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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of pineal research 5 (1988), S. 0 
    ISSN: 1600-079X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Melatonin is metabolised by hydroxylation at the 6 position and to a variable extent by demethylation. Both metabolites so formed are excreted as sulphate and, to a lesser extent, glucuronide conjugates. To authenticate these metabolites which we had earlier isolated from urine, we wished to have synthetic samples. Since we also required them as standards we needed them as powders. A review of the literature showed that there were only two published methods, of which only one gave rise to 6-sulphatoxy-melatonin (SaMT) as a solid.The other metabolite, N-acetyl-serotonin-sulphate (SNAS), has not been previously made, and we here describe some of its chemical properties. Our method modifies a published method taking into account the results given in a recent paper describing the sulphation of the thyroid hormones, T3 and T4. Hydroxy-melatonin is thus reacted with a complex formed from dimethylformamide and chlorosulphonic acid. The reaction is of interest since it is rapid, easy, and produces pure powdered material in excellent yield.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1435-1463
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary 1. Acetylmethoxytryptophol, originally isolated from the pineal gland, inhibits both the nicotinic and muscarinic receptor stimulatory activities of acetylcholine on frog rectus muscle and guinea pig ileum. 2. Synthetic homologues and analogues, including the acetyl-, propionyl-, butyryl-, and valeryl-methoxytryptophols, tryptophols andα-methyltryptophols have been prepared and shown to possess similar activity on the frog muscle, with butyryl compounds being the most active. Methoxytryptophol, tryptophol,α-methyltryptophol and acetylhydroxytryptophol possess little or no activity. 3. All acyltryptophols tested inhibit the effect of increased potassium concentrations on frog muscle. 4. It is concluded that the acyltryptophols act not at the transmitter receptor level but either at the potassium ion channel or elsewhere in the cell membrane.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1612-1112
    Keywords: Gas chromatography-IR spectroscopy ; Propanediol ; Acyclovir
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A simple procedure is described for the determination of the 1,2-propanediol (propylene glycol) content of cream formulations containing the antiviral drug Acyclovir. Analysis of a solvent extract by gas chromatography coupled to an infra-red spectrometer enables the target analyte to be positively identified and an estimate of its concentration to be made. This application utilises the newer Tracer cryogenic deposition interface for gas chromatography and infra-red spectroscopy. This offers an alternative and complementary analytical strategy to gas chromatography coupled to mass spectrometry.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 20 (1991), S. 759-762 
    ISSN: 1052-9306
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Citrulline is formed as a co-product in the biosynthesis of nitric oxide from L-arginine by the action of either constitutive or inducible nitric oxide synthase which is present in a variety of cells. We have previously shown that the oxygen atom incorporated into both nitric oxide and citrulline derives from molecular oxygen and not water. This paper describes the tandem mass spectrometric analysis of citrulline synthesized by the macrophage cell line J774 in the presence of native or guanidino-labelled arginine and air or isotopically enriched oxygen. The results confirm that oxygen is incorporated into the ureido position of citrulline.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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