Voxel-based morphometry of the marmoset brain: In vivo detection of volume loss in the substantia nigra of the MPTP-treated Parkinson's disease model

Movement dysfunction in Parkinson's disease (PD) is caused by the degeneration of dopaminergic (DA) neurons in the substantia nigra (SN). Here, we established a method for voxel-based morphometry (VBM) and automatic tissue segmentation of the marmoset monkey brain using a 7-T animal scanner and applied the method to assess DA degeneration in a PD model, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated animals, with tyrosine-hydroxylase staining. The most significant decreases of local tissue volume were detected in the bilateral SN of MPTP-treated marmoset brains (-53.0% in right and -46.5% in left) and corresponded with the location of DA neurodegeneration found in histology (-65.4% in right). In addition to the SN, the decreases were also confirmed in the locus coeruleus, and lateral hypothalamus. VBM using 7-T MRI was effective in detecting volume loss in the SN of the PD-model marmoset. This study provides a potential basis for the application of VBM with ultra-high field MRI in the clinical diagnosis of PD. The developed method may also offer value in automatic whole-brain evaluation of structural changes for the marmoset monkey.

Water's tensile strength measured using an optofluidic chip

In this paper, for the first time, the tensile strength of water is directly measured using an optofluidic chip based on the displacement of air-water interface deformation with homogeneous nucleation. When water in a microchannel is stretched dynamically via laser-induced shock reflection at the air-water interface, the shock pressures are determined by measuring the displacements of the deformed interface. Observation of the vapor bubbles is used as a probe to identify the cavitation threshold with a critical distance, and the tensile strength of water at 20 °C is measured to be -33.3 ± 2.8 MPa. This method can be extended to investigate the tensile strength of other soft materials such as glycerol, which is measured to be -59.8 ± 10.7 MPa at 20 °C.

Long-distance propagation of a surface plasmon on the surface of a ferromagnetic metal

A method for the reduction of the propagation loss of surface plasmons was proposed and experimentally demonstrated. A plasmonic structure, which contains a metal and two dielectric layers of different refractive indexes, is proposed in order to optimize the optical confinement and to reduce the propagation loss of the surface plasmons. Long-distance propagation of a surface plasmon on the surface of a ferromagnetic metal was demonstrated. A low propagation loss of 0.17 dB/μm for a surface plasmon in a Fe/MgO/AlGaAs plasmonic structure was achieved.

Droplet generation via a single bubble transformation in a nanofluidic channel

Here we report the first demonstration on droplet generation from the transformation of a single bubble in a nanofluidic channel by a laser-induced jet. A viscous two-dimensional Rayleigh-Plesset-type model is derived to describe the bubble dynamics in the nanofluidic channel, which accounts for the effect of shear stresses from the channel wall. The droplet generation (number and volume) is investigated experimentally by controlling the jet velocity via laser energy and distance. This study expands the understanding of jetting in the nanofluidic channel and demonstrates a novel method for femtoliter-volume single or multiple droplet formation. It is envisioned that this work will open new doors in on-demand generation of nanodroplets.

Increased Salt Sensitivity in Obese Hypertension:Role of the Sympathetic Nervous System

Salt sensitivity of blood pressure (BP) is increased in hypertension associated with obesity and/or metabolic disorders. Reversely, patients with salt-sensitive hypertension often reveal metabolic disorders. Thus, salt excess and overeating, which are major bad dietary habits in civilized men and women, strengthen the effect to increase BP each other. Actually, there are similar pathophysiological characteristics between hypertension induced by high salt intake and obesity: the sympathetic excitation has been suggested to contribute to increase in BP of the two types of hypertension. Also, several investigators indicated that reactive oxygen species (ROS) production is increased in important organs of salt-sensitive and/or obese hypertension. Recently, we demonstrated that, in salt- and obesity-induced hypertension, hypothalamic ROS levels was elevated and intracerebroventricular antioxidants suppress BP and renal sympathetic nerve activity more profoundly, compared to their control. Thus, it is suggested that brain ROS overproduction increases BP through central symapthoexcitation in salt- and obesity-induced hypertension, which are often associated.

Expression of myeloperoxidase in acute myeloid leukemia blasts mirrors the distinct DNA methylation pattern involving the downregulation of DNA methyltransferase DNMT3B

Myeloperoxidase (MPO) has been associated with both a myeloid lineage commitment and favorable prognosis in patients with acute myeloid leukemia (AML). DNA methyltransferase inhibitors (decitabine and zeburaline) induced MPO gene promoter demethylation and MPO gene transcription in AML cells with low MPO activity. Therefore, MPO gene transcription was directly and indirectly regulated by DNA methylation. A DNA methylation microarray subsequently revealed a distinct methylation pattern in 33 genes, including DNA methyltransferase 3 beta (DNMT3B), in CD34-positive cells obtained from AML patients with a high percentage of MPO-positive blasts. Based on the inverse relationship between the methylation status of DNMT3B and MPO, we found an inverse relationship between DNMT3B and MPO transcription levels in CD34-positive AML cells (P=0.0283). In addition, a distinct methylation pattern was observed in five genes related to myeloid differentiation or therapeutic sensitivity in CD34-positive cells from AML patients with a high percentage of MPO-positive blasts. Taken together, the results of the present study indicate that MPO may serve as an informative marker for identifying a distinct and crucial DNA methylation profile in CD34-positive AML cells.

Synthesis of inosine 6-phosphate diesters via phosphitylation of the carbonyl oxygen

Inosine derivatives bearing a phosphodiester group at the O(6)-position of the nucleobase were synthesized via phosphitylation of the carbonyl oxygen using phosphoramidites activated by non-nucleophilic acidic activators.

B-type natriuretic peptide levels are decreased by reducing dietary salt intake in patients with compensated heart failure with preserved ejection fraction

BACKGROUND

Dietary salt restriction is believed to be a mainstay in the management of patients with heart failure. However, the effect of salt intake on heart failure has not been well evaluated in outpatient medical practice.

AIMS

The aim of the present study was to assess the hypothesis that B-type natriuretic peptide (BNP) level, as an objective marker of heart failure, is associated with salt intake in patients with heart failure.

METHODS

One hundred and thirteen consecutive patients with mild compensated heart failure (77 ± 10 years old, 51 female) were included. We estimated dietary salt intake by the concentration of sodium and creatinine in spot urine. We measured BNP at the time of urine sampling and assessed the relationship between the % changes in BNP levels (%ΔBNP) and the changes in the estimated daily salt excretion (ΔNaCl) during the follow-up period.

RESULTS

The baseline median BNP level was 150 (interquartile range: 83-263) pg/mL and the estimated daily salt excretion was 162 ± 45 mmol/day. There was a positive correlation between %ΔBNP and ΔNaCl (r = 0.61, P < 0.01). Multiple regression analysis revealed that %ΔBNP was associated with ΔNaCl (P < 0.01), but not with changes in systolic blood pressure and bodyweight.

CONCLUSIONS

Changes in BNP levels were associated with changes in the estimated daily salt excretion in outpatients with compensated heart failure. Salt restriction may be beneficial for the management of patients with heart failure.

Highly sensitive nanoscale spin-torque diode

Highly sensitive microwave devices that are operational at room temperature are important for high-speed multiplex telecommunications. Quantum devices such as superconducting bolometers possess high performance but work only at low temperature. On the other hand, semiconductor devices, although enabling high-speed operation at room temperature, have poor signal-to-noise ratios. In this regard, the demonstration of a diode based on spin-torque-induced ferromagnetic resonance between nanomagnets represented a promising development, even though the rectification output was too small for applications (1.4 mV mW(-1)). Here we show that by applying d.c. bias currents to nanomagnets while precisely controlling their magnetization-potential profiles, a much greater radiofrequency detection sensitivity of 12,000 mV mW(-1) is achievable at room temperature, exceeding that of semiconductor diode detectors (3,800 mV mW(-1)). Theoretical analysis reveals essential roles for nonlinear ferromagnetic resonance, which enhances the signal-to-noise ratio even at room temperature as the size of the magnets decreases.