CRISPR-based oligo recombineering prioritizes apicomplexan cysteines for drug discovery.

Nucleophilic amino acids are important in covalent drug development yet underutilized as anti-microbial targets. Chemoproteomic technologies have been developed to mine chemically accessible residues via their intrinsic reactivity towards electrophilic probes but cannot discern which chemically reactive sites contribute to protein function and should therefore be prioritized for drug discovery. To address this, we have developed a CRISPR-based oligo recombineering (CORe) platform to support the rapid identification, functional prioritization and rational targeting of chemically reactive sites in haploid systems. Our approach couples protein sequence and function with biological fitness of live cells. Here we profile the electrophile sensitivity of proteinogenic cysteines in the eukaryotic pathogen Toxoplasma gondii and prioritize functional sites using CORe. Electrophile-sensitive cysteines decorating the ribosome were found to be critical for parasite growth, with target-based screening identifying a parasite-selective anti-malarial lead molecule and validating the apicomplexan translation machinery as a target for ongoing covalent ligand development.

[Effect of pre-mixed lidocaine with propofol on propofol injection pain in elderly patients].

The purpose of this study was to compare the younger and older patients in the incidence and the severity of the pain during injection of propofol. Thirty-four, elderly patients (60-80-yr-old) and 52 patients (20-40-yr-old) scheduled to undergo elective surgery were studied. We conducted a prospective, randomized and double-blinded trial. All patients were randomly allocated to one of two groups according to the agents added to 1% propofol 20 ml; Group S, normal saline 2 ml, and Group L, 2% lidocaine 2 ml. The pain on injection was rated as none, mild, moderate, or severe. Seventy percent of patients in the S group of elderly patients experienced pain, while 22% of patients experienced pain in the L group in elderly patients. The incidence of pain on injection in the S group of older patients was comparable with S group of younger patients. The severity of pain in elderly patients was significantly decreased after premixing with lidocaine. There were no significant differences between older and younger patients in the severity of propofol injection pain in both S group and L group. In conclusion, elderly patients suffered the pain on injection of propofol with the same incidence as the younger patients did. Lidocaine premixed with propofol significantly reduces the incidence and the severity of pain associated with propofol in elderly patients.