Preparation of unfixed undemineralized bone sections: the Bright bone cryostat.

A bone cryostat is described with which cold sections of unfixed, undemineralized calcified tissue can be prepared. The bone cryostat is suitable for the preparation of the sections required for the histochemical and immunofluorescent study of bone, for electron microprobe analysis, and for bone and joint autoradiography with soluble compounds.

Neural crest origin of the endocrine polypeptide (APUD) cells of the gastrointestinal tract and pancreas.

A method of labelling known to be appropriate for the demonstration of endocrine polypeptide (APUD) cells was found to label the cells of the neural crest in the chick embryo after as little as 72 hours' development. The method depends on the production, from an exogenous precursor, of an amine which is stored in specific granules and which is convertible by treatment with hot formaldehyde vapour into a fluorescent derivative. The whole technique is described as APUD-FIF.

Immunofluorescent localization of secretin in the canine duodenum.

The endocrine polypeptide (APUD) cells responsible for the production and storage of secretin have been demonstrated, in canine duodenum, by the application of an indirect immunofluorescence technique, using anti-pure porcine secretin, to carbodiimide-fixed cryostat sections. The cells are identified, by the use of parallel cytochemical and ultrastructural preparations, as the small granular S cells. These are essentially restricted to the transitional zone of the duodenal mucosa, with whose lumen their apical projections probably always make contact.

The inducible alkaline phosphatase of rat heart. Some properties of the enzyme and factors influencing its activity.

Subcutaneous injection of isoprenaline into rats produces a rapid rise in alkaline phosphatase activity which is largely confined to the right atrium of the heart. The phosphatase activity of extracts of atrial tissue from treated animals is on average four times that of controls. The rise in activity is largely suppressed by previously treating the animals with cycloheximide or actinomycin D.

The G cells in pernicious anaemia.

An indirect immunofluorescence technique, using the globulin fraction of rabbit antihuman gastrin serum, was applied to formalin-fixed material obtained by suction biopsy from the fundic mucosa of nine cases of pernicious anaemia. Cytochemical tests for endocrine polypeptide cells of the APUD series, in which the G cell is included, were carried out in parallel with immunofluorescence and with ultrastructural observations.G cells were present, in large numbers, in five of the nine cases studied.

Immunofluorescent localization of enteroglucagon cells in the gastrointestinal tract of the dog.

Localization of the endocrine polypeptide cells responsible for ;glucagon-like immunoreactivity' in the gastrointestinal tract of the dog has been achieved with an immunofluorescent technique using antibodies raised against porcine pancreatic glucagon. The cells, for which we prefer the term ;enteroglucagon', could only be demonstrated by this technique in tissues fixed in carbodiimide. The enteroglucagon cells possess cytological, cytochemical, and ultrastructural characteristics in common with those of the pancreatic alpha(2) cell and they are equivalent in the stomach to the A cell and in the intestine to the L cell of the Wiesbaden terminology.