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D M Center

Publications and source records attributed to D M Center.

At least 91 records · Page 5Linked to original sources
PubMed1984

Identification and characterization of neutrophil chemotactic activity in aspirin-induced asthma.

In order to determine if mast cell mediators are released during aspirin challenge in aspirin-sensitive asthmatics, we measured neutrophil chemotactic activity, which has been shown to be an indicator of mast cell degranulation. Four aspirin-sensitive asthmatic subjects were given doses of aspirin (60 to 325 mg) previously determined to cause a 20 to 30% fall in forced expiratory volume in one second (FEV1); pulmonary function was followed by serial spirograms and body plethysmography. Serum was obtained before and at 30, 60, 90, 120, 180, and 240 min after challenge, corresponding to the times of pulmonary function measurements. Neutrophil chemotactic activity was measured using a modified Boyden chamber assay. Maximal bronchoconstriction occurred 60 to 120 min after aspirin ingestion. An increase in neutrophil chemotactic activity of 300 to 600% over baseline was detected in all subjects. In 3 subjects, neutrophil chemotactic activity release paralleled bronchoconstriction, and in 1 subject, it followed onset of bronchoconstriction. Physicochemical analysis showed that the neutrophil chemotactic activity eluted in the void volume of a Sephadex G-200 column (greater than or equal to 250,000 daltons) and from Sephadex QAE anion exchange chromatography in a region corresponding to 0.2 to 0.3 M NaCl. Its isoelectric point was in the pH range 6.5 to 7.5. These characteristics are compatible with neutrophil chemotactic factor of mast cell origin. Pretreatment with sodium cromolyn (40 mg) completely eliminated neutrophil chemotactic factor release, but only partially suppressed the fall in FEV1 in 2 subjects and had no effect on FEV1 fall in a third.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Influence of ethanol on human T-lymphocyte migration.

Because ethanol consumption is associated with increased susceptibility to infection, we examined the effects of ethanol and its metabolite acetaldehyde on human T-lymphocyte migration, an important functional component of cellular inflammatory responses. With a modified Boyden chamber system, ethanol at 0.25% and 0.50% (vol/vol) inhibited spontaneous motility of human T-lymphocytes, in a noncytotoxic manner, to 65% +/- 7% (mean +/- SEM) and 62% +/- 7% of control values of migration, respectively. When T-lymphocyte migration was stimulated by colchicine (10(-5) mol/L), incubation with ethanol (0.25% and 0.50%, vol/vol) decreased migration to 80% +/- 4% and 66% +/- 8% of control values, respectively. Similar degrees of inhibition of migration were obtained with acetaldehyde at concentrations five to 10 times less than ethanol. Ethanol was similarly capable of inhibiting T cell migration induced by dibutyryl cyclic guanosine monophosphate, but it had no effect on stimulated migration induced by a human chemokinetic lymphokine. Our study demonstrates that ethanol, at concentrations achievable in vivo, is capable of depressing T-lymphocyte migration. This effect might contribute to the immunosuppression associated with ethanol consumption.

Acetaldehyde↗
PubMed1984

Functional characteristics of histamine receptor-bearing mononuclear cells. II. Identification and characterization of two histamine-induced human lymphokines that inhibit lymphocyte migration.

Although functional histamine receptors have generally been restricted to those human T lymphocytes expressing suppressor cell functions, more recent evidence suggests that histamine receptor-bearing human T lymphocytes are functionally heterogeneous and capable of other immunomodulatory activities. Lymphocyte chemoattractant factor (LCF) is a cationic sialoprotein with an apparent m.w. of 56,000, whose production is limited to histamine-type 2 receptor-bearing human T cells. LCF is selectively chemokinetic for T lymphocytes, and presumably contributes to the recruitment of unsensitized effector lymphocytes at inflammatory sites. In addition to LCF, Sephadex G-100 gel filtration of histamine-induced lymphocyte supernatants revealed two regions of migration inhibitory activity for human blood T and rat splenic lymphocytes. These regions corresponded to m.w. of 70,000 to 80,000 (LyMIF75K) and 30,000 to 40,000 (LyMIF35K). LyMIF75K had a single pI of 7.5 to 8.0, and its biologic activity was sensitive to trypsin but not to neuraminidase or heat (56 degrees C). LyMIF35K had a single pI of 8.5 to 8.8, and its biologic activity was sensitive to neuraminidase and heat but not to trypsin. These LyMIFs therefore appeared to be distinct from one another and physicochemically different from other migration inhibitory lymphokines. All three lymphokine activities appeared within 4 hr of incubation. The minimum concentration of histamine required to stimulate production of the LyMIF was 10(-6) M. Lymphocytes that did not adhere to a histamine affinity matrix were unable to produce either LyMIF upon subsequent stimulation with histamine or concanavalin A (Con A). Lymphocytes incubated with histamine and diphenhydramine produced LCF but neither LyMIF, whereas cells incubated with histamine in the presence of cimetidine produced both LyMIF but not LCF. These data suggest that a subset of lymphocytes defined by the presence of histamine-type 1 receptors are capable of producing two distinct species of lymphocyte migration inhibitory activity. These cells may contribute to the immobilization of effector T lymphocytes chemokinetically attracted to certain inflammatory sites.

Adult↗
PubMed1983

Identification of rat mast cell--derived chemoattractant factors for lymphocytes.

Rat peritoneal and pleural mast cells have been demonstrated to release their granule-associated mediators, including chemotactic factors for eosinophilic polymorphonuclear leukocytes, after challenge with rabbit anti-rat F(ab')2 antisera in vitro. The presence of increased numbers of lymphocytes as well as eosinophils 6 to 24 hr after an initial immediate hypersensitivity reaction in the skin led to the present studies, which demonstrate the immunologic release of three chemoattractant factors for lymphocytes. One factor is chemotactic for nylon wool nonadherent rat splenic lymphocytes, a second factor is chemotactic for adherent rat splenic lymphocytes, and the third factor is chemokinetic for both nonadherent and adherent rat splenic lymphocytes. In addition, a high-molecular-weight inhibitor of lymphocyte migration was identified. Immunologic challenge of rat mast cells in vitro results in the release of lymphotactic activity, suggesting a possible explanation for the appearance of a lymphocytic infiltrate in the late phase of the immediate hypersensitivity reaction.

Animals↗
PubMed1983

Nitrogen Turnover and Assimilation during Regrowth in Trifolium subterraneum L. and Bromus mollis L.

Subterranean clover (Trifolium subterraneum L. cv Woogenellup) and soft chess grass (Bromus mollis L. cv Blando) were grown in monocultures with (15)NH(4)Cl added to the soil to study nitrogen movement during regrowth following shoot removal. Four clipping treatments were imposed. Essentially all available (15)N was assimilated from the soil prior to the first shoot harvest. Measurements of total reduced nitrogen and (15)N contained within that nitrogen fraction in roots, crowns, and shoots at each harvest showed large, significant (P </= 0.001) declines in excess (15)N of crowns and roots in both species between the first and fourth harvests. There was no significant decline in total reduced nitrogen in the same organs over that period. Similar responses were evident in plants defoliated three times. The simplest interpretation of these data is that reduced nitrogen compounds turn over in plant roots and crowns during shoot regrowth. Calculations for grass and clover plants clipped four times during the growing season indicated that 100 to 143% of the nitrogen present in crowns and roots turned over between the first and fourth shoot harvest in both species, assuming nitrogen in those organs was replaced with nitrogen containing the lowest available concentration of (15)N. If other potential sources of nitrogen were used for the calculations, it was necessary to postulate that larger amounts of total nitrogen flowed through the crown and root to produce the measured dilution of (15)N compounds. These data provide the first quantitative estimates of the amount of internal nitrogen used by plants, in addition to soil nitrogen or N(2), to regenerate shoots after defoliation.

Journal Article↗
PubMed1983

Identification of chemoattractant activity for lymphocytes in blister fluid of patients with bullous pemphigoid: evidence for the presence of a lymphokine.

Bullous pemphigoid is characterized by the dermal infiltration of lymphocytes, which precedes the striking influx of eosinophils as the lesion evolves into the bullous phase. This finding prompted a search for chemoattractant activity for lymphocytes in the blister fluid of untreated individuals with bullous pemphigoid. We found such activity in the bullous fluids of 6 consecutive patients but not in a patient with pemphigus vulgaris. This lymphocyte chemoattractant activity separates into 4 peaks upon Sephadex G-100 chromatography and the peak of 56,000 daltons was further evaluated. Upon quaternary aminoethyl Sephadex-anion exchange chromatography this peak elutes at 4-8 ms and with preparative isoelectric focusing it demonstrates an isoelectric point of 8.6-9.0. This activity was susceptible to degradation by trypsin and neuraminidase, but was stable upon heating to 56 degrees C for 30 min. Its chemoattractant activity is predominantly chemokinetic by checkerboard analysis. As defined by chromatography, stability, and functional characteristics, this activity is similar to a recently described human lymphocyte chemoattractant lymphokine. This finding suggests that products of activated lymphocytes are present in blister fluids of patients with bullous pemphigoid and may contribute to the early influx of lymphocytes in this disease.

Blister↗
PubMed1983

Functional characteristics of histamine receptor-bearing mononuclear cells. I. Selective production of lymphocyte chemoattractant lymphokines with histamine used as a ligand.

Mitogens and antigens have been the traditional ligands for activating lymphocytes in vitro for the elaboration of lymphokines. Recently, histamine, by interaction with histamine-type 2 receptors on T lymphocytes, has been found to induce the production of one lymphokine, histamine-induced suppressor factor (HSF), that inhibits lymphocyte proliferation and lymphokine production in vitro. Because the biologic effects of HSF appear to be confined to alterations in lymphocyte function, we assessed the ability of soluble products of histamine-stimulated human blood mononuclear cells to affect another lymphocyte function, motility. Utilizing a modified Boyden chamber assay to assess lymphocyte migration, we identified chemoattractant activity for human blood and rat splenic T lymphocytes in histamine-induced mononuclear cell supernatants. No neutrophil or monocyte chemoattractant activity was present. Sephadex G-100 gel filtration of histamine-induced supernatants showed the lymphotactic activity eluted with a 56,000 m.w. This activity was cationic as determined by its elution pattern from a Sephadex QAE anion exchange matrix with a single pl of 9.0 to 9.4 determined by isoelectric focusing in sucrose. Its biologic activity is predominantly chemokinetic in nature, is stable to heating at 56 degrees C for 30 min, but is sensitive to the effects of trypsin and neuraminidase. These physicochemical and functional characteristics establish it as identical to a recently described concanavalin A-induced (Con A) lymphotactic lymphokine (LCF). Mononuclear cells that did not adhere to a histamine affinity matrix were unable to produce LCF when subsequently stimulated with histamine or Con A. Mononuclear cells incubated with histamine and diphenhydramine produced LCF; the addition of cimetidine eliminated LCF production. In fact, supernatants from cells incubated with histamine and cimetidine significantly inhibited lymphocyte migration, a phenomenon explainable by the two regions of lymphocyte migration inhibitory activity that were present in the Sephadex G-100 chromatography of crude histamine-induced supernatants. These data suggest that a subset of lymphocytes defined by the presence of histamine-type 2 receptors is capable of producing LCF while cells that bear histamine-type 1 receptors produce lymphocyte migration inhibitory activity.

Adult↗
PubMed1982

Opsonin-independent phagocytosis by human alveolar macrophages: augmentation by human plasma fibronectin.

A trypsin-sensitive membrane recognition unit that mediates phagocytosis of particulate activators of the human alternative complement pathway is present on human alveolar macrophages. Fragmented human plasma fibronectin selected by affinity chromatography with a monoclonal antifibronectin antibody augments this capacity. These data suggest a nonimmune mechanism for the clearance of some microorganisms from the opsonin-deficient microenvironment of the lung in which the alveolar macrophage is the principal resident phagocyte.

Fibronectins↗
PubMed1979

Inhibition of neutrophil chemotaxis in association with experimental angioedema in patients with cold urticaria: a model of chemotactic deactivation in vivo.

Deactivation is a phenomenon in which leucocytes exposed in vitro to a chemotactic factor in the absence of a concentration gradient are rendered relatively unresponsive to stimulation by a subsequent chemotactic gradient. In patients with idiopathic cold-induced urticaria, the elicitation of a local experimental angioedematous lesion causes the release of two chemotactic principles previously shown to deactivate leucocytes in vitro, high molecular weight neutrophil chemotactic factor (HMW-NCF) and eosinophil chemotactic factor of anaphylaxis (ECF-A), into the venous circulation draining the challenged extremity. However, biopsy specimens of lesional skin sites obtained for up to 24 hr show no infiltration of cells. For this reason, the in vitro chemotactic responsiveness of neutrophils to the chemotactic factor HMW-NCF and C5 fragments were assessed in three patients at various times after experimental challenge. Leucocytes from venous effluent draining an experimentally-induced angioedematous lesion were markedly impaired in their chemotactic responsiveness to both chemotactic factors 5 min after challenge, while cells taken from an unchallenged extremity at the same time responded normally. Cells from both arms were equally impaired in their responsiveness 1 hr later, thereby demonstrating that the chemotactic defect becomes systemic. The acquired defect was dissipated 4 hr after challenge. These data suggest that deactivation may occur in vivo and may alter host responsiveness in states where chemotactic factors are released into the circulation.

Angioedema↗
PubMed1977

Cold urticaria. Recognition and characterization of a neutrophil chemotactic factor which appears in serum during experimental cold challenge.

Sera were obtained from the venous effluents of cold-challenged arms of patients with idiopathic cold urticaria without plasma or serum cryoproteins; these sera exhibited increased neutrophil chemotactic activity without alterations of the complement system. A two- to fourfold augmentation of the base-line neutrophil chemotactic activity of serum from the immersed extremity began within 1 min, peaked at 2 min, and returned to base-line levels within 15 min, whereas there was no change in the serum chemotactic activity in the control arm. The augmented chemotactic activity in the serum specimens from the challenged arm of each patient appeared in a high molecular-weight region, as assessed by the difference in activity recovered after Sephadex G-200 gel filtration of the paired lesional and control specimens. Sequential purification of this high molecular-weight activity by anion- and cation-exchange chromatography revealed a single peak of activity at both steps. The partially purified material continued to exhibit a high molecular weight, being excluded on Sepharose 4B, and had a neutral isoelectric point. The partially purified material showed a preferential chemotactic activity for neutrophilic polymorphonuclear leukocytes, required a gradient for expression of this function, and exhibited a capacity to deactivate this cell type. This active principle, termed high molecular-weight neutrophil chemotactic factor, exhibited a time-course of release that could be superimposed upon that of histamine and the low molecular-weight eosinophil chemotactic factor and may represent another mast cell-derived mediator.

Chemotaxis, Leukocyte↗