Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Endoderm”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 595 records · Page 33Linked to original sources
PubMed2001

Endodermal cyst of the oculomotor nerve.

Endodermal cysts are rare congenital intracranial lesions. Although histologically benign, they can become symptomatic as a result of mass effect and cause neurological deficits. We report a 30-year-old woman who presented with paresis of her right oculomotor nerve. Magnetic resonance imaging showed a 13 x 8-mm cystic lesion originating from the right oculomotor nerve at its exit from the mesencephalon. She underwent craniotomy, biopsy, slit resection, and drainage of the cyst. To our knowledge, endodermal cysts have not been previously described in relation to the oculomotor nerve.

Adult↗
PubMed1998

Effects of retinoic acid on the endoderm in Xenopus embryos.

When Xenopus embryos from mid-tailbud to early tadpole stages were exposed to retinoic acid (RA), the gut developed with an uncoiled, straight intestinal tube, morphogenesis of the liver and stomach was affected and intestinal epithelial cells developed without a brush border and alkaline phosphatase activity. However, the temporal and spatial expression pattern of X1Hbox 8, the only homeobox gene expressed in the endoderm was unaffected. In lateral plate mesodermal cells the expression of alpha-smooth muscle (SM) actin was delayed. A similar syndrome has been reported in a study of embryos lacking functional FGF receptors in which it was proposed that the uncoiled intestinal tube and the delayed differentiation of the intestinal muscle cells are causally related. Our results support this proposition and further suggest that mesenchymal-epithelial interactions concerned with regional specification of the endoderm may be impaired resulting in other defects in the gut.

Animals↗
PubMed2005

Primary endodermal sinus tumor of the cerebellar hemisphere: a case report with review of the literature.

Primary intracranial endodermal sinus tumors, which have been regarded as a rare histologic subtype, usually arise in the pineal and suprasellar regions and are often associated with components of other germ cell tumors. We report an extremely rare case of pure primary endodermal sinus tumor found in the cerebellar hemisphere. A 3-year-old boy was admitted to our institution because of gait disturbance, vomiting and deteriorated mental state. MR imaging revealed the presence of a round mass with heterogeneous enhancement in the left cerebellar hemisphere. Radical surgical removal of the tumor was performed, followed by adjuvant chemotherapy, consisting of etoposide, carboplatin and bleomycin. The patient has since attended regular follow-ups, without any neurological deficit or signs of recurrence in the 4 years since diagnosis.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1994

Posterior mediastinal endodermal sinus (yolk sac) tumor in a female patient.

Primary endodermal sinus tumor (yolk sac tumor) of the mediastinum is uncommon. Most patients are young and male, and the great majority of tumors are found in the anterior mediastinum. We report a case of primary posterior mediastinal endodermal sinus tumor occurring in a female patient. Surgical excision was performed and three courses of combination chemotherapy were subsequently given. The serum alpha-fetoprotein level returned to normal.

Adolescent↗
PubMed1985

Cell surface glycoproteins mediate compaction, trophoblast attachment, and endoderm formation during early mouse development.

Early mouse embryos undergo several morphogenetic processes, such as compaction, trophoblast attachment, and endoderm formation that can be studied in vitro. Several polyspecific and monospecific antisera have been used to perturb these processes in a nontoxic, reversible fashion. One of the antibody-defined molecules, cell CAM 120/80, promotes epithelial cell adhesion, embryo compaction, and endoderm formation. The results suggest the presence of another such molecule(s) involved in these same processes. Evidence is also presented that another set of antibody-defined molecules, GP 140, involved in attachment of somatic cells to the substrate, mediates trophoblast attachment of the mouse blastocyst. The possible role of these molecules in governing the processes leading to cell lineages in the mouse embryo is discussed.

Animals↗
PubMed1986

Fetal gut mesenchyme induces differentiation of cultured intestinal endodermal and crypt cells.

An experimental model was designed to analyze the effect of fetal gut mesenchyme on the cytodifferentiation of crypt cells and of embryonic progenitor cells. The cells used were the rat intestinal crypt cell line, IEC-17, and primary cell cultures prepared form isolated 14-day-old fetal intestinal endoderm (EC). Both cultures prepared from isolated 14-day-old fetal rat intestinal endoderm (EC). Both types of cells were associated with 14-day-old fetal rat gut mesenchyme (Rm) and grafted under the kidney capsule of adult rats. Seventy percent of the Rm/EC and ten percent of the Rm/IEC recombinants, recovered after 9 days, exhibited well-vascularized structures in which the mesenchyme had induced morphogenesis of the cells into a villus epithelium. The four main intestinal epithelial cell types, absorptive, goblet, endocrine, and Paneth cells, were identified using electron microscopy. Biochemical determinations of enzyme activities associated with brush border membranes revealed that alkaline phosphatase, lactase, sucrase, and maltase were expressed in both types of associations. These results were confirmed by immunofluorescence staining using monoclonal antibodies to brush border enzymes. Both enzyme assays and immunocytochemistry showed that the amount of enzymes present in the brush border membrane of Rm/IEC grafts was in general lower than that of the Rm/EC recombinants. The results indicate that fetal rat gut mesenchyme enables morphogenesis and cytodifferentiation of both crypt and embryonic progenitor cells.

Aminopeptidases↗
PubMed1990

Differential expression of fetomodulin and tissue plasminogen activator to characterize parietal endoderm differentiation of F9 embryonal carcinoma cells.

Fetomodulin is a surface marker protein of differentiated F9 embryonal carcinoma cells. Gene cloning has recently identified it as thrombomodulin which binds thrombin and proteolytically activates protein C. Activity assays and RNA blotting were adopted to analyze F9 cell differentiation with specific reference to another well-characterized marker, tissue plasminogen activator. Retinoic acid induced primitive endoderm differentiation of F9 cells and simultaneously activated tissue plasminogen activator synthesis. This differentiation, however, did not result in fetomodulin expression. When primitive endoderm cells were exposed to 1 mM dibutyryl cyclic AMP, the tissue plasminogen activator level rose further within 6 hr. In contrast, the cofactor activity of fetomodulin stayed below a detectable level for as long as 15 hr and then increased with time. Expression of the two marker proteins appeared to be regulated differently.

Animals↗
PubMed1991

Secretion of inhibin beta A by endoderm cultured from early embryonic chicken.

Although several reports have indicated a role for endoderm in the regulation of heart development, the mechanism remains unknown. To begin characterization of endoderm-secreted proteins, explants from postgastrulation (Hamburger-Hamilton stage 5/6-8) chicken embryos were cultured in defined medium. Fluorography of SDS-PAGE gels revealed a pattern of synthesized, secreted proteins that was independent of time in culture or embryonic stage when explants were removed. Approximately 10 labeled bands were detected, the most prominent of which migrated at 17, 25, and 200 kDa. ELISA analysis revealed that while acidic and basic fibroblast growth factor-like antigens were barely detectable, fibronectin and inhibin beta A were very reactive. Western blot analysis verified the presence of fibronectin and, most remarkably, inhibin beta A, activin dimers of which have recently been implicated in Xenopus mesoderm induction (Smith, Price, Van Nimmen, and Huylebrock (1990). Nature 345, 729.)

Activins↗
PubMed1994

The cis-element CE-LPH1 of the rat intestinal lactase gene promoter interacts in vitro with several nuclear factors present in endodermal tissues.

We have shown by electrophoretic mobility shift assays that the nucleotide sequence CE-LPH1, centred at position -49 with respect to the transcription start site of the rat gene encoding intestinal lactase-phlorizin hydrolase, interacts in vitro with nuclear proteins present in the jejunum of suckling animals. Proteins binding to this element were also found in organs of endodermal origin that do not (or no longer) express lactase-phlorizin hydrolase, i.e. the colon, lung and the liver, but not in the brain. However, a DNA-protein interaction was hardly detected with nuclear extracts prepared from adult tissues, although typical factors binding to the Sp1 binding site were detected at the adult stage as in the sucklings. Southwestern blotting experiments conducted with nuclear extracts prepared from the tissues of suckling rats indicated that CE-LPH1 interacts with several factors in the jejunum, colon, lung and the liver. Some of these DNA-binding proteins are specifically expressed in the jejunum or in the liver, whereas others seem to be shared with the colon and the lung. Hence, the cis-element CE-LPH1 located in close vicinity to the pseudo-TATA-box of the intestinal lactase-phlorizin hydrolase gene promoter interacts in vitro with a family of nuclear proteins which may represent markers of the endodermal lineage predominantly expressed prior to weaning.

Animals↗
PubMed1985

Assay and characterization of IgG binding to endodermal cells of the fetal rabbit yolk sac membrane.

The transfer of passive immunity in the rabbit is mediated by the fetal yolk sac membrane (YSM) and is initiated by the specific binding of IgG to receptors on the microvillar surface of the endoderm from the YSM. This report describes the preparation of suspensions of endodermal absorptive cells of the YSM and their use in equilibrium binding experiments to characterize the nature of the binding reaction. Equilibrium binding is achieved in 4 h at 4 degrees C. The system is more rapid than, affords greater reproducibility of binding data than, and utilizes only about 1/10 the amount of YSM and ligand as the YSM disc assay system (Tsay and Schlamowitz, 1975) used previously. A Scatchard plot of the binding data over a wide range of IgG concentration was non-linear implying the presence of at least 2 binding elements. Apparent binding constant values for the stronger and weaker binding components in this population differed by about 50-fold. For the weaker binding system, binding decreased when temperature was increased indicating that the reaction was not entropy-driven (i.e., dominated by hydrophobic 'forces') and that ionic interactions might be a major factor. At low ionic strengths the measurement of specific binding was complicated by the effects of secondary ionic interactions. At physiological ionic strength the binding of IgG was species-specific.

Animals↗
PubMed1985

Early specification for body position in mes-endodermal regions of an amphibian embryo.

Specification for development of the body pattern in the amphibian embryo has usually been thought of as a prolonged process, initiated from an ooplasmic localisation of some kind in what will become the dorsal-anterior midline. The evidence has been interpreted as suggesting that this initial localisation is centred in what will become anterior endoderm, but gives rise by an inductive process in early blastula stages to an overlying organising centre which eventually controls the genesis of mesodermal pattern. Neurectodermal development (especially, the position and pattern of the central nervous system) is seen as controlled considerably later, by inductive signals from submigrating mesoderm at gastrulation. Current work tends to confirm that this sequence of inductive influences can occur at least in experimental situations. It also suggests, however, that in the normal development of the rather small egg of Xenopus, genesis of positional cues that specify the body pattern contributions within the more vegetal material (mes-endoderm) is a rather rapid, widespread and direct consequence of events occurring in the interval between fertilisation and cleavage. Possible molecular bases of early nuclear responses to position within egg material, and the more problematic nature of the positional system itself, are discussed.

Animals↗
PubMed1988

Differentiation of intestinal and ectopic endocrine cells from avian gastric and pancreatic endoderm.

The chorio-allantoic grafts analysed were prepared from avian proventricular endoderm combined with its own or pancreatic mesenchyme and from re-associated pancreatic layers. Intestine developed ectopically in some grafts: in these, endocrine cells typical of intestine differentiated irrespective of the source of the endoderm or mesenchyme. In addition, endocrine cells inappropriate for the surrounding histology were detected in small numbers in grafts of all categories. Clearly it is not the mesenchyme that is responsible but perhaps some aspect of the procedure, which may relate to stressful stimuli thought to provoke intestinal metaplasia. The differentiation of inappropriate cells aids in understanding the occurrence of ectopic endocrine tumours.

Animals↗
PubMed1990

Pulmonary endodermal tumor resembling fetal lung: a clinicopathologic study of five cases with immunohistochemical and ultrastructural characterization.

Pulmonary endodermal tumor resembling fetal lung describes an uncommon neoplasm of the lung which also has been referred to as pulmonary blastoma and adenocarcinoma of fetal lung type. We describe five cases which fall within a narrow band on the spectrum of pulmonary neoplasms with both epithelial and mesenchymal features. These five cases all occurred as well-defined masses visible on chest radiograph in middle-aged females, and were treated by surgical excision. Histopathologically, low and high grades of malignancy are found. Well-formed racimose glands with cytoplasmic vacuolization resemble endometrioid carcinoma. Neoplastic columnar cells have abundant glycogen in the cytoplasm. Morules of cells within the glands have optically clear nuclei. Ultrastructurally, the optically clear nuclei are occupied by a filamentous substructure of chromatin. Multiple neuroendocrine hormones are present in low-grade malignancy. Nuclear pleomorphism, lymphatic invasion, multifocal necrosis, lack of mesenchyme at the pulmonary interface, and restricted neuroendocrine expression suggest high-grade malignancy. A mesenchymal stroma surrounding the glands is an intrinsic part of the neoplasm, but the stroma does not appear malignant, and did not form part of the metastasis in the single case where a metastasis occurred. Stromal cells show fibroblastic and myofibroblastic differentiation. Pulmonary endodermal tumor resembling fetal lung typically is a low-grade malignancy, with a better prognosis than the majority of lesions sometimes described as pulmonary blastoma or adenocarcinoma of fetal lung type.

Adult↗
PubMed1976

Plasminogen activator in early embryogenesis: enzyme production by trophoblast and parietal endoderm.

We have surveyed the early stages in the development and differentiation of cultured mouse embryos for plasminogen activator production. This enzyme is first detectable by the sixth equivalent gestation day. Thereafter, cultured blastocysts produce plasminogen activator with a biphasic time course: in the first phase, enzyme secretion rises to a maximum at about the eighth day and then decreases; a second phase, during which more enzyme accumulates, begins somewhat later and continues to at least the fifteenth day. By fractionating the blastocyst into its constituent cell types, we have identified the trophoblast as the cells responsible for the first phase of enzyme synthesis. The pattern of enzyme production by the trophoblast is closely correlated with the invasive period of these cells in vivo and implies that plasminogen activator is involved in embryo implantation. The second phase of plasminogen activator production is due to parietal endoderm, which initiates enzyme synthesis upon differentiation from the inner cell mass. The properties of the parietal endoderm suggest that plasminogen activator may participate in the migration of these cells and/or in the metabolism of Reichert's membrane which accompanies embryo growth. These results are consistent with the concept, deveolped from work on other cell types, that plasminogen activator may represent a generalized mechanism for tissue remodeling and cell migration.

Animals↗
PubMed1982

Nonhelical, fibronectin-binding basement-membrane collagen from endodermal cell culture.

A novel method of affinity chromatography on insolubilized collagen-binding fragments of fibronectin was utilized to isolate a random-coil collagenous protein from culture media of mouse teratocarcinoma-derived endodermal cells. These cells also produced another collagenous protein, which did not bind to fibronectin but could be isolated by differential salt precipitation. The affinity-purified collagen differs from its conventionally isolated counterpart in that it is not triple-helical in structure, its polypeptides are not disulfide-crosslinked and it has affinity for fibronectin in its native state. Both collagens resemble previously characterized type IV basement-membrane collagens with respect to their amino acid composition, cyanogen bromide peptides, chain size, immunological reactivity and tissue localization. The random-coil collagen is directly active in promoting the attachment of some lines of cells, but for attachment of the endodermal cells addition of fibronectin is required. This suggests that the presence of nonhelical, fibronectin-binding collagen may have biological significance in the interaction of cells with the extracellular matrix.

Amino Acids↗
PubMed1993

Apical expression of an antigen common to rabbit yolk sac endoderm and kidney proximal tubule epithelium.

The tissue distribution, molecular weight, and biochemical nature of an antigen detected by a mouse monoclonal antibody designated 283D3 and raised against rabbit visceral yolk sac endodermal cells, has been investigated. The antigen is located on the luminal side of apical tubules and large sub-apical vesicles in rabbit yolk sac endoderm and proximal kidney tubule epithelial cells. It is expressed in a similar polarised fashion in epithelial cells lining the epididymis. Western blotting showed the antigen to comprise proteins of molecular weight 330-380 kDa. The antigen has been affinity purified from yolk sac and kidney and is predominantly protein in nature with a small percentage of N-linked carbohydrate. In terms of tissue distribution and molecular weight it has close similarity to Heymann nephritis antigen but differs in not being confined to coated pits. Its function is not known, but the association with endocytic elements implies a possible role in non-specific protein absorption.

Animals↗
PubMed1991

Differentiation of aggregated murine P19 embryonal carcinoma cells is induced by a novel visceral endoderm-specific FGF-like factor and inhibited by activin A.

Aggregation of P19 embryonal carcinoma cells in the presence of a factor, secreted by the visceral endoderm-like cell line END-2, induces differentiation to cell types including visceral endoderm, mesoderm-derived muscle tissue and neurons. This factor is different from activin A, type beta transforming growth factors (TGF beta) and fibroblast growth factors (FGF) although its acid- and heat-lability and its stability in the presence of reducing agents resemble the properties of the FGFs. The END-2 factor is completely inhibited in its action by activin A. This inhibitory effect of activin A is not specific for the END-2 factor as retinoic acid (RA)-induced differentiation of aggregated P19 EC cells into neurons (10(-8) M RA) or mesoderm-derived muscle tissue (10(-9) M RA) is also completely inhibited by activin A. The results of this study suggest that the END-2 activity and activin A are intimately involved in the induction and regulation, respectively, of early differentiation processes in vertebrate embryogenesis.

Activins↗
PubMed1994

Localization of PDGF A and PDGFR alpha mRNA in Xenopus embryos suggests signalling from neural ectoderm and pharyngeal endoderm to neural crest cells.

In situ hybridization analysis of Xenopus laevis embryos reveals that mRNA encoding the platelet-derived growth factor alpha receptor (PDGFR alpha) is expressed in cephalic neural crest masses prior to migration from the future neural tube and during their migration into the visceral arches. The analysis of fluorescently labeled neural crest tissue transplanted to unlabeled host embryos demonstrates that neural crest cells are the only detectable source of PDGFR alpha mRNA within visceral arches. Transcripts encoding PDGF A are present in neural ectoderm, otic vesicle and pharyngeal endoderm. Their location suggests that PDGF A provides a signal, first from the neural epithelium and later from the otic vesicle and pharyngeal endoderm, to cephalic neural crest cells during their migration in the arch region.

Animals↗