Marie Elisabeth Stoeckel

A comparative ultrastructural study of the pars tuberalis of various mammals, the chicken and the newt

SummaryThe pars tuberalis of the rat, mouse, garden door mouse, European hamster, cat, cattle, chicken and newt is composed of two main cell types: specific secretory cells and follicular cells. The specific cells are characterized by comparable morphologic features in the investigated species, despite differences in the diameter of the secretory granulated vesicles; the ultrastructural morphology of these cells is different from that of any of the known cell types of the adenohypophysis. The follicular cells are devoid of secretory granules, they do not only line the numerous follicular cavities of the pars tuberalis but may also be found in the periphery of the cell cords (border cells). In addition, gonadotrophic cells are found; they predominate in the distal portion of the pars tuberalis and are definitely activated by castration or hypophysectomy. Experimental interventions on most of the major endocrine systems did not cause any noticeable ultrastructural changes in the specific cells. It appears certain that the pars tuberalis secretes a specific hormone whose function remains to be determined.

Herring Bodies Reexamined: An Ultrastructural Experimental Investigation of the Rat Neural Lobe1,2

In 1970 (a), DELLMANN/RODRIGUEZ gave a detailed account of the ultrastructure of mammalian Herring bodies and subdivided them into three main types. Type I Herring bodies are characterized by the presence of numerous neurosecretory granulated vesicles and a few mitochondria, Type I1 Herring bodies contain many dense lamellar bodies, a very extensive axoplasmic reticulum and only a few neurosecretory granulated vesicles, and Type I11 Herring bodies possess a still more extensive axoplasmic reticulum together with numerous mitochondria and a varying number of neurosecretory granulated vesicles. Based upon these morphologic characteristics it was hypothesized that Type I Herring bodies are nothing else but an accumulation of neurosecretory granulated vesicles, the excess of which is being disposed of through a process of involution in the Type I1 Herring bodies, (in 1970 the term degeneration was used to characterize localized catabolic events which usually do not entail interruption of the axonal continuity: see conclusions) followed by restitutional events in the Type I11 Herring bodies. As the first part of this hypothesis was based upon the observed similarity between the morphologic pictures of degenerating amphibian neurosecretory axons (DELLMANN/RODRIGUEZ, 1970 b) and Type I1 Herring bodies, i t was felt that an investigation of degenerating mammalian neurosecretory axons might

Storage of proteins in the rough endoplasmic reticulum of human hepatocytes in a patient with normal blood proteins, on oral contraceptives.

Aspects of protein storage in the rough endoplasmic reticulum of hepatocytes, comparable with those reported in α1-antitrypsine (AAT) deficiency, have been observed in the course of jaundice in a woman presenting no evident abnormality in AAT or other blood proteins. In light microscopy, most hepatocytes contained characteristic globular inclusions but they were PAS negative and did not react with anti-AAT antibodies. This storage of protein ceased at the time the jaundice disappeared. Prolonged treatment with high doses of contraceptive steroids may have been involved in this peculiar reaction of the hepatocytes.

Modifications in the Sarcoplasmic Reticulum and Subcellular Calcium Distribution in Skeletal Muscle in a Case of Westphal's Disease (Hypokalemic Periodic Paralysis)

In a case of hypokalemic periodic paralysis with characteristic alterations of the sarcoplasmic reticulum (SR) in the skeletal muscle, subcellular calcium re-partition, as revealed with the pyroantimonate technique, appears disturbed during paralysis. Pyroantimonate precipitates, normally concentrated in the terminal cisternae of the SR, were localized in the T tubules, whereas the terminal cisternae appeared empty. The increase (about 14%) in muscular calcium during paralysis may result from the accumulation of calcium in the extracellular compartment (T tubules). Defects in calcium uptake and storage by the SR may be. involved in the pathogenesis of the periodic paralysis syndrome.

Togavirus-like particles in renal epithelium of patients with systemic lupus erythematosus

Virus-like particles, about 45 nm in diameter, were present in renal epithelium (tubules and podocytes) of 12 patients with confirmed systemic lupus erythematosus (SLE) and in 2 patients with probable SLE. They were not detected in renal biopsies from non-SLE patients. Morphologically, they suggest togavirus-like particles.