At first, poor East German medic becomes an academic researcher (7)
I believe the answer is:
postdoc
'an academic researcher' is the definition.
'at first poor east german medic' is the wordplay.
'at first' indicates taking the first letters.
'east german' becomes 'ost' ('east' in German).
'medic' becomes 'doc' (I've seen this before).
The first letter of 'poor' is 'p'.
'p'+'ost'+'doc'='POSTDOC'
'becomes' acts as a link.
(Other definitions for postdoc that I've seen before include "Researcher" , "Someone doing advanced research" .)