title: The international collaborative study on the first international standard of birch (Betula verrucosa)-pollen extract.
abstract: A selected candidate international standard preparation of birch (Betula verrucosa)-pollen extract was studied together with other birch-pollen extracts in a multinational study involving 20 laboratories in 11 countries. The biologic activity of the extract had previously been demonstrated in quantitative skin prick testing. The study methods comprised RAST inhibition, histamine release, quantitative immunoelectrophoresis, isoelectric focusing, and other methods. The results from RAST inhibition were calculated as parallel-line assays with statistical tests for linearity and parallelism. Analysis of variance was applied to test the significance of differences between potency estimates. In all assay methods, the candidate standard could be used to assign relative potencies to other birch-pollen extracts. The candidate standard was adequately stable during 36 months of storage at or below 5 degrees C. On the basis of this study, the World Health Organization has established the preparation as the International Standard for birch-pollen extract with assigned units of 100,000 IU per ampule.
authors: Norwegian Medicines Control Authority, Oslo.
authors: F C
authors: FC
authors: Arntzen
authors: T W
authors: TW
authors: Wilhelmsen
authors: H
authors: H
authors: Løwenstein
authors: B
authors: B
authors: Gjesing
authors: H J
authors: HJ
authors: Maasch
authors: R
authors: R
authors: Strömberg
authors: R
authors: R
authors: Einarsson
authors: A
authors: A
authors: Backman
authors: S
authors: S
authors: Mäkinen-Kiljunen
authors: A
authors: A
authors: Ford
mesh_terms: D001667:Binding, Competitive; D004355:Drug Stability; D004591:Electrophoresis, Polyacrylamide Gel; D006636:Histamine Release; D006801:Humans; D007391:International Cooperation; D007525:Isoelectric Focusing; D010936:Plant Extracts / Q000032:analysis / Q000592:standards*; D010940:Plant Proteins / Q000032:analysis; D011058:Pollen / Q000032:analysis*; D011852:Radioallergosorbent Test; D012015:Reference Standards; D012016:Reference Values; D014197:Trees / Q000276:immunology*; D014944:World Health Organization
chemical_list: D010936:Plant Extracts; D010940:Plant Proteins