22 research outputs found
In vivo magnetic resonance imaging of mesenchymal stem cells in myocardial infarction
Background - We investigated the potential of magnetic resonance imaging (MRI) to track magnetically labeled mesenchymal stem cells (MR-MSCs) in a swine myocardial infarction (MI) model. Methods and Results - Adult farm pigs (n=5) were subjected to closed-chest experimental MI. MR-MSCs (2.8 to 16×107 cells) were injected intramyocardially under x-ray fluoroscopy. MRIs were obtained on a 1.5T MR scanner to demonstrate the location of the MR-MSCs and were correlated with histology. Contrast-enhanced MRI demonstrated successful injection in the infarct and serial MSC tracking was demonstrated in two animals. Conclusion - MRI tracking of MSCs is feasible and represents a preferred method for studying the engraftment of MSCs in MI
MR-trackable intramyocardial injection catheter
There is growing interest in delivering cellular agents to infarcted myocardium to prevent postinfarction left ventricular remodeling. MRI can be effectively used to differentiate infarcted from healthy myocardium. MR-guided delivery of cellular agents/therapeutics is appealing because the therapeutics can be precisely targeted to the desired location within the infarct. In this study, a steerable intramyocardial injection catheter that can be actively tracked under MRI was developed and tested. The components of the catheter were arranged to form a loopless RF antenna receiver coil that enabled active tracking. Feasibility studies were performed in canine and porcine myocardial infarction models. Myocardial delayed-enhancement (MDE) imaging identified the infarcted myocardium, and real-time MRI was used to guide left ventricular catheterization from a carotid artery approach. The distal 35 cm of the catheter was seen under MRI with a bright signal at the distal tip of the catheter. The catheter was steered into position, the distal tip was apposed against the infarct, the needle was advanced, and a bolus of MR contrast agent and tissue marker dye was injected intramyocardially, as confirmed by imaging and post-mortem histology. A pilot study involving intramyocardial delivery of magnetically labeled stem cells demonstrated the utility of the active injection catheter system. © 2004 Wiley-Liss, Inc
Recommended from our members
Mechanical design for neutral beam injection
At the Lawrence Livermore and Berkeley Laboratories two major neutral beam system designs were developed, the High Voltage Test Stand (HVTS) and a conceptual system for the Two Component Tokamak-Toroidal Fusion Test Reactor (TCT- TFTR). The HVTS was designed for flexibility in performing a wide variety of tests, while the TCT-TFTR beam line was designed to satisfy particular requirements for target-plasma operation. Both designs make use of condensation cryopumping to handle very high gas loads. The HVTS design involves high-voltage isolation techniques of cryogenic and other systems. The TCT-TFTR design requires optimization of pumping and other systems. It is to be expected that experience gained from design and operation of the HVTS systems will be of value to the final design of TCT-TFTR and to the engineering of future fusion reactors. (auth
Recommended from our members
Some considerations of materials requirements for mirror fusion reactors
Recommended from our members
MFTF vacuum vessel and cryopumping system
The Mirror Fusion Test Facility (MFTF) vacuum vessel and cryopumping system have attracted considerable interest within the fusion research community. Their extreme size, coupled with severe performance requirements and unique design features, justifies this interest. The planned expansion of the system to a tandem mirror configuration with thermal barriers further increases the engineering challenges of this complex facility
Recommended from our members
Neutral beam injection system for the Tokamak Fusion Test Reactor
The Tokamak Fusion Test Reactor will be installed at the Princeton Plasma Physics Laboratory facility. This is a major step to reach the goal of fusion power using toroidal magnetic fields for plasma confinement. A major part of this test reactor will be four neutral beam injection systems. These systems will inject 20 MW of 120 kV neutral deuterium atoms into the plasma for 0.5 seconds. In order to achieve the required power input to the plasma, several systems are required within the neutral beam line. These are the source, neutralizer, ion deflection magnet, calorimeter and retraction system, ion dump, cryopumps and vacuum enclosure. All of these systems have constraints imposed which increase the complexity of their designs. Since all systems must operate in a tritium environment, remote handling capabilities must be incorporated into the design. An overview is presented of the Lawrence Livermore Laboratory/Lawrence Berkeley Laboratory Neutral Beam Injection System design. Specifications for the machine and a general description of the total system are presented
Recommended from our members
Final design of the neutral beam lines for the Tokamak Fusion Test Reactor
Final design of the neutral beam lines for TFTR has been completed. A prototype has been assembled at Lawrence Berkeley Laboratory and is undergoing testing as part of the Neutral Beam System Test Facility (NBSTF). The final neutral beam line (NBL) configuration differs in several details from that previously reported upon; certain components have been added; and testing of the cryopump system has led to some design simplification. It is these developments which are reported herein
Recommended from our members
Cryopump, neutral-beam compatibility test
The design and performance testing plan for a cryopump to be used on the TFTR neutral beams injectors are briefly discussed. The cryopump consists of an outer envelope at liquid nitrogen temperature, and an inner envelope at liquid helium temperature. In the cryopanel-chevron structure to be tested, a deuterium condensation rate of 2.5 x 10/sup 4/ liters/s is predicted. A three phase test plan for performance testing at both LBL and LLL is delineated. (RME