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In two brothers and their sister, ectodermal defects including hypodontia, onychodystrophia, trichodysplasia and palmoplantar keratosis were observed. In addition to the ectodermal dysplasia a diffuse palmoplantar eccrine hyperplasia was noted as well as tumours and cysts of eccrine origin. This seems to be the first report of familial occurrence of eccrine tumours.
Under the influence of tarsometatarsal dermis of 13-17-day chick embryos, 6.8-day amnionic ectoderm can form scales and express keratins specific for scales. In contrast, 10.5-day shank dermis can induce both feather filaments and scales in the amnionic ectoderm.
Limb buds in normally developing foetal rats and rats with the polydactyly-luxate syndrome at day 14 and 15 of intrauterine growth were studied at the optical and electron microscopic levels. Four sets of limb buds were collected and evaluated: 14th e.d.N., 14th e.d.P., 15th e.d.N., and 15th e.d.P. (e.d. embryonic day, N - normodactylous, P - polydactylous); they were studied for apical ectodermal ridge development with reference to the rates of cell death and mitosis. Both phenomena were evaluated quantitatively. A significant difference was found in the rate of physiological cell death, which was far lower in polydactylous (4.33 and 28.73) as compared with normodactylous individuals (62.40 and 82.11 cell deaths per 300 cells in the ridge on days 14 and 15). The difference found documents a considerable retardation in cell death rate in the polydactylous apical ectodermal ridge epithelium. Physiological cell death is associated with a process called apoptosis, which is characterized by the presence of "apoptotic bodies" in the cytoplasm of epithelial cells and in the intercellular space. The total number of mitoses in the ridge epithelium was relatively low (4.63 - 6.33 per 300 cells) and the differences between norm and polydactyly were not statistically significant.
X-linked hypohidrotic ectodermal dysplasia (H.E.D.) is a disorder of abnormal morphogenesis of ectodermal structures and is of unknown pathogenesis. Neither relatively accurate carrier detection nor prenatal diagnosis has been available. Previous localization of the disorder by linkage analysis utilizing restriction-fragment polymorphisms, by our group and others, has placed the disorder in the general pericentromeric region. We have extended our previous study by analyzing 36 families by means of 10 DNA probes at nine marker loci and have localized the disorder to the region Xq11-Xq21.1, probably Xq12-Xq13. Three loci--DXS159 (theta = .01, z = 14.84), PGK1 (theta = .02, z = 13.44), and DXS72 (theta = .02, z = 11.38)--show very close linkage to the disorder, while five other pericentromeric loci (DXS146, DXS14, DXYS1, DXYS2, and DXS3) display significant but looser linkage. Analysis of the linkage data yields no significant evidence for nonallelic heterogeneity for the X-linked form of the disorder. Both multipoint analysis and examination of multiply informative meioses with known phase establish that the locus for H.E.D. is flanked on one side by the proximal long arm loci DXYS1, DXYS2, and DXS3 and on the other side by the short arm loci DXS146 and DXS14. Multipoint mapping could not resolve the order of H.E.D. and the three tightly linked loci. This order can be inferred from published data on physical mapping of marker loci in the pericentromeric region, which have utilized somatic cell hybrid lines established from a female with severe manifestations of H.E.D., and an X/9 translocation (breakpoint Xq13.1). If one assumes that the breakpoint of the translocation is within the locus for H.E.D. and that there has not been a rearrangement in the hybrid line, then DXS159 would be proximal to the disorder and PGK1 and DXS72 would be distal to the disorder. Both accurate carrier detection and prenatal diagnosis are now feasible in a majority of families at risk for the disorder.
Two growth hormone-deficient patients with particular developmental defects are presented. One patient had the ectrodactyly-ectodermal dysplasia-clefting syndrome with lobster-claw deformities of the hands; thin, blond, and dry hair and enamel hypoplasia; and a facial raphe on the right side of the philtrum. The other patient had isolated absence of the septum pellucidum. The facial raphe and the absent septum pellucidum are related to cleft lip and septooptic dysplasia, conditions that have been associated with growth hormone failure. The association of the ectrodactyly-ectodermal dysplasia-clefting syndrome with isolated growth hormone deficiency has not been described previously.
The inducing influence of adult eye tissues on the early gastrula ectoderm was studied in vitro. Both retina and pigment epithelium induced in the early gastrula ectoderm similar spectra of cell types, including nervous tissue, retina, pigment epithelium, lentoids, ectomesenchyme, and melanophores. It is suggested that the correspondence of these cell types with those arising at a spontaneous transdifferentiation of the isolated retina and pigment epithelium cells in vitro or at the induction of the early gastrula ectoderma by archencephalic endomesoderm during the normal development can be accounted for by that in these eye cells molecular determinants appeared as a result of induction and maintaina the stability of their differentiation and their potencies to transdifferentiation in vitro being reproduced during the lifetime of these cells.
The effects of procaine and pentobarbital on lens placodes, otic placodes and non-placodal head ectoderm of the chick embryo in vitro have been examined by scanning and transmission electron microscopy. Both types of placode cells were less sensitive to both drugs than non-placodal cells. Cellular responses to pentobarbital were microvilli formation, reduction in cetylpyridinium chloride-stainable surface coat and epithelial dissociation with thinning of the basement membrane. Procaine treatment induced the formation of large cytoplasmic blebs and cytoskeletal condensations but did not affect the surface coat. Examination of head ectoderm appears to be of value in the evaluation and comparison of drug effects on differentiating tissues. Anaesthetics also form useful probes for structural and functional changes in the cells of such developing systems.
1. Optic cups of 48, 72 and 96 hours old chick embryos were prepared, cultured and recombined with ectoderm. With the optic cups of 48 hours old embryos, lens formation occurred in 16% of the cases. With the optic cups of 72 hours old embryos, lens formation occurred in 28% of the cases. Optic cups of 96 hours old embryos were not able to induce a lens. 2. The optic cup proved to be able to induce a lens more than once. 3. Ectoderm of the head of 72 hours old embryos was still able to form a lens. 4. Using homogenized eye cups of 72 hours old embryos, lens induction occurred only in a few cases. When the optic cups were cut into small pieces, lens induction occurred in 30% of the cases. This suggests that intact cells are necessary to obtain lens induction.
20 water-soluble antigen have been identified with the help of rabbit antisera to extracts of the early gastrula ectoderm and neural plate in Rana temporaria. All of them were also found in the early blastula embryos and unfertilized eggs. The identified antigens are characterized by a definite embryospecificity. As the development proceeds, the concentration of these antigens in the embryonic tissues decreases until the complete disappearance of corresponding immunoelectrophoretic reactions. By this characteristic all antigens under study are subdivided into four groups: I--five antigens identified at the early developmental stages only (until hatching, stage 29); II--nine antigens present up to stages 33--35; III--three antigens followed up to stages 39--40 (well formed tadpole); IV--three antigens were found at all developmental stages under study up to stages 45--47. 11 out of 20 identified antigens have antigenic similarity with the proteins of blood serum of adult amphibians. Besides, the early gastrula ectoderm contains antigens similar with those of the brain of adult amphibians.
The water extracts from the retina and brain of 7-8-day old chick embryos were centrifuged at 20,000 g; sediments were discarded and supernatants were additionally centrifuged at 110,000 g. The inductive activity of supernatants (20,000 and 110,000 g) and sediments (110,000 g) was estimated in vitro on the Rana temporaria early gastrula ectoderm. The neutralizing activity was related exclusively to the soluble fractions of the extracts from the chick embryo retina and brain. The lens-inducing activity appeared to be characteristic of both the supernatants and the microsome fractions of these extracts. A comparative biochemical analysis of the extracts (isoelectrofocusing, electrophoresis in the presence of sodium dodecylsulfate, electroblotting) has shown that the chick embryo retina and brain are similar by the spectrum and properties of peptides. It is suggested that the similarity of the extracts inducing effect on the early gastrula ectoderm is due to the presence of the same proteins (peptides) in the retina and brain. Peptides with a positive immunohistochemical reaction to vimentin and peptides of neurofilaments were found in trace quantities in the retina and brain extracts by means of immunoelectroblotting.
By combining transmission electron microscopy (TEM), scanning electron microscopy (SEM) and immunocytochemistry at both light and TEM levels the organization of actin in early chick ectoderm has been demonstrated. Every cell is encircled by a ring of actin filaments which are associated with apically situated intercellular junctions. In this way the actin ring of each individual cell is connected to that of surrounding cells and a continuous network is formed. As clearly shown by immunofluorescence and SEM studies on intact and Triton X-100 treated whole-mount preparations this network extends throughout the entire layer, interrupted only at the blastoderm margins and the primitive streak. A more diffuse arrangement was sometimes seen at cell bases. It is suggested that the network extending throughout the ectoderm gives it stability and cohesion and is important in gross morphogenetic movements involving the entire layer. The less-organized arrangement at cell bases is associated more with movements of individual cells.
Cells of the superficial layer which had been explanted from the presumptive ectoderm of Rana japonica early gastrulae at stage 10 differentiated into cement-gland cells (CGCs) when cultured in Barth's solution containing 90-130 mM-NaCl, and into common epidermal cells and cilia cells when cultured in a solution containing 20-40 mM-NaCl. They failed to differentiate, however, when cultured in a solution in which NaCl is 15 mM or lower. The optimum condition for inducing the differentiation of CGC was stimulating them with a solution containing 130 mM-NaCl for 6-10 h at 18 degrees C, followed by culturing in a solution containing 15-40 mM-NaCl for 7 days. The greatest ability to react to the CGC-inducing stimuli resided in the superficial layer of the presumptive ectoderm of the embryo at stages 10-11. Under the optimum condition, the total volume of CGCs induced amounted to about 85% of the explanted tissue. High percentage comparable to this was obtained with stimulation by KCl, RbCl, sucrose or mannitol.
The primary symptom in the tooth system, a tendency toward aplasia of the bicuspid teeth in both dentition periods, was reported for an ectodermal syndrome which has seldom been described. In agreement with the observation by BOOK (1950), we also observed excessive perspiration (hyperhidrosis) and premature graying of the scalp hair (canities prematura). The syndrome, which is limited to ectodermal disturbances, is a dominant trait, the incidence of which is apparently higher in Northern European countries. Trigeminal neuralgias seem to appear in conjunction with this genetic disturbance. Compared with other partial anodontic and oligodontic syndromes, it is striking that no other groups of teeth are affected; the bicuspid teeth however show signs of aplasia, hypoplasia, structural disturbances (discoloration), and premature loss of even the deciduous teeth.
In 2 patients with anhidrotic ectodermal dysplasia, we were able to show that the hypoplastic eccrine glandular elements may give rise to normal eccrine glands both anatomically and functionally, after repeated local application of acetylcholine. The perspectives of our findings for the therapeutic management of the anhidrotic ectodermal dysplasia are discussed and special attention is paid to the genetic background of the defect as well as the possible mode of action of acetylcholine.
A case is presented of anhidrotic ectodermal dysplasia, of extreme rarity. This is distinguished by disorders in the structures of ectodermal origin. The clinical characteristics--hypohidrosis, hypodontia, hypotrichosis-, and the genetic features--genealogy, karyotype--are examined first. The patient's face appears to be small, due to the combination of frontal bossing, hypodontia, and a depressed nasal dorsum, somewhat resembling the saddle nose of congenital syphilis. The case is studied from various perspectives: clinical, radiological, anatomicopathological and ultrastructural. The study concentrates principally on the anomalies of the nasal cavities, where there is a notable atrophy of the nasal mucosa. This atrophic rhinitis displays all the features of ozaena: severe crusting, fetid green secretion, nasal obstruction, etc.
HLA-ABC antigen typing was carried out in 4 homozygous patients and 10 family members from three families with bullous epidermolysis, 7 homozygous patients and 19 family members of six families with ichthyosis, and 4 homozygous patients and 8 family members of 4 families with ectodermal dysplasia. The type of heredity was established on the basis of genetical evidence and the clinical picture. In bullous epidermolysis cases autosomal recessive heredity was detected in two families with congenital bullous epidermolysis, and autosomal heredity in two families with dystrophic bullous epidermolysis. The HLA-Aw 24, B5 combination, which was thought to be significant in epidermolysis bullosa, was found in one, B5 alone in two, out of the four families. In congenital ichthyosis autosomal recessive heredity was detected in two families out of five. In one, X-linked recessive heredity was found, and in two families X-linked recessive heredity could be supposed. In three families out of the five with congenital ichthyosis, the A2, B18 antigen combination was found. In a family where two infants died from the most severe form of ichthyosis, epidermolysis and psoriasis also occurred. In this family two grandfathers were brothers, and one of the two was a carrier of the Aw24, B5 combination. In the case of ectodermal dysplasia, in one out of four families X-linked recessive heredity, in another autosomal recessive heredity was detected. In two families X-linked recessive heredity could be supposed as only the male children were affected and also on the basis of data in the literature. The HLA-A26, B38 antigen combination occurred in three of these four families.
The potency of 8th day mouse embryonic ectoderm cells has been studied by injecting them into synchronous embryos which were subsequently cultured for 36 h. The development of injected embryos in vitro was comparable to that of embryos maintained in vivo. Tritiated thymidine was used to label the donor cells so that chimaerism could be analysed histologically. The results demonstrate the pluripotency of embryonic ectoderm in situ in the late primitive-streak-stage embryo. In addition, the patterns of donor cell colonization vary according to the site of origin and injection of the donor tissue.
The dependence of the differentiation-pattern of competent amphibian ectoderm on the proportion of inducing and induced material was studied. To do so different masses of LiCl-treated tissue were combined with a constant mass of untreated material. LiCl-treated isolates corresponding in size with the treated portions in the combinations served as controls. The experiments seem to show at least three factors responsible for the differentiation-pattern of the combinations: the number of inducing cells, the number of cells to be induced, and the competence of the ectoderm, which depends on the stage of development.