Interaction study between HCV NS5A-D2 and NS5B using 19F NMR

The non structural protein 5A (NS5A) regulates the replication of the hepatitis C viral RNA through a direct molecular interaction of its domain 2 (NS5A-D2) with the RNA dependent RNA polymerase NS5B. Because of conflicting data in the literature, we study here this molecular interaction using fluorinated versions of the NS5A-D2 protein derived from the JFH1 Hepatitis C Virus strain. Two methods to prepare fluorine-labelled NS5A-D2 involving the biosynthetic incorporation of a F-19-tryptophan using 5-fluoroindole and the posttranslational introduction of fluorine by chemical conjugation of 2-iodo-N-(trifluoromethyl)acetamide with the NS5A-D2 cysteine side chains are presented. The dissociation constants (K-D) between NS5A-D2 and NS5B obtained with these two methods are in good agreement, and yield values comparable to those derived previously from a surface plasmon resonance study. We compare benefits and limitations of both labeling methods to study the interaction between an intrinsically disordered protein and a large molecular target by F-19 NMR

Neuromonitoring and Emergency EEG

Intraoperative and Intensive Care Unit (ICU) EEG monitoring is very useful in cases of possible brain damage, for example, during carotid endarterectomy, cardiac surgery and neurosurgery, or when subclinical seizures are suspected. Continuous EEG (cEEG) monitoring during surgery is a valid and sensitive instrument for recognizing and/or preventing perioperative ischemic insults or any epileptiform activity responsible for convulsive or nonconvulsive symptoms. Furthermore, it allows brain functions monitoring for anesthetic drug administration, to determine the depth of anesthesia and for adjusting drug levels to achieve a predefined neural effect, such as burst suppression. In ICU, cEEG monitoring is essential to identify electrical discharges that occur frequently in critically ill patients and that are often clinically undetected, but potentially harmful if the diagnosis and the treatment are delayed. In the last years, cEEG monitoring has become a widespread practice, especially because of the use of new digital equipments, which are extremely compact and easy to use, not requiring a constant connection to the power grid and thus avoiding artifacts. EEG tracings can be visualized in real-time or analyzed after acquisition, either online or offline, with qualitative and/or quantitative methods. Finally, it is worth remembering that EEGs can be recorded bedside from a peripheral recording unit and then sent to the central unit, so that neurophysiologists can examine the recordings from distance and process them without interfering with the patients’ management