Immunofluorescent localization of the gastrin-secreting G cells in the pyloric antrum of the pig

Summary An indirect immunofluorescence technique, using anti-human gastrin serum, was applied to formalin-fixed, paraffin-embedded material from antral tissues of porcine stomach. After photographing the result, post-fixation in formalin was followed by the Grimelius silver technique. The argyrophil G cells, situated predominantly in the middle zone of the gastric glands, all showed positive gastrin immunofluorescence. Some weakly fluorescent cells failed to stain by the silver technique, suggesting that the latter is less sensitive than immunofluorescence in that it depends on the presence of the granular storage product.     

Aldehyde-fuchsin staining of antral endocrine cells.

Correlative studies have been made to identify the endocrine cells stained by Aldehyde-Fuchsin (AF) in the cat and human antral mucosa. D-cells weakly stained by AF after oxidation: this staining might be related to the disulphide group present in the molecule of Somatostatin (the hypothalamic hormone recently localized in D-cells). The gastrin-producing G-cells were on the contrary strongly stained (without oxidation) in tissues fixed in Helly-fluid. Histochemical investigations on the mechanism of such staining lead to the conclusion that it might be related to affinity of the stain for hidden acidic groups.     

Fast and slow myosins as specific markers of muscle: an immunocytochemical study

Slow and fast myosins are specific markers of skeletal muscle. The specificity of anti-fast and anti-slow myosin antisera been verified on frozen and paraffin embedded tissues. The optimal fixative useful for routine histopathological purposes has been investigated. It is suggested that these two antisera can be used in the diagnosis of rhabdomyoblastic tumours substituting for or complementary to myoglobin, a well known marker of striated muscle.     

Nonspecific staining of mast cells by avidin-biotin-peroxidase complexes (ABC)

A nonspecific staining of mast cells by avidin-biotinylated peroxidase complexes (ABC) has been observed and related to an ionic binding of the basic residues of avidin (isoelectric point at pH 10) and peroxidase to the sulphate groups of heparin. This affects the correct interpretation of the results of the immuno-peroxidase ABC procedure, especially in mast cells-rich areas such as the lymphoid tissues. The spurious staining can be prevented by using the ABC solution at pH 9.4 (instead of pH 7.6 as usually recommended): this high pH does not affect the previous binding of primary antibodies nor the affinity of avidin to biotin. The modified ABC procedure provides a clear background and a sharp specific staining and can be recommended for routine use.     

A combined histological, immunocytochemical and biochemical approach in the evaluation of estrogen receptors in breast carcinomas

Correlation of structural and functional data might lead to better identification of hormone-dependent tumors. Sixty breast cancer specimens, sent to the biochemistry laboratory for estrogen receptor (ER) analysis, were studied here by a combined morpho-functional approach. Histological examination of needle biopsies on frozen tissue blocks showed that 12 cases (10%) were free of tumor cells; these cases mostly proved ER negative. On the other 48 cases, an immunocytochemical reaction was performed on the biopsy sections with a monoclonal antibody directed against p 29, an estrogen receptor related antigen. The staining values for p 29 and the biochemical ER findings were significantly correlated. A combined histological, immunocytochemical study seems to offer advantages in the selection of patients for hormonal therapy.