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PubMedDate not supplied

[The technical requirements for artificial life support systems].

The author advances a summarized concept of the bioartificial organism consisting of an operator, equipment and biological medium. Formulates the principle of man-made life support, reviews a model of the bioartificial organism and a classification of processors that ensure the control of the physiological status of the biological medium.

Artificial Organs↗
PubMedDate not supplied

[Chufa (Cyperus esculentus) as a source of vegetable fats in a sealed life-support system].

The cultivation schemes, productivity, total biochemical, lipid in particular, composition of nodules of chufa (Cyperus esculentus) were studied, using a phytotron. Upon continuous illumination chufa yielded a high total productivity and a satisfactory coefficient of economic effectiveness (not less than 50%). Chufa nodules have an optimal ratio of proteins, carbohydrates and fats containing essential fatty acids. To meet man's requirements for vegetable oils and essential fatty acids, it is necessary to produce daily 150--200 g dry chufa nodules which are quite acceptable as a dietary ingredient.

Carbohydrates↗
PubMed1978

Organ culture of canine prostate.

The simple life support system of organ culture contrasts sharply with the life support system in vivo. Organ culture, a technique for characterizing the effect of various substances on an organ, has potential clinical usefulness in many areas. In the present case explants of canine prostate are minimally maintained when cultivated in a medium enriched with testosterone and insulin. Pretreatment of the dog with methylprednisolone or the addition of vitamin A markedly improves the maintenance of normal structure. Methylprednisolone pretreatment and the addition of vitamin A had a significant synergistic effect. The clinical significance and implications of the findings are presented. We believe these preliminary experiments with organ culture can serve as a basis for deciphering some of the complex functions or an organ.

Animals↗
PubMed1975

Biothermal simulation of scuba divers.

A biothermal model of the immersed man is presented and validated. Comparisons are made between analytic and experimental values of temperature-vs-time profiles for neck-immersed seminude and wet-suited subjects. An engineering example is presented to demonstrate how the model may be used to evaluate proposed life-support system designs.

Body Temperature Regulation↗
PubMed1979

Oxygen levels safe for continued reproduction of Drosophila in normal and hypobaric atmospheres.

Reproduction of the fruit fly, Drosophila melanogaster was examined in various combinations of oxygen concentration and total atmospheric pressure in an effort to establish extremes within which continued reproduction can take place. The effects of temperature were also examined. At 760 torr total pressure, it was found that reproduction could take place between 10% oxygen, PO2 = 76 torr, and 38% oxygen, PO2 = 288 torr, at a temperature of 26 degrees C. At 18 degrees C, the lower limit remained the same but the upper limit rose to 60% oxygen, PO2 = 456 torr. In hypobaric atmospheres totalling 250 torr, the low extreme was 30% oxygen, PO2 = 75 torr, and the upper level was 80% oxygen, PO2 = 200 torr. Because closed ecology life support systems proposed for future space programs will include similar small organisms with short life cycles, the author encourages similar reproductive studies with species most likely to accompany humans into space.

Atmospheric Pressure↗
PubMedDate not supplied

[Model of an ecological system closed as regards gas metabolism and with a periodically working autotrophic component. I. Conditions for stability of the atmospheric system].

The paper describes a semi-closed ecological system consisting of a man and a photosynthetic autotrophic component. The conditions required to maintain the stability of the atmosphere in the system are described as applied to two alternating modes of the function of the autotrophic component. These conditions express equal quantities of oxygen and carbon dioxide consumed and produced by the components of the system during any time period the length of which is the duration of the cycle of the system. On this basis equations have been derived which help to identify the photosynthetic cultures that can be used as an autotrophic component in a closed man-sustaining life support system.

Ecological Systems, Closed↗
PubMed1976

Effect of chronic centrifugation of the musculoskeletal system of the dog.

Sixteen male Beagle dogs, 293 to 509 days old, were exposed almost continuously for 3 months to 2.0 G on a 7.9 meter radius centrifuge. The dogs were maintained on the centrifuge, by means of a specially designed automated waste disposal and life support system. As compared to the mean values of normal gravity controls, centrifuged dogs showed no differences in femur length; cross-sectional area, outer and inner radii at mid-shaft of the femur; dry weights of the biceps femoris, quadriceps femoris, and gastrocnemius muscles. It was shown by analysis of covariance that chronic centrifugation has no effect on the relationship between the length and the cross-sectional dimensions at mid-shaft of the femur. Photon absorptiometry, however, revealed significant mineral content increases averaging 1.5% at 3 sites, i.e., at the 1/4, 1/2 and 3/4 length of the femur.

Animals↗
PubMed1990

The development of a climate for caring: a historical review of premature care in the United States from 1900 to 1979.

The data presented in this review of the history of premature care in the United States is limited to published material available within the local area. Additional manuscripts, records, and oral histories, would provide a more comprehensive perspective. The period from 1900 to the early 1940s represents the beginning of premature care in the United States characterized by efforts to provide an intrauterinelike environment. Energies were focused on the three identified basic needs of temperature support, nutrition, and protection against infection. The idea of caring for prematures in an especially designated area in the hospital evolved, and premature stations or wards were created. Advances in technology resulted in sophisticated systems for providing warmth for infants and some interventions for respiratory support using oxygen and an infant ventilator. The dangers of cold stress during transport were addressed with attempts to provide warmth using an especially designed transport incubator. A revolutionary growth in technology combined with the nationwide coordinated effort for organizing regional care has characterized this past 30-year period of premature care (1950-1980). The infant is now surrounded by sophisticated life-support systems and receives medical care from a much broader knowledge base than was available in the past. The environment for premature care has truly surpassed any expectations that health care professionals of the past may have held when the concept of an incubator emerged. Nursing of premature infants has expanded with the level of sophisticated equipment and the knowledge of the premature infant's physiologic needs. Nurses are no longer the gatekeepers of a sanctuary against infection. They care for the premature and the family by providing support, information, and caring during an emotionally stressful time. As the premature's physiological condition stabilizes, the nurse helps the family learn to care for the infant and thus transfers the responsibility of providing warmth, nutrition, and protection to the parents. Nurses are now gatekeepers of a very special sanctuary--the sanctuary of caring.

History, 20th Century↗
PubMed1991

A chamber system for maintaining a hyperbaric environment for long-term animal studies.

An experimental hyperbaric chamber system is described whereby animals, including nonhuman primates, can be cared for under altered environmental conditions for periods in excess of 1 wk. The chamber itself is capable of a working pressure of 200 atm abs, used with various mixtures of gases which can be varied independently. The novel approach of vertical mounting enables cages to be lowered into position, and food and water can be supplied from above while excreta can be removed from below, irrespective of the internal pressure. The chamber has an integrated life support system such that temperature, both of the chamber and of the mass of gas inside, humidity, oxygen, carbon dioxide, and noise levels can be accurately and finely controlled, all within a pathogen-free environment.

Animals↗
PubMed1990

Reproduction in the space environment: Part I. Animal reproductive studies.

Mankind's exploration and colonization of the frontier of space will ultimately depend on men's and women's ability to live, work, and reproduce in the space environment. This paper reviews animal studies, from microorganisms to mammals, done in space or under space-simulated conditions, which identify some of the key areas which might interfere with human reproductive physiology and/or embryonic development. Those space environmental factors which impacted almost all species included: microgravity, artificial gravity, radiation, and closed life support systems. These factors may act independently and in combination to produce their effects. To date, there have been no studies which have looked at the entire process of reproduction in any animal species. This type of investigation will be critical in understanding and preventing the problems which will affect human reproduction. Part II will discuss these problems directly as they relate to human physiology.

Animals↗
PubMed2026

Using Organoids to Unlock the Potential of Human Torpor for Spaceflight.

PURPOSE OF REVIEW: This paper reviews the current understanding of the potential for humans to enter a state of torpor/hibernation, and discusses the possibility of inducing torpor in astronauts for long-duration space travel, including some of the physiological, technological, and ethical considerations associated with its implementation. By exploring means to induce torpor in various human organoid systems, we hope such research can provides insights to comprehensive solutions to overcome some of the major hurdles that limit the potential for human to enter a state of torpor during long-duration deep-space missions, and contribute to the ongoing efforts to make such missions more feasible and safer for astronauts. RECENT FINDINGS: On future deep space missions such as NASA's planned missions to the Moon, Mars, and near-Earth asteroids, astronauts will be continuously exposed to environments that are radically different from those on Earth, each presenting multiple logistical and physiological challenges. Beyond the well-documented physiological effects of microgravity, space travelers will encounter a complex radiation environment that may contribute to significant short- and long-term adverse effects on human physiology and increase the risk of cancer and other diseases. Besides these physical challenges, life support systems must also be designed to mitigate psychological impacts of long-term isolation and confinement - all of which collectively pose formidable engineering problems. Hibernation/torpor is a state of prolonged inactivity and metabolic depression used by a wide variety of mammals to survive periods of cold temperatures and food scarcity, including some primates and perhaps even an extinct early line of hominins that lived nearly half a million years ago. Since modern humans share common ancestry with these hominins and hibernating primates, it is likely the human genome encodes the necessary genetic information to hibernate, or at least enter the similar, more transient state of torpor. The reduced body activity, lowered metabolism, and decreased energy requirements that characterize torpor suggest that developing means of inducing such a state in astronauts could address these challenges, including providing a degree of radioprotection. SUMMARY: This review explores the potential application of human torpor as a countermeasure to address the many challenges posed by long-duration spaceflight beyond low-Earth orbit (LEO), discusses various natural hibernating model systems for studying means of inducing a torpor-like state in humans, and highlights the vast potential of using human organoids to test and validate mechanisms that govern induction and maintenance of torpor to identify the means to one day safely induce this state in astronauts to provide additional protection from the myriad stressors of spaceflight.

Astronaut Health↗
PubMed1990

Development of ophthalmoplegia in amyotrophic lateral sclerosis during long-term use of respirators.

Patients with amyotrophic lateral sclerosis (ALS), who survive longer on a life-support system, exceeding the natural course of this disease, show new features of ALS. We report here a clinico-pathologic study of a 51-year-old patient with sporadic ALS who developed progressive external ophthalmoplegia 3 years after he remained on a respirator and died 5 years later, 13 years after the onset of his illness. The external ophthalmoplegia was initially accompanied by preserved doll's eye phenomenon, which later became absent. Autopsy revealed not only degeneration of the upper and lower motor neuron systems typical of ALS, but also degeneration of the Clarke's dorsal nuclei, spinocerebellar tracts, substantia nigra and inferior olives in addition to intracytoplasmic neuronal inclusion bodies in various areas. The oculomotor and abducens nuclei were variably involved, accompanied by neurogenic atrophy of the extraocular muscles. Our case report is consistent with the idea that ALS comprises a heterogeneous group of disorders, and also indicates that long-term use of respirators may make some patients with this illness prone to developing atypical clinical and neuropathologic features which are not observed during the natural course of ALS.

Amyotrophic Lateral Sclerosis↗
PubMed1992

"Locked-in syndrome" after intrathecal cytosine arabinoside therapy for malignant immunoblastic lymphoma.

A 22-year-old man with malignant immunoblastic lymphoma had "locked-in" syndrome within 48 hours of receiving a single (100 mg) dose of intrathecal cytosine arabinoside (ara-C) in conjunction with intravenous ara-C, cisplatin, and doxorubicin. Eight hours after therapy, the patient had central hypoventilation and blurred vision that progressed to blindness within 3 hours. During the next 10 hours, he became completely quadriplegic but remained intermittently alert and was able to respond to commands by eye or head movements. Radiographic studies showed necrosis of the medulla and swelling of the entire spinal cord. The patient persisted in a locked-in state until his death 3 weeks later, after removal of life support systems. Autopsy confirmed extensive necrosis of the lower medulla, optic chiasm, cranial nerves I and IV, and spinal cord. This case was unusual for its severity. The temporal relationship to ara-C instillation favors a toxic idiosyncratic response to chemotherapy. The authors advocate caution when bolus intrathecal and intravenous ara-C are administered to a patient within a short time of each other.

Adult↗