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K J Johnson

Publications and source records attributed to K J Johnson.

At least 181 records · Page 10Linked to original sources
PubMed1985

Evaluation of an ELISA system for determination of class-specific antibodies to native and denatured DNA in man.

Enzyme-linked immunosorbent assays (ELISA) have been set up for determination of plasma IgG and IgM antibodies to native (n) and denatured (d) DNA. Normal male and female donors generally gave low values in the assays for IgG; IgM control values were higher, particularly in females. Mean values for patients with systemic lupus erythematosus (SLE) were greatly raised in all four categories of assay in relation to the control (female) group. Levels of IgG anti-nDNA in SLE correlated well with a standard diagnostic test (Farr), and this ELISA assay was more successful than Farr in discriminating between patients and normal females. No such correlation with Farr was found for IgM anti-nDNA. Correlations were found in SLE between levels of antibodies to nDNA and dDNA. Inhibition tests--including those with a plasmid DNA preparation containing no single-stranded regions--showed that most of the IgG antibodies determined in the 'native' assay were able to bind to nDNA and dDNA with comparable avidity, whereas most of those reacting in the 'denatured' assay could only bind dDNA. The former antibodies were probably directed against shared determinants on the deoxyribose-phosphate backbone and the latter against base-dependent structures not exposed in nDNA. Inhibition results for IgM assays were similar, though the predominance of antibodies specific for dDNA appeared less marked. ELISA assays could well prove more useful than established methods in diagnosis and monitoring of SLE and other diseases.

Antibodies↗
PubMed1985

Activated rat neutrophils. Correlation of arachidonate products with enzyme secretion but not with O(2)- generation.

Functional responses (enzyme secretion and generation of O2-) have been studied in rat neutrophils with the use of a variety of different agonists which vary in their ability to activate neutrophils. Concomitantly, the authors have analyzed the cells for production of cyclooxygenase (PGE2, PGF2 alpha, and TXB2) and lipoxygenase (monoHETEs and LTB4) products in order to determine whether there is a correlation between functional responses and arachidonate products in stimulated neutrophils. The studies indicate that enzyme secretion is closely correlated with generation of arachidonate (cyclooxygenase as well as lipoxygenase) products. These responses are dependent on the dose of agonist employed, but there does not appear to be a unique pattern of arachidonate products that can be attributed to a specific agonist. With respect to monohydroxyeicosatetraenoic acid (monoHETE) generation, we demonstrate that stimulated rat neutrophils selectively produce 5-HETE, to the virtual exclusion of 12-HETE and 15-HETE. The production of O2- from stimulated rat neutrophils is correlated neither with enzyme secretion nor with the generation of arachidonate products. These studies suggest that enzyme secretion and O2- generation are mediated by two fundamentally different intracellular pathways, even though these functional responses probably derive from common agonist-receptor interactions on the plasma membrane.

Animals↗
PubMed1984

Mesangial proliferative glomerulonephritis with IgM deposits. Clinicopathologic analysis and evidence for morphologic transitions.

To determine the natural history of mesangial proliferative glomerulonephritis (MesPGN) with IgM deposits and its relationship to minimal change disease (MC) and focal segmental glomerulosclerosis (FGS), we studied the clinical characteristics and outcome in 20 patients with MesPGN, 8 with MC, and 10 with FGS. IgM deposits were present in glomeruli of all MesPGN patients. Progression to FGS was documented in 2 patients with MesPGN, 1 of whom developed renal failure. Transition from MC to MesPGN occurred in 1 patient. 2 MC patients developed FGS, with decline in renal function in 1 of them. These data suggest the possibility of histologic transition from MC to FGS directly or through the stage of MesPGN.

Adolescent↗
PubMed1984

Acute lung injury in rat caused by immunoglobulin A immune complexes.

Mouse IgG and IgA, with reactivity to dinitrophenol conjugated to carrier protein, have been isolated from myeloma proteins by means of a variety of affinity techniques. The IgA was predominantly in the dimeric form. The in vitro and in vivo biological activities of IgA-containing immune complexes were assessed in the rat. IgA-containing immune complexes were demonstrated, in a dose-dependent manner in vitro, to activate neutrophils and to generate O.-2. In addition, these immune complexes showed evidence of complement activation in vitro, by the use of immunofixation techniques. When IgA was instilled into the airways of rats and antigen was injected intravenously, acute lung injury occurred, as reflected by increases in lung permeability and morphological changes consisting of blebbing of endothelial cells, intra-alveolar hemorrhage, and fibrin deposition. The lung changes were directly proportional to the amount of IgA instilled into the airways and failed to occur if intravenous injection of antigen was omitted. Lung injury did not occur in animals that received an intravenous injection of antigen in the absence of an airway injection of IgA. Lung injury related to IgA-containing immune complexes was complement dependent but neutrophil independent. In companion studies with mouse IgG-containing immune complexes, acute lung injury also occurred and had morphological features similar to those associated with IgA-induced lung injury except that, in the case of IgG immune complex-induced damage, neutrophils were more evident. Acute lung injury induced by IgG-containing immune complexes, whether of mouse or rabbit origin, was complement and neutrophil dependent. The similarities and differences between IgG- and IgA-associated acute immune complex-induced injury of rat lung were reinforced by the use of morphometry techniques. Studies with another monoclonal IgA antibody-containing antigen-binding activity to phosphorylcholine also demonstrated the ability of IgA antibody to cause acute lung injury in the rat. Neither antibody alone nor antigen (phosphorylcholine linked to bovine serum albumin) alone produced evidence of lung injury. These studies indicate for the first time that immune complexes containing IgA have lung-damaging properties and that the pathogenic mechanisms are different from those associated with IgG-associated immune complex-induced acute lung injury.

Animals↗
PubMed1984

Rat neutrophil activation and effects of lipoxygenase and cyclooxygenase inhibitors.

Activation (defined as lysosomal enzyme secretion and generation of O(2) of rat neutrophils has been measured with the use of varying doses of soluble stimuli (phorbol myristate acetate (PMA); calcium ionophore A23187; and N-formyl-methionyl-leucyl-phenyl-alanine (FMLP] and particulate agents (immune complexes and zymosan particles). With either the calcium ionophore or the chemotactic peptide (FMLP), substantial enzyme release occurred, but the amount of O(2) produced was very small. Cytochalasin B greatly enhanced the enzyme release response to the chemotactic peptide but had little effect on neutrophil responses to other soluble stimuli. The cell response to PMA resulted in the greatest production of O(2) with significant enzyme secretion. When cell stimulation with insoluble stimuli (immune complexes or zymosan particles) was studied, significant amounts of enzyme release occurred in parallel with the generation of substantial amounts of O(2). The presence of cytochalasin B enhanced the cell responses to immune complexes but had an inhibitory effect on zymosan-induced responses. As expected, the amount of lysozyme secreted by stimulated rat neutrophils tended to exceed the amount of beta-glucuronidase released from the same cells. Neutrophil responses were investigated in the presence of drugs that were demonstrated in the rat neutrophil to inhibit either the lipoxygenase or the cyclooxygenase pathway. Inhibitors of the cyclooxygenase pathway (indomethacin, piroxicam, ibuprofen, BW755C), with few exceptions, consistently enhanced the enzyme secretion response, while effects on O(2) generation were less clear-cut but tended to be predominantly inhibitory. Drugs with inhibitory effects on the lipoxygenase pathway (nordihydroguaiaretic acid and nafazatrom) had significant inhibitory effects on both enzyme secretion as well as generation of O(2). These data suggest that activation responses (enzyme secretion and O(2) generation) of rat neutrophils may be dissociated (ie, one not always accompanying the other). Further, it appears that neutrophil activation, as defined by enzyme secretion, is enhanced by products of the lipoxygenase pathway and suppressed by products of the cyclooxygenase pathway. Generation of O(2) is not affected in such a clear-cut manner. Taken together the data suggest that enzyme release and O(2) production by activated rat neutrophils may be under separate control.

4,5-Dihydro-1-(3-(trifluoromethyl)phenyl)-1H-pyraz↗
PubMed1984

Evidence for the role of oxygen radicals in acute nephrotoxic nephritis.

Acute glomerular injury in the rat has been induced by the intrarenal, intraarterial infusion of sheep antibody to glomerular basement membrane (antiglomerular basement membrane). The antiglomerular basement membrane antibody has been verified to be of the variety that is complement and neutrophil dependent for the induction of acute proteinuria, which peaks during the first 24 hours. Following injection of the antibody, acute, intense, glomerular injury resulted, with the denuding of glomerular vascular basement membrane associated with extensive damage or destruction of glomerular endothelial cells and fusion of epithelial cell foot processes. Treatment of animals with catalase produced, in a dose-dependent manner, as much as 75% protection against glomerular injury, as assessed by reduction in the proteinuria. Treatment of animals with superoxide dismutase caused a small reduction in the degree of glomerular injury, again assessed by a reduction in proteinuria. However, this protective effect of superoxide dismutase was not found to be statistically significant. The hydroxyl radical scavenger, dimethyl sulfoxide, which has been shown to protect against endothelial cell injury following systemic activation of complement, was not protective in the anti-GBM model. Morphologically, glomeruli from catalase-protected rats showed numerous neutrophils but little or no evidence of injury of either glomerular endothelial or epithelial cells. These data suggest that acute glomerular injury produced by antiglomerular basement membrane is related to H2O2 production from activated neutrophils.

Acute Disease↗
PubMed1984

Evidence for a role of hydroxyl radical in immune-complex-induced vasculitis.

Previously it was shown that tissue injury occurring in acute immune-complex-induced vasculitis, which is complement and neutrophil-dependent, is significantly attenuated by the presence of catalase, suggesting the pathogenic role of H2O2 generated from activated neutrophils. We now show that significant protection is also afforded by pretreatment of animals with apolactoferrin , a naturally occurring chelator of iron. Iron-saturated lactoferrin is devoid of protective effects. Deferoxamine mesylate, a synthetic iron chelator, also has protective effects. Infusion of ionic iron, especially Fe(III), potentiates the tissue injury. Significant protection from tissue injury is also produced by treatment of rats with dimethyl sulfoxide, a potent hydroxyl radical scavenger. Morphologically, animals treated with these protective interventions show the influx of neutrophils into sites of immune complex deposition, but there is markedly attenuated edema, little or no hemorrhage, and little evidence of endothelial cell injury, in contrast to the findings in nonprotected animals. These data support the suggestion that immune-complex-induced injury may be linked to generation of H2O2 from activated neutrophils and the subsequent conversion of H2O2 to the hydroxyl radical.

Animals↗
PubMed1984

ADP-ribosylation and post-irradiation cellular recovery in two strains of L5178Y cells.

Two strains of murine lymphoma cells, L5178Y-R (LY-R) and L5178Y-S (LY-S) differ in radiosensitivity (D0 ca 1.0 and 0.5 Gy) In this cellular system we tested the influence of poly (adenosine diphosphoribose) transferase (ADPRT) inhibitors, benzamide and caffeine, in combination with X or gamma irradiation under aerobic conditions, on the cellular response. We found a small difference between LY-R and LY-S cell strains in incorporation of 3H from [3H]-NAD (nicotinamide dinucleotide) into permeabilized cells. The incorporation was related to DNA degradation initiated by the permeabilization procedure. The post-irradiation inhibition of DNA synthesis was reversed only in LY-S cells by 2mM benzamide or 2mM caffeine treatment. Changes in the cell cycle, as determined by flow-cytometry, were of similar character in both LY-R and LY-S cells, within 12 h after irradiation, whereas the effect of treatment on survival differed: only LY-S cells were radiosensitized by benzamide; both LY strains were sensitized by caffeine, but to different extents. From these observations it followed that there was a pattern of relations between the extent of postirradiation DNA synthesis, duration of mitotic delay and recovery.

Adenosine Diphosphate Ribose↗
PubMed1984

Protein degradation following treatment with hydrogen peroxide.

Pretreatment of hemoglobin with 50-5000 nmol hydrogen peroxide (H2O2) increased its susceptibility to proteolysis by a number of purified enzymes, including trypsin, chymotrypsin, elastase, and plasmin, and by the neutral protease of rat peritoneal leukocytes. Pretreatment of the protein substrate with catalase-inactivated H2O2 had no effect. Separation of the proteolytic fragments by G-75 Sephadex gel filtration indicated no apparent differences in the size distribution of the fragments produced by treatment with the H2O2/proteolytic enzyme combination as compared with enzyme treatment alone. A partially purified preparation of rat glomerular basement membrane was also treated with proteolytic enzyme alone or in combination with H2O2. As with the hemoglobin, pretreatment of the glomerular basement membrane with H2O2 increased its susceptibility to subsequent proteolytic attack. In addition, treatment of a basement membrane glycoprotein, fibronectin, with H2O2 also increased its sensitivity to subsequent proteolysis. These results suggest that in addition to their other proinflammatory activities, oxygen-derived metabolites may contribute to tissue destruction by altering the susceptibility of proteins to hydrolytic enzymes.

Animals↗
PubMed1983

Oxygen radical dependent lung damage following thermal injury of rat skin.

Acute thermal injury (70 degrees C, 30 sec) to rat skin results in progressive consumptive depletion of the complement system. Individual complement components (C3, C4, C6) each show reductions in hemolytic activity. Crossed immunoelectrophoresis analysis of serum from thermally injured rats reveals conversion of C3 compatible with activation of the complement system. During the first hour following thermal injury, C5a-related chemotactic activity appears in the serum and is temporally related to the development of neutropenia. Lung injury, as revealed by increases in lung permeability, develops progressively during a 6-hour period and parallels changes in complement levels. Morphologically, lung changes include leukoaggregates within pulmonary capillaries and the presence of intra-alveolar hemorrhage. Protection from lung injury following remote thermal injury to skin is afforded by depleting animals of complement or neutrophils, or by systemic treatment of animals with a combination of catalase and superoxide dismutase. Antihistamine drugs have no protective effect. These data suggest that acute thermal injury leads to systemic complement activation, neutrophil activation, and acute lung injury that is related to production of toxic oxygen products by activated blood neutrophils.

Animals↗
PubMed1983

In vitro and in vivo stimulation of rat neutrophils and alveolar macrophages by immune complexes. Production of O-2 and H2O2.

Rat neutrophils and alveolar macrophages were quantitatively studied for production of O-2 and H2O2 after incubation of cells with immune complexes, and the responses were compared with those produced after cell contact with phorbal myristate acetate or zymosan particles. The production of toxic oxygen products is a linear function of cell number, the duration of incubation, and the amount of immune complex employed. In the case of neutrophils, there is a direct relationship between the amounts of immune complex internalized, secretory release of lysosomal enzymes, and production of O-2 and H2O2. With both neutrophils as well as alveolar macrophages, maximal production of O-2 occurs with the largest complexes (formed under conditions of antigen equivalence). When limiting cell concentrations are used, alveolar macrophages produce considerably more oxygen products than an equivalent number of peritoneal neutrophils obtained from the same animals. Thus, alveolar macrophages as well as neutrophils represent important potential sources for the generation of toxic oxygen products in lung inflammatory reactions. Experiments have also been designed to estimate the relative contributions of neutrophils and alveolar macrophages in vivo during acute immune complex deposition in lung. The data indicate that both neutrophils and alveolar macrophages are activated by in vivo exposure to immune complexes, each cell type producing a 2-4-fold increase (over baseline levels) in the amounts of O-2. Thus, alveolar macrophages as well as neutrophils may play an important role in the generation of toxic oxygen products that have been incriminated in the pathogenesis of acute lung injury following deposition of immune complexes.

Acetylglucosaminidase↗
PubMed1982

Nonspecific protease and elastase activities in rat leukocytes.

Extracts were prepared from rat peritoneal leukocytes obtained 4 h after glycogen injection and assayed for proteolytic enzyme activities against various substrates. The substrates used included acid-denatured bovine hemoglobin, bovine serum albumin, a partially purified preparation of rat pulmonary basement membrane, bovine neck ligament elastin, and an artificial substrate with elastase specificity. A high level of activity was observed when hemoglobin was used as the substrate. The serum albumin and basement membrane preparation were also readily hydrolyzed by the leukocyte extract. In contrast, the native elastin and synthetic elastase substrate were much more resistant. Although the leukocyte extract demonstrated little intrinsic elastase activity, when it was mixed with a commercial hog pancreatic elastase preparation, it greatly potentiated the elastolytic activity, suggesting the activation of a latent enzyme.

Animals↗
PubMed1982

Intravascular activation of complement and acute lung injury. Dependency on neutrophils and toxic oxygen metabolites.

Intravascular activation of the complement system with cobra venom factor results in acute lung injury, which has been quantitated by increases in lung vascular permeability. Cobra venom factor preparations devoid of phospholipase A2 activity retain full lung-damaging capacity. The lung injury is associated with the preceding appearance of chemotactic activity in the serum coincident with the development of a profound neutropenia. The chemotactic activity is immunochemically related to human C5a. Morphologic studies have revealed discontinuities in the endothelial cell lining of lung alveolar capillaries, damage and/or destruction of endothelial cells in these areas, plugging of pulmonary capillaries with neutrophils that are in direct contact with vascular basement membrane, the presence of fibrin in alveolar spaces and in areas adjacent to damaged endothelial cells, and intraalveolar hemorrhage. Lung injury is dramatically attenuated in animals that have been previously neutrophil depleted. Teh intravenous injection of superoxide dismutase or catalase also provides significant protection from the pulmonary damage. Very little protection from the pulmonary damage. Very little protection is afforded by pretreatment of rats with antihistamine. These studies suggest that intravascular activation of the complement system leads to neutrophil aggregation and activation, intrapulmonary capillary sequestration of neutrophils, and vascular injury, which may be related to production of toxic oxygen metabolites by complement-activated neutrophils.

Animals↗