Hemodialysis with Cohort Isolation to Prevent Secondary Transmission during a COVID-19 Outbreak in Korea.

BACKGROUND: Health care-associated infections during previous coronavirus epidemics involving severe acute respiratory syndrome and Middle East respiratory syndrome resulted from human-to-human transmission in hemodialysis (HD) facilities. The effect of a strategy of HD with cohort isolation-separate dialysis sessions for close contacts of patients with confirmed coronavirus disease 2019 (COVID-19)-on the prevention of secondary transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in HD units is unknown. METHODS: Our multicenter cohort study of an HD with cohort isolation strategy enrolled close contacts of patients with confirmed COVID-19, including patients on HD and health care workers in HD units. Close contacts had been identified by epidemiologic investigation and tested negative on an immediate screening test for SARS-CoV-2. RESULTS: As of March 14, 11 patients on HD and 7 health care workers from 11 HD centers were diagnosed as having COVID-19. The immediate screening test was performed in 306 people, and among them, 302 close contacts with negative test results were enrolled. HD with cohort isolation was performed among all close contacts for a median of 14 days in seven centers. During cohort isolation, nine patients showed symptoms but tested negative for SARS-CoV-2. Two health care workers in the HD units (0.66% of the total group) were diagnosed at the termination test for SARS-CoV-2. CONCLUSIONS: The transmission of COVID-19 can be controlled without closure of HD centers by implementing preemptive activities, including early detection with rapid testing, cohort isolation, collaboration between institutions, and continuous monitoring of infection. Our strategy and experience may provide helpful guidance for circumstances involving the rapid spread of infectious diseases such as COVID-19.

Association of Body Composition With Survival and Treatment Efficacy in Castration-Resistant Prostate Cancer.

Objectives: The association of body composition with survival and the efficacy of first-line treatment was investigated in patients with castration-resistant prostate cancer (CRPC). Methods: The records of CRPC patients treated with docetaxel or androgen receptor signaling inhibitors (ARSi) between 2005 and 2018 were reviewed. Skeletal muscle index (SMI), visceral fat index, and subcutaneous fat index were evaluated using pretreatment computed tomography images. Results: Of 230 eligible patients, 144 received docetaxel, and 86 received ARSi as the first-line treatment for CRPC. The SMIhi (based on median values) group had higher prostate-specific antigen (PSA) progression-free survival (median 13.5 vs. 8.3 months, p = 0.030), radiologic progression-free survival (14.9 vs. 9.1 months, p < 0.001), and overall survival (24.1 vs. 16.9 months, p = 0.015) than the SMIlo group. In docetaxel-treated patients, the SMIhi group had higher PSA progression-free survival (13.5 vs. 5.9 months, p = 0.016) and radiologic progression-free survival (14.6 vs. 6.7 months, p < 0.001) than the SMIlo group. However, PSA progression-free survival and radiologic progression-free survival were comparable between the two groups in ARSi-treated patients. SMI was independently associated with the risk of radiologic progression in patients treated with docetaxel but not in those treated with ARSi. Conclusions: High skeletal muscle mass may be associated with reduced risk of disease progression and mortality in patients with CRPC. However, the significance of these relationships is limited in patients treated with docetaxel. These results suggest that assessing skeletal muscle mass may be worthwhile when selecting treatments for CRPC; however, further prospective validation and large-scale studies are needed.

Visceral fat measured by computed tomography and the risk of breast cancer.

BACKGROUND: Obesity is a risk factor for the development of breast cancer, which can be examined to assess the association between abdominal fat distribution through computed tomography (CT) and risk of breast cancer by hormone receptor (HR) status in women. METHODS: We examined 234 cases of newly diagnosed breast cancer patients and 211 controls consisting of health examinees in the Republic of Korea. The abdominal body fat distribution was measured by CT scan. The subjects' medical information, obtained from electronic medical records (EMR), were analyzed to verify the association between visceral fat and the type of breast cancer by HRs. RESULTS: While visceral obesity increased the risk of breast cancer in post-menopausal women by 1.50 (95% CI, 0.75-2.98), the effect was not observed in pre-menopausal women 0.86 (95% CI, 0.44-1.62). Also, histological grade was associated with visceral fat, which higher histological grade score (≥2) showed a slightly increased mortality rate (r=0.15, P=0.07). Patients with negative progesterone receptors tended to have a higher abdominal fat ratio than patients with positive progesterone receptors. Especially in pre-menopausal women, higher distribution of abdominal fat ratio in breast cancer patients had somewhat more of an effect on negative than positive HRs [estrogen receptor (ER), P=0.12; progesterone receptor (PR), P=0.06; human epidermal growth factor receptor 2 (HER2), P=0.43]. CONCLUSIONS: Our results suggest that the clear association between breast cancer and distribution of abdominal fat, and the abdominal fat ratio, are useful indicators for risk factors for breast cancer as well as malignancy.

Breast Cancer Risk Associations with Digital Mammographic Density by Pixel Brightness Threshold and Mammographic System.

Purpose To compare three mammographic density measures defined by different pixel intensity thresholds as predictors of breast cancer risk for two different digital mammographic systems. Materials and Methods The Korean Breast Cancer Study included 398 women with invasive breast cancer and 737 control participants matched for age at mammography (±1 year), examination date, mammographic system, and menopausal status. Mammographic density was measured by using the automated Laboratory for Individualized Breast Radiodensity Assessment (LIBRA) software and the semiautomated Cumulus software at the conventional threshold (Cumulus) and at increasingly higher thresholds (Altocumulus and Cirrocumulus, respectively). Measures were Box-Cox-transformed and adjusted for age, body mass index, and menopausal status. Conditional logistic regression was used to estimate risk associations. For calculation of measures of predictive value, the change in odds per standard deviation (OPERA) and the area under the receiver operating characteristic curve (AUC) were used. Results For dense area, with use of the direct conversion system the OPERAs were 1.72 (95% confidence interval [CI]: 1.38, 2.15) for LIBRA, 1.58 (95% CI: 1.27, 1.97) for Cumulus, 2.04 (95% CI: 1.60, 2.59) for Altocumulus, and 3.48 (95% CI: 2.45, 4.47) for Cirrocumulus (P < .001). The corresponding AUCs were 0.70, 0.69, 0.76, and 0.89, respectively. With use of the indirect conversion system, the corresponding OPERAs were 1.50 (95% CI: 1.28, 1.76), 1.36 (95% CI: 1.16, 1.59), 1.40 (95% CI: 1.19, 1.64), and 1.47 (95% CI: 1.25, 1.73) (P < .001) and the AUCs were 0.64, 0.60, 0.61, and 0.63, respectively. Conclusion It is possible that mammographic density defined by higher pixel thresholds could capture more risk-predicting information with use of a direct conversion mammographic system; the mammographically bright, rather than white, regions are etiologically important. © RSNA, 2017.

A study of the effects of synthesis conditions on Li5FeO4/carbon nanotube composites.

Li5FeO4/carbon nanotube (LFO/CNT) composites composed of sub-micron sized LFO and a nanocarbon with high electrical conductivity were successfully synthesized for the use as lithium ion predoping source in lithium ion cells. The phase of LFO in the composite was found to be very sensitive to the synthesis conditions, such as the heat treatment temperature, type of lithium salt, and physical state of the precursors (powder or pellet), due to the carbothermic reduction of Fe3O4 by CNTs during high temperature solid state reaction. Under optimized synthesis conditions, LFO/CNT composites could be synthesized without the formation of impurities. To the best of our knowledge, this is the first report on the synthesis and characterization of a sub-micron sized LFO/CNT composites.

Investigation of Factors Affecting Body Temperature Changes During Routine Clinical Head Magnetic Resonance Imaging.

BACKGROUND: Pulsed radiofrequency (RF) magnetic fields, required to produce magnetic resonance imaging (MRI) signals from tissue during the MRI procedure have been shown to heat tissues. OBJECTIVES: To investigate the relationship between body temperature rise and the RF power deposited during routine clinical MRI procedures, and to determine the correlation between this effect and the body's physiological response. PATIENTS AND METHODS: We investigated 69 patients from the Korean national cancer center to identify the main factors that contribute to an increase in body temperature (external factors and the body's response) during a clinical brain MRI. A routine protocol sequence of MRI scans (1.5 T and 3.0 T) was performed. The patient's tympanic temperature was recorded before and immediately after the MRI procedure and compared with changes in variables related to the body's physiological response to heat. RESULTS: Our investigation of the physiological response to RF heating indicated a link between increasing age and body temperature. A higher increase in body temperature was observed in older patients after a 3.0-T MRI (r = 0.07, P = 0.29 for 1.5-T MRI; r = 0.45, P = 0.002 for 3.0-T MRI). The relationship between age and body heat was related to the heart rate (HR) and changes in HR during the MRI procedure; a higher RF power combined with a reduction in HR resulted in an increase in body temperature. CONCLUSION: A higher magnetic field strength and a decrease in the HR resulted in an increase in body temperature during the MRI procedure.

Synthesis of Reduced Graphene Oxide-Modified LiMn0.75Fe0.25PO4 Microspheres by Salt-Assisted Spray Drying for High-Performance Lithium-Ion Batteries.

Microsized, spherical, three-dimensional (3D) graphene-based composites as electrode materials exhibit improved tap density and electrochemical properties. In this study, we report 3D LiMn0.75Fe0.25PO4/reduced graphene oxide microspheres synthesized by one-step salt-assisted spray drying using a mixed solution containing a precursor salt and graphene oxide and a subsequent heat treatment. During this process, it was found that the type of metal salt used has significant effects on the morphology, phase purity, and electrochemical properties of the synthesized samples. Furthermore, the amount of the chelating agent used also affects the phase purity and electrochemical properties of the samples. The composite exhibited a high tap density (1.1 g cm(-3)) as well as a gravimetric capacity of 161 mA h g(-1) and volumetric capacity of 281 mA h cm(-3) at 0.05 C-rate. It also exhibited excellent rate capability, delivering a discharge capacity of 90 mA h g(-1) at 60 C-rate. Furthermore, the microspheres exhibited high energy efficiency and good cyclability, showing a capacity retention rate of 93% after 1000 cycles at 10 C-rate.

Analysis of the relationship between liver regeneration rate and blood levels.

OBJECTIVES: The aim of this study was to investigate the difference of liver function changes according to the liver regeneration rate after liver transplantation through blood tests. METHODS: Fifty donors, who underwent computed tomography (CT) 3D volumetry, were analyzed before and after liver transplantation. CT 3D volumetry was used as a study method to measure the mean liver regeneration volume and regeneration rate. Then, blood levels were measured including alanine transaminase (ALT), aminotransferase (AST), gamma-glutamyl transpeptidase (GGT) and total bilirubin. RESULTS: The liver regeneration rate rapidly increased from 39.13±4.91% befoone1 month and 90.31±13.09% 16 months after surgery furthermore. Blood levels rapidly increased 7 days after surgery and then decreased 16 months after surgery compared to the state before surgery. CONCLUSION: This study results could be used as a basis for the prognosis of future liver transplantations.

High-Surface-Area Nitrogen-Doped Reduced Graphene Oxide for Electric Double-Layer Capacitors.

A two-step method consisting of solid-state microwave irradiation and heat treatment under NH3 gas was used to prepare nitrogen-doped reduced graphene oxide (N-RGO) with a high specific surface area (1007 m(2) g(-1) ), high electrical conductivity (1532 S m(-1) ), and low oxygen content (1.5 wt %) for electrical double-layer capacitor applications. The specific capacitance of N-RGO was 291 F g(-1) at a current density of 1 A g(-1) , and a capacitance of 261 F g(-1) was retained at 50 A g(-1) , which indicated a very good rate capability. N-RGO also showed excellent cycling stability and preserved 96 % of the initial specific capacitance after 100 000 cycles. Near-edge X-ray absorption fine-structure spectroscopy results provided evidenced for the recovery of π conjugation in the carbon networks with the removal of oxygenated groups and revealed chemical bonding of the nitrogen atoms in N-RGO. The good electrochemical performance of N-RGO is attributed to its high surface area, high electrical conductivity, and low oxygen content.

Genotoxic effects of 3 T magnetic resonance imaging in cultured human lymphocytes.

The clinical and preclinical use of high-field intensity (HF, 3 T and above) magnetic resonance imaging (MRI) scanners have significantly increased in the past few years. However, potential health risks are implied in the MRI and especially HF MRI environment due to high-static magnetic fields, fast gradient magnetic fields, and strong radiofrequency electromagnetic fields. In this study, the genotoxic potential of 3 T clinical MRI scans in cultured human lymphocytes in vitro was investigated by analyzing chromosome aberrations (CA), micronuclei (MN), and single-cell gel electrophoresis. Human lymphocytes were exposed to electromagnetic fields generated during MRI scanning (clinical routine brain examination protocols: three-channel head coil) for 22, 45, 67, and 89 min. We observed a significant increase in the frequency of single-strand DNA breaks following exposure to a 3 T MRI. In addition, the frequency of both CAs and MN in exposed cells increased in a time-dependent manner. The frequencies of MN in lymphocytes exposed to complex electromagnetic fields for 0, 22, 45, 67, and 89 min were 9.67, 11.67, 14.67, 18.00, and 20.33 per 1000 cells, respectively. Similarly, the frequencies of CAs in lymphocytes exposed for 0, 45, 67, and 89 min were 1.33, 2.33, 3.67, and 4.67 per 200 cells, respectively. These results suggest that exposure to 3 T MRI induces genotoxic effects in human lymphocytes.