The Experts below are selected from a list of 26346 Experts worldwide ranked by ideXlab platform
Alan R. Hargens - One of the best experts on this subject based on the ideXlab platform.
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Spaceflight induced intracranial hypertension and visual impairment pathophysiology and countermeasures
Physiological Reviews, 2018Co-Authors: Alan R. Hargens, Lifan ZhangAbstract:Visual impairment intracranial pressure (VIIP) syndrome is considered an unexplained major risk for future long-duration Spaceflight. NASA recently redefined this syndrome as Spaceflight-Associated...
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lumbar spine paraspinal muscle and intervertebral disc height changes in astronauts after long duration Spaceflight on the international space station
Spine, 2016Co-Authors: Douglas G Chang, Brandon R Macias, Robert M Healey, Alexander J Snyder, Jojo V Sayson, Dezba Coughlin, Jeannie F Bailey, Scott E Parazynski, Jeffrey C Lotz, Alan R. HargensAbstract:STUDY DESIGN: Prospective case series. OBJECTIVE: Evaluate lumbar paraspinal muscle (PSM) cross-sectional area and intervertebral disc (IVD) height changes induced by a 6-month space mission on the International Space Station. The long-term objective of this project is to promote spine health and prevent spinal injury during space missions and here on Earth. SUMMARY OF BACKGROUND DATA: National Aeronautics and Space Administration (NASA) crewmembers have a 4.3 times higher risk of herniated IVDs, compared with the general and military aviator populations. The highest risk occurs during the first year after a mission. Microgravity exposure during long-duration Spaceflights results in approximately 5 cm lengthening of body height, spinal pain, and skeletal deconditioning. How the PSMs and IVDs respond during Spaceflight is not well described. METHODS: Six NASA crewmembers were imaged supine with a 3 Tesla magnetic resonance imaging. Imaging was conducted preflight, immediately postflight, and then 33 to 67 days after landing. Functional cross-sectional area (FCSA) measurements of the PSMs were performed at the L3-4 level. FCSA was measured by grayscale thresholding within the posterior lumbar extensors to isolate lean muscle on T2-weighted scans. IVD heights were measured at the anterior, middle, and posterior sections of all lumbar levels. Repeated measures analysis of variance was used to determine significance at P < 0.05, followed by post-hoc testing. RESULTS: Paraspinal lean muscle mass, as indicated by the FCSA, decreased from 86% of the total PSM cross-sectional area down to 72%, immediately after the mission. Recovery of 68% of the postflight loss occurred during the next 6 weeks, still leaving a significantly lower lean muscle fractional content compared with preflight values. In contrast, lumbar IVD heights were not appreciably different at any time point. CONCLUSION: The data reveal lumbar spine PSM atrophy after long-duration Spaceflight. Some FCSA recovery was seen with 46 days postflight in a terrestrial environment, but it remained incomplete compared with preflight levels. LEVEL OF EVIDENCE: 4.
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Maximizing information from space data resources: a case for expanding integration across research disciplines
European Journal of Applied Physiology, 2013Co-Authors: Nandu Goswami, Alan R. Hargens, Jerry J. Batzel, Gilles Clément, T. Peter Stein, M. Keith Sharp, Andrew P. Blaber, Peter G. Roma, Helmut G. Hinghofer-szalkayAbstract:Regulatory systems are affected in space by exposure to weightlessness, high-energy radiation or other Spaceflight-induced changes. The impact of Spaceflight occurs across multiple scales and systems. Exploring such interactions and interdependencies via an integrative approach provides new opportunities for elucidating these complex responses. This paper argues the case for increased emphasis on integration, systematically archiving, and the coordination of past, present and future space and ground-based analogue experiments. We also discuss possible mechanisms for such integration across disciplines and missions. This article then introduces several discipline-specific reviews that show how such integration can be implemented. Areas explored include: adaptation of the central nervous system to space; cerebral autoregulation and weightlessness; modelling of the cardiovascular system in space exploration; human metabolic response to Spaceflight; and exercise, artificial gravity, and physiologic countermeasures for Spaceflight. In summary, Spaceflight physiology research needs a conceptual framework that extends problem solving beyond disciplinary barriers. Administrative commitment and a high degree of cooperation among investigators are needed to further such a process. Well-designed interdisciplinary research can expand opportunities for broad interpretation of results across multiple physiological systems, which may have applications on Earth.
Annsofie Schreurs - One of the best experts on this subject based on the ideXlab platform.
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dietary countermeasure mitigates simulated Spaceflight induced osteopenia in mice
Scientific Reports, 2020Co-Authors: Sonette Steczina, Candice Tahimic, Megan M Pendleton, Ons Msaad, Moniece Lowe, Joshua S Alwood, Bernard P Halloran, Ruth K Globus, Annsofie SchreursAbstract:Spaceflight is a unique environment that includes at least two factors which can negatively impact skeletal health: microgravity and ionizing radiation. We have previously shown that a diet supplemented with dried plum powder (DP) prevented radiation-induced bone loss in mice. In this study, we investigated the capacity of the DP diet to prevent bone loss in mice following exposure to simulated Spaceflight, combining microgravity (by hindlimb unloading) and radiation exposure. The DP diet was effective at preventing most decrements in bone micro-architectural and mechanical properties due to hindlimb unloading alone and simulated Spaceflight. Furthermore, we show that the DP diet can protect osteoprogenitors from impairments resulting from simulated microgravity. Based on our findings, a dietary supplementation with DP could be an effective countermeasure against the skeletal deficits observed in astronauts during Spaceflight.
Aurelie Crabbe - One of the best experts on this subject based on the ideXlab platform.
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Efficacy of Antimicrobials on Bacteria Cultured in a Spaceflight Analogue
2014Co-Authors: Cheryl A Nickerson, Aurelie Crabbe, Jennifer Barrila, Richard R Davis, Virginia Wotring, Sarah L. Castro, April Rideout, Breanne MccarthyAbstract:As humans travel in space, they will interact with microbial flora from themselves, other crewmembers, their food, and the environment. While evaluations of microbial ecology aboard the Mir and ISS suggest a predominance of common environmental flora, the presence of (and potential for) infectious agents has been well documented. Likewise, pathogens have been detected during preflight monitoring of Spaceflight food, resulting in the disqualification of that production lot from flight. These environmental and food organisms range from the obligate pathogen, Salmonella enterica serovar Typhimurium (S. Typhimurium), which has been responsible for disqualification and removal of food destined for ISS and has previously been reported from Shuttle crew refuse, to the opportunistic pathogen Staphylococcus aureus, isolated numerous times from ISS habitable compartments and the crew. Infectious disease events have affected Spaceflight missions, including an upper respiratory infection that delayed the launch of STS-36 and an incapacitating Pseudomonas aeruginosa urinary tract infection of a crewmember during Apollo 13. These observations indicate that the crew has the potential to be exposed to obligate and opportunistic pathogens. This risk of exposure is expected to increase with longer mission durations and increased use of regenerative life support systems. As antibiotics are the primary countermeasure after infection, determining if their efficacy during Spaceflight missions is comparable to terrestrial application is of critical importance. The NASA Rotating Wall Vessel (RWV) culture system has been successfully used as a Spaceflight culture analogue to identify potential alterations in several key microbial characteristics, such as virulence and gene regulation, in response to Spaceflight culture. We hypothesized that bacteria cultured in the low fluid shear RWV environment would demonstrate changes in efficacy of antibiotics compared to higher fluid shear controls. This study investigated the response of three medically significant microorganisms grown in the RWV to antibiotics that could be used on Spaceflight missions. Our findings suggest potential alterations in antibiotic efficacy during Spaceflight and indicate that future studies on the antibiotic response require additional basic research using the RWV and/or true Spaceflight. However, while this analogue has reinforced these potential alterations, the results suggest the best approach for applied forward work is evaluating an in vivo system during Spaceflight, including human and rodent studies. The complex nature of the analysis for many antibiotics and organism suggests the best approach to determine in vivo responses during pharmaceutical treatment is evaluating an in vivo system during Spaceflight.
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Spaceflight enhances cell aggregation and random budding in candida albicans
PLOS ONE, 2013Co-Authors: Aurelie Crabbe, Sheila M Nielsenpreiss, Christine M Woolley, Jennifer Barrila, Kent L Buchanan, James P Mccracken, Diane O Inglis, Stephen C SearlesAbstract:This study presents the first global transcriptional profiling and phenotypic characterization of the major human opportunistic fungal pathogen, Candida albicans, grown in Spaceflight conditions. Microarray analysis revealed that C. albicans subjected to short-term Spaceflight culture differentially regulated 452 genes compared to synchronous ground controls, which represented 8.3% of the analyzed ORFs. Spaceflight-cultured C. albicans–induced genes involved in cell aggregation (similar to flocculation), which was validated by microscopic and flow cytometry analysis. We also observed enhanced random budding of Spaceflight-cultured cells as opposed to bipolar budding patterns for ground samples, in accordance with the gene expression data. Furthermore, genes involved in antifungal agent and stress resistance were differentially regulated in Spaceflight, including induction of ABC transporters and members of the major facilitator family, downregulation of ergosterol-encoding genes, and upregulation of genes involved in oxidative stress resistance. Finally, downregulation of genes involved in actin cytoskeleton was observed. Interestingly, the transcriptional regulator Cap1 and over 30% of the Cap1 regulon was differentially expressed in Spaceflight-cultured C. albicans. A potential role for Cap1 in the Spaceflight response of C. albicans is suggested, as this regulator is involved in random budding, cell aggregation, and oxidative stress resistance; all related to observed Spaceflight-associated changes of C. albicans. While culture of C. albicans in microgravity potentiates a global change in gene expression that could induce a virulence-related phenotype, no increased virulence in a murine intraperitoneal (i.p.) infection model was observed under the conditions of this study. Collectively, our data represent an important basis for the assessment of the risk that commensal flora could play during human Spaceflight missions. Furthermore, since the low fluid-shear environment of microgravity is relevant to physical forces encountered by pathogens during the infection process, insights gained from this study could identify novel infectious disease mechanisms, with downstream benefits for the general public.
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transcriptional and proteomic responses of pseudomonas aeruginosa pao1 to Spaceflight conditions involve hfq regulation and reveal a role for oxygen
Applied and Environmental Microbiology, 2011Co-Authors: Aurelie Crabbe, Duane L Pierson, Michael J Schurr, Pieter Monsieurs, Lisa A Morici, Jill Schurr, James W Wilson, George Tsaprailis, Heidi Stefanyshynpiper, Cheryl A NickersonAbstract:Assessing bacterial behavior in microgravity is important for risk assessment and prevention of infectious diseases during Spaceflight missions. Furthermore, this research field allows the unveiling of novel connections between low-fluid-shear regions encountered by pathogens during their natural infection process and bacterial virulence. This study is the first to characterize the Spaceflight-induced global transcriptional and proteomic responses of Pseudomonas aeruginosa, an opportunistic pathogen that is present in the space habitat. P. aeruginosa responded to Spaceflight conditions through differential regulation of 167 genes and 28 proteins, with Hfq as a global transcriptional regulator. Since Hfq was also differentially regulated in Spaceflight-grown Salmonella enterica serovar Typhimurium, Hfq represents the first Spaceflight-induced regulator acting across bacterial species. The major P. aeruginosa virulence-related genes induced in Spaceflight were the lecA and lecB lectin genes and the gene for rhamnosyltransferase (rhlA), which is involved in rhamnolipid production. The transcriptional response of Spaceflight-grown P. aeruginosa was compared with our previous data for this organism grown in microgravity analogue conditions using the rotating wall vessel (RWV) bioreactor. Interesting similarities were observed, including, among others, similarities with regard to Hfq regulation and oxygen metabolism. While RWV-grown P. aeruginosa mainly induced genes involved in microaerophilic metabolism, P. aeruginosa cultured in Spaceflight presumably adopted an anaerobic mode of growth, in which denitrification was most prominent. Whether the observed changes in pathogenesis-related gene expression in response to Spaceflight culture could lead to an alteration of virulence in P. aeruginosa remains to be determined and will be important for infectious disease risk assessment and prevention, both during Spaceflight missions and for the general public.
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media ion composition controls regulatory and virulence response of salmonella in Spaceflight
PLOS ONE, 2008Co-Authors: Aurelie Crabbe, James W Wilson, Laura N Quick, Richard R Davis, Kerstin Honer Zu Bentrup, Emily Richter, Shameema Sarker, Jennifer BarrilaAbstract:The Spaceflight environment is relevant to conditions encountered by pathogens during the course of infection and induces novel changes in microbial pathogenesis not observed using conventional methods. It is unclear how microbial cells sense Spaceflight-associated changes to their growth environment and orchestrate corresponding changes in molecular and physiological phenotypes relevant to the infection process. Here we report that Spaceflight-induced increases in Salmonella virulence are regulated by media ion composition, and that phosphate ion is sufficient to alter related pathogenesis responses in a Spaceflight analogue model. Using whole genome microarray and proteomic analyses from two independent Space Shuttle missions, we identified evolutionarily conserved molecular pathways in Salmonella that respond to Spaceflight under all media compositions tested. Identification of conserved regulatory paradigms opens new avenues to control microbial responses during the infection process and holds promise to provide an improved understanding of human health and disease on Earth.
James W Wilson - One of the best experts on this subject based on the ideXlab platform.
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transcriptional and proteomic responses of pseudomonas aeruginosa pao1 to Spaceflight conditions involve hfq regulation and reveal a role for oxygen
Applied and Environmental Microbiology, 2011Co-Authors: Aurelie Crabbe, Duane L Pierson, Michael J Schurr, Pieter Monsieurs, Lisa A Morici, Jill Schurr, James W Wilson, George Tsaprailis, Heidi Stefanyshynpiper, Cheryl A NickersonAbstract:Assessing bacterial behavior in microgravity is important for risk assessment and prevention of infectious diseases during Spaceflight missions. Furthermore, this research field allows the unveiling of novel connections between low-fluid-shear regions encountered by pathogens during their natural infection process and bacterial virulence. This study is the first to characterize the Spaceflight-induced global transcriptional and proteomic responses of Pseudomonas aeruginosa, an opportunistic pathogen that is present in the space habitat. P. aeruginosa responded to Spaceflight conditions through differential regulation of 167 genes and 28 proteins, with Hfq as a global transcriptional regulator. Since Hfq was also differentially regulated in Spaceflight-grown Salmonella enterica serovar Typhimurium, Hfq represents the first Spaceflight-induced regulator acting across bacterial species. The major P. aeruginosa virulence-related genes induced in Spaceflight were the lecA and lecB lectin genes and the gene for rhamnosyltransferase (rhlA), which is involved in rhamnolipid production. The transcriptional response of Spaceflight-grown P. aeruginosa was compared with our previous data for this organism grown in microgravity analogue conditions using the rotating wall vessel (RWV) bioreactor. Interesting similarities were observed, including, among others, similarities with regard to Hfq regulation and oxygen metabolism. While RWV-grown P. aeruginosa mainly induced genes involved in microaerophilic metabolism, P. aeruginosa cultured in Spaceflight presumably adopted an anaerobic mode of growth, in which denitrification was most prominent. Whether the observed changes in pathogenesis-related gene expression in response to Spaceflight culture could lead to an alteration of virulence in P. aeruginosa remains to be determined and will be important for infectious disease risk assessment and prevention, both during Spaceflight missions and for the general public.
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media ion composition controls regulatory and virulence response of salmonella in Spaceflight
PLOS ONE, 2008Co-Authors: Aurelie Crabbe, James W Wilson, Laura N Quick, Richard R Davis, Kerstin Honer Zu Bentrup, Emily Richter, Shameema Sarker, Jennifer BarrilaAbstract:The Spaceflight environment is relevant to conditions encountered by pathogens during the course of infection and induces novel changes in microbial pathogenesis not observed using conventional methods. It is unclear how microbial cells sense Spaceflight-associated changes to their growth environment and orchestrate corresponding changes in molecular and physiological phenotypes relevant to the infection process. Here we report that Spaceflight-induced increases in Salmonella virulence are regulated by media ion composition, and that phosphate ion is sufficient to alter related pathogenesis responses in a Spaceflight analogue model. Using whole genome microarray and proteomic analyses from two independent Space Shuttle missions, we identified evolutionarily conserved molecular pathways in Salmonella that respond to Spaceflight under all media compositions tested. Identification of conserved regulatory paradigms opens new avenues to control microbial responses during the infection process and holds promise to provide an improved understanding of human health and disease on Earth.
Cheryl A Nickerson - One of the best experts on this subject based on the ideXlab platform.
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Efficacy of Antimicrobials on Bacteria Cultured in a Spaceflight Analogue
2014Co-Authors: Cheryl A Nickerson, Aurelie Crabbe, Jennifer Barrila, Richard R Davis, Virginia Wotring, Sarah L. Castro, April Rideout, Breanne MccarthyAbstract:As humans travel in space, they will interact with microbial flora from themselves, other crewmembers, their food, and the environment. While evaluations of microbial ecology aboard the Mir and ISS suggest a predominance of common environmental flora, the presence of (and potential for) infectious agents has been well documented. Likewise, pathogens have been detected during preflight monitoring of Spaceflight food, resulting in the disqualification of that production lot from flight. These environmental and food organisms range from the obligate pathogen, Salmonella enterica serovar Typhimurium (S. Typhimurium), which has been responsible for disqualification and removal of food destined for ISS and has previously been reported from Shuttle crew refuse, to the opportunistic pathogen Staphylococcus aureus, isolated numerous times from ISS habitable compartments and the crew. Infectious disease events have affected Spaceflight missions, including an upper respiratory infection that delayed the launch of STS-36 and an incapacitating Pseudomonas aeruginosa urinary tract infection of a crewmember during Apollo 13. These observations indicate that the crew has the potential to be exposed to obligate and opportunistic pathogens. This risk of exposure is expected to increase with longer mission durations and increased use of regenerative life support systems. As antibiotics are the primary countermeasure after infection, determining if their efficacy during Spaceflight missions is comparable to terrestrial application is of critical importance. The NASA Rotating Wall Vessel (RWV) culture system has been successfully used as a Spaceflight culture analogue to identify potential alterations in several key microbial characteristics, such as virulence and gene regulation, in response to Spaceflight culture. We hypothesized that bacteria cultured in the low fluid shear RWV environment would demonstrate changes in efficacy of antibiotics compared to higher fluid shear controls. This study investigated the response of three medically significant microorganisms grown in the RWV to antibiotics that could be used on Spaceflight missions. Our findings suggest potential alterations in antibiotic efficacy during Spaceflight and indicate that future studies on the antibiotic response require additional basic research using the RWV and/or true Spaceflight. However, while this analogue has reinforced these potential alterations, the results suggest the best approach for applied forward work is evaluating an in vivo system during Spaceflight, including human and rodent studies. The complex nature of the analysis for many antibiotics and organism suggests the best approach to determine in vivo responses during pharmaceutical treatment is evaluating an in vivo system during Spaceflight.
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transcriptional and proteomic responses of pseudomonas aeruginosa pao1 to Spaceflight conditions involve hfq regulation and reveal a role for oxygen
Applied and Environmental Microbiology, 2011Co-Authors: Aurelie Crabbe, Duane L Pierson, Michael J Schurr, Pieter Monsieurs, Lisa A Morici, Jill Schurr, James W Wilson, George Tsaprailis, Heidi Stefanyshynpiper, Cheryl A NickersonAbstract:Assessing bacterial behavior in microgravity is important for risk assessment and prevention of infectious diseases during Spaceflight missions. Furthermore, this research field allows the unveiling of novel connections between low-fluid-shear regions encountered by pathogens during their natural infection process and bacterial virulence. This study is the first to characterize the Spaceflight-induced global transcriptional and proteomic responses of Pseudomonas aeruginosa, an opportunistic pathogen that is present in the space habitat. P. aeruginosa responded to Spaceflight conditions through differential regulation of 167 genes and 28 proteins, with Hfq as a global transcriptional regulator. Since Hfq was also differentially regulated in Spaceflight-grown Salmonella enterica serovar Typhimurium, Hfq represents the first Spaceflight-induced regulator acting across bacterial species. The major P. aeruginosa virulence-related genes induced in Spaceflight were the lecA and lecB lectin genes and the gene for rhamnosyltransferase (rhlA), which is involved in rhamnolipid production. The transcriptional response of Spaceflight-grown P. aeruginosa was compared with our previous data for this organism grown in microgravity analogue conditions using the rotating wall vessel (RWV) bioreactor. Interesting similarities were observed, including, among others, similarities with regard to Hfq regulation and oxygen metabolism. While RWV-grown P. aeruginosa mainly induced genes involved in microaerophilic metabolism, P. aeruginosa cultured in Spaceflight presumably adopted an anaerobic mode of growth, in which denitrification was most prominent. Whether the observed changes in pathogenesis-related gene expression in response to Spaceflight culture could lead to an alteration of virulence in P. aeruginosa remains to be determined and will be important for infectious disease risk assessment and prevention, both during Spaceflight missions and for the general public.
