Spinal muscular atrophy: DNA fragmentation and immaturity of muscle fibers.

The presence of apoptotic fibers and the embryonic proteins desmin and vimentin were investigated in muscle biopsy specimens from patients with spinal muscular atrophy (SMA). Apoptosis was studied in 24 cases of SMA by means of in situ end labeling of nuclear DNA fragmentation using TUNEL staining and immunohistochemistry. Apoptotic nuclei were observed in 54.

Morphologic and morphometrical study of the muscle spindle in muscular dystrophy.

Objective: To determine the morphologic and the morphometrical features of spindles in biopsies of patients with different types of muscular dystrophy and investigate the possible involvement of the spindle in the pathologic process of these diseases.

Study Design: The following variables were studied in biopsy specimens from 10 patients with Duchenne or Becker dystrophy, 9 with limb-girdle dystrophy, 3 with congenital dystrophy and 3 with facioscapulohumeral dystrophy: diameter and area of spindle; thickness of the capsule; number, diameter and area of intrafusal fibers; and number and area of nuclei.

Results: The statistical evaluation of the data showed significant differences regarding the thickness of the capsule, which was greater in patients than in controls, while the diameter and the area of the fibers were all smaller in patients than in controls.

Immunocytochemical study of cytoskeletal proteins in centronuclear myopathies.

The developmental status of muscle fibers was investigated in three cases of myotubular myopathy: one infant with the X-linked recessive form and two adult brothers with the autosomal, probably recessive, form of the disease. The presence of the developmentally regulated proteins desmin, vimentin and dystrophin was investigated by immunocytochemistry with the use of monoclonal antibodies. In the X-linked case, intense immunolabelling for vimentin and desmin was observed in the nuclear area of a great number of muscle fibers, while a few others showed sarcoplasmic dystrophin immunolabelling or were dystrophin-negative.

Morphological and morphometrical study of human muscle spindles in Werdnig-Hoffmann disease (infantile spinal muscular atrophy type I).

A study was made of the morphological and morphometrical features of muscle spindles in biopsies of patients with Werdnig-Hoffmann disease (infantile spinal muscular atrophy type I) to investigate the possible involvement of the muscle spindles in the pathological processes of the disease. A total of 57 muscle spindles from 26 cases were studied. The parameters determined were: the diameter and area of spindles, the number, diameter and area of intrafusal fibers, the number and area of nuclei.