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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1984

Regulation of hematopoiesis in the suspended rat as a model for space flight

A series of studies was completed in which a variety of routine hematological and other parameters were obtained from sequential sampling of control and suspended rats. These data showed that, during suspension, the rats failed to gain weight at the same rate as the controls, ate and drank significantly less, demonstrated a transient increase in peripheral hematocrit and RBC count, a transient decrease in MCH, suppressed reticulocyte counts and a progressive decrease in MCV but no change in RBC shape. Leukocyte counts were variably decreased but no significant changes in platelet numbers were noted. Post-suspension, evidence of anemia was present from a reduced RBC count, hemoglobin, hematocrit, and MCV. A leukocytosis was also noted. Efforts directed to the collection of data aimed at understanding changes in blood volume during suspension are also discussed. As part of these studies the following parameters were investigated; RBC survival, in vitro leukocyte reactivity to PHA, bone marrow and spleen cellularity and morphology, ferrokinetics, and the hematopoietic inductive microenvironment.

Dunn, C. D. R.↗
NASA NTRS1983

Hematopoiesis in antiorthostatic, hypokinesic rats

Rats exposed to antiorthostatic, hypokinesia showed the following effects which are comparable to those seen in man during or after space flight: weight loss, reduced food and water consumption, transient increases in peripheral hematocrit and RBC count, decreasing MCV and reduced reticulocyte count. In addition, the hemoglobin P50 was shifted to the right. A significant shortening of RBC t1/2 was only seen after suspension. Changes in leukocyte and platelet numbers in suspended rats were also comparable to those in man during space flight, but leukocyte PHA sensitivity in rats showed no consistent alteration. The results demonstrate that this model reproduces many of the hematological effects of space flight and has potential as a tool in understanding the hematopoietic response to zero gravity.

Dunn, C. D. R.↗
NASA NTRS1985

Regulation of hematopoiesis in rats exposed to antiorthostatic, hypokinetic/hypodynamia. I - Model description

The effect of a 7-day suspension in a jacket and harness with 20-deg head-down tilt on body weight, food and water consumption, and hematological parameters is investigated experimentally in male Sprague-Dawley rats weighing 150-175 g. The results are presented in graphs and compared with those for unsuspended controls and with published data on rats and humans exposed to microgravity in space flight. Suspended rats are found to have reduced red-blood-cell mass, erythropoiesis, plasma volume (leading to temporarily increased hematocrit), body weight, and food and water consumption; rightward-shifted oxyhemoglobin-dissociation curves; and unchanged platelet count, leucocyte count or PHA reactivity, and red-blood-cell shape distribution. Since many of these effects are also seen in space flight, the present experimental model is considered a promising technique for simulating the hematopoietic effects of microgravity at 1 g.

Dunn, C. D. R.↗
NASA NTRS1986

Regulation of hematopoiesis in rats exposed to antiorthostatic hypokinetic/hypodynamia. II - Mechanisms of the 'anemia'

The cause of the red cell mass (RCM) deficit, which occurs in rats during suspenion, is investigated. The experimental conditions and procedures, in which male Sprague-Dawley rats are subjected to antiorthostatic hyypokinetic/hypodynamia and changes in RCM are monitored, are described. The influences of stress, reduced food and water consumption, and antiorhostatic posture on RCM are analyzed. Changes in body weight, RCM, radioiron incorporation, red blood cells (RBC), and reticulocytes, for the rats after head-down suspension are graphically presented; only the changes in RBC are related to the antiorthostatic posture. The data reveal that anemia is primarily caused by reduced food and water consumption and secondly by restricted movements.

Dunn, C. D. R.↗
NASA NTRS2001

Evolution of hematopoiesis: Three members of the PU.1 transcription factor family in a cartilaginous fish, Raja eglanteria

T lymphocytes and B lymphocytes are present in jawed vertebrates, including cartilaginous fishes, but not in jawless vertebrates or invertebrates. The origins of these lineages may be understood in terms of evolutionary changes in the structure and regulation of transcription factors that control lymphocyte development, such as PU.1. The identification and characterization of three members of the PU.1 family of transcription factors in a cartilaginous fish, Raja eglanteria, are described here. Two of these genes are orthologs of mammalian PU.1 and Spi-C, respectively, whereas the third gene, Spi-D, is a different family member. In addition, a PU.1-like gene has been identified in a jawless vertebrate, Petromyzon marinus (sea lamprey). Both DNA-binding and transactivation domains are highly conserved between mammalian and skate PU.1, in marked contrast to lamprey Spi, in which similarity is evident only in the DNA-binding domain. Phylogenetic analysis of sequence data suggests that the appearance of Spi-C may predate the divergence of the jawed and jawless vertebrates and that Spi-D arose before the divergence of the cartilaginous fish from the lineage leading to the mammals. The tissue-specific expression patterns of skate PU.1 and Spi-C suggest that these genes share regulatory as well as structural properties with their mammalian orthologs.

NASA Discipline Evolutionary Biology↗
NASA NTRS1995

The effect of space and parabolic flight on macrophage hematopoiesis and function

We used weak electric fields to monitor macrophage spreading in microgravity. Using this technique, we demonstrated that bone marrow-derived macrophages responded to microgravity within 8 s. We also showed that microgravity differentially altered two processes associated with bone marrow-derived macrophage development. Spaceflight enhanced cellular proliferation and inhibited differentiation. These data indicate that the space/microgravity environment significantly affects macrophages.

NASA Discipline Cell Biology↗
NASA NTRSDate not supplied

Utility of Terrestrial Cardiovascular Disease Data in Astronaut Radiation Risk Assessment – A Case Study Showing Increased Risk with Clonal Hematopoiesis of Indeterminate Potential

Cardiovascular disease (CVD) is associated with high doses of radiation and is are cognized health risk for astronauts on multiple or long duration exploration missions to the Moon or Mars. Currently, radiation risk assessment is based on background population disease rates and does not consider individual risk factors that may modify analysis, especially at lower radiation doses.

Zarana S Patel↗
NASA NTRSDate not supplied

Mechanical Unloading Effects Hematopoiesis and Subsequent Red Blood Cell Life Cycle Evaluated at Singe Cell Resolution

Red blood cell formation or erythropoiesis in the bone marrow and exit into circulation are known to be affected by mechanical loading. Specifically, space anemia is a condition observed during prolonged microgravity unloading in which the red blood cell (RBC) mass in circulation is reduced. However, the mechanisms causing space anemia are yet to be clearly established, but may include increased hemolysis of RBC in circulation, decreased RBC production or a combination of both factors. The presentation of space anemia is comparable to chronic anemia conditions associated with aging, disuse, and poor health. Molecular dysregulation in the RBC's life cycle is poorly defined and is a significant concern in the context of disuse anemia as mechanotransduction significantly alters of gene expression, protein synthesis and cell signaling pathways. Our study analyzes mouse single cell RNA sequencing libraries from the bone marrow, circulating blood, and spleen and integrates the RBC lineage populations from the tissues into a RBC life cycle atlas. This study also probes how age at time of spaceflight contributes to the molecular signature of space anemia. The overarching objective of the study is to develop a mechanistic understanding of space anemia and translate the findings to a better understanding of aging, disuse, and poor health-related anemia to defining the role of mechanical loading in health and devise potential therapeutic interventions. Important findings of our study are: 1) that mechanical unloading in microgravity alters the proportion of developmental RBC lineage cells, skewing toward progenitor, indicating that fewer RBCs may be present in blood; 2) that late reticulocyte number is elevated in the bone marrow of older animals, suggesting a failure to enter circulation; and 3) that the molecular signature of the circulating RBCs is not significantly altered in microgravity. However, expression markers for eryptosis and erythrophagocytosis are elevated in circulating and spleen RBCs, suggesting spaceflight may shorten the lifetime of RBCs after exit from the marrow. In conclusion our results suggest early stages of erythropoiesis proliferation and differentiation in the marrow are key factors in space anemia and mechanical loading may be a necessary step of RBC entry in circulation.

blood↗
NASA NTRS1972

Hematologic responses to hypobaric hyperoxia.

Study of the effects of hypoxia, activity, and G forces on human hematopoiesis in an attempt to elucidate these phenomena more precisely. Eight subjects were exposed to an atmosphere of 100% O2 at 258 mm Hg for 30 days, and thereafter immediately exposed to transverse G forces, simulating the Gemini flights' reentry profile. All subjects displayed a significant continuous decline in red cell mass during the exposure period, as measured by the carbon monoxide-dilution method. The Cr51 method also indicated a decline in red blood corpuscle mass. The decrease in red cell mass was due to suppression of erythropoiesis and to hemolysis. After exposure to hyperoxia, all subjects exhibited elevated plasma hemoglobin levels, decreased reticulocyte counts, and decreased red cell survivals. CO production rates and urine erythropoietin levels were unchanged. Two hours after termination of exposure to hyperoxia, all subjects exhibited increased reticulocyte counts which were sustained for longer than two weeks. The progressive decrease in red cell mass was promptly arrested on return to ground level atmospheres. Within 116 days after exposure to hyperoxia, the hematologic parameters of all eight subjects had returned to control levels.

Larkin, E. C.↗
NASA NTRS1989

The effects of simulated hypogravity on murine bone marrow cells

Mouse bone marrow cells grown in complete medium at unit gravity were compared with a similar population cultured in conditions that mimic some aspects of microgravity. After the cells adjusted to the conditions that simulated microgravity, they proliferated as fetal or oncogenic populations; their numbers doubled in twelve hour periods. Differentiated subpopulations were depleted from the heterogeneous mixture with time and the undifferentiated hematopoietic stem cells increased in numbers. The cells in the control groups in unit gravity and those in the bioreactors in conditions of microgravity were monitored under a number of parameters. Each were phenotyped as to cell surface antigens using a panel of monoclonal antibodies and flow cytometry. Other parameters compared included: pH, glucose uptake, oxygen consumption and carbon-dioxide production. Nuclear DNA was monitored by flow cytometry. Functional responses were studied by mitogenic stimulation by various lectins. The importance of these findings should have relevance to the space program. Cells should behave predictably in zero gravity; specific populations can be eliminated from diverse populations and other populations isolated. The availability of stem cell populations will enhance both bone marrow and gene transplant programs. Stem cells will permit developmental biologists study the paths of hematopoiesis.

Lawless, Desales↗
NASA NTRS1996

Immunological and Hematopoietic Biotechnology Studies

The purpose of the work carried under this interchanges was to support the development of space flight biotechnology experiments in the areas of immunology and hematopoiesis to facilitate the commercial development of space. The studies involved the interaction and development of experiments with biotechnology companies for necessary ground-based studies to allow the development of flight studies. The thrust of the work was to develop experiments with the Chiron Corporation and Bioserve involving the use of interleukin-2 to modulate the effects of spaceflight on immune responses. Spaceflight has been shown to have multiple effects on immune responses (1). lnterleukin-2 is an immuno-regulator that could have potential to counter some of the alterations induced in immune responses by spaceflight (1). To test this possibility before flight, rats were suspended antiorthostatically (2) and treated with interleukin-2. Antiorthostatic suspension is a model for some of the effects of spaceflight on immune responses (2). The interleukin-2 was given to see if it could alter some of the effects of suspension. This was achieved. As a result of these studies, two flight experiments were developed and flown with the Chiron Corp. And Bioserve to determine if use of interleukin-2 could prevent or attenuate the effects of space flight on immune responses.

Fernandez-Botran, Rafael↗