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PubMedDate not supplied

Cartilage space width in slipped capital femoral epiphysis: the relationship to cartilage necrosis.

The radiolucent cartilage space of eighty-three patients with unilateral or bilateral slipped capital femoral epiphysis was measured by a standardized technique. In the majority of patients, whether unilateral or bilateral involvement, there was bilateral narrowing of the cartilage space. In the unaffected hip of unilaterally involved patients, there was a progressive narrowing as skeletal maturity was attained. A concomitant anatomical study of cadaver hips, removed at autopsy from adolescent patients, showed a progressive narrowing of the cartilage as the proximal femur matured. Black females showed most narrowing (minimum cartilage space width), had the narrowest final cartilage space widths, and took the longest to attain this final width. While other racial, sexual and therapeutic groups failed to demonstrate statistically significant differences, the general trend was for females, Blacks, and patients treated by osteotomy to have more joint space narrowing. However, rewidening occurred in most of these affected joint spaces, in contrast to the progressive linear decrease observed in unaffected hips and anatomical specimens. On the basis of this study, we feel that cartilage space narrowing may be anticipated in the post-operative period in most patients treated for slipped capital femoral epiphysis. This narrowing appears to improve with time. Narrowing of greater than one-half the original width, in association with pain and limitation of joint function, probably represents "cartilage necrosis," or pathologic joint space narrowing. Unless the narrowing remains less than one-half to two-thirds of the initial cartilage space for more than twenty-four to thirty-six months, probably no specific surgical treatment should be undertaken, other than observation and protected weight bearing during any painful phase. Plotting the roentgenographic cartilage space width during the three month to thirty-six month phase may be useful in monitoring and predicting the outcome.

Adolescent↗
PubMed2003

Mirror apraxia affects the peripersonal mirror space. A combined lesion and cerebral activation study.

Mirror apraxia is a condition in which patients with lesions of the posterior parietal cortex have deficits in reaching to objects presented through a mirror. The aim of the present study was to investigate possible mechanisms underlying this disorder. First, we addressed the question of whether mirror apraxia is exhibited to the same extent in peripersonal and in body space. Four patients with lesions of the posterior parietal lobe on either side and with marked mirror apraxia were required to reach for objects that were presented to them through a mirror and located either in body space (i.e. on the body surface) or in peripersonal space (i.e. in the reaching distance). Whereas reaching for objects located in body space was flawless in all patients, the performance deteriorated when the same objects were transferred to the peripersonal space. Although the objects were located only a few centimetres above the body surface, the patients reached towards the virtual object in the mirror. Based on these results we suggest that mirror apraxia may originate from a dissociation between the representations of body schema and peripersonal space and that objects located on the body surface become integrated into the body schema. In the second part of the study, using positron emission tomography study (PET), we studied the cerebral activation pattern during reaching to objects presented through a mirror in the peripersonal space in healthy subjects. The results show that increased neural activity in the anterior part of the intraparietal sulcus and in the dorsal premotor cortex was bound to the transformation of the target position from the mirror space to the real space. In contrast, the activity related to object localization in the mirror occurred at the parieto-occipital junction. Both mirror and arm transformation involved the medial posterior part of the superior parietal lobule, putatively area V6a. The results demonstrate that acting through a mirror is processed in a number of cortical areas of the dorsal stream.

Aged↗
PubMedDate not supplied

Evaluation of NASA Foodbars as a standard diet for use in short-term rodent space flight studies.

OBJECTIVES: [corrected] A standard rodent diet for space flight must meet the unique conditions imposed by the space environment and must be nutritionally adequate because diet can influence the outcome of experiments. We evaluated the use of National Aeronautics and Space Administration (NASA) Foodbars as a standard space flight diet for rats. METHODS: The Foodbar's semi-purified formulation permitted criteria such as nutrient consistency, high nutrient bioavailability, and flexibility of formulation to be met. Extrusion of the semi-purified diet produced Foodbars with the proper texture and a non-crumbing solid form for use in space. Treatment of Foodbar with 0.1% potassium sorbate prevented mold growth. Irradiation (15 to 25 kGy) prevented bacterial growth and, in combination with sorbate treatment, added protection against mold for shelf stability. RESULTS: During the development process, nutrient analyses indicated that extrusion and irradiation produces nutrient losses. Nutrients were adjusted accordingly to compensate for processing losses. Nutrient analysis of Foodbars continues to be performed routinely to monitor nutrient levels. It is important that the standard rodent diet provide nutrients that will prevent deficiency but also avoid excess that may mask physiologic changes produced by space flight. All vitamin levels in the Foodbars, except for vitamin K, conformed to or exceeded the current National Research Council (NRC) 1995 recommendations. All indispensable amino acids in Foodbar conformed to or exceeded the NRC nutrient recommendation for mouse growth and rat maintenance. However, some indispensable amino acids were slightly below recommendations for rat reproduction and growth. Short-term (18 to 20 d) animal feeding studies indicated that Foodbars are palatable, support growth, and maintain health in rats. CONCLUSIONS: Results indicated that NASA Rodent Foodbars meet the physical and nutritional criteria required to support rodents in the space environment and thus may be used successfully as a standard diet for short-term space flight studies. However, the nutritional adequacy of NASA Rodent Foodbars as a standard diet on longer-duration (>20 d) space flight missions remains to be determined.

Amino Acids↗
PubMed1998

Neurobiological problems in long-term deep space flights.

Future missions in space may involve long-term travel beyond the magnetic field of the Earth, subjecting astronauts to radiation hazards posed by solar flares and galactic cosmic rays, altered gravitation fields and physiological stress. Thus, it is critical to determine if there will be any reversible or irreversible, detrimental neurological effects from this prolonged exposure to space. A question of particular importance focuses on the long-term effects of the space environment on the central nervous system (CNS) neuroplasticity, with the potential acute and/or delayed effects that such perturbations might entail. Although the short-term effects of microgravity on neural control were studied on previous low earth orbit missions, the late consequences of stress in space, microgravity and space radiation have not been addressed sufficiently at the molecular, cellular and tissue levels. The possibility that space flight factors can interact influencing the neuroplastic response in the CNS looms critical issue not only to understand the ontogeny of the CNS and its functional integrity, but also, ultimately the performance of astronauts in extended space forays. The purpose of this paper is to review the neurobiological modifications that occur in the CNS exposed to the space environment, and its potential consequences for extended deep space flight.

Adaptation, Physiological↗
PubMed2003

Functional representation of 3D space in endogenous attention shifts.

The aim of this study was to explore whether the attentional system, as far as an endogenous orienting is concerned, allocates resources along the sagittal plane and whether such a process is affected by, and is likely to be based on, different functional representations of 3D space in the brain. Several models make a main action-based distinction between representations of peripersonal space and of those extrapersonal space. Accordingly, if attention has to move from one representation to another, it should be possible to observe a decrease in performance during such a transition. To test this hypothesis three experiments were run in which participants performed a cued detection task. Cue stimuli were informative and were centrally located around the fixation point. Target stimuli were displayed at four different depth planes. In the first experiment, assuming that the border between the peripersonal space and the extrapersonal space was at 1 m from the observer, half the target stimuli were located in the peripersonal space and half in the extrapersonal space. The fixation point was located at 1 m from the observer. In the second experiment, the fixation point was moved at 2 m from the observer in order to rule out the possible effects of ocular motor programming. In the third experiment, in order to rule out effects related to the spatial layout of target stimuli (i.e., centre of mass effect) two target stimuli were located in the peripersonal space and six in the extrapersonal space. In all the experiments, besides a validity effect, we observed greater reaction times when attention shift was across spatial representations than when it was within the same representation. The implications for action-oriented models of attention are discussed.

Adult↗
PubMed1997

[Squirrel monkey--an ideal primate (correction of prmate) model of space physiology].

Investigation of the vestibulo-ocular system of the squirrel monkey was reviewed in consideration of space motion sickness (SMS), or which is recently more often termed as space adaptation syndrome (SAS). Since the first launching of the space satellite, Sputnik [correction of Sputonik] in October 1957, many experiments were carried out in biological and medical fields. A various kind of creatures were used as experimental models from protozoa to human beings. Rats and monkeys are most favorite animals, particularly the non-human primate seems to be the one, because of its phylogenetic relatives akin to the human beings. Chimpanzees, rhesus monkeys, pig tailed-monkeys, red-faced monkeys and squirrel monkeys have been used mostly in American space experiments. Russian used rhesus monkeys. Among these, however, the squirrel monkey has an advantage of the small size of the body, ranging from 600- l000g in adult. This small size as a primate is very advantageous in experiments conducted in a narrow room of the space satellite or shuttle because of its space-saving. The squirrel monkey has another advantage to rear easily as is demonstrated to keep it as a pet. Accordingly, this petit animal provides us a good animal model in biological and medical experiments in space craft. The size of the brain of the squirrel monkey is extraordinary large relative to the body size, which is even superior to that of the human beings. This is partly owed to enlargement of the occipito-temporal cortices, which are forced to well develop for processing a huge amount of audio-visual information indispensable to the arboreal habitant to survive in tropical forest. The vestibular system of the squirrel monkey seems to be the most superior as well, when judged from it relative size of the vestibular nuclear complex. Balancing on swinging twigs or jumping from tree to tree developed the capability of this equilibrium system. Fernandez, Goldberg and his collaborators used the squirrel monkey to elucidate functions of the peripheral vestibular system. A transfer function was proposed to explain the behaviors of regular and irregular unit activity of vestibular nerve fibers. The physiologic characteristics of the second order vestibular neuron was investigated in combination of electrophysiological and micro-morphological way, with using WGA-HRP methods, in relation to somato-motor and eye movements. Interconnections between vestibular neurons and cerebellum, interstitial nucleus of Cajal, oculomotor nuclear complex, superior colliculus and cervical spinal cord were elucidated. In physiological field of the vestibular system, the vestibulo-ocular reflex is well studied and results obtained from the squirrel monkey experiments were reviewed. The squirrel monkey, particularly the Bolivian, is a unique animal in that it is vulnerable to motion sickness induced by visual-motion stimulation with phase mismatch of the two stimuli. Experimental results of labyrinthectomy or bilateral ablation of the maculae staticae led to the conclusion that both semicircular and otolith organs are involved in the genesis of space motion sickness. On the other hand, destruction of the area postrema, acknowledged as the vomiting center to chemical stimulants, produced controversial results. However, it must be pointed out that the a human subject underwent to resection of the area postrema, became insensitive to administration of apomorphine, a well known chemical stimulant of vomiting. Finally the experiments in space revealed the presence of at least two origins of caloric nystagmus, that is, attributable to convection and non-convection current of the endolymphatic fluid.

Acoustic Maculae↗
PubMed2005

[Engineering issues of microbial ecology in space agriculture].

Closure of the materials recycle loop for water-foods-oxygen is the primary purpose of space agriculture on Mars and Moon. A microbial ecological system takes a part of agriculture to process our metabolic excreta and inedible biomass and convert them to nutrients and soil substrate for cultivating plants. If we extend the purpose of space agriculture to the creation and control of a healthy and pleasant living environment, we should realize that our human body should not be sterilized but exposed to the appropriate microbial environment. We are proposing a use of hyper-thermophilic aerobic composting microbial ecology in space agriculture. Japan has a broad historical and cultural background on this subject. There had been agriculture that drove a closed loop of materials between consuming cities and farming villages in vicinity. Recent environmental problems regarding garbage collection and processing in towns have motivated home electronics companies to innovate "garbage composting" machines with bacterial technology. Based on those matured technology, together with new insights on microbiology and microbial ecology, we have been developing a conceptual design of space agriculture on Moon and Mars. There are several issues to be answered in order to prove effectiveness of the use of microbial systems in space. 1) Can the recycled nutrients, processed by the hyper-thermal aerobic composting microbial ecology, be formed in the physical and chemical state or configuration, with which plants can uptake those nutrients? A possibility of removing any major components of fertilizer from its recycle loop is another item to be evaluated. 2) What are the merits of forming soil microbial ecology around the root system of plants? This might be the most crucial question. Recent researches exhibit various mutually beneficial relationships among soil microbiota and plants, and symbiotic ecology in composting bacteria. It is essential to understand those features, and define how to conduct preventive maintenance for keeping cultivating soil healthy and productive. 3) Does microbial ecology contribute to building sustainable and expandable human habitation by utilizing the on site extraterrestrial resources? We are assessing technical feasibility of converting regolith to farming soil and structural materials for space agriculture. In the case of Mars habitation, carbon dioxide and a trace amount of nitrogen in atmosphere, and potassium and phosphor in minerals are the sources we consider. Excess oxygen can be accumulated by woods cultivation and their use for lumber. 4) Is the operation of space agriculture robust and safe, if it adopts hyper-thermophilic aerobic microbial ecology? Any ecological system is complex and non-linear, and shows latency and memory effects in its response. It is highly important to understand those features to design and operate space agriculture without falling into the fatal failure. Assessment should be made on the microbial safety and preparation of the preventive measures to eliminate negative elements that would either retard agricultural production or harm the healthy environment. It is worth to mention that such space agriculture would be an effective engineering testbed to solve the global problem on energy and environment. Mars and Moon exploration itself is a good advocate of healthy curiosity expressed by the sustainable civilization of our humankind. We propose to work together towards Mars and Moon with microbial ecology to assure pleasant habitation there.

Agriculture↗
PubMed1998

Psychiatric issues affecting long duration space missions.

BACKGROUND: As we move into the next Millennium, increasing numbers of people will travel into space. Psychological screening methods will be relaxed on near-Earth missions, such as might occur on a space station or a lunar colony. Crewmembers on interplanetary missions such as a trip to Mars will have to deal with psychiatric problems themselves with no possibility of evacuating an affected individual. For these reasons, it is important for support personnel on Earth and crewmembers in space to be knowledgeable about psychiatric difficulties that might occur and their appropriate treatments. METHODS: Anecdotal reports from long duration manned space missions and studies from space analog environments on Earth were reviewed for information concerning these issues. RESULTS: Psychiatric problems pertinent to the space environment include adjustment and psychosomatic reactions, asthenia, mood and thought disorders, and post-mission personality changes and family problems. Counter-measures to ameliorate these difficulties involve pre-launch selection and training; monitoring, support, and counseling/psychotherapy during the mission; and post-return debriefings with crew members and their families. Psychoactive medications have been useful during space missions, although unclear pharmacokinetic issues related to microgravity need to be taken into account. CONCLUSION: Although much is known about psychiatric issues related to long duration manned space travel, more empirical work needs to be done during actual space missions.

Anecdotes as Topic↗
PubMedDate not supplied

A k nearest neighbour test for space-time interaction.

This paper describes a k nearest neighbour statistic sensitive to the pattern of cases expected of space-time clusters of health events. The Knox and Mantel tests are frequently used for space-time clustering but have two disadvantages. First, the selection of critical space-time distances for the Knox test and of a data transformation for the Mantel test is subjective. Second, the Mantel statistic is the sum of the products of space and time distances, is linear in form, and is not sensitive to non-linear associations between small space and time distances expected of contagious processes. The k nearest neighbour statistic is the number of case pairs that are k nearest neighbours in both space and time, and is evaluated under the null hypothesis of independent space and time nearest neighbour relationships. The test was applied to simulated and real data and compared to the Knox and Mantel tests using statistical power comparisons. The k nearest neighbour test proved sensitive to the space-time interaction pattern expected of disease clusters, does not require parameters (such as critical distances) to be estimated from the data, and may be used to test hypotheses about the spatial and temporal scale of the cluster process. The method addresses significant weaknesses in existing space-time cluster tests and should prove useful in the quantification and evaluation of clusters of human health events. Additional research is needed to further document the power of the test under different cluster processes.

Censuses↗
PubMed1992

Role of vestibular and neck inputs for the perception of object motion in space.

UNLABELLED: The contribution of vestibular and neck inputs to the perception of visual object motion in space was studied in the absence of a visual background (in the dark) in normal human subjects (Ss). Measures of these contributions were obtained by means of a closed loop nulling procedure; Ss fixed their eyes on a luminous spot (object) and nulled its actual or apparent motion in space during head rotation in space (vestibular stimulus) and/or trunk rotation relative to the head (neck stimulus) with the help of a joystick. Vestibular and neck contributions were expressed in terms of gain and phase with respect to the visuo-oculomotor/joystick feedback loop which was assumed to have almost ideal transfer characteristics. The stimuli were applied as sinusoidal rotations in the horizontal plane (f = 0.025-0.8 Hz; peak angular displacements, 1-16 degrees). RESULTS: (1) During vestibular stimulation, Ss perceived the object, when kept in fixed alignment with the moving body, as moving in space. However, they underestimated the object motion; the gain was only about 0.7 at 0.2-0.8 Hz and clearly decreased at lower stimulus frequencies, while the phase exhibited a small lead. (2) During pure neck stimulation (trunk rotating relative to the stationary head), the object, when stationary, appeared to move in space counter to the trunk excursion. This neck-contingent object motion illusion was small at 0.2-0.8 Hz, but increased considerably with decreasing frequency, while its phase developed a small lag. (3) Vestibular, neck, and visuo-oculomotor effects summed linearly during combined stimulations. (4) The erroneous vestibular and neck contributions to the object motion perception were complementary to each other, and the perception became about veridical (G approximately 1, phi approximately 0 degree), when both inputs were combined during head rotation with the trunk stationary. The results are simulated by an extended version of a computer model that previously had been developed to describe vestibular and neck effects on human perception of head motion in space. In the model, the perception of object motion in space is derived from the superposition of three signals, representing "object to head" (visuo-oculomotor; head coordinates), "head on trunk" (neck; trunk coordinates), and "trunk in space" (vestibular-neck interaction; space coordinates).

Humans↗
PubMed1975

The role of the lateral intercellular spaces in the control of ion permeation across the rabbit gall bladder.

Diffusion potentials and conducatance measurements were used to evaluate the changes in permeability of the rabbit gall bladder when the lateral spaces were 1) closed by the addition of sucrose to the mucosal fluid, and 2) dilated by the addition of sucrose to the serosal fluid. The results showed that when the lateral spaces were closed (less than 10 nm/ 1) there was a significant decrease in the conductance of the epithelium, and 2) the ion selectivity of the epithelium moved towards the free solution sequence. The conductance decreased from 31 to 13 mmhos/cm2, and the selectivety changed from Na(1) greater than Li(0.92) greater than Cs(0.85) to Cs(1.27) greater than Na(1) greater than Li(0.84). Neither dilation of the spaces to greater than 1.5 mum nor addition of sucrose to both sides of the gall bladder changed the conductance or the ion selectivity. These results are consistant with the hypothesis that in the gall bladder the major barrier to ion permeation across the epithelium lies in 1) the tight junctions, when the lateral spaces are dilated, 2) the lateral spaces when the spaces are collapsed, and 3) a combination of both the spaces and the junctions when the spaces are reduced much below 0.5 mum. Consequently the status of the lateral intercellular spaces has to be taken into account when assessing the mechanisms of ion permeation across low resistance epithelia.

Animals↗
PubMed2004

Creation of biological module for self-regulating ecological system by the way of polymerization of composite materials in free space.

The large-size frame of space ship and space station can be created with the use of the technology of the polymerization of fiber-filled composites and a liquid reactionable matrix applied in free space or on the other space body when the space ship or space station will be used during a long period of time. For the polymerization of the station frame the fabric impregnated with a long-life polymer matrix (prepreg) is prepared in terrestrial conditions and, after folding, can be shipped in a compact container to orbit and kept folded on board the station. In due time the prepreg is carried out into free space and unfolded. Then a reaction of matrix polymerization starts. After reaction of polymerization the durable frame is ready for exploitation. After that, the frame can be filled out with air, the apparatus and life support systems. The technology can be used for creation of biological frame as element of self regulating ecological system, and for creation of technological frame which can be used for a production of new materials on Earth orbit in microgravity conditions and on other space bodies (Mars, Moon, asteroids) for unique high price mineral extraction. Based on such technology a future space base on Earth orbit with volume of 10(6) m3 and a crew of 100 astronauts is considered.

Ecological Systems, Closed↗
PubMed2005

Shaping multisensory action-space with tools: evidence from patients with cross-modal extinction.

Recent findings from neurophysiology, neuropsychology and psychology have shown that peri-personal space is represented through an integrated multisensory processing. In humans, the interaction between peri-personal space representation and action execution can be revealed through the use of tools that, by extending the reachable space, modify the strength of visual-tactile extinction. We have previously shown that the peri-hand space whereby vision and touch are integrated can be expanded, and contracted, depending upon tool-use. Here, we show that these dynamic changes critically depend upon active tool-use, as they are not found after an equally long, but passive exposure to an elongated (hand+tool) body configuration. We also show that the extent of the peri-hand space elongation, as assessed at fixed far location (60 cm from the hand), varies according to the tool length such that a 30 cm long tool produced less elongation than a 60 cm long tool. This reveals for the first time that the distal border of elongated area is not sharply limited to the tool length, but extends beyond its physical size to include a peri-tool space whereby the strength of visual-tactile integration seems to fade. Remarkably, a similar amount of peri-hand space elongation was found when the effects of using a 30 cm long tool were compared with those produced by using a tool that was physically 60 cm long, but operationally 30 cm long. By dissociating with this 'hybrid' tool, the amount of space that is globally added to the hand (60 cm) from the one that is actually reachable (30 cm), we provide here the first evidence that the extent of peri-hand space elongation after tool use is tightly related to the functionally effective length of the tool, and not merely to its absolute length.

Adult↗
PubMed1998

Terrestrial and space-grown HAP and OCP crystals: effect of growth conditions on perfection and morphology.

This paper reports comparative characterizations of calcium phosphate crystals grown on earth and in space. At the CaCl2 and KH2PO4 + K2HPO4 solution concentrations and the pH used, only hydroxyapatite (HAP) crystals grow under terrestrial condition while both HAP and octacalcium phosphate (OCP) crystals grew during the space experiment. The space-grown OCP crystals reach 3 mm in size, the space-grown HAP crystals reach sizes up to 100 times larger than the earth-grown crystallites. It was found also that the space-grown crystallites are more perfect than the terrestrial ones, being more stable under electron beam during HRTEM examination. Spherolites of hydroxyapatite consist of small and thin HAP crystals with different orientations. Space-grown OCP crystals containing almost pure OCP phase show strong striations along the c direction due to thickness variations. Terrestrial OCP crystals grown at lowest supersaturation on earth may be almost as large as the space-grown ones, possess a regular habit and are homogeneous in thickness. However, they always contain substantial regions of HAP structure. Also, in these crystals electron irradiation induces phase transformation from crystalline to amorphous (disordered) state during transmission electron microscopy observations. In the space-grown crystals, such transformation needs longer radiation time. We believe that the differences described above come from much lower supersaturation and different pH for crystals nucleating and growing in space compared to those formed on earth.

Calcium Phosphates↗
PubMed2001

Large-size space laboratory for biological orbit experiments.

The study of space factors on living systems has great interest and long-term experiments during orbital flight will be important tool for increasing our knowledge. Realization of such experiments is limited by constraints of modern space stations. A new technology of large-size space laboratory for biological experiments has been developed on the basis of polymerization techniques. Using this technique there are no limits of form and size of laboratory for a space station that will permit long term experiments on Earth orbit with plants and animals in sufficient volume for creation of closed self-regulating ecological systems. The technology is based on experiments of the behavior of polymer materials in simulated free space conditions during the reaction of polymerization. The influences of space vacuum, sharp temperature changes and space plasma generated by galactic rays and Sun irradiation on chemical reaction were evaluated in their impact on liquid organic materials in laboratory conditions. The results of our study shows, that the chemical reaction is sensitive to such space factors. But we believe that the technology of polymerization could be used for the creation of space biological laboratories in Earth orbit in the near future.

Cosmic Radiation↗
PubMed2004

Periodic structures and diurnal variation in blood pressure and heart rate in relation to microgravity on space station MIR.

Four Russian crew members were studied on space station MIR, and blood pressure (BP) and heart rate (HR) data were continuously collected. BP and HR data were collected on earth 1 day before orbital flight to the space station, then at weeks 8, 16 and 24 during space flight, and again 1 or 2 days after returning to earth. Time serial data for BP and HR were analyzed by spectral analysis with the MemCalc system (Suwa Trust, Sapporo, Japan). Periodic structures of diurnal variation in systolic blood pressure (SBP), diastolic blood pressure (DBP) and HR were compared at 24-hour, 12-hour and 8-hour intervals, these being determined as the main periodic components for the assessment of BP and HR variability. The 24-h mean levels of SBP and HR during space flight were unchanged. Waking SBP was not different from pre-flight values. During sleep, in-flight changes in HR did not differ from pre-flight values. SBP during sleep in orbit increased to over pre-flight values. Waking DBP was reduced during flight. The SBP and HR phases over a 24-hour cycle were shortened with a more pronounced shortening in weeks 8 and 16 compared with pre-flight values, and at week 24 recovered to preflight values. The 12, 8-hour-cycle remained unchanged, and were similar to pre-flight values. At the space station, the astronauts' mission was carried out under strict control of sleeping and waking hours; therefore, their 24-hour schedule is an artificially constructed situation. Main periodicity structures were maintained by strict control of lifestyle during long-term space flight. The conclusions reached were as follows: 1) SBP levels during sleep in a space environment increased compared with those on earth; 2) the periodicity phase of BP and HR shifted toward to 24-hour cycle as a result of long-term space flight, even though these periods shortened after a few months compared with pre-space flight values.

Adult↗
PubMed2002

Microgravity and immune responsiveness: implications for space travel.

To date, several hundred cosmonauts and astronauts have flown in space, yet knowledge about the adaptation of their immune system to space flight is rather limited. It is evident that a variety of immune parameters are changed during and after space flight, but the magnitude and pattern of these changes can differ dramatically between missions and even between crew members on the same mission. A literature search was conducted involving a total of 335 papers published between 1972 and 2002 that dealt with the key words immune response, microgravity and astronauts/cosmonauts, isolation, gravity, and human health. The data from multiple studies suggested that major discrepancies in outcome are due to methodologic differences. However, the data also suggested major factors that affect and modulate the immune response during space travel. In part at least, these discrepancies can be attributed to methodologic differences. In addition, a variety of other features, in particular the types and extent of stressors encountered during space missions, are likely to contribute to the variability of immune responses during and after space flight. That stress plays an important role in the effects of space flight on immunologic parameters is suggested by the frequent findings that stress hormones are upregulated during and after space flight. Unfortunately, however, the existing data on hormonal parameters are almost as varied as those on immunologic changes, and correlations between the two datasets have only rarely been attempted. The functional implications of space flight-induced alterations in immune response largely remain to be elucidated, but the data suggest that long-term travel will be associated with the development of immune-compromised hosts.

Adaptation, Physiological↗
PubMed1998

Skin to cervical epidural space distances as read from magnetic resonance imaging films: consideration of the "hump pad.".

STUDY OBJECTIVE: To measure the distances from the skin to the epidural space (DSES) of the lower cervical and upper thoracic intervertebral spaces. DESIGN: Retrospective review of films of the cervical spine as obtained by magnetic resonance imaging (MRI). SETTING: Health care facility that provides diagnosis and treatment of patients with chronic pain. MEASUREMENTS AND MAIN RESULTS: MRI sagittal films of 100 patients, who had diagnostic studies for chronic headaches and cervicobrachial radiculopathy, were reviewed. Measurements were made of DSES, the dural sac, and the spinal cord by centimeter ruler. Estimates were also made of the width of the epidural space by measuring the distance from the ligamentum flavum to the dural sac. The longest DSES were noted at C6-7 and C7-T1 levels, with a mean of 5.7 cm, but they decreased to a mean of 5.4 cm at the T1-2, and to 4. 7 cm at the T2-3 intervertebral spaces. One of the major factors in this variability was the presence of an accumulation of fatty tissue along the lower cervical and upper thoracic area, which the authors named the "hump pad." This accumulation appears to be thicker in obese patients, with a slight correlation coefficient with the patient's weight. The distances from ligamentum flavum to dural sac, representing the depth of the epidural space, averaged 0.3 cm, 0.4 cm, 0.5 cm, and 0.4 cm, respectively. CONCLUSIONS: In the cervical spine, DSES varies from space to space. In obese individuals, the fat pad may increase DSES at the lower cervical intervertebral spaces. The longest mean distances from the ligamentum flavum to the dural sac and to the spinal cord were found at the T1-2 and T2-3 levels, precisely where DSES is shorter. All things being equal, the upper thoracic intervertebral spaces appeared to provide a greater margin of safety for insertion of epidural catheters to treat cervicobrachial radiculopathies.

Adipose Tissue↗