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971.
972.
Chronic expression of P-selectin on endothelial cells stimulated by the T-cell cytokine, interleukin-3 总被引:10,自引:0,他引:10
Khew-Goodall Y; Butcher CM; Litwin MS; Newlands S; Korpelainen EI; Noack LM; Berndt MC; Lopez AF; Gamble JR; Vadas MA 《Blood》1996,87(4):1432-1438
P-selectin expressed on the surface of endothelium mediates leukocyte adhesion in vitro and rolling in vivo. Several inducers of cell-surface P-selectin expression on endothelial cells (EC) have previously been identified, all of which yield transient cell-surface expression of P- selectin lasting minutes to a few hours. We now show that a T- lymphocyte product, interleukin-3 (IL-3), stimulates the long-term endothelial cells (HUVEC). IL-3 induced cell-surface P-selectin expression in two phases. An initial peak at 10 minutes was followed by a prolonged upregulation beginning 16 hours after IL-3 addition and lasting at least 4 days. The level of P-selectin expression induced by IL-3 added for 48 hours was similar to that induced by treatment of HUVEC for 10 minutes with thrombin, and the effect of adding IL-3 for 48 hours followed by thrombin for 10 minutes was additive. Induction of cell-surface P-selectin expression by IL-3 was blocked by pretreatment of EC with a blocking monoclonal antibody against the IL-3 receptor alpha-chain. Lipopolysaccharide (LPS), tumor necrosis factor alpha (TNF alpha) and a mutant form of IL-3 with decreased potency did not induce cell-surface P-selectin expression after 48 hours' incubation with HUVEC, suggesting that the effect was specific to IL-3. The increase in cell-surface P-selectin expression occurring after 16 hours of incubation with IL-3 was accompanied by a similar prolonged increase in the steady-state mRNA level that was not observed at 10 minutes after IL-3 addition. As T-lymphocyte infiltration is a hallmark of chronic inflammation, our observations suggest that the secretion of IL-3 by T lymphocytes may serve to maintain the inflammatory state during chronic inflammation. 相似文献
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The cutaneous form of polyarteritis nodosa in children is extremely rare. Findings are usually limited to the skin, muscles and joints. It has a benign but often chronic course. We describe an 8-y-old girl with cutaneous PAN, with extensive livedo reticularis on lower and upper extremities, tender subcutaneous nodules, arthralgia and right ankle swelling. Skin biopsy revealed vasculitis of small and medium-sized blood vessels characterized by fibrinoid necrosis. The use of prednisolone resulted in clinical improvement initially, but recurrence occurred during tapering. She showed marked improvement with additional high dose methyl prednisolone monthly. 相似文献
975.
View-invariant representations of familiar objects by neurons in the inferior temporal visual cortex 总被引:10,自引:4,他引:6
A view-invariant representation of objects in the brain would have many
computational advantages. Here we describe a population of single neurons
in the temporal visual cortex (IT) that have view-invariant representations
of familiar objects. Ten real plastic objects were placed in the monkeys'
home cages for a period of time before neurophysiological experiments in
which neuronal responses were measured to four views of each object. The
macaques performed a visual fixation task, and had never been trained in
object discrimination. The majority of the visual neurons recorded were
responsive to some views of some objects and/or to the control stimuli, as
would be expected from previous studies. However, a small subset of these
neurons were responsive to all views of one or more of the objects,
providing evidence that these neurons were coding for objects, rather than
simply for individual views or visual features within the image. This
result was confirmed by information theoretic analyses, which showed that
the neurons provided information about which object was being seen,
independently of the view. The coding scheme was shown to be sparse
distributed, with relatively independent information being provided by the
different neurons. Hypotheses about how these view-invariant cells are
formed are described.
相似文献
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