Premium
Preservation of shock‐frozen myocardial tissue as shown by cryo‐ultramicrotomy and freeze‐fracture studies
Author(s) -
Sætersdal T. S.,
Røli J.,
Myklebust R.,
Engedal H.
Publication year - 1977
Publication title -
journal of microscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.569
H-Index - 111
eISSN - 1365-2818
pISSN - 0022-2720
DOI - 10.1111/j.1365-2818.1977.tb00070.x
Subject(s) - slush , coolant , liquid nitrogen , quenching (fluorescence) , materials science , drill , microtome , brass , composite material , chemistry , copper , metallurgy , optics , physics , organic chemistry , nuclear physics , fluorescence
SUMMARY Myocardial tissue was quickly quench‐frozen by letting the specimen fall either into liquid nitrogen (LN 2 ) or into LN 2 ‐slush, or, by drill‐propelling the specimen into LN 2 at a speed of 1·5 m/s. The preservation of the tissues was studied in ultra‐thin, dry‐cut and freeze‐dried cryo‐sections. Shock‐freezing by propelling into LN 2 yields extensive areas of well preserved tissue without hole damage. Quenching into LN 2 ‐slush shows variable results, while a maximum of hole damage is obtained by letting the specimen fall into LN 2 . Replicas of freeze‐fractured tissue which had been quench‐frozen by the same methods confirmed these observations. By the drill‐propelling, areas 2000–5000 μm 2 wide reveal good preservation without visible ice crystals. Such areas occur within a superficial band of tissue to a depth of c. 20 μm. Even at 35 μm and 50 μm depth good preservation may be registered at the periphery of the replicas. Description is given of modifications in accessories and methods in order to make the LKB CryoKit more suitable as a routine instrument. These modifications cover replacement of the knife coolant container by a coolant brass container in open connection with three copper tubes, replacement of one of the LKB Dewar flasks by a 25 litre Dewar equipped with a Balzers filling device, and replacement of the LKB plastic sleeve fixed to the back of the specimen coolant container, by two perspex‐glass discs mounted in the slit between the Ultrotome base and the cryo‐chamber. In addition, modified constructions are presented of the grid‐carrier, the press‐assembly as well as of the container for freeze‐drying and warming up of the frozen sections.