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Results 401 - 450 of 1017
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Kobayashi C - - 1999
To understand the cellular events during planarian regeneration, we analyzed the process of pharynx regeneration in both head and tail pieces using cell-type-specific markers. Interestingly, cells expressing the pharynx-muscle-specific myosin heavy chain gene (DjMHC-A) appeared within 24 h after amputation (prior to the formation of a pharynx rudiment) in the ...
Goto A - - 1999
Annelids are strongly segmented animals that display a high degree of metamerism in their body plan. The embryonic origin of metameric segmentation was examined in an oligochaete annelid Tubifex using lineage tracers. Segmental organization arises sequentially in the anterior-to-posterior direction along the longitudinal axis of the mesodermal germ band, a ...
Keyes W M - - 1999
The incidence of apoptotic cells in the hearts of chick embryos between days 4 and 8 of development was examined using an in situ technique for the detection of DNA fragmentation. Using this method it was possible to demonstrate foci of apoptotic cells primarily in two locations: the outflow tract ...
Bollag R J - - 1999
Monitoring the migrations of cells during embryonic development requires a system in which cells can be identified in situ during locomotion. One promising system involves the generation of chimeras by transplanting mouse cells into chick embryos in ovo to exploit the wealth of mouse genetic variants. The success of this ...
Macias D - - 1999
Embryonic limb outgrowth is accomplished by the proliferation of mesodermal cells in the progress zone. In this region, mesodermal cells are maintained in an undifferentiated and proliferating state by the action of the apical ectodermal ridge (AER). Differentiation of these cells into individual skeletal elements occurs when the cells are ...
Shiga T - - 1999
The relationship between the appearance of Islet-1-expressing cells and the longitudinal growth of primary afferent axons (PAAs) in the dorsal spinal cord of chick embryos was examined. Islet-1-expressing cells first appeared in the dorsal spinal cord at embryonic days (E) 3-3.5. These immunoreactive cells were aligned in a longitudinal column ...
Koibuchi N - - 1999
During vertebrate limb development, the limb bud grows along the proximo-distal (P-D) direction, with the cells changing their adhesiveness. To know whether the position-related differences in cell adhesiveness are actually utilized by morphogenesis to constitute limb structures, we grafted cell aggregates made of dissociated cells derived from different positions and ...
Choy M - - 1999
Abnormalities of the cushion tissues lead to atrioventricular septal defects (AVSD) and truncus arteriosus (TA). Bisdiamine exposure in the embryo frequently causes AVSD and TA in the newborn chick, mouse, or rat. We studied the effects of bisdiamine on mesenchymal cells grown in aggregate culture isolated from the developing atrioventricular ...
Warga R M - - 1999
The segregation of cells into germ layers is one of the earliest events in the establishment of cell fate in the embryo. In the zebrafish, endoderm and mesoderm are derived from cells that involute into an internal layer, the hypoblast, whereas ectoderm is derived from cells that remain in the ...
Satoh F - - 1999
A case of multiple myeloma, who died of congestive heart failure of unknown cause, is presented. Microscopically, Anitschkow cells with caterpillar and owl-eyed nuclei were scattered in the interstitium of the myocardium. To know the pathological significance of their appearance, histological observations of normal, developing and autoimmune disease-bearing heart specimens ...
Dale K - - 1999
Ventral midline cells in the neural tube have distinct properties at different rostrocaudal levels, apparently in response to differential signalling by axial mesoderm. Floor plate cells are induced by sonic hedgehog (SHH) secreted from the notochord whereas ventral midline cells of the rostral diencephalon (RDVM cells) appear to be induced ...
Luchman H A - - 1999
The er1 gene is a novel fibroblast growth factor (FGF)-regulated immediate-early gene, first isolated from Xenopus blastulae, that encodes a nuclear protein with potent transcription transactivational activity (Paterno et al., 1997). We report here the expression pattern of the ER1 protein during Xenopus embryonic development. ER1 protein is present in ...
Breen J G - - 1999
Epidemiologic studies strongly suggest that in utero exposure to hyperthermia results in developmental defects in humans. Rats, mice, guinea pigs, and other species exposed to hyperthermia also exhibit a variety of developmental defects. Studies in our laboratory have focused on exposure to hyperthermia on Gestation Day (GD) 10 of rats ...
Kawasaki Y - - 1999
The effect of nitric oxide (NO) on the contractile tone of Müller cells was investigated. Müller cells, isolated from the retina of chick embryos, were cultured on thin sheets of silicone. S-Nitro-N-acetyl-DL-penicillamine (SNAP), an NO donor, was applied in the presence or the absence of carboxyl phenyltetramethylimidazole oxide (C-PTIO), an ...
Warga R M - - 1998
The dorsal marginal zone of the zebrafish blastula, equivalent to the amphibian Spemann organizer, is destined to become the tissues of the notochord and prechordal plate. Preceding gastrulation in the zebrafish, we find that these future mesendodermal cells acquire a cohesive cell behavior characterized by flattening and maximization of intercellular ...
Kahane N - - 1998
We have shown that a subset of early postmitotic progenitors that originates along the medial part of the epithelial somite gives rise to the primary myotome (Kahane, N., Cinnamon, Y. and Kalcheim, C. (1998). Mech. Dev. 74, 59-73). Because of its postmitotic nature, further myotome expansion must be achieved by ...
Bannerman P G - - 1998
The existence of phenotypic differences within a population of cells provides evidence for discrete stages in cellular differentiation and/or identifies subsets of cells with unique functional properties. The monoclonal antibody HNK-1 has been widely shown to identify subpopulations of cells in the developing nervous system. In this paper we focus ...
Wada N - - 1998
Although regional differences in mesenchymal cell affinity in the limb bud represent positional identity, the molecular basis for cell affinity is poorly understood. We found that treatment of the cell surface with bacterial phosphatidylinositol-specific phospholipase C (PI-PLC) could change cell affinity in culture. When PI-PLC was added to the culture ...
Kosher R A - - 1998
Syndecan-3 is a member of a family of heparan sulfate proteoglycans that function as extracellular matrix receptors and as co-receptors for growth factors and signalling molecules. A variety of studies indicate that syndecan-3 is involved in several aspects of limb morphogenesis and skeletal development. Syndecan-3 participates in limb outgrowth and ...
Wezeman F H - - 1998
Hyaline cartilage is archetypic for the appendicular skeleton and the vertebral column. It arises from pluirpotential mesenchymal ancestor cells that remain morphologically undifferentiated prior to a localized cell aggregation in specific regions destined to undergo chondrogenesis. The critical ultrastructural studies of limb bud mesenchymal differentiation prior to, during, and after ...
Jüngel-Waas K - - 1998
The question of regeneration after experimental somite extirpation has been controversial in the literature. While all workers agree that repair of the defects occurs, results concerning the extent and mechanism of this process, as well as the origin of the cells filling the defect, show great discrepancies. Our approach towards ...
Macías D - - 1998
Cardiac morphogenesis involves substantial remodeling processes that include cell transdifferentiation and migration. The c-ets-1 protooncogene codes for a transcription factor that can transactivate a number of genes involved in developmental processes such as degradation of extracellular matrices and cell migration. We have immunolocated the ets-1 protein in the heart of ...
Forsberg H - - 1998
During somitogenesis, cells are recruited to the caudal presomitic mesoderm (PSM) from the primitive streak (and later the tail bud), while somites separate from the rostral end as epithelial cubes. This is a regular process, one somite forming every 2 hours in the mouse, that can be simulated by clock ...
Pérez-Pomares J M - - 1998
The earliest evidence of the development of the cardiac vessels in mammals is the emergence of subepicardial blood islands, which are thought to originate from mesenchymal progenitors. In order to identify these progenitor cells, we have studied the immunohistochemical localization in the heart of Syrian hamster embryos of the type ...
Sato-Maeda M - - 1998
In chick limb buds, mesenchymal cells of the progress zone (PZ-cells) at different developmental stages segregate one from the other in mixed cell cultures, suggesting they have different cell affinity. In order to learn the possible roles of such differences in the cells, two heterotypic leg PZ-cell populations (cells from ...
Pérez-Pomares J M - - 1998
It has been proposed that the subepicardial mesenchymal cells (SEMC) originate from the primitive epicardium and also from migration of extracardiac mesenchyme from the liver area. We have studied the possibility of an origin of SEMC through transformation of the proepicardial mesothelium, as well as the potential of the early ...
Wang K C - - 1998
For the cytokinetic studies using spinal cords of chick embryos, chronological patterns of cell proliferation and programmed cell death (apoptosis) should be known. Information in the early stages of chick embryos is available while data on later stages are seldom available. To investigate the chronological patterns of cell proliferation and ...
Ide H - - 1998
A fundamental process in limb bud development is the formation of position-dependent cartilage pattern. Cells of the distal mesenchyme maintain positional values as the expression pattern of transcription factors, for example, hox genes, which induce position-related cell differentiation and cell surface differences. Cultured, dissociated limb bud mesenchymal cells segregate from ...
Dockter J L - - 1998
When the somite first forms the cells appear to be equivalent in potential. In order to understand the lineage diversification of the somite, the determination of sclerotome cells to the cartilage fate was tested using an in vivo challenge assay in which quail sclerotome fragments were grafted into a dorsal ...
Kahane N - - 1998
The ontogeny of the myotome was investigated using [3H]thymidine or Brdu treatment in conjunction with 1,1', di-octadecyl-3, 3, 3', 3',-tetramethylindo-carbocyanine perchlorate (DiI) labeling and expression of specific markers. We have identified a subset of early post-mitotic cells that is present in the dorsomedial aspect of epithelial somites and is homogeneously ...
Park I S - - 1998
In an attempt to understand cell kinetics of open neural tube defects (ONTDs) in the embryonic stages, chronological changes of cell proliferation and cell death patterns in the surgically induced spinal ONTDs of chick embryos were investigated using proliferating cell nuclear antigen (PCNA) staining and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate ...
Sherman L - - 1998
Signals from the apical ectodermal ridge (AER) of the developing vertebrate limb, including fibroblast growth factor-8 (FGF-8), can maintain limb mesenchymal cells in a proliferative state. We report here that a specific CD44 splice variant is crucial for the proliferation of these mesenchymal cells. Epitopes carried by this variant colocalize ...
van Gestel W J - - 1998
This paper describes an ultrastructural study of the cell movements during the gastrulation of the common carp, Cyprinus carpio, using scanning electron microscopy. The morphology of the deep cells was studied in several consecutive stages ranging from 0-100% epiboly. Furthermore, the formation of the embryonic shield was followed from its ...
Grupp C - - 1998
To further characterize cells of the lower portion of the thin limb of Henle (TLH1p) under defined conditions in vitro, we developed a technique to enrich this cell population in suspension. TLH1p cells were isolated by enzymatic digestion of rat inner medulla, elimination of collecting ducts by lectin-coated beads, and ...
Waldrip W R - - 1998
Smad proteins transmit TGFbeta signals from the cell surface to the nucleus. Here we analyze Smad2 mutant embryos created using ES cell technology. Smad2 function is not required for mesoderm production per se, but, rather unexpectedly, in the absence of Smad2 the entire epiblast adopts a mesodermal fate giving rise ...
Moore L A - - 1998
During gastrulation, the Drosophila mesoderm invaginates and forms a single cell layer in close juxtaposition to the overlying ectoderm. Subsequently, particular cell types within the mesoderm are specified along the anteroposterior and dorsoventral axes. The exact developmental pathways that guide the specification of different cell types within the mesoderm are ...
Gajović S - - 1998
In order to test the developmental potential of the mouse embryonic-stem-cell-derived embryoid bodies as chorioallantoic grafts, the embryoid bodies were transplanted to the chorioallantoic membrane (CAM) of the chick embryo. The graft implantation was achieved if the embryoid bodies were transferred to the CAM into the blood drop created by ...
Serbedzija G N - - 1998
In many vertebrates, removal of early embryonic heart precursors can be repaired, leaving the heart and embryo without visible deficit. One possibility is that this 'regulation' involves a cell fate switch whereby cells, perhaps in regions surrounding normal progenitors, are redirected to the heart cell fate. However, the lineage and ...
Ioana GABOREANU
The paper deals with the microscopic study of the leaves epiderm in Lathyrus latifolius L. and Lathyrus odoratus L. The transversal section through the foliar limb shows slight differences between the two faces of the limb and a weak development and differentiation of the mesophyll. The epidermic cells have rectangular ...
Zahavi N - - 1998
Localized zones of high cell proliferation have been thought to be important in determining several phases of axis formation at early stages of chick development. It was suggested that a developmental center, a center of cellular activity such as proliferation and movement, is located in the posterior half of the ...
Gasparian G - - 1998
There is no cell proliferation in very sparcely plated chick embryo cell cultures. Substituting conditioned medium or adding of ethanol-fixed homologous cells to the cultures accelerates cell colony growth. The mechanism for the mitogenic action of fixed cells is considered to be the contact stimulation of cell proliferation, and addition ...
Dupin E - - 1998
The avian embryo is a model in which techniques of experimental embryology and cellular and molecular biology can converge to address fundamental questions of development biology. The first part of the chapter describes two examples of transplantation and cell labeling experiments performed in ovo. Thanks to the distinctive histologic and ...
Williams B A - - 1997
Myotome and sclerotome precursor cells are derived, respectively, from cells in the dorsomedial and ventromedial regions of the somite. To assay changes in the specification of myotomal precursor cells during somite maturation, we implanted dorsomedial quadrant fragments, from staged quail somites, next to the notochords of host chick embryos, and ...
Wilson V - - 1997
A characteristic abnormality of chimeras composed of wildtype and T/T (Brachyury) mutant embryonic stem cells is the aggregation and accumulation of mutant cells in the primitive streak and its descendant, the tail bud (V. Wilson, L. Manson, W. C. Skarnes, and R. S. P. Beddington (1995). Development 121, 877-886). To ...
Shah S B - - 1997
In the chick embryo, the primitive streak is the first axial structure to develop. The initiation of primitive streak formation in the posterior area pellucida is influenced by the adjacent posterior marginal zone (PMZ). We show here that chick Vg1 (cVg1), a member of the TGFbeta family of signalling molecules ...
Eisenberg C A - - 1997
During the early stages of embryogenesis, the mesoderm gives rise to cells of the cardiovascular system which include cardiac myocytes and vascular endothelial and red blood cells. We have investigated the development of these cell phenotypes using aggregate cultures of avian blastoderm cells, which replicated mesodermal cell diversification. The cell ...
Kostakopoulou K - - 1997
Urodele amphibians are the only vertebrates that can regenerate amputated limbs, even as adults. However, we have previously shown that amputated chick wing bud stumps can be induced to ((regenerate)) and to form a complete set of correctly-patterned skeletal elements, following implantation of beads soaked in fibroblast growth factor-4 (FGF-4). ...
Golden J A - - 1997
We previously reported that retrovirally marked clones in the mature chick diencephalon were widely dispersed in the mediolateral, dorsoventral and rostrocaudal planes. The current study was undertaken to define the migration routes that led to the dispersion. Embryos were infected between stages 10 and 14 with a retroviral stock encoding ...
Fuhrmann S - - 1997
In this study we describe a large-scale screening cell ELISA protocol which is suitable for the characterization of exogenic factor effects in mixed central nervous system (CNS) culture. The main novelty of the assay is that it permits the measurement of cellular responses in populations comprising as little as 2-4% ...
Downs K M - - 1997
The murine allantois is the future umbilical component of the placenta. The base of the allantois is also thought to contain the future germ line. We have examined the fate and developmental potency of cells within the murine allantois during gastrulation. lacZ-expressing headfold-stage allantoises (approximately 8.0 days postcoitum; dpc) were ...
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