(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.
Epidermis
Definition:
(v. t.) The outer, nonsensitive layer of the skin; cuticle; scarfskin. See Dermis.
(v. t.) The outermost layer of the cells, which covers both surfaces of leaves, and also the surface of stems, when they are first formed. As stems grow old this layer is lost, and never replaced.
Example Sentences:
(1) 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.
(2) A comparison between TPA and cytokeratins was also made by immunoblotting which revealed immunoreactivity of antibodies to TPA with cytokeratin polypeptides of different species (man, mouse) and organs (epidermis, liver), particularly with the cytokeratin component 8 of human liver and the related component A of mouse liver.
(3) The enzyme profile of the epidermis was investigated in relation to depth.
(4) It increased linearly in both the epidermis and dermis, reaching nearly 100% 24 hr following its injection on Day 8.
(5) UVB irradiation augmented the beta-adrenergic adenylate cyclase response of pig skin epidermis in vitro.
(6) The kinetics of both the solube and particulate enzymes from epidermis of some elderly patients with either diabetes or ischaemia showed some differences from the kinetics of enzymes from healthy epidermis from younger individuals.
(7) These results indicate that uninvolved psoriatic epidermis has an increased capacity to metabolize free AA into 12-lipoxygenase products.
(8) Besides the rough, wrinkled, and brown or black surface of the fingertips, microwrinkles of the epidermis occur on the skin ridges, which have so far not been described.
(9) At an ultrastructural level, 15-1 immunogold-labeling in the epidermis was confined to the surface of cells exhibiting Birbeck granules.
(10) The synthesis of uPA as a precursor with reduced enzymatic activity as well as decreased affinity for inhibitors is likely to be a mechanism by which normal epidermis regulates plasminogen activation in vivo.
(11) The bone marrow derivation of dThy-1+EC is now well established: dThy-1+EC carry Ly-5 determinants whose expression is restricted to cells of the hemopoietic differentiation pathway, and studies using Thy-1-disparate radiation bone marrow chimeras have revealed the presence of donor-type Thy-1+ cells within the epidermis; by immunoelectron microscopy, these cells represent dThy-1+EC.
(12) Exposure of neutrophils to AS resulted in deactivation to AS but not to Escherichial coli or Staphylococcus epidermis culture filtrate.
(13) The delta-PKC-like kinase of mouse epidermis (p82-kinase) was down-regulated after topical application of 12-O-tetradecanoylphorbol-13-acetate (TPA) to mouse skin.
(14) The purpose of this report is to present the kinetics of reduction of epidermal mass following the production of the epidermal hyperplasia as the epidermis returns to its normal thickness during the period of regression.
(15) Immunoreactivity was restricted to the periderm and intermediate layers of fetal epidermis at 55 d of gestation, when the first wave of wool follicles are initiated.
(16) In hatched larvae around developmental stage 46, strong expression of 2NI-36 was observed in several tissues including the vascular endothelium, the pigmented epithelium and the inner layer of skin epidermis.
(17) Our results show that two major types of terminally differentiating keratinocytes can be distinguished in human epidermis, i.e.
(18) This results suggest the presence of structural abnormalities in epidermis of EB simplex.
(19) By contrast, epidermal Langerhans cell (LC) HLA-DR and T6 expressions in normal epidermis were greatly reduced by an identical dose of UVB.
(20) This calcium-binding protein was not in skin epidermis, but was confined to the dermal layer.