Histometric and electron cytochemical study of muscle in the dystrophic mouse.

A histometric analysis of the alterations at the motor end plate in dystrophic Bar Harbor mice has been performed. In both forms of mouse dystrophy, simplification and focal atrophy of the junctional folds and retraction of the nerve terminal represented the significant changes. The postsynaptic alterations were similar to those described in Duchenne dystrophy. In constrast, the presence of presynaptic alterations in these mice indicated the presence of both a neural and a muscular abnormality. The wedge-shaped focal lesions in the muscle of dystrophic mice were demonstrated by both in vitro and in vivo HRP tracer techniques. These focal degenerative changes in muscle were similar to those described in Duchenne dystrophy. Employing the technique of extracellular space tracing, a comparison was made of the appearance of the transverse tubular system in the various types of dystrophic muscle fibers.

The correlation of arterial lesions with umbilical artery Doppler velocimetry in the placentas of small-for-dates pregnancies.

The placentas of 14 growth-retarded fetuses with abnormal umbilical artery velocimetry and 15 appropriately grown fetuses with normal waveforms were collected immediately after delivery and analyzed in a blinded fashion. A large percentage of the arterial vessels in the placentas from the former group showed abnormal changes in the vessel wall. The percentage of abnormal arterial vessels in all placentas correlated significantly with the resistance index. This study provides an anatomical basis for the elevated resistance to blood flow in placentas from growth-retarded fetuses.