Biomedical subjects

Feng Xie

Publications and source records attributed to Feng Xie.

39 records · Page 3Linked to original sources

PubMed1997

Differences in Myocardial Contrast Produced with Transient Response Imaging When Using Intravenous Microbubbles Containing Gases of Different Molecular Weight.

The purpose of this study was to determine the effect of different microbubble gases on the amount of myocardial contrast (MC) produced from intravenously (IV) injected dextrose albuinin microbubbles when using a new imaging modality termed transient response imaging (TRI). In 6 dogs (4 closed chest, 2 open chest) the peak anterior myocardial videointensity (PMVI) and visual degree of MC were determined following IV injections of equivalent doses of perfluorocarbon exposed sonicated dextrose albumin (PESDA), sulfur hexafluoride-exposed sonicated dextrose albumin (SHESDA), and room air exposed sonicated dextrose albumin (RASDA) microbubbles. TRI was performed by triggering ultrasound impulses to 1 point every one to two cardiac cycles. The PMVI produced with TRI was compared to conventional 30 Hz frame rate imaging (CI) for each gas. Visual anterior and posterior MC was evident with TRI in all six dogs using PESDA, but not in any dog with CI. Although RASDA and SHESDA did not produce MC with CI, visually evident anterior MC was seen after 7 of 8 SHESDA and 4 of 9 RASDA injections when using TRI with both gases. PESDA produced the highest peak PMVI of all three microbubbles when using TRI, while SHESDA produced a significantly higher PMVI than RASDA. We conclude that although MC can be produced with TRI using microbubble gases of lower molecular weight, the brightest and most consistent contrast is produced with fluorocarbon containing microbubbles.

Journal Article↗

PubMedDate not supplied

Targeted vascular delivery of antisense molecules using intravenous microbubbles.

OBJECTIVE: Perfluorocarbon-exposed sonicated dextrose albumin (PESDA) microbubbles bind the antisense to the c-myc protooncogene (anti-c-myc) which prevents neointimal hyperplasia following vascular endothelial injury. The microbubbles also adhere to sites of damaged vascular endothelium and thus may be a method of systemically targeting delivery of anti-c-myc. METHODS: Laser scanning microscopy was performed on the aorta of 10 mice (five which were complement depleted) that received intravenous FITC-PESDA following aortic endothelial injury. C-myc expression was quantified following selective intracoronary injury in nine pigs that received intravenous (IV) anti-c-myc bound to PESDA. Finally, neointimal formation was measured following intracoronary stent deployment in 30 pigs that received either IV anti-c-myc alone or the same dose bound to PESDA. RESULTS: Fluorescent microscopy confirmed selective PESDA microbubble adherence to aortic endothelium in all mice with aortic injury. This binding was nearly abolished when serum complement was depleted prior to injury. C-myc expression at the site of coronary endothelial injury was significantly lower in pigs treated with systemic anti-c-myc bound to PESDA. There was a 33% reduction in % stenosis and a 28% reduction in intimal area at 45 days post-stent deployment in pigs that received IV antisense plus PESDA. The stent margins also had reduced neointimal formation. CONCLUSION: Systemic administration of anti-c-myc bound to PESDA microbubbles may be a good method for preventing coronary neointimal formation within and around implanted stents.

Analysis of Variance↗

PubMedDate not supplied

Systemic targeted delivery of antisense with perflourobutane gas microbubble carrier reduced neointimal formation in the porcine coronary restenosis model.

HYPOTHESIS: The antisense phosphorodiamidate morpholino oligomer (PMO), AVI-4126, has been effective in reducing neointimal formation in animal models following delivery by pluronic gels, local delivery catheters and coated stents. Greater flexibility of repeated-dosage regimens and reduced procedure complexity may be provided by systemic injection of AVI-4126 bound to perfluorobutane gas microbubble carriers. The purpose of this study was to investigate the effects of perfluorocarbon gas microbubble carrier (PGMC)-based systemic delivery of AVI-4126 on expression of the c-myc in vascular tissue and restenosis after stent implantation. METHODS: Seven pigs underwent stent implantation (3 stents/animal). Five pigs received IV injection of PGMC and 2 mg of AVI-4126 (AVI BioPharma). Two served as control. Four hours postprocedure, 3 pigs were sacrificed and stented segments analyzed by high-performance liquid chromatography (HPLC) and Western blot. In chronic experiments, 4 pigs (12 stent sites) were sacrificed at 28 days. RESULTS: HPLC analysis of plasma samples of treated animals showed minimal presence of AVI-4126. HPLC of the treated arteries demonstrated easily detected concentrations of AVI-4126. Western blot analysis of the stented vessels demonstrated modest inhibition of c-myc. Morphometry showed that the neointimal area was significantly reduced in the AVI-4126/PGMC group compared with control (2.63+/-1.99 vs. 4.77+/-.1.71 mm2, respectively, P<.05). CONCLUSION: In the porcine coronary stent model, systemic targeted delivery of AVI-4126 using PGMC carrier significantly inhibited neointimal formation.

Animals↗