Evidence indicates that cerebral blood flow is both increased and diminished in astronauts on return to Earth. Data from ground-based animal models simulating the effects of microgravity have shown that decrements in cerebral perfusion are associated with enhanced vasoconstriction and structural remodeling of cerebral arteries. Based on these results, the purpose of this study was to test the hypothesis that 13 d of spaceflight [Space Transportation System (STS)-135 shuttle mission] enhances myogenic vasoconstriction, increases medial wall thickness, and elicits no change in the mechanical properties of mouse cerebral arteries. Basilar and posterior communicating arteries (PCAs) were isolated from 9-wk-old female C57BL/6 mice for in vitro vascular and mechanical testing. Contrary to that hypothesized, myogenic vasoconstrictor responses were lower and vascular distensibility greater in arteries from spaceflight group (SF) mice (n=7) relative to ground-based control group (GC) mice (n=12). Basilar artery maximal diameter was greater in SF mice (SF: 236+/-9 mum and GC: 215+/-5 mum) with no difference in medial wall thickness (SF: 12.4+/-1.6 mum; GC: 12.2+/-1.2 mum). Stiffness of the PCA, as characterized via nanoindentation, was lower in SF mice (SF: 3.4+/-0.3 N/m; GC: 5.4+/-0.8 N/m). Collectively, spaceflight-induced reductions in myogenic vasoconstriction and stiffness and increases in maximal diameter of cerebral arteries signify that elevations in brain blood flow may occur during spaceflight. Such changes in cerebral vascular control of perfusion could contribute to increases in intracranial pressure and an associated impairment of visual acuity in astronauts during spaceflight.
Research Containing: Humans
The probability that a dose of ionizing radiation kills a cell is about 10,000 times the probability that the cell will be transformed to malignancy. On the other hand, the number of cells killed required to significantly impact health is about 10,000 times the number that must be transformed to cause a late malignancy. If these two risks, cell killing and malignant transformation, are about equal, then the risk that occurs during a mission is more significant than the risk that occurs after a mission. The latent period for acute irradiation effects (cell killing) is about 2-4 weeks; the latent period for malignancy is 10-20 years. If these statements are approximately true, then the impact of cell killing on health in the low-gravity environment of space flight should be examined to establish an estimate of risk. The objective of this study is to synthesize data and conclusions from three areas of space biology and environmental health to arrive at rational risk assessment for radiations received by spacecraft crews: (1) the increased physiological demands of the space flight environment; (2) the effects of the space flight environment on physiological systems; and (3) the effects of radiation on physiological systems. One physiological system has been chosen: the immune response and its components, consisting of myeloid and lymphoid proliferative cell compartments. Best-case and worst-case scenarios are considered. In the worst case, a doubling of immune-function demand, accompanied by a halving of immune capacity, would reduce the endangering dose to a crew member to around 1 Gy.
Astronauts often show skin reactions in space. Systematic tests, e.g. with noninvasive skin physiological test methods, have not yet been done. In an interdisciplinary cooperation, a test series with skin physiological measurements was carried out before, during and after a long-term mission in the International Space Station. The hydration of the stratum corneum (Corneometer), transepidermal water loss (Tewameter), and the surface structure of the skin (SkinVisiometer) were measured. In order to record cutaneous states, the suction elasticity was measured (Cutometer), and an ultrasound measurement with 20 MHz (DermaScan) was also made. In addition, one measuring field of the two inner forearms was treated with a skin care emulsion. There were indications of a delayed epidermal proliferation of the cells, which would correspond to the clinical symptoms. Hydration and TEWL values are improved by respective skin care. On the cutaneous level, the elasticity measurements and the ultrasound picture showed results which correspond to a significant loss of elasticity of the skin. Further examinations are necessary to validate these preliminary results.
Some of the aspects of comparative analysis of the hemodynamic reactions to LBNP in cosmonauts of different age groups
This was the first study of age-related differences of the cardiovascular system functioning and reactions to the LBNP test in career cosmonauts. Results of 174 LBNP tests performed within the standard medical monitoring program using Gamma-01 (orbital station Mir) and Gamma-lM (ISS) were subjected to comparative analysis. Thirty eight cosmonauts–members of 25 long-duration Mir and ISS missions were divided into two age groups, i.e. 30-39 y.o. (mean 36 & 0.7, 39% of all subjects) and 40-55 y.o. (mean 46 & 0.8, 61% of all subjects). The testing was performed before launch and in flight (typically on FD-120). Age-specifc changes in the hemodynamic status were recorded in resting cosmonauts pre-flight and in spaceflight microgravity; relative dynamics of the CV parameters in response to standing posture imitation was on one and the same patterns and yet demonstrated unequal intensity before and in flight. Test results implicate that analysis and interpretation of cosmonauts' medical monitoring data should take into account individual age, which is of particular practical importance when dealing with the LBNP test data obtained in different periods of space flight.
Effect of dynamic 3-D culture on proliferation, distribution, and osteogenic differentiation of human mesenchymal stem cells
Ex vivo engineering of autologous bone tissue as an alternative to bone grafting is a major clinical need. In the present study, we evaluated the effect of 3-D dynamic spinner flask culture on the proliferation, distribution, and differentiation of human mesenchymal stem cells (MSCs). Immortalized human MSCs were cultured on porous 75:25 PLGA scaffolds for Lip to 3 weeks. Dynamically cultured cell/scaffold constructs demonstrated a 20% increase in DNA content (21 days), enhanced ALP specific activity (7 days and 21 days), a more than tenfold higher Ca(2+) content (21 days), and significantly increased transcript levels of early osteogenesis markers (e.g., COL1A1, BMP2, RUNX-2) as compared with static culture. Despite the formation of a dense superficial cell layer, markedly increased cell ingrowth was observed by fluorescence microscopy on day 21. Furthermore, increased extracellular matrix deposition was visualized by scanning electron microscopy after I and 3 weeks of dynamic culture. The observed increased ingrowth and osteogenic differentiation of 3-D dynamically cultured human MSCs can be explained by generation of fluid shear stress and enhanced mass transport to the interior of the scaffold mimicking the native microenvironment of bone cells. This study provides evidence for the effectiveness of dynamic Culture of human MSCs during the initial phase of ex vivo osteogenesis. (c) 2008 Wiley Periodicals, Inc. J Biomed Mater Res 89A: 96-107, 2009
<Go to ISI>://WOS:000263981300009
Epstein-Barr virus (EBV) latent and replicative gene transcription was analyzed in peripheral blood B-lymphocytes from astronauts who flew on short-duration ( approximately 11 days) Shuttle missions and long-duration ( approximately 180 days) International Space Station (ISS) missions. Latent, immediate-early, and early gene replicative viral transcripts were detected in samples from six astronauts who flew on short-duration Shuttle missions, whereas viral gene transcription was mostly absent in samples from 24 healthy donors. Samples from six astronauts who flew on long-duration ISS missions were characterized by expanded expression of latent, immediate-early, and early gene transcripts and new onset expression of late replicative transcription upon return to Earth. These data indicate that EBV-infected cells are no longer expressing the restricted set of viral genes that characterize latency but are expressing latent and lytic gene transcripts. These data also suggest the possibility of EBV-related complications in future long-duration missions, in particular interplanetary travel.
INTRODUCTION: Short-term spaceflight is associated with significant but reversible immunological alterations. However, little information exists on the effects of long-duration spaceflight on neuroimmune responses. METHODS: We collected multiple pre- and postflight samples from Shuttle and International Space Station (ISS) crewmembers in order to compare adrenocortical and immune responses between short- (approximately 11 d) and long-duration (approximately 180 d) spaceflight. RESULTS: In Shuttle crewmembers, increased stress hormone levels and altered leukocyte subsets were observed prior to launch and at landing. Additionally, typical stress-induced shifts in leukocyte and lymphocyte subsets, as well as the percentage of T-cells capable of producing intracellular IFN-gamma were also decreased just before launch and immediately after landing. Plasma IL-10 levels were increased before launch but not postflight. No preflight changes occurred in ISS crewmembers, but long-duration crewmembers exhibited significantly greater spikes in both plasma and urinary cortisol at landing as compared to Shuttle crewmembers. The percentage of T-cells capable of producing intracellular IFN-gamma was decreased in ISS crewmembers. Plasma IL-10 was increased postflight. Unexpectedly, stress-induced shifts in lymphocyte subpopulations were absent after long-duration flights despite significantly increased stress hormones at landing. CONCLUSION: Our results demonstrate significant differences in neuroimmune responses between astronauts flying on short-duration Shuttle missions versus long-duration ISS missions, and they agree with prior studies demonstrating the importance of mission duration in the magnitude of these changes.
OBJECT: It has been over a decade since the introduction of the da Vinci Surgical System into surgery. Since then, technology has been advancing at an exponential rate, and newer surgical robots are becoming increasingly sophisticated, which could greatly impact the performance of surgery. NeuroArm is one such robotic system. METHODS: Clinical integration of neuroArm, an MR-compatible image-guided robot, into surgical procedure has been developed over a prospective series of 35 cases with varying pathology. RESULTS: Only 1 adverse event was encountered in the first 35 neuroArm cases, with no patient injury. The adverse event was uncontrolled motion of the left neuroArm manipulator, which was corrected through a rigorous safety review procedure. Surgeons used a graded approach to introducing neuroArm into surgery, with routine dissection of the tumor-brain interface occurring over the last 15 cases. The use of neuroArm for routine dissection shows that robotic technology can be successfully integrated into microsurgery. Karnofsky performance status scores were significantly improved postoperatively and at 12-week follow-up. CONCLUSIONS: Surgical robots have the potential to improve surgical precision and accuracy through motion scaling and tremor filters, although human surgeons currently possess superior speed and dexterity. Additionally, neuroArm's workstation has positive implications for technology management and surgical education. NeuroArm is a step toward a future in which a variety of machines are merged with medicine.
The nutritional status of astronauts is altered after long-term space flight aboard the International Space Station
Defining optimal nutrient requirements is critical for ensuring crew health during long-duration space exploration missions. Data pertaining to such nutrient requirements are extremely limited. The primary goal of this study was to better understand nutritional changes that occur during long-duration space flight. We examined body composition, bone metabolism, hematology, general blood chemistry, and blood levels of selected vitamins and minerals in 11 astronauts before and after long-duration (128-195 d) space flight aboard the International Space Station. Dietary intake and limited biochemical measures were assessed during flight. Crew members consumed a mean of 80% of their recommended energy intake, and on landing day their body weight was less (P = 0.051) than before flight. Hematocrit, serum iron, ferritin saturation, and transferrin were decreased and serum ferritin was increased after flight (P < 0.05). The finding that other acute-phase proteins were unchanged after flight suggests that the changes in iron metabolism are not likely to be solely a result of an inflammatory response. Urinary 8-hydroxy-2'-deoxyguanosine concentration was greater and RBC superoxide dismutase was less after flight (P < 0.05), indicating increased oxidative damage. Despite vitamin D supplement use during flight, serum 25-hydroxycholecalciferol was decreased after flight (P < 0.01). Bone resorption was increased after flight, as indicated by several markers. Bone formation, assessed by several markers, did not consistently rise 1 d after landing. These data provide evidence that bone loss, compromised vitamin D status, and oxidative damage are among critical nutritional concerns for long-duration space travelers.
Bone loss, a key concern for long-duration space travelers, is typically considered a female issue. The number of women who have flown long-duration space missions is now great enough to allow a quantitative comparison of changes in bone and renal stone risk by sex. Participants were 42 astronauts (33 men and 9 women) on long-duration missions to the International Space Station. Bone mineral density (by dual-energy X-ray absorptiometry) and biochemical markers of bone metabolism (from blood and urine samples) were evaluated before and after flight. Data were analyzed in two groups, based on available resistance exercise equipment. Missions were 49 to 215 days in duration, flown between 2000 and 2012. The bone density response to spaceflight was the same for men and women in both exercise groups. The bone mineral density response to flight was the same for men and women, and the typical decrease in bone mineral density (whole body and/or regional) after flight was not observed for either sex for those using an advanced resistive exercise device. Biochemical markers of bone formation and resorption responded similarly in male and female astronauts. The response of urinary supersaturation risk to spaceflight was not significantly different between men and women, although risks were typically increased after flight in both groups, and risks were greater in men than in women before and after flight. The responses of men and women to spaceflight with respect to these measures of bone health were not different.