摘要:

AbstractPrevious studies have shown that colchicine and vinblastine inhibit secretion in many cell types by interrupting the normal intracellular migration of secretory products. In the present work, radioautography has been used to study the effects of these drugs on migration of membrane and secretory glycoproteins in a variety of cell types. Young (40 gm) rats were given a single intravenous injection of colchicine (4.0 mg) or vinblastine (2.0 mg). At 10 min after colchicine and 30 min after vinblastine administration, the rats were injected with3H‐fucose. Control rats received3H‐fucose only. All rats were sacrificed 90 min after3H‐fucose injection and their tissues processed for light microscope radioautography.Examination of secretory cell types such as ameloblasts and thyroid follicular cells in control animals revealed reactions of approximately equal intensity over the Golgi region and over extracellular secretion products, while in drug‐treated rats most of the reaction was confined to the Golgi region. In a variety of other cell types, including endocrine cells (e.g., hepatocytes) and cells generally considered as nonsecretory (e.g., intestinal columnar cells), reaction in control animals occurred both over the Golgi region and over various portions of the cell surface. In drug‐treated animals, a strong Golgi reaction was present, but reaction over the cell surface was weak or absent.These results indicate that in many cell types, colchicine and vinblastine inhibit migration out of the Golgi region not only of secretory glycoproteins, but also of membrane glycoproteins destined for the plasma

ISSN:0002-9106    

DOI:10.1002/aja.1001700402

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

年代:1984

数据来源: WILEY

摘要:

AbstractYoung (40 gm) rats were given a single intravenous injection of colchicine (4.0 mg) or vinblastine (2.0 mg). At 10 min after colchicine and 30 min after vinblastine administration, the rats were injected with3H‐fucose. Control rats received3H‐fucose only. All rats were sacrificed 90 min after3H‐fucose injection and their tissues processed for radioautography.In thyroid follicular cells of control animals, at this time interval, 57% of the total label was associated with colloid and secretory vesicles in the apical cytoplasm while 27% was localized in the Golgi apparatus and neighboring vesicles. In experimental animals, the proportion of label in colloid and apical vesicles was reduced by more than 69% after colchicine and more than 83% after vinblastine treatment. The proportion of label in the Golgi region, on the other hand, increased by more than 125% after colchicine and more than 179% after vinblastine treatment. Within the Golgi region, the great majority of the label was associated with secretory vesicles which accumulated adjacent to the trans face of the Golgi stacks. It is concluded that the drugs do not interfere with passage of newly synthesized thyroglobulin from the Golgi saccules to nearby secretory vesicles, but do inhibit intracellular migration of these vesicles to the cell apex. In most cells the number of vesicles in the apical cytoplasm diminished, but this was not always the case, suggesting that exocytosis may also be partially inhibited. The loss of microtubules in drug‐treated cells suggests that the microtubules may be necessary for intracellular transport of thyrog

ISSN:0002-9106    

DOI:10.1002/aja.1001700403

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

年代:1984

数据来源: WILEY

摘要:

AbstractIn the first paper of this series (Bennett et al., 1984), lightmicroscope radioautographic studies showed that colchicine or vinblastine inhibited intracellular migration of glycoproteins out of the Golgi region in a variety of cell types. In the present work, the effects of these drugs on migration of membrane glycoproteins have been examined at the ultrastructural level in duodenal villous columnar cells and hepatocytes.Young (40 gm) rats were given a single intravenous injection of colchicine (4.0 mg) or vinblastine (2.0 mg). At 10 min after colchicine and 30 min after vinblastine administration, the rats were injected with3H‐fucose. Control rats received3H‐fucose only. All rats were sacrificed 90 min after3H‐fucose injection and their tissues processed for radioautography.In duodenal villous columnar cells,3H‐fucose labeling of the apical plasma membrane was reduced by 51% after colchicine and by 67% after vinblastine treatment; but there was little change in labeling of the lateral plasma membrane. Labeling of the Golgi apparatus increased. This suggests that labeled glycoproteins destined for the apical plasma membrane were inhibited from leaving the Golgi region, while migration to the lateral plasma membrane was not impaired. In hepatocytes, labeling of the sinusoidal plasma membrane was reduced by 83% after colchicine and by 85% after vinblastine treatment. Labeling of the lateral plasma membrane also decreased, although not so dramatically. Labeling of the Golgi apparatus and neighboring secretory vesicles increased. This indicates that the drugs inhibited migration of membrane glycoproteins from the Golgi region to the various portions of the plasma membrane. Accumulation of secretory vesicles at the sinusoidal front suggests that exocytosis may also have been partially inhibited. In both cell types, microtubules almost completely disappeared after drug treatment. Microtubules may, therefore, be necessary for intracellular transport of membrane glycoproteins, although the possibility of a direct action of these drugs on Golgi or plasma membranes must also be con

ISSN:0002-9106    

DOI:10.1002/aja.1001700404

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

年代:1984

数据来源: WILEY

摘要:

AbstractSequential alterations in 5‐fluorouracil‐treated hamster fetal palate were studied by light and electron microscopy and by acid phosphatase cytochemistry. At an early stage in 5‐fluorouracil‐treated fetuses, when the palatal shelves were vertical, lysosomes first appeared in cells of the prospective fusion epithelium and then in the cells of subjacent mesenchyme. In contrast to controls, increasing numbers of both the epithelial and mesenchymal cells of the vertical palate showed lysosomal injury in 5‐fluorouracil‐treated fetuses as development progressed. Subsequently, the basal lamina in the vertical palate showed alterations, characterized initially by disturbances in lamina lucida, by fingerlike extensions of lamina densa, and ultimately by its complete breakdown. At a later stage, when shelves became horizontal, the lysosomes were absent in both the epithelial and mesenchymal cells, and the basal lamina continuity was restored. Unlike controls, however, 5‐fluorouracil‐treated horizontal shelves never contacted one another. Instead, the epithelia of the horizontal shelves underwent stratification. It appears that premature formation of lysosomes in palatal epithelial and mesenchymal cells following 5‐fluorouracil treatment disrupts normal cytodifferentiation and affects the integrity of the basal lamina; both effects are associated with cleft

ISSN:0002-9106    

DOI:10.1002/aja.1001700405

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

年代:1984

数据来源: WILEY

摘要:

AbstractMorphological and developmental characteristics of the rhesus monkey nasopalatine duct system and associated primary palatal structures are described along with functional and phylogenetic considerations. Examination of five adult palates and coronal sections of 13 fetal palates together with dissections of a sixth adult specimen and of a 119‐day‐old fetal palate reveal that the lateral lobes of the tripartate incisive papilla cover clefts leading into the ducts. The ducts pierce the bony palate to enter the nasal fossae in proximity to the incisive suture. The ontogenetic stability of the duct path reflects the retention of ancient duct and primitive choanae relationships and functionally maintains an optimal oral odorant‐to‐receptor channel.Sixteen timed pregnancy specimens (35–100 days) provided histological material for documenting rostral nasopalatal development. Duct primordia, identified at 35 days, had by 40 days formed the medial duct walls (conjoined septum‐papilla from the primary medial palatal component), the lateral duct walls (maxillary processes), and the rostral walls (fused maxillary‐intermaxillary components). The caudal walls derive from the fusion of palatal shelves with the papilla (45 days), thus distinguishing primary and secondary fusion modes. Duct epithelial maturation occurs between 70 and 100 days.The absence of a vomeronasal system is attributed to reduction of olfaction in reproductive behavior, while the presence of the coevolved nasopalatine ducts is linked to the persistence of epiglottal‐velar valving. The ducts serve as oral food‐odor conduits in otherwise functionally separated respiratory and

ISSN:0002-9106    

DOI:10.1002/aja.1001700406

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

年代:1984

数据来源: WILEY

摘要:

AbstractThe morphogenesis of elastic fibers of the nuchal ligament, aorta, and lung of sheep was studied by light microscopy, transmission electron microscopy, and immunohistochemical methods for the detection of elastin. The degree of maturation of the amorphous materials of elastic fibers was assessed morphologically in preparations stained by the tannic acid and periodic acid methenamine‐silver methods. With both of these methods, the amorphous components of mature fibers stained less intensely than did those of immature fibers. Elastic fibers in early stages of development consisted of many microfibrils and few, small, branching masses of immature amorphous material. Thicker fibers were formed by the coalescence of growing masses of amorphous materials. In late stages of formation of elastic fibers, the mature amorphous materials were associated with few microfibrils; and they were partially surrounded by immature amorphous materials associated with many microfibrils. Antielastin antibody reacted evenly with amorphous materials in very early stages of elastic‐fiber development, but reacted only with the other zones of amorphous materials in later stages; it also reacted with the microfibrils in all stages. These findings were interpreted as indicating that the microfibrils were associated with small amounts of elastin on their surfaces. This conclusion is in agreement with ultrastructural observations showing (1) that development of microfibrils precedes that of the amorphous material and (2) that the microfibrils adjacent to the immature amorphous materials are covered with small amounts of tannnic acid‐positive amorphous materials. These observations suggest that microfibrils serve as sites for elastin deposition, both in early elastogenesis and in subsequent growth of elastic fibers. However, the nature of the interaction between elastin and microfibrils remains un

ISSN:0002-9106    

DOI:10.1002/aja.1001700407

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

年代:1984

数据来源: WILEY

摘要:

AbstractIn the developing rat mammary gland, terminal end buds (TEBs), lateral buds and alveolar buds represent the major sites of morphogenetic activity and cellular differentiation. The morphology and cellular composition of these buds from 20‐to 22‐day‐old rats and cycling rats have been studied by immunocytochemical and electron microscopic techniques. The mammary buds are composed of a heterogeneous collection of cells including epithelial and myoepithelial cells, irregular loosely adherent cells, and occasional large clear cells. The irregular, loosely packed cells or cap cells are mainly situated around the periphery of the TEBs and lateral buds. “Chains” of irregularly shaped cells also extend from the peripheral cap cell layer to the center of the TEB; and, where they converge on lumina, they display microvilli and junctional complexes. At the tips of the end buds, the cap cells are of undifferentiated appearance; however, similar cells situated toward the subtending mammary ducts show a gradation in ultrastructure to that of myoepithelial cells. This change is accompanied by an increase in the amounts of immunoreactive myosin and keratin seen within the cells and a 200‐fold increase in the thickness of the basement membrane. In contrast, the peripheral cells of the alveolar buds are more closely packed, contain a greater number of myofilaments, and show increased staining with antisera to myosin. We suggest that the undifferentiated cap cells do not represent a discrete cell type, since they show transitional forms to myoepithelial cells within the subtending mammary ducts, and that the tendency toward the myoepithelial phenotype is predominant in the more differentiated structures, the al

ISSN:0002-9106    

DOI:10.1002/aja.1001700408

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

年代:1984

数据来源: WILEY

ISSN:0002-9106    

DOI:10.1002/aja.1001700401

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

年代:1984

数据来源: WILEY