182 research outputs found

    Changes in motor synergies for tracking movement and responses to perturbations depend on task-irrelevant dimension constraints

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    We investigated the changes in the motor synergies of target-tracking movements of hands and the responses to perturbation when the dimensionalities of target positions were changed. We used uncontrolled manifold (UCM) analyses to quantify the motor synergies. The target was changed from one to two dimensions, and the direction orthogonal to the movement direction was switched from task-irrelevant directions to task-relevant directions. The movement direction was task-relevant in both task conditions. Hence, we evaluated the effects of constraints on the redundant dimensions on movement tracking. Moreover, we could compare the two types of responses to the same directional perturbations in one- and two-dimensional target tasks. In the one-dimensional target task, the perturbation along the movement direction and the orthogonal direction were task-relevant and -irrelevant perturbations, respectively. In the two-dimensional target task, the both perturbations were task-relevant perturbations. The results of the experiments showed that the variabilities of the hand positions in the two-dimensional target-tracking task decreased, but the variances of the joint angles did not significantly change. For the task-irrelevant perturbations, the variances of the joint angles within the UCM that did not affect hand position (UCM component) increased. For the task-relevant perturbations, the UCM component tended to increase when the available UCM was large. These results suggest that humans discriminate whether the perturbations were task-relevant or -irrelevant and then adjust the responses of the joints by utilizing the available UCM

    Diverse reaction behaviors of artificial ubiquinones in mitochondrial respiratory complex I

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    The ubiquinone (UQ) reduction step catalyzed by NADH-UQ oxidoreductase (mitochondrial respiratory complex I) is key to triggering proton translocation across the inner mitochondrial membrane. Structural studies have identified a long, narrow, UQ-accessing tunnel within the enzyme. We previously demonstrated that synthetic oversized UQs, which are unlikely to transit this narrow tunnel, are catalytically reduced by native complex I embedded in submitochondrial particles but not by the isolated enzyme. To explain this contradiction, we hypothesized that access of oversized UQs to the reaction site is obstructed in the isolated enzyme because their access route is altered following detergent solubilization from the inner mitochondrial membrane. In the present study, we investigated this using two pairs of photoreactive UQs (pUQ(m-1)/pUQ(p-1) and pUQ(m-2)/pUQ(p-2)), with each pair having the same chemical properties except for a similar to 1.0 angstrom difference in side-chain widths. Despite this subtle difference, reduction of the wider pUQs by the isolated complex was significantly slower than of the narrower pUQs, but both were similarly reduced by the native enzyme. In addition, photoaffinity-labeling experiments using the four [I-125]pUQs demonstrated that their side chains predominantly label the ND1 subunit with both enzymes but at different regions around the tunnel. Finally, we show that the suppressive effects of different types of inhibitors on the labeling significantly changed depending on [I-125]pUQs used, indicating that [I-125]pUQs and these inhibitors do not necessarily share a common binding cavity. Altogether, we conclude that the reaction behaviors of pUQs cannot be simply explained by the canonical UQ tunnel model.Peer reviewe

    Risk factors of first bite syndrome

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    Objective : First bite syndrome is a complication of surgical resection of parapharyngeal space tumors and the development of cramping pain in the parotid region with the first bite of a meal. The present study aimed to identify the potential risk factors for the development of first bite syndrome. Methods : We retrospectively reviewed 30 consecutive patients with parapharyngeal space tumors who had been surgically treated between August 2003 and December 2015 at our department. Results : The tumor site (prestyloid or retrostyloid) and surgical approach (transcervical-parotid, transparotid, or transcervical) were not correlated with the development of first bite syndrome. Ligation and mobilization of the external carotid artery was significantly correlated with the development of first bite syndrome. Moreover, patients with complete resection of the parotid gland did not experience first bite syndrome. Discussion : The present findings suggest that concomitant surgical settings of 1) sympathetic denervation of the parotid gland with ligation of the external carotid artery or injury of the sympathetic nerve plexus around the external carotid artery during its mobilization, and 2) residual parotid gland tissue are risk factors for the development of first bite syndrome after surgical resection of parapharyngeal space tumors

    Ectopic Breast Cancer Arising within an Axillary Lymph Node

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    We report our experience with the diagnosis and treatment of an ectopic breast cancer arising within an axillary lymph node. The patient was a 65-year-old woman diagnosed breast cancer and axillary lymph node metastasis. We performed a partial mastectomy and axillary lymph node dissection. Postoperative pathology revealed no malignant lesions in the breast; however, a nodule in one of axillary lymph nodes had mixed benign and malignant components, leading to a diagnosis of invasive ductal carcinoma derived from ectopic mammary tissue. This case represents a very rare form of breast cancer, and the malignancy was difficult to distinguish from metastasis

    Current Multidisciplinary Approach to Fertility Preservation for Breast Cancer Patients

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    Adverse effects on fertility are a significant problem for premenopausal breast cancer patients. Since April 2009, we have been referring young patients for fertility counseling provided by a multidisciplinary team. Here we evaluated the efficacy and safety of our current fertility preservation approach. We retrospectively analyzed the cases of 277 patients < 45 years old at diagnosis, which was made between 2009 and 2016. Seventy-two (26%) patients received fertility counseling. Seventeen (6%) of the 277 patients decided to preserve their fertility before starting adjuvant systemic therapy. Six (35%) patients underwent oocyte cryopreservation, and 11 (65%) married patients opted for embryo cryopreservation. There were no pregnancies among the patients undergoing oocyte cryopreservation, whereas 3 (27%) of the patients who opted for embryo cryopreservation became pregnant. Two (12%) patients stopped endocrine therapy after 2 years in an effort to become pregnant, but their breast cancers recurred. Though the problem of fertility loss for breast cancer patients is important and we should assess the infertility risk for all patients, we should also consider the prognosis. In June 2016, we launched a prospective multicenter cohort study to evaluate the efficacy and safety of fertility preservation in greater detail

    Usefulness of Fluorine-18-Fluorodeoxyglucose Positron Emission Tomography in a Patient With Takayasu\u27s Arteritis Associated With Antiphospholipid Syndrome

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    A 36-year-old woman was admitted for recurring chest pain and hemoptysis. Blood pressure in the right and left arms was equal, and no murmurs or bruits were heard. Body temperature was normal on admission and remained within the normal range during the hospital stay. C-reactive protein was slightly elevated (2.3 mg/dL) and lupus anticoagulant was positive. Angiography showed no abnormality of the aorta or its branches, but the left pulmonary artery showed occlusion at the proximal portion. Computed tomography (CT) revealed segmental wall thickening of the thoracic aorta. Fluorine-18-fluorodeoxyglucose positron emission tomography (18FDG PET) showed high uptake in the proximal portion of the left pulmonary artery and in the thoracic aorta with wall thickening on CT. Based on these findings, a diagnosis of Takayasu\u27s arteritis associated with antiphospholipid syndrome was made and high-dose steroid therapy (prednisolone 30 mg/day) was started. Two months later, the C-reactive protein level had decreased from 2.3 mg/dL to 1.1 mg/dL, and both the focal wall thickening and 18FDG uptake of the thoracic aorta were decreased. 18FDG PET was useful for evaluating the efficacy of the steroid therapy in addition to making a diagnosis of Takayasu\u27s arteritis associated with antiphospholipid syndrome

    Complement C9 expression is associated with damaged myocardial cells in pediatric sudden death cases of fulminant myocarditis.

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    Background:Because disease progression is so fast in sudden death of acute fulminant myocarditis, damage of myocardial cells is not evident in routine hematoxylin and eosin staining. To understand damage to myocardial cells and the mechanism of sudden death, immunohistochemical staining was performed for two forensic autopsy cases.Case presentation:The patients were a healthy 5-year-old girl and 8-year-old boy. They suddenly died within 2 days of appearance of flu-like symptoms. An autopsy showed accumulation of yellowish-clear pericardial fluid containing fibrin deposits, fluid blood in the heart, and congestion of visceral organs. Histologically, minor necrosis or degeneration of myocardial cells with mainly lymphocytic infiltration was observed sometimes in tissue sections. Immunohistochemically, positive complement C9 staining and negative sirtuin 1 staining were found. These findings suggested wide damage of myocardial cells, even in regions with no marked changes in myocardial cells with hematoxylin and eosin staining. These areas corresponded to those with strong accumulation of lymphocytes.Conclusions:Immunohistochemistry for complement C9 and sirtuin 1 might become a new tool for evaluating damage of myocardial cells of fulminant acute myocarditis

    The ASTRO-H X-ray Observatory

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    The joint JAXA/NASA ASTRO-H mission is the sixth in a series of highly successful X-ray missions initiated by the Institute of Space and Astronautical Science (ISAS). ASTRO-H will investigate the physics of the high-energy universe via a suite of four instruments, covering a very wide energy range, from 0.3 keV to 600 keV. These instruments include a high-resolution, high-throughput spectrometer sensitive over 0.3-2 keV with high spectral resolution of Delta E < 7 eV, enabled by a micro-calorimeter array located in the focal plane of thin-foil X-ray optics; hard X-ray imaging spectrometers covering 5-80 keV, located in the focal plane of multilayer-coated, focusing hard X-ray mirrors; a wide-field imaging spectrometer sensitive over 0.4-12 keV, with an X-ray CCD camera in the focal plane of a soft X-ray telescope; and a non-focusing Compton-camera type soft gamma-ray detector, sensitive in the 40-600 keV band. The simultaneous broad bandpass, coupled with high spectral resolution, will enable the pursuit of a wide variety of important science themes.Comment: 22 pages, 17 figures, Proceedings of the SPIE Astronomical Instrumentation "Space Telescopes and Instrumentation 2012: Ultraviolet to Gamma Ray
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