Modeling Calcium Loss from Bones During Space Flight

Calcium loss from bones during space flight creates a risk for astronauts who travel into space, and may prohibit space flights to other planets. The problem of calcium loss during space flight has been studied using animal models, bed rest (as a ground-based model), and humans in-flight. In-flight studies have typically documented bone loss by comparing bone mass before and after flight. To identify changes in metabolism leading to bone loss, we have performed kinetic studies using stable isotopes of calcium. Oral (Ca-43) and intravenous (Ca-46) tracers were administered to subjects (n=3), three-times before flight, once in-flight (after 110 days), and three times post-flight (on landing day, and 9 days and 3 months after flight). Samples of blood, saliva, urine, and feces were collected for up to 5 days after isotope administration, and were analyzed for tracer enrichment. Tracer data in tissues were analyzed using a compartmental model for calcium metabolism and the WinSAAM software. The model was used to: account for carryover of tracer between studies, fit data for all studies using the minimal number of changes between studies, and calculate calcium absorption, excretion, bone calcium deposition and bone calcium resorption. Results showed that fractional absorption decreased by 50% during flight and that bone resorption and urinary excretion increased by 50%. Results were supported by changes in biochemical markers of bone metabolism. Inflight bone loss of approximately 250 mg Ca/d resulted from decreased calcium absorption combined with increased bone resorption and excretion. Further studies will assess the time course of these changes during flight, and the effectiveness of countermeasures to mitigate flight-induced bone loss. The overall goal is to enable human travel beyond low-Earth orbit, and to allow for better understanding and treatment of bone diseases on Earth

Psychological and behavioral changes during confinement in a 520-day simulated interplanetary mission to mars.

Behavioral health risks are among the most serious and difficult to mitigate risks of confinement in space craft during long-duration space exploration missions. We report on behavioral and psychological reactions of a multinational crew of 6 healthy males confined in a 550 m(3) chamber for 520 days during the first Earth-based, high-fidelity simulated mission to Mars. Rest-activity of crewmembers was objectively measured throughout the mission with wrist-worn actigraphs. Once weekly throughout the mission crewmembers completed the Beck Depression Inventory-II (BDI-II), Profile of Moods State short form (POMS), conflict questionnaire, the Psychomotor Vigilance Test (PVT-B), and series of visual analogue scales on stress and fatigue. We observed substantial inter-individual differences in the behavioral responses of crewmembers to the prolonged mission confinement and isolation. The crewmember with the highest average POMS total mood disturbance score throughout the mission also reported symptoms of depression in 93% of mission weeks, which reached mild-to-moderate levels in >10% of mission weeks. Conflicts with mission control were reported five times more often than conflicts among crewmembers. Two crewmembers who had the highest ratings of stress and physical exhaustion accounted for 85% of the perceived conflicts. One of them developed a persistent sleep onset insomnia with ratings of poor sleep quality, which resulted in chronic partial sleep deprivation, elevated ratings of daytime tiredness, and frequent deficits in behavioral alertness. Sleep-wake timing was altered in two other crewmembers, beginning in the first few months of the mission and persisting throughout. Two crewmembers showed neither behavioral disturbances nor reports of psychological distress during the 17-month period of mission confinement. These results highlight the importance of identifying behavioral, psychological, and biological markers of characteristics that predispose prospective crewmembers to both effective and ineffective behavioral reactions during the confinement of prolonged spaceflight, to inform crew selection, training, and individualized countermeasures

Crew interactions were facilitated by a core group.

<p>During de-briefs, each crewmember was asked to report the two crewmembers interacted with most frequently during the mission. Arrows pointing to a crewmember indicate the number of times he was mentioned by others; those pointing away designate with whom he indicated he most often interacted. Circle size indicates the frequency with which a crewmember was identified as interacted with most frequently.</p

Perceived conflicts throughout the simulated Mars mission.

<p>The number of conflicts with mission control (left panel) and other crewmembers (middle panel) were counted for 30-day periods relative to a 30-day period surrounding the landing on Mars between mission days 244 and 273. One conflict was counted if the crewmember recorded either a current conflict and/or a conflict in the past seven days. Conflicts (reported once weekly) with mission control peaked during the Mars landing period, were lower in the second half compared to the first half of the mission (dashed lines represent averages over pre- and post-landing periods), and were reported more often than conflicts among crewmembers. The right panel shows the cumulative number of weeks with conflicts relative to time in mission by crewmember. The majority of conflicts were reported by crewmembers <i>e</i> and <i>f</i>.</p

Inter-individual differences in psychological measures.

<p><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0093298#pone-0093298-t002" target="_blank"><b>Table 2</b></a><b>:</b> Superscript letters a–f indicate a significant difference to the respective crewmember at α = 0.05 after Bonferroni correction for post-hoc tests. All scales were transformed to a 0 to 100 range. A score of 100 represents the maximal expression (e.g., maximal depression, maximal tension-anxiety, maximal unhappiness). Standard errors are reported in parenthesis. P-value for the main effect of crewmember is reported in the last column. POMS: Profile of Mood States Short Form; ICC: Intra-class Correlation;</p><p>* indicates that the respective crewmember answered 0 on all items throughout the whole mission.</p

Effects of time-in-mission on psychological measures.

<p><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0093298#pone-0093298-t001" target="_blank"><b>Table 1</b></a><b>:</b> Superscript number 1–4 indicate a significant difference to the respective mission quarter at α = 0.05 after Bonferroni correction of post-hoc tests. All scales were transformed to a 0 to 100 range. A score of 100 represents the maximal expression (e.g., maximal depression, maximal tension-anxiety, maximal unhappiness, etc.). Standard errors are reported in parenthesis. P-value for the main effect of mission quarter is reported in the last column. POMS: Profile of Mood States Short Form.</p

200+Protein Concentrations in Healthy Human Blood Plasma: Targeted Quantitative SRM SIS Screening of Chromosomes 18, 13, Y, and the Mitochondrial Chromosome Encoded Proteome

Mitochondria are undeniably the cell powerhouse, directly affecting cell survival and fate. Growing evidence suggest that mitochondrial protein repertoire affects metabolic activity and plays an important role in determining cell proliferation/differentiation or quiescence shift. Consequently, the bioenergetic status of a cell is associated with the quality and abundance of the mitochondrial populations and proteomes. Mitochondrial morphology changes in the development of different cellular functions associated with metabolic switches. It is therefore reasonable to speculate that different cell lines do contain different mitochondrialassociated proteins, and the investigation of these pools may well represent a source for mining missing proteins (MPs). A very effective approach to increase the number of IDs through mass spectrometry consists of reducing the complexity of the biological samples by fractionation. The present study aims at investigating the mitochondrial proteome of five phenotypically different cell lines, possibly expressing some of the MPs, through an enrichment 12fractionation approach at the organelle and protein level. We demonstrate a substantial increase in the proteome coverage, which, in turn, increases the likelihood of detecting low abundant proteins, often falling in the category of MPs, and resulting, for the present study, in the identification of METTL12, FAM163A, and RGS13. All MS data have been deposited to the MassIVE data repository (https://massive.ucsd. edu) with the data set identifier MSV000082409 and PXD010446

Crew relations forecasting based on WLGS data.

<p>The ARIMA model for forecasting of CRTI was based on data from mission day 15 to 470 (shown here beginning with day 461; for whole time series see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0134814#pone.0134814.s002" target="_blank">S1 File</a>). On day 470 the last deep minimum of CRTI occurs. The forecasting was verified with observed data of the predicted period mission day 470–515. For the predicted period predicted and observed values could be found in good accordance of for the next 3 to 4 days.</p

Comparison of two sensor’s data.

<p>Presence–absence detections between two sensors (crewmembers A and B) over one mission day registrations.</p