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  • 1
    ISSN: 1432-1017
    Schlagwort(e): Key words Carbonmonoxy-Myoglobin ; Recombination kinetics ; Mössbauer spectroscopy ; Scaling law ; Activated tunneling
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Physik
    Notizen: Abstract We have studied the recombination kinetics of carboxymyoglobin (after photodissociation of the CO ligand) by Mössbauer spectroscopy for temperatures in the range 4.2 – 60 K. The observed kinetics display non-exponential behaviour which was monitored over periods of a few days. It is shown that the time dependence of the kinetics can be reduced to a single universal function of the temperature-dependent variable (t/τ 1/2(T)) β(T) . The half-decay time τ 1/2(T) and the scaling parameter β(T) are analysed for the presence of tunneling effects. The non-Arrhenius temperature dependence of the half-decay time below 60 K is interpreted as activated tunneling in models with an Eckart barrier or a fluctuating barrier.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Springer
    European journal of orthopaedic surgery & traumatology 7 (1997), S. 195-198 
    ISSN: 1432-1068
    Schlagwort(e): Fractures of the head of the tibia ; Osteitis ; Infection ; Surgical flaps ; Fracture de l'extrémité proximale du tibia ; Ostéite ; Infection ; Lambeaux locaux
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Beschreibung / Inhaltsverzeichnis: Résumé Nous avons examiné au total 52 patients présentant avec infection après fracture de l' extrémité proximale du tibia entre 1988 et 1992. 26 patients étaient transférés d'autres hôpitaux avec une ostéite évolutive, 26 patients étaient traités entièrement dans notre hôpital. Nous discutons l'étiologie de l'infection de ces deux groupes. Tous les patients ont été traités avec débridement radical. Une stabilisation osseuse fut nécessaire dans 73 % de cas. Nous avons réalisé une résection segmentaire à cause d'une large infection dans 3 cas. La perte de substance causée par cette intervention a été fermée par une lambeau local dans 11 cas. Ainsi nous avons pu arrêter l'infection dans 41 cas mais seulement 7 patients peuvent être considérés comme entièrement guéris (13 %). Dans 9 cas l'amputation a due être effectuée. Malgré le succès thérapeutique concernant l'infection elle même, le résultat fonctionnel est resté mauvais. C'est pourquoi éviter l'infection reste le point le plus important traitement d'une fracture. Le pourcentage des infections peut être abaissé en utilisant un type d'osteosynthèse adapté aux besoins des tissus mous. Il faut fermer les pertes de substance initiales d'une fracture ouverte ou causées par le traitement initial par un lambeau de muscle jumeau (musculus gastrocnemius) après un délai de quelques jours. Soigner les tissus mous correctement est au moins aussi important que de reconstruire les fragments osseux, lorsque l'on traite une fracture de l'extrémité proximale du tibia.
    Notizen: Summary A total of 52 patients with infection after fracture of the proximal tibia were retrospectively reviewed from 1988 to 1995. 26 patients were transfered from peripheral hospitals with active osteitis, while 26 patients had been primarily treated in our hospital. Refering to the total group of patients, infection inducing factors are discussed critically. All patients underwent radical debridement. Restoration of bone stability had to be done in 73 %. Due to the extent of infection, segmental resection had to be perfomed on 3 patients. Resulting soft tissue defects were closed with local flaps in 11 cases. Infection was controlled in 41 patients, but only 7 could be classified as “cured”. Nine patients had amputations after failure of treatment. Despite successful therapy, the functional results are poor. Therefore, avoiding infection, has top priority in post fracture treatment. The correct form of osteosynthesis adapted to the soft tissue lesion can lower infection rates significantly. Soft tissue defects, resulting from open fractures or after primary treatment, have to be closed by gastrocnemius flap transfer within a short time. The management of the soft tissue is at least as important as the reconstruction of the bone in the treatment of fractures of the head of the tibia.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    ISSN: 1432-1076
    Schlagwort(e): Key words Glucosephosphate isomerase ; haemolytic anaemia ; enzyme mutants
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Biochemical and molecular genetic studies were performed on the enzyme variants of two patients compound heterozygous for glucose phosphate isomerase (GPI) deficiency, both suffering from severe haemolytic anaemia. The enzymes of case 1 (GPI `Zwickau') and case 2 (GPI `Nordhorn' [25]), revealed reduced GPI activity and remarkable thermolability. Glucose-6-phosphate (Gluc-6-P) concentration was elevated 2.3 times in case 1 and 3.8 times in case 2. Sequencing the patients' GPI genes showed four different point mutations, two of them involving highly conserved amino acids. The c1039 C→T substitution, found in the gene of GPI `Zwickau', has been described recently [30] and causes an Arg 347→Cys substitution close to the putative catalytic site. The second mutation in this case is a novel c1538 G→A substitution causing a Trp→stop mutation at position 513 apparently resulting in premature RNA degradation thus resulting either in a complete lack of protein or a protein which does not show GPI activity. In the gene of GPI `Nordhorn' a c1028 A→G mutation was discovered, also previously described [1, 9] causing a Gln 343→Trp substitution. The second mutation was a novel splice site mutation at the border of intron 15 to exon 16: IVS15-(-2) A→C which leads to an aberrant splicing of exon 16, thus resulting either in a truncated and most likely inactive enzyme or in no protein at all. Conclusion Biochemical and molecular genetic studies performed with the enzyme variants GPI `Zwickau' and GPI `Nordhorn' showed that in both cases the simultaneous occurrence of a single amino acid sub‐stitution affecting the active site, together with a nonsense mutation leading to the loss of major parts of the enzyme probably explains the severe clinical course of the disease.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Neurochemical research 22 (1997), S. 921-932 
    ISSN: 1573-6903
    Schlagwort(e): Dense core vesicles ; synaptic vesicles ; membrane protein ; adrenergic terminals
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The membrane proteins of adrenergic large dense core vesicles, in particular those of chromaffin granules, have been characterized in detail. With the exception of the nucleotide carrier all major peptides have been cloned. There has been a controversy whether these vesicles contain antigens like synaptophysin, synaptotagmin and VAMP or synaptobrevin found in high concentration in synaptic vesicles. One can now conclude that large dense core vesicles also contain these peptides although in lower concentrations. The biosynthesis of large dense core vesicles is analogous to that of other peptide secreting vesicles of the regulated pathway. One cannot yet definitely define the biosynthesis of small dense core vesicles which apparently have a very similar membrane composition to that of large dense core vesicles. They may form directly from large dense core vesicles when their membranes have been retrieved after exocytosis. These membranes may become sorted in an endosomal compartment where peptides may be deleted or added. Such an addition could be derived from synaptophysin-rich vesicles present in adrenergic axons. However small dense core vesicle peptides may also be transported axonally independent of large dense core vesicles. For proving one of these possibilities some crucial experiments have been suggested.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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