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  • 1
    Electronic Resource
    Electronic Resource
    Twisted plywood structure of an alternating lamellar pattern in cellular cementum of human teeth (2000)
    Springer
    Anatomy and embryology 202 (2000), S. 25-30 
    Details
    ISSN: 1432-0568
    Keywords: Keywords Cementoblasts ; Collagen fibrils ; Lamellar structure ; Maceration ; Scanning electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Human cellular cementum was examined by scanning electron microscopy to elucidate the manner of the alternate lamellar pattern forming the cellular cementum. Specimens were demineralized, trimmed with a freezing microtome, and treated by NaOH-maceration. This procedure was chosen to avoid artifacts in the fibril arrangement, and to study the fibrous architecture in detail. For comparison, non-demineralized, polished and HCl-etched specimens were also prepared. In the NaOH-macerated specimens, the lamellar pattern of the cellular cementum conformed to the twisted plywood principle of bone lamellation with a periodic rotation of matrix fibrils resulting in an alternating lamellar pattern. In contrast, matrix fibrils were irregularly arranged without indication of rotation of matrix fibrils in the polished and etched specimens. Our results suggest that polishing and etching procedures cause damage to fibrils and fibril arrangement.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00008241
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  • 2
    Electronic Resource
    Electronic Resource
    Growth hormone secretion during longterm incubation of the pituitary of the Japanese eel, Anguilla japonica (1990)
    Springer
    Fish physiology and biochemistry 8 (1990), S. 159-165 
    Details
    ISSN: 1573-5168
    Keywords: Anguilla japonica ; growth hormone ; hypothalamic control ; osmotic effect ; somatostatin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Growth hormone (GH) secretion from organ-cultured pituitaries of the eel (Anguilla japonica) was studied during incubation in a defined medium for 2 weeks, using a homologous radioimmunoassay which does not distinguish between the two molecular forms of eel GH. The total amount of GH secreted increased gradually during the incubation period; so that the amount of GH released on day 14 was about 30 times greater than that on day 1. On day 14, the proportion of GH released relative to the total amount of GH present (the sum of GH released into the medium and residual content in the pituitary) was 96% and the amount produced on day 14 was 4 times greater than the content in the unincubated pituitary. Somatostatin (SRIF, 1.8 × 10-7 M) inhibited the increase in GH release. On day 7, the proportion of GH released by pituitaries treated with SRIF (28%) was less than that released by the control pituitary (91%). There was no significant difference in GH release between the pituitaries incubated in isotonic medium (300 mOsm) and those in hypotonic medium (240 mOsm) for 2 weeks except for the first 3 days, when the pituitaries in hypotonic medium secreted significantly greater amounts of GH than those incubated under isotonic condition. Hypertonic medium (350 mOsm) had no effect on GH release except for significant inhibition on days 6 and 14. When secretion of the two forms of GH (GH I and II) was examined after separation by polyacrylamide gel electrophoresis followed by densitometry, slightly more GH I tended to be secreted than GH II during the culture period, although the effects of SRIF and osmolality of the media on GH I release were similar to those on GH II. It is concluded that GH secretion and production in the eel is mainly under the inhibitory control of hypothalamus, and that osmolality has a minimum influence on the GH release.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00004443
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  • 3
    Electronic Resource
    Electronic Resource
    Simplified technique for the rapid determination of phytoplankton pigments by reverse-phase high-performance liquid chromatography (1993)
    Springer
    Journal of oceanography 49 (1993), S. 571-580 
    Details
    ISSN: 1573-868X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract A simplified technique for the rapid analysis of photosynthetic pigments in marine phytoplankton is described. The pigments extracted in N,N-dimethylformamide (DMF) are injected directly into the reverse-phase high-performance liquid chromatograph fitted with a photodiode array detector. We developed a new stepwise program; that is methanol-water (75∶25 v/v), methanol, methanol-acetone (80∶20) and methanol-acetone (65∶35). This program gives a good separation of at least 13 carotenoids, and 10 chlorophylls and their derivatives, completed within 20 min. The quantitative precision is high; the maximum standard error was less than 6%. The stability of pigments in DMF were also considered for application of this technique to the lab work on board the ship.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02237463
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  • 4
    Electronic Resource
    Electronic Resource
    Characteristics of photosynthetic pigment composition ofGymnodinium mikimotoi Miyake etKominami exOda (1992)
    Springer
    Journal of oceanography 48 (1992), S. 367-375 
    Details
    ISSN: 1573-868X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract Gymnodinium mikimotoi, a senior synonym ofGymnodinium nagasakiense often causes red tides in coastal waters of the western part of Japan. The photosynthetic pigment composition of two strains ofG. mikimotoi were analyzed by HPLC. They contain chlorophyllc 3 which has not been reported from dinoflagellates. They also contain fucoxanthin, 19'-hexanoyloxyfucoxanthin and 19'-butanoyloxyfucoxanthin as major carotenoides, which are anomalous in dinoflagellates. The pigment composition ofG. mikimotoi is compared with that ofGyrodinium aureolum which occur in European waters and is thought as a conspecific species withG. mikimotoi by several authors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02234015
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  • 5
    Electronic Resource
    Electronic Resource
    An improved method for the determination of phytoplankton chlorophyll using N, N-dimethylformamide (1990)
    Springer
    Journal of oceanography 46 (1990), S. 190-194 
    Details
    ISSN: 1573-868X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract Non volatile N, N-dimethylformamide (DMF) at room temperature is proposed as a new solvent for determining the chlorophylla in cultured and natural phytoplankton samples. Advantages of DMF compared to the solvents ordinarily used are (1) higher extraction efficiency, (2) rapid extraction time of 30 min, (3) simple extraction procedure requiring neither extra heating nor grinding, but soaking, and (4) a long stable life of chlorophylla (at least one month at 5°C in the dark).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02125580
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  • 6
    Electronic Resource
    Electronic Resource
    Effects of osmotic pressure on prolactin and growth hormone secretion from organ-cultured eel pituitary (1991)
    Springer
    Journal of comparative physiology 161 (1991), S. 147-153 
    Details
    ISSN: 1432-136X
    Keywords: Prolactin ; Growth hormone ; Osmotic pressure ; Pituitary ; Eel
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Effects of medium osmotic pressure on the release of prolactin (PRL) and growth hormone (GH) from the pituitary of the Japanese eel, Anguilla japonica, were examined during long-term organ culture in a defined medium. Prolactin and GH release, as measured by homologous radioimmunoassays, increased gradually for 7 days during incubation in isosmotic medium (295 mOsmolal). On day 7, 3 to 5 times more PRL and GH were released than on day 1. The amount of GH released was about 100 times greater than that of PRL. Electron microscopic observation revealed that both PRL and GH cells were in good condition after 7 days incubation. The reduction of medium osmotic pressure from 295 (isosmotic) to 235 or 260 mOsmolal significantly stimulated PRL release for 4 days. By contrast, an increase in medium osmolality from 295 to 360 mOsmolal was without effect. These treatments produced no significant alterations in GH release. The stimulatory effect of hyposmotic medium (235 mOsmolal) was no longer evident by 12 h after the pituitaries were returned to isosmotic medium. The isosmotic but low-sodium medium, prepared by adding mannitol to the hyposmotic medium, did not stimulate PRL release from the pituitary. These results indicate that plasma osmolality may be an important physiological factor controlling PRL release during freshwater adaptation of the eel.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00262877
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