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Biomedical subjects

P Termin

Publications and source records attributed to P Termin.

5 recordsLinked to original sources
PubMed2001

Histopathologic evaluation of a new dermal allograft following explantation.

BACKGROUND: Numerous materials have been used to accomplish soft tissue augmentation, but the ideal implant remains elusive. Dermaplant is a recently introduced soft tissue matrix derived from human cadaveric dermis and intended for use in soft tissue reconstruction. This product is U.S. Food and Drug Administration (FDA) approved, but there is a paucity of data regarding its clinical performance. OBJECTIVE: To report histopathologic findings of an explanted Dermaplant specimen. METHODS: A healthy 52-year-old man underwent repair of postblepharoplasty eyelid retraction and a prominent tear trough defect. At the patient's request the tear trough implant was removed in the seventh postoperative week. Gross and microscopic evaluations were performed. RESULTS: Fibroblastic infiltration and new collagen production were demonstrated within the implant and at its periphery. Occasional macrophages and giant cells were also noted around the implant. CONCLUSION: In this patient the Dermaplant was well tolerated and supported ingrowth of host tissues. The behavior of this material over the long-term cannot be extrapolated from this study.

Biocompatible Materials↗
PubMed1999

The Carbomedics "Oxford" Photofix stentless valve (PSV).

The hemodynamic superiority of first-generation stentless xenografts over their stented equivalents is now clearly defined. Issues of durability remain. In light of considerable early experience, we sought to provide an "ideal" stentless valve design with the potential for improved durability by eliminating glutaraldehyde. The Carbomedics Oxford Photofix stentless valve (PSV) is a composite xenograft root constructed from three selected porcine noncoronary cusps fixed by the photofix process. The valve inflow has a low pericardial cuff. Consequently there are no coronaries, cloth, or muscle bar in the structure. The valve was tested in the descending aorta and subcoronary positions of juvenile sheep to compare the influence on calcification of photofixation and the alpha-amino-oleic-acid-treated Freestyle valve. There was a substantial difference between the valves, both in radiographic imaging of calcification and the elemental analysis of calcium and phosphorus. In the valve cusp, calcium content of PSV was 3.98+/-5.77 mg/g versus 14.3+/-19.29 mg/g for the Freestyle valve. Equivalent calcium values for the aortic wall were 1.99+/-3.39 mg/g versus 130.79+/-56.29 mg/g. We consider the composite root configuration without cloth, coronaries, or muscle bar to be a promising valve design. The photofix process minimizes xenograft tissue calcification and appears superior to existing methods.

Animals↗
PubMed1991

Intraluminal ultrasound assessment of vascular stent deployment.

This study assessed the utility of intraluminal ultrasound imaging during deployment of a self-expanding vascular stent and quantitated changes in arterial morphology produced by the stent. Cross-sectional images of arterial lumens (n = 50) were obtained before stenting, in-vitro (n = 35) from formalin-preserved human superficial femoral arteries and in-vivo (n = 15) from canine iliac arteries containing laser-induced eccentric stenoses. Comparison of ultrasound-derived vessel dimensions (minimum and maximum diameter and cross-sectional area) with histological morphometric analysis of corresponding vessel sites showed good correlation by linear regression analysis (r = 0.930-0.987, p = 0.001-0.005). Following stent placement, 23 intraluminal ultrasound images were obtained from the stented vessel sites (in-vitro n = 15, in-vivo n = 8) and were compared to prestented cross-sectional areas. In the in-vitro vessels there was a small increase (p = 0.023) in area, but there was no change in the in-vivo arteries (p = 0.6). To assess the effect of stenting on luminal shape (ellipticity), minimum/maximum diameter ratios were compared before and after stent deployment. There was an increase in this ratio in the in-vitro vessels (p = 0.001) but no change in the in-vivo arteries (p = 0.2). We conclude that intraluminal ultrasound produces clear and accurate images of the location, shape and degree of arterial pathology, ensuring good stent: vessel size matching and immediate quantitative assessment of the effects of arterial stent placement.

Animals↗
PubMed1991

Modification of the thrombogenicity of a self-expanding vascular stent.

When placed in the iliac arteries of normal healthy animals, the Wall-stent self-expanding endovascular prosthesis exhibits minimal thrombogenicity, measured by 111In-labeled platelet uptake. Preliminary clinical reports suggest a greater thrombogenicity in diseased human arteries. When evaluated in an ex vivo shunt, these stents exhibit significant thrombogenicity. The ex vivo shunt may therefore provide a model to evaluate strategies to reduce thrombogenicity in the clinical setting. Stents were released into shunts and the uptake of In111-labeled platelets was measured by gamma imaging for 2 h at a flow rate of 100 mL/min. The effect of systemic heparin, 100 U/kg, oral aspirin, 325 mg, and local application of heparin-benzalkonium chloride complex were evaluated. At the end of each study the stents were fixed in situ and evaluated with scanning electron microscopy (SEM). Control stents exhibited a rapid, significant uptake of platelet associated 111In activity, which reached a maximum in approximately 1 h. Twenty-two percent of control stents occluded before 2 h. Aspirin reduced maximum platelet uptake by 46%. Systemic heparin, with a clotting time greater than five times control, reduced maximum platelet uptake by 86%. The benzalkonium-heparin complex coating, with no increase in clotting time, reduced maximum platelet uptake by 84%. No occlusions were observed with the anti-thrombotic regimes. SEM evaluation of the stents supports the results of the isotope uptake studies.

Animals↗