Presence of thyroid hormones in ascidian larvae and their involvement in metamorphosis.

In this study we investigated the presence and localization of thyroxine in Ciona intestinalis larvae and its involvement in metamorphosis. To date, the mechanisms regulating the metamorphosis of ascidians remain largely unknown. In vivo treatment of swimming larvae with exogenous L-thyroxine and thiourea, and in vitro experiments utilizing high performance liquid chromatography, radioimmunoassay, and immunoperoxidase staining demonstrate the presence of thyroxine at the larval stage. This suggests that this hormone may participate in the control of metamorphosis and thus play a different role from that observed in adults.

[Our experience in the surgical treatment of pharyngoesophageal diverticula]. / La nostra esperienza nel trattamento chirurgico dei diverticoli faringo-esofagei.

The authors review a consecutive series of 7 pharyngo-oesophageal diverticula surgically treated from 1979 to 1994. In their opinion, surgery of diverticula to be effective must be preceded by dynamic and functional studies to outline the motor impairment often associated. Surgical indications and the different surgical techniques are also emphasized.