LONDON (Dow Jones)--JPMorgan Mid Cap Investment Trust PLC (JMF.LN) said Friday it purchased into treasury 55,000 ordinary shares at 378.9 pence per share. -Shares closed Friday at 369.5 pence. -By Iain Packham, Dow Jones Newswires; 44-20-7842-9269; [email protected] (END) Dow Jones Newswires June 25, 2010 12:06 ET (16:06 GMT)