Search NASA⌕ Search

SEARCH · Search NASA

Results for “BLOOD”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 235 records · Page 13
All sourcesNASA NTRSDOE OSTI
NASA NTRS1980

Comparison of early reactions of the blood system in rats to immobilization, the action of hypoxia and the administration of erythopoietin

Three series of experiments were simultaneously carried on rats with the purpose of studying the action of different stimulants on the blood system; rats were subjected to immobilization, hypoxic hypoxia and erythropoietin administration. Changes in various cellular forms in the bone marrow, the thymus and the spleen were studied. A unitypical reaction, as in stress, was noted during the first hours; a reduction of the cell count in the lymphoid organs, a reduction of granulocytes and an increase of lymphoid cells in the bone marrow. The differences were chiefly quantitative. This was followed by stimulation of myelo and erythropoiesis determined by the specific features of the action applied. Nonspecific blood reaction was apparently due to activation of the adaptation mechanisms.

Gorizontov, P. D.↗
NASA NTRS1982

The effects of horizontal body casting on blood volume, drug responsiveness, and +Gz tolerance in the rhesus monkey

To simulate the weightless condition, eight rhesus monkeys, instrumented with solid-state pressure transducers, were horizontally restrained in body casts for 28 days. Blood volume decreased an average of 13% after 14 days of restraint, due mainly to a drop in plasma volume. Aortic pressure and heart rate responses to norepinephrine and phenylephrine decreased after 14 days of restraint. The monkeys did not show a statistically significant decreased tolerance to a 90 deg sudden upright tilt after horizontal restraint. During the fifth week of casting, four animals were subjected to +Gz acceleration tests on a centrifuge. The acceleration tolerance of the casted monkeys was significantly reduced compared to four similarly instrumented control animals. These findings indicate that the cardiovascular deconditioning associated with simulated weightlessness results from an inability to maintain central blood volume during orthostatic stress.

Dickey, D. T.↗
NASA NTRS1985

Probe Follower for Moving Blood Vessels

Probes track vessel expansion and contraction with minimal perturbation. Nozzle back-pressure changes at cuff on blood vessel basis for monitoring position of probe in blood vessel. Fluidic amplifiers use signals to control three-axis servo that centers measuring probe between sensing-nozzle pairs at cuff.

Frazer, R. E.↗
NASA NTRS1985

Blood Pressure Responses and Mineral Ocorticoid Levels in the Suspended Rat Model for Weightlessness

Cardiovascular responses and fluid/electrolyte shifts seen during space flight are attributed to cephalad redistribution of vascular fluid. The antiorthostatic (AO) rat (suspended head down tilted, 15-20 deg) is used to model these responses. Current studies show that elevated blood pressures in A0 rats are sustained for periods up to seven days. Comparisons are made with presuspension rats. Increased blood pressure in head down tilted subjects suggests a specific response to A0 positioning, potentially relatable to cephalad fluid shift. To assess a role for hormonal regulation of sodium excretion, serum aldosterone levels were measured.

Musacchia, X. J.↗
NASA NTRS1986

An analysis of estimation of pulmonary blood flow by the single-breath method

The single-breath method represents a simple noninvasive technique for the assessment of capillary blood flow across the lung. However, this method has not gained widespread acceptance, because its accuracy is still being questioned. A rigorous procedure is described for estimating pulmonary blood flow (PBF) using data obtained with the aid of the single-breath method. Attention is given to the minimization of data-processing errors in the presence of measurement errors and to questions regarding a correction for possible loss of CO2 in the lung tissue. It is pointed out that the estimations are based on the exact solution of the underlying differential equations which describe the dynamics of gas exchange in the lung. The reported study demonstrates the feasibility of obtaining highly reliable estimates of PBF from expiratory data in the presence of random measurement errors.

Srinivasan, R.↗
NASA NTRS1987

Measurement of Human Blood and Plasma Volumes

Report reviews techniques for measuring blood-plasma volume in humans. Common technique of using radioactive iodine isotope to label plasma albumin involves unwarranted risks from low-level radiation. Report emphasizes techniques using Evans-blue-dye (T-1824) labeling of albumin, hematocrit or hemoglobin/hematocrit measurements, or blood densitometry. In Evans-blue-dye technique, plasma volume determined from decrease in dye concentration occurring after small amount of dye solution injected into circulatory system. Subjection of Evans blue dye to test for carcinogenicity gave negative results.

Greenleaf, J. E.↗
NASA NTRS1988

Implanted Blood-Pressure-Measuring Device

Arterial pressure compared with ambient bodily-fluid pressure. Implanted apparatus, capable of measuring blood pressure of patient, includes differential-pressure transducer connected to pressure sensor positioned in major artery. Electrical signal is function of differential pressure between blood-pressure sensor and reference-pressure sensor transmitted through skin of patient to recorder or indicator.

Fischell, Robert E.↗
NASA NTRS1988

Extending The Shelf Life Of Blood Platelets

New method of storing human blood platelets extends vitality for transfusions. Packaged as suspension in sterile liquid in plastic blood bags. Each bag placed between pair of plastic grids, and rubberbands placed around sandwich thus formed to hold together. Stored upright in open air or in container through which air pumped at rate of at least 45 L/min. Ensures that platelets receive ample oxygen and expiratory carbon dioxide form platelets removed before pH drops to harmful levels.

Surgenor, Douglas M.↗
NASA NTRS1988

Measuring Time-Averaged Blood Pressure

Device measures time-averaged component of absolute blood pressure in artery. Includes compliant cuff around artery and external monitoring unit. Ceramic construction in monitoring unit suppresses ebb and flow of pressure-transmitting fluid in sensor chamber. Transducer measures only static component of blood pressure.

Rothman, Neil S.↗
NASA NTRS1990

Computing Blood Flows

Methods developed for aerospace applied to mechanics of biofluids. Report argues use of advanced computational fluid dynamics to analyze flows of biofluids - especially blood. Ability to simulate numerically and visualize complicated, time-varying three-dimensional flows contributes to understanding of phenomena in heart and blood vessels, offering potential for development of treatments for abnormal flow conditions.

Kwak, D.↗
NASA NTRS1992

Altered baseline blood volume and the norepinephrine response to stress in humans

A hypothesis is proposed that a primary physiological purpose of the neural and endocrine response to stressors is the preservation of the blood volume/blood pressure relationship. Changes in blood volume caused by an adaptation to the environmental challenge serve to modulate the neural and endocrine responsiveness to stress. Relationships between changes in vascular volume, vasoconstriction, and norepinephrine (NE) responses during acute and chronic exposure to various stressors are examined. It is noted that the hypothesis is based on numerous observations rather than definitive cause-effect experiments and further investigation is required to prove it.

Vernikos, J.↗
NASA NTRS1991

Blood and urine responses to ingesting fluids of various salt and glucose concentrations

To compensate for the reduced blood and fluid volumes that develop during weightlessness, the Space Shuttle crewmembers consume salt tablets and water equivalent to 1 l of normal saline, about 2 hrs before landing. This paper compares the effects on blood, urine, and cardiovascular variables of the ingestion of 1 l of normal (0.9 percent) saline with the effects of distilled water, 1 percent glucose, 0.74 percent saline with 1 percent glucose, 0.9 percent saline with 1 percent glucose, and 1.07 percent saline. It was found that the expansion of plasma volume and the concentration of urine were greater 4 hrs after ingestion of 1.07 percent saline solution than after ingestion of normal saline and that the solutions containig glucose did not enhance any variables as compared with normal saline.

Frey, Mary A.↗
NASA NTRS1993

Blood volume reduction counteracts fluid shifts in water immersion

Six healthy men were bled by 15 percent of their total blood volume (TBV) before 7 h of seated water immersion, to test the hypothesis that some of the major physiological responses to an expansion of central blood volume can be counteracted by prior reduction of TBV. Subjects were their own controls under two conditions: seated dry in air and seated immersed to the suprasternal notch in water. Immersion without prior reduction of TBV Wet Control (WC) caused a statistically significant 22-percent increase in cardiac output (CO), 368-percent increase in urine production, and 200-percent increase in sodium excretion relative to dry control (DC) sessions. When TBV was reduced before immersion, CO was the same as during DC sessions; however there were significant increases above DC in urine flow (+73 percent) and sodium excretion (+120 percent), although they were significantly reduced from WC values. Potassium excretion was similar during DC and WC sessions, but was significantly increased (+75 percent) when subjects were immersed after 15-percent reduction of TBV.

Simanonok, Karl E.↗
NASA NTRS1990

Alanine increases blood pressure during hypotension

The effect of L-alanine administration on blood pressure (BP) during haemorrhagic shock was investigated using anesthetized rats whose left carotid arteries were cannulated for BP measurement, blood removal, and drug administration. It was found that L-alanine, in doses of 10, 25, 50, 100, and 200 mg/kg, increased the systolic BP of hypotensive rats by 38 to 80 percent (while 100 mg/kg pyruvate increased BP by only 9.4 mmhg, not significantly different from saline). The results suggest that L-alanine might influence cardiovascular function.

Conlay, L. A.↗
NASA NTRS1993

Rotary blood pump

A rotary blood pump is presented. The pump includes a pump housing for receiving a flow straightener, a rotor mounted on rotor bearings and having an inducer portion and an impeller portion, and a diffuser. The entrance angle, outlet angle, axial, and radial clearances of the blades associated with the flow straightener, inducer portion, impeller portion, and diffuser are optimized to minimize hemolysis while maintaining pump efficiency. The rotor bearing includes a bearing chamber that is filled with crosslinked blood or other bio-compatible material. A back emf integrated circuit regulates rotor operation and a microcomputer may be used to control one or more back emf integrated circuits. A plurality of magnets are disposed in each of a plurality of impeller blades with a small air gap. A stator may be axially adjusted on the pump housing to absorb bearing load and maximize pump efficiency.

Bozeman, Richard J.↗
NASA NTRS1994

Method and apparatus for the collection, storage, and real time analysis of blood and other bodily fluids

The present invention provides a simple, portable, relatively inexpensive apparatus for accurately and efficiently collecting, separating, testing, and even storing between about 1-20 ml, preferably about 1-10 ml, of blood or other bodily fluid in situ. The apparatus includes a collection chamber bounded on its sides by an opening in a sheet of material, preferably clear plastic, abutting a filter card. The filter card is made of fibrous material, preferably less than about a millimeter thick, having an average pore size of less than about 3 microns. Preferably, the fibers are glass and the fibrous material has an average pore size of about 1 micron. The fibrous material is treated with a carbohydrate/protein mixture which contains between about 1-40 percent wt/vol carbohydrate and about 0.1-15 percent wt/vol nonspecific protein, preferably between about 10-20 percent carbohydrate and about 5-8 percent protein. A preferred carbohydrate/protein mixture comprises about 10 percent mannitol and about 6 percent albumin. The blood or other fluid moves through the filter card by capillary action aided by an absorbent matrix with a high Klemm factor which abuts the filter card. The absorbent matrix and/or filter card can be treated with a wide spectrum of test reagents. The speed, cleanliness, and efficiency of the separation process can be altered by: (a) changing the absolute concentration of the carbohydrate/protein mixture; (b) applying positive or negative pressure to one side of the filter; and/or (c) varying the relative density and pore size of the filter card and absorbent matrix.

Whitson, Peggy A.↗
NASA NTRS1992

Blood volume and orthostatic responses of men and women to a 13-day bedrest

Changes in blood volume during space flight are thought to contribute to decrements in postflight orthostatic function. The purpose of this study was to determine whether gender affects red cell mass and plasma volume during a short exposure to simulated microgravity, and whether gender differences in orthostatic tolerance ensure. Methods: Ten men (31.5 plus or minus 5.2 years, STD) and eleven normally menstruating women (33.3) plus or minus 6.0 STD) underwent 13 days of 6 degree head-down bedrest. Plasma volume (Iodine 125 labeled human serum albumin) and red cell mass (Carbon 51 labeled red blood cells) were measured before bedrest and on bedrest day 13. On the same days, orthostatic tolerance (OT) was determined as the maximal pressure during a presyncopalimited lower body negative pressure test. Results: Plasma volume (PV) and red cell mass (RCM) decreased in both groups with a greater PV decrease (P less than 0.05) in men (6.3 plus or minus 0.7 ml/kg) than in women (4.1 plus or minus 0.6 ml/kg). Decreases in red cell mass were similar (1.7 plus or minus 0.2 ml/kg in men and 1.7 plus or minus 0.2 ml/kg in women). OT was similar for men and women before bedrest (minus 78 plus or minus 6 mmHg in men versus minus 70 plus or minus 4 mmHg in women) and decreased by a similar degree (by an average of 11 mmHg in both groups) after bedrest. The changes in OT did not correlate with changes in plasma volume during bedrest (r(exp 2) = 0.002). Conclusion: Thus, although female hormones may protect PV during bedrest, they do no appear to offer an advantage in terms of loss of orthostatic function.

Fortney, S.↗
NASA NTRS1995

Effects of chronic elevated levels of CO2 on the concentration of blood cellular elements and plasma corticosterone in the male rat

The mean CO2 concentration on the Space Shuttle is 0.3% and has reached 0.7%, for extended periods of time. Following space flight, it has been shown that both humans and animals have significant changes in red blood cell counts (RBC) and white blood cell counts (WBC). In other studies, where no significant change did occur in the total WBC, a significant change did occur in the distribution of WBC. WBC are affected by circulating levels of glucocorticoids, which often increase when animals or humans are exposed to adverse and/or novel stimuli (e.g. elevated CO2 levels or weightlessness). The purpose of this study was to determine if elevations in CO2 concentration produce changes in total WBC and/or their distribution.

Alexander, R. A.↗