Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    British journal of dermatology 104 (1981), S. 0 
    ISSN: 1365-2133
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Upper limb buds of mouse embryos (day 11 + 3 h of development) were cultured for 6 days. During this time the epidermis develops from a two-layered stage, consisting of a basal cell layer and a periderm cell layer, to a multilayered squamous epithelium with a stratum granulosum and a stratum corneum. To investigate the cell kinetics of epidermis and periderm during epidermogenesis the limb buds were labelled with 3H-thymidine at different stages of development. The migration of labelled cells was studied on day 3 in vitro. In the first period of development, before a stratum granulosum has differentiated, each individual cell layer of the epidermis has a cell cycle of its own, i.e. once it has developed each cell layer grows independent of the other. The switching from horizontal to vertical proliferation starts on day 4 of culture with the appearance of the stratum granulosum and is completed on day 5 when a corneal layer begins to develop. With the appearance of the stratum corneum the limb bud shows the typical proliferation of the adult epidermis, which is regenerating only from the basal layer.The labelling behaviour of periderm cells also shows that these cells have a cell cycle of their own and are not formed by cells migrating from the epidermis in an upward direction.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 188 (1993), S. 579-585 
    ISSN: 1432-0568
    Keywords: Human embryo ; Paraxial mesenchyme ; Sclerotome ; Lectins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The paraxial mesenchyme in seven human embryos aged between Carnegie stages 12 and 17 was studied by lectin histochemistry with the lectins AIA, Con A, GSA II, LFA, LTA, PNA, RCA I, SBA, SNA, WGA. The paraxial mesenchyme was found to be segmented into sclerotomes by intersegmental vessels and from late stage 12 by intrasclerotomal clefts dividing each sclerotome into a cranial and caudal half. The lectins Con A, GSA II, LFA, LTA, SBA and SNA did not react at all in the paraxial mesenchyme. Staining for AIA, PNA, RCA I and WGA was found in the developing sclerotomes. However, no differences in the staining pattern between the two sclerotomal halves could be seen. It was striking that in contrast to the chick embryo no differences in binding for PNA between the cranial and caudal sclerotomal parts was observed. These findings reveal that PNA-binding sites do not play the same functional role in segmented axonal outgrowth and neural crest immigration into cranial sclerotomal halves in the human embryo, as found in chick embryonic development. Beginning with the stage 16-embryo, the already condensed caudal sclerotomal halves express Con A-, RCA- and PNA-binding sites. The staining for PNA in particular marked the differentiation of chondrogenous structures developing in this half. From the late stage 12 or stage 13, the walls of intersegmental and other vessels showed binding sites for AIA, PNA, RCA I, SNA and WGA.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 1432-0568
    Keywords: Mouse embryo day 6 and 7 ; Direct immunogold histochemistry ; Laminin subunits of A- and B1-chains ; Mesoderm formation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Using ultrastructural immunogold histochemistry on LR-Gold-embedded 6- and 7-day-old mouse embryos we investigated the appearance of the A- and B1-chains of the laminin molecule during mesoderm formation. With the help of antibodies against the A-chain and the E4 fragment of the B1-chain of the laminin molecule we were able to detect the subunits in vivo. Staining for the E4 fragment of the short arm of the laminin molecule from day 6 was negative. In contrast, strong staining for the A-chain of laminin was observed. Our results show, that the A-chain of laminin appears before the B1-chain in the 6-day-old mouse embryo before a basement membrane is seen between the ectodermal and entodermal cell layers. Furthermore, the staining pattern indicates, that the laminin molecule changes its orientation in the basement membrane of the ectoderm during mesoderm formation. On day 7 staining for the A-chain of laminin and for the E4 fragment was seen in a random distribution throughout the entire basement membrane, whereas in areas were the onset of mesoderm formation was taking place, the E4 fragment was restricted to the edge of the disintegrating basement membrane.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 184 (1991), S. 345-353 
    ISSN: 1432-0568
    Keywords: Human embryo ; Lectins ; Spine ; Vertebral development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Paraffin sections from vertebral columns of ten human embryos and fetuses ranging from stage 16 to the 12th week were stained with the FITC-coupled lectins PNA, RCA I, Con A and WGA in order to investigate changes in carbohydrate-binding sites during vertebral development. PNA revealed a specific binding site in the vertebral body blastema in the precartilaginous stage of development. Beginning with the 25-mm CRL embryo, PNA-binding sites occurred in the developing fibrous annulus and the inner zone of the intervertebral discs. The first binding sites for RCA I were seen in the extracellular matrix of vertebral bodies during the cartilaginous stage of vertebral development. During early ossification of the vertebrae, staining for RCA I-binding sites in the cytoplasm of the chondrocytes and the area around the future cartilaginous end-plates was observed. Con A bound to the chondrocyte cytoplasm, and also very strongly to notochordal cells in all developmental stages examined. WGA-binding sites appeared simultaneously with cartilage formation. Connective tissue components, e.g. ligaments, were diffusely stained by WGA. Also this lectin showed an affinity for vertebral body chondrocytes. We discuss the biochemical aspects of these lectin-binding sites, and their possible roles in the differentiation process of the human vertebral column. The results of this first lectin histochemical study on human vertebral development are compared with related results in other species.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 193 (1996), S. 43-51 
    ISSN: 1432-0568
    Keywords: Type II collagen ; Human embryo ; Non-radioactive in situ hybridization ; Vertebral column ; Cartilage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The role of extracellular matrix molecules in ontogenetic differentiation processes is a matter of increasing interest. In cartilage development, type II collagen is suspected of promoting chondrogenic differentiation, since its expression has been demonstrated in a range of precartilaginous tissues of vertebrate species. Up to now, no studies supplying a coherent description of type II collagen expression in the skeletogenesis of human embryos including early embryonic stages have been published. In this work, we examine the temporal and spatial distribution of type II collagen mRNA during vertebral column development in human embryos from 4 to 12 weeks of gestation using non-radioactive in situ hybridization. The onset of gene expression was demonstrable in the 5th week in precartilaginous mesenchymal cells and in notochordal cells. Additionally, we found a weaker hybridization signal in the mesenchymal precursors of the intervertbral discs. In the anlagen of the axial skeleton, type II collagen expression decreased during osteogenic reconstruction in the 11th/12th week, whereas expression continued in the notochordal remnants of the future nuclei pulposi. The results suggest a relatively late occurrence of type II collagen in human vertebral development compared with other vertebrate species. The distribution of gene expression is concordant with a possible role of this molecule in promoting differentiation of mesenchymal cells into chondrocytes. The mechanism of this influence remains to be established.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 6
    ISSN: 1420-9071
    Keywords: Key words. Heart development; extracellular matrix; heart valves; hyaluronan; immunogold staining; microfibrils.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. The microfibrillar proteins fibulin-1 and fibulin-2 were previously identified as prominent components of the endocardial cushion tissue (ECT) during heart development and shown to persist in adult valves and septa. Immunogold staining has now been used to compare their localization in embryonic (days 9–11) and adult mouse heart with that of fibronectin and the chondroitin sulphate proteoglycan versican. All four proteins were deposited in the ECT, which consists of a hyaluronan-rich, mainly unstructured matrix, but were barely detectable in myocardial basement membranes or within endocardial cells. Digestion with hyaluronate lyase selectively released the fibulins and versican but not fibronectin from the ECT. Yet neither of the two fibulins bound to hyluronan in solid-phase assays, in contrast to versican. In the adult heart valve, all four proteins could be detected close to cross-striated collagen fibrils or microfibrils, but only versican was lost upon exposure to hyaluronate lyase. The data indicate that fibulins are associated with the hyaluronan-matrix of ECT through a bridge of versican, but that this association changes upon valve development to another supramolecular, presumably microfibrillar organization based on fibronectin and/or fibrillins.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Surgical and radiologic anatomy 15 (1993), S. 131-137 
    ISSN: 1279-8517
    Keywords: Sacroiliac joint ; Computed tomography ; Secondary ossification centres ; Os sacrum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé Des formations osseuses apparemment bilatérales, de formes et tailles différentes, localisées dans les parties antéro-supérieures et inférieures des articulations sacroiliaques, ont été observées sur les images de coupes axiales de la région pelvienne chez des patients jeunes. Aucune autre modification pathologique n'a été notée au niveau des articulations sacro-iliaques de ces individus. Chez l'un des patients, les structures osseuses pouvaient aussi être observées sur les radiographies standard. Nous avons aussi étudié cette articulation chez 3 sujets anatomiques juvéniles, par la radiographie, la TDM, l'étude macroscopique et histologique. Chez deux d'entre eux des formations osseuses semblables à celles observées chez les patients jeunes pouvaient être détectées sur les coupes TDM. Les recherches macroscopiques ont montré que ces structures étaient des points d'ossification secondaires localisés dans le cartilage articulaire de la partie latérale du sacrum en regard du 1er et du 3e segments sacrés. Si l'on se réfère à une littérature anatomique plus ancienne, ces points d'ossification épiphysaires contribuent à la surface auriculaire de la partie latérale du sacrum et à la surface libre latérale des parties caudales du sacrum. Ils peuvent être observés entre 12 et 25 ans et commencent à fusionner avec les parties latérales aux environs de la 18e année. Sur les bassins osseux provenant de pièces juvéniles conservées, les ossicules libres n'ont pas pu être décelés dans la région des articulations sacroiliaques. Les particularités histologiques du processus d'ossification observé sont discutés. Ces points d'ossification physiologiques doivent être distingués des altérations pathologiques apparaissant au scanner comme des structures osseuses ou assimilées.
    Notes: Summary Bilateral apparently bony structures of different forms and sizes located in the inferior and superior ventral parts of the sacroiliac joints were observed on axial CT images of the pelvic region of juvenile patients. No other pathological changes were noted in the sacroiliac joints of these individuals. In one patient the bony structures could also be seen on a conventional plain radiograph. We also examined 3 juvenile autopsy specimens of this joint using radiology, CT, macroscopical evaluation and histology. In two of them, structures could be detected on the CT scans which were similar to those observed in the young patients. Macroscopic investigations revealed the structures to be secondary ossification centres located in the articular cartilage of the lateral part of the os sacrum at the levels of the first and third sacral segments. According to older anatomical literature, these epiphysial ossification centres contribute to the auricular surface of the lateral part of the os sacrum and the free lateral surface of the inferior sacral parts. They can be observed between the ages of 12 and 25 years and begin to synostose with the lateral part around the age of 18 years. In macerated juvenile specimens of the bony pelvis, free ossicles were not detectable in the region of the sacroiliac joints. Histological peculiarities of the ossification process observed are discussed. These physiologically occurring ossification centres are to be differentiated from pathological alterations appearing as bony or bone-like structures on CT scans.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Histochemistry and cell biology 112 (1999), S. 277-282 
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Matrix metalloproteinases (MMPs) regulate matrix deposition in tissues. Collagens I, III, and IV are involved in early human liver development. To establish whether MMPs specific for these collagens participate in early human liver development, we localized immunohistochemically MMP-1 and MMP-13 (for collagens I and III) and MMP-2 and MMP-7 (for collagen IV) in the early human liver anlage [6th–10th gestational week (GW)]. MMP-1 was found from the 6th GW onward in hepatocytes and later also in outer limiting plate hepatocytes, early bile ducts, and periportal mesenchymal cells. In the 6th GW, MMP-2 was found only in microvascular endothelium. In the 7th GW, MMP-2 was also detected in hepatocytes. From the 9th GW onward, MMP-2 was detectable in all hepatocytes and erythropoietic, endothelial, and periportal mesenchymal cells. MMP-7 was present in the 6th GW in some hepatocytes and endothelial cells, but from the 7th GW onward, only in hematopoietic cells. MMP-13 was found exclusively in hematopoietic cells. This study has shown that production of MMP -1, MMP-2, MMP-7, and MMP-13 during human liver development already occurs from the 6th GW. At this time-point their substrates are only traces or are not yet present in the tissue. A possible role of MMPs in early liver development is discussed.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    Springer
    Histochemistry and cell biology 94 (1990), S. 525-530 
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the present investigation we localized binding sites for the lectins WGA (wheat germ agglutinin), RCA I (Ricinus communis agglutinin), LFA (Limax flavus agglutinin) and SBA (soya bean agglutinin) in the 7-day-old mouse embryo at the ultrastructural level. Lectin binding sites were localized on formaldehyde fixed embryos, embedded in LR-Gold, using gold-labelled lectins. Binding sites for WGA and RCA I were observed at the surface of the embryonic ectoderm oriented towards the proamnion cavity and the outer surface of the extraembryonic and the embryonic endoderm. Staining for SBA and LFA binding sites was seen in the basement membrane of the ectoderm. Moreover, binding sites for LFA were observed in the nucleoli of cells of the ectodermal, the mesodermal and the endodermal layer and in free ribosomes located in the cytoplasm of these cells.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 10
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the present work we compared the appearance of carbohydrate binding sites for mannose, maltose, sialic acid andN-acetyl-glucosamine in the 11 to 13-day-old mouse embryo with the appearance of BSA and lectin binding sites. The carbohydrate-binding sites were localized with FITC-coupled neoglycoproteins, synthesized by chemical glycosylation of bovine serum albumin (BSA). These localizations were compared with binding of the FITC-labelled unglycosylated BSA. Furthermore the localizations of neoglycoprotein and BSA binding sites were correlated with binding of the FITC-labelled lectins WGA, RCA I and Con A. Initial appearance of neoglycoprotein binding sites occurred in the lens capsule of the 13 day old mouse embryo. Binding sites for the unglycosylated BSA appeared earlier, i.e. already in the 12-day-old embryo, in the basement membranes of the choroid plexus and the lung bud and lectin binding sites were seen in these structures in the 11-day-old embryo. The staining of the basement membrane and the lens capsule for BSA binding sites in the 12-and 13-day-old embryos correspond to WGA binding to these membranes. From these results we concluded that 1) specific carbohydrates which are probably involved in embryonic development appear much earlier in the embryo than the endogenous lectins which are able to react with these carbohydrates and 2) BSA is a protein which like WGA probably binds N-acetylglucosamine or sialic acid moieties.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...