Cell surface receptors for kidney basement membranes.
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Basement Membrane↗
Biomedical subjects
L W Heck
Publications and source records attributed to L W Heck.
The bioflavonoid quercetin inhibits neutrophil degranulation, superoxide production, and the phosphorylation of specific neutrophil proteins.
Quercetin, a C-kinase antagonist, inhibits neutrophil degranulation and superoxide production induced by f-met-leu-phe, solid phase IgG, zymosan treated serum and a phorbol ester (PMA). Quercetin is more effective in inhibiting degranulation (IC50 = 20 uM) than superoxide production (IC50 = 80 microM). Neutrophil activation by PMA is accompanied by the phosphorylation of neutrophil proteins of 205, 170, 130, 91, 77, 67, 56, 47, 39, 34, 27, and 20 kilodaltons; quercetin also inhibits the phosphorylation of these proteins. Dose-response studies indicated that phosphorylation of the 67 kilodalton protein was particularly sensitive to inhibition by quercetin at concentrations that also inhibit neutrophil degranulation and superoxide production. These results suggest that phosphorylation of the 67 kilodalton protein may be an important intracellular reaction associated with neutrophil activation.
Adult↗
A low molecular weight, heat-labile factor enhances neutrophil Fc receptor-mediated lysosomal enzyme release and phagocytosis.
When exposed to solid-phase immune complexes, polymorphonuclear neutrophils (PMN) degranulate and release proteases capable of degrading the major structural macromolecules of the joint. Evidence indicates that the PMN response to such activators may be modified by factors present at the sites of inflammation. We have evaluated the effects of a low molecular weight factor present in synovial fluid from rheumatoid arthritis (RA) patients on Fc receptor-mediated PMN degranulation and phagocytosis. Synovial fluid samples from 11 RA patients were studied; 10 of them contained factor(s) which augmented phagocytosis and degranulation mediated through the Fc receptor. This factor(s) alone, however, did not initiate neutrophil degranulation: its MW is less than 10,000 daltons and it is unstable when heated to 56 degrees C. We also examined supernatants that were produced by coculturing adherent human mononuclear cells stimulated by IgG-coated sheep red blood cells with autologous nonadherent mononuclear cells. A factor(s) with properties similar to those found in the synovial fluids (i.e., heat-labile at 56 degrees C and capable of augmenting Fc receptor-mediated degranulation and phagocytosis) was found in the stimulated human mononuclear cell culture supernatants. Filtration studies indicated that the MW of this factor(s) is between 2,000 and 10,000 daltons. No such activity was detected in culture supernatants of unstimulated mononuclear cells. Production of the cytokine was blocked by cycloheximide, indicating that protein synthesis was necessary. This factor(s), by enhancing PMN degranulation, may augment PMN-mediated tissue destruction in diseases such as RA.
Adult↗
Alterations in macrophage collagenase secretion induced by gold sodium thiomalate.
The effects of gold sodium thiomalate (GST) on the production of specific collagenase by thioglycolate-elicited macrophages was investigated. Our studies demonstrated that GST administration can significantly decrease collagenase production in a dose-dependent manner. These effects were observed with levels of GST attainable in serum or synovial tissue during routine chrysotherapy. In addition, GST altered lysozyme secretion by activated macrophages in a pattern distinct from that of collagenase alteration. These effects of enzyme secretion were not secondary effects of GST on viability, general protein secretion, or the specific assay procedures utilized, and were not attributable to the thiomalate moiety. Thus, GST may exert its therapeutic effect in rheumatoid arthritis through interference with the production of degradative proteolytic enzymes, which are important effector molecules mediating tissue destruction.
Animals↗
Isolation, characterization, and amino-terminal amino acid sequence analysis of human neutrophil cathepsin G from normal donors.
Human neutrophil cathepsin G from normal donors has been purified 82-fold using an isolation procedure which included sequential sodium chloride extraction, Aprotonin-Sepharose affinity chromatography, CM-cellulose ion-exchange chromatography, and AcA44 gel filtration chromatography. The inclusion of this last purification step was crucial for separating inactive lower molecular weight species from the active forms of neutrophil cathepsin G and resulted in a higher specific activity of the final preparation. SDS polyacrylamide gradient gel electrophoresis of the purified reduced protein demonstrated three discrete polypeptides of Mr 31,000, 30,000, and 29,500. Peptide analysis of tryptic digests indicated that these three polypeptides are structurally related to each other and represent microheterogeneity of the purified protein. The cathepsin G peptide maps were distinctly different from the peptide maps of neutrophil elastase. The apparent isoelectric points of these forms as determined by two-dimensional electrophoresis was approximately 8.0. Utilizing microsequencing techniques, the first 25 residues of normal neutrophil cathepsin G have been determined and shown to be identical (except for residue 11) with the sequence of 21 residues of cathepsin G isolated from leukemic myeloid cells. A high degree of homology was found when the amino-terminal regions of neutrophil cathepsin G, rat mast cell protease II (65%) and two human serine proteinases, factor D (52%) and neutrophil elastase (48%), were compared. A precipitating monospecific antiserum to cathepsin G was produced by repeated immunizations of guinea pigs. This antiserum has been used in immunoblotting experiments to demonstrate that the intracellular form(s) of this enzyme is the same approximate Mr as the purified enzyme, and to develop a solid-phase radioimmunoassay for measuring neutrophil cathepsin G in the range 5-50 ng/ml.
Amino Acid Sequence↗
Induction of neutrophil enzyme release by rheumatoid factors: evidence for differences based on molecular characteristics.
Cathepsin G and elastase are two neutrophil proteases capable of degrading the major structural macromolecules of the joint. Evaluation of factors capable of inducing the release of these enzymes is crucial to the understanding of neutrophil-mediated tissue destruction. We have evaluated the effects of IgM rheumatoid factor (RF), as well as monomeric and polymeric forms of IgA RF, on the release of neutrophil elastase, cathepsin G, and the specific granule protein lactoferrin. None of these rheumatoid factors alone was able to induce more lysosomal protein release than media controls. Under conditions used in this study, aggregated human IgG was able to induce slightly more release than media controls. The addition of IgM RF or polymeric IgA RF to the aggregated IgG resulted in release of significantly more lysosomal proteins than aggregates alone. In contrast, monomeric IgA RF, even in the presence of aggregated IgG, was unable to augment enzyme release. These results suggest that differences in the molecular characteristics of RF found in synovial fluid may significantly influence the contribution of RF to tissue injury in rheumatoid arthritis.
Arthritis, Rheumatoid↗
Specific cleavage of human type III and IV collagens by Pseudomonas aeruginosa elastase.
Purified Pseudomonas aeruginosa elastase cleaved human type III and IV collagens with the formation of specific cleavage products. Furthermore, type I collagen appeared to be slowly cleaved by both P. aeruginosa elastase and alkaline protease. These cleavage fragments from type III and IV collagens were separated from the intact collagen chains by SDS polyacrylamide gradient gel electrophoresis run under reducing conditions, and they were detected by their characteristic Coomassie blue staining pattern. The results of these studies suggest that the pathogenesis of tissue invasion and hemorrhagic tissue necrosis observed in P. aeruginosa infections may be related to the degradation of these collagen types by bacterial extracellular proteases.
Collagen↗
Degradation of soluble laminin and depletion of tissue-associated basement membrane laminin by Pseudomonas aeruginosa elastase and alkaline protease.
Purified Pseudomonas aeruginosa elastase and alkaline protease rapidly cleaved soluble laminin, with each enzyme yielding different cleavage products. These cleavage fragments were separated from the intact laminin A and B polypeptide chains by sodium dodecyl sulfate-polyacrylamide gradient gel electrophoresis and detected by their characteristic Coomassie blue staining patterns. Pseudomonas elastase produced rapid and extensive degradation of both A and B chains, including the disulfide-rich regions. Apparently complete degradation to limit digests was obtained after 30 min with a substrate/enzyme ratio of 30:0.5. Under similar conditions, alkaline protease rapidly degraded the A chain while slowly degrading the B chain. In addition, immunoreactive laminin was released from authentic basement membranes after incubation with either enzyme as detected by an enzyme-linked immunoabsorption assay and by immunofluorescence. The results from these studies suggest a direct role for elastase and alkaline protease in both tissue invasion and hemorrhagic tissue necrosis in P. aeruginosa infections.
Animals↗
Rheumatoid arthritis associated with expanded populations of granular lymphocytes.
Two patients with classic rheumatoid arthritis developed severe neutropenia and increased numbers of large granular lymphocytes in the blood and bone marrow. These lymphocytes exhibited homogeneous surface membrane immunophenotypes of Leu5+, Leu11-, Leu4+, Leu3-, Leu2-, Leu7+ and Leu5+, Leu11+, Leu4+, Leu3-, Leu2+, Leu7-, respectively. In both patients, neutropenia was initially corrected with corticosteroid therapy; long-term improvement followed low-dose oral cyclophosphamide and methotrexate therapies. In these 2 patients and 12 previous patients with rheumatoid arthritis associated with expanded populations of immunophenotypically homogeneous large granular lymphocytes, neutropenia occurred in all 14, thrombocytopenia in 6, anemia in 7, and mild or moderate splenomegaly in 12. In contrast to Felty's syndrome, granular lymphocyte expansions in rheumatoid arthritis usually occur in older patients, may appear simultaneously with arthritis, and are usually associated with normal or elevated blood leukocyte counts. Mild hemocytopenias in these patients can often be managed with observation. Therapy with corticosteroids or immunosuppressive-cytotoxic drugs may be beneficial in more severe cases, but splenectomy is not recommended.
Aged↗
Isolation, characterization, and amino-terminal amino acid sequence analysis of human neutrophil elastase from normal donors.
Human neutrophil elastase from normal donors has been purified using an isolation procedure which included sequential sodium chloride extraction, Aprotinin-Sepharose affinity chromatography, CM-cellulose ion-exchange chromatography, and AcA44 gel filtration chromatography. The inclusion of this last purification step was crucial for separating inactive lower molecular weight species from the active forms of neutrophil elastase and resulted in a higher specific activity of the final preparation. Sodium dodecyl sulfate-polyacrylamide gradient gel electrophoresis of the reduced purified protein demonstrated three polypeptides of Mr 31,000, 28,000, and 27,500. Four polypeptides were resolved on acid gel electrophoresis; each of the four possessed amidolytic activity. Furthermore, peptide analysis of Staphylococcus aureus V8 protease digests indicated that these polypeptides are structurally related to each other and represent microheterogeneity of the purified protein. The apparent isoelectric points of these four forms as determined by two-dimensional electrophoresis range from 6.1 to 6.7. By utilizing microsequencing techniques, the first 40 residues of neutrophil elastase have been determined and compared with the reported sequence of elastase isolated from leukemic myeloid cells. In addition, a high degree of homology was found within the amino-terminal regions of neutrophil elastase and the serine proteinases porcine elastase, bovine chymotrypsin, human factor D, and the beta chain of plasmin.
Amino Acid Sequence↗
Pure red cell aplasia and protein-losing enteropathy in a patient with systemic lupus erythematosus.
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Adult↗
Solid-phase radioimmunoassay for human neutrophil elastase: a sensitive method for determining secreted and cell-associated enzyme.
A solid-phase radioimmunoassay for measuring neutrophil elastase in the range 0.08-4 ng/ml has been developed. A monospecific, precipitating antibody capable of inhibiting elastinolysis was produced by repeated immunizations of a goat. The IgG fraction and affinity-purified antibodies of this serum were then obtained and used to develop this radioimmunoassay. There was no cross-reactivity in binding of the radiolabeled antisera with lactoferrin, cathepsin G, or serine proteinases with amino-terminal amino acid sequence homology. Although serum influences the measurement of catalytically active neutrophil elastase when compared to diisopropylfluorophosphate-treated neutrophil elastase, antigenic elastase may still be measured in body fluids. Furthermore, this assay is more sensitive than commercially available substrates used for quantitating neutrophil elastase by functional activity. We have found this quantitative assay extremely useful in balance studies to measure secreted and cell-associated elastase and in screening of biological fluids for the presence of the enzyme.
Animals↗
Purified human mast cells and basophils release human elastase and cathepsin G by an IgE-mediated mechanism.
Human lung mast cells and human peripheral basophils were purified and examined for their content of proteolytic enzymes similar to lung Hageman factor activator (LHFA) previously found to be released from chopped human lung by an IgE-mediated mechanism. It was found that both cell types contained elastase and cathepsin G-like enzymes, and that elastase appeared to be responsible for LHFA activity. The enzymes, as well as histamine, were released in a dose-dependent manner from these cells by anti-IgE antibody and by ionophore A 23187. It appears that stimulation by either anti-IgE or ionophore increases the amount of both enzymes extractable from these cells. The release of these proteases may explain some of the inflammation and observed defects in coagulation which occur as a result of anaphylaxis.
Basophils↗
Local synthesis of IgM and IgM rheumatoid factor in rheumatoid pleuritis.
Pleura from 3 patients with rheumatoid pleuritis and from 5 patients with other diseases was examined for its capacity to synthesize IgM and IgM rheumatoid factor (RF). IgM was synthesized by pleura from all 3 patients with rheumatoid pleuritis and IgM RF by 2. Pleura from each of the control patients synthesized less than or equal to 1 ng/mg of IgM and IgM RF. Moreover, pleura from a 4th patient with rheumatoid pleuritis incorporated 3H-leucine into newly synthesized IgM. Simultaneously obtained pleural fluid mononuclear cells (MNL) and pleural tissue from a patient with rheumatoid pleuritis synthesized identical proportions of IgM and IgM RF whereas IgM RF production was not observed with peripheral blood MNL from the same patient. The results support the view that local production of IgM and IgM RF occurs in rheumatoid pleuritis and suggest that local immune events contribute to the pathogenesis of this disorder.
Arthritis, Rheumatoid↗
The diagnosis of rheumatoid arthritis.
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Arthritis, Rheumatoid↗
Medical pathology conference fever of undetermined origin with abnormal chest X-ray and accelerated ESR.
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Bronchi↗
DFP-sensitive polypeptides of the guinea pig peritoneal macrophage.
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Alkylation↗
Systemic capillary leak syndrome and monoclonal IgG gammopathy; studies in a sixth patient and a review of the literature.
The clincical and laboratory features of a sixth patient with periodic systemic capillary leak syndrome are reported. During an attack metabolic studies demonstrated a marked shift of plasma (10 to 70%) from the intravascular to the extravascular space resulting in hemoconcentration (highest hematocrit of 82). At the termination of the attack there was a return of the electrolytes, water and proteins to the intravascular compartment. The cardiovascular, renal and endocrine compensation was appropriate to this insult and no underlying abnormalities were demonstrated in these systems. The effector pathways of coagulation, complement, bradykinin generation, prostaglandins and histamine metabolism did not appear to be responsible for the altered capillary permeability. The patient was not missing inhibitors of these same pathways. The only persistently abnormal finding was a monoclonal IgG gammopathy. However, further studies of this paraprotein did not uncover a link between it and the abnormal capillary permeability. Five similar cases are reviewed; at least four and possibly all of these patients also had an IgG paraprotein. Treatment of these attacks was unsuccessful. Attemps to prevent the episodes with a wide variety of therapeutic agents failed. Treatment of the acute attacks with administration of intravenous fluids, did not maintain an adequate intravascular volume and may lead to fluid overload upon return of normal capillary integrity. Pressor agents were of no apparent value and may cause increased cardiac irritability. Although the clinical features and pathophysiology of the capillary leak syndrome have been defined, the etiology remains unknown.
Adult↗