The Experts below are selected from a list of 51 Experts worldwide ranked by ideXlab platform
Nobuyuki Nakajima - One of the best experts on this subject based on the ideXlab platform.
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Haptotactic migration of pancreatic cancer cells induced by bioactive components in bovine Liver Extract.
Journal of surgical oncology, 1998Co-Authors: Hiroshi Ito, Masaru Miyazaki, Fusanori Nishimura, Nobuyuki NakajimaAbstract:Background and Objectives: Migration into subendothelial tissue in remote organ by cancer cells are crucial events for organ-specific metastasis, including Liver metastasis. This study aims to investigate the chemoattractive ingredients in Liver Extract, which induce migration of Liver metastatic cancer cells. Methods Cell migrations of SU.86.86 cells, human pancreatic cancer cells raised from Liver metastasis, toward the bovine Liver Extract were studied by chemotaxis or haptotaxis assay. Bovine Liver Extract was partially purified by chromatographic or gel elutriation method. Results The soluble fraction of the Liver Extract did not induce chemotactic migration of SU.86.86 cells. However, the insoluble fraction induced a remarkable haptotactic migratory response. C18 column unbound insoluble fractions eluted from SDS-PAGE induced chemotactic migration of SU.86.86 cells. Conclusion Such bioactive components in Liver Extract may play an important role in the development of Liver metastasis. J. Surg. Oncol. 1998;68:153–158. © 1998 Wiley-Liss, Inc.
Alan Anderson - One of the best experts on this subject based on the ideXlab platform.
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the detection of promutagen activation by Extracts of cells expressing cytochrome p450ia2 cdna preincubation dramatically increases revertant yield in the ames test
Mutation Research Letters, 1992Co-Authors: Yvon Trottier, William I Waithe, Alan AndersonAbstract:Abstract Two slightly different protocols, the plate incorporation method and the preincubation method, are used in the Ames Salmonella mutagen test. Using a preincubation method, we recently demonstrated efficient activation of a number of food-derived promutagens by Extracts of mammalian cells expressing cDNAs of rat-Liver cytochrome P450IA2 and of a P450IA2-IA1 hybrid. We report here that, for 2-amino-3,4-dimethylimidazo[4,5-ƒ]quinoline (MeIQ), 1-aminoanthracene and several other promutagens, preincubation dramatically increased the number of revertant colonies in the Ames test when Extracts of cytochrome P450IA2-containing transfected cells or low concentrations of rat-Liver Extracts were used as the source of activating enzymes. At higher concentrations of rat-Liver Extract protein, the effect of preincubation was less pronounced. The effect of preincubation was not due to the low protein concentrations in the assays since increasing the total protein concentration did not abolish the requirement for preincubation for the detection of MeIQ activation at low concentrations of rat-Liver Extract. In experiments where P450IA2 synthesized in transfected cells in culture is used to study promutagen activation, the plate incorporation protocol may seriously underestimate the capacity of cell Extracts to activate promutagens. Thus, interlaboratory comparisons become difficult and unnecessarily large quantities of cell Extract protein may be needed to detect promutagen activation. Whenever Ames test assays are carried out under conditions where P450 concentration limits revertant yield, it would be prudent to examine both the preincubation and plate incorporation protocol.
Kiyohisa Mizumoto - One of the best experts on this subject based on the ideXlab platform.
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Positive and negative host factors for Sendai virus transcription and their organ distribution in rat
Archives of Virology, 1996Co-Authors: Toshimitsu Takagi, Katsuo Seta, Toshihiko Tsukamoto, Minako Iwama, T Kanda, S. Tominaga, Kiyohisa MizumotoAbstract:In vitro mRNA synthesis by Sendai virus is almost entirely dependent on the addition of cellular proteins (positive host factors), one of which could be tubulin. In this study, we investigated the distribution of host factors in various rat organs. Extracts from the brain, thymus, heart, lung, testis, ovary, and uterus all supported in vitro Sendai virus transcription, among which the highest activity was obtained with the brain Extract. On the other hand, little or no activity was detected in the Liver, spleen, and kidney Extracts. An inverse correlation between the apparent host factor activity to stimulate mRNA synthesis and RNase activity that hydrolyzes Sendai virus mRNAs was found, except in the Liver Extract. However, when a transcription initiation complex was isolated and subjected to RNA chain elongation reaction, all of the Extracts including those from Liver, spleen and kidney, were active. Immunoblotting showed that tubulin molecules were integrated in these initiation complexes, supporting the notion that tubulin is involved in the initiation complex formation. We also identified a transcription inhibitory activity without any detectable RNase activity in the Liver Extract. This negative host factor seemed to act on RNA chain elongation. It is likely that Sendai virus transcription is regulated by both positive and negative regulatory factors.
Hiroshi Ito - One of the best experts on this subject based on the ideXlab platform.
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Haptotactic migration of pancreatic cancer cells induced by bioactive components in bovine Liver Extract.
Journal of surgical oncology, 1998Co-Authors: Hiroshi Ito, Masaru Miyazaki, Fusanori Nishimura, Nobuyuki NakajimaAbstract:Background and Objectives: Migration into subendothelial tissue in remote organ by cancer cells are crucial events for organ-specific metastasis, including Liver metastasis. This study aims to investigate the chemoattractive ingredients in Liver Extract, which induce migration of Liver metastatic cancer cells. Methods Cell migrations of SU.86.86 cells, human pancreatic cancer cells raised from Liver metastasis, toward the bovine Liver Extract were studied by chemotaxis or haptotaxis assay. Bovine Liver Extract was partially purified by chromatographic or gel elutriation method. Results The soluble fraction of the Liver Extract did not induce chemotactic migration of SU.86.86 cells. However, the insoluble fraction induced a remarkable haptotactic migratory response. C18 column unbound insoluble fractions eluted from SDS-PAGE induced chemotactic migration of SU.86.86 cells. Conclusion Such bioactive components in Liver Extract may play an important role in the development of Liver metastasis. J. Surg. Oncol. 1998;68:153–158. © 1998 Wiley-Liss, Inc.
Yvon Trottier - One of the best experts on this subject based on the ideXlab platform.
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the detection of promutagen activation by Extracts of cells expressing cytochrome p450ia2 cdna preincubation dramatically increases revertant yield in the ames test
Mutation Research Letters, 1992Co-Authors: Yvon Trottier, William I Waithe, Alan AndersonAbstract:Abstract Two slightly different protocols, the plate incorporation method and the preincubation method, are used in the Ames Salmonella mutagen test. Using a preincubation method, we recently demonstrated efficient activation of a number of food-derived promutagens by Extracts of mammalian cells expressing cDNAs of rat-Liver cytochrome P450IA2 and of a P450IA2-IA1 hybrid. We report here that, for 2-amino-3,4-dimethylimidazo[4,5-ƒ]quinoline (MeIQ), 1-aminoanthracene and several other promutagens, preincubation dramatically increased the number of revertant colonies in the Ames test when Extracts of cytochrome P450IA2-containing transfected cells or low concentrations of rat-Liver Extracts were used as the source of activating enzymes. At higher concentrations of rat-Liver Extract protein, the effect of preincubation was less pronounced. The effect of preincubation was not due to the low protein concentrations in the assays since increasing the total protein concentration did not abolish the requirement for preincubation for the detection of MeIQ activation at low concentrations of rat-Liver Extract. In experiments where P450IA2 synthesized in transfected cells in culture is used to study promutagen activation, the plate incorporation protocol may seriously underestimate the capacity of cell Extracts to activate promutagens. Thus, interlaboratory comparisons become difficult and unnecessarily large quantities of cell Extract protein may be needed to detect promutagen activation. Whenever Ames test assays are carried out under conditions where P450 concentration limits revertant yield, it would be prudent to examine both the preincubation and plate incorporation protocol.