QUADRATIC B-MODE AND PULSE INVERSION IMAGING OF THERMALLY-INDUCED LESIONS IN VIVO

2007 ◽  
Author(s):  
Emad Ebbini ◽  
John Bischof ◽  
Rachana Visaria ◽  
Ajay Shrestha
Keyword(s):  
Thermally Induced ◽  
Pulse Inversion ◽  
Pulse Inversion Imaging

scholarly journals Small-Diameter Vessels Reconstruction Using Cell Tissue-Engineering Graft Based on the Polycaprolactone

2021 ◽  
Author(s):  
N. M. Yudintceva ◽  
Yu. A. Nashchekina ◽  
M. A. Shevtsov ◽  
V. B. Karpovich ◽  
G. I. Popov ◽  
...  
Keyword(s):  
Cell Monolayer ◽  
Small Diameter ◽  
Superparamagnetic Iron Oxide ◽  
Biomechanical Properties ◽  
Histological Evaluation ◽  
Endothelial Lining ◽  
Thermally Induced ◽  
Cell Tissue ◽  
Aorta Replacement

Abstract Polycaprolactone (PCL) is widely applied for the construction of small-diameter tissue-engineered vascular grafts (TEGs) due to its biomechanical properties, slow degradation, and good biocompatibility. In the present study the TEG based on a tubular scaffold seeded with smooth muscle aortic cells (SMCs) in a rat abdominal aorta replacement model was tested. Polyester tubular scaffolds were generated by thermally induced phase separation and seeded with rat SMCs. To track the implanted SMCs in vivo, cells were labeled with superparamagnetic iron oxide nanoparticles (SPIONs). Histological evaluation of the migration of autologous endothelial cells (ECs) and formation of the endothelial lining was performed 4, 8, and 12 weeks after graft interposition. TEG demonstrated a high patency rate without any complications at the end of the 12-week period. The migration of ECs into the lumen of the implanted TEG and formation of the cell monolayer were already present at 4 weeks, as confirmed by histological analysis. The architecture of both neointima and neoadventitia were similar to those of the native vessel. SPION-labeled SMCs were detected throughout the TEG, indicating the role of these cells in the endothelization of scaffolds. The SMC-seeded scaffolds demonstrated improved patency and biointegrative properties when compared to the acellular grafts.

453 Pulse inversion imaging — A new technology for improving endocardial definition

1999 ◽  
Vol 1 ◽  
pp. S75-S75
Author(s):  
J COOKE ◽  
J HANCOCK ◽  
D KLOTSA ◽  
D PATSOURAS ◽  
M MONAGHAN
Keyword(s):  
New Technology ◽  
Pulse Inversion ◽  
Pulse Inversion Imaging

Development of a thermally responsive peptide for sustained deliver of solyble TNF receptor II to attenuate inflammatory events associated with radiculopathys

2007 ◽  
Vol 30 (4) ◽  
pp. 94
Author(s):  
Mohammed F. Shamji ◽  
Odelia Ghodsizadeh ◽  
Allan H. Friedman ◽  
William J. Richardson ◽  
Ashutosh Chilkoti ◽  
...  
Keyword(s):  
Phase Transition ◽  
Fusion Protein ◽  
Lumbar Disc ◽  
Tnf Receptor ◽  
Thermally Induced ◽  
Thermally Responsive ◽  
Glutamate Production ◽  
Endotoxin Content

Background: Tumor necrosis factor alpha (TNFα) is a cytokine that may mediate inflammatory histopathology of the dorsal root ganglion following lumbar disc herniation.1 Soluble TNF receptor II (sTNFRII) competitively binds TNFa with clinical value for painful radiculopathy.2 Bioactive peptides expressed with elastin-like polypeptides (ELP) fusion partners gain a thermally responsive domain, by which they can undergo hydrophobic collapse and separate from solution to aggregate at physiological temperatures.3 Protein release from such a depot may locally sustain drug presence, an effect demonstrated for non-fusion ELP after intra-articular injection.4 Methods: We expressed sTNFRII fused to ELP to demonstrate potential bidomain functionality. Protein Expression. A gene encoding ELP-(VPGVG)60 was subcloned adjacent to the sTNFRII and transformed into E.coli for expression.5 Protein Safety. Endotoxin content of purified fusion protein was evaluated using a limulus amebocyte lysate endpoint assay and compared to non-fusion ELP using a two-tailed Student’s t-test. Thermal Responsiveness. Dynamic light scattering evaluated the inverse thermal phase transition behaviour of ELP-sTNFRII, and absorbance spectrophotometry quantified the in vitro depot release at 37°C. Fusion Domain Function. Anti-TNFα bioactivity was assessed by the in vitro inhibition of TNFα-induced glutamate production by microglia. Single-factor ANOVA analyzed treatment differences for ELP-sTNFRII, commercial sTNFRII (positive control), and non-fusion ELP (negative control). A 44 kDa recombinant fusion protein was expressed from E. coli and purified by inverse transition cycling. Results: Measured endotoxin content for ELP-sTNFRII was comparable to ELP alone (p < 0.01), well below FDA levels for biomedical implants. The fusion protein underwent a thermally-induced phase transition and formed observable aggregates of ~240 nm upon heating to physiological temperatures (Tt = 32°C). Slow release was observed from this depot with a time constant of 21 ± 3 hours. The fusion protein demonstrated anti-TNFα activity in vitro by attenuating TNFα-induced microglial glutamate production, albeit requiring a greater concentration than the free antagonist to achieve the same effect.(p < 0.01). Conclusion: Fusion of a sTNFRII protein to an ELP can serve to generate a thermally-induced drug depot that may sustain anti-cytokine activity of agents delivered locally to a nerve region. Further directions may involve studying in vivo biodistribution after perineural delivery of ELP and in vivo disease modifying activity of this agent.

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