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Ultrastructural studies have shown plasmalemmal defects in a proportion of non-necrotic muscle fibers in Duchenne dystrophy, suggesting that intracellular calcium overloading may be an important mechanism of muscle fiber degeneration. To investigate this assumption, we studied the localization of calcium with the von Kóssa method, with alizarin red, and with glyoxalbis-(o-hydroxyanil) in serial, fresh-frozen sections of 114 biopsy specimens. The biopsy material included Duchenne dystrophy (24 cases), other dystrophies (27 cases), inflammatory myopathies (47 cases), and normal controls (11 cases). Counted in each specimen were every muscle fiber, the so-called large-dark fibers, and all calcium-positive fibers. Separate counts were made of the large-dark, necrotic, and other types of calcium-positive fibers. In Duchenne dystrophy, non-nectotic calcium-positive fibers occurred with a mean frequency of 4.83 percent. For all other groups, the corresponding value was 0.57 percent, with a range of 0.21 percent (normals) to 1.76 percent (scleroderma), p less than 0.001. Large-dark fibers were 12 times more common in Duchenne dystrophy than in all other cases. Forty-three percent of the fibers were calcium-positive in Duchenne dystrophy, whereas calcium-positive large-dark fibers were extremely rare in the other cases.

The prevalence of epilepsy in children and adolescents from birth through age 19 years was determined for residents of two counties in central Oklahoma. Cases, identified from hospitals, clinics, private physicians' offices, and EEG laboratory and emergency room records, numbered 1,159, yielding a prevalence rate of 4.71 per 1,000. The prevalence was highest in children aged 1-4 years. Overall, males had a slightly higher prevalence rate than females (M:F = 1.1). However, the male/female ratio varied by age, with the group aged less than 1 year having the highest ratio (M:F = 1.5), and by type of epilepsy, with males having higher rates of simple partial epilepsy (M:F = 1.8) and infantile spasms (M:F = 1.5). The prevalence of epilepsy was higher in blacks than in whites. Differences in prevalence by race were confined primarily to generalized epilepsies (B:W = 1.8). The most common types of epilepsy were tonic, clonic, and tonic-clonic (1.14 per 1,000), complex partial (0.39 per 1,000), and partial seizures secondarily generalized (0.33 per 1,000). Approximately 70% of cases were considered idiopathic. Among the presumed causes were perinatal factors (7%), trauma (4%), central nervous system (CNS) infection (3%), and congenital/developmental factors (3). Sixty-five percent of cases had at least one additional medical problem. The most common types of comorbidity were motor handicap (13%) and developmental delay (24%).