Rome, August 16 - Further study is needed on ex-premier Silvio Berlusconi's bid to retain his Senate seat, under threat since Italy's highest appeal court has upheld his criminal fraud conviction, Gaetano Quagliariello said Friday. "I think there are many things to clarify and deepen, and I think it is in everyone's interest to do so," the constitutional reform minister, a leading member of Berlusconi's People of Freedom (PdL) party, said in an interview with ANSA. The situation does not have "predetermined outcomes," he added, because of the political sensitivity and consequences of the situation. Italy's fragile coalition government has been threatened by political fighting over the recent high-court ruling. Some members of the centre-left Democratic Party (PD) say they cannot work with a party led by a convicted criminal, while members of the PdL want broad government support in forcing a pardon for Berlusconi and protection of his Senate seat. Next month, Italy's upper house will vote on whether to strip Berlusconi of his Senate seat because of his criminal conviction.