[Experimental tracheal transplantation. Literature review and proposal of an original surgical technique]. / Il trapianto sperimentale di trachea. Revisione della letteratura e proposta di tecnica originale.

The reconstruction of the trachea after wide resections remains a critical surgical problem. Our aim has been to replace trachea with a tissue easy to be vascularized, that permits a simple reconstruction, not requiring an immunosuppressive regimen. We have used a segment of cryopreserved aorta. In the first phase the thoracic aorta of 10 rabbits was excised obtaining 20 segments that were cryopreserved. Ten segments were implanted in the omentum of 10 rabbits that were sacrificed on postoperative day 7, 14 and 21. The histologic examination of the grafts showed the presence of neovascularization after 7 days with obliteration of the lumen by fibroblasts after 14 days. In the next phase the cryopreserved aorta replace an excised segment of trachea. The survived animals were sacrificed 7 and 14 days after the operation. The histologic examination showed the neovascularization of the graft and the absence of rejection.

Triadic discrimination testing: refinement of Thurstonian and sequential sensitivity analysis approaches.

The effect of cognitive search strategies and variations in the oral environment on discrimination test performance were investigated. Subjects were required to discriminate between low concentration NaCl solutions and water using the 3-AFC and triangle test protocols. As predicted by Thurstonian modeling, subjects obtained a higher proportion of correct tests for the 3-AFC protocol than for the triangle protocol. The d' values obtained from both protocols corresponded. As predicted by the Sequential Sensitivity Analysis Model, which is largely based on changes in the oral environment, subjects obtained a higher proportion of correct tests for triads containing one NaCl stimulus than for triads containing one water stimulus. Measurement of physical signal strengths of the stimuli, by analysing the Na cation concentration change in the oral environment on tasting, indicated that the classical Thurstone-Ura two-distribution model was insufficient. The strong carry-over effects in the chemical senses require a model based on more than two distributions. It was also noted that subjects did not always use the search strategy required for a given test protocol. The artifactual effects of strategy change during an experiment are discussed.