title: Failure of inhibitory effects by platelets on super-oxide anion generation from stimulated neutrophils in a severe bronchial asthmatic.
abstract: Blood was drawn from healthy human volunteers and a 30-year-old woman with severe bronchial asthma (atopic and perennial type), whose peripheral blood platelets counts were continuously higher than 60 x 10(4)/mm3. Neutrophils were purified on a Conray-Ficoll gradient and platelets were isolated by a gel filtration method with Sepharose 2B. Superoxide anion (O2-) generation from the cells was measured by 2-methyl-6-[p-methoxyphenyl]-3,7-dihydroimidazo [1,2-a]purazin-3-one (MCLA)-dependent luminescence. Addition of 0.5 microM MCLA and 10(-8) M N-formyl-methionyl-leucyl-phenylalanine (fMLP) or 10 ng/ml phorbol myristate acetate (PMA) to a suspension of platelets obtained from the healthy controls and the patient caused no significant MCLA-dependent luminescence, 02- generation by neutrophils from healthy human volunteers, activated by 10(-8) M fMLP or 10 ng/ml PMA, was inhibited by their platelets in a concentration-dependent manner. Platelets from the patient failed to inhibit O2- generation from neutrophils activated by 10(-8)M fMLP. Cu-Zn superoxide dismutase concentrations in platelets from healthy human volunteers were not higher than the patient's. These data suggest that the absence of inhibition of superoxide generation from activated neutrophils by platelets might be involved in the pathogenesis of bronchial asthma.
authors.affiliation: Department of Internal Medicine, Gunma University School of Medicine, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Kurosawa
authors.forename: H
authors.initials: H
authors.lastname: Kobayashi
authors.forename: S
authors.initials: S
authors.lastname: Kobayashi
authors.forename: M
authors.initials: M
authors.lastname: Nakano
mesh_terms: D000328:Adult; D001249:Asthma / Q000097:blood* / Q000276:immunology; D001792:Blood Platelets / Q000502:physiology*; D002450:Cell Communication; D002850:Chromatography, Gel; D005260:Female; D006801:Humans; D007093:Imidazoles; D008163:Luminescent Measurements; D009504:Neutrophils / Q000502:physiology*; D010976:Platelet Count; D011719:Pyrazines; D013482:Superoxide Dismutase / Q000097:blood; D013481:Superoxides / Q000378:metabolism*
chemical_list: D007093:Imidazoles; D011719:Pyrazines; D013481:Superoxides; C063412:2-methyl-6-(4-methoxyphenyl)-3,7-dihydroimidazo(1,2-alpha)pyrazin-3-one; D013482:Superoxide Dismutase