172 research outputs found

    All-plastic electrochemical transistor for glucose sensing using a ferrocene mediator.

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    We demonstrate a glucose sensor based on an organic electrochemical transistor (OECT) in which the channel, source, drain, and gate electrodes are made from the conducting polymer poly(3,4-ethylenedioxythiophene) doped with poly(styrene sulfonate) (PEDOT:PSS). The OECT employs a ferrocene mediator to shuttle electrons between the enzyme glucose oxidase and a PEDOT:PSS gate electrode. The device can be fabricated using a one-layer patterning process and offers glucose detection down to the micromolar range, consistent with levels present in human saliva

    Diffuse Interstitial Infiltrative Lung Metastasis of Malignant Melanoma: a Case Report

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    A diffuse interstitial infiltrative pattern of lung metastasis in a patient with malignant melanoma is rare and can be confused with benign conditions such as pulmonary edema or drug-induced pneumonitis. We experienced a case of diffuse interstitial infiltrative lung metastasis in malignant melanoma in a 37-year-old man. This case was confirmed by a transbronchial lung biopsy. We herein describe the findings on CT and positron emission tomography scan

    Baseline heart rate variability in children and adolescents with vasovagal syncope

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    PurposeThis study aimed to evaluate the autonomic imbalance in syncope by comparing the baseline heart rate variability (HRV) between healthy children and those with vasovagal syncope.MethodsTo characterize the autonomic profile in children experiencing vasovagal syncope, we evaluated the HRV of 23 patients aged 7-18 years and 20 healthy children. These children were divided into preadolescent (<12 years) and adolescent groups. The following time-domain indices were calculated: root mean square of the successive differences (RMSSD); standard deviation of all average R-R intervals (SDNN); and frequency domain indices including high frequency (HF), low frequency (LF), normalized high frequency, normalized low frequency, and low frequency to high frequency ratio (LF/HF).ResultsHRV values were significantly different between healthy children and those with syncope. Student t test indicated significantly higher SNDD values (60.46 ms vs. 37.42 ms, P=0.003) and RMSSD (57.90 ms vs. 26.92 ms, P=0.000) in the patient group than in the control group. In the patient group, RMSSD (80.41 ms vs. 45.89 ms, P=0.015) and normalized HF (61.18 ms vs. 43.19 ms, P=0.022) were significantly higher in adolescents, whereas normalized LF (38.81 ms vs. 56.76 ms, P=0.022) and LF/HF ratio (0.76 vs. 1.89, P=0.041) were significantly lower in adolescents. In contrast, the control group did not have significant differences in HRV values between adolescents and preadolescents.ConclusionThe results of this study indicated that children with syncope had a decreased sympathetic tone and increased vagal tone compared to healthy children. Additionally, more severe autonomic imbalances possibly occur in adolescents than in preadolescents

    Impact of pulmonary artery pressure on recurrence after catheter ablation in patients with atrial fibrillation

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    BackgroundThe pulmonary veins play a major role in the pathogenesis of atrial fibrillation (AF) and may be affected by cardiac remodeling due to pulmonary vascular dysfunction. It remains to be determined whether pulmonary artery pressure (PAP) is associated with the recurrence of AF after radiofrequency catheter ablation (RFCA).MethodsConsecutive patients with paroxysmal and persistent AF who underwent RFCA, including wide circumferential pulmonary vein isolation, were analyzed. Systolic PAP was measured using transthoracic echocardiography, and clinical outcomes were compared between patients with PAP &lt;35 mmHg and those with PAP ≥35 mmHg.ResultsAmong 2,379 patients (mean age 56.7 ± 10.6 years, 77% men), 1,893 (79.6%) had PAP &lt;35 mmHg and 486 (20.4%) had PAP ≥35 mmHg. During the median follow-up of 25.4 months, in patients with paroxysmal AF (n = 1,294), the recurrence rate was significantly greater in the PAP ≥35 mmHg group than in the PAP &lt;35 mmHg group (35.1% vs. 23.8%, log-rank p = 0.008). However, in patients with persistent AF (n = 1,085), the recurrence rate was not significantly different between the two groups (52.2% vs. 49.7%, log-rank p = 0.409). Multivariate analysis using Cox regression showed that PAP ≥35 mmHg was significantly associated with clinical recurrence (hazard ratio 1.19, 95% confidence interval 1.02–1.40, p = 0.027).ConclusionThis study showed that a higher PAP was associated with an increased risk of recurrence after RFCA in patients with paroxysmal AF, suggesting a mechanism by which a pulmonary vascular pathology may cause impairment of the pulmonary veins and remodeling of the left atrium

    Effect of ketamine pretreatment for anaesthesia in patients undergoing percutaneous transluminal balloon angioplasty with continuous remifentanil infusion

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    BACKGROUND: An appropriate level of sedation and pharmacological assist are essential during percutaneous transluminal balloon angioplasty (PTA). Ketamine provides good analgesia while preserving airway patency, ventilation, and cardiovascular stability with an opioid sparing effect suggesting that it would be ideal in combination with remifentanil and midazolam in spontaneously breathing patients. We evaluated the effect of a small dose of ketamine added to midazolam and remifentanil on analgesia/sedation for PTA procedures. METHODS: Sixty-four patients receiving PTA were enrolled. The Control group received midazolam 1.0 mg i.v. and continuous infusion of remifentanil 0.05 µg/kg/min. The Ketamine group received, in addition, an intravenous bolus of 0.5 mg/kg ketamine. Patients' haemodynamic data were monitored before remifentanil infusion, 5 min after remifentanil infusion, at 1, 3, 5, 30 min after incision, and at admission to the recovery room. Verbal numerical rating scales (VNRS) and sedation [OAA/S (Observer's Assessment of Alertness/Sedation)] scores were also recorded. RESULTS: The VNRS values at 1, 3, and 5 min after incision and OAA/S scores at 5 min after remifentanil infusion, and 1, 3, and 5 min after incision were lower in the Ketamine group than in the Control group. In the Control group, the VNRS value at 1 min after incision significantly increased and OAA/S values at 3, 5, and 30 min after incision significantly decreased compared to baseline values, while there were no significant changes in the ketamine group. CONCLUSIONS: A small dose of ketamine as an adjunct sedative to the combination of midazolam and remifentanil produced a better quality of sedation and analgesia than without ketamine and provided stable respiration without cardiopulmonary deterioration.ope

    Clinical Characteristics of a Nationwide Hospital-based Registry of Mild-to-Moderate Alzheimer's Disease Patients in Korea: A CREDOS (Clinical Research Center for Dementia of South Korea) Study

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    With rapid population aging, the socioeconomic burden caused by dementia care is snowballing. Although a few community-based studies of Alzheimer's disease (AD) have been performed in Korea, there has never been a nationwide hospital-based study thereof. We aimed to identify the demographics and clinical characteristics of mild-to-moderate AD patients from the Clinical Research Center for Dementia of Korea (CREDOS) registry. A total of 1,786 patients were consecutively included from September 2005 to June 2010. Each patient underwent comprehensive neurological examination, interview for caregivers, laboratory investigations, neuropsychological tests, and brain MRI. The mean age was 74.0 yr and the female percentage 67.0%. The mean period of education was 7.1 yr and the frequency of early-onset AD (< 65 yr old) was 18.8%. Among the vascular risk factors, hypertension (48.9%) and diabetes mellitus (22.3%) were the most frequent. The mean score of the Korean version of Mini-Mental State Examination (K-MMSE) was 19.2 and the mean sum of box scores of Clinical Dementia Rating (CDR-SB) 5.1. Based on the well-structured, nationwide, and hospital-based registry, this study provides the unique clinical characteristics of AD and emphasizes the importance of vascular factors in AD in Korea

    Prediction of cognitive impairment via deep learning trained with multi-center neuropsychological test data

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    Background Neuropsychological tests (NPTs) are important tools for informing diagnoses of cognitive impairment (CI). However, interpreting NPTs requires specialists and is thus time-consuming. To streamline the application of NPTs in clinical settings, we developed and evaluated the accuracy of a machine learning algorithm using multi-center NPT data. Methods Multi-center data were obtained from 14,926 formal neuropsychological assessments (Seoul Neuropsychological Screening Battery), which were classified into normal cognition (NC), mild cognitive impairment (MCI) and Alzheimers disease dementia (ADD). We trained a machine learning model with artificial neural network algorithm using TensorFlow (https://www.tensorflow.org) to distinguish cognitive state with the 46-variable data and measured prediction accuracies from 10 randomly selected datasets. The features of the NPT were listed in order of their contribution to the outcome using Recursive Feature Elimination. Results The ten times mean accuracies of identifying CI (MCI and ADD) achieved by 96.66 ± 0.52% of the balanced dataset and 97.23 ± 0.32% of the clinic-based dataset, and the accuracies for predicting cognitive states (NC, MCI or ADD) were 95.49 ± 0.53 and 96.34 ± 1.03%. The sensitivity to the detection CI and MCI in the balanced dataset were 96.0 and 96.0%, and the specificity were 96.8 and 97.4%, respectively. The time orientation and 3-word recall score of MMSE were highly ranked features in predicting CI and cognitive state. The twelve features reduced from 46 variable of NPTs with age and education had contributed to more than 90% accuracy in predicting cognitive impairment. Conclusions The machine learning algorithm for NPTs has suggested potential use as a reference in differentiating cognitive impairment in the clinical setting.The publication costs, design of the study, data management and writing the manuscript for this article were supported by the Ministry of Education of the Republic of Korea and the National Research Foundation of Korea (NRF-2017S1A6A3A01078538), Korea Ministry of Health & Welfare, and from the Original Technology Research Program for Brain Science through the National Research Foundation of Korea funded by the Korean Government (MSIP; No. 2014M3C7A1064752)

    Type I Interferon Signaling Regulates Ly6Chi Monocytes and Neutrophils during Acute Viral Pneumonia in Mice

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    Type I interferon (IFN-I) plays a critical role in the homeostasis of hematopoietic stem cells and influences neutrophil influx to the site of inflammation. IFN-I receptor knockout (Ifnar1−/−) mice develop significant defects in the infiltration of Ly6Chi monocytes in the lung after influenza infection (A/PR/8/34, H1N1). Ly6Chi monocytes of wild-type (WT) mice are the main producers of MCP-1 while the alternatively generated Ly6Cint monocytes of Ifnar1−/− mice mainly produce KC for neutrophil influx. As a consequence, Ifnar1−/− mice recruit more neutrophils after influenza infection than do WT mice. Treatment of IFNAR1 blocking antibody on the WT bone marrow (BM) cells in vitro failed to differentiate into Ly6Chi monocytes. By using BM chimeric mice (WT BM into Ifnar1−/− and vice versa), we confirmed that IFN-I signaling in hematopoietic cells is required for the generation of Ly6Chi monocytes. Of note, WT BM reconstituted Ifnar1−/− chimeric mice with increased numbers of Ly6Chi monocytes survived longer than influenza-infected Ifnar1−/− mice. In contrast, WT mice that received Ifnar1−/− BM cells with alternative Ly6Cint monocytes and increased numbers of neutrophils exhibited higher mortality rates than WT mice given WT BM cells. Collectively, these data suggest that IFN-I contributes to resistance of influenza infection by control of monocytes and neutrophils in the lung
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