Biomedical subjects

Yoichiro Ito

Publications and source records attributed to Yoichiro Ito.

50 records · Page 3Linked to original sources

PubMed2003

Novel method for continuous cell separation by density gradient centrifugation: evaluation of a miniature separation column.

A compact bench-top model of the centrifuge enables continuous cell separation based on density differences. The apparatus holds a small separation disk equipped with a circular channel (8 mL capacity) separated by a septum. A set of isotonic Percoll media with different densities is continuously introduced at one terminal and collected from the other. Under a centrifugal force field, cell suspension introduced into the proximal portion of the channel results in continuous separation of cells according to their densities. The performance of the apparatus was demonstrated with the separation of human buffy coat containing nucleated cells (>10(8)) among a large population (10(10)) of RBC. The results indicated that the method is capable of separating a large number of nucleated cells, with minimum damage, for a few hours of operation wherein neutrophils are well resolved from lymphocytes. The method may be applied to other types of samples including cord blood, blood from small animals, cultured cells, pancreatic beta cell islets, malaria parasites, sperm cells, etc.

Blood Cell Count↗

PubMed2002

Purification of long-chain fatty acid ester of epigallocatechin-3-O-gallate by high-speed counter-current chromatography.

Epigallocatechin-3-O-gallate (EGCG) was modified by catalytic esterification with hexadecanoyl chloride. A long-chain fatty acid ester derivative was obtained from the purification of this reaction product by high-speedcounter-current chromatography using a solvent system composed of n-hexane-ethyl acetate-methanol-water (1:1:1:1, v/v). The structure of the derivative, epigallocatechin-3-O-gallate-4'-hexadecanate, was elucidated by IR, MS and 1H NMR.

Catechin↗

PubMed2002

Purification of (+)-dihydromyricetin from leaves extract of Ampelopsis grossedentata using high-speed countercurrent chromatograph with scale-up triple columns.

Purification of (+)-dihydromyricetin from an extract (16 g) of leaves of Ampelopsis grossedentata was performed using a preparative triple-column countercurrent chromatograph. With a solvent system composed of n-hexane-ethyl acetate-methanol-water (1:3:2:4, v/v) 11.3 g of (+)-dihydromyricetin was obtained at a high purity of over 99% by HPLC at 254 nm in 9 h.

Ampelopsis↗

PubMed2002

Separation of salidroside from Rhodiola crenulata by high-speed counter-current chromatography.

High-speed counter-current chromatography (HSCCC) was used to purify salidroside from an extract of Rhodiola crenulata with two steps using a two-phase solvent system composed of ethyl acetate-n-butanol-water (1:4:5, v/v) in the first run and chloroform-methanol-isopropanol-water (5:6:1:4) in the second run. The method yielded 21.9 mg of salidroside from 1.216 g of the crude sample at 98% purity determined by HPLC analyses. Identification was performed by 1H NMR, 13C NMR, and MS.

Countercurrent Distribution↗

PubMed2002

Purification of lactic acid dehydrogenase from crude bovine heart extract by pH-peak focusing counter-current chromatography.

pH-peak focusing counter-current chromatography (CCC) was applied to the purification of lactic acid dehydrogenase (LDH) from a crude bovine heart extract using a cross-axis coil planet centrifuge (CPC). The experiment was performed with two sets of polymer phase systems composed of 16% (w/w) polyethylene glycol (PEG) 1000-12.5% (w/w) potassium phosphate buffer and 15% (w/w) PEG 1540-15% (w/w) ammonium sulfate each at various pH values. The best result was achieved from the PEG 1540-ammonium sulfate polymer phase system by adding a retainer (10 mM acetic acid) to the upper stationary phase and an eluter (100 mM sodium hydroxide) to the lower mobile phase. At a flow-rate of 0.5 ml/min, LDH was eluted as a sharp peak which was well resolved from other proteins. Collected fractions were analyzed by the LDH enzymatic activity and by sodium dodecyl sulfate-polyacrylamide slab gel electrophoresis to detect contaminated proteins. LDH was purified directly from crude bovine heart extract in a concentrated state.

Animals↗

PubMed2002

Preparative separation of isomeric sulfophthalic acids by conventional and pH-zone-refining counter-current chromatography.

Two modes of high-speed counter-current chromatography (HSCCC) were applied to separate 3- and 4-sulfophthalic acid from a mixture. Conventional HSCCC was useful for the separation of up to several hundred milligram quantities of these positional isomers, while pH-zone-refining CCC was implemented successfully to separations at the multigram level. The conventional HSCCC separations were performed with a standard J-type HSCCC system that has a superior resolution but a lower level of retention of the stationary phase of the biphasic solvent system used (acidified n-butanol-water). The pH-zone-refining CCC separations were performed with an X-type HSCCC system (a cross-axis system) that has a higher capability for retention of the stationary phase. The purified positional isomers (over 99% pure as determined by HPLC) were characterized by 1H NMR and negative ion electrospray ionization mass spectrometry.

Chromatography, High Pressure Liquid↗

PubMed2002

Preparative isolation and purification of calycosin from Astragalus membranaceus Bge. var. mongholicus (Bge.) Hsiao by high-speed counter-current chromatography.

Calycosin was purified from an ethyl acetate extract of the root of Astragalus membranaceus Bge. var. mongholicus (Bge.) Hsiao by high-speed counter-current chromatography. The separation was performed in two steps with a two-phase solvent system composed of n-hexane-chloroform-methanol-water (1:3:3:2, v/v). From 200 mg of the crude extract, 14.8 mg of calycosin was obtained at over 99% purity as determined by HPLC analysis, and its chemical structure was confirmed by MS, 1H and 13C nuclear magnetic resonance.

Astragalus Plant↗

PubMed2002

Purification of icariin from the extract of Epimedium segittatum using high-speed counter-current chromatography.

Icariin was purified from the extract of Epimedium segittatum by high-speed counter-current chromatography with a two-phase solvent system composed of n-hexane-n-butanol-methanol-water (1:4:2:6, v/v). We used two multilayer coil planet centrifuges with different capacities. A 300 mg amount of the extract was separated using a semipreparative instrument equipped with a 230-ml capacity column to yield 103 mg of icariin at 86.2% purity. An 8 g amount of the extract was separated with a large preparative instrument equipped with a 2460-ml capacity column to produce 2.45 g of icariin at 85.7% purity. From these fractions over 98% pure icariin was obtained by recrystallization with water.

Chromatography, High Pressure Liquid↗

PubMed2002

Purification of Food Color Red No. 106 (acid red) using pH-zone-refining counter-current chromatography.

pH-Zone-refining counter-current chromatography was successfully applied to the separation of the main components of Food Color Red No. 106 (R-106, acid red, Color Index No. 45100). A 300-mg quantity of sample was separated using the following two-phase solvent system: n-butanol-water, 40 mM sulfuric acid in organic stationary phase and 30 mM ammonia in aqueous mobile phase. The obtained fractions were analyzed by high-performance liquid chromatography and fast atom bombardment mass spectrometry. The separation yielded 261.9 mg of main component of acid red with purity of 99.9%.

Chromatography, High Pressure Liquid↗

PubMed2002

Separation of tanshinones from Salvia miltiorrhiza bunge by multidimensional counter-current chromatography.

Analytical and preparative high-speed counter-current chromatography (HSCCC) was successfully used for the isolation and purification of tanshinones from the roots of Salvia miltiorrhiza Bunge. Using multidimensional HSCCC, four major components including tanshinone IIA (16 mg), tanshinone I (10 mg), dihydrotanshinone I (7 mg) and cryptotanshinone (11 mg) were isolated each at high purity of over 95%.

Abietanes↗

PubMed2002

Preparative separation of lappaconitine, ranaconitine, N-deacetyllappaconitine and N-deacetylranaconitine from crude alkaloids of sample Aconitum sinomontanum Nakai by high-speed counter-current chromatography.

Analytical high-speed counter-current chromatography (HSCCC) was used for the systematic selection and optimization of the two-phase solvent system to separate alkaloids from Aconitum sinomontanum Nakai. The optimum solvent systems CHCl3-MeOH-0.3 M/0.2 M HCl (4:1.5:2, v/v) thus obtained led to the successful separation of lappaconitine, ranaconitine, N-deacetyllappaconitine and N-deacetylranaconitine from 60 to 500 mg of crude alkaloid sample by preparative HSCCC separation.

Aconitine↗

PubMed2002

Method for the fractionation of dextran by centrifugal precipitation chromatography.

Recent advances in biotechnology and biochemistry have been facilitated by efficient separation methods for biopolymers, such as proteins and nucleic acids. On the other hand, research on polysaccharides is hindered by problems in their fractionation. For many decades, polysaccharides have been fractionated by stepwise ethanol precipitation, and even at the present time, almost all of their purification protocols include at least one such step, although it is tedious and inefficient. This paper describes a novel approach for chromatographic fractionation of polysaccharides by ethanol gradient precipitation using an open column under a centrifugal force field. Using a unique column design, chromatographic separation of polymers is achieved by subjecting the sample to a repetitive process of precipitation and dissolution along a long, spiral channel. In this article, we fully describe the principle, design of the prototype, and basic studies on various parameters for optimization of chromatographic conditions, using dextran as an example.

Chromatography↗

PubMed2002

Staphylococcal scalded-skin syndrome in an adult due to methicillin-resistant Staphylococcus aureus.

We report a case of a 71-year-old man with staphylococcal scalded-skin syndrome (SSSS). The patient, with a chronic history of diabetes mellitus, was admitted to our hospital with lumbago, and a diagnosis of renal-cell carcinoma with bone metastasis was made. In hospital he had sudden onset of high fever and erythema, followed by the formation of flaccid bullae and exfoliation, with a positive Nikolsky sign. Methicillin-resistant Staphylococcus aureus (MRSA), producing exfoliative toxin B, was isolated from blood and bile cultures, and Aeromonas hydrophila was isolated from bile culture. Skin biopsy specimen showed a cleavage of the epidermis at the level of the granular layer. The patient was diagnosed as having SSSS and cholecystitis, and was treated with intravenous antibiotics and percutaneous transhepatic gallbladder drainage, which led to recovery. SSSS in adults is usually associated with immunosuppression. A. hydrophila is recognized as an opportunistic pathogen. SSSS should be considered in the differential diagnosis of immunocompromised adult patients with sudden onset of high fever and erythema.

Aeromonas hydrophila↗

PubMedDate not supplied

Preparative fractionation of protein, RNA, and plasmid DNA using centrifugal precipitation chromatography with tubular dialysis membrane inside a convoluted tubing as separation channel.

Fractionation of clarified E. coli lysate components in bench-scale and preparative-scale centrifugal precipitation chromatography (CPC), using a solution of cationic surfactant cetyltrimethylammonium bromide (CTAB) containing 0.5 M NaCl as precipitant, are compared here. Step gradient of CTAB from 0.50% to 0.16% (w/v) gave a successful fractionation in bench-scale CPC; however, a linear gradient of lower CTAB concentration, 0.20-0% (w/v), was used in the preparative scale and resulted in similar fractionation. The preparative-scale CPC has a superior sample loading capacity by the use of tubular dialysis membrane inside convoluted tubing as the separation channel. In this study, the quantity of the sample loaded into the preparative CPC was about 15 times more than that in the bench scale, and in a single run the preparative CPC could prepare approximately 3 mg of plasmid DNA with about 96% of RNA removed. The higher surface area per length of the separation channel in the preparative CPC was believed to benefit mass transfer of CTAB across the membrane, leading to less CTAB being required in the process.

Centrifugation↗