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At least 19 recordsLinked to original sources
PubMed1998

[Juvenile pleomorphic parotid adenoma of embryonal structure].

Juvenile pleomorphic adenoma of the parotid gland represents an extremely rare tumour entity and is comparable to congenital tumours of the salivary glands concerning its embryonal structure. The clinical detection of the tumour in a 7-year-old girl does not exclude that the tumour had developed either earlier or immediately after the birth. The high cellularity and the evidence of primitive epithelial and myoepithelial cellular structures do not justify its classification as a malignant tumour. However the presence of embryonal tissue structures associated with the end of the third month of embryogenesis is characterized by more solid cell formations in partly verticulate arrangement. The absence of further differentiation into lobular structures and differentiated duct or acinic cell formations may be due to cell arrest. Differential diagnosis of juvenile pleomorphic adenoma must distinguished it from other congenital salivary gland tumours (e.g. congenital basal cell adenoma, hybrid basal cell adenoma-adenoid cystic carcinoma, sialoblastoma, salivary gland anlage tumour.

Adenoma, Pleomorphic↗
PubMed1987

Specific expression of the Hox 1.3 homeo box gene in murine embryonic structures originating from or induced by the mesoderm.

The murine Hox 1.3 homeo box-containing gene is expressed largely in mesoderm-derived or mesoderm-induced embryonal structures, as evidenced by in situ hybridization techniques. Expression is spatially limited to the thoracic region, specifically to components of segmental origin such as embryonal ribs and vertebrae and their precursors such as the equivalent sclerotomes, somites and somatic condensations. In addition, expression can be found in parts of embryonal lung, stomach tissue, gut and kidney, tissues whose formation is based on induction of region-specific mesoderm, as well as in some ectoderm-derived tissues. The expression is temporally controlled for the transcripts and can only be detected while the thoracic structures are being formed (days 8-13), but not at day 18 of gestation when the embryo is mature. These data suggest a role of Hox 1.3 gene in the generation of tissues derived from or induced by the embryonal mesoderm.

Animals↗
PubMed1999

The zebrafish bozozok locus encodes Dharma, a homeodomain protein essential for induction of gastrula organizer and dorsoanterior embryonic structures.

The dorsal gastrula organizer plays a fundamental role in establishment of the vertebrate axis. We demonstrate that the zebrafish bozozok (boz) locus is required at the blastula stages for formation of the embryonic shield, the equivalent of the gastrula organizer and expression of multiple organizer-specific genes. Furthermore, boz is essential for specification of dorsoanterior embryonic structures, including notochord, prechordal mesendoderm, floor plate and forebrain. We report that boz mutations disrupt the homeobox gene dharma. Overexpression of boz in the extraembryonic yolk syncytial layer of boz mutant embryos is sufficient for normal development of the overlying blastoderm, revealing an involvement of extraembryonic structures in anterior patterning in fish similarly to murine embryos. Epistatic analyses indicate that boz acts downstream of beta-catenin and upstream to TGF-beta signaling or in a parallel pathway. These studies provide genetic evidence for an essential function of a homeodomain protein in beta-catenin-mediated induction of the dorsal gastrula organizer and place boz at the top of a hierarchy of zygotic genes specifying the dorsal midline of a vertebrate embryo.

Animals↗
PubMed2002

mRNA expression profiling of laser microbeam microdissected cells from slender embryonic structures.

Microarray hybridization has rapidly evolved as an important tool for genomic studies and studies of gene regulation at the transcriptome level. Expression profiles from homogenous samples such as yeast and mammalian cell cultures are currently extending our understanding of biology, whereas analyses of multicellular organisms are more difficult because of tissue complexity. The combination of laser microdissection, RNA amplification, and microarray hybridization has the potential to provide expression profiles from selected populations of cells in vivo. In this article, we present and evaluate an experimental procedure for global gene expression analysis of slender embryonic structures using laser microbeam microdissection and laser pressure catapulting. As a proof of principle, expression profiles from 1000 cells in the mouse embryonic (E9.5) dorsal aorta were generated and compared with profiles for captured mesenchymal cells located one cell diameter further away from the aortic lumen. A number of genes were overexpressed in the aorta, including 11 previously known markers for blood vessels. Among the blood vessel markers were endoglin, tie-2, PDGFB, and integrin-beta1, that are important regulators of blood vessel formation. This demonstrates that microarray analysis of laser microbeam micro-dissected cells is sufficiently sensitive for identifying genes with regulative functions.

Animals↗
PubMed1983

[The Tae Yang (V) and Tou Mo (VG) meridians as vestiges of embryonic structures. Acupuncture as embryo reflex therapy: a new theory].

A new theory for the understanding of the therapeutic results of two channels of Chinese Acupuncture: Urinary Bladder (U.B.) and Tou Mo. It is possible to underline that these two channels represent in the adult the trace of anatomical structures present in the human embryo. The series of medial posterior branches at their skin output are the Yu points where the myotomic slides split in their epiaxial and hypoaxial parts (statural and kinetic muscles). Tou Mo channel is the adult trace of the embryonic primitive line.

Acupuncture Therapy↗
PubMed1995

Expression of serum albumin and of alphafetoprotein in murine normal and neoplastic primitive embryonic structures.

Alphafetoprotein (AFP), a major serum protein synthesized during the embryo-fetal and postnatal period (in the yolk sac, then in the liver), is also an oncoprotein. The intracellular presence of AFP and of serum albumin (SA) in normal and neoplastic neural crest and neural tube derivatives was previously demonstrated. In this work we have studied the comparative expression of AFP and SA in primitive neuroectoblastic structures of mouse embryos (6 and 7 days "post coitum") and mouse teratocarcinomas (derived from the PCC4 cell line). Using immunofluorescence technique, antibodies to SA gave a positive reaction in embryos of 7 days, while AFP was not detected during this period. By mRNA in situ hybridization, SA mRNA gave a strong signal in both 6 and 7 day embryos, whereas AFP mRNA gave a weak signal only in 7-day embryos. The distribution of SA and AFP and their mRNAs was investigated in primitive neuroectoblastic structures of the teratocarcinomas by in situ hybridization and immunostaining. Only SA protein was detectable by immunostaining. SA mRNA gave a strong signal in differentiating structures as well as in undifferentiated cell clusters. AFP mRNA was observed only in differentiating structure. Dot-blot hybridization indicated that the level of SA transcripts was at least 6-fold higher than that of AFP transcripts in the teratocarcinomas investigated. In teratocarcinoma-bearing mice injected intraperitoneally with 125I-radiolabeled SA and AFP, significant accumulations of both SA and AFP were demonstrated in the tumors, SA being about 3-fold higher than that of AFP after normalization to quantity of uptake in liver. External in vivo photoscanning confirmed this relationship of accumulated radiolabeled proteins. The last observation could be useful in vivo for diagnosis of teratocarcinoma. We conclude that the expression of SA relative to AFP and the external cellular uptake of SA relative to AFP are similar in normal embryonic developing tissues and in the corresponding morphologically neoplastic tissues of the teratocarcinomas. The same SA:AFP relationship constitutes an oncofetal marker of primitive neuroectoblastic structures.

Animals↗
PubMed1997

The murine homologue of HIRA, a DiGeorge syndrome candidate gene, is expressed in embryonic structures affected in human CATCH22 patients.

A wide spectrum of birth defects is caused by deletions of the DiGeorge syndrome chromosomal region at 22q11. Characteristic features include cranio-facial, cardiac and thymic malformations, which are thought to arise form disturbances in the interactions between hindbrain neural crest cells and the endoderm of the pharyngeal pouches. Several genes have been identified in the shortest region of deletion overlap at 22q11, but nothing is known about the expression of these genes in mammalian embryos. We report here the isolation of several murine embryonic cDNAs of the DiGeorge syndrome candidate gene HIRA. We identified several alternatively spliced transcripts. Sequence analysis reveals that Hira bears homology to the p60 subunit of the human Chromatin Assembly Factor I and yeast hir1p and Hir2p, suggesting that Hira might have some role in chromatin assembly and/or histone regulation. Whole mount in situ hybridization of mouse embryos at various stages of development show that Hira is ubiquitously expressed. However, higher levels of transcripts are detected in the cranial neural folds, frontonasal mass, first two pharyngeal arches, circumpharyngeal neural crest and the limb buds. Since many of the structures affected in DiGeorge syndrome derive from these Hira expressing cell populations we propose that haploinsufficiency of HIRA contributes to at least some of the features of the DiGeorge phenotype.

Alternative Splicing↗
PubMed2003

The murine Nck SH2/SH3 adaptors are important for the development of mesoderm-derived embryonic structures and for regulating the cellular actin network.

Mammalian Nck1 and Nck2 are closely related adaptor proteins that possess three SH3 domains, followed by an SH2 domain, and are implicated in coupling phosphotyrosine signals to polypeptides that regulate the actin cytoskeleton. However, the in vivo functions of Nck1 and Nck2 have not been defined. We have mutated the murine Nck1 and Nck2 genes and incorporated beta-galactosidase reporters into the mutant loci. In mouse embryos, the two Nck genes have broad and overlapping expression patterns. They are functionally redundant in the sense that mice deficient for either Nck1 or Nck2 are viable, whereas inactivation of both Nck1 and Nck2 results in profound defects in mesoderm-derived notochord and embryonic lethality at embryonic day 9.5. Fibroblast cell lines derived from Nck1(-/-) Nck2(-/-) embryos have defects in cell motility and in the organization of the lamellipodial actin network. These data suggest that the Nck SH2/SH3 adaptors have important functions in the development of mesodermal structures during embryogenesis, potentially linked to a role in cell movement and cytoskeletal organization.

Actins↗
PubMed1989

Dating the early pregnancy by sequential appearance of embryonic structures.

A total of 97 transvaginal scans were performed from 4 to 12 weeks' gestation in normal and accurately dated gestations. The sequential appearance of six structures were examined: (1) the gestational sac only was present during week 4; (2) the yolk sac appeared in week 5; (3) the fetal pole with detectable heart motion was first seen in week 6; (4) the single unpartitioned ventricle in the brain marked week 7; (5) the falx cerebri appeared during week 9; and (6) the appearance and the disappearance of the physiologic midgut herniation were seen in week 8 and week 11, respectively. Inasmuch as the time in gestation at which these structures appear characterizes the gestational age more than any measurement at this age, we propose a practical method to determine the correct gestational age in early first-trimester pregnancy.

Brain↗
PubMed1997

Hypochord, an enigmatic embryonic structure: study of the axolotl embryo.

The hypochord of the axolotl embryo is first visible at an early tailbud stage, forming a rod-like structure, situated immediately under the notochord. A profusion of extracellular matrix fibrils is attached to the dorsolateral regions of the hypochord, linking it with the somites. A basal lamina develops around the hypochord, indicating an epithelial type of cell differentiation. Abundant rough endoplasmic reticula in the hypochord cells suggest lively synthetic activity. Prospective endoderm cells were vitally labeled with the lipophilic dye 1,1-dioctadecyl-3,3,3',3'-tetramethylindodicarbocyanine perchlorate (DiD) at the gastrula stage. Cells labeled with the dye were later found in the hypochord as well as in the gut endoderm. This shows that the hypochord is of endodermal origin, contrary to recent suggestions that the hypochord is of mesodermal origin, but consistent with histological data. After about 8 days of existence, the hypochord disappears. Experimental results, using an apoptosis detection kit, indicate that the hypochord cells may disintegrate by a type of apoptotic cell death. The close association between the hypochord and developing dorsal aorta suggests that the hypochord could be involved in the positioning of the dorsal aorta, which forms under it.

Ambystoma↗
PubMed1988

A method for predicting the cranio-caudal position of secondary embryonic structures.

The morphogenetic events that give rise to a specific body pattern have to date avoided extensive elucidation. Extant models of pattern formation have dealt almost exclusively with the "primary patterning" of structures in the embryo. These "universal" models fail to explain many morphological conditions, such as the simultaneous change in position of the limbs, celom, mesonephros, and umbilical artery relative to the somites as a result of a single mutation. In the present paper, we propose that the relation between two non-periodic waves may function to determine the position of "secondary structures", such as the limbs, in the embryo, relative to primary structures such as the somites. We propose that if two morphogenetic events are initiated at different times from the same region of the embryo, and are progressing in a cranio-caudal sequence at different rates, then the location of a given structure along the body axis can be described as a function of the two events. Applications and predictions based on the proposal are presented. Evidence from observations of morphogenetic events in the chick embryo, which tend to support the model, are also presented.

Animals↗
PubMed1994

Sonic hedgehog: a key mediator of anterior-posterior patterning of the limb and dorso-ventral patterning of axial embryonic structures.

Sonic hedgehog is expressed in several sites during embryogenesis which are known to be important in directing the development of neighbouring tissues, including Hensen's node, the notochord, the floor plate of the neural tube, and the posterior of the limb bud. A unity in signalling mechanisms utilized by these inducers was first indicated because they all can provide a source of limb polarizing activity, assayed by grafting into the anterior of a limb bud. The hypothesis that they share a common signal is substantiated by the fact that they all express Sonic. Moreover, ectopic expression of Sonic in vivo suggests that it is responsible for the polarizing activity of the ZPA and plays an important role in dorso-ventral patterning of the spinal cord. The isolation of Sonic heralds a new era in the investigation of the molecular mechanisms of these key inductive interactions in vertebrate development.

Amino Acid Sequence↗
PubMed2004

Carbonic anhydrases in chick extra-embryonic structures: a role for CA in bicarbonate reabsorption through the chorioallantoic membrane.

The villus cavity cells, a specific cell type of the chick chorioallantoic membrane, express both cytosolic carbonic anhydrase in their cytoplasm and HCO3(-)/Cl(-) anion exchangers at their basolateral membranes. By immunohistochemical analysis, we show here that villus cavity cells specifically react with antibodies directed against the membrane-associated form of carbonic anhydrase, CAIV. Staining is restricted to the apical cell membranes, characteristically invaginated toward the shell membrane, as well as to endothelia of blood vessels present in the mesodermal layer. The occurrence of a membrane-associated CA form at the apical pole of villus cavity cells, when definitively confirmed, would be fairly consistent with the role proposed for these cells in bicarbonate reabsorption from the eggshell so to prevent metabolic acidosis in the embryo during development.

Absorption↗