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  • Uric acid  (2)
  • Aspergillus microcysticus  (1)
  • Asposterol  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Interaction of allopurinol and hydrochlorothiazide during prolonged oral administration of both drugs in normal subjects (1994)
    Springer
    Journal of molecular medicine 72 (1994), S. 1071-1075 
    Details
    ISSN: 1432-1440
    Keywords: Allopurinol ; Oxipurinol ; Hydrochlorothiazide ; Uric acid ; Drug interaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The interaction of allopurinol (300 mg/day) and hydrochlorothiazide (50 mg/day) was studied in seven healthy male volunteers during prolonged coadministration of the two drugs using defined dietary conditions. A formula diet was administered with the allopurinol throughout the 24-day study, while hydrochlorothiazide was added during days 11–21. After the addition of hydrochlorothiazide both plasma uric acid and plasma oxipurinol rose for 6 days – 24% and 30%, respectively, compared to steady-state levels during allopurinol alone (P 〈 0.01 each). In neither substance were variations in renal excretion significant. By the end of combined treatment (day 21), the changes induced by hydrochlorothiazide had already been reversed to a considerable extent. It is concluded that both in normal individuals and in patients with normal renal clearance of uric acid the effect of hydrochlorothiazide on the plasma concentration and renal excretion of oxipurinol is small. When taking both drugs, there is no increased risk during long-term treatment, and a risk is even questionable during the first days.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00577758
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  • 2
    Electronic Resource
    Electronic Resource
    A study of dose-response relationships of allpurinol in the presence of low or high purine turnover (1988)
    Springer
    Journal of molecular medicine 66 (1988), S. 153-159 
    Details
    ISSN: 1432-1440
    Keywords: Allopurinol ; Uric acid ; Oxypurines ; Orotic acid ; Dietary purines ; Overproduction ; Purine deficit
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Effects of allopurinol (125–500 mg/m2 body surface) were studied in normal subjects during periods of 18 days both during a purine-free, isoenergetic liquid formula diet and additional intake of ribonucleic acid, 4 g/day. Plasma uric acid and renal excretion of uric acid, oxypurines (hypoxanthine plus xanthine) and orotic acid were measured and total purine excretion calculated. Effects of allopurinol were evaluated by comparison of the results obtained in the steady state during diet alone (average of days 7–10) with those during allopurinol administration (days 16–18). During the purine-free diet, plasma uric acid was lowered more than urinary uric acid by allopurinol on doses of 250–500 mg/m2 (44%–54% of control values on 500 mg/m2), demonstrating an increase in renal clearance. At the same dose, the uric acid lowering effect of allopurinol was more pronounced with than without purine loads (plasma 41%, urine 32% of control on 500 mg/m2 during purine intake), while renal uric acid clearance was decreased. The more pronounced reduction of uric acid excretion during purine administration was balanced to the greater part by a more pronounced increased in oxypurine excretion. Total purine excretion was reduced by about 20% during the purine-free diet irrespective of dose. The size of this purine deficit was doubled, but was also independent of dose during addition of purines. Orotic acid excretion increased with dose during allopurinol treatment and was reduced by addition of purines. With respect to uric acid lowering effects, these results are in accordance with findings in patients overproducing uric acid endogenously and suggest that the uric acid lowering effect of allopurinol is enhanced with increasing concentrations of purine bases, presumably due to the tight binding of oxipurinol to xanthine oxidase. The small uricosuric effect of allopurinol seen during ingestion of the purine-free diet possibly is attributable to drug-induced orotic aciduria. The increase in size during purine intake of the purine deficit may result from reduced absorption of dietary purines during allopurinol treatment. Apparently, maximum effects of allopurinol on endogenous synthesis and/or absorption of purines from the gut are exerted by low doses.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01727784
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  • 3
    Electronic Resource
    Electronic Resource
    Stoffwechselprodukte von Mikroorganismen (1974)
    Springer
    Archives of microbiology 100 (1974), S. 73-95 
    Details
    ISSN: 1432-072X
    Keywords: Asposterol ; Aspergillus microcysticus ; Broad Spectrum Antibiotic ; Steroid Antibiotic ; Cytoplasmic Membrane ; Cytolysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Description / Table of Contents: Zusammenfassung Aspergillus microcysticus Sappa, Stamm TÜ 502, bildet ein bisher unbekanntes Antibioticum, das Asposterol genannt wird. Es läßt sich aus dem Filtrat von Submerskulturen des Pilzes mit Äthylacetat extrahieren und nach anschließender Säulenchromatographie an Kieselgel durch Elution mit Benzol/Äthylacetat in Ausbeuten bis zu 35 mg/l in praktisch reiner Form darstellen. Asposterol ist lipophil und instabil. Ihm kommt die Summenformel C24H33NO4, MG 399, zu. Die Verbindung liegt in zwei isomeren Formen vor und besitzt vermutlich ein Steran-Grundgerüst. Asposterol hemmt das Wachstum von Bakterien und Pilzen. Die minimale Hemmkonzentration liegt für Bacillus subtilis bei 0,3 μg/ml, für Schizosaccharomyces pombe bei 1,2 μg/ml. Die Hemmwirkung des Asposterols wird durch α-Tocopherol aufgehoben. Als primärer Wirkort des Antibioticums wird die Cytoplasma-Membran angesehen. Linolensäure, Undecen(10)säure und andere ungesättigte Fettsäuren ähneln dem Asposterol in der Art ihrer antimikrobiellen Wirkung.
    Notes: Abstract Aspergillus microcysticus Sappa TÜ 502 produces a formerly unknown antibiotic named asposterol. Extractions of culture filtrates from fermentations with ethyl acetate and subsequent column chromatography of the extracts on silica gel using benzene/ethyl acetate for the elution yielded up to 35 mg/l of practically pure preparations of the antibiotic. Asposterol is lipophilic and instable. The elemental composition was determined as C24H33NO4, molecular weight 399. The antibiotic exists in two isomeric forms. A steran skeleton is attributed to the compound. There is no evidence for other similarities with known steroid antibiotics. Asposterol inhibits both bacteria and fungi. The minimal inhibitory concentrations are 0.3 μg/ml for Bacillus subtilis and 1.2 μg/ml for Schizosaccharomyces pombe. The inhibitory effect of asposterol is compensated by α-tocopherol. It is assumed that the cytoplasmic membrane is the site of the primary antibiotic action. Linolenic acid, undecylenic acid and other unsaturated fatty acids show similarities with respect to the type of their antimicrobial effects.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00446308
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    Paper (German National Licenses)
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