Manufacturing and microscopical characterisation of polyurethane nerve guidance channel featuring a highly smooth internal surface.

The present study demonstrates the possibility of manufacturing polyurethane [ChronoFlex (CF)] nerve guidance channels (NGCs) featuring a highly smooth internal surface. Comparative SEM and AFM observations prove marked differences between the internal surface microgeometry of Silastic and CF channels. SEM of CF samples shows a surface with no detectable roughness, while Silastic channels show transversal rows along the entire surface. AFM digital image of Silastic samples show a surface with a rough microgeometry defined by a tridimensional pattern with peaks up to 1400 nm. AFM digital image of CF samples show, indeed, an essentially flat microgeometry with the highest level at 545 nm. These preliminary results suggest that the association of an innovative sequential deposition manufacturing technique with the new CF polyurethane may produce NGCs with a smoother surface microgeometry, in comparison to NGCs obtained from commercial Silastic tubes.

[Effect of surgical stress on TSH and on the extra-thyroid metabolism of T4 (preliminary experiment)]. / Effetto dello stress chirurgico sul TSH e sul metabolismo extratiroideo della T4 (esperienza preliminare).

The effect of the surgery on the TSH and on the extra thyroid T4 metabolism was studied in thirty euthyroid patients. The TSH showed a light increase thirty minutes after the skin cut. There were no remarkable changes of T4 serum levels, while the serum triiodothyronine concentration fell during and after the operation, with a concomitant rise in reverse triiodothyronine.

[Effect of metoclopramide on growth hormone (GH) release induced with ACTH]. / Effetto della metoclopramide sulla liberazione di GH indotta dall'ACTH.

We examined 10 volunteers subjects, sound and exempt from endocrine disease. The rapid injection of 0,25 mg of ACTH (Synacten) was followed by a distinct increase of plasma Growth Hormone (GH) within 30 or 60 min in 9 of 10 normal volunteers. The test were then repeated in the 12 "responders" after previous subministration of Metoclopramide and the GH response was totally abolished.

[Effect of TRH on growth hormone (GH) release induced with ACTH]. / Effetto del TRH sulla liberazione del GH indotta dall'ACTH.

We examined 14 volunteers subjects sound and exempt from en docrine disease. The rapid injection of 0,25 mg of ACTH (Synacten) was followed by a distinct increase of plasma Hormone (GH) within 30 or 60 min in 12 of 14 normal volunteers. The test were the 12 "responders after previous subministration of 200 g of TRH and the GH response was totally abolished.