The Experts below are selected from a list of 237 Experts worldwide ranked by ideXlab platform
Masahiro Nakano - One of the best experts on this subject based on the ideXlab platform.
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Characteristic difference in gastroIntestinal excretion of clarithromycin and roxithromycin
Biopharmaceutics & drug disposition, 1998Co-Authors: Kazuhiko Arimori, S. Miyamoto, K. Fukuda, C. Nakamura, Masahiro NakanoAbstract:Excretion characteristics of two new macrolides; clarithromycin and roxithromycin, into the Intestinal and the gastric Lumens was studied by in situ single-pass perfusion and loop methods in rats. Roxithromycin maintained higher serum levels than clarithromycin after their intravenous administrations at a dose of 5 mg kg−1 each. Radioactivities of clarithromycin and roxithromycin exsorbed into the Intestinal Lumen were 8.6 and 18.9% of dose in 2 h, respectively, whereas clarithromycin and roxithromycin excreted into the bile were 28.4 and 5.9%, respectively. These results suggest that roxithromycin is transported mainly by exsorption across the Intestinal membrane, whereas clarithromycin mainly by excretion through the biliary tract. On the other hand, radioactivities of clarithromycin and roxithromycin exsorbed into the gastric Lumen were much less then those into the Intestinal Lumen and were 0.72 and 1.34% of dose in 4 h, respectively. Thus, the exsorption into the gastric Lumen seems to be a minor route for the elimination of both macrolides. Consequently, the transport into the Intestinal Lumen via the Intestinal membrane and/or the bile tract may play a significant role in the overall elimination of both macrolides. © 1998 John Wiley & Sons, Ltd.
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Transport of paraquat and mexiletine from the blood into the rat Intestinal Lumen and peritoneal cavity
Journal of Pharmacy and Pharmacology, 1992Co-Authors: Kazuhiko Arimori, Megumi Deshimaru, Emiko Furukawa, Masahiro NakanoAbstract:— Transport of paraquat and mexiletine from the blood into the Intestinal Lumen and the peritoneal cavity was examined after their intravenous administration (paraquat: 20 mg kg−1, mexiletine: 10 mg kg−1) to rats. The average amounts of paraquat transferred into the Intestinal Lumen and the peritoneal cavity were 1·39 and 22·8% of the dose in 120 min, respectively. The average amounts of mexiletine transferred into the Intestinal Lumen and the peritoneal cavity were 6·1 and 2·5% of the dose in 120 min, respectively. The transfer rate of 3H2O into the peritoneal cavity after intravenous administration (1·85 MBq) was greater than that into the Intestinal Lumen. In view of the hydrophilic nature of paraquat cation, a solvent drag effect due to movement of water might contribute to transport of paraquat from the blood to the peritoneal cavity. Differences in transport behaviour across the two membranes could be due to differences in the geometrical factors such as the surface area and the distribution of blood vessels. Differences might also be due to differences in physicochemistry and pharmacological effects of both substances.
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Transport to Intestinal Lumen and Peritoneal Cavity of Intravenously Administered Aprindine in Rats
Chemical & Pharmaceutical Bulletin, 1991Co-Authors: Kazuhiko Arimori, Yoshiko Hashimoto, Masahiro NakanoAbstract:Transfer of aprindine from the blood into the Intestinal Lumen or into the peritoneal cavity was examined after intravenous administration of the drug at a dose of 5 mg/kg in rats. The amount of the drug transferred from the blood into the Intestinal Lumen was much greater than into the peritoneal cavity. The average amounts of aprindine transported into the Intestinal Lumen and the peritoneal cavity were 0.12 and 0.03% of the dose (5 mg/kg) in 120 min, respectively. Thus, a notable difference in the clearance values of the drug was obtained between the Intestinal Lumen (14.8 ml/h) and the peritoneal cavity (4.94 ml/h). The net water flux showed that secretion predominated in the peritoneal transport while absorption overbalanced secretion in the Intestinal transport. It seems likely that a solvent drag effect by water movement did not contribute much to the transport of aprindine from the blood to the Intestinal Lumen or the peritoneal cavity. The differences in transport across the two membranes could be due to differences in the surface area and other geometrical factors. Differences could also be due to a difference in the pharmacologic effects of the drug which causes a decrease in tissue splanchnic perfusion.
Peter H.r. Green - One of the best experts on this subject based on the ideXlab platform.
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use of shape from shading to estimate three dimensional architecture in the small Intestinal Lumen of celiac and control patients
Computer Methods and Programs in Biomedicine, 2013Co-Authors: Edward J. Ciaccio, Christina A. Tennyson, Govind Bhagat, Suzanne K. Lewis, Peter H.r. GreenAbstract:Background: As measured from videocapsule endoscopy images, the small Intestinal mucosa of untreated celiac patients has significantly greater and more varied texture compared to normal patients. Three-dimensional modeling using shape-from-shading principles may further increase classification accuracy. Methods: A sequence of 200 consecutive videocapsule images acquired at a 2s^-^1 frame rate and 576x576 pixel dimension, were obtained at four locations in the small Intestinal Lumen of ten patients with biopsy-proven celiac disease and ten control patients. Each two-dimensional image was converted to a three-dimensional architectural approximation by considering the 256 grayscale level to be linearly representative of image depth. From the resulting three-dimensional architecture, distinct luminal protrusions, representative of the macro-architecture, were automatically identified by computer algorithm. The range and number of protrusions per image, and their width and height, were determined for celiacs versus controls and tabulated as mean+/-SD. Results: The mean number of villous protrusions per image was 402.2+/-15.0 in celiacs versus 420.8+/-24.0 in controls (p<0.001). The average protrusion width was 14.7 pixels in celiacs versus 13.9 pixels in controls (p=0.01). The mean protrusion height was 3.10+/-2.34 grayscale levels for celiacs versus 2.70+/-0.43 grayscale levels for controls (p<0.001). Thus celiac patients had significantly fewer protrusions on the luminal surface of the small intestine as compared with controls, and these protrusions had greater dimensions, suggesting they are indicative of a mosaic (cobblestone) macro-architectural pattern which is common in celiacs. Conclusions: Shape-from-shading modeling is useful to explore luminal macro-architecture and to detect significant differences in luminal morphology in celiac versus normal patients, which can increase the usefulness of videocapsule studies.
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Use of shape-from-shading to estimate three-dimensional architecture in the small Intestinal Lumen of celiac and control patients
Computer methods and programs in biomedicine, 2013Co-Authors: Edward J. Ciaccio, Christina A. Tennyson, Govind Bhagat, Suzanne K. Lewis, Peter H.r. GreenAbstract:Background: As measured from videocapsule endoscopy images, the small Intestinal mucosa of untreated celiac patients has significantly greater and more varied texture compared to normal patients. Three-dimensional modeling using shape-from-shading principles may further increase classification accuracy. Methods: A sequence of 200 consecutive videocapsule images acquired at a 2s^-^1 frame rate and 576x576 pixel dimension, were obtained at four locations in the small Intestinal Lumen of ten patients with biopsy-proven celiac disease and ten control patients. Each two-dimensional image was converted to a three-dimensional architectural approximation by considering the 256 grayscale level to be linearly representative of image depth. From the resulting three-dimensional architecture, distinct luminal protrusions, representative of the macro-architecture, were automatically identified by computer algorithm. The range and number of protrusions per image, and their width and height, were determined for celiacs versus controls and tabulated as mean+/-SD. Results: The mean number of villous protrusions per image was 402.2+/-15.0 in celiacs versus 420.8+/-24.0 in controls (p
Kazuhiko Arimori - One of the best experts on this subject based on the ideXlab platform.
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Characteristic difference in gastroIntestinal excretion of clarithromycin and roxithromycin
Biopharmaceutics & drug disposition, 1998Co-Authors: Kazuhiko Arimori, S. Miyamoto, K. Fukuda, C. Nakamura, Masahiro NakanoAbstract:Excretion characteristics of two new macrolides; clarithromycin and roxithromycin, into the Intestinal and the gastric Lumens was studied by in situ single-pass perfusion and loop methods in rats. Roxithromycin maintained higher serum levels than clarithromycin after their intravenous administrations at a dose of 5 mg kg−1 each. Radioactivities of clarithromycin and roxithromycin exsorbed into the Intestinal Lumen were 8.6 and 18.9% of dose in 2 h, respectively, whereas clarithromycin and roxithromycin excreted into the bile were 28.4 and 5.9%, respectively. These results suggest that roxithromycin is transported mainly by exsorption across the Intestinal membrane, whereas clarithromycin mainly by excretion through the biliary tract. On the other hand, radioactivities of clarithromycin and roxithromycin exsorbed into the gastric Lumen were much less then those into the Intestinal Lumen and were 0.72 and 1.34% of dose in 4 h, respectively. Thus, the exsorption into the gastric Lumen seems to be a minor route for the elimination of both macrolides. Consequently, the transport into the Intestinal Lumen via the Intestinal membrane and/or the bile tract may play a significant role in the overall elimination of both macrolides. © 1998 John Wiley & Sons, Ltd.
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Transport of paraquat and mexiletine from the blood into the rat Intestinal Lumen and peritoneal cavity
Journal of Pharmacy and Pharmacology, 1992Co-Authors: Kazuhiko Arimori, Megumi Deshimaru, Emiko Furukawa, Masahiro NakanoAbstract:— Transport of paraquat and mexiletine from the blood into the Intestinal Lumen and the peritoneal cavity was examined after their intravenous administration (paraquat: 20 mg kg−1, mexiletine: 10 mg kg−1) to rats. The average amounts of paraquat transferred into the Intestinal Lumen and the peritoneal cavity were 1·39 and 22·8% of the dose in 120 min, respectively. The average amounts of mexiletine transferred into the Intestinal Lumen and the peritoneal cavity were 6·1 and 2·5% of the dose in 120 min, respectively. The transfer rate of 3H2O into the peritoneal cavity after intravenous administration (1·85 MBq) was greater than that into the Intestinal Lumen. In view of the hydrophilic nature of paraquat cation, a solvent drag effect due to movement of water might contribute to transport of paraquat from the blood to the peritoneal cavity. Differences in transport behaviour across the two membranes could be due to differences in the geometrical factors such as the surface area and the distribution of blood vessels. Differences might also be due to differences in physicochemistry and pharmacological effects of both substances.
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Transport to Intestinal Lumen and Peritoneal Cavity of Intravenously Administered Aprindine in Rats
Chemical & Pharmaceutical Bulletin, 1991Co-Authors: Kazuhiko Arimori, Yoshiko Hashimoto, Masahiro NakanoAbstract:Transfer of aprindine from the blood into the Intestinal Lumen or into the peritoneal cavity was examined after intravenous administration of the drug at a dose of 5 mg/kg in rats. The amount of the drug transferred from the blood into the Intestinal Lumen was much greater than into the peritoneal cavity. The average amounts of aprindine transported into the Intestinal Lumen and the peritoneal cavity were 0.12 and 0.03% of the dose (5 mg/kg) in 120 min, respectively. Thus, a notable difference in the clearance values of the drug was obtained between the Intestinal Lumen (14.8 ml/h) and the peritoneal cavity (4.94 ml/h). The net water flux showed that secretion predominated in the peritoneal transport while absorption overbalanced secretion in the Intestinal transport. It seems likely that a solvent drag effect by water movement did not contribute much to the transport of aprindine from the blood to the Intestinal Lumen or the peritoneal cavity. The differences in transport across the two membranes could be due to differences in the surface area and other geometrical factors. Differences could also be due to a difference in the pharmacologic effects of the drug which causes a decrease in tissue splanchnic perfusion.
Yuichi Sugiyama - One of the best experts on this subject based on the ideXlab platform.
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role of breast cancer resistance protein bcrp1 abcg2 in the extrusion of glucuronide and sulfate conjugates from enterocytes to Intestinal Lumen
Molecular Pharmacology, 2005Co-Authors: Yasuhisa Adachi, Hiroshi Suzuki, Alfred H. Schinkel, Yuichi SugiyamaAbstract:The purpose of this study is to examine the significance of efflux transporters in the small intestine to extrude glucuronide (G) and sulfate (S) conjugates into the Intestinal Lumen. From this standpoint, we performed in situ Intestinal perfusion experiments by using Eisai hyperbilirubinemic rats (EHBRs) in which the multidrug resistance protein 2 (Mrp2/Abcc2) is hereditarily defective and breast cancer resistance protein (Bcrp1/Abcg2) knockout mice. The Intestinal Lumen of EHBRs and Bcrp1 (-/-) mice was perfused with medium containing 4-methylumbelliferone (4MU) and E3040 [6-hydroxy-5,7-dimethyl-2-methylamino-4-(3-pyridilmethyl) benzothiazole] to determine the efflux of metabolites into the outflow. The efflux of E3040-glucuronide (G) in EHBRs was significantly lower compared with that in normal rats. However, no significant difference was observed for the efflux of 4MU-G, 4MU-sulfate (S), and E3040-S between EHBRs and normal rats. In contrast, the efflux of intracellularly formed 4MU-G, 4MU-S, and E3040-G in Bcrp1 (-/-) mice was significantly lower than that in normal mice. Therefore, Bcrp1 has an important role in extruding glucuronide and sulfate conjugates formed in enterocytes into the Intestinal Lumen, whereas Mrp2 is responsible for the efflux of some glucuronide conjugates.
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Role of breast cancer resistance protein (Bcrp1/Abcg2) in the extrusion of glucuronide and sulfate conjugates from enterocytes to Intestinal Lumen
Molecular pharmacology, 2004Co-Authors: Yasuhisa Adachi, Hiroshi Suzuki, Alfred H. Schinkel, Yuichi SugiyamaAbstract:The purpose of this study is to examine the significance of efflux transporters in the small intestine to extrude glucuronide (G) and sulfate (S) conjugates into the Intestinal Lumen. From this standpoint, we performed in situ Intestinal perfusion experiments by using Eisai hyperbilirubinemic rats (EHBRs) in which the multidrug resistance protein 2 (Mrp2/Abcc2) is hereditarily defective and breast cancer resistance protein (Bcrp1/Abcg2) knockout mice. The Intestinal Lumen of EHBRs and Bcrp1 (-/-) mice was perfused with medium containing 4-methylumbelliferone (4MU) and E3040 [6-hydroxy-5,7-dimethyl-2-methylamino-4-(3-pyridilmethyl) benzothiazole] to determine the efflux of metabolites into the outflow. The efflux of E3040-glucuronide (G) in EHBRs was significantly lower compared with that in normal rats. However, no significant difference was observed for the efflux of 4MU-G, 4MU-sulfate (S), and E3040-S between EHBRs and normal rats. In contrast, the efflux of intracellularly formed 4MU-G, 4MU-S, and E3040-G in Bcrp1 (-/-) mice was significantly lower than that in normal mice. Therefore, Bcrp1 has an important role in extruding glucuronide and sulfate conjugates formed in enterocytes into the Intestinal Lumen, whereas Mrp2 is responsible for the efflux of some glucuronide conjugates.
Edward J. Ciaccio - One of the best experts on this subject based on the ideXlab platform.
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use of shape from shading to estimate three dimensional architecture in the small Intestinal Lumen of celiac and control patients
Computer Methods and Programs in Biomedicine, 2013Co-Authors: Edward J. Ciaccio, Christina A. Tennyson, Govind Bhagat, Suzanne K. Lewis, Peter H.r. GreenAbstract:Background: As measured from videocapsule endoscopy images, the small Intestinal mucosa of untreated celiac patients has significantly greater and more varied texture compared to normal patients. Three-dimensional modeling using shape-from-shading principles may further increase classification accuracy. Methods: A sequence of 200 consecutive videocapsule images acquired at a 2s^-^1 frame rate and 576x576 pixel dimension, were obtained at four locations in the small Intestinal Lumen of ten patients with biopsy-proven celiac disease and ten control patients. Each two-dimensional image was converted to a three-dimensional architectural approximation by considering the 256 grayscale level to be linearly representative of image depth. From the resulting three-dimensional architecture, distinct luminal protrusions, representative of the macro-architecture, were automatically identified by computer algorithm. The range and number of protrusions per image, and their width and height, were determined for celiacs versus controls and tabulated as mean+/-SD. Results: The mean number of villous protrusions per image was 402.2+/-15.0 in celiacs versus 420.8+/-24.0 in controls (p<0.001). The average protrusion width was 14.7 pixels in celiacs versus 13.9 pixels in controls (p=0.01). The mean protrusion height was 3.10+/-2.34 grayscale levels for celiacs versus 2.70+/-0.43 grayscale levels for controls (p<0.001). Thus celiac patients had significantly fewer protrusions on the luminal surface of the small intestine as compared with controls, and these protrusions had greater dimensions, suggesting they are indicative of a mosaic (cobblestone) macro-architectural pattern which is common in celiacs. Conclusions: Shape-from-shading modeling is useful to explore luminal macro-architecture and to detect significant differences in luminal morphology in celiac versus normal patients, which can increase the usefulness of videocapsule studies.
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Use of shape-from-shading to estimate three-dimensional architecture in the small Intestinal Lumen of celiac and control patients
Computer methods and programs in biomedicine, 2013Co-Authors: Edward J. Ciaccio, Christina A. Tennyson, Govind Bhagat, Suzanne K. Lewis, Peter H.r. GreenAbstract:Background: As measured from videocapsule endoscopy images, the small Intestinal mucosa of untreated celiac patients has significantly greater and more varied texture compared to normal patients. Three-dimensional modeling using shape-from-shading principles may further increase classification accuracy. Methods: A sequence of 200 consecutive videocapsule images acquired at a 2s^-^1 frame rate and 576x576 pixel dimension, were obtained at four locations in the small Intestinal Lumen of ten patients with biopsy-proven celiac disease and ten control patients. Each two-dimensional image was converted to a three-dimensional architectural approximation by considering the 256 grayscale level to be linearly representative of image depth. From the resulting three-dimensional architecture, distinct luminal protrusions, representative of the macro-architecture, were automatically identified by computer algorithm. The range and number of protrusions per image, and their width and height, were determined for celiacs versus controls and tabulated as mean+/-SD. Results: The mean number of villous protrusions per image was 402.2+/-15.0 in celiacs versus 420.8+/-24.0 in controls (p
