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Biomedical subjects

S I Wasserman

Publications and source records attributed to S I Wasserman.

At least 73 records · Page 4Linked to original sources
PubMed1984

Adenosine receptors on mouse bone marrow-derived mast cells: functional significance and regulation by aminophylline.

Adenosine receptors on mouse bone marrow-derived mast cells were identified by functional criteria and radioligand binding. The stimulated release of beta-hexosaminidase from these cells was significantly augmented by the simultaneous addition of secretagogue and adenosine, NECA, or L-PIA. Similar enhancement of pre-formed mediator release occurred after a 10-min preincubation with adenosine. Resting mast cell cAMP levels increased within 15 sec after the addition of adenosine, and remained elevated for at least 60 sec. Although the antigen-or A23187-induced release of beta-hexosaminidase was markedly potentiated by exogenous adenosine, the stimulated release of [14C]-labeled arachidonic acid metabolites was minimally affected by adenosine, suggesting a differential effect of adenosine on granule-associated release as compared to generated mediator release. Bone marrow mast cells exhibited 5470 +/- 740 [3H]adenosine binding sites/cell, with a binding affinity of 24.4 +/- 3.8 nM. Cells cultured in the presence of 100 microM aminophylline for 6 days were hyperresponsive to exogenous adenosine, releasing a maximum of 162% of the amount of beta-hexosaminidase released from control cells in the presence of adenosine. The number of [3H]adenosine binding sites on the xanthine-treated cells increased to 156% of control values, suggesting an up-regulation of adenosine receptors induced by chronic exposure to an adenosine receptor antagonist. Mouse bone marrow mast cells possess functionally significant adenosine receptors that are regulated by aminophylline and that, when stimulated, produce many alterations in the mast cell secretory process.

Adenosine↗
PubMed1983

Inhibition of rat mast cell arachidonic acid cyclooxygenase by dapsone.

Dapsone (diaminodiphenylsulfone) has been used therapeutically for a variety of disorders in which mast cell participation has been demonstrated, including bullous pemphigoid and some form of necrotizing vasculitis. The mechanism of action of dapsone in these disorders is unknown but potentially relates to inhibition of mast cell activation and prevention of generation and/or release of mast cell mediators. Evidence for this possibility has been obtained in rat mast cells in which dapsone in a concentration-dependent manner prevented generation of prostaglandin D2 PGD2 from exogenous or endogenous arachidonic acid with 50% inhibition achieved at 1 and 0.2 to 0.4 mM, respectively. Dapsone inhibited cyclooxygenase conversion of arachidonic acid to PGD2 but not the GSH-dependent conversion of 14C-PGH2 to PGD2 by PGH-D isomerase in broken cell preparations. Dapsone prevented the immunologic generation of PGD2 from antigen-challenged rat mast cells but did not affect the release of histamine. Thus dapsone may exert some of its therapeutic effects by prevention of mast cell PGD2 generation.

Animals↗
PubMed1983

Modulation of rat serosal mast cell biochemistry by in vivo dexamethasone administration.

To examine steroid-induced biochemical alterations in the mast cell secretory process, rats were injected with intramuscular dexamethasone or saline for 4 days, and serosal mast cells and lung tissue were obtained from each group. Radioligand binding studies utilizing 1-[propyl-1,2-3H]dihydroalprenolol (3H-DHA) demonstrated a 23.1 +/- 0.8% increase in rat lung beta-adrenergic receptors in steroid-treated rats, but the mast cell beta-adrenergic receptors were unaffected. Neither resting mast cell cyclic adenosine 3':5'-monophosphate (cAMP) levels nor the degree of cAMP augmentation induced by isoproterenol were changed by steroid administration. Mast cells from rats treated with dexamethasone released only 48.6 +/- 8.9 and 58.8 +/- 6.0% of the beta-hexosaminidase released from saline-treated rat mast cells when sensitized with anti-dinitrophenyl (DNP) IgE and challenged with DNP-bovine serum albumin antigen or the calcium ionophore A23187, respectively. [3H]serotonin release in cells from steroid-treated rats was 41.8 +/- 7.9 and 87.6 +/- 2.6% of control release stimulated by antigen or A23187, respectively. [14C]arachidonic acid incorporation into mast cell phospholipids followed by antigen or A23187 challenge revealed that cells from dexamethasone-treated rats release 61.3 +/- 15.6% and 62.1 +/- 11.8% of labeled metabolites, respectively, compared to controls. The addition of exogenous arachidonic acid 5 min prior to antigen challenge caused a similar decrease in mediator release in cells from saline- and steroid-treated rats (36.7 +/- 6.1 and 38.4 +/- 0.9%, respectively). When arachidonic acid was added to sensitized cells after specific antigen, no significant changes in beta-hexosaminidase release were noted in either group. Chronic in vivo dexamethasone administration markedly decreases mast cell mediator release without changing resting cAMP levels. The release of arachidonic acid metabolites is reduced in steroid-treated cells, possibly through the inhibition of phospholipases. Exogenous arachidonic acid cannot overcome this inhibition, suggesting that an earlier step in phospholipid metabolism, perhaps involving phospholipase C, may be important.

Animals↗
PubMed1982

The isolation, identification and characterization of sulfated glycosaminoglycans synthesized in vitro by human eosinophils.

Human eosinophils were purified to greater than 92% using 16-30% metrizamide gradients, and these cells cultured for up to 72 h in vitro to label sulfated glycosaminoglycans. Over 90% of the sulfated glycosaminoglycan-containing material was extracted in 4 M guanidine HCl and had a hydrodynamic size similar to a glycosaminoglycan marker with an approximate average molecular weight of 60,000. Treatment of this salt-extracted 35S-labeled glycosaminoglycan-containing material with 0.5 M NaOH resulted in a change in mass to approx. 20,000 daltons, suggesting that the larger molecules were proteoglycans with side chains with an approximate molecular weight of 20,000. These salt extracted presumptive 35S-labeled proteoglycans were protease insensitive and behaved in a highly charged fashion on DEAE-cellulose. The composition of 35S-labeled glycosaminoglycans from human eosinophils as identified using selected polysaccharides was 70-81% chondroitin 4-sulfate, 9-12% chondroitin 6-sulfate, and 5-12% dermatan sulfate. The predominance of chondroitin 4-sulfate in human eosinophils is similar to the predominance of chondroitin 4-sulfate in human neutrophils and human platelets.

Cell Separation↗
PubMed1982

Serum eosinophilotactic activity in eosinophilic fasciitis.

Serum eosinophil chemotactic activity was determined by the Boyden chamber technique in 20 patients with eosinophilic fasciitis. Increased eosinophil chemotactic activity (greater than 125% of background) was found in all 20 patients (mean 297% +/- 129), whereas sera of 20 controls with systemic sclerosis and diffuse scleroderma had increased eosinophil chemotactic activity in only 6 (30%) instances (mean 96% +/- 47, P less than 0.001). Although serum eosinophil chemotactic activity decreased over time in all 8 eosinophilic fasciitis patients studied longitudinally, this activity returned to normal in only 3, all of whom received prolonged courses of corticosteroids. Preliminary data suggest the existence of a eosinophilotactic serum factor common to patients with eosinophilic fasciitis.

Adrenal Cortex Hormones↗
PubMed1982

Rat lung cholinergic receptor: characterization and regulation by corticosteroids.

Muscarinic cholinergic receptors have been implicated in the regulation of bronchomotor tone, bronchial mucus secretion, and lung mast-cell mediator release. Rat lung membranes prepared by homogenization, sonication, and sedimentation of 37,000 g in sucrose have been demonstrated to possess muscarinic cholinergic receptors as assessed by radioligand binding employing l-quinuclidinyl[phenyl-4-3H]benzilate ([3H]QNB). QNB binding was saturable, stereoselective, and reversible in the presence of 1 microM atropine. The rat lung muscarinic receptor demonstrated a Kd of 0.268 +/- 0.126 (+/- SD) nM and a density of 35.4 +/- 4.6 fmol/mg protein by Scatchard analysis. The Hill coefficient was 1.015 +/- 0.085, indicating noncooperative binding. Muscarinic cholinergic receptors in the rat lung were equal in number to alpha 1-adrenergic receptors, but beta-adrenergic receptors are 14 times more prevalent as defined by [3H]prazosin and l-[propyl-2, 3-3H]dihydroalprenolol ([3H]DNA) binding. Dexamethasone (140 micrograms) administration in vivo caused an increase in all three receptor types by 24-48 h, suggesting steroids regulate not only the number of beta-receptors but also that of alpha- and cholinergic receptors. These data suggest new avenues by which steroids may regulate lung function.

Adrenal Cortex Hormones↗
PubMed1982

Characterization of the rat mast cell beta-adrenergic receptor in resting and stimulated cells by radioligand binding.

Rat serosal mast cell beta-adrenergic receptors were characterized both functionally by assessing changes in histamine release and cyclic 3',5' adenosine monophosphate (cAMP) levels and directly by radioligand binding studies using [3H]dihydroalprenolol ([3H]DHA), a beta-adrenergic antagonist. Mast cells were obtained by lavage of the pleural and peritoneal cavities of Sprague-Dawley rats and were purified on metrizamide gradients to greater than 95% purity. Resting mast cells stimulated with beta-adrenergic agonists demonstrate a marked rise in cAMP levels after a 15-sec incubation. However, the same concentrations of these agonists have no effect on IgE-mediated mast cell histamine release. [3H]DHA binding to intact mast cells is rapid, reversible, saturable, and stereoselective. The cells possess 40,000 +/- 14,000 beta-adrenergic receptors/cell and demonstrate a binding affinity of 1.58 +/- 0.56 nM for [3H]DHA. Competition studies reveal that 83.5% of the receptors are of the beta 2 subtype and 16.5% are beta 1. Neither sensitization with anti-DNP-BSA IgE nor subsequent challenge with specific antigen alters mast cell beta-adrenergic receptor characteristics. Rat mast cells possesses large numbers of high affinity beta-adrenergic receptors, primarily of the beta 2 subtype, coupled to adenylate cyclase, but the role of these receptors in mast cell secretory events is not yet established.

Adrenergic beta-Agonists↗
PubMed1982

Mast cells in allergic diseases and mastocytosis.

Mast cells with their stores of vasoactive and chemotactic mediators are central to the pathogenesis of allergic diseases. The cross-linking of receptorbound IgE molecules on the surface of mast cells initiates a complex chain of events, including calcium ion influx, phospholipid methylation and turnover and cyclic nucleotide metabolism, ultimately resulting in the release of mediators of immediate hypersensitivity. These mast cell mediators are important in smooth muscle reactivity, in the recruitment of eosinophilic and neutrophilic leukocytes and in the generation of secondary chemical mediators. Histologic evidence of mast cell degranulation, biochemical evidence of mast cell mediators in blood and tissues and clinical evidence of signs and symptoms reproducible by these mediators have strongly supported the crucial role of mast cells in asthma, urticaria, anaphylaxis, rhinitis and mastocytosis. Because of their unique location at host environment interfaces, mast cells may both participate in allergic diseases and promote homeostasis.

Anaphylaxis↗
PubMed1982

The functional and physicochemical characterization of three eosinophilotactic activities released into the circulation by cold challenge of patients with cold urticaria.

The eosinophilic activity appearing in the venous effluent of the cold-induced angioedematous extremity of patients with cold urticaria has been resolved into three fractions by gel filtration and Dowex-1 chromatography. The low molecular weight activity, 300-700 mw, is highly acidic while the activity of 1000-3000 mw is composed of highly acidic and less acidic moieties. Each of the three activities has a different retention time on high pressure liquid chromatography, indicating that they represent distinct fractions which differ in size, charge, and hydrophobicity. Each fraction requires a gradient to attract eosinophils in a dose-response fashion and each deactivates eosinophils at subchemotactic concentrations. The more acidic 1000-3000 mw fractions also attract human monocytes in a chemotactic gradient at concentrations identical to those which attract human eosinophils. These three classes of eosinophil chemotactic activities and the activity for monocytes appear and disappear from the venous effluent with essentially the same time course as a distinct neutrophil chemotactic factor and histamine with cold induction of angioedema in patients with cold urticaria. The elaboration of these diverse chemoattractants in experimentally induced physical allergy provides potential pathways for mast cell-mediated infiltrative reactions.

Angioedema↗
PubMed1980

Release of mast-cell mediators and alterations in lung function in patients with cholinergic urticaria.

Cholinergic urticaria was elicited in seven subjects by experimental challenge that consisted of running on a treadmill in a plastic occlusive suit. A sensation of generalized warmth of the skin was followed by pruritus, erythema, urticaria, and transient respiratory-tract symptoms consisting of shortness of breath or wheezing or both. Statistically significant falls in one-second forced-expiratory volumes (FEV1), maximal midexpiratory flow rates (MMF), and specific conductance (SGaw) and a rise in residual volume were detected. The serum histamine concentration rose, with an augmentation of eosinophil and neutrophil chemotactic activities. Gel-filtration chromatography showed that the eosinophil chemotactic activity consisted of at least two principles. The chemotactic activities are similar in magnitude to those recognized in other skin disorders dependent on mast cells. These observations extend to the lungs the manifestations of a condition previously thought to be restricted to the skin.

Adult↗
PubMed1980

Isolation and characterization of sulphated mucopolysaccharides from rat leukaemic (RBL-1) basophils.

Proteoglycans of 300 000 mol.wt. were isolated from dispersed rat basophil tumour cells after labelling of the sulphated mucopolysaccharides with 35S in vitro:90% of the 35S-labelled mucopolysaccharides were extracted at high salt concentration. Alkali degradation of the 35S-labelled proteoglycans yielded glycosaminoglycan chains of 40 000 mol.wt. The composition of the salt-extracted 35S-labelled mucopolysaccharides, as defined by parallel or sequential degradation with chondroitinase AC, chondroitinase ABC and heparinase and resolution of the disaccharide-digestion products obtained with chondroitinase AC, was 48--61% chondroitin 4-sulphate, 20--30% dermatan sulphate, 10--15% heparin and 7--9% chondroitin 6-sulphate. Most of the salt-extracted 35S-labelled mucopolysaccharides were highly charged, with heparin and chondroitin 6-sulphate being relatively uniform in this regard, whereas chondroitin 4-sulphate and dematan sulphate exhibited a range of charge characteristics. The diversity of sulphated mucopolysaccharides present in the rat leukaemic basophil is in contrast with the predominance of heparin in the rat mast cell.

Animals↗