How about this one, I freeze mouse aortas and have difficulty maintaining orientation when placed in liquid nitrogen or methyl butane. I have used the dry ice method by putting some OCT in the cassette, place it on a piece of dry ice till the OCT starts to freeze then orientate the aorta and finish freezing in the cryostat. So far I haven't heard any complaints but has anyone got other suggestions?

Betsy Molinari  HT ASCP

Texas Heart Institute

Houston, Texas

832-355-6524