Archivum histologicum Japonicum = Nihon soshikigaku kiroku最新文献

In order to study the three-dimensional architecture of the cytoskeletal system and its functional properties in the secretory cell, the anterior pituitaries of rats and mice were examined by the quick-freezing deep-etching method. The cytoplasm of the anterior pituitary cell is occupied by networks of several kinds of fine filaments. For convenience, the filaments which terminate at cytoorganelles, secretory granules, and plasma membrane were classified into three types. The filaments running away from the complicated networks of fine filaments terminate on the outer surface of the membrane of the cytoorganelles, secretory granules, and small vesicles and on the inner surface of the plasma membrane. These filaments, 4-10 nm in diameter, were termed associating filaments by us. There are direct connections by filaments between adjacent cytoorganelles, or between the cytoorganelle and secretory granule, or between the secretory granule and plasma membrane. These filaments are also 4-10 nm in diameter, and were termed connecting filaments by us. Short filaments, 3-8 nm in diameter, link directly at right angles the opposite membranes crossing over the cisterna of the nuclear envelope, of the rough endoplasmic reticulum, of the Golgi apparatus, and the intramitochondrial space and also the intercellular space. We named these linking filaments. These findings strongly suggest that these filaments are essential elements for supporting, maintaining and organizing the shape and location of all the cytoorganelles in the cell, and that they vary according to cellular function. The limiting membrane of the secretory granule is bound to the associating filaments and connecting filaments, running radially and at times connecting to the microtubules or plasma membrane. These filaments and microtubules may play a role in the organization and transport of secretory granules toward the plasma membrane.

Organized mechanoreceptors in mucosae and vermilion borders of rat lower lips were studied by light and electron microscopy. Cholinesterase histochemistry was applied to whole-mount preparations of mucosae for the light and electron microscopic identification of mechanoreceptors. Three types of lamellated corpuscles (a simple corpuscle; a coiled, simple corpuscle; and a Meissner-like corpuscle), and a unique, organized, bush-like assembly of free nerve terminals were identified. The simple corpuscles were found exclusively in the vestibular mucosa facing the incisor teeth. In contrast, bush-like endings were confined to the vestibular mucosa and to the lateral, eminent mucosa that faced the diastema. Furthermore, coiled simple corpuscles and Meissner-like corpuscles were localized in the boundary zone between the vestibular and lateral eminent mucosae and in the vermilion border. From a functional viewpoint, it is of interest that different areas of the rat lip contain different morphological patterns of mechanoreceptors.

The distribution of vasoactive intestinal polypeptide (VIP), gastrin-releasing peptide (GRP)/bombesin, somatostatin, vasopressin, neuropeptide Y (NPY) and serotonin was examined immunohistochemically in the suprachiasmatic nucleus (SCN) of male rats genetically deficient for vasopressin (Brattleboro strain). VIP-containing neurons and their varicose fibers were preferentially distributed in large numbers in the ventromedial part of the SCN. GRP/bombesin-containing neurons and their fibers were also gathered in the ventral part of the SCN, particularly in the ventromedial region of the nucleus. Somatostatin-containing neurons and their fibers were prominent in the rostral and middle portions of the SCN, where the highest concentration of immunoreactivity was restricted in their ventromedial part. No vasopressin-immunoreactivity was found at all throughout the SCN. Profuse NPY-containing varicose fibers were observed in the ventrolateral part of the SCN, but no immunoreactive neurons were distributed in this nuclear region. Serotonergic fibers showed a topographic arrangement in the SCN: a serotonin-immunoreactive nerve plexus was predominantly distributed in the ventrolateral part. These findings indicate that the SCN of Brattleboro rats is composed of distinct subdivisions of immunoreactive cell bodies and fibers. The distribution of the five peptides and indoleamine within the SCN in the Brattleboro strain was compared with that in normal Long-Evans rats. Furthermore, both strains of rats were exogenously administered with arginine-vasopressin, but no conspicuous difference in the regional patterns of immunoreactivity was detected. The possible role of vasopressin in the SCN is discussed.

Intra-arterially injected low viscosity methacrylate filled the lymphatic system in the muscularis externa of the young rat. Scanning electron microscopy of the corrosion casts revealed that between the inner and outer muscular coat there was a lymphatic network made up of polygonal meshes. The initial lymphatics, about 15 micron diameter drained into the thicker lymphatics, about 20-80 micron diameter. These lymphatics ran along the muscular fibers of either inner or outer layers and formed polygonal (most often rectangular) meshes. The casts of the thicker lymphatics possessed notches indicative of valve locations. The myenteric nervous plexus was also replicated between the inner and outer muscular coats. The plexus consisted of flat astral structures with primary and secondary, and occasionally, tertiary, processes which interconnected with neighboring ones. It is suggested that the enteric neurons are confined in an interconnected channel system.

The distribution of proliferative cells and maturation of epithelial cells were studied in the pyloric mucosa of developing mice by 3H-thymidine autoradiography, carbohydrate histochemistry and electron microscopy. The formation of the gastric foveola and pyloric gland were seen to begin as an invagination in the epithelial surface and/or the formation of intraepithelial cavity on day 13 of gestation (day E13). Surface mucous cells and pylorocytes were first identified on day E16 by carbohydrate staining as well as by their fine structure. Both types of cells rapidly acquired abundant membranous organelles and secretory granules within the first postnatal day, maturing in fine structure by day 28. Proliferative cells were distributed over the epithelium by day E15, while they were rarely found at the mucosal surface after day E16. Concomitantly with the elongation of foveolae and glands during postnatal development, the proliferative capability of surface mucous cells diminished from the foveolae and that of pylorocytes from the glands, respectively; the generative zone was restricted to the isthmus by day 21, as in the adult animal. These results reveal that the histogenesis of the mouse pyloric mucosa is accomplished by the end of the weaning period.

Ferric chloride, when boiled with ammonium thiocyanate, ammonia and cacodylic acid, is converted into a fine anionic iron colloid which consists of 1-1.5 nm electron dense granules and gives a distinct Prussian blue reaction. This colloid allows light and electron microscopic detection of ionized cationic sites in tissues at a pH range of 4.0-9.0. Light and electron micrographs of the rat kidney stained with this colloid are demonstrated. These micrographs indicate that the foot processes of glomerular podocytes and the brush border of the proximal convoluted tubule contain positively-charged groups in their intracellular matrices, and that the foot process plasma membrane fronting the Bowman's capsular space has positively-charged groups. The latter finding, together with our previous study (Murakami et al., 1986), suggests the co-existence of cationic and anionic sites on this foot process surface.

This study was conducted to examine follicle growth and intra-ovarian oocyte release in rabbit ovaries influenced by a local application of prostaglandin formation inhibitors. While five rabbits remained as unstimulated controls, twenty-seven mature rabbits were hyperstimulated by pure follicle stimulating hormone (FSH) followed by human chorionic gonadotropin (hCG) at time 0. At the same time, 1 mg lonazolac (lonazolac group), indomethacin (indomethacin group) or saline (so-called gonadotrophic stimulated controls) was applied into the vagina of each group. Both ovaries of each animal were evaluated morphometrically at 15, 20, 28 and 48 hr after hCG. The absolute numbers of smaller-sized preantral follicles were always higher in the gonadotrophic stimulated controls than in the unstimulated controls, the lonazolac, or the indomethacin group. The numbers of larger-sized preantral and antral follicles showed no differences. Unlike the gonadotrophic stimulated controls and the lonazolac group, the indomethacin group displayed an increase in its mature structures (large-sized antral and preovulatory follicles, follicle and luteinized cysts) from 20 to 28 hr after hCG. Call-Exner bodies underwent pseudomucification in preovulatory follicles. The absolute numbers of Call-Exner bodies were augmented by indomethacin. Maturation division of oocytes began to decrease in all three treated groups between 15 and 20 hr post hCG, but the height of intra-ovarian oocyte release (IOR) appeared at 28 hr. This coincided with a striking thrombus formation. It is assumed that: 1) lonazolac and indomethacin inhibit early development of proliferating follicles; 2) lonazolac and indomethacin have no effects on the maturation division of the oocyte and of IOR; 3) IOR extends over a longer period after ovulation induction in contrast to the maturation division of the oocyte; and 4) thrombus formation is related to IOR.

The endoneurium of the mouse sciatic nerve was studied by scanning and transmission electron microscopy to elucidate their three-dimensional architecture. The endoneurium consisted of collagen fibrils, and occasional fibroblasts and blood vessels. Collagen fibrils surrounded individual nerve fibers, forming two distinct layers of connective tissue sheath: the outer one was composed of bundles of longitudinally oriented collagen fibrils and the inner one was of a delicate network of interwoven thin collagen fibrils. These outer and inner layers of collagen fibrils correspond to the two fibrous sheaths known as the sheath of Key and Retzius and the sheath of Plenk and Laidlaw, respectively, revealed on nerve fibers by silver impregnation. Some of the finest collagen fibrils forming the inner network are closely attached to the basal lamina of Schwann cells, suggesting that these fibrils are concerned with the connection between the basal lamina and the inner collagen network. These two layers of collagen fibrils were found on all the nerve fibers, suggesting that they represent a general structure ensheathing the peripheral nerve fibers. Although these layers occur also on unmyelinated nerves, they are most developed on the largest myelinated fibers.

Osteoclasts of rat mandibulars were observed under the transmission electron microscope with the aim of understanding the three-dimensional structure of the ruffled border. After observation, the same block was remounted to obtain sections of the same osteoclasts at right angles to the first sectioning plane. The structure of the ruffled border of osteoclasts was observed in the two perpendicular directions. The ruffled border of osteoclasts was found to consist of two areas: one being composed of finger-like processes and the other, of plate-like processes. The distribution of the two areas of processes in the ruffled border did not show any apparent regularity. Not all processes continued to the cell body; some processes (stem processes) did while others were interwoven branches of the stem processes. The finger-like processes were long and rod-shaped and a few of them branched directly from the stem processes. The plate-like processes were long and belt-like and showed complicated branching from the stem processes; some of these were possibly the long belt-like processes that were complicatedly folded up to make many secondary plates; they are arranged parallel to each other in a given area. The relationship between the structure and function of the ruffled border is discussed.

The immunohistochemical localization of inhibin in porcine and bovine ovaries was studied, using monoclonal antibodies to bovine follicular fluid 32K inhibin (bFF 32K inhibin) and a polyclonal antiserum to porcine follicular fluid 32K inhibin (pFF 32K inhibin). In order to obtain a precise immunohistochemical staining, various fixations were tested with an immunoblotting procedure. Acetone fixation followed by celloidin embedding proved to be most appropriate for the immunohistochemical study of inhibin. A consistent pattern emerged in all sections prepared from porcine and bovine ovaries. Granulosa cells were specifically stained by the antibodies, and especially the cells constituting the inner layer were more intensely stained than the cells close to the theca.