in samples not visibly stained with fetal blood , the ratio of the acetylcholinesterase density to the pseudocholinesterase density distinguished between open ventral-wall defects and open neural-tube defects : the former group all had values less than 0.13 , while the latter all had values greater than that .
C0001044
acetylcholinesterase
C0008429
pseudocholinesterase