Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.21.4 (trypsin)
42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Mesenchymal stem cells (MSCs) have been isolated based on the ability of adherence to plastic surfaces. The potential of these cells to differentiate along multiple lineages is the key to identifying stem cell populations in the absence of molecular markers. Here we describe a homogenous population of MSCs from mouse bone marrow isolated using a relatively straightforward and novel approach. This method is based on the combination of frequent medium change (FMC) and treatment of the primary cultures with trypsin. Cells isolated using this method demonstrated the MSCs characteristics including their ability to differentiate into mesenchymal lineages. MSCs retained the differentiation potentials in expanded cultures up to 10 passages. Isolated MSCs were reactive to the CD44, Sca-1, and CD90 cell surface markers. MSCs were negative for the hematopoietic surface markers such as CD34, CD11b, CD45, CD31, CD106, CD117 and CD135. The data presented in this report indicated that this method can result in efficient isolation of homogenous populations of MSCs from mouse bone marrow.
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PMID:An efficient method for isolation of murine bone marrow mesenchymal stem cells. 1793 19

Interstitial cells of Cajal (ICC) are well described in the bowel wall. They are c-kit positive and play a role as pacemaker cells. Similar c-kit-positive cells have recently been described in the human bladder. The aim of this study was to characterize interstitial cells of the bladder detrusor using a panel of antibodies directed against CD117/c-kit, CD34, CD31, S100, tryptase, neurofilament, NSE, Factor-VIII and GFAP. A striking finding was an interstitial type of cell which is CD34 immunoreactive (CD34-ir) but CD117/c-kit negative. The cells have a tentacular morphology, enveloping and intermingling with individual muscle fasicles. Morphologically and immunohistochemically, they show no neurogenic, endothelial or mast cell differentiation. Transmission electron microscopy (TEM) showed the presence of interstitial cells with a round-to-oval nucleus, sparse perinuclear cytoplasm and long flattened processes, ramifying primarily in a bipolar fashion. Using immunoelectron microscopy (I-TEM) it was possible to view CD34 gold labelling of cells corresponding to interstitial cells. Although similar CD34-positive cells have been demonstrated in the bowel wall, they have never been described in the detrusor. The ontogeny and function of CD34-ir, a kit-negative cell, is unknown, but it may be involved in smooth muscle contraction.
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PMID:CD34-positive interstitial cells of the human detrusor. 1809 58

Interstitial Cajal-like Cells (ICLC) were recently recognized in a plethora of non-digestive organs. Here, we describe a cell type of rat mesentery sharing ultrastructural and immunohistochemical features with ICLC. Mesenteric ICLC were demonstrated by transmission electron microscopy (TEM) and further tested by light microscope immunohistochemistry. The cell described here fulfils the TEM diagnostic criteria accepted for ICLC: location in the connective interstitium; close vicinity to nerves, capillaries and other interstitial cells; characteristic long, moniliform cell processes; specialized cell-to-cell junctions; caveolae; mitochondria at 5-10% of cytoplasmic volume; rough endoplasmic reticulum at about 1-2%; intermediate and thin filaments, microtubules; undetectable thick filaments. The processes of this mesenteric ICLC were particularly long, with a mean length of 24.91 microm (10.27-50.83 micorm), and a convolution index of 2.32 (1.37-3.63) was calculated in order to measure their potential length. Mean distances versus main target cells of ICLC-nerve bundles, vessels, adipocytes and macrophages-were 110.69, 115.80, 205.07 and 34.65 nm, respectively. We also tested the expression of CD117/c-kit, CD34, vimentin, alpha-smooth muscle actin, nestin, NK-1, tryptase and chymase and the antigenic profile of the mesenteric ICLC was comparable if not identical with that recently observed in ICLC from other extra-digestive tissues. Due to the peculiar aspect of the mesenteric ICLC processes it can be hypothesized that these cells form a three-dimensional network within the mesentery that is at the same time resistant and deformable following stretches consequent to intestine movements, mainly avoiding blood vessels closure or controlling blood vessels rheology. It remains, however, to be established if and how such cells are connected with the archetypal enteric ICC.
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PMID:Interstitial Cajal-like cells in rat mesentery: an ultrastructural and immunohistochemical approach. 1819 43

Although IL-3 is commonly used for culture of human progenitor-derived mast cells together with Stem cell factor (SCF) and IL-6, the effect of IL-3 on human mast cell differentiation has not been well elucidated. Human bone marrow CD34+ progenitors were cultured for up to 12 weeks in the presence of rhSCF and rhIL-6 either with rhIL-3 (IL-3 (+)) or without rhIL-3 (IL-3 (-)) for the initial 1-week of culture. Total cell number increased at 2 weeks in IL-3 (+), as compared to IL-3 (-), but changes in the appearance of mast cells were delayed. When IL-3 was present for the initial 1-week culture, granules looked more mature with IL-3 than without IL-3. However, tryptase and chymase contents, and surface antigen expression (CD18, CD51, CD54, and CD117) were not altered by IL-3. Surface expression and mRNA level of FcepsilonRIalpha and histamine release by crosslinking of FcepsilonRIalpha did not differ from one preparation to the next. GeneChip analysis revealed that no significant differences were observed between IL-3 (+) and IL-3 (-) cells either when inactivated or activated by aggregation of FcepsilonRIalpha. These findings indicate that initial incubation of human bone marrow CD34+ progenitors with IL-3 does not affect the differentiation of mast cells.
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PMID:Interleukin-3 does not affect the differentiation of mast cells derived from human bone marrow progenitors. 1821 96

The expression of c-kit, a protooncogene tyrosine kinase receptor (CD117), in phyllodes tumors of the breast has been the subject of recent investigations. We examined stromal c-kit expression by immunohistochemistry in 68 cases comprising fibroadenomas, fibroadenomas with cellular stroma, and benign, borderline, and malignant phyllodes tumors. Membrane staining was identified in the epithelium of 82% of cases, representing all diagnostic categories in the study. Membrane and cytoplasmic staining was detected in scant cells in the stroma in 74% of the cases in the study, again, across all diagnostic entities. However, when toluidine blue and tryptase staining was performed, the staining pattern matched that of c-kit in the number of cells and their distribution, thereby confirming the presence of mast cells and excluding any appreciable level of true stromal c-kit staining. One borderline and one malignant phyllodes tumor showed a diffuse weak stromal signal, which could not be accounted for by toluidine blue and tryptase. These cases were further tested for the presence of known activating mutations of c-kit and PDGFR-alpha, and yielded negative results. Our findings indicate that c-kit is an unlikely player in the pathogenesis of fibroepithelial lesions of the breast. The positive stromal staining suggested previously by other authors may be attributed to mast cells. C-kit, therefore, has neither a diagnostic nor a prognostic role in phyllodes tumors, and there is no rationale for the treatment of recurrent of malignant phyllodes tumor patients with tyrosine kinase inhibitors.
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PMID:Expression of c-kit in fibroepithelial lesions of the breast is a mast cell phenomenon. 1850 Feb 66

During the last two decades different scientific groups have investigated the phenotype and function of in vitro generated human mast cells (MC). The cells have been shown to display variable surface markers and functional characteristics. The phenotypic differences may reflect different culture conditions, protocols or the use of different progenitors. To investigate the significance of different progenitors, we have compared MC generated from CD133(+) progenitor cells from cord blood (CBMC) or peripheral blood (PBMC). The progenitors were cultured for 7 weeks in the presence of IL-6 and SCF, with addition of IL-3 the first 3 weeks, and FCS during week 7. The phenotype of the established MC was characterized by surface marker expression levels, metachromasia, histamine and tryptase contents and their function was evaluated by receptor-mediated release of histamine and PGD(2). The generated metachromatic (<99%) MC were 75% tryptase(+), regardless of the source of progenitor cell. Expression of c-kit/CD117, CD203c, and FcepsilonRI was comparable. The density of c-kit/CD117 receptors on CBMC was higher that of PBMC (p<0.001). The density of CD203c and FcepsilonRI was higher on PBMC (p<0.001). PBMC contained more histamine (p<0.001), expressed more FcepsilonRI (p<0.001) and released more histamine (p<0.001) and PGD(2) (p<0.001) upon ligation of FcepsilonRI, than CBMC. Culture with IL-4 increased expression of tryptase, FcepsilonRI, CD117 and CD203c, secretion of histamine and PGD(2) of PBMC, and histamine secretion of CBMC. Cord and peripheral blood may give rise to different types of MC. The question addressed should determine the progenitor cell and protocol to be used.
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PMID:Comparison of short term in vitro cultured human mast cells from different progenitors - Peripheral blood-derived progenitors generate highly mature and functional mast cells. 1853 84

Mast cells (MCs) have important functional roles in leukocyte recruitment, pain, and wound healing, and increased tissue resident MC function has been associated with several fibrotic diseases. Consequently, the study of MCs in situ can be a direct approach to studying the pharmacodynamic impact of MC-directed therapeutics in tissues. Here we describe an automated laser scanning cytometry assay that was used to characterize the kinetics of MC accumulation in healing skin wounds and to study the effect of inhibiting CD117 (cKit) signaling. The number of tryptase-positive MCs approximately doubled 14 days after cutaneous injury in nonhuman primates. Treatment of animals with anti-CD117 or imatinib mesylate (Gleevec) reduced MC accumulation at the edge of healing wounds in mice and nonhuman primates, respectively. In translating this MC assay to become a biomarker for human studies, no differences in dermal MC numbers were evident between genders, ages or body mass index from 20 healthy donors. These data suggest that skin is a practical and useful tissue for tracking pharmacodynamic effects of MC-directed therapies.
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PMID:Antagonists of CD117 (cKit) signaling inhibit mast cell accumulation in healing skin wounds. 1893 42

Increased numbers of mast cells (MCs) in the testis have been associated with testicular dysfunction, where accumulation of MCs occurs. Furthermore, it has been reported that MCs might affect sperm function as it has been demonstrated that MC-derived tryptase in the seminal fluid might reduce sperm motility. Although MCs have been detected in rat epididymis, only little is known about the presence of MCs in human seminal plasma. Thus, we analysed MC numbers in the ejaculate of men during routine semen analysis of male patients suspected for infertility (n = 100). MCs were detected by c-kit (CD117) expression using flow cytometry. Thereby, we detected significant numbers of MCs in the ejaculate of most patients (559 +/- 525 MCs ml(-1), mean +/- SD). However, we could neither detect a correlation with respect to MCs and sperm count, motility or morphology nor to the seminal inflammatory markers like polymorphonuclear elastase. Nevertheless, a significant correlation of MCs to spermatozoa-bound IgA (r = 0.5; P = 0.03; n = 21) was observed. It is concluded that significant numbers of MCs can be detected in the human ejaculate without necessarily influencing sperm function. A potential role of MCs in seminal plasma as well as the association between MCs and IgA on spermatozoa remains to be elucidated.
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PMID:Mast cells in the seminal plasma of infertile men as detected by flow cytometry. 1914 22

Atypical fibroxanthoma (AFX) is a rare skin tumor that generally pursues an indolent course despite its alarming histological appearances. It is important for the pathologist to distinguish this neoplasm from more aggressive lesions that may show very similar histological features. Recently, it has been suggested that demonstration of CD117 is of value in identifying AFX. To test this hypothesis, 50 cases of AFX were stained immunohistochemically for CD117 to determine the diagnostic value of this antibody. Cases were also stained for tryptase to identify mast cells, which are CD117 positive. In addition, S100 and CD1a stains were performed to assess any possible contribution of melanocytes or Langerhans cells to CD117 staining. Only 1 of 50 AFXs (2%) showed CD117 positivity in the neoplastic cells, but all tumors demonstrated included CD117- and tryptase-positive mast cells in similar distribution. CD117 is only rarely stainable in the neoplastic cells of AFX and is therefore not useful in identifying these tumors. Mast cells are also CD117 positive, frequently present in AFX, and can lead to misinterpretation. Using immunohistochemistry for mast cell tryptase may be of value where there is doubt as to the nature of CD117-positive cells in neoplasms.
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PMID:CD117 is not a useful marker for diagnosing atypical fibroxanthoma. 2052 72

Mastocytosis, an unusual disorder of bone marrow-derived, clonally transformed hematopoietic progenitor cells, exhibits a broad spectrum of clinical and morphologic features ranging from a self-limiting benign disorder (ie, juvenile cutaneous mastocytosis) to highly aggressive neoplasms like mast cell leukemia. Principally, mastocytosis should be divided in 2 main subentities: cutaneous mastocytosis and systemic mastocytosis mainly involving the bone marrow. Mastocytosis is a morphologic diagnosis and should not be diagnosed on the basis of clinical findings alone. Pathologists need to be aware of the disease and its mimickers. Application of the defined diagnostic criteria can confirm or exclude mastocytosis in most cases. Use of antibodies against tryptase, CD117 (KIT), and CD25 is recommended in every suspected case. Because most cases of systemic mastocytosis show a very low degree of infiltration of the bone marrow, antitryptase and anti-CD117 are of major importance for screening and quantification of mast cells, in particular to detect even small compact infiltrates as the only major diagnostic criterion for mastocytosis. Expression of CD25 on mast cells is defined as a minor diagnostic criterion and is usually seen only in mastocytosis but not in reactive states of mast cell hyperplasia.
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PMID:Mastocytosis: an unusual clonal disorder of bone marrow-derived hematopoietic progenitor cells. 1968 20


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