scholarly journals An international collaboration studying the physiological and anatomical cerebral effects of carbon dioxide during head-down tilt bed rest: the SPACECOT study

2017 ◽  
Vol 122 (6) ◽  
pp. 1398-1405 ◽  
Author(s):  
Karina Marshall-Goebel ◽  
Edwin Mulder ◽  
Dorit Donoviel ◽  
Gary Strangman ◽  
Jose I. Suarez ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Space Station ◽  
Environmental Parameters ◽  
Bed Rest ◽  
Ambient Air ◽  
Microgravity Environment ◽  
Double Blind ◽  
New Approach ◽  
Anatomy And Physiology ◽  
Standardization Plan

Exposure to the microgravity environment results in various adaptive and maladaptive physiological changes in the human body, with notable ophthalmic abnormalities developing during 6-mo missions on the International Space Station (ISS). These findings have led to the hypothesis that the loss of gravity induces a cephalad fluid shift, decreased cerebral venous outflow, and increased intracranial pressure, which may be further exacerbated by increased ambient carbon dioxide (CO2) levels on the ISS. Here we describe the SPACECOT study (studying the physiological and anatomical cerebral effects of CO2 during head-down tilt), a randomized, double-blind crossover design study with two conditions: 29 h of 12° head-down tilt (HDT) with ambient air and 29 h of 12° HDT with 0.5% CO2. The internationally collaborative SPACECOT study utilized an innovative approach to study the effects of headward fluid shifting induced by 12° HDT and increased ambient CO2 as well as their interaction with a focus on cerebral and ocular anatomy and physiology. Here we provide an in-depth overview of this new approach including the subjects, study design, and implementation, as well as the standardization plan for nutritional intake, environmental parameters, and bed rest procedures. NEW & NOTEWORTHY A new approach for investigating the combined effects of cephalad fluid shifting and increased ambient carbon dioxide (CO2) is presented. This may be useful for studying the neuroophthalmic and cerebral effects of spaceflight where cephalad fluid shifts occur in an elevated CO2 environment.

scholarly journals Visuomotor Adaptation Brain Changes During a Spaceflight Analog With Elevated Carbon Dioxide (CO2): A Pilot Study

2021 ◽  
Vol 15 ◽  
Author(s):  
Ana Paula Salazar ◽  
Kathleen E. Hupfeld ◽  
Jessica K. Lee ◽  
Lauren A. Banker ◽  
Grant D. Tays ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Brain Activity ◽  
Space Station ◽  
Bed Rest ◽  
Elevated Carbon Dioxide ◽  
Visuomotor Adaptation ◽  
Brain Regions ◽  
Brain Changes ◽  
Carbon Dioxide Co2 ◽  
Adaptation Task

Astronauts on board the International Space Station (ISS) must adapt to several environmental challenges including microgravity, elevated carbon dioxide (CO2), and isolation while performing highly controlled movements with complex equipment. Head down tilt bed rest (HDBR) is an analog used to study spaceflight factors including body unloading and headward fluid shifts. We recently reported how HDBR with elevated CO2 (HDBR+CO2) affects visuomotor adaptation. Here we expand upon this work and examine the effects of HDBR+CO2 on brain activity during visuomotor adaptation. Eleven participants (34 ± 8 years) completed six functional MRI (fMRI) sessions pre-, during, and post-HDBR+CO2. During fMRI, participants completed a visuomotor adaptation task, divided into baseline, early, late and de-adaptation. Additionally, we compare brain activity between this NASA campaign (30-day HDBR+CO2) and a different campaign with a separate set of participants (60-day HDBR with normal atmospheric CO2 levels, n = 8; 34.25 ± 7.9 years) to characterize the specific effects of CO2. Participants were included by convenience. During early adaptation across the HDBR+CO2 intervention, participants showed decreasing activation in temporal and subcortical brain regions, followed by post- HDBR+CO2 recovery. During late adaptation, participants showed increasing activation in the right fusiform gyrus and right caudate nucleus during HDBR+CO2; this activation normalized to baseline levels after bed rest. There were no correlations between brain changes and adaptation performance changes from pre- to post HDBR+CO2. Also, there were no statistically significant differences between the HDBR+CO2 group and the HDBR controls, suggesting that changes in brain activity were due primarily to bed rest rather than elevated CO2. Five HDBR+CO2 participants presented with optic disc edema, a sign of Spaceflight Associated Neuro-ocular Syndrome (SANS). An exploratory analysis of HDBR+CO2 participants with and without signs of SANS revealed no group differences in brain activity during any phase of the adaptation task. Overall, these findings have implications for spaceflight missions and training, as ISS missions require individuals to adapt to altered sensory inputs over long periods in space. Further, this is the first study to verify the HDBR and elevated CO2 effects on the neural correlates of visuomotor adaptation.

scholarly journals Brain Connectivity and Behavioral Changes in a Spaceflight Analog Environment with Elevated CO2

2020 ◽  
Author(s):  
Heather R. McGregor ◽  
Jessica K. Lee ◽  
Edwin R. Mulder ◽  
Yiri E. De Dios ◽  
Nichole E. Beltran ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Resting State ◽  
Time Course ◽  
Brain Connectivity ◽  
Space Station ◽  
Bed Rest ◽  
Ambient Air ◽  
Control Group ◽  
Resting State Functional Connectivity ◽  
Sensorimotor Performance

ABSTRACTAstronauts are exposed to microgravity and elevated CO2 levels onboard the International Space Station. Little is known about how microgravity and elevated CO2 combine to affect the brain and sensorimotor performance during and after spaceflight. Here we examined changes in resting-state functional connectivity (FC) and sensorimotor behavior associated with a spaceflight analog environment. Participants underwent 30 days of strict 6° head-down tilt bed rest with elevated ambient CO2 (HDBR+CO2). Resting-state functional magnetic resonance imaging and sensorimotor assessments were collected 13 and 7 days prior to bed rest, on days 7 and 29 of bed rest, and 0, 5, 12, and 13 days following bed rest. We assessed the time course of FC changes from before, during, to after HDBR+CO2. We then compared the observed connectivity changes with those of a HDBR control group, which underwent HDBR in standard ambient air. Moreover, we assessed associations between post-HDBR+CO2 FC changes and alterations in sensorimotor performance. HDBR+CO2 was associated with significant changes in functional connectivity between vestibular, visual, somatosensory and motor brain areas. Several of these sensory and motor regions showed post-HDBR+CO2 FC changes that were significantly associated with alterations in sensorimotor performance. We propose that these FC changes reflect multisensory reweighting associated with adaptation to the HDBR+CO2 microgravity analog environment. This knowledge will further improve HDBR as a model of microgravity exposure and contribute to our knowledge of brain and performance changes during and after spaceflight.

scholarly journals Ophthalmic Changes in a Spaceflight Analog Are Associated with Brain Functional Reorganization

2020 ◽  
Author(s):  
Heather R. McGregor ◽  
Jessica K. Lee ◽  
Edwin R. Mulder ◽  
Yiri E. De Dios ◽  
Nichole E. Beltran ◽  
...  
Keyword(s):  
Functional Connectivity ◽  
Optic Disc ◽  
Resting State ◽  
Large Scale ◽  
Space Station ◽  
Bed Rest ◽  
Ambient Air ◽  
Resting State Functional Connectivity ◽  
Optic Disc Edema ◽  
Disc Edema

ABSTRACTImportanceFollowing long-duration missions onboard the International Space Station, some astronauts develop ophthalmic abnormalities collectively referred to as Spaceflight Associated Neuro-ocular Syndrome (SANS). Optic disc edema is a common sign of SANS. SANS presents significant potential risk to astronaut health and performance; however, the origin and effects of SANS are not understood as signs of SANS have not manifested in previous spaceflight analog studies.ObjectiveTo investigate whether development of optic disc edema during a spaceflight analog impacts resting-state functional connectivity.Design, Setting and ParticipantsEleven healthy volunteers participated in this 58-day longitudinal study conducted at the :envihab facility at the German Aerospace Center.Interventions or ExposuresBaseline data were collected during a 14-day ambulatory phase in standard ambient air. All participants then underwent a spaceflight analog intervention: 30 days of strict head-down tilt bed rest in elevated ambient carbon dioxide (HDBR+CO2). The elevated CO2 level (0.5%) was matched to the hypercapnic environment of the International Space Station. The intervention was followed by a 14-day ambulatory recovery phase in standard ambient air. During the HDBR+CO2 spaceflight analog, 5 participants developed optic disc edema (SANS subgroup) and 6 did not (NoSANS group).Main Outcomes and MeasuresUsing functional magnetic resonance imaging (fMRI), we acquired resting-state data at 6 time points throughout the study: before (2), during (2), and after (2) the HDBR+CO2 intervention. We assessed the time course of resting-state functional connectivity changes from before, during, to after the HDBR+CO2, and contrasted longitudinal changes between the SANS and NoSANS subgroups. We also assessed if the SANS and NoSANS subgroups exhibited differential patterns of resting-state functional connectivity prior to the HDBR+CO2 intervention.ResultsThe SANS and NoSANS subgroups exhibited differential patterns of resting-state connectivity changes during the HDBR+CO2 spaceflight analog within visual and vestibular-related brain networks. We further found that the SANS and NoSANS subgroups exhibited differential resting-state brain activity prior to the spaceflight analog within a visual cortical network and within a large-scale network of brain areas involved in multisensory integration.Conclusions and RelevanceSubgroup differences in resting-state functional connectivity changes may reflect differential patterns of visual and vestibular reweighting as optic disc edema develops during the HDBR+CO2 spaceflight analog. This finding suggests that SANS impacts not only neuro-ocular structures, but also brain function. Future prospective investigations incorporating sensory assessments are required to determine the functional significance of the observed connectivity differences.KEY POINTSQuestionDoes optic disc edema development during head-down tilt bed rest with elevated carbon dioxide impact brain resting-state functional connectivity?FindingsA subset of participants developed optic disc edema during the head-down tilt bed rest intervention with elevated ambient CO2. Participants who developed optic disc edema exhibited a distinct pattern of resting-state functional connectivity changes within visual and vestibular-related networks during the spaceflight analog compared to participants who did not. Participants who developed optic disc edema exhibited different resting-state brain activity prior to the spaceflight analog within a visual cortical network and within a large-scale network of brain areas involved in multisensory integration.MeaningDevelopment of optic disc edema was associated with distinct patterns of brain resting-state functional connectivity during and prior to the spaceflight analog.

scholarly journals Non-Steroidal Anti-Inflammatory Drugs in Colorectal Cancer Chemoprevention

Cancers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 594
Author(s):  
Jadwiga Maniewska ◽  
Dagmara Jeżewska
Keyword(s):  
Colorectal Cancer ◽  
Cell Proliferation ◽  
Clinical Trials ◽  
Cancer Chemoprevention ◽  
Tumor Cell Proliferation ◽  
Double Blind ◽  
New Approach ◽  
Randomized Controlled ◽  
Inflammatory Drugs ◽  
Chemopreventive Effect

Since colorectal cancer is one of the world’s most common cancers, studies on its prevention and early diagnosis are an emerging area of clinical oncology these days. For this study, a review of randomized controlled, double-blind clinical trials of selected NSAIDs (aspirin, sulindac and celecoxib) in chemoprevention of colorectal cancer was conducted. The main molecular anticancer activity of NSAIDs is thought to be a suppression of prostaglandin E2 synthesis via cyclooxygenase-2 inhibition, which causes a decrease in tumor cell proliferation, angiogenesis, and increases apoptosis. The lower incidence of colorectal cancer in the NSAID patients suggests the long-lasting chemopreventive effect of drugs studied. This new approach to therapy of colorectal cancer may transform the disease from a terminal to a chronic one that can be taken under control.

Moisture induced isotopic carbon dioxide trapping from ambient air

2016 ◽  
Vol 4 (20) ◽  
pp. 7632-7640 ◽  
Author(s):  
Sankar Das ◽  
Chiranjit Ghosh ◽  
Subhra Jana
Keyword(s):  
Carbon Dioxide ◽  
Ambient Air ◽  
Solid Adsorbents

Clay based solid adsorbents comprised of several viable amines have been developed to capture isotopic CO2 from the ambient air, keeping an eye on the moisture induced CO2 adsorption.

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