Lateralisation of subcortical functional connectivity during and after general anaesthesia.

BACKGROUND: Arousal and awareness are two important components of consciousness states. Functional neuroimaging has furthered our understanding of cortical and thalamocortical mechanisms of awareness. Investigating the relationship between subcortical functional connectivity and arousal has been challenging owing to the relatively small size of brainstem structures and thalamic nuclei, and their depth in the brain. METHODS: Resting state functional MRI scans of 72 healthy volunteers were acquired before, during, 1 h after, and 1 day after sevoflurane general anaesthesia. Functional connectivity of subcortical regions of interest vs whole brain and homotopic functional connectivity for assessment of left-right symmetry analyses of both cortical and subcortical regions of interest were performed. Both analyses used high resolution atlases generated from deep brain stimulation applications. RESULTS: Functional connectivity in subcortical loci within the thalamus and of the ascending reticular activating system was sharply restricted under anaesthesia, featuring a general lateralisation of connectivity. Similarly, left-right homology was sharply reduced under anaesthesia. Subcortical bilateral functional connectivity was not fully restored after emergence from anaesthesia, although greater restoration was seen between ascending reticular activating system loci and specific thalamic nuclei thought to be involved in promoting and maintaining arousal. Functional connectivity was fully restored to baseline by the following day. CONCLUSIONS: Functional connectivity in the subcortex is sharply restricted and lateralised under general anaesthesia. This restriction may play a part in loss and return of consciousness. CLINICAL TRIAL REGISTRATION: NCT02275026.

Alterations of plasma metabolite profiles related to adipose tissue distribution and cardiometabolic risk.

Metabolomic profiling of obese individuals revealed altered concentrations of many metabolites, especially branched-chain amino acids (BCAA), possibly linked to altered adipose tissue BCAA catabolism. We tested the hypothesis that some features of this metabolite signature relate closely to visceral obesity and concomitant alterations in cardiometabolic risk factors. We also postulated that alterations in BCAA-catabolizing enzymes are predominant in visceral adipose tissue. Fifty-nine women (BMI 20-41 kg/m(2)) undergoing gynecologic surgery were recruited and characterized for overall and regional adiposity, blood metabolite levels using targeted metabolomics, and cardiometabolic risk factors. Adipose samples (visceral and subcutaneous) were obtained and used for gene expression and Western blot analyses. Obese women had significantly higher circulating BCAA and kynurenine/tryptophan (Kyn/Trp) ratio than lean or overweight women (P < 0.01). Principal component analysis confirmed that factors related to AA and the Kyn/Trp ratio were positively associated with BMI, fat mass, visceral or subcutaneous adipose tissue area, and subcutaneous adipocyte size (P ≤ 0.05). AA-related factor was positively associated with HOMA-IR (P ≤ 0.01). Factors reflecting glycerophospholipids and sphingolipids levels were mostly associated with altered blood lipid concentrations (P ≤ 0.05). Glutamate level was the strongest independent predictor of visceral adipose tissue area (r = 0.46, P < 0.001). Obese women had lower expression and protein levels of BCAA-catabolizing enzymes in visceral adipose tissue than overweight or lean women (P ≤ 0.05). We conclude that among metabolites altered in obesity plasma concentrations of BCAA and the Kyn/Trp ratio are closely related to increased adiposity. Alterations in expression and protein levels of BCAA-catabolizing enzymes are predominant in visceral adipose tissue.

Space exploration as a catalyst for medical innovations.

Aerospace research has a long history of developing technologies with industry-changing applications and recent history is no exception. The expansion of commercial spaceflight and the upcoming exploration-class missions to the Moon and Mars are expected to accelerate this process even more. The resulting portable, wearable, contactless, and regenerable medical technologies are not only the future of healthcare in deep space but also the future of healthcare here on Earth. These multi-dimensional and integrative technologies are non-invasive, easily-deployable, low-footprint devices that have the ability to facilitate rapid detection, diagnosis, monitoring, and treatment of a variety of conditions, and to provide decision-making and performance support. Therefore, they are primed for applications in low-resource and remote environments, facilitating the extension of quality care delivery to all patients in all communities and empowering non-specialists to intervene early and safely in order to optimize patient-centered outcomes. Additionally, these technologies have the potential to advance care delivery in tertiary care centers by improving transitions of care, providing holistic patient data, and supporting clinician wellness and performance. The requirements of space exploration have created a number of paradigm-altering medical technologies that are primed to revitalize and elevate our standard of care here on Earth.

The role for regional anesthesia in medical emergencies during deep space flight.

As humanity presses the boundaries of space exploration and prepares for long-term interplanetary travel, including to Mars, advanced planning for the safety and health of the crewmembers requires a multidisciplinary approach. In particular, in the event of a survivable medical emergency requiring an interventional procedure or prolonged pain management, such as traumatic limb injury or rib fracture, anesthetic protocols that are both safe and straightforward to execute must be in place. In this daring discourse, we discuss particular considerations related to the use of regional techniques in space and present the rationale that regional anesthesia techniques may be the safest option in many medical emergencies encountered during prolonged space flight.