PROTEIN SYNTHESIS IN MUSCLE CULTURES FROM PATIENTS WITH DUCHENNE MUSCULAR DYSTROPHY

Abstract

Muscle samples for cultures were obtained from the quadriceps by open biopsy under local anesthesia in 5 patients with the early stage of Duchenne muscular dystrophy (DMD) and 10 controls. Primary cultures were grown in Eagle''s Minimum Essential Medium (MEM) with 20% fetal calf serum. After 4 wk, cells were trypsinized, counted and subcultured for 5 days in MEM with 5% horse serum and finally incubated for 4 h with (3H)-leucine. Total protein synthesis showed a significant decrease (half of control values) only in muscle cultures from patients with DMD. Addition of CaCl2 alone or the ionophore, with 2-[(3.beta.,9.alpha.,11.beta.-trimethyl)-8-2(2-pyrrolecarboxymethyl)-1,7-dioxaspiro[6,6]undecyl-2.beta.-methyl]-5methylaminobenzoxazole-4-carboxylic-acid normalized this defect in protein synthesis. By contrast, myosin heavy chain synthesis was measured and found normal in all patients.