The Experts below are selected from a list of 213 Experts worldwide ranked by ideXlab platform
Hiroshi Iwase - One of the best experts on this subject based on the ideXlab platform.
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determination of Cyanocobalamin in foods by high performance liquid chromatography with visible detection after solid phase extraction and membrane filtration for the precolumn separation of lipophilic species
Journal of Chromatography A, 1997Co-Authors: Hiroshi Iwase, Ichiro OnoAbstract:Determination of trace amounts of Cyanocobalamin (18 ng/g) in fatty foods was performed by solid-phase extraction and high-performance liquid chromatography (HPLC) with visible detection at 550 nm using a membrane filter for the precolumn separation of particulate material. It was found that a membrane filter (HLC-Disk 25, 0.45 μm) was most suitable for the separation of oily particulates. A sample solution was applied to a solid-phase extraction cartridge and then Cyanocobalamin was eluted using a 50% aqueous acetonitrile solution followed by HPLC. This method was suitable for the determination of trace amounts of Cyanocobalamin in nutrient samples. The proposed method was simple, rapid (extraction time: ca. 12 min, analysis time: ca. 12 min), sensitive (detection limit: ca. 0.15 ng at a signal-to-noise ratio of 3:1), highly selective and reproducible (relative standard deviation: 2.67%) for Cyanocobalamin. The calibration graph for Cyanocobalamin was linear in the range of 0.1 to 30 ng. Recovery of Cyanocobalamin was over 90% by the standard addition method.
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ultramicrodetermination of Cyanocobalamin in elemental diet by solid phase extraction and high performance liquid chromatography with visible detection
Journal of Chromatography A, 1992Co-Authors: Hiroshi IwaseAbstract:Abstract The ultramicrodetermination of Cyanocobalamin (9 ng/g) in elemental diet containing 46 kinds of compounds, with concentrations at least 50–10 6 times higher than that of Cyanocobalamin, was performed by Sep-Pak C 18 purification and concentration of Cyanocobalamin followed by HPLC with detection at 550 nm. The method is simple, rapid, sensitive and reproducible. The calibration graph was linear in the range of 0-0.2 μg. The recovery of Cyanocobalamin was over 95% by the standard addition method. There was good agreement between the Cyanocobalamin concentrations indicated and found.
Ichiro Ono - One of the best experts on this subject based on the ideXlab platform.
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determination of Cyanocobalamin in foods by high performance liquid chromatography with visible detection after solid phase extraction and membrane filtration for the precolumn separation of lipophilic species
Journal of Chromatography A, 1997Co-Authors: Hiroshi Iwase, Ichiro OnoAbstract:Determination of trace amounts of Cyanocobalamin (18 ng/g) in fatty foods was performed by solid-phase extraction and high-performance liquid chromatography (HPLC) with visible detection at 550 nm using a membrane filter for the precolumn separation of particulate material. It was found that a membrane filter (HLC-Disk 25, 0.45 μm) was most suitable for the separation of oily particulates. A sample solution was applied to a solid-phase extraction cartridge and then Cyanocobalamin was eluted using a 50% aqueous acetonitrile solution followed by HPLC. This method was suitable for the determination of trace amounts of Cyanocobalamin in nutrient samples. The proposed method was simple, rapid (extraction time: ca. 12 min, analysis time: ca. 12 min), sensitive (detection limit: ca. 0.15 ng at a signal-to-noise ratio of 3:1), highly selective and reproducible (relative standard deviation: 2.67%) for Cyanocobalamin. The calibration graph for Cyanocobalamin was linear in the range of 0.1 to 30 ng. Recovery of Cyanocobalamin was over 90% by the standard addition method.
Ken-ichi Hosoya - One of the best experts on this subject based on the ideXlab platform.
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Investigation of Receptor-Mediated Cyanocobalamin (Vitamin B12) Transport across the Inner Blood-Retinal Barrier Using Fluorescence-Labeled Cyanocobalamin.
Molecular pharmaceutics, 2018Co-Authors: Yuri Kinoshita, Kagayaki Nogami, Ryuta Jomura, Shin-ichi Akanuma, Hajime Abe, Masahiko Inouye, Yoshiyuki Kubo, Ken-ichi HosoyaAbstract:The blood-to-retina supply of Cyanocobalamin (vitamin B12) across the blood–retinal barrier (BRB) was investigated by synthesizing a fluorescence-labeled Cyanocobalamin (Cy5-Cyanocobalamin). In the in vivo analysis following internal jugular injection of Cy5-Cyanocobalamin, confocal microscopy showed the distribution of Cy5-Cyanocobalamin in the inner plexiform layer (IPL), the outer plexiform layer (OPL), and the retinal pigment epithelium (RPE). In the in vitro analysis with TR-iBRB2 cells, an in vitro model cell line of the inner BRB, Cy5-Cyanocobalamin uptake by TR-iBRB2 cells exhibited a time-dependent increase after preincubation with transcobalamin II (TCII) protein, during its residual uptake without preincubation with TCII protein. The Cy5-Cyanocobalamin uptake by TR-iBRB2 cells was significantly reduced in the presence of unlabeled Cyanocobalamin, chlorpromazine, and chloroquine and was also significantly reduced under Ca2+-free conditions. Confocal microscopy of the TR-iBRB2 cells showed fluore...
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Investigation of Receptor-Mediated Cyanocobalamin (Vitamin B12) Transport across the Inner Blood–Retinal Barrier Using Fluorescence-Labeled Cyanocobalamin
2018Co-Authors: Yuri Kinoshita, Kagayaki Nogami, Ryuta Jomura, Shin-ichi Akanuma, Hajime Abe, Masahiko Inouye, Yoshiyuki Kubo, Ken-ichi HosoyaAbstract:The blood-to-retina supply of Cyanocobalamin (vitamin B12) across the blood–retinal barrier (BRB) was investigated by synthesizing a fluorescence-labeled Cyanocobalamin (Cy5-Cyanocobalamin). In the in vivo analysis following internal jugular injection of Cy5-Cyanocobalamin, confocal microscopy showed the distribution of Cy5-Cyanocobalamin in the inner plexiform layer (IPL), the outer plexiform layer (OPL), and the retinal pigment epithelium (RPE). In the in vitro analysis with TR-iBRB2 cells, an in vitro model cell line of the inner BRB, Cy5-Cyanocobalamin uptake by TR-iBRB2 cells exhibited a time-dependent increase after preincubation with transcobalamin II (TCII) protein, during its residual uptake without preincubation with TCII protein. The Cy5-Cyanocobalamin uptake by TR-iBRB2 cells was significantly reduced in the presence of unlabeled Cyanocobalamin, chlorpromazine, and chloroquine and was also significantly reduced under Ca2+-free conditions. Confocal microscopy of the TR-iBRB2 cells showed fluorescence signals of Cy5-Cyanocobalamin and GFP-TCII protein, and these signals merged with each other. The RT-PCR, Western blot, and immunohistochemistry clearly suggested the expression of TCII receptor (TCII-R) in the inner and outer BRB. These results suggested the involvement of receptor-mediated endocytosis in the blood-to-retina transport of Cyanocobalamin at the inner BRB with implying its possible involvement at the outer BRB
Ebba Nexo - One of the best experts on this subject based on the ideXlab platform.
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Increase in circulating holotranscobalamin after oral administration of Cyanocobalamin or hydroxocobalamin in healthy adults with low and normal cobalamin status
European Journal of Nutrition, 2018Co-Authors: Eva Greibe, Namita Mahalle, Vijayshri Bhide, Christian W. Heegaard, Sadanand Naik, Ebba NexoAbstract:Purpose To investigate the absorption of synthetic Cyanocobalamin and natural occurring hydroxocobalamin in populations with low and normal cobalamin (vitamin B12) status. Methods We included adults with low ( n = 59) and normal ( n = 42) cobalamin status and measured the change in serum holotranscobalamin (ΔholoTC) before and after 2 day administration of different doses of Cyanocobalamin and hydroxocobalamin (CobaSorb test). In the low status group, the test was performed using a cross-over design with identical doses of both cobalamin forms (1.5, 3, and 6 µg, respectively). In the normal status group, the test was performed with either 3, 6, and 9 µg Cyanocobalamin ( n = 28), or with 9 µg Cyanocobalamin and 9 µg hydroxocobalamin ( n = 14). Results In both groups, median ΔholoTC (pmol/L) was higher after intake of Cyanocobalamin compared to (hydroxocobalamin) [low status: 1.5 µg: 19 (6); 3 µg: 23 (7); 6 µg: 30 (14); normal status: 9 µg: 30 (13) pmol/L]. Independent of B12 form, no difference was observed in ΔholoTC between those receiving 1.5 and 3 µg in the low status group or 6 and 9 µg Cyanocobalamin in the normal status group. However, in both groups, administration of 6 µg cobalamin resulted in a significant higher ΔholoTC than did 3 µg [low status: p = 0.02 (0.009) for Cyanocobalamin (hydroxocobalamin); normal status: p = 0.03 for Cyanocobalamin]. Conclusions Administration of Cyanocobalamin resulted in a more than twofold increase in holoTC in comparison with hydroxocobalamin. The absorptive capacity was reached only by doses above 3 µg cobalamin. Our results underscore the importance of using the same form of cobalamin when comparing uptake under different conditions. Clinical trial registry number NCT02832726 at https://clinicaltrials.gov and 2016/09/012147 at Clinical Trials Registry India.
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Increase in circulating holotranscobalamin after oral administration of Cyanocobalamin or hydroxocobalamin in healthy adults with low and normal cobalamin status.
European journal of nutrition, 2017Co-Authors: Eva Greibe, Namita Mahalle, Vijayshri Bhide, Christian W. Heegaard, Sadanand S Naik, Ebba NexoAbstract:To investigate the absorption of synthetic Cyanocobalamin and natural occurring hydroxocobalamin in populations with low and normal cobalamin (vitamin B12) status. We included adults with low (n = 59) and normal (n = 42) cobalamin status and measured the change in serum holotranscobalamin (ΔholoTC) before and after 2 day administration of different doses of Cyanocobalamin and hydroxocobalamin (CobaSorb test). In the low status group, the test was performed using a cross-over design with identical doses of both cobalamin forms (1.5, 3, and 6 µg, respectively). In the normal status group, the test was performed with either 3, 6, and 9 µg Cyanocobalamin (n = 28), or with 9 µg Cyanocobalamin and 9 µg hydroxocobalamin (n = 14). In both groups, median ΔholoTC (pmol/L) was higher after intake of Cyanocobalamin compared to (hydroxocobalamin) [low status: 1.5 µg: 19 (6); 3 µg: 23 (7); 6 µg: 30 (14); normal status: 9 µg: 30 (13) pmol/L]. Independent of B12 form, no difference was observed in ΔholoTC between those receiving 1.5 and 3 µg in the low status group or 6 and 9 µg Cyanocobalamin in the normal status group. However, in both groups, administration of 6 µg cobalamin resulted in a significant higher ΔholoTC than did 3 µg [low status: p = 0.02 (0.009) for Cyanocobalamin (hydroxocobalamin); normal status: p = 0.03 for Cyanocobalamin]. Administration of Cyanocobalamin resulted in a more than twofold increase in holoTC in comparison with hydroxocobalamin. The absorptive capacity was reached only by doses above 3 µg cobalamin. Our results underscore the importance of using the same form of cobalamin when comparing uptake under different conditions. NCT02832726 at https://clinicaltrials.gov and 2016/09/012147 at Clinical Trials Registry India.
Emmanuel Shapira - One of the best experts on this subject based on the ideXlab platform.
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Biochemical and clinical response to hydroxocobalamin versus Cyanocobalamin treatment in patients with methylmalonic acidemia and homocystinuria (cblC)
The Journal of pediatrics, 1998Co-Authors: Hans C. Andersson, Emmanuel ShapiraAbstract:Abstract Objective: To compare the therapeutic effectiveness of hydroxocobalamin and Cyanocobalamin in patients with combined methylmalonic acidemia and homocystinuria. Study design: Analysis of urine methylmalonic acid, plasma homocystine, and growth of two unrelated patients with cobalamin C disease who were initially receiving Cyanocobalamin and were subsequently switched to hydroxocobalamin. Results: Each patient had a significant decrease in urine methylmalonic acid excretion while receiving Cyanocobalamin, but levels remained at least 10 times normal. Cyanocobalamin treatment resulted in a decrease of plasma homocystine to near normal in one patient but had no effect on plasma homocystine in the second patient. Each patient was switched to hydroxocobalamin and urine methylmalonic acid levels decreased to the limit of detection. Plasma homocystine values while taking hydroxocobalamin remained Conclusion: Intramuscular Cyanocobalamin treatment is inadequate in the treatment of patients with cobalamin C disease. Appropriate management of cobalamin C disease should include only the hydroxocobalamin form of cobalamin. (J Pediatr 1998;132:121-4)
