Nonmagnetic Ground State in RuO_{2} Revealed by Muon Spin Rotation.

The magnetic ground state of single crystalline RuO_{2} was investigated by the muon spin rotation and relaxation (µSR) experiment. The spin precession signal due to the spontaneous internal magnetic field B_{loc}, which is expected in the magnetically ordered phase, was not observed in the temperature range 5-400 K. Muon sites were evaluated by first-principles calculations using dilute hydrogen simulating muon as pseudohydrogen, and B_{loc} was simulated for the antiferromagnetic structures with a Ru magnetic moment |m_{Ru}|≈0.05µ_{B} suggested from diffraction experiments. As a result, the possibility was ruled out that muons are localized at sites where B_{loc} accidentally cancels. Conversely, assuming that the slow relaxation observed in µSR spectra was part of the precession signal, the upper limit for the magnitude of |m_{Ru}| was estimated to be 4.8(2)×10^{-4}µ_{B}, which is significantly less than 0.05µ_{B}. These results indicate that the antiferromagnetic order, as reported, is unlikely to exist in the bulk crystal.

Factors affecting psychological stress in children who cooperate with dental treatment: a pilot study.

AIM: Few studies have examined psychological stress and personal anxiety in children exhibiting cooperative behaviour during dental treatment. We assessed psychological stress and personal anxiety during dental treatment in cooperative children, and investigated the influence of various factors. MATERIALS AND METHODS: We measured pre- and post-treatment salivary alpha amylase (sAA) levels of 28 children aged 8-13 years and their parents. Children completed the State-Trait Anxiety Inventory for Children (STAIC); their parents completed the STAI. The IA group included children whose sAA levels increased >10%, whereas the DA group included children whose sAA levels decreased >10%. We used regression models to calculate the power of variables to predict children's psychological stress. RESULTS: The mean anxiety trait score in the IA group was significantly higher than in the DA group (t-test, P = 0.021). For children with higher STAIC-Trait scores, the OR for increasing sAA was 1.16 (95% CI [1.02-1.31]). Parental or treatment factors did not significantly contribute to incremental sAA levels in children. CONCLUSION: Well-behaved children with high anxiety traits may experience high stress levels during dental treatment; however, parental and dental treatment factors may not affect psychological stress in these children.

Risk factors for Clostridium difficile-associated diarrhea and the effectiveness of prophylactic probiotic therapy.

Measures for prevention of Clostridium difficile-associated diarrhea, a common nosocomial infection, in hospital settings are urgently needed. This study was conducted to identify the risk factors contributing to C. difficile-associated diarrhea and to evaluate the clinical benefit of probiotics in its prevention. The study included 2716 patients at least 20 years old who received an injected antibiotic at any time between February 2010 and February 2011; a total of 2687 patients (98.9%) were assigned to the non-C. difficile-associated diarrhea group, and 29 patients (1.1%) were assigned to the C. difficile-associated diarrhea group. Univariate analysis revealed a significant difference between the two groups for the following factors: antibiotic therapy for > or = 8 days; enteral nutrition; intravenous hyperalimentation; fasting; proton pump inhibitor use; H2 blocker use; and serum albumin < or = 2.9g/dL (p<0.05). Multivariate logistic regression analysis revealed a significant difference between the two groups for several factors. Antibiotic therapy for > or = 8 days, intravenous hyperalimentation, proton pump inhibitor use, and H2 blocker use were therefore shown to be risk factors for C. difficile-associated diarrhea. Prophylactic probiotic therapy was not shown to suppress the occurrence of C. difficile-associated diarrhea.

Insular superconductivity in a Co-doped iron pnictide CaFe1-xCoxAsF.

The presence of a macroscopic phase separation between the superconducting and magnetic phases in CaFe1-xCoxAsF is demonstrated by muon spin rotation measurements conducted across their phase boundaries (x=0.05-0.15). The magnetic phase tends to retain the high transition temperature (Tm>Tc), while Co doping induces strong randomness. The volumetric fraction of the superconducting phase is nearly proportional to the Co content x with a constant superfluid density. These observations suggest the formation of superconducting "islands" (or domains) associated with Co ions in the Fe2As2 layers, indicating a very short coherence length.

Hydrogen bonding in sodium alanate: a muon spin rotation study.

We have detected the occurrence of hydrogen bonding involving an interstitial positive muon situated between hydrogen atoms of two independent alanate anions in sodium alanate (NaAlH4). Ti doping, which is known to dramatically improve the hydrogen cycling performance of NaAlH4, reduces the kinetic barrier of the transition of the muon from the muon-dialanate state to a mobile interstitial state. This observation strongly suggests that hydrogen bonding is the primary bottleneck for hydrogen release or uptake in sodium alanate, which might be common to other complex hydrides.

Coexistence of long-range order and spin fluctuation in geometrically frustrated clinoatacamite Cu2Cl(OH)3.

Muon spin rotation experiments are carried out on clinoatacamite, Cu2Cl(OH)3, which is a new geometrically frustrated system featuring a three-dimensional network of corner-sharing tetrahedral 3d Cu2+ spins. A long-range antiferromagnetic order occurs below 18.1 K with a surprisingly small entropy release of about 0.05Rln2/Cu. Below 6.5 K, the static long-range order transforms abruptly into a metastable state with nearly complete depolarization of muon spins which suggests strong fluctuation. The system then enters a state in which partial long-range order and spin fluctuation coexist down to the lowest experimentally attainable temperature of 20 mK. This work presents a novel system for studying geometric frustration.

Staggered magnetism in LiV(2)O(4) at low temperatures probed by means of the muon Knight shift.

We report on measurement of the muon Knight shift in single crystals of LiV(2)O(4). Contrary to what is anticipated for the heavy fermion state based on the Kondo mechanism, the presence of inhomogeneous local magnetic moments is demonstrated by the broad distribution of the Knight shift at temperatures well below the presumed 'Kondo temperature' ([Formula: see text] K). Moreover, a significant fraction ([Formula: see text]) of the specimen gives rise to a second component which is virtually non-magnetic. These observations strongly suggest that the anomalous properties of LiV(2)O(4) originate from frustration of local magnetic moments.

Time-reversal symmetry-breaking superconductivity in heavy-fermion PrOs4Sb12 detected by muon-spin relaxation.

We report on muon-spin relaxation measurements of the 4f(2)-based heavy-fermion superconductor filled-skutterudite Pr(Os4Sb12. The results reveal the spontaneous appearance of static internal magnetic fields below the superconducting transition temperature, providing unambiguous evidence for the breaking of time-reversal symmetry in the superconducting state. A discussion is made on which of the spin or orbital component of Cooper pairs carries a nonzero momentum.

Bullfrog ghrelin is modified by n-octanoic acid at its third threonine residue.

We have identified the amphibian ghrelin from the stomach of the bullfrog. We also examined growth hormone (GH)-releasing activity of this novel peptide in both the rat and bullfrog. The three forms of ghrelin identified, each comprised of 27 or 28 amino acids, possessed 29% sequence identity to the mammalian ghrelins. A unique threonine at amino acid position 3 (Thr(3)) in bullfrog ghrelin differs from the serine present in the mammalian ghrelins; this Thr(3) is acylated by either n-octanoic or n-decanoic acid. The frog ghrelin-28 has a complete structure of GLT (O-n-octanoyl)FLSPADMQKIAERQSQNKLRHGNM; the structure of frog ghrelin-27 was determined to be GLT(O-n-octanoyl)FLSPADMQKIAERQSQNKLRHGN; frog ghelin-27-C10 possessed a structure of GLT(O-n-decanoyl)FLSPADMQKIAERQSQNKLRHGN. Northern blot analysis demonstrated that ghrelin mRNA is predominantly expressed in the stomach. Low levels of gene expression were observed in the heart, lung, small intestine, gall bladder, pancreas, and testes, as revealed by reverse transcription polymerase chain reaction analysis. Bullfrog ghrelin stimulated the secretion of both GH and prolactin in dispersed bullfrog pituitary cells with potency 2-3 orders of magnitude greater than that of rat ghrelin. Bullfrog ghrelin, however, was only minimally effective in elevating plasma GH levels following intravenous injection into rats. These results indicate that although the regulatory mechanism of ghrelin to induce GH secretion is evolutionary conserved, the structural changes in the different ghrelins result in species-specific receptor binding.

Cosecretion of prolactin and growth hormone by dispersed pituitary cells of the adult bullfrog, Rana catesbeiana.

The coexistence of prolactin (PRL) and growth hormone (GH) was previously demonstrated in newly hatched bullfrog (Rana catesbeiana) tadpoles, whereas in adult bullfrogs, there were no cells containing both PRL and GH. However, a cell blot assay with enzymatically dispersed adult pituitary cells demonstrated the existence of cells secreting both PRL and GH. The number of cells secreting both PRL and GH was reduced by a protein synthesis inhibitor, cycloheximide, but not by an RNA synthesis inhibitor, actinomycin D. In situ hybridization and immunostaining of intact pituitary glands revealed the existence of GH mRNA in some of the PRL-immunoreactive cells and of PRL mRNA in some of the GH-immunoreactive cells. We propose that dispersion of the pituitary cells triggered the translation of GH mRNA in the PRL cells and/or of PRL mRNA in the GH cells.

Protective involvement of nitric oxide in the liver injury induced by delayed-type hypersensitivity to picryl chloride.

OBJECTIVE AND DESIGN: To investigate the role of nitric oxide (NO) in the liver injury induced by delayed-type hypersensitivity to picryl chloride (PCl-DTH). MATERIALS AND METHODS: Liver injury was induced in mice by PCl-DTH. NO production was examined using the Griess reagent. Isolated hepatocytes (HC) and nonparenchymal cells (NPC) were used. RESULTS: NO production in both serum and liver tissue reached a peak at 36 h after the elicitation of liver injury. The in vitro NO production was only observed by NPC or HC isolated at 24 h after the injury. Co-stimulation of IFN-gamma and TNF-alpha significantly triggered the HC and NPC isolated at 0 h to produce NO. As NO synthase inhibitors, Nomega-Nitro-L-Arginine exacerbated the liver injury in mice and NG-Monomethyl-L-Arginine enhanced the hepatotoxicity of IFN-gamma and TNF-alpha in vitro. In contrast, NO producer, S-nitroso-N-acetylpenicillamine dose-dependently inhibited the hepatotoxicity of NPC. CONCLUSIONS: NO may be produced by HC and NPC under the co-stimulation of IFN-gamma and TNF-alpha, and may play an important role for alleviating the liver injury.

Inhibitory effect of a novel quinolinone derivative, TA-270, on asthmatic inflammatory responses in sensitized guinea pigs.

TA-270 (4-hydroxy-1-methyl-3-octyloxy-7-sinapinoylamino-2(1H)- quinolinone), a novel quinolinone derivative, was designed as an antioxidant to scavenge reactive oxygen species. Here, we investigated the effects of TA-270, in comparison with several antiasthmatic drugs, on asthmatic responses as induced by ovalbumin in sensitized guinea pigs. When orally administered 1 h before and 3 h after the antigen challenge, TA-270 at 10 mg/kg and higher doses significantly inhibited both immediate and late responses in airway resistance induced by the antigen. The inhibitory effects were comparable to or superior, at least under the present experimental conditions, to those of several clinically used antiasthmatic drugs. Furthermore, TA-270, in a dose-dependent manner, reduced accumulation of pulmonary inflammatory cells, especially eosinophils, and significantly reversed the airway hyperresponsiveness to acetylcholine 24 h after the antigen challenge. These results suggest that TA-270 may be of therapeutic use for bronchial asthma.

Occurrence of immunoreactive Activin/Inhibin beta(B) in thyrotropes and gonadotropes in the bullfrog pituitary: possible Paracrine/Autocrine effects of activin B on gonadotropin secretion.

Occurrence of immunoreactive activin/inhibin beta(B) in the bullfrog (Rana catesbeiana) pituitary was investigated immunocytochemically by use of antibody against Xenopus activin/inhibin beta(B) subunit. Thyrotropes were demonstrated to contain activin/inhibin beta(B)-immunoreactive substances. Moreover, immunoelectron microscopy revealed that in the secretory granules of thyrotropes and, to a lesser extent, in those of gonadotropes, activin/inhibin beta(B)-immunoreactive substances were present. Based on this observation, we investigated the effect of activin B on the release of gonadotropins from dispersed anterior pituitary cells of the bullfrog. Activin B stimulated the release of not only follicle-stimulating hormone (FSH) but also luteinizing hormone (LH) dose dependently. Under the culture conditions used in this experiment, inhibin B, as well as follistatin, did not affect the basal levels of LH and FSH, but they suppressed the activin-induced release of these hormones. This is the first study on the effect of activin on pituitary hormone secretion in lower tetrapods.

Astilbin selectively induces dysfunction of liver-infiltrating cells--novel protection from liver damage.

The present study aimed to examine the effect of astilbin, a flavanoid, on liver injury. When administered during the effector but not induction phase, astilbin significantly decreased the liver injury induced by delayed-type hypersensitivity to picryl chloride in mice. The pretreatment of nonparenchymal cells but not hepatocytes with astilbin in vitro caused a concentration- and time-dependent inhibition against the damage. Nonparenchymal cells isolated from astilbin-administered mice also showed a significant incompetence of hepatotoxicity, correlated with the inhibition of serum transaminase elevation. However, astilbin did not protect from CCl4-induced liver damage. Furthermore, the flavanoid markedly promoted the apoptosis of nonparenchymal cells from liver-injured mice, whereas did not influence those from naive mice. These results suggest that astilbin provides improvement against liver injury through a selective dysfunction of liver-infiltrating cells rather than by protecting the hepatocyte membrane. Such characteristics will be of significance to pave a new way for treating immunologically related liver diseases and for developing new drugs.

Role of Th1 and Th2 cytokines in regulating the liver injury induced by delayed-type hypersensitivity to picryl chloride.

AIMS/BACKGROUND: We have previously reported that a new model of liver injury induced in mice by delayed-type hypersensitivity (DTH) to picryl chloride (PCl) mimicks the pathogenesis of human hepatitis. This liver injury is mediated by CD4+ T cells. The interaction between lymphocyte function associated antigen 1 (LFA-1) and intercellular adhesion molecule 1 (ICAM-1) is an essential process for hepatocyte (HC) damage. The present study was undertaken to reveal the role of Th1 and Th2-like cytokines in regulating the liver injury. METHODS: The kinetics of cytokine production were examined by ELISA and RT-PCR after the elicitation of liver injury for both serum protein and liver mRNA expression, respectively. A co-culture assay between liver nonparenchymal cells (NPC) and HC was conducted to evaluate the cytokine regulation on the cell-cell interaction. Expression of LFA-1 on NPC and ICAM-1 on HC were examined by FACScan and ELISA, respectively. RESULTS: Serum IL-2 and IFN-gamma showed a peak production at 6 and 12 h, while IL-5 and IL-4 reached their maximum levels at 18 and 24 h after induction of liver injury, respectively. Liver mRNA expression of IFN-gamma and IL-4 had a similar time course to their corresponding products. Both recombinant murine IFN-gamma and IL-2 triggered the hepatotoxicity of NPC or spleen cells at 0 h. In this case, an increased expression of both LFA-1 on NPC and ICAM-1 on HC was also observed. In contrast, IL-4 and IL-5 completely abolished the hepatotoxicity of NPC at 12 h without influencing the adhesion molecules. CONCLUSION: Th1 and Th2 may be involved in regulating liver injury. Th1/Th2 balance may critically contribute to the production of the liver injury or recovery from it.

Antiallergic action of betotastine besilate (TAU-284) in animal models: A comparison with ketotifen.

The effects of betotastine besilate (betotastine: TAU-284), a novel antiallergic drug, on homologous passive cutaneous anaphylaxis (PCA), mediator-induced cutaneous reaction, antigen-induced asthmatic responses and platelet-activating factor (PAF)-induced airway eosinophilia in several animal models, were compared to ketotifen. Betotastine (0.1 mg/kg, p.o.) and ketotifen (1 mg/kg, p.o.) inhibited both rat PCA and histamine-induced cutaneous reaction, whereas they showed little effect on serotonin-induced cutaneous reaction. Betotastine (0.3 mg/kg, p.o.) and ketotifen (1 mg/kg, p.o. ) significantly inhibited antigen-induced bronchoconstriction in guinea pigs which had been passively sensitized with guinea pig IgE antibody. In actively sensitized guinea pigs, the immediate and late phase increase in airway resistance (Rrs) were observed within 5 min and between 4 and 7 h after the aeroantigen challenge. Betotastine (1 mg/kg, p.o.) inhibited both responses. Ketotifen (1 mg/kg, p.o.) inhibited the immediate phase response, but did not affect the late phase response. Exposure of guinea pigs to aerosolized PAF increased the number of eosinophils in bronchoalveolar lavage fluid 24 h after the stimulation. Betotastine (3-10 mg/kg, p.o.) dose-dependently inhibited PAF-induced accumulation of eosinophils in the bronchoalveolar cavity. In contrast, cetirizine (10 mg/kg, p.o.) showed a tendency to inhibit eosinophil accumulation, and ketotifen (10 mg/kg, p.o.) and terfenadine (10 mg/kg, p.o.) did not have any affect. These results indicate that betotastine could be useful in the treatment of allergic disease such as bronchial asthma.

Synthesis and antiallergic activity of dimethyl-2-(phenylcarbamoyl)ethylsulfonium p-toluenesulfonate derivatives.

The derivatives of dimethyl-2-(phenylcarbamoyl)ethylsulfonium p-toluenesulfonates were synthesized and evaluated for antiallergic activity. The 2,3-dihydroxyethoxy group was introduced to the phenyl ring from the standpoint of lipophilicity and electronic effects of substituent. The IgE-induced rat passive cutaneous anaphylaxis (PCA) was inhibited by oral administration of several substituted 2-[(4-propoxyphenyl)carbamoyl]ethyldimethylsulfonium p-toluenesulfonate derivatives. Among them (+/-)-2-[N-[4-(3-ethoxy-2-hydroxypropoxy)phenyl]carbamoyl]ethyldimeth ylsulfonium p-toluenesulfonate (1a, IPD-1151T) was found to possess considerable activity in the PCA test, and it was launched as Suplatast tosilate in Japan.

The effects of TYB-2285 and its metabolites on lymphocyte responses in vitro.

1. We examined the effects of TYB-2285 and its metabolites (TC-286 and TC-326) on antigen-induced lymphocyte proliferation, allogeneic mixed lymphocyte reaction (MLR) and mitogen-induced lymphocyte proliferation. 2. Splenic lymphocytes from C57BL/6 strain mice sensitized with human serum albumin were cultured with the antigen in the presence of TYB-2285 or its metabolites (10(-7)-10(-4) M). The lymphocyte proliferation enhanced by antigen was inhibited by TYB-2285 and its metabolites in a dose-dependent manner. 3. Splenic lymphocytes collected from C57BL/6 and Balb/C strain mice were cocultured in the presence of TYB-2285 and its metabolites (10(-7)-10(-4) M). Allogeneic MLR was inhibited by TYB-2285 and its metabolites in a dose-dependent manner. 4. Splenic lymphocytes from C47BL/6 strain mice were cultured with concanavalin A (Con A) in the presence of TYB-2285 and its metabolites (10(-7)-10(-4) M). TYB-2285 and its metabolites did not affect Con A-induced lymphocyte proliferation. Cyclosporin A showed an inhibitory effect on Con A-induced lymphocyte proliferation that was as strong as the inhibitory effect on antigen-induced lymphocyte proliferation and allogeneic MLR at a lower concentration.

Irreversible cytotoxic effect of a novel lowly immunosuppressive antitumor fluorouridine derivative, UK-21.

Previously, we reported that the 5-fluorouridine derivative, 2',3',5'-tris-O-[N(2-n-propyl-n-pentanoylglycyl]-5-fluorouridine (UK-21), is a newly synthesized lowly immunosuppressive and potent antitumor drug in comparison with other fluorouridine derivatives such as 5-fluorouracil (5-FU), 5-fluorouridine (5-FUR) and 5-fluorodeoxyuridine (5-FUDR). In order to elucidate the molecular mechanism of antitumor activity of UK-21, we compared the effect of the four drugs on cell proliferation, cell cycle progression and macromolecular syntheses. When KB cells were subjected to a colony-forming inhibition assay designed to expose the cells to the drugs for 4-96 h and wash out, UK-21 and 5-FUR inhibited the colony formation at concentrations ranging from 0.01 to 0.1 microM, whereas 1-100 microM was needed for the cytotoxicity of 5-FU and 5-FUDR. By exposure for 24-48 h, all these drugs inhibited cell growth and caused accumulation of the cells in S or G2 phase at almost the same concentrations of 0.32-8 microM. These results suggest that the cytotoxic effects of UK-21 and 5-FUR are irreversible, while those of 5-FU and 5-FUDR are reversible. To confirm this, KB cells were treated with UK-21 and/or 5-FU for 1 h, and continued to be cultured for 1-7 days, resulting in the inhibition of the cell growth by UK-21 in a dose-dependent manner at concentrations of 10-100 microM, but not by 5-FU even at 100 microM. UK-21, 5-FUR and 5-FU showed a linear relationship between exposure time and IC50 in the colony formation assay with a slope of almost -1, but 5-FUDR did not, suggesting that UK-21, 5-FUR and 5-FU are cell cycle non-specific inhibitors, while 5-FUDR is a cell cycle-specific inhibitor. UK-21 and 5-FUR, but not 5-FU and 5-FUDR inhibited the incorporation of [3H]uridine into the acid insoluble fraction, while UK-21 and 5-FUDR, but not 5-FUR and 5-FU inhibited the incorporation of [3H]thymidine. These results suggest that irreversible cytotoxic effects of UK-21 like 5-FUR are exerted through inhibition of RNA synthesis.

Effect of TYB-2285 on antigen-induced accumulation of eosinophils into the peritoneal cavity of rats sensitized with Ascaris suum extract.

1. The present study was carried out to investigate the effect of 3,5-bis-(acetoxyacetylamino)-4-chloro-benzonitrile (TYB-2285) on the accumulation of eosinophils in the peritoneal cavity of Wistar rats sensitized with Ascaris suum extract (Asc). 2. Rats were sensitized by IP injection of Asc on day 0 and were challenged by IP injection of Asc on day 7. Antigen challenge caused a specific, delayed infiltration of eosinophils into the peritoneal cavity that was inhibited by PO administration of TYB-2285, but not ketotifen fumarate, in a dose-dependent manner (3-30 mg/kg). 3. TYB-2285 inhibited the infiltration of eosinophils when during the induction phase, but not during the effector phase. The inhibitory effect of TYB-2285 when during the induction phase was stronger than any other antiallergic drugs, such as tranilast, azelastine, ibudilast, repirinast, tazanolast, oxatomide, or pemirolast. 4. Transfer of lymphocytes, but not serum, from sensitized rats to intact rats provoked a remarkable infiltration of eosinophils after the antigen challenge. In the experiment of adoptive transfer in rats, TYB-2285 was effective when given to donor rats. 5. These results demonstrate that TYB-2285 inhibits the accumulation of eosinophils presumably by inhibiting antigen recognition.