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Ottar Sjaastad Egilius LH Spierings 《Cephalalgia : an international journal of headache》1984,4(1):65-70
Two cases suffering from a headache apparently at variance with well recognized headaches are described. It is characterized by a steady, non-paroxysmal, probably severe to moderately severe hemicrania localized anteriorly or anteroposteriorly and is not associated with nausea. Indomethacin exerts an absolute, persistent and clearly dose-dependent effect on this headache, which differs from unilateral headache syndromes such as cluster headache and cervicogenic headache in its temporal pattern and indomethacin response. It differs from chronic paroxysmal hemicrania in its temporal pattern and in the lack of accompanying symptoms. 相似文献
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Invasion of erythrocytes by Plasmodium falciparum malaria parasites: evidence for receptor heterogeneity and two receptors 总被引:19,自引:0,他引:19
Plasmodium falciparum malaria parasites with different capabilities of invading sialic acid-deficient erythrocytes were identified. Thai-2 parasites cultured in Tn erythrocytes invaded neuraminidase-treated and Tn erythrocytes twice as efficiently as Thai-2 parasites cultured in normal erythrocytes and seven to ten times more efficiently than a cloned line of Camp parasites cultured in normal erythrocytes. All three parasite lines required sialic acid for optimal invasion, but Thai-2 parasites cultured in Tn erythrocytes invaded neuraminidase- treated erythrocytes with 45% efficiency whereas Camp parasites invaded neuraminidase-treated erythrocytes with less than 10% efficiency. P falciparum malaria parasites probably possess two receptors: one that binds to a sialic acid-dependent ligand and another that binds to a sialic acid-independent ligand. Parasites may differ in the quantity or affinity of their receptors for the sialic acid-independent ligand. 相似文献
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Expression of bcl-xL can confer a multidrug resistance phenotype 总被引:14,自引:3,他引:14
It has been suggested that genes that regulate apoptotic cell death may play an important role in determining the sensitivity of tumor cells to chemotherapy. We have recently cloned a member of the bcl-2 family, bcl- x. To test whether bcl-XL expression affects the sensitivity of tumor cells to chemotherapy, we have created stable cell lines overexpressing bcl-XL and have tested these cells for resistance to cell death induced by metabolic inhibitors and chemotherapeutic agents. Bcl-XL expression dramatically reduces the cytotoxicity of bleomycin, cisplatin, etoposide, vincristine, hygromycin B, and mycophenolic acid for up to 4 days in culture. Bcl-XL does not prevent cells from undergoing cell cycle arrest in response to these drugs, but rather prevents treated cells from undergoing apoptosis. Cell-cycle analysis on cells treated with the chemotherapeutic agents bleomycin, cisplatin, etoposide, and vincristine, show that the drugs cause growth arrest in different positions within the cell cycle. Bcl-XL expressing cells treated with chemotherapeutic drugs retain their proliferative ability after the drugs are removed. Interestingly, vincristine-treated cells expressing bcl-XL become polyploid after drug removal. These data show that bcl-XL protects cells from a wide variety of apoptotic stimuli, acts in multiple positions within the cell cycle, and confers a multidrug resistance phenotype. The ability of bcl-XL to prevent apoptotic cell death in response to chemotherapy-induced DNA damage and cell-cycle arrest may contribute to the accumulation of chromosomal aberrations within tumors. The expression of bcl-XL in tumor cells is likely to be an important indicator of chemotherapeutic efficacy. 相似文献
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