Comparison of the durability of cadaveric and autologous fascia using an in vivo model.

OBJECTIVES: To assess the durability of both autologous and cadaveric fascia using an animal model. The pubovaginal sling procedure can be performed using autologous, cadaveric, or synthetic materials. Few data are available about the strength and durability of these materials. METHODS: Rectus abdominus fascia harvested from 6 female Sprague-Dawley rats was processed by Tutogen Medical. In 20 female Sprague-Dawley rats, three different types of fascia were implanted subcutaneously into each animal: autologous rectus abdominus fascia harvested at the time of surgery; rat cadaveric fascia processed by Tutogen; and human cadaveric fascia (Tutogen). The rats were killed at 2 months (10 rats) and 4 months (10 rats) after implantation. The mechanical properties of the tissue were assessed using the trouser tear test, and the fracture toughness was calculated. RESULTS: Compared with the fracture toughness before implantation, the implanted rat autologous fascia decreased in toughness from 1763 to 1243 J/m(2) (P = 0.12), the implanted rat cadaveric fascia decreased in toughness from 1539 to 1022 J/m(2) (P = 0.02), and the implanted human cadaveric fascia decreased in toughness from 2120 to 1145 J/m(2) (P = 0.09). The fracture toughness of the implanted rat cadaveric fascia and rat autologous fascia did not differ significantly (P = 0.29). CONCLUSIONS: The changes in strength or elasticity can be detected using the trouser tear test to calculate the fracture toughness. Both cadaveric and autologous fascial grafts may decrease in toughness with time. The long-term durability of the graft may only be a minor factor in determining the success of the pubovaginal sling procedure.

An in vivo Comparative Study of Intersegmental Flexibility in the Ophiuroid Arm.

We present the first in vivo measurements of intersegmental rotation in the ophiuroid arm, comparing lateral bending performance in seven epifaunal species from Discovery Bay, Jamaica. The species studied include suspension-feeders, deposit-feeders, and scavengers, and also represent two major types of vertebral ossicle morphology. Animals were photographed with strobe illumination, and the angular deflections between arm segments were recorded. Despite considerable variation in vertebral morphology, ecology, and behavior, Discovery Bay ophiuroids show similar, overlapping distributions of maximal intersegmental rotations. Although interspecific differences in mean lateral flexibility can be statistically significant, absolute differences among species are small and of unknown functional significance. These quantitative data challenge long-standing assumptions about how the ophiuroid vertebral skeleton affects intersegmental flexibility, and how intersegmental flexibility per se affects an ophiuroid's ecological style or success.

The 1996 Lindberg Award. Calcium antagonists alter cell shape and induce procollagenase synthesis in keloid and normal human dermal fibroblasts.

Fibroblast cytomorphology is tightly coupled to phenotypic expression, particularly as it relates to extracellular matrix protein synthesis and degradation. We have observed that calcium antagonists, such as verapamil and trifluoperazine, depolymerize actin filaments and alter fibroblast cell shape from bipolar to spherical. Characteristically, the depolymerization of actin filaments, which mediates the cell shape change, turns on procollagenase gene expression in normal human skin fibroblasts. We have found the same effects of calcium antagonists on cell shape, cytoskeletal components, and induction of procollagenase in the keloid fibroblasts of three cell lines, CB792, CW792, and WT949. Rounded cells were seen in 74.8% of verapamil-treated and 86.7% of trifluoperazine-treated cells, whereas only 1.1% of the control cells were spherical. The percentage of cells that synthesized collagenase in the control, verapamil-treated, and trifluoperazine-treated groups was 3.8%, 42.8%, and 53.4%, respectively. Approximately 60% of rounded cells exhibited increased collagenase synthesis when the cells were treated with a calcium antagonist. These results indicate considerable heterogeneity in the phenotypic response to morphologic change. The amount of procollagenase synthesized in a cell was estimated by the fluorescence intensity of the fluorescein-labeled antibody. The normalized fluorescence intensity of procollagenase in the control cells was about 2 to 2.6 times that of background. In contrast, the normalized fluorescence intensity of procollagenase in the calcium antagonist-treated cells was about 2.4 to 12 times that of background. This high intensity level indicates an increase in procollagenase production in the calcium antagonist-treated cells. Calcium green dye used to study cytosolic calcium revealed that after cells were treated with verapamil, the cytosolic calcium ion concentration first increased and then decreased. The change of cytosolic calcium ion concentration may be related to the depolymerization of actin filaments and the alteration of cell shape.