376
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Adachi A, Sawada S, Shida K, Nakamura E, Okano T. Determination of Vanadium in Foods by Atomic Absorption Spectrophotometry. ANAL LETT 1999. [DOI: 10.1080/00032719908542973] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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377
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Yamaguchi Y, Nishimura K, Okano T, Yoshitake K. One and three year prospective study of treatment of temporomandibular joint dysfunction by intraoral vertical ramus osteotomy. Int J Oral Maxillofac Surg 1999. [DOI: 10.1016/s0901-5027(99)80721-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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378
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Yamato M, Okuhara M, Karikusa F, Kikuchi A, Sakurai Y, Okano T. Signal transduction and cytoskeletal reorganization are required for cell detachment from cell culture surfaces grafted with a temperature-responsive polymer. JOURNAL OF BIOMEDICAL MATERIALS RESEARCH 1999; 44:44-52. [PMID: 10397903 DOI: 10.1002/(sici)1097-4636(199901)44:1<44::aid-jbm5>3.0.co;2-x] [Citation(s) in RCA: 122] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We have developed a new cell culture substrate grafted with a temperature-responsive polymer, poly(N-isopropylacrylamide) (PIPAAm) using an electron beam irradiation method. These surfaces are hydrophobic in culture at 37 degrees C due to the hydration/dehydration changes intrinsic to PIPAAm at 32 degrees C, and they become highly hydrophilic below 32 degrees C. At 37 degrees C grafted and ungrafted surfaces showed no difference with regard to attachment, spreading, growth, confluent cell density, and morphology of bovine aortic endothelial cells. Stress fibers, peripheral bands, and focal contacts were established in similar ways. After the medium temperature was decreased to 20 degrees C, spread cells lost their flattened morphology, acquiring a rounded cell appearance similar to that of cells immediately after plating. After mild agitation cells floated free from the dish surface without trypsin treatment. Neither cell morphological changes nor cell detachment occurred on ungrafted surfaces. An ATP synthesis inhibitor, sodium azide, and a tyrosine kinase inhibitor, genistein, suppressed cell morphological changes and cell detachment while a protein synthesis inhibitor, cycloheximide, slightly enhanced cell detachment. An actin filament stabilizer, phalloidin, and its depolymerizer, cytochalasin D, also inhibited cell detachment. These findings suggest that cell detachment on grafted surfaces is mediated by intracellular signal transduction and reorganization of the cytoskeleton. While trypsinization causes damage to the cell membrane surface and extracellular matrix proteins, this alternative low temperature treatment is exceptionally noninvasive. The temperature-responsive cell culture surface also should prove useful for investigating the molecular machinery involved in cell-surface detachment.
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379
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Okano T, Midorikawa Y, Kitajima T. [Influence of nitric oxide on cerebral hemodynamics during endotoxemia in dogs]. MASUI. THE JAPANESE JOURNAL OF ANESTHESIOLOGY 1999; 48:27-31. [PMID: 10036885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
The aim of this study is to clarify the influence of nitric oxide (NO) in cerebral circulation during endotoxemia. Two groups of 24 mongrel dogs (N = 12 each) received saline 1 ml.kg-1.h-1 or endotoxin (lipopolysaccharide, LPS) 500 ng.kg-1.h-1 for 3 hours. To determine changes of NO in the systemic and cerebral circulation, we measured NOx (NO2-/NO3-) in the femoral artery and superior sagittal sinus as metabolites of NO using the Griess method. We also measured the concentrations of cerebral oxyhemoglobin (HbO2), deoxyhemoglobin (Hb), total hemoglobin (total Hb) and cytochrome aa3 (Cytaa3) using near-infrared laser spectroscopy. Changes in cerebral blood volume were evaluated from the total Hb. NOx in systemic and cerebral circulation increased significantly after infusion of LPS. Therefore, the increased production of NO in cerebral circulation was consistent with increase of cerebral blood volume. In conclusion, it seems reasonable to assume that increased cerebral blood volume may result from increased production of cerebral NO during endotoxemia.
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380
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Tsugawa N, Yamabe T, Takeuchi A, Kamao M, Nakagawa K, Nishijima K, Okano T. Intestinal absorption of calcium from calcium ascorbate in rats. J Bone Miner Metab 1999; 17:30-6. [PMID: 10084399 DOI: 10.1007/s007740050060] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
The intestinal absorption of calcium (Ca) from Ca ascorbate (Ca-AsA) was investigated in normal rats. Each animal was perorally administered either 5mg (low dose) or 10mg (high dose) of Ca in 1ml of distilled water as Ca-AsA, Ca carbonate (CaCO3), or Ca chloride (CaCl2), which were intrinsically labeled with 45Ca using 45CaCl2. The amount of radioactivity in plasma was measured periodically up to 34h after dosing, and pharmacokinetic parameters were calculated from the radioactivity in plasma. The time taken to reach the maximum 45Ca level (Tmax) did not differ among the three groups. The area under the plasma 45Ca level/time curve (AUCinfinity) value for the Ca-AsA group was significantly higher than those for the CaCO3 and the CaCl2 groups. The radioactivity at Tmax (Cmax) for the Ca-AsA group was significantly higher than those for the CaCO3 and the CaCl2 groups for the low dose, and comparable with or significantly higher than those for the CaCl2 and CaCO3 groups for the high dose. Similar results were observed for whole-body 45Ca retention. Radioactivity in the femur 34h after dosing was the highest in the Ca-AsA group and the lowest in the CaCO3 group. The rank order of solubility in water, the first fluid (pH 1.2, JP-1) of JPXIII disintegration medium, acetate buffer solution (pH 4.0), triethanolamine-malate buffer solution (pH 7.0) and ammonium chloride buffer solution (pH 10.0) at 37 degrees C was CaCl2 > Ca-AsA > CaCO3. In contrast, the rank order of the solubility in the second fluid (pH 6.8, JP-2) of JPXIII disintegration medium at 37 degrees C was Ca-AsA > CaCl2 > CaCO3. These results indicate that the absorbability of Ca from Ca-AsA is almost comparable with, or higher than, that from CaCl2 and significantly higher than that from CaCO3 because of its high degree of solubility in the intestine. Therefore, Ca-AsA would be useful as a Ca supplement with relatively high absorption from intestine.
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381
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von Recum H, Kikuchi A, Okuhara M, Sakurai Y, Okano T, Kim SW. Retinal pigmented epithelium cultures on thermally responsive polymer porous substrates. JOURNAL OF BIOMATERIALS SCIENCE. POLYMER EDITION 1998; 9:1241-53. [PMID: 9860183 DOI: 10.1163/156856298x00758] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A cross-linkable co-polymer of UV-sensitive 4-(N-cinnamoylcarbamide)methylstyrene (CCMS) and N-isopropylacrylamide (NIPAAm), was applied to porous tissue culture inserts. Surface chemical analyses of the inserts show an introduction of a thermally responsive polymer comparable to that on similarly incorporated non-porous polystyrene surfaces. Contact angle measurements as well as atomic force microscopy show a surface change in response to changing temperature in an aqueous environment, from hydrophilic, extended polymer chains below 32 degrees C to a dense hydrophobic film above 32 degrees C. Cell growth on porous inserts allowed measurement of cell expression, such as transepithelial resistance and fluid transport, which are not observable on cells from non-porous surfaces. Cultures of retinal pigmented epithelium (RPE) were able to restore an environment similar to in vivo by forming a tight junction barrier membrane upon confluence at 37 degrees C, as observed by changes in morphology, transepithelial resistance, and directionally-specific fluid transport. In addition, cells cultured on these surfaces detached as an oriented polarized sheet when the inserts were brought to 20 degrees C. This cell sheet was transplanted to other tissue culture surface without polymer detachment or dissolution, or cell damage caused by traditional detachment methods using proteolytic enzymes.
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382
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Kikuchi A, Okuhara M, Karikusa F, Sakurai Y, Okano T. Two-dimensional manipulation of confluently cultured vascular endothelial cells using temperature-responsive poly(N-isopropylacrylamide)-grafted surfaces. JOURNAL OF BIOMATERIALS SCIENCE. POLYMER EDITION 1998; 9:1331-48. [PMID: 9860173 DOI: 10.1163/156856298x00424] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Temperature-responsive hydration/dehydration changes in surface-grafted poly(N-isopropylacrylamide) (PIPAAm) were utilized for hydrophilic/hydrophobic surface property alterations in cell culture. In this report, we utilized PIPAAm-grafted surfaces to recover confluently-cultured vascular endothelial cells as coherent monolayers from this cell culture substrate and to transfer to new cell culture substrates. For this purpose, we used two different methods to recover and transfer cell monolayer cultures: (1) chitin membranes used as an apical side cell support during cultured cell transfer, allowing cell basal side reattachment to new culture substrates after transfer; and (2) a cell culture insert (porous PET) used as both a support as well as new substrate, allowing basal surfaces of cultured cells to be exposed to the medium after transfer. In both cases, all cells grown on PIPAAm-grafted surfaces detach completely with maintenance of basement membrane-like structure. Recovered cells attach to the second culture surfaces, covering more than 60% of the new substrate, and retain approximately 90% viability and their original function as judged from tissue-type plasminogen activator secretion. This technique could be utilized to prepare novel bioartificial organs as well as cell co-culture systems by multi-layering different cell types to mimic tissue structures for tissue engineering.
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383
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Yu BG, Okano T, Kataoka K, Sardari S, Kwon GS. In vitro dissociation of antifungal efficacy and toxicity for amphotericin B-loaded poly(ethylene oxide)-block-poly(beta benzyl L aspartate) micelles. J Control Release 1998; 56:285-91. [PMID: 9801451 DOI: 10.1016/s0168-3659(98)00095-9] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Amphotericin B (AmB) is a membrane-active drug used frequently for the treatment of systemic fungal diseases. Limitations for the use of AmB include poor water solubility and potential for serious systemic toxicities. Recently, it has been demonstrated that the aggregation state of AmB is a determinant factor for toxicity. To increase its therapeutic index, AmB has been solubilized in micelles based on poly(ethylene oxide)-block-poly(beta-benzyl-l-aspartate) (PEO-block-PBLA), using a dialysis method of drug loading. The aggregation state of AmB has been investigated by electronic absorption spectroscopy. AmB loaded in PEO-block-PBLA micelles is non-hemolytic for concentrations up to 15 microgram/ml. AmB as Fungizone(R) initiates hemolysis at 1.0 microgram/ml. The onset of hemolysis correlates with the respective critical aggregation concentrations (CACs) of AmB. The antifungal activity of the AmB-loaded PEO-block-PBLA micelles is four to eight times higher than Fungizone(R) in terms of minimal inhibitory concentrations (MICs). PEO-block-PBLA has no antifungal activity for concentrations up to 200 microgram/ml. The basis for the increase in antifungal activity of AmB-loaded PEO-block-PBLA micelles is unclear, but may be related to a stabilizing effect of the polymeric micelles against auto-oxidation of the AmB heptaene moiety or alternatively, an enhancement in membrane perturbation of fungal cells.
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384
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Ono Y, Kawase A, Watanabe H, Shiraishi A, Takeda S, Higuchi Y, Sato K, Yamauchi T, Mikami T, Kato M, Tsugawa N, Okano T, Kubodera N. Syntheses and preventive effects of analogues related to 1alpha,25-dihydroxy-2beta-(3-hydroxypropoxy)vitamin D3 (ED-71) on bone mineral loss in ovariectomized rats. Bioorg Med Chem 1998; 6:2517-23. [PMID: 9925307 DOI: 10.1016/s0968-0896(98)80025-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Analogues related to 1alpha,25-dihydroxy-2beta-(3-hydroxypropoxy)vitamin D3 (ED-71) (2), 26,27-dimethyl ED-71 (3) and 26,27-diethyl ED-71 (4), were synthesized from lithocholic acid (5). In the study of the preventive effects of these analogues and ED-71 (2) on bone mineral loss in ovariectomized rats, 26,27-dimethyl ED-71 (3) showed the most potent activity.
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385
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Helbert W, Nishiyama Y, Okano T, Sugiyama J. Molecular imaging of halocynthia papillosa cellulose. J Struct Biol 1998; 124:42-50. [PMID: 9931272 DOI: 10.1006/jsbi.1998.4045] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The molecular organization of cellulose Ibeta microfibrils in the tunic of Halocynthia papillosa was analyzed by high-resolution cryoelectron microscopy on ultrathin cross sections of artificially highly oriented microfibrils. The arrangement of cellulose chains intersected by the 0.6-, 0.53-, and 0.39-nm equatorial lattice planes was clearly imaged over the whole area of a parallelogram-shaped cross section of a microfibril. One, edge of the parallelogram was parallel to the 0.6-nm lattice plane, while the other did not correspond to a crystallographic plane. Such organization is distinct from previous findings on algal cellulose Ialpha-rich microfibrils, which have an almost square cross section bounded by both 0.6- and 0.53-nm crystallographic planes. A tentative model for microfibril formation is proposed by introducing a two-step biocrystallization mechanism: the formation of molecular sheets spaced by 0.53 nm between adjacent molecules, followed by self-deposition of these sheets by hydrogen bonding between them. Copyright 1998 Academic Press.
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386
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Okano T, Nakagawa K, Tsugawa N, Ozono K, Kubodera N, Osawa A, Terada M, Mikami K. Singly dehydroxylated A-ring analogues of 19-nor-1alpha,25-dihydroxyvitamin D3 and 19-nor-22-oxa-1alpha,25-dihydroxyvitamin D3: novel vitamin D3 analogues with potent transcriptional activity but extremely low affinity for vitamin D receptor. Biol Pharm Bull 1998; 21:1300-5. [PMID: 9881643 DOI: 10.1248/bpb.21.1300] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
1Alpha,25-dihydroxyvitamin D3 [1alpha,25(OH)2D3] mediates its biological activities through specific binding to the nuclear vitamin D receptor (VDR). The VDR, bound to 1alpha,25(OH)2D3, forms a heterodimer with a nuclear accessory factor, retinoid X receptor (RXR), and the complex subsequently binds to specific nucleotide sequences or a vitamin D-responsive element (VDRE) to induce gene transcriptions. Thus, an ideal analogue of 1alpha,25(OH)2D3 for therapeutic applications has been considered to be one which has a high binding affinity for VDR, thus forming a stable VDR/RXR complex, and binding strongly to VDRE. By contrast, we report here evidence contrary to this hypothesis. Several singly dehydroxylated A-ring analogues of 19-nor-1alpha,25-dihydroxyvitamin D3 and 19-nor-22-oxa-1alpha,25-dihydroxyvitamin D3, all of which have an extremely low binding affinity for VDR, and some of which lack the 1alpha-hydroxyl group that is considered to be essential for VDR-mediated gene expression, have greater or equivalent potencies to 1alpha,25(OH)2D3 for inhibiting the proliferation and inducing the differentiation of HL-60 cells, as well as inducing the transactivation of a luciferase reporter gene combining a rat 25-hydroxyvitamin D3 24-hydroxylase gene promoter containing two VDREs. The present findings open interesting possibilities as to the role of the VDR in the genomic action of 1alpha,25(OH)2D3 and the development of new 19-nor-analogues of 1alpha,25(OH)2D3.
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387
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Yokoyama M, Okano T. [Targeting of anti-cancer drugs with nano-sized carrier system]. NIHON RINSHO. JAPANESE JOURNAL OF CLINICAL MEDICINE 1998; 56:3227-34. [PMID: 9883646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Feasibility of anticancer drug targeting to solid tumors with nano-sized drug carrier systems by a passive targeting mechanism is discussed. Selective delivery to solid tumor sites can be done by utilizing EPR effect (Enhanced Permeability and Retention effect) of solid tumor sites. Essential factors of carriers systems based on this mechanism is size and chemical character of carriers. Size and chemical character must be in a range of several nm to 200 nm and neutral or weakly negatively charged surface, respectively. Present status and future perspective of four types of nano-carrier systems (water-soluble polymer, nanosphere, liposome, and polymeric micelle) are described with recent developments of each system.
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388
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Ohtani M, Tsugawa N, Kamao M, Okano T. Absorbability of calcium from a new calcium supplement prepared from bovine marrow-free bone in rats. J Nutr Sci Vitaminol (Tokyo) 1998; 44:887-95. [PMID: 10197319 DOI: 10.3177/jnsv.44.887] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Powdered bovine marrow-free bone was completely solubilized with lactic and citric acids under reduced pressure. The resulting solution was lyophilized to obtain a stable powder form (total bone extract, TBE), and the calcium (Ca) absorbability of TBE from intestine was investigated in normal rats. Each animal perorally received 10 mg of Ca in 1 mL of distilled water as extrinsic 45Ca-labeled TBE, intrinsic 45Ca-labeled Ca lactate, or intrinsic 45Ca-labeled Ca carbonate. The amount of radioactivity in plasma was measured periodically up to 34 h after dosing, and pharmacokinetic parameters were calculated from the radioactivity in plasma. The time taken to reach the maximal 45Ca level (Tmax) did not differ among the three groups. The area under the plasma 45Ca level/time curve (AUC infinity) and the radioactivity at Tmax (Cmax) values for the TBE group were significantly higher than those of the Ca carbonate group. Similar results were observed between the Ca lactate and the Ca carbonate groups. No significant difference was observed in the AUC infinity and the Cmax values between the TBE and the Ca lactate groups. Radioactivity in a femur 34 h after dosing was highest in the Ca lactate group and lowest in the Ca carbonate group among the three groups. Both the TBE and the Ca lactate groups showed significant higher whole-body 45Ca retention than the Ca carbonate group did, although no significant difference was found between the TBE and the Ca lactate groups. These findings indicate that the Ca absorbability of TBE is almost comparable with that of Ca lactate and higher than that of Ca carbonate. Therefore TBE would be useful as a Ca supplement with relatively high absorbability from intestine.
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389
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Adachi A, Ikeda C, Takagi S, Fukao N, Yoshii E, Okano T. Studies on removal efficiency of chloroform from tap water by rice bran. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 1998; 55:385-387. [PMID: 9829561 DOI: 10.1080/009841098158421] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Removal efficiency of chloroform from tap water by rice bran was investigated. The adsorption rate by rice bran was similar to activated carbon. The amount of chloroform adsorbed was plotted against the equilibrium concentration of chloroform in solution on a logarithmic scale. A linear relationship was obtained, indicating that the adsorption reaction was a Freundlich type. The adsorption of chloroform by rice bran was observed in the range of pH 1-11. Chloroform was successfully removed from tap water with average removal efficiency of 70% after 60 min when rice bran was applied to tap water that contained 0.0064 mg/L chloroform.
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390
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von Recum H, Okano T, Wan Kim S. Growth factor release from thermally reversible tissue culture substrates. J Control Release 1998; 55:121-30. [PMID: 9795028 DOI: 10.1016/s0168-3659(98)00042-x] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Thermally reversible poly(N-isopropylacrylamide) (PIPAAm) was covalently grafted onto tissue culture dishes to allow detachment of cultured cells upon temperature change from physiological to room temperature. In addition the grafted polymer matrix was used to entrap biomolecules such as growth factors either to be released by diffusion early in cell cultures, or remain entrapped and be reversibly exposed to cell receptors. Experiments with model proteins trypsin and insulin show that amount loaded and released depends upon the PIPAAm grafting density. Dishes grafted with 2.5 microgram/cm2 PIPAAm released approximately four times more model protein over 4 h than dishes grafted with 1.8 microgram/cm2. This in vitro drug delivery system can be used to deliver factors to the basal side of cells early in cell culture by providing high local concentrations without high bulk concentration. Cultures of human retinal pigmented epithelium showed higher growth rate on insulin loaded dishes than on controls containing a similar bulk solution concentration. These cultures retained the ability to detach singly or as confluent sheets from the loaded surfaces.
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391
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Yokoyama M, Satoh A, Sakurai Y, Okano T, Matsumura Y, Kakizoe T, Kataoka K. Incorporation of water-insoluble anticancer drug into polymeric micelles and control of their particle size. J Control Release 1998; 55:219-29. [PMID: 9795065 DOI: 10.1016/s0168-3659(98)00054-6] [Citation(s) in RCA: 162] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
A water-insoluble anticancer drug, KRN 5500 (KRN), was incorporated into polymeric micelles forming from poly(ethylene glycol-poly(amino acid) block copolymers by physical entrapment utilizing hydrophobic interactions between this drug and the poly(amino acid) chain block of the block copolymers. Three block copolymers were examined for this incorporation; poly(ethylene glycol)-poly(beta-benzyl l-aspartate) (PEG-PBLA) and its two derivatives obtained by partial hydrolysis at the beta-benzyl l-aspartate (BLA) units (PEG-P(Asp, BLA)) and by partial cetyl ester substitution at the BLA units (PEG-P(C16, BLA)), respectively. Among these block copolymers, considerable effects of the cetyl esterification were seen on KRN yield and particle size. Considerable differences in the KRN incorporation yield and particle size were also observed between DMF and DMS used as solvent to dissolve KRN and the block copolymers. Sonication was turned out to be an effective method to obtain a polymer micelles fraction in high efficiency, and sonication was considered to work for separating intermicellar associates into dispersed micelles. A KRN incorporation procedure by dialysis using PEG-P(C16, BLA) and DMSO (as solvent) followed by sonication brought about polymeric micelles of 71 nm in weight-average diameter. This shows successful incorporation of a water-insoluble drug into polymeric micelles by optimizing block copolymer structure and incorporation conditions.
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392
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Liaw J, Aoyagi T, Kataoka K, Sakurai Y, Okano T. Visualization of PEO-PBLA-pyrene polymeric micelles by atomic force microscopy. Pharm Res 1998; 15:1721-6. [PMID: 9833994 DOI: 10.1023/a:1011908728838] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
PURPOSE To directly visualize and evaluate the aqueous block copolymeric micelles, poly(ethylene oxide)-poly(beta-benzyl L-aspartate) (PEO-PBLA) chemically conjugated with pyrene fluorescence molecule, by nanotechnology of atomic force microscopy (AFM). METHODS The block copolymers' PEO-PBLA-Pyrene was first synthesized by reacting with pyrene sulfonyl chloride and PEO-PBLA in tetrahydrofuran (THF) solution and were identified by GPC reflect index, UV and fluorescence detectors. The characterization of physical and chemical properties of PEO-PBLA-Pyrene polymeric micellar solution were examined by the dynamic light scattering (DLS) and critical micelles concentrations (CMC). In addition, the nanotechnology of AFM was used to directly visualize the size and shape of nanopolymeric micelles. RESULTS The pyrene fluorescence molecule were successfully conjugated at the amino group of the end of PBLA chain by GPC with three different detectors. The size of the aqueous PEO-PBLA-Pyrene polymeric micelles was detected around 57 nm with unimodal distribution by DLS measurement. As a result of this finding, the CMC test was also found out that the fluorescence intensity was increasing around 0.01 approximately 0.05 mg/ml. Using AFM evaluation of polymeric micellar solution, the morphology of aqueous PEO-PBLA-Pyrene polymeric micelles was observed on round shape and with the narrow dispersity of size range 50 approximately 80 nm. CONCLUSIONS The presence of PEO-PBLA copolymers with pyrene in an aqueous system formed in a spherical and nano range of polymeric micelles.
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393
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Kohori F, Sakai K, Aoyagi T, Yokoyama M, Sakurai Y, Okano T. Preparation and characterization of thermally responsive block copolymer micelles comprising poly(N-isopropylacrylamide-b-DL-lactide). J Control Release 1998; 55:87-98. [PMID: 9795019 DOI: 10.1016/s0168-3659(98)00023-6] [Citation(s) in RCA: 236] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The thermally sensitive block copolymer, poly(N-isopropylacrylamide-b-dl-lactide) (PIPAAm-PLA), was synthesized by ring-opening polymerization of dl-lactide initiated from hydroxy-terminated poly (N-isopropylacrylamide) (PIPAAm). A PIPAAm bearing a single terminal hydroxyl group was prepared by telomerization using 2-hydroxyethanethiol as a chain-transfer agent. Successful preparation of PIPAAm and the PIPAAm-PLA block copolymer was verified by gel permeation chromatography (GPC) and 1H-NMR spectroscopy. Polymeric micelles were prepared from block copolymers using a dialysis method. Their solutions showed reversible changes in optical properties: transparent below a lower critical solution temperature (LCST) and opaque above the LCST. Dynamic light scattering measurements were used to observe the formation of micellar structures approximately 40 nm in diameter, which do not change between 20 degreesC and 30 degreesC. Above the LCST, polymer micelles aggregated, a phenomenon found to be reversible since the aggregates dissociated again by cooling below the LCST. Further observations using atomic force microscopy (AFM) confirmed this behaviour. The properties of this block copolymer system are interesting from both applied and fundamental perspectives, particularly for active targeting as drug carriers.
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394
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Katsura Y, Okano T, Noritake M, Kosano H, Nishigori H, Kado S, Matsuoka T. Hepatocyte growth factor in vitreous fluid of patients with proliferative diabetic retinopathy and other retinal disorders. Diabetes Care 1998; 21:1759-63. [PMID: 9773744 DOI: 10.2337/diacare.21.10.1759] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE To determine whether hepatocyte growth factor (HGF) is elevated in the vitreous fluid of patients with proliferative diabetic retinopathy (PDR). RESEARCH DESIGN AND METHODS Vitreous fluid samples were obtained at the time of vitreoretinal surgery from 73 eyes of PDR patients and from 17 eyes of nondiabetic patients (control subjects) who had macular hole, rhegmatogenous retinal detachment, or epiretinal membrane (9, 4, and 4 eyes, respectively) but no associated proliferative vitreoretinopathy Stages of PDR were classified as active or quiescent. Concentrations of HGF and vascular endothelial growth factor (VEGF) in vitreous fluid were determined by enzyme-linked immunosorbent assay (ELISA). RESULTS Intravitreous concentrations of HGF (median [range]) were significantly higher in diabetic patients with PDR (6.00 ng/ml [0.75-22.21) than in control patients (2.86 ng/ml [0.75-5.801). Intravitreous concentrations of VEGF were also higher in diabetic patients with PDR (1.62 ng/ml [0.15-7.91) than in control patients (0.16 ng/ml [0.160.29]). Both VEGF and HGF concentrations were significantly higher in patients with active retinopathy than in those with quiescent retinopathy However, vitreous concentrations of HGF were unrelated to those of VEGE CONCLUSIONS: We found that levels of HGF in vitreous fluid of PDR patients are significantly higher than in nondiabetic patients and that the levels of HGF are elevated in the active PDR stage. This suggests that HGF stimulates or perpetuates neovascularization in PDR.
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Ito E, Suzuki K, Yamato M, Yokoyama M, Sakurai Y, Okano T. Active platelet movements on hydrophobic/hydrophilic microdomain-structured surfaces. JOURNAL OF BIOMEDICAL MATERIALS RESEARCH 1998; 42:148-55. [PMID: 9740017 DOI: 10.1002/(sici)1097-4636(199810)42:1<148::aid-jbm18>3.0.co;2-h] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The early motion and interaction of platelets on a microdomain-structured block copolymer surface composed of 2-hydroxyethyl methacrylate (HEMA)-styrene were analyzed and compared with those on a compositionally identical random copolymer, homopolymer poly (HEMA) (hydrophilic) and polystyrene (hydrophobic) surfaces. Contacting platelets were quantitatively more active, with motions including rolling, detachment, oscillatory vibration, and change of direction only on the HEMA-St block copolymer surface. Active platelet movements were observed for long time periods (>20 min) on HEMA-St block copolymer surfaces and were distinct from those for inert PSt latex particles on these same surfaces, demonstrating that platelet movements were not due to physical forces such as convection, hydrophobic interactions, or microbrownian movement. To study the cause and mechanism underlying the platelet movements, platelets treated with an adenosine triphosphate (ATP) synthesis inhibition, NaN3, or a membrane skeleton-disrupting chemical agent, dibucaine, were also studied on these surfaces. Both treatments reduced platelet movement and demonstrated that platelets in contact with the HEMA-St block copolymer surface require metabolic processes consuming ATP and involve dynamics of their membrane skeleton. These energy-consuming active movements might explain the previously observed lower platelet activation and low thrombogenicity of the HEMA-St block copolymers. Enhanced platelet movements on the HEMA-St block copolymer surface show that the microdomain surface interacts uniquely with platelets to hinder activation and preserve passive platelet function despite surface contact.
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396
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Okano T, Matsuda T. Muscular tissue engineering: capillary-incorporated hybrid muscular tissues in vivo tissue culture. Cell Transplant 1998. [PMID: 9786063 DOI: 10.1016/s0963-6897(98)00030-x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023] Open
Abstract
Requirements for a functional hybrid muscular tissue are 1) a high density of multinucleated cells, 2) a high degree of cellular orientation, and 3) the presence of a capillary network in the hybrid tissue. Rod-shaped hybrid muscular tissues composed of C2C12 cells (skeletal muscle myoblast cell line) and type I collagen, which were prepared using the centrifugal cell-packing method reported in our previous article, were implanted into nude mice. The grafts, comprised three hybrid tissues (each dimension, diameter, approximately 0.3 mm, length, approximately 1 mm, respectively), were inserted into the subcutaneous spaces on the backs of nude mice. All nude mice that survived the implantation were sacrificed at 1, 2, and 4 wk after the implantation. The grafts were easily distinguishable from the subcutaneous tissues of host mice with implantation time. The grafts increased in size with time after implantation, and capillary networks were formed in the vicinities and on the surfaces of the grafts. One week after implantation, many capillaries formed in the vicinities of the grafts. In the central portion of the graft, few capillaries and necrotic cells were observed. Mononucleated myoblasts were densely distributed and a low number of multinucleated myotubes were scattered. Two weeks after implantation, the formation of a capillary network was induced, resulting in the surfaces of the grafts being covered by capillaries. Numerous elongated multinucleated myotubes and mononucleated myoblasts were densely distributed and numerous capillaries were observed throughout the grafts. Four weeks after implantation a dense capillary network was formed in the vicinities and on the surfaces of the grafts. In the peripheral portion of the graft, multinucleated myotubes in the vicinities of the rich capillaries were observed. Thus, hybrid muscular tissues in vitro preconstructed was remodeled in vivo, which resulted in facilitating the incorporation of capillary networks into the tissues.
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397
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Kametaka S, Okano T, Ohsumi M, Ohsumi Y. Apg14p and Apg6/Vps30p form a protein complex essential for autophagy in the yeast, Saccharomyces cerevisiae. J Biol Chem 1998; 273:22284-91. [PMID: 9712845 DOI: 10.1074/jbc.273.35.22284] [Citation(s) in RCA: 226] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mutation in the Saccharomyces cerevisiae APG14 gene causes a defect in autophagy. Cloning and structural analysis of the APG14 gene revealed that APG14 encodes a novel hydrophilic protein with a predicted molecular mass of 40.5 kDa, and that Apg14p has a coiled-coil motif at its N terminus region. We found that overproduction of Apg14p partially reversed the defect in autophagy induced by the apg6-1 mutation. The apg6-1 mutant was found to be defective not only in autophagy but also in sorting of carboxypeptidase Y (CPY), a vacuolar-soluble hydrolase, to the vacuole. However, overexpression of APG14 did not alter the CPY sorting defect of the apg6-1 mutant, nor did the apg14 null mutation affect the CPY sorting pathway. Structural analysis of APG6 revealed that APG6 is identical to VPS30, which is involved in a retrieval step of the CPY receptor, Vps10p, to the late-Golgi from the endosome (Seaman, M. N. J., Marcusson, E. G., Cereghino, J. L., and Emr, S. D. (1997) J. Cell Biol. 137, 79-92). Subcellular fractionation indicated that Apg14p and Apg6p peripherally associated with a membrane structure(s). Apg14p was co-immunoprecipitated with Apg6p, suggesting that they form a stable protein complex. These results imply that Apg6/Vps30p has two distinct functions in the autophagic process and the vacuolar protein sorting pathway. Apg14p may be a component specifically required for the function of Apg6/Vps30p through the autophagic pathway.
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398
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Takahashi K, Nakamura N, Terada T, Okano T, Futami T, Saito H, Inui KI. Interaction of beta-lactam antibiotics with H+/peptide cotransporters in rat renal brush-border membranes. J Pharmacol Exp Ther 1998; 286:1037-42. [PMID: 9694966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Two H+/peptide cotransporters, PEPT1 and PEPT2, are expressed in the kidney, mediating the renal tubular reabsorption of oligopeptides and beta-lactam antibiotics. We examined the interactions of beta-lactam antibiotics with peptide transporters in rat renal brush-border membranes by evaluating the inhibitory potencies of the antibiotics against glycylsarcosine transport. Western blot analysis revealed that PEPT1 and PEPT2 were expressed in the renal brush-border membranes with the apparent molecular masses of 75 and 105 kDa, respectively. Using renal brush-border membrane vesicles, the uphill transport of glycylsarcosine was observed in the presence of an inward H+ gradient and an inside-negative membrane potential. Two transport systems with high affinity (Km of 50 microM) and low affinity (Km of 1.2 mM) appeared kinetically to mediate the glycylsarcosine uptake. The inhibition constants of the antibiotics for glycylsarcosine transport were more closely correlated with those in stable LLC-PK1 cells transfected with rat PEPT2 rather than PEPT1 cDNA. The beta-lactam antibiotics with an alpha-amino group showed trans-stimulation effects on the glycylsarcosine uptake, suggesting that these antibiotics and glycylsarcosine share a common peptide transporter. However, the antibiotics lacking an alpha-amino group failed to show the trans-stimulation effect. It is concluded that amino-beta-lactam antibiotics at therapeutic concentrations interact predominantly with PEPT2 localized in the brush-border membranes of rat kidney.
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399
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Kimura Y, Hanazawa T, Sano T, Okano T. Lateral retropharyngeal node metastasis from carcinoma of the upper gingiva and maxillary sinus. AJNR Am J Neuroradiol 1998; 19:1221-4. [PMID: 9726457 PMCID: PMC8332232] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Clinically unsuspected metastases to the lateral retropharyngeal nodes from carcinomas of the upper gingiva or maxillary sinus were found in five patients on follow-up CT examinations. Such uncommon metastases may follow the afferent lymphatic channels from the palate or pharyngeal region or arrive by retrograde lymphatics from positive neck nodes. Careful examination of lateral retropharyngeal nodes may be required in cancers of these primary sites.
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400
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Okano T, Beranek LL, Hidaka T. Relations among interaural cross-correlation coefficient (IACCE), lateral fraction (LFE), and apparent source width (ASW) in concert halls. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 1998; 104:255-265. [PMID: 9670524 DOI: 10.1121/1.423955] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Relations are determined between one of the important subjective attributes of concert hall acoustics, the apparent source width, ASW, and three acoustical measures, interaural cross-correlation coefficient IACCE, LFE, and strength factor G. Although these measures previously have been found to correlate with ASW, their relations with it have not been examined sufficiently, especially in respect to their frequency characteristics. Herein, ASW's are directly determined for electronically reproduced musical sound fields with extensive ranges of values for IACCE and LFE. Investigated as parameters are angles of incidence, the time delay difference between a pair of symmetric early lateral reflections, and the number of early lateral reflections. These studies indicate the relative efficacy of IACCE and LFE for determining ASW under conditions that are realistically encountered in concert halls. The results were compared with measured IACCE's, LFE's, and also the strength factor G's in existing concert halls. It is concluded that the arithmetic average of [1-IACCE]'s at 500, 1 k and 2 k Hz combined with the strength factor Glow of the sound field at frequencies below 250 Hz are physical measures highly correlated with the subjective rank ordering of concert halls and that they cover the effects on ASW of the entire octave-band frequency range from 125 to 4 k Hz.
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