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971.
The influence of ionizing radiation (gamma-rays 60Co) on aggregation activity of the vascular wall and functional (aggregation) platelet activity was studied in the course of the development of acute radiation sickness. The decrease in the aggregation properties of the vascular wall and high functional activity of platelets were inversely proportional, correlating with the periods of acute radiation sickness development and depending on the radiation dose. It is suggested that the changes detected may play a role in the pathogenesis of the development of the postirradiation thrombohemorrhagic syndrome. 相似文献
972.
In continuously stirred tank reactor experiments, with manure as substrate at thermophilic temperatures, the use of volatile fatty acids (VFA) as process indicators was investigated. Changes in VFA level were shown to be a good parameter for indicating process instability. The VFA were evaluated according to their relative changes caused by changes in hydraulic loading, organic loading or temperature. Butyrate and isobutyrate together were found to be particularly good indicators. Butyrate and isobutyrate concentrations increased significantly 1 or 2 days after the imposed perturbation, which makes these acids suitable for process monitoring and important for process control of the anaerobic biological system. In addition it was shown in a batch experiment that VFA at concentrations up to 50 mM did not reduce the overall methane production rate. This showed that VFA accumulation in anaerobic reactors was the result of process imbalance, not the cause of inhibition, thus justifying the use of VFA as process indicators. 相似文献
973.
M A Taylor K A Pratt D F Revell K C Baker I G Sumner P W Goodenough 《Protein engineering》1992,5(5):455-459
For the first time the pro-form of a recombinant cysteine proteinase has been expressed at a high level in Escherichia coli. This inactive precursor can subsequently be processed to yield active enzyme. Sufficient protein can be produced using this system for X-ray crystallographic structure studies of engineered proteinases. A cDNA clone encoding propapain, a precursor of the papaya proteinase, papain, was expressed in E. coli using a T7 polymerase expression system. Insoluble recombinant protein was solubilized in 6 M guanidine hydrochloride and 10 mM dithiothreitol, at pH 8.6. A protein-glutathione mixed disulphide was formed by dilution into oxidized glutathione and 6 M GuHCl, also at pH 8.6. Final refolding and disulphide bond formation was induced by dilution into 3 mM cysteine at pH 8.6. Renatured propapain was processed to active papain at pH 4.0 in the presence of excess cysteine. Final processing could be inhibited by the specific cysteine proteinase inhibitors E64 and leupeptin, but not by pepstatin, PMSF or EDTA. This indicates that final processing was due to a cysteine proteinase and suggests that an autocatalytic event is required for papain maturation. 相似文献
974.
N V Naryzhnaia L N Maslov Iu G Revinskaia Iu B Lishmanov 《Uspekhi fiziologicheskikh nauk》2001,32(4):73-81
The present paper has analyzed relationship between sympatico-adrenal and opioid systems in the pathogenesis of stress heart damage. Based on the our own results and other investigator data the authors make a conclusion that namely relationship between opioid and sympatico-adrenal systems both on the level of the brain and on the periphery determines a degree of the heart resistance to the injury action of severe stress. Myocardial protection by opioids at stress was found to be mediated by the peripheral mu-opioid receptors and was associated with decrease in an activity of sympatico-adrenal system and a inhibition of its effector part. On contrary central opioid system activation leads to an increase in stress heart damage via an increase in sympathetical influence on the myocardium. 相似文献
975.
The lagena (the third otolith endorgan in vertebrates) 总被引:1,自引:1,他引:0
V. I. Khorevin 《Neurophysiology》2008,40(2):142-159
In this review, the structure and functions of the lagena (the third otolith organ) in an evolutionary lineage of the vertebrates
are described and discussed. The lagenar macula appears first in the posterior part of the sacculus of elasmobranchs; in these
animals, the lagena is considered to be involved in the balance support (orientation with respect to the gravitation force).
The lagena as a separate endorgan has been described in teleost fishes; in some species, the lagena is connected with the
sacculus, while in other species the interrelations of these structures can be dissimilar. The lagena supplements the functions
of the sacculus; in fishes (animals with no special organ of hearing), it is involved in discrimination of sound oscillations,
identification of the gravitation vector, and orientation in the course of movements within the vertical plane. In amphibians,
the lagena is localized in the posterior part of the sacculus, near the auditory structures; it performs mostly vestibular
and (to a much lesser extent) auditory functions. In amniotes, the lagena was first separated from the sacculus; it is localized
in the cochlear canal, distally with respect to the hearing organ. Information on the functions of the lagena in amniotes
is rather limited and contradictory. Central projections of this organ have been examined practically only in birds. Lagenar
afferents project to the vestibular nuclei and cerebellum, while some fibers come to the auditory nuclei of the medulla. The
lagena in birds can be related to their navigation abilities (birds are supposed to be capable of orienting within the magnetic
field of the Earth due to the magnetic properties of the lagenar otoconia; this structure can also provide detection of movements
along the vertical axis. The close proximity between the otolithic and auditory endorgans in the cochlear canal of amniotes
can be indicative of the functional significance of these interrelations. This aspect, however, remains at present undiscovered.
In mammals (except Monotremata), there is no lagena as an independent endorgan.
Neirofiziologiya/Neurophysiology, Vol. 40, No. 2, pp. 160–178, March–April, 2008. 相似文献
976.
B. K. Shetty 《BMJ (Clinical research ed.)》1994,308(6945):1713-1714
977.
EEG correlates of two main effects of long-term hyperventilation (cyclic breathing similar to rebirthing), namely, psychotic manifestations and sensations in internal organs, are considered. Standard EEGs of 44 subjects were recorded and subsequently treated by multiparametric methods. It was shown that, in the case of psychotic phenomena (hallucinations, visual and auditory images, different scenes, virtual travels, out-of-body experiences, etc.), the changes in the spatial organization of bioelectric potentials as compared with the baseline have different patterns than in the case of sensations in internal organs. The changes are observed in the frontal regions of the cortex: a decrease in spatial synchronization (linear processes) during an increase in spatial disarray (nonlinear processes) of bioelectric potentials and the intensifying of high-frequency β activity. If sensations in internal organs appear, a decrease in the above parameters was observed in the right hemisphere and in posterior cortical areas. The data are discussed from the viewpoint of qualitative specificity of changes in functional states during an altered state of consciousness with manifestations of different psychovisceral phenomena. 相似文献
978.
979.
N Nakagata K Matsumoto M Anzai A Takahashi Y Takahashi Y Matsuzaki K Miyata 《Jikken dobutsu》1992,41(4):537-540
Spermatozoa of a homozygous transgenic mouse, in which the firefly luciferase gene was expressed under the control of beta-actin promoter, were frozen at -196 degrees C. One fourth of the frozen sperm was later thawed and used for in vitro fertilization. Thirty-six of 65 oocytes (55.4%) developed to the 2-cell stage. All the 2-cell embryos were transferred to the oviducts of pseudopregnant recipients and 23 young (63.9%, 23/36) were born. All of young analyzed carried the transgene and showed the luciferase gene expression. 相似文献
980.
Werner E.C. Muller Jürgen Conrad Rudolf K. Zahn Renate Steffen Gerhard Uhlenbruck Isabel Miller 《Differentiation; research in biological diversity》1984,26(1-3):30-35
Abstract. The Hexactinellida sponge Aphrocallistes vastus contains a soluble aggregation factor (AF) whose purification has been described in this communication. It is characterized by a S°20.w value of 37 and a buoyant density of 1.45 g/cm3 . The AF is a glycoporteinaceous particle composed of three major protein species; no core structure could be visualized. In the presence of Ca2+ , the AF causes secondary aggregation of single cells. The aggregation process is temperature, pH, and ionic strength independent within a broad range. Evidence is presented indicating that two (or more) AF molecules are required for the establishment of a stable cell: cell interaction. In contrast to the AFs from demosponges, the hexactinellid AF functions species-unspecifically. 相似文献