(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.
Vertebrae
Definition:
(pl. ) of Vertebra
Example Sentences:
(1) It is concluded that during exposure to simulated microgravity early signs of osteoporosis occur in the tibial spongiosa and that changes in the spongy matter of tubular bones and vertebrae are similar and systemic.
(2) It is suggested that the Japanese may have lower trabecular bone mineral density than Caucasians but may also have a lower threshold for fracture of the vertebrae.
(3) The various changes were accompanied by a marked reduction in the overall wet weight of the vertebrae.
(4) The BMD of the 2nd to 4th lumbar vertebrae was measured and the mean density presented as g cm-2.
(5) All the vertebrae were agenetic below the thoracic segments in the other rat fetus.
(6) Neusticosaurus species are easiest separated by their number of presacral vertebrae.
(7) This was followed by a gradual density increase such that by 1 year postoperatively, in 60% of the subjects, the density of these vertebrae was higher than the preoperative level.
(8) The characteristic injuries were compression wedge-shaped fractures, multiple fractures of the vertebrae, comminuted and traumatic spondylolistheses and dislocation fractures.
(9) They make it possible to dissect, by spending minimal time and making less efforts, the vertebral canal both within several vertebrae and its nearly full length, providing a wide view of the spinal cord, rootlets, and intervertebral ganglia.
(10) The Authors describe the moniliform structure of dorsal aorta of the Cyprinus carpio L., which has successive swellings and constrictions, strictly corresponding to each vertebra.
(11) He also had multiple follicular and papillary thyroid carcinomas with a metastatic lesion in the lumbar vertebrae.
(12) In older children, there were a low vertebral signal and disappearance of the disc-vertebra borders on T1-weighted images and a high vertebral signal with a decreased and flattened disc signal on T2-weighted images.
(13) Hyperthermia was applied in the region of the vertebral column between the cervical vertebrae 5 and thoracic 2, using a ring-shaped applicator operating at a microwave frequency of 434 MHz.
(14) The authors report on their experience with 23 patients with destructive disease of the vertebrae.
(15) In 20 patients, vertebral deformities were limited to 1 or 2 mid-thoracic vertebrae, and the mean CaBI values for these 20 patients was 0.81 (0.15), equal to that for patients without any vertebral deformity.
(16) Both conditions are inherited and characterised by malformed thoracic and lumbar vertebrae.
(17) The injured vertebra is grafted through the pedicle, giving security against late collapse after device removal.
(18) The authors describe two types of pelvic obliquity--total pelvic obliquity in which the sacrum is the lowest vertebra of the lumbar curve and subtotal pelvic obliquity in which there is some compensation between L5 and the sacrum.
(19) Although anterior and posterior traumatic displacement of cervical vertebrae are commonly noted, and the devastating neurological deficits associated with these injuries have been amply defined, lateral displacement with fractures has been rarely recognized, and the clinical significance of this injury has been overlooked.
(20) The T-1 nerve root obstructs posterolateral access to the T-1 vertebra, necessitating an inferolateral approach underneath the T-1 nerve root axilla.