Archivum histologicum Japonicum = Nihon soshikigaku kiroku最新文献

The transitional zone between the myelinated and the terminal portions of nerve fibers was electron microscopically investigated in the cerebellar cortex of normal rats. A noteworthy finding in the present study is the existence of a "heminode" consisting of the myelinated and non-myelinated portions, as demonstrated within a single section. The heminode seems to be a characteristic structure in the granular layer of the rat cerebellar cortex.

Nervous elements in the periodontal ligament of the monkey, Macaca fuscata were investigated by means of immunohistochemistry for neurofilament protein (NFP) and S-100 protein. Thick nerve bundles with NFP-immunoreactivity entered the periodontal ligament through slits at the bottom of the alveolar socket, whereas thinner bundles, also NFP-immunoreactive, penetrated the ligament from the lateral wall of the alveolar socket. The NFP-immunopositive nerve fibers were densely distributed around the root apex in both incisors and molars. In the upper incisors, another dense distribution of NFP-positive nerves was found in the apical half of the lingual periodontal ligament and in the coronal half of the labial periodontal ligament. The periodontal nerve fibers in the incisors ramified in a dendritic fashion, terminating as free nerve endings within the periodontal ligament. Immunostaining for S-100 protein demonstrated the Schwann sheaths of nerves which showed the same distribution pattern as that of the NFP-immunopositive fibers in the periodontal ligament of the incisors. In molars, immunostaining for NFP and S-100 showed that nerves were numerous in the apical region of the periodontal ligament. However, NFP-immunopositive nerves were fewer than the S-100-positive nervous elements in the apical region in molars. This discrepancy suggests the presence of NFP-immunonegative nerves. Immunostaining for S-100 is thus useful for demonstration of neural elements in the periodontal ligament of molars. The S-100-immunoreactive neural elements in the periodontal ligament were more numerous in incisors than in molars. In addition to the free nerve endings, a small population of coiled nerve endings was observed in the periodontal ligament of molars. Most of the nerve fibers and cell bodies in the trigeminal ganglion showed NFP-immunoreactivity, whereas all in the mesencephalic nucleus of the trigeminal nerve were negative in NFP-reaction. This finding suggests that the periodontal ligament of molars receives a dual innervation from the trigeminal ganglion and mesencephalic nucleus.

Both simple and coiled simple encapsulated sensory corpuscles in the fungiform papillae of primate tongues were examined by light and electron microscopy. These were found to be composed of discoid axon terminals, with cytoplasmic lamellae of lamellar cells surrounding them. The axon terminals were characterized by the presence of distinct finger-like projections extending beyond the corpuscular basal lamina to make contact with collagen fibers, as well as numerous mitochondria, clear vesicles and a few dense-core vesicles in the axoplasm. The cytoplasmic lamellae of lamellar cells showed a number of caveolae on the plasma membrane. Further, desmosome-like contacts were found between adjacent lamellae and between the axon and the innermost lamella.

During the course of the studies on non-traumatized Pacinian corpuscles from normal human adults, we have frequently encountered corpuscles which have an 'apparently multiple' innervation in both light and electron microscopic preparations. On closer inspection of serial sections for both light and electron microscopy, these 'apparently multiple' axon terminals have been found in fact to be branches of the main central axon within the inner core of the corpuscle. Sprouting occurred at the trunk or at the extreme tip of the main axon, and such sprouts extended in various directions from the central axon throughout the inner core, producing tortuous and complex patterns of this 'multiple' innervation. These axonal sprouts do not have separate inner cores separated from one another, but rather are embedded in a common inner core. The presence of a common inner core thus differentiates normal axonal sprouts from the experimentally or pathologically produced multiple innervation that results form regeneration of axons in a previously denervated corpuscle. We conclude that the inner core of Pacinian corpuscles is a unique micro-environment promoting sprouting of sensory axon in the normal human adult as well as juvenile Pacinian corpuscles.

Studies on the marginal zone and colloid of the pituitary cleft in pituitaries of rats aged 2 to 88 days were performed by light and electron microscopy. From 10 days of age the intermediate lobe could be divided into two parts, i.e., the marginal layer and the intermediate lobe proper. The former part consisted of agranular cells facing the cleft; the latter part comprised granular cells stained with PAS-lead hematoxylin. In addition, the former part was separated from the latter by a basal lamina. In 2 and 6-day-old animals, however, there was neither a rising of the marginal layer nor an occurrence of the basal lamina, although the agranular cells and the granular cells could be distinguished in the intermediate lobe. Accordingly, it appears that the marginal layer of the intermediate lobe beings to occur after 6 days of age. The PAS reactivity of the colloid in the pituitary cleft was generally weakly positive up to 20 days of age, and then from 26 days onward the reactivity became stronger, being strongly positive in 74 and 88-day-old rats. Consequently, it is suggested that the PAS positive substances begin to be stored in the cleft after birth and increase with the advance of age.

The fine structure and distribution of the epithelial cells of the airway in the rat were studied continuously from the trachea to terminal bronchioles by scanning electron microscopy (SEM). The airway could be divided into three different regions according to cell population: 1) the trachea and extrapulmonary bronchi; 2) intrapulmonary bronchi (larger than 500 microns in caliber); and 3) bronchioles (smaller than 500 microns in caliber). From their surface structures, the epithelial cells could be classified into ciliated and non-ciliated cells, the latter including brush cells, Clara cells and other non-ciliated (secretory) cells. 1. Ciliated cells. The cilia are longer, thicker and more numerous in the trachea; they decrease in length, thickness and number toward the periphery. 2. Brush cells. They possess thin microvilli (0.2 micron in thickness) in the trachea and extrapulmonary bronchi, with a rounded end. In the bronchioles they possess thick microvilli (0.3 micron in thickness) abruptly ending in a right angle edge. The brush cells are distributed sparsely but rather uniformly, and apt to be grouped in two or more cells. 3. Clara cells. Their apical cytoplasm shows a domed or papillary swelling and possesses a few microvilli. The Clara cells are distributed in the bronchioles and can already be found some distance proximal to the bronchial furcations into bronchioles. 4. Other non-ciliated (secretory) cells. Their apical cytoplasm seems to contain secretory granules immediately beneath the cell surface. They often gather in groups in the trachea and extrapulmonary bronchi, tending to form large areas corresponding to sites supported by tracheal or bronchial cartilage. There were found several orifices in tracheal or bronchial glands whose long axes paralleled the tracheal or bronchial axes. Dome-shaped elevations sometimes appear near the branching points of the intrapulmonary bronchi. There were regarded as bronchus-associated lymphoid tissue (BALT).

Casts of blood vessels in the ovaries of the female rat, pig and monkey were made with methacrylate, dissected out under a dissecting microscope and observed in a scanning electron microscope (SEM). The ovarian arteries and their branches were characterized by the presence of a spiral configuration. The spiral course of the arteries, however, varied greatly in detail among the different species. The arteries in the pig and monkey ovaries had tightly spiraling configurations, while there was only an image suggestive of a spiral in the rat ovarian arteries. The former species showed a rich plexus of the spiral arteries in the hilus and medulla of the organ. Their branches straightened at the transitional region between the medulla and cortex but again showed spiral configurations in the cortex. Further, the arterial branches supplying the growing and mature follicles showed a much more marked extent to the spiral configurations as compared with those of the corpus luteum. In this paper morphological findings shall be discussed in correlation with their physiological implications.

The secretory activity of surface mucous cells was quantitatively studied in the mouse stomach under three different dietary conditions: ad libitum feeding, fasting for 15 hrs, and refeeding 1 hr after 15-hrs fast. Surface mucous cells were classified into isthmus cells, foveolar cells, surface cells and degenerating cells according to stage of maturation. The number of exocytosis and cytoplasmic granules was calculated in unit length of the apical plasmalemma for cells in each stage. Foveolar and surface cells in fasted animals manifested higher exocytotic activity than the other two groups (P less than 0.01). This suggests that physical and chemical stimuli of the gastric content may greatly affect the secretory activity of the cell. Although the number of cytoplasmic mucous granules proved largest in the upper part of the foveola and less at the mucosal surface under any dietary condition, exocytotic activity did not differ significantly between the foveolar cells and surface cells. Degenerating cells very actively discharged mucus, regardless of dietary condition. It is reasonable to postulate that the cells secrete mucus in order to cover the surface and protect the mucosa from damage during degeneration.

The esophageal epithelium of the adult salamander, Hynobius nebulosus, was studied by histochemistry, including periodic acid-Shiff (PAS), alcian blue both at pH 2.5 and pH 1.0, and alcian blue (pH 2.5)-PAS with or without neuraminidase-digestion, and scanning and transmission electron microscopy. The epithelium was columnar in type, comprising partly pseudostratified and partly two-layered architecture; it consisted mainly of ciliated cells, goblet cells, and basal cells. The ciliated cells consisted of two types, light and dark: both types, especially the latter, frequently contained numerous small mucous granules in their apical portion. Ciliated-mucous cells were also occasionally present. Immature ciliated cells were frequently found. Goblet cells were divided into two types: Type I cells possessed electron lucent mucous granules, which frequently contained dense specific inclusions, and frequently bulged into the lumen; Type II cells had moderately electron-dense mucous granules with no inclusions and a conical apex which did not exceed the level of the lumen. The Type I cells were closely distributed throughout the esophagus, while the Type II were mainly dispersed in the cranial portion, remarkably decreasing in the caudal portion. Correlated histochemical and electron microscopic observations suggested that, in the Type I cell, mucous granules contain acid mucosubstances, while in the Type II, they possess neutral mucosubstances, and that in the Type I cell mucous granules consist of sialic acid-containing glycoproteins and their swollen portions are more highly sulfated than the non-swollen ones.