Hideo Isono

Electron microscopic study of the parathyroid gland of the acetazolamide-treated mouse.

Ultrastructural aspects of the parathyroid glands of acetazolamide-treated mice were examined. Many chief cells of the treated mice are deficient in free ribosomes compared with the control mice. Most Golgi complexes are poorly developed and associated with a few prosecretory granules. However, relatively numerous secretory granules are observed in the cytoplasm, and a few secretory granules are present in the peripheral cytoplasm. Large secretory granules (storage granules), homogeneously dense bodies with a low electron density, heterogeneously dense bodies containing osmiophilic substance and/or lipid-like material, multivesicular bodies and lipid droplets have apparently increased in number in many chief cells of the experimental mice. Many transitional forms are recognized between each of the large secretory granules and the bodies mentioned above. These ultrastructural features suggest that parathyroid gland cellular activity is suppressed in response to acetazolamide treatment. In addition, correlations of the occurrence of large secretory granules and various bodies are discussed.

Effects of Starvation on the Ultrastructure of the Mouse Parathyroid Gland

Ultrastructural changes of the parathyroid glands of starved mice were examined. The parathyroid glands of the starved mice showed a decrease in the volume of Golgi complexes and storage granules and an increase in the volume of lipid droplets, and contained more heterogeneously dense bodies and multivesicular bodies compared with that of the control mice. In addition, the volume of mitochondria, cisternae of granular endoplasmic reticulum and secretory granules and the number of prosecretory granules appeared to be decreased compared to those of the control mice. Myelin-like structures were observed in the parathyroid glands of the starved mice. The results of our study provide support for the hypothesis that starvation exerts an inhibitory influence not only on the synthesis but also on release of parathyroid hormone.

Electron microscopic study on the parathyroid gland of the newt Triturus pyrrhogaster (boié) in natural hibernation

The parathyroid gland of newts in natural hibernation was studied by means of the electron microscope. There were two types of epithelial cells in the parenchyma: one type having numerous filaments and a few cell organoids and other inclusions, and the other type containing few filaments and many cell organoids and other inclusions. Cells of the first type rested on a basement membrane bounding the connective tissue and were termed “basal cells.” Cells of the second type were in a suprabasal position and formed the remainder of the parenchyma. These cells were referred to as “suprabasal cells.” The basal cells might be supporting, rather than secretory, cells. In the suprabasal cells, the nature of the dense bodies, vacuolar bodies, and heterogeneously dense, irregularly shaped masses was discussed. It was suggested that the dense and vacuolar bodies may be lysosomal, the irregularly shaped masses may be lipofuscin pigments in nature, and both might be associated with a control mechanism for secretion.

Evidence for penetration of intraperitoneal horseradish peroxidase into vagal preganglionic neural elements.

Intraperitoneal horseradish peroxidase was found to penetrate directly into the vagal preganglionic neural elements. After intraperitoneal administration of horseradish peroxidase, the bilateral dorsal nucleus of vagus nerve was labelled retrogradely with the enzyme. Other regions of medulla oblongata and sacral spinal cord were free from labelling. The significance of these findings was considered in relation to studies of autonomic nerve supply of abdominal viscera using retrograde transport of horseradish peroxidase.

Effects of vagotomy on the ultrastructure of the parathyroid gland of the rabbit

Ultrastructural changes of the parathyroid glands of vagotomized rabbits were examined. Many chief cells at 6, 12, 18 and 24 h after vagotomy are rich in free ribosomes compared to control rabbits. The main changes in the parathyroid glands of rabbits at 12, 18 and 24 h after vagotomy as compared with the control animals are a proliferation of the Golgi complexes, an increased number of secretory granules in the peripheral cytoplasm, and a frequent occurrence of enlarged intercellular spaces containing finely particulate substance. Large secretory granules, heterogeneously dense bodies, multivesicular bodies and lipid droplets apparently decrease in number in many chief cells at 12, 18 and 24 h after the operation. These alterations suggest that synthesis and release of parathyroid hormone are stimulated in many chief cells of the vagotomized rabbits. In addition, correlations of the occurrence of large secretory granules and various bodies are discussed.

Origin of the Water-Clear Cell in the Parathyroid Gland of the Golden Hamster

Water-clear cells and transitional forms between the chief cells and water-clear cells were observed in the parathyroid gland of the golden hamster. Their ultrastructure is described, and the origin of the water-clear cell is discussed.

Origin of Autonomic Nerve Fibers Innervating the Parathyroid Gland in the Rabbit

The cells of origin of nerve fibers innervating the parathyroid gland were studied in the rabbit using the HRP-retrograde transport method. Numerous labeled neurons were observed in the caudal half of the ipsilateral superior cervical ganglion following HRP injection into the parathyroid gland. Furthermore, in the medulla oblongata, labeled neurons were found in the dorsal nucleus of the vagus and many of them were distributed caudal to the level of the obex.

Effects of cadmium on the ultrastructure of the mouse parathyroid gland

Electron-microscopic studies were made on the parathyroid gland of cadmium-treated mice. Most chief cells in treated mice were rich in free ribosomes and secretory granules compared to the control mice. In the parathyroid gland after 3 and 4 weeks of administration of cadmium, interdigitations between adjacent chief cells became more complex than in the control mice. In most chief cells of the parathyroid gland after 2, 3 and 4 weeks of administration of cadmium, the Golgi complexes associated with numerous prosecretory granules were better developed than in the control mice. These ultrastructural appearances suggest that parathyroid gland cellular activity was stimulated in response to cadmium treatment.

A study of the arterial supply of the human acetabulum using a corrosion casting method.

This anatomical study concerns the arterial supply of the human acetabulum. The purpose is to contribute to prevention of postoperative necrosis of the acetabular bone fragment after rotational acetabular osteotomy (RAO). The arterial supply of the acetabulum was determined using a corrosion casting method. The acetabular branch of the obturator artery supplies the acetabulum through the acetabular notch. The pubic branches supply the pelvic surface of the acetabulum. Deep branches of the superior gluteal artery supply the superior region and the inferior gluteal artery supplies the postero‐inferior region. From these results, we recognized that the important artery for achieving successful RAO is the acetabular branch of the obturator artery that supplies the acetabulum through the acetabular notch. Clin. Anat. 10:77–81, 1997

Effects of Hypergravity Environment of the Ultrastructure of the Golden Hamster Parathyroid Gland

The fine structure of the parathyroid glands of golden hamsters exposed to 2, 5 or 10 g environment for 5 h was studied. In the centrifuged hamsters, many secretory granules are located in a peripheral position just beneath the plasma membrane of chief cells, and the Golgi complexes and cisternae of the granular endoplasmic reticulum are significantly increased compared with those of control animals. There are no significant differences between the control and centrifuged animals with regard to secretory granules, large secretory granules, lysosomes, vacuolar bodies and lipid droplets. These findings suggest that the secretory activity of the parathyroid gland may be stimulated in response to hypergravity environment.