when DIG probes go bad

[Kathleen Gajewski]

I have a tinman DIG probe (cRNA) that has worked beautifully until 
recently.  Now I get higher background, and while I get decent mesodermal 
staining in the early stages, I can't get the late heart staining 
anymore.  When the probes go bad, do they just abruptly stop working?  Or 
is there a gradual loss of resolution like I think I'm seeing with mine?  
The probe is less then a year old, and I've been working with dilutions 
from my main batch.  Thank you for any answers you can give me.

					Kathleen Gajewski