Biomaterial Database

Improved cryoprotection and freeze-substitution of embryonic quail retina: a TEM study on ultrastructural preservation. 1990

D H Meissner, and H Schwarz

Max-Planck-Institut für Entwicklungsbiologie, Tübingen, Federal Republic of Germany.

Conditions for cryofixation and freeze-substitution crucial to the ultrastructural preservation of embryonic quail retina were improved. As freeze-substitution makes gentle dehydration and chemical fixation of tissue possible, the suitability of different cryoprotectants were tested in the preceding cryofixation. Additionally, different conditions for chemical prefixation were studied. In cryofixation, all of the "classic" cryoprotectants caused more or less severe tissue destruction. Only dimethylformamide (DMF) and--with certain reservations--dimethylsulfoxide (DMSO) yielded improved structure preservation. Perfusion fixation with a mixture of formaldehyde/glutaraldehyde (FA/GA) was superior to GA alone. In comparison to conventional fixation and dehydration methods, freeze-substitution yielded better ultrastructural preservation of the embryos with fewer artifacts.

UI	MeSH Term	Description	Entries
D008854	Microscopy, Electron	Microscopy using an electron beam, instead of light, to visualize the sample, thereby allowing much greater magnification. The interactions of ELECTRONS with specimens are used to provide information about the fine structure of that specimen. In TRANSMISSION ELECTRON MICROSCOPY the reactions of the electrons that are transmitted through the specimen are imaged. In SCANNING ELECTRON MICROSCOPY an electron beam falls at a non-normal angle on the specimen and the image is derived from the reactions occurring above the plane of the specimen.	Electron Microscopy
D011784	Quail	Common name for two distinct groups of BIRDS in the order GALLIFORMES: the New World or American quails of the family Odontophoridae and the Old World quails in the genus COTURNIX, family Phasianidae.	Quails
D012160	Retina	The ten-layered nervous tissue membrane of the eye. It is continuous with the OPTIC NERVE and receives images of external objects and transmits visual impulses to the brain. Its outer surface is in contact with the CHOROID and the inner surface with the VITREOUS BODY. The outer-most layer is pigmented, whereas the inner nine layers are transparent.	Ora Serrata
D005612	Freeze Drying	Method of tissue preparation in which the tissue specimen is frozen and then dehydrated at low temperature in a high vacuum. This method is also used for dehydrating pharmaceutical and food products.	Lyophilization,Drying, Freeze,Dryings, Freeze,Freeze Dryings,Lyophilizations
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia