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https://www.readbyqxmd.com/read/28092926/effect-of-gravity-and-microgravity-on-intracranial-pressure
#1
Justin S Lawley, Lonnie G Petersen, Erin J Howden, Satyam Sarma, William K Cornwell, Rong Zhang, Louis A Whitworth, Michael A Williams, Benjamin D Levine
Astronauts have recently been discovered to have impaired vision, with a presentation that resembles syndromes of elevated intracranial pressure (ICP). This syndrome is considered the most mission critical medical problem identified in the past decade of manned spaceflight. We recruited five men and three women who had an Ommaya reservoir inserted for the delivery of prophylactic central nervous system chemotherapy, but were free of their malignant disease for at least 1 year. ICP was assessed by placing a fluid-filled 25 ga butterfly needle into the Ommaya reservoir...
January 16, 2017: Journal of Physiology
https://www.readbyqxmd.com/read/28087888/simulated-microgravity-decreases-circulating-iron-in-rats-role-of-inflammation-induced-hepcidin-upregulation
#2
Thibault Cavey, Nicolas Pierre, Kévin Nay, Coralie Allain, Martine Ropert, Olivier Loréal, Frédéric Derbré
During spaceflight, humans exposed to microgravity exhibit an increase of iron storage and a reduction of circulating iron. Such perturbations could promote oxidative stress and anemia in astronauts. The mechanism by which microgravity modulates iron metabolism is still unknown. Herein, we hypothesized that microgravity up-regulates hepcidin, a hormone produced by the liver that is the main controller of iron homeostasis. To test this hypothesis, rats were submitted to hindlimb unloading (HU), the reference model to mimic the effects of microgravity in rodents...
January 13, 2017: Experimental Physiology
https://www.readbyqxmd.com/read/28073867/the-maimed-martian-credible-intervals-and-bias-against-benefit
#3
David Kault
A sad little story about a maimed Martian astronaut is used to illustrate a method of improving confidence interval (CI) calculations. CIs in medical statistics are currently calculated from the data available in a clinical trial or meta-analysis considered in isolation from all other information available on earth. Likewise, the Martian in the story uses only information available to it, in isolation from further information from earth. However, there is further objective knowledge available to people on earth to improve the Martian's estimate...
January 10, 2017: Evidence-based Medicine
https://www.readbyqxmd.com/read/28068518/impact-of-space-environment-on-stability-of-medicines-challenges-and-prospects
#4
REVIEW
Priti Mehta, Dhara Bhayani
To upkeep health of astronauts in a unique, isolated, and extreme environment of space is the primary goal for a successful space mission, hence, safe and efficacious medications are essential for the wellness of astronauts. Space medication has been challenged with problems related to efficacy. Along with altered physiology, one of the possible reasons could be instability of space medications in the presence of harsh spaceflight environmental conditions. Altered physical and chemical stability can result in reduced potency which can result in reduced efficacy...
January 3, 2017: Journal of Pharmaceutical and Biomedical Analysis
https://www.readbyqxmd.com/read/28061916/intracranial-and-intraocular-pressure-during-various-degrees-of-head-down-tilt
#5
Karina Marshall-Goebel, Edwin Mulder, Eric Bershad, Charles Laing, Anders Eklund, Jan Malm, Claudia Stern, Jörn Rittweger
BACKGROUND: More than half of astronauts develop ophthalmic changes during long-duration spaceflight consistent with an abnormal intraocular and intracranial pressure (IOP, ICP) difference. The aim of our study was to assess IOP and ICP during head-down tilt (HDT) and the additive or attenuating effects of 1% CO2 and lower body negative pressure (LBNP). METHODS: In Experiment I, IOP and ICP were measured in nine healthy subjects after 3.5 h HDT in five conditions: -6°, -12°, and -18° HDT, -12° with 1% CO2, and -12° with -20 mmHg LBNP...
January 1, 2017: Aerospace Medicine and Human Performance
https://www.readbyqxmd.com/read/28050606/long-term-exposure-to-space-s-microgravity-alters-the-time-structure-of-heart-rate-variability-of-astronauts
#6
Kuniaki Otsuka, Germaine Cornelissen, Satoshi Furukawa, Yutaka Kubo, Mitsutoshi Hayashi, Koichi Shibata, Koh Mizuno, Tatsuya Aiba, Hiroshi Ohshima, Chiaki Mukai
BACKGROUND: Spaceflight alters human cardiovascular dynamics. The less negative slope of the fractal scaling of heart rate variability (HRV) of astronauts exposed long-term to microgravity reflects cardiovascular deconditioning. We here focus on specific frequency regions of HRV. METHODS: Ten healthy astronauts (8 men, 49.1 ± 4.2 years) provided five 24-hour electrocardiographic (ECG) records: before launch, 20.8 ± 2.9 (ISS01), 72.5 ± 3.9 (ISS02) and 152.8 ± 16...
December 2016: Heliyon
https://www.readbyqxmd.com/read/28039409/internal-jugular-pressure-increases-during-parabolic-flight
#7
David S Martin, Stuart M C Lee, Timothy P Matz, Christian M Westby, Jessica M Scott, Michael B Stenger, Steven H Platts
One hypothesized contributor to vision changes experienced by >75% of International Space Station astronauts is elevated intracranial pressure (ICP). While no definitive data yet exist, elevated ICP might be secondary to the microgravity-induced cephalad fluid shift, resulting in venous congestion (overfilling and distension) and inhibition of cerebrospinal and lymphatic fluid drainage from the skull. The objective of this study was to measure internal jugular venous pressure (IJVP) during normo- and hypo-gravity as an index of venous congestion...
December 2016: Physiological Reports
https://www.readbyqxmd.com/read/28027021/whole-body-movements-in-long-term-weightlessness-hierarchies-of-the-controlled-variables-are-gravity-dependent
#8
Claudia Casellato, Alessandra Pedrocchi, Giancarlo Ferrigno
Switching between contexts affects the mechanisms underlying motion planning, in particular it may entail reranking the variables to be controlled in defining the motor solutions. Three astronauts performed multiple sessions of whole-body pointing, in normogravity before launch, in prolonged weightlessness onboard the International Space Station, and after return. The effect of gravity context on kinematic and dynamic components was evaluated. Hand trajectory was gravity independent; center-of-mass excursion was highly variable within and between subjects...
December 27, 2016: Journal of Motor Behavior
https://www.readbyqxmd.com/read/28001909/neudose-a-cubesat-mission-for-dosimetry-of-charged-particles-and-neutrons-in-low-earth-orbit
#9
A R Hanu, J Barberiz, D Bonneville, S H Byun, L Chen, C Ciambella, E Dao, V Deshpande, R Garnett, S D Hunter, A Jhirad, E M Johnston, M Kordic, M Kurnell, L Lopera, M McFadden, A Melnichuk, J Nguyen, A Otto, R Scott, D L Wagner, M Wiendels
During space missions, astronauts are exposed to a stream of energetic and highly ionizing radiation particles that can suppress immune system function, increase cancer risks and even induce acute radiation syndrome if the exposure is large enough. As human exploration goals shift from missions in low-Earth orbit (LEO) to long-duration interplanetary missions, radiation protection remains one of the key technological issues that must be resolved. In this work, we introduce the NEUtron DOSimetry & Exploration (NEUDOSE) CubeSat mission, which will provide new measurements of dose and space radiation quality factors to improve the accuracy of cancer risk projections for current and future space missions...
December 21, 2016: Radiation Research
https://www.readbyqxmd.com/read/27994557/intervertebral-disc-swelling-demonstrated-by-3d-and-water-content-magnetic-resonance-analyses-after-a-3-day-dry-immersion-simulating-microgravity
#10
Loïc Treffel, Karen Mkhitaryan, Stéphane Gellee, Guillemette Gauquelin-Koch, Claude Gharib, Stéphane Blanc, Catherine Millet
Background: Vertebral deconditioning is commonly experienced after space flight and simulation studies. Disc herniation is quadrupled after space flight. Purpose: The main hypothesis formulated by the authors is that microgravity results in intervertebral disc (IVD) swelling. Study Design: The aim of the study was to identify the morphological changes of the spine and their clinical consequences after simulated microgravity by 3-day dry immersion (DI). The experimental protocol was performed on 12 male volunteers using magnetic resonance imaging and spectroscopy before and after DI...
2016: Frontiers in Physiology
https://www.readbyqxmd.com/read/27982062/changes-in-mitochondrial-homeostasis-and-redox-status-in-astronauts-following-long-stays-in-space
#11
Hiroko P Indo, Hideyuki J Majima, Masahiro Terada, Shigeaki Suenaga, Kazuo Tomita, Shin Yamada, Akira Higashibata, Noriaki Ishioka, Takuro Kanekura, Ikuya Nonaka, Clare L Hawkins, Michael J Davies, Daret K St Clair, Chiaki Mukai
The effects of long-term exposure to extreme space conditions on astronauts were investigated by analyzing hair samples from ten astronauts who had spent six months on the International Space Station (ISS). Two samples were collected before, during and after their stays in the ISS; hereafter, referred to as Preflight, Inflight and Postflight, respectively. The ratios of mitochondrial (mt) to nuclear (n) DNA and mtRNA to nRNA were analyzed via quantitative PCR. The combined data of Preflight, Inflight and Postflight show a significant reduction in the mtDNA/nDNA in Inflight, and significant reductions in the mtRNA/nRNA ratios in both the Inflight and Postflight samples...
December 16, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27930421/persistent-asymmetric-optic-disc-swelling-after-long-duration-space-flight-implications-for-pathogenesis
#12
Thomas H Mader, C Robert Gibson, Christian A Otto, Ashot E Sargsyan, Neil R Miller, Prem S Subramanian, Stephen F Hart, William Lipsky, Nimesh B Patel, Andrew G Lee
BACKGROUND: Several ophthalmic findings including optic disc swelling, globe flattening and choroidal folds have been observed in astronauts following long-duration space flight. The authors now report asymmetric choroidal expansion, disc swelling and optic disc morphologic changes in a 45-year-old astronaut which occurred during long-duration space flight and persisted following his space mission. METHODS: Case study of ocular findings in an astronaut documented during and after a long-duration space flight of approximately 6 months...
December 5, 2016: Journal of Neuro-ophthalmology: the Official Journal of the North American Neuro-Ophthalmology Society
https://www.readbyqxmd.com/read/27925861/modeling-heavy-ion-impairment-of-hippocampal-neurogenesis-after-acute-and-fractionated-irradiation
#13
Eliedonna Cacao, Francis A Cucinotta
Radiation-induced impairment of neurogenesis in the hippocampal dentate gyrus is a concern due to its reported association with cognitive detriments after radiotherapy for brain cancers and the possible risks to astronauts chronically exposed to space radiation. Here, we have extended our recent work in a mouse model of impaired neurogenesis after exposure to low-linear energy transfer (LET) radiation to heavy ion irradiation. To our knowledge, this is the first report of a predictive mathematical model of radiation-induced changes to neurogenesis for a variety of radiation types after acute or fractionated irradiation...
December 2016: Radiation Research
https://www.readbyqxmd.com/read/27920669/the-neurovestibular-challenges-of-astronauts-and-balance-patients-some-past-countermeasures-and-two-alternative-approaches-to-elicitation-assessment-and-mitigation
#14
REVIEW
Ben D Lawson, Angus H Rupert, Braden J McGrath
Astronauts and vestibular patients face analogous challenges to orientation function due to adaptive exogenous (weightlessness-induced) or endogenous (pathology-induced) alterations in the processing of acceleration stimuli. Given some neurovestibular similarities between these challenges, both affected groups may benefit from shared research approaches and adaptation measurement/improvement strategies. This article reviews various past strategies and introduces two plausible ground-based approaches, the first of which is a method for eliciting and assessing vestibular adaptation-induced imbalance...
2016: Frontiers in Systems Neuroscience
https://www.readbyqxmd.com/read/27919335/cataractogenesis-following-high-let-radiation-exposure
#15
Nobuyuki Hamada, Tatsuhiko Sato
Biological effectiveness of ionizing radiation differs with its linear energy transfer (LET) such that high-LET radiation is more effective for various biological endpoints than low-LET radiation. Human exposure to high-LET radiation occurs in cancer patients, nuclear workers, aviators, astronauts and other space travellers. From the radiation protection viewpoint, the ocular lens is among the most radiosensitive tissues in the body, and cataract (a clouding of the normally transparent lens) is classified as tissue reactions (formerly called nonstochastic or deterministic effects) with a threshold below which no effect would occur...
October 2016: Mutation Research
https://www.readbyqxmd.com/read/27907194/preservation-of-multiple-mammalian-tissues-to-maximize-science-return-from-ground-based-and-spaceflight-experiments
#16
Sungshin Choi, Hami E Ray, San-Huei Lai, Joshua S Alwood, Ruth K Globus
BACKGROUND: Even with recent scientific advancements, challenges posed by limited resources and capabilities at the time of sample dissection continue to limit the collection of high quality tissues from experiments that can be conducted only infrequently and at high cost, such as in space. The resources and time it takes to harvest tissues post-euthanasia, and the methods and duration of long duration storage, potentially have negative impacts on sample quantity and quality, thereby limiting the scientific outcome that can be achieved...
2016: PloS One
https://www.readbyqxmd.com/read/27883068/-cerebellar-contribution-to-visuo-attentional-alpha-rhythm-insights-from-weightlessness
#17
A M Cebolla, M Petieau, B Dan, L Balazs, J McIntyre, G Cheron
Human brain adaptation in weightlessness follows the necessity to reshape the dynamic integration of the neural information acquired in the new environment. This basic aspect was here studied by the electroencephalogram (EEG) dynamics where oscillatory modulations were measured during a visuo-attentional state preceding a visuo-motor docking task. Astronauts in microgravity conducted the experiment in free-floating aboard the International Space Station, before the space flight and afterwards. We observed stronger power decrease (~ERD: event related desynchronization) of the ~10 Hz oscillation from the occipital-parietal (alpha ERD) to the central areas (mu ERD)...
November 24, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27881872/in-vitro-and-in-vivo-assessment-of-direct-effects-of-simulated-solar-and-galactic-cosmic-radiation-on-human-hematopoietic-stem-progenitor-cells
#18
C Rodman, G Almeida-Porada, S K George, J Moon, S Soker, T Pardee, M Beaty, P Guida, S P Sajuthi, C D Langefeld, S J Walker, P F Wilson, C D Porada
Future deep space missions to Mars and near-Earth asteroids will expose astronauts to chronic solar energetic particles (SEP) and galactic cosmic ray (GCR) radiation, and likely one or more solar particle events (SPEs). Given the inherent radiosensitivity of hematopoietic cells and short latency period of leukemias, space radiation-induced hematopoietic damage poses a particular threat to astronauts on extended missions. We show that exposing human hematopoietic stem/progenitor cells (HSC) to extended mission-relevant doses of accelerated high-energy protons and iron ions leads to the following: (1) introduces mutations that are frequently located within genes involved in hematopoiesis and are distinct from those induced by γ-radiation; (2) markedly reduces in vitro colony formation; (3) markedly alters engraftment and lineage commitment in vivo; and (4) leads to the development, in vivo, of what appears to be T-ALL...
December 9, 2016: Leukemia: Official Journal of the Leukemia Society of America, Leukemia Research Fund, U.K
https://www.readbyqxmd.com/read/27876887/high-energy-particle-radiation-associated-oncogenic-transformation-in-normal-mice-insight-into-the-connection-between-activation-of-oncotargets-and-oncogene-addiction
#19
Natarajan Aravindan, Sheeja Aravindan, Krishnan Manickam, Mohan Natarajan
Concerns on high-energy particle radiation-induced tumorigenic transformation of normal tissue in astronauts, and in cancer patients undergoing radiotherapy, emphasizes the significance of elucidating the mechanisms involved in radiogenic transformation processes. Mostly used genetically modified or tumor-prone models are less reliable in determining human health risk in space or protracted post-treatment normal tissue toxicity. Here, in wild type C57BL/6 mice, we related the deregulation of distinctive set of tissue-specific oncotargets in major organs upon (56)Fe (600 MeV/amu; 0...
November 23, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27865670/radiation-damage-to-neuronal-cells-simulating-the-energy-deposition-and-water-radiolysis-in-a-small-neural-network
#20
Oleg V Belov, Munkhbaatar Batmunkh, Sébastien Incerti, Oidov Lkhagva
Radiation damage to the central nervous system (CNS) has been an on-going challenge for the last decades primarily due to the issues of brain radiotherapy and radiation protection for astronauts during space travel. Although recent findings revealed a number of molecular mechanisms associated with radiation-induced impairments in behaviour and cognition, some uncertainties exist in the initial neuronal cell injury leading to the further development of CNS malfunction. The present study is focused on the investigation of early biological damage induced by ionizing radiations in a sample neural network by means of modelling physico-chemical processes occurring in the medium after exposure...
December 2016: Physica Medica: PM
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