(n.) The external skin or outer layer of an animal or plant, this being formed in an animal from the epiblast. See Illust. of Blastoderm.
Example Sentences:
(1) Here we report direct measurements of protein kinase C (PKC) activity in uninduced ectoderm, and in neuroectoderm shortly after induction by the involuting mesoderm, in Xenopus laevis embryos.
(2) The Notch locus in Drosophila encodes a transmembrane protein required for the determination of cell fate in ectodermal cells.
(3) The factor was tested on Triturus alpestris by the implantation method, and on isolated ectoderm of Xenopus laevis in solution.
(4) Evx-1 RNA is first detected shortly before the onset of gastrulation in a region of ectoderm containing cells that will soon be found in the primitive streak.
(5) Cells falling off from ectoderm were observed in normally developing gastrulae of the newt, Cynops pyrrhogaster, in light microscopic examination.
(6) Anhidrotic ectodermal dysplasia is characterized by an absence of seromucous glands in the oropharynx and tracheobronchial tree, making children with this disease prone to viral and bacterial respiratory infections.
(7) The positive reaction for keratin and vimentin confirmed the presence of ectodermal and mesodermal elements respectively in the tumor.
(8) Examination of the two types of tissue fragments revealed that IS-treated ICMs almost invariably retained viable endoderm cells whereas MS-isolated ectoderms did so only exceptionally.
(9) In the present study, ectodermal explants from Xenopus blastulae were shown to have high affinity binding sites for 125I-aFGF (Kd = 1.4 X 10(-10) M).
(10) Ectoderm from Cynops pyrrhogaster reacts like that of Ambystoma when exposed to LiCl, but like Triturus ectoderm it is insensitive to cyclic nucleotides.
(11) Several mouse mutants in the distal region of the mouse t-complex affecting blastocyst and embryonic ectoderm formation also map to this region.
(12) PTN mRNA was also strongly expressed in the basal layers of the tongue epithelium, which is the only epithelium and ectodermal derivative to express PTN mRNA, and this only after birth.
(13) These genes encode membrane proteins with epidermal growth factor repeats and are essential in the decision of an embryonic ectodermal cell to take on the fate of neuroblast or epidermoblast.
(14) We have found that competence of the ectoderm to respond to induction is lost at the same early neurula stage for all three marker genes.
(15) Multiple hamartoma syndrome, also known as Cowden's disease, is a rare genodermatosis with multiple organ system involvement affecting tissues derived from ectodermal, endodermal, and mesodermal tissue layers.
(16) From the right wing bud of stage 19 and 20 (HH) embryos the rim ectoderm was removed in four ways: all of the rim, the anterior third, the middle third (most of the A.E.R.
(17) During feather follicle formation, N-CAM was expressed in the dermal papilla and was closely apposed to the L-CAM-positive papillar ectoderm, while the dermal papilla showed no evidence of laminin or fibronectin.
(18) Initially each primordium forms a shallow depression in the ectodermal surface.
(19) From stage 110 on, a basement membrane differentiates beneath a one-cell thick subperipheral layer, which thus becomes the ectodermal basal layer, the prospective epidermal basal layer.
(20) CAT mRNA was observed in gut, mesenchyme cells and oral ectoderm in these embryos.
Epithelium
Definition:
(n.) The superficial layer of cells lining the alimentary canal and all its appendages, all glands and their ducts, blood vessels and lymphatics, serous cavities, etc. It often includes the epidermis (i. e., keratin-producing epithelial cells), and it is sometimes restricted to the alimentary canal, the glands and their appendages, -- the term endothelium being applied to the lining membrane of the blood vessels, lymphatics, and serous cavities.
Example Sentences:
(1) By electrophoresis and scanning densitometry, actin was found to constitute about 4% to 6% of the total cellular protein in the human corneal epithelium.
(2) One hour after direct mechanical cardiomassage (DMCM) a moderately pronounced edema of the intercellular spaces in the basal compartment of the seminiferous epithelium, normal content of lactate and succinate dehydrogenases, and a certain decrease in the activity of glucose-6-phosphate dehydrogenases and NAD- and NADP-diaphorases were noted.
(3) The subcellular distribution of sialyltransferase and its product of action, sialic acid, was investigated in the undifferentiated cells of the rat intestinal crypts and compared with the pattern observed in the differentiated cells present in the surface epithelium.
(4) An inflammatory process than occurs in the airways that is characterized by an influx of eosinophils and neutrophils into the airway epithelium and bronchial fluids.
(5) Data is available to support the early influences of enamel organ epithelium upon a responding mesenchyme in the determination of dental morphogenetic fields (Dryburg, 1967; Miller, 1969).
(6) The epithelium of Brunner's gland stained intensely with Ricinus communis agglutinin-I (RCA-I), succinylated-WGA (S-WGA) and wheat-germ agglutinin (WGA), moderately with Bandeirea simplicifolia agglutinin-I (BS-I), Concanavalia ensiformis agglutinin (Con A) peanut agglutinin (PNA) and Ulex europaeus agglutinin-I (UEA-I) and occasionally with Dolichos biflorus agglutinin (DBA), Lens culinaris agglutinin (LCA) and soybean agglutinin (SBA).
(7) Proliferating cells were abundant and scattered throughout the stratified epithelium before the appearance of villi.
(8) Two lectins, wheat germ agglutinin (WGA) and peanut agglutinin (PNA), were used to compare domains within the interphotoreceptor matrices (IPM) of the cat and monkey, two species where the morphological relationship between the retinal pigment epithelium (RPE) and photoreceptors is distinctly different.
(9) In the kidneys the index of incorporation inthe epithelial cells of the renal cortex was 7.5-fold and in the brain cortex epithelium 15-fold as increased, respectively.
(10) This case is unusual in that it demonstrated no malignant epithelium beyond that of a borderline tumor, but met the criteria of malignancy because of its invasiveness and metastasis.
(11) Volumetric ratio between the thyroid epithelium and colloid did not changed.
(12) Increased amounts of laminin in the basal epithelium of the cornea and of collagen type III in the stroma and subepithelial components of the stroma were observed.
(13) The observed staining indicated that the epithelium of the external auditory meatus has a pattern of keratin expression typical of epidermis in general and the epithelium of the middle ear resembles simple columnar epithelia.
(14) Hexokinase, phoshofructokinase, and aldolase appear to be rate-limiting in normal cervix epithelium; however, since the increase in activity of the first two in cancers was least of all the glycolytic enzymes, redundant enzyme synthesis probably occurs in the malignant cell for the enzymes catalysing reversible reactions.
(15) The ampullar epithelium showed similar changes, but to a lesser extent.
(16) Tunnel-like formations at different depths of the oral epithelium contained higher numbers of bacteria than those seen on the adjacent oral surface.
(17) Luminal and myoepithelial cells have been separated from normal adult human breast epithelium using fluorescence activated cell sorting.
(18) Changes in protein phosphorylation induced by phagocytic challenge were identified in cultured rat retinal pigment epithelium (RPE) following exposure to isolated rat rod outer segments (ROS) or to polystyrene latex microspheres (PSL).
(19) This may be because the epithelium restricts diffusion of the drug or due to the production of a non-prostanoid factor which inhibits smooth muscle responsiveness.
(20) 4 patients (4%) were found to have metaplastic changes of the lining epithelium.