Membrane processes in myotonic dystrophy during in vitro aging of erythrocytes.

The present communication is devoted to investigating the possibility that in myotonic dystrophy (MyD) a decreased ATP utilization by the membrane may produce modifications in glycoprotein structure and/or in the supramolecular arrangement of some membrane proteins. The study was carried out a) by determining the membrane sialic acid content and the cellular ATP concentration in 10 cases of MyD, b) by evaluating the structural modifications of membrane glycoproteins occurring during in vitro incubation, c) by testing the presence on the membrane of high molecular weight aggregates of proteins, and d) by evaluating the distribution of hydrophobic and hydrophilic domains of the membrane by using 1-anilino-8-naphthalene sulfonate (1,8 ANS) as a fluorescent probe. Our evidence suggests that the ATP concentration and membrane sialic acid content are within normal values. Only in two cases did structural modifications of membrane glycoproteins occur while the supramolecular assembly of membrane proteins could be considered normal. The fluorescent probe behaviour after in vitro aging was indicative of a decreased polarity of its environment.