Pierre Drochmans

Electron microscope study of neurosecretory cells in Phasmidae

Abstract The neurosecretory cells, extensively studied in Vertebrates, have been examined with electron microscopy in Phasmidae. In the different types of nerve cells examined, a characteristic association of multilayered Golgi membranes with ergastoplasmic elements and mitochondria has been observed. In the neurosecretory cells at different stages of secreting activity, the same Golgi-ergastoplasm-mitochondria association has been found and tentatively related to the neurosecretion process. These electron microscope observations are in agreement with the previous histochemical findings, which suggest a close relation between basophilia and osmiophilic structures of the cytoplasm and the neurosecretion. The submicroscopic neurosecretory granules, aggregated in clusters, constitute the granules observed by light microscopy. They appear under two types, the “rough” and the “smooth” granules.

Ultrastructural aspects of muscle and nerve in Werdnig-Hoffmann disease.

SummaryThe authors describe in biopsies from 6 cases of Werdnig-Hoffmann disease, including 2 of the more benign type, the ultrastructural typical aspects of denervation. They compare their findings with those of other workers. The striking points are the great variation in the diameter of the muscle fibres and the myofibrils, the disorganisation of the myofibrils, the sarcomeres and the filaments, with persistance of the relations between thick and thin filaments at various levels, the modifications of the Z-band and the triads in chains. The folds and the basement membrane are examined. Centrioles are present in a muscle fibre and in a satellite. Glycogen is very abundant. The nerves seem normal but some Schwann cells contain π granules which are not observed usually at the age of the patient. The end plates and a muscle spindle are normal.

ELECTRON MICROSCOPY AND PHOSPHORYLASE REACTIONS

In this paper, the limitations of electron microscopic techniques, as used for the study of molecular and macro molecular structures of the glycogen type, are defined. Different aspects of glycogen, as isolated from different tissues, were compared and examined ultrastructurally. The in vitro synthesis of glycogen and the changes in its structure, which are produced by enzymatically attaching additional glucose units to the particles, are discussed. Studies of the ultrastructural localization of the enzymes bound to the particles and the eventual role played by the membranes are described. It is concluded that on the membranes of the sarcoplasmic reticulum of the striated muscle a multi enzyme complex exists that consists of phosphorylase phosphorylase kinase and the primer. (Nizze - Rostock)