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  • 1
    Electronic Resource
    Electronic Resource
    Electron microscopical study of self-differentiation potency in the chick embryonic endoderm cultured in vitro (1983)
    Springer
    Development genes and evolution 192 (1983), S. 171-178 
    Details
    ISSN: 1432-041X
    Keywords: Differentiation ; Digestive tract ; Endoderm ; Organ culture ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The self-differentiation potency of the endoderm of the chick embryo was investigated mainly by transmission electron microscopy. Endodermal fragments isolated from 4- to 6-day stomach or small intestine were cultured in the absence of mesenchyme and were able to differentiate in vitro into organ-specific epithelia. Endodermal fragments isolated from the stomach region differentiated into a pseudo-stratified epithelium with periodic acid Schiff-positive mucous granules in the apical cytoplasm, while those from the small intestinal region differentiated into a simple columnar epithelium with a striated border which was positive in alkaline phosphatase activity. These features are comparable with those of the mucous secretory epithelium of the normal embryonic stomach and the absorptive epithelium of normal embryonic small intestine, respectively. Next, the self-differentiation potencies were investigated of the upper and lower layers of the blastoderms, at stages 1–5 of Hamburger and Hamilton (H. and H.). Both stomach-type and small-intestine-type epithelia developed only when fragments of the lower layer isolated from the blastoderms older than stage 3 of H. and H. were cultured, suggesting that cells possessing the potency to differentiate into the stomach- and small-intestine-type epithelia exist in the definitive endoderm at the beginning of its formation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848687
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  • 2
    Electronic Resource
    Electronic Resource
    Demonstration of sucrase immunoreactivity of the brush border induced by duodenal mesenchyme in chick stomach endoderm (1992)
    Springer
    Development genes and evolution 201 (1992), S. 389-392 
    Details
    ISSN: 1432-041X
    Keywords: Sucrase-Brush border ; Mesenchymal induction ; Stomach endoderm ; Immunoelectron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary When stomach endoderm of chick embryos was recombined and cultured with duodenal mesenchyme, the endoderm developed a brush border structure over a large area and also differentiated into mucous cells in a small area according to its own developmental fate. In the present investigation, we examined whether the induced brush border structure expressed sucrase antigen by immunoelectron microscopy using the antiserum raised against chicken sucrase. Sucrase immunoreactivity could be detected as ferritin particles in the region where the brush border was induced, whereas it was never detected on microvilli of endodermal cells which differentiated into the mucous cells. Thus, almost all of the endodermal cells could be identified as either small intestine-type cells possessing the sucrase antigen or stomach-type cells possessing mucous granules but not the sucrase antigen. The results indicate that stomach endodermal cells of chick embryos can differentiate not only morphologically but also functionally into typical intestinal epithelial cells under the inductive influence of the duodenal mesenchyme.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00365127
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  • 3
    Electronic Resource
    Electronic Resource
    Chronological analysis of the intestinalization of chick stomach endoderm induced in vitro by duodenal mesenchyme (1985)
    Springer
    Development genes and evolution 194 (1985), S. 301-305 
    Details
    ISSN: 1432-041X
    Keywords: Intestinal induction ; Organ culture ; Stomach endoderm ; ultrastructure ; Cell contacts
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Inductive action of duodenal mesenchyme on stomach endoderm in the chick embryo was chronologically analysed in vitro by the use of electron microscopy and immunofluorescence techniques. The behaviour of the endoderm-mesenchyme interfaces was particularly studied during the induction. In recombinates of 4-day stomach endoderm and 6-day duodenal mesenchyme, all the endodermal cells were undifferentiated at the start of cultivation. Small-intestinal sucrase antigen could first be detected on the 5th day of cultivation in one-third of the stomach endoderm, and a striated border on the 7th day. With a longer cultivation period, intestine-type cells increased in number in the stomach endoderm and the density of microvilli on the apical surface became higher. At the endoderm-mesenchyme interfaces a number of direct contacts between endodermal and mesenchymal cells were observed from the beginning to the end of cultivation. These were especially abundant in the early period before the appearance of signs of intestinal cytodifferentiation. These results suggest that the mesenchymal cells adjacent to the endodermal tissue play an important role in the intestinal induction which occurs during the early period of cultivation, probably via direct cell-to-cell contracts.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01152176
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  • 4
    Electronic Resource
    Electronic Resource
    Connective tissue is involved in adult epithelial development of the small intestine during anuran metamorphosis in vitro (1992)
    Springer
    Development genes and evolution 201 (1992), S. 322-329 
    Details
    ISSN: 1432-041X
    Keywords: Intestinal epithelium ; Anuran metamorphosis ; Organ culture ; Tissue interaction ; Regional difference
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The role of connective tissue in metamorphic changes of the small intestinal epithelium inXenopus laevis tadpoles was investigated by using organ culture techniques and electron microscopy. Tissue fragments isolated from various parts of the small intestine at stage 57 were cultivated. Larval cell death of the epithelium was induced by thyroid hormone in all fragments, whereas adult epithelial development was observed only in fragments isolated from the anterior intestinal region containing the typhlosole where most of the larval connective tissue was localized. The epithelium was then cultivated in recombination with homologous or heterologous non-epithelial components. The adult epithelium developed only in recombinants containing a thick connective tissue layer from the typhlosole. There was no regional difference in the developmental potency of the epithelium itself. In all explants where adult epithelium developed, the connective tissue increased in cell density just beneath the epithelium, which was rapidly proliferating and forming typical islets. At the same time, fibroblasts possessing well-developed rough endoplasmic reticulum differentiated close to epithelial cells and often made contact with them. These results indicate that the connective tissue originating from the typhlosole plays an important role in adult epithelial development of the anuran small intestine, probably via direct cell-to-cell contacts or some factor(s) synthesized by the fibroblasts.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00592113
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  • 5
    Electronic Resource
    Electronic Resource
    Cell-specific and spatio-temporal expression of intestinal fatty acid-binding protein gene during amphibian metamorphosis (1994)
    Springer
    Development genes and evolution 204 (1994), S. 150-155 
    Details
    ISSN: 1432-041X
    Keywords: Fatty-acid-binding protein ; Intestinal epithelium ; In situ hybridization ; Anuran metamorphosis ; Regional difference
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Intestinal fatty acid-binding protein (IFABP) gene is known to be regulated during Xenopus metamorphosis. To determine the relationship between its regulation and cellular differentiation during metamorphosis, we have examined the distribution of IFABP mRNA in the Xenopus digestive tract by in situ hybridization techniques. Throughout all stages examined, transcripts of IFABP gene were observed exclusively in absorptive epithelial cells of the small intestine, and they decreased in amount towards the posterior intestine. Around stage 58, just before metamorphic climax, IFABP mRNA level began to decrease in larval absorptive cells that still remained intact morphologically. Thereafter, IFABP mRNA was no longer detected among larval cells. In turn, at stage 62, IFABP mRNA became detectable in some of the newly formed adult epithelium that had not yet developed a brush border, but not in the remaining larval cells. By the end of metamorphosis, IFABP mRNA became more abundant towards the crest of intestinal folds. These results suggest that IFABP gene expression is specific for absorptive epithelial cells of the small intestine and is regionally regulated along the intestinal anterior-posterior axis in both tadpoles and frogs and also along the trough-crest axis of frog intestinal folds. In addition, our present study directly shows that IFABP mRNA level decreases in larval absorptive cells but increases in adult ones during metamorphosis, preceding morphological changes of both types of cells. Therefore, the regulation of IFABP gene is an early event during both larval epithelial cell death and adult epithelial cell differentiation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00361110
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  • 6
    Electronic Resource
    Electronic Resource
    Autoactivation ofXenopus thyroid hormone receptor β genes correlates with larval epithelial apoptosis and adult cell proliferation (1997)
    Springer
    Journal of biomedical science 4 (1997), S. 9-18 
    Details
    ISSN: 1423-0127
    Keywords: Thyroid hormone receptor ; Xenopus laevis ; Metamorphosis ; Apoptosis ; Cell proliferation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The thyroid hormone (T3)-dependent amphibian metamorphosis involves degeneration of larval tissues through programmed cell death (apoptosis) and concurrent proliferation and differentiation of adult cell types. As the mediators of the causative effects of T3 on metamorphosis, both thyroid hormone receptor (TR) α and β genes have been found to be expressed in different tissues during this process. In particular, theXenopus TRβ genes have been shown to be regulated by T3 at the transcriptional level and their expression correlates with organ-specific metamorphosis. We demonstrate here by in situ hybridization that theXenopus TRβ genes are regulated in a cell-type specific manner that correlates with tissue transformation. In particular, they are found to be expressed in the larval intestinal epithelial cells prior to their apoptotic degeneration and in the proliferating cells of the adult epithelium, connective tissue, and muscles. However, they are repressed again upon the differentiation of these adult cells. These results implicate that TRβ participates both in inducing apoptosis and stimulating cell proliferation during development.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02255588
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  • 7
    Electronic Resource
    Electronic Resource
    Transient expression of stromelysin-3 mRNA in the amphibian small intestine during metamorphosis (1996)
    Springer
    Cell & tissue research 283 (1996), S. 325-329 
    Details
    ISSN: 1432-0878
    Keywords: Key words: Matrix metalloproteinase ; Intestine ; small ; Metamorphosis ; In situ hybridization ; Basement membrane ; Xenopus laevis (Anura)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. It has been suggested that a matrix metalloproteinase, stromelysin-3 (ST3), is an important enzyme for epithelial transformation; the ST3 gene is known to be regulated by thyroid hormone during Xenopus metamorphosis. In this study, we have examined the distribution of ST3 mRNA in the small intestine of Xenopus during metamorphosis by using in situ hybridization. Around stage 58, ST3 mRNA is first detectable in larval fibroblasts near the muscular layer, and then increases in amount throughout the entire region of connective tissue. By stage 61, when connective tissue cells are rapidly increasing in number, ST3 mRNA is localized in fibroblasts just beneath the epithelium. This localization of ST3 mRNA is in good temporal accordance with modification of the basement membrane and epithelial transformation from the larval to adult form. Thereafter, ST3 mRNA gradually decreases and is no longer detected after stage 63 when the adult epithelium has completely replaced the larval type. The transient expression of ST3 mRNA in the fibroblasts of connective tissue during metamorphosis indicates that it plays an important role in epithelial transformation by changing the basement membrane.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410050542
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  • 8
    Electronic Resource
    Electronic Resource
    Apoptosis and cell proliferation in the Xenopus small intestine during metamorphosis (1996)
    Springer
    Cell & tissue research 286 (1996), S. 467-476 
    Details
    ISSN: 1432-0878
    Keywords: Key words: Apoptosis ; Cell proliferation ; Intestine ; small ; Metamorphosis ; Basement membrane ; Immunohistochemistry ; Xenopus laevis (Anura)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. In the amphibian small intestine, the epithelial transformation from the larval to adult type is mainly the result of degeneration of the larval epithelium and development of the new (adult) epithelium. In this analysis at the cellular level, we chronologically examined apoptosis and cell proliferation in the Xenopus intestine by using in situ nick end-labeling of genomic DNA (TUNEL) and bromodeoxyuridine (BrdU) immunohistochemistry. During pre- and prometamorphosis, few apoptotic cells were detected by TUNEL, and a small number of proliferating cells randomly distributed in the larval epithelium were labeled by BrdU. At the beginning of the metamorphic climax, when primordia of the adult epithelium were first detected, numbers of apoptotic cells suddenly increased in the larval epithelium, whereas numbers of proliferating cells increased only in the adult epithelium. Subsequently, a dramatic cell loss of the larval epithelium and a rapid growth of the adult epithelium occurred. Following complete epithelial replacement, the adult epithelium became differentiated into a simple columnar epithelium possessing a cell renewal system similar to that of mammalian intestinal epithelium. These results indicate that larval epithelial apoptosis progresses simultaneously with active proliferation of the adult epithelium during the early period of metamorphic climax, which coincides with the modification of the basement membrane lining both types of epithelia.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410050716
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  • 9
    Electronic Resource
    Electronic Resource
    Local disturbance of neuronal migration in the S-100β-retarded mutant mouse (1997)
    Springer
    Cell & tissue research 289 (1997), S. 547-551 
    Details
    ISSN: 1432-0878
    Keywords: Key words: Bromodeoxyuridine (BrdU) ; Glial fibrillary acidic protein (GFAP) ; Immunohistochemistry ; Neuron-glia interaction ; Cortex ; Polydactyly mutant mouse (Pdn/Pdn; Pdn/+; +/+)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. Homozygotes of a mouse strain with genetic polydactyly (Pdn) show disrupted cortical lamination and a significant decrease of S-100β-immunoreactive elements in a particular area of the brain. In order to understand the abnormal cortical formation at the cellular level, the migration of cortical neurons and the development of glial cells were studied using bromodeoxyuridine (BrdU), S-100β, and glial fibrillary acidic protein (GFAP) immunohistochemistry. Homozygous mice (Pdn/Pdn) displayed a variable pattern of abnormalities. Irregular GFAP-positive radial glial cells and disturbance of neuronal migration were found in a circumscribed area of the caudo-dorsal cortex of newborn Pdn mouse. The number of S-100β-positive cells was reduced in this area. The present results suggest that abnormal cortical lamination closely correlates with disturbance of neuronal migration and abnormalities of glial cells, especially a significant decrease of S-100β-immunoreactive cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004410050900
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  • 10
    Electronic Resource
    Electronic Resource
    Inductive action of epithelium on differentiation of intestinal connective tissue of Xenopus laevis tadpoles during metamorphosis in vitro (1994)
    Springer
    Cell & tissue research 277 (1994), S. 427-436 
    Details
    ISSN: 1432-0878
    Keywords: Anuran metamorphosis ; Small intestine ; Macrophage ; Fibroblast ; Tissue interaction ; Differentiation ; Organ culture ; Xenopus laevis (Anura)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The action of the epithelium on differentiation of connective tissue cells of Xenopus small intestine during metamorphosis was investigated by using culture and morphological techniques. Connective tissue fragments isolated from the small intestine at stage 57 were cultivated in the presence or absence of homologous epithelium. In the presence of the epithelium, metamorphic changes in the connective tissue were fully induced by hormones including thyroid hormone (T3), as during spontaneous metamorphosis, whereas they were partially induced in the absence of the epithelium. Macrophage-like cells showing non-specific esterase activity in the connective tissue were much fewer in the absence of the epithelium than in the presence of it, and aggregates of fibroblasts possessing well-developed rough endoplasmic reticulum developed only in the presence of the epithelium. Just before the aggregation of the fibroblasts, the connective tissue close to the epithelium became intensely stained with concanavalin A (ConA) and wheat germ agglutinin (WGA). The present results indicate that the epithelium plays important roles in the differentiation of intestinal connective tissue cells, which in turn affect the epithelial transformation from larval to adult form during anuran metamorphosis. Thus, the tissue interaction between the epithelium and the connective tissue in the anuran small intestine is truly bidirectional.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00300215
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