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  • 1
    Electronic Resource
    Electronic Resource
    The localization and characterization of proteinases for the initial cleavage of porcine amelogenin (1992)
    Springer
    Calcified tissue international 51 (1992), S. 213-217 
    Details
    ISSN: 1432-0827
    Keywords: Porcine secretory enamel ; Degradation of amelogenin ; Proteinases ; 25kDa amelogenin ; Enzymography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary In the outermost layer of porcine-developing enamel adjacent to the ameloblasts in the secretory stage, the activities of two proteinases having molecular masses of 76 and 78kDa were detected by enzymography using gelatin as a substrate. On the other hand, high activities of known 30 and 34kDa proteinases were localized in the inner layer of the enamel. The 76kDa proteinase cleaved the carboxylterminal peptide of porcine 25kDa amelogenin to convert it to 20kDa amelogenin. The 78kDa proteinase also acted on the 25kDa amelogenin similarly, but its activity was weak. The results indicate that the 25kDa amelogenin synthesized and secreted by ameloblasts is converted to 20kDa amelogenin by the action of proteinase localized in the outermost layer of the secretory enamel, and then further degraded by the proteinases in the inner layer of the enamel associated with the increase of mineralization.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00334549
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  • 2
    Electronic Resource
    Electronic Resource
    On the mechanism of dimensional change of neutron irradiated graphite (1992)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 61 (1992), S. 1638-1640 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: In order to investigate the mechanism of large volume expansion of graphite due to neutron irradiation we have made in situ observation of damage structure of graphite with a high resolution transmission electron microscope (HRTEM). Both bending and randomizing the orientation of broken basal planes are proposed to be the origin for the large volume expansion of the irradiated graphite. It is also found that graphite easily loses its lattice ordering in the basal planes as demonstrated by halo rings in the (101¯0) diffraction pattern, while hardly losing its layered structure, i.e., (002) spots are retained.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.108436
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  • 3
    Electronic Resource
    Electronic Resource
    Action of metalloproteinases on porcine dentin mineralization (1994)
    Springer
    Calcified tissue international 55 (1994), S. 426-435 
    Details
    ISSN: 1432-0827
    Keywords: Dentin mineralization ; Enzymography ; Geatinases ; Proteoglycanases ; Protoglycans
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Samples containing predentin and mineralized dentin involving the mineralized front (newly formed dentin) were prepared by scraping developing porcine teeth after odontoblastic cell debris had been removed from the predentin surfaces. An extract was obtained separately from the matrices of predentin and of the newly formed dentin with a 4 M guanidine solution before and after demineralization with acetic acid solution. Enzymography detected 56 and 61 kDa gelatinases and 25 kDa proteoglycanase as neutral metalloproteinases in both extracts and proved them to be in an active form. Approximately half of the 56 and 61 kDa gelaunases binds to collagen fibers in predentin matrix. Three high molecular weight proteoglycans (70–85 kDa, 130–180 kDa, and 290 kDa) were found in the predentin matrix, but not in the newly formed dentin. The proteoglycanases in predentin degraded 290 kDa proteoglycan, if incubated together with calcium (Ca) ions. The results of this investigation indicate that active proteoglycanases with existed in the predentin perform no substantial work in proteoglycan degradation because the Ca ions are masked in the predentin matrix by coexisting proteoglycans. When mineralization occurs, however, they can degrade the proteoglycan at the mineralization front because excess Ca ions may be supplied via odontoblastic processes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00298556
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  • 4
    Electronic Resource
    Electronic Resource
    Porcine amelogenins (1994)
    Springer
    Calcified tissue international 54 (1994), S. 69-75 
    Details
    ISSN: 1432-0827
    Keywords: Porcine secretory enamel ; Porcine amelogenin ; Plasma desorption mass spectometry ; Amino acid sequence ; CNBr cleavage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Abstract Amelogenins were extracted from the thin outer layer of porcine secretory enamel and purified by gel filtration and reverse-phase HPLC. The results of amino acid sequencing of the purified porcine amelogenins indicated the presence of at least four prototype amelogenins translated from alternatively spliced transcripts. The results of mass spectroscopy of the CNBr-cleaved peptides derived from the 25kDa amelogenin indicated that porcine 25kDa amelogenin is neither phosphorylated nor glycosylated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00316293
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  • 5
    Electronic Resource
    Electronic Resource
    Enamelins in the newly formed bovine enamel (1993)
    Springer
    Calcified tissue international 53 (1993), S. 257-261 
    Details
    ISSN: 1432-0827
    Keywords: Bovine enamelin ; Amelogenin ; Newly formed enamel ; Western blot
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary The possibility of using the antisera raised in rabbits against the porcine 25 kDa amelogenin, 32 and 89 kDa enamelins, and the 13–17 kDa nonamelogenin for the differentiation and identification of the protein components in bovine immature enamel was examined. Although the immunoreactivities of these antisera against bovine enamel proteins were weaker than those against the porcine proteins, it was found that these antisera could differentiate and demonstrate immunohistochemically a characteristic distribution of three different kinds of enamel protein components in the bovine secretory stage enamel similar to those observed in the porcine immature enamel. Of the several high molecular weight proteins being reactive to the anti-porcine 32 and 89 kDa enamelin sera, the 130 kDa protein, having the highest molecular weight, was extracted and purified from the bovine enamel sample which was obtained by peeling approximately 30-μm thickness of the outermost layer of the secretory stage enamel. The amino acid composition of the 130 kDa protein was similar to the known bovine enamelins, and was rich in aspartic acid, glutamic acid, proline, and glycine. The results could suggest that the enamelins of lower molecular weight than this protein, which are found in the bovine secretory stage enamel, are derived from this precursor protein.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01320911
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  • 6
    Electronic Resource
    Electronic Resource
    Symptoms of contruction workers exposed to whole body vibration and local vibration (1992)
    Springer
    International archives of occupational and environmental health 64 (1992), S. 347-351 
    Details
    ISSN: 1432-1246
    Keywords: Construction machinery ; Whole body vibration ; Local vibration ; Low back pain ; Raynaud's phenomenon
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary To study the effects of construction machinery operation on subjective symptoms, a questionnaire survey was caried out among construction machinery operators by a self-reporting method. Subjects were 184 power shovel operators, 127 bulldozer operators, 44 forklift operators as operator groups, and 44 office workers as a control. Their ages were in a range of 30–49 years. The questionnaire contained 20 symptoms referring to fatigue, digestive problems, and upper or lower limbs or back problems. The prevalence rate and symptom characteristics were examined. The dominant symptoms of the operator groups were stiff shoulder, low back pain, and stomack symptoms. The prevalence rate of low back pain was significantly different between forklift operators and controls. No significant differences were found in the symptoms of upper limbs and fingers between operator groups and controls. The prevalence of Raynaud's phenomenon was 0.5%–2.3% in the operator groups and 2.3% in the control group.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00379545
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  • 7
    Electronic Resource
    Electronic Resource
    Immunochemical and immunohistochemical studies, using antisera against porcine 25 kDa amelogenin, 89 kDa enamelin and the 13–17 kDa nonamelogenins, on immature enamel of the pig and rat (1991)
    Springer
    Histochemistry and cell biology 96 (1991), S. 129-138 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Enamel proteins were extracted from the newly formed layer of immature porcine enamel, and the 25 kDa amelogenin, 89 kDa enamelin and 13–17 kDa nonamelogenins were purified. Specific antisera were raised against these proteins. Antibodies specific to the C-terminal region (residues 149–173) of the 25 kDa amelogenin were generated by absorption of the anti-25 kDa amelogenin serum with 20 kDa amelogenin, which contains residues 1–148 of the antigen. Immunoelectrotransfer blotting of the extracted porcine enamel proteins showed that the anti-25 kDa amelogenin serum recognized the 25 kDa and other low and high molecular weight amelogenins. The C-terminal specific anti-25 kDa amelogenin serum reacted only with amelogenins having molecular weights over 23 kDa. The anti-89 kDa enamelin serum recognized the 89 kDa enamelin and lower molecular weight proteins, but neither the amelogenins nor the 13–17 kDa nonamelogenins. The antiserum against the 13–17 kDa nonamelogenins showed no cross reactivity to the 89 kDa enamelin, but recognized higher molecular weight nonamelogenins. In immunohistochemical preparations of the porcine tooth germs, the 25 kDa amelogenin-like immunoreactivity over immature enamel decreased in a gradient from the enamel surface to the middle layer. In the inner layer immunoreactivity was concentrated over the prism sheaths. The C-terminal specific 25 kDa amelogenin-like immunoreactivity was intense at the outer layer of immature enamel and decreased sharply toward the middle layer. Prism sheaths were intensely stained by the antiserum to the 13–17 kDa nonamelogenins. The 89 kDa enamelin-like immunoreactivity over enamel prisms was intense at the outer layer and decreased toward the middle layer. Staining by the anti-89 kDa enamelin serum of prism sheaths was faint. In immature rat incisor enamel, the C-terminal specific 25 kDa amelogenin antiserum demonstrated a staining pattern similar to that in the immature enamel of the pig. Distinct 13–17 kDa nonamelogenin-like and 89 kDa enamelin-like immunoreactivities were found especially in the layer adjacent to the Tomes' process. We conclude that some enamel proteins are degraded soon after their secretion from the secretory ameloblast in the rat and the pig. The specific enamel proteins which reacted with the antiserum to the 13–17 kDa nonamelogenins seem to be involved with the formation of prism sheaths in immature porcine enamel, but not in rat incisor enamel.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00315983
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