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Query: EC:1.11.1.7 (
peroxidase
)
65,474
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Enzymatic deacylation of LPS markedly reduces its activity in the dermal Shwartzman reaction. Inasmuch as polymorphonuclear leukocytes (PMN) are involved in the genesis of tissue injury in Shwartzman reactions, we have investigated the effects of deacylated LPS (dLPS) on PMN. Compared to LPS, dLPS was ineffectual as a stimulus of both PMN adherence and release of secondary granule enzymes, and dLPS inhibited specific LPS-induced adherence. Neither LPS nor dLPS caused release of the primary granule enzymes,
myeloperoxidase
, and elastase. Unlike LPS, dLPS failed to prime PMN for superoxide release when a second stimulus (FMLP, 10(-6) M was given. The mechanism of the LPS induced increase in PMN adherence was investigated, and we found that LPS significantly increased the amount of the adhesive glycoprotein
CD11b
on the surface of the PMN. dLPS had no effect on
CD11b
expression. Our results suggest that enzymatic deacylation of LPS profoundly alters its ability to stimulate PMN and deacylation of LPS by inflammatory cells in vivo might be an important mechanism limiting the toxic effects of LPS.
...
PMID:A comparison of the effects of intact and deacylated lipopolysaccharide on human polymorphonuclear leukocytes. 215 18
Plical tissue removed perioperatively from lumbar facet joints was studied immunohistochemically with the avidin-biotin-
peroxidase
complex (ABC) method for a putative presence of various subclasses of inflammatory cells and active collagen-producing fibroblasts. These methods have previously been used successfully for demonstrating specific inflammatory cells in rheumatoid arthritic synovium and cervical ligament and for studying regeneration of connective tissue, respectively. An overt inflammatory cellular response could not be demonstrated, as B lymphocytes were totally absent and no lymphocyte activation markers, either interleukin-2 receptor or immune-response-associated Ia antigens were expressed. Most of the immunoreactive cells observed were
CD11b
monocytes, and even these were only scattered in the connective tissue. Occasional activated collagen-producing fibroblasts were seen, suggesting in these few cases a possible regenerative response of the collagenous tissue, maybe induced by an impingement phenomenon, as such cells are not normally seen in resting connective tissue.
...
PMID:Immunohistochemical demonstration of subclasses of inflammatory cells and active, collagen-producing fibroblasts in the synovial plicae of lumbar facet joints. 219 96
During the course of differentiation of early human myeloid cells toward monocytes and granulocytes, cell surface expression of the cell adhesion molecule,
CD11b
/CD18 (Mo1) increases dramatically and expression of
myeloperoxidase
(
MPO
), a bacteriocidal enzyme, decreases markedly. Using the inducible promyelocytic cell line HL-60 as a model, we studied the mRNA expression of these genes. Differentiation of these cells along both a monocytic and a granulocytic pathway demonstrated that the mRNA levels of the two subunits of
CD11b
/CD18 increased in a pattern temporally and quantitatively similar to the increase in cell surface expression of this heterodimer. In contrast, the expression of
MPO
mRNA decreased in a temporal and quantitative pattern similar to the known decrease in
MPO
protein during differentiation, suggesting that regulation of these myeloid-specific proteins may occur at the level of mRNA expression. These findings have important implications with regard to the nature of the block in differentiation in acute nonlymphocytic leukemia and the regulation of myeloid gene expression.
...
PMID:Differential expression of CD11b/CD18 (Mo1) and myeloperoxidase genes during myeloid differentiation. 256 20
Biopsies obtained from both the perilesional areas and clinically uninvolved skin of patients with pemphigus vulgaris (PV) were studied for antigen-presenting cell and lymphocyte phenotype and/or activation phenotype using monoclonal antibodies in avidin-biotin-
peroxidase
complex staining. Perilesional PV skin contained CD4+ and CD8+ T lymphocytes as the predominant cell type, but cells with a potential antigen-presenting function displaying
CD11b
phenotype of monocyte/macrophages and, in particular, CD1 phenotype of Langerhans cells were also present. The number of mononuclear inflammatory cells was greater in perilesional than in clinically uninvolved PV skin, and so were the proportions of CD4+, CD8+, CD25+, Ia+ cells (p less than 0.01), and CD1+ Langerhans cells and transferrin receptor positive cells (p less than 0.05). These findings confirm and extend earlier observations on local involvement of immunocompetent cells in PV.
...
PMID:Local involvement of antigen-presenting cells and activated T cells in perilesional and clinically uninvolved skin in pemphigus vulgaris. 257 10
The purpose of this study is to show that anti-Leu M1 antibody (anti-CD15), which has different staining characteristics in lymphoid and non-lymphoid cells, reacted against the surface antigen of a defined monoclonal B cell line. This antibody recognizes the sugar moiety, lacto-N-fucopentaose (LNF-III), which is linked to the cell membrane protein in several kinds of cells, but not in B cells. However, a human monoclonal B-cell line (TKS-1) which was established from the peripheral blood of a patient with rheumatoid arthritis, expressed the Leu M1 antigen spontaneously. The analysis of surface markers using a fluorescence-activated cell sorter (FACS) has revealed that the surface markers of TKS-1 were anti-mu, delta, kappa, HLA-DR, DQ, Leu 12 (CD19) and Leu M1 (CD15). TKS-1 cells were not reactive with any of the following antibodies: anti-OK M1 (
CD11b
), Leu M2, Leu M3 (CD14), Leu M4, Leu 1 (CD5), Leu 2 (CD8), Leu 3 (CD4), Leu 4 (CD3), Leu 7 and Leu 11 (CD16). In addition, TKS-1 was positive to Epstein-Barr nuclear antigen, weakly positive to non-specific esterase without staining inhibition by NaF, and negative to
peroxidase
. TKS-1 cells produced IgM in the culture supernatant and have kappa-light chain rearrangement in its DNA. As shown in other studies, distribution of Leu M1 is very wide. This antigen is not a specific immunodiagnostic marker to distinguish the cell type. We conclude that it is possible to express Leu M1 antigen on the membrane of a B-cell lineage cell.
...
PMID:Expression of Leu M1 antigen on a monoclonal B cell line established from a patient with rheumatoid arthritis. 257 80
The S-100-positive T lymphocytes, and, particularly, the S-100 beta subunit, are restricted, as demonstrated by quantitative subset analysis and double-labeling (gold-
peroxidase
) immunoelectron microscopy of T-cell subpopulations, to an unique T8-positive cell subset which interestingly was 9.3-negative and
CD11b
-positive. Since both the T8-positive, 9.3-negative and the T8-positive,
CD11b
-positive subpopulations have been demonstrated to show suppressive activities, the S-100-positive T cells seem to be closely restricted to a small T-suppressor-cell compartment. Although functional studies on viable isolated S-100 beta-positive cells are impossible to achieve, due to the lack of this protein on the cell membrane, its presence in a discrete T-suppressor compartment might suggest a possible role for the S-100 beta-positive T cells in the regulation of the immune system.
...
PMID:The S-100 beta protein in normal human peripheral blood is uniquely present within a discrete suppressor-T-cell compartment. 296 45
We studied the clinical and biologic features of 10 cases of acute leukemia that met standard French-American-British (FAB) criteria for acute myeloid leukemia (AML) but in which the blast cells also expressed the T-cell-associated CD2 surface antigen. All cases had greater than 3%
myeloperoxidase
and Sudan black B-positive leukemic blasts, and blasts from seven cases contained Auer rods. Reactivity of the cells with a panel of monoclonal antibodies (MAbs) indicated that leukemic cells in all cases expressed myeloid-associated (
CD11b
, CD13) surface antigens, further supporting the diagnosis of AML. However, blasts from every patient coexpressed the T-cell-associated surface CD2 and CD7 as well as cytoplasmic CD3 antigens. Blasts from five patients expressed surface CD25, whereas blasts from only one expressed surface CD3. Five patients had rearranged T-cell receptor beta-chain genes, whereas only three had rearranged T-cell receptor gamma-chain genes. This pattern of lineage-related gene expression appears to define a distinct subtype of AML with T-lymphoid features (CD2+ AML) and could reflect either aberrant gene expression in leukemic blasts or transformation of a pluripotent stem cell having a flexible pattern of gene expression. Clinically, these 10 patients presented at an older age with a higher leukocyte count and a higher frequency of lymphadenopathy than did children whose blast cells were characteristic of myeloid leukemia. Patients with CD2+ AML also had poorer responses to remission induction therapy (50% v 80% entered complete remission, P = .05). However, each of the five children who failed induction chemotherapy on AML protocols had a striking response to drug combinations usually reserved for lymphoid leukemia. We conclude that this leukemia with mixed lymphoid and myeloid characteristics is a distinct biologic and clinical entity.
...
PMID:Acute myeloid leukemia with T-lymphoid features: a distinct biologic and clinical entity. 326 Nov 83
Using an in vitro expansion and differentiation system for human CD34+ cord blood (CB) progenitor cells, we analyzed the induction and expression kinetics of the granulomonocyte associated lysosomal proteins
myeloperoxidase
(
MPO
), lysozyme (LZ), lactoferrin (LF), and macrosialin (CD68). Freshly isolated CD34+ CB cells were negative for LZ and LF, and only small proportions expressed
MPO
(4% +/- 2%) or CD68 (3% +/- 1%). Culturing of CD34+ cells for 14 days with interleukin (IL)-1, IL-3, IL-6, stem cell factor, granulocyte-macrophage colony-stimulating factor (GM-CSF), and G-CSF resulted in on average a 1,750-fold amplification of cell number, of which 83% +/- 7% were MPO+. Without addition of GM-CSF and G-CSF, lower increases in total cell numbers (mean, 211-fold) and lower proportions of MPO+ cells (54% +/- 11%) were observed. The proportion of MPO+ cells slightly exceeded but clearly correlated with the proportion of cells positive for the granulomonocyte associated surface molecules
CD11b
(Mac-1), CD15 (LeX), CD64 (Fc gamma RI) CD66, or CD89 (Fc alpha R). At day 14 MPO+ and LZ+ cells were virtually identical. However, at earlier time points during culture (days 4 and 7), single MPO+ or LZ+ cell populations were also observed, which only later acquired LZ and
MPO
, respectively. Maturation of cells into the neutrophilic pathway was indicated by the acquisition of
MPO
, followed by LZ. In contrast, maturation of cells into the monocytic pathway was indicated by the acquisition of LZ followed by
MPO
and CD14. CD68 was found to be expressed at day 4 by the majority of cells and was not restricted to the granulomonocytic cells, as cells with megakariocytic (CD41+) or erythroid (CD71hi) features were CD68+. LF expression was observed only in GM- plus G-CSF-supplemented cultures, in which only 26% +/- 5% of cells expressed LF by day 14.
...
PMID:Granulomonocyte-associated lysosomal protein expression during in vitro expansion and differentiation of CD34+ hematopoietic progenitor cells. 749 68
Ischemia (4-hour) followed by reperfusion (4-hour) of rat hind limbs results in local injury as well as remote (lung) injury. It has recently been shown that injury in this model is neutrophil- and cytokine-dependent and requires the beta 2 integrin adhesion molecules CD11a/CD18 and
CD11b
/CD18. The role of selectins in events leading to injury (as determined by leakage of albumin and by hemorrhage) was assessed either through the use of blocking antibodies to L-, E- or P-selectins or by the use of oligosaccharides that are reactive with selectins. Lung injury was found to be L- and E-selectin-dependent. When the ischemia and reperfusion times were reduced, lung injury was also found to be P-selectin dependent. In the case of hind limb injury involving the crural muscle mass, injury was L-selectin-dependent but independent of requirements for P- and E-selectin. Injury in both organs was blocked by the infusion of sialylated Lewis pentasaccharide, whereas sialyl-N-acetyllactosamine pentasaccharide failed to protect against injury. In general, when selectin-blocking approaches were protective, there were parallel reductions in tissue content of
myeloperoxidase
. These data underscore the role of selectins in ischemia-reperfusion injury and suggest that selectin requirements may vary with the vascular bed under study.
...
PMID:Role of selectins in local and remote tissue injury following ischemia and reperfusion. 751 Apr 57
Acute second degree thermal injury of rat skin involving 25 to 30% total body surface of anesthetized rats results at 4 hours in evidence of vascular injury both locally (in skin) and remotely (involving lung). The neutrophil dependency for both types of injury has now been established. Monoclonal antibodies to various adhesion molecules have been used to define the requirements for these molecules in the development of vascular injury. In dermal vascular injury, a requirement for Mac-1 (
CD11b
/CD18) but not for leukocyte function-associated antigen-1 (LFA-1, CD11a/CD18) has been established. In this model requirements have also been demonstrated for intercellular adhesion molecule-1 (ICAM-1) and E- and L-selectin but not for very late arising antigen-4 (VLA-4) or P-selectin. With respect to lung vascular injury, dual requirements for both leukocyte function-associated antigen-1 and Mac-1 were found as well as for ICAM-1 and E- and L-selectin but not for VLA-4 and P-selectin. In the lung, there was a close correlation between neutrophil content of the tissue (as assessed by
myeloperoxidase
) and the effects of protective interventions (directed against blocking of adhesion molecules). These data emphasize the roles of beta 2 integrins, selectins (L and E), and ICAM-1 in events that lead to neutrophil-mediated vascular injury of dermis and lung after thermal trauma to skin.
...
PMID:Role of leukocyte adhesion molecules in lung and dermal vascular injury after thermal trauma of skin. 751 48
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