High-frequency spin torque oscillation in orthogonal magnetization disks with strong biquadratic magnetic coupling.

In this study, we numerically investigate the spin transfer torque oscillation (STO) in a magnetic orthogonal configuration by introducing a strong biquadratic magnetic coupling. The orthogonal configuration consists of top and bottom layers with in-plane and perpendicular magnetic anisotropy sandwiching a nonmagnetic spacer. The advantage of an orthogonal configuration is the high efficiency of spin transfer torque leading a high STO frequency; however, maintaining the STO in a wide range of electric current is challenging. By introducing biquadratic magnetic coupling into the orthogonal structure of FePt/spacer/Co90Fe10, Ni80Fe20 or Ni, we were able to expand the electric current region in which the stable STO is realized, resulting in a relatively high STO frequency. For example, approximately 50 GHz can be achieved in an Ni layer at a current density of 5.5 × 107 A/cm2. In addition, we investigated two types of initial magnetic state: out-of-plane and in-plane magnetic saturation; this leads to a vortex and an in-plane magnetic domain structure after relaxation, respectively. The transient time before the stable STO was reduced to between 0.5 and 1.8 ns by changing the initial state from out-of-plane to in-plane.

N-methylnicotinamide is an endogenous probe for evaluation of drug-drug interactions involving multidrug and toxin extrusions (MATE1 and MATE2-K).

Multidrug and toxin extrusion 1 (MATE1) and MATE2-K are H(+)/organic cation exchangers mediating the efflux of cationic drugs into the urine. N-methylnicotinamide (NMN) was found to be an endogenous substrate of MATE1 (Michaelis constant (K(m)) 301 ± 18 µmol/l) and MATE2-K (K(m) 422 ± 63 µmol/l) as well as a basolateral influx transporter, organic cation transporter 2 (K(m) 318 ± 29 µmol/l). A potent MATE inhibitor, pyrimethamine, competitively inhibited the uptake by MATE1 and MATE2-K with inhibition constant (K(i)) values of 83 ± 15 and 56 ± 11 nmol/l, respectively. The uptake of NMN by human kidney brush border membrane vesicles with a H(+) gradient was saturable (K(m) 360 ± 55 µmol/l) and completely inhibited by pyrimethamine. The renal clearance of endogenous NMN was 403 ± 61 in healthy male subjects, and it was significantly decreased to 119 ± 16 ml/min/kg by an oral dose of pyrimethamine (50 mg). These results support the utility of NMN as an endogenous in vivo probe for investigating MATE1 and MATE2-K in humans.

Effects of a MATE protein inhibitor, pyrimethamine, on the renal elimination of metformin at oral microdose and at therapeutic dose in healthy subjects.

A microdose study of metformin was conducted to investigate the predictability of drug-drug interactions at the therapeutic dose (ThD). Healthy subjects received a microdose (100 µg) or ThD (250 mg) of metformin orally, with or without a potent and competitive multidrug and toxin extrusion (MATE) inhibitor, pyrimethamine (50 mg, p.o.), in a crossover fashion. Pyrimethamine significantly reduced the renal clearance of metformin by 23 and 35% at the microdose and ThD, respectively. At ThD, but not at microdose, it caused significant increases in the maximum concentration (C(max)) and area under the plasma concentration-time curve (AUC) of metformin (142 and 139% of control values, respectively). Human canalicular membrane vesicles showed pyrimethamine-inhibitable metformin uptake. Pyrimethamine did not affect plasma lactate/pyruvate after ThD of metformin but significantly reduced the renal clearance of creatinine, thereby causing elevation of plasma creatinine level. This microdose study quantitatively predicted a drug-drug interaction involving the renal clearance of metformin at ThD by pyrimethamine. Pyrimethamine is a useful in vivo inhibitor of MATE proteins.

Prediction of fluoroquinolone-induced elevation in serum creatinine levels: a case of drug-endogenous substance interaction involving the inhibition of renal secretion.

The aim of this study was to examine the mechanism underlying the elevation in serum creatinine levels caused by a novel des-fluoro(6)-quinolone antibacterial agent, DX-619, in healthy subjects. hOCT2 showed a prominent uptake of creatinine (K(m) = 56.4 mmol/l) among renal organic ion transporters. DX-619 is a potent inhibitor of hOCT2 (K(i) = 0.94 micromol/l), hMATE1 (0.82 µmol/l), and hMATE2-K (0.10 micromol/l). The pharmacokinetic model involving the inhibition of hOCT2 (model 1), hOCT2, and MATE1 or MATE2-K (model 2) could predict the elevation in serum creatinine levels in individual subjects receiving DX-619. This assumes that a significant contribution of tubular secretion (59, 38, and 31%) and reabsorption ranged from 3-50, 4-30, and 5-21% in model 1, -2a (hOCT2/hMATE1), and -2b (hOCT2/hMATE2-K), respectively, for creatinine. In conclusion, DX-619, at its therapeutic dose, is able to inhibit hOCT2, hMATE1, and hMATE2-K, leading to a significant inhibition of tubular secretion of creatinine and consequently to elevation of serum creatinine levels.

Enhancement of magnetoresistance by hydrogen ion treatment for current-perpendicular-to-plane giant magnetoresistive films with a current-confined-path nano-oxide layer.

We have enhanced magnetoresistance (MR) for current-perpendicular-to-plane giant-magnetoresistive (CPP-GMR) films with a current-confined-path nano-oxide layer (CCP-NOL). In order to realize higher purity in Cu for CCPs, hydrogen ion treatment (HIT) was applied as the CuO(x) reduction process. By applying the HIT process, an MR ratio was increased to 27.4% even in the case of using conventional FeCo magnetic layer, from 13.0% for a reference without the HIT process. Atom probe tomography data confirmed oxygen reduction by the HIT process in the CCP-NOL. The relationship between oxygen counts and MR ratio indicates that further oxygen reduction would realize an MR ratio greater than 50%.

Biochemical characteristics and inhibitor selectivity of mouse indoleamine 2,3-dioxygenase-2.

The first step in the kynurenine pathway of tryptophan catabolism is the cleavage of the 2,3-double bond of the indole ring of tryptophan. In mammals, this reaction is performed independently by indoleamine 2,3-dioxygenase-1 (IDO1), tryptophan 2,3-dioxygenase (TDO) and the recently discovered indoleamine 2,3-dioxygenase-2 (IDO2). Here we describe characteristics of a purified recombinant mouse IDO2 enzyme, including its pH stability, thermal stability and structural features. An improved assay system for future studies of recombinant/isolated IDO2 has been developed using cytochrome b (5) as an electron donor. This, the first description of the interaction between IDO2 and cytochrome b (5), provides further evidence of the presence of a physiological electron carrier necessary for activity of enzymes in the "IDO family". Using this assay, the kinetic activity and substrate range of IDO2 were shown to be different to those of IDO1. 1-Methyl-D-tryptophan, a current lead IDO inhibitor used in clinical trials, was a poor inhibitor of both IDO1 and IDO2 activity. This suggests that its immunosuppressive effect may be independent of pharmacological inhibition of IDO enzymes, in the mouse at least. The different biochemical characteristics of the mouse IDO proteins suggest that they have evolved to have distinct biological roles.

Regulatory mechanisms of C4b-binding protein (C4BP)alpha and beta expression in rat hepatocytes by lipopolysaccharide and interleukin-6.

BACKGROUND: C4b-binding protein (C4BP), a multimeric protein structurally composed of alpha chains (C4BPalpha) and a beta chain (C4BPbeta), regulates the anticoagulant activity of protein S (PS). Patients with sepsis have increased levels of plasma C4BP, which appears to be induced by interleukin (IL)-6. However, it is not fully understood how lipopolysaccharide (LPS) and IL-6 affect the plasma C4BP antigen level and C4BPalpha and C4BPbeta expression in hepatocytes. OBJECTIVES: To assess the effect of LPS and IL-6 on plasma C4BP, PS-C4BP complex levels, PS activity, and C4BP expression by rat liver in vivo and on C4BP expression by isolated rat hepatocytes in vitro. RESULTS: Plasma C4BP antigen level transiently decreased from 2 to 12 h after LPS (2 mg kg(-1)) injection, and then it abruptly increased up to 24 h after LPS injection. Plasma C4BP antigen level increased until 8 h after IL-6 (10 microg kg(-1)) injection, and then gradually decreased up to 24 h after IL-6 injection. LPS significantly decreased the protein and mRNA expression of both C4BPalpha and C4BPbeta in rat hepatocytes, and this effect was inhibited by NFkappaB and MEK/ERK inhibitors. IL-6 mediated increase in C4BPbeta expression in rat hepatocytes, which leads to increased plasma PS-C4BP complex level and to decreased plasma PS activity, was inhibited by inhibition of STAT-3. CONCLUSION: LPS decreases both C4BPalpha and C4BPbeta expression via the NFkappaB and MEK/ERK pathways, whereas IL-6 specifically increases C4BPbeta expression via the STAT-3 pathway, causing an increase in plasma PS-C4BP complex, and thus decreasing the anticoagulant activity of PS.

Brainstem in Machado-Joseph disease: atrophy or small size?

Machado-Joseph disease (MJD), one of the most common types of hereditary spinocerebellar degeneration caused by abnormal expansion of the CAG repeat in the MJD1 gene, presents atrophy of the infratentorial structures neuropathologically and neuroradiologically. Although a significant positive correlation has been reported between infratentorial atrophy and the number of expanded CAG repeat units, the exact changing course of brainstem size in the individual case remains to be resolved. We investigated seven cases of genetically confirmed MJD longitudinally by magnetic resonance imaging with observation periods of 4.5-10.6 years. Measurement of the midsagittal areas of infratentorial structures disclosed progressive atrophy of the pontine base and cerebellum, which correlated significantly with age, whilst midbrain and pontine tegmentum showed atrophy with no significant progression, suggesting it was better identified as 'small size' and might have mostly been completed before the initial symptoms. Such differences between regions in atrophy progression must be caused by a difference in the neuropathological course.

Lipopolysaccharide-induced decreased protein S expression in liver cells is mediated by MEK/ERK signaling and NFkappaB activation: involvement of membrane-bound CD14 and toll-like receptor-4.

BACKGROUND: The vitamin K-dependent protein S (PS), mainly synthesized in hepatocytes and endothelial cells, plays a critical role in the anticoagulant activity of plasma. The decreased plasma level of PS in sepsis is associated with thrombotic tendency, but the mechanism is unclear. OBJECTIVES: In the present study, we examined the effect of lipopolysaccharide (LPS) on PS expression in vivo in rat liver, and in vitro in isolated hepatocytes and sinusoidal endothelial cells (SECs) from normal rats. RESULTS: LPS induced a progressive decrease of plasma PS antigen level up to 12 h with a slight recovery at 24 h, and a transient decrease of liver PS mRNA level at 4-8 h with a complete recovery at 24 h. In the in vitro studies, LPS decreased PS antigen and mRNA levels in both hepatocytes and SECs. After LPS treatment, tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6) and interferon-gamma (IFN-gamma) transiently increased in plasma. IL-6 increased the protein expression of PS from hepatocytes, while TNF-alpha decreased it from SECs. LPS increased CD14 in hepatocytes and decreased it in SECs, but did not affect toll-like receptor-4 (TLR-4) expression in both cells. Antirat CD14 and antirat TLR-4 antibodies inhibited LPS-induced NFkappaB activation, and a NFkappaB inhibitor suppressed LPS-induced decreased PS expression in both cells. Furthermore, MEK inhibitor blocked LPS-induced decreased PS expression in both cells. CONCLUSIONS: These findings suggest that LPS-induced decreased PS expression in hepatocytes and SECs is mediated by MEK/ERK signaling and NFkappaB activation and that membrane-bound CD14 and TLR-4 are involved in this mechanism. These findings may explain in part the decreased level of plasma PS and thrombotic tendency in sepsis.

Brain malformations caused by retroviral vector-mediated gene transfer of hippocampal cholinergic neurostimulating peptide precursor protein into the CNS via embryonic mice ventricles.

Hippocampal cholinergic neurostimulating peptide precursor protein (HCNP-pp) is a unique multifunctional protein, being not only the precursor of HCNP, which promotes the phenotype development of septo-hippocampal cholinergic neurons, but also the binding protein of phosphatidylethanolamine, ATP, Raf-1 kinase (known as "Raf-1 kinase inhibitory factor" in peripheral organs), and serine protease. We obtained a high-titer retroviral vector harboring HCNP-pp cDNA by the use of a modified packaging cell line and centrifugation, and by injecting it into embryonic mouse ventricles, we investigated the function of its gene product within the central nervous system (CNS). We found that efficient transduction into hippocampal pyramidal neurons can be achieved by injecting the vector into embryonic brain ventricles on embryonic day 14 (E14). Three days after receiving the intraventricular injection of the high-titer HCNP-pp retrovirus vector on E14, the tissues around the ventricles showed an overexpression of HCNP-pp. This was accompanied by a reduced amount of activated MEK and Erk (as analyzed by histochemical and Western blot methods), suggesting that HCNP-pp also regulates the MAP-kinase cascade within the CNS. Surprisingly, mouse brains that received the HCNP-pp retroviral vector showed massive malformation of the hippocampus and cerebellum when examined 30 days after birth. This shows that strictly regulated HCNP-pp gene expression is necessary for the normal development of the mouse brain, and that the moderate overexpression achieved by retroviral vector-mediated gene transfer is sufficient to cause severe abnormality of entire brain structures.

External validity of a randomised clinical trial of temporomandibular disorders: analysis of the patients who refused to participate in research.

PURPOSE: To assess the external validity of a randomised clinical trial (RCT) of a painful condition. METHOD: Consecutive patients with painful temporomandibular disorders (TMDs) were invited to participate in a clinical trial. Patients who refused to participate were compared to those who agreed to participate in this study with respect to degree of symptoms at time of presentation. RESULTS: The patients who refused to participate had more pain, and their condition interfered more with their daily life than those who accepted the invitation to participate. CONCLUSION: Selection bias in RCTs of painful conditions can skew the results, and external validity should be analysed before the results are generalised.

Classification of surgical difficulty in extracting impacted third molars.

Few studies have attempted to analyse preoperative factors that complicate the surgical removal of impacted mandibular third molars. We studied this problem in two steps. We found that difficulty in extraction is associated with depth (depth is deep occlusal level: level C), ramus relationship/space available (ramus relationship/space available is no space: class 3), width of root (the width of the middle root is thicker than that of the neck and the roots do not separate, incomplete roots excluded: bulbous), or a combination of these factors. The index was tested in 20 patients whose extractions were difficult, and 24 in whom they were not. The new index has an odds ratio (relative risk) of 62.3 (95% confidence interval, 9.3-415.9), a sensitivity of 0.85 and a specificity of 0.92. We consider that the new index is superior to the conventional Pederson's index.

Structural organization of lower marine nonvertebrate calmodulin genes.

The troponin C (TnC) superfamily genes generally possess five introns, and the positions where they are inserted are well conserved except for the fourth intron. Based on a structural comparison of TnC genes, we proposed that the common ancestor of TnC or TnC superfamily genes had no intron corresponding to the modern fourth intron, and therefore members of the superfamily have gained the fourth intron independently within each lineage. Here, we cloned calmodulin (CaM, one of the members of the TnC superfamily) cDNAs from two lower marine nonvertebrates, the sea anemone, Metridium senile, belonging to the Cnidaria, and the sponge, Halichondria okadai, belonging to the Porifera, and also determined their genomic organization. Chordate CaM genes generally possess five introns, but neither sea anemone nor sponge CaM has anything corresponding to the fourth intron of chordate CaMs, suggesting that the early metazoan CaM must have had only four introns. The modern fourth intron of chordate CaMs was acquired within the chordate lineage after nonvertebrate/chordate divergence. This notion concurs with our proposal explaining the evolution of the TnC superfamily genes.

Adjustment of prognostic effects in prevalent case-control studies on genotype.

Since genotypes are unchangeable, adjustment of prognostic effects in prevalent case-control studies may produce an unbiased estimate of odds ratio (OR) for disease occurrence. In this paper, the prognostic effects on OR is demonstrated, then three approaches to examine and/or adjust the OR are presented. The demonstration shows that the prognostic effects are larger in diseases with poor prognosis than in those with better prognosis. Genotypes increasing disease risk and fatality rate are underestimated, while those increasing the risk and improving prognosis are overestimated. The simplest approach to examine the OR derived from prevalent case-control studies is to conduct stratified analysis according to the interval between diagnosis and study enrollment. When the stratified analysis finds no substantial difference in the estimate, the OR reflects mainly the relative risk for disease occurrence. The proportion of genotype among putative cases at diagnosis can be estimated from prevalent cases by a logistic model, producing the OR adjusted for the interval from diagnosis. An incomplete-data case-control design is also applicable to adjust the prognostic effects. An actual prevalent case-control study on breast cancer is used to demonstrate the three approaches. They are useful to compensate the disadvantage of prevalent case-control studies.

Transport functions of riboflavin carriers in the rat small intestine and colon: site difference and effects of tricyclic-type drugs.

The present study was aimed at kinetically characterizing the newly found carrier-mediated riboflavin transport system in the rat colon, comparing it with that in the small intestine, and also probing the potential roles of these transport systems in intestinal drug absorption. Riboflavin transport, evaluated by measuring the initial uptake into everted intestinal tissue sacs, was saturable with a Michaelis constant (Km) of 0.13 microM and a maximum transport rate (Jmax) of 0.74 pmol/min/100 mg wet tissue weight (wtw) in the colon. Both the Km and the Jmax were smaller than those (0.57 microM and 4.26 pmol/min/100 mg wtw, respectively) in the small intestine, suggesting that the transport system in the colon has a higher affinity to substrates and a smaller transport capacity than its counterpart in the small intestine. The carrier-mediated riboflavin transport in the colon, similarly to that in the small intestine, was Na+-dependent and inhibited by lumiflavin, a riboflavin analogue with an isoalloxazine ring, but not by D-ribose, which forms the side-chain attached to the isoalloxazine ring in riboflavin. To further clarify the substrate specificities of the transport systems, we examined the effects of several drugs with a tricyclic structure similar to isoalloxazine ring on riboflavin transport. Chlorpromazine, a phenothiazine derivative, was found to inhibit riboflavin transport in both the small intestine and the colon. Methylene blue also was found to be a potent inhibitor in both sites. These results suggest that some tricyclic-type drugs could interfere with intestinal riboflavin absorption by specific carrier-mediated transport systems. These transport systems may play roles in the absorption of tricyclic-type drugs.

[Appearance of angry backfiring C-nociceptor (ABC) syndrome-like pain disorder in cross-side of one-side spinal anesthesia].

ABC (angry backfiring C-nociceptor) syndrome-like pain disorder categorized in sympathetic independent pain appeared after amputation during spinal anesthesia. A 69-year-old female who had undergone amputation of the right leg below knee 5 months before, received amputation of the left leg below knee this time because of diabetic neuropathy and gangrene of her both legs. There were no complications in her right leg after the former amputation. Spinal anesthesia was maintained in the left one-side by hyperbaric local anesthetic. After changing the body position from left lateral to supine, the left leg was completely anesthetized and the right leg was incompletely anesthetized with only loss of cold sensation. In this state, she had pain in her right leg, and this pain was relieved by intravenous lidocaine administration. It was indicated that this type of pain was caused by the presence of ABC syndrome probably after right leg amputation.

Randomized clinical trial of primary treatment for temporomandibular joint disk displacement without reduction and without osseous changes: a combination of NSAIDs and mouth-opening exercise versus no treatment.

OBJECTIVE: The effectiveness of nonsteroidal anti-inflammatory drugs (NSAIDs) and physical therapy for disk displacement without reduction is unknown. This study compared this treatment method with nontreatment controls. METHODS: Sixty patients with painful disk displacement without reduction and without osseous changes were randomly divided in 2 groups, consisting of NSAID and physical therapy and a nontreated control group. Both groups were observed at 2 weeks and, for those patients who did not show any improvement, again at 4 weeks. RESULTS: There was 60% improvement in the treatment group compared with 33% in the control group during the entire 4 weeks of the study. The number needed to treat for benefit was 3.75, with a 95% CI 2.103 to 65.935. CONCLUSIONS: A combination of NSAID and physical therapy for 4 weeks is effective as a primary treatment of patients with disk displacement without reduction and without osseous changes.

Glycosidase inhibition by cyclic sulfonium compounds.

Inhibitory activities of various cyclic sulfonium compounds including salacinol against several glycosidases were studied and some compounds showed significant inhibition. The sulfonium ion structure was found to be essential for the inhibitory activity. Specific inhibition of salacinol toward rice alpha-glucosidase was ascribed to the tether arm.

Genomic structure of the sandworm, Perinereis vancaurica tetradentata, troponin C.

Troponin C (TnC) superfamily genes essentially possess five introns, the positions of all but the fourth being highly conserved. The fourth intron is frequently absent from protostomian invertebrate genes, such as calmodulin or TnC. We previously proposed that the common ancestor of TnC superfamily genes never possessed an intron corresponding to today's fourth introns, and that members of the superfamily independently gained a fourth intron in the evolutionary pathway of each lineage. In the present study, we isolated the TnC cDNA from the sandworm, Perinereis vancaurica tetradentata and determined its genomic structure. Sandworm TnC appears to exist as a single copy gene consisting of six exons and five introns. The positions of the first, second, third and fifth introns are identical to other TnCs, but that of the fourth intron is unique. This is in good agreement with the above-mentioned scheme, i.e. the gain of the fourth intron of sandworm TnC might have occurred within the annelid lineage after annelida/mollusca divergence.