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D N Landon

Publications and source records attributed to D N Landon.

49 records · Page 3Linked to original sources

A quantitative technique for growing human adult skeletal muscle in culture starting from mononucleated cells.

A quantitative and reproducible technique for establishing primary surface cultures from normal and diseased human muscle is described. Successful cultures were prepared from both fresh muscle and that stored up to 96 hr at 4 degrees C. The CPK activity of the muscle cells ranged between 0.5-3.0 micronmoles creatine per min per mg protein at 30 degrees C, thus indicating a high degree of differentiation. Spontaneous contractions were observed in 4 out of the 22 cultures established. Nerve cells were not required to achieve this level of differentiated function. No gross differences in plating efficiency, rate of myotube formation or CPK specific activity were found for the diseased muscle cells cultured so far. However, a 5--10-fold higher cell yield was obtained from muscles of patients with an inflammatory myopathy. The advantages of this technique for carrying out comparative studies on normal and dystrophic muscle cells are discussed.

Adult↗

Congenital myasthenia: further evidence of disease heterogeneity.

The findings in two cases of congenital myasthenia investigated by intercostal muscle biopsy are presented. The first case, a 16-year-old boy, showed reduced miniature endplate potential amplitude and normal 125I-alpha-bungarotoxin binding to postsynaptic acetylcholine receptors. Muscle biopsy and endplate ultrastructure were normal. Tubocurarine affinity, ion channel properties, and passive membrane properties were normal. Limited data showed reduced effectiveness of applied acetylcholine in opening ion channels. The second case was an 18-year-old girl with consanguineous parents. Type 2 muscle fiber atrophy was seen in both limb and intercostal muscle. Intercostal endplates were elongated, although ultrastructure was normal. Negligible postsynaptic alpha-bungarotoxin binding suggested an abnormality of the acetylcholine receptor macromolecule.

Adenosine Triphosphatases↗