Mast cell maturation in young rats: a histofluorescence and cytochemical study.

Since they are not submitted to experimental alterations new-born rats are useful for the investigation of mast cell maturation and were therefore analysed in the present study. In the mesentery of new-born rats immature mast cells were present within and close to fat sheaths containing blood vessels. On day 15, mast cells were also found in mesentery windows and generally in a more advanced stage of maturation.

Immunocytochemical identification of immature rat peritoneal mast cells using a monoclonal antibody specific for rat mast cells.

The lack of immunological or morphological markers makes identification of immature mast cells difficult. In the present study we have used a rat mast cell specific monoclonal antibody (mAb AA4) to immunolabel mast cells during repopulation of the peritoneal cavity. Peritoneal cells were collected six days after injection of distilled water and examined by light and electron microscopy.

Reduction of epidermal cell proliferation in skin lesions in lepromatous leprosy is greater than in indeterminate and tuberculoid leprosy lesions.

We have compared epidermal cell proliferation in skin biopsies from areas with lesions to contralateral areas without lesions in patients with indeterminate, tuberculoid and lepromatous leprosy. Cell proliferation was determined as the percentage of labeled cells in the basal and suprabasal epidermal layers, using autoradiographic preparations of skin biopsies taken 1 hr after a 3H-thymidine intradermal injection. We have found a significant reduction in epidermal cell proliferation in areas with lesions in the three groups of patients.

Quantitative immunocytochemical study of secretory protein expression in parotid glands of rats chronically treated with isoproterenol.

Chronic treatment of mice and rats with isoproterenol (IPR) causes marked hypertrophy and hyperplasia of the salivary glands, and alters the expression of several secretory proteins. We used quantitative postembedding immunogold labeling to study the cellular responses in the rat parotid gland during daily (up to 10 days) injections of IPR and during recovery (up to 14 days) after cessation of IPR treatment. Labeling densities of acinar cell secretory granules with antibodies to amylase and protein SMG-B1 (cross-reactive with the rat homologue of Parotid Secretory Protein, PSP) fell to 10% of control levels after 8-10 IPR injections, then increased during recovery, paralleling previous biochemical determinations of changes in protein and mRNA levels.

Ultrastructural similarity between bat and human mast cell secretory granules.

Mast cells in the tongue of the bat (Artibeus lituratus) show a well-developed Golgi area and abundant mitochondria in the granule-free perinuclear cytoplasm. Rough endoplasmic reticulum profiles, free ribosomes, mitochondria, bundles of filaments and a great number of secretory granules are found throughout the remaining cytoplasm. The granules, of various shapes and sizes, are simple containing an electron-dense, homogeneous matrix, coarse particles or cylindrical scrolls, or combinations (cylindrical scrolls with either electron-dense, homogeneous matrix or coarse particle contents).

Cytochemical demonstration of acid phosphatase, trimetaphosphatase and basic protein in rat peritoneal mast cells during 48/80 induced exocytosis.

Acid phosphatase (AcP-A), trimetaphosphatase (TmP-A) activities and basic protein reaction were cytochemically studied in rat peritoneal mast cells 15 minutes after stimulation by compound 48/80. The AcPase reaction was positive in slightly altered granules, but negative in those more intensely altered, and also in unaltered granules. The TmP-A reaction was negative in altered granules and positive in a few unaltered granules.

Reduction in rat mesentery mast cell staining after degranulation by protamine. A competitive antagonism.

Degranulation of rat mesentery mast cells by increasing concentrations of protamine causes a parallel decrease in the numbers of mast cells stained with toluidine blue or with berberine sulfate. No decrease in mast cell numbers occurs when degranulation is inhibited. Since protamine does not enter into non stimulated mast cells, these results suggest that this reduction in mast cell numbers is caused by the binding of protamine to the anionic sites of heparin of exocytosed granules thereby preventing their staining.

Cytochemical evidence of lack of basic protein in mucosal mast cells of the small intestine in the rat.

The ammoniacal silver method, which identifies basic proteins, gives a positive reaction in cytoplasmic granules of rat peritoneal mast cells. However, in cytoplasmic granules of mucosal mast cells in the small intestine of the rat, this reaction is negative.

Non cytotoxic guinea-pig mesenteric mast cell stimulation by protamine.

Protamine stimulates guinea-mesenteric mast cells in a concentration-dependent manner, both histamine release and mast cell degranulation being correlated. Mast cell stimulation is blocked by 2,4-DNP (0.03 mM), low (0 degrees C) and high (45 degrees C) temperature.

Maturation of adult rat peritoneal and mesenteric mast cells. A morphological and histofluorescence study.

Repopulation and maturation of rat mesenteric and peritoneal mast cells were studied after mast cell depletion by intraperitoneal injection of distilled water. Immature mast cells were first identified in the mesentery and peritoneal fluid 5 and 6 days, respectively, after water injection. The most immature mast cells that could be identified contained a few orthochromatic granules.

Ultrastructural and cytochemical studies of acid phosphatase and trimetaphosphatase in rat peritoneal mast cells developing in vivo.

The ultrastructural and cytochemical features of peritoneal mast cells of the rat were studied. Immature mast cells show specific cytoplasmic granules of different sizes, the smaller ones localized in the Golgi region. The rough endoplasmic reticulum and Golgi apparatus are well developed, and mitochondria are numerous.

Ectopic bone marrow development in experimental busulfan-induced hypoplastic anemia in mice.

The intramuscular implantation of devitalized bone matrix in 42 mice with busulfan-induced bone marrow failure and in 42 control mice led to the sequential formation of ectopic cartilage, bone and bone marrow. The morphological volumetric estimation of these components in the hypoplastic mice showed a significant increase in cartilage and a decrease in hematopoietic bone marrow as compared with control mice. The cellularity in the ectopic hematopoietic bone marrow was similar to that of sternal bone marrow.

Toad (Bufo paracnemius) mast cell degranulation by compound 48/80 and by chlorpromazine: a non-lytic process.

Toad mast cells are degranulated by compound 48/80 and by chlorpromazine. The former was effective at rather high (100 micrograms/ml) and the latter at low (0.1 mM) concentrations.

Ultrastructure of toad (Bufo paracnemius) mast cells. Their alteration by compound 48/80.

The fine structure of toad mast cells and their alteration by compound 48/80 is described. The specific cytoplasmic granules, which stain metachromatically with toluidine blue, seem to be of one type only, notwithstanding wide differences in their appearance. They are composed of an electron-dense, peripheral, lamellar component, and a matrix showing a particulate material embedded in a homogenous ground substance.

Dual effect of verapamil on rat peritoneal mast cells: inhibition or induction of histamine release.

1. Verapamil (1.0 microM) inhibits histamine release from rat peritoneal mast cells induced by both compound 48/80 (Burroughs Wellcome), an external calcium-independent stimulant, and by protamine, an external calcium-dependent stimulant.