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At least 721 records · Page 40Linked to original sources
PubMed1985

Intercellular spaces in the lymph nodule associated epithelium of the rabbit Peyer's patch and appendix.

Intercellular spaces in the epithelium of the rabbit Peyer's patch and appendix were examined by scanning and transmission electron microscopy to elucidate their three-dimensional structure and their relationship to the reticular spaces in the underlying lymph nodule. Two types of intercellular spaces were distinguished: regularly arranged tubular channels and irregularly winding tunnels. The tubular channels were observed around normal enterocytes on the villi or internodular folds and apical portions of nodule domes. The channel spaces were lined with a successive arrangement of belt-like intercrestal surfaces of prismatic enterocytes and variously sized processes on the crests. The processes adjoining opposed crests formed a ladder-like structure or pectinate septa between neighboring channels. The irregularly winding tunnels were formed among processes of irregularly shaped cells corresponding to FAE cells (Bockman and Cooper, 1973) or M cells (Owen and Jones, 1974) in the nodule associated epithelium. In the appendix, the tunnels were frequently organized into two-story spaces, the adlumenal and basal spaces, which were incompletely separated by cytoplasmic processes. These tunnels continued by pores in the basement membrane to the reticular spaces in the underlying lymph nodules. Furthermore, the tunnels and the basement membrane pores constantly contained single or grouped free cells or their processes. The findings in the present study suggest that the tubular channels are intraepithelial compartments for the absorption of nutrients and fluid, and the irregular tunnels are an intraepithelial network of spaces for the housing of lymphoid cells coming from the underlying lymph nodule.

Animals↗
PubMed2000

STS-95 space experiment for plant growth and development, and auxin polar transport.

The principal objective of the space experiment, BRIC-AUX on STS-95, was the integrated analysis of the growth and development of etiolated pea and maize seedlings in space, and the effect of microgravity conditions in space on auxin polar transport in the segments. Microgravity conditions in space strongly affected the growth and development of etiolated pea and maize seedlings. Etiolated pea and maize seedlings were leaned and curved during space flight, respectively. Finally the growth inhibition of these seedlings was also observed. Roots of some pea seedlings grew toward the aerial space of Plant Growth Chamber. Extensibilities of cell walls of the third internode of etiolated pea epicotyls and the top region of etiolated maize coleoptiles which were germinated and grown under microgravity conditions in space were significantly low. Activities of auxin polar transport in the second internode segments of etiolated pea seedlings and coleoptile segments of etiolated maize seedlings were significantly inhibited and extremely promoted, respectively, under microgravity conditions in space. These results strongly suggest that auxin polar transport as well as the growth and development of plants is controlled under gravity on the earth.

Biological Transport↗
PubMed2001

Separation of DNA by free flow electrophoresis in space.

Free flow electrophoresis of a nematode C. elegans DNA was carried out on the space shuttle flight in International Microgravity Laboratory No. 2 (IML-2)., 1994. We selected the C. elegans DNA as the sample of the space experiment for free flow electrophoresis separation. This worm is a useful animal for the study of development and behavior by genetic analysis, and is a good candidate for a complete DNA sequence analysis because the haploid genome size consists of approximately 100 Mb (megabase) distributed on the six chromosomes, only 1/30 of human genome size. (Recently, the entire genomic DNA (97 Mb) sequences of C. elegans have been completed at the last December, 1998, as the first organism of multicellular system. In addition, many of the genes in C. elegans have extensive similarity to their mammalian counterparts. It may be possible to use the technology of free flow electrophoresis to contribute to the DNA analysis of the eukaryote. In this mission we attempted to make real-time communication between the space shuttle and on the ground during the electrophoresis processing. Because the separation tendency of the sample in space was not predicted so perfectly, the requests to the crews of the space shuttle was needed for selecting the fractions to be separated. According to the three dimensional electropherogram (3DEP) figured out the electrophoresis behavior, we were able to recover those fractions and kept in the deep freezer until landing. This real-time monitoring of the electrophoresis was the first evidence during space electrophoresis experiments which was started at Apollo 14, 1974. Unfortunately, some troubles occurred by contamination of bubbles in space nevertheless the post flight analyses of the fractionated samples were succeeded. The DNAs estimated by the DNA probes were not isolated one but the migration tendencies were differ from each other. It was clear that certain parts of the process in this study are advanced; that is, the precise monitoring of the electrophoresis process in space was accomplished, in real-time, by using 3DEP. In addition, the detection of DNA of recovered samples indicates that all the processes during the study were kept to be free from biological contamination. These results were published in following paper and reviewed in the book.

Animals↗
PubMed1992

CT of the extraperitoneal space: normal anatomy and fluid collections.

Knowledge of the appearance and location of the normal fascial structures surrounding the kidneys and the bladder is the key to proper CT analysis of extraperitoneal fluid collections. Recent studies have shown that the renal fascia and the perirenal space are more complex than previously recognized. An extracapsular renal hematoma, confined against the kidney by the posterior renorenal septum within the perirenal space, can entirely simulate a subcapsular hematoma. Pancreatitis fluid can dissect between the discrete layers that constitute the posterior renal fascia, allowing fluid in the anterior pararenal space to extend posterior to the kidney without directly involving the posterior pararenal space. The umbilicovesical fascia separates the small perivesical space from the potential large reservoir of the prevesical space in the extraperitoneal portion of the pelvis. Fluid in the prevesical space can communicate directly with the retroperitoneal spaces surrounding the kidney. In addition to compartmental localization, CT features of the fluid itself or the presence of ancillary findings such as aortic aneurysm, enlarged pancreas, renal mass, or hydronephrosis will frequently indicate the cause and the extent of most extraperitoneal fluid collections.

Contrast Media↗
PubMed2000

Interword spacing in Chinese text layout.

Three experiments using Chinese text were conducted to investigate word spacing and its effect on reading performance. In Exp. 1, a sonogram detector was used to analyze interword and intercharacter (within a word) time intervals from text read aloud by professional TV broadcasters versus college graduates. The results showed interword intervals were significantly longer than intercharacter intervals, indicating that interword spacing has psychological reality in speech. Exp. 2 examined the effect on reading performance due to separating the characters that compose a word. Separating the characters of a word did not decrease reading accuracy but did result in significantly longer reading times. Exp. 3 explored the effect of word spacing in Chinese sentences on reading performance. Analysis showed that word spacing did not affect reading accuracy, but half character and whole-character spacing significantly reduced reading time. The results of the present study suggest that word spacing in Chinese text layout enhances reading performance. Word spacing may help the reader to segment more quickly a string of characters into words and reduce the likelihood of misinterpretation. Also, ambiguity of sentence structure severely degraded reading accuracy. The implications of the results for word spacing design in Chinese text are discussed.

Adult↗
PubMed1997

Noninvasive optical imaging of the subarachnoid space and cerebrospinal fluid pathways based on near-infrared fluorescence.

The authors have developed a noninvasive optical method to image the subarachnoid space and cerebrospinal fluid pathways in vivo based on the near-infrared fluorescence of indocyanine green (ICG). The ICG was bound to purified lipoproteins (ICG-lipoprotein) and injected into the subarachnoid space of neonatal and adult rats. The ICG fluorescence was detected by a cooled charge-coupled device camera. After injection of ICG-lipoprotein into the cerebral subarachnoid space of the neonatal rat, ICG fluorescence was clearly detected at the injection site through the skull and skin. The ICG fluorescence was observed in the cerebellum and the lumbar spinal cord 1 and 8 hours postinjection, respectively. After injection of ICG-lipoprotein into the lumbar spinal subarachnoid space of an adult rat, ICG fluorescence was observed from the injection site to the thoracic levels along the spinal subarachnoid space. In addition, with the rat's head tilted downward, ICG fluorescence had extended to the cerebral subarachnoid space by 1 hour postinjection. The ICG fluorescence imaging of the cerebral subarachnoid space demonstrated an increase in fluorescence intensity around the lambdoid suture and the forebrain. On dissection of the rat brain the former location was identified as the supracerebellar cistern and the latter as the olfactory cistern. The results of this study are the first to demonstrate that an optical technique is applicable to imaging of the subarachnoid space and cerebrospinal fluid pathways in vivo. In addition, ICG-lipoprotein provides a sensitive optical tracer for imaging extravascular biological structures. Finally, ICG fluorescence imaging does not require an intricate imaging system because ICG is localized near the surface of the body.

Animals↗
PubMed1999

Research on humans during space flights: ethical problems.

Experiments on humans during space flights call for ethical reflection, which is more than a mere assessment of the risks and a concurrent ethical evaluation of manned space flight as such. Although it may be desirable to harmonize ethical standards for international space flights especially against the background of the construction of an International Space Station (ISS) the application of ethical standards for human experiments on earth to the situation in space is not (at all) straight forward. The analysis shows that an ethical evaluation of experiments in space involving humans cannot be made solely on grounds of those principles which apply in comparable cases of terrestrial experiments. The very special conditions in space necessitate further ethical considerations. From this it may of course not be inferred that the current practice of strict ethical evaluation of experiments on humans becomes obsolete once we leave the planet earth. On the contrary, it means that widely accepted principles--like free and informed consent, or data protection and privacy--may need to be amended in order to take proper account of the special conditions in space and the need to achieve a consensus among the different persons involved.

Aerospace Medicine↗
PubMed1996

No evidence of adverse effects on germination, emergence, and fruit yield due to space exposure of tomato seeds.

Seeds of 'Rutgers California Supreme' tomato (Lycopersicon esculentum Mill.) were exposed to outer space conditions aboard the long duration exposure facility (LDEF) satellite in the space exposed experiment developed for students (SEEDS) project of the National Aeronautics and Space Administration (NASA). Seeds aboard the LDEF were packed in dacron bags forming four layers per sealed canister. Some of these seeds were used in Oklahoma and Florida for studies of germination, emergence, and fruit yield. Among all measured variables in three experiments, there was only one significant main effect of canister 2 versus canister 7 (for mean time to germination) and only one main effect of layer (for seedling shoot dry weight). There also were only two inconsistent canister x layer interactions in the germination tests. The contrast of Earth-based control seed versus space-exposed seed was significant four times: in Oklahoma in 1991 the mean time to germination of space-exposed seeds and the days to 50% of final germination were 0.7 days less than for Earth-based seeds, and in Florida in 1992 seedling percent emergence and shoot dry weight were increased by space exposure. Fruit yield and marketability were unaffected in plants grown from space-exposed seeds. These results support student findings from the SEEDS project, and provide evidence that tomato seeds can survive in space for several years without adverse effects on germination, emergence, and fruit yield.

Cosmic Radiation↗
PubMed2001

[Growth and development of plants in a sequence of generations under the conditions of space flight (experiment Greenhouse-3)].

The purpose was to study characteristic features of growth and development of several plant generations in space flight in experiment GREENHOUSE-3 as a part of the Russian-US space research program MIR/NASA in 1997. The experiment consisted of cultivation of Brassica rapa L. in board greenhouse Svet. Two vegetative cycles were fully completed and the third vegetation was terminated on day 13 on the phase of budding. The total duration of the space experiment was 122 days, i.e. same as in the ground controls. In the experiment with Brassica rapa L. viable seeds produced by the first crop were planted in space flight and yielded next crop. Crops raised from the ground and space seeds were found to differ in height and number of buds. Both parameters were lowered in the plants grown from the space seeds. The prime course for smaller size and reduced organogenic potential of plantTs reproductive system seems to be a less content of nutrients in seeds that had matured in the space flight. Experiment GREENHOUSE-3 demonstrated principle feasibility of plant reproduction in space greenhouse from seeds developed in microgravity.

Brassica rapa↗
PubMed2001

[Space radiation biology].

Astronauts were constantly exposed to space radiation containing various kinds of energy with a low-dose rate during long-term stays in space. Therefore, it is important to judge correctly the biological effect of space radiation for human health. In addition, research for space radiation might give us useful information concerning birth and evolution of lives on the earth. Here, we described a view of the future about space experiments at an International Space Station. Therefore, we desire to educate the space researcher of the next generation for importance of research for space radiation.

Cosmic Radiation↗
PubMed2003

Plant-centered biosystems in space environments: technological concepts for developing a plant genetic assessment and control system.

Plants will play an essential role in providing life support for any long-term space exploration or habitation. We are evaluating the feasibility of an adaptable system for measuring the response of plants to any unique space condition and optimizing plant performance under those conditions. The proposed system is based on a unique combination of systems including the rapid advances in the field of plant genomics, microarray technology for measuring gene expression, bioinformatics, gene pathways and networks, physiological measurements in controlled environments, and advances in automation and robotics. The resulting flexible module for monitoring and optimizing plant responses will be able to be inserted as a cassette into a variety of platforms and missions for either experimental or life support purposes. The results from future plant functional genomics projects have great potential to be applied to those plant species most likely to be used in space environments. Eventually, it will be possible to use the plant genetic assessment and control system to optimize the performance of any plant in any space environment. In addition to allowing the effective control of environmental parameters for enhanced plant productivity and other life support functions, the proposed module will also allow the selection or engineering of plants to thrive in specific space environments. The proposed project will advance human exploration of space in the near- and mid-term future on the International Space Station and free-flying satellites and in the far-term for longer duration missions and eventual space habitation.

Agriculture↗
PubMed2004

Animal experiments using mammals are essential to the study on the mechanisms of phenomena produced in the human body in the space environment.

The animal experiments have contributed to the physiology and medicine concerned with the care and cure of patients as well as with an understanding of mechanisms of various diseases and human health. In particular, the numerous mammals have been used for the medical researches. Similarly, to investigate the phenomena in the human body that occur in the space environment, the various mammals have been used for the medical researches in space. Since the human with frontier spirits will never stop continuing the space development and utilization, the space medical and physiological researches using mammals as well as subjects are more important and necessary for the future space activities. The mammal modules in spacecrafts and space station are produced for the rodents at this time. Therefore, from various viewpoints, the rats and mice are the first choice for space mammal experiments of medical or life science researches and space modules for the mammal should be carefully and extensively designed.

Animals↗
PubMed2004

Animal habitats for space experiments.

There has been little opportunity for flight experiments using small animals, due to delay of construction of the International Space Station. Therefore, proposals using small animals have been unfortunately excepted from International Space Life Sciences Experiment application opportunity since 2001. Moreover, NASA has changed their development plan of animal habitats for space experiments according to changes of the U.S. space policy and the outlook is not so bright. However, international researchers have been strongly requesting the opportunity for space experiments using small animals. It will be also important for Japanese researchers to make a request for the opportunity. At the same time, researchers have to make an advance in ground based studies toward space experiments and to respond future application opportunities immediately. In this symposium, we explain the AEM (Animal Enclosure Module), the RAHF (Research Animal Holding Facility), and the AAH (Advanced Animal Habitat). It will be helpful for investigators to have wide knowledge of what space experiment is technically possible. In addition, the sample share program will be introduced into our communities. The program will provide many researchers with the organs and tissues from space-flown animals. We will explain the technical aspect of sample share program.

Animals↗
PubMed1991

[The posterior interparieto-peritoneal or retroperitoneal spaces. 2: Pathological x-ray computed tomographic image].

The old reports about the interparieto-peritoneal spaces described particularly the renal space and its environment. The CT scan has modified the in vivo study of the extraperitoneal spaces (E.P.S.) and brought the question of the acquired knowledge up again. An anatomical research was performed in the first part of this study which describes the structures limited between the parietalis fascia and visceral peritoneal fascias. These are the true EPS which the main element is the propria fascia of Sappey (lateroconal fascia) and its anterior and posterior renal double layers. All these lamellar structures limits spaces variably infiltrated with fat tissue: the anterior pararenal space almost virtual, the posterior pararenal space which continues till the Bogros space and the anterior and posterior renal spaces of the renal compartment which the fat continues till the bladder and accompanies the ureter. The second part of this study precises some notions of general topography which are necessary for reading abnormal CT scan images. This part reminds the aortic and arterial general organization of the vertebrates as described by Mackay. It underlines the architectural importance of the three areas so defined: parietal or peripheral, intermediate or mesoblastic genitourinary and deep lateral or digestive endoblastic. These three areas corresponds to the three vascular aortic circles. It emphasized the importance to accept in practice the notion of visceral joining fascia which has been proved in adult people. The longitudinal architecture of the compartments is precise with respect to their appartenance to one among the three arterial arches of Mackay. What the anatomy suggest, the pathology can prove. Several pathological processes are studied on CT scan: large hemorrhagic or necrotic collections in acute pancreatitis, abnormalities or diseases of renal or adrenal compartments, extraperitoneal mesenchymomas, diseases of the psoas compartment. All these observations are analysed in order to explain anatomical and CT scan findings. This study refers not only to the oldest researches which are still valuable but also to the most recent controversies. All the questions are not solved using the clearest schemes.

Abdomen↗
PubMed1991

[The distribution of solutions in the epidural space].

In 21 patients the distribution within the epidural space of epidurally injected 99mTc-DTPA was assessed. The gamma emissions from the epidural space were measured externally with the patients in supine position by use of a gamma camera. The recordings over the patient's back were stored in digital computer for 60 min. The results were as follows; 1) The spread of the radionuclide was mainly to cephalad direction, and seldom crossed the L5 level to sacral region. 2) The solution injected in the epidural space would distribute to less resistant compartments and the spread depends on the power of injection, negative pressure in the high epidural space and capillary pressure. 3) The elimination half-life of the injected radionuclide was between 1 to 17 min depending on the region in the epidural space. 4) The solution injected in the epidural space may penetrate dura mater at the ink cuff area and local anesthetic agents may affect the spinal nerve roots in the subarachnoid space rather than at the extra-dural space. 5) With continuous infusion technique the diffusion and penetration of the local agent through the dura mater are facilitated and more profound anesthetic effects would be expected. In clinical practice the utilization of the continuous infusion method should be considered along with the bolus injection.

Adult↗
PubMed1990

Making arm movements within different parts of space: dynamic aspects in the primate motor cortex.

The activity of 176 individual cells in the arm area of motor cortex (areas 4 and 6) was studied while monkeys made arm movements of similar direction within different parts of extrapersonal space. The behavioral paradigm used was a 3-dimensional reaction-time task aimed at dissociating the direction of movement, which remained similar across the work space, from the patterns of muscular activity and the angular joint excursions necessary to perform these movements. In agreement with other studies (Georgopoulos et al., 1982; Schwartz et al., 1988), we found that, within a given part of space, the activity of 169 (96.0%) cells studied increased most for a given preferred direction and less for other directions of movement. This change was graded in an orderly fashion. We further analyzed the orientation in space of the cells' preferred directions under the differing conditions of the task. We found that, as movements with similar trajectories were made within different parts of space, the cells' preferred directions changed spatial orientation. This change was of different magnitudes for different cells, but at the level of the population, it followed closely the changes in orientation of the arm necessary to perform the movements required by the task. Movement population vectors (Georgopoulos et al., 1983, 1986, 1988) computed from cell activity proved to be good predictors of movement direction regardless of where in space the movements were performed. These results indicate that motor cortical cells can code direction of movement in a way which is dependent on the position of the arm in space. The data are discussed in relation to the existence of mechanisms which facilitate the transformation between extrinsic and intrinsic coordinates. These transformations are necessary to perform arm movements to visual targets in space.

Animals↗
PubMed1989

Soviet space flight: the human element.

Building on past experience and knowledge, the Soviet manned space flight effort has become broad, comprehensive, and forward-looking. Their long-running space station program has provided the capabilities to investigate long-term effects of microgravity on human physiology and behavior, and test various countermeasures against microgravity-induced physiological deconditioning. Since the beginning of Soviet manned space flight, the biomedical training and preparation of cosmonauts has evolved from a process that increased human tolerance to space flight factors, to a system of interrelated measures to prepare cosmonauts physically and psychologically to live and work in space. Currently, the Soviet Union is constructing a multimodular space station, the Mir. With the emergence of dedicated laboratory modules, the Soviets have begun the transition from small-scale experimental research to large-scale production activities and specialized scientific work in space. In the future, additional laboratory modules will be added, including one dedicated to biomedical research, called the "Medilab." The longest manned space flight to date (326 d) has been completed by the Soviets. The biomedical effects of previous long-duration flights, and perhaps those of still greater length, may contribute important insight into the possibility of extended missions beyond Earth, such as a voyage to Mars.

Adaptation, Physiological↗
PubMed1986

Space: exploration-exploitation and the role of man.

The early years of space activity have emphasized a crew role similar to that of the test pilot or the crew of a high performance aircraft; even the Apollo lunar exploration missions were dominated by the task of getting to and from the moon. Skylab was a prototype space station and began to indicate the range of other functional roles man will play in space. The operation of the Space Shuttle has the elements of the operation of any other high performance flight vehicle during launch and landing; but in its on-orbit operations, it is often a surrogate space station, developing techniques and demonstrating the role of a future space station in various functions. In future space systems, the role of the crew will encompass all of the activities pursued in research laboratories, manufacturing facilities, maintenance shops, and construction sites. The challenge will be to design the tasks and the tools so that the full benefit of the opportunities offered by performing these functions in space can be attained.

Humans↗