European Factors to Watch-Shares buoyed by Nasdaq high, Greek optimism

LONDON, April 24 (Reuters) - European shares were set to rise at the open on Friday, extending gains made so far this week, with sentiment lifted by a new record high for the blue-chip Nasdaq index. Traders also cited optimism that Greece would be able to reach a debt deal with its European lenders after German Chancellor Angela Merkel said she had a "constructive" meeting with Greek Prime Minister Alexis Tsipras. Financial spreadbetters expected Britain's FTSE 100 to open 21 points hig