Cytochemical variation of mast cells in the skin of the rat

Histochemical heterogeneity of mast cells in rat dermis

The dermal mast cells of Wistar rats were studied following fixation in either 10% phosphate buffered formalin or Carnoy's solution and staining with either toluidine blue or alcian blue:safranin O. Granules of mast cells appeared heterogeneous following fixation with formalin and staining with alcian blue:safranin O, but not when stained with toluidine blue. The number of mast cells observed in skin fixed in Carnoy's solution was greater than the number observed in equivalent samples of skin fixed in formalin (p < 0.01) when both samples were stained with toluidine blue. In formalin fixed skin stained with alcian blue:safranin O, there were three populations of mast cells designated as "blue," "red" or "mixed." "Blue" mast cells, containing only alcian blue stained granules, "red" mast cells, containing only safranin O stained granules, and "mixed" mast cells, containing both alcian blue and safranin O stained granules accounted for 77.6 +/- 3.0, 6.6 +/- 2.5 and 15.8 +/- 2.5% of the total mast cell population, respectively. In skin specimens fixed in Carnoy's solution and stained with alcian blue:safranin O the mast cells contained only blue granules (alcian blue positive). The number of mast cells observed in Carnoy's fixed skin sections was less than the number seen in formalin fixed skin sections when both were stained with alcian blue/safranin O. This indicates that there is a group of mast cells which do not stain with safranin O after fixation with Carnoy's solution.

Differential effects of the complement peptides, C5a and C5a des Arg on human basophil and lung mast cell histamine release

The ability of purified anaphylatoxins to induce human lung mast cell mediator release was investigated. In eight anti-IgE responsive (histamine release = 22 +/- 5%, mean +/- SEM) mast cell preparations of 1-96% purity, C5a and C5a des Arg (0.55 pg/ml to 55 micrograms/ml), failed to elicit or potentiate histamine release; lung fragments were similarly unresponsive. The related peptide C3a was also inactive. All anaphylatoxins failed to induce mast cell leukotriene C4 (LTC4) and prostaglandin D2 (PGD2) release. LTC4 release was also negligible from basophils where C5a was a potent histamine release stimulus. Supernatants from C5a-challenged mast cells remained fully active on basophils, excluding carboxypeptidase inactivation of C5a as an explanation for the lung mast cell results. In contrast to lung, skin mast cells were C5a-responsive (histamine release = 8 +/- 1%, at 55 micrograms/ml, n = 2). We conclude that C5a, though devoid of activity on the human lung mast cell, is a human basophil and skin mast cell secretagogue. These findings demonstrate significant organ-specific heterogeneity in mast cell responsiveness.

Effector cell heterogeneity in immediate hypersensitivity reactions

Histologic heterogeneity in the basophil and mast cell populations has been apparent for many years. The advent of tissue culture and cell separation procedures has now made it possible to explore distinct populations of basophils and mast cells, as should be evident from this review. In fact, the logical extension of such technology is the requirement that cell preparations used in exploring basophil and mast cell function be carefully defined to permit comparison of data from one laboratory to another. While this is a practical application of the knowledge of the characteristics of heterogeneity, the implications for future developments in the understanding of basophil and mast cell function are more theoretical. While both basophils and mast cells respond to degranulating stimuli and antiallergic compounds in a similar fashion, as a rule, this review has noted several exceptions including the failure of disodium cromoglycate to prevent rat mucosal mast cell degranulation induced by immunologic stimuli. Such observations suggest that the ability of given drugs to inhibit allergic responses in one target organ and not in another may be due in part to differing mast cell responses. This hypothesis can be extended to variation in response among infants, children, and adults to such drugs as antihistamines. Furthermore, the variety of symptoms seen in individuals may be a reflection of differing responses of those individuals' mast cells from organ to organ. For instance, one subject with ragweed sensitivity might express this sensitivity as asthma, and a second subject with ragweed sensitivity might express this sensitivity as rhinitis. This would depend upon the ability of their pulmonary and upper airway mast cells to bind ragweed-specific IgE, degranulate to IgE-mediated stimuli, or to be regulated by intrinsic control mechanisms. Of a yet more speculative nature is the attempt to discern the basis for basophil, and particularly mast cell, heterogeneity. The function of the mast cell is unknown, but theories include the rejection of parasites; regulation and repair of connective tissue; regulation of the microvasculature; regulation of gastric acid secretion; limitation of delayed hypersensitivity reactions; and detoxification of surrounding tissues. Any or all of these theories may be correct, however, such a diversity of possible biologic roles for the mast cell suggests that mast cell subpopulations may have highly specialized functions reflected in stimuli that lead to their proliferation, their response to degranulating stimuli, and their mediator content.(ABSTRACT TRUNCATED AT 400 WORDS)

A dual staining method for neutral complex carbohydrates using alkaline phosphatase-labeled concanavalin A and periodic acid-Schiff

A method has been developed for the dual staining of neutral complex carbohydrates in light microscopy. It combines an alkaline phosphatase-labeled concanavalin A-5-bromo-3-indolyl phosphate, p-toluidine salt (Con A-ALP-BIPT) method with periodic acid-Schiff (PAS) sequence. With the present dual staining method, it is possible to color alpha-D-glucosyl and alpha-D-mannosyl residues blue and 1,2-glycol groups of neutral complex carbohydrates magenta. The validity of this method has been confirmed with appropriate histochemical controls and enzyme digestions on test tissues.

Ultrastructural localization of glycogen in the granulocytes of normal rabbit bone marrow

The glycogen of rabbit granulocytes has been studied in glutaraldehyde and osmium tetroxide fixed bone marrow by the periodic acid-thiocarbohydrazide-silver proteinate procedure (PA-TCH-SP). The PA-TCH-SP procedure involved the staining of intracytoplasmic glycogen more densely than the routine lead citrate staining. The PA-TCH-SP procedure demonstrated the intracytoplasmic glycogen in all three kinds of granulocytes. Though a sequence of intensity was observed in each stage of cell maturation, intracytoplasmic glycogen increased generally in accordance with cell maturation in the granulocytes. Functional significance of the glycogen in the granulocytes was discussed in relation to its staining. A very weak reaction in the granules of the granulocytes was described in relation to their contents.

Concanavalin A-peroxidase-diaminobenzidine-periodic acid-m-aminophenol-fast black salt K: a method for the dual staining of neutral complex carbohydrates

A method has been developed for the dual staining of neutral complex carbohydrates in light microscopy. It combines a concanavalin A-peroxidase-diaminobenzidine (Con A-PO-DAB) method with a period acid-m-aminophenol-Fast Black salt K (PA-AP-FBK) sequence. With the combined method it is possible to stain alpha-D-glycosyl and alpha-D-mannosyl residues brown and 1,2-glycol groups of neutral complex carbohydrates blackish purple. The validity of the method has been confirmed with appropriate histochemical controls and enzyme digestions on test tissues.