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At least 1,135 records · Page 63Linked to original sources
PubMed1993

Bioregenerative life support as self-sustaining ecosystem in space.

Recent results of research on the development of biological systems and the related technologies for life support ecosystem in space have been reviewed. The integration of higher plants and algal subsystems and the technologies for food and atmospheric regeneration, water reclamation as waste recycling are the aspects which have been dealt with and need critical evaluation before they can be tested in space. The adaptation of living organisms and their ability to multiply and regenerate in space environment during long duration missions is one of the important criteria for their final selection. It is not yet clear to what extent bioregenerative subsystems can be accommodated in the space station Freedom, which will depend on their mass and functional stability, maintainability and operational cost. But it can be expected that bioregenerative life support systems will continue to evolve during the life time of space station Freedom leading towards an integrated ecosystem with further simplification and an increased degree of closure. Several biological and physico-chemical life support systems currently developed are under investigation on the MIR space station.

Animals↗
PubMed1998

Insight into mechanisms of reduced orthostatic performance after exposure to microgravity: comparison of ground-based and space flight data.

Since the beginning of human spaceflight, the value of understanding mechanisms of physiological adaptation to microgravity became apparent to life scientists who were interested in maintining crew health and developing countermeasures agains adverse effects of the mission. However, several characteristics associated the the logistics of spaceflight presented significant limitations to the scientific study of human adaptation to microgravity. Because space missions are so infrequent and involve minimal numbers of crewmembers, meaninful statistical analysis of data are limited. Reproducibility of results from spaceflight experiments is difficult to assess since there are few repeated space missions involving the same crewmembers. Since the emphasis of space missions is placed on operations, experiments are compromised without adequate control over various factors (e.g., time, diet, physical activities, etc.) that can impact measured responses. With the mimimal opportunity to collect spaceflight data, there is a high risk of experiments that simultaneously interfere with other experiments by the increasing demand on the crewmembers to participate in mumerous experiments proposed by multiple investigators. The technology and ability to measure physiological functions necessary to test specific hypotheses can be severely limited by physical space and power constraints of the space enviroment. Finally, technical and logistical aspects of space missions such as launch delays, extended missions, and inflight operational emergencies can significantly compromise the timing and control of experiments. These limitations have stimulated scientists to develop ground-based analogs of microgravity in an effort to investigate the effects of spaceflight on physiological function in a controlled experimental setting. The purpose of this paper is to provide a selected comparison of data collected from ground-based experiments with those obtained from spaceflight in an effort to assess the adequacy of ground analogs of actual flight for the study of human physiological adaptation to microgravity. Specifically, results from ground and spaceflight will be used to provide insight into mechanisms underlying adaptations of blood pressure regulation and reduced orthostatic performance to the microgravity environment.

Adaptation, Physiological↗
PubMed2001

[G-tolerance of female cosmonauts during descent in space flights of 8 up to 169 days in duration].

Investigations into g-tolerance of female cosmonauts during descent in space flights of varying duration are topical for the present day, as there are little data on this issue. Tolerance of +Gz-loads during descent was analyzed based on the data about 4 female cosmonauts in 5 space flights. The space flights were conventionally divided into short- (8-16 days) and long-term (169 days). In two space flights (16 and 169-d long), tubeless anti-g suit Centaur was warn during descent. In these space flights, g-tolerance of females was quite satisfactory advocating for the possibility for women to fly to space without any constraints. When the anti-g suit was not used, female physiological systems were stressed heavier than male. The spacesuit smoothed away this difference. Our results evidence a distinct positive effect of wearing the anti-g suit by female cosmonauts during descent as it reduces stress to their physiological systems.

Adaptation, Physiological↗
PubMed1977

Growth-rate periodicity of Streptomyces levoris during space flight.

Streptomyces levoris Kras was used is an experimental test micro-organism during the Apollo Soyuz Test Project to study alternating vegetative mycelial and spore ring periodicity during space flight. Four cultures were launched in each of the spacecrafts (Apollo and Soyuz). During the joint space-flight activities, two cultures from each spacecraft were exchanged. Selected duplicate cultures were maintained as controls in both the USA and the USSR. Spore ring morphology was periodically documented by photographing the specimens at approximately 12-hr intervals during the pre-, in-, and post-flight periods of the experiment. A decreased growth-rate periodicity in all but one of the eight space-flight cultures was in part attributed to the reduced temperature in the spacecraft. One of the eight cultures grew at a faster rate in the reduced temperature environment of Apollo than did the ground controls. Three of the space-flight cultures developed double spore rings during the immediate post-flight period. This anomaly was attributed to re-entry into the earth's gravity. The absence of spores in portions of one ring formed during space flight may have been caused by nutritional defects or media abnormality. Extensive studies will be required to elucidate the cause of this detect with certainty. There was no visible evidence of wedges in the cultures which would suggest naturally occurring or radiation-induced mutagenic alteration during space flight.

Circadian Rhythm↗
PubMed1997

Deviance among expeditioners: defining the off-nominal act through space and polar field analogs.

The space venture resembles other extreme environmental exploration in many respects. Since the beginning of the space program, social and behavioral scientists have predicted that space crews increasingly will begin to experience the kinds of deviant behaviors seen in other extreme environmental duty settings as mission duration, crew size, and heterogeneity increases. However, there has been a long history of neglect by the nation's space agency of those psychosocial human factors which will play such a vital role in future manned spaceflight. The author argues that this is counterproductive, even dangerous, and that social and behavioral studies must be conducted to generate baseline data regarding dysfunctional acts in extreme environments, including the milieu of the space mission. An obstacle to studying occurrences and frequencies of deviant acts is the absence of a standardized definition of such acts in the extreme environment. Borrowing the sanitized NASA term "off-nominal", which generally refers to a maladaptive action, a preliminary reliability test was conducted among five scientists who work with human interaction in extreme environments. They were asked to rate situations from several actual space and polar expeditions for numbers of off-nominal acts. They were told the object of the exercise was to derive a standardized definition and were not provided with any specific definition of off-nominality. Substantial agreement in their ratings provided reliable information to construct a working definition of off-nominality. Various interactions and behaviors which respondents deemed off-nominal could be subsumed under poor expertise, mental disorder, forms of abuse and interpersonal insensitivity, problems of authority and responsibility, task deficits, poor hygiene and fitness, poor field-base communication, and human error with equipment from violating safety procedures and poor judgment as to its usage.

Adaptation, Psychological↗
PubMed1993

The effect of space flight on human cellular immunity.

T-lymphocyte responsiveness to mitogens is depressed by an average of 56% in humans (129 subjects) tested during and after space flight. Although there is not yet conclusive evidence of a clinical significance of the test, it is clear that factors of space flight like stress, closed environment and cosmic radiation may affect immune responsiveness. The data obtained from space crews may be compared to the depression seen in subjects undergoing heavy physical stress of head down tilt bedrest. Recently, delayed hypersensitivity [correction of hypersensivity] response was tested on crews of the US space shuttle and of the orbital station MIR by means of a commercially available "skin test". Again, the response was lower in 14 of the 15 subjects tested. In two cases, a strong in flight depression could be related to heavy physical and psychological stress experienced in flight. The data available today are not sufficient to draw conclusions on the hazard of infectious diseases during and after space flight. Although the changes observed never harmed the health of astronauts, immunological changes must be seriously investigated and understood in view of long-duration flights on space stations in an Earth orbit and to other planets like Mars and the Moon.

Adult↗
PubMed2003

Putting the International Space Station to work.

The International Space Station (ISS) is the largest international cooperative science and technology project ever undertaken. Involving the United States, Russia, Japan, Canada and 10 ESA Member States, it is now rapidly becoming a reality in orbit, offering unprecedented access for research and applications under space conditions. Europe has invested heavily in this endeavour and plans to exploit that investment by a vigorous utilisation of the ISS for life and physical sciences research and applications, space science, Earth observation, space technology development, the promotion of commercial access to space, and the use of space for educational purposes. In recent years, ESA has engaged in an intensive promotional effort to encourage potential user communities to exploit the novel opportunities that the ISS offers. It has also made significant financial commitments to develop both multi-user facilities for life and physical sciences studies in the Columbus Laboratory, and observational and technology exposure instruments using the external Columbus mounting locations, as well as giving financial support to promote commercial and educational activities. ESA has now elaborated a European Strategy for the efficient utilisation of the ISS by European scientists and other users, which is being coordinated with the Agency's Member States contributing to the ISS Programme, and with the European Science Foundation (ESF). In cooperation with the European Commission, ESA is also fostering synergy with the European Commission's Framework Programmes in terms of shared R&D objectives. This article describes the plan that has been evolved to integrate all of these various elements.

Astronomical Phenomena↗
PubMedDate not supplied

Glass fiber reinforced composite resin space maintainer: case reports.

PURPOSE: Glass fiber reinforced composite resins (GFRCR) are new to the pediatric dental market and can be an alternative to conventional space maintenainers. GFRCRs have been developed for dental applications during the past several years. This preliminary clinical study described the treatment of patients whose missing primary molars were restored with everStick, a semimanufactured product made of glass fibers, thermoplastic polymer, and lightcuring resin matrix for reinforcing dental polymer. METHODS: everStick was applied as a space maintainer when there was a loss of 1 or 2 teeth in the maxillary or mandibular arch. RESULTS: This study showed that the GFRCR space maintainers functioned well during a short period. The clinical advantages of the GFRCR space maintainers were that they: provided cost and time savings; did not require a cast model; did not require a second visit; were easy to apply; provided reliable adhesive bonding; provided long-term retention; were used when there was an indication of metal allergy; were easy to clean; had a natural feel and were esthetic. CONCLUSIONS: GFRCR space maintainers can be a new alternative to the conventional space maintainers used in pediatric dentistry.

Child↗
PubMed1992

[Growth of the graft and astrocytic reaction following transplantation of fetal brain to adult rat's brain. Part II: Cell suspension transplantation into the subarachnoid space].

Suspensions of basal forebrain cells of fetal rats were transplanted into the subarachnoid space of adult rats through a microsyringe needle which was transcortically inserted to the subarachnoid space. Two to 3 months after the transplantation, growth of the graft, neuritic elongation, neovascularization, and astrocytic reaction were examined by Nissl staining, histochemical staining for acethylcholinesterase and Klüver-Barrera's myelin staining, vascular relief images and immunohistochemical staining for laminin, and immunocytochemical staining for glial fibrillary acidic protein (GFAP). Transplanted fetal neurons survived and grew very well over the brain surface and exhibited facilitated neuritic elongation. Several bundles of myelinated fibers linking the subarachnoid and the subpial grafted cells were noticed, but the myelinated fibers penetrating the intact pia mater were not verified. In the grafted tissue, extracellular matrix was formed and a lot of small vessels and capillaries were noticed. Many GFAP-immunoreactive cells were seen in the graft. They had a tendency to gather perivascularly and near the margin of the graft tissue facing subarachnoid space. The subarachnoid space is thought to be an adequate place for transplanted neuronal and glial cells to grow. The subarachnoid space contains the cerebrospinal fluid and also it contacts with rich pial vessels, so that it seems to be superior to the intraparenchymal area in respects of a supply of oxygen and nutrition and of low tissue pressure. Transplanted tissue may be supposed to work as the exocrine and/or endocrine organ which secretes neurotransmitters and their synthetic enzymes and neurotrophic factors. If this is true, it would imply that the subarachnoid space is considered as a promising site for implantation.

Animals↗
PubMedDate not supplied

[A study and follow-up of ten cases of benign enlargement of the subarachnoid spaces].

AIM: To present 10 cases with 'benign enlargement of the subarachnoid spaces' and its clinical and image evolution. PATIENTS AND METHODS: We study 10 patients, 7 boys and 3 girls, because of macrocephaly. It was made a clinic and image follow-up from the first year of age to their cure. In the series, there are two monozygotic twins. RESULTS: The patients had normal head circumference centile at birth, and it was 90 or higher at the age of 5 to 12 months, to keep stabilized, without decreasing, during the time of the study despite disappearing enlargement of the subarachnoid spaces. CT and especially magnetic resonance studies, showed the largest subarachnoid spaces and lateral ventricles between 5 and 12 months of age, and then, a slowly decrease to disappear in a period that was variable among the patients. A moderate enlargement was still found after 5 years of age in some cases. The clinic and image follow-up showed a parallel evolution since birth to 5 years in the pair of homozygous twins. Both showed possible reflux of the cerebrospinal fluid from the subarachnoid spaces to the cerebral ventricles, appearing cyst of the septum pellucidum, possibly due to the increase of the intraventricular pressure. The cyst did not disappear and kept the same size despite disappearing the enlargement of the subdural spaces and the normalization of the ventricular size. Psychomotor evolution has been normal, although most of patients show discrete hypotonus and motor coordination problems, attention deficit and/or hyperactivity. CONCLUSION: Benign enlargement of the subarachnoid spaces has a spontaneous solution, but it can carried out in some cases more slowly than it is though. The disease seems hereditary and the most probable etiology is the difficulty in absorption of the cerebrospinal fluid during the first year of life or still longer. The picture, however, always has a spontaneous solution.

Brain↗
PubMed2005

Worms in space? A model biological dosimeter.

Although it is well known that radiation causes mutational damage, little is known about the biological effects of long-term exposure to radiation in space. Exposure to radiation can result in serious heritable defects in experimental animals, and in humans, susceptibility to cancer, radiation-sickness, and death at high dosages. It is possible to do ground controlled studies of different types of radiation on experimental animals and to physically measure radiation on the space station or on space probes. However, the actual biological affects of long-term exposure to the full range of space radiation have not been studied, and little information is available about the biological consequences of solar flares. Biological systems are not simply passive recording instruments. They respond differently under different conditions, and thus it is important to be able to collect data from a living animal. There are technical difficulties that restrict the placement of an experimental organism in a space environment for long periods of time, in a manner that allows for the recovery of genetic data. Use of the self-fertilizing hermaphroditic nematode, Caenorhabditis elegans offers potential for the design of a biological dosimeter. In this paper, we describe the advantages of this model system and review the literature of C. elegans in space.

Animals↗
PubMed2006

[Bone loss and bone metabolism in astronauts during long-duration space flight].

Significant bone loss is one of the most serious medical concerns during long-duration space flight. This article provides the results of bone loss and bone metabolism obtained from American and Russian long-duration human space flight. Bone loss in astronauts before and after long-duration space flight was evaluated by dual energy X-ray absorptiometry (DXA) and quantitative computed tomography (QCT). DXA revealed bone loss at rates of 0.9%/month in the lumbar spine and 1.5%/month in the femoral neck. QCT revealed cortical, trabecular and integral BMD in the femoral neck at rates of 0.5%/month, 2.5%/month, and 1.5%/month, respectively. Biochemical markers of bone resorption increased during space flight and several months after landing. Bone formation marker was unchanged during space flight, but since 3 weeks after landing it was significantly higher than before flight. A calcium kinetics study confirmed that bone resorption increased, and intestinal calcium absorption decreased during space flight.

Absorptiometry, Photon↗
PubMedDate not supplied

[Genetic aspects of man's adaptation to long-term space flight].

Human genetics may play an important role in medical support of prolonged space flights, which raise serious life sciences questions: what is a normal response or, more specifically, what is norm or pathology. This is a problem of general biology and is related to genetic specificity of every organism. The theoretical basis of pertinent researches is general genetics and cytogenetics with their concepts about the structure and function of the eukaryotic genome. The concept of an individual norm of man's responses is to a certain extent associated with the doctrine of constitutions. From the practical point of view it is suggested to use in space genetics an individual-constitutional approach and the term adaptophenotype (adaptive phenotype) which means a stable complex of genetic and phenotypical characteristics. It can be determined using clinical, genealogical, cytological, and molecular methods, methods of genetic markers, phenotypical analysis, etc. Genetic approaches help reveal not only individual hereditary parameters which manifest as signs but also latent pathological characteristics that may be used for cosmonaut selection. Identification of certain phenotypes of man, i. e. adaptophenotypes, that are suitable for life in space, also means identification of specific genotypes with their response norm at the level of the somatic cell genotype and at the level of a gamete. The role of space genetics is associated with the study of gene, chromosome and population levels of adaptation to long-term space missions. Until recently these levels of adaptation have been neglected. The program of studying human genetics in space proposed here covers both medical aspects and evolutionary approaches.

Adaptation, Physiological↗
PubMed2006

Personal space in schizophrenic patients.

BACKGROUND: Personal space is the area individuals maintain around themselves into which others cannot intrude without arousing discomfort. OBJECTIVE: The purpose of this study was to establish whether schizophrenic patients and mentally healthy adults differ in interpersonal distance preferences according to 1) mental health status 2) experimenter sex 3) approach direction and/or 4) type of disorder. SUBJECTS: 114 patients who met the ICD-10 criteria for schizophrenia and 120 age and gender matching adults with no history of mental illness participated in the study. METHOD: Personal space was assessed using stop-distance technique. All subjects were approached by female and male experimenter from four directions. RESULTS: Personal space zone was significantly larger in the schizophrenic patients than in the comparison group. Subjects in both groups maintained larger interpersonal distances when approached by a male experimenter and when approached frontally. No significant difference in personal space preference was found between subjects manifesting paranoid and residual type of schizophrenia. CONCLUSIONS: The results suggest that schizophrenic patients, presumably due to their mental health, demonstrate a stronger need for personal space. These results are consistent with the protective function of personal space.

Adult↗
PubMed1990

Interrelationships of the pia mater and the perivascular (Virchow-Robin) spaces in the human cerebrum.

Biopsies of histologically normal adult human cerebral cortex, underlying white matter and overlying leptomeninges were taken from frontal and temporal lobectomy specimens excised during the removal of cerebral tumours. Multiple blocks from 6 patients (aged 18-53 years) were examined by light and transmission electron microscopy. A thin sheath of pia mater cells was found to surround completely arterioles and arteries in the brain, in the subpial space and in the subarachnoid space. Pia mater cells, forming the perivascular sheath, were identified by the presence of desmosomes or small nexus junctions and by continuity with the pia mater itself. The presence of the pial sheath suggests that the perivascular spaces around intracerebral arteries are in direct continuity with the perivascular spaces around subarachnoid arteries. No similar pial sheath was observed around intracerebral or subpial venules. The role of the periarterial spaces, enclosed by the pial sheath, is discussed in relation to the results of physiological experiments suggesting drainage of interstitial fluid from brain tissue into the perivascular pathways along major cerebral arteries in the subarachnoid space. As arterioles in the brain become smaller and lose their smooth muscle coats, the pial sheath becomes incomplete. The anatomical relationships between the pia mater and blood vessels in the human cerebrum is summarised diagrammatically, and a possible role for pial cells as an enzymic barrier protecting the brain from exogenous catecholamines is discussed.

Adolescent↗
PubMedDate not supplied

[Localization of lumbar epidural space by loss of resistance and using the Episensor: a comparative study].

Since the existence of negative pressure in the epidural space was reported, its technique of localization has undergone changes directed to improve objectivity, reliability and safety. The aim of the present study was to evaluate a new electronic divide to localize the epidural space, i.e. the Episensor (Palex, Spain). To this end, 71 patients, both males and females, undergoing elective urological surgery and in whom catheterization of the lumbar epidural space had been planned, were prospectively evaluated and randomly assigned to two homogeneous groups. In group I (n = 35) the epidural space was localized by the classical technique of loss of resistance, while in group II the Episensor was used. In both groups several technical parameters, the qualification of the operator and the complications of the procedure were evaluated. There were no significant differences between both groups regarding the quality of epidural blockade or the subjective technical difficulty of the operator. The incidence of complications of the technique of puncture was significantly higher in group II (p less than 0.05); the most common were dura mater puncture in 13 group II patients and in one group I patient (p less than 0.001). There was no correlation between the qualification of the operator and the development of complications. It was concluded that the use of Episensor to localize lumbar epidural space did not improve the effectiveness of blockade but increased the iatrogenic effects of the puncture. Our lack of experience with this new technique and the low negative pressure of lumbar epidural space might have been the causes of the poor results, that we consider as initial in the evaluation of this new method.

Adult↗
PubMed1989

The depth to the epidural space.

Two hundred and ten patients, 145 males and 65 females, aged 20 to 72 years old, ready to receive extracorporeal shock wave lithotripsy under epidural anesthesia were studied to evaluate if any correlation existed between body weight, body surface area, body mass index and body height and the depth to the epidural space. The mean value for the depth to the epidural space was 4.77 +/- 0.55 cm for males, 4.25 +/- 0.55 cm for females and the overall average was 4.61 +/- 0.60 cm. The range of the depth to the epidural space was 3.0-7.0 cm. Linear regression analysis revealed significant correlation between body weight, body surface area, body mass index, body height an the depth to the epidural space, in the order of BW greater than BSA greater than BMI greater than BH. It is concluded that body weight, body surface area, body mass index and body height affect the depth to the epidural space and play an important role in predicting the depth to the epidural space.

Adult↗
PubMed1978

Space control in the primary and mixed dentitions.

Space control has been distinguished from space maintenance. The difference is not a semantic one. Space control calls upon the dentist to apply his knowledge of occlusal development to the patient's condition. It infers assessment and re-evaluation. Space maintenance, unfortunately, sometimes becomes a routine or mechanical placement of appliances. This article has reviewed some of the variables to be considered when effecting space control: the factors that dictate appliance selection and some of the more common appliances used for space control today. No formula has been recommended for the application of appliances. Rather, the dentist has been urged to review the variables and re-evaluate his decisions according to the dynamic development of the patient's dentition.

Acrylic Resins↗