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At least 775 records · Page 43Linked to original sources
PubMed1990

Identification of functioning sweat pores and visualization of skin temperature patterns in X-linked hypohidrotic ectodermal dysplasia by whole body thermography.

In this preliminary study, non-invasive infrared thermography has been used to visualize individual sweat pores and whole body skin temperature patterns in subjects with X-linked hypohidrotic ectodermal dysplasia (XHED) and normal controls. The findings in eight obligate heterozygotes and four affected males were compared to six normal female controls and to six non-manifesting females at risk for carrier status. Sweat secretion from individual pores in circumscribed areas was imaged using a high spatial resolution SPRITE infrared detector system working in the 8-14 microns band. In seven out of eight obligate heterozygotes, skin areas devoid of active sweat glands were found on the face, the hands or the trunk. Tear front movement over the cornea was also visualized and abnormal patterns were identified in obligate heterozygotes. Whole body skin temperature patterns, obtained with an Agema 780 Medical Thermovision system, identified abnormal skin temperature distributions, including characteristic aberrant "cascade" back patterns, in obligate carriers. Two out of six "at risk" females had skin temperature patterns comparable with obligate heterozygotes and we have tentatively concluded that they are carriers. Thermal imaging may be used for the examination of "at risk" non-manifesting females in families with a single affected male. The results of this study suggest that the random X-inactivation in females with XHED, as well as producing relatively large skin areas with sweat pore aplasia, is also associated with abnormal temperature patterns that are consistent with altered peripheral vascular perfusion.

Adolescent↗
PubMed1986

Close linkage between X-linked ectodermal dysplasia and a cloned DNA sequence detecting a two allele restriction fragment length polymorphism in the region Xp11-q12.

EDA (ectodermal dysplasia, anhidrotic) is an X-linked recessive disorder characterized by hypohidrosis, hypoor anodontia, and hypotrichosis. A possible linkage between the gene for EDA and a number of restriction fragment length polymorphisms (RFLPs) spread over the X chromosome was investigated in two Danish families segregating EDA. No recombination between the gene for EDA and our probe pTAK8, which detects a two allele polymorphism in the region Xp11-q12, was found in nine informative meiotic events (seven of which are phase known), giving a maximal lod score of 2.41 at a recombination fraction of 0.00. This juxtacentromeric location of the gene for EDA agrees well with the linkage data obtained with the other markers used in this study.

Adolescent↗
PubMed1987

X-linked hypohidrotic ectodermal dysplasia: DNA probe linkage analysis and gene localization.

A linkage study of 24 families with hypohidrotic (anhidrotic) ectodermal dysplasia (HED) has been performed. The previously suggested linkage to DXYS1 has been confirmed, and linkage to probes DXS14 and DXS3 has been established. We suggest that the HED locus lies in the centromeric region between DXYS1 on the long arm and DXS14 on the short arm of the X chromosome, probably on proximal Xq.

Chromosome Mapping↗
PubMed1980

Neural crest replaced by gastrula ectoderm in amphibia. Effect on neurulation, CNS, gills and limbs.

Early Axolotl gastrula ectoderm was grafted into early Triturus neural stages in place of excised neural folds at the gill and anterior trunk level. Macroscopically the young graft behaves like normal neural fold material: it follows the closing host neural plate to the dorsal midline, folds into the host's interior and, especially in the gill region, moves ventrad beneath the host's epidermis. These movements cannot be interpreted as active migration. They are the result of passive displacements by morphogenetic forces inside the embryo. Histologically the graft differentiates into neural and neural crest tissue, the quantitative relation depending on the host's region. At the gill level the graft forms mesenchyme and other neural crest elements and hardly any neural structures. In the trunk about one half of the graft forms a secondary, surplus CNS. Problems of induction, differences between gill and trunk region and between graft and normal fold behaviour are discussed. Limbs develop normally. The dorsal layer of the blastema is furnished by graft cells. Host and graft tissue can stay separate or form a combined blastema.

Ambystoma↗
PubMed1993

N-ethyl-N-nitrosourea-induced prenatally lethal mutations define at least two complementation groups within the embryonic ectoderm development (eed) locus in mouse chromosome 7.

Two loci [l(7)5Rn and l(7)6Rn] defined by N-ethyl-N-nitrosourea (ENU)-induced, prenatally lethal mutations were mapped by means of trans complementation crosses to mice carrying lethal deletions of the albino (c) locus in Chromosome (Chr) 7. Both loci were found to map to the subregion of the Mod-2-sh-1 interval that contains the eed (embryonic ectoderm development) locus, eed has been defined by the inability of embryos homozygous for certain c deletions to develop beyond the early stages of gastrulation. Evidence for at least two loci necessary for normal prenatal development, rather than one locus, that map within the eed interval came from the observation that two prenatally lethal mutations, 3354SB [l(7)5Rn3354SB] and 4234SB [l(7)6Rn4234SB], could complement each other in trans, but could not each be complemented individually by c deletions known to include the eed locus. A somewhat leaky allele of l(7)5Rn [l(7)5Rn1989SB] was also recovered, in which hemizygotes are often stillborn and homozygotes exhibit variable fitness and survival. The mapping of the loci defined by these mutations is likely to be useful for genetic, molecular, and phenotypic characterization of the eed region, and mutations at either locus (or both loci) may contribute to the eed phenotype.

Alleles↗
PubMed1994

Cation channel blocked by extracellular Ca2+ in the apical membrane of the chick embryonic ectoderm.

In the chick embryo (20 h incubation, gastrula stage), the apical membrane of the ectodermal cells shows a high density of a non-selective cation channel which is blocked by very low extracellular Ca2+ concentrations. Properties of this channel were studied at the single-channel level using the patch-clamp technique in the cell-attached mode. With 1 mmol/l Ca2+ in the pipette, only outward current was present and the channel conductance measured at +120 mV was 25.5 pS. In the absence of Ca2+, also inward current through the channel was observed. The conductances measured at -50 mV were 49.5 pS with Na+ as the charge carrier, 72.5 pS with K+, 49.1 pS with Cs+, and 18.5 pS with Li+. The conductance measured at +80 mV was around 23 pS in all four cases. The reversal potential was similar (around 25 mV) for all four ions, which indicates a poor selectivity of the channel. In the absence of Ca2+ and the presence of 1 mmol/l ethylenebis(oxonitrilo)tetraacetate (EGTA), the kinetics of the channel were characterized by bursts of the order of seconds. During a burst, the channel flickered between one open and one closed level. The open time was constant between -30 mV and -80 mV, while the closed time decreased with hyperpolarization. The open time varied according to the permeant ion (K+ < Na+ = Cs+ < Li+). Extracellular Ca2+ blocked the inward current in a voltage-dependent manner. The Kd values, 1 mumol/l at -30 mV and 3.2 mumol/l at -80 mV, indicate that Ca2+ ions exit the channel toward the intracellular side. A weak voltage dependency of the association rate constant suggests that the Ca(2+)-binding site is close to the outside mouth. Extracellular Ca2+ was much less efficient at blocking the outward current (Kd about 1 mmol/l at 80 mV). Tetracaine, but not uraniumdioxide, decreased the opening probability of the channel. The embryonic channel shows similarities with the Ca(2+)-blockable, poorly selective channel described in the epithelium of toad urinary bladder.

Animals↗
PubMed1990

Thermal exchanges during sleep in anhidrotic ectodermal dysplasia.

Anhidrotic ectodermal dysplasia is a congenital syndrome characterized by the absence of sweat glands. A sweating test was performed on such a patient and proved his inability to sweat. Thermal exchanges during night sleep were then measured in this patient and compared with data obtained from a healthy control subject. Ambient conditions were as follows: dry bulb temperature 32.2 degrees C, relative humidity 30%-40%, wind speed 0.7 m.s-1. Polysomnographic recordings showed normal sleep patterns in both subjects, but a "first night effect" in the patient. Rectal (Tre) and mean skin (Tsk) temperatures and loss of mass were monitored continuously throughout the 8-h sleep recording. Loss of mass averaged 34.1 g.h-1 in the patient vs 78.1 g.h-1 in the control subject. No relationship with sleep stages was observed in the patient, in contrast to the control subject who experienced a decrease in evaporation during rapid eye movement sleep. Body temperatures varied little in the patient, but decreased until the 6th h of sleep in the control subject. On two occasions there was a 0.3 degrees C fall in the Tre of the patient during two slow wave sleep (SWS) phases, while Tsk and loss of mass did not change. As thermolytic processes had not varied on these two occasions, it was concluded that the fall in Tre indicated a concomitant decrease in metabolic heat production, in agreement with the assumption that SWS represented a state of energy conservation.

Adolescent↗
PubMed1997

The community effect and ectoderm-mesoderm interaction in Xenopus muscle differentiation.

Community effects are believed to play an important role in the patterning of many tissues during development. They involve an interaction between neighbouring equivalent cells that is necessary for them to proceed to their fully differentiated state. However, the mechanisms underlying these effects remain unclear. In this paper, diffusion-based mathematical models are constructed and analysed in order to study possible mechanisms for the community effect in Xenopus muscle differentiation. These models differ from each other in the assumptions that are made about the nature of an inhibitory effect that ectodermal tissue has been observed to have on muscle differentiation. It is possible to construct consistent models based on all the forms of inhibition considered. However, each model requires the diffusible factors on which it is based to have different properties. The current data from tissues reaggregate experiments are insufficient to determine the mechanisms underlying the community effect; the work presented here suggests that quantitative analysis of a further series of reaggregate experiments will make it possible to distinguish between the proposed mechanisms.

Animals↗
PubMed2000

[Anesthesia in a child presenting a anhydrotic ectodermic dysplasia associated with a multiminicore myopathy].

PURPOSE: To report the perioperative management of anesthesia and analgesia in a child presenting with the association of multiminicore myopathy (MMM) and anhydrotic ectodermic dysplasia (AED). CLINICAL FEATURES: An eight-year-old girl was admitted for elective orthopedic surgery of the lower limbs. AED is a congenital dermatosis characterized by the absence of sweating and subsequent problems with thermoregulation; in addition, maxillary hypoplasia and abnormal teeth can render intubation difficult. MMM is a rare congenital myopathy characterized by proximal muscle weakness, stable in time or with a slow and progressive evolution. It can involve respiratory muscles and be associated with severe cardiomyopathy. Moreover, MMM shares some characteristics with Central Core Disease which is known to be associated with malignant hyperthermia. Since depolarizing muscle relaxants and halogenated agents could not be used, a combined propofol-based intravenous anesthesia with lumbar epidural analgesia was chosen. This combination provided stable anesthesia, smooth recovery and excellent analgesia during and after the operation, without complications. Temperature was monitored closely during surgery and in the postoperative period. CONCLUSIONS: The association of MMM and AED requires rapid distinction between hyperthermia secondary to anhydrosis and malignant hyperthermia. The management should provide a "trigger-free" anesthetic and optimal postoperative analgesia without sedation. If appropriate for the surgical procedure, a combination of general with regional anesthesia is particularly attractive in achieving these objectives.

Analgesia↗
PubMed1994

[Anhidrotic ectodermal dysplasia. Disorder of the differentiation of hair follicles and sweat glands leads to abnormal keratinization].

We report on an 11-year-old female patient with anhidrotic ectodermal dysplasia (AED) showing the following characteristics: (1) reduced number of hair follicles and incomplete formation of sweat glands; (2) disturbed hair growth with shortening of anagen and anhidrosis; (3) disturbed cytokeratin expression pattern of CK 13, 14, 19 (follicular epithelium) and of CK 18 (eccrine sweat glands); (4) reduction of cystine and increase in sulphonic cysteine acid. Thus, we demonstrated pathological differentiation on the immunomorphological and on the biochemical level, leading to disturbed keratinization that could be visualized by transmission and scanning electron microscopical studies of the hair shafts. According to these findings AED is a developmental defect that involves not only incomplete formation of hair follicles and sweat glands but also a disordered differentiation and follicular keratinization with disturbed cytokeratin pattern and pathological amino acid composition of the terminal hairs produced.

Antibodies, Monoclonal↗
PubMed2004

Gene content of the 750-kb critical region for mouse embryonic ectoderm lethal tcl-w5.

Mice homozygous for the t(w5) allele arrest at gastrulation from defects associated with embryonic ectoderm development. The mutated gene has been genetically closely linked to the H-2K locus in the mouse MHC region, flanked by markers H-2Pb and D17Mit147. Aiming at the positional cloning of the mutated gene, we constructed a BAC contig spanning about 1 Mb of the genomic region. On the basis of our mapping and sequencing analysis of the BACs combined with public genome data, EST database searches, and gene prediction programs, we delimit the 1.06 cM of the t(w5) critical region to 750 kb, and infer 36 genes (1/20 kb) encoded in the interval. All of the 33 genes tested were confirmed as expressed in embryonic tissues by RT-PCR analyses, and in many cases by EST expression profiles as well. Thus, this highly gene-rich region is essentially totally transcribed during early development and provides priority candidates to be screened for the t(w5) embryonic lesion.

Animals↗
PubMed2005

Mutation identification in a canine model of X-linked ectodermal dysplasia.

X-linked hypohidrotic ectodermal dysplasia (XHED), an inherited disease recognized in humans, mice, and cattle, is characterized by hypotrichosis, a reduced number or absence of sweat glands, and missing or malformed teeth. In a subset of affected individuals and animals, mutations in the EDA gene (formerly EDI), coding for ectodysplasin, have been found to cause this phenotype. Ectodysplasin is a homotrimeric transmembrane protein with an extracellular TNF-like domain, which has been shown to be involved in the morphogenesis of hair follicles and tooth buds during fetal development. Some human XHED patients also have concurrent immunodeficiency, due to mutations in the NF-kappaB essential modulator protein (IKBKG; formerly NEMO), which is also encoded on the X chromosome. In a breeding colony of dogs with XHED, immune system defects had been suspected because of frequent pulmonary infections and unexpected deaths resulting from pneumonia. To determine if defects in EDA or IKBKG cause XHED in the dogs, linkage analysis and sequencing experiments were performed. A polymorphic marker near the canine EDA gene showed significant linkage to XHED. The canine EDA gene was sequenced and a nucleotide substitution (G to A) in the splice acceptor site of intron 8 was detected in affected dogs. In the presence of the A residue, a cryptic acceptor site within exon 9 is used, leading to a frame shift and use of a premature stop codon that truncates the translation of both isoforms, EDA-A1 and EDA-A2, resulting in the absence of the TNF-like homology domain, the receptor-binding site of ectodysplasin.

Animals↗
PubMed2000

Expression pattern of XIRG, a marker for non-neural ectoderm.

XIRG (for Xenopus IRG) was cloned by screening a cDNA library of UV-ventralized stage 13 Xenopus laevis embryos for specifically ventrally expressed mRNAs. Embryonic XIRG mRNA expression is restricted to non-neural ectoderm at the gastrula and neurula stages. In adult X. laevis, XIRG mRNA can be detected in skin and kidney. Extensive searches in nucleic acid and protein databases revealed homologous sequences in mouse, human and zebrafish. Mouse IRG1 mRNA is expressed in cultured macrophages as a response to bacterial lipopolysaccharide treatment.

Amino Acid Sequence↗
PubMed2004

Premature regression of the leg apical ectodermal ridge in the Japanese chick wingless mutant.

The autosomal dominant Japanese wingless mutant has varying degrees of wing and leg truncations. The wing defects range from complete loss to negligible defects, whereas leg abnormalities are usually restricted to loss of the phalanges. Further analyses of the mutant focusing on the leg, which has been relatively uncharacterized, were performed. The expression pattern of Fgf8, a marker gene for the apical ectodermal ridge (AER) that controls outgrowth of the limbs, revealed premature regression at stage 28. Electron microscopy study showed abnormalities in the basement membrane all through the AER in the same stage. In the mutant, cell death was observed in the mesenchyme underlying AER between stages 31 and 32, although in the wild-type leg, AER regression and cell death occurred almost simultaneously at stages 33-34. To know if the cell death and cessation of the outgrowth are common mechanisms of wild-type and the mutant, we removed the AER in wild-type embryos at stage 28 and followed the fate of the limb. This also resulted in premature cell death 48 h after AER removal (equivalent to stage 32) and limb truncations similar to those observed in mutant limbs. To confirm whether either AER or underlying mesenchyme is responsible for the truncation, transplantation of the AER between the wild-type and the mutant was performed. This revealed that AER is the defective tissue in this mutant.

Animals↗
PubMed2004

Intrinsic cartilage-forming potential of dermomyotomal cells requires ectodermal signals for the development of the scapula blade.

The avian scapula has a dual origin. The cranial part derives from the somatopleure of the forelimb field, while the caudal part, the scapula blade, originates from the dermomyotomes of the cervicothoracic transition zone. Thus, these dermomyotomes have, in addition to the well-known myogenic, angiogenic, and dermogenic potential, the ability to form cartilage. The scapula blade is therefore a derivative of dermomyotomal chondrogenesis. Although the mechanisms that direct the sclerotomal chondrogenesis are beginning to be understood, little is known about dermomyotomal chondrogenesis. Here, we address the mechanisms that control dermomyotomal cells to become chondrocytes. After heterotopic transplantation of dorsal epithelial somite halves from the scapula-forming level to the cervical level, the grafted tissue retains the capability to form cartilage, indicating that the dermomyotomal chondrogenic potential must be specified during anterior-to-posterior regionalization of the paraxial mesoderm. Furthermore, we show that signals from the ectoderm are required, allowing dermomyotome cells to express markers associated with the chondrogenic lineage.

Animals↗
PubMed2006

A novel de novo frame-shift mutation of the EDA gene in a Chinese Han family with hypohidrotic ectodermal dysplasia.

Hypohidrotic ectodermal dysplasia (HED) is characterized by severe hypohidrosis, hypotrichosis, and hypodontia. It can be inherited in autosomal dominant, autosomal recessive, or X-linked patterns. Mutations in the EDA gene, which encodes ectodysplasin-A, are responsible for X-linked HED (XLHED). In the present study, we identified a Chinese Han family with XLHED. Direct DNA sequence analysis of the entire coding region and exon-intron boundaries of EDA identified a novel de novo mutation, c.573_574insT, in two affected males and one carrier female. Restriction fragment length polymorphism (RFLP) analysis showed that the mutation was not present in 200 controls. The 1-bp insertion mutation resulted in a frameshift, which causes premature termination of EDA polypeptide and truncation of the EDA protein. These results suggest that the c.573_574insT mutation of the EDA gene is a cause for XLHED in the family. To the best of our knowledge, this is the first de novo insertion mutation of EDA described for XLHED.

Adult↗