Michael A. Samphilipo

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Quantitative, single-voxel proton NMR spectroscopy of normal brain was performed in five adult beagle dogs using the cerebral water signal as an internal intensity reference. The same brain regions were then rapidly isolated and frozen using a pneumatic biopsy drill, perchloric acid extracted, and analyzed by biochemical assay and high-resolution NMR(More)
PURPOSE This study observes the histologic changes resulting from a hydrogel embolic agent (polyacrylonitrile [PAN]) compared with polyvinyl alcohol particles (PVA) of similar size. MATERIALS AND METHODS Hepatic and renal embolizations were performed in 13 domestic swine by selecting small (1-mm) branches utilizing a coaxial 3-F microcatheter. The(More)
RATIONALE AND OBJECTIVES Structural/functional relationships in an induced canine brain tumor were studied using proton-magnetic resonance spectroscopy (1H-MRS), positron emission tomography (PET), and histology. METHODS Proton-MRS and PET data of implanted canine brain tumors were correlated with quantitative analysis of the tissue composition within the(More)
PURPOSE To evaluate the histopathologic effects of the Tempo-filter, a temporary caval filter, on the caval wall and determine the feasibility of deployment and removal of the device in swine. MATERIALS AND METHODS Filters were placed in the infrarenal inferior vena cava of 11 swine. The tethering catheter was sutured in a subcutaneous pocket near the(More)
To study venous injury caused by a prototype percutaneous mechanical thrombolytic device. Simulated thrombolysis was performed using the device, or the Fogarty balloon catheter (FBC) as control, in the infrarenal inferior vena cava (IVC) of 40 New Zealand white rabbits. Venous injury was evaluated by cavography, Evans blue dye staining, and histology at 0,(More)
PURPOSE To assess the safety and efficacy of redilation of central venous stents in a growing animal model. MATERIALS AND METHODS Palmaz stents were placed in the inferior vena cava (IVC) in 18 newborn lambs. After 5 months, vena cavography was performed. Those animals in which growth of the IVC adjacent to the stent and/or neointimal hyperplasia had(More)
PURPOSE To compare the primary patency of two structurally different metallic stents in an animal model of hemodialysis access grafts. MATERIAL AND METHODS Nineteen synthetic femorofemoral arteriovenous shunts were created in 10 dogs. After a 1-month period of maturation (during which one graft thrombosed), stents were placed spanning the venous(More)
RATIONALE AND OBJECTIVES Spheres of hydrogel have been developed as embolic material with the ability to incorporate radio-opaque materials. To optimize particle design for radiographic or fluoroscopic visualization, we have examined the theoretical determinants of particle contrast. In addition, loaded hydrogel particles were tested in a rabbit model. (More)
A simple, reliable and inexpensive subcutaneously implanted reservoir-catheter system method was developed for repeated sterile access to the rabbit brain ventricular system. The system provides an avenue for the repeated intrathecal administration of drugs and for the withdrawal of cerebrospinal fluid (CSF). Reservoirs were subcutaneously implanted under(More)
A technique for producing a reliable, clinically applicable, and highly reproducible canine model of nonocclusive mesenteric ischemia was developed. Following left thoracotomy in 10 dogs, a 1 mm diameter soft polyethylene tube was inserted into the pericardial space via a small puncture site. This tube was sealed in place with cyanoacrylate tissue adhesive.(More)