Showing papers by "Yasuhiko Tabata published in 2010"
TL;DR: The promising of using mesenchymal stem cells as a targeted-delivery vehicle for cancer gene therapy, and various challenges and concerns regarding these therapies are examined.
163 citations
TL;DR: It is concluded that the PEG-modified complex is a promising t-PA delivery system to enhance the biological activity at the site necessary only by a local ultrasound irradiation.
93 citations
TL;DR: The long-term transfection efficiency of CP was higher than PEI25KDa as demonstrated by the in vitro cancer cell model, indicating the CP copolymer was a promising vector for the therapeutic gene delivery.
85 citations
TL;DR: In in‐vitro release studies in pH 7.0 PBS, salmon calcitonin was rapidly released from positively charged gelatin microspheres within 2 h, and its cumulative release was approximately 85%.
Abstract: The use of negatively and positively charged gelatin microspheres for pulmonary delivery of salmon calcitonin was examined in rats. The microspheres were prepared using acidic gelatin (isoelectric point (IEP):, 5.0) and basic gelatin (IEP, 9.0) for the negatively and positively charged microspheres, respectively. The average diameters of positively charged gelatin microspheres in the dry state were 3.4, 11.2, 22.5 and 71.5 μm, and that of negatively charged gelatin microspheres was 10.9 μm. Neither positively nor negatively charged gelatin microspheres underwent any degradation in pH 7.0 PBS and there was less than 8% degradation in bronchoalveolar lavage fluid (BALF) after 8 h. In in-vitro release studies in pH 7.0 PBS, salmon calcitonin was rapidly released from positively charged gelatin microspheres within 2 h, and its cumulative release was approximately 85%. In addition, the release profiles were not influenced by particle sizes. The release rates of salmon calcitonin from negatively charged gelatin microspheres were lower than that from positively charged gelatin microspheres. The cumulative release was approximately 40% after 2 h, but there was no evidence of any sustained release.
The pulmonary absorption of salmon calcitonin from gelatin microspheres was estimated by measuring its hypocalcaemic effect in rats. The pharmacological availability after administration of salmon calcitonin in positively and negatively charged gelatin microspheres was significantly higher than that in pH 7.0 PBS. The pharmacological availability after administration of salmon calcitonin in positively charged gelatin microspheres was significantly higher than that in negatively charged gelatin microspheres. Administration of salmon calcitonin in positively charged gelatin microspheres with smaller particle sizes led to a higher pharmacological availability. The pharmacological availability after pulmonary administration of salmon calcitonin in positively charged gelatin microspheres with particle sizes of 3.4 and 11.2 μm was approximately 50%.
In conclusion, the gelatin microspheres have been shown to be a useful vehicle for pulmonary delivery of salmon calcitonin.
57 citations
TL;DR: The results suggest that positively charged aminated gelatin could be a new absorption enhancer for nasal delivery of peptide drugs.
Abstract: This study was carried out to evaluate the potential of aminated gelatin as a nasal absorption enhancer for peptide drugs. The absorption-enhancing effect was investigated in rats using insulin and fluorescein isothiocyanate-dextran with a molecular weight of 4.4 kDa (FD-4) as model drugs. The absorption of insulin was estimated by measuring the changes in plasma glucose levels following intranasal administration, and that of FD-4 was determined by measuring its plasma concentration after dosing. The hypoglycaemic effect after intranasal administration of insulin with aminated gelatin significantly increased compared with that after intranasal administration of insulin in phosphate buffered saline, indicating that aminated gelatin effectively enhanced the nasal absorption of insulin. In contrast, neither kind of native gelatin (isoelectric point = 5.0 and 9.0) showed any absorption-enhancing effect. The pH of the formulations and the concentration of aminated gelatin were found to affect the hypoglycaemic effect. In addition, aminated gelatin at a concentration of 0.2% significantly enhanced the absorption and the efflux of FD-4 through the rat nasal mucosa. The possible perturbation of aminated gelatin to nasal mucosa was evaluated by measuring the leaching of lactate dehydrogenase (LDH) using an in-situ perfusion rat model. Aminated gelatin presented a concentration-dependent (0.1-0.4%) but relatively small effect on the LDH leaching from the rat nasal epithelial membrane. These results suggest that positively charged aminated gelatin could be a new absorption enhancer for nasal delivery of peptide drugs.
47 citations
TL;DR: This review focuses on composite scaffolds that consist of synthetic ceramics and natural polymers as drug delivery carriers for alveolar bone tissue engineering.
34 citations
TL;DR: It is concluded that the pullulan conjugation gave C60 the targetability to HepG2 cells, resulting in enhanced photodynamic tumor therapy effect.
Abstract: To design a novel cytospecific photosensitizer for photodynamic antitumor therapy, a fullerene (C60) was chemically modified with pullulan which is a water-soluble polysaccharide with a high affinity for asialoglycoprotein receptors. Ethylene diamine was introduced to the terminal aldehyde groups of pullulan by the reductive amination reaction. Pullulan was coupled to C60 through the terminal amine group. The C60 end-group conjugated with pullulan was water-soluble and generated superoxide anion upon light irradiation. The C60–pullulan conjugates significantly suppressed the in vitro growth of HepG2 hepatoma cells with asialoglycoprotein receptors, while less suppression activity was observed for HeLa cells without the receptors. The conjugates have a high binding affinity for HepG2 cells, in contrast to HeLa cells. When C60 was conjugated with polyethylene glycol (PEG) with the similar molecular weight in order to compare the in vitro cell binding and antitumor activities with the C60–pullulan conjugate,...
34 citations
TL;DR: The recent progress in gene delivery systems including viral vectors and nonviral carriers for DC-based genetically engineered vaccines and the reverse and three-dimensional transfection systems developed in DCs are described.
Abstract: Dendritic cells (DCs) are the most potent antigen-presenting cells. They play a vital role in the initiation of immune response by presenting antigens to T cells and followed by induction of T-cell response. Reported research in animal studies indicated that vaccine immunity could be a promising alternative therapy for cancer patients. However, broad clinical utility has not been achieved yet, owing to the low transfection efficiency of DCs. Therefore, it is essential to improve the transfection efficiency of DC-based vaccination in immunotherapy. In several studies, DCs were genetically engineered by tumor-associated antigens or by immune molecules such as costimulatory molecules, cytokines, and chemokines. Encouraging results have been achieved in cancer treatment using various animal models. This paper describes the recent progress in gene delivery systems including viral vectors and nonviral carriers for DC-based genetically engineered vaccines. The reverse and three-dimensional transfection systems developed in DCs are also discussed.
33 citations
TL;DR: The in vitro release study suggests that the opposite charge between the silk fibroin and basic fibroblast growth factor (bFGF) at physiological pH rendered them to form a complex, and the difference in the solvents used to produce the silk Fibroin scaffold did not affect the affinity of silk fibrain to bFGF.
Abstract: Two different solvents were used to prepare two types of silk fibroin scaffolds via the salt-leaching technique, i.e., hexafluoroisopropanol (HFIP) and water. The in vitro release study suggests that the opposite charge between the silk fibroin and basic fibroblast growth factor (bFGF) at physiological pH rendered them to form a complex, and the difference in the solvents used to produce the silk fibroin scaffold did not affect the affinity of silk fibroin to bFGF. However, a higher degradation rate of the aqueous-derived silk fibroin scaffolds provided faster in vitro release kinetics of the bFGF, as compared to the HFIP-derived scaffolds. From the in vivo studies, the use of silk fibroin scaffolds as the carrier matrix enabled the control of the in vivo release of bFGF in a sustained fashion over two weeks, while the majority of the bFGF disappeared within one day after the injection of the bFGF in soluble form. In addition, the in vivo release of bFGF from the silk fibroin scaffolds was not affected by the mode of processing due to their similar degradation behavior in vivo.
33 citations
TL;DR: The CS/PEI nanoparticle was a promising carrier for gene delivery of MSCs and Cytotoxicity of CS/ PEI complexes with plasmid DNA was significantly low, depending on the amount of PEI introduced.
Abstract: This work investigated polyethyleneimine (PEI)-introduced chitosan (CS) (CS/PEI) nanoparticles as non-viral carrier of plasmid DNA for rat mesenchymal stem cells (MSCs). The CS/PEI nanoparticles were prepared by the emulsifier-free emulsion polymerization of methyl methacrylate monomer induced by a small amount of t-butyl hydroperxide in the presence of different concentrations of PEI mixed with CS. The resulting nanoparticles were characterized by their surface properties and buffering capacity. In vitro gene transfection was also evaluated. The introduction of PEI affected the surface charge, dispersing stability and buffering capacity of the nanoparticles. The CS/PEI nanoparticles formed a complex upon mixing with a plasmid DNA of luciferase. The complex enhanced the level of gene transfection and prolonged the time period of expression for MSCs, compared with those of plasmid DNA-original CS and PEI nanoparticles. Cytotoxicity of CS/PEI complexes with plasmid DNA was significantly low, depending on the amount of PEI introduced. It is concluded that the CS/PEI nanoparticle was a promising carrier for gene delivery of MSCs.
32 citations
TL;DR: It is pointed out that an appropriate combination of 3D scaffolds and signaling molecules are required in the differentiation and maintenance of the chondrogenic phenotype during in vitro regeneration of cartilage tissue.
Abstract: Cells, signaling molecules and three-dimensional (3D) scaffolds are the major contributors to the in vitro regeneration of cartilage. This study evaluates the differentiation of mesenchymal stem cells to chondrocytes, in a 3D semi-interpenetrating polymer network (semi-IPN) scaffold that gives an appropriate niche for chondrogenic differentiation. The 3D semi-IPN scaffold poly(vinyl alcohol) and poly(caprolactone) mimics the properties of extracellular matrix of native cartilage. The chondrogenic differentiation of mesenchymal stem cells on the 3D scaffolds is carried out by supplementing signaling molecules like TGFbeta1, TGFbeta3, and BMP2 individually and in two different combinations. The results indicate that each growth factor supplement or combinations showed a different influence on cell morphology, overall distribution of cells, and secretion of cartilage specific molecules. We conclude from our results, that a combination of TGFbeta3 and BMP2 promotes better differentiation of mesenchymal stem cells to chondrocytes in our scaffold. This study hence points out that an appropriate combination of 3D scaffolds and signaling molecules are required in the differentiation and maintenance of the chondrogenic phenotype during in vitro regeneration of cartilage tissue. (c) 2010 Wiley Periodicals, Inc. J Biomed Mater Res, 2010.
TL;DR: It is concluded that pluronic is useful for the controlled release of cisplatin in a rabbit model and in animals with liver tumors, the delivery of pluronic + cisplatin produced higher tumor reduction rates than in the other groups, without apparent damage to normal liver tissue.
Abstract: The purpose of this study was to evaluate pluronic F127 for the controlled release of cisplatin in a rabbit model. Pluronic F127 becomes liquid at temperatures <25 degrees C and converts to a gelatinous state at temperatures between 25 and 60 degrees C. Six Japanese white rabbits were injected with pluronic + cisplatin (n = 3, renal group A) or saline + cisplatin (n = 3, renal group B) to measure the platinum concentration in kidneys. Another 25 rabbits with VX2 liver tumors were divided into five equal groups. They were injected with saline, saline + cisplatin, iodized oil + cisplatin, pluronic alone, or pluronic + cisplatin and labeled as liver groups A, B, C, D, and E, respectively. The antitumor effect of pluronic was then assessed. In the presence of pluronic, the platinum concentration in the kidneys of rabbits remained relatively high. In animals with liver tumors, the delivery of pluronic + cisplatin produced higher tumor reduction rates (P < 0.05) than in the other groups, without apparent damage to normal liver tissue. We conclude that pluronic is useful for the controlled release of cisplatin in a rabbit model.
TL;DR: The objective of this study is to design a fluorescent imaging agent with R-Gel, one of the recombinant polymers (RCP), for renal inflammation, and it is conceivable that the R- Gel was targeted to macrophages infiltrated into the inflammation site of kidney.
TL;DR: Although purified CD34(+) cells might be an ideal cell source, BMMNCs could be a practical and feasible cell source for bone regeneration in present clinical settings with limited cost, availability of materials, and technical issues for transplantation.
Abstract: Autologous bone marrow mononuclear cell (BMMNC) transplantation is currently an emerging clinical treatment in the orthopedic as well as cardiovascular fields. It is believed that the therapeutic effect of the BMMNCs is due to neovascularization enhanced by the CD34(+) cells contained therein, which include endothelial progenitor cells. However, isolation of the CD34(+) cell fraction for clinical application has many disadvantages such as cost and invasiveness related to cell mobilization with cytokine. To investigate whether a purification step is in fact necessary for bone regeneration, we separated BMMNCs, CD34(+), and CD34(-) cells from the same initial volume of rabbit bone marrow aspirates. We then transplanted them back into a femoral bone defect of the same rabbit together with atelocollagen gel and basic fibroblast growth factor (bFGF) and evaluated neovascularization and bone regeneration up to 8 weeks after transplantation. The greatest potential for neovascularization and bone regeneration medicated by cells from the same volume of bone marrow aspirate was found in the BMMNC group. Although purified CD34(+) cells might be an ideal cell source, BMMNCs could be a practical and feasible cell source for bone regeneration in present clinical settings with limited cost, availability of materials, and technical issues for transplantation.
TL;DR: DM-Cis may represent a magnetically-accumulated anticancer drug with hyperthermic effects and is developed for use in thermal ablation and as a chemotherapeutic drug.
Abstract: We developed a dextran-magnetite conjugated cisplatin (DM-Cis) complex for use in thermal ablation and as a chemotherapeutic drug. To produce DM-Cis we reacted Cis with 1 mL DM (56 mg/mL iron). The temperature rise of DM-Cis was measured in vitro and in vivo under a portable induction-heating (IH) device. Platinum desorption from DM-Cis over 24 hours was measured in bovine serum. In in vivo accumulation and magnet and exothermic experiments we used four rat groups. In group 1 we delivered DM-Cis intraperitoneally (ip) and placed magnets subcutaneously (sc). In group 2 we injected saline (ip) and placed magnets (sc). In group 3 we injected DM-Cis (ip) and placed a sc incision (sham). The control (group 4) received an ip injection of saline. Rectus abdominis muscle tissue was stained with hematoxylin-eosin and iron-stained tissue areas (μm(2)) were calculated. The maximum platinum concentration in DM-Cis was approximately 105.6 μg/mL. Over 24 hours, 33.48% of platinum from DM-Cis was released. There was a significant difference (P < 0.05) in the iron-stained area between group 1 and the other groups. The temperature in muscle tissue registered a maximum of 56°C after about 4 min. DM-Cis may represent a magnetically-accumulated anticancer drug with hyperthermic effects.
TL;DR: In this paper, the spin-singlet state with an excitation gap of $S=1/2\text{ }{\text{Nb}}_{4}$ tetrahedral clusters in a cluster Mott insulator was realized from the intercluster cooperative phenomenon to the singlet state.
Abstract: Muon spin relaxation $(\ensuremath{\mu}\text{SR})$ and nuclear magnetic resonance experiments revealed that the spin-singlet state with an excitation gap of $\ensuremath{\sim}200\text{ }\text{K}$ is realized from $S=1/2\text{ }{\text{Nb}}_{4}$ tetrahedral clusters in a cluster Mott insulator ${\text{GaNb}}_{4}{\text{S}}_{8}$. The intercluster cooperative phenomenon to the singlet state at ${T}_{\text{S}}=32\text{ }\text{k}$ is triggered by intracluster Jahn-Teller type structural instability developed from $\ensuremath{\sim}3{T}_{\text{S}}$. Referring to the lattice symmetry, the formation of ${\text{Nb}}_{8}$ octamer (${\text{Nb}}_{4}{\text{-Nb}}_{4}$ bond) is suggested.
TL;DR: Although GMSs and Gelpart were similar in the point of gelatin particles, the level of embolization and the degradation period were different between G MSs and gelpart.
Abstract: The object of this study was to assess the level of embolization in the embolized artery and the degradation period of these two embolic agents in the renal arteries using rabbit models. The renal artery was embolized using 5 mg of gelatin microspheres (GMSs; diameter, 35–100 μm; group 1) or 1 mg of Gelpart (diameter, 1 mm; group 2). For each group, angiographies were performed on two kidneys immediately after the embolic procedure and on days 3, 7, and 14 after embolization. This was followed by histopathological examinations of the kidneys. Follow-up angiograms on each day revealed the persistence of poorly enhanced wedge-shaped areas in the parenchymal phase in all cases. In group 1, four of six cases showed poorly enhanced small areas in the follow-up angiograms. In group 2, all cases showed poorly enhanced large areas. In the histopathological specimens, it was observed that immediately after embolization, the particles reached the interlobular arteries in group 1 and the interlobar arteries in group 2. In all cases in group 1, the particles were histologically identified even on day 14. In one case in group 2 on day 14, the particles were not identified. In conclusion, although GMSs and Gelpart were similar in the point of gelatin particles, the level of embolization and the degradation period were different between GMSs and Gelpart.
TL;DR: It is concluded that the superior properties of spermine-introduced dextran enabled the plasmid DNA to enhance the expression level to a great extent compared with other cationized dextrans.
Abstract: The objective of this study is to prepare a non-viral carrier of gene expression from the polysaccharide dextran and evaluate the effect of amine compounds introduced to dextran on the level of gene expression. Dextran with a molecular weight of 74 × 103 was cationized by the chemical introduction of different amine compounds. The cationized dextran was complexed with a plasmid DNA and the vitro gene transfection was investigated for HeLa cells. The level of gene expression depended on the amine compound introduced to dextran. The highest level was observed for the complex of spermine-introduced dextran and plasmid DNA. The highest cellular internalization and the best buffering effect were observed among every cationized dextran. Every complex did not show any cytotoxicity. It is concluded that the superior properties of spermine-introduced dextran enabled the plasmid DNA to enhance the expression level to a great extent compared with other cationized dextrans. Cationized dextran is a promising non-viral...
Journal Article•
TL;DR: In situ, tissue regeneration based on the natural self-healing potential of the body may be possible by making use of biomaterial technologies to regulate cell recruitment and their functions by efficient manipulation of in vivo local environment necessary for recruitment of host cells and their functioning.
Abstract: Tissue engineering can he classified into two strategic approaches with or without cell transplantation to induce tissue regeneration. Cell transplantation involves problems to be improved, such as low rates of cell survival and the consequently low therapeutic efficacy, and the shortage of cell source. As one trial of regenerative therapy, it is practically possible to make use of host cells present in the body. For example, efficient manipulation of in vivo local environment necessary for recruitment of host cells and their functioning will enhance the cell-induced natural healing of tissues. Peripheral blood contains several types of primitive cells with high potentials for natural healing. The in vivo recruitment of these circulating cells is being tried with biomaterials to assist and enhance the cell recruitment and retention as well as release chemoattractants. In situ, tissue regeneration based on the natural self-healing potential of the body may be possible by making use of biomaterial technologies to regulate cell recruitment and their functions.
TL;DR: The blended films were found to be more preferable materials for in vitro osteogenic differentiation of MSCs, as confirmed by alkaline phosphatase (ALP) activities, calcium contents and Von Kossa staining.
Abstract: We systematically investigated the behaviors of rat bone-marrow-derived stem cells (MSCs) on films prepared from high-molecular-mass chitosan (CH), low-molecular-mass chitooligosaccharide (COS) and their blends with gelatin (G) at various weight blending ratios. On the first day after seeding, the spreading areas of MSCs attached on the blended G/CH and G/COS films were larger than those attached on pure gelatin and COS films. Round-shaped MSCs on pure CH film were observed. The number of proliferated MSCs was also dominant in the case of blended films, at some certain blending ratios which correlated to suitably positive charge of the blended films obtained from zeta potential measurement. Among pure materials, attachment and proliferation of MSCs on COS film were comparable to those on gelatin film while CH film was toxic. The difference in toxicity of CH and COS was also confirmed by Annexin V-FITC/PI apoptosis test. After a 7-day culture under osteogenic induction, the blended films were also found to be more preferable materials for in vitro osteogenic differentiation of MSCs, as confirmed by alkaline phosphatase (ALP) activities, calcium contents and Von Kossa staining. It was proved from this study that attachment, proliferation and osteogenic differentiation of MSCs strongly depended on molecular mass of CHs and the ratio of their blends with gelatin.
Patent•
04 Mar 2010
TL;DR: In this article, the authors proposed a new hard tissue filling material having a filling property for a defective bone section, bone tissue regenerating capacity and the function of slow releasing a medicine component which accelerates it.
Abstract: PROBLEM TO BE SOLVED: To provide a new hard tissue filling material having a filling property for a defective bone section, bone tissue regenerating capacity and the function of slow releasing a medicine component which accelerates it. SOLUTION: The hard tissue filling material includes a composite comprising ceramic granules and crosslinked acid or basic gelatin hydrogel. The ceramic granules and the acid or basic gelatin hydrogel are mixed and freeze-dried and then the complex is formed by heat crosslinking reaction. Also, it is utilized as a medicine slow releasing base material. COPYRIGHT: (C)2010,JPO&INPIT
TL;DR: This work reports on a strategy for the “turn-on” detection of target biochemical (metabolic) reactions using a triple resonance NMR technique with an isotope-labeled probe and clearly reveals the importance of isotope labeling in NMR detection.
Abstract: We report on a strategy for the “turn-on” detection of target biochemical (metabolic) reactions using a triple resonance NMR technique with an isotope-labeled probe. Our NMR study clearly reveals t...
TL;DR: The Cu(2+)-coordinated PEG conjugation can modify the body distribution of protein only by simple mixing in aqueous solution and could increase the in vivo half-life period of proteins in the blood and consequently enhance the accumulation amount at the tumor site.
Abstract: The objective of this study is to introduce a new and simple conjugation method of protein with poly(ethylene glycol) (PEG) based on metal coordination. A chelating residue N,N-bis(carboxymethyl)-L-lysine (NTA) was chemically introduced into one terminal of PEG with another terminal of methoxy group (MeO-PEG). Cu2+ or Zn2+ ions were chelated into the NTA residue of MeO-PEG-NTA prepared. Chromatographic experiments revealed that transferrin (Tf) was conjugated to the MeO-PEG-NTA based on Cu2+ ions coordination. The amount of PEG conjugated increased with an increase in that added. Fluorescently labeled Tf was conjugated by the MeO-PEG-NTA with Cu2+ or Zn2+ coordination and injected intravenously into tumor-bearing mice. The Tf conjugated with the MeO-PEG-NTA based on Cu2+ coordination was accumulated in the tumor site to a significantly great extent compared with the free Tf and Tf conjugated with the Zn2+ coordinated MeO-PEG-NTA. A body distribution assay with radiolabeled Tf demonstrated that PEG conjugation with Cu2+ coordination enabled Tf to prolong the blood circulation and enhance the tumor accumulation. When interferon (IFN) was conjugated with the Cu(2+)-coordinated MeO-PEG-NTA and subcutaneously injected into tumor-bearing mice, the in vivo tumor growth was significantly suppressed compared with the injection of free IFN and IFN conjugated by Zn(2+)-coordinated MeO-PEG-NTA. It is concluded that the Cu(2+)-coordinated PEG conjugation can modify the body distribution of protein only by simple mixing in aqueous solution. The PEG conjugation with metal coordination could increase the in vivo half-life period of proteins in the blood, and consequently enhance the accumulation amount at the tumor site.
TL;DR: A method to improve surface activity of gelatin by modifying it into an amphiphilic molecule via conjugating with cholesterol using N,N’-Disuccinimidyl carbonate is proposed.
Abstract: Gelatin, a hydrophilic protein derived from collagen, has been widely used in drug delivery system because of its biocompatibility and biodegradability. However, its high water solubility limited its interaction with hydrophilic drugs. The current works propose a method to improve surface activity of gelatin by modifying it into an amphiphilic molecule via conjugating with cholesterol. High contents of cholesterol were conjugated to amino groups (-NH2) of gelatin using N,N’-Disuccinimidyl carbonate. Cholesterol contents were varied from 100% by mole of free -NH2 group in gelatin. The reduction of free -NH2 groups on gelatin determined by 2,4,6-trinitrobenzenesulfonic acid (TNBS) decreased with the increases of cholesterol used in the conjugation. The percentage of reduction of -NH2 content was 74.63 by mole respectively. Hydrophilicity/hydrophobicity changes were evaluated from water and ethylene glycol contact angles. The conjugated-gelatin were aggregated to form micelles at a critical micelle concentration (CMC) of 8 mg/ml in DI water (pH 5), determined by surface tension testing. Average size of the micelles were in range of 459.05±54.59 nm. The micelles were tested for curcumin entrapment for a cancer research.
01 Apr 2010
TL;DR: In this article, the magnetic ground state of GaNb4S8 was investigated by means of the zero-field (ZF) and the longitudinal field (LF)?SR techniques.
Abstract: GaNb4S8 is a S = 1/2 Nb4-cluster magnet exhibiting a structural phase transition at Ts = 32 K. We have investigated the magnetic ground state of the compound by means of the zero-field (ZF) and the longitudinal-field (LF) ?SR techniques. In the ZF-?SR spectra, no muon spin precession was observed below Ts, revealing an absence of magnetic long-range orders. Instead, an stretched exponential relaxation was observed, which remains under the LF up to 3950 G. The field dependence of the relaxation rate obeys the Redfield's equation, indicating that a dynamic component of electronic spin fluctuations is dominant below Ts. These ?SR results can be understand as sporadic dynamics of spin fluctuations in a spin singlet sea and support the spin singlet state of GaNb4S8 due to the formation of Nb8 octamer from two Nb4 tetramers.
TL;DR: All journals reported a significantly higher amount of institutional ethical approval for animal research as compared to human research (P<0.05).
Abstract: Results: Of the 1759 articles reviewed, 939 (53%) were included (instructional course lectures, discussions, and correspondence were excluded). Research Ethics Board approval for human research was not reported in 687 (84%) articles: PRS (n=317, 81%), Annals (n= 160, 87%), JPRAS (n=182, 88%), and Aesthetic (n=30, 79%). 116 (7%) articles included animal research. Animal Ethics was not reported in 54 (45%) of these articles: PRS (n=35, 55%), Annals (n= 9, 29%), JPRAS (n=10, 43%), and Aesthetic (n=0, 0%). All journals reported a significantly higher amount of institutional ethical approval for animal research as compared to human research (P<0.05). IC was not reported in 726 (89%): PRS (n=346, 88%), Annals (n=159, 88%), JPRAS (n=185, 89%), and Aesthetic (n=36, 93%).
23 Aug 2010
TL;DR: This study investigated regulatory role of bFGF for detrusor overactivity and involvement of connexin 43, a gap junction protein.
Abstract: Hypothesis / aims of study Detrusor overactivity is a highly prevalent clinical condition in bladder outlet obstruction (BOO) and result from neurogenic changes in detrusor innervation or myogenic changes in detrusor excitability [1]. Increased coupling of bladder smooth muscle cells (BSMC) through gap junctions has been hypothesized as a mechanism for myogenic bladder overactivity in BOO [2], although little is known about the regulatory system underlying such changes. Meanwhile, our previous study showed that bFGF up-regulation in BOO induced alteration in collagen production and BSMC proliferation [3]. Hence, we investigated regulatory role of bFGF for detrusor overactivity and involvement of connexin 43, a gap junction protein.
01 Jan 2010
TL;DR: In this article, the high-field magnetization of a quasi-one dimensional S = 1/2 chain compound Sb2VO5 was measured at 4.2 K, indicating the excitation from a spin singlet ground state to a triplet state.
Abstract: We have measured the high-field magnetization of a quasi-one dimensional S=1/2 chain compound Sb2VO5, which was proposed as a new candidate of the inorganic spin-Peierls (SP) system. The magnetization measured at 4.2 K exhibits a clear inflection at around 23 T, indicating obviously the excitation from a spin singlet ground state to a triplet state. Absence of anomalies in specific heat and X-ray diffraction points to no SP transition, and the analysis of the susceptibility suggests that this compound is an alternating spin chain system.