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.

Purification and comparison of native and recombinant tRNA-guanine transglycosylases from Methanosarcina acetivorans

Many archaeal tRNAs have archaeosine (G(+)) at position 15 in the D-loop and this is thought to strengthen the tertiary interaction with C48 in the V-loop. In the first step of G(+) biosynthesis, archaeosine tRNA-guanine transglycosylase (ArcTGT)(1) catalyzes the base exchange reaction from guanine to 7-cyano-7-deazaguanine (preQ(0)). ArcTGT is classified into full-size or split types, according to databases of genomic information. Although the full-size type forms a homodimeric structure, the split type has been assumed to form a heterotetrameric structure, consisting of two kinds of peptide. However, there has been no definitive evidence for this presented to date. Here, we show that native ArcTGT could be isolated from Methanosarcina acetivorans and two peptides formed a robust complex in cells. Consequently, the two peptides function as actual subunits of ArcTGT. We also overexpressed recombinant ArcTGT in Escherichia coli cells. Product was successfully obtained by co-overexpression of the two subunits but one subunit alone was not adequately expressed in soluble fractions. This result suggests that interaction between the two subunits may contribute to the conformational stability of split ArcTGT. The values of the kinetic parameters for the recombinant and native ArcTGT were closely similar. Moreover, tRNA transcript with preQ(0) at position 15 was successfully prepared using the recombinant ArcTGT. This tRNA transcript is expected to be useful as a substrate for studies seeking the enzymes responsible for G(+) biosynthesis.

Transcriptome analyses of early cucumber fruit growth identifies distinct gene modules associated with phases of development

ABBACKGROUND: Early stages of fruit development from initial set through exponential growth are critical determinants of size and yield, however, there has been little detailed analysis of this phase of development. In this study we combined morphological analysis with 454 pyrosequencing to study transcript level changes occurring in young cucumber fruit at five ages from anthesis through the end of exponential growth.

RESULTS

The fruit samples produced 1.13 million ESTs which were assembled into 27,859 contigs with a mean length of 834 base pairs and a mean of 67 reads per contig. All contigs were mapped to the cucumber genome. Principal component analysis separated the fruit ages into three groups corresponding with cell division/pre-exponential growth (0 and 4 days post pollination (dpp)), peak exponential expansion (8dpp), and late/post-exponential expansion stages of growth (12 and 16 dpp). Transcripts predominantly expressed at 0 and 4 dpp included homologs of histones, cyclins, and plastid and photosynthesis related genes. The group of genes with peak transcript levels at 8dpp included cytoskeleton, cell wall, lipid metabolism and phloem related proteins. This group was also dominated by genes with unknown function or without known homologs outside of cucurbits. A second shift in transcript profile was observed at 12-16dpp, which was characterized by abiotic and biotic stress related genes and significant enrichment for transcription factor gene homologs, including many associated with stress response and development.

CONCLUSIONS

The transcriptome data coupled with morphological analyses provide an informative picture of early fruit development. Progressive waves of transcript abundance were associated with cell division, development of photosynthetic capacity, cell expansion and fruit growth, phloem activity, protection of the fruit surface, and finally transition away from fruit growth toward a stage of enhanced stress responses. These results suggest that the interval between expansive growth and ripening includes further developmental differentiation with an emphasis on defense. The increased transcript levels of cucurbit-specific genes during the exponential growth stage may indicate unique factors contributing to rapid growth in cucurbits.

Spin pumping driven by bistable exchange spin waves

Spin pumping driven by bistable exchange spin waves is demonstrated in a Pt/Y3Fe5O12 film under parametric excitation. In the Pt/Y3Fe5O12 film, the spin pumping driven by parametric excitation selectively enhances the relaxation of short-wavelength exchange spin waves, indicating strong coupling between the exchange spin waves and spin currents at the interface through efficient spin transfer. The parametric spin pumping, furthermore, allows direct access to nonlinear spin wave dynamics in combination with the inverse spin Hall effect, revealing unconventional bistability of the exchange spin waves.

Dietary intake of vitamin B12 and folic acid is associated with lower blood pressure in Japanese preschool children

BACKGROUND

An elevated plasma homocysteine level is an independent risk factor for high blood pressure and cardiovascular disease, and its level is regulated by three vitamins; vitamin B6, B12, and folic acid. Until now, the association between the intake of these vitamins and blood pressure has been examined only in adult populations. We purposed to examine the association between dietary intake of these three vitamins and blood pressure of young children.

METHODS

We conducted a cross-sectional study at Japanese preschools in 2006. Blood pressure was measured among 418 children aged 3-6 years. Diets including vitamins were assessed by a 3-day dietary record. We compared the blood pressure levels among the four groups defined according to quartile of energy-adjusted vitamin intake by using analysis of covariance after controlling for age, sex, and body mass index.

RESULTS

The mean systolic blood pressure was 6.6 mm Hg lower and the mean diastolic blood pressure was 5.7 mm Hg lower in the highest quartile than in the lowest quartile of vitamin B12 intake (P for trend was <0.001 and 0.006, respectively). The mean systolic blood pressure was 4.1 mm Hg lower in the highest quartile than in the lowest quartile of folic acid intake (P for trend = 0.004). Vitamin B6 intake was not significantly associated with blood pressure.

CONCLUSIONS

The data suggest that high intakes of folic acid and vitamin B12 are associated with lower levels of blood pressure among preschool children.

The diagnostic accuracy of high-resolution endoscopy, autofluorescence imaging and narrow-band imaging for differentially diagnosing colon adenoma

BACKGROUND AND STUDY AIMS

Conventional colonoscopy can result in unnecessary biopsy or endoscopic resection due to its inability to distinguish adenomas from hyperplastic polyps. This study therefore evaluated the efficacy of high-resolution endoscopy (HRE), autofluorescence imaging (AFI), and narrow-band imaging (NBI) in discriminating colon adenoma from hyperplastic polyps.

PATIENTS AND METHODS

This was a prospective multicenter study in patients undergoing AFI and NBI examinations. HRE, AFI, and NBI images were classified into two groups based on morphological characteristics, the predominant color intensities, and the visibility of meshed capillary vessels, respectively. Each of the endoscopic photographs were independently evaluated by a single endoscopist. The images were then assessed by three specialists and three residents, the latter having performed < 500 colonoscopies and < 30 NBI and AFI examinations. Diagnostic test statistics were calculated to compare the accuracy in differentiating colon adenoma from hyperplastic polyps for each method.

RESULTS

A total of 183 patients were enrolled in the study and 339 adenomas and 85 hyperplastic polyps were identified. AFI and NBI could distinguish adenoma from hyperplastic polyps with an accuracy of 84.9 % and 88.4 %, respectively, whereas HRE exhibited an accuracy of 75.9 %. In the 358 lesions in which the AFI diagnosis was consistent with that of NBI, the accuracy, sensitivity, and specificity were high, at 91.9 %, 92.7 %, and 92.9 %, respectively. During the study comparing specialists and residents, AFI and NBI dramatically improved the diagnostic accuracy of residents from 69.1 % to 86.1 % and 84.7 %, respectively.

CONCLUSIONS

Both AFI and NBI are considered to be feasible tools that can discriminate colon adenoma from hyperplastic polyps, and their use may be particularly beneficial for less-experienced endoscopists.

Superelastic effect in polycrystalline ferrous alloys

In superelastic alloys, large deformation can revert to a memorized shape after removing the stress. However, the stress increases with increasing temperature, which limits the practical use over a wide temperature range. Polycrystalline Fe-Mn-Al-Ni shape memory alloys show a small temperature dependence of the superelastic stress because of a small transformation entropy change brought about by a magnetic contribution to the Gibbs energies. For one alloy composition, the superelastic stress varies by 0.53 megapascal/°C over a temperature range from -196 to 240°C.

Relationship of intake of plant-based foods with 6-n-propylthiouracil sensitivity and food neophobia in Japanese preschool children

BACKGROUND/OBJECTIVES

Diets rich in plant-based foods such as vegetables, fruits and soy foods have been suggested to have beneficial effects on health. However, phytochemicals contained in plant-based foods are generally bitter and acrid. We investigated whether intake of vegetables, fruits and soy foods is associated with sensitivity to bitterness and reluctance to eat new foods (food neophobia) in Japanese preschool children.

SUBJECTS/METHODS

Subjects of this cross-sectional study were healthy Japanese, 167 boys and 156 girls, aged 4-6 years. Intake of vegetables, fruits and soy foods was estimated from 3-day dietary records. Subjects were classified as either tasters or non-tasters of 6-n-propylthiouracil (PROP) based on their ability to taste 0.56 mmol/l PROP. Information on each child's age, height, weight, food neophobia status and food variety, as well as maternal diet and parental control over the child's eating, was obtained by a parent-administered questionnaire. Food neophobia was assessed using the Child Food Neophobia Scale (CFNS).

RESULTS

A high intake of vegetables was significantly associated with a low CFNS score in boys after controlling for covariates (P=0.0008). Among the boys, soy food intake was significantly higher in PROP non-tasters than in tasters, except those with low CFNS scores (P=0.0019). High intake of soy foods was significantly associated with a low neophobia score in PROP tasters but not in non-tasters (P=0.0024).

CONCLUSIONS

These data suggest that sensitivity to bitter taste and food neophobia may influence the consumption of vegetables and soy foods among Japanese preschool boys.