A lower starting dose of eltrombopag is efficacious in Japanese patients with previously treated chronic immune thrombocytopenia

BACKGROUND

Eltrombopag is an oral, non-peptide thrombopoietin receptor agonist that has shown efficacy and safety in chronic immune thrombocytopenia (ITP). However, ethnic differences in eltrombopag exposure have been reported: area under the curve exposure to eltrombopag was 87% greater among ITP patients of East Asian descent than among ITP patients of non-East Asian ITP descent.

OBJECTIVES

To evaluate the efficacy and safety of eltrombopag by using, in Japanese ITP patients, lower starting (12.5 mg) and maximum (50 mg) doses of eltrombopag than the standard starting (50 mg) and maximum (75 mg) doses approved in the USA and Europe.

PATIENTS

We examined 23 Japanese patients with previously treated chronic ITP with a platelet count of < 30,000 μL(-1) in a multicenter study comprising a randomized, double-blind, placebo-controlled phase for 6-week evaluation (15 eltrombopag, and eight placebo) and an open-label phase for 6-month evaluation (23 eltrombopag).

RESULTS AND CONCLUSIONS

The response rate (platelet count of ≥ 50,000 μL(-1) ) at week 6 of the 6-week double-blind phase was 60% in eltrombopag-treated patients and 0% in placebo-treated patients. Ten of 23 patients (43.5%) responded for ≥ 75% of predefined assessment visits during the 6-month open-label phase. Notably, 22% (5/23) of patients responded to 12.5 mg of eltrombopag, which was administered within the first 3 weeks of eltrombopag treatment. Bleeding decreased with eltrombopag treatment as compared with baseline. Eltrombopag was generally well tolerated; one patient experienced a transient ischemic attack on day 9. Eltrombopag (12.5-50 mg) is effective for the management of Japanese patients with chronic ITP (NCT00540423).

Transient expression of Xpn, an XLMR protein related to neurite extension, during brain development and participation in neurite outgrowth

KIAA2022 has been implicated as a gene responsible for expressing X-linked mental retardation (XLMR) proteins in humans. However, the functional role of KIAA2022 in the human brain remains unclear. Here, we revealed that depletion of Kiaa2022 inhibits neurite outgrowth of PC12 cells, indicating that the gene participates in neurite extension. Thus, we termed Kiaa2022 as an XLMR protein related to neurite extension (Xpn). Using the mouse brain as a model and ontogenetic analysis of Xpn by real-time PCR, we clearly demonstrated that Xpn is expressed transiently during the late embryonic and perinatal stages. In situ hybridization histochemistry further revealed that Xpn-expressing neurons could be categorized ontogenetically into three types. The first type showed transient expression of Xpn during development. The second type maximally expressed Xpn during the late embryonic or perinatal stage. Thereafter, Xpn expression in this type of neuron decreased gradually throughout development. Nevertheless, a significant level of Xpn expression was detected even into adulthood. The third type of neurons initiated expression of Xpn during the embryonic stage, and continued to express the gene throughout the remaining developmental stages. Subsequent immunohistochemical analysis revealed that Xpn was localized to the nucleus and cytoplasm throughout brain development. Our findings indicate that Xpn may participate in neural circuit formation during developmental stages via nuclear and cytoplasmic Xpn. Moreover, disturbances of this neuronal circuit formation may play a role in the pathogenesis of mental retardation.

Superconductivity induced by longitudinal ferromagnetic fluctuations in UCoGe

From detailed angle-resolved NMR and Meissner measurements on a ferromagnetic (FM) superconductor UCoGe (T(Curie)∼2.5  K and T(SC)∼0.6  K), we show that superconductivity in UCoGe is tightly coupled with longitudinal FM spin fluctuations along the c axis. We found that magnetic fields along the c axis (H∥c) strongly suppress the FM fluctuations and that the superconductivity is observed in the limited magnetic-field region where the longitudinal FM spin fluctuations are active. These results, combined with model calculations, strongly suggest that the longitudinal FM spin fluctuations tuned by H∥c induce the unique spin-triplet superconductivity in UCoGe. This is the first clear example that FM fluctuations are intimately related with superconductivity.

Different patterns of fornix damage in idiopathic normal pressure hydrocephalus and Alzheimer disease

BACKGROUND AND PURPOSE

The fornix contains efferent fibers of the hippocampus and is in close contact with the corpus callosum. Part of the fornix is directly attached to the corpus callosum, and another part is suspended from the corpus callosum via the septum pellucidum. DTI can be used to evaluate the morphology and microstructural integrity of the fornix. We examined the pattern of fornix damage in patients with iNPH or AD.

MATERIALS AND METHODS

We enrolled 22 patients with iNPH, 20 with AD, and 20 healthy controls. DTI data were obtained. The morphology (volume, length, and mean cross-sectional area) and FA values of the fornix were evaluated by using tract-specific analysis and compared among groups.

RESULTS

The volume, cross-sectional area, and FA value of the fornix were significantly smaller in patients with iNPH than in controls, whereas the length was significantly greater. In patients with AD, the volume, mean cross-sectional area, and FA value of the fornix were significantly smaller than those in controls, whereas the length was not altered. The fornix was significantly longer in patients with iNPH than in patients with AD, whereas the volume and cross-sectional areas were significantly smaller.

CONCLUSIONS

Our results suggest that the different pathogeneses of these diseases lead to fornix damage through different mechanisms: through mechanical stretching due to lateral ventricular enlargement and corpus callosum deformation in patients with iNPH, and through degeneration secondary to hippocampal atrophy in patients with AD.

Status of ion sources at National Institute of Radiological Sciences

The National Institute of Radiological Sciences (NIRS) maintains various ion accelerators in order to study the effects of radiation of the human body and medical uses of radiation. Two electrostatic tandem accelerators and three cyclotrons delivered by commercial companies have offered various life science tools; these include proton-induced x-ray emission analysis (PIXE), micro beam irradiation, neutron exposure, and radioisotope tracers and probes. A duoplasmatron, a multicusp ion source, a penning ion source (PIG), and an electron cyclotron resonance ion source (ECRIS) are in operation for these purposes. The Heavy-Ion Medical Accelerator in Chiba (HIMAC) is an accelerator complex for heavy-ion radiotherapy, fully developed by NIRS. HIMAC is utilized not only for daily treatment with the carbon beam but also for fundamental experiments. Several ECRISs and a PIG at HIMAC satisfy various research and clinical requirements.

White matter alteration in idiopathic normal pressure hydrocephalus: tract-based spatial statistics study

BACKGROUND AND PURPOSE

White matter alteration in iNPH has not been well-investigated. TBSS is a voxelwise statistical analysis developed for DTI data. We aimed to elucidate the cerebral white matter alteration in patients with iNPH by using DTI and to test the accuracy of TBSS analysis.

MATERIALS AND METHODS

DTI data were obtained from 20 patients with iNPH and 20 age- and sex-matched controls. The FA values were evaluated by using TBSS, region-of-interest and tract-specific analysis of the CST. The accuracy of TBSS analysis was tested by using "back-projection" of TBSS results and by comparing the TBSS analysis results with those of region-of-interest and tract-specific analysis.

RESULTS

Back-projection of the TBSS results showed accurate registration of the whole brain, with the exception of parts of the thalamus, fornix, and white matter around the posterior body of the lateral ventricle. The TBSS analysis results were consistent with those of the region-of-interest analysis and tract-specific analysis. In patients with iNPH compared with control subjects, the FA values were significantly decreased in parts of the corpus callosum, periventricular white matter, and juxtacortical white matter in the frontal and parietal lobes. In contrast, FA values were significantly increased in the internal capsule, extending to the white matter in the centrum semiovale.

CONCLUSIONS

Our results suggest that patients with iNPH have various patterns of white matter damage and that TBSS analysis is a promising tool for performing accurate voxelwise statistical analysis of the iNPH brain, with the exception of misregistered areas.

Metamagnetic behavior and Kondo breakdown in heavy-fermion CeFePO

We report that nonmagnetic heavy-fermion (HF) iron oxypnictide CeFePO with two-dimensional XY-type anisotropy shows a metamagnetic behavior at the metamagnetic field H(M)≃4  T perpendicular to the c axis and that a critical behavior is observed around H(M). Although the magnetic character is entirely different from that in other Ce-based HF metamagnets, H(M) in these metamagnets is linearly proportional to the inverse of the effective mass, or to the temperature where the susceptibility shows a peak. This finding suggests that H(M) is a magnetic field breaking the local Kondo singlet, and the critical behavior around H(M) is driven by the Kondo breakdown accompanied by the Fermi-surface instability.

A novel gain-of-function KCNJ2 mutation associated with short-QT syndrome impairs inward rectification of Kir2.1 currents

AIMS

Short-QT syndrome (SQTS) is a recently recognized disorder associated with atrial fibrillation (AF) and sudden death due to ventricular arrhythmias. Mutations in several ion channel genes have been linked to SQTS; however, the mechanism remains unclear. This study describes a novel heterozygous gain-of-function mutation in the inward rectifier potassium channel gene, KCNJ2, identified in SQTS.

METHODS AND RESULTS

We studied an 8-year-old girl with a markedly short-QT interval (QT = 172 ms, QTc = 194 ms) who suffered from paroxysmal AF. Mutational analysis identified a novel heterozygous KCNJ2 mutation, M301K. Functional assays displayed no Kir2.1 currents when M301K channels were expressed alone. However, co-expression of wild-type (WT) with M301K resulted in larger outward currents than the WT at more than -30 mV. These results suggest a gain-of-function type modulation due to decreased inward rectification. Furthermore, we analysed the functional significance of the amino acid charge at M301 (neutral) by changing the residue. As with M301K, in M301R (positive), the homozygous channels were non-functional, whereas the heterozygous channels demonstrated decreased inward rectification. Meanwhile, the currents recorded in M301A (neutral) showed normal inward rectification under both homo- and heterozygous conditions. Heterozygous overexpression of WT and M301K in neonatal rat ventricular myocytes exhibited markedly shorter action potential durations than the WT alone.

CONCLUSION

In this study, we identified a novel KCNJ2 gain-of-function mutation, M301K, associated with SQTS. Functional assays revealed no functional currents in the homozygous channels, whereas impaired inward rectification demonstrated under the heterozygous condition resulted in larger outward currents, which is a novel mechanism predisposing SQTS.

Dental caries area of rat molar expanded by cigarette smoke exposure

OBJECTIVES

Passive smoking is the involuntary inhalation of cigarette smoke (CS) and has an adverse impact on oral health. We examined the effect of CS exposure on caries risk and experimental dental caries.

METHODS

Experimental dental caries was induced in rat maxillary molars which were inoculated orally with Streptococcus mutans MT8148 and maintained on a cariogenic diet (diet 2000) and high sucrose water during the experimental period. CS-exposed rats were intermittently housed in an animal chamber with whole-body exposure to CS until killed. Whole saliva was collected before CS exposure (day 0) and for 30 days after the start of CS exposure. Saliva secretion was stimulated by administration of isoproterenol and pilocarpine after anesthesia. Maxillary molars were harvested on day 31.

RESULTS

The increase in body weight of the CS-exposed rats was less than that of the control rats. Salivary flow rate, concentration of S. mutans in the stimulated saliva and caries activity score did not significantly differ between 0 and 30 days after the start of CS exposure. Histological examination of the caries-affected area on maxillary molars 30 days after CS exposure showed expansion compared to control rats. In the electron probe microanalysis, no differences were observed between the mineral components of the CS-exposed teeth and the control teeth.

CONCLUSION

These results suggest that CS exposure expands the caries-affected area in the maxillary molars of the rat.

Altered microstructure in corticospinal tract in idiopathic normal pressure hydrocephalus: comparison with Alzheimer disease and Parkinson disease with dementia

BACKGROUND AND PURPOSE

Previous neuropathologic studies in chronic hydrocephalus have suggested the presence of white matter damage, presumably from mechanical pressure due to ventricular enlargement and metabolic derangement. This study aimed to investigate the diffusional properties of the CST in patients with iNPH by using DTI and to determine whether this method could be used as a new diagnostic tool to differentiate patients with iNPH from those with AD and PDD and control subjects.

MATERIALS AND METHODS

We enrolled 18 patients with iNPH, 11 patients with AD, 11 patients with PDD, and 19 healthy control subjects. Diffusion tensor metrics of the segmented CST, including FA values, axial eigenvalues, and radial eigenvalues, were evaluated by using tract-specific analysis. The anisotropy color-coding tractography of the CST was visually evaluated. The DTI findings were compared among groups.

RESULTS

Tract-specific analysis of the CST showed that FA values and axial eigenvalues were significantly increased (P < .001), whereas radial eigenvalues were not significantly altered, in patients with iNPH compared with other subjects. The CST tractographic images in patients with iNPH was visually different from those in other subjects (P < .001). In discriminating patients with iNPH from other subjects, the CST FA values had a sensitivity of 94% and specificity of 80% at a cutoff value of 0.59.

CONCLUSIONS

Our results suggest that patients with iNPH have altered microstructures in the CST. Quantitative and visual CST evaluation by using DTI may be useful for differentiating patients with iNPH from patients with AD or PDD or healthy subjects.

Origin of activation energy in a superionic conductor

The characteristics of cation diffusion with many-body effects are discussed using Ag β-alumina as an example of a superionic conductor. Polarized Raman spectra of Ag β-alumina have been measured at room temperature. The interatomic potentials were determined by a non-linear least square fitting between the phonon eigenvalues from the Raman observations and a dynamical matrix calculation based on a rigid-ion model. The obtained potential parameters for the model crystal of Ag β-alumina successfully reproduce the macroscopic properties with respect to the heat capacity, isothermal compressibility and self-diffusion constant. A molecular dynamics (MD) calculation has been carried out using the model crystal of Ag β-alumina to understand the many-body effects for the fast ionic diffusion. It was found that the Ag-Ag repulsion by excess Ag defects significantly reduced the cost of the energy difference of the occupancy between the stable and metastable sites. It is possible for the system to take various configurations of the mobile ions through defects easily, and then the fast ionic diffusion will appear. On the other hand, the Ag-Ag repulsion changes the dynamics of the Ag ions from a random hopping to a cooperative motion. In the cooperative motion, the ionic transport becomes difficult due to the additional energy required for the structural relaxation of the surrounding Ag ions. We propose a new insight into the superionic conduction, that is, the activation energy for the ionic transport is composed of two kinds of elements: a 'static' activation energy and a 'dynamic' one. The static activation energy is the cost of the averaged energy difference in the various structural configurations in the equilibrium state. The dynamic activation energy is the additional energy required for the structural relaxation induced by the jump process.

KCNE5 (KCNE1L) variants are novel modulators of Brugada syndrome and idiopathic ventricular fibrillation

BACKGROUND

Brugada syndrome (BrS) has a significantly higher incidence among the male sex. Among genes coding ion channels and their modulatory proteins, KCNE5 (KCNE1L) is located in the X chromosome and encodes an auxiliary β-subunit for K channels. KCNE5 has been shown to modify the transient outward current (I(to)), which plays a key role in determining the repolarization process in the myocardium. This study investigated whether KCNE5 mutations could be responsible for BrS and other idiopathic ventricular fibrillation (IVF).

METHODS AND RESULTS

In 205 Japanese patients with BrS or IVF who tested negative for SCN5A mutation, we conducted a genetic screen for KCNE5 variants. We identified 2 novel KCNE5 variants: p.Y81H in 3 probands and p.[D92E;E93X] in 1 proband from 4 unrelated families. Y81H was identified in 1 man and 2 women; D92E;E93X was found in a 59-year-old man. All probands received implantable cardioverter-defibrillators. Functional consequences of the KCNE5 variants were determined through biophysical assay using cotransfection with KCND3 or KCNQ1. In the experiments with KCND3, which encodes Kv4.3, I(to) was significantly increased for both KCNE5 variants compared to wild type. In contrast, there were no significant changes in current properties reconstructed by KCNQ1+ wild type KCNE5 and the 2 variants. With the simulation model, both variants demonstrated notch-and-dome or loss-of-dome patterns.

CONCLUSIONS

KCNE5 modulates I(to), and its novel variants appeared to cause IVF, especially BrS, in male patients through gain-of-function effects on I(to). Screening for KCNE5 variants is relevant for BrS or IVF.

Structures of Bonding Interface by Forming Hydrogen Bridges

Direct bonding by forming interface hydrogen bridges has been investigated for both combinations of AI.Si and Al.PZT{Pb(Zr,Ti)03). Hydrogen bridges are formed between OH-groups and oxygen atoms on each bonding surface. Therefore, the surface adsorbing of OH-groups (hydrophilic treatment) is required to the pre-treatment of bonding surface. In this study, two ways of conventional hydrophilic treatment by wet-process and novel treatment by the surface bombardment of hydro-ions(H2O+, OH+, O+, and others) in vacuum (dry-process) have been examined.

Each bonding surface is contacted in the air after the hydrophilic treatment. In the case of hydrophilic treatment by wet-process, the bonding strength of Al-Si shows about 20 MPa after the heat treatment of above 350°C. As for the dry-process, both combinations of At.Si and AI.PZT are bondable, and their strength shows the similar tendency as wet-process with the time and the temperature of heat treatment. However, the bonding area increases more quickly than the ones of wet process. From the results of SIMS and cross-sectional TEM observation of AlSi bonding interface, it is suggested that these bonding are caused by the hydrogen bond formation without interfacial water molecules.

Characterization of a new animal model of metabolic syndrome: the DahlS.Z-Lepr(fa)/Lepr(fa) rat

Objective:

The DahlS.Z-Lepr^fa/Lepr^fa (DS/obese) rat strain was established from a cross between Dahl salt-sensitive rats and Zucker fatty (fa/fa) rats, the latter of which harbor a missense mutation in the leptin receptor gene (Lepr). We examined whether DS/obese rats might be a suitable animal model of metabolic syndrome in humans.

Methods:

The systemic pathophysiological and metabolic characteristics of DS/obese rats were determined and compared with those of homozygous lean littermates, namely, DahlS.Z-Lepr⁺/Lepr⁺ (DS/lean) rats.

Results:

Systolic blood pressure was higher in DS/obese rats fed a normal diet than in DS/lean rats at 11 weeks of age and thereafter. The survival rate of DS/obese rats was significantly lower than that of DS/lean rats at 18 weeks. Body weight, visceral and subcutaneous fat mass, as well as heart, kidney and liver weights, were increased in DS/obese rats at 18 weeks compared with DS/lean rats. Serum low-density lipoprotein (LDL)-cholesterol, triglyceride and insulin concentrations, as well as the ratio of LDL-cholesterol to high-density lipoprotein-cholesterol levels, were increased in DS/obese rats, whereas serum glucose concentration did not differ significantly between DS/obese and DS/lean rats. Creatinine clearance was decreased and urinary protein content was increased in DS/obese rats, which also manifested lipid accumulation in the liver and elevation of serum alanine aminotransferase levels.

Conclusion:

These results show that the phenotype of DS/obese rats is similar to that of humans with metabolic syndrome, and that these animals may thus be an appropriate model for this condition.

Differential responding of autonomic function to histamine H₁ antagonism in irritable bowel syndrome

BACKGROUND

The role of histamine in the pathophysiology of irritable bowel syndrome (IBS) is largely unknown. Dysfunction of the autonomic nervous system (ANS) in IBS patients is also not fully confirmed. We hypothesized that blockade of histamine H₁ receptors affects ANS responses differently between IBS subjects and controls.

METHODS

Subjects were 12 IBS subjects and 12 age- and sex-matched controls. Either 100 μg kg⁻¹ chlorphenamine or the same amount of saline was administered on different days. The rectum was stimulated with electrical currents of 0 mA (sham) or 30 mA. Autonomic nervous system function was measured using mean arterial pressure (MAP), heart rate (HR), high frequency (HF) component of HR variability, low frequency/high frequency ratio (LF/HF ratio) and plasma catecholamines and histamine. Subjective perceived stress during the examination was evaluated on an ordinate scale.

KEY RESULTS

Mean arterial pressure showed significant effects of diagnosis (P < 0.05) and drug × diagnosis interaction (P < 0.05). The MAP significantly increased after chlorphenamine administration in IBS subjects, but not in controls. Heart rate revealed a significant drug effect (P < 0.001), which decreased after chlorphenamine administration in controls, but not in IBS subjects. Perceived stress significantly increased by rectal stimulation (P < 0.001) and a significant stimulus × diagnosis interaction (P < 0.05) was revealed, indicating greater reduction in IBS subjects by chlorphenamine.

CONCLUSION & INFERENCES

Sympathetic vasomotor tone in IBS subjects differentially responded on administration of a histamine H₁ antagonist to that of controls. These findings suggest an increased histaminergic activity in IBS subjects.

Anisotropic magnetic fluctuations in the ferromagnetic superconductor UCoGe studied by direction-dependent 59Co NMR measurements

We have carried out direction-dependent 59Co NMR experiments on a single crystal sample of the ferromagnetic superconductor UCoGe in order to study the magnetic properties in the normal state. The Knight-shift and nuclear spin-lattice relaxation rate measurements provide microscopic evidence that both static and dynamic susceptibilities are ferromagnetic with strong Ising anisotropy. We discuss that superconductivity induced by these magnetic fluctuations prefers spin-triplet pairing state.

DISC1 regulates cell-cell adhesion, cell-matrix adhesion and neurite outgrowth

Disrupted-in-schizophrenia 1 (DISC1) is a promising susceptibility gene for major mental illness. Recent studies have implicated DISC1 in key neurodevelopmental processes, including neurite outgrowth, neuronal migration and proliferation. Here, we report that DISC1 regulates cell-cell and cell-matrix adhesion and neurite outgrowth. DISC1 overexpression increased expression of the adherence junction protein N-cadherin and enhanced cell-cell adhesion. The increased N-cadherin accumulated in the areas of cell-cell contact. DISC1 overexpression also enhanced cell-matrix adhesion by inducing expression of beta1-integrin protein. In the presence of nerve growth factor (NGF), DISC1 overexpression increased beta1-integrin expression at the cell membrane and growth cone. NGF-induced neurite extension was enhanced by DISC1, and anti-beta1-integrin antibody reduced the neurite outgrowth of DISC1-overexpressing cells to the control level. Furthermore, DISC1 also regulated N-cadherin and beta1-integrin expression at the cell membrane in primary neurons. We conclude that DISC1 regulates cell-cell adhesion and cell-matrix adhesion by regulating the expression of adhesion molecules.

Trigger digits in diabetes: their incidence and characteristics

The purpose of this study was to investigate the incidence and characteristics of trigger digits in patients with diabetes. A questionnaire about trigger digit was completed by 544 patients with diabetes. Ten percent of the patients had a history of trigger digits and 4% had multiple digit involvement. The risk was significantly higher in insulin-dependent patients. The average duration of diabetes was significantly longer in the multiple digit group. Independently, the medical records of 132 trigger digit patients who underwent surgery were reviewed. Twenty-seven patients had diabetes, and 62 patients had multiple digit involvement. Involvement of more than three digits was significantly related to co-existing diabetes. In patients with diabetes, the incidence of trigger digits was about four times higher than in the general population. Screening for diabetes may be warranted in patients with involvement of more than three digits.