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  • 1
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Smooth pursuit eye movements are evoked by retinal image motion of visible moving objects and can also be driven by the internal representation of a target due to extraretinal mechanisms (e.g. efference copy). To delineate the corresponding neuronal correlates, functional magnetic resonance imaging at 1.5 T was applied during smooth pursuit at 10 °/s with continuous target presentation and target blanking for 1 s to 16 right-handed healthy males. Eye movements were assessed during scanning sessions by infra-red reflection oculography. Smooth pursuit performance was optimal when the target was visible but decreased to a residual velocity of about 30% of the velocity observed during continuous target presentation. Random effects analysis of the imaging data yielded an activation pattern for smooth pursuit in the absence of a visual target (in contrast to continuous target presentation) which included a number of cortical areas in which extraretinal information is available such as the frontal eye field, the superior parietal lobe, the anterior and the posterior intraparietal sulcus and the premotor cortex, and also the supplementary and the presupplementary eye field, the supramarginal gyrus, the dorsolateral prefrontal cortex, cerebellar areas and the basal ganglia. We suggest that cortical mechanisms such as prediction, visuo-spatial attention and transformation, multimodal visuomotor control and working memory are of special importance for maintaining smooth pursuit eye movements in the absence of a visible target.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 59 (1989), S. 0 
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract Growth of Bacillus sp. DSM 2923 on nicotinic acid in mineral medium was dependent on the concentration of sodium molybdate added. Addition of increasing amounts of tungstate to the medium resulted in an inhibition of growth on nicotinic acid or 6-hydroxynicotinic acid as sole source of carbon and energy. Chlorate-resistant mutants were isolated which were not able to degrade nicotinic acid and 6-hydroxynicotinic acid nor to reduce nitrate. Additionally, enzyme activities of nicotinic acid dehydrogenase and 6-hydroxynicotinic acid dehydrogenase increased with increasing concentrations of molybdate (10−8 to 10−6 M) added to the medium, and decreased with increasing amounts of tungstate (10−6 to 10−5 M) in the medium.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract The molecular mass of the molybdenum cofactor was determined to be 700 to 780 for four eubacterial dehydrogenases which are involved in the hydroxylation of nicotine, nicotinate, 2-furancarboxylate and xanthine by Arthrobacter oxidans, Bacillus niacini and Pseudomonas putida. This strengthens support for the finding that the bacterial molybdenum cofactor differs from that of eukaryotes.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract Bactopterin was resolved in the eubacterial molybdoenzymes nicotinic acid dehydrogenase from Bacillus niacini, nitrite oxidoreductase from Nitrobacter hamburgensis and respiratory nitrate reductase from Pseudomonas stutzeri. These findings lend support to the proposal that bactopterin is a common cofactor of eubacterial molybdoenzymes.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-072X
    Keywords: 2-Hydroxyquinoline ; Molybdenum-binding pterin ; Quinoline ; Quinoline dehydrogenase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Eighteen different aerobic bacteria were isolated which utilized quinoline as sole source of carbon, nitrogen, and energy. Attempts were unsuccessful at isolating anaerobic quinoline-degrading bacteria. The optimal concentration of quinoline for growth was in the range of 2.5 to 5 mM. Some organisms excreted 2-hydroxyquinoline as the first intermediate. Hydroxylation of quinoline was catalyzed by a dehydrogenase which was induced in the presence of quinoline or 2-hydroxyquinoline. Quinoline dehydrogenase activity was dependent on the availability of molybdate in the growth medium. Growth on quinoline was inhibited by tungstate, an antagonist of molybdate. Partially purified quinoline dehydrogenase from Pseudomonas putida Chin IK indicated the presence of flavin, iron-sulfur centers, and molybdenum-binding pterin. M r of quinoline dehydrogenase was about 300 kDa in all isolates investigated.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-072X
    Keywords: Bacillus niacini ; Bactopterin ; 6-Hydroxynicotinate dehydrogenase ; Molybdenum ; Nicotinate dehydrogenase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The enzymes nicotinate dehydrogenase and 6-hydroxynicotinate dehydrogenase from Bacillus niacini could be purified to homogeneity by means of anion exchange chromatography, hydrophobic interaction chromatography, gel filtration, and chromatography on hydroxylapatite. During enrichment procedures both enzymes showed a significant loss in specific activity. The molecular weight of nicotinate dehydrogenase and 6-hydroxynicotinate dehydrogenase was determined to be about 300,000 and 120,000, respectively. They were highly substrate specific and transferred electrons only to artificial acceptors of high redox potential. The K m for their specific substrates was about 1.0 mM for both enzymes, and their pH optimum was determined to be 7.5. For nicotinate dehydrogenase a content of 8.3 mol iron, 1.5 mol acid-labile sulfur, 2.0 mol flavin, and 1.5 mol molybdenum per mol of enzyme was determined. Both enzymes contained FAD and Fe/S center. After inhibition by KCN, thiocyanate was detected, and subsequently the initial nicotinate dehydrogenase activity was restored by the addition of Na2S indicating the presence of cyanolyzable sulfur. 6-Hydroxynicotinate dehydrogenase seemed to contain the same type of constituents as determined for nicotinate dehydrogenase. A partial immunological identity of the enzymes could be shown by antibodies raised against nicotinate dehydrogenase.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1439-099X
    Keywords: Schlüsselwörter: Endometriumkarzinom ; Strahlentherapie ; HDR-Afterloading ; Key Words: Endometrial cancer ; Adjuvant radiotherapy ; Brachytherapy ; High-dose-rate afterloading
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Purpose: This retrospective study was designed to evaluate the role of adjuvant radiotherapy for surgically treated endometrial carcinoma. Patients and Methods: From 1980 through 1988, 541 patients were treated with either intravaginal cuff irradiation with a high-dose-rate (HDR) Iridium-192 remote afterloading technique (n = 294) or with combined HDR-brachytherapy and additional external pelvic irradiation to 54 Gy (n = 247) after surgery for endometrial cancer. Afterloading irradiation was administered in 4 fractions 4 to 6 weeks after surgery. A dose of 30 Gy was delivered at a depth of 0,5 cm from the vaginal mucosa. Results: Patients with HDR-brachytherapy alone showed a 5-year survival of 94.3% for Stage I and 73.6% for Stage II (p = 0.0007). Patients who received both brachytherapy and additional external pelvic irradiation had a 5-year survival of 94.1% for Stage I, 81.1% for Stage II, 70.4% for Stage III and 46.9% for Stage IV (p = 0.0001). The main predictors for survival in a multivariate analysis were stage and grading. Patients with combined radiotherapy had a local recurrence rate of 3.2%, whereas patients with brachytherapy alone who were better selected and had more favorable prognostic factors showed a recurrence rate of 2%. Low-risk patients (Stage I, Grade 1, low infiltration) in the HDR-brachytherapy group had 6 relapses, mainly caused by insufficient treatment on the basis of papillary histology. High-risk patients with poorly differentiated tumors, which infiltrate more than half the myometrial wall might benefit from additional external radiotherapy in terms of reduction of local recurrence and better survival. Fife-year actuarial survival rate was 93.6% after combined radiotherapy vs 86.7% after brachytherapy alone. Complications were graded according to the RTOG scoring system. Severe late complications were fistulas of bladder and/or bowel, which orrurred in 2.8% in the comnbined radiotherapy group, and 0.7% in the HDR brachytherapy group. Conclusions: Low-risk patients should be generally treated postoperative with HDR-brachytherapy alone. Combined radiotherapy decreased pelvic relapses for high-risk patients with overall low complication rates. We conclude that an individually adjusted postoperative radiotherapy allows a well tolerated treatment with excellent results.
    Notes: Ziel: Im Rahmen der Diskussion um die Wertigkeit der postoperativen Strahlentherapie bei Patientinnen mit einem Endometriumkarzinom haben wir das Patientengut der Klinik und Poliklinik für Strahlentherapie der Martin-Luther-Universität Halle-Wittenberg analysiert. Patienten und Methode: In diese retrospektive Analyse wurden die Daten von 541 zwischen 1980 und 1988 postoperativ bestrahlten Patientinnen aufgenommen. Die Auswertung der Daten erfolgte getrennt nach Therapiemodi, entweder einer alleinigen intravaginalen Strahlentherapie (HDR-AL) mit Iridium-192 oder aber einer Kombination von HDR-AL und zusätzlicher perkutaner Bestrahlung. Ergebnisse: Im Stadium I betrug die Fünf-Jahres-Überlebensrate nach HDR-AL 94,3%, im Stadium II 73,6% (p=0,0007). Ebenfalls signifikant war die Abhängigkeit der Fünf-Jahres-Überlebensrate vom Grading: Sie betrug 94,1% bei G1-, 91,9% bei G2- und 78,9% bei G3-Formen (p=0,0007). Nach kombinierter Strahlentherapie betrug die Fünf-Jahres-Überlebensrate im Stadium I 91,8%, Stadium II 81,1%, Stadium III 70,4% sowie im Stadium IV 46,9% (p=0,0001). Durch eine multivariate Analyse der Daten wurde die Abhängigkeit der Überlebensraten vom Stadium und Differenzierungsgrad gefunden. Lokalrezidive traten bei 2% der Patientinnen nach HDR-AL und bei 3,2% nach kombinierter Strahlentherapie auf. Ein wichtiger Einflußfaktor auf das Auftreten von lokoregionären Rezidiven war die Infiltrationstiefe. Low-risk-Patientinnen, die zusätzlich perkutan bestrahlt worden waren, hatten mit 93,3% eine ebenso gute Überlebenswahrscheinlichkeit wie Patientinnen mit alleinigem HDR-A: (94,8%), wobei in dieser Gruppe sechs Rezidive auftraten. Die Risikofaktoren Diabetes Mellitus, Hypertonie und/oder Adipositas bestanden bei 31,6% aller Patientinnen. Die Rate an schweren chronischen Nebenwirkungen betrug 2,8% bei allen kombiniert strahlentherapeutisch behandelten Patientinnen. Nach alleinigem HDR-AL wurden bei zwei diabetisichen Patientinnen (0,7%) Rektum-Scheiden-Fisteln beobachtet. Schlußfolgerung: Mit dem Einsatz der individuellen postoperativen Strahlentherapie bei möglichst exaktem Staging steht ein relativ nebenwirkungsarmes Behandlungskonzept mit ausgezeichneten Therapieergebnissen zur Verfügung. Der Verzicht auf eine postoperative Strahlentherapie ist nach unserer Auffassung derzeit nicht angebracht und sollte sehr sorgfältig begründet werden.
    Type of Medium: Electronic Resource
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