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  • 1
    ISSN: 1432-0568
    Keywords: Key words Colchicine ; Olfactory epithelium ; Vomeronasal organ ; Apoptosis ; Proliferation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The cytotoxic agent colchicine induced apoptotic cell death and subsequent regeneration in the mouse olfactory epithelium and vomeronasal organ. The TUNEL method revealed the presence of many apoptotic bodies in the middle to basal region of the septal olfactory epithelium and vomeronasal organ near the boundary of the respiratory epithelium at 1 day after a single i.p. injection of colchicine (4 mg/kg b.w.). In some regions of the third and the fourth nasal turbinates, massive apoptosis was observed in the olfactory epithelium. Electron micrographs of the septum showed that immature olfactory cells and globose basal cells were killed by the colchicine and had been phagocytized by the supporting cells and macrophages. In the vomeronasal organ, immature sensory cells and precursors died in response to the colchicine. In response to cell death, active proliferation of precursor cells (globose basal cells) and subsequent regeneration of olfactory cells occurred in the olfactory epithelium and vomeronasal organ. Incorporation of the mitotic tracer BrdU by precursor cells reached its peak at 4 days after colchicine treatment in the vomeronasal organ, and at 6 to 7 days in the olfactory epithelium; however, in some regions in the third and the fourth nasal turbinates, where many olfactory cells and globose basal cells had died by colchicine effect, the regeneration did not occur even in 1 month, forming the epithelium of only supporting cells and horizontal basal cells. In the next month, these regions became normal olfactory epithelium. This suggests that the globose basal cells in the surrounding normal olfactory epithelium might invade these regions to give rise to the olfactory cells.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 187 (1993), S. 209-219 
    ISSN: 1432-0568
    Keywords: NCAM ; Tooth ; Tooth germ ; Development ; Mouse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract NCAM, the neural cell adhesion molecule, was immunolocalized in the mandibular first molar tooth germ of the mouse. NCAM was first detected in the tooth germ of the late bud stage, where only the cells in the outer part of the condensed mesenchyme (primitive dental follicle) exhibited faint immunoreactivity. The entire dental follicle was intensely immunostained for NCAM from cap stage to the stage when root formation started. During root formation, NCAM disappeared from the follicular tissue surrounding the cervical root as well as from the part covering the crown top. This loss of NCAM proceeded in the direction of the root apex, but even after the tooth had achieved functional occlusion, NCAM was still expressed by the mesenchymal cells adjacent to the root apex. On the other hand, NCAM was negative in the dental papilla until birth. After birth, NCAM-immunoreactivity appeared in the basal portion of the dental papilla, but this NCAM-positive area gradually diminished in width during the root elongation. Instead, another NCAM-positive zone appeared in the core of the pulp during root formation. Even in the tooth that had already erupted, the pulp core contained cells that were strongly positive for NCAM immunostaining. In addition to its expression in the above two mesenchymal cell lineages, NCAM was transiently expressed by epithelial components of the tooth germ, some of the cells of the dental lamina and the enamel organ. The results suggest that NCAM participates in several processes of tooth development.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 188 (1993), S. 13-20 
    ISSN: 1432-0568
    Keywords: NCAM ; Molar ; Tooth germ ; Development ; Mouse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Distribution of the neural cell adhesion molecule (NCAM) during the development of the mandibular second- and third-molars of the mouse was studied by indirect immunofluorescence techniques. At the initial stage, NCAM was intensely expressed by the mesenchymal cells surrounding the dental lamina, and by the cap stage NCAM expression by the mesenchymal cells became restricted to the dental follicle. After that, in addition to the follicular mesenchyme, some cells in the basal part of the dental papilla showed NCAM-immunoreactivity for a while after the hard tissue formation had started. During root formation, the follicular cells lost NCAM first from the level of the cervical root and later from the coronal part, while an additional NCAM positive area appeared deep in the dental papilla. Even after the teeth had erupted, NCAM was expressed in the tissue surrounding the apical root and in the pulp core. During the initial and bud stages, the pattern of NCAM expression in the second and third molars was different from that in the first molar, where NCAM was found only after the late bud stage; while from the cap stage onward, it changed in the same sequence as in the first molar. The different pattern of NCAM expression implies that there is a difference in developmental events between the early stages of the first and the other two molars. On the other hand, the common sequence of NCAM expression in the tooth germs later than the cap stage suggests that NCAM plays an essential role in the formation of the basic structure of the teeth and periodontal tissues.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Anatomy and embryology 196 (1997), S. 447-455 
    ISSN: 1432-0568
    Keywords: Key words γδ T cell ; Langerhans cell ; Taste bud ; Denervation ; Tongue
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  The distribution of dendritic (Langerhans) cells and lymphocytes in rat circumvallate and foliate papillae was examined by immunohistochemistry and electron microscopy. Light microscopic immunohistochemistry using anti-OX62 antibody, which recognizes both γδ T lymphocytes and dendritic cells, showed that many OX62-immunoreactive cells had invaded into the trench wall epithelium from the connective tissue at 6 days after sectioning of the glossopharyngeal nerves. The presence of OX62-immunoreactive cells in the epithelium was observed up to 17 days after the denervation, by which time the taste buds had disappeared from the trench wall. The OX62-positive cells were again observed in the connective tissue at 24 and 40 days when taste buds regenerated. The local circulation of OX62-positive cells between the epithelium and connective tissue is suggested. Most of the OX62-positive cells in the epithelium of circumvallate and foliate papillae were suggested to be γδ T cells, since they were round or spindle-shaped. Electron micrographs of OX62-positive cells also indicated that they were lymphocytes. Furthermore, they expressed CD3 but lacked CD4 and CD8 surface markers. A few dendritic cells, which reacted with anti-OX6 antibody, were observed in the circumvallate and foliate papillae in the control and denervated animals, and they were irregular in shape with long cytoplasmic processes. Electron micrographs taken at 6 days showed that the dendritic cells, which were characterized by the presence of Birbeck granules in the cytoplasm, were in contact with lymphocytes. The finding suggests that γδ T lymphocytes and dendritic cells in the rat circumvallate and foliate papillae interact with each other to respond to changes such as the presence or absence of taste buds in the epithelium.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 286 (1996), S. 55-62 
    ISSN: 1432-0878
    Keywords: Key words: Taste bud ; Denervation ; Apoptosis ; Cell death ; TUNEL method ; Glossopharyngeal nerve ; Circumvallate papilla ; Mouse (dd)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. Apoptotic cells in the taste buds of mouse circumvallate papillae after the sectioning of bilateral glossopharyngeal nerves were examined by the method of DNA nick-end labeling (TUNEL), together with standard electron microscopy. The taste buds decreased in number and size 3–11 days after denervation and disappeared at 11 days. The TUNEL method revealed only a few positively stained nuclei in normal taste buds but, in those of mice 1–5 days after denervation, the number of positive nuclei had increased to 3–5 times that of taste buds from normal mice. Electron-microscopic observation after denervation demonstrated taste bud cells containing condensed and fragmentary nuclei in a cytoplasm with increased density. The results show that taste bud cells under normal conditions die by apoptosis at the end of their life span, and that gustatory nerve sectioning causes apoptosis of taste bud cells with taste buds decreasing in number and ultimately disappearing.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-0878
    Keywords: Olfactory epithelium Supporting cells Horizontal basal cells Three-dimensional reconstruction Apoptosis BrdU immunohistochemistry Mouse (DdY)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. The olfactory epithelium of mice generally consists of olfactory cells, progenitors of olfactory cells (globose basal cells), supporting cells, and horizontal basal cells. However, in the dorsal fossa (the roof) of the posterior nasal cavity of mice, we found seven epithelial patches consisting of only non-neuronal cell types, i.e., supporting cells and horizontal basal cells, among the normal olfactory epithelium. The supporting cells occupied three or four layers in the apical to middle regions; in the basal region, horizontal basal cells were localized in a single row adjacent to the basement membrane. Bowman's gland ducts were also present in the epithelium. Neuronal cells (olfactory cells and globose basal cells) were totally absent. The ultrastructure of the supporting cells, horizontal basal cells, and Bowman's glands was essentially similar to that in the normal olfactory epithelium. In the early postnatal period (P1–P7), cell types in the epithelium were the same as those in the normal olfactory epithelium. From P10 to P21, olfactory cells and globose basal cells had disappeared from the olfactory epithelium. At this period, the number of TUNEL-positive cells was significantly higher than that in the surrounding olfactory epithelium; ultrastructurally, many apoptotic figures were observed. This suggests that the epithelium consisting of supporting cells and horizontal basal cells is generated by the apoptotic death of olfactory cells and globose basal cells during postnatal development.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-0878
    Keywords: Taste bud Colchicine Apoptosis Epithelial cell Circumvallate papilla Microtubule Mouse (dd)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. Apoptotic cells in the taste buds and epithelia of mouse circumvallate papillae after colchicine treatment were examined by the methods of in situ DNA nick-end labeling, immunocytochemistry, and electron microscopy. After colchicine treatment, numerous positive cells appeared in the taste buds by DNA nick-end labeling, and some epithelial cells in the basal and suprabasal layers in and around the circumvallate papillae also revealed positive staining. Condensed and fragmented nuclei with a high density were occasionally found in the taste bud cells and in the basal and suprabasal layer epithelial cells by electron-microscopic observation. An immunocytochemical reaction for tubulin revealed weak staining in taste bud cells, because of the depolymerization of microtubules, and a decrease of the microtubules in the taste bud cells was observed by electron microscopy. These results indicate that colchicine treatment of mice induces the apoptosis of taste bud and epithelial cells in the circumvallate papillae and dorsal epithelial cells around the circumvallate papillae.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 226 (1982), S. 327-335 
    ISSN: 1432-0878
    Keywords: Xenopus ; Spleen ; B-lymphocyte ; Immunofluorescence ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary An indirect immunofluorescence study of the frozen sections of the spleen of an anuran amphibian, Xenopus laevis, showed that lymphocytes bearing a small amount of immunoglobulin (Ig) were localized mostly in the white pulp of non-immunized toads. There were fewer fluorescent cells in the red pulp. In the toads hyperimmunized with human gamma globulin (HGG), cells with strong cytoplasmic fluorescence increased significantly in the outer part of the white pulp. Electron microscopy of spleens from these toads showed that plasma cells at different stages of maturation were abundant in the white pulp, whereas in the red pulp, a smaller number of maturer plasma cells were observed. These results indicate that, in contrast with its mammalian counterpart, the splenic white pulp of this anuran is the site where thymusin-dependent lymphocytes commence blast formation and transformation into plasma cells.
    Type of Medium: Electronic Resource
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