摘要:

AbstractWe developed a constant‐pressure vascular perfusion system of the isolated rat stomach, utilizing an artificial, fluorocarbon (FC‐75)‐containing medium. Perfusion could be maintained for at least six hours, as demonstrated by the ultrastructure of the mucosal cells and by the constant incorporation of [3H]‐galactose in the surface mucous cells. Moreover all mucous cell types in tissue fixed after six hours of perfusion showed the same histochemical reactions for glycoproteins as in tissue fixed shortly after decapitation of the animal.The surface mucous cells of the antrum incorporated 30% less [3H]‐galactose, [3H]‐serine and [35S]‐sulphate than those of the fundus. The amount of radioactivity incorporated per cell did not decrease during a subsequent

ISSN:0002-9106    

DOI:10.1002/aja.1001560302

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

年代:1979

数据来源: WILEY

摘要:

AbstractLabeled leucine, serine, galactose, glucosamine and sulphate were administered to rat stomachs in a perfusion system. Sections of the gastric fundus were studied by light microscopic autoradiography. Five categories of mucous cells were distinguished and their glycoprotein synthetic activity was measured in autoradiographs by counting silver grains over each category. During their differentiation, while migrating from the isthmus of the fundic glands to the free luminal surface, the surface mucous cells (SMC) showed an increase in incorporation of all precursors used. Differences between the incorporation patterns of the various precursors, in cells of different ages, suggest that structural development runs ahead of functional activity, and that the latter continues up to the very moment the cell is shed from the surface. Sulphate was incorporated at a considerably lower rate by the SMC of the free surface than by the foveolar SMC, in which by cytochemical staining strongly acidic glycoproteins were shown. Since the mucous neck cells incorporated all precursors at a low rate, these cells apparently do not play an important role in gastric mucus synthesis. They did not incorporate sulphate, which is consistent with histochemical observations.

ISSN:0002-9106    

DOI:10.1002/aja.1001560303

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

年代:1979

数据来源: WILEY

摘要:

AbstractThis present study describes an experimental approach whereby subcellular 3‐dimensional filamentous structures present within whole cells can be examined, using a conventional transmission electron microscope. This procedure uses cells which have been cultured on carbon‐coated titanium grids, and treated with Triton X‐100 to extract the soluble cytoplasm. Subsequent fixation and critical‐point drying allows filamentous proteins to be easily visualized, due to the increase in contrast produced by removal of the ground cytoplasm. The high resolution obtainable in these preparations permitted an initial classification and description of the filamentous reticulum within cultured presumptive myoblasts. This reticulum is a continuum of filaments and cables, all elements of which appear to be interconnected. These morphological findings were then correlated with the biochemical identification of detergent‐insoluble proteins, of which only actin, myosin, and, perhaps, intermediate filament and LETS protein are the major

ISSN:0002-9106    

DOI:10.1002/aja.1001560304

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

年代:1979

数据来源: WILEY

摘要:

AbstractMucosa from the hard and soft palates, molar gingiva, cheek and dorsal surface of the tongue of the rat was examined in the light microscope, following Mallory's triple connective tissue stain, and in the scanning and transmission electron microscopes. The epithelium covering the hard palate, gingiva, the smooth band of mucosa at the junction of the hard and soft palates, intermediate zones of the soft palate, fungiform papilla‐like structures in the central zone of the soft palate, the fungiform papillae, and the more superficial part and posterior surfaces of the filiform papillae of the tongue all exhibited complete orthokeratinization. The oral surfaces of the epithelial cells in all these areas had a honeycomb pattern of interconnecting ridges surrounding depressions. Imprints of the overlying cells that had been desquamated were apparent, and the lateral boundaries between the cells were formed by two raised ridges separated by a gap. The epithelium covering the cheek, central zone of the soft palate apart from the fungiform papilla‐like structures, lateral zones of the soft palate, gingival crevice, and the mucosa between the fungiform and filiform papillae of the tongue all exhibited incomplete orthokeratinization. The oral surfaces of the epithelial cells in all these areas were relatively smooth and did not exhibit a honeycomb pattern of interconnecting ridges. Imprints of the overlying cells that had been desquamated and the lateral boundaries between the cells were only very occasionally found. In the transmission electron microscope the outlines of the cells were compatible with the surface patterns seen in the scanning electron microscope. The possible relationships between the degree of orthokeratinization and ultrastructure of the various epithelia are discus

ISSN:0002-9106    

DOI:10.1002/aja.1001560305

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

年代:1979

数据来源: WILEY

摘要:

AbstractThe effects of incubation of rat anterior pituitary cells in monolayer culture with 10−6Mcolchicine have been investigated during timeintervals extending from 1 to 96 hours. Prolactin release, as measured by radioimmunoassay, was rapidly inhibited by colchicine, this inhibition being accompanied by increased cellular prolactin content for up to 24 hours of treatment and followed by decreased values of cellular prolactin concentration at later time‐intervals. Immunocytochemical localization showed an increased positive reaction for prolactin up to 24 hours after colchicine treatment, whereas transmission electron microscopy demonstrated, in parallel, an increased number of intracellular prolactin secretory granules during the same interval. Longer periods of treatment (24–96 hours) resulted in the appearance of more lysosomes, autophagic vacuoles and microfilaments in the cells, whereas the number of Golgi elements was decreased. Following four hours of colchicine treatment and at later stages, microtubules could no longer be observed in the sections. Scanning electron microscopic data showed that colchicine treatment induced dramatic changes in the cell surface morphology: at short time intervals (4 and 8 hours), the number of microvilli decreased and the cell surface became folded, whereas, later, “bleb”‐like protrusions of variable dimensions partially covered the cell surface and seemed to be released from it. These data show a good correlation between secretory activity of prolactin‐producing cells and morphological changes induced by colchic

ISSN:0002-9106    

DOI:10.1002/aja.1001560306

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

年代:1979

数据来源: WILEY

摘要:

AbstractThe fine structure of the epithelium lining the extratesticular rete testis, ductuli efferentes and ductus epididymidis of the rabbit has been investigated. In the ductuli efferentes the epithelium is composed of two cell types, principal cells and ciliated cells. The latter cell type is distinguished from principal cells by the presence of cilia projecting into the lumen and the position of the nucleus in the apical half of the cell. Principal cells in this segment are characterized by micropinocytotic vesicles on the surface plasma membrane and a variety of small dense bodies scattered throughout the cytoplasm. In the ductus epididymidis basal cells replace ciliated cells as the second cell type, but differences between various segments of the epididymis are related to the fine structure of the principal cells. In the proximal caput epididymidis (Nicander's region 1) the principal cells are tall with long microvilli. They typically contain a small Golgi apparatus and a cluster of dense bodies adjacent to the nucleus. In the distal caput epididymidis (Nicander's regions 2–5) the apical cytoplasm of principal cells is filled with numerous micropinocytotic vesicles and large multivesicular bodies; these features are interpreted as signs of absorptive activity. The multivesicular bodies are absent from the cytoplasm of principal cells in the corpus epididymidis (Nicander's region 6) and, instead, numerous elements of smooth endoplasmic reticulum, a large Golgi apparatus, lipid droplets and dense bodies characterize principal cells in this segment. Towards the proximal cauda epididymidis (Nicander's region 7), the number of dense bodies (lysosomes) in the cytoplasm increases considerably. In the globose cauda (Nicander's region 8), the principal cells are reduced in height, and in addition to the features described in region 7, are characterized by a concentric array of rough endoplasmic reticulum in the basal cytoplasm. These observations are discussed in relation to the role of the epididymis in promoting the maturation and survival of spermatozo

ISSN:0002-9106    

DOI:10.1002/aja.1001560307

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

年代:1979

数据来源: WILEY

摘要:

AbstractSmall (60‐90 μm) and large (100‐130 μm) preantral follicles were isolated from adult mouse ovaries by a collagenase‐dissection technique. These follicles were composed of resting oocytes surrounded either by granulosa cells, only, or by granulosa and undifferentiated theca cells. Further enzymatic dissociation of primary follicles yielded monodisperse cells characterized by abundant rough endoplasmic reticulum, microfilament‐rich pseudopodia and only scant lipid droplets. These cells reaggregated, when explanted in stationary culture, forming epithelial cords and structures macroscopically reminiscent of native ovarian follicles. Anticipated association of follicular cells in epithelial‐like monolayers was rare (≤ 10% of all cultured cells). Formation and growth of both follicle‐like (FLS) and cord‐like (CLS) structures occurred within 24 hours of culture, continued for 14 days, and was inhibited by cytochalasin B, but not by neuraminidase. FLS and CLS, as well as cell monolayers, underwent luteinization, as indicated by the presence in the culture medium of radioimmunoassayable progesterone and by frequent cytological features suggestive of active steroidogenesis. The present report indicates that (a) specific cell affinities exist among immature follicular cells which may play a role in folliculogenesis; and (b) follicular cells are endowed, from their early developmental stages with intrinsic steroidogenic capabilities which become pheno‐typically expressed after escape from the intra

ISSN:0002-9106    

DOI:10.1002/aja.1001560308

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

年代:1979

数据来源: WILEY

ISSN:0002-9106    

DOI:10.1002/aja.1001560301

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

年代:1979

数据来源: WILEY