Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.4 (trypsin)
 42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Primitive clonogenic progenitor cells in human bone marrow bind to preformed marrow-derived stromal layers in vitro and generate colonies of blast cells. The binding interaction does not require calcium or magnesium ions and occurs equally well in serum-free and serum-supplemented culture medium. It does not appear to involve known cell adhesion molecules (CAMs) for which monoclonal antibodies are available (integrins, N-CAM, LFA-1, and ICAM-1), and we were unable to demonstrate a role for the progenitor cell antigen CD34 in progenitor cell adhesion to cultured stroma. The CAM expressed by the blast colony-forming cells may exist in transmembrane or phosphatidylinositol (PI)-linked forms because it is only partially degraded by exposure to trypsin or to PI-specific phospholipase C. However, binding of these cells to stroma is not prevented in the presence of monoclonal antibodies reacting with known PI-linked structures (Thy-1, CD14, and CD16). It is either masked by neuraminidase-sensitive residues or is no longer expressed as cells mature, respectively, along the granulocytic or erythroid lineages. The properties of the hemopoietic progenitor CAM are discussed with reference to the properties of other CAMs and of hemopoietic progenitor cell markers.
 ...
PMID:Hemopoietic progenitor cell binding to the stromal microenvironment in vitro. 237 49

Mast cells may be cultured from human peripheral blood in the presence of recombinant human stem cell factor (rhSCF). The characteristics of the cells in peripheral blood that give rise to mast cells are unknown. Because mast cell precursors in human marrow are CD34+, human peripheral blood mononuclear cells from patients with mastocytosis and normal controls were sorted on the basis of CD34 expression and the positive and negative cell populations were cultured in rhSCF, recombinant human interleukin-3 (rhIL-3), or both for 6 weeks. Cell cultures were examined every 2 weeks for total and mast cell number and cell differential using Wright Giemsa and acid toluidine blue stains and antibodies to mast cell tryptase and chymase, cell-associated histamine, and expression of CD34, c-kit, Fc epsilon RI, and Fc gamma RII using flow cytometric analysis. The ultrastructural anatomy of mast cells was examined by electron microscopy. Peripheral blood CD34+ cells cultured in rhSCF with or without rhIL-3 gave rise to cell cultures consisting of greater than 80% mast cells by 6 weeks. CD34+ cells cultured in rhIL-3 alone did not give rise to mast cells, whereas rhIL-3 plus rhSCF increased the final mast cell number eightfold when compared with cells cultured in rhSCF alone. Mast cells increased concomitantly with a decrease in large undifferentiated mononuclear cells. CD34- cells did not give rise to mast cells. Histamine content per cell at 6 weeks was approximately 5 pg. Electron microscopy of 4-week cultures showed immature mast cells containing predominantly tryptase-positive granules that were either homogeneous or contained lattice structures, partial scroll patterns, or central dense cores and mixtures of vesicles, fine granular material, and particles. The CD34+ population at day 0 expressed Kit (65%) and Fc gamma RII (95%), but not Fc epsilon RI, by fluorescence-activated cell sorter analysis. At 6 weeks, CD34+-derived mast cells exhibited Fc epsilon RI in addition to Kit and Fc gamma RII, and were negative for CD34 antigen. Patients with mastocytosis showed a higher number of mast cells per CD34+ cell cultured compared with normal controls. Thus, the mast cell precursor in human peripheral blood is CD34+/Fc epsilon RI- and gives rise to mast cells in the presence of rhSCF with or without rhIL-3, and the number of mast cells arising per CD34+ cell in culture is greater when the CD34+ cells are obtained from patients with mastocytosis compared with normal subjects.
 ...
PMID:Mast cells cultured from the peripheral blood of normal donors and patients with mastocytosis originate from a CD34+/Fc epsilon RI- cell population. 752 30

Recent studies of mesenchymal cells of the dermis using antibodies to factor XIIIa (FXIIIa) and CD34 have demonstrated immunophenotypic heterogeneity amongst the normal resident spindle/dendritic cells of the dermis. These immunohistochemical markers also have been reported to be useful in the distinction between two dermal mesenchymal tumors of uncertain histogenetic origin - the dermatofibroma (DF) and dermatofibrosarcoma protuberans (DFSP). DFs are FXIIIa positive, CD34 negative while DFSPs are FXIIIa negative and CD34 positive. Expression of CD34 may also have histogenetic implications for these cutaneous neoplasms. In order to further study these tumors we studied 13 DFs and 12 DFSPs immunohistochemically using a microwave antigen retrieval technique in formalin fixed, paraffin embedded tissue with antibodies to FXIIIa, CD34, CD45, factor VIII related antigen (FVIII-RA), the Ki-67 antigen (MIB-1 antibody) and the lectin Ulex europaeus. Of the DFs, all 13 were FXIIIa positive; 12/13 were CD34 negative and 1 was strongly CD34 positive. All DFSPs were FXIIIa negative and CD34 positive. One DFSP also contained an area of fibrosarcoma which was negative for both markers. All tumors were negative with anti-FVIII-RA Ulex europaeus, and anti-CD45. MIB-1 staining demonstrated nuclear staining of the tumor cells in both DFs and DFSPs. Image analysis of MIB-1 stained sections revealed a significant difference in mean percent positive nuclear area between DFs (1.16% +/- 0.405) and DFSPs (2.265% +/- 0.963). In summary, FXIIIa reliably distinguished between DFs and DFSPs; however, CD34 immunoreactivity can be seen in DFs. No evidence for vascular or hematopoietic origin of these tumors was found using microwave antigen retrieval and anti-FVIII-RA, Ulex europaeus, or CD45 staining. With microwave enhancement trypsin was not necessary for FXIIIa staining; however, it did not significantly enhance detection of FVIII-RA, CD45, or Ulex antigens. DF and DFSP tumor cells are in the cell cycle as demonstrated by MIB-1 staining and there are significant differences in percent positive nuclear area between these neoplasms, being higher in DFSP compared to DF.
 ...
PMID:Dermatofibroma and dermatofibrosarcoma protuberans: an immunohistochemical study reveals distinctive antigenic profiles. 886 61

We describe a subcutaneous mucinosis developing in the right cheek of a 38-year-old man. Histologic examination revealed bipolar fibroblast-like cells embedded in a well demarcated mucinous stroma in the subcutis without a manifest reticulin network. In addition, bizarre, sometimes multinucleate, cells with intranuclear vacuoles were found at the periphery of the mucinous stroma. Immunohistologically, both the bipolar fibroblastic cells and bizarre-shaped cells were positive for vimentin, but were negative for smooth muscle A-actin, desmin, CD34, S100, trypsin, or chymotrypsin. However, the latter reacted to anti-factor XIIIa antibody, suggesting that they are derived from dermal dendritic cells. We think that this solitary subcutaneous mucinosis is a unique variant of cutaneous focal mucinosis, because neither a reticulin network nor reactivity to anti-smooth muscle A-actin antibody were demonstrable.
 ...
PMID:Solitary subcutaneous mucinosis surrounded by bizarre-shaped, factor XIIIa-positive cells with intranuclear vacuoles. 969 93

KleinJan et al. (Allergy 1996;51:614-20) reported that Carnoy's fixative reduced the number of chymase-positive mast cells in the nasal mucosa. Therefore, in the present study, we investigated whether Carnoy's fixative reduces the number of chymase-positive cells from cord-blood-derived human cultured mast cells when compared with other types of fixatives. Human mast cells were obtained by culturing cord-blood-derived CD34-positive cells in the presence of stem cell factor and interleukin-6. Staining procedures of the cells in fixation with Carnoy's fixative and with other fixatives gave no differences among the number of tryptase-positive cells, whereas fixation with Carnoy's fixative for 15 min gave a significant decrease in the number of chymase-positive cells compared with acetone for 10 min. The number of chymase-positive cells decreased in a time-dependent manner under fixation with Carnoy's fixative, indicating that Carnoy's fixative had a negative effect on the number of chymase-positive cells from cord-blood-derived human cultured mast cells.
 ...
PMID:Carnoy's fixative reduces the number of chymase-positive cells in immunocytochemical staining of cord-blood-derived human cultured mast cells. 982 79

A subset of patients with systemic mastocytosis (SM) develop acute myeloid leukaemia (AML). However, little is known about the biology of such leukaemias and their relationship to the mast cell (MC) lineage. We report on two female patients who suffered from SM and AML. According to FAB criteria, the leukaemias were classified as AML-M4 (patient 1) and AML-MO (patient 2). The coexistence of the two distinct neoplasms (AML and SM) was demonstrable by immunostaining of serial bone marrow (BM) sections with monoclonal antibodies (mAb). In particular, the MC infiltrates were found to react with mAb against MC-tryptase and MC growth factor receptor c-kit (CD117), but not with mAb to CD15 or CD34. In contrast, the AML blasts were immunoreactive for CD15 (patient 1) or CD34 (patient 2), but did not express tryptase. The c-kit point mutation Asp-->Val at codon 816, considered to play a role in the transformation of MC progenitors, was detected in patient 1 in a BM cell fraction containing 4% MC. However, no c-kit mutation was found in pure AML blasts (<1% MC). These findings argue against an evolution of the AML clone from neoplastic MC or MC-committed progenitors.
 ...
PMID:Systemic mastocytosis associated with acute myeloid leukaemia: report of two cases and detection of the c-kit mutation Asp-816 to Val. 985 25

Angiogenesis is in part related to mast cells. However, the biological significance of mast cells within lung carcinoma remains unclear. Immunohistochemistry was used to stain for tryptase, CD34 and vascular endothelial growth factor (VEGF) in 85 cases of stage I nonsmall cell lung carcinoma. VEGF was found in 33 of 53 adenocarcinomas and 14 of 32 squamous cell carcinomas. Cases of adenocarcinoma had significantly higher mast cell counts than those of squamous cell carcinoma. In adenocarcinoma, mast cell counts in VEGF-positive tumours were significantly higher than in VEGF-negative tumours, whereas in squamous cell carcinoma they were not. Good correlation was observed between intratumoural mast cell counts and microvessel counts. Double staining showed most intratumoural mast cells expressed VEGF. Importantly, only in lung adenocarcinoma, members in the high mast cell count group had significantly worse prognosis than those in the low mast cell count group. It is concluded that tumour-released vascular endothelial growth factors may be related to mast cell accumulation, intratumoural mast cells may produce vascular endothelial growth factor, and stromal mast cells correlate with angiogenesis and poor outcome in stage I lung adenocarcinoma.
 ...
PMID:Mast cells correlate with angiogenesis and poor outcome in stage I lung adenocarcinoma. 1088 28

To investigate the possible role of mast cells (MC) in the angiogenic process in cutaneous melanoma, we examined tissue samples from 35 adult patients with primary malignant melanoma and compared with 20 intradermal benign nevi. MC were identified by anti-tryptase, microvessels by anti-CD34, and vascular endothelial growth factor (VEGF) expression by standard immunohistochemical methods. Tryptase-positive MC expressing VEGF were identified by double immunostaining. The numbers of MC and microvessels around the tumor were determined by the point counting method. MC density was significantly greater in melanoma compared with benign nevi (197.6 +/- 19.4 v 95.7 +/- 5.0/mm2, P < .001). Vascular density was also significantly higher in melanoma than in benign lesions (3.6-fold, P < .001). Double immunostaining showed the presence of VEGF in the cytoplasm of tryptase-positive peritumoral MC. The percentage of this MC-subtype was significantly higher in melanoma than in nevus tissues (71.9 +/- 2.4% v 30.6 +/- 2.5%, P < .001). A strong significant correlation was shown between the number of VEGF+ MC and microvessel density (r = .811, P < .001). MC count and VEGF+ MC count, as well as microvessel density were significantly higher in aggressive (metastasizing) melanomas (P < .001). Our results suggest that peritumoral accumulation of MC and the subsequent release of potent angiogenic factor such as VEGF may thus represent a tumor-host interaction that may favor progression of this tumor.
 ...
PMID:Cutaneous malignant melanoma: correlation between neovascularization and peritumor accumulation of mast cells overexpressing vascular endothelial growth factor. 1098 56

We compared a potential to generate mast cells among various sources of CD34(+) peripheral blood (PB) cells in the presence of stem cell factor (SCF) with or without thrombopoietin (TPO), using a serum-deprived liquid culture system. From the time course of relative numbers of tryptase-positive and chymase-positive cells in the cultured cells grown by CD34(+) PB cells of nonasthmatic healthy individuals treated with G-CSF, TPO appears to potentiate the SCF-dependent growth of mast cells without influencing the differentiation into mast cell lineage. CD34(+) PB cells from asthmatic patients in a stable condition generated significantly more mast cells under stimulation with SCF alone or SCF+TPO at 6 wk of culture than did steady-state CD34(+) PB cells of normal controls. Single-cell culture studies showed a substantial difference in the number of SCF-responsive or SCF+TPO-responsive mast cell progenitors in CD34(+) PB cells between the two groups. In the presence of TPO, CD34(+) PB cells from asthmatic children could respond to a suboptimal concentration of SCF to a greater extent, compared with the values obtained by those of normal controls. Six-week cultured mast cells of asthmatic subjects had maturation properties (intracellular histamine content and tryptase/chymase enzymatic activities) similar to those derived from mobilized CD34(+) PB cells of nonasthmatic subjects. An increase in a potential of circulating hemopoietic progenitors to differentiate into mast cell lineage may contribute to the recruitment of mast cells toward sites of asthmatic mucosal inflammation.
 ...
PMID:An increase in circulating mast cell colony-forming cells in asthma. 1125 27

In an attempt to identify novel diagnostic markers for mast cell (MC)-proliferative disorders, serial bone marrow (bm) sections of 22 patients with mastocytosis (systemic indolent mastocytosis, n = 19; mast cell leukemia [MCL], n = 1; isolated bm mastocytosis, n = 2) were analyzed by immunohistochemistry using antibodies against CD2, CD15, CD29, CD30, CD31, CD34, CD45, CD51, CD56, CD68R, CD117, HLA-DR, bcl-2, bcl-x(L), myeloperoxidase (MPO), and tryptase. Staining results revealed expression of bcl-x(L), CD68R, and tryptase in neoplastic MCs (focal dense infiltrates) in all patients. Mastocytosis infiltrates were also immunoreactive for CD45, CD117 (Kit), and HLA-DR. In most cases, the CD2 antibody produced reactivity with bm MCs in mastocytosis, whereas in control cases (reactive bm, immunocytoma, myelodysplastic syndrome), MCs were consistently CD2 negative. Expression of bcl-2 was detectable in a subset of MCs in the patient with MCL, whereas no reactivity was seen in patients with SIM or bm mastocytosis. Mastocytosis infiltrates did not react with antibodies against CD15, CD30, CD31, CD34, or MPO. In summary, our data confirm the diagnostic value of staining for tryptase, Kit, and CD68R in mastocytosis. Apart from these, CD2 may be a novel useful marker because MCs in mastocytosis frequently express this antigen, whereas MCs in other pathologic conditions are CD2 negative.
 ...
PMID:Immunohistochemical properties of bone marrow mast cells in systemic mastocytosis: evidence for expression of CD2, CD117/Kit, and bcl-x(L). 1138 74


1 2 3 4 5 6 7 8 Next >>