ABSTRACT
The kD and Bmax values for [125I]endothelin-1 ([125I]ET-1) binding to the brain membrane preparations of 3- to 20-day-old chick embryos were compared. The kD values differed only slightly during development. In contrast, the Bmax values varied six-fold during the embryonic stages examined and displayed two distinct peaks, on day 5 (204 +/- 13 fmol/mg protein, n = 3) and day 13 (110 +/- 4 fmol/mg protein, n = 7) of incubation. Displacement of [125I]ET-1 binding to 5- and 13-day-old embryonic brain membrane preparations was carried out using ET-3 and BQ-123, a selective ETA receptor antagonist, as competing ligands. The results suggest that the ETA receptor subtype is primarily synthesized at the beginning of development followed by the production of non-selective ETB receptor subtype at a later time.
Subject(s)
Brain/growth & development , Brain/metabolism , Endothelin-1/pharmacology , Receptors, Endothelin/metabolism , Animals , Binding, Competitive , Chick Embryo , Dose-Response Relationship, Drug , Receptors, Endothelin/drug effects , Time FactorsABSTRACT
Process and office workers at a Swedish paper mill (n = 274) and dairy workers (n = 45) were investigated with questionnaires regarding skin symptoms. In the second part of the study, subjects reporting skin symptoms and a random sample of subjects without symptoms were examined and investigated with patch testing. Pruritus and skin irritation probably related to exposure to dust were found. The results do not indicate an increased prevalence of contact allergy. In two cases, positive patch test reactions to paper size (rosin) and a slimicide, mercaptobenzothiazole (MBT), were noted.
