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Christian Otto - One of the best experts on this subject based on the ideXlab platform.
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optical coherence tomography analysis of the optic nerve head and surrounding structures in long duration international space station Astronauts
JAMA Ophthalmology, 2018Co-Authors: Nimesh B Patel, Charles Robert Gibson, Anastas Pass, Sara Mason, Christian OttoAbstract:Importance After long-duration spaceflight, morphological changes in the optic nerve head (ONH) and surrounding tissues have been reported. Objective To develop methods to quantify ONH and surrounding tissue changes using preflight and postflight optical coherence tomographic scans of the ONH region. Design, Setting, and Participants Two separate analyses were done on retrospective data, with the first comparing a preflight group with a control group, followed by preflight to postflight analysis. All astronaut data were collected on the same instrument and maintained by the National Aeronautics and Space Administration (NASA) Lifetime Surveillance of Astronaut Health. Control data were all collected at the University of Houston. Participants were 15 Astronauts who had previously been on an approximately 6-month long-duration mission and had associated preflight and postflight ONH scans. The control group consisted of 43 individuals with no history of ocular pathology or microgravity exposure. Development of algorithms and data analysis were performed between 2012 and 2015. Main Outcomes and Measures The optical coherence tomography data were analyzed using custom MATLAB programs (MathWorks) in which the Bruch membrane opening (BMO) was manually delineated and used as a reference for all morphological measures. The retinal pigment epithelium (RPE) position 2 mm from the center of the BMO was used to calculate the BMO height. Global and quadrant total retinal thickness and retinal nerve fiber layer (RNFL) thickness were calculated for elliptical annular regions referenced to the BMO. The standard circumpapillary circular scan was used to quantify RNFL and choroidal thickness. Results Among 15 Astronauts (mean [SD] age at preflight evaluation, 48.7 [4.0] years) in this retrospective study, the BMO was recessed in preflight Astronauts compared with healthy controls and deepened after long-duration microgravity exposure (median change, −9.9 μm; 95% CI of difference, −16.3 to 3.7 μm; P = .03). After long-duration missions, there was an increase in total retinal thickness to 1000 μm and RNFL to 500 μm from the BMO. Circumpapillary RNFL thickness increased by a median of 2.9 μm (95% CI of difference, 1.1-4.4 μm; P P = .66). Conclusions and Relevance After long-duration microgravity exposure, there are disc edema–like changes in the morphology of the ONH and surrounding tissue. The methods developed to analyze the ONH and surrounding tissue can be useful for assessing longitudinal changes and countermeasures in Astronauts, as well as potentially for terrestrial disc edema causes.
Jeffrey A Jones - One of the best experts on this subject based on the ideXlab platform.
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Renal stone formation among Astronauts.
Aviation Space and Environmental Medicine, 2007Co-Authors: Robert A Pietrzyk, Jeffrey A Jones, Clarence F Sams, Peggy A WhitsonAbstract:Introduction: With the continued construction of the International Space Station, humans are living longer in the microgravity environment of space. However, many questions still exist as to the physiological effects of spaceflight on the human body. Bone loss, cardiovascular changes, and muscle atrophy are well-documented health risks to humans during spaceflight. Another potential serious health complication is the development of renal stones. The development of a renal stone may not only impact the health of the crewmember, but also the success of the mission. Methods: A retrospective analysis of astronaut data from 24-h urine samples collected prior to launch and immediately after landing was performed. Urine characteristics associated with renal stone formation were analyzed and the relative injury supersaturations of stone-forming constituents calculated. Results: In the current study, previously collected data to identify urinary factors associated with renal stone formation demonstrated an increased risk in Astronauts who had actually formed a renal stone. Increased urinary supersaturation of the stone-forming salts was observed in those Astronauts who formed renal stones. Similar changes in urinary supersaturation were noted among many Astronauts after landing, indicating an increased postflight risk for stone formation. Conclusions: An assessment program should be undertaken to identify and evaluate Astronauts with elevated risk factors prior to flight and immediately following landing. Individualized recommendations can be prescribed to Astronauts and may include dietary changes, increased fluid intake, or medications to minimize the risk of stone formation.
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Acute urinary retention among Astronauts.
Aviation Space and Environmental Medicine, 2007Co-Authors: Philip C Stepaniak, Suneil R Ramchandani, Jeffrey A JonesAbstract:Although acute urinary retention (AUR) is not commonly thought of as a life-threatening condition, its presentation in orbit can lead to a number of medical complications that could compromise a space mission. We report on a middle-aged astronaut who developed urinary retention during two spaceflights. On the first mission of note, the astronaut initially took standard doses of promethazine and scopolamine before launch, and developed AUR immediately after entering orbit. For the first 3 d, the astronaut underwent intermittent catheterizations with a single balloon-tipped catheter. Due to the lack of iodine solution on board and the need for the astronaut to complete certain duties without interruption, the catheter was left in place for a total of 4 d. Although the ability to void returned after day 7, a bout of AUR reemerged on day 10, 1 d before landing. On return to Earth, a cystometrogram was unremarkable. During the astronaut's next mission, AUR again recurred for the first 24 h of microgravity exposure, and the astronaut was subsequently able to void spontaneously while in space. This report details the presentation of this astronaut, the precautions that were taken for space travel subsequent to the initial episode of AUR, and the possible reasons why space travel can predispose Astronauts to urinary retention while in orbit. The four major causes of AUR-obstructive, pharmacologic, psychogenic, and neurogenic-are discussed, with an emphasis on how these may have played a role in this case. agement guidelines and onboard supplies that resulted from the lessons learned in this case.
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Acute urinary retention among Astronauts.
Aviation space and environmental medicine, 2007Co-Authors: Philip C Stepaniak, Suneil R Ramchandani, Jeffrey A JonesAbstract:Although acute urinary retention (AUR) is not commonly thought of as a life-threatening condition, its presentation in orbit can lead to a number of medical complications that could compromise a space mission. We report on a middle-aged astronaut who developed urinary retention during two spaceflights. On the first mission of note, the astronaut initially took standard doses of promethazine and scopolamine before launch, and developed AUR immediately after entering orbit. For the first 3 d, the astronaut underwent intermittent catheterizations with a single balloon-tipped catheter. Due to the lack of iodine solution on board and the need for the astronaut to complete certain duties without interruption, the catheter was left in place for a total of 4 d. Although the ability to void returned after day 7, a bout of AUR reemerged on day 10, 1 d before landing. On return to Earth, a cystometrogram was unremarkable. During the astronaut's next mission, AUR again recurred for the first 24 h of microgravity exposure, and the astronaut was subsequently able to void spontaneously while in space. This report details the presentation of this astronaut, the precautions that were taken for space travel subsequent to the initial episode of AUR, and the possible reasons why space travel can predispose Astronauts to urinary retention while in orbit. The four major causes of AUR--obstructive, pharmacologic, psychogenic, and neurogenic-are discussed, with an emphasis on how these may have played a role in this case.
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space radiation and cataracts in Astronauts
Radiation Research, 2001Co-Authors: Francis A Cucinotta, Jeffrey A Jones, F K Manuel, G Iszard, J Murrey, B Djojonegro, Mary L. WearAbstract:For over 30 years, Astronauts in Earth orbit or on missions to the moon have been exposed to space radiation comprised of high-energy protons and heavy ions and secondary particles produced in collisions with spacecraft and tissue. Large uncertainties exist in the projection of risks of late effects from space radiation such as cancer and cataracts due to the paucity [corrected] of epidemiological data. Here we present epidemiological [corrected] data linking an increased risk of cataracts for Astronauts with higher lens doses (>8 mSv) of space radiation relative to other Astronauts with lower lens doses (<8 mSv). Our study uses historical data for cataract incidence in the 295 Astronauts participating in NASA's Longitudinal Study of Astronaut Health (LSAH) and individual occupational radiation exposure data. These results, while preliminary because of the use of subjective scoring methods, suggest that relatively low doses of space radiation may predispose crew to [corrected] an increased incidence and early appearance of cataracts.
Mary L. Wear - One of the best experts on this subject based on the ideXlab platform.
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Protecting the Health of Astronauts: Enhancing Occupational Health Monitoring and Surveillance for Former NASA Astronauts to Understand Long-Term Outcomes of Spaceflight-Related Exposures
World Academy of Science Engineering and Technology International Journal of Medical and Health Sciences, 2017Co-Authors: Meredith Rossi, Mary Van Baalen, Lesley R. Lee, Mary L. Wear, Bradley RhodesAbstract:The astronaut community is unique, and may be disproportionately exposed to occupational hazards not commonly seen in other communities. The extent to which the demands of the astronaut occupation and exposure to spaceflight-related hazards affect the health of the astronaut population over the life course is not completely known. A better understanding of the individual, population, and mission impacts of astronaut occupational exposures is critical to providing clinical care, targeting occupational surveillance efforts, and planning for future space exploration. The ability to characterize the risk of latent health conditions is a significant component of this understanding. Provision of health screening services to active and former Astronauts ensures individual, mission, and community health and safety. Currently, the NASA-Johnson Space Center (JSC) Flight Medicine Clinic (FMC) provides extensive medical monitoring to active Astronauts throughout their careers. Upon retirement, Astronauts may voluntarily return to the JSC FMC for an annual preventive exam. However, current retiree monitoring includes only selected screening tests, representing an opportunity for augmentation. The potential long-term health effects of spaceflight demand an expanded framework of testing for former Astronauts. The need is two-fold: screening tests widely recommended for other aging populations are necessary to rule out conditions resulting from the natural aging process (e.g., colonoscopy, mammography); and expanded monitoring will increase NASA's ability to better characterize conditions resulting from astronaut occupational exposures. To meet this need, NASA has begun an extensive exploration of the overall approach, cost, and policy implications of e an Astronaut Occupational Health program to include expanded medical monitoring of former NASA Astronauts. Increasing the breadth of monitoring services will ultimately enrich the existing evidence base of occupational health risks to Astronauts. Such an expansion would therefore improve the understanding of the health of the astronaut population as a whole, and the ability to identify, mitigate, and manage such risks in preparation for deep space exploration missions.
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Safeguarding the Health of the NASA Astronaut Community: the Need for Expanded Medical Monitoring for Former NASA Astronauts Under the Astronaut Occupational Health Program
2016Co-Authors: Bradley Rhodes, Lesley R. Lee, Mary Van Baalen, Meredith Rossi, Mary L. WearAbstract:The astronaut community is unique, and may be disproportionately exposed to occupational hazards not commonly seen in other communities. The extent to which the demands of the astronaut occupation and exposure to spaceflight-related hazards affect the health of the astronaut population over the life course is not completely known. Provision of health screening services to active and former Astronauts ensures individual, mission, and community health and safety. Currently, the NASA Johnson Space Center (JSC) Flight Medicine Clinic (FMC) provides extensive medical monitoring to active Astronauts throughout their careers. Upon retirement, Astronauts may voluntarily return to the JSC FMC for an annual preventive exam. However, current retiree monitoring includes only selected screening tests, representing an opportunity for augmentation. The potential latent health effects of spaceflight demand an expanded framework of testing for former Astronauts. The need is two-fold: screening tests widely recommended for other aging communities are necessary for Astronauts to rule out conditions resulting from the natural aging process (e.g., colonoscopy, mammography), as opposed to conditions resulting directly from the astronaut occupation; and increased breadth of monitoring services will improve the understanding of occupational health risks and longitudinal health of the astronaut community, past, present, and future. To meet this need, NASA has begun an extensive exploration of the overall approach, cost, and policy implications of expanding existing medical monitoring under the Astronaut Occupational Health program for former NASA Astronauts.
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space radiation and cataracts in Astronauts
Radiation Research, 2001Co-Authors: Francis A Cucinotta, Jeffrey A Jones, F K Manuel, G Iszard, J Murrey, B Djojonegro, Mary L. WearAbstract:For over 30 years, Astronauts in Earth orbit or on missions to the moon have been exposed to space radiation comprised of high-energy protons and heavy ions and secondary particles produced in collisions with spacecraft and tissue. Large uncertainties exist in the projection of risks of late effects from space radiation such as cancer and cataracts due to the paucity [corrected] of epidemiological data. Here we present epidemiological [corrected] data linking an increased risk of cataracts for Astronauts with higher lens doses (>8 mSv) of space radiation relative to other Astronauts with lower lens doses (<8 mSv). Our study uses historical data for cataract incidence in the 295 Astronauts participating in NASA's Longitudinal Study of Astronaut Health (LSAH) and individual occupational radiation exposure data. These results, while preliminary because of the use of subjective scoring methods, suggest that relatively low doses of space radiation may predispose crew to [corrected] an increased incidence and early appearance of cataracts.
Peter Paul De Deyn - One of the best experts on this subject based on the ideXlab platform.
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intracranial pressure induced optic nerve sheath response as a predictive biomarker for optic disc edema in Astronauts
Biomarkers in Medicine, 2017Co-Authors: Peter Wostyn, Peter Paul De DeynAbstract:A significant proportion of the Astronauts who spend extended periods in microgravity develop ophthalmic abnormalities. Understanding this syndrome, called visual impairment and intracranial pressure (VIIP), has become a high priority for National Aeronautics and Space Administration, especially in view of future long-duration missions (e.g., Mars missions). Moreover, to ensure selection of astronaut candidates who will be able to complete long-duration missions with low risk of the VIIP syndrome, it is imperative to identify biomarkers for VIIP risk prediction. Here, we hypothesize that the optic nerve sheath response to alterations in intracranial pressure may be a potential predictive biomarker for optic disc edema in Astronauts. If confirmed, this biomarker could be used for preflight identification of Astronauts at risk for developing VIIP-associated optic disc edema.
Duane L. Pierson - One of the best experts on this subject based on the ideXlab platform.
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latent virus reactivation in Astronauts on the international space station
NPJ microgravity, 2017Co-Authors: Satish K Mehta, Alan H. Feiveson, Mark L Laudenslager, Raymond P Stowe, Brian E Crucian, Clarence Sams, Duane L. PiersonAbstract:Reactivation of latent herpes viruses was measured in 23 Astronauts (18 male and 5 female) before, during, and after long-duration (up to 180 days) spaceflight onboard the international space station . Twenty age-matched and sex-matched healthy ground-based subjects were included as a control group. Blood, urine, and saliva samples were collected before, during, and after spaceflight. Saliva was analyzed for Epstein–Barr virus, varicella-zoster virus, and herpes simplex virus type 1. Urine was analyzed for cytomegalovirus. One astronaut did not shed any targeted virus in samples collected during the three mission phases. Shedding of Epstein–Barr virus, varicella-zoster virus, and cytomegalovirus was detected in 8 of the 23 Astronauts. These viruses reactivated independently of each other. Reactivation of Epstein–Barr virus, varicella-zoster virus, and cytomegalovirus increased in frequency, duration, and amplitude (viral copy numbers) when compared to short duration (10 to 16 days) space shuttle missions. No evidence of reactivation of herpes simplex virus type 1, herpes simplex virus type 2, or human herpes virus 6 was found. The mean diurnal trajectory of salivary cortisol changed significantly during flight as compared to before flight (P = 0.010). There was no statistically significant difference in levels of plasma cortisol or dehydoepiandosterone concentrations among time points before, during, and after flight for these international space station crew members, although observed cortisol levels were lower at the mid and late-flight time points. The data confirm that Astronauts undertaking long-duration spaceflight experience both increased latent viral reactivation and changes in diurnal trajectory of salivary cortisol concentrations.
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Changes in monocyte functions of Astronauts.
Brain behavior and immunity, 2005Co-Authors: Indreshpal Kaur, Elizabeth R. Simons, Victoria A. Castro, C. Mark Ott, Duane L. PiersonAbstract:Abstract As part of the systematic evaluation of the innate immune system for long duration missions, this study focused on the antimicrobial functions of monocytes in Astronauts participating in spaceflight. The study included four space shuttle missions and 25 Astronauts. Nine non-Astronauts served as controls. Blood specimens were collected 10 days before launch, within 3 h after landing, and again 3 days after landing. The number of monocytes did not differ significantly over the interval sampled in both the astronaut or control groups. However, following 5–11 days of spaceflight, the Astronauts’ monocytes exhibited reductions in ability to engulf Escherichia coli , elicit an oxidative burst, and degranulate. The phagocytic index was significantly reduced following spaceflight when compared to control values. This reduction in phagocytosis was accompanied by changes in the expression of two surface markers involved in phagocytosis, CD32 and CD64. Levels of cortisol, epinephrine, and norepinephrine after spaceflight did not increase over preflight values.
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stress induced subclinical reactivation of varicella zoster virus in Astronauts
Journal of Medical Virology, 2004Co-Authors: Satish K Mehta, Randall J Cohrs, Bagher Forghani, Gary O Zerbe, Donald H Gilden, Duane L. PiersonAbstract:Varicella zoster virus (VZV) becomes latent in human ganglia after primary infection. VZV reactivation occurs primarily in elderly individuals, organ transplant recipients, and patients with cancer and AIDS, correlating with a specific decline in cell-mediated immunity to the virus. VZV can also reactivate after surgical stress. The unexpected occurrence of thoracic zoster 2 days before space flight in a 47-year-old healthy astronaut from a pool of 81 physically fit Astronauts prompted our search for VZV reactivation during times of stress to determine whether VZV can also reactivate after non-surgical stress. We examined total DNA extracted from 312 saliva samples of eight Astronauts before, during, and after space flight for VZV DNA by polymerase chain reaction: 112 samples were obtained 234-265 days before flight, 84 samples on days 2 through 13 of space flight, and 116 samples on days 1 through 15 after flight. Before space flight, only one of the 112 saliva samples from a single astronaut was positive for VZV DNA. In contrast, during and after space flight, 61 of 200 (30%) saliva samples were positive in all eight Astronauts. No VZV DNA was detected in any of 88 saliva samples from 10 healthy control subjects. These results indicate that VZV can reactivate subclinically in healthy individuals after non-surgical stress.
