Ana Laboratoire

Intrinsically disordered proteins/peptides play a crucial role in many physiological and pathological events and may assume a precise conformation upon binding to a specific target. Recently, we have described the conformational and functional properties of two linear ester peptides provided with the following sequences: Y-G-E-C-P-C-K-OAllyl (PepK) and Y-G-E-C-P-C-E-OAllyl (PepE). Both peptides are characterized by the presence of the "CPC" motif together with a few amino acids able to promote disorder. The CPC sequence is a binding motif for the CXCR4 receptor that represents a well-known target for cancer therapies. In this paper, we report on synthetic amphiphilic peptides that consist of lipophilic derivatives of PepE and PepK bearing two stearic alkyl chains and/or an ethoxylic spacer. These peptide amphiphiles form stable supramolecular aggregates; they present conformational features that are typical of intrinsically disordered molecules as shown by CD spectroscopy. Solution fluorescence and DLS studies have been performed to evaluate Critical Micellar Concentrations and the dimension of supramolecular aggregates. Moreover, preliminary in vitro cell-based assays have been conducted to investigate the molecular recognition processes involving the CXCR4 receptor. In the end, the results obtained have been compared with the previous data generated by the corresponding non-amphiphilic peptides (PepE and PepK).

The effects of MRI acoustic noise on anaesthesia safety concerns have not yet been documented. The objectives of this study were to provide subjective and objective evaluations of anaesthesia alarm audibility during MRI and to review the literature to determine whether or not to worry about our results. Following Institutional Review Board's approval, we tested the audibility of four anaesthesia equipment alarms and selected one of them. Additionally, we selected the least audible of three MRI sequences (spin echo) for the study. The evaluations were conducted inside and outside the scanning room in a subjective and objective manner. First, 20 normal hearing consenting adult volunteers rated their audibility of the anaesthesia alarm using a 10-point numerical scale (0 = not audible to 10 = maximum audibility). Second, a sound level meter was used to measure the intensity of acoustic noise (A-weighted scale) under the above-mentioned conditions. Data, expressed as median [interquartile range], were analysed using the Wilcoxon test with P less than 0.05 considered as significant. The subjective audibility scores (inside vs. outside the MRI room) were 9.0 [8.5-10.0] vs. 7 [6.5-8.0]. During MRI scanning, the scores were 6.0 [5.5-7.0] vs. 4.0 [3.5-5.0], respectively (P < 0.001). The sound level measurements were 70 [69-71] vs. 55 [54-57] dB (A). During MRI 91 [91-92] dB (A) vs. 68 [65-69] dB (A) (P < 0.001). The audibility of the anaesthesia alarm is significantly reduced during MRI, particularly outside the scanning room. Consequently, optical alarms and interactive screens (outside the room) must be available without exception.