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Results for “mast cells”

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At least 19 recordsLinked to original sources
PubMed1977

Microspectrophotometric detection of heparin in young and adult rat mast cells, human mast cells and human basophilic granulocytes stained metachromatically with toluidine blue O.

A qualitative microspectrophotometric detection method for heparin in situ has been developed, using data obtained previously with a model system of polyacrylamide films containing pure glycosaminoglycans (Tas & Roozemond 1973, and Tas 1975). This technique, based on the unique metachromatic properties of heparin with Toluidine Blue O in glycerol, has been worked out with rat peritoneal and mesenteric mast cells. After equilibration of the stained, air-dried cells in glycerol (for some days), the specific peak of the heparin-Toluidine blue O complex (as found in the model experiments at about 515 nm) could be recorded. It was found that the method can be used to detect unequivocally the presence of heparin in cells, even if they also contain up to 75 mole percent of other, lower sulphated-glycosaminoglycan. Otherwise the method might yield some information about the degree of sulphation of the heparin concerned. With this technique the presence of heparin has been proved in young and adult rat mast cells and for the first time now directly in normal human mast cells and normal human basophilic granulocytes.

Aging↗
PubMed1976

Observations of the pathology of clubbed fingers with special reference to mast cells.

Mast cell counts were made, in tissue samples of normal and clubbed fingers obtained at autopsy, to investigate the possibility that mast cells act as an intermediary in the development of finger clubbing. Quantitative measurements of the composition of the tissues of the normal and clubbed nail bed were also made. The only significant difference in mast cell numbers in clubbed fingers was a decrease in mast cells in the tissues just superficial to the nail. The appearance of the mast cells was normal. The porportion of blood vessels and other tissues was not significantly different from normal.

Cell Count↗
PubMed1975

Intracellular distribution of amines taken up by rat mast cells.

Mast cells isolated from rat peritoneal and pleural cavities were incubated in vitro with radioactively-labelled histamine (Hi), 5-hydroxytryptamine (5-HT), dopamine (DA), noradrenaline (NA), tyramine (TA), phenylethylamine (PhEA), trptamine (TrpA), ephedrine (Eph) or amphetamine (Amph). All these amines were taken up by the mast cells. The dose-response curves for the compound 48/80-induced release of endogenous Hi and for the various amines taken up by the cells were compared. The release curves for Hi, 5-HT, DA, NA and TA were found to be similar to that for endogenous Hi, while those for PhEA, TrpA, Eph and Amph were different from that for endogenous Hi. The uptake of Hi, 5-HT, DA, PhEA, TrpA and Eph into granules in mast cells was studied. Membrane-bound granules were obtained by sonication of mast cells incubated with the respective amine, followed by differential contrifugation. The amine content of these granules was then measured. Hi, 5-HT and DA were found to be mainly localized to the granules, while a smaller proportion of the PhEA, TrpA and Eph was found there, the rest being located extragranularly. The present results suggest that, when taken up by rat mast cells, even amines which are not endogenous to the cells are stored in the same way as the endogenous amines Hi and 5-HT.

Amines↗
PubMed2026

Mast Cells Selectively Deliver Extracellular Vesicle-Encapsulated mRNA to Colorectal Cancer Cells.

Mast cells (MCs), a type of granulocytic immune cell, exert contrasting effects on tumorigenesis. The anti- or pro-tumorigenic activity of MCs depends on the cancer type, tumor microenvironment, and MC localization within the tumor. Consequently, their role remains controversial and poorly understood across multiple cancer types, including colorectal cancer (CRC). Most proposed mechanisms underlying MC activity in CRC have focused on MC secretion of biological factors. In this study, we demonstrated that MCs transfer extracellular vesicles containing mRNAs and proteins to CRC cells. This process occurs through a tightly regulated mechanism that requires direct cell-cell contact, calcium signaling, and integrin-mediated interactions. Such requirements resemble aspects of immunological synapses observed between lymphocytes and cancer cells. The novel mode of intercellular communication between MCs and cancer cells described here may help refine our understanding of MC functions in cancer biology.

Mast Cells↗
PubMed1976

Development of rat mast cells in vitro. I. Differentiation of mast cells from thymus cells.

Mast cells were differentiated by long-term culture of rat thymus cells on rat embryonic fibroblasts monolayers. Mature mast cells obtained in the culture were morphologically similar to normal peritoneal and thoracic mast cells and possessed specific receptors for IgE on their surface. In culture, blast cells appeared on the monolayer several days after seeding of thymus cells. These cells developed into young mast cells in the monolayer and became free in the culture medium with maturation. Receptors for IgE were detected on the surface of mastoblasts which contained a small amount of metachromatic granules. Evidence was obtained which suggested that the number and/or affinity of the receptors for IgE increases with maturation of mast cells. It was found that some mast cells differentiated from monolayers of embryo cells without seeding thymus cells. The present experiments, however, clearly showed that mast cells can be differentiated from thymus cell culture without monolayer. It appears that both thymus and embryo tissues contain precursors of mast cells.

Animals↗
PubMed1979

Ultrastructure of pulmonary mast cells in patients with fibrotic lung disorders.

The topographic distribution, population density, and ultrastructural features of metachromatic cells (mast cells and basophilic leukocytes) were studied in lung biopsies from five control patients and 17 patients with fibrotic lung disorders. The great majority of metachromatic cells were mast cells. The average number of metachromatic cells per square millimeter of tissue section was much larger in patients with fibrotic lung disorders (45.8 +/- 6.5) than in control patients (2.6 +/- 1.6). In control patients, mast cells were most frequently seen in subpleural and perivascular connective tissue. In contrast, the vast majority of mast cells in patients with fibrotic lung disorders was present in thickened, fibrous alveolar septa; mast cells also were found within the alveolar epithelial layer and alveolar lumina. The quantitative distribution of different types of mast cell granules differed in the two groups of patients: granules composed of scrolls were more frequent in control patients, and granules of the combined type (containing mixtures of different components within the same granule) were more frequent in patients with fibrotic lung disorders. Mast cells in the latter patients appeared to migrate through defects in the basement membrane into the epithelial layer and alveolar lumina; mast cells in these areas often showed reduced numbers of granules and disorganized granule content. These changes suggest that pulmonary parenchymal mast cells in fibrotic lung disorders undergo a chronic process of partial degranulation which differs from that found in anaphylaxis; this chronic release of mast cell products may contribute to the continuing alveolar injury and the ventilation-perfusion inequalities observed in the fibrotic lung disorders.

Adult↗
PubMed1979

Cytology of canine cutaneous round cell tumors. Mast cell tumor, histiocytoma, lymphosarcoma and transmissible venereal tumor.

Sixty-four canine cutaneous round cell tumors were divided into 25 mast cell tumors, 15 histiocytomas, nine cutaneous lymphosarcomas and 15 transmissible venereal tumors. The final diagnosis was made from cytologic, clinical and histologic findings. Cytologic features were significantly distinctive in mast cell tumor, transmissible venereal tumor, and most cases of histiocytoma and lymphosarcoma to allow a diagnostic opinion. This opinion was supported by subsequent histologic examination. In some instances cytology was considered essential in rendering a diagnostic opinion even though histology was available.

Animals↗
PubMed1977

Uptake of 5-hydroxytryptamine by mast cells in vivo: a cytofluorometric study of mast cells and individual mast cell granules.

Uptake, distribution and turnover of 5-Hydroxytryptamine (5-HT) was studied by cytofluorometric analysis of whole mast cells and individual granules. Injection of 5-HT as well as 5-Hydroxytryptophan (5-HTP) intraperitoneally or subcutaneously resulted in a parallel uptake of 5-HT in cells and granules. Intraperitoneal injections of 5-HT in such small quantities that may be available under physiological conditions resulted in an increase in fluorescence intensity of the mast cells, indicating a very efficient uptake mechanism for 5-HT in vivo. Much larger doses of 5-HTP were required to obtain a corresponding uptake of 5-HT in the mast cells. The 5-HT was rather rapidly taken up in the granules and eliminated very slowly, at the same rate both from granules and mast cells. The low elimination rate confirms our previous findings that the turnover of 5-HT is much lower in mast cells than in other amine containing cell systems. The combination of an extremely efficient, rapid uptake of 5-HT with a slow elimination suggests a specific function for mast cells in the regulation of free amine concentrations in tissues.

5-Hydroxytryptophan↗
PubMed1977

Development of mast cells in vitro. II. Biologic function of cultured mast cells.

Mast cells were obtained by long term culture of rat thymus cells on rat embryonic fibroblast monolayers. Pure mast cell preparations obtained culture were incubated with 125I-labeled rat E myeloma protein to study receptors for IgE on their surface. When the cells were obtained after 35 to 45 days culture, the average number of receptors per mast cell was 100,000 to 400,000. An equilibrium constant of the binding reaction between their receptor and rat IgE was in the order of 108 M-1. The histamine content of the cultured mast cells was 0.2 to 5 mug/106 cells. The measurement of histamine content in mast cells recovered after different periods of culture suggested that the histamine content increased with maturation. Even after 45 to 50 days culture, the histamine content of cultured mast cells was significantly lower than that in rat peritoneal mast cells. The cultured mast cells were passively sensitized in vitro with rat IgE antibody against Nippostrongylus brasiliensis. The sensitized cells released histamine upon incubation with the antigen. It was also found that cultured mast cells released histamine upon exposure to compound 48/80. These results indicated that cultured mast cells have physiologic functions similar to those of normal rat mast cells, but they have not reached full maturation.

Animals↗
PubMed1976

3H-Thymidine labeled mast cells in mice treated with 20-methylcholanthrene: proliferation of precursor cells, their transformation into mast cells and migration of the latter.

In an attempt to clarify the kinetics of increase of mast cells, autoradiographic studies were performed on the mice which received a painting of 20-methylcholanthrene on the skin. In the first experiment, mice received 20-methylcholanthrene painting on their back for two, four and eight weeks. A fourty-eight hours' cumulative labeling with 3H-thymidine was performed directly before sacrifice. No labeled mast cells were found in the painted skin, despite a marked increase of mast cells in number. In the second experiment, mice received 20-methylcholanthrene painting for thirty-one days. A twenty-four hours' cumulative labeling was performed three, five, seven, fourteen, twenty-one and thirty-one days before sacrifice. A high labeling index of mast cells, up to 61.29%, was obtained in each group. When the time lapse between the time of cumulative labeling and the sacrifice is long, the labeling index is higher in the subcutaneous tissue, and when the time lapse is short, the labeling index is higher in the subepidermal tissue. From these results it was concluded that; 1) An increase of mast cells is due predominantly to the proliferation of precursor cells and their transformation into mast cells. 2) The proliferation of precursor cells occurs mainly in the subepidermal layer of the skin. 3) After the transformation, mast cells may migrate into the deeper layer of the skin.

Administration, Topical↗
PubMed1977

Separation of lymphocytes and mast cells from the Furth transplantable mast cell tumor in an isokinetic gradient of Ficoll in tissue culture medium.

Cell suspensions of the transplantable Furth murine mast cell tumor were separated both by velocity sedimentation in an isokinetic gradient and by isopyknic sedimentation. Prior to separation, the suspension of tumor cells contained 60.3+/-13.1% (S.D.) malignant mast cells, 9.8+/-10.4% lymphocytes, 4.3+/-2.1% granulocytes, 1.7+/-1.9% macrophages, 0.6+/-0.4% unidentified cells, and 22.8+/-8.5% red blood cells. After either isokinetic or isopyknic sedimentation, more than 97% of the nucleated cells in the purest modal fraction were malignant mast cells. Velocity sedimentation in the isokinetic gradient offered several advantages over isopyknic separation of this tumor; namely, in isokinetic sedimentation, the cells are exposed to a lower centrifugal force for a shorter period of time; a much larger proportion of mast cells were in the highly purified zone of the gradient following velocity sedimentation; and lymphocytes were more highly purified (88.9+/-10.1% of the nucleated cells) following velocity sedimentation. Granulocytes and macrophages were purified more than 8-fold over the nucleated cells in the starting sample suspension. The purified cells from this tumor offer the opportunity to study the interactions between highly purified, easily identified, malignant cells and cells that may participate in the defense of the host against cancer.

Cell Separation↗
PubMed1978

Histamine content and mast cells in human gastric and duodenal mucosa.

A high histamine content was found in all areas of human gastric and duodenal mucosa. In single subjects there was no general preference of histamine being located predominantly in fundus and corpus. In biopsy specimens of human corpus mucosa many histamine-containing O-PD reactive cells could be identified. In the sections treated previously with O-PD also many toluidine blue staining cells (mast cells) could be visualized. As shown by a transcription technique their place and number was the same as those of O-PD reacting cells. It is concluded that histamine in human corpus mucosa is localized exclusively in mast cells which seem to participate in acid secretion and in duodenal ulcer disease in man.

Duodenum↗