What happens if I use Professor [Juniper] and have less than 7 cards left in my deck? Do I lose immediately, or do I draw out the remainder of my deck and lose at the beginning of my next turn (if I don't do anything to replenish the deck like Recycle, Mr.Fuji,
You only lose when you don't have any cards to draw on; the card draw you must do on the start of your turn. So you would lose on your next turn if you didn't somehow get some cards back into your [draw] deck.
Source: WotC Chat (2000-08-03)