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Unexpected thymic hyperplasia in transgenic mice harboring a neuronal promoter fused with simian virus 40 large T antigen. 总被引:13,自引:3,他引:10
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F M Botteri H van der Putten D F Wong C A Sauvage R M Evans 《Molecular and cellular biology》1987,7(9):3178-3184
The hypothalamic peptide growth hormone-releasing factor (GRF) regulates the secretion and production of growth hormone from the anterior pituitary (M. C. Gelato and G. R. Merriam, Annu. Rev. Physiol. 48:569-591). To study GRF gene regulation, transgenic mice were generated that harbor the human GRF promoter fused to the coding sequences from the simian virus 40 early region. These mice had normal hypothalamic functions but unexpectedly suffered from severe thymic hyperplasia. Immunohistochemical analysis revealed that large T antigen was expressed in the thymic epithelial cells. These cells have endocrine properties and are known to produce thymic hormones [corrected]. The thymic hyperplasia was the apparent consequence of inappropriate production of T-cell maturation factors by epithelial cells and could involve increased self renewal of apparently normal T stem cells in the thymus. 相似文献
95.
Dr. Brian H. Peters 《Cell and tissue research》1987,249(2):341-350
Summary An electron-microscopical study of locust thoracic ganglia reveals that synapses in the neuropily are morphologically heterogeneous. In addition to the conventional dyadic type described frequently in the literature, there is a second type with a complex arrangement of presynaptic dense material and a non-dyadic postsynaptic configuration. Serial-section analysis of these synapses suggests that the presynaptic structures include irregular or curved bars, and small projections.Although the proportion of non-dyadic synapses in the neuropile as a whole is small, a substantial number have been found on the branches of an identified flight motor neurone, labelled intracellularly with metal ions in conjunction with silver intensification. Samples from the arborization of this neurone give some indications of the distribution of non-dyadic synapses on it.The results are discussed in the context of distribution of synapses on other identified locust neurones, and the functional morphology of synapses in other phyla. 相似文献
96.
Mass spectrometric determinations of O2 affinities by the rumen fungus Neocallimastix patriciarum indicated a stable respiration under liquid phase O2 concentrations up to 10 M, the apparent K
m for O2 under these conditions was 4.0 M. Exposure to O2 concentrations in excess of 10 M resulted in rapid inactivation of the observed respiration. Calculated H2 evolution rates for the organism are 8.1 nmol min-1 per mg of protein. Exposure to liquid-phase O2 concentrations in excess of 1.4 M caused 50% inhibition of H2 production. That superoxide and peroxide are amongst the products of respiration was shown by the use of ESR spectroscopy with the spin trapping agent 5,5-dimethyl-l-pyrroline-N-oxide. An active superoxide dismutase was present, but catalase could not be detected.Abbreviations ESR
electron spin resonance
- DMPO
5,5-dimethyl-l-pyrroline-N-oxide
- DETAPAC
diethylene-triamine pentaacetic acid 相似文献
97.
GABA-mediated synaptic inhibition of projection neurons in the antennal lobes of the sphinx moth,Manduca sexta 总被引:3,自引:0,他引:3
Brian Waldrop Thomas A. Christensen John G. Hildebrand 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1987,161(1):23-32
Responses of neurons in the antennal lobe (AL) of the moth Manduca sexta to stimulation of the ipsilateral antenna by odors consist of excitatory and inhibitory synaptic potentials. Stimulation of primary afferent fibers by electrical shock of the antennal nerve causes a characteristic IPSP-EPSP synaptic response in AL projection neurons. The IPSP in projection neurons reverses below the resting potential, is sensitive to changes in external and internal chloride concentration, and thus is apparently mediated by an increase in chloride conductance. The IPSP is reversibly blocked by 100 microM picrotoxin or bicuculline. Many AL neurons respond to application of GABA with a strong hyperpolarization and an inhibition of spontaneous spiking activity. GABA responses are associated with an increase in neuronal input conductance and a reversal potential below the resting potential. Application of GABA blocks inhibitory synaptic inputs and reduces or blocks excitatory inputs. EPSPs can be protected from depression by application of GABA. Muscimol, a GABA analog that mimics GABA responses at GABAA receptors but not at GABAB receptors in the vertebrate CNS, inhibits many AL neurons in the moth. 相似文献
98.
G Evans 《BMJ (Clinical research ed.)》1987,294(6587):1569-1570
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S P O'Hickey C A Pickering P E Jones J D Evans 《BMJ (Clinical research ed.)》1987,294(6588):1663-1667
On 22 August 1985 a fire occurred on a Boeing 737 jet airliner at take off at Manchester Airport. One hundred and thirty seven passengers and crew were on board. Fifty two passengers died on the aircraft, 85 escaped. Most survivors had minor physical injuries, but 15 required admission to hospital because of smoke inhalation and two of these had severe burns. At presentation only one survivor required ventilation but within 12 hours a further five required ventilation. Although initially patients suffering from smoke inhalation may seem relatively well, lung function may deteriorate rapidly in the first 24 hours. Careful organisation and regular practice of procedures to deal with a major accident are essential to be able to respond adequately to such an event. 相似文献