摘要:

The trigeminal nerve has three motor roots and one sensory root in the cat. One of the motor roots can be divided into two bundles: the larger and the smaller. These motor roots form the common root with the sensory root at the exit from the pons, sometimes being separated partially by the subarachnoidal space between the medial and the ventral part of the common root. The mesencephalic root fibers are observed numerously in all the motor roots. Some degenerated fibers are observed in the sensory root. The transitional zone of the trigeminal nerve root between central and peripheral nervous system is occupied by interlocking processes of the fibrous astrocyte.

ISSN:1422-6405    

DOI:10.1159/000145967

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

The administration of colchicine disrupts the normal organization of the Golgi complex and blocks the secretion of collagen precursors in periodontal ligament fibroblasts of the mouse. The fate of the unsecreted collagen precursors contained in Golgi-derived saccules and newly formed dense bodies was followed by electron microscopy. A progressive condensation of saccule content along with phase separation of electron-dense and electron-lucent material was observed. Fusion of saccules with dense secretory bodies gave rise to larger inclusions (zebra bodies; ZB) filled with a combination of electron-dense and electron-lucent material. In some ZB, these materials appeared to polymerize into fibrillar units. The fibrillar units stained with silver methenamine like normal collagenous fibrils. These results suggest that unsecreted collagen precursors accumulate in vesicular compartments within which partial polymerization can occur. This finding may explain some reports of intracellular collagenous fibrils in fibroblasts of pathologically altered connective tissues.

ISSN:1422-6405    

DOI:10.1159/000145968

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

In silver eels the arteries supplying the pectoral girdles and fins, arise from a common trunk which branches off from the dorsal aspect of the dorsal aorta, while the origin of this trunk is found at the ventral aspect of the aorta in the leptocephalus larva. The rearrangement of the origin of this trunk is mainly accomplished during metamorphosis, and is related to the rearrangement of the junction of the epibranchial arteries and the aorta. The processes of remodelling the wall of the vessels involved in these rearrangements are discussed against the background of data on similar remodelling, accompanying the rearrangement of arterial junctions during the development of higher vertebrates.

ISSN:1422-6405    

DOI:10.1159/000145969

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

Human fetal primary tooth germs in the cap stage were fixed with a glutaraldehyde-formaldehyde mixture, and formative processes of tight and gap junctions of the inner enamel epithelium and preameloblasts were examined by means of freeze-fracture replication. Chains of small clusters of particles on the plasma membrane P-face of the inner enamel epithelium and preameloblasts were the initial sign of tight junction formation. After arranging themselves in discontinuous, linear arrays in association with preexisting or forming gap junctions, these particles later began revealing smooth, continuous tight junctional strands on the plasma membrane P-face and corresponding shallow grooves of a similar pattern on the E-face. Although they exhibited evident meshwork structures of various extents at both the proximal and distal ends of cell bodies, they formed no zonulae occludentes. Small assemblies of particles resembling gap junctions were noted at points of cross linkage of tight junctional strands; but large, mature gap junctions no longer continued into the tight junction meshwork structure. Gap junctions first appeared as very small particle clusters on the plasma membrane P-face of the inner enamel epithelium. Later two types of gap junctions were recognized: one consisted of quite densely aggregated particles with occasional particle-free areas, and the other consisted of relatively loosely aggregated particles with particle-free areas and aisles. Gap junction maturation seemed to consist in an increase of particle numbers. Fusion of gap junctions in the forming stage too was recognized. The results of this investigation suggest that, from an early stage in their development, human fetal ameloblasts possess highly differentiated cell-to-cell interrelations.

ISSN:1422-6405    

DOI:10.1159/000145970

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

Calcium distribution in pancreatic B cells was studied, with the aid of the pyroantimonate technique, at different times of glucose-induced secretory activity in the perfused rat pancreas. Specificity of the pyroantimonate precipitates for calcium was assessed by EGTA cross-incubation. Quantitative studies for these calcium pyroantimonate precipitates were performed by a morphometrictechnique. Pyroantimonate precipitates within the B cell show both time and glucose dependence. At any time-point studied, in the nucleus as well as in other organelles, they were more numerous when glucose was increased in the medium from 3.3 to 16.6 mmol/l. The total number of nuclear calcium pyroantimonate precipitates rose sharply at the time corresponding to the refractory period, falling after that to almost the number found at the prestimulatory period. Otherwise, glucose significantly modifies the temporal distribution of precipitates bound to euchromatin, heterochromatin and perichromatin. These changes in nuclear calcium pyroantimonate precipitates during different periods of B cell secretory activity may indicate an active role of the cation in some nuclear regulatory function during glucose-induced release of insulin.

ISSN:1422-6405    

DOI:10.1159/000145971

出版商:S. Karger AG    

年代:1985

数据来源: Karger

摘要:

The three-dimensional and surface structures of the simple conical papillae of the rat tongue have been demonstrated with scanning electron microscopy. The papillary projection was organized into the anterior, posterior and central core cell populations, whereas the basal region of the papilla which consisted of circularly arranged cells showed no differentiation into three autonomic cell populations. It is considered that the anterior and posterior cell populations around the central core tend to be mutually attached at the bilateral sides, and that the posterior and core cell contacts are rather close than the anterior one. The anterior papillary cells showed relatively smooth surface with little micropits and without micro ridges. The reticular microridges on the basal cell surface of the posterior papillary cells appear to later develop the micropits and linear microridges on the tip cell surface. These suggest that the anterior cell surface is more highly keratinized than the posterior one. The microridges or micropits on the outer cell surface and the microprojections on the inner cell surface organizing filiform papilla are considered to be the structures for the purpose of cell adhesion.

ISSN:1422-6405    

DOI:10.1159/000145972

出版商:S. Karger AG    

年代:1985

数据来源: Karger

ISSN:1422-6405    

DOI:10.1159/000145973

出版商:S. Karger AG    

年代:1985

数据来源: Karger

ISSN:1422-6405    

DOI:10.1159/000145974

出版商:S. Karger AG    

年代:1985

数据来源: Karger

ISSN:1422-6405    

DOI:10.1159/000145975

出版商:S. Karger AG    

年代:1985

数据来源: Karger

ISSN:1422-6405    

DOI:10.1159/000145976

出版商:S. Karger AG    

年代:1985

数据来源: Karger