ABSTRACT
A fully automated, random access method for the determination of cannabinoids (UTHC) was developed for the Dimension AR and XL clinical chemistry systems. The method utilizes Abuscreen ONLINE reagents and a multianalyte liquid calibrator containing 11-nor-Delta(9)-THC-9-carboxylic acid. Within-run and total reproducibility, determined using NCCLS protocol EP5- T2, was less than 0.6% and 1.6% CV, respectively, at all concentrations. Calibration stability was retained for at least 30 days. An extensive evaluation of non-structurally related drugs and various physiological substances indicated lack of interference in the method. No sample carry-over was observed following a specimen containing 1886 ng/ml 11-nor-Delta(9)-THC-9-carboxylic acid. A 99.1% agreement (N = 445 samples) was found between an EMIT based method on the aca discrete clinical analyser and the Dimension UTHC method.Dimension clinical chemistry system and aca discrete clinical analyser are registered trademarks of Dade International.
ABSTRACT
A di-(carboxamidomethyl) derivative of molybdopterin, the organic component of the molybdenum cofactor, has been prepared under conditions favoring retention of all of the structural features of the molecule. The specific radioactivity of [1-14C]iodoacetamide incorporated relative to the amount of phosphate indicated two alkylation sites per pterin. Energy-dispersive x-ray analysis of the derivative showed the presence of 2 sulfurs in the derivative. An exact mass corresponding to the molecular formula C14H18N7O5S2 was obtained for the MH+ ion of the alkylated, dephosphorylated compound by fast atom bombardment mass spectroscopy. 1H NMR spectra of the phosphorylated and dephosphorylated forms of alkylated molybdopterin, in conjunction with the other data, have provided strong corroboration of the validity of the proposed structure of molybdopterin (Johnson, J. L., and Rajagopalan, K. V. (1982) Proc. Natl. Acad. Sci. U. S. A. 79, 6856-6860) as a 6-alkylpterin with a 4-carbon side chain containing an enedithiol on C-1' and C-2', a secondary alcohol on C-3', and a phosphorylated primary alcohol on C-4'. As isolated, the di-(carboxamido-methyl)molybdopterin was found to be a 5,6,7,8-tetrahydropterin.
Subject(s)
Coenzymes , Metalloproteins , Oxidoreductases Acting on Sulfur Group Donors/metabolism , Oxidoreductases/metabolism , Pteridines , Pterins , Xanthine Oxidase/metabolism , Animals , Cattle , Chemical Phenomena , Chemistry, Physical , Chickens , Magnetic Resonance Spectroscopy , Mass Spectrometry , Milk/enzymology , Molybdenum , Molybdenum CofactorsABSTRACT
Variations of the symbolic delayed-matching-to-sample procedure were used to study a pigeon's memory for a small number of pecks. In the first experiment a choice of a left or right sidekey after a delay or retention interval was reinforced if a bird had not pecked at all or had pecked exactly once, before the delay, respectively. In the second experiment a choice of a red or green sidekey, regardless of its position, was reinforced if a bird had not pecked at all or had pecked exactly twice, respectively. In the first experiment a bird could orient toward the correct choice during the delay, whereas it could not in the second experiment. In a third experiment a feature-probing method was used to study a pigeon's memory for a number of pecks in the context of certain other pecks. The results showed that a pigeon can remember a small number of pecks for one-half to one minute or more and that the percent correct is a decreasing function of the log retention interval. When a second number of pecks is different from the first number, memory for the first number lasts only a few seconds. When a second number is the same, memory lasts considerably longer. The more recent number of pecks is remembered better. The results are interpreted in terms of a theory which holds that a reinforcer, in general, may act on a subjects' memory for recent behavior to generate patterns of behavior.
