Biomedical subjects

Satoshi Watanabe

Publications and source records attributed to Satoshi Watanabe.

At least 37 records · Page 2Linked to original sources

PubMed2006

Rice plants take up iron as an Fe3+-phytosiderophore and as Fe2+.

Only graminaceous monocots possess the Strategy II iron (Fe)-uptake system in which Fe is absorbed by roots as an Fe3+-phytosiderophore. In spite of being a Strategy II plant, however, rice (Oryza sativa) contains the previously identified Fe2+ transporter OsIRT1. In this study, we isolated the OsIRT2 gene from rice, which is highly homologous to OsIRT1. Real-time PCR analysis revealed that OsIRT1 and OsIRT2 are expressed predominantly in roots, and these transporters are induced by low-Fe conditions. When expressed in yeast (Saccharomyces cerevisiae) cells, OsIRT2 cDNA reversed the growth defects of a yeast Fe-uptake mutant. This was similar to the effect of OsIRT1 cDNA. OsIRT1- and OsIRT2-green fluorescent protein fusion proteins localized to the plasma membrane when transiently expressed in onion (Allium cepa L.) epidermal cells. OsIRT1 promoter-GUS analysis revealed that OsIRT1 is expressed in the epidermis and exodermis of the elongating zone and in the inner layer of the cortex of the mature zone of Fe-deficient roots. OsIRT1 expression was also detected in the ccompanion cells. Analysis using the positron-emitting tracer imaging system showed that rice plants are able to take up both an Fe3+-phytosiderophore and Fe2+. This result indicates that, in addition to absorbing an Fe3+-phytosiderophore, rice possesses a novel Fe-uptake system that directly absorbs the Fe2+, a strategy that is advantageous for growth in submerged conditions.

Amino Acid Sequence↗

PubMed2006

Biosynthesis and secretion of mugineic acid family phytosiderophores in zinc-deficient barley.

Mugineic acid family phytosiderophores (MAs) are metal chelators that are produced in graminaceous plants in response to iron (Fe) deficiency, but current evidence regarding secretion of MAs during zinc (Zn) deficiency is contradictory. Our studies using HPLC analysis showed that Zn deficiency induces the synthesis and secretion of MAs in barley plants. The levels of the HvNAS1, HvNAAT-A, HvNAAT-B, HvIDS2 and HvIDS3 transcripts, which encode the enzymes involved in the synthesis of MAs, were increased in Zn-deficient roots. Studies of the genes involved in the methionine cycle using microarray analysis showed that the transcripts of these genes were increased in both Zn-deficient and Fe-deficient barley roots, probably allowing the plant to meet its demand for methionine, a precursor in the synthesis of MAs. In addition, HvNAAT-B transcripts were detected in Zn-deficient shoots, but not in those that were deficient in Fe. Increased synthesis of MAs in Zn-deficient barley was not due to a deficiency of Fe, because Zn-deficient barley accumulated more Fe than did the control plants, ferritin transcripts were increased in Zn-deficient plants, and Zn deficiency promoted Fe transport from root to shoot. Moreover, analysis using the positron-emitting tracer imaging system (PETIS) confirmed that more 62Zn(II)-MAs than 62Zn2+ were absorbed by the roots of Zn-deficient barley plants. These data suggest that the increased biosynthesis and secretion of MAs arising from a shortage of Zn are not due to an induced Fe deficiency, and that secreted MAs are effective in absorbing Zn from the soil.

Azetidinecarboxylic Acid↗

PubMed2006

Influence of autonomic nervous dysfunction characterizing effect of diabetes mellitus on heart rate response and exercise capacity in patients undergoing cardiac rehabilitation for acute myocardial infarction.

BACKGROUND: The aim of this study was to clarify the influence of sympathetic and parasympathetic nerve (SN and PN) dysfunction on the heart rate (HR) response to exercise and the exercise capacity of patients with acute myocardial infarction (AMI) and diabetes mellitus (DM). METHODS AND RESULTS: Fifty-two male patients who underwent cardiopulmonary exercise testing (CPX) 1 month after onset of AMI were divided into 2 groups: (DM (+) group, n=20; DM (-) group, n=32). HR, peak oxygen uptake (VO2peak), and plasma norepinephrine (NE) levels were measured during CPX. The high-frequency power (HF) was analyzed by HR variability. The DeltaHR/logDeltaNE obtained from changes of HR and NE from rest to peak exercise and HR change from baseline to the minimum HF (DeltaHRHF) were calculated as parameters of HR response derived from SN and PN activities, respectively. DeltaHR, VO2peak, DeltaHR/logDeltaNE, and DeltaHRHF were significantly lower in the DM (+) group than in the DM (-) group, and both of them showed positive correlations with VO2peak. CONCLUSION: An inadequate HR response to exercise is a major factor causing a decline of exercise capacity, which is derived from both of SN and PN dysfunction, in AMI patients with DM.

Autonomic Nervous System↗

PubMed2006

Impedance cardiography for cardiac output estimation: reliability of wrist-to-ankle electrode configuration.

BACKGROUND: Non-invasive measurement of cardiac output (CO) may become an important modality for the treatment of heart failure. Among the several methods proposed, impedance cardiography (ICG) has gained particular attention. There are 2 basic technologies of ICG: thoracic and whole-body ICG whereby the electrodes are applied either to the chest or to the limbs. The present study is aimed to test the effectiveness of the Non-Invasive Cardiac System (NICaS), a new ICG device working with a wrist-to-ankle configuration. METHODS AND RESULTS: To evaluate the reliability of NICaS derived CO (NI-CO), 50 CO measurements were taken simultaneously with thermodilution (TD-CO) and modified Fick (Fick-CO) in 35 cardiac patients, with the TD-CO serving as the gold-standard for the evaluation. Overall, 2-tailed Pearson's correlation and Bland-Altman limits of agreement between NI-CO and TD-CO were r=0.91 and -1.06 and 0.68 L/min and between Fick-CO and TD-CO, r=0.80 and -1.52 and 0.88 L/min, respectively. Good correlation was observed in patients with loading conditions altered by nitroglycerin and also in patients with moderate valvular diseases. CONCLUSION: Agreement between NI-CO and TD-CO is within the boundaries of the FDA guidelines of bio-equivalence. NI-CO is applicable for non-invasive assessment of cardiac function.

Aged↗

PubMed2006

Persistent malapposition after implantation of sirolimus-eluting stent into intramural coronary hematoma: optical coherence tomography observations.

A 76-year-old man presented with an anterior myocardial infarction. Coronary angiography showed 99% stenosis in the left anterior descending artery and total occlusion in the left circumflex artery (LCX). After successful percutaneus coronary intervention (PCI) for segment 7, a staged PCI to the LCX with a distal protection system was attempted, but the wire entered the subintima, creating a large dissection and intramural hematoma. Three sirolimus-eluting stents (SES) were implanted to cover the entire hematoma, but 2 weeks later intravascular ultrasound revealed stent malapposition, with healing of the residual hematoma, and vessel enlargement. Optical coherence tomography (OCT) showed the malapposition more clearly. Balloon dilatation successfully achieved apposition of the SES to the vessel wall, but 6 months later it revealed recurrence of malapposition, with the struts covered by thrombus-like tissue. This case suggests that SES implantation treatment of a long intramural hematoma can potentially cause late malapposition because of persistent vessel enlargement related to arterial wall injury and inhibition of neointimal hyperplasia by the SES. OCT is useful in showing the precise condition of the stent struts.

Aged↗

PubMed2006

N-terminal mutational analysis of the interaction between growth-blocking peptide (GBP) and receptor of insect immune cells.

GBP, a small insect cytokine isolated from lepidopterans, has a variety of functions. We constructed a series of mutants focusing on the unstructured N-terminal residues of GBP by acetylation, deletion, and elongation in order to investigate the interaction between GBP and its receptor in plasmatocytes. The 1H NMR spectra showed no significant changes in the tertiary structures of these peptides, which indicated that all the mutants maintained their core beta-sheet structures. The deletion and acetylated mutants, 2-25GBP, Ac2-25GBP, and AcGBP, lost their activity. 2-25GBP was the strongest antagonist, while Ac2-25GBP and AcGBP were moderate. In contrast, the elongated mutants, (-1R)GBP, (-1A)GBP, and (-2G,-1R)GBP maintained their plasmatocyte-spreading activity. These results demonstrate the importance of the GBP N-terminal charged amine and length of N-terminal GBP-peptide backbone for plasmatocyte-spreading activity. Next, we analyzed other mutant peptides, 1-25(N2A)GBP and 2-25(N2A)GBP, focusing on Asn2. Surprisingly, 2-25(N2A)GBP had slight plasmatocyte-spreading activity, whereas 2-25GBP lost its activity. Finally, substituted mutant, F3AGBP, had neither plasmatocyte-spreading activity nor antagonistic activity. These results demonstrate the function of each N-terminal residue in the interaction between GBP and its receptor in plasmatocytes.

Amino Acid Sequence↗

PubMed2006

[Invasive diagnostic technique and technology for heart failure].

Technology and techniques of cardiac catheterization to assess the ventricular function have been developed in the recent decades. The approach for assessing function is based on the measurement of cardiac output which depends on preload, afterload and ventricular contractility. Clinical application of Frank-Starling principle is useful for characterizing human heart failure. Conventionally, the isovolumic phase index(peak positive dP/dt) and ejection phase index (ejection fraction) have been applied to evaluate ventricular systolic function. Recently, ventricular diastolic function as well as systolic function can be estimated using ventricular pressure-volume loops obtained by simultaneous measurement of pressure and volume. The slope of end-systolic pressure-volume relation represents a load-independent index of ventricular contractility and assessing ventricular end-diastolic pressure-volume relation can express ventricular passive diastolic compliance for the evaluation of human heart failure.

Cardiac Catheterization↗

PubMed2006

[Estimation of time of death by the use of the overwintering of flies].

We observed whether or not there were eggs, larvae, pupae, and empty pupal shells of flies on cadavers found outdoors in Sapporo, the northern district of Japan (43 degrees N). The temperature has an influence on the oviposition of flies. The average season in which flies lay eggs is from the middle of April to the beginning of November, although there is a little lag year by year. As flies overwinter generally as larvae, we can estimate postmortem interval of a cadaver found in spring on the basis of the size and the mortality of the larvae. If the length of larvae is 1 cm or longer, and many of them are dead, and if there are no empty pupal shells, the time of death of a cadaver found outdoors in spring is between the middle of September and the beginning of November in the previous year.

Animals↗

PubMed2006

[Relationship between high sensitive C-reactive protein and coronary plaque component in patients with acute coronary syndrome: Virtual Histology study].

OBJECTIVES: Elevated circulating C-reactive protein (CRP)is commonly observed in patients with acute coronary syndrome(ACS), suggesting enhanced inflammation in vulnerable plaques. However, few data are available on the relationship between the levels of CRP and the histological composition of coronary plaque. We investigated the relationship between plasma high sensitive CRP level and coronary plaque component with Virtual Histology intravascular ultrasound (VH-IVUS). METHODS: Twenty eight patients with ACS and 37 patients with non-ACS were enrolled in the study. Plasma high sensitve CRP levels were measured before catheterization. A total of 125 lesions (ACS; 24 culprit lesions, 30 non-culprit lesions, non-ACS; 34 culprit lesions, 37 non-culprit lesions)underwent IVUS volumetric investigation, and the volume of plaque and media were calculated. Spectral analysis of IVUS radiofrequency data was performed with VH software, and plaque and media were classified into fibrous, fibro-fatty, dense calcium, and necrotic core elements. RESULTS: Although the plasma high sensitive CRP level in patients with ACS was higher than that in those with non-ACS (0.26 +/- 0.2 vs 0.15 +/- 0.17 mg/dl, p < 0.05), necrotic core volume was not different between the two groups(11.7 +/- 7.3 vs 12.3 +/- 7.2mm3/cm, p = 0.71). There was a positive correlation between high sensitve CRP and necrotic core volume in patients with ACS, not only in culprit lesions (p = 0.0004, r2 = 0.564) but also in non-culprit lesions (p = 0.0008, r2 = 0.473), whereas patients with non-ACS showed no correlations. CONCLUSIONS: IVUS spectral analysis revealed that elevated plasma high sensitve CRP level was correlated with necrotic core volume in patients with ACS, both in culprit and non-culprit lesions, suggesting enhanced vascular inflammation.

Acute Disease↗

PubMed2006

[Problems in applying a rapid assay kit for cardiac troponin T to medico-legal blood samples].

It is difficult to diagnose cardiac-related death only by external examination. However, in the areas where no medical examiner system is established, the diagnosis is made mostly from the findings by external examination. Clinically, cardiac troponin T (cTnT) rapid assay kits are used for the diagnosis of ischemic heart disease. The kits have started being applied to forensic medicine and used for the diagnosis of cardiac-related death without exact evidence. In this study, we collected postmortem blood samples from 110 forensic autopsy cases and evaluated the utility of the kits in the field of forensic medicine. Blood samples collected from the left and the right parts of the hearts showed extremely high positive rates (95.1% each), and peripheral blood samples also showed very high positive rates (71.2%), although cardiac-related deaths were only 7 cases of all 110 cases. Because cTnT concentration of postmortem blood samples is affected by non-cardiac-related natural death, postmortem changes, or cardiopulmonary resuscitation, the results from using the kits are not reliable in determining the cause of death. We conclude that the kits cannot be applied in forensic medicine.

Autopsy↗

PubMed2006

[A case of squamous cell carcinoma of unknown primary site with involvement of cervico-mediastinal lymph nodes successfully treated by chemoradiotherapy].

A 70-year-old woman was admitted with cervicomediastinal lymph node metastases from squamous cell carcinoma of unknown primary site (Sq-CUPS). The patient was treated with 4 cycles of chemotherapy combining carboplatin and paclitaxel with subsequent radiation therapy. After serial treatment, a partial response was obtained, and the disease has not recurred for over 2 years. Chemotherapy with carboplatin and paclitaxel followed by sequential radiation therapy was suggested to be potentially useful for Sq-CUPS with involvement of cervicomediastinal lymph nodes, although this group of patients is generally regarded to have a poor prognosis.

Aged↗

PubMed2005

Crystal structure of atypical cytoplasmic ABC-ATPase SufC from Thermus thermophilus HB8.

SufC, a cytoplasmic ABC-ATPase, is one of the most conserved Suf proteins. SufC forms a stable complex with SufB and SufD, and the SufBCD complex interacts with other Suf proteins in the Fe-S cluster assembly. We have determined the crystal structure of SufC from Thermus thermophilus HB8 in nucleotide-free and ADP-Mg-bound states at 1.7A and 1.9A resolution, respectively. The overall architecture of the SufC structure is similar to other ABC ATPases structures, but there are several specific motifs in SufC. Three residues following the end of the Walker B motif form a novel 3(10) helix which is not observed in other ABC ATPases. Due to the novel 3(10) helix, a conserved glutamate residue involved in ATP hydrolysis is flipped out. Although this unusual conformation is unfavorable for ATP hydrolysis, salt-bridges formed by conserved residues and a strong hydrogen-bonding network around the novel 3(10) helix suggest that the novel 3(10) helix of SufC is a rigid conserved motif. Compared to other ABC-ATPase structures, a significant displacement occurs at a linker region between the ABC alpha/beta domain and the alpha-helical domain. The linker conformation is stabilized by a hydrophobic interaction between conserved residues around the Q loop. The molecular surfaces of SufC and the C-terminal helices of SufD (PDB code: 1VH4) suggest that the unusual linker conformation conserved among SufC proteins is probably suitable for interacting with SufB and SufD.

ATP-Binding Cassette Transporters↗

PubMed2005

Electronic transport in fullerene C20 bridge assisted by molecular vibrations.

The effect of molecular vibrations on electronic transport is investigated with the smallest fullerene C20 bridge, utilizing the Keldysh nonequilibrium Green's function techniques combined with the tight-binding molecular-dynamics method. Large discontinuous steps appear in the differential conductance when the applied bias voltage matches particular vibrational energies. The magnitude of the step is found to vary considerably with the vibrational mode and to depend on the local electronic states besides the strength of electron-vibration coupling. On the basis of this finding, a novel way to control the molecular motion by adjusting the gate voltage is proposed.

Journal Article↗

PubMed2005

Input-output analysis of in vivo photoassimilate translocation using Positron-Emitting Tracer Imaging System (PETIS) data.

The Positron-Emitting Tracer Imaging System (PETIS) is introduced for monitoring the distribution of (11)C-labelled photoassimilates in Sorghum. The obtained two-dimensional image data were quantitatively analysed using a transfer function analysis approach. While one half of a Sorghum root in a split root system was treated with either 0, 100, or 500 mM NaCl dissolved in the nutrient solution, tracer images of the root halves and the lower stem section were recorded using PETIS. From the observed tracer levels, parameters were estimated, from which the mean speed of tracer transport and the proportion of tracer moved between specified image positions were deduced. Transport speed varied between 0.7 and 1.8 cm min(-1) with the difference depending on which part of the stem was involved. When data were collected in the lowest 0.5-1 cm of the stem, which included the point where the roots emerge, transport speed was less. Rapid changes in NaCl concentration, from 0 to 100 mM, resulted in short-term increases of assimilate import into the treated root. This response represented a transient osmotic effect, that was compensated for in the medium-term by osmotic adaptation. Higher concentrations of NaCl (500 mM) resulted in distinctly less photoassimilate transport into the treated root half. The present results agree with earlier observations, showing that transport of (11)C-labelled photoassimilates measured with the PETIS detector system can be quantified using the method of input-output analysis. It is worth noting that with the PETIS detector system, areas of interest do not need to be defined until after data collection. This means that unexpected behaviour of a plant organ will be seen, which is not necessarily the case with conventional detector systems looking at predefined areas of interest.

Biological Transport↗

PubMed2005

Comparative studies of the quantification of genetically modified organisms in foods processed from maize and soy using trial producing.

Seven types of processed foods, namely, cornstarch, cornmeal, corn puffs, corn chips, tofu, soy milk, and boiled beans, were trial produced from 1 and 5% (w/w) genetically modified (GM) mixed raw materials. In this report, insect resistant maize (MON810) and herbicide tolerant soy (Roundup Ready soy, 40-3-2) were used as representatives of GM maize and soy, respectively. Deoxyribonucleic acid (DNA) was extracted from the raw materials and the trial-produced processed food using two types of methods, i.e., the silica membrane method and the anion exchange method. The GM% values of these samples were quantified, and the significant differences between the raw materials and the trial-produced processed foods were statistically confirmed. There were some significant differences in the comparisons of all processed foods. However, our quantitative methods could be applied as a screening assay to tofu and soy milk because the differences in GM% between the trial-produced processed foods and their raw materials were lower than 13 and 23%, respectively. In addition, when quantitating with two primer pairs (SSIIb 3, 114 bp; SSIIb 4, 83 bp for maize and Le1n02, 118 bp; Le1n03, 89 bp for soy), which were targeted within the same taxon specific DNA sequence with different amplicon sizes, the ratios of the copy numbers of the two primer pairs (SSIIb 3/4 and Le1n02/03) decreased with time in a heat-treated processing model using an autoclave. In this report, we suggest that the degradation level of DNA in processed foods could be estimated from these ratios, and the probability of GM quantification could be experimentally predicted from the results of the trial producing.

Animals↗

PubMed2005

Dynamics of order formation by colloidal adsorption onto a substrate studied with Brownian dynamics.

Colloidal adsorption and spontaneous ordering of adsorbed particles on a substrate was simulated using a three-dimensional simulation model for colloidal dispersion system with an adsorptive surface under a specified bulk concentration, where the particle-particle and particle-substrate interactions were modeled on the DLVO theory. The key process for order formation is considered to be the adsorption of a particle that induces the transition from incomplete order to perfect order, and is found to involve a stochastic nature due to an energy barrier which must be overcome for the system to reach ordered state. Also, a model was developed to predict the energy barrier for order formation based on direct observation of the key process. Further, a model to describe the stochastic nature of the process was developed and its quantitative validity was demonstrated. Through the examination of the key process, it is concluded that the mechanism of the order formation is composed of two successive processes and the rate-determining step varies depending on the ionic strength.

Journal Article↗

PubMed2005

Fine mapping of the FT1 locus for soybean flowering time using a residual heterozygous line derived from a recombinant inbred line.

Fine-mapping of loci related to complex quantitative traits is essential for map-based cloning. A residual heterozygous line (RHL) of soybean (Glycine max) derived from a recombinant inbred line (RIL) was used for fine-mapping FT1, which is a major quantitative trait locus (QTL) responsible for soybean flowering time. The residual heterozygous line RHL1-156 was selected from the RILs that were derived from two distantly related varieties, Misuzudaizu and Moshidou Gong 503. The genome of RHL1-156 contains a heterozygous segment (approximately 17 cM) surrounding the FT1 locus but is homozygous in other regions, including three other loci affecting flowering time. A large segregating population of 1,006 individuals derived by selfing of RHL1-156 included two homozygous genotypes for the nearest marker of FT1 whose flowering time differed by 26 days. No continuous range of phenotypes was observed, in contrast to the F2 population, suggesting that a single FT1 locus affected the flowering time in the RHL1-156 line. Linkage analysis revealed that the FT1 locus mapped as a single Mendelian factor between two tightly linked DNA markers, Satt365 and GM169, at distances of approximately 0.1 cM and 0.4 cM, respectively. Our results show that a RHL derived from RILs can be used to fine-map a QTL and that RHLs can be an efficient tool for a systematic fine-mapping of QTLs.

Breeding↗

PubMed2005

A new, simple stapling technique for pulmonary emphysema: its effects and safety for improving respiratory function.

PURPOSE: We performed lung volume reduction surgery (LVRS) in an experimental model using a simple stapling technique (SST) for pulmonary emphysema. The technique uses a stapler to isolate the affected lung from the remaining lung instead of removing it. We performed the present experiment using dogs to study the effects and safety of LVRS using the SST. METHODS: Pulmonary emphysema was induced in 12 dogs with papain. They were divided into three groups: those operated on with SST composed the operation (Op) group; those receiving an experimental thoracotomy composed the sham-operation (Sham-op) group; and those not operated on composed the nonoperation (Non-op) group. Respiratory function was compared among the groups before induction of emphysema (baseline), after induction of emphysema (preoperation), and at 8 weeks after the operation (postoperation Op and Sham-op groups only). The lung was removed and histologically examined 8 weeks after the SST operation. RESULTS: In the Op group, alteration in forced expiratory volume (FEV) 0.5%, airway resistance (Raw) and specific airway conductance (sGaw) showed significantly favorable results. Histologically, the isolated area was widely replaced by fibrous tissue with numerous blood vessels in the circumference in the Op group; no signs of infection such as polykaryoleukocytes or microabscesses were observed in any of the samples. CONCLUSION: The LVRS for pulmonary emphysema using a simple stapling technique improved the expiratory flow and alleviated airway resistance. The isolated remaining lung was well organized without any infectious events or secondary adversity, thus demonstrating the safety of this technique. From these results, this technique is therefore suggested to be effective and applicable to clinical use.

Animals↗