Bispectral Index profile during carotid cross clamping

This study aimed at investigating the Bispectral Index (BIS) profile during carotid cross clamping (CXC). The study involved a pilot group of 10 patients undergoing routine carotid endarterectomy with shunt insertion under total intravenous anesthesia, and a study group of 26 additional patients. In all patients, rates of propofol and remifentanil providing a steady-state level of hypnosis (BIS: 40-60) were maintained constant throughout a recording period ranging from 3 minutes before CXC to shunt insertion. BIS was recorded throughout this period and the internal carotid backflow observed at the time of shunt insertion was graded as good, moderate, or poor. In addition, A-Line Autoregressive Index (AAI) and processed electroencephalogram (EEG) parameters were recorded in patients of the study group. All parameters were averaged over I minute before CXC, at CXC, 1, 2, and 3 minutes after CXC, and at shunt insertion. Statistical analysis was performed using X 2, Friedman, and Spearman correlation tests. For technical reasons, reliable AAI, BIS monitor-derived, and other processed EEG data were obtained in 24, 25, and 18 patients of the study group, respectively. During the first 3 minutes after CXC, BIS increased over 60 [68.8 (6.1)] in 47%, decreased below 40 [34.9 (4.4)] in 25%, and remained in the 40 to 60 range in 28% of all recruited patients. A BIS increase was more frequently observed in patients with moderate or poor than in those with good internal carotid backflow (78, 67, and 29%, respectively). It was significantly correlated to an increase in AAI and EEG amplitude, a decrease in EEG suppression ratio, and a shorter time between induction of anesthesia and CXC. A BIS decrease was significantly correlated to an increase in suppression ratio and a longer time between induction and CXC. In conclusion, during CXC under a constant level of intravenous anesthesia, BIS may increase, decrease, or remain unchanged. The paradoxical BIS increase could be related to borderline ischemia, a change in brain anesthetic agent concentration, or a change in the nociceptive-antinociceptive balance associated with a CXC-elicited painful stimulation. Caution should be used when interpreting BIS value during CXC

Deciphering the response of subventricular zone-nested glioblastoma cells after surgery

INTRODUCTION: Glioblastoma (GBM) is the most frequent primary malignant brain tumor in adults, with really poor prognosis, subsequent to systematic recurrences, which occur in 80% of cases in the resection margin of initial tumor. We previously demonstrated that, after experimental striatal xenotransplantation, GBM cells, and particularly GBM-initiating cells (GIC), are able to escape the tumor mass and specifically colonize the sub-ventricular zone (SVZ), a well-known neurogenic zone in adult brains. We also demonstrated that this specific oriented migration is driven by a CXCL12-CXCR4 signalization. In this study, we address the potential implication of SVZ-nested tumor cells in local GBM relapses. MATERIALS AND METHODS: We engrafted in the right striatum of nude mice GBM cells (GB138) from a human primary culture, which are previously transfected with a lentiviral construction in order to express the RFP spontaneously, while they conditionally express eGFP, only in presence of Cre-recombinase. As the GB138 cells reach the SVZ, we injected in the lateral ventricle an Adeno-Associated Viral vector expressing Cre-recombinase, which is able to infect nearby GB138 cells. We finally compared 3 mice that were not operated (control group) with 3 mice that underwent tumor resection (surgery group) and quantify green spots in the tumor mass (TM) and/or resection cavity (RC) every 20 microns thanks to Clarity Lightsheet microscope. RESULTS: We found that the median of green spots for the 3 mice of the control group was respectively 1, 0 and 0 in TM, while the median for the surgery group was 7, 8 and 47 in RC. The Standard Deviation (SD) for the control group was respectively 1.1, 0.4 and 0.6, while SD for the surgery group was respectively 1.5, 1.7 and 16. CONCLUSION: SVZ-nested GBM cells seem to be recruited for tumor relapse after surgery