Structure and Function
Online ISSN : 1884-6084
Print ISSN : 1347-7145
ISSN-L : 1347-7145
Volume 9, Issue 2
Displaying 1-4 of 4 articles from this issue
Review
  • Takahashi K, Kwaan HC
    2011 Volume 9 Issue 2 Pages 45-58
    Published: 2011
    Released on J-STAGE: November 18, 2015
    JOURNAL FREE ACCESS
    The aim of our review article is to provide an understanding of how fibrin monomers are able to assemble into a visible network structure. It is based on well-known evidence of fundamental molecular studies, and on our results by a computer simulation as well as by calculation of logistic equation. The simulation was carried out by use of a physical process of percolation clustering programmed by Mathematica, and the calculation was carried out by Excel. Those mathematical models allowed us to present a novel dynamic mechanism of the fibrin coagulation. It consists of three fundamental steps. The first step occurs in liquid phase. Eight monomers assemble into protofibrils (0.05 nm in length, a module structure) followed by the second step; the association of those modules into a domain structure (0.6nm in length). The fibers in the domain keep growing with a concomitant two-way diversion, which is essential for the network formation. Then the final step takes place by the quick association of those domains until a visible network structure appears. Our computer simulation clearly demonstrated that there was a typical phase transition at the third step, which allowed a semi-solid crystallization of fibrins. Analysis by fast Fourier transform did show that there was no change in the components of the power spectra, while there was a change in the fractal dimensions before and after the phase transition. Confocal laser scanning microscopy demonstrated that there were many domains (nodes) and node-fiver-node structures. Thus the hypothetical steps described above would help to interpret the logistic growth of fibers as observed by photometric measurements. Therefore, our computer simulations, though it is a small-scale model, would provide the global understanding of the molecular assembly by self-organization.
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Original
  • Takashi Sato, Toshiaki Sato, Yumiko Konishi, Makoto Naganuma, Katsuhik ...
    2011 Volume 9 Issue 2 Pages 59-63
    Published: 2011
    Released on J-STAGE: November 18, 2015
    JOURNAL FREE ACCESS
    Effects of wrist flexion and extension on forearm pronation force were studied. The forces produced by maximal pronation (FMP) with the wrist relaxed (RP) , maximally flexed (FP) and maximally extended (EP) in the forearm 90° (supine), 60° (S60°), 30° (S30°), and 0° supinated (neutral) positions were measured in eight normal human subjects. The FMP of RP, FP, and EP were, respectively, 8.3±1.8 (mean±S.D.), 10.2±2.2, and 5.7±1.4 kg in the supine, 6.9±1.8, 8.0±2.3, and 4.8±1.4 kg in the S60°, 5.1±1.3, 4.8±1.3, and 3.3±1.0 kg in the S30°, and 3.5±0.8, 3.0±0.8, and 2.1±0.6 kg in the neutral position. The FMP of EP was small in every forearm position and the respective FMP of RP, FP, and EP decreased with changing the position from supine to neutral. Assuming the FMP of RP in each position as 100%, the FMP of FP was 124±7%, 116±8%, 95±23%, and 86±12%, and the FMP of EP was 68±10%, 71±17%, 64±14%, and 61±20%, respectively, in the supine, S60°, S30°, and neutral positions. The FMP of FP in the supine and S60° positions was larger and the FMP of EP in every position was smaller than RP. The results suggest that the force is reinforced by the flexion and weakened by the extension.
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  • Yumiko Konishi, Toshiaki Sato, Takashi Sato, Makoto Naganuma, Katsuhik ...
    2011 Volume 9 Issue 2 Pages 65-69
    Published: 2011
    Released on J-STAGE: November 18, 2015
    JOURNAL FREE ACCESS
    Changes of forearm supination force by changing flexion angle of the elbow joint were studied in eight normal human subjects. The subject sat on a chair and put the upper arm and forearm on a table with the shoulder 90° abducted, 0° flexed, and 0° rotated and the forearm 0° pronated (neutral position). The force (kg) of maximal supination was measured while elbow angle was changed from the maximum extension (0°) to 130° flexion by 10° step. The force was 3.9±1.2 (mean±S.D.), 4.5±1.2, 5.1±1.1, 6.2±1.1, 6.8±0.9, 7.7±1.1, 8.5±1.2, 8.3±1.4, 7.7±1.3, 7.3±0.9, 6.5±1.6, 6.0±1.7, 5.4±1.5, and 4.8±1.2 kg, respectively, at 0°, 10°, 20°, 30°, 40°, 50°, 60°, 70°, 80°, 90°, 100°, 110°, 120°, and 130° flexion. The force increased gradually from 0° to 60° flexion and then decreased very gradually from 70° to 130° flexion. The force at 60° flexion was 2.2 and 1.8 times as large as that at 0° and 130° flexion, respectively. Since m. biceps brachii is a strong supinator, the results of the present study should be caused by changes of the length of its muscle fibers and the angle of its distal tendon to the insertion with elbow flexion.
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  • Kyoko Abe, Tatsuo Shimada
    2011 Volume 9 Issue 2 Pages 71-78
    Published: 2011
    Released on J-STAGE: November 18, 2015
    JOURNAL FREE ACCESS
    To examine effects of cold and frozen storage on human milk morphologically, human milk stored in cold and frozen states was examined by light and transmission electron microscopy (TEM). Human milk collected by hand expression from the same person was stored at 4°C, -2°C, or -18°C for 3 hours (controls), 3 days, 6 days, or 1 month. For light microscopy examination, one drop of human milk (20 μm in size) warmed to 37°C was dropped into 2% osmium solution on a slide glass. For TEM examination, human milk was centrifuged and the yellow portion of the upper layer was collected. In control samples, lipid balls composed of lipid droplets were observed as small granules stained black with osmium. Relatively large lipid balls appeared in human milk samples stored at 4°C for 6 days and at -2°C for one month. Many lipid balls, of increased size, were observed in human milk stored frozen, regardless of the storage period. TEM revealed lipid balls in control samples to be spherical, varying in size from approximately 2 to 6 μm, and to be surrounded by lipid droplets and limiting membranes enclosing the droplets. Although lipid droplets and limiting membranes were destroyed in some lipid balls, these balls appeared to be well preserved in human milk stored at -2°C for one month. On the other hand, in human milk stored frozen, limiting membranes were destroyed and lipid droplet size was increased in most of the lipid balls.
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