S Thermes | PubMed Health

PubMed1999

Instruments for endoscopic endonasal transsphenoidal surgery.

TECHNIQUE: Endoscopic transsphenoidal surgery. New, developing, minimally invasive technique. Removal of pituitary lesions and tumors of the parasellar region. TECHNICAL DEVELOPMENT: Endoscopic endonasal transsphenoidal surgery. Endonasal, not transnasal, procedure. Great respect of anatomy. Very wide surgical field, without intraoperative use of a nasal speculum, but with less room in which to work (only one nostril) and potential conflict between the surgeon's hands and the endoscope (both when entering the nostril and while working inside). INSTRUMENTATION: New instrument. Secure grip. Barycenter of the instrument is the surgeon's hands. Many different tips with different functions. Elimination of the bayonet-like shape. Handle bent in the horizontal plane to avoid interference with the surgeon's hands and to allow the distal, thin part of the instrument to be used safely and comfortably.

Endoscopes↗

PubMed1997

Signaling events following the interaction of the neuronal adhesion molecule F3 with the N-terminal domain of tenascin-R.

Interaction between the extracellular matrix protein tenascin-R and the neuronal adhesion molecule F3 might be involved in the formation of neuronal networks. In this study, the fragment of tenascin-R comprising epithelial growth factor (EGF)-like repeats and the cysteine-rich NH2 terminal stretch (EGF-L), known to be inhibitory for growing neurites and repellent for growth cones, was used to investigate the signaling events following the F3/EGF-L interaction. We addressed this question using an in vitro test with F3-transfected Chinese hamster ovary (CHO) cells that allowed us to measure the kinetics, magnitude and specificity of the repellent effect resulting from the specific F3/EGF-L interaction. We showed that the repellent effect was counteracted by addition of the serine/threonine kinase and -phosphatase modulators (staurosporine, okadaic acid and H7) but not by modulators of tyrosine kinase or -phosphatases. This result indicates that the intracellular signals activated by the repellent effect involve a serine/threonine kinase pathway. Furthermore, the repellent effect of the EGF-L fragment for growth cones of cultured cerebellar neurons was also abolished by the identical modulators of serine/threonine kinase and -phosphatases. The inhibition of neurite outgrowth from hippocampal neurons by EGF-L was abolished in the presence of the serine threonine-kinase inhibitor H7. These results strongly suggest that the F3/tenascin-R interaction through EGF-L involves an intracellular activation of serine/ threonine kinase(s) in all F3-expressing cells tested.

Animals↗