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  • 1
    Electronic Resource
    Electronic Resource
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 255-257 (Sept. 1997), p. 695-697 
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1365-2958
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Medicine
    Notes: The expression of the infC gene encoding translation initiation factor IF3 is negatively autoregulated at the level of translation, i.e. the expression of the gene is derepressed in a mutant infC background where the IF3 activity is lower than that of the wild type. The special initiation codon of infC, AUU, has previously been shown to be essential for derepression in vivo. In the present work, we provide evidence that the AUU initiation codon causes derepression by itself, because if the initiation codon of the thrS gene, encoding threonyl-tRNA synthetase, is changed from AUG to AUU, its expression is also derepressed in an infC mutant background. The same result was obtained with the rpsO gene encoding ribosomal protein S15. We also show that derepression of infCthrS, and rpsO is obtained with other ‘abnormal’ initiation codons such as AUA, AUC, and CUG which initiate with the same low efficiency as AUU, and also with ACG which initiates with an even lower efficiency. Under conditions of IF3 excess, the expression of infC is repressed in the presence of the AUU or other ‘abnormal’ initiation codons. Under the same conditions and with the same set of ‘abnormal’ initiation codons, the repression of thrS and rpsO expression is weaker. This result suggests that the infC message has specific features that render its expression particularly sensitive to excess of IF3. We also studied another peculiarity of the infC message, namely the role of a GC-rich sequence located immediately downstream of the initiation codon and conserved through evolution. This sequence was proposed to interact with a conserved region in 16S RNA and enhance translation initiation. Unexpectedly, mutating this GC-rich sequence increases infC expression, indicating that this sequence has no enhancing role. Chemical and enzymatic probing of infC RNA synthesized in vitro indicates that this GC-rich sequence might pair with another region of the mRNA. On the basis of our in vivo results we propose, as suspected from earlier in vitro results, that IF3 regulates the expression of its own gene by using its ability to differentiate between ‘normal’ and ‘abnormal’ initiation codons.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1433-044X
    Keywords: Key words PLLA • Biofix • Ankle fracture • Sterile sinus ; Schlüsselwörter PLLA • Biofix • Knöchelfraktur • Sterile Knochenhöhle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Es wurde eine randomisierte klinische Prospektivstudie durchgeführt, um den Einsatz von selbstverstärkten absorbierbaren Verbindungen (Biofix) zur Fixierung von Knöchelfrakturen zu bewerten. Mit dieser Studie sollte nachgewiesen werden, daß bei der Fixierung mit Biofix-Stäben und Schrauben die gleichen Ergebnisse erzielt werden wie bei der standardmäßigen AO-Fixierung. Die Biofix-Stäbe und Schrauben bieten folgende Vorteile: Kostensenkung, da keine Nachoperation erforderlich ist, Verhinderung von Spannungsabschirmung und dadurch Reduzierung des Risikos von Knochenporosität. Im Rahmen der Studie wurden Patienten im Alter zwischen 16 und 75 Jahren mit geschlossenen Nichtsplitterfrakturen des Malleolus lateralis und/oder medialis und Luxation der Frakturfragmente von über 2 mm untersucht; 22 Patienten wurden mit Biofix-Stäben und Schrauben behandelt, während die 19 Patienten umfassende Kontrollgruppe mit einer Standardtechnik behandelt wurde. Nach 3, 6 und 12 Monaten wurden Röntgenaufnahmen gemacht. Gleichzeitig erfolgte eine Bewertung der funktionellen Ergebnisse gemäß den Kriterien nach Olerud und Molander. 2 Patienten wurden aus nichtmedizinischen Gründen aus der Testgruppe herausgenommen; 22 vor 2 oder mehr Jahren operierte Patienten (12 aus der Biofix-Gruppe, 10 aus der AO-Gruppe) wurden kontaktiert, um festzustellen, ob sich seit der letzten Untersuchung Komplikationen ergeben haben. In 4 Fällen brach während des Einsetzens eine Biofix-Schraube kurz hinter dem Kopf ab. Das hatte keine negativen Auswirkungen auf die Fixierung der Fraktur. Es traten keine frühen postoperativen Komplikationen auf. Die funktionellen und radiologischen Ergebnisse waren in beiden Gruppen gleich. In 3 Fällen entwickelte sich eine sterile Knochenhöhle auf der Seite, auf der die Schrauben eingesetzt wurden. Biofix-Stäbe und Schrauben aus Polymilchsäure stellen eine gute Alternative für die Fixierung von Knöchelfrakturen dar. Die Verwendung von resorbierbarem Frakturfixierungsmaterial bietet den Vorteil, daß keine Nachoperation zur Entfernung des osteosynthetischen Materials erforderlich ist. Die Langzeitergebnisse sind gut. Es besteht jedoch die Möglichkeit, daß sich eine Gewebereaktion auf das resorbierbare Material entwickelt.
    Notes: Summary A prospective randomized clinical trial was performed to evaluate the use of self-reinforced absorbable composites (Biofix) in the fixation of ankle fractures. The aim of this study was to demonstrate that fixation with Biofix rods and screws is as good as the standard A. O. fixation. The benefits of Biofix rods and screws are: a reduction in costs since no secondary operation is needed, prevention of stress-shielding and thereby diminishing the risk of bone porosity. Patients aged between 16 and 75 years old with closed, non-comminuted fractures of the lateral and/or medial malleolus and dislocation of the fracture fragments greater thean 2 mm were included in the study. 22 patients were treated with Biofix rods and screws and the control group of 19 patients with a standard technique. After 3, 6 and 12 months, rontgenograms were taken. At the same time functional results were evaluated following the criteria of Olerud and Molander. Two patients were withdrawn from the trial for non-medical reasons. 22 patients (12 from the Biofix group, 10 from the AO group) operated two or more years ago were contacted to see if any complications had occured since they were last seen. In 4 cases a Biofix screw broke down just beneath the head during insertion. This did not result in an insufficient fixation of the fracture. There were no early post-operative complications. The functional and rontgenological results in both groups were equal. In three cases a sterile sinus developed at the site of screw insertion. Biofix rods and screws, made of polylactic acid, are a good alternative for the fixation of fractures of the ankle. The use of resorbable fracture fixation material has the advantage that a second operation to remove osteosynthesis material is not necessary. The long term results are good. There is, however, a possibility of development of tissue reaction to the resorbable material.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1433-2965
    Keywords: Key words:Armspan – Height – Osteoporosis – Vertebral deformities
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract: The prevalence of vertebral fractures in women increases with age but only about one third of these fractures are symptomatic. On the other hand, the presence of vertebral fractures is an independent risk factor for new osteoporotic fractures. In the present study we examined the hypothesis that differences between armspan and height are related to the presence of vertebral deformities in a cohort of 494 women aged between 55 and 84 years (mean age 67.6 years, SD 8.2 years) who were randomly selected from a large general practice in The Netherlands. Height and armspan were measured and vertebral morphometry of lateral radiographs of the spine was performed. Both height and armspan decreased significantly with age. The correlation between armspan and height was 0.83. Vertebral deformities were present in 32.7% of the women (grade I in 22.4% and grade II in 10.3%). Only the prevalence of grade II deformities rose with age. The variation of the difference between armspan and height in the groups with or without grade II vertebral deformities was comparable and relatively large (range 〉15 cm). The difference in mean values was small between those groups (1.6 cm) and could not differentiate between women with and without vertebral deformities. Our data show that the presence of vertebral deformities cannot be detected by the difference between armspan and height.
    Type of Medium: Electronic Resource
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