PubMed · 6065995
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1967-12-02. Allantoin.. https://pubmed.ncbi.nlm.nih.gov/6065995/
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In this study we have shown that a range of compounds that are structurally similar to alloxan are able to protect mice against the diabetogenic effect of alloxan. The compounds include a group of five barbiturates, a group of five hydantoins, the methylxanthines caffeine and theophylline, the related compound uric acid, and ethosuximide. They were injected intraperitoneally prior to intravenous injection of alloxan, and blood glucose concentration was used as an index of alloxan toxicity. The salient structural feature possessed by all of these protective compounds is a pair of carbonyl oxygen atoms separated by a distance of 4.5 A and projecting from an approximately planar heterocyclic five- or six-membered ring; in all cases the carbonyl groups are separated by a ring nitrogen. We suggest that this feature is required for the protective effect of these compounds. In order to test further the requirement for two ring carbonyl groups, we also examined the effects of two compounds containing hydroxyl groups projecting from a six-membered ring, inositol and glucuronic acid. In agreement with previous studies on hexoses, we found that the effects of compounds such as these are unpredictable, with inositol protecting against alloxan toxicity but glucuronic acid not. We are unable to identify the critical difference in structure between these two compounds.
A simple procedure is described for the assay of liver uric acid and allantoin and their specific radioactivity after administration of a radioactive precursor. Uric acid was quantified by the uricase reaction in liver trichloroacetic acid (TCA) extracts. The 'true' allantoin content of the liver could be estimated only after precipitation with Hg-acetate, a step by which the standard allantoin was also quantitatively recovered. Crude extracts lead to the evaluation of 'apparent' allantoin. For the determination of specific radioactivity, the Hg-acetate precipitate was further purified by ion-exchange chromatography. The purity of the two metabolites was confirmed by ultraviolet absorbance spectra, HPLC, constancy of specific radioactivity and the absence of amino acids. The incorporation of [14C]formate into uric acid and allantoin in the liver was studied by this procedure. The radioactivity in allantoin was several-fold higher than that in uric acid up to 60 min after administration of the precursor. This quite unexpected result is not easily explained on the basis of current knowledge.
AIMS: Testing the effectiveness of a topical combination preparation containing standardized leech extract, polidocanol and allantoin. STUDY DESIGN: Placebo-controlled, double-blind study in 80 patients with first and second degree hemorrhoids; duration of treatment one week; examinations performed on admission and on days 3, 4, 5 and 8. RESULTS: Both the subjective and objective symptoms and signs improved during the one week of treatment statistically significantly more rapidly under the test preparation as compared with placebo. Histologically demonstrable signs of inflammation were more clearly improved in the preparation group than in the placebo group. No side effects were observed. CONCLUSIONS: The good efficacy and tolerability of a topical therapeutic preparation in first and second degree hemorrhoids have been convincingly demonstrated.