The aim of this study was to assess whether the Energy Expenditure Index (EEI), based on heart rate (HR) adjusted for speed, was a clinical indicator of the Oxygen Consumption Index (OCI), oxygen consumption (VO(2)) adjusted for speed, during self-paced walking in children with spastic diplegia cerebral palsy (CP) and children without physical disabilities (ND). Ten children with spastic diplegia CP and 15 children who are ND participated. VO(2) and HR were measured at rest and during self-paced ambulation using an AeroSport KB1-C portable metabolic system, and the EEI and OCI were calculated. A fair to good correlation (r = 0.61) between EEI and OCI was found for children with spastic diplegia CP ambulating at self-paced speeds while only a moderate correlation (r = 0.40) was found for children who are ND. The results suggest that the EEI may be a useful clinical indicator of OCI at self-paced ambulation speeds in children with spastic diplegia CP and warrants further investigation.

Electron micrographs from this study demonstrate several stages in the formation of the nuclear cap and acrosome by the Golgi system. Formation of small vesicles from Golgi membranes, coalescence of these vesicles into the nuclear cap with concomitant fusion of contained granules to form the acrosome, is confirmed. Mitchondria, which at low magnifications appear to be "empty," are shown by high magnification to contain dilated intracristal spaces. In many cases cristae are arranged parallel to the mitochondrial surface.In later spermiogenesis, appearance of the caudal sheath or manchette, proximal centriole, and terminal annulus ("ring centriole") precede formation of the middlepiece and flagellum. The presence of a series of parallel "annulated" membranes has been described. The exact nature of these membranes, which appear to connect with the cisternae of the endoplasmic reticulum, remains to be investigated.

Studies of the ultrastructure of the seminiferous tubule of the Swiss mouse have shown the external limiting membrane to consist of internal and external lamellae enclosing a single layer of flattened cells. Both lamellae contain fibers, probably collagenous, running parallel to the long axis of the tubule. Superficially, a layer of connective tissue cells covers the external lamella. The nucleus of the Sertoli cell is typified by irregularity of size and shape, electron density of the nuclear membrane, and characteristic nucleolus. The cytoplasm contains mitochondria with vesicular cristae, and irregular dense bodies of possible secretory origin. Cytoplasmic processes extend between the germinal cells and in certain areas their surfaces are marked by periodic accumulations of fine granules which present a picture suggestive of desmosomes.Two types of spermatogonia have been noted. One possesses a large spherical nucleus containing finely granular nucleoplasm and scanty cytoplasm. The second is characterized by an ovoidal nucleus containing numerous chromatin clumps and scattered nucleolar fragments. Primary spermatocytes exhibit the intercellular bridges and synaptinemal complexes characteristic of these cells. The spherical nuclei contain densely packed fine granules. The nuclei of secondary spermatocytes often exhibit centrally located clumps of chromatin material. Mitochondria appear vacuolated at low magnifications but high magnification micrographs show them to contain finely membranous cristae.

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