Publications by authors named "Y Kumon"

233 Publications

Wide-field fluorescent nanodiamond spin measurements toward real-time large-area intracellular thermometry.

Sci Rep 2021 Feb 19;11(1):4248. Epub 2021 Feb 19.

Department of Chemistry, Graduate School of Science, Osaka City University, Osaka, 558-8585, Japan.

Measuring optically detected magnetic resonance (ODMR) of diamond nitrogen vacancy centers significantly depends on the photon detectors used. We study camera-based wide-field ODMR measurements to examine the performance in thermometry by comparing the results to those of the confocal-based ODMR detection. We show that the temperature sensitivity of the camera-based measurements can be as high as that of the confocal detection and that possible artifacts of the ODMR shift are produced owing to the complexity of the camera-based measurements. Although measurements from wide-field ODMR of nanodiamonds in living cells can provide temperature precisions consistent with those of confocal detection, the technique requires the integration of rapid ODMR measurement protocols for better precisions. Our results can aid the development of camera-based real-time large-area spin-based thermometry of living cells.
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http://dx.doi.org/10.1038/s41598-021-83285-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7895939PMC
February 2021

Relationship between Deep White Matter Hyperintensities on Magnetic Resonance Imaging and Postoperative Cognitive Function Following Clipping of Unruptured Intracranial Aneurysm.

Neurol Med Chir (Tokyo) 2021 Feb 30;61(2):152-161. Epub 2020 Dec 30.

Department of Neurosurgery, Ehime University Graduate School of Medicine, Toon, Ehime, Japan.

To evaluate the effects on cognitive function of deep white matter hyperintensities (DWMHs) on magnetic resonance imaging (MRI) in patients treated surgically for unruptured intracranial aneurysms (UIAs). The subjects were 106 patients in whom a Wechsler adult intelligence scale-revised (WAIS-R) examination was performed 1 week before and 1 month after clipping surgery for asymptomatic UIAs. DWMH severity was evaluated on preoperative MR images by Fazekas scale, as follows: none (absence), mild (punctate foci), moderate (beginning confluence of foci), or severe (large confluent areas). A decrease of 7 or more points in intelligence quotient (IQ) postoperatively was considered deterioration. Fazekas score was none in 41 (none group), mild in 42 (mild group), moderate in 21, and severe in 2 patients (moderate/severe group). Patient characteristics, surgical factors, IQ change, and abnormal findings on postoperative MRI were compared among the groups. Although there was no statistically significant deterioration in IQ postoperatively in any group, the percentage of deteriorated patients was significantly higher in the moderate/severe group (34.8%) than in the other groups (4.9% in the none group, 7.1% in the mild group; p <0.01, p <0.05, respectively). Brain injury was observed more frequently on postoperative MR images in the moderate/severe group (17.4%) compared with the none group (2.4%; p = 0.052). The presence of moderate/severe DWMHs was an independent prognostic factor for postoperative cognitive dysfunction. In conclusion, the presence of moderate/severe DWMHs was a prognostic factor for postoperative cognitive dysfunction after surgery for UIAs.
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http://dx.doi.org/10.2176/nmc.oa.2020-0290DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7905299PMC
February 2021

Detection of nerve enlargement with ultrasound and correlation with skin biopsy findings in painful sensory neuropathy associated with Sjögren's syndrome.

Mod Rheumatol 2021 Jul 13;31(4):849-855. Epub 2020 Oct 13.

Department of Pathology and Molecular Medicine, Hirosaki University, Hirosaki, Japan.

Objectives: We evaluated usefulness of peripheral nerve ultrasound (US) in detecting abnormality in painful sensory neuropathy (PSN) associated with primary Sjögren's syndrome (pSS), and associations among various clinical factors, US findings, and intraepidermal nerve fiber density (IENFD).

Methods: We conducted a retrospective, single-center, observational study of patients with pSS-PSN. US image was obtained to measure cross sectional area (CSA) of peripheral nerves and compared with matched pSS control.

Results: We included 11 patients with pSS-PSN (10 women; age 70.5 ± 5.66) and 17 pSS controls (15 women; age 62.5 ± 16.7). Sural nerve CSA were significantly increased in pSS-PSN group (3.48 ± 1.0 mm vs 2.05 ± 0.65 mm,  = .001). US of sural nerve showed the area under the ROC curve of 0.872 (95% CI, 0.732 - 1). Sural nerve CSA and IENFD of lower leg showed positive correlation. Compared with pSS-PSN patients with abnormal IENFD, those with normal IENFD showed significantly larger sural nerve CSA, and trends toward less systemic disease activity and small fiber impairment with sparing of large fibers.

Conclusion: US was useful in discriminating pSS patients with PSN from those without. Additionally, US may disclose distinct subsets of pSS-PSN with different clinical findings and IENFD.
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http://dx.doi.org/10.1080/14397595.2020.1830484DOI Listing
July 2021

Association of platelet response to cilostazol with clinical outcome and CYP genotype in patients with cerebral infarction.

Thromb Res 2018 12 10;172:14-20. Epub 2018 Oct 10.

Department of Hematology, Clinical Immunology, and Infectious Diseases, Ehime University Graduate School of Medicine, Japan; Department of Blood Transfusion and Cell Therapy, Ehime University Graduate School of Medicine, Japan. Electronic address:

Introduction: Cilostazol, an anti-platelet drug that inhibits phosphodiesterase 3, is beneficial for patients with atherothrombosis. In contrast to other anti-platelet drugs such as aspirin and thienopyridines, little information is available on the relationship between platelet responses to cilostazol and clinical outcomes.

Materials And Methods: We conducted a prospective study on patients with cerebral infarction who were treated with cilostazol. The platelet response to cilostazol was assessed with our new assay for the phosphorylation of vasodilator-stimulated phosphoprotein (VASP) subsequent to the pharmacological action of cilostazol. Patients were followed up for 2 years and the relationship between VASP assay results and the recurrence of thrombotic events was examined. We also investigated the effects of CYP3A5 and CYP2C19 genotypes involved in the metabolism of cilostazol on the platelet response to cilostazol.

Results: Among the 142 patients enrolled, 130 completed the 2-year follow-up and the recurrence of thrombotic events was noted in 8 (6.2%). VASP phosphorylation levels were significantly lower in patients with than in those without recurrence. The combined genotype of CYP3A5*1/*3 and CYP2C19*1/*1 was associated with a low level of VASP phosphorylation, while either genotype was not. A multivariate analysis showed that high residual platelet reactivity during the cilostazol treatment, which was defined by a low response of platelet VASP phosphorylation to cilostazol, was an independent risk factor for the recurrence of thrombotic events.

Conclusion: A low platelet response to cilostazol determined by a new platelet assay was associated with the recurrence of thrombotic events in patients with cerebral infarction.
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http://dx.doi.org/10.1016/j.thromres.2018.10.003DOI Listing
December 2018

Comparison of the detrimental features of microglia and infiltrated macrophages in traumatic brain injury: A study using a hypnotic bromovalerylurea.

Glia 2018 10 8;66(10):2158-2173. Epub 2018 Sep 8.

Department of Molecular and Cellular Physiology, Graduate School of Medicine, Ehime University, Toon, Ehime, Japan.

Microglia and blood-borne macrophages in injured or diseased brains are difficult to distinguish because they share many common characteristics. However, the identification of microglia-specific markers and the use of flow cytometry have recently made it easy to discriminate these types of cells. In this study, we analyzed the features of blood-borne macrophages, and activated and resting microglia in a rat traumatic brain injury (TBI) model. Oxidative injury was indicated in macrophages and neurons in TBI lesions by the presence of 8-hydroxy-2'-deoxyguanosine (8-OHdG). Generation of mitochondrial reactive oxygen species (ROS) was markedly observed in granulocytes and macrophages, but not in activated or resting microglia. Dihydroethidium staining supported microglia not being the major source of ROS in TBI lesions. Furthermore, macrophages expressed NADPH oxidase 2, interleukin-1β (IL-1β), and CD68 at higher levels than microglia. In contrast, microglia expressed transforming growth factor β1 (TGFβ1), interleukin-6 (IL-6), and tumor necrosis factor α at higher levels than macrophages. A hypnotic, bromovalerylurea (BU), which has anti-inflammatory effects, reduced both glycolysis and mitochondrial oxygen consumption. BU administration inhibited chemokine CCL2 expression, accumulation of monocytes/macrophages, 8-OHdG generation, mitochondrial ROS generation, and proinflammatory cytokine expression, and markedly ameliorated the outcome of the TBI model. Yet, BU did not inhibit microglial activation or expression of TGFβ1 and insulin-like growth factor 1 (IGF-1). These results indicate that macrophages are the major aggravating cell type in TBI lesions, in particular during the acute phase. Activated microglia may even play favorable roles. Reduction of cellular energy metabolism in macrophages and suppression of CCL2 expression in injured tissue may lead to amelioration of TBI.
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http://dx.doi.org/10.1002/glia.23469DOI Listing
October 2018