Impact of cerebral blood flow level on the fluctuations of resting-state BOLD fMRI in anesthetized rats

International audienceThe Blood Oxygen Level Dependent (BOLD) signal, used in resting-state functional Magnetic Resonance Imaging (fMRI), is tighly linked to Cerebral Blood Flow (CBF). This study evaluates the impact of the CBF on the low-frequencies BOLD fluctuations and four physiological parameters during resting state in 5 groups of rats (Wistar and Long-Evans) anesthetized with Isoflurane, Medetomidine, Etomidate and Urethane. It is shown that the CBF is not related to physiological parameters, and there exists a range of CBF values where the BOLD fluctations are sufficiently high for being used in any other analysis

Functional connectivity is preserved but reorganized across several anesthetic regimes

International audienceUnder anesthesia, systemic variables and CBF are modified. How does this alter the connectivity measures obtained with rs-fMRI? To tackle this question, we explored the effect of four different anesthetics on Long Evans and Wistar rats with multimodal recordings of rs-fMRI, systemic variables and CBF. After multimodal signal processing, we show that the blood-oxygen-level-dependent (BOLD) variations and functional connectivity (FC) evaluated at low frequencies (0.031-0.25 Hz) do not depend on systemic variables and are preserved across a large interval of baseline CBF values. Based on these findings, we found that most brain areas remain functionally active under any anesthetics, i.e. connected to at least one other brain area, as shown by the connectivity graphs. In addition, we quantified the influence of nodes by a measure of functional connectivity strength to show the specific areas targeted by anesthetics and compare correlation values of edges at different levels. These measures enable us to highlight the specific network alterations induced by anesthetics. Altogether, this suggests that changes in connectivity could be evaluated under anesthesia, routinely used in the control of neurological injury

Relationship between serotypes, disease characteristics and 30-day mortality in adults with invasive pneumococcal disease

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More Than 50 Percent Reduction in LDL Cholesterol in Patients With Target LDL <70 mg/dL After a Stroke

International audienceBACKGROUND: Whether a strategy to target an LDL (low-density lipoprotein) cholesterol 50% from baseline rather than 50% LDL cholesterol reduction from baseline during the trial had a higher baseline LDL cholesterol and a lower LDL cholesterol achieved as compared to patients who had 50% LDL reduction had a significant reduction in the primary outcome as compared to the higher target group (hazard ratio, 0.61 [95% CI, 0.43–0.88]; P =0.007) and patients with <50% LDL reduction from baseline had little reduction (hazard ratio, 0.96 [95% CI, 0.73–1.26]; P =0.75). CONCLUSIONS: In this post hoc analysis of the TST trial, targeting an LDL cholesterol of <70 mg/dL reduced the risk of primary outcome compared with 100±10 mg/dL provided LDL cholesterol reduction from baseline was superior to 50%, thereby suggesting that the magnitude of LDL cholesterol reduction was as important to consider as the target level to achieve. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT01252875. URL: https://clinicaltrialsregister.eu ; Unique identifier: EUDRACT2009-A01280-57.gov; Unique identifier: NCT01252875. URL: https://clinicaltrialsregister.eu; Unique identifier: EUDRACT2009-A01280-57.URL: https://www