Problems in nomenclature of bone marrow cells and culture terms

[verhelpe]

Could anyone please tell me :

1) Is osteoprogenitor and osteogenic cells the same cell ?

2) Who comes from the IOPC (indetermined osteoprogenitor cells)?

Where can I find then ?

3) Is bone-like nodules and clusters  positifs 

for mineralization the same thing ?

4) What is split 1:1, 1:2, ... ?

Thanks


Michel