False Decrease in Uric Acid Caused by IgM Paraprotein.

BACKGROUND: To explore the reason and treating method for the negative value of uric acid in a patient patient. METHODS: The serum of a patient with a negative uric acid detection value was diluted 5 times with "sterilized water" and with "normal saline". Additionally, the serum was treated with PEG6000 protein, and uric acid was detected. RESULTS: Elevated IgM paraprotein in the patient resulted in abnormal uric acid response curves in serum samples or diluted serum samples. After the serum was precipitated with PEG600, the uric acid response curve was basically normal. CONCLUSIONS: The negative value of the patient's uric acid test was caused by the IgM paraprotein. After removing the interference by PEG6000 protein a true and accurate uric acid result was obtained.

Exothermic or Endothermic Decomposition of Disubstituted Tetrazoles Tuned by Substitution Fashion and Substituents.

Nitrogen-rich compounds such as tetrazoles are widely used as candidates in gas-generating agents. However, the details of the differentiation of the two isomers of disubstituted tetrazoles are rarely studied, which is very important information for designing advanced materials based on tetrazoles. In this article, pairs of 2,5- and 1,5-disubstituted tetrazoles were carefully designed and prepared for study on their thermal decomposition behavior. Also, the substitution fashion of 2,5- and 1,5- and the substituents at C-5 position were found to affect the endothermic or exothermic properties. This is for the first time to the best of our knowledge that the thermal decomposition properties of different tetrazoles could be tuned by substitution ways and substitute groups, which could be used as a useful platform to design advanced materials for temperature-dependent rockets. The aza-Claisen rearrangement was proposed to understand the endothermic decomposition behavior.