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61.
Cultured mouse L-cells, pulse labeled for 5 min with 3H-uridine, were gently suspended in 0.5mM cupric sulfate and 0.5% sodium dodecyl sulfate at 4 degrees C and treated with cold phenol. Only the RNA, containing less than 1% DNA, was extracted by this procedure. The rapidly labeled ribosomal RNA precursors (44S, 34S) and cytoplasmic 8S RNA showed specific activities higher than that of tRNA and were present in the RNA fraction insoluble in 2M NaCl.  相似文献   
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1-Deoxy-9α-dihydrotaxane analogs 9 and 10 were semi-synthesized from 1-deoxybaccatin VI, isolated from Taxus mairei, and tested for cytotoxic activity. Taxane 9 is 10-fold less cytotoxic than paclitaxel, while 10 is equally active. In the tubulin polymerization assay (ED50 values), 10 is 4-fold less effective than paclitaxel, but 3-fold superior to 9. These observations can be explained by analysis of the corresponding taxane/β-tubulin complexes.  相似文献   
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The first total synthesis of prasinic acid is being reported along with its biological evaluation. The ten step synthesis involved readily available and cheap starting materials and can easily be transposed to large scale manufacturing. The crucial steps of the synthesis included the formation of two different aromatic units (7 and 9) and their coupling reaction. The synthetic prasinic acid exhibited moderate antitumor activity (IC50 4.3–9.1 μM) in different lines of cancer cells.  相似文献   
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Extracellular ATP represents an important autocrine/paracrine signaling molecule within the liver. The mechanisms responsible for ATP release are unknown, and alternative pathways have been proposed, including either conductive ATP movement through channels or exocytosis of ATP-enriched vesicles, although direct evidence from liver cells has been lacking. Utilizing dynamic imaging modalities (confocal and total internal reflection fluorescence microscopy and luminescence detection utilizing a high sensitivity CCD camera) at different scales, including confluent cell populations, single cells, and the intracellular submembrane space, we have demonstrated in a model liver cell line that (i) ATP release is not uniform but reflects point source release by a defined subset of cells; (ii) ATP within cells is localized to discrete zones of high intensity that are ∼1 μm in diameter, suggesting a vesicular localization; (iii) these vesicles originate from a bafilomycin A1-sensitive pool, are depleted by hypotonic exposure, and are not rapidly replenished from recycling of endocytic vesicles; and (iv) exocytosis of vesicles in response to cell volume changes depends upon a complex series of signaling events that requires intact microtubules as well as phosphoinositide 3-kinase and protein kinase C. Collectively, these findings are most consistent with an essential role for exocytosis in regulated release of ATP and initiation of purinergic signaling in liver cells.  相似文献   
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Using a laterality questionnaire, 138 normal healthy individuals were classified as right-sided and 25 as non-right sided. Interleukin-2 (IL-2) was generated from whole blood obtained from these subjects using mitogen (PHA) stimulation. IL-2 was quantitated in picograms/ml using an enzyme immunoassay (ELISA). Additionally, sera from these subjects were tested for 7 autoantibodies by standard serological methods. As compared to right sided subjects, non-right sided individuals had significantly lower IL-2 production. Non-right sided individuals with autoantibodies had significantly lower IL-2 production than right sided subjects with or without autoantibodies, but did not differ significantly from their non-right sided counterparts without autoantibodies. These data support the increasing evidence for the differential and lateralized regulation of immune functions by the right and left cerebral regions.  相似文献   
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The objective of this investigation was to evaluate the effect of delivery strategies such as cyclodextrin complexation and liposomes on the topical delivery of ketorolac acid (KTRA) and ketorolac tromethamine. Ketorolac acid–hydroxypropyl-β-cyclodextrin solid dispersions (KTRA-CD) were prepared by kneading method. The liposomes containing ketorolac tromethamine (KTRM) and KTRA-CD were prepared. The in vitro permeation of KTRM solution, KTRA solution, KTRA-CD, and liposomes containing KTRM or KTRA-CD through guinea pig skin was evaluated. The anti-inflammatory activity of the topically applied KTRA-CD gel (containing 1% w/w KTRA) was compared to that of orally delivered KTRM solution. The KTRA-CD demonstrated significantly higher transdermal transport of ketorolac as compared to all other systems whereas liposomes significantly reduced the transport of ketorolac. The anti-inflammatory activity of the topically applied KTRA-CD gel was similar to that of the orally administered KTRM. Thus, cyclodextrin complexation enabled effective transdermal delivery of the ketorolac.  相似文献   
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