Osmotic stability of erythrocytes in human muscular dystrophy before and after phospholipase treatment.

The stability of washed erythrocytes from patients with muscular dystrophy was determined in hypotonic phosphate buffered sodium chloride. Control cells were more stable than cells from Duchenne and myotonic patients. After pretreatment of the cells with phospholipase from pancreas, snake venom or bee venom in the presence of 14 mmol/l Ca2+, the order of osmotic stability in the 3 groups was not changed. In isotonic phosphate buffered NaCl, however, the erythrocytes of the myotonic patients were much more stable than the cells of the Duchenne and the control group. The lytic process was further studied in control cells with pancreatic phospholipase. 21 +/- 3 (S.E.M.) % of the cells were lysed. This process was (partly) prevented by omitting the phospholipase, by replacement of Na+ by K+ or Li+, by lowering the Ca2+ concentration, by omitting phosphate, by ouabain, by glucose, by ribose, by sucrose, by tetrodotoxin, a Na+-transport inhibitor. Blocking of the Ca2+ transport by La3+ or mersalyl, greatly stimulated the lytic process.