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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of periodontal research 24 (1989), S. 0 
    ISSN: 1600-0765
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: β-TCP was implanted in surgically prepared alveolar bone defects on the mesial side of the upper canine. The dogs that we used were sacrificed after 5 weeks, fixed by perfusion, and the β-TCP resorbing cells were examined ultrastructural-ly and histochemically, with the following results: (1) β-TCP was resorbed by macrophages and multinucleated giant cells. (2) Mitochondria, vacuoles and Golgi apparatus were abundant in β-TCP-resorbing multinucleated giant cells that possessed neither ruffled borders nor clear zones. (3) The addition of tartric acid inhibited acid phosphatase activity in the cytoplasm of the multinucleated giant cells and macrophages.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1440-1797
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Summary: To evaluate the effect of 24R,25-dihydroxyvitamin D3 (24,25D) on uraemic bone disease, we treated the model rats of mild renal failure either with 0.5 μg/kg bodyweight (BW) of 24,25D, or with 5 μg/kg BW of 24,25D, or with 0.01 μg/kg BW of 1,25-dihydroxyvitamin D3 (1,25D), or with 0.01 μg/kg BW of 1,25D and 0.5 μg/kg BW of 24,25D, or with vehicle alone, given orally for 16 weeks. the examination of bone histology revealed extreme acceleration of bone turnover and decreased trabecular bone volume with elevated serum parathyroid hormone (PTH) level in vehicle-treated uraemic rats compared with those of sham-operated rats. Treatment with 24,25D (5 μg/kg BW) not only ameliorated high-turnover bone disease as with 1,25D, but also prevented the reduction of trabecular bone volume without any changes of serum PTH levels, suggesting the possible direct effect of 24,25D on the bone. Our data suggest 24,25D may be another useful agent for the treatment of high-turnover bone disease caused by secondary hyperparathyroidism in chronic renal failure, with less suppression of parathyroid function.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1440-1797
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Summary: We determined the distribution of Spot 35-calbindin-D28K, a vitamin-D dependent calciumbinding protein, in rat kidney using histochemical methods and compared it with the distribution of Ca2+-ATPase activity. Spot 35-calbindin-D28K immunoreactivity was localized in the cytosol of urinary epithelial cells in distal convoluted tubules (DCT), connecting tubules (CNT) and cortical collecting ducts (CCD), identifying the physiologically confirmed site of active transcellular calcium transport. In the cytosol, the immunoreactivity was clustered near the luminal plasma membrane and around the mitochondria. These findings indicated that Spot 35-calbindin-D28K seemed to have a cytosolic calcium buffering effect in the urinary tubular epithelial cells. Enzyme histochemical analysis showed that Ca2+-ATPase activity was localized at the basolateral plasma membrane of distal nephron segments and was strongest at the cortical thick ascending limb of Henle (CTAL), including the macula densa portion. Ca2+-ATPase activity was not evident in DCT, CNT or CCD. Strong Ca2+-ATPase activity and Spot 35-calbindin-D28K immunoreactivity did not coexist in a urinary tubular cell.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Calcified tissue international 51 (1992), S. S21 
    ISSN: 1432-0827
    Keywords: Ipriflavone ; Bone resorption ; Osteogenesis ; Confocal scanning laser microscope
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Bone labeling, histochemical, and fine structural studies were performed in order to clarify the effects of ipriflavone (IP) on rat bone tissuein vivo andin vitro. Labeling experiments showed a slight increase in bone formation during 3 days' administration. It was also noted that many osteoclasts detached from the bone surface at 1, 2, and 6 hours after administrationin vivo. In addition, irregular localization of tartrate-resistant acid phosphatase (TRACPase) activity was observed in osteoclasts. Fine structurally, IP-treated osteoclasts exhibited irregularity in their ruffled borders, as reported in calcitonin administration, and many enlarged rough endoplasmic reticuli and vacuoles were observed. However, osteoclasts at 12 hours after administration, as well as the control, indicated recovery features from the effect of IP. Osteoblast proliferation and differentiation led to increasing alkaline phosphatase activity (ALPase) with time as well as the development of rough endoplasmic reticuli and Golgi apparatus with well-developed fine structure. These findings imply active synthesis of bone matrix. In ourin vitro experiment, osteoclasts and osteoblasts displayed histochemical and fine structural characteristics Similar to those observed in ourin vivo experiment. Moreover, fewer TRACP-positive mononuclear cells were observed after 24-hour culture with IP than with the control. These results suggest that IP inhibits directly and/or indirectly differentiation and activity of osteoclasts and also promotes differentiation of osteoblast-lineage cells and their bone-forming activity.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-0827
    Keywords: Rat ; Incisor ; Amelogenesis ; Acid phosphatase ; Ferritin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary Acid phosphatase was localized in rat incisor ameloblasts without prior decalcification. Whenβ-glycerophosphate was used as the substrate, an intense reaction was observed in the supranuclear region of the secretory ameloblasts. But the reaction was dramatically reduced at the transitional stage and was very weak in the maturation ameloblasts. Whenp-nitrophenylphosphate was the substrate, the reaction product was consistently seen in the Golgi cisternae and the vesicular components of the ameloblasts at all stages of enamel development. These observations suggest that there are two acid phosphatases in ameloblasts. One is in the secretory ameloblasts and the other in the transition and maturation ameloblasts. X-ray micro-analyses for Fe and Pb showed that Fe and acid phosphatase were in the ferritin-containing vesicles at the later stage of enamel maturation. This evidence suggests that ferritin is digested in these vesicles for the release of the Fe pigment to the enamel. An increase in the number of intercellular bridges between ameloblasts was correlated with the dramatic decrease in height of ameloblasts at the pigment release stage. The ameloblast membranes were acid phosphatase positive at the intercellular bridges whenp-nitrophenylphosphate was the substrate. This activity may be involved in the reduction in the surface area of the ameloblast membranes.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Histochemistry and cell biology 107 (1997), S. 183-191 
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Immunolocalization of tissue non-specific alkaline phosphatase (TNAP) was examined in murine tissues, employing a specific antiserum to TNAP on frozen sections, 50-μm tissue slices, and paraffin sections. TNAP was detected at high levels in hard tissues including bone, cartilage, and tooth. In bone tissue, the TNAP immunoreactivity was localized on the entire cell surface of preosteoblasts, as well as the basolateral cell membrane of osteoblasts. It was also localized on some resting chondrocytes and most of the proliferative and hypertrophic cells in cartilage. In the incisor, cells of the stratum intermedium, the subodontoblastic layer, the proximal portion of secretory ameloblasts, and the basolateral portion of odontoblasts showed particularly strong immunoreactivity. Immunoreactivity was observed in other soft tissues, such as the brush borders of proximal renal tubules in kidney, on cell membrane of the biliary canalicula in liver and in trophoblasts in the placenta. These immunolocalizations were quite similar to enzyme histochemical localizations. However, neither the submandibular gland nor the intestine, which both exhibited alkaline phosphatase activity by enzyme histochemistry, revealed immunoreactivity for TNAP. Therefore, immunocytohistochemical studies for TNAP enabled us to localize the TNAP isozyme, thus distinguishing it from other isozymes.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  Amelogenins are the most abundant constituent in the enamel matrix of developing teeth. Recent investigations of rodent incisors and molar tooth germs revealed that amelogenins are expressed not only in secretory ameloblasts but also in maturation ameloblasts, although in relatively low levels. In this study, we investigated expression of amelogenin in the maturation stage of porcine tooth germs by in situ hybridization and immunocytochemistry. Amelogenin mRNA was intensely expressed in ameloblasts from the differentiation to the transition stages, but was not detected in maturation stage ameloblasts. C-terminal specific anti-amelogenin antiserum, which only reacts with nascent amelogenin molecules, stained ameloblasts from the differentiation to the transition stages. This antiserum also stained the surface layer of immature enamel at the same stages. At the maturation stage, no immunoreactivity was found within the ameloblasts or the immature enamel. These results indicate that, in porcine tooth germs, maturation ameloblasts do not express amelogenins, suggesting that newly secreted enamel matrix proteins from the maturation ameloblast are not essential to enamel maturation occurring at the maturation stage.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1432-0878
    Keywords: Odontoclast Deciduous teeth Apoptosis Bisphosphonate Ultrastructure Rabbit
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. Since odontoclasts share similar characteristics with osteoclasts, this study has examined whether odontoclasts exhibit cytological alteration after treatment with bisphosphonate, which induces apoptosis of osteoclasts. After the administration of bisphosphonate to 6-day-old rabbits, many odontoclasts detached from the dentine surface of the deciduous teeth, resulting in the reduction of tartrate-resistant acid phosphatase (TRAPase) and immunoreactivity for cathepsin K. Transmission electron microscopy revealed a number of odontoclasts showing poorly developed or a lack of ruffled borders, a Golgi apparatus markedly reduced in size, and numerous cytoplasmic vesicles. The bisphosphonate-treated odontoclasts displayed fragmented DNA in the pyknotic nuclei evidenced by terminal deoxynucleotidyl-transferase-mediated dUTP-biotin nick-end labeling, indicating that bisphosphonate can induce apoptosis of the odontoclasts. Ultrastructural observations of the apoptotic odontoclasts revealed condensed heterochromatin at the margin of the nuclear envelope, assembled arrays of rough endoplasmic reticulum, and many vacuoles and vesicles. Some apoptotic odontoclasts showed ladder-like structures between the adjacent nuclear envelopes, enlargement of the nuclear envelopes, and the formation of a ribosome-like granular structure in the nuclei. Thus, odontoclasts are able to undergo apoptosis after bisphosphonate treatment; this results in cytological alterations, including reduced resorption activity and the inhibition of protein synthesis/transport as indicated by the diminished TRAPase and cathepsin K and the poorly developed Golgi apparatus, respectively. Nuclear alteration as evidenced by the appearance of ladder-like and ribosome-like structures was characteristic of apoptotic odontoclasts.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1432-0878
    Keywords: CD44, adhesion molecule ; Bone ; Osteoclasts ; Osteocytes ; Immunohistochemistry ; Confocal laser scanning microscopy ; Electron microscopy ; Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract CD44 is a multifunctional adhesion molecule that binds to hyaluronic acid, type I collagen, and fibronectin. We have studied the immunohistochemical localization of CD44 in bone cells by confocal laser scanning microscopy and transmission electron microscopy in order to clarify its role in the cell-cell and/or cell-matrix interaction of bone cells. In round osteoblasts attached to bone surfaces, immunoreactivity is restricted to their cytoplasmic processes. On the other hand, osteocytes in bone matrices show intense immunoreactivity on their plasma membrane. Intense immunoreactivity for CD44 can be detected on the basolateral plasma membranes of osteoclasts. There is considerably less reactivity observed in the area of the plasma membrane that is in direct contact with bone. The pre-embedding electron-microscopical method has revealed that CD44 is mainly localized on the basolateral plasma membrane of osteoclasts. However, the ruffled border and clear zone show little immunoreactivity. A CD44-positive reaction can be detected on both plasma membranes in the contact region between osteoclasts and osteocytes. These findings suggest that: 1) cells of the osteoblast lineage express CD44 in accordance with their morphological changes from osteoblasts into osteocytes; 2) osteoclasts express CD44 on their basolateral plasma membrane; 3) CD44 in osteoclasts and osteocytes may play an important role in cell-cell and/or cell-matrix attachment via extracellular matrices.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1432-0878
    Keywords: Key words: CD44 ; adhesion molecule ; Bone ; Osteoclasts ; Osteocytes ; Immunohistochemistry ; Confocal laser scanning microscopy ; Electron microscopy ; Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract. CD44 is a multifunctional adhesion molecule that binds to hyaluronic acid, type I collagen, and fibronectin. We have studied the immunohistochemical localization of CD44 in bone cells by confocal laser scanning microscopy and transmission electron microscopy in order to clarify its role in the cell-cell and/or cell-matrix interaction of bone cells. In round osteoblasts attached to bone surfaces, immunoreactivity is restricted to their cytoplasmic processes. On the other hand, osteocytes in bone matrices show intense immunoreactivity on their plasma membrane. Intense immunoreactivity for CD44 can be detected on the basolateral plasma membranes of osteoclasts. There is considerably less reactivity observed in the area of the plasma membrane that is in direct contact with bone. The pre-embedding electron-microscopical method has revealed that CD44 is mainly localized on the basolateral plasma membrane of osteoclasts. However, the ruffled border and clear zone show little immunoreactivity. A CD44-positive reaction can be detected on both plasma membranes in the contact region between osteoclasts and osteocytes. These findings suggest that: 1) cells of the osteoblast lineage express CD44 in accordance with their morphological changes from osteoblasts into osteocytes; 2) osteoclasts express CD44 on their basolateral plasma membrane; 3) CD44 in osteoclasts and osteocytes may play an important role in cell-cell and/or cell-matrix attachment via extracellular matrices.
    Type of Medium: Electronic Resource
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