Archivum histologicum Japonicum = Nihon soshikigaku kiroku最新文献

Using injections of horseradish peroxidase (HRP) and the osmium-tannic acid method, megakaryocytic cells in the livers of rat embryos at 12-16 days of gestation were examined for the purpose of classification of the stages of formation of the platelet demarcation membrane. Megakaryoblasts were classified into the following three types according to the formation patterns of the demarcation membrane. The P-type megakaryoblasts showed plate-like membrane invaginations in large localized areas at early stages. The invaginating membrane developed toward the periphery of the nucleus. The L-type megakaryoblasts showed localized labyrinthine membrane invaginations but no definite direction in its development. The T-type megakaryoblasts had tubular invaginations at multiple sites on the plasma membrane. The P- and L-type cells were observed at 12 and 13 days of gestation. The T-type cells were found after the 14th day. In all the types of megakaryoblasts the membrane invagination occurred in the areas making contact with hepatocytes. It was agreed that the cells of the megakaryocytic series in which the demarcation membrane developed contrary to the basic pattern were ordinary promegakaryocytes. The megakaryocytes forming networks of the demarcation membrane dividing into platelet areas were small in cell size. Examination of the patterns of formation of the demarcation membrane proved useful for classifying the megakaryocytic series at each stage of maturation.

Electron microscopy of a neuro-insular complex type II is described in the adult cat. A group of B-cells was recognized in the endoneurial space of a nerve provided with a continuous multi-layered perineurial sheath. The endocrine cells together with unmyelinated axons were enveloped by cytoplasmic processes of Schwann cells. A synaptic-like structure was occasionally noted on the surface of an endocrine cell. The neurotropism of endocrine cells (WATZKA, 1931) which leads to the formation of pancreatic neuro-insular complexes is compared with the neurotropism of Leydig cells and ovarial interstitial cells. It is suggested that such neuro-endocrine complexes generally communicate via vascular connections to the target organs or target tissues.

Vomeronasal tissues from four male gnotobiotic calves were prepared for transmission and scanning electron microscopy. Features described include: non-myelinated nerves in the non-neurosensory lamina propria, capillaries in the base of the neurosensory epithelium, sustentacular cells with microvilli 22-26 micron long, neurosensory cells with numerous apical vesicles, cells with cytoplasmic projections containing dense bundles of filaments, and brush cells. The structurally well developed bovine vomeronasal organ is similar in other respects to that reported for a number of other mammals.

Immunoelectron microscopy using a colloidal gold-antibody method with anti-rat GH serum demonstrated three morphologically different types of GH cells in the rat anterior pituitary. They were distinguished as Types I, II and III GH cells, containing only large secretory granules about 350 nm in diameter, mixed large and small granules, and only small granules about 150 nm in diameter, respectively. Double gold labeling with large gold particles for GH and small particles for PRL or ACTH indicated that neither GH and PRL nor GH and ACTH were contained in the same cell. In adult male rats, Type I cells (68%) predominated over Type II (22%), while Type III cells were rare (9.7%). On the contrary, in the adult female rats, Type II cells (47%) slightly dominated over Type I (44%) though the rate of Type III cells was the same as in the male. In neonatal infants, the frequency of occurrence of Type III cells was as high as about 20%; sex differences between Types I and II were indistinct. The Type III cells were therefore thought to represent an immature type.

Immunostained sections and whole-mount preparations of the layers of the guinea pig jejunum were investigated by an improved peroxidase-antiperoxidase method using an antiserum to S-100 protein. A delicate latticework of S-100 protein immunopositive glial cells was demonstrated extending in the longitudinal muscle layer, myenteric or Auerbach's plexus, circular muscle layer including the deep muscular plexus, submucous layer including the submucous or Meissner's plexus, lamina muscularis mucosae and lamina propria mucosae. The whole enteric nerve plexuses consisted of two subsystems; nerve plexuses of the muscular coat and those of the submucous and mucous coats. These two subsystems were joined to each other by thick, connecting branches perforating the inner circular muscle layer. Extrinsic nerves entering the myenteric plexus formed a specialized junctional structure containing S-100 protein immunopositive glial cells, whereas those entering the submucous plexus ran along the submucous arteries. We proposed the term enteroglial cells to designate the S-100 protein immunopositive cells which ensheathed the somata and processes of the enteric neurons. The frameworks of all structures in the enteric nerve plexuses from the largest ganglia to the thinnest nerve fasciculi were constructed of these enteroglial cells. A spectrum of the enteroglial cells was presented. Those in the myenteric and submucous ganglia were found similar to the astroglia of the central nervous system and to the satellite cells in the peripheral ganglia. Those in the primary and secondary fasciculi of the myenteric plexus formed a kind of neuropil together with the neuronal processes. Those in the tertiary fasciculi of the muscular coat formed the framework of the autonomic ground plexus. We tentatively concluded that the interstitial cells of Cajal contain an immunoreactivity for S-100 protein, and thus are glial in nature. The occurrence of specialized enteroglial cells with a neuron-like function was discussed in the autonomic ground plexus of the muscular coat. In the lamina propria mucosae, there was a fine latticework of the S-100 protein immunopositive enteroglial cells. This latticework corresponded to that of the interstitial cells of Cajal in the villous and periglandular plexuses.

Leucocytes and thrombocytes in the chicken liver sinusoids were observed under normal conditions and after intravenous India ink perfusion. The monocytes exhibited conspicuous phagocytic activity. At 30 min or earlier and 4 hr after the perfusion, they ingested considerable amounts of the carbon particles, which were deposited in small vacuoles and/or lysosomes. In this study we revealed two transitional forms of the monocyte changing into the Kupffer cell. In one transitional form, which already at 15 min after the perfusion stored considerable amounts of the particles, the ectoplasmic layer was partly differentiated and projected many pseudopodia into the sinusoid. At 48 hr after the perfusion, the other transitional form was attached by its wide basal surface to the endothelial linig and projected well-developed pseudopodia into the sinusoid like the Kupffer cell without, however, storing the carbon particles. These findings are thought to suggest the transformation of the monocytes into the Kupffer cells. Thus we came to the assumption that the Kupffer cells might be replenished: by self-proliferation; by the macrophages from the hepatic parenchyme into the sinusoid; or by transformation from the monocytes circulating into the sinusoid (the "triple origin" as opposed to the "dual origin" of the Kupffer cell). In the earliest stage after India ink perfusion, the thrombocytes exhibited the most striking reaction comparable to the Kupffer cells toward which they were assembled. The India ink particles were taken up into the "surface connected canalicular system" (SCS), which thickened and made vacuolar expansions as the amount of the particles was increased. At 4 hr after perfusion, the particles disappeared from the majority of the thrombocytes, leaving an empty SCS. The India ink particle uptake and storage by the thrombocyte were thought to be temporary phenomena, different from the true phagocytosis of the macrophages.

The purpose of this study was to examine whether the basal laminae of Schwann cells in allografts could survive immunological rejection and serve as a conduit for regenerating nerves, as in the case of autogenic nerve grafts. Allografts of nerves were carried out using sciatic nerves of mice after the grafts had been repetitively frozen to kill their Schwann cells. Two mouse strains, C57BL/6N and C3H/HeN, were used, as they are known to differ in major histocompatibility complex. The mid-portion of the grafted nerve segments was examined by electron microscopy. In addition, the toe pad skin and lumbrical muscles were examined for determining whether regenerating nerves reinnervate sensory end organs and motor endplates. The process of nerve regeneration in the allograft was the same as that seen in the autograft. Cells in the graft disintegrated into cell debris and were phagocytized by macrophages, whereas the basal laminae of Schwann cells were not removed by macrophages, remaining in the form of tubes or scaffolds. Regenerating nerve fibers grew out through such basal lamina scaffolds, keeping in contact with the inner surface. Digital sensory corpuscles and motor endplates of the operated side were well reinnervated. The results indicate that the basal laminae of Schwann cells of the allograft may survive and serve as a conduit for regenerating axons in the same way as in the case of an autograft.

Ultrastructural features of folliculo-stellate cells of the anterior lobe of the pituitary gland were described in three rodent species (the mouse, guinea pig, golden hamster). These cells are agranular and form the lining of tiny follicles projecting microvilli. Long cytoplasmic expanding processes are intermingled with granular cells of various morphofunctional types without special relationships to one cell type or another. In the guinea pig, the abundance of intermediate filaments appears as a notable feature in the cytoplasm of the folliculo-stellate cells. The results are compared with those previously published.