Intraoperative Changes in Idiopathic Macular Holes by Spectral-Domain Optical Coherence Tomography

Purpose: To examine anatomical changes in idiopathic macular holes during surgery using handheld spectral-domain optical coherence tomography (SD-OCT). Methods: Five eyes of 5 patients who underwent surgery for the repair of idiopathic macular holes were examined. The surgery included standard 25-gauge, 3-port pars plana vitrectomy, removal of the internal limiting membrane (ILM), fluid-air exchange, and 20% sulfur hexafluoride tamponade. Intraoperative SD-OCT images of the macular holes were obtained after ILM removal and under fluid-air exchange using a handheld SD-OCT. From SD-OCT images, the macular hole base diameter (MHBD) was measured and compared. Results: All macular holes were successfully closed after the primary surgery. The mean MHBD under fluid-air exchange was significantly smaller than the mean MHBD after ILM removal and the preoperative mean MHBD. In 1 eye with a stage 3 macular hole, SD-OCT images revealed that the inner edges of the macular hole touched each other under fluid-air exchange. Conclusion: Fluid-air exchange significantly reduced MHBD during surgery to repair macular holes. Fluid-air exchange may be an important step for macular hole closure as it reduces the base diameter of the macular hole

Magnetoelectric switching of perpendicular exchange bias in Pt/Co/α-Cr₂O₃/Pt stacked films

We report the realization of magnetoelectric switching of the perpendicular exchange bias in Pt/Co/α-Cr₂O₃/Pt stacked films. The perpendicular exchange bias was switched isothermally by the simultaneous application of magnetic and electric fields. The threshold electric field required to switch the perpendicular exchange bias was found to be inversely proportional to the magnetic field, which confirmed the magnetoelectric mechanism of the process. The observed temperature dependence of the threshold electric field suggested that the energy barrier of the antiferromagnetic spin reversal was significantly lower than that assuming the coherent rotation. Pulse voltage measurements indicated that the antiferromagnetic domain propagation dominates the switching process. These results suggest an analogy of the electric-field-induced magnetization with a simple ferromagnet.Kentaro Toyoki, Yu Shiratsuchi, Atsushi Kobane, Chiharu Mitsumata, Yoshinori Kotani, Tetsuya Nakamura, and Ryoichi Nakatani, Appl. Phys. Lett. 106, 162404 (2015); https://doi.org/10.1063/1.4918940

Robust magnetic domain of Pt/Co/Au/Cr₂O₃/Pt stacked films with a perpendicular exchange bias

Magnetic domain pattern and magnetic domain wall motion are particularly important to understand the magnetization process. Here, we investigated the magnetization process of perpendicularly exchange-biased Pt/Co/Au/Cr₂O₃/Pt stacked films based on observations of the magnetic domain. In particular, in contrast to previous studies which use fully exchange-biased state, we used the bi-exchange-biased state. We found that the magnetic domain pattern at the remanent state was robust against magnetic-field cycling, which is relevant to the absence of the training effect. The magnetization process was followed by domain wall propagation in the increasing branch of the magnetization curve. In the decreasing branch, both nucleation of the reversed domain and domain wall propagation were involved. The former was accompanied by latency, suggesting that thermal activation played a significant role in the nucleation of the reversed domain.Yu Shiratsuchi, Saori Yoshida, Hiroaki Yoshida, Yoshinori Kotani, Kentaro Toyoki, Ryoichi Nakatani, Chiharu Mitsumata, and Tetsuya Nakamura, Journal of Applied Physics 127, 153902 (2020); https://doi.org/10.1063/5.0002240

Isothermal switching of perpendicular exchange bias by pulsed high magnetic field

Isothermal switching of a perpendicular exchange bias by a strong pulsed magnetic field has been investigated using a Pt/Co/α-Cr₂O₃ thin film system. The switching of the perpendicular exchange bias is accompanied by the spin reversal of interfacial uncompensated antiferromagnetic Cr spins. We have also demonstrated that the switching of the exchange bias is reversible by changing the pulsed magnetic field direction. The mechanism of the demonstrated switching is discussed from the viewpoint of the spin flop transition of the α-Cr₂O₃ layer.Yu Shiratsuchi, Kohei Wakatsu, Tetsuya Nakamura, Hiroto Oikawa, Satoru Maenou, Yasuo Narumi, Kou Tazoe, Chiharu Mitsumata, Toyohiko Kinoshita, Hiroyuki Nojiri, and Ryoichi Nakatani, Appl. Phys. Lett. 100, 262413 (2012); https://doi.org/10.1063/1.4731643

Abnormal Cystatin C Levels in Two Patients with Bardet-Biedl Syndrome

Bardet-Biedl syndrome (BBS) is an autosomal recessive disorder characterized by central obesity, mental impairment, rod-cone dystrophy, polydactyly, hypogonadism in males, and renal abnormalities. The causative genes have been identified as BBS1-14. In the Western countries, the prevalence of this disease ranges from 1/13,500 to 1/160,000, while only a few Japanese patients have been reported in the English-language literature. The incidence of renal dysfunction or anomalies in previous reports varies considerably ranging from ∼20% to universal occurrence. We here report that two Japanese patients who had BBS with normal BUN and creatinine levels had elevated levels of cystatin C, a sensitive marker of glomerular filtration rate. A urine albumin level increased only in the elder patient. Thus, cystatin C may be useful for detecting renal abnormalities in patients with an apparent normal renal function. Because this disease is diagnosed by accumulation of symptoms, such a sensitive marker might help early diagnosis of BBS

Structural dynamics of cereal mitochondrial genomes as revealed by complete nucleotide sequencing of the wheat mitochondrial genome

The application of a new gene-based strategy for sequencing the wheat mitochondrial genome shows its structure to be a 452 528 bp circular molecule, and provides nucleotide-level evidence of intra-molecular recombination. Single, reciprocal and double recombinant products, and the nucleotide sequences of the repeats that mediate their formation have been identified. The genome has 55 genes with exons, including 35 protein-coding, 3 rRNA and 17 tRNA genes. Nucleotide sequences of seven wheat genes have been determined here for the first time. Nine genes have an exon–intron structure. Gene amplification responsible for the production of multicopy mitochondrial genes, in general, is species-specific, suggesting the recent origin of these genes. About 16, 17, 15, 3.0 and 0.2% of wheat mitochondrial DNA (mtDNA) may be of genic (including introns), open reading frame, repetitive sequence, chloroplast and retro-element origin, respectively. The gene order of the wheat mitochondrial gene map shows little synteny to the rice and maize maps, indicative that thorough gene shuffling occurred during speciation. Almost all unique mtDNA sequences of wheat, as compared with rice and maize mtDNAs, are redundant DNA. Features of the gene-based strategy are discussed, and a mechanistic model of mitochondrial gene amplification is proposed

在宅看護実習における看護実践能力の修得状況-計量テキスト分析による検討-

departmental bulletin pape

Genetic and antigenic characterisation of influenza A(H3N2) viruses isolated in Yokohama during the 2016/17 and 2017/18 influenza seasons.

BACKGROUND: Influenza A(H3N2) virus rapidly evolves to evade human immune responses, resulting in changes in the antigenicity of haemagglutinin (HA). Therefore, continuous genetic and antigenic analyses of A(H3N2) virus are necessary to detect antigenic mutants as quickly as possible. AIM: We attempted to phylogenetically and antigenically capture the epidemic trend of A(H3N2) virus infection in Yokohama, Japan during the 2016/17 and 2017/18 influenza seasons. METHODS: We determined the HA sequences of A(H3N2) viruses detected in Yokohama, Japan during the 2016/17 and 2017/18 influenza seasons to identify amino acid substitutions and the loss or gain of potential N-glycosylation sites in HA, both of which potentially affect the antigenicity of HA. We also examined the antigenicity of isolates using ferret antisera obtained from experimentally infected ferrets. RESULTS: Influenza A(H3N2) viruses belonging to six clades (clades 3C.2A1, 3C.2A1a, 3C.2A1b, 3C.2A2, 3C.2A3 and 3C.2A4) were detected during the 2016/17 influenza season, whereas viruses belonging to two clades (clades 3C.2A1b and 3C.2A2) dominated during the 2017/18 influenza season. The isolates in clades 3C.2A1a and 3C.2A3 lost one N-linked glycosylation site in HA relative to other clades. Antigenic analysis revealed antigenic differences among clades, especially clade 3C.2A2 and 3C.2A4 viruses, which showed distinct antigenic differences from each other and from other clades in the antigenic map. CONCLUSION: Multiple clades, some of which differed antigenically from others, co-circulated in Yokohama, Japan during the 2016/17 and 2017/18 influenza seasons

Effect of Phosphatidylserine and Cholesterol on Membrane-mediated Fibril Formation by the N-terminal Amyloidogenic Fragment of Apolipoprotein A-I

Here, we examined the effects of phosphatidylserine (PS) and cholesterol on the fibril-forming properties of the N-terminal 1‒83 fragment of an amyloidogenic G26R variant of apoA-I bound to small unilamellar vesicles. A thioflavin T fluorescence assay together with microscopic observations showed that PS significantly retards the nucleation step in fibril formation by apoA-I 1‒83/G26R, whereas cholesterol slightly enhances fibril formation. Circular dichroism analyses demonstrated that PS facilitates a structural transition from random coil to α-helix in apoA-I 1‒83/G26R with great stabilization of the α-helical structure upon lipid binding. Isothermal titration calorimetry measurements revealed that PS induces a marked increase in capacity for binding of apoA-I 1‒83/G26R to the membrane surface, perhaps due to electrostatic interactions of positively charged amino acids in apoA-I with PS. Such effects of PS to enhance lipid interactions and inhibit fibril formation of apoA-I were also observed for the amyloidogenic region-containing apoA-I 8‒33/G26R peptide. Fluorescence measurements using environment-sensitive probes indicated that PS induces a more solvent-exposed, membrane-bound conformation in the amyloidogenic region of apoA-I without affecting membrane fluidity. Since cell membranes have highly heterogeneous lipid compositions, our findings may provide a molecular basis for the preferential deposition of apoA-I amyloid fibrils in tissues and organs