title: Isolated erythrocyte membranes of transfusion-dependent and non-transfused thalassemia patients in Jakarta, investigated by electron paramagnetic resonance spectroscopy.
abstract: Erythrocyte membrane structural parameters were studied in transfusion-dependent beta-thalassemia patients, in long-term transfused patients (regularly transfused < 15 years), and in those who had not yet obtained transfusions. Controls were voluntary students up to 30 years of age without diagnosis or clinical signs of thalassemia. Membranes were isolated and investigated by sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE) and electron paramagnetic resonance (EPR) spectroscopy. Data obtained from the thiol-reactive spin label N-ethyl-maleimidoproxyl reveal immobilization of protein environment in erythrocyte membranes from thalassemic patients. SDS-PAGE shows both degradation and aggregation of membrane proteins. Thalassemic erythrocyte membranes exert higher order parameters in the hydrophobic region as determined by 16-doxyl-stearic acid. Rotational correlation times of this spin label increase only in transfused patients. Polarity is higher in membranes of all patients than in controls. In the polar interface, order parameters obtained from 5-doxyl-stearic acid increase in non-transfused and decrease in transfusion-dependent patients as compared with controls. Transfused patients exert increasing membrane order in the hydrophobic region and counter-currently decreasing order in the polar interface indicating loss of membrane integrity along with the loss of fluidity and polarity gradients and the loss the energetic barrier function of the membrane.
authors.affiliation: Department of Physics, Faculty of Mathematics and Natural Science, University of Indonesia, Depok, Indonesia. seruni@chem.usyd.edu.au
authors.forename: Seruni K
authors.initials: SK
authors.lastname: Udyaningsih-Freisleben
authors.forename: Vita
authors.initials: V
authors.lastname: Kurniati
authors.forename: Pamulih B
authors.initials: PB
authors.lastname: Prasetyo
authors.forename: Sri
authors.initials: S
authors.lastname: Handayani
authors.forename: Chris
authors.initials: C
authors.lastname: Adhiyanto
authors.forename: Rondang R
authors.initials: RR
authors.lastname: Soegianto
authors.forename: Ratna
authors.initials: R
authors.lastname: Pudiantari
authors.forename: Bulan G
authors.initials: BG
authors.lastname: Munthe
authors.forename: Wahyuning
authors.initials: W
authors.lastname: Ramelan
authors.forename: Hans-Joachim
authors.initials: HJ
authors.lastname: Freisleben
mesh_terms: D000293:Adolescent; D000328:Adult; D001803:Blood Transfusion; D002648:Child; D004578:Electron Spin Resonance Spectroscopy; D004591:Electrophoresis, Polyacrylamide Gel; D004910:Erythrocyte Membrane / Q000737:chemistry* / Q000378:metabolism; D005260:Female; D006801:Humans; D007214:Indonesia; D008297:Male; D008560:Membrane Fluidity; D012016:Reference Values; D013113:Spin Labels; D013995:Time; D017086:beta-Thalassemia / Q000097:blood* / Q000628:therapy
chemical_list: D013113:Spin Labels