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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 672 (1992), S. 0 
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1433-0474
    Keywords: Schlüsselwörter Herzerkrankung ; Thoraxschmerz ; Psychosomatische Störung ; Key words Heart disease ; Chest pain ; Psychosomatic disorder
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary Aims: Chest pain in children is often suspected to originate from cardiac disease. Aim of this study was to characterise the symptomatology of supposed cardiac chest pain in children and to investigate whether cardiac disease indeed underlies the pain or not. Furthermore, indications for a psychosomatic origin of the pain were searched for. Methods: The study involved 456 children referred to a pediatric cardiology outpatient department for chest pain. The patients were evaluated by ECG and echocardiogram. In selected cases, a chest radiograph, exercise ECG, or a 24-hour ECG monitoring was performed. A subgroup of 52 children and parents was interviewed on the basis of a questionnaire to evaluate the symptomatology of the pain, the family history, and psychosocial factors. Results: 15% of the children had diverse structural anomalies or arrhythmias usually of a low grade. The frequency of these findings did not differ from that of a control group without chest pain. Independent of the presence of these findings cardiac function was normal during exercise. The characteristic symptomatology (short, sharp, no radiation) did not correspond to that of ischemic heart disease, and was largely identical in children with and without cardiac findings. Factors typical of psychosomatic disorders were observed: a positive family history of „functional cardiac complaints” and other psychosomatic disorders particularly with regard to the mother, other somatic complaints prior to or along with the chest pain, and the presence of stressful life events. Conclusions: These data suggest that the described chest pain in children is a psychosomatic condition rather than caused by organic cardiac disease.
    Notes: Zusammenfassung Fragestellung: Thoraxschmerzen bei Kindern werden häufig mit Erkrankungen des Herzens in Zusammenhang gebracht. Im Rahmen dieser Studie sollten der Symptomkomplex kindlicher „Herzschmerzen” charakterisiert und seine Genese aus kardiologischer Sicht untersucht werden. Ein weiteres Ziel bestand darin, Hinweise auf psychogene Faktoren in der Schmerzgenese zu erhalten. Methode: In die Studie waren 456 Kinder einbezogen, die unter dem Verdacht von „Herzschmerzen” an kinderkardiologische Ambulanzen überwiesen worden waren. Die Basisdiagnostik umfaßte EKG und Echokardiographie. In vielen Fällen erfolgten zusätzlich Langzeit-EKG, Thoraxröntgen oder Belastungs-EKG. Zur Beschreibung der Symptomatik und zur Evaluierung familiärer und psychosozialer Faktoren wurde ein Fragebogen ausgearbeitet und damit eine Untergruppe von 52 Kindern untersucht. Ergebnisse: Bei 15% der Kinder wurden verschiedenartige und meist geringfügige strukturelle und funktionelle Abweichungen vom Normalbefund des Herzens beobachtet. Ihre Prävalenz war nicht höher als in einer Kontrollpopulation. Unabhängig vom Vorhandensein dieser Befunde war die kardiale Leistungsfähigkeit normal. Die typische Symptomatik (kurz, stechend, ohne Ausstrahlung) entsprach nicht der des ischämischen Herzschmerzes und war bei Kindern mit und ohne kardiale Veränderungen weitgehend identisch. Es wurden Faktoren beobachtet, die typisch für psychosomatische Erkrankungen sind: eine positive Familienanamnese für „funktionelle Herzbeschwerden” und andere psychosomatische Erkrankungen insbesondere hinsichtlich der Mutter, das gleichzeitige oder zeitlich versetzte Auftreten anderer Schmerzsyndrome und potentielle psychosoziale Belastungen. Schlußfolgerungen: Vermutlich spielen nicht manifeste organische Veränderungen am Herzen, sondern psychosomatische Faktoren in der Pathogenese des hier charakterisierten kindlichen Thoraxschmerzes eine Rolle.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract In an optimized sorbitol/yeast extract/mineral salt medium up to 12 U/l CMP-N-acetyl-neuraminic-acid (Neu5Ac) synthetase was produced by Escherichia coli K-235 in shake-flask culture. A colony mutant of this strain, E. coli K-235/CS1, was isolated with improved enzyme formation: in shake flasks with a yield of up to 20.8 U/l and 54 mU/mg protein in the cell extract. With this strain 26500 U CMP-Neu5Ac synthetase was produced with a high specific activity (0.128 U/mg) by fed-batch fermentation on 230-1 scale. On a 10-l scale the enzyme yield was 191 U/l culture medium. The enzyme was partially purified by precipitation with polyethyleneglycol resulting in a three- to fourfold enrichment and a recovery rate of more than 80%; most of the CTP hydrolysing enzymes were removed. The native synthetase was deactivated completely by incubation at 45°C for 10 min, but could be stabilized remarkably by glycerol and different salts. The enzyme was used for the preparative synthesis of CMP-Neu5Ac with a conversion yield of 87% based on CTP.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract  In an optimized sorbitol/yeast extract/mineral salt medium up to 12 U/l CMP-N-acetylneuraminic-acid (Neu5Ac) synthetase was produced by Escherichia coli K-235 in shake-flask culture. A colony mutant of this strain, E. coli K-235/CS1, was isolated with improved enzyme formation: in shake flasks with a yield of up to 20.8 U/l and 54 mU/mg protein in the cell extract. With this strain 26500 U CMP-Neu5Ac synthetase was produced with a high specific activity (0.128 U/mg) by fed-batch fermentation on 230-l scale. On a 10-l scale the enzyme yield was 191 U/l culture medium. The enzyme was partially purified by precipitation with polyethyleneglycol resulting in a three- to fourfold enrichment and a recovery rate of more than 80%; most of the CTP hydrolysing enzymes were removed. The native synthetase was deactivated completely by incubation at 45 °C for 10 min, but could be stabilized remarkably by glycerol and different salts. The enzyme was used for the preparative synthesis of CMP-Neu5Ac with a conversion yield of 87% based on CTP.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Bioprocess engineering 14 (1996), S. 291-297 
    ISSN: 0178-515X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract  The L-tert-leucine synthesis was performed continuously in series of two enzyme-membrane reactors by reductive amination of trimethylpyruvate with leucine dehydrogenase. The necessary “native” cofactor NADH is regenerated with the aid of a second enzyme, formate dehydrogenase. Considering detailed kinetic studies of initial reaction rates under conditions relevant to the process a kinetic model was developed. The model shows that the overall reaction rate is strongly inhibited by the reaction product. The reactor’s models combine the mass balances and proposed kinetic equations. The model adequacy was verified by using it to simulate the experiments and by comparing experimental and computed conversion, space-time yield and enzyme consumption. The calculations for the three reactor’s types (batch, single CSTR and a cascade of two CSTRs in series) were compared. The results showed that a single CSTR is no favourable reactor configuration due to the very strong product inhibition. Space-time yield drops from 560 g litre-1 day-1 in a batch reactor to 110 g litre-1 day-1 in a single CSTR at the highest conversion of 98%. At the conversion of 95% the difference in biocatalyst costs between batch and two CSTR in series is negligible. Therefore the use of two enzyme membrane reactors in series was proposed. The modelling in this work shows that the optimisation of the quantity of the enzyme used results in a minimisation of the biocatalyst costs.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Bioprocess and biosystems engineering 14 (1996), S. 291-297 
    ISSN: 1432-0797
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The L-tert-leucine synthesis was performed continuously in series of two enzyme-membrane reactors by reductive amination of trimethylpyruvate with leucine dehydrogenase. The necessary “native” cofactor NADH is regenerated with the aid of a second enzyme, formate dehydrogenase. Considering detailed kinetic studies of initial reaction rates under conditions relevant to the process a kinetic model was developed. The model shows that the overall reaction rate is strongly inhibited by the reaction product. The reactor's models combine the mass balances and proposed kinetic equations. The model adequacy was verified by using it to simulate the experiments and by comparing experimental and computed conversion, space-time yield and enzyme consumption. The calculations for the three reactor's types (batch, single CSTR and a cascade of two CSTRs in series) were compared. The results showed that a single CSTR is no favourable reactor configuration due to the very strong product inhibition. Space-time yield drops from 560 g litre−1 day−1 in a batch reactor to 110 g litre−1 day−1 in a single CSTR at the highest conversion of 98%. At the conversion of 95% the difference in biocatalyst costs between batch and two CSTR in series is negligible. Therefore the use of two enzyme membrane reactors in series was proposed. The modelling in this work shows that the optimisation of the quantity of the enzyme used results in a minimisation of the biocatalyst costs.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 55 (1997), S. 283-288 
    ISSN: 0006-3592
    Keywords: chloroperoxidase ; Caldariomyces fumago ; indole ; total turnover number ; space-time yield ; membrane reactor ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Chloroperoxidase from Caldariomyces fumago was applied for the oxidation of indole to oxindole using hydrogen peroxide as the oxidant in aqueous t-butyl alcohol medium. Different ways of adding the oxidant, various reactor types, and the use of a hydrogen peroxide-stat were compared, resulting in a 20-fold increase of the total turnover number (ttn) and space-time yield (sty). The highest ttn of 〉860,000 was obtained in a fed-batch reactor, whereas the highest sty of 120 g/(L · d) was reached in a continuously operated enzyme membrane reactor. The results were compared to other enzyme systems already established for the synthesis of amino acids and carbohydrates. © 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 55: 283-288, 1997.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Chemie Ingenieur Technik - CIT 69 (1997), S. 1306-1307 
    ISSN: 0009-286X
    Keywords: Chemistry ; Industrial Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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