Identification of Synthetic Cannabinoid New Psychoactive Substances 4F-MDMB-BUTINACA and MDMB-4en-PINACA / 法医学杂志

Objective To establish a method that combines a series of techniques including Fourier transform infrared spectrum （FTIR）, gas chromatography-mass spectrometry （GC-MS）, high resolution mass spectrometry and nuclear magnetic resonance spectroscopy （NMR） for identification of unknown substances. Methods The unknown samples （off-white powder and yellow crystal） seized in the actual cases were detected by FTIR, GC-MS （methanol as solvent）, high resolution mass spectrometry （methanol as solvent） and NMR （deuterated methanol as solvent）. Results The mass spectrum characteristic ions m/z of the main components in the samples measured by GC-MS were 219 （base peak）, 363, 307, 304, 275, 145, 131 and 213 （base peak）, 357, 301, 298, 269, 185, 171, 145 and 131, respectively. The accurate mass numbers [M+H]+ measured by high resolution mass spectrometry were 364.203 61 and 358.212 34, respectively. The unknown samples were identified as synthetic cannabinoid new psychoactive substances 4F-MDMB-BUTINACA and MDMB-4en-PINACA after data consultation and database retrieval and comparison, combined with infrared analysis and mass spectrometry data analysis, and their structures were confirmed by 1H-NMR. Conclusion The established multi-technology joint identification method can be used to identify 4F-MDMB-BUTINACA and MDMB-4en-PINACA in unknown samples. This method is fast, convenient, accurate, reliable and practical, and can provide reference for the identification of cases involving such substances in the future.

The progresses of molecular mechanism of Isoniazid resistance in Mycobacterium Tuberculosis / 医学研究生学报

Mycobacterium tuberculosis is the causative agent of tuberculosis, which is a threat to public health worldwide. Isoniazid is one of the most active compounds used to treat tuberculosis worldwide. The pro-drug isoniazid is activated by catalase-peroxidase (KatG), and the active isoniazid products are targeted to InhA. The molecular mechanisms of isoniazid resistance involve several genes mutations. Mutation in the katG gene is the major cause for isoniazid resistance, followed by inhA, kasA, oxyR . Efflux pump systems also play important role in conferring isoniazid resistance. Understanding the mechanisms operating behind isoniazid action and resistance would enable better diagnosis and treatment of isoniazid-resistant tuberculosis.