Archivum histologicum Japonicum = Nihon soshikigaku kiroku最新文献

The occurrence and fine structure of the autonomic groundplexus in the lamina propria mucosae of the guinea-pig small intestine were studied by scanning electron microscopy after removing connective tissue elements by maceration in hydrochloric acid. Transmission electron microscopy was also performed to investigate the fine structure of the neuronal and glial elements in the autonomic groundplexus. Nerve fasciculi consisting of neuronal processes and enteroglial cell sheaths formed a three-dimensional network intercalated between blood and lymph vessels. Processes of enteric neurons ran within the enteroglial cell framework. No blind ends of nerve fasciculi were found. Terminal varicosities of neuronal processes were frequently exposed on the surface of the nerve fasciculi. The locations of these naked varicosities may represent the sites of interaction between the enteric neurons and their target tissues.

Connective tissue papillae underlying epithelial cell layers of the lingual papillae of newborn mongrel dogs were exposed by long term hydrochloric acid treatment and observed by scanning electron microscopy. Each of the filiform papillae of ovoid shape (100-130 microns in diameter) contained a connective tissue papilla representing a smaller elliptical protrusion (90-100 microns in length, 70-80 microns in width). Its overview showed a horse-shoe shaped, opening anteriorly. Its posterior curvature projected a conical node with a rounded apex. Each of the fungiform papillae (150 microns in diameter) contained a connective tissue papilla of rounded shape (100 microns in diameter) whose upper surface was facetted with several slight depressions. The entire surface of the connective tissue papillae was found to be covered by networks of collagenous fibers of varying thickness, running in various directions. The basal surface of the epithelium revealed regularly distributed round holes that corresponded to the connective tissue papillae. In the filiform papillae, a small elliptical bulge was seen on the anterior side of each hole. Light microscope observation indicated that the anterior column of the filiform papillae contained a granular layer with moderate keratohyaline granules, whereas the posterior column did not show such a granular layer.

Cryptorchid surgery to move the testis and epididymis to the abdomen was performed in mice of 60 days of age; one week later the mice were subjected to further surgery to reposition the organs in the scrotum. The mice were sacrificed at 1 week intervals until 11 weeks after the initial operation. After the first operation, spermatozoa in the epididymal duct rapidly disappeared and were almost absent until the 4th week. Then spermatozoa appeared again, increased, and reached normal numbers by 10 weeks. With the disappearance of the spermatozoa, a PAS-positive material, which is believed to be secreted in the middle part of the head of the epididymal duct (ABE et al., 1982), was accumulated in the epididymal duct in the body and tail of the epididymis, and PAS-positive inclusions appeared in the principal cells of the duct in the body 2 weeks after the first operation. The inclusions developed in size and number during the aspermia period, then decreased in number with the reappearance of spermatozoa from the 5th week to ultimately disappear by 10 weeks after the first operation. We have previously demonstrated that such inclusions appear also after efferent duct ligation, which interrupts the flow of spermatozoa and testicular fluid into the epididymal duct (ABE et al., 1982). Both present and previous findings indicate that the appearance of PAS-positive inclusions depends on the absence of spermatozoa in the epididymal duct irrespective of the presence of the testicular fluid in the duct. It is suggested that the PAS-positive material is utilized by spermatozoa and, in the absence of spermatozoa, is accumulated in the lumen and ingested by the principal cells of the epididymal duct in the body of the epididymis.

The hepatic sinusoids of the soft-shelled turtle (Amyda japonica) were examined by transmission electron microscopy. The sinusoidal wall was composed of endothelial cells, Kupffer cells and Ito cells. The basal surface of the hepatocyte facing the Disse's space was covered by a continuous basal lamina. In addition to the Ito cells, the Disse's space contains a considerable number of smooth muscle cells. Many of these were distributed sporadically, while others appeared as a sphincter circling the sinusoid. The smooth muscle cells in the Disse's space showed the following features: 1) The nucleus was located eccentrically near one end of the cell. 2) The surface vesicles and pits, mitochondria and dense patches along the myofilament bundles were all sparse as compared with those known from mammalian smooth muscle cells. 3) Cytoplasmic processes or ruffles were protruded into the Disse's space. 4) A weak basal lamina could be recognized. Sinusoidal endothelial cells were characterized by many large electron lucent lysosomes in their perikaryon and by small fenestrae in their attenuated cytoplasm. Ito cells sending out several cytoplasmic processes, possessed a single large lipid droplet on one side of the nucleus. A single cilium budding from the distal centriole into the Disse's space was found in an Ito cell. Extrasinusoidal macrophages were considerably numerous in the soft-shelled turtle liver. Some of the macrophages were apparently migrating into the sinusoid, there to presumably transform into the Kupffer cells.

The three-dimensional vascular distribution and the vascular-parenchymal relationship in normal guinea pig thymus were studied by light, scanning and transmission electron microscopy. Interlobular arteries arising from one thymic artery entered the thymic parenchyma where they branched into arterioles and then formed capillary networks in the cortex and in the medulla. Most cortical capillaries drained to the surface via perpendicular venules which merged into the subcapsular veins. Some vessels of the inner cortex, however, returned blood to the postcapillary venules (PCVs) at the cortico-medullary junction and in the medulla. The vascular supply of the guinea pig thymus is thus characterized by a dual circulation in which venous blood drains either via a subcapsular or via a cortico-medullary route. The endothelium of the postcapillary venule (PCV) was flat and often contained migrating lymphocytes. These venules were surrounded by a perivascular space (PVS) which separated the vessel from the parenchyma and which contained many lymphocytes. This PVS was not lined by cells but was delimited on one side by the abluminal surface of the venular endothelium and on the other side by a thin, sheet-like layer formed by cytoplasmic processes of epithelial reticular cells. This epithelial sheet was not continuous, as there were frequent interruptions or gaps where the PVS communicated directly with the intercellular mesh of the thymic parenchyma. The PVS did not form a continuous longitudinal channel but was interrupted by epithelial trabeculae. Some macrophages and a few plasma cells were seen in the parenchyma near the PVS. These findings suggest that the PCV and the PVS in the thymus may function as pathways for the migration of lymphocytes into or out of the blood circulation.

Atria from dystrophic and non-dystrophic mice were examined by light and electron microscopy. Particular attention was paid to the granularity of the specific atrial granules and the development of the Golgi apparatus. At the light microscopic level, both a decrease in number and degenerative changes were recognized in the atrial cardiocytes, which were intercalated by increased connective and adipose tissues. At the electron microscopic level, the dystrophic atrial cardiocytes showed a variety of degenerative changes and a decreased number of granules; the impaired development of the Golgi apparatuses were noticed. A quantitative analysis revealed that the number of the granules per unit area in dystrophic cardiocytes was significantly smaller in both the right and left atria, and that the relative area occupied by the Golgi fields of the dystrophic was significantly smaller in the right atrium than in non-dystrophic controls. These findings indicate that the synthesis of atrial natriuretic polypeptide (ANP) is inhibited in dystrophic mice. It is suggested that the water and electrolyte imbalance known in dystrophic cases can be accounted for by the impaired secretion of ANP in the heart.

Fat-storing cells in the liver of an adult Schneider's skink were investigated by means of transmission electron microscopy. The fat-storing cells were localized in the perisinusoidal space or in the hepatic "recessus". They revealed a single cilium originating from one of the paired centrioles and projecting into the perisinusoidal space. The functional significance of a single cilium in the fat-storing cell is still unclear.

The distribution of carbonic anhydrase (CA) activity was studied by electron microscopic histochemistry in rat Pacinian corpuscles, Meissner corpuscles and Merkel cell-neurite complexes using the cobalt bicarbonate method. The distribution of CA activity in these axon terminals was compared to the activity in sciatic nerve axons. An intense enzymatic CA activity was demonstrated in axon terminals of both Pacinian and Meissner corpuscles, while a weak activity was found within the axoplasm of terminals abutting Merkel cells. Some large- and medium-sized axons in sciatic nerves exhibited an intense activity. These findings indicate that large- or medium-diameter sensory axons innervating corpuscular endings have an intense CA activity extending from their somata to their sensory terminals. Axons to Merkel-neurite complexes differ in CA activity from those innervating Meissner and Pacinian corpuscular endings.

Complete casts of the hypophyseal and hypothalamic blood vascular beds of newborn, pubescent, adult and aged rats were produced by infusion of low viscosity methacrylate media, dissected under a binocular light microscope, and observed with a scanning electron microscope. The primary capillary plexus projected capillary loops into the median eminence and infundibular stalk. These loops were composed of anastomosing capillaries, being numerous in the central area of the anterior lip of the median eminence. The well developed long loops received their proper afferent arterioles from the arterial terminals in the primary plexus, and emitted their proper efferent venules continuous with the long portal vessels. The loops in newborn rats were poorly developed, appearing as simple ball-like protrusions of the capillaries of the primary plexus. Many branches of the anterior, middle and accessory middle hypophyseal arteries penetrated the primary plexus, and ascended as infundibular ascending arterioles in the median eminence and infundibular stalk. These infundibular ascending arterioles continued into the capillary bed of the hypothalamus, especially in its basilar and peri-ventricular areas. The subependymal capillary network was fairly independent, and located dorsal to the loops. This network received some of the infundibular ascending arterioles, and emitted infundibular descending venules continuous with the long portal vessels. The subependymal network also received the infundibular descending arterioles from the hypothalamic arteries, and emitted the infundibular ascending venules continuous with the hypothalamic veins. Thus, neither a feedback nor a retrograde portal route from the hypophyseal capillaries to the hypothalamic capillaries was noted. The capillary bed of the pars tuberalis was observed only in the adult and aged rats; it was a very coarse network which was derived from the primary capillary plexus and connected to the secondary capillary plexus.

Rabbits were starved for a week and then allowed to take the standard diet; the animals were sacrificed after 20 or 24 hr. One group of the animals were treated in winter, and the other, in summer. Control animals were fed solid rabbit food ad libitum. In the control rabbits, short rudimentary canaliculi and occasional small-sized pored domes were found in the thicker portions of the endothelial extension. In the animals experimentally treated in winter, well-developed meandering canaliculi with vacuolar expansions and constrictions appeared in the thicker portions and perikaryonal cytoplasm. In addition prominent pored domes were produced. The canaliculi often formed sponge-like networks with openings both to the sinusoid and the Disse's space. The development of the canalicular system and pored domes correlated to an increased blood flow through the sinusoids; this seemed to be induced upon sudden feedings after lengthy starvation. The rabbits subjected to the experimental treatment in summer exhibited no distinct development of the canaliculi and pored domes. This result was ascribed to the inhibited functions of the rabbit liver during this season.