title: A rapid method of cryofixation of tissues in situ for ultracryomicrotomy.
abstract: A device is described for the rapid freezing of tissue in situ by a punch biopsy approach using a specially designed cryogun with a highly thermal conductive specimen holder. The cryogun consists of a sampling device using a double, spring-loaded gun mechanism and a system of cryochambers. Ultrathin freeze-dried sections cut from samples obtained with this cryogun are relatively free of artifacts and have few ice crystals. Organelles are seen by natural contrast when cryosections of approximately 1000 A are observed with a transmission electron microscope or in the transmission mode of a scanning electron microscope. The construction of the cryogun is described along with a method of obtaining improved, ultrafast cryofixation of tissue specimens. The reliability of obtaining x-ray microanalysis measurements of diffusible ions where movement within cell compartments has been retained is discussed.
mesh_terms: D001485:Basement Membrane / Q000648:ultrastructure; D001706:Biopsy; D005615:Freezing; D006651:Histocytochemistry; D006801:Humans; D007672:Kidney Cortex / Q000166:cytology* / Q000648:ultrastructure; D007687:Kidney Tubules, Proximal / Q000166:cytology* / Q000648:ultrastructure; D008871:Microvilli / Q000648:ultrastructure