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Biomedical subjects

A K Sobotka

Publications and source records attributed to A K Sobotka.

At least 19 recordsLinked to original sources
PubMed1986

Dirofilaria immitis: diethylcarbamazine-induced anaphylactoid reactions in infected dogs.

The immunopathogenesis of the anaphylactoid Mazzotti reactions has been studied by comparing physiologic and immunologic aspects of diethylcarbamazine-induced shock in Dirofilaria immitis infected dogs with antigen induced anaphylaxis in infected and uninfected controls. Filarial antigen, specific host IgG antibody, and C1 and C3 complement levels were quantitatively measured over time in relation to the levels of histamine and prostaglandin D2 in the blood and changes in mean blood pressure. D. immitis antigen injected into uninfected dogs having no detectable IgG antibody to D. immitis or Toxocara canis produced a rapid drop in blood pressure that paralleled a drop in C1 and C3 levels and an increase in prostaglandin D2. Antigen injected into infected dogs with IgG antibody produced a similar drop in blood pressure and complement and increase in prostaglandin D2 which differed from the uninfected group only in the slower clearance of antigen from the blood. Diethylcarbamazine alone produced no measurable changes in blood pressure or complement in uninfected hosts. Diethylcarbamazine, however, administered into skin test positive infected dogs, produced a temporally slower but quantitatively similar loss in blood pressure, drop in complement, and increase in prostaglandin D2 and histamine to that induced by antigen injection. Complement activation and immune complex formation are initiated by antigen release, and subsequent vasoactive mediator release leads to shock with prostaglandin D2 being quantitatively higher in blood than is histamine.

Airway Resistance↗
PubMed1983

Comparative studies of human basophils and mast cells.

Atopic disease in humans results primarily from the activity of tissue mast cells and circulating basophils. These two very similar cell types have recently been purified to near homogeneity and studies have begun to identify the biochemical mechanisms of mediator release, to explore the effects of pharmacologic manipulation of the response, and to determine unambiguously which mediators are derived from mast cells and basophils. This report will review studies examining various parameters of histamine release, the role of cyclic AMP in histamine release, and the production of arachidonic acid metabolites and their pharmacologic modulation.

Animals↗
PubMed1983

Immunochemical studies of yellowjacket venom proteins.

The major proteins of yellowjacket venoms have been isolated and characterized immuno-chemically. They consist of hyaluronidase, phospholipase, and antigen 5. Venoms from three species of yellowjacket were studied. Vespula germanica, V. maculifrons, and V. vulgaris. The phospholipases could be isolated in good yield only when affinity chromatography was used to minimize limited proteolysis. A kallikrein-like peptidase was found present in the yellowjacket venom. Phospholipases from these three species were immunochemically indistinguishable from each other, as were their antigen 5s. Sera from individuals sensitive to yellowjacket venom contained IgE and IgG specific for antigen 5 and phospholipase.

Amino Acids↗
PubMed1980

Modulation of the rate of histamine release from basophils by cyclic AMP.

Rates of histamine release from human basophil leukocytes have been studied in response to three different stimuli: antigen, ionophore A23187 and strontium ions. Dibutyryl cycle AMP and other agents which are assumed to cause a rise in intracellular levels of cyclic AMP accelerate the release of histamine induced by all of the stimuli. In addition, dibutyryl cyclic AMP caused an inhibition of the maximum release obtainable with antigen stimulation but no inhibition of the maximum release obtainable with ionophore A 23187 or with strontium ions alone.

Basophils↗
PubMed1980

A controlled study of the effectiveness of the Rinkel method of immunotherapy for ragweed pollen hay fever.

In a double-blind study, we compared the effects of the Rinkel method of immunotherapy with ragweed pollen extract and placebo on symptoms of ragweed hay fever and immunologic parameters in 24 ragweed-sensitive patients. Each had a skin-test end point by Rinkel serial dilution titration to ragweed pollen extract at 1:312,500 w/v or greater dilution, a 2 + skin test to ragweed AgE at 0.1 microgram /ml or greater dilution, and in vitro leukocyte histamine release by ragweed pollen extract. None had had immunotherapy for at least 7 yr. Patients matched on the basis of leukocyte histamine release by ragweed were assigned to two treatment groups (12 patients in each group). One group received ragweed pollen extract, and the other, placebo, both administered by the Rinkel method between June and October, 1978. Treatment doses were derived from skin-test end points. The median maintenance ("optimal dose") for patients receiving ragweed pollen extract was 0.53 ml of 1:312,500 w/v and the mean cumulative dose of ragweed pollen extract given during the study contained 0.094 micrograms of ragweed AgE. Symptom-medication scores of all patients rose and fell with ragweed pollen counts. No significant differences were observed in mean daily symptom-medication scores, antiragweed IgG or IgE levels, leukocyte histamine release by ragweed, total IgE levels, or skin-test end-point dilutions with ragweed pollen extract between the group receiving ragweed pollen extract and the group receiving placebo. Despite the absence of specific effect on symptom-medication scores and measured immunologic variates, 10 3f the 12 ragweed-treated patients and 10 of the 12 placebo-treated patients were of the opinion that their hay fever symptoms during the ragweed pollen season were less severe in 1978 than in 1977 and that they had been helped by Rinkel method immunotherapy. Under the conditions of the study, Rinkel method immunotherapy with ragweed pollen extract was no more effective than placebo given in an imitation of the Rinkel method.

Adolescent↗
PubMed1980

Effect of theophylline and terbutaline on immediate skin tests.

A questionnaire survey of board-certified allergists revealed that conflicting ideas exist as to the effect that drugs such as theophylline and beta 2 agonists have an immediate skin tests. Approximately half of the respondents felt these drugs would obscure a skin response; the remainder would not withdraw the drugs prior to testing. As a result of this difference in opinion, we studied the effects of these drugs on skin tests in seven subjects taking terbutaline (5 mg three times daily) and 13 subjects taking theophylline (3 to 5 mg/kg every 6 hr). Neither an acute loading dose nor chronic administration of either drug singly produced significant changes in wheal size in response to histamine, ragweed, or grass allergens. We conclude that theophylline and terbutaline administered singly at these doses have no effect on immediate skin tests.

Administration, Oral↗
PubMed1979

Solid phase radioimmunoassay for quantitation of antigen-specific IgG in human sera with 125I-protein A from Staphylococcus aureus.

Radiolabeled protein A from Staphylococcus aureus (Staph A) has been used to develop a solid phase, noncompetitive radioimmunoassay for quantitation of specific IgG antibody. The assay involves two incubations: First, agarose-insolubilized antigen is mixed with serum samples for 1 to 4 hr during which specific antibody is bound; second, after a washing procedure, the solid phase immune complexes are incubated for 4 to 18 hr with 125I-Staph A, during which the radiolabeled detection protein binds to the insolubilized specific IgG antibody. In a comparative study of the IgG antiphospholipase A antibody content of 23 human sera drawn from honeybee venom-sensitive patients, resulted of the Staph A assay correlated highly (r = 0.981, p less than 0.001, N = 23) with those obtained from a liquid phase, competitive radioimmunoprecipitation (double antibody) assay. The two assays demonstrated comparable precision, sensitivity, and reproducibility. In contrast, the use of 125I-Staph A in the solid phase radioimmunoassay was superior to 125I rabbit anti-human IgG because of lower negative serum (blank) values, shorter time required to reach equilibrium binding, and greater precision and reproducibility. In principle, the 125I Staph A assay may be applied ot IgG quantitation for crude allergen extracts as well as purified antigens. Furthermore, the sera of a number of mammalian species may be studied without further modification.

Animals↗
PubMed1979

The action of strontium on basophil leukocytes and its use to probe the relationship between immunologic stimulus and secretory response.

Strontium will substitute for calcium in the activation of histamine secretion from human basophil leukocytes stimulated by an immunologic reaction or by the ionophore A23187. Strontium is required in 10-fold higher concentration (1 to 10 mM) to activate histamine release compared with calcium (0.1 to 1.0 mM). In terms of maximum release obtainable for a particular immunologic stimulus, strontium is more effective than calcium. Results are presented to show that calcium and strontium act at the same site but strontium is a more sensitive probe for that site. Strontium can be used to demonstrate that immunologic stimuli activate calcium-binding sites in basophils even when no secretion is observed in the presence of calcium. It is suggested that the degree of secretion observed from basophils depends on the number of occupied Fc receptors for IgE and the coupling of these Fc receptors to calcium transport sites.

Basophils↗
PubMed1979

Some invariant properties of IgE-mediated basophil activation and desensitization.

We investigate certain general properties of antigen induced degranulation of sensitized basophils by analyzing two types of experiments: Experiments in which we expose basophils to two antigens sequentially and then determine the fraction of histamine released; and experiments in which we obtain time-dependent release and desensitization curves. To analyze the latter type of experiments we introduce a new way to plot release and desensitization data that depends on the nature of the interactions of histamine-containing units (histamine quanta) with themselves or the cells degranulation apparatus, but not on any specific properties of the antigen. From our analysis we conclude that: 1) A fraction of histamine within a population of basophils is nonreleasable by antigenic stimulation. 2) When a basophil degranulates the initial release of histamine appears to inhibit subsequent release. 3) The rate of histamine release is proportional to the amount of releasable histamine remaining in the cells when the amount remaining is small, as expected if release of histamine granules is a stochastic process. 4) There is no dependence of desensitization on the extracellular calcium concentration.

Antigens↗
PubMed1978

Protein allergens of white-faced hornet, yellow hornet, and yellow jacket venoms.

White-faced hornet, yellow hornet, and yellow jacket venoms have very similar protein compositions; each contains mainly three basic proteins. Two of these proteins have hyaluronidase and phospholipase activities and the third one, designated as antigen 5, is of as yet unidentified biochemical function. These three proteins have molecular weights of about 45 000, 35 000, and 25 000, respectively. The three proteins of white-faced hornet venom have been purified to near homogeneity, while this is the case only for antigen 5 of yellow hornet and yellow jacket venoms. Strong antigenic cross-reaction of the hyaluronidase from these three vespid venoms was observed using specific rabbit anti-venom sera, while weak cross-reactions of phospholipases and of antigen 5s were observed. All three proteins are active as allergens to varying degrees in vespid sensitive individuals. With each vespid venom its antigen 5 seems to be the major allergen. The results help to clarify the commonly observed varying degrees of multiple sensitivity of people to different vespids.

Allergens↗