摘要:

AbstractBackground: The mammalian cochlea contains beneath and lateral to outer hair cells, several types of supporting cells. The function of these cells has not been explained beyond providing a structural base.Methods: The supporting cells of gerbil cochlea were examined by electron microscopy with a view to elucidating their biologic activity on the basis of cytologic structure.Results: Ultrastructural examination differentiated the laterally located Hensen cells from their medial neighbor connected to the third Deiters cell. The later cell formed a cover to the outer tunnel between Hensen and Deiters cells, appeared not to reach the basilar membrane, and exhibited a denser cytosol and more mitochondria, compared to Hensen cells. In these respects the cell observed here to cover the outer tunnel, corresponded with the tectal cell described by Henson et al. (1983) in the mustache bat, but not heretofore documented in other animals.Conclusions: This distinctive cell in the gerbil differend in displaying unique villus‐like structures which projected from the basomedial surface and are referred to as fimbriae. The fimbriae and interspersed filopodia largely filled outer tunnel space and expanded the cell's basal surface. The amplification of basal plasmalemma by fimbriae and their content of mitochondria testify to a role for the tectal cell in ion resorption and an influence on ion content and volume of outer tunnel fluid. © 1994 Wiley‐Liss,

ISSN:0003-276X    

DOI:10.1002/ar.1092400202

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractBacground: A rich supply of nerves to the atrioventricular valve has been demonstrated. The role of the valvular nerves is still controversial because the target sites of the nerves have not been confirmed.Methods: The innervation of the atrioventricular valves of the Japanese monkey (Macaca fuscata) was examined by acetylcholinesterase staining and electron microscopy. Immunoreactivity for neuropeptide Y (NPY) was also investigated by a post‐embedding immunogold method.Results: The valvular nerve elements were clearly concentrated between the endothelium and interstital cells on the atrial side of cusps. Naked axon terminals were observed to make direct contact (20‐nm gaps) with interstitial cells and also to be in close proximity (∼200‐nm cleft) to the endothelium. NPY immunoreactivity was clearly detected on the large granular vesicles in some terminals that were in close proximity to interstitial cells and/or the endothelium.Conclusion: The present study suggests that the extensive innervation of the atrioventricular valve, which includes NPY‐containing nerves, might affect valvular function via interstitial cells and/or the endothelium. © 1994 Wiley

ISSN:0003-276X    

DOI:10.1002/ar.1092400203

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractBackground: Speciamens of human anterior lingual salivary glans obtained by surgery and by dissection of cadavers were studied ultrastructurally and histochemically.Methods: Specimens were obtained by surgery for ultrastructural study. Other specimens for histochemistry were obtained by dissection of fresh cadavers. Tissues for electron microscopy were fixed and processed by conventional mesns. Formalin‐fixed cadaver specimens were subjected to a battery of tests for glycoconjugates.Results: The anterior lingual salivary glands are composed predominantly of mucous tubules (which come in two distinct sizes: large and small), seromucous demilunes, and rare seromucous acini. Regardless of tubule size, mucous cells are typically in appearance and, like mucous cells in other human salivary glands, contain filamentous bodies. Histochemically, the larger tubules contain neutral glycoproteins, low concentrations of sialoglycoproteins, and large amounts of sulfated glycoproteins. The small mucous tubules contain neutral glycoproteins, much sialoglycoprotein, and relatively small amounts of sulfated glycoprotein. The seromucous cells, whether demilunar or acinar, are identical. They contain numerous secretory granules, which show a spectrum of internal patterns from one individual to another. These cells have considerable concentrations of neutral‐ and sialoglycoproteins and lower concentrations of sulfated gly‐coproteins. Countrary to previously published reports, we could find no differences in the ratio of mucous to seromucous cells along the anteriorposterior lingual axis: there was no gradient of seromucous cells in our specimens. The ducts in the anterior lingual salivary glands are not precise counterparts of those in the major salivary glands, since the former have no capsules, hence lack lobulation. Without these familiar structural landmarks, the only duct that can be identified with certainty is the intercalated duct, and then only if it is in continuity with or lies close to a secretory endpiece. Such ducts consist of simple cuboidal epithelium of prosaic appearance. The ductular epithelium gradually thickens and gives rise to what appear to be excretory ducts consisting of columnar cells with few mitochondria. Scattered within the walls of the walls of the larger ducts are patches of typical striated ducts wherein the taller cells display basal striations resulting from highly folded basal plasma membranes and numerous, vertically oriented, virgulate mitochondria. In other atypical regions of the excretory duct, basal cells may have a primary cilium that juts into the intercellular space.Conclusions: There is a high degree of structural variability in human anterior lingual salivary glands. Because of the technical difficulties in collecting pristine saliva from these glands, the precise functions(s) of these organs remains unknown. © 1994 Wiley‐L

ISSN:0003-276X    

DOI:10.1002/ar.1092400204

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractBackground: Certain species of bats possess two sets of submandibular glands, namely, principal and accessory. The ultrastructure and histochemistry of the accessory submandibular gland was examined in three species of long‐winged bats.Methods: Specimens ofMiniopterus schreibersiandM. Magnatorwere live‐trapped in Thailand, and ofM. inflatuswere live‐trapped in Kenya. For electron microscopy, accessory submandibular lands were initially fixed in triple aldehyde‐DMSO, postfixed in osmium tetroxide, and embedded in Epon‐Maraglas. A portion of the glands collected in Thailand (M. schreibersiandmagnator) was fixed in buffered formalin and embedded in paraffin. Sections of the latter material were subjected to a battery of histochemical tests for glycoconjugates.Results: Although in all three species the accessory submandibular glands have normal histological structure, the glands in two,M. schreibersiandM. magnator, were distinguished by possessing mucous droplets of unusual morphology. These droplets, whose identity as mucous was confirmed by histochemical tests for glygoconjugates, are delimited by maniflod membranes: up to 10 inM. Schreibersiand fewer, but still multiple, inM. magnator. In both species, the entire array of surface membranes may fold inward in the fashion of mitochondiral cristae, forming packets of membranes, many of which have the spurious appearance of floating free in the droplet matirix. These multipartite limiting membranes appear to originate simply by Golgi saccules and moderately large, flattened Golgi vesicles repeatedly wrapping themselves around the surface of nascent mucous droplets. During exocytosis, the outermost membrane of each mucous droplet contacts the luminal membrane, this barrie ruptures, then the remainder of the droplet—multiple membranes and matrix—either flow into the lumen or are cast out in toto. In either case, a great deal of membrane phospholipid is added to the salivea. This salivary lipid may permit these bats to consume insects that normally are able to repel predators with chemical defenses that make them unpalatable. The thrid species that we studied,M. inflatus, has mucous droplets of normal appearance, i.e., they have only one limiting membrane.Conclusions: The varying structure of mucous secretory products among the species ofMiniopterusprovides important clues as to the evolution of this genus as well as to the evolution of secretory cells in general. © 1994 W

ISSN:0003-276X    

DOI:10.1002/ar.1092400205

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractBackground: The structure of nonregenerated and experimentally regenerated scales of the holostean fishLepisosteus oculatusand the events taking place before and during ganoine depostition on the scale surface were studied. The aim of this study was to answer the question of the origin of the ganoine in lepisosteids, the scales of which are devoid of dentine, and to compare them to ganoine formation in polypterid scales and to enamel formation in teeth.Methods: Two adult specimens were used and the scale structure was studied using light and transmission electron microscopy. Regeneration was used as an alternative to the lack of developmental stages and to induce ganoine deposition on the scale surface.Results: Nonregenerated scales are composed of a thick, avascular bony plate capped by ganoine that is covered either by the epidermis or by dermal elements. The ganoine surface is separated from the covering soft tissues by an unmineralized layer, the ganoine membrane. During the first 2 months of regeneration, the bony plate forms. It differs from the bony plate of nonregenerated scales only by its large, woven‐fibered central region and by the presence of numerous vascular canals. Shortly before ganoine deposition, the osteoblasts cease their activity and an epithelial sheet comes to contact them and spreads on the bony surface. This epithelial sheet is connected to the epidermis by a short epithelial bridge only and is composed of two layers: the inner ganoine epithelium (IGE), in contact with the bone surface and composed of juxtaposed columnar cells that synthesize the ganoine matrix, preganoine; the outer ganoine epithelium (OGE), composed of elongated cells, the surface of which is separted from the overlying dermal space by a basal lamina. Isolated patches of preganoine are deposited by the IGE cells in the upper part of the osteoid matrix of the scale. The interpenetrated preganoine and osteoid matrices constitute an anchorage zone, between ganoine and bone. Preganoine patches fuse and a continuous layer of preganoine is progressively synthesized by the IGE cells. Preganoine progressively mineralizes to become ganoine.Conclusions: The processes of ganoine formation are similar to those known for the ganoine in the polypterid scales and to those described for enamel deposition in teeth. Ganoine is enamel. © 1994 Wiley‐Liss,

ISSN:0003-276X    

DOI:10.1002/ar.1092400206

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractBackground: Ageing and osteoarthritic (OA) cartilage show characteristic alterations in chondrocyte morphology and in the composition and content of matrix proteoglycans (PGs). Data concerning matrix components are mostly of biochemical nature. Ultrastructural histochemistry is needed to gain more information about distribution of these altered matrix components.Methods: We used the cationic dye polyethyleneimine (PEI) to visualize at the EM level alterations in the distribution and dimensions of PGs of human healthy young, healthy aged, and OA articular cartilage.Results: Young cartilage contained PEI‐positive granules in the superficial layer and big winding PEI‐positive structures in the deeper layers. In the healthy aged tissue, PEI‐positive granules were observed throughout the matrix and smaller winding structures were present in the deeper layer. In OA cartilage both types of PEI‐positive structures were absent in the superficial layer. Deeper in the matrix PEI‐positive granules could be demonstrated. Moreover, PEI‐positive angular structures were observed in the deeper zones.Conclusions: The differences in PEI‐positive structures are a good reflection of the differences in PGs between young, ageing, and OA cartilage as demonstrated in biochemical studies. PEI, used at the EM level, gave more precise information concerning the localized changes in quality, quantity, and location of PGs in articular cartilage during ageing and disease. © 1994 W

ISSN:0003-276X    

DOI:10.1002/ar.1092400207

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractBackground: To examine whether the complex branched fibers observed in mdx mutant mice were formed in normal skeletal muscles, long‐term repetitive muscle trauma was applied to muscle of normal Wistar male rats.Methods: Three kinds of artificial muscle trauma—crush injury, bupivacaine hydrochloride treatment, and forced stretching of contracting muscle (eccentric contraction)—were performed once a week for 10 weeks to achieve a state of repetitive degeneration and regeneration in the muscles. Two weeks after the final treatment, numerical, histochemical, and three‐dimensional analyses by scanning electron microscopy were performed.Results: Mean numbers of total branched fibers of the three groups were increased compared with normal control values, especially in the bupivacaine treatment group (three‐ to fivefold greater than in the other two groups). Aggregations of fibers of the same type which usually appear in mdx mice were observed in various parts of histological sections of the bupivacaine treatment group and only in a part of the crush injury group. No aggregations were observed in sections of the forced stretching group. In the three‐dimensional analysis, complex branched fibers appearing as an “anastomosing syncytial reticulum” were observed only in the bupivacaine treatment group.Conclusions: These findings suggest that the formation of an anastomosing syncytial reticulum is one of the adaptation mechanisms of normal skeletal muscle rather than a specific event in mdx mutant mice, and long‐term repeated trauma of the same fiber is necessary for this formation. Adaptive changes in the muscles with the three different types of muscle trauma are discussed. © 19

ISSN:0003-276X    

DOI:10.1002/ar.1092400208

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractBackground: Paracrine effects of germ cells on Sertoli cell structure were examined in a mouse model with the W locus (dominant white spotting) mutation in which animals with the W/Wvgenotype (referred to as mutants) lack virtually all germ cells.Results: Morphometric determination of Sertoli cell parameters in mutant and control (+/+) animals showed that although the testes of mutant animals were about eight times smaller than controls, the numbers of Sertoli cells in the two groups did not differ. Sertoli cell volume, Sertoli cell cytoplasmic and nuclear volumes, and Sertoli cell surface area in mutant animals were significantly smaller than in control animals. Organelle volumes and surface areas, expressed per cell, did not differ significantly in the two groups with one exception: the volume and surface area of smooth endoplasmic reticulum was significantly reduced in mutant animals. Plasma testosterone levels and tissue testosterone levels/testis were normal, indicating that the effects observed in the mutant animal were not a consequence of androgen insufficiency. Plasma FSH was elevated, probably as a consequence of germ cell depletion, and was thought not to affect Sertoli cell parameters observed.Conclusions: The data suggest that paracrine interactions with germ cells do affect Sertoli cells by modifying the amount of smooth endoplasmic reticulum. These data focus attention on the function of this abundant Sertoli cell organelle in promoting spermatogenesis. © 1994 Wiley‐Liss, I

ISSN:0003-276X    

DOI:10.1002/ar.1092400209

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractBackground: The morphology of placental detachment sites and the distribution of macrophages were studied in the mouse uterus from day 1 to 3 months post partum.Methods: Uterine morphology was studied using H&E and Mallory's Trichrome staining. Macrophages were identified using the macrophage‐restricted antigens F4/80 and FA/11 and the leukocyte β2‐integrin CR3 (Mac‐1) which is also expressed by neutrophils.Results: The post‐partum wound was infiltrated by large numbers of CR3+ F4/80+ FA/11+ macrophages, and CR3+ neutrophils. The wound resolved rapidly and no inflammatory infiltrate or necrotic tissue was seen by day 5 post partum. The area of the detachment wound and the site of the metrial gland of pregnancy resolved into a structure, here called a postpartum nodule, which persisted for at least three months. The post‐partum nodule consisted of an outer layer of collagen around a group of nodule‐specific cells which could be divided into haemosiderin‐ and lipid‐bearing phenotypes. The lipid‐bearing nodule cells were not found after day 20 post partum. Nodule cells were FA/11+ at all times and also expressed leukocyte common antigen. Expression of CR3 and F4/80 was found on nodule cells up to day 9–10 post partum. CR3 expression was found only occasionally after day 10.F4/80 expression was downregulated from day 9–10 to day 20 but was found consistently after day 20. Implantations of second and subsequent pregnancies are known not to occur in the immediate vicinity of post‐partum nodules and nodules from successive pregnancies were seen to be separate within the uterus.Conclusions: Since the endometrial area in the immediate vicinity of nodules is inimical to implantation and nodules consist of a group of macrophages, it can be implied that nodule macrophages are exerting some influence on the endometrium in their vicinity

ISSN:0003-276X    

DOI:10.1002/ar.1092400210

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractBackground: The cartilago cordis, a cartilaginous element present within the heart, has been found in a number of vertebrates. The present study provides a detailed description and comparative analysis of the cartilago cordis in snakes.Methods:Transverse sections through the hearts of 42 snakes and three monitor lizards were examined.Results: A cartilago cordis was found near the roots of the aortic trunk and pulmonary artery in eleven species of snakes. There is substantial variation in the size, shape, and precise location of the cartilago cordis.Conclusions: The presence of a cartilago cordis does not correlate with body size, taxonomic relationships, or habitat preference. The cartilago cordis may simply represent an illustration of the potential for chondrification that is present in the connective tissue of the aorticopulmonary septum. © 1994 Wiley‐Liss, I

ISSN:0003-276X    

DOI:10.1002/ar.1092400211

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY