Okayama University
  • Okayama, Japan
Recent publications
Magnetic nanoparticles (MNPs) have been studied for various medical applications by taking advantage of their unique magnetic properties. Magnetic immunoassay (MIA) is a technique for the rapid detection of target biomarkers by antigen-antibody reaction between antibody-modified MNPs and the target biomarker. In this study, we aim to improve the accuracy of the MIA, we evaluated the AC magnetic properties of MNPs in the biological solvents. To measure the magnetic signal of MNPs, we used the developed HTS-SQUID magnetic immunoassay system. First, we evaluated the instability of the HTS-SQUID magnetic immunoassay system using pellets of manganese (II) fluoride. The results show that the device instability due to operating time does not affect the measurement of magnetic signal changes in MNPs due to biological solvents. Since the magnetic properties of MNPs depend on particle size and viscosity, we measured the time evolution of the magnetic signal of Resovist in glycerin, human serum, sheep whole blood, and NaCl. It was found that the magnetic signal of Resovist decreased exponentially with ions contained in the solvent. The results are fitted as the exponential double function, suggesting that the magnetic signal of MNPs in biological solvents is affected by the aggregation of MNPs in the blood and that there are at least two steps in the mechanism of the aggregation.
We proposed a large-capacity wireless power transmission (WPT) system for the electric vehicle in which a high-temperature superconducting (HTS) coil is installed only on the ground side. On the other hand, the design guideline of the 100 kW class WPT system using the HTS and the copper coils for EVs has not been sufficiently discussed. Therefore, we analyzed the electric power transmission characteristics of the 100 kW class proposed WPT system using the HTS coil and the copper coil by an electromagnetic field analysis using the finite element method (FEM) and an equivalent circuit analysis. Also, we investigated the effect of a cooling temperature of the HTS coil on the receiving power and the transmission efficiency of the proposed WPT system for EVs. As a result, we found that the proposed WPT systems using the high-inductance primary and secondary coils are suitable for a low-frequency operation around 1 kHz. On the other hand, the proposed WPT systems with high-frequency operation above 10 kHz are suitable for reducing the weight of the secondary coil. In addition, although the system efficiency considering the cryocooler power loss is reduced by decreasing an operating temperature of the primary HTS coil, it is possible to realize a large-capacity WPT system with the receiving power of more than 100 kW.</p
Passive smoking is associated with the risk of decreased respiratory function as well as the onset and severity of asthma in children. It is also associated with elevated total IgE levels and sensitization to food and inhalant allergens. Maternal smoking during pregnancy negatively affects fetal lung development and leads to decreased respiratory function after birth. In addition, it elevates the risks of decreased respiratory function and severe asthma in school-aged children. Passive smoking in pregnant women reduces the number of regulatory T cells in umbilical cord blood by epigenetic mechanisms, thus increasing the risk of atopic dermatitis, allergen sensitization, and wheezing during infancy. Evidence indicates that passive smoking increases disease risk due to exposure to tobacco smoke, and any interventions that legislate prevention of passive smoking decrease disease risk. Notably, the current global standard is that people are protected by legislations with penalties that were established based on the WHO Framework Convention on Tobacco Control (FCTC), which bans smoking in all public places. The risk of allergic diseases caused by passive smoking can be prevented or reduced by achieving the goals of the FCTC and maintaining an appropriate smoke-free environment consistently from the fetal period to adulthood.
All life on Earth contains amino acids and carbonaceous chondrite meteorites have been suggested as their source at the origin of life on Earth. While many meteoritic amino acids are considered indigenous, deciphering the extent of terrestrial contamination remains an issue. The Ryugu asteroid fragments (JAXA Hayabusa2 mission), represent the most uncontaminated primitive extraterrestrial material available. Here, the concentrations of amino acids from two particles from different touchdown sites (TD1 and TD2) are reported. The concentrations show that N,N-dimethylglycine (DMG) is the most abundant amino acid in the TD1 particle, but below detection limit in the other. The TD1 particle mineral components indicate it experienced more aqueous alteration. Furthermore, the relationships between the amino acids and the geochemistry suggest that DMG formed on the Ryugu progenitor body during aqueous alteration. The findings highlight the importance of aqueous chemistry for defining the ultimate concentrations of amino acids in primitive extraterrestrial samples.
Dexmedetomidine (DEX) can reduce lung injury in a hemorrhagic shock (HS) resuscitation (HSR) model in rats by inhibiting inflammation. Here, we aimed to investigate if these effects of DEX are due to autophagy activation. Therefore, we established HSR rat models and divided them into four groups. HS was induced using a blood draw. The rats were then resuscitated by reinjecting the drawn blood and saline. The rats were sacrificed 24 h after resuscitation. Lung tissues were harvested for histopathological examination, determination of wet/dry lung weight ratio, and detection of the levels of autophagy-related marker proteins LC3, P62, Beclin-1, and the ATG12-ATG5 conjugate. The morphological findings of hematoxylin and eosin staining in lung tissues and the pulmonary wet/dry weight ratio showed that lung injury improved in HSR + DEX rats. However, chloroquine (CQ), an autophagy inhibitor, abolished this effect. Detecting the concentration of autophagy-related proteins showed that DEX administration increased LC3, ATG12-ATG5, and Beclin-1 expression and decreased P62 expression. The expression levels of these proteins were similar to those in the HSR group after CQ + DEX administration. In summary, DEX induced autophagic activation in an HSR model. These findings suggest that DEX administration partially ameliorates HSR-induced lung injury via autophagic activation.
The first intermolecular enantioselective addition of nitroalkanes to unactivated α,β-unsaturated esters is described, catalyzed by a bifunctional iminophosphorane (BIMP) superbase. This fundamental synthetically relevant transformation proceeds with high enantiomeric excesses and yields over a wide range of feedstock substrates, providing pharmaceutically relevant building blocks in a single step.
Background The present retrospective study was carried out to determine the incidence of unrecognized cardiac surgery-associated acute kidney injury (CSA-AKI) due to infrequency of serum creatinine (SCr) measurements in pediatric cardiac patients and to assess the association between unrecognized CSA-AKI and clinical outcomes.Methods This study was a single-center, retrospective study of pediatric patients who underwent cardiac surgery. Patients were diagnosed with CSA-AKI based on SCr measurements, and unrecognized CSA-AKI was defined under the assumptions that there had been only one or two SCr measurements within 48 h after surgery: CSA-AKI unrecognized by one SCr measurement (AKI-URone), CSA-AKI unrecognized by two SCr measurements (AKI-URtwo), and CSA-AKI recognized by one and two SCr measurements (AKI-R). The change of SCr from baseline to postoperative day 30 (delta SCr30d) was assessed as a surrogate of kidney recovery.ResultsIn a total of 557 cases, 313 patients (56.2%) were diagnosed with CSA-AKI, 188 (33.8%) of whom had unrecognized CSA-AKI. Delta SCr30d in the AKI-URtwo group and delta SCr30d in the AKI-URone group was not significantly different from delta SCr30d in the non-AKI group (p = 0.67 and p = 0.79, respectively). There were significant differences in the durations of mechanical ventilation, serum B-type natriuretic peptide levels, and lengths of stay in hospital between the non-AKI group and the AKI-URtwo group and between the non-AKI group and the AKI-URtwo group.Conclusions Unrecognized CSA-AKI due to infrequent SCr measurements is not rare and is associated with prolonged mechanical ventilation, high postoperative BNP level, and prolonged length of stay in hospital.Graphical abstract A higher resolution version of the Graphical abstract is available as Supplementary information
Adenosylcobalamin (AdoCbl) or coenzyme B12 is a naturally occurring organometallic compound that serves as a cofactor for enzymes that catalyze intramolecular group-transfer reactions and ribonucleotide reduction in a wide variety of organisms from bacteria to animals. AdoCbl-dependent enzymes are radical enzymes and generate an adenosyl radical by homolysis of the coenzyme's cobalt-carbon (Co-C) bond for catalysis. How do the enzymes activate and cleave the Co-C bond to form the adenosyl radical? How do the enzymes utilize the high reactivity of adenosyl radical for catalysis by suppressing undesirable side reactions? Our recent structural studies aimed to solve these problems with diol dehydratase and ethanolamine ammonia-lyase established the crucial importance of steric strain of the Co-C bond and conformational stabilization of adenosyl radical for coenzyme B12 catalysis. We outline here our results obtained with these eliminating isomerases and compare them with those obtained with other radical B12 enzymes.
Teleost fishes exhibit complex sexual characteristics in response to androgens, such as fin enlargement and courtship display. However, the molecular mechanisms underlying their evolutionary acquisition remain largely unknown. To address this question, we analyse medaka (Oryzias latipes) mutants deficient in teleost-specific androgen receptor ohnologs (ara and arb). We discovered that neither ar ohnolog was required for spermatogenesis, whilst they appear to be functionally redundant for the courtship display in males. However, both were required for reproductive success: ara for tooth enlargement and the reproductive behaviour eliciting female receptivity, arb for male-specific fin morphogenesis and sexual motivation. We further showed that differences between the two ar ohnologs in their transcription, cellular localisation of their encoded proteins, and their downstream genetic programmes could be responsible for the phenotypic diversity between the ara and arb mutants. These findings suggest that the ar ohnologs have diverged in two ways: first, through the loss of their roles in spermatogenesis and second, through gene duplication followed by functional differentiation that has likely resolved the pleiotropic roles derived from their ancestral gene. Thus, our results provide insights into how genome duplication impacts the massive diversification of sexual characteristics in the teleost lineage.
Aim: To characterize extensively drug-resistant Pseudomonas aeruginosa from a patient with diarrhea. Materials & methods: Antimicrobial susceptibility was tested by the disk diffusion method. The P. aeruginosa genome was sequenced to identify virulence, antibiotic resistance and prophages encoding genes. Results: P. aeruginosa had a wide spectrum of resistance to antibiotics. Genomic analysis of P. aeruginosa revealed 76 genes associated with antimicrobial resistance, xenobiotic degradation and the type three secretion system. Conclusion: This is the first report on diarrhea associated with P. aeruginosa. Since no other organism was identified, the authors assume that the patient had dysbiosis due to antibiotic exposure, leading to antibiotic-associated diarrhea. The in vivo toxicity expressed by the pathogen may be associated with T3SS.
Background: Myxedema coma is an extremely rare but fatal endocrine emergency that requires urgent recognition and treatment. We describe a case of severe hypothermia that rapidly deteriorated to cardiac arrest that was attributed to myxedema coma. Case presentation: A 52-year-old man without a history of hypothyroidism was transferred to our emergency department due to coma and profound hypothermia. The patient developed cardiac arrest immediately after hospital arrival but return of spontaneous circulation was achieved shortly after resuscitation. The patient was noted to have generalized, nonpitting edema, dry skin, severe respiratory acidosis, hyponatremia, and elevated creatinine kinase, which was indicative of hypothyroidism. Myxedema coma was confirmed by a thyroid profile. The patient was successfully treated with intravenous levothyroxine and glucocorticoid. Conclusion: Although myxedema coma is a rare cause of severe hypothermia, emergency physicians should be familiar with its clinical features and management.
BACKGROUND Endovascular treatment is the mainstay of treatment for carotid-cavernous fistulas, but endovascular approaches vary widely. The authors report a rare case of a direct carotid-cavernous fistula with cranial nerve symptoms caused by rupture of a giant aneurysm in which selective transvenous embolization via the pterygoid plexus was performed. OBSERVATIONS An 81-year-old man presented with headache and various progressive cranial nerve symptoms due to a direct carotid-cavernous fistula caused by a ruptured giant aneurysm. All the draining veins visualized on preoperative examination immediately before the treatment were occluded except for the pterygoid plexus. Therefore, the authors chose the dilated pterygoid plexus to approach the shunted pouch at the cavernous sinus and achieve shunt obliteration by selective embolization with coils and n-butyl cyanoacrylate. LESSONS Careful study of the three-dimensional rotational images in the preoperative examination is important when considering the various approaches to surgery. The pterygoid plexus can be an effective venous approach route to reach the cavernous sinus area.
Millimeter wave absorption exceeding 70 GHz has been performed in a Co-substituted Ca–La magnetoplumbite (M-type) ferrite. A polymerized complex method was used to increase the substitution of La and Co ions in the M-type ferrite. The increase in the magnetic anisotropy field combined with the remaining significant saturation magnetization results in good magnetic resonance absorption in the millimeter range of 70–100 GHz. Above 70 GHz, good millimeter wave absorption of more than −20 dB was achieved in 0.25 mm thickness plates of Ca 0.46 La 0.54 Fe 11 Co 0.28 O 19‐η and Ca 0.42 La 0.58 Fe 11 Co 0.58 O 19‐η . Highly Co-substituted Ca–La M-type ferrites may, thus, be promising candidates for magnetic absorption materials operating in frequencies of up to 100 GHz.
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1,979 members
Nahoko Harada
  • Faculty of Interdisciplinary Science and Engineering in Health Systems
Takeshi Hiyama
  • Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences
Tsutomu Nohno
  • Department of Cytology and Histology
Muzembo Basilua Andre
  • Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences
Sayaka Aizawa
  • Department of Biology
Okayama, Japan