Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “ECTODERM”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 793 records · Page 44Linked to original sources
PubMedDate not supplied

Increased tear evaporation in a patient with ectrodactyly-ectodermal dysplasia-clefting syndrome.

PURPOSE: To describe the tear function and ocular surface disorders in a patient with ectrodactyly-ectodermal dysplasia-clefting (EEC) syndrome. METHODS: Routine ophthalmic examinations were performed, including slit-lamp biomicroscopy, anterior segment photography including transillumination photos of the lids, Schirmer tests I and II, tear film break-up time (BUT) assessment, corneal fluorescein staining, DR-1 tear film lipid layer interferometry, and tear evaporation rate measurements. RESULTS: Slit-lamp examination revealed conjunctival hyperemia, superficial punctate keratopathy, and corneal leucoma with neovascularization. Although the Schirmer test values were within normal limits, the BUT value was 0 s in both eyes. Transillumination of the lids showed the absence of meibomian glandular structures. DR-1 tear film lipid layer interferometry results were dry eye grade 5 with an irregular tear film, areas of corneal surface exposure, and several dry spots. The tear evaporation rate was elevated and was measured as 6.98 x 10(-7) g/cm2 per second (normal, 4.1 +/- 1.4 x 10(-7) g/cm2 per second). CONCLUSION: The ocular surface disorder and shortened BUT in EEC syndrome were attributed to the absence of meibomian glands, leading to lipid layer deficiency in the tear film with a concomitant increase in tear evaporation.

Adolescent↗
PubMed1991

Subtle signs of prenatal maldevelopment of the hand ectoderm in schizophrenia: a preliminary monozygotic twin study.

Genes that predispose to psychosis may act by making individuals more vulnerable to the disruptive effects of various prenatal insults. Fetal organogenesis is mostly completed in the first prenatal trimester. The second trimester is a critical period of massive neuronal migration from the periventricular germinal matrix to the cortex. A peripheral appendage developing simultaneously with this neural migration to the cortex is the distal upper limb. The ectodermal cells of the fetal upper limb migrate to form the hand skin during the fourth and fifth months of gestation (first two-thirds of the second prenatal trimester). Discrepancies in hand morphology between two identical (monozygotic [MZ]) co-twins may be temporal markers, that is, the "fossilized" evidence of various ischemic and other nongenetic insults that may have affected one fetus more than his MZ co-twin during that early part of the second trimester. In twins, prenatal insults (e.g., ischemia) frequently do not affect both co-twins to the same extent, so we examined seven putative markers of prenatal injury to the hand in 24 MZ twin pairs discordant for schizophrenia or delusional disorder. Compared with well co-twins, the affected co-twins had significantly higher total scores of fourth- and fifth-month dysmorphological hand anomalies.

Delusions↗
PubMed1983

Spatial analysis of limb bud myogenesis: elaboration of the proximodistal gradient of myoblasts requires the continuing presence of apical ectodermal ridge.

Myogenic tissue from embryonic chick wing and leg buds is composed of several subpopulations of myoblasts. These clonally distinct subpopulations first appear at different developmental stages, and are distributed differently along the proximo-distal axis of the buds, giving the appearance of a gradient of myoblast cell types. This myoblast distribution pattern has been utilized to investigate the dependence of muscle tissue outgrowth and development on the presence of the apical ectodermal ridge (AER). Wing buds which have had the AER removed at stages 17-18 (2 days) subsequently develop normal proximal regions, but fail to elaborate skeletal structures distal to the humerus. The myoblast pattern of operated buds is also normal proximally, but distal portions of the pattern are not observed. Removal of the AER at stage 20 (3 days) results in buds which develop slightly more distal skeletal structures and the coinciding portions of the myoblast pattern, but in which the more distal portions of the normal myoblast gradient are truncated. These data suggest that elaboration of the myogenic pattern in early limb buds is dependent on the continuing presence of the AER, and that early removal of the AER leads to the subsequent cessation of myoblast pattern specification.

Animals↗
PubMed1984

Avian scale development. X. Dermal induction of tissue-specific keratins in extraembryonic ectoderm.

Epidermal-dermal tissue interactions regulate morphogenesis and tissue-specific keratinization of avian skin appendages. The morphogenesis of scutate scales differs from that of reticulate scales, and the keratin polypeptides of their epidermal surfaces are also different. Do the inductive cues which initiate morphogenesis of these scales also establish the tissue-specific keratin patterns of the epidermis, or does the control of tissue-specific keratinization occur at later stages of development? Unlike feathers, scutate and reticulate scales can be easily separated into their epidermal and dermal components late in development when the major events of morphogenesis have been completed and keratinization will begin. Using a common responding tissue (chorionic epithelium) in combination with scutate and reticulate scale dermises, we find that these embryonic dermises, which have completed morphogeneis, can direct tissue-specific stratification and keratinization. In other words, once a scale dermis has acquired its form, through normal morphogenesis, it is no longer able to initiate morphogenesis of that scale, but it can direct tissue-specific stratification and keratinization of a foreign ectodermal epithelium, which itself has not undergone scale morphogenesis.

Animals↗
PubMed1984

Migration of I-cells from ectoderm to endoderm in Hydra attenuata Pall (Cnidaria, Hydrozoa) and their subsequent differentiation.

The cellular composition of isolated ecto- and endoderm of the gastric column of Hydra attenuata Pall were recorded qualitatively and quantitatively. The endoderm contains a small population of I-cells ("basal cells") which give rise to the endodermal neurons. The recombination of live ecto- and endoderm, one of which had previously been [3H]thymidine labeled, revealed that the endodermal I-cells and their neural derivatives originate from ectodermal I-cells which migrate across the mesoglea. No other cell types were found to pass from one cell layer to the other. The experiments support the idea that the endodermal gland cells constitute an autoreproductive cell line independent of the pluripotent I-cells.

Animals↗
PubMed1986

Cell proliferation in the ectoderm of the Xenopus embryo: development of substratum requirements for cytokinesis.

The requirements for cell division in ectodermal blastomeres of the early Xenopus embryo were studied. Isolated blastomeres divide autonomously on nonadhesive agar in a simple salt solution up to the midblastula stage. After the midblastula transition, cell-cell contact is required for blastomere division. In isolated blastomeres of that stage, cytokinesis fails, but nuclear division continues normally for some time. Cell-cell contact as a prerequisite for blastomere division can be replaced by culturing blastomeres on an appropriate substratum. Clonal growth of isolated blastomeres is supported by a variety of protein substrata, indicating rather unspecific substratum requirements. Different substrata which do not support blastomere division can affect different steps in cytokinesis.

Animals↗
PubMed1986

Differences in the histogenesis and keratin expression of avian extraembryonic ectoderm and endoderm recombined with dermis.

The responses of the chorionic ectoderm and allantoic endoderm (from 8-day chick embryos) to dermal induction were compared through tissue recombinants grafted onto the chorioallantoic membrane. The chorionic epithelium formed the appropriate epidermis with a fully developed stratum corneum in response to both spur and scutate scale dermises. Analysis of these recombinant epidermal tissues by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) demonstrated that tissue-specific expression of the alpha (alpha) and beta (beta) keratin polypeptides occurred. In addition, indirect immunofluorescence studies with antisera to alpha or beta keratins showed that the beta stratum, which characterizes the epidermis of spurs and scutate scales, was formed, and the alpha keratins were distributed as in the normal epidermal tissues. In contrast, although the allantoic endoderm became stratified in association with either spur or scutate scale dermis, a stratum corneum with a beta stratum did not develop. SDS-PAGE analysis demonstrated that while the characteristic beta keratins of scutate scales and spur were not detected, most of the alpha keratins normally elaborated by these structures were present, suggesting that even without histogenesis of a stratum corneum the expression of alpha keratins of endoderm could be regulated in a tissue-specific manner by dermis. This study also demonstrated that there are differences in the abilities of the chorionic and allantoic epithelia to respond to the same dermal cues, which may reflect earlier restrictions in their developmental potentials.

Allantois↗
PubMed1988

Developmental origin of segmental differences in the leech ectoderm: survival and differentiation of the distal tubule cell is determined by the host segment.

The body plan of the adult leech is metameric, with each hemisegmental complement of ectodermal and mesodermal tissues being produced from a set of seven serially repeated embryonic blast cells. Previous studies have shown that homologous o blast cells give rise to an almost identical complement of descendant cells in each of the 21 abdominal segments, but that one o blast cell derivative--the distalmost cell of the nephridial tubule--is only present in 15 abdominal segments in the mature leech. Here we show that all o blast cells generate a presumptive distal tubule cell and that this cell migrates to its normal position in all abdominal segments. However, in segments which normally do not contain the mesodermal portion of the nephridium, the distal tubule cell dies before undergoing its terminal morphological differentiation. To ascertain whether the fate of the distal tubule cell is determined by its lineage history or by the segmental environment into which it is born, we utilized a previously described procedure for altering the segmental register between different embryonic cell lines. This procedure allowed us to effectively transplant o blast cells into more posterior segments prior to the cell divisions which generate their descendant clones. The results indicate that the survival or death of the distal tubule cell is determined by the identity of the host segment and that a given distal tubule cell could be effectively murdered or rescued by slipping its blast cell precursor into an appropriate segment. These findings suggest that the segment-specific pattern of distal tubule cell survival is not inherent to the O cell line, but arises from interactions with surrounding tissues.

Abdomen↗
PubMed1992

Localization of HstI transcripts to the apical ectodermal ridge in the mouse embryo.

The HstI gene is a transforming gene, coding for a protein of the fibroblast growth factor family (Sakamoto et al., 1986). Previous RNA hybridization studies with the mouse homolog demonstrated the presence of a 3.0-kb transcript in Day 11 and 14 mouse embryos. Here we detect a 3.0-kb transcript in the limb and body of the dissected Day 11 mouse embryo. PCR amplification using HstI-specific primers also showed comparable results. In order to localize the HstI transcripts during development, corresponding HstI cDNA was isolated, and an HstI-specific region was used as a probe for in situ hybridization analysis. Serial sections of embryos from Day 8 (early-somite stages) through Days 9, 10, 11, and 12 of gestation were examined. With the antisense probe, a signal was detected in the Day 11 and 12 embryo, where it was localized to the apical ectodermal ridge (AER) of the limb bud. This structure is well known for its role in promoting the distal outgrowth of the developing limb bud. Signal was detected in both fore- and hindlimbs during the period of rapid distal growth. This restricted localization suggests a role for HstI in normal embryogenesis, including outgrowth of the limb bud.

Animals↗
PubMed1995

The prothymosin alpha gene is specifically expressed in ectodermal and mesodermal regions during early postimplantation mouse embryogenesis.

Prothymosin alpha (ProT alpha) is a highly acidic nuclear protein, once believed to have an extracellular immunoregulatory role but more recently implicated in cell proliferation and/or differentiation. Several recent studies have revealed that ProT alpha mRNA is present during embryogenesis. However, these studies did not investigate the spatial distribution of ProT alpha mRNA in the embryo. Here we present a detailed study of the spatial distribution of ProT alpha mRNA during the early stages of postimplantation development (6.5-12.5 dpc) of the mouse. Three findings are of particular interest. First, ProT alpha mRNA levels increase during the early postimplantation stages (6.5-8.5 dpc) of mouse embryogenesis. Second, ProT alpha mRNA is not uniformly distributed in the mouse embryo, but is present in a spatially specific manner. Third, we have observed that the mouse ProT alpha gene is expressed almost exclusively in ectodermal and mesoderm-derived structures, and not in cells which give rise to the definitive endoderm.

Animals↗
PubMed1989

Rapp-Hodgkin syndrome: an ectodermal dysplasia involving the teeth, hair, nails, and palate. Report of a case and review of the literature.

Rapp-Hodgkin syndrome is a rare form of ectodermal dysplasia involving the hair, eyes, sweat glands, nails, teeth, and palate. The case of a white girl with the condition is presented. The differential diagnosis is discussed, and the eight previously reported cases are reviewed. Another (ninth) previously reported case is considered for inclusion in the group.

Child, Preschool↗
PubMed1993

Placement of an endosseous implant in a growing child with ectodermal dysplasia.

This article reports placement of a single mandibular endosseous implant in a 5-year-old patient with hypohidrotic ectodermal dysplasia and oligodontia. This congenital anomaly does not appear to retard healing and the osseointegration remains after 5 1/2 years of loading. Surgical, prosthodontic, and growth and development considerations are presented.

Anodontia↗
PubMed1983

Oenocyte differentiation correlated with the formation of ectodermal coating in the embryo of a cockroach.

The first signs of 'embryonic membrane' deposition could be observed at the 11th/12th stage of the embryonic development, while serosal apolysis occurs, and the first signs of oenocyte differentiation could be detected at the 15th stage. When pleuropodial cuticle deposition occurs, at the 16th stage, there is a rapid increase in the number of differentiating oenocytes. At the 19th stage there are some fully differentiated oenocytics, whereas, just before the cuticulin layer of the embryonic cuticle is laid down, another wave of oenocyte differentiation could be observed. The differentiation process of oenocytes and of vertebrate cells with a rapid cell membrane biogenesis (steroid secreting cells and hepatocytes) are compared. The correlation of oenocyte differentiation with ectodermal coating deposition, with molting hormone titer and with prothoracic gland differentiation is discussed.

Animals↗
PubMed1993

FGF-4 replaces the apical ectodermal ridge and directs outgrowth and patterning of the limb.

The apical ectodermal ridge plays a key role in limb development. We show that recombinant FGF-4 can substitute for the ridge to provide all the signals necessary for virtually complete outgrowth and patterning of the chick limb. FGF-4 stimulates proliferation of cells in the distal mesenchyme and maintains a signal from the posterior to the distal mesenchyme that appears to be required for elaboration of skeletal elements in the normal proximodistal sequence. Moreover, retinoic acid, which is capable of providing polarizing activity, can supply this signal. This suggests that polarizing activity plays a role in patterning along the proximodistal axis, in addition to its well-established role in anteroposterior patterning. Taken together, the data suggest a simple mechanism whereby FGF-4 links growth and pattern formation during limb development.

Animals↗
PubMed1994

Patterning of mammalian somites by surface ectoderm and notochord: evidence for sclerotome induction by a hedgehog homolog.

An early step in the development of vertebrae, ribs, muscle, and dermis is the differentiation of the somitic mesoderm into dermomyotome dorsally and sclerotome ventrally. To analyze this process, we have developed an in vitro assay for somitic mesoderm differentiation. We show that sclerotomal markers can be induced by a diffusible factor secreted by notochord and floor plate and that heterologous cells expressing Sonic hedgehog (shh/vhh-1) mimic this effect. In contrast, expression of dermomyotomal markers can be caused by a contact-dependent signal from surface ectoderm and a diffusible signal from dorsal neural tube. Our results extend previous studies by suggesting that dorsoventral patterning of somites involves the coordinate action of multiple dorsalizing and ventralizing signals and that a diffusible form of Shh/Vhh-1 mediates sclerotome induction.

Animals↗
PubMed1990

Ectodermal dysplasia: the otolaryngologic manifestations and management.

Ectodermal dysplasia is a rare group of diseases presenting special problems in management for the otolaryngologist, but the full spectrum of otorhinolaryngologic manifestations has been previously unrecognized in the otolaryngologic literature. The anhidrotic form, characterized by deficient sweating, sparse hair growth and deficient teeth, with associated decreased mucous production in the aerodigestive tract leads to chronic upper respiratory tract infections, otitis, dysphagia, hoarseness, bronchitis and sometimes hemoptysis.

Acute Disease↗
PubMed1992

Rapp-Hodgkin ectodermal dysplasia.

Rapp-Hodgkin syndrome is a rare condition that is characterized by ectodermal dysplasia and palatal abnormalities. We describe a 24-year-old white woman who has Rapp-Hodgkin syndrome that is associated with a chronic palmar keratoderma, which is a finding that has not been previously reported. We review the literature, assign the clinical features into major and minor categories, and suggest therapeutic interventions to limit the significant sequelae of this autosomal dominant syndrome.

Adult↗
PubMed1992

Cutaneous findings in a new syndrome of autosomal recessive ectodermal dysplasia with corkscrew hairs.

BACKGROUND: The association of hair shaft abnormalities with the phenotypic findings of a new, distinct form of an autosomal recessive syndrome of ectodermal dysplasia was present in 27 patients from seven families. OBJECTIVE: Our purpose was to present the cutaneous findings that characterize this syndrome with particular attention given to the hair shaft abnormalities. METHODS: Multiple field visits were used to gather data on phenotypic findings and prospectively evaluate their prevalence. RESULTS: Corkscrew hair, an exaggeration of pili torti, represents the most striking feature of this syndrome. Prominent cutaneous findings include scalp keloids, follicular plugging, keratosis pilaris, xerosis, eczema, palmoplantar keratodermia, cutaneous syndactyly, onychodysplasia, and conjunctival neovascularization. Other features include typical facies, anteverted pinnae, malar hypoplasia, cleft lip and palate, and dental abnormalities. CONCLUSION: A syndrome characterized by pili torti and corkscrew hairs, previously reported in only one patient, can be recognized.

Adolescent↗