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:3.2.1.17 (lysozyme)
21,489 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The involvement of tyrosine phosphorylation in insulin action led us to hypothesize that increased activity of protein tyrosine phosphatases (PTPases) might contribute to insulin resistance in alloxan diabetes in the rat. Hepatic PTPase activity was measured using two artificial substrates phosphorylated on tyrosine: reduced, carboxyamidomethylated, and maleylated lysozyme (P-Tyr-RCML) and myelin basic protein (P-Tyr-MBP), as well as an autophosphorylated 48-kD insulin receptor tyrosine kinase domain (P-Tyr-IRKD). Rats that were made alloxan diabetic exhibited a significant increase in hepatic membrane (detergent-soluble) PTPase activity measured with P-Tyr-MBP, without a change in activity measured with P-Tyr-RCML or the P-Tyr-IRKD. The PTPase active with P-Tyr-MBP behaved as a high molecular weight peak during gel filtration chromatography. Characterization of this enzyme indicated it shared properties with CD45, the prototype for a class of transmembrane, receptor-like PTPases. Our results indicate that alloxan diabetes in the rat is associated with an increase in the activity of a large, membrane-associated PTPase which accounts for only a small proportion of insulin receptor tyrosine dephosphorylation. Nonetheless, increased activity of this PTPase may oppose tyrosine kinase-mediated insulin signal transmission, thus contributing to insulin resistance.
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PMID:Differential regulation of multiple hepatic protein tyrosine phosphatases in alloxan diabetic rats. 132 40

A grave prognosis is usually associated with leukemic skin infiltrates (leukemia cutis). However, some leukemic skin infiltrates are clinically similar to reactive non-leukemic infiltrates in patients with leukemia; thus it is of great importance to distinguish them. Fifty-four cases which were thought clinically to be leukemia cutis underwent immunophenotyping with a panel of nine T, B, monocytic, and macrophage markers using paraffin sections. Immunohistochemistry helped identify 44 cases with leukemia cutis and 10 with reactive infiltrates. In all cases of leukemia cutis, the staining patterns of skin infiltrates were concordant with cell type in the bone marrow. Furthermore, the panel of markers was usually helpful in distinguishing reactive from leukemia infiltrates, especially in cases with chronic lymphatic leukemia. Immunohistochemistry is a valuable adjunct in histopathologic differentiation of skin infiltrates in most cases of leukemia. With formalin-fixed, paraffin-embedded biopsies, we recommend that CD45 (LCA), CD45RO (UCHL-1), CD3, CD20 (L-26), CD43 (Leu-22), CD68 (KP-1), lysozyme, and chloroacetate esterase be considered in cases of systemic leukemia with cutaneous papules and nodules that prove difficult to interpret with routine section.
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PMID:Value of immunohistochemistry in the diagnosis of leukemia cutis: study of 54 cases using paraffin-section markers. 138 98

To provide baseline information on the immunoarchitecture of normal bone marrow, we studied cryostat-cut, frozen, and paraffin-embedded, fixed tissue sections prepared from 21 core biopsies of normal bone marrow obtained during bone marrow harvests for transplantation. A large panel of antibodies was applied that included, for frozen tissue, Leu-6 (CD1), T11 (CD2), Leu-3a (CD4), Leu-1 (CD5), Leu-2a (CD8), J5 (CD10), My7 (CD13), Leu-11 (CD16), B4 (CD19), B1 (CD20), B2 (CD21), Tac (CD25), My9 (CD33), T200 (CD45), NKH-1 (CD56), kappa and lambda chains, beta F1, Ki-67, HLA-DR, TQ1, and keratin, and for fixed tissue, leukocyte common antigen (CD45), L26 (CD20), LN1 (CDw75), LN2 (CD74), LN3, LN4, LN5, MB1 (CD45R), MB2, MT1 (CD43), MT2 (CD45R), UCHL1 (CD45R0), BM1, Ki-1 (CD30), Leu-M1 (CD15), lysozyme, KP1 (CD68), actin, S100, neuron-specific enolase, vimentin, and keratin. On fresh-frozen sections CD19 and CD2 were the most reliable and sensitive markers for B and T cells, staining 5% and 9% of marrow cells, respectively. Immunoglobulins generally showed heavy background staining, which frequently precluded an accurate assessment. The CD4 to CD8 ratio in the bone marrow was reversed from that of peripheral blood. On fixed tissues, leukocyte common antigen was found in 14% of the marrow cells, corresponding roughly to the lymphocyte population. L26, a pan-B-cell marker, stained 3% of the marrow cells. Among the other B-cell markers, LN1 and MB2 stained a large number of cells (40% to 70%), indicating reactivity with cells of the myeloid or erythroid series in addition to lymphocytes. Among the T-cell markers, UCHL1 and MT1 stained 66% and 50% of the cells, respectively, which could be explained by their cross-reactivity with myeloid cells. Nonspecific myelomonocytic markers (Leu-M1, KP1, and lysozyme) also showed reactivity in a high percentage of cells. No particular architectural distribution patterns of B or T lymphocytes were noted in either frozen or fixed bone marrow specimens. The results of this study provide normal baseline data for the immunohistologic application of hematopoietic and lymphoid markers on frozen or fixed bone marrow biopsy specimens.
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PMID:Immunoarchitecture of normal human bone marrow: a study of frozen and fixed tissue sections. 159 93

Ligation of interleukin 2 (IL2) is known to regulate both protein tyrosine and serine/threonine phosphorylation. A family of leukocyte transmembrane proteins whose cytoplasmic domain exhibits intrinsic protein tyrosine phosphatase activity is collectively called CD45 and is identified by a set of common cell surface epitopes. Although CD45 is known to be a phosphoprotein, it is not known how phosphorylation specifically regulates its function. We therefore identified a cell line, the IL4-dependent line CTLL-2.4, in which CD45 could be phosphorylated in response to addition of IL2. These cells are a variant of an IL2-dependent murine cell line which were selected for long-term growth on IL4 but which retain the ability to proliferate on exposure to IL2. Incubation of CTLL-2.4 in low serum concentrations followed by stimulation with IL2 caused a three- to fivefold increase in the phosphorylation of CD45 in a time- and concentration-dependent manner. CD45 in non-stimulated cells contained one major tryptic phosphopeptide, whereas, after exposure of the cells to IL2, two new phosphopeptides were present in CD45. The pattern of IL2-induced phosphorylation was different from that found following addition of phorbol 12-myristate 13-acetate (PMA) to the cells. Although IL2 induced rapid and potent tyrosine phosphorylation in CTLL-2.4 cells, all of the basal and cytokine-activated phosphorylation of CD45 occurred on serine residues. The IL2-stimulated phosphorylation caused no change in the amount of cell surface CD45 and no alteration of its catalytic activity using an artificial tyrosine phosphorylated substrate-RCM-lysozyme. We speculate that the increase in phosphorylation of CD45 may modify its association with potential substrates. The differences in the phosphorylation patterns induced by IL2 and PMA further suggest that more than one kinase can use CD45 as substrate and that IL2 activates a protein serine/threonine kinase different from protein kinase C.
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PMID:Interleukin 2 stimulates serine phosphorylation of CD45 in CTLL-2.4 cells. 185 Mar 60

An immunophenotype was performed on an osteoclast-like giant cell tumor of the pancreas using a panel of antibodies to epithelial and leukocyte antigens. Several antibodies to cytokeratin and carcinoembryonic antigen were negative in the tumor. Osteoclast-like cells were positive for CD4, CD13, CD45, CD68, CD71, and vimentin, but negative for lysozyme and HLA-DR. Mononuclear tumor cells were positive for CD4, CD11c, CD13, CD14, CD45, CD68, CD71, HLA-DR, and vimentin, but negative for lysozyme. The phenotype is similar to that previously described for giant cell tumor of bone. The osteoclast-like cell phenotype is also similar to that reported for normal osteoclasts. The findings support a nonepithelial origin for osteoclast-like giant cell tumor of the pancreas, and suggest a derivation similar to giant cell tumor of bone.
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PMID:Osteoclast-like giant cell tumor of the pancreas: immunophenotypic similarity to giant cell tumor of bone. 186 95

A panel of monoclonal antibodies (anti-CD45 [common leukocyte antigen], Ki-B3, L26, MT1, UCHL1, anti-CD15 [X-hapten], anti-neutrophil granule protein elastase [NP57]), anti-lysozyme, and the naphthol-ASD-chloroacetate reaction were applied to two cases of granulocytic sarcoma (GS) for evaluation of their utility in differentiating GS from malignant lymphoma. Lysozyme and naphthol-ASD-chloroacetate esterase were found to be the most reliable markers for detection of the myeloid nature of the tumour cells. GS infiltrated solely the mucosa of the nasal cavity in one case, while in the other it involved both the nasal cavity and maxillary sinus with simultaneous eruptions on the skin of the trunk. In both cases, peripheral blood and bone marrow findings were inconspicuous at the time of diagnosis of GS.
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PMID:Immunohistochemical differential diagnosis of granulocytic sarcomas and malignant lymphomas on formalin-fixed material. 210 52

Although CD45 resembles the low Mr protein tyrosine phosphatases (PTPases) from human placenta in its specificity for phosphotyrosyl residues and absolute dependence on sulfhydryl compounds for activity, it also exhibits a number of distinguishing features. Most notably, it displayed substrate specificity in vitro, preferentially dephosphorylating myelin basic protein, over the other substrates tested, with high specific activity. Limited trypsinization of CD45 generated active fragments of approximately 65 kDa that were apparently derived exclusively from the intracellular segment of the molecule. These retained high activity against myelin basic protein, suggesting that this is an intrinsic feature of the PTPase domains and not the result of secondary interactions between the substrate and the putative ligand binding structure. With reduced carboxamidomethylated and maleylated lysozyme as substrate, CD45 was stimulated up to 12-fold by basic compounds such as spermine; divalent metal ions were also stimulatory, most notably Zn2+, which was previously identified as a potent inhibitor of the low Mr PTPases. CD45 was phosphorylated to high stoichiometry by casein kinase-2 (up to 1.5 mol/mol) and also by glycogen synthase kinase 3 (approximately 0.3 mol/mol) and protein kinase C (approximately 0.1 mol/mol); in all cases, no alteration in enzyme activity was detected following these modifications. Autophosphorylated preparations of epidermal growth factor receptor, insulin receptor, and p56lck protein tyrosine kinases were also substrates for CD45 in vitro.
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PMID:CD45, an integral membrane protein tyrosine phosphatase. Characterization of enzyme activity. 216 57

Several immunohistochemical methods are now available for the staining of neoplastic cells in tissue sections. The authors have found that the alkaline phosphatase-anti-alkaline phosphatase (APAAP) method is sensitive and reliable. Murine monoclonal or nonmurine polyclonal antibodies can be used to label a variety of membranous and/or cellular constituents in tissues that have been routinely processed in a histopathology laboratory. The monoclonal antibody against leukocyte common antigen (CD45) can be used to differentiate hematologic from nonhematologic tumors. Monoclonal antibodies (L26, LN1, LN2, LN3, MB1, MB2) label B-cell lymphomas, whereas other monoclonal antibodies (UCHL1, MT1) more characteristically stain T-cell lymphomas. Polyclonal antibodies against CD3 specifically mark neoplastic cells from T-cell lymphomas and leukemias but as yet are not commercially available. Monoclonal antibodies Leu-M1 (CD15), Ber H2 (Ki-1; CD30), and LN2 label Reed-Sternberg cells from most cases of nodular sclerosis, mixed cellularity, and lymphocyte-depleted Hodgkin's disease. Monoclonal antibodies Mac 387, KP1 (CD68), and NP57 (antielastase), as well as polyclonal antibodies against lysozyme, help identify subtypes of acute myeloid leukemia and extramedullary myeloid cell tumors. Although there are now excellent reagents ready for use, there is still a significant need for more lineage-specific (particularly against CD epitopes) monoclonal antibodies capable of labeling neoplastic cells in paraffin-embedded tissue sections from patients with hematologic malignancies.
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PMID:Immunophenotyping of hematologic neoplasms in paraffin-embedded tissue sections. 218 Feb 77

The clinical association of lymphomatoid papulosis and Hodgkin's disease and the striking morphologic similarity of atypical cells in lymphomatoid papulosis to Reed-Sternberg cells in Hodgkin's disease suggest that lymphomatoid papulosis and Hodgkin's disease are related. To test this possibility we studied the antigenic profile of Reed-Sternberg cells in the lymph nodes and of atypical cells in cutaneous lesions of lymphomatoid papulosis in two patients with Hodgkin's disease and lymphomatoid papulosis. In paraffin sections both cell types expressed CD30, CD45 T cell-restricted antigens, and occasionally CD15 antigens. They were negative for CD45 B cell-restricted antigens and for lysozyme. In cutaneous lymphomatoid papulosis lesions a similar immunologic profile of the atypical cells was found; that is, they were positive for CD30, CD2, CD3, and CD25 but negative for B cell and macrophage antigens. The similarity of the immunophenotype of Reed-Sternberg cells in lymph nodes affected by Hodgkin's disease and the immunophenotype of atypical cells of lymphomatoid papulosis lesions in the same patients suggests that the malignant cells in both conditions are derived from activated T cells and that they are closely related if not identical.
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PMID:Hodgkin's disease followed by lymphomatoid papulosis. Immunophenotypic evidence for a close relationship between lymphomatoid papulosis and Hodgkin's disease. 237 Mar 46

Previous studies have shown that monoclonal antibody 60.3 reacting with a surface antigen common to human leukocytes inhibits phorbol ester-induced adhesion among blood mononuclear cells and precipitates from these cells three surface polypeptides with apparent molecular weights of 90,000, 130,000 and 160,000. Now we report that the same antibody, either as purified IgG or Fab fragments, also inhibits the extensive adhesion among granulocytes induced by phorbol ester. Inhibition of cell aggregation was not observed with monoclonal antibodies to C3b receptor, common leukocyte antigen T200, C3bi receptor, brain granulocyte-T lymphocyte antigen, IgG Fc receptor, class I transplantation antigen, or a granulocyte-specific antigen. Intercellular adhesion induced by either the chemotactic tripeptide N-formylmethionyl-leucyl-phenylalanine (FMLP) or the ionophore A23187 was also inhibited by antibody 60.3. However, this antibody did not affect phorbol ester-induced superoxide (O2-) generation or lysozyme release. Two major surface glycopolypeptides with apparent molecular weights of 92,000 and 155,000 were immunoprecipitated from granulocytes. Dissociation of the protein complexes obtained from blood mononuclear cells and granulocytes indicated the presence of the epitope on the 90,000-92,000 molecular-weight components. It is thus concluded that the smallest glycopolypeptides mediate adhesion in human granulocytes and mononuclear leukocytes.
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PMID:Identification of a cell-surface glycoprotein mediating adhesion in human granulocytes. 241 94


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