signals. The signal is generated by true random number generator. The source of randomness originates from the timing jitter in ring oscillators. The experimental results show that the random number is uniform in histogram, and the whole system has high reliability.

Note: The design of thin gap chamber simulation signal source based on field programmable gate array

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hu, Kun; Wang, Xu; Li, Feng

The Thin Gap Chamber (TGC) is an important part of ATLAS detector and LHC accelerator. Targeting the feature of the output signal of TGC detector, we have designed a simulation signal source. The core of the design is based on field programmable gate array, randomly outputting 256-channel simulation signals. The signal is generated by true random number generator. The source of randomness originates from the timing jitter in ring oscillators. The experimental results show that the random number is uniform in histogram, and the whole system has high reliability.

Performance of a transpiration-regenerative cooled rocket thrust chamber

NASA Technical Reports Server (NTRS)

Valler, H. W.

1979-01-01

The analysis, design, fabrication, and testing of a liquid rocket engine thrust chamber which is gas transpiration cooled in the high heat flux convergent portion of the chamber and water jacket cooled (simulated regenerative) in the barrel and divergent sections of the chamber are described. The engine burns LOX-hydrogen propellants at a chamber pressure of 600 psia. Various transpiration coolant flow rates were tested with resultant local hot gas wall temperatures in the 800 F to 1400 F range. The feasibility of transpiration cooling with hydrogen and helium, and the use of photo-etched copper platelets for heat transfer and coolant metering was successfully demonstrated.

Multipotent mesenchymal stromal cell sheet therapy for bisphosphonate-related osteonecrosis of the jaw in a rat model.

PubMed

Kaibuchi, Nobuyuki; Iwata, Takanori; Yamato, Masayuki; Okano, Teruo; Ando, Tomohiro

2016-09-15

Bisphosphonates (BPs) inhibit bone resorption and are frequently used to treat osteoporosis, bone metastasis, and other conditions that result in bone fragility. However, numerous studies have reported that BPs are closely related to the development of osteonecrosis of the jaw (BRONJ), which is an intractable disease. Recent studies have demonstrated that intravenous infusion of multipotent mesenchymal stromal cells (MSCs) is effective for the treatment of BRONJ-like disease models. However, the stability of injected MSCs is relatively low. In this study, the protein level of vascular endothelial growth factor in BP-treated MSCs was significantly lower than untreated-MSCs. The mRNA expression levels of receptor activator of nuclear factor κ-B ligand and osteoprotegerin were significantly decreased in BP-treated MSCs. We developed a tissue-engineered cell sheet of allogeneic enhanced green fluorescent protein (EGFP)-labeled MSCs and investigated the effect of MSC sheet transplantation in a BRONJ-like rat model. The MSC sheet group showed wound healing in most cases compared with the control group and MSC intravenous injection group (occurrence of bone exposure: 12.5% compared with 80% and 100%, respectively). Immunofluorescence staining revealed that EGFP-positive cells were localized around newly formed blood vessels in the transplanted sub-mucosa at 2weeks after transplantation. Blood vessels were significantly observed in the MSC sheet group compared to in the control group and MSC intravenous injection group (106±9.6 compared with 40±5.3 and 62±10.2 vessels/mm(2), respectively). These results suggest that allogeneic MSC sheet transplantation is a promising alternative approach for treating BRONJ. Bisphosphonates are frequently used to treat osteoporosis, bone metastasis of various cancers, and other diseases. However, bisphosphonate related-osteonecrosis of the jaw (BRONJ) is an intractable disease because it often recurs after surgery or is exacerbated following conservative treatment. Therefore, an alternative approach for treating BRONJ is needed. In this study, we developed a bone marrow-derived multipotent mesenchymal stromal cell (MSC) sheet to treat BRONJ and investigated the effect of MSC sheet transplantation in a rat model of BRONJ-like disease. The MSC sheet transplantation group showed wound healing in most cases, while only minimal healing was observed in the control group and MSC intravenous injection group. Our results suggest that the MSC sheet is a promising alternative approach for the treatment of BRONJ. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Stoichiometry of the large conductance bacterial mechanosensitive channel of E. coli. A biochemical study

NASA Technical Reports Server (NTRS)

Sukharev, S. I.; Schroeder, M. J.; McCaslin, D. R.

1999-01-01

MscL, a 15 kDa transmembrane protein, is the only component involved in the formation of a 3 nS channel in the inner membrane of Escherichia coli that opens in response to mechanical or osmotic stress. While previous data had suggested that the functional MscL complex might be a hexamer, a recent crystallographic study of the MscL homologue from M. tuberculosis reveals a pentameric structure. The present work further examines the stoichiometry of the E. coli MscL using a variety of biochemical approaches. Detergent-purified 6His-MscL in solution and MscL in the membrane could be chemically crosslinked with the products displaying ladderlike patterns on SDS gels. Three crosslinking agents (EDC, DMS, and DMA) used at saturating concentrations invariably generated pentamers as the largest product. DSS produced additional bands corresponding to larger complexes although the pentamer band appeared to be the predominant product at high levels of crosslinker. It is not clear whether these extra bands reflect a difference in the crosslinking chemistry of DSS or whether its spacer arm is the longest of those used, or a combination of both facts. For the detergent-solubilized 6His-MscL both sedimentation equilibrium and gel chromatography showed the presence of multiple species. Thus the longer spacer arm could permit both intra- and intercomplex linkages. Nonetheless, the patterns obtained with all agents are consistent with and strongly suggest a pentameric organization for the MscL channel. Expression of MscL as genetically engineered double or triple subunit tandems yields low numbers of functional channels as compared to expressed monomers. The double-tandem assemblies must have an even number of subunits and crosslinking in the membrane confirmed hexamerization. Gel chromatography clearly demonstrated that the channels formed from the double tandems were larger than those formed from WT MscL, consistent with the native channel being pentameric. The observation that both double and triple tandems form channels of normal conductance implies that the pentameric assembly is to some degree independent of the number of subunit repeats in the polypeptide precursor. The channel is thus a pentameric core with the 'extra' subunits left out of the functional complex. From sedimentation equilibrium and size-exclusion chromatography, we also conclude that MscL complexes are not in a dynamic equilibrium with monomers, but are pre-assembled; and thus, their gating properties must result from changes in the conformation of the entire complex induced by the mechanical stress.

Stoichiometry of the large conductance bacterial mechanosensitive channel of E. coli. A biochemical study.

PubMed

Sukharev, S I; Schroeder, M J; McCaslin, D R

1999-10-01

MscL, a 15 kDa transmembrane protein, is the only component involved in the formation of a 3 nS channel in the inner membrane of Escherichia coli that opens in response to mechanical or osmotic stress. While previous data had suggested that the functional MscL complex might be a hexamer, a recent crystallographic study of the MscL homologue from M. tuberculosis reveals a pentameric structure. The present work further examines the stoichiometry of the E. coli MscL using a variety of biochemical approaches. Detergent-purified 6His-MscL in solution and MscL in the membrane could be chemically crosslinked with the products displaying ladderlike patterns on SDS gels. Three crosslinking agents (EDC, DMS, and DMA) used at saturating concentrations invariably generated pentamers as the largest product. DSS produced additional bands corresponding to larger complexes although the pentamer band appeared to be the predominant product at high levels of crosslinker. It is not clear whether these extra bands reflect a difference in the crosslinking chemistry of DSS or whether its spacer arm is the longest of those used, or a combination of both facts. For the detergent-solubilized 6His-MscL both sedimentation equilibrium and gel chromatography showed the presence of multiple species. Thus the longer spacer arm could permit both intra- and intercomplex linkages. Nonetheless, the patterns obtained with all agents are consistent with and strongly suggest a pentameric organization for the MscL channel. Expression of MscL as genetically engineered double or triple subunit tandems yields low numbers of functional channels as compared to expressed monomers. The double-tandem assemblies must have an even number of subunits and crosslinking in the membrane confirmed hexamerization. Gel chromatography clearly demonstrated that the channels formed from the double tandems were larger than those formed from WT MscL, consistent with the native channel being pentameric. The observation that both double and triple tandems form channels of normal conductance implies that the pentameric assembly is to some degree independent of the number of subunit repeats in the polypeptide precursor. The channel is thus a pentameric core with the 'extra' subunits left out of the functional complex. From sedimentation equilibrium and size-exclusion chromatography, we also conclude that MscL complexes are not in a dynamic equilibrium with monomers, but are pre-assembled; and thus, their gating properties must result from changes in the conformation of the entire complex induced by the mechanical stress.

Metabolic syndrome alters expression of insulin signaling-related genes in swine mesenchymal stem cells.

PubMed

Conley, Sabena M; Zhu, Xiang-Yang; Eirin, Alfonso; Tang, Hui; Lerman, Amir; van Wijnen, Andre J; Lerman, Lilach O

2018-02-20

Metabolic syndrome (MetS) is associated with insulin resistance (IR) and impaired glucose metabolism in muscle, fat, and other cells, and may induce inflammation and vascular remodeling. Endogenous reparative systems, including adipose tissue-derived mesenchymal stem/stromal cells (MSC), are responsible for repair of damaged tissue. MSC have also been proposed as an exogenous therapeutic intervention in patients with cardiovascular and chronic kidney disease (CKD). The feasibility of using autologous cells depends on their integrity, but whether in MetS IR involves adipose tissue-derived MSC remains unknown. The aim of this study was to examine the expression of mRNA involved in insulin signaling in MSC from subjects with MetS. Domestic pigs consumed a lean or obese diet (n=6 each) for 16weeks. MSC were collected from subcutaneous abdominal fat and analyzed using high-throughput RNA-sequencing for expression of genes involved in insulin signaling. Expression profiles for enriched (fold change>1.4, p<0.05) and suppressed (fold change<0.7, p<0.05) mRNAs in MetS pigs were functionally interpreted by gene ontology analysis. The most prominently upregulated and downregulated mRNAs were further probed. We identified in MetS-MSC 168 up-regulated and 51 down-regulated mRNAs related to insulin signaling. Enriched mRNAs were implicated in biological pathways including hepatic glucose metabolism, adipocyte differentiation, and transcription regulation, and down-regulated mRNAs in intracellular calcium signaling and cleaving peptides. Functional analysis suggested that overall these alterations could increase IR. MetS alters mRNA expression related to insulin signaling in adipose tissue-derived MSC. These observations mandate caution during administration of autologous MSC in subjects with MetS. Copyright © 2017. Published by Elsevier B.V.

Mesenchymal Stem Cells Promote the Osteogenesis in Collagen-Induced Arthritic Mice through the Inhibition of TNF-α

PubMed Central

Liu, Chang; Tang, Xiaojun; Feng, Ruihai; Yao, Genhong; Chen, Weiwei; Li, Wenchao; Liang, Jun; Feng, Xuebing

2018-01-01

Objective To investigate the effects of umbilical cord mesenchymal stem cell (UC-MSC) transplantation on joint damage and osteoporosis in collagen-induced arthritis (CIA) mice and to explore the mechanisms by which UC-MSCs modulate the osteogenic differentiation. Methods CIA mice were divided into the following treated groups: UC-MSC transplantation group, antitumor necrosis factor- (TNF-) α group, and zoledronic acid (ZA) group. Microcomputed tomography (micro-CT) was used to analyze the bone morphology parameters. Osteogenic differentiation of treated CIA mice was determined. Bone marrow mesenchymal stem cells (BM-MSCs) from CIA mice were treated with TNF-α in vitro to explore their effects on osteogenesis. Results The arthritis score was significantly reduced in the UC-MSC transplantation and anti-TNF-α-treated CIA groups, compared with control mice (P < 0.001). Micro-CT showed that CIA mice developed osteoporosis at 12 weeks after immunization. The bone morphology parameters were partially improved in UC-MSC-treated CIA mice. Impaired osteogenic differentiation functions were indicated by decreased ALP activity (P < 0.001) and reduced mRNA and protein levels of osteogenic marker genes (P < 0.05) in CIA mice compared with DBA/1 mice. UC-MSC treatment significantly upregulated the impaired osteogenic differentiation ability in CIA mice. Meanwhile, the serum TNF-α level was decreased significantly in the UC-MSC group. The osteogenesis was reduced with the addition of TNF-α in vitro. Conclusion This study demonstrated that UC-MSC transplantation not only significantly improved the joint damage but also played a beneficial role in osteoporosis in CIA mice. Mechanistically, the improved osteogenic differentiation of CIA under UC-MSC treatment may be achieved by inhibition of TNF-α. PMID:29853911

Transplantation of Mesenchymal Stem Cells Promotes an Alternative Pathway of Macrophage Activation and Functional Recovery after Spinal Cord Injury

PubMed Central

Uchida, Kenzo; Guerrero, Alexander Rodriguez; Watanabe, Shuji; Sugita, Daisuke; Takeura, Naoto; Yoshida, Ai; Long, Guang; Wright, Karina T.; Johnson, William E.B.; Baba, Hisatoshi

2012-01-01

Abstract Mesenchymal stem cells (MSC) derived from bone marrow can potentially reduce the acute inflammatory response in spinal cord injury (SCI) and thus promote functional recovery. However, the precise mechanisms through which transplanted MSC attenuate inflammation after SCI are still unclear. The present study was designed to investigate the effects of MSC transplantation with a special focus on their effect on macrophage activation after SCI. Rats were subjected to T9–T10 SCI by contusion, then treated 3 days later with transplantation of 1.0×106 PKH26-labeled MSC into the contusion epicenter. The transplanted MSC migrated within the injured spinal cord without differentiating into glial or neuronal elements. MSC transplantation was associated with marked changes in the SCI environment, with significant increases in IL-4 and IL-13 levels, and reductions in TNF-α and IL-6 levels. This was associated simultaneously with increased numbers of alternatively activated macrophages (M2 phenotype: arginase-1- or CD206-positive), and decreased numbers of classically activated macrophages (M1 phenotype: iNOS- or CD16/32-positive). These changes were associated with functional locomotion recovery in the MSC-transplanted group, which correlated with preserved axons, less scar tissue formation, and increased myelin sparing. Our results suggested that acute transplantation of MSC after SCI modified the inflammatory environment by shifting the macrophage phenotype from M1 to M2, and that this may reduce the effects of the inhibitory scar tissue in the subacute/chronic phase after injury to provide a permissive environment for axonal extension and functional recovery. PMID:22233298

β3-Adrenergic Regulation of EPC Features Through Manipulation of the Bone Marrow MSC Niche.

PubMed

Vafaei, Rana; Nassiri, Seyed Mahdi; Siavashi, Vahid

2017-12-01

Mesenchymal stem cells (MSCs) reside in a specific niche in the bone marrow, however, biological features of this niche are still not fully understood. Given the interactions of MSCs with endothelial cells in different tissues, bone marrow MSC niche may influence the biological features of endothelial progenitor cells (EPCs). To understand the role of the sympathetic nervous system in regulation of the MSC niche, we examined whether the manipulation of the MSC niche via β3-adrenergic signals will affect EPC features. A selective β3 agonist (BRL37344) or a β3 antagonist (SR59230A) was administered in mice for 2 weeks to determine the potential effects of these regimens on the population of CD133 + stem cells in the bone marrow. Then, bone marrow-derived MSCs and EPCs were harvested and expanded from the mice to examine the effect of changes in the MSC niche on EPC features. Improved MSC colony forming potency with increased bone marrow stromal cell-derived factor 1 (SDF-1) (also known as C-X-C motif chemokine 12 [CXCL12]) expression was shown as a result of intensification of the bone marrow adrenergic signals through BRL37344 injection. On the other hand, the blockage of these signals limited the expression level of SDF-1 and resulted in bone marrow enrichment of CD133 + cells. Manipulation of the MSC niche and decreased SDF-1 expression via SR59230A injection also prompted EPCs to form more colonies with augmented proliferation and differentiation capacity. Overall, our results indicate that the β3-adrenergic signals regulate the MSC niche, thereby resulting in modulation of EPC biological features. J. Cell. Biochem. 118: 4753-4761, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

High targeted migration of human mesenchymal stem cells grown in hypoxia is associated with enhanced activation of RhoA

PubMed Central

2013-01-01

Introduction A feature which makes stem cells promising candidates for cell therapy is their ability to migrate effectively into damaged or diseased tissues. Recent reports demonstrated the increased motility of human mesenchymal stem cells (hMSC) grown under hypoxic conditions compared to normoxic cells. However, the directional migration of hMSC cultured in hypoxia has not been investigated. In this study we examined the in vitro transmembrane migration of hMSC permanently cultured in hypoxia in response to various cytokines. We also studied the involvement of RhoA, a molecule believed to play an essential role in the migration of MSC via reorganization of the cytoskeleton. Methods We compared the directional migration of human hMSCs grown permanently under normal (21%, normoxic) and low O2 (5%, hypoxic) conditions until passage 4 using an in vitro transmembrane migration assay. A series of 17 cytokines was used to induce chemotaxis. We also compared the level of GTP-bound RhoA in the cell extracts of calpeptin-activated hypoxic and normoxic hMSC. Results We found that hMSC cultured in hypoxia demonstrate markedly higher targeted migration activity compared to normoxic cells, particularly towards wound healing cytokines, including those found in ischemic and myocardial infarction. We also demonstrated for the first time that hMSC are dramatically more sensitive to activation of RhoA. Conclusions The results of this study indicate that high directional migration of hMSCs permanently grown in hypoxia is associated with the enhanced activation of RhoA. The enhanced migratory capacity of hypoxic hMSC would further suggest their potential advantages for clinical applications. PMID:23295150

Dynamic Fluid Flow Mechanical Stimulation Modulates Bone Marrow Mesenchymal Stem Cells.

PubMed

Hu, Minyi; Yeh, Robbin; Lien, Michelle; Teeratananon, Morgan; Agarwal, Kunal; Qin, Yi-Xian

2013-03-01

Osteoblasts are derived from mesenchymal stem cells (MSCs), which initiate and regulate bone formation. New strategies for osteoporosis treatments have aimed to control the fate of MSCs. While functional disuse decreases MSC growth and osteogenic potentials, mechanical signals enhance MSC quantity and bias their differentiation toward osteoblastogenesis. Through a non-invasive dynamic hydraulic stimulation (DHS), we have found that DHS can mitigate trabecular bone loss in a functional disuse model via rat hindlimb suspension (HLS). To further elucidate the downstream cellular effect of DHS and its potential mechanism underlying the bone quality enhancement, a longitudinal in vivo study was designed to evaluate the MSC populations in response to DHS over 3, 7, 14, and 21 days. Five-month old female Sprague Dawley rats were divided into three groups for each time point: age-matched control, HLS, and HLS+DHS. DHS was delivered to the right mid-tibiae with a daily "10 min on-5 min off-10 min on" loading regime for five days/week. At each sacrifice time point, bone marrow MSCs of the stimulated and control tibiae were isolated through specific cell surface markers and quantified by flow cytometry analysis. A strong time-dependent manner of bone marrow MSC induction was observed in response to DHS, which peaked on day 14. After 21 days, this effect of DHS was diminished. This study indicates that the MSC pool is positively influenced by the mechanical signals driven by DHS. Coinciding with our previous findings of mitigation of disuse bone loss, DHS induced changes in MSC number may bias the differentiation of the MSC population towards osteoblastogenesis, thereby promoting bone formation under disuse conditions. This study provides insights into the mechanism of time-sensitive MSC induction in response to mechanical loading, and for the optimal design of osteoporosis treatments.

Cardiac mesenchymal stromal cells are a source of adipocytes in arrhythmogenic cardiomyopathy.

PubMed

Sommariva, E; Brambilla, S; Carbucicchio, C; Gambini, E; Meraviglia, V; Dello Russo, A; Farina, F M; Casella, M; Catto, V; Pontone, G; Chiesa, M; Stadiotti, I; Cogliati, E; Paolin, A; Ouali Alami, N; Preziuso, C; d'Amati, G; Colombo, G I; Rossini, A; Capogrossi, M C; Tondo, C; Pompilio, G

2016-06-14

Arrhythmogenic cardiomyopathy (ACM) is a genetic disorder mainly due to mutations in desmosomal genes, characterized by progressive fibro-adipose replacement of the myocardium, arrhythmias, and sudden death. It is still unclear which cell type is responsible for fibro-adipose substitution and which molecular mechanisms lead to this structural change. Cardiac mesenchymal stromal cells (C-MSC) are the most abundant cells in the heart, with propensity to differentiate into several cell types, including adipocytes, and their role in ACM is unknown. The aim of the present study was to investigate whether C-MSC contributed to excess adipocytes in patients with ACM. We found that, in ACM patients' explanted heart sections, cells actively differentiating into adipocytes are of mesenchymal origin. Therefore, we isolated C-MSC from endomyocardial biopsies of ACM and from not affected by arrhythmogenic cardiomyopathy (NON-ACM) (control) patients. We found that both ACM and control C-MSC express desmosomal genes, with ACM C-MSC showing lower expression of plakophilin (PKP2) protein vs. Arrhythmogenic cardiomyopathy C-MSC cultured in adipogenic medium accumulated more lipid droplets than controls. Accordingly, the expression of adipogenic genes was higher in ACM vs. NON-ACM C-MSC, while expression of cell cycle and anti-adipogenic genes was lower. Both lipid accumulation and transcription reprogramming were dependent on PKP2 deficiency. Cardiac mesenchymal stromal cells contribute to the adipogenic substitution observed in ACM patients' hearts. Moreover, C-MSC from ACM patients recapitulate the features of ACM adipogenesis, representing a novel, scalable, patient-specific in vitro tool for future mechanistic studies. © The Author 2015. Published by Oxford University Press on behalf of the European Society of Cardiology.

Featured Article: Dexamethasone and rosiglitazone are sufficient and necessary for producing functional adipocytes from mesenchymal stem cells

PubMed Central

Ezquer, Fernando; Espinosa, Maximiliano; Arango-Rodriguez, Martha; Puebla, Carlos; Sobrevia, Luis; Conget, Paulette

2015-01-01

The final product of adipogenesis is a functional adipocyte. This mature cell acquires the necessary machinery for lipid metabolism, loses its proliferation potential, increases its insulin sensitivity, and secretes adipokines. Multipotent mesechymal stromal cells have been recognized as a source of adipocytes both in vivo and in vitro. The in vitro adipogenic differentiation of human MSC (hMSC) has been induced up to now by using a complex stimulus which includes dexamethasone, 3-isobutyl-1-methylxanthine, indomethacin, and insulin (a classical cocktail) and evaluated according to morphological changes. The present work was aimed at demonstrating that the simultaneous activation of dexamethasone’s canonical signaling pathways, through the glucocorticoid receptor and CCAAT-enhancer-binding proteins (C/EBPs) and rosiglitazone through peroxisome proliferator-activated receptor gamma (PPAR-gamma) is sufficient yet necessary for inducing hMSC adipogenic differentiation. It was also ascertained that hMSC exposed just to dexamethasone and rosiglitazone (D&R) differentiated into cells which accumulated neutral lipid droplets, expressed C/EBP-alpha, PPAR-gamma, aP2, lipoprotein lipase, acyl-CoA synthetase, phosphoenolpyruvate carboxykinase, adiponectin, and leptin genes but did not proliferate. Glucose uptake was dose dependent on insulin stimulus and high levels of adipokines were secreted (i.e. displaying not only the morphology but also expressing mature adipocytes’ specific genes and functional characteristics). This work has demonstrated that (i) the activating C/EBPs and PPAR-gamma signaling pathways were sufficient to induce adipogenic differentiation from hMSC, (ii) D&R producing functional adipocytes from hMSC, (iii) D&R induce adipogenic differentiation from mammalian MSC (including those which are refractory to classical adipogenic differentiation stimuli). D&R would thus seem to be a useful tool for MSC characterization, studying adipogenesis pathways and producing functional adipocytes. PMID:25595190

Evaluation of GMP-compliant culture media for in vitro expansion of human bone marrow mesenchymal stromal cells.

PubMed

Wuchter, Patrick; Vetter, Marcel; Saffrich, Rainer; Diehlmann, Anke; Bieback, Karen; Ho, Anthony D; Horn, Patrick

2016-06-01

Mesenchymal stromal cells (MSCs) from human bone marrow serve as a resource for cell-based therapies in regenerative medicine. Clinical applications require standardized protocols according to good manufacturing practice (GMP) guidelines. Donor variability as well as the intrinsic heterogeneity of MSC populations must be taken into consideration. The composition of the culture medium is a key factor in successful MSC expansion. The aim of this study was to comparatively assess the efficiency of xeno-free human platelet lysate (HPL)-based cell expansion with two commercially available media-StemPro MSC SFM CTS (for human ex vivo tissue and cell culture processing applications) and MSCGM (non-GMP-compliant, for research only)-in an academic setting as the first optimization step toward GMP-compliant manufacturing. We report the feasibility of MSC expansion up to the yielded cell number with all three media. MSCs exhibited the typical fibroblastoid morphology, with distinct differences in cell size depending on the medium. The differentiation capacity and characteristic immunophenotype were confirmed for all MSC populations. Proliferation was highest using StemPro MSC SFM CTS, whereas HPL medium was more cost-effective and its composition could be adjusted individually according to the respective needs. In summary, we present a comprehensive evaluation of GMP-compatible culture media for MSC expansion. Both StemPro and HPL medium proved to be suitable for clinical application and allowed sufficient cell proliferation. Specific differences were observed and should be considered according to the intended use. This study provides a detailed cost analysis and tools that may be helpful for the establishment of GMP-compliant MSC expansion. Copyright © 2016 ISEH - International Society for Experimental Hematology. Published by Elsevier Inc. All rights reserved.

Betacellulin overexpression in mesenchymal stem cells induces insulin secretion in vitro and ameliorates streptozotocin-induced hyperglycemia in rats.

PubMed

Paz, Ana H; Salton, Gabrielle Dias; Ayala-Lugo, Ana; Gomes, Cristiano; Terraciano, Paula; Scalco, Rosana; Laurino, Claudia Cilene Fernandes Correia; Passos, Eduardo Pandolfi; Schneider, Marlon R; Meurer, Luise; Cirne-Lima, Elizabeth

2011-02-01

Betacellulin (BTC), a ligand of the epidermal growth factor receptor, has been shown to promote growth and differentiation of pancreatic β-cells and to improve glucose metabolism in experimental diabetic rodent models. Mesenchymal stem cells (MSCs) have been already proved to be multipotent. Recent work has attributed to rat and human MSCs the potential to differentiate into insulin-secreting cells. Our goal was to transfect rat MSCs with a plasmid containing BTC cDNA to guide MSC differentiation into insulin-producing cells. Prior to induction of cell MSC transfection, MSCs were characterized by flow cytometry and the ability to in vitro differentiate into mesoderm cell types was evaluated. After rat MSC characterization, these cells were electroporated with a plasmid containing BTC cDNA. Transfected cells were cultivated in Dulbecco's modified Eagle medium high glucose (H-DMEM) with 10 mM nicotinamide. Then, the capability of MSC-BTC to produce insulin in vitro and in vivo was evaluated. It was possible to demonstrate by radioimmunoassay analysis that 10(4) MSC-BTC cells produced up to 0.4 ng/mL of insulin, whereas MSCs transfected with the empty vector (negative control) produced no detectable insulin levels. Moreover, MSC-BTC were positive for insulin in immunohistochemistry assay. In parallel, the expression of pancreatic marker genes was demonstrated by molecular analysis of MSC-BTC. Further, when MSC-BTC were transplanted to streptozotocin diabetic rats, BTC-transfected cells ameliorated hyperglycemia from over 500 to about 200 mg/dL at 35 days post-cell transplantation. In this way, our results clearly demonstrate that BTC overabundance enhances glucose-induced insulin secretion in MSCs in vitro as well as in vivo.

Zoledronic acid prevents the tumor-promoting effects of mesenchymal stem cells via MCP-1 dependent recruitment of macrophages.

PubMed

Jia, Xiao-Hua; Du, Yang; Mao, Duo; Wang, Zhong-Liang; He, Zhen-Qiang; Qiu, Jing-Dan; Ma, Xi-Bo; Shang, Wen-Ting; Ding, Dan; Tian, Jie

2015-09-22

Zoledronic acid (ZA) has been tested in clinical trials as an additive therapy for early-stage breast cancer. However, the mechanism by which ZA exerts its antitumor activity is still unclear. The aim of this study is to investigate whether the prevention of tumor growth by ZA is through regulating the mesenchymal stem cells (MSC)-monocyte chemotactic protein 1 (MCP-1)-macrophages axis in the tumor microenvironment. To address this issue, MDA-MB-231-FLUC human breast cancer cells were cultured and injected either alone, or coupled with MSC into the mammary fat pads of nude mice. MSC were treated with either ZA or untreated. Tumor growth was determined by using an in vivo bioluminescence imaging (BLI) and the tumor-associated macrophages (TAMs) in tumor tissues were immunohistochemically analyzed by using CD206 antibody. The effects of ZA on the cytokine related gene expression of MSC were assessed by using real-time PCR. In this study, we found that ZA-treated mice showed a significant delay in tumor growth. In addition, our data revealed that ZA weakened the ability of MSC to promote tumor growth by impairing TAMs recruitment and tumor vascularization. Furthermore, it was found that ZA decreased MCP-1 expression of MSC, and therefore reduced the recruitment of TAMs to the tumor sites and hence inhibited the tumor growth. Altogether, our study demonstrated ZA can prevent the tumor-promoting effects of MSC. The antitumor effects of ZA were caused by decreasing the MCP-1 expression of MSC, which further decreased the infiltration of TAMs into tumor sites, and therefore inhibited the tumor growth.

Toll-like receptor 2 mediates mesenchymal stem cell-associated myocardial recovery and VEGF production following acute ischemia-reperfusion injury

PubMed Central

Abarbanell, Aaron M.; Wang, Yue; Herrmann, Jeremy L.; Weil, Brent R.; Poynter, Jeffrey A.; Manukyan, Mariuxi C.

2010-01-01

Toll-like receptor 2 (TLR2), a key component of the innate immune system, is linked to inflammation and myocardial dysfunction after ischemia-reperfusion injury (I/R). Treatment of the heart with mesenchymal stem cells (MSCs) is known to improve myocardial recovery after I/R in part by paracrine factors such as VEGF. However, it is unknown whether TLR2 activation on the MSCs affects MSC-mediated myocardial recovery and VEGF production. We hypothesized that the knockout of TLR2 on the MSCs (TLR2KO MSCs) would 1) improve MSC-mediated myocardial recovery and 2) increase myocardial and MSC VEGF release. With the isolated heart perfusion system, Sprague-Dawley rat hearts were subjected to I/R and received one of three intracoronary treatments: vehicle, male wild-type MSCs (MWT MSCs), or TL2KO MSCs. All treatments were performed immediately before ischemia, and heart function was measured continuously. Postreperfusion, heart homogenates were analyzed for myocardial VEGF production. Contrary to our hypothesis, only MWT MSC treatment significantly improved the recovery of left ventricular developed pressure and the maximal positive and negative values of the first derivative of pressure. In addition, VEGF production was greatest in hearts treated with MWT MSCs. To investigate MSC production of VEGF, MSCs were activated with TNF in vitro and the supernatants collected for ELISA. In vitro basal levels of MSC VEGF production were similar. However, with TNF activation, MWT MSCs produced significantly more VEGF, whereas activated TLR2KO MSC production of VEGF was unchanged. Finally, we observed that MWT MSCs proliferated more rapidly than TLR2KO MSCs. These data indicate that TLR2 may be essential to MSC-mediated myocardial recovery and VEGF production. PMID:20173040

Autologous c-Kit+ Mesenchymal Stem Cell Injections Provide Superior Therapeutic Benefit as Compared to c-Kit+ Cardiac-Derived Stem Cells in a Feline Model of Isoproterenol-Induced Cardiomyopathy.

PubMed

Taghavi, Sharven; Sharp, Thomas E; Duran, Jason M; Makarewich, Catherine A; Berretta, Remus M; Starosta, Tim; Kubo, Hajime; Barbe, Mary; Houser, Steven R

2015-10-01

Cardiac- (CSC) and mesenchymal-derived (MSC) CD117+ isolated stem cells improve cardiac function after injury. However, no study has compared the therapeutic benefit of these cells when used autologously. MSCs and CSCs were isolated on day 0. Cardiomyopathy was induced (day 28) by infusion of L-isoproterenol (1,100 ug/kg/hour) from Alzet minipumps for 10 days. Bromodeoxyuridine (BrdU) was infused via minipumps (50 mg/mL) to identify proliferative cells during the injury phase. Following injury (day 38), autologous CSC (n = 7) and MSC (n = 4) were delivered by intracoronary injection. These animals were compared to those receiving sham injections by echocardiography, invasive hemodynamics, and immunohistochemistry. Fractional shortening improved with CSC (26.9 ± 1.1% vs. 16.1 ± 0.2%, p = 0.01) and MSC (25.1 ± 0.2% vs. 12.1 ± 0.5%, p = 0.01) as compared to shams. MSC were superior to CSC in improving left ventricle end-diastolic (LVED) volume (37.7 ± 3.1% vs. 19.9 ± 9.4%, p = 0.03) and ejection fraction (27.7 ± 0.1% vs. 19.9 ± 0.4%, p = 0.02). LVED pressure was less in MSC (6.3 ± 1.3 mmHg) as compared to CSC (9.3 ± 0.7 mmHg) and sham (13.3 ± 0.7); p = 0.01. LV BrdU+ myocytes were higher in MSC (0.17 ± 0.03%) than CSC (0.09 ± 0.01%) and sham (0.06 ± 01%); p < 0.001. Both CD117+ isolated CSC and MSC therapy improve cardiac function and attenuate pathological remodeling. However, MSC appear to confer additional benefit. © 2015 Wiley Periodicals, Inc.

Soliciting Strategies for Developing Cell-Based Reference Materials to Advance Mesenchymal Stromal Cell Research and Clinical Translation

PubMed Central

Viswanathan, Sowmya; Keating, Armand; Deans, Robert; Hematti, Peiman; Prockop, Darwin; Stroncek, David F.; Stacey, Glyn; Weiss, Dan J.; Mason, Christopher

2014-01-01

The mesenchymal stromal cell (MSC) field continues to rapidly progress with a number of clinical trials initiated and completed, with some reported successes in multiple clinical indications, and a growing number of companies established. The field, nevertheless, faces several challenges. Persistent issues include the definition of a MSC and comparability between MSC preparations. This is because of inherent cell heterogeneity, the absence of markers that are unique to MSCs, and the difficulty in precisely defining them by developmental origin. Differences in the properties of MSCs also depend on the site of tissue harvest, phenotypic and genotypic characteristics of the donor and the isolation, and storage and expansion methods used. These differences may be sufficient to ensure that attributes of the final MSC product could differ in potentially significant ways. Since there are currently no gold standards, we propose using a reference material to establish methods of comparability among MSC preparations. We suggest four possible “ruler scenarios” and a method for global distribution. We further suggest that critical to establishing a reference material is the need to define protocols for comparing cells. The main purpose of this article is to solicit input in establishing a consensus-based comparison. A comparative approach will be critical to all stages of translation to better clarify mechanisms of MSC actions, define an optimal cell manufacturing process, ensure best practice clinical investigations, extend the use of an MSC product for new indications, protect an MSC product from imitators, and develop uniform reimbursement policies. Importantly, a reference material may enable a consensus on a practical definition of MSCs. PMID:24422625

Expansion in microcarrier-spinner cultures improves the chondrogenic potential of human early mesenchymal stromal cells.

PubMed

Lin, Youshan Melissa; Lim, Jessica Fang Yan; Lee, Jialing; Choolani, Mahesh; Chan, Jerry Kok Yen; Reuveny, Shaul; Oh, Steve Kah Weng

2016-06-01

Cartilage tissue engineering with human mesenchymal stromal cells (hMSC) is promising for allogeneic cell therapy. To achieve large-scale hMSC propagation, scalable microcarrier-based cultures are preferred over conventional static cultures on tissue culture plastic. Yet it remains unclear how microcarrier cultures affect hMSC chondrogenic potential, and how this potential is distinguished from that of tissue culture plastic. Hence, our study aims to compare the chondrogenic potential of human early MSC (heMSC) between microcarrier-spinner and tissue culture plastic cultures. heMSC expanded on either collagen-coated Cytodex 3 microcarriers in spinner cultures or tissue culture plastic were harvested for chondrogenic pellet differentiation with empirically determined chondrogenic inducer bone morphogenetic protein 2 (BMP2). Pellet diameter, DNA content, glycosaminoglycan (GAG) and collagen II production, histological staining and gene expression of chondrogenic markers including SOX9, S100β, MMP13 and ALPL, were investigated and compared in both conditions. BMP2 was the most effective chondrogenic inducer for heMSC. Chondrogenic pellets generated from microcarrier cultures developed larger pellet diameters, and produced more DNA, GAG and collagen II per pellet with greater GAG/DNA and collagen II/DNA ratios compared with that of tissue culture plastic. Moreover, they induced higher expression of chondrogenic genes (e.g., S100β) but not of hypertrophic genes (e.g., MMP13 and ALPL). A similar trend showing enhanced chondrogenic potential was achieved with another microcarrier type, suggesting that the mechanism is due to the agitated nature of microcarrier cultures. This is the first study demonstrating that scalable microcarrier-spinner cultures enhance the chondrogenic potential of heMSC, supporting their use for large-scale cell expansion in cartilage cell therapy. Copyright © 2016 International Society for Cellular Therapy. Published by Elsevier Inc. All rights reserved.

Enhancement of NAD+-dependent SIRT1 deacetylase activity by methylselenocysteine resets the circadian clock in carcinogen-treated mammary epithelial cells

PubMed Central

Fang, Mingzhu; Guo, Wei-Ren; Park, Youngil; Kang, Hwan-Goo; Zarbl, Helmut

2015-01-01

We previously reported that dietary methylselenocysteine (MSC) inhibits N-methyl-N-nitrosourea (NMU)-induced mammary tumorigenesis by resetting circadian gene expression disrupted by the carcinogen at the early stage of tumorigenesis. To investigate the underlying mechanism, we developed a circadian reporter system comprised of human mammary epithelial cells with a luciferase reporter driven by the promoter of human PERIOD 2 (PER2), a core circadian gene. In this in vitro model, NMU disrupted cellular circadian rhythm in a pattern similar to that observed with SIRT1-specific inhibitors; in contrast, MSC restored the circadian rhythms disrupted by NMU and protected against SIRT1 inhibitors. Moreover, NMU inhibited intracellular NAD+/NADH ratio and reduced NAD+-dependent SIRT1 activity in a dose-dependent manner, while MSC restored NAD+/NADH and SIRT1 activity in the NMU-treated cells, indicating that the NAD+-SIRT1 pathway was targeted by NMU and MSC. In rat mammary tissue, a carcinogenic dose of NMU also disrupted NAD+/NADH oscillations and decreased SIRT1 activity; dietary MSC restored NAD+/NADH oscillations and increased SIRT1 activity in the mammary glands of NMU-treated rats. MSC-induced SIRT1 activity was correlated with decreased acetylation of BMAL1 and increased acetylation of histone 3 lysine 9 at the Per2 promoter E-Box in mammary tissue. Changes in SIRT1 activity were temporally correlated with loss or restoration of rhythmic Per2 mRNA expression in NMU-treated or MSC-rescued rat mammary glands, respectively. Together with our previous findings, these results suggest that enhancement of NAD+-dependent SIRT1 activity contributes to the chemopreventive efficacy of MSC by restoring epigenetic regulation of circadian gene expression at early stages of mammary tumorigenesis. PMID:26544624

A novel 3D mesenchymal stem cell model of the multiple myeloma bone marrow niche: biologic and clinical applications

PubMed Central

Jakubikova, Jana; Cholujova, Danka; Hideshima, Teru; Gronesova, Paulina; Soltysova, Andrea; Harada, Takeshi; Joo, Jungnam; Kong, Sun-Young; Szalat, Raphael E.; Richardson, Paul G.; Munshi, Nikhil C.; Dorfman, David M.; Anderson, Kenneth C.

2016-01-01

Specific niches within the tumor bone marrow (BM) microenvironment afford a sanctuary for multiple myeloma (MM) clones due to stromal cell-tumor cell interactions, which confer survival advantage and drug resistance. Defining the sequelae of tumor cell interactions within the MM niches on an individualized basis may provide the rationale for personalized therapies. To mimic the MM niche, we here describe a new 3D co-culture ex-vivo model in which primary MM patient BM cells are co-cultured with mesenchymal stem cells (MSC) in a hydrogel 3D system. In the 3D model, MSC with conserved phenotype (CD73+CD90+CD105+) formed compact clusters with active fibrous connections, and retained lineage differentiation capacity. Extracellular matrix molecules, integrins, and niche related molecules including N-cadherin and CXCL12 are expressed in 3D MSC model. Furthermore, activation of osteogenesis (MMP13, SPP1, ADAMTS4, and MGP genes) and osteoblastogenic differentiation was confirmed in 3D MSC model. Co-culture of patient-derived BM mononuclear cells with either autologous or allogeneic MSC in 3D model increased proliferation of MM cells, CXCR4 expression, and SP cells. We carried out immune profiling to show that distribution of immune cell subsets was similar in 3D and 2D MSC model systems. Importantly, resistance to novel agents (IMiDs, bortezomib, carfilzomib) and conventional agents (doxorubicin, dexamethasone, melphalan) was observed in 3D MSC system, reflective of clinical resistance. This 3D MSC model may therefore allow for studies of MM pathogenesis and drug resistance within the BM niche. Importantly, ongoing prospective trials are evaluating its utility to inform personalized targeted and immune therapy in MM. PMID:27764795

Mesenchymal stem cell-based HSP70 promoter-driven VEGFA induction by resveratrol promotes angiogenesis in a mouse model.

PubMed

Chen, Young-Bin; Lan, Ying-Wei; Hung, Tsai-Hsien; Chen, Lih-Geeng; Choo, Kong-Bung; Cheng, Winston T K; Lee, Hsuan-Shu; Chong, Kowit-Yu

2015-07-01

Several studies of stem cell-based gene therapy have indicated that long-lasting regeneration following vessel ischemia may be stimulated through VEGFA gene therapy and/or MSC transplantation for reduction of ischemic injury in limb ischemia and heart failure. The therapeutic potential of MSC transplantation can be further improved by genetically modifying MSCs with genes which enhance angiogenesis following ischemic injury. In the present study, we aimed to develop an approach in MSC-based therapy for repair and mitigation of ischemic injury and regeneration of damaged tissues in ischemic disease. HSP70 promoter-driven VEGFA expression was induced by resveratrol (RSV) in MSCs, and in combination with known RSV biological functions, the protective effects of our approach were investigated by using ex vivo aortic ring coculture system and a 3D scaffolds in vivo model. Results of this investigation demonstrated that HSP promoter-driven VEGFA expression in MSC increased approximately 2-fold over the background VEGFA levels upon HSP70 promoter induction by RSV. Exposure of HUVEC cells to medium containing MSC in which VEGFA had been induced by cis-RSV enhanced tube formation in the treated HUVEC cells. RSV-treated MSC cells differentiated into endothelial-like phenotypes, exhibiting markedly elevated expression of endothelial cell markers. These MSCs also induced aortic ring sprouting, characteristic of neovascular formation from pre-existing vessels, and additionally promoted neovascularization at the MSC transplantation site in a mouse model. These observations support a hypothesis that VEGFA expression induced by cis-RSV acting on the HSP70 promoter in transplanted MSC augments the angiogenic effects of stem cell gene therapy. The use of an inducible system also vastly reduces possible clinical risks associated with constitutive VEGFA expression.

Biomass assessment of microbial surface communities by means of hyperspectral remote sensing data.

PubMed

Rodríguez-Caballero, Emilio; Paul, Max; Tamm, Alexandra; Caesar, Jennifer; Büdel, Burkhard; Escribano, Paula; Hill, Joachim; Weber, Bettina

2017-05-15

Dryland vegetation developed morphological and physiological strategies to cope with drought. However, as aridity increases, vascular plant coverage gets sparse and microbially-dominated surface communities (MSC), comprising cyanobacteria, algae, lichens and bryophytes together with heterotropic bacteria, archaea and fungi, gain relevance. Nevertheless, the relevance of MSC net primary productivity has only rarely been considered in ecosystem scale studies, and detailed information on their contribution to the total photosynthetic biomass reservoir is largely missing. In this study, we mapped the spatial distribution of two different MSC (biological soil crusts and quartz fields hosting hypolithic crusts) at two different sites within the South African Succulent Karoo (Soebatsfontein and Knersvlakte). Then we characterized both types of MSC in terms of chlorophyll content, and combining these data with the biocrust and quartz field maps, we estimated total biomass values of MSCs and their spatial patterns within the two different ecosystems. Our results revealed that MSC are important vegetation components of the South African Karoo biome, revealing clear differences between the two sites. At Soebatsfontein, MSC occurred as biological soil crusts (biocrusts), which covered about one third of the landscape reaching an overall biomass value of ~480gha -1 of chlorophyll a+b at the landscape scale. In the Knersvlakte, which is characterized by harsher environmental conditions (i.e. higher solar radiation and potential evapotranspiration), MSC occurred as biocrusts, but also formed hypolithic crusts growing on the lower soil-immersed parts of translucent quartz pebbles. Whereas chlorophyll concentrations of biocrusts and hypolithic crusts where insignificantly lower in the Knersvlakte, the overall MSC biomass reservoir was by far larger with ~780gha -1 of chlorophyll a+b. Thus, the complementary microbially-dominated surface communities promoted biomass formation within the environmentally harsh Knersvlakte ecosystem. Copyright © 2017 Elsevier B.V. All rights reserved.

Mesenchymal stem cell and regenerative medicine: regeneration versus immunomodulatory challenges

PubMed Central

Law, Sujata; Chaudhuri, Samaresh

2013-01-01

Mesenchymal Stem cells (MSC) are now presented with the opportunities of multifunctional therapeutic approaches. Several reports are in support of their self-renewal, capacity for multipotent differentiation, and immunomodulatory properties. They are unique to contribute to the regeneration of mesenchymal tissues such as bone, cartilage, muscle, ligament, tendon, and adipose. In addition to promising trials in regenerative medicine, such as in the treatment of major bone defects and myocardial infarction, MSC has shown a therapeutic effect other than direct hematopoiesis support in hematopoietic reconstruction. MSCs are identified by the expression of many molecules including CD105 (SH2) and CD73(SH3/4) and are negative for the hematopoietic markers CD34, CD45, and CD14. Manufacturing of MSC for clinical trials is also an important aspect as their differentiation, homing and Immunomodulatory properties may differ. Their suppressive effects on immune cells, including T cells, B cells, NK cells and DC cells, suggest MSCs as a novel therapy for GVHD and other autoimmune disorders. Since the cells by themselves are non-immunogenic, tissue matching between MSC donor and recipient is not essential and, MSC may be the first cell type able to be used as an “off-the-shelf” therapeutic product. Following a successful transplantation, the migration of MSC to the site of injury refers to the involvement of chemokines and chemokine receptors of respective specificity. It has been demonstrated that cultured MSCs have the ability to engraft into healthy as well as injured tissue and can differentiate into several cell types in vivo, which facilitates MSC to be an ideal tool for regenerative therapy in different disease types. However, some observations have raised questions about the limitations for proper use of MSC considering some critical factors that warn regular clinical use. PMID:23671814

Compressive elasticity of three-dimensional nanofiber matrix directs mesenchymal stem cell differentiation to vascular cells with endothelial or smooth muscle cell markers.

PubMed

Wingate, K; Bonani, W; Tan, Y; Bryant, S J; Tan, W

2012-04-01

The importance of mesenchymal stem cells (MSC) in vascular regeneration is becoming increasingly recognized. However, few in vitro studies have been performed to identify the effects of environmental elasticity on the differentiation of MSC into vascular cell types. Electrospinning and photopolymerization techniques were used to fabricate a three-dimensional (3-D) polyethylene glycol dimethacrylate nanofiber hydrogel matrix with tunable elasticity for use as a cellular substrate. Compression testing demonstrated that the elastic modulus of the hydrated 3-D matrices ranged from 2 to 15 kPa, similar to the in vivo elasticity of the intima basement membrane and media layer. MSC seeded on rigid matrices (8-15 kPa) showed an increase in cell area compared with those seeded on soft matrices (2-5 kPa). Furthermore, the matrix elasticity guided the cells to express different vascular-specific phenotypes with high differentiation efficiency. Around 95% of MSC seeded on the 3-D matrices with an elasticity of 3 kPa showed Flk-1 endothelial markers within 24h, while only 20% of MSC seeded on the matrices with elasticity >8 kPa demonstrated Flk-1 marker. In contrast, ∼80% of MSC seeded on 3-D matrices with elasticity >8 kPa demonstrated smooth muscle α-actin marker within 24h, while fewer than 10% of MSC seeded on 3-D matrices with elasticity <5 kPa showed α-actin markers. The ability to control MSC differentiation into either endothelial or smooth muscle-like cells based purely on the local elasticity of the substrate could be a powerful tool for vascular tissue regeneration. Copyright © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

An economical model for simulating droplet spectrum evolution in turbulent cloud chambers and wind tunnels

NASA Astrophysics Data System (ADS)

Krueger, Steven; Cantrell, W.; Niedermeier, D.; Shaw, R.; Stratmann, F.

2017-11-01

Although airborne instruments provide detailed information about the microphysical structure of clouds, the measurements provide only a few snapshots of each cloud. Deducing the droplet spectrum evolution from such measurements is next to impossible. We are using two alternative approaches: laboratory studies and numerical simulations. The former relies on a new turbulent cloud chamber (the Pi Chamber) at Michigan Technical University, as well as the first humid turbulent wind tunnel (LACIS-T) at the Leibniz Institute for Tropospheric Research. Both produce conditions for droplet growth (i.e., supersaturation) by mixing saturated vapor at different temperatures. The Pi Chamber produces turbulence by inducing Rayleigh-Bénard convection, while the wind tunnel generates turbulence with a grid. We are using the Explicit Mixing Parcel Model (EMPM) to numerically simulate droplet spectrum evolution in these flows. The EMPM explicitly links turbulent mixing and droplet spectrum evolution by representing a turbulent flow in a 1D domain with the linear eddy model. The EMPM can economically span scales from those of the smallest turbulent eddies to those of the largest. The EMPM grows or evaporates thousands of individual cloud droplets according to their local environments.

Smoldering News From STS-77 Endeavour

NASA Technical Reports Server (NTRS)

Koudelka, John M.; Fernandez-Pello, A. Carlos

1997-01-01

The Microgravity Smoldering Combustion (MSC) experiment lifted off aboard the Space Shuttle Endeavour for its second flight in May 1996, as part of the STS-77 mission. This experiment is part of a series of studies focused on the smolder characteristics of porous combustible materials in a microgravity environment. Smoldering is a nonflaming form of combustion that takes place in the interior of combustible materials. Common examples of smoldering are nonflaming embers, charcoal briquettes, and cigarettes. The objective of this study is to provide a better understanding of the controlling mechanisms of smoldering in microgravity and normal Earth gravity (1g). As with other forms of combustion, gravity affects the availability of air and transport of heat, and therefore, the rate of combustion. The results of the microgravity experiments will be compared with identical ones carried out in 1g. In addition, they will be used to verify present theories of smolder combustion and will provide new insights into the process of smoldering combustion, enhancing our fundamental understanding of this frequently encountered combustion process and guiding improvements in fire safety practices. Two smoldering combustion tests with polyurethane foam were successfully accomplished during the STS-77 mission. The tests investigated smoldering combustion in a quiescent (no-flow) enriched oxygen environment, and in an air environment with a 2-mm/sec airflow through the fuel sample. The primary data from the tests are the ignition characteristics, spread rate, smolder reaction temperature, and products of combustion (solid and gas). On both the first mission on STS-69 and the second mission on STS-77, a smolder front propagated the length of the forced-flow samples, with the spread rate between the corresponding upward and downward 1g smolder rates. Neither of the quiescent cases propagated combustion (the first case was due in part to a problem with the experiment electronics). These results show a dramatic difference from the normal gravity results, where smolder propagation is very rapid and complete for both of these conditions. The experiment was conceived by Prof. A. Carlos Fernandez-Pello at the University of California-Berkeley. The MSC hardware was designed and built at the NASA Lewis Research Center by a team of civil servants and contractors from NYMA, Inc., and Aerospace Design & Fabrication, Inc. (ADF). The hardware consists of two sealed aluminum combustion chambers (each being a half a cylinder). The chambers hold the MSC test section, data acquisition electronics, power distribution electronics, and instrumentation. The hardware is fitted into a 5-ft(sup 3) Get-Away-Special (GAS) canister that is mounted in the shuttle cargo bay. The test section consists of a quartz cylinder that contains the polyurethane foam sample and an igniter. This igniter, which is an electrically heated wire sandwiched between two porous ceramic disks, is mounted in contact with the end of the foam sample. An array of 12 thermocouples placed axially and radially along the foam sample provide temperature histories, which are used to determine the rate of smolder propagation, and the characteristics of the reaction.

Mesenchymal Stem or Stromal Cells from Amnion and Umbilical Cord Tissue and Their Potential for Clinical Applications

PubMed Central

Lindenmair, Andrea; Hatlapatka, Tim; Kollwig, Gregor; Hennerbichler, Simone; Gabriel, Christian; Wolbank, Susanne; Redl, Heinz; Kasper, Cornelia

2012-01-01

Mesenchymal stem or stromal cells (MSC) have proven to offer great promise for cell-based therapies and tissue engineering applications, as these cells are capable of extensive self-renewal and display a multilineage differentiation potential. Furthermore, MSC were shown to exhibit immunomodulatory properties and display supportive functions through parakrine effects. Besides bone marrow (BM), still today the most common source of MSC, these cells were found to be present in a variety of postnatal and extraembryonic tissues and organs as well as in a large variety of fetal tissues. Over the last decade, the human umbilical cord and human amnion have been found to be a rich and valuable source of MSC that is bio-equivalent to BM-MSC. Since these tissues are discarded after birth, the cells are easily accessible without ethical concerns. PMID:24710543

Template synthesis of hollow MoS2-carbon nanocomposites using microporous organic polymers and their lithium storage properties.

PubMed

Jin, Jaewon; Kim, Bolyong; Kim, Mincheol; Park, Nojin; Kang, Sungah; Lee, Sang Moon; Kim, Hae Jin; Son, Seung Uk

2015-07-14

This work shows that hollow and microporous organic polymers (H-MOPs) are good templating materials for the synthesis of inorganic material-carbon nanocomposites. The precursor compound, (NH4)2MoS4, was incorporated into H-MOPs. Heat treatment under argon resulted in the formation of hollow MoS2-carbon nanocomposites (MSC). According to microscopic analysis, the MoS2 in the MSC has a layered structure with an elongated interlayer distance. The MSC showed high reversible discharge capacities up to 802 mA h g(-1) after 30 cycles and excellent rate performance for lithium ion batteries. The promising electrochemical performance of the MSC is attributed to the very thin and disordered nature of MoS2 in the carbon skeleton. The role of chemical components of the MSC in the electrochemical process was suggested.

Cell-based Therapy for Acute Organ Injury: Preclinical Evidence and On-going Clinical Trials Using Mesenchymal Stem Cells

PubMed Central

Monsel, Antoine; Zhu, Ying-gang; Gennai, Stephane; Hao, Qi; Liu, Jia; Lee, Jae W.

2014-01-01

Critically ill patients often suffer from multiple organ failures involving lung, kidney, liver or brain. Genomic, proteomic and metabolomic approaches highlight common injury mechanisms leading to acute organ failure. This underlines the need to focus on therapeutic strategies affecting multiple injury pathways. The use of adult stem cells such as mesenchymal stem or stromal cells (MSC) may represent a promising new therapeutic approach as increasing evidence shows that MSC can exert protective effects following injury through the release of pro-mitotic, anti-apoptotic, anti-inflammatory and immunomodulatory soluble factors. Furthermore, they can mitigate metabolomic and oxidative stress imbalance. In this work, we review the biological capabilities of MSC and the results of clinical trials using MSC as therapy in acute organ injuries. Although preliminary results are encouraging, more studies concerning safety and efficacy of MSC therapy are needed to determine their optimal clinical use. PMID:25211170

Investigation of Shock Diffusers at Mach Number 1.85. 1 - Projecting Single Shock Cones

DTIC Science & Technology

1947-06-17

cylindrical simulated combustion chamber was used to vary the outlet area of the flow through the diffuser. The pitot -static rake , located as shown in the...Simulated combustion u chamber A 90° W •—Conical damper S Static-pressure orifice ps pitot -static "" rake ’ NATIONAL ADVISORY...recoveries were obtained with subsonic entrance flow. INTRODCJCTION For efficient conversion of the kinetic energy of a supersonic air stream into ram

Brayton Cycle Power System in the Space Power Facility

NASA Image and Video Library

1969-07-21

Set up of a Brayton Cycle Power System test in the Space Power Facility’s massive vacuum chamber at the National Aeronautics and Space Administration’s (NASA) Plum Brook Station in Sandusky, Ohio. The $28.4-million facility, which began operations in 1969, is the largest high vacuum chamber ever built. The chamber is 100 feet in diameter and 120 feet high. It can produce a vacuum deep enough to simulate the conditions at 300 miles altitude. The Space Power Facility was originally designed to test nuclear-power sources for spacecraft, but it was never used for that purpose. The Space Power Facility was first used to test a 15 to 20-kilowatt Brayton Cycle Power System for space applications. Three different methods of simulating solar heat were employed during the tests. Lewis researchers studied the Brayton power system extensively in the 1960s and 1970s. The Brayton engine converted solar thermal energy into electrical power. The system operated on a closed-loop Brayton thermodynamic cycle with a helium-xenon gas mixture as its working fluid. A space radiator was designed to serve as the system’s waste heat rejecter. The radiator was later installed in the vacuum chamber and tested in a simulated space environment to determine its effect on the power conversion system. The Brayton system was subjected to simulated orbits with 62 minutes of sun and 34 minutes of shade.

Environmental fog/rain visual display system for aircraft simulators

NASA Technical Reports Server (NTRS)

Chase, W. D. (Inventor)

1982-01-01

An environmental fog/rain visual display system for aircraft simulators is described. The electronic elements of the system include a real time digital computer, a caligraphic color display which simulates landing lights of selective intensity, and a color television camera for producing a moving color display of the airport runway as depicted on a model terrain board. The mechanical simulation elements of the system include an environmental chamber which can produce natural fog, nonhomogeneous fog, rain and fog combined, or rain only. A pilot looking through the aircraft wind screen will look through the fog and/or rain generated in the environmental chamber onto a viewing screen with the simulated color image of the airport runway thereon, and observe a very real simulation of actual conditions of a runway as it would appear through actual fog and/or rain.

Venturi vacuum systems for hypobaric chamber operations.

PubMed

Robinson, R; Swaby, G; Sutton, T; Fife, C; Powell, M; Butler, B D

1997-11-01

Physiological studies of the effects of high altitude on man often require the use of a hypobaric chamber to simulate the reduced ambient pressures. Typical "altitude" chambers in use today require complex mechanical vacuum systems to evacuate the chamber air, either directly or via reservoir system. Use of these pumps adds to the cost of both chamber procurement and maintenance, and service of these pumps requires trained support personnel and regular upkeep. In this report we describe use of venturi vacuum pumps to perform the function of mechanical vacuum pumps for human and experimental altitude chamber operations. Advantages of the venturi pumps include their relatively low procurement cost, small size and light weight, ease of installation and plumbing, lack of moving parts, and independence from electrical power sources, fossil fuels and lubricants. Conversion of three hyperbaric chambers to combined hyper/hypobaric use is described.

Multiscale computing.

PubMed

Kobayashi, M; Irino, T; Sweldens, W

2001-10-23

Multiscale computing (MSC) involves the computation, manipulation, and analysis of information at different resolution levels. Widespread use of MSC algorithms and the discovery of important relationships between different approaches to implementation were catalyzed, in part, by the recent interest in wavelets. We present two examples that demonstrate how MSC can help scientists understand complex data. The first is from acoustical signal processing and the second is from computer graphics.

Sheet of osteoblastic cells combined with platelet-rich fibrin improves the formation of bone in critical-size calvarial defects in rabbits.

PubMed

Wang, Zhifa; Hu, Hanqing; Li, Zhijin; Weng, Yanming; Dai, Taiqiang; Zong, Chunlin; Liu, Yanpu; Liu, Bin

2016-04-01

Techniques that use sheets of cells have been successfully used in various types of tissue regeneration, and platelet-rich fibrin (PRF) can be used as a source of growth factors to promote angiogenesis. We have investigated the effects of the combination of PRF and sheets of mesenchymal stem cells (MSC) from bone marrow on the restoration of bone in critical-size calvarial defects in rabbits to find out whether the combination promotes bony healing. Sheets of MSC and PRF were prepared from the same donor. We then implanted the combined MSC and PRF in critical-size calvarial defects in rabbits and assessed bony restoration by microcomputed tomography (microCT) and histological analysis. The results showed that PRF significantly increased bony regeneration at 8 weeks after implantation of sheets of MSC and PRF compared with sheets of MSC alone (p=0.0048). Our results indicate that the combination of sheets of MSC and PRF increases bone regeneration in critical-size calvarial defects in rabbits, and provides a new way to improve skeletal healing. Copyright © 2015 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Combination of butylphthalide with umbilical mesenchymal stem cells for the treatment of delayed encephalopathy after carbon monoxide poisoning.

PubMed

Wang, Huanjun; Li, Yan; Wu, Qiang; Xu, Chenglong; Liu, Qingran

2016-12-01

Delayed encephalopathy after carbon monoxide (CO) poisoning (DEACMP) is still a clinical challenge. This study aimed to investigate the efficacy of combined therapy of mesenchymal stem cell (MSC) transplantation and butylphthalide in DEACMP patients.Forty-two DEACMP patients were treated with 1 of the 3 therapies: combined therapy of MSC transplantation and butylphthalide; MSC transplantation alone; or hyperbaric oxygen therapy. The MSCs were alternatively injected into the subarachnoid space and the carotid artery using a self-made high-pressure injector. The Mini-Mental State Examination and the Barthel index of activities of daily living were administered before the treatment, and at 1 month, 3 months, and 6 months after the treatment. Computed tomography and magnetic resonance imaging results before and after the treatment were compared.At 1 month, 3 months, and 6 months after the treatment, the Mini-Mental State Examination scores and the Barthl scores were significantly higher in patients with the combined therapy of MSC transplantation and butylphthalide than those in patients with MSC transplantation alone or hyperbaric oxygen therapy (all P < 0.0001). No significant adverse events occurred.The combination of MSC transplantation and butylphthalide is safe and effective in treating DEACMP.

Genetic Complementation of the Obligate Marine Actinobacterium Salinispora tropica with the Large Mechanosensitive Channel Gene mscL Rescues Cells from Osmotic Downshock

PubMed Central

Bucarey, Sergio A.; Penn, Kevin; Paul, Lauren; Fenical, William

2012-01-01

Marine actinomycetes in the genus Salinispora fail to grow when seawater is replaced with deionized (DI) water in complex growth media. While bioinformatic analyses have led to the identification of a number of candidate marine adaptation genes, there is currently no experimental evidence to support the genetic basis for the osmotic requirements associated with this taxon. One hypothesis is that the lineage-specific loss of mscL is responsible for the failure of strains to grow in media prepared with DI water. The mscL gene encodes a conserved transmembrane protein that reduces turgor pressure under conditions of acute osmotic downshock. In the present study, the mscL gene from a Micromonospora strain capable of growth on media prepared with DI water was transformed into S. tropica strain CNB-440. The single-copy, chromosomal genetic complementation yielded a recombinant Salinispora mscL+ strain that demonstrated an increased capacity to survive osmotic downshock. The enhanced survival of the S. tropica transformant provides experimental evidence that the loss of mscL is associated with the failure of Salinispora spp. to grow in low-osmotic-strength media. PMID:22492446

Design enhancement tools in MSC/NASTRAN

NASA Technical Reports Server (NTRS)

Wallerstein, D. V.

1984-01-01

Design sensitivity is the calculation of derivatives of constraint functions with respect to design variables. While a knowledge of these derivatives is useful in its own right, the derivatives are required in many efficient optimization methods. Constraint derivatives are also required in some reanalysis methods. It is shown where the sensitivity coefficients fit into the scheme of a basic organization of an optimization procedure. The analyzer is to be taken as MSC/NASTRAN. The terminator program monitors the termination criteria and ends the optimization procedure when the criteria are satisfied. This program can reside in several plances: in the optimizer itself, in a user written code, or as part of the MSC/EOS (Engineering Operating System) MSC/EOS currently under development. Since several excellent optimization codes exist and since they require such very specialized technical knowledge, the optimizer under the new MSC/EOS is considered to be selected and supplied by the user to meet his specific needs and preferences. The one exception to this is a fully stressed design (FSD) based on simple scaling. The gradients are currently supplied by various design sensitivity options now existing in MSC/NASTRAN's design sensitivity analysis (DSA).

Cisplatin-induced mesenchymal stromal cells-mediated mechanism contributing to decreased antitumor effect in breast cancer cells.

PubMed

Skolekova, Svetlana; Matuskova, Miroslava; Bohac, Martin; Toro, Lenka; Durinikova, Erika; Tyciakova, Silvia; Demkova, Lucia; Gursky, Jan; Kucerova, Lucia

2016-01-12

Cells of the tumor microenvironment are recognized as important determinants of the tumor biology. The adjacent non-malignant cells can regulate drug responses of the cancer cells by secreted paracrine factors and direct interactions with tumor cells. Human mesenchymal stromal cells (MSC) actively contribute to tumor microenvironment. Here we focused on their response to chemotherapy as during the treatment these cells become affected. We have shown that the secretory phenotype and behavior of mesenchymal stromal cells influenced by cisplatin differs from the naïve MSC. MSC were more resistant to the concentrations of cisplatin, which was cytotoxic for tumor cells. They did not undergo apoptosis, but a part of MSC population underwent senescence. However, MSC pretreatment with cisplatin led to changes in phosphorylation profiles of many kinases and also increased secretion of IL-6 and IL-8 cytokines. These changes in cytokine and phosphorylation profile of MSC led to increased chemoresistance and stemness of breast cancer cells. Taken together here we suggest that the exposure of the chemoresistant cells in the tumor microenvironment leads to substantial alterations and might lead to promotion of acquired microenvironment-mediated chemoresistance and stemness.

Comparison of six bone-graft substitutes regarding to cell seeding efficiency, metabolism and growth behaviour of human mesenchymal stem cells (MSC) in vitro.

PubMed

Seebach, Caroline; Schultheiss, Judith; Wilhelm, Kerstin; Frank, Johannes; Henrich, Dirk

2010-07-01

Various synthetic bone-graft substitutes are used commercially as osteoconductive scaffolds in the treatment of bone defects and fractures. The role of bone-graft substitutes is changing from osteoconductive conduits for growth to an delivery system for biologic fracture treatments. Achieving optimal bone regeneration requires biologics (e.g. MSC) and using the correct scaffold incorporated into a local environment for bone regeneration. The need for an unlimited supply with high quality bone-graft substitutes continue to find alternatives for bone replacement surgery. This in vitro study investigates cell seeding efficiency, metabolism, gene expression and growth behaviour of MSC sown on six commercially clinical available bone-graft substitutes in order to define their biological properties: synthetic silicate-substituted porous hydroxyapatite (Actifuse ABX), synthetic alpha-TCP (Biobase), synthetic beta-TCP (Vitoss), synthetic beta-TCP (Chronos), processed human cancellous allograft (Tutoplast) and processed bovines hydroxyapatite ceramic (Cerabone). 250,000 MSC derived from human bone marrow (n=4) were seeded onto the scaffolds, respectively. On days 2, 6 and 10 the adherence of MSC (fluorescence microscopy) and cellular activity (MTT assay) were analysed. Osteogenic gene expression (cbfa-1) was analysed by RT-PCR and scanning electron microscopy was performed. The highest number of adhering cells was found on Tutoplast (e.g. day 6: 110.0+/-24.0 cells/microscopic field; p<0.05) followed by Chronos (47.5+/-19.5, p<0.05), Actifuse ABX (19.1+/-4.4), Biobase (15.7+/-9.9), Vitoss (8.8+/-8.7) and Cerabone (8.1+/-2.2). MSC seeded onto Tutoplast showed highest metabolic activity and gene expression of cbfa-1. These data are confirmed by scanning electron microscopy. The cell shapes varied from round-shaped cells to wide spread cells and cell clusters, depending on the bone-graft substitutes. Processed human cancellous allograft is a well-structured and biocompatible scaffold for ingrowing MSC in vitro. Of all other synthetical scaffolds, beta-tricalcium phosphate (Chronos) have shown the best growth behaviour for MSC. Our results indicate that various bone-graft substitutes influence cell seeding efficiency, metabolic activity and growth behaviour of MSC in different manners. We detected a high variety of cellular integration of MSC in vitro, which may be important for bony integration in the clinical setting. 2010 Elsevier Ltd. All rights reserved.

Experimental and numerical studies of a microfluidic device with compliant chambers for flow stabilization

NASA Astrophysics Data System (ADS)

Iyer, V.; Raj, A.; Annabattula, R. K.; Sen, A. K.

2015-07-01

This paper reports experimental and numerical studies of a passive microfluidic device that stabilizes a pulsating incoming flow and delivers a steady flow at the outlet. The device employs a series of chambers along the flow direction with a thin polymeric membrane (of thickness 75-250 µm) serving as the compliant boundary. The deformation of the membrane allows accumulation of fluid during an overflow and discharge of fluid during an underflow for flow stabilization. Coupled fluid-structure simulations are performed using Mooney-Rivlin formulations to account for a thin hyperelastic membrane material undergoing large deformations to accurately predict the device performance. The device was fabricated with PDMS as the substrate material and thin PDMS membrane as the compliant boundary. The performance of the device is defined in terms of a parameter called ‘Attenuation Factor (AF)’. The effect of various design parameters including membrane thickness, elastic modulus, chamber size and number of chambers in series as well as operating conditions including the outlet pressure, mean input flow rate, fluctuation amplitude and frequency on the device performance were studied using experiments and simulations. The simulation results successfully confront the experimental data (within 10%) which validates the numerical simulations. The device was used at the exit of a PZT actuated valveless micropump to take pulsating flow at the upstream and deliver steady flow downstream. The amplitude of the pulsating flow delivered by the micropump was significantly reduced (AF = 0.05 for a device with three 4 mm chambers) but at the expense of a reduction in the pressure capability (<20%). The proposed device could potentially be used for reducing flow pulsations in practical microfluidic circuits.

Anthropomorphic cardiac ultrasound phantom.

PubMed

Smith, S W; Rinaldi, J E

1989-10-01

A new phantom is described which simulates the human cardiac anatomy for applications in ultrasound imaging, ultrasound Doppler, and color-flow Doppler imaging. The phantom consists of a polymer left ventricle which includes a prosthetic mitral and aortic valve and is connected to a mock circulatory loop. Aerated tap water serves as a blood simulating fluid and ultrasound contrast medium within the circulatory loop. The left ventricle is housed in a Lexan ultrasound visualization chamber which includes ultrasound viewing ports and acoustic absorbers. A piston pump connected to the visualization chamber by a single port pumps degassed water within the chamber which in turn pumps the left ventricle. Real-time ultrasound images and Doppler studies measure flow patterns through the valves and within the left ventricle.

Method and apparatus for simulating gravitational forces on a living organism

NASA Technical Reports Server (NTRS)

Thornton, W. E. (Inventor)

1983-01-01

A method and apparatus for simulating gravitational forces on a living organism wherein a series of negative pressures are externally applied to successive length-wise sections of a lower limb of the organism. The pressures decreasing progressively with distance of said limb sections from the heart of the organism. A casing defines a chamber adapted to contain the limb of the organism and is rigidified to resist collapse upon the application of negative pressures to the interior of the chamber. Seals extend inwardly from the casing for effective engagement with the limb of the organism and, in cooperation with the limb, subdivide the chamber into a plurality of compartments each in negative pressure communicating relation with the limb.

Documentation of the Recirculation in a Closed-Chamber Rotor Hover Test

NASA Technical Reports Server (NTRS)

McCoy, Miranda; Wadcock, Alan J.; Young, Larry A.

2016-01-01

A rotor hover test was performed inside the JPL 25-foot-diameter Space Simulator. The 40-inch-diameter rotor was tested at two locations in the chamber-on the chamber centerline and 2m off-axis. The rotor was tested in both upright and inverted configurations for 500 < RPM < 2000. Fluorescent tufts were used to identify regions of recirculation. Velocities on the entrainment side of the rotor were measured. Tabulated values for the mean entrainment velocity components and the corresponding root mean square velocity fluctuations are provided. Unsteady velocity measurements provide a description of the turbulence ingested into the rotor plane and quantify the unsteady velocity field that the Mars Scout Helicopter can expect to encounter during free flight inside the Space Simulator.

Messinian Salinity Crisis - DREAM (Deep-sea Record of Mediterranean Messinian events) drilling projects

NASA Astrophysics Data System (ADS)

Lofi, Johanna; Camerlenghi, Angelo

2014-05-01

About 6 My ago the Mediterranean Sea was transformed into a giant saline basin. This event, commonly referred to as the Messinian salinity crisis (MSC), changed the chemistry of the global ocean and had a permanent impact on both the terrestrial and marine ecosystems of a huge area surrounding the Mediterranean area. The first fascinating MSC scenario was proposed following DSDP Leg XIII in 1970 and envisaged an almost desiccated deep Mediterranean basin with a dramatic ~1,500 m drop of sea level, the incision of deep canyons by rivers on the continental margins, and a final catastrophic flooding event when the connections between the Mediterranean Sea and the Atlantic were re-established ~5.33 My ago. In spite of 40 years of multi-disciplinary research conducted on the MSC, modalities, timing, causes, chronology and consequence at local and planetary scale are still not yet fully understood, and the MSC event remains one of the longest-living controversies in Earth Science. Key factor for the controversy is the lack of a complete record of the MSC preserved in the deepest Mediterranean basins. Anywhere else, the MSC mostly generated a sedimentary/time lag corresponding to a widespread erosion surface. Correlations with the offshore depositional units are thus complex, preventing the construction of a coherent scenario linking the outcropping MSC evaporites, the erosion on the margins, and the deposition of clastics and evaporites in the abyssal plains. Recent activity by various research groups in order to identify locations for multiple-site drilling (including riser-drilling) in the Mediterranean Sea that would contribute to solve the open questions still existing about the MSC has culminated in two DREAM Magellan+ Workshops held in 2013 and 2014. A strategy and work plan have been established in order to submit an IODP Multi-phase Drilling Project("Uncovering A Salt Giant")including several site-specific drilling proposals addressing different scientific objectives related to the MSC. Among these proposals, one will be fully dedicated to the MSC event. Improved quality of seismic data has allowed important advances in the recognition and understanding of MSC seismic markers (surfaces and depositional units) and lithological and stratigraphical calibrations are now critical. Therefore, the drilling strategy must include multiple sites covering representative locations of both Western and Eastern Mediterranean basins. A series of critical drilling targets were thus identified as follows: - A first set of drilling targets, dedicated to shallow water (< 2500 m water depth) MSC markers, includes the Messinian clastic wedges, the erosion surfaces and the MSC deposits (including thin salt bodies) trapped in small topographic lows observed at various water depths between the shoreline and the abyssal plain. Up to 10 sites, presented in this work, could be drilled with the riserless R/V Joides Resolution, provided the safety conditions are met; - Another critical drilling target is the full recovering of undeformed MSC sequence (including the Tortonian-Messinian and the Messinian-Zanclean boundaries) in the deep water (>2500m) of both the eastern and western Mediterranean basins. This will be possible thanks to R/V Chikyu riser drilling vessel and will be the scope of a second MSC IODP proposal. DREAM Team: A. Giovanni galod@locean-ipsl.upmc.fr, H. Christian huebscher@zmaw.de, G. deLangeGert gdelange@geo.uu.nl, R. Flecker r.flecker@bristol.ac.uk, D. Garcia-Castellanos danielgc@ictja.csic.es, C. Gorini gorini@upmc.fr, Z. Gvirtzman zohar@gsi.gov.il, W. Krijgsman krijgsma@geo.uu.nl, S. Lugli lugli@unimore.it, I. Makowsky yizhaq@univ.haifa.ac.il, M. Vinicio vinicio.manzi@unipr.it, T. McGenity tjmcgen@essex.ac.uk, G. Panieri giuliana.panieri@uit.no, M. Rabineau rabineau@univ-brest.fr, M. Roveri marco.roveri@unipr.it, F.J. Sierro sierro@usal.es, N. Waldman nwaldmann@univ.haifa.ac.il

Human Mesenchymal Stem Cell Spheroids in Fibrin Hydrogels Exhibit Improved Cell Survival and Potential for Bone Healing

PubMed Central

Murphy, Kaitlin C.; Fang, Sophia Y.; Leach, J. Kent

2014-01-01

Mesenchymal stem cells (MSC) have great therapeutic potential for the repair of nonhealing bone defects due to their proliferative capacity, multilineage potential, trophic factor secretion, and lack of immunogenicity. However, a major barrier to the translation of cell-based therapies into clinical practice is ensuring their survival and function upon implantation into the defect site. We hypothesized that forming MSC into more physiologic 3-dimensional spheroids, rather than employing dissociated cells from 2-dimensional monolayer culture, would enhance their survival when exposed to a harsh microenvironment while maintaining their osteogenic potential. MSC spheroids were formed using the hanging drop method with increasing cell numbers. Compared to larger spheroids, the smallest spheroids which contained 15,000 cells exhibited increased metabolic activity, reduced apoptosis, and the most uniform distribution of proliferating cells. Spheroids were then entrapped in fibrin gels and cultured in serum-free media and 1% oxygen. Compared to identical numbers of dissociated MSC in fibrin gels, spheroids exhibited significantly reduced apoptosis and secreted up to 100-fold more VEGF. We also observed that fibrin gels containing spheroids and those containing an equivalent number of dissociated cells exhibited similar expression levels of early and late markers of osteogenic differentiation. These data demonstrate that MSC spheroids exhibit greater resistance to apoptosis and enhanced proangiogenic potential, while maintaining similar osteogenic potential to dissociated MSC entrapped in a clinically relevant biomaterial, supporting the use of MSC spheroids in cell-based approaches to bone repair. PMID:24781147

A small population of resident limb bud mesenchymal cells express few MSC-associated markers, but the expression of these markers is increased immediately after cell culture.

PubMed

Marín-Llera, Jessica Cristina; Chimal-Monroy, Jesús

2018-05-01

Skeletal progenitors are derived from resident limb bud mesenchymal cells of the vertebrate embryos. However, it remains poorly understood if they represent stem cells, progenitors, or multipotent mesenchymal stromal cells (MSC). Derived-MSC of different adult tissues under in vitro experimental conditions can differentiate into the same cellular lineages that are present in the limb. Here, comparing non-cultured versus cultured mesenchymal limb bud cells, we determined the expression of MSC-associated markers, the in vitro differentiation capacity and their gene expression profile. Results showed that in freshly isolated limb bud mesenchymal cells, the proportion of cells expressing Sca1, CD44, CD105, CD90, and CD73 is very low and a low expression of lineage-specific genes was observed. However, recently seeded limb bud mesenchymal cells acquired Sca1 and CD44 markers and the expression of the key differentiation genes Runx2 and Sox9, while Scx and Pparg genes decreased. Also, their chondrogenic differentiation capacity decreased through cellular passages while the osteogenic increased. Our findings suggest that the modification of the cell adhesion process through the in vitro method changed the limb mesenchymal cell immunophenotype leading to the expression and maintenance of common MSC-associated markers. These findings could have a significant impact on MSC study and isolation strategy because they could explain common variations observed in the MSC immunophenotype in different tissues. © 2018 International Federation for Cell Biology.

Transgelin is a TGFβ-inducible gene that regulates osteoblastic and adipogenic differentiation of human skeletal stem cells through actin cytoskeleston organization

PubMed Central

Elsafadi, M; Manikandan, M; Dawud, R A; Alajez, N M; Hamam, R; Alfayez, M; Kassem, M; Aldahmash, A; Mahmood, A

2016-01-01

Regenerative medicine is a novel approach for treating conditions in which enhanced bone regeneration is required. We identified transgelin (TAGLN), a transforming growth factor beta (TGFβ)-inducible gene, as an upregulated gene during in vitro osteoblastic and adipocytic differentiation of human bone marrow-derived stromal (skeletal) stem cells (hMSC). siRNA-mediated gene silencing of TAGLN impaired lineage differentiation into osteoblasts and adipocytes but enhanced cell proliferation. Additional functional studies revealed that TAGLN deficiency impaired hMSC cell motility and in vitro transwell cell migration. On the other hand, TAGLN overexpression reduced hMSC cell proliferation, but enhanced cell migration, osteoblastic and adipocytic differentiation, and in vivo bone formation. In addition, deficiency or overexpression of TAGLN in hMSC was associated with significant changes in cellular and nuclear morphology and cytoplasmic organelle composition as demonstrated by high content imaging and transmission electron microscopy that revealed pronounced alterations in the distribution of the actin filament and changes in cytoskeletal organization. Molecular signature of TAGLN-deficient hMSC showed that several genes and genetic pathways associated with cell differentiation, including regulation of actin cytoskeleton and focal adhesion pathways, were downregulated. Our data demonstrate that TAGLN has a role in generating committed progenitor cells from undifferentiated hMSC by regulating cytoskeleton organization. Targeting TAGLN is a plausible approach to enrich for committed hMSC cells needed for regenerative medicine application. PMID:27490926

Dasatinib and Doxorubicin Treatment of Sarcoma Initiating Cells: A Possible New Treatment Strategy.

PubMed

Aggerholm-Pedersen, Ninna; Demuth, Christina; Safwat, Akmal; Meldgaard, Peter; Kassem, Moustapha; Sandahl Sorensen, Boe

2016-01-01

Background. One of the major challenges affecting sarcoma treatment outcome, particularly that of metastatic disease, is resistance to chemotherapy. Cancer-initiating cells are considered a major contributor to this resistance. Methods. An immortalised nontransformed human stromal (mesenchymal) stem cell line hMSC-TERT4 and a transformed cell line hMSC-TERT20-CE8, known to form sarcoma-like tumours when implanted in immune-deficient mice, were used as models. Receptor tyrosine kinase (RTK) activation was analysed by RTK arrays and cellular viability after tyrosine kinases inhibitor (TKI) treatment with or without doxorubicin was assessed by MTS assay. Results. Initial results showed that the hMSC-TERT4 was more doxorubicin-sensitive while hMSC-TERT20-CE8 was less doxorubicin-sensitive evidenced by monitoring cell viability in the presence of doxorubicin at different doses. The epidermal growth factor receptor (EGFR) was activated in both cell lines. However hMSC-TERT20-CE8 exhibited significantly higher expression of the EGFR ligands. EGFR inhibitors such as erlotinib and afatinib alone or in combination with doxorubicin failed to further decrease cell viability of hMSC-TERT20-CE8. However, inhibition with the TKI dasatinib in combination with doxorubicin decreased cell viability of the hMSC-TERT20-CE8 cell line. Conclusion. Our results demonstrate that dasatinib, but not EGFR-directed treatment, can decrease cell viability of stromal cancer stem cells less sensitive to doxorubicin.

Cartilage repair using mesenchymal stem cell (MSC) sheet and MSCs-loaded bilayer PLGA scaffold in a rabbit model.

PubMed

Qi, Yiying; Du, Yi; Li, Weixu; Dai, Xuesong; Zhao, Tengfei; Yan, Weiqi

2014-06-01

The integration of regenerated cartilage with surrounding native cartilage is a major challenge for the success of cartilage tissue-engineering strategies. The purpose of this study is to investigate whether incorporation of the power of mesenchymal stem cell (MSC) sheet to MSCs-loaded bilayer poly-(lactic-co-glycolic acid) (PLGA) scaffolds can improve the integration and repair of cartilage defects in a rabbit model. Rabbit bone marrow-derived MSCs were cultured and formed cell sheet. Full-thickness cylindrical osteochondral defects (4 mm in diameter, 3 mm in depth) were created in the patellar groove of 18 New Zealand white rabbits and the osteochondral defects were treated with PLGA scaffold (n = 6), PLGA/MSCs (n = 6) or MSC sheet-encapsulated PLGA/MSCs (n = 6). After 6 and 12 weeks, the integration and tissue response were evaluated histologically. The MSC sheet-encapsulated PLGA/MCSs group showed significantly more amounts of hyaline cartilage and higher histological scores than PLGA/MSCs group and PLGA group (P < 0.05). In addition, the MSC sheet-encapsulated PLGA/MCSs group showed the best integration between the repaired cartilage and surrounding normal cartilage and subchondral bone compared to other two groups. The novel method of incorporation of MSC sheet to PLGA/MCSs could enhance the ability of cartilage regeneration and integration between repair cartilage and the surrounding cartilage. Transplantation of autologous MSC sheet combined with traditional strategies or cartilage debris might provide therapeutic opportunities for improving cartilage regeneration and integration in humans.

How to Hit Mesenchymal Stromal Cells and Make the Tumor Microenvironment Immunostimulant Rather Than Immunosuppressive

PubMed Central

Poggi, Alessandro; Varesano, Serena; Zocchi, Maria Raffaella

2018-01-01

Experimental evidence indicates that mesenchymal stromal cells (MSCs) may regulate tumor microenvironment (TME). It is conceivable that the interaction with MSC can influence neoplastic cell functional behavior, remodeling TME and generating a tumor cell niche that supports tissue neovascularization, tumor invasion and metastasization. In addition, MSC can release transforming growth factor-beta that is involved in the epithelial–mesenchymal transition of carcinoma cells; this transition is essential to give rise to aggressive tumor cells and favor cancer progression. Also, MSC can both affect the anti-tumor immune response and limit drug availability surrounding tumor cells, thus creating a sort of barrier. This mechanism, in principle, should limit tumor expansion but, on the contrary, often leads to the impairment of the immune system-mediated recognition of tumor cells. Furthermore, the cross-talk between MSC and anti-tumor lymphocytes of the innate and adaptive arms of the immune system strongly drives TME to become immunosuppressive. Indeed, MSC can trigger the generation of several types of regulatory cells which block immune response and eventually impair the elimination of tumor cells. Based on these considerations, it should be possible to favor the anti-tumor immune response acting on TME. First, we will review the molecular mechanisms involved in MSC-mediated regulation of immune response. Second, we will focus on the experimental data supporting that it is possible to convert TME from immunosuppressive to immunostimulant, specifically targeting MSC. PMID:29515580

Microenvironment mesenchymal cells protect ovarian cancer cell lines from apoptosis by inhibiting XIAP inactivation

PubMed Central

Castells, M; Milhas, D; Gandy, C; Thibault, B; Rafii, A; Delord, J-P; Couderc, B

2013-01-01

Epithelial ovarian carcinoma is characterized by high frequency of recurrence (70% of patients) and carboplatin resistance acquisition. Carcinoma-associated mesenchymal stem cells (CA-MSC) have been shown to induce ovarian cancer chemoresistance through trogocytosis. Here we examined CA-MSC properties to protect ovarian cancer cells from carboplatin-induced apoptosis. Apoptosis was determined by Propidium Iodide and Annexin-V-FITC labelling and poly-ADP-ribose polymerase cleavage analysis. We showed a significant increase of inhibitory concentration 50 and a 30% decrease of carboplatin-induced apoptosis in ovarian cancer cells incubated in the presence of CA-MSC-conditioned medium (CM). A molecular analysis of apoptosis signalling pathway in response to carboplatin revealed that the presence of CA-MSC CM induced a 30% decrease of effector caspases-3 and -7 activation and proteolysis activity. CA-MSC secretions promoted Akt and X-linked inhibitor of apoptosis protein (XIAP; caspase inhibitor from inhibitor of apoptosis protein (IAP) family) phosphorylation. XIAP depletion by siRNA strategy permitted to restore apoptosis in ovarian cancer cells stimulated by CA-MSC CM. The factors secreted by CA-MSC are able to confer chemoresistance to carboplatin in ovarian cancer cells through the inhibition of effector caspases activation and apoptosis blockade. Activation of the phosphatidylinositol 3-kinase (PI3K)/Akt signalling pathway and the phosphorylation of its downstream target XIAP underlined the implication of this signalling pathway in ovarian cancer chemoresistance. This study reveals the potentialities of targeting XIAP in ovarian cancer therapy. PMID:24176845

The effect of stem cell from human exfoliated deciduous teeth on T lymphocyte proliferation.

PubMed

Alipour, Razieh; Adib, Minoo; Hashemi-Beni, Batool; Sadeghi, Farzaneh

2014-01-01

Mesenchymal stem cells (MSC), a specific type of adult tissue stem cell; have the immunosuppressive effects that make them valuable targets for regenerative medicine and treatment of many human illnesses. Hence, MSC have been the subject of numerous studies. The classical source of MSC is adult bone marrow (BM). Due to many shortcomings of harvesting MSC from BM, finding the alternative sources for MSC is an urgent. Stem cells from human exfoliated deciduous teeth (SHED) are relative new MSC populations that fulfill these criteria but their potential immunosuppressive effect has not been studied enough yet. Thus, in this work the effect of SHED on the proliferation of in vitro activated T lymphocytes were explored. In this study, both mitogen and alloantigen activated T cells were cultured in the presence of different numbers of SHED. In some co-cultures, activated T cells were in direct contact to MSCs and in other co-cultures; they were separated from SHED by a permeable membrane. In all co-cultures, the proliferation of T cells was measured by ELISA Bromodeoxyuridine proliferation assay. In general, our results showed that SHED significantly suppress the proliferation of activated T cells in a dose-dependent manner. Moreover, the suppression was slightly stronger when MSCs were in physical contact to activated T cells. This study showed that SHED likewise other MSC populations can suppress the activation of T lymphocytes, which can be used instead of BM derived MSCs in many investigational and clinical applications.

In Situ Fiber-Optic Reflectance Monitor

NASA Technical Reports Server (NTRS)

Linton, Roger C.; Gray, Perry A.

1996-01-01

In situ fiber-optic reflectance monitor serves as simple means of monitoring changes in reflectance of specimen exposed to simulated outerspace or other environments in vacuum chamber. Eliminates need to remove specimen from vacuum chamber, eliminating optical changes and bleaching such removal causes in coatings.

IDENTIFICATION OF AN IDEAL REACTOR MODEL IN A SECONDARY COMBUSTION CHAMBER

EPA Science Inventory

Tracer analysis was applied to a secondary combustion chamber of a rotary kiln incinerator simulator to develop a computationally inexpensive networked ideal reactor model and allow for the later incorporation of detailed reaction mechanisms. Tracer data from sulfur dioxide trace...

Apollo 16 astronauts in Apollo Command Module Mission Simulator

NASA Image and Video Library

1972-03-14

S72-31047 (March 1972) --- Astronaut Thomas K. Mattingly II (right foreground), command module pilot of the Apollo 16 lunar landing mission, participates in extravehicular activity (EVA) training in Building 5 at the Manned Spacecraft Center (MSC). Mattingly is scheduled to perform EVA during the Apollo 16 journey home from the moon. Astronaut John W. Young, commander, can be seen in the left background. In the right background is astronaut Charles M. Duke Jr., lunar module pilot. They are inside the Apollo Command Module Mission Simulator. While Mattingly remains with the Apollo 16 Command and Service Modules (CSM) in lunar orbit, Young and Duke will descend in the Lunar Module (LM) to the moon's Descartes landing site.

Characterization of air temperature in modern ion chambers due to phantom geometry and ambient temperature changes.

PubMed

Saenz, Daniel L; Kirby, Neil; Gutiérrez, Alonso N

2016-07-01

Temperature and pressure corrections are necessary to account for the varying mass of air in the sensitive volume of a vented ionization chamber (IC) when performing absolute dose measurements. Locations commonly used to measure the presumed IC air temperature may not accurately represent the chamber cavity air temperature, and phantoms undergoing temperature changes further compound the problem. Prior studies have characterized thermal equilibrium in separate phantoms for Farmer chambers alone. However, the purpose of this study was to characterize the cavity air temperature dependence on changes in the ambient temperature and phantom geometry configuration for a wider and more modern variety of chambers to determine if previously published wait times apply to these chambers as well. Thermal conduction properties were experimentally investigated by modifying a PTW 0.3 cm(3) Semiflex IC with a thermocouple replacing the central electrode. Air cavity temperature versus time was recorded in three phantom geometries characteristic of common absolute dose measurements. The phantoms were (15 ± 1) °C before measurement with an IC at the treatment vault temperature of (21 ± 1) °C. Simulations were conducted to provide a theoretical basis for the measurements and to simulate temperature response of a PTW PinPoint® and Farmer chamber. The simulation methods were first validated by comparison with measured Semiflex chamber thermal response curves before extension to the other chambers. Two thermal equilibria curves were recorded on different time scales. IC temperature initially dropped to the colder phantom temperature but subsequently increased as the phantom itself equilibrated with the warmer room temperature. In a large phantom of dimensions (25.5 × 25.5 × 23.4) cm(3), 3 min was required before the IC temperature reached within 0.5 °C of its equilibrium within the phantom. Similarly, wait times of 2 min were needed for 7.5 and 2 cm slab phantoms. Recording of temperature in the phantom was deemed far more accurate than measurement in ambient air due to the air cavity thermally equilibrating with phantom temperature instead of the vented ambient air. Wait times of 3 and 2 min are needed for a cube and 7.5 cm slab phantom, respectively, to achieve 0.2% dosimetric accuracy (temperature accuracy of 0.5 °C). Chamber volume alone did not determine wait times, as a 0.3 cm(3) IC required a longer wait time than a Farmer chamber, suggesting wall thickness as an important variable as well.

Characteristics of Perforated Diffusers at Free-Stream Mach Number 1.90

DTIC Science & Technology

1950-05-08

deg) Subscripts: 0 free stream 1 inlet entrance 2 Inlet throat 3 pitot -static rake in simulated combustion chamber 4 outlet of simulated...consisted of a 40-tube pitot -static survey rake located 0.55 combust Ion-chamber diameter downstream of the outlet of the subsonic diffuser (fig. 8(b...The rake was so designed that eaoh pitot -static tube was located at the oentroid of one of the forty equal area segments Into which the combustion

Force and Moment Plots from Pacejka 2002 Magic Formula Tire Model Coefficients

DTIC Science & Technology

2010-09-01

Page Form ApprovedOMB No. 0704-0188 Public reporting burden for the collection of information is estimated to average 1 hour per response, including...failing to comply with a collection of information if it does not display a currently valid OMB control number. 1 . REPORT DATE 10 SEP 2010 2. REPORT...forces and moments applied to the tires. Many vehicle simulation programs such as MSC.Software ADAMS, Altair HyperWorks MotionSolve, etc. use the Magic

Investigating the Mobility of Light Autonoumous Tracked Vehicles Using a High Performance Computing Simulation Capability

DTIC Science & Technology

2012-08-01

UNCLASSIFIED: Distribution Statement A. Approved for public release. DISCLAIMER: Reference herein to any specific commercial company , product...FunctionBay, S. Korea – NVIDIA – Caterpillar – MSC.Software – Advanced Micro Devices (AMD) 14-16 AUG 2012  Aaron Bartholomew  Makarand Datar...16GB DDR2 Graphics: 4x NVIDIA Tesla C1060 Power supply 1: 1000W Power supply 2: 750W Assembled Quad GPU Machine 14-16 AUG 2012 30

Neural-Network-Development Program

NASA Technical Reports Server (NTRS)

Phillips, Todd A.

1993-01-01

NETS, software tool for development and evaluation of neural networks, provides simulation of neural-network algorithms plus computing environment for development of such algorithms. Uses back-propagation learning method for all of networks it creates. Enables user to customize patterns of connections between layers of network. Also provides features for saving, during learning process, values of weights, providing more-precise control over learning process. Written in ANSI standard C language. Machine-independent version (MSC-21588) includes only code for command-line-interface version of NETS 3.0.