Dec 15 (Reuters) - GBST Holdings Ltd GBT.AX :
* Appointment of CEO & chairman GBT.AX
* Says robert de dominicis appointed managing director and CEO
* Says john puttick has decided to retire from the board after 31 years as chairman of GBST
* Says allan brackin to succeed john puttick as chairman
* Source text for Eikon ID:nASXbvs5gJ