The objective of this research was to characterize the percutaneous absorption of the organophosphorous pesticide, malathion, across the skin of bullfrogs (Rana catesbeiana) and marine toads (Bufo marinus) using in vitro models. An established mammalian model for percutaneous absorption, the two-compartment Teflon flow-through diffusion cell assay, was adapted to anuran skin to examine species and anatomical site differences in absorption and partitioning of C<sup>14</sup>-radiolabeled malathion. Malathion absorption was greater across the ventral skin compared to dorsal skin in both bullfrogs and marine toads but did not differ significantly between species. The issue of short-term storage and viability of anuran skin for diffusion cells was examined using glycerol preservation and cryopreservation techniques. Bullfrog skin viability was retained for 28 days, while marine toad skin viability significantly decreased after 7-10 days. A novel in vitro model, the harvested perfused anuran limb (HPAPL) preparation, which maintained an intact microvasculature to the skin, was developed. The HPAPL represented an improvement over diffusion cells by retaining the anatomic and physiologic integrity of the skin. Doppler ultrasound was used to determine the perfusion rate for the HPAPL by measuring the physiologic blood flow of the pelvic limb in vivo. In addition to the characterization of the percutaneous absorption of malation in anurans, effects of sublethal doses on brain acetyl cholinesterase activity in bullfrogs and marine toads, were examined using a modified Ellman spectrophotometric technique. Sensitivity to environmental toxins make anurans potentially important animal models for studying the impacts of organophosphorous insecticide contamination of the environment.
| Identifer | oai:union.ndltd.org:NCSU/oai:NCSU:etd-11022005-110637 |
| Date | 09 November 2005 |
| Creators | Willens, Scott |
| Contributors | Andrew D. Wallace, Sharon K. Taylor, Craig V. Sullivan, Gregory A. Lewbart, Michael K. Stoskopf, Ronald E. Baynes |
| Publisher | NCSU |
| Source Sets | North Carolina State University |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://www.lib.ncsu.edu/theses/available/etd-11022005-110637/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to NC State University or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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