Quantitative MR imaging study of intravitreal sustained release of VEGF in rabbits.

Purpose: To determine whether sustained elevation of vascular endothelial growth factor (VEGF) in the vitreous cavity causes retinal hyperpermeability [blood-retinal barrier (BRB) breakdown] before the development of retinal neovascularization (NV) and to document the kinetics of the integrity of BRB breakdown versus time.

Methods: Poly(L-lactide-co-glycolide)based devices loaded with VEGF were implanted intravitreally in rabbit eyes. Contrast-enhanced magnetic resonance imaging (MRI) methods were used to identify and quantitate the retinal permeability at various time points after implantation.

Tissue reactions to polypyrrole-coated polyesters: A magnetic resonance relaxometry study.

The electrically conductive properties of polypyrrole (PPy) as a coating on polyester material are very attractive for the manufacture of small diameter blood conduits. However, before these PPy-coated materials can be investigated for their capacity to generate endothelialized luminal surfaces, they must first be studied for their innocuousness in a living environment. The specific goal of the present study was to investigate the in vivo interactions of PPy-coated and noncoated woven polyester materials implanted subcutaneously in rats for prescheduled periods of 2, 5, 10, 20, and 30 days.

Multinuclear solid-state NMR spectroscopy of envelopes from virgin and explanted silicone breast prostheses: an exploratory study.

The structure and dynamics of silicone envelopes from virgin and explanted breast prostheses have been studied by 1H, 13C, and 29Si high-resolution solid-state NMR spectroscopy. The results indicate that this combination of techniques can be used to unambiguously identify the presence of methyltrifluoropropylsiloxane units and diphenylsiloxane units at concentrations of about 2.0% and 3.

Will it be feasible to insert endoprostheses under interventional MRI?

Purpose: Recent advances in magnetic resonance imaging (MRI) technology may provide a safer and more sensitive monitoring modality than X-ray imaging for endovascular surgical procedures. The purpose of this study was to investigate the feasibility of using MRI to monitor the insertion of endoprostheses.

Methods: The endoprostheses we studied were composed of a nitinol stent encased in a polyester sheath.

High resolution solid-state 29Si NMR spectroscopy of silicone gels used to fill breast prostheses.

We have used 29Si solid-state nuclear magnetic resonance (NMR) spectroscopy to study the chemical structure of the silicone gels in virgin and explanted breast prostheses. Despite evidences of alteration in the morphological appearance of the silicone gel inside the breast prosthesis, our results do not reveal changes in the chemical nature and structure of the silicone gels after implantation. In addition to the main 29Si resonance peak at -22.