(n.) An elastic cartilagelike rod which is developed beneath the medullary groove in the vertebrate embryo, and constitutes the primitive axial skeleton around which the centra of the vertebrae and the posterior part of the base of the skull are developed; the chorda dorsalis. See Illust. of Ectoderm.
Example Sentences:
(1) The histochemical study of the LDH in the Trout embryo during the early organogenesis shows a specific localization in notochord cells, in mesodermic cells of the terminal knob and in some prosencephalic neuroblasts.
(2) The notochord, which is composed of a stack of flat cells surrounded by a connective tissue sheath, elongates dramatically and begins straightening between stages 21 and 25.
(3) Autoradiographic studies show that tritiated proline is taken up by notochordal cells and secreted to the extracellular space where label is associated with basal lamina, microfibrils and ground substance.
(4) Metabolic events in somites related to hyaluronic acid are not influenced by the notochord.
(5) The establishment of myeloschisis was followed by local separation of the notochord from an open area of neural tube, but not by overgrowth of neural tissue.
(6) By 7 days, notochordal uptake is markedly diminished, and no uptake of isotope occurs from 8 days onward.
(7) It first forms on the lateral portion of the neuroepithelium of the neural folds and then extends ventrally into the region adjacent to the notochord; (ii) BL becomes continuous beneath the epidermal ectoderm (EE) that overlies the NC cell region only during the terminal stages of NC cell emigration; (iii) BL does not form over the dorsal portion of the neural tube until NC emigration is terminated; and (iv) the morphology of the BL changes as development proceeds.
(8) Although they are presumed to arise from congenital notochordal remnants, it is rare for these tumors to present in childhood.
(9) Six chordomas, ten fetal notochords and eight adult notochords were stained for keratin, vimentin, GFAP, desmin, CEA, EMA and s-100 protein.
(10) A "diffuse pattern" that was seen in the histological appearance of 4 cases of the chordoma, including 2 cases with metastases, was not observed in the notochord and was considered to indicate the malignant nature of such chordoma.
(11) The results lead to the assumption that the early embryos already possess cholinergic receptors, probably located in the notochord.
(12) Adjacent to the caudal half of each somite, these cells penetrated no further than the myosclerotomal border, but opposite the rostral somite half, they were found next to the sclerotome almost as far ventrally as the notochord.
(13) These results indicate that 1) Engrailed-2 expression is suppressed in the most ventral neural tube owing to induction of the floor plate by the notochord, and 2) that the presence of an underlying notochord is not required for correct rostrocaudal expression, suggesting that multiple pathways act in the patterning of the rudiment of the central nervous system.
(14) Neural induction through the presumptive notochord was tested by means of the sandwich method.
(15) The notochord and neural tube are well developed by 3 days and surrounded by sclerotome, myotome, and dermatome cells.
(16) Minute fragments of the notochord of Balanoglossus sp.
(17) Glycosaminoglycans (GAG) are found primarily in the dorsal fin and in the ECM surrounding the notochord.
(18) Based on these facts, it is to be concluded that it is not the inducer of notochord, but the surrounding mesenchyme that is of primary importance for the determination of the types of neural tissue.
(19) A floor plate-specific chemoattractant was used as a marker to examine the role of the notochord in avian floor plate development.
(20) 2G9 was used to show that both notochord and somites are capable of neural induction, and the stimulus is present as late as stage 22.
Structure
Definition:
(n.) The act of building; the practice of erecting buildings; construction.
(n.) Manner of building; form; make; construction.
(n.) Arrangement of parts, of organs, or of constituent particles, in a substance or body; as, the structure of a rock or a mineral; the structure of a sentence.
(n.) Manner of organization; the arrangement of the different tissues or parts of animal and vegetable organisms; as, organic structure, or the structure of animals and plants; cellular structure.
(n.) That which is built; a building; esp., a building of some size or magnificence; an edifice.
Example Sentences:
(1) The findings indicate that there is still a significant incongruence between the value structure of most family practice units and that of their institutions but that many family practice units are beginning to achieve parity of promotion and tenure with other departments in their institutions.
(2) The influence of the various concepts for the induction of lateral structure formation in lipid membranes on integral functional units like ionophores is demonstrated by analysing the single channel current fluctuations of gramicidin in bimolecular lipid membranes.
(3) We have determined the genomic structure of the fosB gene and shown that it consists of 4 exons and 3 introns at positions also found in the c-fos gene.
(4) Structure assignment of the isomeric immonium ions 5 and 6, generated via FAB from N-isobutyl glycine and N-methyl valine, can be achieved by their collision induced dissociation characteristics.
(5) The fine structure of neurofibrillary tangles in the hippocampal gyrus, substantia nigra, pontine nuclei and locus coeruleus of the brain was postmortem studied in a case of progressive supranuclear palsy.
(6) Life expectancy and the infant mortality rate are considered more useful from an operational perspective and for comparisons than is the crude death rate because they are not influenced by age structure.
(7) It has been generally believed that the ligand-binding of steroid hormone receptors triggers an allosteric change in receptor structure, manifested by an increased affinity of the receptor for DNA in vitro and nuclear target elements in vivo, as monitored by nuclear translocation.
(8) Immunocytochemistry was used to visualize cytoskeletal structures and to assay selective disruption of neurofilaments by acrylamide.
(9) The quaternary structure of ribonucleotide reductase of Escherichia coli was investigated, with the use of purified B1 and B2 proteins and bifunctional cross-linking agents.
(10) Structural peculiarities in tubulin polymorphism are considered.
(11) We report a series of experiments designed to determine if agents and conditions that have been reported to alter sodium reabsorption, Na-K-ATPase activity or cellular structure in the rat distal nephron might also regulate the density or affinity of binding of 3H-metolazone to the putative thiazide receptor in the distal nephron.
(12) It is likely that trunk mobility is necessary to maintain integrity of SI joint and that absence of such mobility compromises SI joint structure in many paraplegics.
(13) Fluorination with [18F]acetylhypofluorite yields 6-[18F]fluoro-L-dopa with 95% radiochemical purity; fluorination of the same substrate with [18F]F2 yields a mixture of all three structural isomers in a ratio of 70:16:14 for 6-, 5-, and 2-fluoro compounds.
(14) But the wounding charge in 2010 has become Brown's creation of a structural hole in the budget, more serious than the cyclical hit which the recession made in tax receipts, at least 4% of GDP.
(15) The aetiological factors concerned in the production of paraumbilical and epigastric hernias have been reviewed along structural--functional lines.
(16) The disassembly of the synthetase complex is consistent with the structural model of a heterotypic multienzyme complex and suggests that the complex formation is due to the specific intermolecular interactions among the synthetases.
(17) In addition to the phase diagrams reported here for these two binary mixtures, a brief theoretical discussion is given of other possible phase diagrams that may be appropriate to other lipid mixtures with particular consideration given to the problem of crystalline phases of different structures and the possible occurrence of second-order phase transitions in these mixtures.
(18) The structures of 1 and 2 were established mainly on the basis of nmr spectroscopic data.
(19) Determination of the primary structure for factor V has provided the basis for examination of structure-function relationships.
(20) Aside from these characteristic findings of HCC, it was important to reveal the following features for the diagnosis of well differentiated type of small HCC: variable thickening or distortion of trabecular structure in association with nuclear crowding, acinar formation, selective cytoplasmic accumulation of Mallory bodies, nuclear abnormalities consisting of thickening of nucleolus, hepatic cords in close contact with bile ducts or blood vessels, and hepatocytes growing in a fibrous environment.